Battery

Abstract

A battery comprises: a solid state battery unit having a first electrode layer, a second electrode layer, and at least one power generating element including a first solid electrolyte layer that is positioned between the first electrode layer and the second electrode layer; and a structure that has a second solid electrolyte layer having a first main surface in contact with the at least one power generating element on a side surface of the solid state battery unit and a second main surface on the opposite side of the second solid electrolyte layer to the first main surface, and a reference electrode in contact with the second main surface.

Description

[Technical Field]

[0001] The present disclosure relates to batteries. [Background technology]

[0002] Solid-state batteries, which use flame-retardant solid electrolytes instead of the flammable organic solvent-containing electrolytes used in conventional batteries such as non-aqueous electrolyte lithium-ion secondary batteries, offer significant advantages in terms of basic safety performance. Therefore, solid-state batteries are seen as promising next-generation batteries due to their potential in terms of cost and energy density, such as the simplification of safety devices, and the race to develop them is accelerating.

[0003] Furthermore, if it is possible to measure the electrical characteristics, such as the potential of each electrode, such as the positive electrode and negative electrode, during actual use of the battery, it will be possible to more accurately understand the electrode state and perform more appropriate battery control based on the measured values, which will make it possible to maintain high performance characteristics and improve performance, such as safety, cycle characteristics, and storage characteristics.

[0004] A three-electrode measurement method using a reference electrode is known as a method for investigating the potential and electrochemical behavior of each electrode. For example, Non-Patent Document 1 describes the configuration of various solid-state batteries capable of three-electrode measurement. Patent Document 1 also discloses a solid-state battery in which a positive electrode current collector, a positive electrode, a solid electrolyte layer, a negative electrode, and a negative electrode current collector are stacked, and which includes a third electrode as a reference electrode in contact with a solid electrolyte layer or a solid electrolyte portion that is provided so as to connect the positive electrode, the solid electrolyte layer, and the negative electrode with a width that matches the length of the side surfaces of the positive electrode, the solid electrolyte layer, and the negative electrode. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-20915 [Non-patent literature]

[0006] [Non-Patent Document 1] Electrochemical Society, "Understanding Electrochemical Measurement Methods through Q&A," Mimizukusha, December 2009, p.10 Summary of the Invention [Problem to be solved by the invention]

[0007] To achieve high performance and high energy density in all-solid-state batteries, it is common to thin and laminate the positive and negative electrodes and solid electrolyte layers. To construct such an all-solid-state battery capable of three-electrode measurement, unlike liquid-based batteries where electrochemical contact is established simply by immersing the battery in an electrolyte solution, a solid electrolyte layer must be electrochemically bonded and contacted between the battery and the reference electrode. Conventional three-electrode measurement batteries require precise formation of the solid electrolyte layer for the reference electrode and precise placement of the reference electrode, making it difficult to measure electrical characteristics using three-electrode measurement. Furthermore, conventional structures can be prone to damage and short circuits in the reference electrode, so improved reliability is also required for batteries capable of three-electrode measurement.

[0008] Therefore, the present disclosure provides a highly reliable battery that allows the electrical characteristics of the electrodes to be measured. [Means for solving the problem]

[0009] A battery according to one embodiment of the present disclosure includes: a solid-state battery unit having at least one power generation element unit including a first electrode layer, a second electrode layer, and a first solid electrolyte layer located between the first electrode layer and the second electrode layer; a second solid electrolyte layer having a first main surface in contact with the at least one power generation element unit on a side surface of the solid-state battery unit and a second main surface opposite to the first main surface; and a structure having a reference electrode in contact with the second main surface. [Effects of the Invention]

[0010] According to the present disclosure, the electrical characteristics of electrodes can be measured, and a highly reliable battery can be provided. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a cross-sectional view showing a schematic configuration of a battery according to an embodiment. [Figure 2A] FIG. 2A is a side view showing a schematic configuration of a battery according to an embodiment. [Figure 2B] FIG. 2B is a side view showing the battery shown in FIG. 2A with the reference electrode current collector removed. [Figure 3A] FIG. 3A is a diagram for explaining a method for measuring electrical characteristics of a battery according to an embodiment. [Figure 3B] FIG. 3B is a diagram for explaining a method for measuring the electrical characteristics of the battery according to the embodiment. [Figure 4] FIG. 4 is a cross-sectional view showing a schematic configuration of a battery according to a first modification of the embodiment. [Figure 5] FIG. 5 is a cross-sectional view showing a schematic configuration of a battery according to the second modification of the embodiment. [Figure 6] FIG. 6 is a cross-sectional view showing a schematic configuration of a battery according to a third modification of the embodiment. [Figure 7] FIG. 7 is a cross-sectional view showing a schematic configuration of a battery according to a fourth modification of the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] (Summary of the Disclosure) An outline of one aspect of the present disclosure is as follows.

[0013] A battery according to one embodiment of the present disclosure includes a solid-state battery unit having at least one power generating element unit including a first electrode layer, a second electrode layer, and a first solid electrolyte layer located between the first electrode layer and the second electrode layer, and a structure including a second solid electrolyte layer having a first main surface in contact with the at least one power generating element unit on a side surface of the solid-state battery unit and a second main surface opposite to the first main surface, and a reference electrode in contact with the second main surface. This allows the electrical characteristics of the electrodes to be measured, providing a highly reliable battery. Furthermore, for example, in a plan view with respect to the second principal surface, the area of ​​the reference electrode may be smaller than the area of ​​the second principal surface.

[0014] This makes it less likely that the reference electrode will come into contact with the solid-state battery portion than when the area of ​​the reference electrode is equal to or greater than the area of ​​the second main surface. For example, even when the reference electrode and the second solid electrolyte layer are pressed against the side surface of the solid-state battery portion to improve contact between the second solid electrolyte layer and the power generating element portion, the reference electrode will be less likely to come into contact with the solid-state battery portion, making it less likely that a short circuit will occur. This makes it possible to achieve a battery with even higher reliability.

[0015] Furthermore, for example, the at least one power generating element unit may be a plurality of power generating element units, the solid-state battery unit may have a structure in which the plurality of power generating element units are stacked, and the structure may further have an exterior body that covers a side surface of the second solid electrolyte layer.

[0016] This allows the second solid electrolyte layer in contact with the solid battery portion to be covered with the exterior body, thereby increasing the mechanical strength of the structure and further improving the reliability of the battery.

[0017] Furthermore, for example, the exterior body may have a surface facing a side surface of the solid-state battery unit, and the second solid electrolyte layer may protrude from the surface.

[0018] This prevents the exterior body from interfering with the side surface of the solid-state battery unit even when the power-generating element unit and the second solid electrolyte layer are in contact with each other, and therefore improves the contact between the power-generating element unit and the second solid electrolyte layer even when the side surface of the solid-state battery unit has minute irregularities, thereby facilitating electrochemical contact between the power-generating element unit and the second solid electrolyte layer.

[0019] Furthermore, for example, the exterior body may include an insulating resin and may be in contact with a side surface of the solid-state battery unit.

[0020] The side surface of the solid-state battery section often has minute irregularities resulting from the materials of each layer of the power generating element section, and the bonding anchor effect between such irregularities and the insulating resin of the exterior body can improve the bonding between the solid-state battery section and the structure, thereby increasing the mechanical strength of the battery and firmly protecting the second solid electrolyte layer by the exterior body, thereby improving the reliability of the battery.

[0021] Also, for example, the outer casing may include a first resin layer containing a first insulating resin and a second resin layer containing a second insulating resin and softer than the first resin layer, and the second resin layer may be located between the first resin layer and the solid-state battery portion and in contact with a side surface of the solid-state battery portion.

[0022] As a result, the second resin layer, which is softer and more easily deformed than the first resin layer, comes into contact with the side surface of the solid battery portion, so that the outer casing is less likely to obstruct contact between the power generating element portion and the second solid electrolyte layer due to deformation of the second resin layer, thereby improving contact between the power generating element portion and the second solid electrolyte layer.In addition, the second resin layer in contact with the side surface of the solid battery portion can also protect the second solid electrolyte layer, thereby improving the reliability of the battery.

[0023] Furthermore, for example, the plurality of power generating element units may be electrically connected in parallel and stacked, and the first main surface may be in contact with two or more of the plurality of power generating element units.

[0024] This allows the first main surface to be enlarged, making it possible to form contact between the power generating element and the second solid electrolyte layer on the side surface of the solid battery portion without precise alignment, thereby facilitating the formation of a battery. Furthermore, the increased contact area between the first main surface and the side surface of the solid battery portion makes it difficult for the second solid electrolyte layer to peel off from the solid battery portion, thereby improving the durability of the battery.

[0025] Furthermore, for example, the exterior body may cover a portion of the second main surface.

[0026] This makes it possible to prevent the reference electrode from spreading even when the reference electrode and the second solid electrolyte layer are pressed against the side surface of the solid battery portion by the exterior body covering part of the second main surface.

[0027] Furthermore, for example, the structure may further include a reference electrode current collector in contact with the reference electrode, and the exterior body may cover the reference electrode and the reference electrode current collector.

