Battery

Abstract

A battery according to the present disclosure comprises a first electrode, a second electrode, a solid electrolyte layer disposed between the first electrode and the second electrode, and a moisture-absorbing material. The moisture-absorbing material is included inside of at least one selected from the group consisting of the first electrode, the second electrode, and the solid electrolyte layer. The moisture-absorbing material is in contact with a side surface of at least one selected from the group consisting of the first electrode, the second electrode, and the solid electrolyte layer.

Description

[Technical Field]

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

[0002] Patent Document 1 discloses an all-solid-state battery including a laminated exterior body, a power generating element housed in the laminated exterior body, and a water-absorbing agent disposed between the laminated exterior body and the power generating element. In this all-solid-state battery, the power generating element and the water-absorbing agent are separated by a waterproof member.

[0003] Patent Document 2 discloses a secondary battery including a battery element in which a positive electrode layer and a negative electrode layer formed on a current collector are stacked with a polymer electrolyte layer interposed therebetween, an exterior body that seals the battery element, and a sheet-like moisture absorbent material. In this secondary battery, the moisture absorbent material is disposed between the battery element and the exterior body and parallel to the current collector. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-9596 [Patent Document 2] Japanese Patent Application Laid-Open No. 2005-56672 Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present disclosure is to provide a battery with improved reliability. [Means for solving the problem]

[0006] The battery of the present disclosure comprises: A first electrode; A second electrode; a solid electrolyte layer disposed between the first electrode and the second electrode; A moisture-absorbing material; Equipped with The moisture-absorbing material is contained inside at least one selected from the group consisting of the first electrode, the second electrode, and the solid electrolyte layer, and the moisture-absorbing material is in contact with the side surface of at least one selected from the group consisting of the first electrode, the second electrode, and the solid electrolyte layer. [Effects of the Invention]

[0007] The present disclosure provides batteries with improved reliability. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a cross-sectional view and a plan view showing a schematic configuration of a battery 1000 according to a first embodiment. [Figure 2] FIG. 2 is a cross-sectional view and a plan view showing a schematic configuration of a battery 1100 according to the second embodiment. [Figure 3] FIG. 3 is a cross-sectional view and a plan view showing a schematic configuration of a battery 1200 according to the third embodiment. [Figure 4] FIG. 4 is a cross-sectional view and a plan view showing a schematic configuration of a battery 1300 according to a modification of the third embodiment. [Figure 5] FIG. 5 is a cross-sectional view and a plan view showing a schematic configuration of a battery 1400 according to the fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings.

[0010] The embodiments described below are all comprehensive or specific examples, and the numerical values, shapes, materials, components, arrangement positions and connection forms of the components shown in the following embodiments are merely examples and are not intended to limit the present disclosure.

[0011] In this specification, terms indicating the relationship between elements, such as parallelism, terms indicating the shape of elements, such as rectangle, and numerical ranges are not expressions that express only the strict meaning, but are expressions that include a substantially equivalent range, for example, a difference of about a few percent.

[0012] The drawings are schematic diagrams and are not necessarily drawn to scale. Therefore, for example, the scales of the drawings do not necessarily match. In addition, the same reference numerals are used in the drawings to designate substantially the same components, and redundant explanations are omitted or simplified.

[0013] In this specification and the drawings, the x-axis, y-axis, and z-axis represent the three axes of a three-dimensional Cartesian coordinate system. In each embodiment, the z-axis direction is the thickness direction of the battery. Furthermore, in this specification, unless otherwise specified, the "thickness direction" refers to the direction perpendicular to the plane on which each layer of the battery is stacked.

[0014] In this specification, unless otherwise specified, the term "plan view" refers to the battery viewed along the stacking direction of each layer in the battery. In this specification, unless otherwise specified, the term "thickness" refers to the length of the battery and each layer in the stacking direction.

[0015] In this specification, unless otherwise specified, in a battery and each layer constituting the battery, a "side surface" means a surface along the stacking direction of the battery and each layer, and a "main surface" means a surface other than the side surface.

[0016] In this specification, the terms "inside" and "outside" refer to the center side of the battery as "inside" and the peripheral side of the battery as "outside" when the battery is viewed along the stacking direction.

[0017] 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 with a gap between them and another component is present between them, but also when two components are arranged closely together and the two components are in contact with each other.

[0018] (First embodiment) The battery according to the first embodiment will be described below.

[0019] The battery according to the first embodiment includes a first electrode, a second electrode, a solid electrolyte layer disposed between the first electrode and the second electrode, and a moisture-absorbing material. The moisture-absorbing material is contained within at least one selected from the group consisting of the first electrode, the second electrode, and the solid electrolyte layer. Hereinafter, the inclusion of a moisture-absorbing material within a certain component may be referred to as "enclosed."

