Solid state battery

Abstract

Provided is a solid-state battery. The solid-state battery is formed by comprising a solid-state battery laminate provided with at least one battery constituent 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. The solid-state battery is provided with external terminals of a positive electrode terminal and a negative electrode terminal that are provided on opposite lateral surfaces of the solid-state battery laminate. At least one electrode layer of the positive electrode layer and the negative electrode layer is configured such that an active material portion and an insulation portion of the electrode layer are laminated on each other in a boundary region between the electrode layer and the external terminal. In a cross-sectional view, the insulation portion covers the active material portion in a sleeve shape.

Description

[Technical field]

[0001] The present invention relates to a solid-state battery, and more specifically to a solid-state battery in which an insulating portion is laminated on an electrode layer in a boundary region between the electrode layer and an external terminal of the solid-state battery. [Background technology]

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

[0003] In secondary batteries, liquid electrolytes are generally used as a medium for ion migration that contributes to charging and discharging. In other words, so-called "electrolyte" is used in secondary batteries. However, in such secondary batteries, safety is generally required in terms of preventing leakage of the electrolyte. In addition, organic solvents and the like used in the electrolyte are flammable substances, so safety is also required in that 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] JP 2019-87347 A Summary of the Invention [Problem to be solved by the invention]

[0006] The inventors of the present application realized that conventional solid-state batteries have problems to be overcome and found it necessary to take measures to address these problems. Specifically, the inventors of the present application found the following problems:

[0007] 12, for example, a conventional solid-state battery 100 has a solid-state battery stack 150 including at least one battery unit along the stacking direction, the battery unit including a positive electrode layer 110, a negative electrode layer 120, and at least a solid electrolyte layer 130 interposed therebetween. The solid-state battery 100 further includes a positive electrode terminal 160A and a negative electrode terminal 160B provided on opposing side or end faces (more specifically, the left and right side or end faces) of the solid-state battery stack 150 as external terminals. The positive electrode terminal 160A is electrically connected to the positive electrode layer 110, and the negative electrode terminal 160B is electrically connected to the negative electrode layer 120.

[0008] For example, as shown in FIG. 12, in a conventional solid-state battery 100, insulating portions (also called electrode separators or blank layers) 140 can be provided between the positive electrode layer 110 and the negative electrode terminal 160B, and between the negative electrode layer 120 and the positive electrode terminal 160A, in order to prevent electrical short circuits.

[0009] Here, since it is generally desirable that each layer of a solid-state battery can be formed by firing, and thus that the solid-state battery stack form an integral sintered body, it is desirable to manufacture the solid-state battery stack by a lamination technique such as a printing method such as a screen printing method or a green sheet method using a green sheet.

[0010] However, the inventors' research has revealed that such lamination techniques, particularly manufacturing methods for solid-state batteries that utilize printing methods, tend to cause problems such as the following (1) to (3) in the lamination stages of each layer, i.e., in the lamination of the "positive electrode layer," the "negative electrode layer," and the "solid electrolyte layer," and in the formation of the "insulating portion" (see also FIG. 12).

[0011] (1) Short circuit between electrode layers In the vicinity of the insulating portion, when the positive electrode layer 110 is formed by a printing method or the like, the positive electrode layer 110 (specifically, the paste for forming the positive electrode layer 110) bulges or rises up, and is likely to be electrically short-circuited in proximity to the negative electrode layer 120 that may be formed at a position above in the stacking direction. Similarly, when the negative electrode layer 120 is formed by a printing method or the like, the negative electrode layer 120 (specifically, the paste for forming the negative electrode layer 120) bulges or rises up, and is likely to be electrically short-circuited in proximity to the positive electrode layer 110 that may be formed at a position above in the stacking direction. (2) Short circuit between electrode layer and external terminal In the vicinity of the insulating portion, when the positive electrode layer 110 is formed by a printing method or the like, the positive electrode layer 110 (specifically, the paste for forming the positive electrode layer 110) extends toward the negative electrode terminal 160B and approaches the negative electrode terminal 160B, easily causing an electrical short circuit. Similarly, when the negative electrode layer 120 is formed by a printing method or the like, the negative electrode layer 120 (specifically, the paste for forming the negative electrode layer 120) extends toward the positive electrode terminal 160A and approaches the positive electrode terminal 160A, easily causing an electrical short circuit. (3) Peeling of the electrode layer Due to its structure, physical peeling, particularly interlayer peeling, of the positive electrode layer 110 is likely to occur near the insulating part during the manufacture of the solid-state battery and during charging and discharging of the solid-state battery. Similarly, physical peeling, particularly interlayer peeling, of the negative electrode layer 120 is likely to occur near the insulating part.

[0012] All of the above problems are believed to result in a decrease in the performance of solid-state batteries.

[0013] Furthermore, the inventors' research has revealed that the above problem becomes particularly pronounced when the electrode layers are multi-layered, for example, by disposing a current collecting layer (more specifically, positive electrode current collecting layer 211, etc.) within the electrode layer, as shown in FIG. 13.

[0014] The present invention has been made in view of the above problems. That is, a main object of the present invention is to provide a solid-state battery in which short circuits between electrode layers, between an electrode layer and an external terminal, and peeling of the electrode layer are further suppressed. [Means for solving the problem]

[0015] The inventors of the present application attempted to solve the above problems by taking a new approach, rather than simply extending the conventional technology, and as a result, they have invented a solid-state battery that achieves the above-mentioned main object.

[0016] The present invention provides a solid-state battery comprising a solid-state battery stack including at least one battery constituent unit, for example along a stacking direction, the battery constituent unit including a positive electrode layer, a negative electrode layer, and a solid electrolyte layer interposed between the positive electrode layer and the negative electrode layer, and external terminals for a positive electrode terminal and a negative electrode terminal provided on opposing side surfaces (more specifically, on the left and right side surfaces in the illustrated embodiment) of the solid-state battery stack, and at least one of the electrode layers of the positive electrode layer and the negative electrode layer has a configuration in which an active material portion of the electrode layer and an insulating portion are stacked on each other in a boundary region with the external terminal, and the insulating portion covers the active material portion in a sleeve-like shape in a cross-sectional view.

[0017] For example, as shown in Fig. 1, in a solid-state battery according to one embodiment of the present invention, the electrode layers (1, 2) have a configuration in which an active material portion (1', 2') that can be included in at least one of the electrode layers (1, 2) and an insulating portion 4 or a part thereof are laminated together in a boundary region X with an external terminal 6, and the insulating portion 4 covers the active material portion (1', 2') in a "sleeve-like" manner in a cross-sectional view. In other words, in at least one of the electrode layers (1, 2), the insulating portion 4, particularly its "sleeve-like" portion (S), is vertically overlapped with the electrode layer (1, 2), particularly the active material portion (1', 2'), and is particularly in contact with the main surface of the electrode layer (1, 2), particularly the main surface of the active material portion (1', 2'), so that the insulating portion 4 can be disposed on the outside of the lamination direction of the electrode layers (1, 2) or in the vertical direction. Effect of the Invention

[0018] In the present invention, a solid-state battery is obtained in which short circuits between electrode layers, short circuits between electrode layers and external terminals, and peeling of the electrode layers are further suppressed. Note that the effects described in this specification are merely examples and are not limiting, and additional effects may also be provided. [Brief description of the drawings]

