Solid-state battery

Abstract

A solid-state battery is provided. The solid-state battery has a solid-state battery laminate that has at least one cell structure unit that has a positive electrode layer, a negative electrode layer, and a solid electrolyte layer interposed between the positive electrode layer and the negative electrode layer. The solid-state battery has external terminals provided on opposite side surfaces of the solid-state battery laminate, respectively. The solid-state battery further has an outer packaging member that covers the solid-state battery laminate, and a gap exists on the inner side of the outer packaging member on a side adjacent to the solid-state battery laminate.

Description

TECHNICAL FIELD

[0001] The present application relates to a solid-state battery. More specifically, the present application relates to a solid-state battery provided with an outer packaging member in a manner of covering a solid-state battery laminate. BACKGROUND

[0002] In the past, secondary batteries capable of repeating charge and discharge have been used for various purposes. For example, secondary batteries are used as power sources for electronic devices such as smartphones and notebook computers.

[0003] In a secondary battery, a liquid electrolyte is generally used as a medium for moving ions that contribute to charge and discharge. That is, so-called electrolytic solution is used for a secondary battery. However, in such a secondary battery, safety is generally required in terms of preventing leakage of the electrolytic solution. In addition, since an organic solvent or the like used for the electrolytic solution is a flammable substance, safety is also required in this regard.

[0004] Therefore, a solid-state battery using a solid electrolyte instead of an electrolytic solution has been studied.

[0005] PRIOR ART DOCUMENTS

[0006] PATENT LITERATURE

[0007] Patent Literature 1: Japanese Patent Application Publication No. 2015-220106

[0008] Patent Literature 2: Japanese Patent Application Publication No. 2015-220107 SUMMARY

[0009] PROBLEMS TO BE SOLVED BY THE INVENTION

[0010] The present inventors and the like have noted that there are technical problems that need to be overcome in the past solid-state battery, and have found it necessary to take appropriate measures. Specifically, the present inventors and the like have found that the following technical problems exist.

[0011] For example, as described in Patent Literature 1, in a solid-state battery, a solid electrolyte is used instead of an electrolytic solution. Therefore, in a solid-state battery, a solid electrolyte is used as a medium for moving ions that contribute to charge and discharge. Figure 15As shown, the existing solid-state battery 100 is formed of a solid-state battery stack (or a battery main body) that has at least one battery structure unit 105 having a positive electrode layer 101, a negative electrode layer 102, and a solid electrolyte layer 103 interposed therebetween, along a stacking direction. Such a battery main body has an inorganic layer such as a silicon oxynitride thin film formed by sputtering as a waterproof layer 110 having a thickness of about 5 to 1000 nm. It has been found by the inventors of the present application that such a waterproof layer 110 having a film thickness of this order cannot withstand stress due to expansion or contraction of the battery main body during charging and discharging of the solid-state battery, and can be broken or damaged, and the like. In addition, it has been found by the inventors of the present application that, in a waterproof layer 110 composed of such an inorganic layer, if a break or damage, and the like occurs, moisture or water vapor enters the battery main body, and the performance of the solid-state battery is significantly reduced.

[0012] In addition, in the existing solid-state battery 100, a resin layer 120 formed of silicone rubber, fluorine resin, or the like can be further provided on the upper side of the waterproof layer 110, but it has been found by the inventors of the present application that such a resin layer 120 can allow water vapor to pass through and cause water vapor to enter the battery main body, and the gas barrier property is not sufficient.

[0013] The present application was completed in view of the above-described technical problems. That is, the main object of the present application is to provide a solid-state battery having an outer packaging member capable of suppressing the occurrence of a break or damage, and the like, and further improving the gas barrier property.

[0014] Technical solution for solving the technical problem

[0015] The inventors of the present application have attempted to solve the above-described technical problems by taking measures in a new direction, rather than extending and expanding on the existing technology. As a result, the present application of a solid-state battery that can achieve the above-described main object has been completed.

[0016] The present application provides a solid-state battery. The solid-state battery is formed of a solid-state battery stack having, for example, at least one battery structure unit having a positive electrode layer, a negative electrode layer, and a solid electrolyte layer interposed between the positive electrode layer and the negative electrode layer, along a stacking direction, and has external terminals of positive and negative electrode terminals, respectively, provided on opposite side surfaces of the solid-state battery stack, and further has an outer packaging member covering the solid-state battery stack, with a gap present on the inner side of the outer packaging member adjacent to the solid-state battery stack (or an interface).

[0017] Effect of the invention

[0018] In the present application, a solid-state battery having an outer packaging member capable of suppressing or preventing generation of cracks or defects and further improving gas barrier properties against water vapor and the like can be obtained. Note that the effects described in this specification are merely examples and are not limited thereto, and additional effects can be included. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 is a schematic view that schematically shows a solid-state battery laminate that can be used in a solid-state battery according to an embodiment of the present application.

[0020] Figure 2 is a schematic cross-sectional view that schematically shows an outer packaging member that can be used in a solid-state battery according to an embodiment of the present application.

[0021] Figure 3 is a schematic cross-sectional view that schematically shows another outer packaging member that can be used in a solid-state battery according to an embodiment of the present application.

[0022] Figure 4 is a schematic cross-sectional view that schematically shows an outer packaging member that can be used in a solid-state battery according to another embodiment of the present application.

[0023] Figure 5 is a schematic cross-sectional view that schematically shows another outer packaging member that can be used in a solid-state battery according to another embodiment of the present application.

[0024] Figure 6 is a schematic cross-sectional view that schematically shows a solid-state battery according to an embodiment of the present application.

[0025] Figure 7 is a schematic cross-sectional view that schematically shows a solid-state battery according to another embodiment of the present application.

[0026] Figure 8 is a photograph that partially shows a cross section of a solid-state battery according to an embodiment of the present application as an example.

[0027] Figure 9 is a schematic view that schematically shows presence of a gap in an outer packaging member.

[0028] Figure 10 formation of a cross section in cross-sectional observation of an outer packaging member is schematically shown.

[0029] Figure 11 shows a sample (scale: 10 μm) of an electron microscope photograph (SEM) showing a cross section of a solid-state battery.

[0030] Figure 12In a sample of an electron microscope photograph (SEM) showing a cross section of a solid-state battery, "an outer packaging member (inner side)" and "an outer packaging member (outer side)" are shown separately (scale: 10 μm).

[0031] Figure 13 In a sample of an electron microscope photograph (SEM) showing a cross section of a solid-state battery, a state in which both "an outer packaging member (inner side)" and "an outer packaging member (outer side)" are binarized is shown.

[0032] Figure 14 (A) of FIG. 1 shows a sample of an electron microscope photograph (SEM) showing a cross section of a solid-state battery, Figure 14 (B) of FIG. 1 shows a state in which a boundary between "an outer packaging member (inner side)" and "a battery main body (solid-state battery laminate)" is made clear and binarized in the sample, Figure 14 (C) of FIG. 1 shows a state in which a boundary between "an outer packaging member (inner side)" and "a battery main body (solid-state battery laminate)" is not made clear and "an outer packaging member (outer side)" and "an outer packaging member (inner side)" are binarized together.

[0033] Figure 15 is a schematic cross-sectional view schematically showing a conventional solid-state battery. DETAILED DESCRIPTION

[0034] Hereinafter, a "solid-state battery" of the present application, (for example, by Figure 6 , Figure 7 a solid-state battery specifically shown, particularly, an "outer packaging member" covering a solid-state battery laminate contained in the solid-state battery (for example, an outer packaging member shown in Figures 2 to 5 will be described in detail. Although the description is made with reference to the drawings as needed, the illustrated content is schematically and exemplarily shown for understanding the present application, and the appearance or the size ratio or the like can be different from the actual one.

[0035] The "cross-sectional observation" in the present specification means a form based on an observation from a direction substantially perpendicular to an arbitrary thickness direction of a solid-state battery (in short, for example, a form in a case where a section is taken on a plane parallel to the thickness direction).

[0036] The "vertical direction" and the "horizontal direction" used directly or indirectly in the present specification correspond to the vertical direction and the horizontal direction in the drawing, respectively.

[0037] The "front-rear direction" used directly or indirectly in the present specification corresponds to the front-rear direction of the paper surface in the drawing, respectively.

[0038] The same reference numerals or symbols indicate the same components, parts or the same meanings unless otherwise specified.

[0039] In a preferred embodiment, it can be understood that the vertical direction downward (i.e., the direction of gravity) is equivalent to the "downward direction" / "bottom side", and its opposite direction is equivalent to the "upward direction" / "top side".

[0040] In this invention, "solid-state battery" broadly refers to a battery in which the electrolyte, as a constituent element, is made of solid material; narrowly, it refers to an all-solid-state battery in which all constituent elements (particularly preferably all constituent elements) are made of solid material. In a preferred embodiment, the solid-state battery of this invention is a stacked solid-state battery configured as layers forming battery structural units, preferably with such layers being sintered bodies. It should be noted that "solid-state battery" includes not only so-called "secondary batteries" capable of repeated charging and discharging, but also "primary batteries" capable only of discharging. In a preferred embodiment of this invention, the "solid-state battery" is a secondary battery. The term "secondary battery" is not overly limited to this name; for example, it may also include "energy storage devices," etc.