[0020] According to the above-mentioned configuration, the moisture absorbing material absorbs moisture that penetrates into the battery, thereby suppressing the diffusion of moisture inside the battery. As a result, deterioration of battery characteristics due to moisture can be reduced, and the reliability of the battery is improved.

[0021] As described in the "Background Art" section, Patent Document 1 discloses an all-solid-state battery including a laminated outer casing, a power generating element housed in the laminated outer casing, and a water-absorbing agent disposed between the laminated outer casing and the power generating element. However, the power generating element and the water-absorbing agent are separated by a waterproof member. That is, in the all-solid-state battery disclosed in Patent Document 1, the water-absorbing agent is located outside the power generating element. Therefore, the water-absorbing agent cannot absorb moisture that has penetrated into the power generating element. Furthermore, because the power generating element and the water-absorbing agent are separated by the waterproof member, there are issues with how to deal with moisture inside the power generating element. Furthermore, incorporating the water-absorbing agent and the waterproof member reduces energy density and capacity density, and further complicates the manufacturing process. As such, the all-solid-state battery disclosed in Patent Document 1 has reliability issues.

[0022] Patent Document 2 discloses a secondary battery in which a sheet-like moisture-absorbing material is disposed between a current collector and an exterior material that seals the battery element. However, the moisture-absorbing material is disposed between the current collector and the exterior material, that is, in the secondary battery disclosed in Patent Document 2, the moisture-absorbing material is located outside the battery element. Therefore, similar to Patent Document 1, the secondary battery disclosed in Patent Document 2 has an issue with how to deal with moisture that has entered the battery element.

[0023] FIG. 1 is a cross-sectional view and a plan view showing a schematic configuration of a battery 1000 according to a first embodiment.

[0024] Fig. 1(a) is a cross-sectional view of a battery 1000 according to the first embodiment. Fig. 1(b) is a plan view of the battery 1000 according to the first embodiment as seen from below in the z-axis direction. Fig. 1(a) shows a cross section taken along line II in Fig. 1(b).

[0025] 1, the battery 1000 includes a first electrode 100, a second electrode 200, a solid electrolyte layer 300 disposed between the first electrode 100 and the second electrode 200, and a moisture-absorbing material 400. The moisture-absorbing material 400 is encapsulated in at least one selected from the group consisting of the first electrode 100, the second electrode 200, and the solid electrolyte layer 300.

[0026] In FIG. 1, the moisture absorbing material 400 is encapsulated in the first electrode 100 and the solid electrolyte layer 300 .

[0027] The battery 1000 is, for example, an all-solid-state battery.

[0028] The first electrode 100 includes, for example, a first current collector 110 and a first active material layer 120.

[0029] The second electrode 200 includes, for example, a second current collector 210 and a second active material layer 220.

[0030] The first current collector 110, the first active material layer 120, the solid electrolyte layer 300, the second active material layer 220, and the second current collector 210 may all have a roughly rectangular shape in a plan view. The shape does not have to be rectangular.

[0031] In FIG. 1, the first current collector 110, the first active material layer 120, the solid electrolyte layer 300, the second active material layer 220, and the second current collector 210 are all the same size and have the same outline in a plan view, but this is not limited to this.

[0032] In a plan view, the first active material layer 120 may be smaller than the second active material layer 220.

[0033] In a plan view, the first active material layer 120 and the second active material layer 220 may be smaller than the solid electrolyte layer 300.

[0034] For example, when the solid electrolyte layer 300 covers at least one of the first active material layer 120 and the second active material layer 220, a portion of the solid electrolyte layer 300 may be in contact with at least one of the first current collector 110 and the second current collector 210.

[0035] The first electrode 100 may be a positive electrode, and the second electrode 200 may be a negative electrode. In this case, the first current collector 110 and the first active material layer 120 are a positive electrode current collector and a positive electrode active material layer, respectively. The second current collector 210 and the second active material layer 220 are a negative electrode current collector and a negative electrode active material layer, respectively.

[0036] The first electrode 100 may be a negative electrode and the second electrode 200 may be a positive electrode.

[0037] Hereinafter, the first current collector 110 and the second current collector 210 may be collectively referred to simply as "active material layers." The first active material layer 120 and the second active material layer 220 may be collectively referred to simply as "current collectors."

[0038] The current collector may be made of any conductive material, such as stainless steel, nickel (Ni), aluminum (Al), iron (Fe), titanium (Ti), copper (Cu), palladium (Pd), gold (Au), platinum (Pt), or an alloy of two or more of these metals.