[0028] This allows the reference electrode and the reference electrode current collector to be protected by the exterior body, further increasing the mechanical strength of the structure, and therefore further improving the reliability of the battery.

[0029] Furthermore, for example, in a plan view of the side surface of the solid-state battery unit, the structure may not extend beyond both ends of the solid-state battery unit in the stacking direction of the solid-state battery unit.

[0030] As a result, even if the solid state battery section is pressurized in the stacking direction to maintain the performance of the power generating element section, the structure is less likely to interfere with the pressure, and deterioration of the battery characteristics of the solid state battery section can be suppressed.

[0031] Furthermore, for example, the length of the structure in the stacking direction of the solid-state battery unit may be smaller than the length of the solid-state battery unit in the stacking direction of the solid-state battery unit.

[0032] As a result, the structure is positioned more inward than the solid battery section in the stacking direction of the solid battery section, so even if the solid battery section is compressed in the stacking direction when pressure is applied from the stacking direction, the compression of the solid battery section is less likely to be hindered, and the battery characteristics of the solid battery section can be improved.

[0033] Hereinafter, the embodiments will be specifically described with reference to the drawings.

[0034] The embodiments described below are all comprehensive or specific examples. The numerical values, shapes, materials, components, component placement and connection configurations, manufacturing processes, and the order of manufacturing processes shown in the following embodiments are merely examples and are not intended to limit the present disclosure. Furthermore, among the components in the following embodiments, components not described in the independent claims are described as optional components.

[0035] Furthermore, each figure is a schematic diagram and is not necessarily an exact illustration. Therefore, for example, the scales of the figures do not necessarily match. Furthermore, in each figure, substantially the same components are given the same reference numerals, and redundant explanations are omitted or simplified.

[0036] Furthermore, in this specification, terms indicating the relationship between elements, such as parallel or perpendicular, terms indicating the shape of elements, such as rectangular or circular, and numerical ranges are not expressions that only express a strict meaning, but are expressions that also include a substantially equivalent range, for example, a difference of about a few percent.

[0037] In addition, in this specification and drawings, the x-axis, y-axis, and z-axis represent the three axes of a three-dimensional Cartesian coordinate system. The x-axis and y-axis correspond to directions parallel to the main surfaces of the current collectors and each layer included in the solid-state battery section, respectively. The z-axis corresponds to the stacking direction of the multiple power generating element sections included in the solid-state battery section and the stacking direction of each layer included in the power generating element section. Furthermore, unless otherwise specified, the "stacking direction" refers to the direction in which each layer in the solid-state battery section is stacked, and corresponds to the direction normal to the main surfaces of the current collectors and each layer included in the solid-state battery section.

[0038] Furthermore, the "plan view" of a certain surface refers to the surface as viewed from the front.

[0039] In this specification, the terms "upper" and "lower" in the battery configuration do not refer to the upper direction (vertically upper) and lower direction (vertically lower) in absolute spatial recognition, but are used as terms defined by a relative positional relationship based on the stacking order in the stacking configuration. Furthermore, the terms "upper" and "lower" are used not only when two components are arranged closely to each other and are in contact with each other, but also when two components are arranged with a gap between them and another component is present between them.

[0040] (Embodiment) First, the battery according to the embodiment will be described.

[0041] [Battery configuration] First, the configuration of the battery according to this embodiment will be described. FIG. 1 is a cross-sectional view showing a schematic configuration of a battery 500 according to this embodiment. FIG. 2A is a side view showing a schematic configuration of a battery 500 according to this embodiment. FIG. 2A is a plan view of a side surface 100a of a solid battery section 100. FIG. 2B is a side view showing a state in which a reference electrode current collector 170 is removed from the battery 500 shown in FIG. 2A. Note that FIG. 1 shows a cross section taken along line II in FIG. 2A. In addition, in FIGS. 2A and 2B, the shape of a second solid electrolyte layer 130 is indicated by a dashed line.

[0042] 1 and 2A, the battery 500 includes a solid-state battery unit 100 having a plurality of power generating element units 50, and a structure 200 having a second solid electrolyte layer 130, a reference electrode 110, a reference electrode current collector 170, and an exterior body 190. The battery 500 is, for example, an all-solid-state battery. The battery 500 is, for example, a coin-type, laminate-type, cylindrical-type, or prismatic-type battery.

[0043] The solid-state battery unit 100 has a plurality of power generating element units 50, a positive electrode current collector 60, and a negative electrode current collector 70. The solid-state battery unit 100 has a structure in which a plurality of power generating element units 50 are stacked. In the illustrated example, the solid-state battery unit 100 has four power generating element units 50, but there is no limit to the number of power generating element units 50, and the solid-state battery unit 100 only needs to have at least one power generating element unit 50. The shape of the solid-state battery unit 100 is, for example, a rectangular parallelepiped, a polygonal pillar, or a cylindrical shape.

[0044] The side surface 100a of the solid-state battery unit 100 contacts the structure 200. Specifically, the side surface 100a contacts the second solid electrolyte layer 130 and the exterior body 190. The side surface of the solid-state battery unit 100 and each component of the solid-state battery unit 100 is a surface connecting two opposing main surfaces of the solid-state battery unit 100 and each component of the solid-state battery unit 100, and is, for example, a surface parallel to the stacking direction. The side surface 100a may be inclined with respect to the stacking direction.

[0045] The plurality of power generating element units 50 are electrically connected in parallel and stacked. Adjacent power generating element units 50 are stacked with a positive electrode current collector 60 or a negative electrode current collector 70 interposed therebetween. The plurality of power generating element units 50 are stacked so that the same electrode layers of adjacent power generating element units 50 are electrically connected to each other via the current collectors.

[0046] The power generation element unit 50 includes a positive electrode layer 10, an anode layer 20 disposed opposite the positive electrode layer 10, and a first solid electrolyte layer 30 located between the positive electrode layer 10 and the anode layer 20. The positive electrode layer 10 is an example of a first electrode layer, and the anode layer 20 is an example of a second electrode layer. In the power generation element unit 50, the positive electrode layer 10, the first solid electrolyte layer 30, and the anode layer 20 are stacked in this order. The shape of the power generation element unit 50 is, for example, a rectangular parallelepiped, a polygonal pillar, or a cylindrical shape.

[0047] The multiple power generating element units 50 are stacked such that the arrangement directions of the layers of adjacent power generating element units 50 are reversed. Therefore, in adjacent power generating element units 50, the positive electrode layers 10 or the negative electrode layers 20 face each other without the first solid electrolyte layer 30 interposed therebetween.

[0048] In each of the multiple power generation element units 50, a positive electrode current collector 60 is laminated on the main surface of the positive electrode layer 10 opposite the first solid electrolyte layer 30, and a negative electrode current collector 70 is laminated on the main surface of the negative electrode layer 20 opposite the first solid electrolyte layer 30. Two positive electrode current collectors 60 are disposed between adjacent power generation element units 50, each stacked so that the positive electrode layers 10 face each other without the first solid electrolyte layer 30 interposed therebetween. Two negative electrode current collectors 70 are disposed between adjacent power generation element units 50, each stacked so that the negative electrode layers 20 face each other without the first solid electrolyte layer 30 interposed therebetween. This electrically connects the same electrode layers of adjacent power generation element units 50. The number of positive electrode current collectors 60 and negative electrode current collectors 70 disposed between adjacent power generation element units 50 is not limited to two and may be one. That is, the positive electrode layers 10 may be laminated on both main surfaces of one positive electrode current collector 60, and the negative electrode layers 20 may be laminated on both main surfaces of one negative electrode current collector 70.

[0049] Furthermore, the positive electrode current collector 60, the negative electrode current collector 70, and the power generation element section 50 located between the positive electrode current collector 60 and the negative electrode current collector 70 constitute a unit battery cell 80. In other words, the unit battery cell 80 has the positive electrode current collector 60, the negative electrode current collector 70, and the power generation element section 50. Therefore, the solid-state battery section 100 has a structure in which a plurality of unit battery cells 80 are stacked such that the same poles of adjacent unit battery cells 80 are connected to each other. As a result, the plurality of unit battery cells 80 are stacked while electrically connected in parallel.

[0050] The positive electrode layer 10 is located between the positive electrode current collector 60 and the first solid electrolyte layer 30, and is in contact with the positive electrode current collector 60 and the first solid electrolyte layer 30. The side surface of the positive electrode layer 10 facing the structure 200 is in contact with the second solid electrolyte layer 130, specifically, the first main surface 130a.

[0051] The positive electrode layer 10 includes at least a positive electrode active material. As a material for the positive electrode layer 10, a positive electrode mixture including at least one of a solid electrolyte, a conductive additive, and a binder material may be used in addition to the positive electrode active material, as needed.

[0052] As the positive electrode active material, known materials that can occlude and release (insert and desorb, or dissolve and deposit) metal ions such as lithium ions, sodium ions, magnesium ions, potassium ions, calcium ions, or copper ions can be used.

[0053] Examples of the positive electrode active material include lithium-containing transition metal oxides, lithium-free transition metal oxides, transition metal fluorides, polyanion materials, fluorinated polyanion materials, transition metal sulfides, transition metal oxyfluorides, transition metal oxysulfides, and transition metal oxynitrides. When a lithium-containing transition metal oxide is used as the positive electrode active material, the manufacturing cost of the battery can be reduced and the average discharge voltage of the battery can be increased.