[0041] The basic structure of the "solid-state battery" of the present invention will be described first, followed by the features of the solid-state battery (especially the "outer packaging component"). The structure of the solid-state battery described herein is merely an example for understanding the invention and is not intended to limit the invention.

[0042] [Basic Structure of Solid-State Batteries]

[0043] Solid-state batteries consist of at least two electrode layers (positive and negative) and a solid electrolyte layer (or solid electrolyte). Specifically, such as... Figure 1 As shown, the solid battery is formed by a solid battery stack 10 (hereinafter sometimes referred to as the "battery body"), which has at least one battery structure unit 5 along the stacking direction. The battery structure unit 5 has a positive electrode layer 1, a negative electrode layer 2 and a solid electrolyte layer (or solid electrolyte) 3 between them.

[0044] In the solid-state battery disclosed herein, there are no particular limitations on the stacked structure of the battery, particularly the structure of the battery structural units.

[0045] The solid-state battery disclosed herein may also be a single cell comprising only a battery structural unit, which consists of a positive electrode layer, a negative electrode layer, and a solid electrolyte layer (or solid electrolyte) between them.

[0046] In the solid-state battery of this disclosure, such battery structural units can be arranged in series or in parallel. From the viewpoint of stress dispersion, the battery structural units can be arranged in parallel.

[0047] Preferably, each layer constituting the solid battery can be formed by firing, and the positive electrode layer, the negative electrode layer, and the solid electrolyte layer, etc. can form a sintered layer. For example, the positive electrode layer, the negative electrode layer, and the solid electrolyte layer can be integrally sintered with each other, and thus the solid battery layer stack can form an integrated sintered body.

[0048] The positive electrode layer 1 is an electrode layer containing at least a positive electrode active material. Therefore, the positive electrode layer 1 can also be a positive electrode active material layer mainly composed of a positive electrode active material. The positive electrode layer can further contain a solid electrolyte as needed. In one embodiment, the positive electrode layer can be composed of a sintered body containing at least positive electrode active material particles and solid electrolyte particles.

[0049] On the other hand, the negative electrode layer 2 is an electrode layer containing at least a negative electrode active material. Therefore, the negative electrode layer 2 can also be a negative electrode active material layer mainly composed of a negative electrode active material. The negative electrode layer can further contain a solid electrolyte as needed. In one embodiment, the negative electrode layer can be composed of a sintered body containing at least negative electrode active material particles and solid electrolyte particles.

[0050] The positive electrode active material and the negative electrode active material are substances that participate in the intercalation and deintercalation of ions and the transfer of electrons to and from the external circuit in the solid battery. For example, ions move (conduct) between the positive electrode layer and the negative electrode layer via the solid electrolyte. The intercalation and deintercalation of ions into the active material is accompanied by oxidation or reduction of the active material, and electrons or holes for such oxidation-reduction reactions are transferred from the external circuit to the external terminals of the solid battery and further to the positive electrode layer or the negative electrode layer, whereby charging and discharging are performed. In particular, the positive electrode layer and the negative electrode layer can be layers capable of intercalating and deintercalating lithium ions or sodium ions. That is, the solid battery can be a full solid type secondary battery capable of charging and discharging of the battery by movement of lithium ions or sodium ions between the positive electrode layer and the negative electrode layer via the solid electrolyte.

[0051] (Positive electrode active material)

[0052] As the positive electrode active material that can be contained in the positive electrode layer 1, for example, at least one selected from the group consisting of a lithium-containing phosphoric acid compound having a NASICON-type structure, a lithium-containing phosphoric acid compound having an olivine-type structure, a lithium-containing layered oxide, and a lithium-containing oxide having a spinel-type structure, etc. can be exemplified. As an example of the lithium-containing phosphoric acid compound having a NASICON-type structure, Li3V2(PO4)3, etc. can be exemplified. As an example of the lithium-containing phosphoric acid compound having an olivine-type structure, Li3Fe2(PO4)3, LiFePO4, LiMnPO4, LiFe 0.6 Mn 0.4 PO4, etc. can be exemplified. As an example of the lithium-containing layered oxide, LiCoO2, LiCo 1 / 3 Ni1 / 3 Mn 1 / 3 O2, LiCo 0.8 Ni 0.15 Al 0.05 O2, etc. As an example of the lithium-containing oxide having a spinel structure, LiMn2O4, LiNi 0.5 Mn 1.5 O4, etc.

[0053] In addition, as the positive electrode active material capable of intercalating and deintercalating sodium ions, at least one selected from the group consisting of a sodium-containing phosphoric acid compound having a NASICON-type structure, a sodium-containing phosphoric acid compound having an olivine-type structure, a sodium-containing layered oxide, and a sodium-containing oxide having a spinel-type structure, etc. can be exemplified.

[0054] (Negative electrode active material)

[0055] As the negative electrode active material that can be contained in the negative electrode layer 2, at least one selected from the group consisting of an oxide (containing at least one element selected from the group consisting of Ti, Si, Sn, Cr, Fe, Nb, and Mo), a carbon material such as graphite, a graphite-lithium compound, a lithium alloy, a lithium-containing phosphoric acid compound having a NASICON-type structure, a lithium-containing phosphoric acid compound having an olivine-type structure, and a lithium-containing oxide having a spinel-type structure, etc. can be exemplified. As an example of the lithium alloy, Li-Al, etc. can be exemplified. As an example of the lithium-containing phosphoric acid compound having a NASICON-type structure, Li3V2(PO4)3, LiTi2(PO4)3, etc. can be exemplified. As an example of the lithium-containing phosphoric acid compound having an olivine-type structure, Li3Fe2(PO4)3, LiCuPO4, etc. can be exemplified. As an example of the lithium-containing oxide having a spinel-type structure, Li4Ti5O 12 , etc.

[0056] In addition, as the negative electrode active material capable of intercalating and deintercalating sodium ions, at least one selected from the group consisting of a sodium-containing phosphoric acid compound having a NASICON-type structure, a sodium-containing phosphoric acid compound having an olivine-type structure, and a sodium-containing oxide having a spinel-type structure, etc. can be exemplified.

[0057] The positive electrode layer and / or the negative electrode layer can contain a conductive aid. As the conductive aid that can be contained in the positive electrode layer and the negative electrode layer, at least one selected from the group consisting of a metal material such as silver, palladium, gold, platinum, copper, and nickel, and carbon, etc. can be exemplified.

[0058] In addition, the positive electrode layer and / or the negative electrode layer can contain a sintering aid. As the sintering aid, at least one selected from the group consisting of a lithium oxide, a sodium oxide, a potassium oxide, a boron oxide, a silicon oxide, a bismuth oxide, and a phosphorus oxide, etc. can be exemplified.

[0059] (Solid electrolyte)

[0060] The solid electrolyte 3 is, for example, a material capable of conducting lithium ions or sodium ions. In particular, the solid electrolyte forming a battery structure unit in the solid-state battery forms, for example, a layer capable of conducting lithium ions between the positive electrode layer and the negative electrode layer. As a specific solid electrolyte, for example, a lithium-containing phosphoric acid compound having a NASICON-type structure, an oxide having a perovskite-type structure, an oxide having a garnet-type or a garnet-like structure, an oxide glass ceramic lithium ion conductor, and the like can be listed. As the lithium-containing phosphoric acid compound having a NASICON-type structure, for example, Li 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). As an example of the lithium-containing phosphoric acid compound having a NASICON-type structure, for example, Li 1.2 Al 0.2 Ti 1.8 (PO4)3, and the like can be listed. As an example of the oxide having a perovskite-type structure, for example, La 0.55 Li 0.35 TiO3, and the like can be listed. As an example of the oxide having a garnet-type or a garnet-like structure, for example, Li7La3Zr2O 12 and the like can be listed. As the oxide glass ceramic lithium ion conductor, for example, a phosphoric acid compound containing lithium, aluminum, and titanium in the constituent elements (LATP), and a phosphoric acid compound containing lithium, aluminum, and germanium in the constituent elements (LAGP) can be used.

[0061] In addition, as a solid electrolyte capable of conducting sodium ions, for example, a sodium-containing phosphoric acid compound having a NASICON-type structure, an oxide having a perovskite-type structure, an oxide having a garnet-type or a garnet-like structure, and the like can be listed. As the sodium-containing phosphoric acid compound having a NASICON-type structure, for example, 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).

[0062] The solid electrolyte layer can contain a sintering aid. The sintering aid that can be contained in the solid electrolyte layer can be, for example, selected from the same materials as the sintering aid that can be contained in the positive electrode layer and / or the negative electrode layer.