[0019] [Figure 1] FIG. 1 is a schematic cross-sectional view showing a boundary region of a solid-state battery according to one embodiment of the present invention. [Diagram 2] FIG. 2 is a schematic cross-sectional view showing a solid-state battery according to a first embodiment of the present invention. [Diagram 3] FIG. 3 is a schematic cross-sectional view showing a boundary region of the solid-state battery according to the first embodiment of the present invention. [Figure 4] FIG. 4 is a schematic cross-sectional view showing a solid-state battery according to a second embodiment of the present invention. [Diagram 5] FIG. 5 is a schematic cross-sectional view showing a boundary region of a solid-state battery according to a second embodiment of the present invention. [Figure 6] FIG. 6 is a schematic cross-sectional view showing a solid-state battery according to a third embodiment of the present invention. [Figure 7] FIG. 7 is a schematic cross-sectional view showing a boundary region of a solid-state battery according to a third embodiment of the present invention. [Figure 8] FIG. 8 is a schematic cross-sectional view showing a solid-state battery according to a fourth embodiment of the present invention. [Figure 9] FIG. 9 is a schematic cross-sectional view showing a boundary region of a solid-state battery according to a fourth embodiment of the present invention. [Figure 10] FIG. 10 is a schematic diagram showing the formation of the insulating portion. [Figure 11] FIG. 11 is a schematic diagram showing the formation of another insulating portion. [Figure 12] FIG. 12 is a schematic cross-sectional view showing a conventional solid-state battery. [Figure 13] FIG. 13 is a schematic cross-sectional view showing another conventional solid-state battery. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] The "solid-state battery" of the present invention will be described in detail below. Although the description will be made with reference to the drawings as necessary, the contents shown in the drawings are merely shown as schematic examples for understanding the present invention, and the appearance and / or dimensional ratios may differ from the actual product.

[0021] In this specification, the term "cross-sectional view" refers to the shape of the solid-state battery when viewed from a direction substantially perpendicular to the thickness direction based on the stacking direction or the stacking direction of each layer. In other words, it refers to the shape of the solid-state battery when cut along a plane parallel to the thickness direction. In short, it refers to the shape of the cross section of the object shown in, for example, Figures 1 and 2. The "upper and lower directions" and "left and right directions" used directly or indirectly in this specification correspond to the upper and lower directions and left and right directions in the drawings, respectively. Unless otherwise specified, the same symbols or symbols indicate the same members or parts or the same meanings. In a preferred embodiment, the vertical downward direction (i.e., the direction in which gravity acts) corresponds to the "lower direction" / "bottom side", and the opposite direction corresponds to the "upper direction" / "top side".

[0022] In the present invention, the term "solid-state battery" refers in a broad sense to a battery whose components may be made of solids, and in a narrow sense to an all-solid-state battery whose components (particularly preferably all components) may be made of solids. In a preferred embodiment, the solid-state battery of the present invention is a laminated solid-state battery in which each layer constituting a battery unit is laminated on top of each other, and preferably each such layer is made of a sintered body. The term "solid-state battery" may include not only so-called "secondary batteries" capable of repeated charging and discharging, but also "primary batteries" capable of only discharging. According to a preferred embodiment of the present invention, the "solid-state battery" is a secondary battery. The term "secondary battery" is not limited to being overly confined to the name, and may also include, for example, a power storage device.

[0023] In the following, first, the basic structure of the "solid-state battery" of the present invention will be described, and then the features of the solid-state battery of the present invention (particularly the "insulating portion") will be described. The basic structure of the solid-state battery described here is merely an example for understanding the invention, and does not limit the invention.

[0024] [Basic structure of solid-state batteries] A solid-state battery includes at least positive and negative electrode layers and a solid electrolyte layer (or solid electrolyte). More specifically, as shown in Fig. 2, the solid-state battery includes a solid-state battery stack (5) including at least one battery unit along the stacking direction, the battery unit including a positive electrode layer (1), a negative electrode layer (2), and at least a solid electrolyte layer (or solid electrolyte) (3) interposed therebetween.

[0025] Preferably, the solid-state battery may be formed by firing each of its constituent layers, and the positive electrode layer, the negative electrode layer, the solid electrolyte layer, etc. may form sintered layers. More preferably, the positive electrode layer, the negative electrode layer, and the solid electrolyte layer are each fired together, and therefore the battery constituent unit or the solid-state battery laminate may form an integral sintered body.

[0026] The positive electrode layer (1) is an electrode layer comprising at least a positive electrode active material. Thus, the positive electrode layer (1) may be a positive electrode active material layer mainly composed of a positive electrode active material. The positive electrode layer may further comprise a solid electrolyte, if necessary. In one embodiment, the positive electrode layer may be composed of a sintered body comprising at least positive electrode active material particles and solid electrolyte particles. The negative electrode layer (2) is an electrode layer comprising at least a negative electrode active material. Thus, the negative electrode layer (2) may be a negative electrode active material layer mainly composed of a negative electrode active material. The negative electrode layer may further comprise a solid electrolyte, if necessary. In one embodiment, the negative electrode layer may be composed of a sintered body comprising at least negative electrode active material particles and solid electrolyte particles.

[0027] The positive electrode active material and the negative electrode active material are materials that can participate in the absorption and release of ions and the transfer of electrons to and from an external circuit in a solid-state battery. Ions move (conduct) between the positive electrode layer and the negative electrode layer via the solid electrolyte. The absorption and release of ions in the active material is accompanied by the oxidation or reduction of the active material, and charge and discharge can proceed by transferring electrons or holes for such an oxidation-reduction reaction from the external circuit to an external terminal, and further to the positive electrode layer or the negative electrode layer. The positive electrode layer and the negative electrode layer can be formed by, for example, lithium ions, sodium ions, protons (H + ), potassium ion (K + ), magnesium ion (Mg 2+ ), aluminum ion (Al 3+ ), silver ions (Ag + ), fluoride ion (F - ) or chloride ion (Cl - In other words, the solid-state battery is preferably an all-solid-state secondary battery in which the ions move between the positive electrode layer and the negative electrode layer via the solid electrolyte to charge and discharge the battery.

[0028] (Cathode active material) The positive electrode active material that can be contained in the positive electrode layer (1) may be, for example, at least one selected from the group consisting of a lithium-containing phosphate compound having a Nasicon structure, a lithium-containing phosphate compound having an olivine structure, a lithium-containing layered oxide, and a lithium-containing oxide having a spinel structure. An example of a lithium-containing phosphate compound having a Nasicon structure is Li3V2(PO4)3. An example of a lithium-containing phosphate compound having an olivine structure is Li3Fe2(PO4)3, LiFePO4, LiMnPO4, and / or LiFe 0.6 Mn 0.4 Examples of lithium-containing layered oxides include LiCoO2, LiCo 1 / 3 Ni 1 / 3 Mn 1 / 3 O2, and / or LiCo 0.8 Ni 0.15 Al 0.05Examples of lithium-containing oxides having a spinel structure include LiMn2O4 and / or LiNi 0.5 Mn 1.5 Examples include O4.

[0029] In addition, examples of positive electrode active materials capable of absorbing and releasing sodium ions include 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.