[0039] The current collector may be in the form of a foil, a plate, or a mesh.

[0040] The material of the current collector can be selected taking into consideration the manufacturing process, operating temperature, operating pressure, battery operating potential applied to the current collector, or electrical conductivity. The material of the current collector can also be selected taking into consideration the tensile strength or heat resistance required for the battery. The current collector can be, for example, a high-strength electrolytic copper foil or a clad material in which foils of different metals are laminated.

[0041] The current collector may have a thickness of, for example, 10 μm or more and 100 μm or less.

[0042] The surface of the current collector may be processed into a rough surface with irregularities in order to enhance the adhesion to the active material layer (i.e., the first active material layer 120 or the second active material layer 220). Thereby, for example, the bonding property of the current collector interface is strengthened, and the mechanical and thermal reliability and cycle characteristics of the battery 1000 are improved. In addition, since the contact area between the current collector and the active material layer increases, the electrical resistance is reduced.

[0043] The first active material layer 120 may be in contact with the first current collector 110. The first active material layer 120 may cover the entire main surface of the first current collector 110.

[0044] The positive electrode active material layer contains a positive electrode active material.

[0045] The positive electrode active material is a substance in which metal ions such as lithium (Li) or magnesium (Mg) are inserted or removed into or from the crystal structure at a potential higher than that of the negative electrode, and oxidation or reduction occurs accordingly.

[0046] The positive electrode active material is, for example, a compound containing lithium and a transition metal element. The compound is, for example, an oxide containing lithium and a transition metal element, or a phosphate compound containing lithium and a transition metal element.

[0047] Examples of oxides containing lithium and a transition metal element are lithium nickel composite oxides such as LiNi x M 1-x O2 (where M is at least one selected from the group consisting of Co, Al, Mn, V, Cr, Mg, Ca, Ti, Zr, Nb, Mo, and W, and 0 < x ≦ 1 is satisfied), such as layered oxides such as cobalt lithium oxide (LiCoO2), lithium nickel oxide (LiNiO2), and lithium manganate (LiMn2O4), or lithium manganate having a spinel structure (for example, LiMn2O4, Li2MnO3, or LiMO2).

[0048] An example of a phosphate compound containing lithium and a transition metal element is lithium iron phosphate (LiFePO4) having an olivine structure.

[0049] The positive electrode active material may be sulfur (S) or a sulfide such as lithium sulfide (LiS). In this case, the positive electrode active material particles may be coated with or may have lithium niobate (LiNbO) or the like added thereto.

[0050] The positive electrode active material may be made of only one of these materials, or a combination of two or more of these materials.

[0051] To enhance lithium ion conductivity or electron conductivity, the positive electrode active material layer may contain, in addition to the positive electrode active material, a material other than the positive electrode active material. That is, the positive electrode active material layer may be a mixture layer. Examples of such materials include a solid electrolyte such as an inorganic solid electrolyte or a sulfide-based solid electrolyte, a conductive additive such as acetylene black, or a binding binder such as polyethylene oxide and polyvinylidene fluoride.

[0052] The positive electrode active material layer may have a thickness of, for example, 5 μm or more and 300 μm or less.

[0053] The moisture-absorbing material 400 may be particulate. This allows the moisture-absorbing material 400 to be dispersed within the battery 1000, thereby protecting each component of the battery 1000 from moisture present inside the battery 1000. The first electrode 100, the second electrode 200, and the solid electrolyte layer 300, which are components of the battery 1000, correspond to the components that constitute the power generation element in the all-solid-state battery of Patent Document 1. Furthermore, for example, by adding the moisture-absorbing material 400 to a slurry or paste used to fabricate the battery 1000, the moisture-absorbing material 400 can be easily incorporated into each component of the battery 1000 during the manufacturing process of the battery 1000. The moisture-absorbing material 400 may be, for example, spherical or ellipsoidal.

[0054] When the moisture-absorbing material 400 is particulate, the particle size may be, for example, 0.5 μm or more and 20 μm or less. The smaller the particle size of the moisture-absorbing material 400, the greater the surface area of ​​the moisture-absorbing material 400, allowing the moisture-absorbing material 400 to absorb moisture more effectively. The moisture-absorbing material 400 may be finely pulverized and dispersed, which can further improve the moisture absorption by the moisture-absorbing material 400.

[0055] The moisture absorbing material 400 may be contained in an amount of 0.1 volume % or more and 5.0 volume % or less in the solid electrolyte layer 300. The volume fraction of the moisture absorbing material 400 in the solid electrolyte layer 300 can be determined by observing a cross section using a scanning electron microscope (SEM) image to determine the area fraction of the moisture absorbing material 400 in the solid electrolyte layer 300, and regarding this value as the volume fraction. The cross section of the solid electrolyte layer 300 used for cross section observation is, for example, an ion-polished surface.