[0054] As the positive electrode active material, in the case of a material capable of extracting and inserting lithium ions, for example, lithium cobalt oxide composite oxide (LCO), lithium nickel oxide composite oxide (LNO), lithium manganese oxide composite oxide (LMO), lithium-manganese-nickel composite oxide (LMNO), lithium-manganese-cobalt composite oxide (LMCO), lithium-nickel-cobalt composite oxide (LNCO), or lithium-nickel-manganese-cobalt composite oxide (LNMCO) can be used. Specific positive electrode active materials include, for example, LiCoO2, LiMn2O4, Li2NiMn3O8, LiVO2, LiCrO2, LiFePO4, LiCoPO4, LiNiO2, and LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2, LiNi x Mn y Al z O2, LiNi x Co y Mn z and LiNi x Co y Al z etc.

[0055] The solid electrolyte may be a known material that conducts metal ions such as lithium ions, sodium ions, magnesium ions, potassium ions, calcium ions, copper ions, or silver ions, or protons, etc. Examples of the solid electrolyte include solid electrolyte materials such as sulfide solid electrolytes, halogen-based solid electrolytes, oxide solid electrolytes, and polymer solid electrolytes.

[0056] As a sulfide solid electrolyte, in the case of a material capable of conducting lithium ions, for example, a compound (Li2S-P2S5) consisting of lithium sulfide (Li2S) and diphosphorus pentasulfide (P2S5) is used. In addition, examples of sulfide solid electrolytes include Li2S-P2S5, Li2S-P2S5-LiBH4, and Li7P3S 11 , Li2S-SiS2, Li2S-SiS2-Li3PO4, Li2S-SiS2-Li4SiO4, Li2S-B2S3, Li2S-GeS2, Li6PS5Cl, LiSiPSCl, and sulfides containing Li3N or Li3N(H). In addition, as the sulfide solid electrolyte, a sulfide obtained by adding at least one of Li3N, LiCl, LiBr, LiI, Li3PO4, and Li4SiO4 to the above sulfides as an additive may be used. In addition, other specific sulfide solid electrolytes include Li 10 GeP2S 12 (LGPS), Na3Zr2(SiO4)2PO4(NASICON), etc.

[0057] As an oxide solid electrolyte, materials that can conduct lithium ions include, for example, Li7La3Zr2O 12 (LLZ), Li 1.3 Al 0.3 Ti 1.7 (PO4)3(LATP) or (La,Li)TiO3(LLTO) are used.

[0058] A halogen-based solid electrolyte is a solid electrolyte containing a halide. The halide is, for example, a compound consisting of Li, M', and X'. M' is at least one element selected from the group consisting of metal elements and metalloid elements other than Li. X' is at least one element selected from the group consisting of F, Cl, Br, and I. "Metal element" refers to all elements contained in Groups 1 to 12 of the periodic table (excluding hydrogen) and all elements contained in Groups 13 to 16 of the periodic table (excluding B, Si, Ge, As, Sb, Te, C, N, P, O, S, and Se). "Metalloid element" refers to B, Si, Ge, As, Sb, and Te. For example, M' may contain Y (yttrium). Examples of halides containing Y include Li3YCl6 and Li3YBr6.

[0059] Other halides include, for example, Li2MgX'4, Li2FeX'4, Li(Al,Ga,In)X'4, Li3(Al,Ga,In)X'6, LiOX', and LiX'. Specifically, halides include, for example, Li3InBr6, Li3InCl6, Li2FeCl4, Li2CrCl4, Li3OCl, and LiI.

[0060] The polymer solid electrolyte is not particularly limited as long as it is a solid electrolyte containing a polymer material having ion conductivity. Examples of the polymer material having ion conductivity include polyether, polyether derivatives, polyester, and polyimine.

[0061] In addition to the above-mentioned solid electrolyte materials, a thin-film solid electrolyte material such as nitrogen-doped lithium phosphate (LIPON) may also be used as the solid electrolyte.

[0062] In the positive electrode layer 10, the volume ratio of the positive electrode active material to the total volume of the positive electrode active material and the solid electrolyte is, for example, 30% or more and 95% or less. Furthermore, the volume ratio of the solid electrolyte to the total volume of the positive electrode active material and the solid electrolyte is, for example, 5% or more and 70% or less. When the amount of the positive electrode active material and the amount of the solid electrolyte are in such a volume ratio, it becomes easier to ensure a sufficient energy density of the battery 500 and to operate the battery 500 at high output.

[0063] The binder material may be the same as that used in general solid-state batteries, and examples of the binder material include polyvinylidene fluoride, polytetrafluoroethylene, polyethylene, polypropylene, aramid resin, polyamide, polyimide, polyamideimide, polyacrylonitrile, polyallylic acid, polymethyl acrylate, polyethyl acrylate, polyhexyl acrylate, polymethacrylic acid, polymethyl methacrylate, polyethyl methacrylate, polyhexyl methacrylate, polyvinyl acetate, polyvinylpyrrolidone, polyether, polyethersulfone, hexafluoropolypropylene, styrene-butadiene rubber, carboxymethyl cellulose, polyaniline, polythiophene-styrene-butadiene rubber, and polyacrylate. Furthermore, as the binder material, a copolymer of two or more materials selected from tetrafluoroethylene, hexafluoroethylene, hexafluoropropylene, perfluoroalkyl vinyl ether, vinylidene fluoride, chlorotrifluoroethylene, ethylene, propylene, pentafluoropropylene, fluoromethyl vinyl ether, acrylic acid, and hexadiene may be used.

[0064] Examples of conductive additives include graphite such as natural graphite and artificial graphite, carbon black such as acetylene black, furnace black, and Ketjen Black (registered trademark), conductive fibers such as VGCF, carbon nanotubes, carbon nanofibers, fullerenes, carbon fibers, and metal fibers, metal powders such as carbon fluoride and aluminum powder, conductive whiskers such as zinc oxide whiskers and potassium titanate whiskers, conductive metal oxides such as titanium oxide, and conductive polymer compounds such as polyaniline, polypyrrole, and polythiophene.

[0065] The conductive additive may have a shape of, for example, a needle, a scale, a sphere, or an oval sphere. The conductive additive may also be in the form of particles.

[0066] The thickness of the positive electrode layer 10 is, for example, 10 μm or more and 500 μm or less. When the thickness of the positive electrode layer 10 is in this range, it becomes easier to ensure a sufficient energy density of the battery 500 and to operate the battery 500 at high output. In this specification, the thickness of each component of the solid-state battery section 100 is the length of each component in the stacking direction.

[0067] Examples of methods for forming the positive electrode layer 10 include uniaxial compression molding of a powdered positive electrode mixture. Alternatively, the positive electrode layer 10 may be produced by applying a paste-like paint, in which the positive electrode mixture is kneaded with a solvent, onto the substrate, the first solid electrolyte layer 30, the positive electrode current collector 60, or the like, and drying the paint.

[0068] The anode layer 20 is located between the anode current collector 70 and the first solid electrolyte layer 30, and is in contact with the anode current collector 70 and the first solid electrolyte layer 30. The side surface of the anode layer 20 facing the structure 200 is in contact with the second solid electrolyte layer 130, specifically, the first main surface 130a.

[0069] The negative electrode layer 20 includes at least a negative electrode active material. As a material for the negative electrode layer 20, in addition to the negative electrode active material, a negative electrode mixture including at least one of a solid electrolyte, a conductive additive, and a binder material may be used as needed.

[0070] The negative electrode active material may be a known material capable of occluding and releasing (inserting and desorbing, or dissolving and depositing) metal ions such as lithium ions, sodium ions, magnesium ions, potassium ions, calcium ions, or copper ions. Examples of the negative electrode active material include metal materials, carbon materials, oxides, nitrides, tin compounds, and silicon compounds.

[0071] As the negative electrode active material, materials capable of extracting and inserting lithium ions are used, such as carbon materials such as natural graphite, artificial graphite, graphite carbon fiber, and resin-baked carbon, metallic lithium, lithium alloys, and oxides of lithium and transition metal elements. Metals used in lithium alloys include indium, aluminum, silicon, germanium, tin, and zinc. Specific examples of oxides of lithium and transition metal elements include Li4Ti5O 12 and Li x SiO and the like.

[0072] The above-described solid electrolyte material can be used as the solid electrolyte of the anode layer 20. The above-described conductive additive can be used as the conductive additive of the anode layer 20. The above-described binder material can be used as the binder material of the anode layer 20.

[0073] In the negative electrode layer 20, the volume ratio of the negative electrode active material to the total volume of the negative electrode active material and the solid electrolyte is, for example, 30% or more and 95% or less. Furthermore, the volume ratio of the solid electrolyte to the total volume of the negative electrode active material and the solid electrolyte is, for example, 5% or more and 70% or less. When the amount of the negative electrode active material particles and the amount of the solid electrolyte are in such a volume ratio, the energy density of the battery 500 can be sufficiently ensured, and the battery 500 can be easily operated at high output.