[0030] (Negative electrode active material) Examples of the negative electrode active material that can be included in the negative electrode layer (2) include at least one selected from the group consisting of oxides containing at least one element selected from the group consisting of Ti, Si, Sn, Cr, Fe, Nb, and Mo, carbon materials such as graphite, graphite-lithium compounds, lithium alloys, lithium-containing phosphate compounds having a Nasicon structure, lithium-containing phosphate compounds having an olivine structure, and lithium-containing oxides having a spinel structure. An example of a lithium alloy is Li-Al. An example of a lithium-containing phosphate compound having a Nasicon structure is Li3V2(PO4)3 and / or LiTi2(PO4)3. An example of a lithium-containing phosphate compound having an olivine structure is Li3Fe2(PO4)3 and / or LiCuPO4. An example of a lithium-containing oxide having a spinel structure is Li4Ti5O 12 etc.

[0031] In addition, examples of negative electrode active materials capable of absorbing and releasing sodium ions include 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.

[0032] In addition, in the solid-state battery, the positive electrode layer and the negative electrode layer may be made of the same material.

[0033] The positive electrode layer and / or the negative electrode layer may contain a conductive material. Examples of the conductive material that may be contained in the positive electrode layer and the negative electrode layer include at least one selected from the group consisting of metal materials such as silver, palladium, gold, platinum, aluminum, copper, and nickel, and carbon.

[0034] Furthermore, the positive electrode layer and / or the negative electrode layer 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.

[0035] The thickness of the positive electrode layer and the negative electrode layer is not particularly limited. For example, the thickness of each of the positive electrode layer and the negative electrode layer may be 2 μm or more and 100 μm or less, and in particular, 5 μm or more and 50 μm or less.

[0036] (solid electrolyte) The solid electrolyte (or solid electrolyte layer) (3) is a material capable of conducting ions such as lithium ions or sodium ions. In particular, the solid electrolyte constituting the battery building blocks of a solid-state battery may form, for example, a layer capable of conducting lithium ions between the positive electrode layer and the negative electrode layer. Specific solid electrolytes include, for example, lithium-containing phosphate compounds having a Nasicon structure, oxides having a perovskite structure, oxides having a garnet or garnet-like structure, oxide glass ceramics-based lithium ion conductors, and the like. 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 Ti, Ge, Al, Ga and Zr). An example of a lithium-containing phosphate compound having a Nasicon structure is Li 1.2 Al 0.2 Ti 1.8 (PO4)3, etc. An example of an oxide having a perovskite structure is La0.55 Li 0.35 An example of an oxide having a garnet-type or garnet-like structure is Li7La3Zr2O 12 etc. As the oxide glass ceramic-based lithium ion conductor, 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. Examples of the solid electrolyte capable of conducting sodium ions include sodium-containing phosphate compounds having a Nasicon structure, oxides having a perovskite structure, and oxides having a garnet structure or a garnet-like structure. Examples of the 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).

[0037] The solid electrolyte layer may contain a sintering aid. The sintering aid that may be contained in the solid electrolyte layer may be selected from the same materials as the sintering aids that may be contained in the positive electrode layer and / or the negative electrode layer, for example.

[0038] The thickness of the solid electrolyte layer is not particularly limited and may be, for example, from 1 μm to 15 μm, in particular from 1 μm to 5 μm.

[0039] (Positive and negative electrode current collecting layers) The positive electrode layer (1) and the negative electrode layer (2) may each have a positive electrode current collecting layer and a negative electrode current collecting layer. The positive electrode current collecting layer and the negative electrode current collecting layer may each have the form of a foil. However, from the viewpoint of reducing the manufacturing cost of the solid battery by co-firing and reducing the internal resistance of the solid battery, the positive electrode current collecting layer and the negative electrode current collecting layer may have the form of a sintered body. When the positive electrode current collecting layer and / or the negative electrode current collecting layer have the form of a sintered body, they may be composed of a sintered body containing a conductive material and / or a sintering aid. The conductive material that may be contained in the positive electrode current collecting layer and / or the negative electrode current collecting layer may be selected from, for example, the same materials as the conductive material that may be contained in the positive electrode layer and / or the negative electrode layer. The sintering aid that may be contained in the positive electrode current collecting layer and / or the negative electrode current collecting layer may be selected from, for example, the same materials as the sintering aid that may be contained in the positive electrode layer and / or the negative electrode layer.

[0040] The thickness of the positive electrode current collecting layer and the negative electrode current collecting layer is not particularly limited. For example, the thickness of each of the positive electrode current collecting layer and the negative electrode current collecting layer may be 1 μm or more and 10 μm or less, and particularly 1 μm or more and 5 μm or less.

[0041] In the solid-state battery of the present disclosure, the positive electrode current collecting layer and / or the negative electrode current collecting layer are not essential, and a solid-state battery that does not have such a positive electrode current collecting layer and / or a negative electrode current collecting layer is also conceivable. In other words, the solid-state battery of the present invention may be a "current collecting-less" solid-state battery (see FIG. 2).

[0042] (External terminal) The solid-state battery stack (5) is provided with a terminal for connection to the outside (hereinafter, referred to as an "external terminal" or "external terminal 6"). In particular, it is preferable that a terminal for connection to the outside is provided as an "end electrode" on the side surface (specifically, the left and right side surfaces) of the solid-state battery stack (5). More specifically, as the external terminal 6, for example, as shown in FIG. 2, a positive electrode side terminal (positive electrode terminal) (6A) electrically connected to the positive electrode layer (1) and a negative electrode side terminal (negative electrode terminal) (6B) electrically connected to the negative electrode layer (2) may be provided on the solid-state battery stack 5. Such a terminal is preferably made of a material having a high electrical conductivity (or a conductive material). The material of the terminal is not particularly limited, but may be at least one selected from the group consisting of gold, silver, platinum, aluminum, tin, nickel, copper, manganese, cobalt, iron, titanium, and chromium. There is no particular limitation on the positions where the terminals are arranged, and they are not limited to the left and right side surfaces of the solid-state battery stack.

[0043] [Features of the Solid-State Battery Disclosed Herein] The present invention relates to a solid-state battery. For example, Fig. 1 shows a solid-state battery according to one embodiment of the present invention (hereinafter, may be referred to as "solid-state battery of the present disclosure"). As shown in Fig. 1, the solid-state battery of the present disclosure has at least one battery structural unit along the stacking direction, the battery structural unit including at least two electrode layers (1, 2) having different polarities and a solid electrolyte layer 3 interposed at least between the electrode layers (1, 2) (see Fig. 2).

[0044] The solid-state battery of the present disclosure includes an external terminal 6 (positive or negative terminal). For example, a positive terminal 6A and a negative terminal 6B are provided on opposing side surfaces (specifically, left and right side surfaces) of a solid-state battery stack 5 as shown in FIG.

[0045] As shown in FIG. 1, for example, the solid-state battery of the present disclosure may have a configuration in which active material sections (1', 2') that can be included in the electrode layer (1, 2) and an insulating section 4 (or a part thereof) are stacked on top of each other in a boundary region X with an external terminal 6, and the insulating section 4 covers the active material sections (1', 2') in a "sleeve-like" manner in cross-sectional view.

[0046] 1, for convenience of explanation, electrode layer 1 is shown as a positive electrode layer and electrode layer 2 is shown as a negative electrode layer, but electrode layer 1 may be a negative electrode layer, and therefore electrode layer 2 may be a positive electrode layer. In other words, external terminal 6 is shown as a positive electrode terminal for convenience of explanation, but external terminal 6 may be either a positive electrode terminal or a negative electrode terminal.

[0047] Below, each term will be explained, and then the features of the present invention will be described in more detail.