[0063] (Positive electrode current collecting layer and negative electrode current collecting layer)

[0064] The positive electrode layer 1 and the negative electrode layer 2 may each have a positive current collector layer and a negative current collector layer, respectively. The positive and negative current collector layers may each have a foil-like form, but from the viewpoint of reducing the manufacturing cost and internal resistance of solid-state batteries through integral sintering, they may also have a sintered body form. It should be noted that when the positive and negative current collector layers have a sintered body form, they may also be composed of a sintered body containing conductive additives and sintering aids. The conductive additives that may be included in the positive and negative current collector layers may, for example, be selected from the same materials that may be included in the positive and / or negative electrode layers. The sintering aids that may be included in the positive and / or negative electrode current collector layers may, for example, be selected from the same materials that may be included in the positive and / or negative electrode layers. It should be noted that in solid-state batteries, the positive electrode current collector layer and / or the negative electrode current collector layer are not mandatory, and it is also possible to consider solid-state batteries without such positive electrode current collector layers and / or negative electrode current collector layers. That is, the solid-state battery in this invention can also be a "current collector-free" solid-state battery.

[0065] (external terminal)

[0066] Terminals for connecting to the outside (or an external device) (hereinafter referred to as "external terminals") can be provided on the solid-state battery stack 10. In particular, it is preferable to provide terminals for external connection as "end-face electrodes" on the side of the solid-state battery stack 10. More specifically, as external terminals, terminals (positive terminals) that can be electrically connected to the positive electrode layer 1 and terminals (negative terminals) that can be electrically connected to the negative electrode layer 2 can be provided (see, for example, [reference]). Figure 6 53A, 53B and Figure 7 (63A, 63B). Such terminals are preferably made of a material with high conductivity (or a conductive material). The material of the external terminal is not particularly limited, and can be selected from at least one of the group consisting of gold, silver, platinum, tin, nickel, copper, manganese, cobalt, iron, titanium and chromium.

[0067] [Features of the solid-state battery disclosed herein]

[0068] For example, such as Figure 1As illustrated, the solid-state battery (hereinafter, also referred to as "the solid-state battery of the present disclosure" or simply as "the solid-state battery" or "the battery") according to one embodiment of the present disclosure has, as a basic constituent element, a solid-state battery stack 10 (hereinafter, also referred to as "the battery main body") that has at least one battery structure unit 5 having a positive electrode layer 1, a negative electrode layer 2, and a solid electrolyte layer (or a solid electrolyte) 3 interposed between the positive electrode layer 1 and the negative electrode layer 2, along a stacking direction (or a thickness direction or a top-bottom direction). In addition, the solid-state battery of the present disclosure can have, for example, a positive electrode terminal and a negative electrode terminal as external terminals (more specifically, refer to Figure 6 the external terminals 53 (more specifically, the positive electrode terminal 53A and the negative electrode terminal 53B) of the embodiment illustrated in Figure 7 the external terminals 63 (more specifically, the positive electrode terminal 63A and the negative electrode terminal 63B)).

[0069] For example, as illustrated in Figure 2 the solid-state battery of the present disclosure preferably has an outer packaging member 11 that covers the battery main body. It is preferable that a gap 13 (more specifically, refer to Figure 6 the gap (53, 53') that can be included in the outer packaging member (51, 51') of the embodiment illustrated in

[0070] In the present disclosure, "the side of the inner side of the outer packaging member that is adjacent to the battery main body (or the solid-state battery stack)" basically refers to a portion or an area on the inner side or the inside of the outer packaging member that is geometrically close to or in contact with the battery main body or the interface (the interface of the outer packaging member and the battery main body).

[0071] In the present disclosure, "the side of the inner side of the outer packaging member that is adjacent to the battery main body (or the solid-state battery stack)" can include a portion of the outer packaging member that is in contact with the battery main body, a boundary or an interface of the outer packaging member and the battery main body, and other layers (for example, an intermediate layer or a mixed layer that can be formed during manufacturing, etc.) that can be formed between the outer packaging member and the battery main body.

[0072] In the present disclosure, "boundary" and "interface" basically refer to a geometric boundary of the outer packaging member and the battery main body. Such a boundary can also be included in "the side of the inner side of the outer packaging member that is adjacent to the battery main body (or the solid-state battery stack)".

[0073] For example, it is preferable that the gap 13 be present in the inner side region of the outer packaging member 11 (refer to Figure 2 ).

[0074] In the present disclosure, the "inner side region" refers to a region of the outer packaging member on a side close to the battery main body. More specifically, a region indicated by the height of reference sign H1 of FIG. 1 can be referred to as the "inner side region". Thus, in the present disclosure, a region of the outer packaging member on a side away from the battery main body can be referred to as the "outer side region". Figure 2

[0075] In the present disclosure, the "inner side region" can also include a portion of the outer packaging member in contact with the battery main body, a boundary or interface of the outer packaging member and the battery main body, and other layers (for example, an intermediate layer or a mixed layer, which can be formed during manufacturing, or the like) that can be formed between the outer packaging member and the battery main body.

[0076] With regard to "a gap exists on a side of the inner side of the outer packaging member that is adjacent to the battery main body (or the solid battery laminate)", and "a gap exists in the inner side region of the outer packaging member", for example, reference is made to Figure 9 for a simple explanation.

[0077] Figure 9 (A) of FIG. 1 schematically illustrates a typical case where a gap exists on the inner side of the outer packaging member. The shape of the gap can be irregular, regular, or geometric.

[0078] In the present disclosure, such a case can also be explained as "a gap exists on a side of the inner side of the outer packaging member that is adjacent to the battery main body (or the solid battery laminate)" or "a gap exists in the inner side region of the outer packaging member".

[0079] Figure 9 (B) of FIG. 1 schematically illustrates a typical case where a gap exists in a portion of the outer packaging member in contact with the battery main body. As Figure 9 indicated in (B) of FIG. 1, at least a portion of the gap can exist in contact with a boundary or interface of the outer packaging member and the battery main body.

[0080] In the present disclosure, such a case can also be explained as "a gap exists on a side of the inner side of the outer packaging member that is adjacent to the battery main body (or the solid battery laminate)" or "a gap exists in the inner side region of the outer packaging member".

[0081] Figure 9 (C) of FIG. 1 illustrates a case where a gap exists on the inner side of the outer packaging member. In addition, in (C) of FIG. 1, an intermediate layer or a mixed layer, which is an other layer that can be formed during manufacturing, is located between the outer packaging member and the battery main body. The thickness of the intermediate layer or the mixed layer or the like is not particularly limited. In Figure 9 (C) of FIG. 1, at least a portion of the gap exists in contact with a boundary or interface of the outer packaging member and the intermediate layer or the mixed layer. Figure 9

[0082] ​​In this disclosure, "intermediate or mixed layer that can be formed during manufacturing" refers to any layer that can be formed during manufacturing and can be located between the outer packaging component and the battery body (or solid battery laminate), or a layer that is a mixture of components or elements that may be contained in the outer packaging component and components or elements that may be contained in the battery body (or solid battery laminate).

[0083] In this disclosure, such a situation can also be interpreted as "a gap exists on the inner side of the outer packaging component adjacent to the battery body (or solid battery laminate)" or "a gap exists in the inner region of the outer packaging component".

[0084] Figure 9 (D) illustrates the presence of voids in an intermediate or hybrid layer that can be formed between the battery body and the outer packaging component. At least a portion of such voids may be in contact with the boundary or interface between the outer packaging component and the battery body.

[0085] In this disclosure, such a situation can also be interpreted as "a gap exists on the inner side of the outer packaging component adjacent to the battery body (or solid battery laminate)" or "a gap exists in the inner region of the outer packaging component".

[0086] The following is for reference Figure 2 The solid-state battery of this disclosure is further described in detail, particularly the “outer packaging component” capable of containing such voids, wherein in particular the “glass component”.

[0087] Figure 2 The outer packaging component 11 shown is a component capable of covering the periphery of the battery body; more specifically, it is a component capable of completely covering the periphery except for the left and right sides (or end faces) where the external terminals of the battery body are located (more specifically, see...). Figure 6 Outer packaging components (51, 51', etc.). It should be noted that, for example, such as Figure 2 As shown, the outer packaging component 11 is made of glass component 12 as a matrix or substrate, as detailed below, and functions as a cover layer for the battery body.

[0088] in addition, Figure 2 The outer packaging component 11 shown is disposed below it adjacent to or in contact with (e.g., in direct contact) a solid battery stack, i.e., the battery body (e.g., see reference). Figure 6 ).

[0089] For example, such as Figure 2 As shown, the main feature of the solid-state battery of this disclosure is that the battery body (e.g., inside the outer packaging component 11) is located on the inner side (or inside) of the outer packaging component 11. Figure 1 The inner region adjacent to the solid battery stack 10 (or interface) (e.g.,Figure 2 There is a gap 13 in the lower side of the outer packaging component 11 shown (more specifically, refer to...). Figure 8 For ease of explanation, the gap 13 is represented by the shape of a sphere with a circular cross-section, but the shape of the gap 13 is not necessarily limited to a sphere.