[0056] The moisture absorbing material 400 may be contained in an amount of 0.03 volume % or more and 0.2 volume % or less in the first electrode 100. The volume fraction of the moisture absorbing material 400 in the first electrode 100 is determined by the same method as the volume fraction of the moisture absorbing material 400 in the solid electrolyte layer 300.

[0057] The moisture-absorbing material 400 may also be contained in the second electrode 200. When the second electrode 200 contains the moisture-absorbing material 400, the moisture-absorbing material 400 may be contained in the second electrode 200 in an amount of 0.03% by volume or more and 0.2% by volume or less. The volume fraction of the moisture-absorbing material 400 in the second electrode 200 is determined by the same method as in the first electrode 100.

[0058] The moisture-absorbing material 400 may be in contact with the side surface of at least one selected from the group consisting of the first electrode 100, the second electrode 200, and the solid electrolyte layer 300. In other words, the moisture-absorbing material 400 may be contained in at least one selected from the group consisting of the first electrode 100, the second electrode 200, and the solid electrolyte layer 300, and may be in contact with the side surface from the inside. This allows moisture to be absorbed at the side surface of the battery 1000, thereby preventing moisture from entering each component of the battery 1000.

[0059] The moisture-absorbing material 400 may not only be contained within the first electrode 100, the second electrode 200, and the solid electrolyte layer 300, which are components of the battery 1000, but may also be attached to the side surfaces of these components from the outside of the components, thereby further reducing the deterioration of battery characteristics due to moisture.

[0060] The moisture absorbing material 400 may be located between particles or in void spaces of the solid electrolyte and active material.

[0061] The moisture-absorbing material 400 may cover at least a portion of the surface of the solid electrolyte particles. That is, at least one selected from the group consisting of the first electrode 100, the second electrode 200, and the solid electrolyte layer 300 may contain solid electrolyte particles, and the moisture-absorbing material 400 may cover at least a portion of the surface of the solid electrolyte particles. This makes it possible to protect the solid electrolyte particles, whose characteristics are easily deteriorated by moisture, from moisture.

[0062] Alternatively, the moisture-absorbing material 400 may cover at least a portion of the surface of the active material particles. That is, the first electrode 100 may contain active material particles, and the moisture-absorbing material 400 may cover at least a portion of the surface of the active material particles. This can protect the active material particles from moisture.

[0063] The moisture-absorbing material 400 may cover at least a portion of the surface of an aggregate of a plurality of particles. The aggregate of a plurality of particles here may be, for example, an aggregate of solid electrolyte particles, an aggregate of active material particles, or an aggregate of solid electrolyte particles and active material particles. This can protect the solid electrolyte particles and active material particles, which are susceptible to deterioration in characteristics due to moisture, from moisture.

[0064] By disposing the particulate moisture absorbing material 400 in a portion where the characteristics are likely to be deteriorated by moisture, the moisture that has entered can be selectively absorbed, thereby reducing the diffusion of moisture to other portions (e.g., materials that are weak against moisture), thereby reducing the deterioration of the characteristics of the battery 1000 due to the intrusion of moisture.

[0065] The moisture absorbing material 400 may be uniformly dispersed in at least one selected from the group consisting of the first electrode 100 , the second electrode 200 , and the solid electrolyte layer 300 .

[0066] The moisture absorbing material 400 may be contained in all of the first electrode 100, the second electrode 200, and the solid electrolyte layer 300.

[0067] The solid electrolyte layer 300 may contain the moisture absorbing material 400 at a volumetric rate higher than that of the first electrode 100 and the second electrode 200. This makes it possible to protect the solid electrolyte layer 300, whose characteristics are easily deteriorated by moisture, from moisture.

[0068] The moisture-absorbing material 400 may be any material that has moisture-absorbing properties. For example, the moisture-absorbing material 400 may be a material that can react with or adsorb moisture and that can react with or adsorb more moisture than the solid electrolyte used in the battery 1000. For example, the moisture-absorbing material 400 may be a material that has a mass change rate (i.e., moisture absorption amount) greater than that of the solid electrolyte used in the battery 1000 in an exposure time test (e.g., exposure time 0.5 to 1 hour) at room temperature (e.g., 25°C) and a constant water vapor pressure (i.e., constant humidity).

[0069] The moisture-absorbing material 400 may be a non-conductive material. Here, the term "non-conductive material" refers to a material whose electronic conductivity is 1% or less of the ionic conductivity of the solid electrolyte used in the battery 1000, for example.