[0048] (Active material part) In the present disclosure, the term "active material portion" refers to a portion of the electrode layer that contains an electrode active material. More specifically, the term refers to a portion of the positive electrode layer that contains at least the above-mentioned "positive electrode active material" and a portion of the negative electrode layer that contains at least the above-mentioned "negative electrode active material."

[0049] (boundary area) In the present disclosure, a "boundary region" refers to a region in which an "electrode layer" and an "external terminal" can be arranged opposite each other, and in this boundary region, the "electrode layer" and the "external terminal" may or may not be electrically connected to each other.

[0050] In the solid-state battery of the present disclosure, an "insulating portion" can be disposed in such a boundary region. Therefore, in the solid-state battery of the present disclosure, the region in which such an "insulating portion" can be disposed can also be called a "boundary region."

[0051] More specifically, as shown in FIG. 1, a boundary region X exists in a region where an electrode layer 1 (e.g., a positive electrode layer) and an external terminal 6 (e.g., a positive electrode terminal) can be arranged opposite to each other, or in a region where an electrode layer 2 (e.g., a negative electrode layer) and an external terminal 6 (e.g., a positive electrode terminal) can be arranged opposite to each other.

[0052] For example, in the embodiment shown in FIG. 1, the electrode layer 1 and the external terminal 6 are electrically connected, and the electrode layer 2 and the external terminal 6 are not electrically connected via the insulating portion 4 .

[0053] (insulation part) In the present disclosure, an "insulating portion" (also referred to as an "electrode separator" or a "blank portion" or a "blank layer") means a region where at least an electrode layer (positive electrode layer and / or negative electrode layer) can face an external terminal, i.e., a portion where an electrode layer can be disposed in a boundary region with an external terminal and where the electrode layer and the external terminal can be separated and / or electrically insulated from each other. Specifically, it means a portion that separates and / or electrically insulates the electrode layer and the external terminal in the direction in which the positive electrode terminal and the negative electrode terminal of a solid-state battery face each other or in the left-right direction.

[0054] There are no particular limitations on the material that can form the insulating portion, but it is preferable that the insulating portion is formed from, for example, the above-mentioned "solid electrolyte" or "insulating material".

[0055] Examples of the "insulating material" include glass materials and ceramic materials. The "glass material" is not particularly limited, but may be at least one selected from the group consisting of soda-lime glass, potash glass, borate glass, borosilicate glass, barium borosilicate glass, zinc borate glass, barium borate glass, bismuth borosilicate glass, bismuth zinc borate glass, bismuth silicate glass, phosphate glass, aluminophosphate glass, and zinc phosphate glass. The "ceramic material" is not particularly limited, but may be at least one selected from the group consisting of aluminum oxide (Al2O3), boron nitride (BN), silicon dioxide (SiO2), silicon nitride (Si3N4), zirconium oxide (ZrO2), aluminum nitride (AlN), silicon carbide (SiC), and barium titanate (BaTiO3).

[0056] When the material that can constitute the insulating part contains a solid electrolyte, the solid electrolyte material that can be contained in this insulating part is preferably the same material as the solid electrolyte that can be contained in the above-mentioned “solid electrolyte layer.” By adopting such a configuration, the bonding strength between the insulating part and the solid electrolyte layer can be further improved.

[0057] (The "sleeve-shaped" part) The solid-state battery of the present disclosure is mainly characterized in that at least one of two electrode layers (specifically, a positive electrode layer 1 and a negative electrode layer 2) has a configuration in which active material parts (1', 2') included in the electrode layers (1, 2) and an insulating part 4 (or a part thereof) are stacked in the up-down direction in a boundary region X with an external terminal 6 (specifically, a positive electrode terminal), as shown in Fig. 1, for example, and the insulating part 4 covers the active material parts (1', 2') in a "sleeve-like" (arm-like) manner in a cross-sectional view. In other words, the electrode layer covered by the sleeve-shaped part of the insulating part in a cross-sectional view is the active material part.

[0058] For example, in the embodiment shown in FIG. 1, the "sleeve-shaped" portion of insulating portion 4 is indicated by the symbol "S" (Sleeve), and the other "non-sleeve-shaped" portion is indicated by the symbol "NS" (Non-Sleeve).

[0059] In the boundary region X shown in Fig. 1, it is preferable that the sleeve-shaped portion (S) of the insulating part 4 is provided so as to sandwich the active material parts (1', 2') from above and below in the stacking direction in a cross-sectional view. In other words, it is preferable that the sleeve-shaped portion (S) of the insulating part 4 is arranged so as to sandwich the active material parts (1', 2') of the electrode layers (1, 2) from above and below. To explain more clearly, it is preferable that the shape of the sleeve-shaped portion (S) of the insulating part 4 in a cross-sectional view is, for example, like a robot arm, a crab's claws, or a beak.

[0060] In the embodiment shown in FIG. 1, the sleeve-shaped portion (S) is shown to have a rectangular or oblong shape in cross-section, but the boundary between the sleeve-shaped portion (S) and the active material portion (1', 2') may be a gentle curve, may be curved inward or outward, may have a fillet shape, or may have a shape that tapers toward the external terminal 6.

[0061] By forming the “sleeve-shaped” portion (S) in this manner, it is possible to suppress the extension (exudation, protrusion) of the active material portions (1', 2') of the electrode layers (1, 2) in the vertical direction (or stacking direction), particularly during the production of the solid-state battery stack, and to suppress the proximity of the active material portions to electrode layers of opposite polarity, and after production, it is possible to further prevent short circuits between electrode layers facing each other in the stacking direction.

[0062] Furthermore, by forming the “sleeve-shaped” portion (S) in this manner, it is possible to further suppress extension (exudation, protrusion) of the active material portion 2′ of the electrode layer 2 in the left-right direction (or the direction in which the positive electrode terminal and the negative electrode terminal face each other), particularly in the manufacture of the solid-state battery laminate, and it is possible to further suppress the electrode layer 2 from being close to the external terminal 6 after manufacture, thereby making it possible to further prevent a short circuit between the electrode layer 2 and the facing external terminal 6.

[0063] By forming the “sleeve-shaped” portion (S) in this manner, the contact area of ​​the insulating portion 4 with the solid electrolyte layer 3 can be secured more effectively, and peeling at the interface of the electrode layers (1, 2), specifically peeling from the solid electrolyte layer, and particularly interlayer peeling, can be more effectively suppressed during production of the solid-state battery or during charging and discharging of the solid-state battery.

[0064] Here, as shown in FIG. 1, in a cross-sectional view, the ratio (length / thickness ratio) of the length (specifically, the dimension in the left-right direction) of the sleeve-shaped portion (S) of the insulating part 4 to the thickness (specifically, the dimension in the stacking direction (vertical direction)) of the electrode layers (1, 2) is, for example, not less than 0.05% and not more than 10%.

[0065] As shown in FIG. 1, it is preferable that a portion (S) where the active material portion 1' of the electrode layer 1 (specifically, the positive electrode layer 1) is covered in a sleeve-like shape with an insulating portion 4 and a portion (S) where the active material portion 2' of the electrode layer 2 (specifically, the negative electrode layer 2) is covered in a sleeve-like shape with an insulating portion 4 overlap in the stacking direction (vertical direction) (for example, the portion indicated by distance D1 in FIG. 1). By forming such an overlapping portion, it is possible to further prevent short circuits and delamination between electrode layers facing each other in the stacking direction.