[0090] For example, such as Figure 2 As shown, since the gap 13 is biased towards the inner region of the outer packaging component 11, it acts as a buffer during charging and discharging of the solid-state battery, mitigating stress that may arise from the volume expansion or contraction of the battery body. Furthermore, it can suppress or prevent cracking or damage to the outer packaging component 11, thereby suppressing or preventing the intrusion of water vapor or moisture into the battery body. In other words, the gap 13 further enhances the gas barrier properties against water vapor and the like.

[0091] Furthermore, in the solid-state battery disclosed herein, preferably, for example, as shown in the example... Figure 2 As shown, the outer region of the outer packaging component 11, preferably the outer half (or upper half), has a relatively higher glass content 12 than the inner region, preferably the inner half (or lower half). This structure also prevents or inhibits the intrusion of water vapor or moisture into the battery body. Furthermore, it not only improves gas barrier properties but also enhances the strength, impact resistance, airtightness, and moisture resistance of the outer packaging component 11. The term "outer packaging component" and its components, such as "voids" and "glass content," will be described in more detail below.

[0092] (Outer packaging components)

[0093] In this disclosure, the "outer packaging component" is preferably able to completely cover the battery body of the solid-state battery (e.g., Figure 1 The solid-state battery laminate 10 shown refers, for example, to a cover layer or outer packaging layer comprising a "glass component" as a matrix or substrate, as described in the following detailed description. Such an outer packaging component is preferably composed of a sintered body comprising a glass component or the like.

[0094] In this disclosure, "glass composition" refers to a composition or material comprising glass as a main component (hereinafter sometimes referred to as "glass material"). There is no particular limitation on the glass material, but examples include at least one selected from the group consisting of silica glass (glass with silicon dioxide, silicon oxynitride, etc. as main components), soda-lime glass, potassium glass, borate glass, borosilicate glass, barium borosilicate glass, zinc borate glass, barium borate glass, bismuth borosilicate glass, zinc bismuth borosilicate glass, bismuth silicate glass, phosphate glass, aluminophosphate glass, and zinc phosphate glass.

[0095] In the present disclosure, "void" refers to one or more spaces, gaps, crevices, or cavities that can be formed inside the outer packaging member (particularly, a glass material).

[0096] The outer packaging member (particularly, a glass material) is generally airtight but hard and brittle.

[0097] However, by forming a void inside the outer packaging member (particularly, a glass material) in which gas barrier properties can be ensured while generation of cracks or defects and the like can be significantly suppressed as in the present disclosure.

[0098] The shape of the void is not particularly limited, in other words, can have an arbitrary shape, and the shape of the void can be regular or irregular in geometry. For example, as shown in Figure 2 , it can be spherical with a substantially circular cross-sectional shape, or it can be ellipsoidal or rugby ball-shaped, substantially triangular, substantially quadrangular, substantially polygonal, substantially cross-shaped, and / or substantially star-shaped, or a random shape (see Figure 9 ). Thus, in the outer packaging member (particularly, a glass material), a plurality of mutually different voids of mutually different shapes or sizes can be randomly mixed.

[0099] The shape of the void is desirably spherical with a circular cross-sectional shape. In addition, a shape close to the shape of a spherical void with a circular cross-sectional shape is preferred. From such a viewpoint, the circularity can be in the range of 0.1 to 1.0.

[0100] The size of the void is not particularly limited, and for example, as shown in Figure 2 , in the case where the shape of the cross section is substantially circular, the diameter or the maximum diameter thereof can be taken as the size of the void, and in the case where the void has a cross section of another shape, the diameter in the case where the calculation is converted to a circular shape can be taken as the size of the void.

[0101] The size of the void is, for example, in the range of 1 μm or more and 20 μm or less. In addition, the average size of the voids that can be contained in the outer packaging member (particularly, a glass material) is, for example, in the range of 3 μm or more and 20 μm or less.

[0102] Note that the size of such a void can be determined by image processing such as binarization from an electron microscope photograph of the cross section of the outer packaging member. The binarization will be described in detail below.

[0103] (Cross section)

[0104] More specifically, the cross section of the outer packaging member can be formed by the following method.

[0105] For example, the solid battery is fixed with a resin, and then cut to the vicinity of the observation surface. The cut surface is polished to the observation surface using sandpaper or the like.

[0106] The polishing method is not particularly limited, and rough polishing can be performed using coarse sandpaper, and then polishing can be performed using sandpaper or a polishing agent having a small abrasive grain size. In addition, an automatic polisher, sandpaper, ion milling, or chemical mechanical polishing (CMP) can be used in polishing. The polished surface is photographed using an electron microscope, binarized using image processing software, and the void ratio and / or the size of the voids can be calculated.

[0107] Note that the cut surface in the cross-sectional observation of the outer packaging member can be processed with any surface as the bottom surface, but is preferably processed vertically with respect to the bottom surface.

[0108] In addition, the cut surface can be processed as the proximal side at a position that is half the depth (for example, refer to Figure 10 ).

[0109] The exposure method of the cross section is not limited, but the cross section is preferably smooth, and for example, after the cross section is exposed by polishing after being embedded in a cured resin, the smooth observation cross section can be exposed by ion milling.

[0110] (Void)

[0111] The voids can be formed, for example, by using a void forming agent or the like when the outer packaging member is formed, or by intentionally reducing the amount of glass component.

[0112] In such a void, in the case where the outer packaging member is formed by firing together with each layer that can be included in the battery main body (that is, in the case where the battery main body is formed as an integral sintered body), a void that can be formed as a bubble inside the outer packaging member by gas (for example, O2, CO2, CO, or the like) that can be generated at the time of firing can be included.

[0113] As the void forming agent, for example, an organic substance can be used, and for example, a polymer (a polyolefin such as polyethylene and / or polypropylene, or the like, but this is only an example) can be used. For example, an organic substance such as an adhesive (for example, a polymer such as polypropylene, or the like) or the like can be vaporized at the time of firing, and thus a bubble can be formed inside the outer packaging member, and further, a void can be formed.

[0114] For example, in the case where the outer packaging member is formed by firing together with each layer that can be included in the battery main body (that is, in the case where the battery main body is formed as an integral sintered body), a void that can be formed as a bubble inside the outer packaging member by gas (for example, O2, CO2, CO, or the like) that can be generated at the time of firing can be included. Figure 2In the outer packaging member 11 shown, the voids 13 can exist in the inner side (or lower side) of the outer packaging member 11 that is adjacent to the battery main body (or interface). In other words, the voids 13 can exist in the inner side region of the outer packaging member 11 that is adjacent to the battery main body (or interface), preferably in the inner side half (or lower side half). The voids 13 can be in contact with the interface of the outer packaging member 11 and the battery main body. In addition, the cross-sectional shape of the voids is not necessarily limited to a circular shape.

[0115] More specifically, as shown schematically, it is preferable for the voids 13 to exist in a region in the thickness direction shown by a height H1 that is 50% or less, preferably 35% or less, relative to the height H0 in the thickness direction of the outer packaging member 11. Figure 2

[0116] In addition, in the solid-state battery of the present disclosure, it is preferable for the void ratio of the inner side region of the outer packaging member 11 that is adjacent to the battery main body (or interface), preferably the inner side half (or lower side half), to be greater than the void ratio of the outer side half (or upper side half), or for the voids 13 to be relatively more. In other words, in the outer packaging member 11, it is preferable for the voids 13 to be biased to exist in a region in the thickness direction shown by a height H1 that is 50% or less, relative to the height H0 in the thickness direction thereof. Thus, in the solid-state battery of the present disclosure, the voids 13 can also exist in the outer side region (preferably the outer side half (or upper side half)) of the outer packaging member 11, but it is preferable for the number, area, or volume of the voids 13 that exist in the inner side region, preferably the inner side half (or lower side half), to be greater than the number, area, or volume of the voids that exist in the outer side region.

[0117] The height H0 in the thickness direction of the outer packaging member 11 is, for example, 500 μm or less.

[0118] In this way, by having more voids exist in the inner side region that is adjacent to the battery main body (or interface) inside the outer packaging member 11, the expansion or contraction of the battery main body can be further moderated, and cracking or defects can be suppressed, further improving the gas barrier properties.

[0119] In addition, inside the outer packaging member 11, the voids 13 can be biased to exist in a region represented by a length L1 that is, for example, less than 100%, preferably 90% or less, relative to the length L0 of the outer packaging member 11 (i.e., the length in the direction perpendicular to the stacking direction of the solid-state battery stack) (i.e., from both end portions of the outer packaging member 11).