[0074] The thickness of the negative electrode layer 20 is, for example, 10 μm or more and 500 μm or less. When the thickness of the negative electrode layer 20 is in this range, it becomes easier to ensure a sufficient energy density of the battery 500 and to operate the battery 500 at high output.

[0075] Examples of methods for forming the negative electrode layer 20 include uniaxial compression molding of a powdered negative electrode mixture. Alternatively, the negative electrode layer 20 may be produced by applying a paste-like paint, in which the negative electrode mixture is kneaded with a solvent, onto the substrate, the first solid electrolyte layer 30, the negative electrode current collector 70, or the like, and drying the resulting paint.

[0076] The first solid electrolyte layer 30 is located between the positive electrode layer 10 and the negative electrode layer 20, and is in contact with the positive electrode layer 10 and the negative electrode layer 20. The side surface of the first solid electrolyte layer 30 facing the structure 200 is in contact with the second solid electrolyte layer 130, specifically, the first main surface 130a.

[0077] The first solid electrolyte layer 30 has conductivity of metal ions such as lithium ions, sodium ions, magnesium ions, potassium ions, calcium ions, or copper ions. The first solid electrolyte layer 30 may also have lithium ion conductivity.

[0078] The first solid electrolyte layer 30 contains at least a solid electrolyte and may contain a binder material as needed. The first solid electrolyte layer 30 may also contain a solid electrolyte having lithium ion conductivity.

[0079] The above-mentioned solid electrolyte materials can be used as the solid electrolyte of the first solid electrolyte layer 30. One type of solid electrolyte or two or more types of solid electrolytes can be used for the first solid electrolyte layer 30. The above-mentioned binder materials can be used as the binder material of the first solid electrolyte layer 30.

[0080] The thickness of the first solid electrolyte layer 30 is, for example, 0.1 μm or more and 1000 μm or less. From the viewpoint of improving the energy density of the battery 500, the thickness of the first solid electrolyte layer 30 may be 0.1 μm or more and 50 μm or less.

[0081] Examples of methods for forming the first solid electrolyte layer 30 include uniaxial compression molding of a powder of the material containing the first solid electrolyte layer 30. Alternatively, the first solid electrolyte layer 30 may be produced by applying a paste-like paint, in which the material containing the first solid electrolyte layer 30 is kneaded with a solvent, onto the substrate, the positive electrode layer 10, the negative electrode layer 20, or the like, and drying the paint.

[0082] The side surfaces of the positive electrode layer 10, the negative electrode layer 20, and the first solid electrolyte layer 30 are flush with each other and form the side surfaces of the power generation element section 50. Note that the side surfaces of the positive electrode layer 10, the negative electrode layer 20, and the first solid electrolyte layer 30 do not have to be flush with each other. For example, the first solid electrolyte layer 30 may cover the side surfaces of the positive electrode layer 10 and the negative electrode layer 20, and the side surfaces of the power generation element section 50 may be formed only by the side surfaces of the first solid electrolyte layer 30.

[0083] The positive electrode current collector 60 is located on the opposite side of the positive electrode layer 10 from the first solid electrolyte layer 30 side, and is in contact with the positive electrode layer 10. The negative electrode current collector 70 is located on the opposite side of the negative electrode layer 20 from the first solid electrolyte layer 30 side, and is in contact with the negative electrode layer 20.

[0084] Examples of materials for the positive electrode current collector 60 and the negative electrode current collector 70 include highly conductive metal materials such as copper, aluminum, nickel, iron, stainless steel, platinum, gold, an alloy of two or more of these, or a plated version of any of these. The positive electrode current collector 60 and the negative electrode current collector 70 may be made of the same material or different materials.

[0085] There are no particular limitations on the shapes of the positive electrode current collector 60 and the negative electrode current collector 70, as they may be set according to the shape of the battery 500. The shapes of the positive electrode current collector 60 and the negative electrode current collector 70 are, for example, rod-like, plate-like, sheet-like, foil-like, mesh-like, or the like.

[0086] The thickness of the positive electrode current collector 60 and the negative electrode current collector 70 is, for example, 1 μm or more and 10 mm or less. The thickness of the positive electrode current collector 60 and the negative electrode current collector 70 may be 1 μm or more and 50 μm or less. Depending on the shape of the battery 500, the thickness of the positive electrode current collector 60 and the negative electrode current collector 70 may be 10 mm or more.

[0087] The positive electrode layer 10, the negative electrode layer 20, the first solid electrolyte layer 30, the positive electrode current collector 60, and the negative electrode current collector 70 each have a planar shape that is, for example, rectangular, circular, or polygonal. When viewed from the stacking direction, for example, the outer edges of the positive electrode layer 10, the negative electrode layer 20, the first solid electrolyte layer 30, the positive electrode current collector 60, and the negative electrode current collector 70 coincide. However, when viewed from the stacking direction, the outer edges of the positive electrode layer 10, the negative electrode layer 20, the first solid electrolyte layer 30, the positive electrode current collector 60, and the negative electrode current collector 70 do not necessarily have to coincide.

[0088] The structure 200 is provided so as to cover the side surface 100a of the solid-state battery unit 100. When the solid-state battery unit 100 has a rectangular parallelepiped shape, the structure 200 covers, for example, only one side surface 100a of the four side surfaces of the solid-state battery unit 100.

[0089] In a plan view of the side surface 100a of the solid-state battery unit 100, the structure 200 does not protrude beyond both ends of the solid-state battery unit 100 in the stacking direction of the solid-state battery unit 100. In the present embodiment, in a plan view of the side surface 100a, the outermost periphery of the structure 200 is formed by the exterior body 190, and the exterior body 190 does not protrude beyond both ends of the solid-state battery unit 100 in the stacking direction of the solid-state battery unit 100. The length of the structure 200 in the stacking direction of the solid-state battery unit 100 is equal to or less than the length of the solid-state battery unit 100 in the stacking direction of the solid-state battery unit 100. As a result, even when the solid-state battery unit 100 is used while being pressurized in the stacking direction to maintain battery characteristics, the structure 200 is less likely to interfere with the pressure applied to the solid-state battery unit 100, and the pressurized state of the solid-state battery unit 100 is easily maintained. Furthermore, deformation of the structure 200 due to the pressure applied to the solid-state battery unit 100 is suppressed, thereby improving the reliability of the battery 500. In this embodiment, the length of the structure 200 in the stacking direction of the solid-state battery units 100 is the same as the length of the solid-state battery units 100 in the stacking direction of the solid-state battery units 100.

[0090] The structure 200 includes a second solid electrolyte layer 130, a reference electrode 110, a reference electrode current collector 170, and an exterior body 190. The second solid electrolyte layer 130, the reference electrode 110, and the reference electrode current collector 170 are arranged in this order along the normal direction of the side surface 100a, and away from the side surface 100a.

[0091] The shape of the structure 200 is, for example, a rectangular parallelepiped, but it may also be a cylindrical or polygonal prism, or may be curved to match the shape of the solid-state battery section 100. Furthermore, a convex portion or a concave portion may be formed on part of the surface of the structure 200.

[0092] The second solid electrolyte layer 130 is located between the reference electrode 110 and the solid battery unit 100. The second solid electrolyte layer 130 is surrounded by an exterior body 190 in a plan view of the side surface 100a of the solid battery unit 100.

[0093] The second solid electrolyte layer 130 has a first main surface 130a in contact with the power generating element 50 and a second main surface 130b opposite to the first main surface 130a on the side surface 100a of the solid battery section 100. The first main surface 130a and the second main surface 130b are main surfaces facing back to back to each other. Furthermore, the side surface 100a, the first main surface 130a, and the second main surface 130b are, for example, parallel to each other.

[0094] The first main surface 130a contacts two or more of the multiple power generating element units 50, for example, at the side surface 100a. In the illustrated example, the first main surface 130a contacts two adjacent power generating element units 50. This improves the mechanical strength of the second solid electrolyte layer 130 and the bonding strength between the second solid electrolyte layer 130 and the solid battery unit 100, thereby improving the reliability of the battery 500. The length of the first main surface 130a in the stacking direction is, for example, more than twice the thickness of the power generating element unit 50. Note that the first main surface 130a may contact only one of the multiple power generating element units 50. Furthermore, in the example shown in FIG. 1, the first main surface 130a is provided so as to contact the entire power generating element unit 50 in the stacking direction, but it may also contact only a portion of the power generating element unit 50 in the stacking direction. For example, the first main surface 130a may be in contact with at least one of the positive electrode layer 10, the first solid electrolyte layer 30, and the negative electrode layer 20 in the power generating element section 50.

[0095] Specifically, the first main surface 130a is in contact with all of the side surfaces of the positive electrode layer 10, the negative electrode layer 20, and the first solid electrolyte layer 30 that constitute the power generation element section 50, facing the structure 200. The first main surface 130a may also be in contact with at least one of the positive electrode current collector 60 and the negative electrode current collector 70. In the example shown, the first main surface 130a is in contact with the positive electrode current collector 60 that is located between the two power generation element sections 50 that are in contact with the first main surface 130a. It is sufficient that the first main surface 130a is in contact with at least a portion of the power generation element section 50 at the side surface 100a.