[0066] The length of the overlapping portion of the sleeve-shaped portion (S) of the insulating portion 4 is, as the length in the direction in which the positive electrode terminal and the negative electrode terminal face each other (left-right direction) indicated by the distance D1 in the cross-sectional view of Figure 1, for example, 10 μm or more and 200 μm or less, preferably 30 μm or more and 50 μm or less.

[0067] The thickness (T s ) is, for example, 1% or more and 50% or less of the thickness (T3) of the solid electrolyte layer 3. s / T3×100(%)). Since the cross-sectional shape of the sleeve-shaped portion (S) may be rectangular or a shape other than a rectangular shape, the thickness (T s) may be the "average thickness" obtained by dividing the area of ​​the sleeve-shaped portion (S) (specifically, the area of ​​its cross-section) by the length of the sleeve-shaped portion (S) (specifically, its left-right dimension). The thickness (T s ) can be determined, for example, by measuring from photographs taken with a scanning electron microscope (SEM). In the illustrated embodiment, the thickness (T s ) may be different or the same.

[0068] In the "non-sleeve-shaped" portion (NS) of the insulating portion 4, for example, as shown in the electrode layer 1 (specifically, the positive electrode layer 1), the active material portion 1' may extend to an external terminal 6 (specifically, a positive electrode terminal), and the electrode layer 1 may be electrically connected to the external terminal 6. In other words, an electrical "connected state" may be formed.

[0069] Furthermore, in the "non-sleeve-shaped" portion (NS) of the insulating part 4, for example, as shown in the electrode layer 2 (specifically, the negative electrode layer 2), the active material part 2' does not extend to the external terminal 6 (specifically, the positive electrode terminal), and the electrode layer 2 does not have to be electrically connected to the external terminal 6. In other words, the insulating part 4 may form an electrical "disconnected state."

[0070] In this way, by having the insulating portion 4 have the "non-sleeve-shaped" portion (NS), it is possible to arbitrarily select the electrical connection with the external terminal of the electrode layer.

[0071] The present invention will be described in detail below with reference to preferred embodiments.

[0072] (First embodiment) As a solid-state battery according to a preferred embodiment of the present invention, for example, a solid-state battery 10 according to a first embodiment is shown in FIG.

[0073] The solid-state battery 10 shown in FIG. 2 has a solid-state battery stack 5 that includes at least one battery constituent unit along the stacking direction, the battery constituent unit including a positive electrode layer 1, a negative electrode layer 2, and a solid electrolyte layer 3 interposed at least between the positive electrode layer 1 and the negative electrode layer 2. The solid-state battery 10 includes external terminals, a positive electrode terminal 6A and a negative electrode terminal 6B, provided on opposing side surfaces (specifically, left and right side surfaces) of the solid-state battery stack 5, respectively. In the solid-state battery 10, at least one of the positive electrode layer 1 and the negative electrode layer 2 is disposed at a boundary region (X a ,X b ), the active material parts (1', 2') of the electrode layers (1, 2) and the insulating part (or a part thereof) are stacked in the up-down direction, and the insulating part covers the active material parts (1', 2') in a sleeve-like shape in cross-sectional view.

[0074] In the positive electrode layer 1, a boundary region X a In the positive electrode layer 1, an insulating portion 4a on the positive electrode side is present. The positive electrode layer 1 (or the active material portion 1') is electrically connected to the positive electrode terminal 6A. More specifically, the positive electrode layer 1 extends through the interior (inner side) of the insulating portion 4a and is electrically connected to the positive electrode terminal 6A (forming a connected state). In the positive electrode layer 1, a boundary region X b Even in this case, the insulating portion 4b on the negative electrode side is present, and the positive electrode layer 1 is not electrically connected to the negative electrode terminal 6B (forming a non-connected state). The insulating part 4a on the positive electrode side and the insulating part 4b on the negative electrode side that can be disposed on the positive electrode layer 1 can be the same as the insulating part 4 (upper part and lower part) shown in FIG.

[0075] In the negative electrode layer 2, a boundary region X b In the negative electrode layer 2, the negative electrode layer 2 is electrically connected to the negative electrode terminal 6B. In the negative electrode layer 2, a boundary region X a , an insulating portion 4 is present on the positive electrode side, and an active material portion 2' of a negative electrode layer 2 is not electrically connected to a positive electrode terminal 6A (formation of a non-connected state). The insulating part 4 on the positive electrode side that can be disposed on the negative electrode layer 2 can be the same as the insulating part 4 (lower part) shown in FIG. The boundary region X between the negative electrode layer 2 and the negative electrode terminal 6B b In the negative electrode layer 6B, a negative electrode insulating part may be provided similarly to the positive electrode insulating part 4a. In this case, the negative electrode layer 2 may extend through the interior (inside) of the negative electrode insulating part (not shown) and be electrically connected to the negative electrode terminal 6B (forming a connected state).

[0076] As shown in FIG. 2, in the solid-state battery 10, it is preferable that the sleeve-shaped portion of the insulating portion and the electrode layer (or the portion of the active material portion not covered by the insulating portion) are flush with each other in a cross-sectional view.

[0077] More specifically, as shown in an enlarged view in FIG. 3, in the positive electrode layer 1, it is preferable that the sleeve-shaped portion (S) of the insulating portion 4a and the positive electrode layer 1 (specifically, the portion (F) of the positive electrode layer 1 where the active material portion 1′ is not covered with the insulating portion 4a) are flush with each other. Similarly, in the negative electrode layer 2, it is preferable that the sleeve-shaped portion (S) of the insulating portion 4 and the negative electrode layer 2 (specifically, the portion (F) of the negative electrode layer 2 where the active material portion 2' is not covered with the insulating portion 4) are flush with each other.

[0078] 3, the thickness of each layer can be made uniform, which further improves the structural stability of the solid-state battery. Also, the uniform thickness of each layer can further suppress delamination at the interface between the electrode layer and the solid electrolyte layer.

[0079] In the embodiment shown in FIG. 3, in a cross-sectional view, the ratio (length / thickness ratio) of the length (specifically, the dimension in the left-right direction) of the sleeve-shaped portion (S) of the insulating part 4 to the thickness (specifically, the dimension in the stacking direction (vertical direction)) of the electrode layers (1, 2) is, for example, 0.05% or more and 10% or less.

[0080] It is also preferable that the sleeve-shaped portion (S) of the insulating portion 4a of the positive electrode layer 1 and the sleeve-shaped portion (S) of the insulating portion 4 of the negative electrode layer 2 overlap in the stacking direction (vertical direction). The distance D1 of the overlapping portion is, as the length in the direction in which the positive electrode terminal and the negative electrode terminal of the solid-state battery 10 face each other (horizontal direction), for example, 10 μm to 200 μm, preferably 30 μm to 50 μm.

[0081] In the solid-state battery 10, there is no particular limit to the total length of the sleeve-shaped portion (S) and the non-sleeve-shaped portion (NS), and for example, the positive electrode layer 1 may be longer or the negative electrode layer 2 may be longer as shown in Fig. 3. For example, the insulating portions of the positive electrode layer 1 and the negative electrode layer 2 may be the same length as shown in Fig. 1.

[0082] With this configuration, it is possible to further suppress electrical short circuits between the electrode layers (1, 2) (i.e., short circuits in the vertical direction), electrical short circuits between the negative electrode layer 2 and the positive electrode terminal 6A and between the positive electrode layer 1 and the negative electrode terminal 6B (i.e., short circuits in the horizontal direction), and delamination between the electrode layer (1, 2) and the solid electrolyte layer 3.