[0070] The moisture absorbing material 400 may be a material that does not have ion conductivity. Here, the term "material that does not have ion conductivity" refers to a material whose ion conductivity is 1% or less of the ion conductivity of the solid electrolyte used in the battery 1000, for example.

[0071] The moisture absorbing material 400 can be an inorganic material.

[0072] The moisture-absorbing material 400 may be a material that is not oxidized or reduced by the charging and discharging of the battery 1000 .

[0073] The moisture-absorbing material 400 may contain ammonium halide. This allows the moisture-absorbing performance of the moisture-absorbing material 400 to be maintained even when the battery 1000 becomes hot during operation or manufacturing. The sublimation points of ammonium chloride and ammonium bromide are approximately 330°C and approximately 400°C, respectively. Furthermore, ammonium halide has high moisture absorption properties. Furthermore, a battery 1000 containing the moisture-absorbing material 400 can be easily manufactured by dispersing and applying a powder of the moisture-absorbing material 400 (e.g., ammonium halide powder) to a paste for manufacturing the first electrode 100, the second electrode 200, or the solid electrolyte layer 300.

[0074] A halide solid electrolyte and an ammonium halide may be used in combination. That is, at least one selected from the group consisting of the first electrode 100, the second electrode 200, and the solid electrolyte layer 300 may contain a halide solid electrolyte and an ammonium halide. Halides generally tend to have a higher thermal expansion coefficient than other compounds such as oxides. If the thermal expansion difference between adjacent materials is large, structural defects such as interfacial peeling and cracks may occur due to thermal cycling. Therefore, by using halides for both the solid electrolyte and the moisture-absorbing material 400, the above-mentioned structural defects can be suppressed. This improves the reliability of the battery 1000.

[0075] The ammonium halide may be ammonium chloride or ammonium bromide. That is, the moisture-absorbing material 400 may include at least one selected from the group consisting of ammonium chloride and ammonium bromide. This allows the battery 1000 to have excellent stability at high temperatures. For example, when ammonium chloride (NH4Cl) comes into contact with moisture, it undergoes hydrolysis (i.e., absorbs water) to produce NH4(OH) and HCl. This reaction allows ammonium chloride to act as a moisture absorbent. The same applies to ammonium bromide.

[0076] When a halide solid electrolyte and an ammonium halide are used in combination, both the halide solid electrolyte and the ammonium halide may contain at least one element selected from the group consisting of chlorine and bromine, thereby achieving a battery 1000 with high ionic conductivity and moisture absorption properties.

[0077] Two or more types of ammonium halides may be used as the moisture-absorbing material 400. For example, ammonium chloride and ammonium bromide may be used together. The temperature durability of the battery 1000 can be controlled by changing the mixing ratio of the two or more ammonium halides. For example, by increasing the proportion of ammonium bromide, high-temperature durability can be improved up to approximately 400°C. As a result, defects such as cracks occurring inside the battery 1000 due to thermal shock or thermal cycling can be suppressed. In other words, the moisture absorption performance of the moisture-absorbing material 400 can be maintained even after high-temperature thermal history, resulting in a highly reliable battery 1000.

[0078] The presence of ammonium halides in the battery can be assessed by X-ray fluorescence analysis (XRF).

[0079] The state or composition of the moisture-absorbing material 400 can be analyzed by performing composition analysis (e.g., point analysis or area analysis) on a polished cross section of the battery 1000 processed with an ion polisher or the like using an electron probe microanalyzer (EPMA) or energy dispersive X-ray analysis (EDS).

[0080] The second active material layer 220 may be in contact with the second current collector 210. The second active material layer 220 may cover the entire main surface of the second current collector 210.

[0081] The negative electrode active material layer contains a negative electrode active material.

[0082] The negative electrode active material is a material in which metal ions such as lithium (Li) ions or magnesium (Mg) ions are inserted or extracted into or from the crystalline structure at a lower potential than the positive electrode, and is therefore oxidized or reduced.

[0083] Examples of the negative electrode active material include carbon materials such as natural graphite, artificial graphite, graphite carbon fiber, and resin-baked carbon, or alloy-based materials mixed with a solid electrolyte. Examples of alloy-based materials include LiAl, LiZn, Li3Bi, Li3Cd, Li3Sb, Li4Si, and Li 4.4 Pb, Li 4.4Sn, Li 0.17 C, and lithium alloys such as LiC6, lithium titanate (Li4Ti5O 12 ), zinc oxide (ZnO), or silicon oxide (SiO x ) are metal oxides such as

[0084] The negative electrode active material may be made of only one of these materials, or may be made of a combination of two or more of these materials.