[0096] In addition, in a plan view of the side surface 100a, the width of the second solid electrolyte layer 130 is smaller than the width of the power generation element section 50, and the second solid electrolyte layer 130 is located more inward than both ends of the power generation element section 50 in the width direction. Here, the "width" refers to the length in a direction perpendicular to the stacking direction in a plan view of the side surface 100a. Note that in a plan view of the side surface 100a, both ends of the second solid electrolyte layer 130 in the width direction may coincide with both ends of the power generation element section 50 in the width direction.

[0097] The second main surface 130b contacts the reference electrode 110. The second main surface 130b may also contact the exterior body 190.

[0098] The second solid electrolyte layer 130 may be made of the same material as the first solid electrolyte layer 30. The first solid electrolyte layer 30 and the second solid electrolyte layer 130 may be made of the same material or different materials. The second solid electrolyte layer 130 may be made of one type of solid electrolyte or two or more types of solid electrolytes.

[0099] The thickness of the second solid electrolyte layer 130 is, for example, 10 μm or more and 10 mm or less. The thickness of the second solid electrolyte layer 130 is, for example, greater than the thickness of the first solid electrolyte layer 30. In this specification, the thickness of each component of the structure 200 is the length of each component in the normal direction to the side surface 100 a of the solid battery section 100.

[0100] The reference electrode 110 faces the side surface 100a with the second solid electrolyte layer 130 interposed therebetween. The reference electrode 110 contacts the second main surface 130b of the second solid electrolyte layer 130. This allows the reference electrode 110 to be ionically connected to the positive electrode layer 10 and the negative electrode layer 20 via the second solid electrolyte layer 130, and therefore the electrical characteristics of the positive electrode layer 10 and the negative electrode layer 20 can be measured using the reference electrode 110. The reference electrode 110 is surrounded by an exterior body 190 in a plan view of the side surface 100a of the solid battery unit 100.

[0101] As shown in FIG. 2B, the area of ​​the reference electrode 110 is smaller than the area of ​​the second main surface 130b in a plan view relative to the second main surface 130b. The area of ​​the reference electrode 110 in a plan view relative to the second main surface 130b is the area of ​​a region surrounded by the outer edge of the reference electrode 110 in a plan view relative to the second main surface 130b. Furthermore, in a plan view relative to the second main surface 130b, the reference electrode 110 is located inside the outer edge of the second main surface 130b. In other words, in a plan view relative to the second main surface 130b, the entire reference electrode 110 is provided on a partial region of the second main surface 130b and is located inside the second main surface 130b. In FIG. 2B, the outer edge of the second main surface 130b is the portion indicated by the dashed rectangle. This makes it less likely that the reference electrode 110 will come into contact with the solid-state battery unit 100, compared to when the area of ​​the reference electrode 110 is equal to or greater than the area of ​​the second main surface 130b, and suppresses short-circuiting between the reference electrode 110 and the solid-state battery unit 100. For example, even when the reference electrode 110 and the second solid electrolyte layer 130 are pressed against the solid-state battery unit 100 to improve contact between the second solid electrolyte layer 130 and the power generating element unit 50, the reference electrode 110 is prevented from protruding from the second main surface 130b and coming into contact with the solid-state battery unit 100 due to the pressing force.

[0102] 2B, the reference electrode 110 is not in contact with the outer edge of the second main surface 130b in a plan view relative to the second main surface 130b. Note that the reference electrode 110 may be in contact with part of the outer edge of the second main surface 130b as long as it does not extend beyond the outer edge of the second main surface 130b in a plan view relative to the second main surface 130b.

[0103] The material of the reference electrode 110 is not particularly limited as long as it is in electrochemical contact with the second solid electrolyte layer 130 and exhibits an equilibrium potential. The reference electrode 110 includes, for example, at least one of metallic lithium, a lithium alloy, and a lithium compound. From the viewpoint of measurement accuracy, a material with a small fluctuation in equilibrium potential may be used as the material of the reference electrode 110. Examples of materials with a small fluctuation in equilibrium potential include metallic lithium, lithium alloys such as In-Li, and Li4Ti5O 12Examples of lithium compounds include:

[0104] Although the structure 200 has one second solid electrolyte layer 130 and one reference electrode 110, this is not limiting. At least one of the second solid electrolyte layer 130 and the reference electrode 110 in the structure 200 may be plural. For example, the structure 200 may have plural second solid electrolyte layers 130. For example, the plural second solid electrolyte layers 130 are arranged so as to be in contact with different power generating element parts 50 among the plural power generating element parts 50. In this case, the reference electrode 110 in contact with the plural second solid electrolyte layers 130 may be individual or may be shared.

[0105] The reference electrode current collector 170 is located on the side of the reference electrode 110 opposite to the second solid electrolyte layer 130 side, and is in contact with the reference electrode 110. The reference electrode current collector 170 covers, for example, the entire surface of the reference electrode 110 opposite to the second solid electrolyte layer 130 side. The position at which the reference electrode current collector 170 is in contact with the reference electrode 110 is not particularly limited, and the reference electrode current collector 170 may be in contact with any surface of the reference electrode 110 other than the surface that is in contact with the second solid electrolyte layer 130.

[0106] The surface of the reference electrode current collector 170 opposite to the reference electrode 110 side is exposed to the outside and is connected to, for example, a terminal or the like for extracting current. Note that the structure 200 does not necessarily have to have the reference electrode current collector 170, and for example, the electrical characteristics may be measured by directly contacting a terminal or the like with the reference electrode 110.

[0107] In a plan view of the side surface 100a, the outer edge of the reference electrode current collector 170 coincides with the outer edge of the reference electrode 110. In other words, in a plan view of the side surface 100a, the reference electrode current collector 170 and the reference electrode 110 have the same size. Note that, in a plan view of the side surface 100a, the reference electrode current collector 170 and the reference electrode 110 may have different sizes; for example, the reference electrode current collector 170 may be larger than the reference electrode 110.

[0108] Examples of materials for the reference electrode current collector 170 include highly conductive metal materials such as copper, aluminum, nickel, iron, stainless steel, platinum, or gold, an alloy of two or more of these, or a plated version of any of these.

[0109] The shape of the reference electrode current collector 170 is not particularly limited, as it may be set according to the shape of the structure 200. The shape of the reference electrode current collector 170 is, for example, a rod, plate, sheet, foil, or mesh.

[0110] The thickness of the reference electrode current collector 170 is, for example, 1 μm or more and 20 mm or less. The thickness of the reference electrode current collector 170 is also, for example, greater than the thicknesses of the second solid electrolyte layer 130 and the reference electrode 110. Depending on the shapes of the battery 500 and the structure 200, the thickness of the reference electrode current collector 170 may be 10 mm or more.

[0111] In a plan view of the side surface 100a, the second solid electrolyte layer 130, the reference electrode 110, and the reference electrode current collector 170 each have a shape that is, for example, rectangular, circular, or polygonal.

[0112] The exterior body 190 covers the side surface of the second solid electrolyte layer 130, which is a surface connecting the outer edge of the first main surface 130a and the outer edge of the second main surface 130b. The exterior body 190 is in contact with the side surface of the second solid electrolyte layer 130. The side surface of each component of the structure 200 is, for example, a surface parallel to the normal direction of the side surface 100a of the solid battery unit 100. The exterior body 190 does not cover the first main surface 130a. In a plan view of the side surface 100a of the solid battery unit 100, the exterior body 190 surrounds the second solid electrolyte layer 130. Note that, although the exterior body 190 surrounds the entire periphery of the second solid electrolyte layer 130 in a plan view of the side surface 100a of the solid battery unit 100, this is not limiting. The exterior body 190 may be arranged, for example, so as to surround the second solid electrolyte layer 130 from both sides in at least a predetermined direction in a plan view of the side surface 100a of the solid battery unit 100. When the shape of the second solid electrolyte layer 130 in a plan view is rectangular, the exterior body 190 may surround the second solid electrolyte layer 130 so as to cover, for example, only two opposing sides of the second solid electrolyte layer 130, or only two opposing sides and one other side. The exterior body 190 may be arranged, for example, so as to sandwich the second solid electrolyte layer 130 from both sides in the stacking direction of the solid battery unit 100.

[0113] The exterior body 190 also covers a portion of the second main surface 130b. The exterior body 190 is in contact with a portion of the second main surface 130b that is not in contact with the reference electrode 110. As a result, even when the reference electrode 110 and the second solid electrolyte layer 130 are pressed against the side surface 100a, the exterior body 190 covering the second main surface 130b can prevent the reference electrode 110 from spreading, thereby preventing contact between the reference electrode 110 and the solid state battery section 100. Note that the exterior body 190 does not have to cover the second main surface 130b, and a gap may be provided between the exterior body 190 and the reference electrode 110.

[0114] The exterior body 190 also covers the reference electrode 110 and the reference electrode current collector 170. The exterior body 190 is in contact with the reference electrode 110 and the reference electrode current collector 170. In a plan view of the side surface 100a of the solid-state battery section 100, the exterior body 190 surrounds the reference electrode 110 and the reference electrode current collector 170. This allows the reference electrode 110 and the reference electrode current collector 170 to be protected by the exterior body 190, further increasing the mechanical strength of the structure 200. This further improves the reliability of the battery 500. The exterior body 190 does not necessarily have to cover at least one of the reference electrode 110 and the reference electrode current collector 170.