[0120] The voids 13 can exist in a proportion of, for example, 2% or more and 20% or less, preferably 3% or more and 15% or less, relative to the total area of the outer packaging member 11, in cross-sectional observation. Note that such a proportion can be determined by image processing such as binarization from an electron microscope photograph of the cross section of the outer packaging member.​

[0121] In the solid-state battery of the present disclosure, the outer packaging member is preferably a water vapor barrier film. That is, the outer packaging member covers the top surface, the bottom surface, and the front and back surfaces of the solid-state battery to preferably function as a barrier that prevents moisture from entering the solid-state battery. The "barrier" in the present specification broadly refers to a property of preventing water vapor from permeating to such an extent that the property deterioration of the solid-state battery due to water vapor from the outside environment passing through the outer packaging member does not occur, and narrowly refers to a water vapor permeation rate of less than 1.0 x 10 -3 g / (m 2 ·Day). Thus, in short, it can be said that the water vapor barrier film preferably has a water vapor permeation rate of 0 or more and less than 1.0 x 10 -3 g / (m 2 ·Day). Note that the "water vapor permeation rate" referred to herein refers to a permeation rate obtained under a measurement condition of 40°C, 90% RH, 1 atm of differential pressure using a gas permeation rate measuring device of Model GTms-1 manufactured by Advanced Industrial Science and Technology.

[0122] In particular, in the case of a NASICON-type structure, the solid-state battery preferably has a water vapor permeation rate of less than 1.0 x 10 -3 g / (m 2 ·Day).

[0123] The outer packaging member 11, particularly the glass component 12, for example, as shown in Figure 3 may further include an inorganic filler 24.

[0124] As the inorganic filler 24, there is no particular limitation, and at least one selected from the group consisting of various ceramics, such as oxides, nitrides, and carbides of alumina, silica, and zirconia, and the like can be exemplified. By adding such an inorganic filler, for example, the strength, impact resistance, air tightness, and / or moisture resistance, and the like can be further improved.

[0125] The inorganic filler 24 can be present in the outer packaging member 21 without being biased, or can be biased. The inorganic filler 24 can be uniformly dispersed. The inorganic filler 24 is present in a proportion of, for example, 10% or more and 90% or less with respect to the total area of the outer packaging member 21 under cross-sectional observation. Note that such a proportion can be determined by image processing such as binarization from an electron microscope photograph of the cross section of the outer packaging member.

[0126] Note that Figure 3 the outer packaging member 21, the glass component 22, the void 23, and the height H2 and the length L2 in the thickness direction shown in Figure 2The outer packaging member 11, the glass component 12, the void 13, and the height H1 and the length L1 in the thickness direction are shown.

[0127] In the solid-state battery of the present disclosure, the outer packaging member can have a "two-layer structure" composed of, for example, "a first outer packaging member" and "a second outer packaging member", or can have a structure of two or more layers (for example, an intermediate layer or a mixed layer that can be formed during manufacturing, a third outer packaging member, a fourth outer packaging member, a fifth outer packaging member, and the like).

[0128] In one mode, in the solid-state battery of the present disclosure, it is preferable that the outer packaging member has a structure of two or more layers.

[0129] For example, in Figure 4 In the embodiment shown above, the outer packaging member (for example, Figure 2 The outer packaging member 11 shown above) can have a two-layered manner in which it is separated into a first outer packaging member 31 and a second outer packaging member 35.

[0130] Note that, in Figure 4 In the embodiment shown above, it is possible to dispose, for example, a solid electrolyte layer 21, a positive electrode layer 22, and a negative electrode layer 23 below the first outer packaging member 31. Figure 1 The solid-state battery laminate 10 shown above, that is, the battery main body.

[0131] In Figure 4 In the embodiment shown above, it is preferable that the first outer packaging member 31 is disposed in contact with the battery main body (or the interface), the second outer packaging member 35 is disposed in contact with the side of the first outer packaging member 31 that is opposite to the battery main body, and the void 33 is present in the first outer packaging member 31. Note that, in the solid-state battery of the present disclosure, the void can also be present in the second outer packaging member 35, but it is preferable that the number or area or volume of the void is less than that of the void 33 contained in the first outer packaging member 31.

[0132] It is preferable that the first outer packaging member 31 and the second outer packaging member 35 each independently contain a glass component (or a glass material) (32, 36), and that the void 33 is present in the glass component 32 of the first outer packaging member 31. Note that, the void 33 included in the first outer packaging member 31 (specifically, the glass component 32) can correspond to the void 13 of Figure 2 , and with respect to the glass component (32, 36) that can be contained in the first outer packaging member 31 and the second outer packaging member 35, it is also possible to use the glass component described above independently (hereinafter, the glass component that can be contained in the first outer packaging member 31 will be referred to as "the first glass component 32", and the glass component that can be contained in the second outer packaging member 35 will be referred to as "the second glass component 36").

[0133] InFigure 4 In the first outer packaging member 31, the first glass component 32 is preferably present in a proportion of 10% or more and 60% or less, for example, with respect to the total area of the first outer packaging member 31, as viewed in cross section.

[0134] In Figure 4 In the embodiment shown, the thickness T1 of the first outer packaging member 31 is preferably greater than 50% of the overall thickness T of the outer packaging member. a ("thickness T1 of the first outer packaging member 31" + "thickness T2 of the second outer packaging member 35") is 50% or less.

[0135] In Figure 4 In the second outer packaging member 35, the second glass component 36 is present in a proportion of 100% or less, preferably 30% or more and 80% or less, for example, with respect to the total area of the second outer packaging member 35, as viewed in cross section.

[0136] In Figure 4 In the embodiment shown, the thickness T2 of the second outer packaging member 35 is preferably greater than 50% of the overall thickness T of the outer packaging member. a

[0137] The first outer packaging member 31 and the second outer packaging member 35 can each independently further contain the inorganic filler described above.

[0138] Each of the first outer packaging member 31 and the second outer packaging member 35 can contain an inorganic filler.

[0139] Alternatively, either of the first outer packaging member 31 and the second outer packaging member 35 can contain an inorganic filler.

[0140] For example, in Figure 5 In the embodiment shown, the first outer packaging member 41 can contain a first inorganic filler 44, and the second outer packaging member 45 can contain a second inorganic filler 47. The first inorganic filler 44 that can be contained in the first outer packaging member 41 and the second inorganic filler 47 that can be contained in the second outer packaging member 45 can be the same or different.

[0141] In Figure 5 In the embodiment shown, the first glass component 42 and the void 43 that can be contained in the first outer packaging member 41 can correspond to the first glass component 32 and the void 33, respectively, that can be contained in the first outer packaging member 31 shown. In addition, Figure 4 In the embodiment shown, the first glass component 32 and the void 33 that can be contained in the first outer packaging member 31 can correspond to the first glass component 42 and the void 43, respectively, that can be contained in the first outer packaging member 41 shown. Figure 5 In the embodiment shown, the second glass component 46 that can be contained in the second outer packaging member 45 can correspond to the second glass component 36 shown. Figure 4 In the embodiment shown, the second glass component 36 that can be contained in the second outer packaging member 35 can correspond to the second glass component 46 that can be contained in the second outer packaging member 45 shown.

[0142] In​Figure 5 In the illustrated embodiment, the proportion of the first glass component 42 in the first outer packaging member 41 is preferably 20% or less relative to the entire volume of the first outer packaging member 41. By having a glass component in such a proportion, a more sufficient amount of the voids 43 can be ensured in the first outer packaging member 41. Thus, the solid-state battery, when charged and discharged, the plurality of voids 43 become a buffer and can mitigate stress that can occur due to expansion or contraction of the volume of the battery body, and further can inhibit or prevent cracking or damage of the first outer packaging member 41. As a result, it is possible to inhibit or prevent the intrusion of water vapor or moisture into the battery body.

[0143] In Figure 5 In the illustrated embodiment, the proportion of the second glass component 46 in the second outer packaging member 45 is preferably 50% or more relative to the entire volume of the second outer packaging member 45. By having a glass component in such a proportion, a more sufficient amount of the glass component can be ensured in the second outer packaging member 45. Thus, in the second outer packaging member 45, the strength, impact resistance, airtightness, and / or moisture resistance, and the like can be improved.

[0144] For example, as Figure 5 As illustrated, by dividing the outer packaging member into at least two layers of the first outer packaging member 41 and the second outer packaging member 45, the roles of each layer can be clearly defined, respectively. Thus, in the solid-state battery of the present disclosure, the outer packaging member preferably has a two-layer structure or a structure of two or more layers.

[0145] Note that, in the outer packaging member of the present disclosure, in the case where the outer packaging member has a structure of two or more layers, the boundary thereof is not necessarily a straight line. In addition, depending on the kind of the glass component selected, for example, by using the same glass component, the boundary thereof can not be confirmed by the naked eye or a microscope or the like.

[0146] In the solid-state battery of the present disclosure, in the case where the outer packaging member is a sintered body, depending on the material selected, for example, by using a ceramic or the like as an inorganic filler, the boundary between the glass component and the inorganic filler can not be confirmed by the naked eye or a microscope or the like.