[0085] To enhance lithium ion conductivity or electron conductivity, the negative electrode active material layer may contain, in addition to the negative electrode active material, a material other than the negative electrode active material. Examples of such materials include a solid electrolyte such as an inorganic solid electrolyte or a sulfide-based solid electrolyte, a conductive additive such as acetylene black, or a binding binder such as polyethylene oxide and polyvinylidene fluoride.

[0086] The negative electrode active material layer may have a thickness of, for example, 5 μm or more and 300 μm or less.

[0087] The solid electrolyte layer 300 includes a solid electrolyte. The solid electrolyte layer 300 contains, for example, a solid electrolyte as a main component. Here, the main component refers to the component that is contained in the largest amount by mass in the solid electrolyte layer 300. The solid electrolyte layer 300 may be composed of only a solid electrolyte.

[0088] The solid electrolyte may be a known ion-conductive solid electrolyte for batteries, such as a solid electrolyte that conducts metal ions such as lithium ions or magnesium ions.

[0089] As the solid electrolyte, a sulfide solid electrolyte, an oxide solid electrolyte, or a halide solid electrolyte can be used.

[0090] Sulfide-based solid electrolytes include, for example, Li2S-P2S5-based, Li2S-SiS2-based, Li2S-B2S3-based, Li2S-GeS2-based, Li2S-SiS2-LiI-based, Li2S-SiS2-Li3PO4-based, Li2S-Ge2S2-based, Li2S-GeS2-P2S5-based, or Li2S-GeS2-ZnS-based.

[0091] Oxide-based solid electrolytes include, for example, lithium-containing metal oxides, lithium-containing metal nitrides, lithium phosphate (Li3PO4), or lithium-containing transition metal oxides. Examples of lithium-containing metal oxides are Li2O-SiO2 or Li2O-SiO2-P2O5. Examples of lithium-containing metal nitrides or lithium-containing metal oxynitrides are Li x P y O 1-z N z (0 < z ≦ 1). Examples of lithium-containing transition metal oxides are lithium titanates.

[0092] Halide-based solid electrolytes are, for example, compounds containing Li, M, and X. Here, M is at least one selected from the group consisting of metal elements and metalloid elements other than Li. X is at least one selected from the group consisting of F, Cl, Br, and I.

[0093] "Metalloid elements" are B, Si, Ge, As, Sb, and Te. "Metal elements" are all elements included in Groups 1 to 12 of the periodic table (excluding hydrogen), and all elements included in Groups 13 to 16 of the periodic table (excluding B, Si, Ge, As, Sb, Te, C, N, P, O, S, and Se).

[0094] To improve the ionic conductivity of halide-based solid electrolytes, M may contain Y. M may be Y.

[0095] Halide-based solid electrolytes include, for example, Li a Me b Y cX6, where the formula: a+mb+3c=6, and c>0 is satisfied. The value of m represents the valence of Me.

[0096] In order to improve the ionic conductivity of the halide solid electrolyte, Me may be at least one selected from the group consisting of Mg, Ca, Sr, Ba, Zn, Sc, Al, Ga, Bi, Zr, Hf, Ti, Sn, Ta, and Nb.

[0097] In order to improve the ionic conductivity of the halide solid electrolyte, X may contain at least one selected from the group consisting of Cl and Br.

[0098] The halide solid electrolyte may include, for example, at least one selected from the group consisting of Li3YCl6 and Li3YBr6.

[0099] As the solid electrolyte, only one of these materials may be used, or two or more of these materials may be used in combination.

[0100] The solid electrolyte layer 300 may contain, in addition to the solid electrolyte, a binder such as polyethylene oxide or polyvinylidene fluoride.

[0101] The solid electrolyte layer 300 may have a thickness of, for example, 5 μm or more and 150 μm or less.

[0102] The solid electrolyte material may be composed of an agglomerate of particles, or may be composed of a sintered structure.

[0103] (Second embodiment) The battery according to the second embodiment will be described below. The matters described in the first embodiment may be omitted as appropriate.

[0104] FIG. 2 is a cross-sectional view and a plan view showing a schematic configuration of a battery 1100 according to the second embodiment.

[0105] Fig. 2(a) is a cross-sectional view of a battery 1100 according to the second embodiment. Fig. 2(b) is a plan view of the battery 1100 according to the second embodiment as seen from below in the z-axis direction. Fig. 2(a) shows a cross section taken along line II-II in Fig. 2(b).