[0115] The exterior body 190 covers the side surface 100a of the solid-state battery unit 100 and is in contact with the side surface 100a. For example, the exterior body 190 continuously covers the side surface 100a from one end to the other end in the stacking direction. Note that the exterior body 190 does not necessarily have to cover at least one of the one end and the other end of the side surface 100a in the stacking direction.

[0116] The exterior body 190 has a surface 190a that faces the side surface 100a. The surface 190a is in contact with the side surface 100a. The surface 190a is also flush with the first main surface 130a, for example.

[0117] In the exterior body 190, at least the portion that contacts the solid-state battery unit 100, in other words, the portion including the surface 190a, is made of an insulating material such as insulating resin or ceramic. In the exterior body 190, the portion that does not contact the solid-state battery unit 100 may be made of the same material as the portion that contacts the solid-state battery unit 100, or may be made of a different material. When the portion that does not contact the solid-state battery unit 100 is made of a different material from the portion that contacts the solid-state battery unit 100, it may be made of a material that is stronger than the portion that contacts the solid-state battery unit 100. Furthermore, the portion that does not contact the solid-state battery unit 100 may be made of a conductive material such as a metal material. In this case, the exterior body 190 can also function as a current collector for the reference electrode 110.

[0118] The insulating material used for the exterior body 190 includes, for example, an insulating resin as a main component. The insulating material may further include various resin additives. Examples of insulating resins include epoxy resin, silicone resin, polycarbonate resin, polybutadiene resin, acrylic resin, polyamide resin, and polyacetal resin. The insulating resin may be a thermoplastic resin, a thermosetting resin, or a photocurable resin. The side surface 100a of the solid-state battery module 100 has fine irregularities derived from the materials of each layer of the power generating element module 50. When the exterior body 190 includes an insulating resin, the bonding anchor effect between the irregularities and the insulating resin of the exterior body 190 can improve the bonding between the solid-state battery module 100 and the structure 200. This increases the mechanical strength of the battery 500, and the second solid electrolyte layer 130 is firmly protected by the exterior body 190, thereby improving the reliability of the battery 500.

[0119] [Battery manufacturing method] Next, a method for manufacturing the battery 500 according to this embodiment will be described. Note that the method for manufacturing the battery 500 is not limited to the following example.

[0120] The battery 500 can be manufactured, for example, by separately manufacturing the solid-state battery section 100 and the structure 200 and pressing the structure 200 against the side surface 100a of the solid-state battery section 100.

[0121] First, the solid-state battery unit 100 is fabricated. The solid-state battery unit 100 can be fabricated using a method similar to that used to fabricate a general battery. For example, first, powders of materials constituting the positive electrode layer 10, the first solid electrolyte layer 30, and the negative electrode layer 20 are sequentially compressed and compression-molded to fabricate the power generating element unit 50. Next, a positive electrode current collector 60 is stacked so as to contact the positive electrode layer 10 of the power generating element unit 50, and a negative electrode current collector 70 is stacked so as to contact the negative electrode layer 20 of the power generating element unit 50. A plurality of unit battery cells 80, which are power generating element units 50 each having such current collectors stacked thereon, are fabricated. The solid-state battery unit 100 is fabricated by stacking these unit battery cells 80 so as to be electrically connected in parallel. Note that the solid-state battery unit 100 may be fabricated by a method other than the above, as long as the power generating element unit 50 and the current collectors are stacked.

[0122] Next, the structure 200 is fabricated. Specifically, first, an exterior body 190 having openings for forming the second solid electrolyte layer 130 and the like is prepared. Next, the material constituting the second solid electrolyte layer 130 is compressed and compression-molded into the opening of the exterior body 190 to form the second solid electrolyte layer 130. The reference electrode 110 is disposed on the second main surface 130b of the formed second solid electrolyte layer 130, or the material constituting the reference electrode 110 is compressed and compression-molded. Furthermore, the reference electrode current collector 170 is disposed on the formed reference electrode 110 to fabricate the structure 200. Note that the fabrication of the structure 200 is not limited to the above method. For example, the structure 200 may be fabricated by forming the exterior body 190 by sandwiching a stack of the second solid electrolyte layer 130, the reference electrode 110, and the reference electrode current collector 170 between insulating resin sheets or the like.

[0123] Next, the first main surface 130a of the second solid electrolyte layer 130 of the structure 200 is pressed against the side surface 100a of the solid battery section 100, and the first main surface 130a is brought into contact with the power generating element section 50, thereby manufacturing the battery 500.

[0124] In another manufacturing method, after the solid battery unit 100 is fabricated by the method described above or the like, the second solid electrolyte layer 130 is formed on the side surface 100a so as to be in contact with the power generating element unit 50, and the reference electrode 110 is formed on the second main surface 130b of the formed second solid electrolyte layer 130. Furthermore, the reference electrode current collector 170 is placed on the formed reference electrode 110. Next, an insulating resin or the like is applied to the side surface 100a of the solid battery unit 100 to form an exterior body 190 so as to surround and cover the second solid electrolyte layer 130, the reference electrode 110, and the reference electrode current collector 170. In this manner, the battery 500 may be manufactured by fabricating the structure 200 directly on the side surface 100a.

[0125] In this manufacturing method, the bonding anchor effect between the insulating resin and the fine irregularities on the side surface 100a of the solid battery section 100, which are derived from the constituent materials of each layer of the power generating element section 50, improves the bonding between the structure 200 and the solid battery section 100. As a result, the second solid electrolyte layer 130 and the power generating element section 50 can form and maintain firm electrochemical contact.

[0126] [Method for measuring the electrical characteristics of batteries] Next, a method for measuring the electrical characteristics of the battery 500 according to this embodiment will be described. Specifically, a method for measuring the electrical characteristics of the battery 500 including the power generating element section 50 will be described with reference to Figs. 3A and 3B.

[0127] 3A and 3B are diagrams for explaining a method for measuring the electrical characteristics of battery 500. FIG.

[0128] As shown in FIG. 3A, first, a solid-state battery unit 100 and a structure 200 are prepared, in which a plurality of power generating element units 50 are stacked, using the manufacturing method described above or the like. Then, on the side surface 100a of the solid-state battery unit 100, the first main surface 130a of the second solid electrolyte layer 130 is brought into contact with at least one power generating element unit 50. For example, by pressing the structure 200 against the side surface 100a of the solid-state battery unit 100, the first main surface 130a of the second solid electrolyte layer 130 is brought into contact with at least one power generating element unit 50. As a result, a battery 500 is formed, as shown in FIG. 3B.

[0129] 3B, for example, a voltage measuring device 91 is electrically connected to the positive electrode layer 10 and the negative electrode layer 20 in one of the power generating element units 50 that is in contact with the first main surface 130a of the second solid electrolyte layer 130 via a positive electrode current collector 60 and a negative electrode current collector 70. A voltage measuring device 92 is electrically connected to the positive electrode layer 10 and the reference electrode 110 via a positive electrode current collector 60 and a reference electrode current collector 170. A voltage measuring device 93 is electrically connected to the negative electrode layer 20 and the reference electrode 110 via a negative electrode current collector 70 and a reference electrode current collector 170. This makes it possible to measure the voltage V1 between the positive electrode layer 10 and the negative electrode layer 20, the voltage V2 between the positive electrode layer 10 and the reference electrode 110, and the voltage V3 between the negative electrode layer 20 and the reference electrode 110. In this manner, electrical characteristics such as the voltage between at least one of the positive electrode layer 10 and the negative electrode layer 20 and the reference electrode 110 are measured. Furthermore, as the electrical characteristic, an electrical characteristic other than voltage, such as impedance, may be measured.

[0130] At this time, regardless of the operation of the positive electrode layer 10 and the negative electrode layer 20, the reference electrode 110 exhibits a constant value as an equilibrium potential between itself and the second solid electrolyte layer 130, and therefore the potential of the positive electrode layer 10 and / or the negative electrode layer 20 can be measured as the voltage difference between the reference electrode 110 and the positive electrode layer 10 and / or the negative electrode layer 20.

[0131] [Effects, etc.] As disclosed in Non-Patent Document 1, various structures have been investigated for conventional solid-state batteries having a reference electrode, but the structures are complex and not easy to form.

[0132] Furthermore, the solid-state battery having a reference electrode disclosed in Patent Document 1 has a structure in which a positive electrode, a solid electrolyte layer, and a negative electrode are stacked, and a third electrode is provided as a reference electrode in contact with the solid electrolyte layer or a solid electrolyte part provided so as to connect with the positive electrode, the solid electrolyte layer, and the negative electrode, with a width that matches the length of the side surfaces thereof, and it is possible to measure the potential of the positive electrode and / or the negative electrode.

[0133] However, in the structure shown in Patent Document 1, the widths of the solid electrolyte layer and the reference electrode in the reference electrode portion are also the same, and when the reference electrode portion is pressed against the solid-state battery to perform stable potential measurement, the reference electrode may protrude from the solid electrolyte layer and come into contact with the solid-state battery, resulting in a short circuit.