[0083] Second embodiment As a solid-state battery according to a preferred embodiment of the present invention, a solid-state battery 20 according to a second embodiment is shown in FIGS.

[0084] The configuration of the solid-state battery 20 of the second embodiment is similar to the configuration of the solid-state battery 10 of the first embodiment, but the solid-state battery 20 of the second embodiment differs from the solid-state battery 10 in that the positive electrode layer 21 includes a positive electrode current collecting layer 21c.

[0085] In the positive electrode layer 21, the positive electrode current collecting layer 21c extends so as to pass between the sleeve-shaped insulating portion 24a in a cross-sectional view, and is electrically connected to the positive electrode terminal 26A, in particular, through the non-sleeve-shaped portion (NS) of the insulating portion 24a (Figure 5).

[0086] In the solid-state battery 20, like the positive electrode layer 21, the negative electrode layer 22 may also be provided with a negative electrode current collecting layer (not shown).

[0087] In the embodiment shown in FIG. 5, in a cross-sectional view, the ratio (length / thickness ratio) of the length (specifically, the dimension in the left-right direction) of the sleeve-shaped portion (S) to the thickness (specifically, the dimension in the stacking direction (up-down direction)) of the electrode layers (21, 22) is, for example, 0.05% or more and 10% or less.

[0088] 5, for example, it is preferable that the sleeve-shaped portion (S) of the insulating portion 24a of the positive electrode layer 21 and the sleeve-shaped portion (S) of the insulating portion 24 of the negative electrode layer 22 overlap in the stacking direction (vertical direction). The distance D2 of the overlapping portion is, as the length in the direction in which the positive electrode terminal and the negative electrode terminal face each other (horizontal direction), for example, 10 μm to 200 μm, preferably 30 μm to 50 μm.

[0089] In the solid-state battery 20 of the second embodiment, the insulating portions 24a and 24b of the positive electrode layer 21 and the insulating portion 24 of the negative electrode layer 22 can have a configuration similar to that of the insulating portions (4a, 4b, 4) of the solid-state battery 10 of the first embodiment (FIGS. 2 and 4). Therefore, even if the electrode layers (21, 22) include a current collecting layer, that is, even if the electrode layers are multi-layered, electrical short circuits (i.e., short circuits in the vertical direction) between the electrode layers (21, 22), electrical short circuits between the negative electrode layer 22 and the positive electrode terminal 26A and electrical short circuits (i.e., short circuits in the horizontal direction) between the positive electrode layer 21 and the negative electrode terminal 26B, and delamination between the electrode layers (21, 22) and the solid electrolyte layer 23 can be similarly and more effectively suppressed.

[0090] Third embodiment As a solid-state battery according to a preferred embodiment of the present invention, a solid-state battery 30 according to a third embodiment is shown in FIGS.

[0091] The configuration of the solid-state battery 30 of the third embodiment is similar to the configuration of the solid-state battery 20 of the second embodiment, but the solid-state battery 30 of the third embodiment differs from the solid-state battery 20 in that the shapes of the insulating portions 34a and 34b of the positive electrode layer 31 and the insulating portion 34 of the negative electrode layer 32 are changed.

[0092] In the solid-state battery 30, in a cross-sectional view, the sleeve-shaped portion of the insulating portion is raised or protruding or higher than the portion of the electrode layer (or active material portion) that is not covered with the insulating portion.

[0093] 7, the sleeve-shaped portion (S) of the insulating portion 34a of the positive electrode layer 31 is raised or protruding or higher than the portion (F) of the positive electrode layer 31 (or the active material portion (31')) that is not covered with the insulating portion 34a. More specifically, the sleeve-shaped portion (S) is raised or protruding or higher in the up-down direction in the stacking direction. The sleeve-shaped portion (S) of the insulating portion 34 of the negative electrode layer 32 is protruding or bulging or higher than a portion (F) of the negative electrode layer 32 (or the active material portion (32')) that is not covered with the insulating portion 34. More specifically, the sleeve-shaped portion (S) is protruding or bulging or higher in the up-down direction in the stacking direction. In the illustrated embodiment, the sleeve-shaped portion (S) is shown to be raised in a rectangular or oblong shape when viewed in cross section, but it may also be raised or bulged or elevated in the form of a gentle curve or a curved arc.

[0094] The thickness of the sleeve-shaped part (S) (T 3S ) is the thickness (T 31 ,T 32 ), for example, the height is raised by 1% to 50% (T 3S / T 31 or T 32 ×100(%)). The thickness of the sleeve-shaped part (S) (T 3S ) is the thickness (T 33 ), for example, it is raised or protruding or elevated by a height in the range of 1% to 50% (T 3S / T 33 ×100(%)). In the illustrated embodiment, the thickness (T 3s) may be different or the same.

[0095] In the solid-state battery 30, in a cross-sectional view, it is preferable that the protruding sleeve-shaped portion of the insulating portion protrudes or swells or is higher than the portion of the insulating portion that contacts the external terminal.

[0096] More specifically, as shown in FIG. 7, in a cross-sectional view, it is preferable that the protruding sleeve-shaped portion (S) of the insulating portion 34a of the positive electrode layer 31 is protruding more than the portion of the insulating portion 34a that contacts the positive electrode terminal 36A (specifically, the end portion of the non-sleeve-shaped portion (NS) that contacts the positive electrode terminal 36A on the right side). In addition, in a cross-sectional view, it is preferable that the protruding sleeve-shaped portion (S) of the insulating portion 34 of the negative electrode layer 32 is protruding, raised, or higher than the portion of the insulating portion 34 that contacts the positive electrode terminal 36A (specifically, the end portion of the non-sleeve-shaped portion (NS) that contacts the positive electrode terminal 36A on the right side).

[0097] In the embodiment shown in FIG. 7, the thickness of the electrode layers (31, 32) in cross-sectional view (specifically, the dimension (T 31 ,T 32 The ratio of the length (specifically, the dimension in the left-right direction) of the sleeve-shaped portion (S) to the thickness (length / thickness) is, for example, 0.05% or more and 10% or less.

[0098] It is also preferable that the sleeve-shaped portion (S) of the insulating portion 34a of the positive electrode layer 31 and the sleeve-shaped portion (S) of the insulating portion 34 of the negative electrode layer 32 overlap in the stacking direction (vertical direction). The distance D3 of the overlapping portion is, as the length in the direction in which the positive electrode terminal and the negative electrode terminal face each other (horizontal direction), for example, 10 μm to 200 μm, preferably 30 μm to 50 μm.

[0099] In the solid-state battery 30 of the third embodiment, the sleeve-shaped portion (S) is raised, which can further suppress an electrical short circuit between the electrode layers (31, 32) (i.e., a short circuit in the vertical direction), an electrical short circuit between the negative electrode layer 32 and the positive electrode terminal 36A and an electrical short circuit between the positive electrode layer 31 and the negative electrode terminal 36B (i.e., a short circuit in the horizontal direction), and delamination between the electrode layers (31, 32) and the solid electrolyte layer 33.

[0100] Furthermore, in the solid-state battery 30 of the third embodiment, compared to the solid-state batteries of the first and second embodiments, the sleeve-shaped portion (S) is raised, which can increase the amount of active material filled in each electrode layer, thereby further improving the energy density.

[0101] In the solid-state battery 30 of the third embodiment, the lower side (lower surface) of the insulating portion may be flush with the portion (F) of the electrode layer that is not covered in a sleeve shape, as in the first and second embodiments (see FIGS. 1 to 5).