[0106] 2, in the battery 1100, the solid electrolyte layer 301 includes a first solid electrolyte layer 301a and a second solid electrolyte layer 301b. The first solid electrolyte layer 301a is disposed between the first electrode 100 and the second solid electrolyte layer 301b. The moisture absorbing material 401 is encapsulated in the solid electrolyte layer 301. The volume ratio of the moisture absorbing material 401 in the first solid electrolyte layer 301a is higher than the volume ratio of the moisture absorbing material 401 in the second solid electrolyte layer 301b.

[0107] As shown in FIG. 2, in the battery 1100, the moisture-absorbing material 401 is also contained in the first electrode 100.

[0108] The above configuration can prevent moisture from penetrating into the first electrode 100. Therefore, even if the first electrode 100 has low water resistance, a highly reliable battery can be realized.

[0109] As shown in FIG. 2, the second solid electrolyte layer 301b may not include the moisture absorbing material 401.

[0110] 2 is in particulate form, the moisture absorbing material contained in first solid electrolyte layer 301a may be in layer form. For example, the moisture absorbing material may be disposed as a layer along the interface of first solid electrolyte layer 301a on the first electrode 100 side.

[0111] In first solid electrolyte layer 301a, moisture absorbing material 401 may be arranged in greater amount on the first electrode 100 side. That is, in first solid electrolyte layer 301a, the closer to first electrode 100, the higher the concentration of moisture absorbing material 401. This can further prevent moisture from penetrating into first electrode 100.

[0112] The solid electrolyte constituting the first solid electrolyte layer 301a may be a material having a different composition from the solid electrolyte constituting the second solid electrolyte layer 301b. This allows the use of solid electrolytes suitable for the positive and negative electrode materials. For example, when the first electrode 100 is a positive electrode, from the viewpoint of electrochemical stability, the first solid electrolyte layer 301a may contain a halide solid electrolyte, and the second solid electrolyte layer 301b may contain a sulfide. Because the first solid electrolyte layer 301a contains the moisture-absorbing material 401, the solid electrolyte constituting the first solid electrolyte layer 301a may have low water resistance.

[0113] (Third embodiment) The battery according to the third embodiment will be described below. The matters described in the above embodiments may be omitted as appropriate.

[0114] FIG. 3 is a cross-sectional view and a plan view showing a schematic configuration of a battery 1200 according to the third embodiment.

[0115] Fig. 3(a) is a cross-sectional view of a battery 1200 according to the third embodiment. Fig. 3(b) is a plan view of the battery 1200 according to the third embodiment as viewed from below in the z-axis direction. Fig. 3(a) shows a cross section taken along line III-III in Fig. 3(b).

[0116] The battery 1200 differs from the battery 1000 according to the first embodiment in that it further includes a moisture absorbing layer 500 that covers at least a portion of the side surface of at least one selected from the group consisting of the first electrode 100, the second electrode 200, and the solid electrolyte layer 300. As shown in FIG. 3 , the battery 1200 may include the moisture absorbing layer 500 so as to cover the side surface of the battery 1200.

[0117] The above configuration can prevent moisture from penetrating into the components of the battery 1200 from the sidewall surface of the battery 1200. This makes it possible to realize a battery 1200 with excellent water resistance. Furthermore, the moisture absorbing layer 500 can also function as a coating layer because it can prevent foreign matter from adhering and the active material layer from falling off. As described above, the moisture absorbing layer 500 can improve the reliability of the battery 1200.

[0118] The moisture absorbing layer 500 includes a moisture absorbing material. The moisture absorbing material may be the same as or different from the moisture absorbing material 400 contained in at least one selected from the group consisting of the first electrode 100, the second electrode 200, and the solid electrolyte layer 300.

[0119] The moisture absorbing layer 500 may include an ammonium halide.

[0120] The moisture absorption layer 500 is formed, for example, by applying a paste containing particles containing ammonium halide and an organic binder for binding to at least one side surface selected from the group consisting of the first electrode 100, the second electrode 200, and the solid electrolyte layer 300, and drying the paste.

[0121] The moisture absorbing layer 500 may have a thickness of, for example, 1 μm or more and 30 μm or less.

[0122] The moisture absorbing layer 500 may be arranged so as not to cover the side surfaces of the second electrode 200 .

[0123] FIG. 4 is a cross-sectional view and a plan view showing a schematic configuration of a battery 1300 according to a modification of the third embodiment.

[0124] Fig. 4(a) is a cross-sectional view of the battery 1300. Fig. 4(b) is a plan view of the battery 1300 as seen from below in the z-axis direction. Fig. 4(a) shows a cross section taken along line IV-IV in Fig. 4(b).

[0125] 4, the battery 1300 includes a moisture absorbing layer 501 that covers the side surfaces of the first electrode 100 and the solid electrolyte layer 300 of the battery 1300. The moisture absorbing layer 501 does not cover the side surfaces of the second electrode 200.