[0134] In the present embodiment, in a plan view of the second main surface 130b, the area of ​​the reference electrode 110 is smaller than the area of ​​the second main surface 130b, and the reference electrode 110 is located inside the outer edge of the second main surface 130b. This makes it less likely that the reference electrode 110 will come into contact with the solid battery unit 100, compared to when the area of ​​the reference electrode 110 is equal to or larger than the area of ​​the second main surface 130b. Furthermore, even when pressure is applied to improve contact between the second solid electrolyte layer 130 and the side surface 100a of the solid battery unit 100, the reference electrode 110 will be less likely to come into contact with the solid battery unit 100, making it less likely that a short circuit will occur.

[0135] Furthermore, in this embodiment, in order to perform three-electrode measurement, the second solid electrolyte layer 130 in contact with the power generating element section 50 does not need to have a structure in which the length of the first main surface 130a precisely matches the length of the side surface of the power generating element section 50 in the stacking direction in the solid battery section 100, but only needs to have a structure that can make electrochemical contact with the power generating element section 50.

[0136] 1, the battery 500 includes a solid-state battery section 100 in which a plurality of power generating element sections 50 are electrically connected in parallel and stacked, and a structure 200 including a reference electrode 110 and a second solid electrolyte layer 130, and is configured so that the first main surface 130a and the power generating element section 50 can be brought into contact with each other by pressing the structure 200 against the side surface 100a of the solid-state battery section 100. Therefore, the electrical characteristics of the positive electrode layer 10 and / or the negative electrode layer 20 can be easily measured.

[0137] 1, the first main surface 130a of the second solid electrolyte layer 130 may be in contact with two or more of the multiple power generating element units 50 on the side surface 100a of the solid battery unit 100. This allows the first main surface 130a to be large, so that the power generating element unit 50 and the second solid electrolyte layer 130 can be in contact with each other on the side surface 100a without precise alignment. This facilitates the formation of the battery 500. Furthermore, the increased contact area between the first main surface 130a and the side surface 100a makes it difficult for the second solid electrolyte layer 130 to peel off from the solid battery unit 100, thereby improving the durability of the battery 500. Furthermore, during fabrication of the structure 200, the length of the first main surface 130a in the stacking direction can be made longer than the length of the two or more stacked power generating element units 50, so that the first main surface 130a can be easily brought into contact with the power generating element unit 50.

[0138] Furthermore, in the structure 200, the second solid electrolyte layer 130 and the reference electrode 110 are covered with the exterior body 190, which increases the mechanical strength and improves the reliability of the battery 500. Furthermore, even when the battery 500 is housed in a thin exterior body such as a laminate film, the shapes of the second solid electrolyte layer 130 and the reference electrode 110 in the structure 200 are maintained, making it possible to stably measure the potential.

[0139] For these reasons, the battery 500 can suppress short-circuiting between the reference electrode 110 and the solid-state battery section 100. Furthermore, it is possible to manufacture a battery 500 that allows measurement of electrical characteristics such as the potential of the positive electrode layer 10 and / or the negative electrode layer 20 of at least one of the plurality of stacked power generating element sections 50. Therefore, according to this embodiment, it is possible to realize a highly reliable battery 500 that allows measurement of the electrical characteristics of the electrodes.

[0140] Since the potential of the positive electrode layer 10 and / or the negative electrode layer 20 alone can be measured using the battery 500 according to this embodiment, the electrical characteristics of the positive electrode layer 10 and / or the negative electrode layer 20 can be grasped in the development of the battery, and the electrical characteristics of the positive electrode layer 10 and the negative electrode layer 20 can be measured separately, so that the development and design of the battery can be promoted effectively and efficiently.

[0141] Furthermore, when the battery 500 according to the present embodiment is applied to a practical battery, for example, the following effects can be achieved. In the positive electrode layer 10, for example, when the structure of the active material changes above a certain potential, resulting in a decrease in electrode performance, such as charge / discharge capacity and cycle characteristics, the potential of the positive electrode layer 10 can be monitored and controlled so as not to exceed that potential. As a result, in the battery 500, a decrease in electrode performance due to charging can be suppressed. In addition, in the negative electrode layer 20, for example, in the case of an electrode used up to a potential close to the metallic lithium deposition potential during charging, the deposition of metallic lithium can be suppressed by monitoring and controlling the potential so as not to reach the metallic lithium deposition potential (e.g., 0 V or less, vs. Li / Li). As a result, in the battery 500, the reduction in charge / discharge capacity and cycle deterioration that result in a shortened battery life, as well as the risk of short-circuiting, overheating, and fire that result from the deposition of metallic lithium, can be reduced.

[0142] [Variation 1] Next, a first modification of the embodiment will be described. In the following description of the modification, differences from the embodiment will be mainly described, and descriptions of commonalities will be omitted or simplified.

[0143] FIG. 4 is a cross-sectional view showing a schematic configuration of a battery 501 according to this modification.

[0144] As shown in FIG. 4, battery 501 differs from battery 500 according to the embodiment in that it includes structure 201 instead of structure 200.

[0145] The structure 201 includes a second solid electrolyte layer 130, a reference electrode 110, a reference electrode current collector 170, and an exterior body 191. The structure 201 has the same configuration as the structure 200, except that the width of the solid battery section 100 in the stacking direction is smaller than that of the structure 200.

[0146] In a plan view of the side surface 100a of the solid-state battery unit 100, the structure 201 does not extend beyond both ends of the solid-state battery unit 100 in the stacking direction of the solid-state battery unit 100. Furthermore, the length of the structure 201 in the stacking direction of the solid-state battery unit 100 is shorter than the length of the solid-state battery unit 100 in the stacking direction of the solid-state battery unit 100. In other words, in a plan view of the side surface 100a of the solid-state battery unit 100, the structure 201 is entirely located inside both ends of the solid-state battery unit 100 in the stacking direction. In this modification, in a plan view of the side surface 100a, the outermost periphery of the structure 201 is formed by the exterior body 191, and the entire exterior body 191 is entirely located inside both ends of the solid-state battery unit 100 in the stacking direction. As a result, even when the solid-state battery unit 100 is used while being pressurized in the stacking direction, the structure 201 is less likely to interfere with the pressure applied to the solid-state battery unit 100, thereby improving the reliability of the battery 501. Furthermore, even if the solid-state battery unit 100 is compressed in the stacking direction when pressure is applied to the solid-state battery unit 100 from the stacking direction, the structure 201 is located inside the solid-state battery unit 100, so it is less likely to hinder the compression of the solid-state battery unit 100, and the battery characteristics of the solid-state battery unit 100 can be improved.

[0147] [Variation 2] Next, a second modification of the embodiment will be described. In the following description of the modification, differences from the embodiment will be mainly described, and descriptions of commonalities will be omitted or simplified.

[0148] FIG. 5 is a cross-sectional view showing a schematic configuration of a battery 502 according to this modification.

[0149] As shown in FIG. 5, the battery 502 differs from the battery 500 according to the embodiment in that it includes a structure 202 instead of the structure 200 .

[0150] The structure 202 includes a second solid electrolyte layer 130 , a reference electrode 110 , a reference electrode current collector 170 , and an exterior body 192 .

[0151] The exterior body 192 has a surface 192a that faces the side surface 100a of the solid state battery unit 100. The second solid electrolyte layer 130 protrudes from the surface 192a, and the first main surface 130a at a position protruding from the surface 192a is in contact with the side surface 100a. The side surface 100a and the surface 192a are not in contact with each other, and the exterior body 192 and the solid state battery unit 100 are spaced apart.

[0152] In this way, because the second solid electrolyte layer 130 protrudes from the surface 192a, the exterior body 192 is less likely to obstruct contact between the first main surface 130a and the side surface 100a, improving the contact between the first main surface 130a and the side surface 100a. For example, even if the side surface 100a has minute irregularities, the force pressing the structure 200 against the side surface 100a is more likely to act between the first main surface 130a and the side surface 100a, making it easier to form electrochemical contact between the power generating element section 50 and the second solid electrolyte layer 130. This improves the accuracy of measuring electrical characteristics using the reference electrode 110.

[0153] [Variation 3] Next, a third modification of the embodiment will be described. In the following description of the third modification, differences from the embodiment will be mainly described, and descriptions of commonalities will be omitted or simplified.

[0154] FIG. 6 is a cross-sectional view showing a schematic configuration of a battery 503 according to this modification.

[0155] As shown in FIG. 6, battery 503 differs from battery 500 according to the embodiment in that it includes structure 203 instead of structure 200 .

[0156] The structure 203 includes a second solid electrolyte layer 130 , a reference electrode 110 , a reference electrode current collector 170 , and an exterior body 193 .

[0157] The exterior body 193 includes a first resin layer 193b and a second resin layer 193c.

[0158] The first resin layer 193b faces the solid battery section 100 with the second resin layer 193c sandwiched therebetween. The first resin layer 193b covers the portion of the second solid electrolyte layer 130 that is not covered by the second resin layer 193c, the reference electrode 110, and the reference electrode current collector 170. The first resin layer 193b includes a first insulating resin. The first resin layer 193b is made of, for example, an insulating material containing the first insulating resin as a main component. As the first insulating resin, for example, the insulating resins listed as examples of the insulating resins used for the exterior body 190 are used.