[0102] (Fourth embodiment) As a solid-state battery according to a preferred embodiment of the present invention, a solid-state battery 40 according to a fourth embodiment is shown in FIGS.

[0103] The configuration of the solid-state battery 40 of the fourth embodiment is similar to the configuration of the solid-state battery 30 of the third embodiment, but the solid-state battery 40 of the fourth embodiment differs from the solid-state battery 30 in that the shapes of the insulating parts 44a and 44b of the positive electrode layer 41 and the insulating part 44 of the negative electrode layer 42, in particular, the shape of the "non-sleeve-shaped portion" are changed.

[0104] In the solid-state battery 40, in a cross-sectional view, the sleeve-shaped portion of the insulating portion is raised or protruding or higher than the portion of the electrode layer (or active material portion) that is not covered by the insulating portion.

[0105] More specifically, as shown in an enlarged view in FIG. 9, the sleeve-shaped portion (S) of the insulating portion 44a of the positive electrode layer 41 is protruding, raised, or higher than the portion (F) of the positive electrode layer 41 (or the active material portion (41')) that is not covered by the insulating portion 44a. The sleeve-shaped portion (S) of the insulating portion 44 of the negative electrode layer 42 protrudes higher than the portion (F) of the negative electrode layer 42 (or the active material portion (42')) that is not covered by the insulating portion 44. In the illustrated embodiment, the sleeve-shaped portion (S) is shown to be raised in a rectangular or oblong shape when viewed in cross section, but it may also be raised in the form of a gentle curve or a curved arc.

[0106] The thickness of the sleeve-shaped part (S) (T 4S ) is the thickness (T 41 ,T 42 ), for example, it is raised or protruding or elevated by a height in the range of 1% to 50% (T 4S / T 41 or T 42 ×100(%)). The thickness of the sleeve-shaped part (S) (T 4S ) is the thickness (T 43 ), for example, it is raised or protruding or elevated by a height in the range of 1% to 50% (T 4S / T 43 ×100(%)). In the illustrated embodiment, the thickness (T 4s ) may be different or the same.

[0107] In the solid-state battery 40, in a cross-sectional view, it is preferable that the raised sleeve-shaped portion of the insulating portion is flush with the portion where the insulating portion contacts the external terminal.

[0108] More specifically, as shown in an enlarged view in FIG. 9, in a cross-sectional view, it is preferable that the protruding sleeve-shaped portion (S) of the insulating portion 44a of the positive electrode layer 41 is flush with or has the same height as the portion of the insulating portion 44a that contacts the positive electrode terminal 46A (specifically, the end portion of the non-sleeve-shaped portion (NS) that contacts the positive electrode terminal 46A on the right side). In addition, in a cross-sectional view, it is preferable that the protruding sleeve-shaped portion (S) of the insulating portion 44 of the negative electrode layer 42 is flush with or has the same height as the portion of the insulating portion 44 that contacts the positive electrode terminal 46A (specifically, the end portion of the non-sleeve-shaped portion (NS) that contacts the positive electrode terminal 46A on the right side).

[0109] In the embodiment shown in FIG. 9, the thickness of the electrode layers (41, 42) in cross-sectional view (specifically, the dimension (T 41 ,T 42 The ratio of the length (specifically, the dimension in the left-right direction) of the sleeve-shaped portion (S) to the thickness (length / thickness) is, for example, 0.05% or more and 10% or less.

[0110] It is also preferable that the sleeve-shaped portion (S) of the insulating portion 44a of the positive electrode layer 41 and the sleeve-shaped portion (S) of the insulating portion 44 of the negative electrode layer 42 overlap in the stacking direction (i.e., the up-down direction). The distance D4 of the overlapping portion is, as the length in the direction in which the positive electrode terminal and the negative electrode terminal face each other or in the left-right direction, for example, 10 μm to 200 μm, or 30 μm to 50 μm.

[0111] In the solid-state battery 40 of the fourth embodiment, the sleeve-shaped portion (S) is raised or protruding or elevated, which can further suppress an electrical short circuit between the electrode layers (41, 42) (i.e., a short circuit in the up-down direction), an electrical short circuit between the negative electrode layer 42 and the positive electrode terminal 46A and an electrical short circuit between the positive electrode layer 41 and the negative electrode terminal 46B (i.e., a short circuit in the left-right direction), and delamination between the electrode layers (41, 42) and the solid electrolyte layer 43.

[0112] In the solid-state battery 40 of the fourth embodiment, the thickness of the non-sleeve-shaped portion (NS) of the insulating part is increased compared to the solid-state batteries of the first to third embodiments, and therefore, electrical short-circuiting between the negative electrode layer 42 and the positive electrode terminal 46A and between the positive electrode layer 41 and the negative electrode terminal 46B (i.e., short-circuiting in the left-right direction) can be further suppressed.

[0113] In the solid-state battery 40 of the fourth embodiment, the lower side (lower surface) of the insulating part may be flush with the portion (F) of each electrode layer that is not covered by the sleeve-shaped portion, as in the first and second embodiments (see FIGS. 1 to 5).

[0114] The solid-state battery of the present disclosure may be a combination of the configurations of the above first to fourth embodiments as necessary, and in particular, the insulating parts used in the first to fourth embodiments may be used in appropriate combination.

[0115] The solid-state battery of the present disclosure is not limited to the above embodiment.

[0116] (Solid-state battery manufacturing method) The method for producing the solid-state battery of the present disclosure will be briefly described below.

[0117] (Solid-state battery stack formation) 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 combination of these methods. In other words, the solid-state battery laminate itself may be manufactured in accordance with a conventional manufacturing method for solid-state batteries (therefore, raw materials such as the solid electrolyte, organic binder, solvent, optional additives, positive electrode active material, and negative electrode active material described below may be those used in the manufacture of known solid-state batteries).

[0118] In the following, in order to better understand the present invention, one manufacturing method will be described as an example, but the present invention is not limited to this method. In addition, the chronological matters such as the order of description below are merely for the convenience of explanation, and are not necessarily bound by them. Incidentally, the formation of the insulating portion, which is a characteristic feature of the present invention, will be specifically described separately below.

[0119] (Laminated block formation) A slurry is prepared by mixing a solid electrolyte, an organic binder, a solvent, and any additives. The slurry is then molded into a sheet having a thickness of about 10 μm after firing. A paste for a positive electrode is prepared by mixing a positive electrode active material, a solid electrolyte, a conductive material, an organic binder, a solvent, any additives, etc. Similarly, a paste for a negative electrode is prepared by mixing a negative electrode active material, a solid electrolyte, a conductive material, an organic binder, a solvent, any additives, etc. Print the paste for the positive electrode on the sheet, and if necessary, print the current collecting layer. Similarly, print the paste for the negative electrode on the sheet, and if necessary, print the current collecting layer. A laminate is obtained by alternately stacking sheets printed with a paste for a positive electrode and sheets printed with a paste for a negative electrode. The outermost layer (the uppermost layer and / or the lowermost layer) of the laminate may be an electrolyte layer, an insulating layer (a layer that does not conduct electricity, for example, a layer that may be composed of a non-conductive material such as a glass material and / or a ceramic material), or an electrode layer.

[0120] (Battery sintered body formation) After the laminate is pressure-bonded and integrated, it is cut to a predetermined size. The cut laminate is degreased and fired. This results in a sintered laminate. Note that the laminate may be degreased and fired before cutting, and then cut.