[0147] (One Preferred Embodiment)

[0148] Figure 6 The "solid-state battery 50" is shown in the above as a preferred embodiment of the solid-state battery of the present disclosure, but this is only one example. The solid-state battery 50 can have a solid-state battery stack (i.e., a battery body) that has, for example, at least one battery structure unit 5 along a stacking direction, the battery structure unit 5 having, for example, Figure 1The positive electrode layer 1, the negative electrode layer 2, and the solid electrolyte layer 3 interposed therebetween are shown. On the opposite left and right sides (or end faces) of such a battery main body, as external terminals 53, for example, a positive electrode terminal 53A and a negative electrode terminal 53B can be provided so as to be opposed to each other. The solid-state battery 50 is provided with an outer packaging member (51, 51') that covers the battery main body.

[0149] More specifically, in the solid-state battery 50, an outer packaging member (51, 51') that covers the periphery (upper and lower faces and front and rear faces) of the battery main body except for the left and right sides (or end faces) is provided. In the Figure 6 In the cross-sectional view shown, for example Figure 3 The outer packaging member 21 shown is disposed above and below the battery main body so as to be opposed to each other (for example, refer to Figure 6 The outer packaging member (51, 51') shown. In the illustrated embodiment, the external terminals (53A, 53B) are also disposed on the left and right sides (or end faces) of the outer packaging member (51, 51'), but the left and right sides of the outer packaging member (51, 51') can be covered by such external terminals or can not be covered.

[0150] A gap (53, 53') can exist on the side (for example, the inner side region, preferably the inner half) of the inner side of the outer packaging member (51, 51') that adjoins the battery main body (or the interface). Therefore, such a solid-state battery, at the time of charge and discharge, can moderate the stress that can occur due to the expansion or contraction of the volume of the battery main body through such a gap (53, 53'), and further can inhibit or prevent the breakage or damage of the outer packaging member (51, 51'). As a result, the intrusion of water vapor or moisture into the battery main body can be inhibited or prevented.

[0151] In addition, in the outer side region, preferably the outer half, of the outer packaging member (51, 51'), the proportion of the glass component (52, 52') becomes larger. Therefore, in the outer packaging member (51, 51'), the gas barrier property against water vapor and the like can be further improved.

[0152] Furthermore, since the inorganic filler (54, 54') can be contained in the inside of the outer packaging member (51, 51') that covers the battery main body, in the outer packaging member (51, 51'), the strength, impact resistance, airtightness, and / or moisture resistance, and the like can also be further improved.

[0153] Note that, in the solid-state battery 50, the outer packaging member (51, 51') can also be appropriately changed to Figure 2 The outer packaging member 11 shown.

[0154] Figure 7A "solid battery 60" is shown in FIG. 6 as another preferred embodiment of the solid battery of the present disclosure. The solid battery 60 can have a solid battery stack (i.e., a battery main body) that has, for example, at least one battery structure unit 5 having, for example Figure 1 the positive electrode layer 1, the negative electrode layer 2, and the solid electrolyte layer 3 therebetween. On the opposite left and right sides (or end faces) of such a battery main body, as external terminals 63, a positive electrode terminal 63A and a negative electrode terminal 63B can be provided so as to face each other. As an outer packaging member that covers the two-layer structure of the battery main body, the solid battery 60 has a first outer packaging member (61, 61') and a second outer packaging member (65, 65').

[0155] More specifically, in the solid battery 60, the first outer packaging member (61, 61') and the second outer packaging member (65, 65') that cover the periphery (upper and lower faces and front and rear faces) of the battery main body except for the left and right sides (or end faces) can be provided. In the cross-sectional view shown in FIG. 6, the first outer packaging member (61, 61') and the second outer packaging member (65, 65') are disposed so as to face each other on the upper and lower sides of the battery main body as a two-layer structure (see FIG. 6). Figure 7 Figure 5 In the cross-sectional view shown in FIG. 6, the first outer packaging member (61, 61') and the second outer packaging member (65, 65') are disposed so as to face each other on the upper and lower sides of the battery main body as a two-layer structure (see FIG. 6).

[0156] In the first outer packaging member (61, 61') that directly covers the battery main body, a gap (63, 63') can be present. Therefore, such a solid battery can alleviate stress that can be generated due to expansion or contraction of the volume of the battery main body at the time of charge and discharge through such a gap (63, 63'), and further can suppress or prevent breakage or damage of the first outer packaging member (61, 61'). As a result, it is possible to suppress or prevent the intrusion of water vapor or moisture into the battery main body.

[0157] In addition, the second outer packaging member (65, 65') has a larger proportion of glass components (66, 66') than the first outer packaging member (61, 61'). Therefore, in the second outer packaging member (65, 65'), the gas barrier property against water vapor and the like can be further improved.

[0158] ​Since the first outer packaging member (61, 61') and the second outer packaging member (65, 65') covering the battery main body can respectively include the first inorganic filler (64, 64') and the second inorganic filler (67, 67'), it is possible to further improve the strength, impact resistance, airtightness, and / or moisture resistance of the first outer packaging member (61, 61') and the second outer packaging member (65, 65'), particularly the second outer packaging member (65, 65').

[0159] Note that, in the solid-state battery 60, the first outer packaging member (61, 61') and the second outer packaging member (65, 65') can also be appropriately changed to the first outer packaging member 31 and the second outer packaging member 35 illustrated in FIG. 1. Figure 4

[0160] In addition, in the above-described embodiments, the heat insulating effect can be exerted by the voids included in the outer packaging member in any of the modes, and thus the solid-state battery can be used at a wide range of temperatures. For example, the solid-state battery of the present disclosure can withstand mounting of the solid-state battery on a substrate by reflow soldering or the like. Thus, the solid-state battery of the present disclosure can be used as a chip-type surface-mounted device (SMD).

[0161] In the above-described embodiments, the positive electrode layer 1 and the negative electrode layer 2 are preferably layers capable of intercalating and deintercalating lithium ions. By adopting such a structure, the secondary battery of the present disclosure can be used as a lithium ion secondary battery.

[0162] The solid-state battery of the present disclosure is not limited to the above-described embodiments. In addition, the solid-state battery of the present disclosure can be manufactured, for example, by a printing method such as a publicly known screen printing method or the like, a green sheet method using a green sheet, or a composite method thereof. However, the manufacturing method of the solid-state battery of the present disclosure is not limited to the above-described method.

[0163] (binarization)

[0164] For example, the binarization can be performed using an open source public domain image processing software, "Fiji imageJ" (https: / / imagej.net / Fiji).

[0165] For example, the photograph of the cross section under an electron microscope illustrated in FIG. 6 is binarized using the image processing software "Fiji imageJ", and the void ratio and the like are calculated. Figure 11

[0166] Note that, the void ratio of each of the "outer packaging member (outer side)" and the "outer packaging member (inner side)" can be, for example, as illustrated in FIG. 7, binarized by being divided into the "outer packaging member (outer side)" and the "outer packaging member (inner side)". Figure 12

[0167] ​​​The binarization can be performed as long as the voids can be recognized, and the conditions are not particularly limited. For example, in the image processing software "Fiji imageJ", the binarization can be performed in the default ("Default") automatic ("Auto") (see Figure 13 ).

[0168] In a case where the boundary between the "outer packaging member (inner side)" and the "battery main body (or solid battery laminate)" is not clear (for example, see (A) of Figure 14 ), the boundary can be made clear by a line of a white line or the like, for example, using a drawing function (see (B) of Figure 14 ). For example, the thickness of the line of the white line or the like can be set to the number of pixels of 1 μm or less. Note that in the present disclosure, such a line of the white line or the like can be interpreted as being included in the "outer packaging member (inner side)".

[0169] Regarding the binarization of the "outer packaging member (outer side)", see (C) of Figure 14 .

[0170] In order that the image can be appropriately analyzed in the image analysis after the binarization, it is preferable to previously acquire the image in such a manner that the object is parallel along the lateral (horizontal) direction.

[0171] The range is set so that the entire outer packaging member (outer side) enters, so that all the voids can be recognized in the outer packaging member (inner side), and the range is set so that the analysis area of the "outer packaging member (outer side)" and the "outer packaging member (inner side)" is the same.

[0172] For example, in order that the area of the "outer packaging member (outer side)" and the area of the "outer packaging member (inner side)" are the same, for example, the thickness of the outer packaging member is previously measured, and based on this, the analysis range is appropriately determined at the time of the designation of the range, for example, the length shown in the window of "imageJ" can be referred to.

[0173] For the designated range, by measuring the area of the voids, the "void ratio (%) " (or the void area ratio (%)) can be determined. Specifically, the void ratio (%) can also be determined by selecting "Analyze particles".

[0174] For example, it is preferable to determine the void ratio in the range where the area (size) of the voids is 0.785 to 400 μm 2 (corresponding to the circular diameter of 1 to 20 μm ("Circularity, circularity")) and the circularity is 0.1 to 1.0. In addition, it is also possible to convert the cross section of the voids into a circle to determine the diameter or the like based on these values.

[0175] In Figures 11 to 14The void ratio of the "outer packaging member (inner side)" was "3.793%" and the void ratio of the "outer packaging member (outer side)" was "1.511%" in the illustrated sample.

[0176] By such binarization, the ratio of the "void ratio of the outer packaging member (inner side)" to the "void ratio of the outer packaging member (outer side)" can be obtained.