[0159] The second resin layer 193c is located between the first resin layer 193b and the solid battery unit 100. The second resin layer 193c is in contact with the side surface 100a of the solid battery unit 100. The second resin layer 193c covers the side surface of the second solid electrolyte layer 130 and is in contact with this side surface. The second resin layer 193c continuously covers the side surface 100a of the solid battery unit 100 and the side surface of the second solid electrolyte layer 130, and therefore can effectively protect the second solid electrolyte layer 130.

[0160] The second resin layer 193c is softer than the first resin layer 193b. For example, the elastic modulus of the second resin layer 193c is lower than the elastic modulus of the first resin layer 193b. As a result, the second resin layer 193c, which is softer and more easily deformed than the first resin layer 193b, comes into contact with the side surface 100a of the solid-state battery section 100. This makes it less likely that the exterior body 193 will obstruct contact between the first main surface 130a and the side surface 100a, thereby improving contact between the first main surface 130a and the side surface 100a.

[0161] Furthermore, the second resin layer 193c may be softer than the second solid electrolyte layer 130. For example, the elastic modulus of the second resin layer 193c may be lower than the elastic modulus of the second solid electrolyte layer 130. As a result, even if the side surface 100a has fine irregularities, for example, the second resin layer 193c is more easily deformed than the second solid electrolyte layer 130. Therefore, the force pressing the structure 200 against the side surface 100a is more likely to act between the first main surface 130a and the side surface 100a, and electrochemical contact is easily formed between the solid battery section 100 and the second solid electrolyte layer 130.

[0162] The second resin layer 193c includes a second insulating resin. The second resin layer 193c is made of, for example, an insulating material containing the second insulating resin as a main component. As the second insulating resin, for example, a resin having a lower elastic modulus than the first insulating resin is used. As the second insulating resin, for example, a rubber-based or elastomer-based insulating resin is used. Furthermore, as the second insulating resin, the insulating resins listed as the insulating resins used for the exterior body 190 may be used.

[0163] The second resin layer 193c may be made of a porous material containing a second insulating resin as a main component. In this case, the second insulating resin may be the same resin as the first insulating resin or may have a higher elastic modulus than the first insulating resin.

[0164] [Variation 4] Next, a fourth modification of the embodiment will be described. In the following description of the fourth modification, differences from the embodiment will be mainly described, and descriptions of commonalities will be omitted or simplified.

[0165] FIG. 7 is a cross-sectional view showing a schematic configuration of a battery 504 according to this modification.

[0166] As shown in FIG. 7, the battery 504 differs from the battery 500 according to the embodiment in that it includes a structure 204 instead of the structure 200 .

[0167] The structure 204 includes a second solid electrolyte layer 130 , a reference electrode 110 , a reference electrode current collector 170 , and an exterior body 194 .

[0168] The exterior body 194 covers the second solid electrolyte layer 130, the reference electrode 110, and the reference electrode current collector 170. The exterior body 194 covers the reference electrode current collector 170 from the side of the reference electrode 110 opposite to the solid battery unit 100 side. Therefore, the exterior body 194 covers the side of the second solid electrolyte layer 130, the side of the reference electrode 110, the side of the reference electrode current collector 170, and the main surface of the reference electrode current collector 170 opposite to the solid battery unit 100 side. The exterior body 194 and the solid battery unit 100 are arranged to sandwich the second solid electrolyte layer 130, the reference electrode 110, and the reference electrode current collector 170. The second solid electrolyte layer 130, the reference electrode 110, and the reference electrode current collector 170 are entirely enclosed by the exterior body 194 and the solid battery unit 100. In this way, the second solid electrolyte layer 130, the reference electrode 110, and the reference electrode current collector 170 are covered by the exterior body 194 that contacts the side surface 100a of the solid battery section 100, so that the contact between the second solid electrolyte layer 130 and the power generating element section 50 is maintained firmly, and the electrical characteristics of each layer can be measured stably. In particular, when the exterior body 194 contains an insulating resin, a bonding anchor effect can be exerted at the location where the insulating resin contacts the side surface 100a, so that the contact between the second solid electrolyte layer 130 and the power generating element section 50 is maintained more firmly.

[0169] Although not shown, in the battery 504, for example, a lead wire or the like that penetrates the outer casing 194 is connected to the reference electrode current collector 170, thereby forming an electrical connection between the reference electrode 110 and the outside.

[0170] (Other embodiments) While the battery according to the present disclosure has been described above based on the embodiments and modifications, the present disclosure is not limited to these embodiments and modifications. As long as they do not deviate from the gist of the present disclosure, various modifications that would occur to a person skilled in the art to the embodiments and modifications, and other forms constructed by combining some of the components of the embodiments and modifications, are also included in the scope of the present disclosure.

[0171] For example, in the above embodiment, the solid-state battery unit 100 has a structure in which a plurality of power generating element units 50 are stacked, but this is not limiting. The solid-state battery unit 100 may have a configuration including one power generating element unit 50.

[0172] Furthermore, for example, in the above embodiment, the multiple power generating element units 50 are electrically connected in parallel and stacked, but this is not limited thereto. The multiple power generating element units 50 may also be electrically connected in series and stacked. That is, the multiple power generating element units 50 may be stacked so that the opposite polarities of adjacent power generating element units 50 are electrically connected. In this case, to avoid ion conductive short circuits, the first main surface 130a of the second solid electrolyte layer 130 contacts only one of the multiple power generating element units 50. The multiple power generating element units 50 may also be connected in a combination of series and parallel connections.

[0173] Furthermore, the features of the structures in the above-described modified examples may be combined. For example, structure 201 may have a structure in which second solid electrolyte layer 130 protrudes as in structure 202, or may have a configuration including first resin layer 193b and second resin layer 193c as in structure 203, or may have reference electrode current collector 170 covered with an exterior body from the side opposite to the solid battery unit 100 side of reference electrode 110 as in structure 204. The same applies to structures 202 to 204.

[0174] Furthermore, the above-described embodiments and modifications can be subject to various changes, substitutions, additions, omissions, and the like within the scope of the claims or their equivalents. [Industrial Applicability]

[0175] The battery according to the present disclosure can be used for monitoring, designing, or developing electrodes, etc. Furthermore, the battery according to the present disclosure can be used in electronic devices, electric appliances, electric vehicles, etc. as a battery capable of measuring the electrical properties of electrodes. [Explanation of symbols]

[0176] 10 Positive electrode layer 20 negative electrode layer 30 First solid electrolyte layer 50 Power generation element 60 Positive electrode current collector 70 Negative electrode current collector 91, 92, 93 Voltage measuring instruments 100 Solid state battery section 100a side 110 Reference electrode 130 Second solid electrolyte layer 130a First principal surface 130b Second principal surface 170 Reference electrode current collector 190, 191, 192, 193, 194 Exterior body 190a, 192a side 193b First resin layer 193c Second resin layer 200, 201, 202, 203, 204 structure 500, 501, 502, 503, 504 batteries

Claims

1. a solid-state battery portion having at least one power generating element portion including a first electrode layer, a second electrode layer, and a first solid electrolyte layer located between the first electrode layer and the second electrode layer; a second solid electrolyte layer having a first main surface in contact with the at least one power generating element portion on a side surface of the solid state battery portion and a second main surface opposite to the first main surface, and a structure including a reference electrode in contact with the second main surface, the at least one power generating element unit is a plurality of power generating element units, the solid-state battery unit has a structure in which the plurality of power generating element units are stacked, the structure further includes an exterior body covering a side surface of the second solid electrolyte layer, the plurality of power generating element units are electrically connected in parallel and stacked, the first main surface is in contact with two or more of the plurality of power generating element units; battery.

2. In a plan view with respect to the second principal surface, the area of ​​the reference electrode is smaller than the area of ​​the second principal surface. The battery of claim 1 .

3. the exterior body has a surface facing a side surface of the solid-state battery unit, The second solid electrolyte layer protrudes from the surface. The battery according to claim 1 or 2.

4. the exterior body includes an insulating resin and is in contact with a side surface of the solid-state battery unit. The battery according to claim 1 or 2.

5. The outer casing is a first resin layer containing a first insulating resin; a second resin layer containing a second insulating resin and softer than the first resin layer; the second resin layer is located between the first resin layer and the solid-state battery unit and is in contact with a side surface of the solid-state battery unit; The battery of claim 4.

6. The exterior body covers a portion of the second main surface. The battery of any one of claims 1 to 5.

7. The structure further includes a reference electrode current collector in contact with the reference electrode, the outer casing covers the reference electrode and the reference electrode current collector; The battery of any one of claims 1 to 6.

8. In a plan view of a side surface of the solid-state battery unit, the structure does not extend beyond both ends of the solid-state battery unit in a stacking direction of the solid-state battery unit. The battery of any one of claims 1 to 7.

9. a length of the structure in a stacking direction of the solid-state battery unit is smaller than a length of the solid-state battery unit in the stacking direction of the solid-state battery unit; The battery of claim 8.

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