[0121] (External terminal formation) The external terminal (or end electrode) on the positive electrode side can be formed by applying a conductive paste to the exposed side surface of the positive electrode in the sintered laminate. Similarly, the external terminal (or end electrode) on the negative electrode side can be formed by applying a conductive paste to the exposed side surface of the negative electrode in the sintered laminate.

[0122] The external terminals on the positive and negative electrodes do not necessarily have to be formed after sintering the laminate, but may be formed before firing and then sintered simultaneously.

[0123] (Formation of insulating part) In the above-mentioned "formation of laminated block" (before firing), the insulating portion can be formed, if necessary, as follows, for example.

[0124] A solid electrolyte and / or an insulating material, a binder, an organic binder, a solvent, and any additives are mixed to prepare an insulating paste (also called an electrode separation paste or a blanking paste).

[0125] For example, the insulating portion 24a having the shape shown in FIG. 5 (upper part) can be formed according to the procedure shown in FIG. (A) An insulating paste P2 is printed on a sheet P1 formed from a slurry containing a solid electrolyte. At this time, it is preferable to print the insulating paste P2 so as to form a desired "sleeve-shaped" portion. (B) An electrode paste (positive electrode paste or negative electrode paste) P3 is printed on a portion of the sheet P1 and the paste P2 (the portion that will become the "sleeve-shaped" portion). (C) A current collecting layer (paste) P4 is printed on the entire surface of the paste P2 and the paste P3 as required. (D) Electrode paste P5 is printed on top of current collecting layer P4 (electrode paste P5 has the same polarity as electrode paste P3). At this time, it is preferable to print electrode paste P5 so that a desired "sleeve-shaped" portion can be formed. (E) The current collecting layer P4 and the part of the paste P5 (that will be covered by the "sleeve-like" part) are printed with an insulating paste P6, which is preferably the same as paste P2.

[0126] In this manner, for example, an insulating portion having a shape as shown in FIG. 5 (upper part) can be finally formed by firing, but the formation of the insulating portion is not limited to the above method.

[0127] For example, the insulating portion 24 having the shape shown in FIG. 5 (lower part) can be formed according to the procedure shown in FIG. (A) An insulating paste Q2 is printed on a sheet Q1 formed from a slurry containing a solid electrolyte. At this time, it is preferable to print the insulating paste so that a desired "sleeve-shaped" portion can be formed. (B) An electrode paste (positive electrode paste or negative electrode paste) Q3 is printed on a portion of the sheet Q1 and the paste Q2 (the portion that will become the "sleeve-shaped" portion). (C) Print paste Q2 and parts of paste Q3 (where they will be covered by the "sleeve-like" parts) with insulating paste Q4, preferably the same as paste Q2.

[0128] In this way, for example, an insulating part having a shape as shown in Fig. 5 (lower part) can be finally formed by firing. However, the formation of the insulating part is not limited to the above method.

[0129] By forming the insulating portion according to the above-described procedure, it is possible to form insulating portions of various variations.

[0130] Although a desired solid-state battery can be finally obtained through the above-mentioned steps, the method for producing the solid-state battery is not limited to the above-mentioned method. [Industrial Applicability]

[0131] The solid-state battery of the present invention can be utilized in various fields where battery use or power storage can be envisaged. Although merely illustrative, the solid-state battery of the present invention can be used in the electrical, information and communication fields where electrical and electronic devices can be used (for example, electrical and electronic devices fields 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, and smart watches, or mobile device fields), household and small industrial applications (for example, power tools, golf carts, household, nursing care and industrial robots), large industrial applications (for example, forklifts, elevators, and port cranes), transportation systems (for example, hybrid automobiles, electric automobiles, buses, trains, electrically assisted bicycles, and electric motorcycles), power system applications (for example, various power generation, road conditioners, smart grids, and general household installation type power storage systems), medical applications (medical devices such as earphone hearing aids), pharmaceutical applications (medical management systems), IoT, and space and deep sea applications (for example, space probes, submersible research vessels, and the like). [Explanation of symbols]

[0132] 1,21,31,41,110,210 Electrode layer (positive electrode layer) 1',21',31',41' Active material part (positive electrode active material part) 2,22,32,42,120,220 Electrode layer (negative electrode layer) 2',22',32',42' Active material part (negative electrode active material part) 3,23,33,43,130,230 solid electrolyte layer 4,24,34,44,140,240 Insulation 4a, 24a, 34a, 44a, 240a Insulation part (positive side) 4b, 24b, 34b, 44b, 240b Insulation part (negative side) 5,25,35,45,150,250 Solid-state battery stack 6 External terminals 6A,26A,36A,46A,160A,260A Positive terminal 6B,26B,36B,46B,160B,260B Negative terminal 10,20,30,40,100,200 Solid state battery 21a, 31a, 41a Cathode active material part (upper side) 21b, 31b, 41b Cathode active material part (lower side) 21c,31c,41c,211 Positive electrode current collecting layer X bounding area X a Boundary area (positive side) X b Boundary area (negative side) S Sleeve-shaped part NS Non-sleeve part F: Part of the electrode layer that is not covered with insulation

Claims

1. a solid-state battery stack including at least one battery building unit including a positive electrode layer, a negative electrode layer, and a solid electrolyte layer interposed between the positive electrode layer and the negative electrode layer; a positive electrode terminal and a negative electrode terminal are provided on opposite sides of the solid-state battery stack, at least one of the positive electrode layer and the negative electrode layer has a configuration in which an active material portion and an insulating portion of the electrode layer are laminated together in a boundary region with the external terminal, The insulating portion covers the active material portion in a sleeve-like manner in cross-sectional view, A solid-state battery, wherein a portion of the external terminal is in contact with the insulating portion.

2. The solid-state battery according to claim 1 , wherein the insulating portions are provided so as to sandwich the active material portion from above and below in the stacking direction in a cross-sectional view in the boundary region.

3. The solid-state battery according to claim 1 or 2, wherein the positive electrode layer is electrically connected to the positive electrode terminal at the boundary region.

4. 4. The solid-state battery according to claim 1, wherein a ratio of a length of the sleeve-shaped portion of the insulating part to a thickness of the electrode layer in a cross-sectional view is 0.05% or more and 10% or less.

5. 5. The solid-state battery according to claim 1, wherein the sleeve-shaped portion of the insulating part and the electrode layer are flush with each other in a cross-sectional view.

6. 5. The solid-state battery according to claim 1, wherein, in a cross-sectional view, the sleeve-shaped portion of the insulating portion is raised higher than a portion of the electrode layer that is not covered by the insulating portion.

7. The solid-state battery according to claim 6 , wherein, in a cross-sectional view, the raised sleeve-shaped portion of the insulating portion is raised higher than a portion of the insulating portion that contacts the external terminal.

8. The solid-state battery according to claim 6 , wherein in a cross-sectional view, the raised sleeve-shaped portion of the insulating portion is flush with a portion of the insulating portion that contacts the external terminal.

9. The solid-state battery according to any one of claims 1 to 8, wherein the positive electrode layer has a current collecting layer, and the current collecting layer extends so as to pass between the sleeve-shaped insulating portion in a cross-sectional view.

10. The solid-state battery according to any one of claims 1 to 9, wherein the positive electrode layer and the negative electrode layer are layers capable of absorbing and releasing lithium ions.

Images