[0177] The ratio of the "void ratio of the outer packaging member (inner side)" to the "void ratio of the outer packaging member (outer side)" is, for example, greater than 1.0, preferably 1.1 or more, and more preferably 2 or more and 10 or less. Note that the upper limit of the ratio can be, for example, 10, 9, 8, 7, 6, 5, 4, or 3, or the like.

[0178] For example, in the case where the "void ratio of the outer packaging member (inner side)" is 3.0 or more and 10 or less and the "void ratio of the outer packaging member (outer side)" is 1.0 or more and 10 or less, the ratio of the "void ratio of the outer packaging member (inner side)" to the "void ratio of the outer packaging member (outer side)" is, for example, 1.0 or more and 10 or less. Figures 11 to 14 The ratio of the "void ratio of the outer packaging member (inner side)" to the "void ratio of the outer packaging member (outer side)" was "2.5" in the illustrated sample.

[0179] In the outer packaging member (inner side), the voids can exist in a proportion of, for example, 2% or more and 20% or less, and preferably 4% or more and 20% or less, with respect to the total area of the outer packaging member (inner side) under cross-sectional observation (see Figure 4 ).

[0180] In the outer packaging member (outer side), in the case where the outer packaging member (outer side) contains voids, such voids can exist in a proportion of, for example, 2% or more and 20% or less, and preferably 2% or more and 10% or less, with respect to the total area of the outer packaging member (outer side) under cross-sectional observation (see Figure 4 ).

[0181] Hereinafter, the solid-state battery of the present disclosure will be described in more detail by way of examples. Note that the solid-state battery of the present disclosure is not limited to the description of the following examples.

[0182] Example

[0183] Example 1

[0184] A solid-state battery 60 of the illustrated embodiment was produced. Figure 7

[0185] (i) Preparation of the solid-state battery laminate

[0186] The solid-state battery laminate can be manufactured by a printing method such as a screen printing method, a green sheet method using a green sheet, or a composite method thereof. That is, the solid-state battery laminate can be produced in accordance with the conventional manufacturing method of a solid-state battery (therefore, the raw material substances described below, such as the solid electrolyte, the organic binder, the solvent, the arbitrary additive, the positive electrode active material, the negative electrode active material, and the like, can use substances used in the known manufacturing of a solid-state battery).​

[0187] (Formation of stacked blocks)

[0188] A slurry was prepared by mixing a solid electrolyte, an organic binder, a solvent, and any additives. Then, a sheet with a fired thickness of approximately 10 μm was obtained from the prepared slurry through sheet forming.

[0189] • A paste for the positive electrode is prepared by mixing the positive electrode active material, solid electrolyte, conductive additive, organic binder, solvent, and any additives. Similarly, a paste for the negative electrode is prepared by mixing the negative electrode active material, solid electrolyte, conductive additive, organic binder, solvent, and any additives.

[0190] • A paste for the positive electrode is printed on the sheet, and a current collector layer is also printed as needed. Similarly, a paste for the negative electrode is printed on the sheet, and a current collector layer is also printed as needed.

[0191] • A laminate is obtained by alternately stacking sheets printed with positive electrode paste and sheets printed with negative electrode paste.

[0192] It should be noted that the outermost layer (uppermost and / or lowermost layer) of the laminate can be an electrolyte layer, an insulating layer, or an electrode layer.

[0193] (Formation of battery sintered body)

[0194] After the laminates are pressed together, they are cut to the specified dimensions. The resulting cut laminates are then degreased and fired. This yields a sintered laminate.

[0195] It should be noted that the laminated body can also be degreased and fired before cutting.

[0196] (ii) Formation of external terminals

[0197] For example, Figure 7 As shown, silver (Ag) paste is applied to the entire surface of at least the left side (end face) and the entire surface of the right side (end face) of the solid battery stack, and then heated and cured on a heating plate at 200°C for 30 minutes to form external terminals (positive terminal 63A and negative terminal 63B) made of silver (Ag).

[0198] (iii) Formation of the characteristic part (outer packaging component) of the present invention

[0199] The following pastes are prepared for the first outer packaging component and the second outer packaging component.

[0200] Around the periphery of the block of the above-mentioned green sheet except for the side on which the external terminal is formed, the paste for the first external packaging member and the paste for the second external packaging member are laminated as green sheets in a two-layer structure, and are fired integrally with the solid battery laminate as described above.

[0201] • Paste for the first external packaging member

[0202] A paste containing a glass material, an inorganic filler, an organic binder, and a solvent was prepared.

[0203] Note that, for the paste for the first external packaging member, the ratio of the glass material and the inorganic filler was adjusted so that the volume ratio of the glass component / inorganic filler contained in the first external packaging member (61, 61') after firing is 20 / 80.

[0204] • Paste for the second external packaging member

[0205] A paste containing a glass material, an inorganic filler, an organic binder, and a solvent was prepared.

[0206] Note that, for the paste for the second external packaging member, the ratio of the glass material and the inorganic filler was adjusted so that the volume ratio of the glass component / inorganic filler contained in the second external packaging member (65, 65') after firing is 50 / 50.

[0207] In the solid battery 60 of Example 1, the voids (63, 63') included in the first external packaging member (61, 61') are formed from gas (O2, CO2, CO, etc.) generated from each layer of the laminate block at the time of integral sintering with the solid battery laminate.

[0208] Example 2

[0209] A solid battery was produced in the same manner as in Example 1 except that no inorganic filler was used in the paste for the first and second external packaging members, and the number of layers of the solid battery laminate was increased.

[0210] After fixing the solid battery with resin, the solid battery was cut to the vicinity of the observation surface (see Figure 10 ). Polishing of the cut surface to the observation surface was performed using sandpaper.

[0211] Specifically, after embedding the solid battery in the cured resin and polishing to expose the cross section, the cross section was formed by processing using ion milling to form a smooth observation cross section.

[0212] The cross section of the solid battery was photographed using an electron microscope (SEM) (see Figure 11(Reference scale: 10 pm), and binarized using image processing software ("Fiji imageJ" (https: / / imagej.net / Fiji)) (refer to Figure 14 ).

[0213] (Binarization)

[0214] The distance of each pixel ("Distance in pixels") was normalized based on the length of the scale of the electron micrograph (10 pm) ("Known Distance") and the unit of measurement (micrometers (pm)) ("Unit of Length").

[0215] The distance of each pixel ("Distance in pixels") was "33" ("Pixel aspect ratio" = 1.0).

[0216] Binarized into "Outer packaging member (outer side)" and "Outer packaging member (inner side)" (refer to Figure 12 ).

[0217] In the image processing software "Fiji imageJ", binarization was performed using the default ("Default") automatic ("Auto") (refer to Figure 13 and Figure 14 ).

[0218] The boundary between "Outer packaging member (inner side)" and "Battery main body (or solid-state battery laminate)" was clarified by a white line (the number of pixels below 1 pm) (refer to Figure 14 (B)). Such a white line is interpreted as being included in the "Outer packaging member (inner side)".

[0219] Regarding the binarization of "Outer packaging member (outer side)", refer to Figure 14 (C).

[0220] Regarding the range of image analysis, the range was set so that the analysis area of "Outer packaging member (outer side)" and "Outer packaging member (inner side)" was the same.

[0221] Regarding the specified range, by measuring the area of the void, the "void ratio (%) " (or void area ratio (%)) was determined (the area of the void was 0.785-400 pm 2 (corresponding to a circular diameter of 1-20 pm ("Circularity")), in the range of 0.1-1.0).

[0222] The void ratio of the “outer packaging component (inner side)” is “3.793%”, and the void ratio of the “outer packaging component (outer side)” is “1.511%”.

[0223] The ratio of "void ratio of outer packaging component (inner side)" to "void ratio of outer packaging component (outer side)" is "2.5".

[0224] As described above, it has been confirmed that in the solid-state battery produced in Example 2, the "porosity of the outer packaging component (inner side)" is greater than the "porosity of the outer packaging component (outer side)".

[0225] The above description, through various embodiments and examples, illustrates the solid-state battery of this disclosure, but these are merely typical examples. Therefore, those skilled in the art will readily understand that this disclosure is not limited thereto, and various embodiments can be conceived.

[0226] (Method 1)

[0227] A solid-state battery,

[0228] The solid-state battery is formed by a solid-state battery stack, which has at least one battery structural unit. The battery structural unit has a positive electrode layer, a negative electrode layer, and a solid electrolyte layer between the positive electrode layer and the negative electrode layer.

[0229] The solid-state battery has external terminals respectively disposed on opposite sides of the solid-state battery stack.

[0230] The solid-state battery further comprises an outer packaging component covering the solid-state battery stack, and a gap exists on the inner side of the outer packaging component adjacent to the solid-state battery stack (or interface).

[0231] (Method 2)

[0232] The solid-state battery according to method 1

[0233] The gap exists in a proportion of more than 2% and less than 20% of the total area of ​​the outer packaging component when viewed in cross-section.

[0234] (Method 3)

[0235] Solid-state batteries according to method 1 or 2

[0236] The void exists in the inner region of the outer packaging component adjacent to the solid battery stack (or interface).

[0237] (Method 4)

[0238] The solid-state battery according to method 3

[0239] The porosity of the inner side region of the outer packaging member that is adjacent to the solid battery laminate (or interface) is greater than the porosity of the outer side region.

[0240] (Manner 5)

[0241] The solid battery according to any one of Manners 1 to 4,

[0242] The outer packaging member is composed of a glass component in which the voids are present.

[0243] (Manner 6)

[0244] The solid battery according to Manner 5,

[0245] The outer packaging member is further composed of an inorganic filler.

[0246] (Manner 7)

[0247] A solid battery,

[0248] The solid battery has a solid battery laminate composed of at least one battery structure unit that has a positive electrode layer, a negative electrode layer, and a solid electrolyte layer interposed between the positive electrode layer and the negative electrode layer,

[0249] The solid battery has external terminals respectively provided on opposite side surfaces of the solid battery laminate,

[0250] The solid battery further has an outer packaging member that covers the solid battery laminate,

[0251] The outer packaging member has a two-layer structure or a structure of two or more layers composed of a first outer packaging member that is provided adjacent to the solid battery laminate (or interface) and a second outer packaging member that is provided adjacent to a side of the first outer packaging member that is opposite to the solid battery laminate, and the voids are present in the first outer packaging member.

[0252] (Manner 8)

[0253] The solid battery according to Manner 7,

[0254] The voids are present in a proportion of 2% or more and 20% or less relative to the total area of the first outer packaging member in cross-sectional observation.

[0255] (Manner 9)

[0256] The solid battery according to Manner 7 or 8,

[0257] The second outer packaging member also includes voids, and a ratio of a void ratio in the first outer packaging member with respect to a total area of the first outer packaging member / the void ratio in the second outer packaging member with respect to a total area of the second outer packaging member is 1.1 or more when viewed in cross section.

[0258] (Manner 10)

[0259] The solid-state battery according to Manner 7,

[0260] The outer packaging member has a structure of two or more layers.

[0261] (Manner 11)

[0262] The solid-state battery according to Manner 7,

[0263] The first outer packaging member and the second outer packaging member each include a glass component, and the voids are present in the glass component of the first outer packaging member.

[0264] (Manner 12)

[0265] The solid-state battery according to Manner 5 or 11,

[0266] The glass component is at least one selected from the group consisting of silica glass, soda-lime glass, potash glass, borate-based glass, borosilicate-based glass, barium borosilicate-based glass, zinc borate-based glass, barium borate-based glass, bismuth borosilicate-based glass, bismuth zinc borate-based glass, bismuth silicate-based glass, phosphate-based glass, aluminum phosphate-based glass, and zinc phosphate-based glass.

[0267] (Manner 13)

[0268] The solid-state battery according to Manner 11 or 12,

[0269] The first outer packaging member and / or the second outer packaging member further include an inorganic filler.

[0270] (Manner 14)

[0271] The solid-state battery according to Manner 11 or 12,

[0272] Either of the first outer packaging member and the second outer packaging member includes an inorganic filler.

[0273] (Manner 15)

[0274] The solid-state battery according to any one of Manners 1 to 14,

[0275] The water vapor permeability is less than 1.0 x 10 -3 g / (m 2• Day).

[0276] (Aspect 16)

[0277] The solid-state battery according to any one of Aspects 1 to 15,

[0278] The positive electrode layer and the negative electrode layer are layers capable of intercalating and deintercalating lithium ions.

[0279] Industrial applicability

[0280] The solid-state battery of the present application can be applied to various fields that envisage the use of batteries or electric power storage. Although only examples, the solid-state battery of the present application can be applied to the following fields: the electric, information, and communication fields using electric and electronic equipment and the like (for example, the electric and electronic equipment field or the mobile device field including small electronic devices such as mobile phones, smartphones, notebook computers, and digital cameras, activity meters, ARM computers, electronic paper, wearable devices, RFID tags, card-type electronic money, smartwatches, and the like); household and small industrial uses (for example, the field of power tools, golf carts, household, nursing, and industrial robots); large industrial uses (for example, the field of forklifts, elevators, and port cranes); transportation system fields (for example, the field of hybrid cars, electric cars, buses, electric trains, electric assist bicycles, electric motorcycles, and the like); electric power system uses (for example, the field of various power generation, load regulators, smart grids, general household setting-type power storage systems, and the like); medical uses (the field of medical devices such as earphone hearing aids); pharmaceutical uses (the field of medication management systems and the like); and the IoT field; space and deep sea uses (for example, the field of space probes, submersible survey ships, and the like); and the like.

[0281] Explanation of reference numerals

[0282] 1, 101: positive electrode layer; 2, 102: negative electrode layer; 3, 103: solid electrolyte layer (or solid electrolyte); 5, 105: battery structure unit; 10: solid-state battery laminate (or battery main body); 11, 21, 51: outer packaging member; 12, 22, 52: glass component; 13, 23, 33, 43, 53, 63: void; 24, 54: inorganic filler; 31, 41, 61: first outer packaging member; 32, 42, 62: first glass component; 35, 45, 65: second outer packaging member; 36, 46, 66: second glass component; 44, 64: first inorganic filler; 47, 67: second inorganic filler; 50, 60: solid-state battery; 100: existing solid-state battery; 110: waterproof layer; 120: resin layer; 53, 63, 130: external terminal; 53A, 63A, 130A: positive electrode terminal; 53B, 63B, 130B: negative electrode terminal.

Claims

1. A solid-state battery, The solid-state battery is formed by a solid-state battery stack, which has at least one battery structural unit. The battery structural unit has a positive electrode layer, a negative electrode layer, and a solid electrolyte layer between the positive electrode layer and the negative electrode layer. The solid-state battery has external terminals respectively disposed on opposite sides of the solid-state battery stack. The solid-state battery further includes an outer packaging component that covers the solid-state battery stack. There is a void in the inner region of the outer packaging component adjacent to the solid-state battery stack, and the void ratio of the inner region is larger than that of the outer region of the outer packaging component.

2. The solid-state battery according to claim 1, wherein, The gap exists in a proportion of more than 2% and less than 20% of the total area of ​​the outer packaging component when viewed in cross-section.

3. The solid-state battery according to claim 1, wherein, The outer packaging component is made of glass, and the voids are present in the glass.

4. The solid-state battery according to claim 3, wherein, The outer packaging component further comprises inorganic fillers.

5. A solid-state battery, The solid-state battery is formed by a solid-state battery stack, which has at least one battery structural unit. The battery structural unit has a positive electrode layer, a negative electrode layer, and a solid electrolyte layer between the positive electrode layer and the negative electrode layer. The solid-state battery has external terminals respectively disposed on opposite sides of the solid-state battery stack. The solid-state battery further includes an outer packaging component that covers the solid-state battery stack. The outer packaging component has a two-layer structure or a structure with more than two layers, including a first outer packaging component and a second outer packaging component. The first outer packaging component is disposed adjacent to the solid-state battery stack, and the second outer packaging component is disposed adjacent to the side of the first outer packaging component opposite to the solid-state battery stack. There are gaps in the first outer packaging component, and the porosity of the first outer packaging component is greater than that of the second outer packaging component.

6. The solid-state battery according to claim 5, wherein, The gap exists in a proportion of more than 2% and less than 20% of the total area of ​​the first outer packaging component when viewed in cross-section.

7. The solid-state battery according to claim 5 or 6, wherein, The second outer packaging component also includes voids, and in cross-sectional view, the ratio of the void ratio in the first outer packaging component relative to the total area of ​​the first outer packaging component to the void ratio in the second outer packaging component relative to the total area of ​​the second outer packaging component is 1.1 or more.

8. The solid-state battery according to claim 5, wherein, The outer packaging component has a structure with more than two layers.

9. The solid-state battery according to claim 5, wherein, The first outer packaging component and the second outer packaging component are each made of glass, and the voids exist in the glass component of the first outer packaging component.

10. The solid-state battery according to claim 3 or 9, wherein, The glass composition is selected from at least one of the following groups: soda-lime glass, potassium glass, borosilicate glass, barium borosilicate glass, zinc borosilicate glass, barium borosilicate glass, bismuth borosilicate glass, zinc bismuth borosilicate glass, bismuth silicate glass, aluminophosphate glass, and zinc phosphate glass.

11. The solid-state battery according to claim 9, wherein, Each of the first outer packaging component and the second outer packaging component further comprises inorganic filler.

12. The solid-state battery according to claim 9, wherein, Either the first outer packaging component or the second outer packaging component contains inorganic filler.

13. The solid-state battery according to claim 1 or 5, wherein, Water vapor transmission rate is less than 1.0 × 10⁻⁶ -3 g / (m 2 Day).

14. The solid-state battery according to claim 1 or 5, wherein, The positive electrode layer and the negative electrode layer are layers capable of inserting and de-inserting lithium ions.

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