[0126] The second electrode 200 may be a negative electrode.

[0127] According to the above configuration, for example, it is not necessary to provide a moisture absorption layer on the side surface of a layer that expands and contracts significantly due to charging and discharging (e.g., a negative electrode formed of a carbon or silicon-based material). As a result, peeling of the moisture absorption layer due to repeated expansion and contraction can be prevented. Therefore, the reliability of the battery 1300 can be improved.

[0128] (Fourth embodiment) A battery according to a fourth embodiment will be described below. The matters described in the above embodiments may be omitted as appropriate.

[0129] FIG. 5 is a cross-sectional view and a plan view showing a schematic configuration of a battery 1400 according to the fourth embodiment.

[0130] Fig. 5(a) is a cross-sectional view of a battery 1400 according to the fourth embodiment. Fig. 5(b) is a plan view of the battery 1400 according to the fourth embodiment as viewed from below in the z-axis direction. Fig. 5(a) shows a cross section taken along line VV in Fig. 5(b).

[0131] As shown in FIG. 5, in a plan view of the battery 1400, the moisture absorbing material 402 is arranged at a higher volume ratio on the outer edge side of the battery 1400 than on the center side.

[0132] According to the above configuration, it is possible to improve the moisture absorption performance near the outer edge of the battery 1400, which is likely to come into contact with moisture, and therefore the reliability of the battery 1400 can be improved.

[0133] The inner edge shape in plan view of the region with a high volume fraction of moisture absorbent material 402 is, for example, rectangular, circular, or polygonal. By forming the region with a high concentration of moisture absorbent material 402 in a shape that can protect the inside of the battery, the reliability of the battery can be improved.

[0134] The concentration of moisture absorbent material 402 may increase continuously or in steps from the center to the outer periphery of battery 1400 .

[0135] [Battery manufacturing method] The method for manufacturing the battery of the present disclosure will now be described.

[0136] Here, as an example, a method for manufacturing the battery 1000 according to the first embodiment will be described.

[0137] In the following description, the first electrode 100 is the positive electrode and the second electrode 200 is the negative electrode.

[0138] First, pastes to be used for printing the positive electrode active material layer and the negative electrode active material layer are prepared.

[0139] As the solid electrolyte used in the active material layer mixture, for example, a powder having an average particle size of about 3 μm and containing a halide solid electrolyte as a main component is prepared. This halide solid electrolyte has a particle size of, for example, 1×10 -3 S / cm to 3×10 -3 The halide solid electrolyte has an ionic conductivity of 1000 S / cm. The halide solid electrolyte is, for example, Li3YCl6 or Li3YBr6.

[0140] As the positive electrode active material, for example, a layered Li·Ni·Co·Al composite oxide (e.g., LiNi 0.8 Co 0.15 Al 0.05 O2) powder is used.

[0141] As the moisture-absorbing material, for example, ammonium chloride powder having an average particle size of about 1 μm is used.

[0142] The positive electrode active material layer paste is prepared by dispersing the above-mentioned positive electrode active material, the above-mentioned solid electrolyte powder, and the moisture absorbing material powder in an organic solvent, etc. The positive electrode active material layer paste is prepared, for example, by a triple roll mill.

[0143] As the negative electrode active material, for example, natural graphite powder having an average particle size of about 10 μm is used.

[0144] The above-mentioned negative electrode active material and the above-mentioned solid electrolyte powder are dispersed in an organic solvent or the like to prepare a paste for the negative electrode active material layer.

[0145] Next, copper foils, for example, about 30 μm thick, are prepared as the positive electrode current collector and the negative electrode current collector. A paste for the positive electrode active material layer and a paste for the negative electrode active material layer containing a moisture-absorbing material are printed on one surface of each copper foil by screen printing in a predetermined shape and with a thickness of about 50 μm to 100 μm. The paste for the positive electrode active material layer and the paste for the negative electrode active material layer are dried at 80°C to 130°C. In this way, a positive electrode active material layer is formed on the positive electrode current collector, and a negative electrode active material layer is formed on the negative electrode current collector. The positive electrode and the negative electrode each have a thickness of 30 μm to 60 μm.

[0146] Next, the solid electrolyte powder and moisture-absorbing material are dispersed in an organic solvent or the like to prepare a paste for the solid electrolyte layer. The paste for the solid electrolyte layer is printed on the positive electrode and the negative electrode using a metal mask, for example, to a thickness of about 100 μm. The positive electrode and the negative electrode on which the paste for the solid electrolyte layer of the first electrode 100 is printed are dried at 80°C to 130°C.

[0147] Next, the solid electrolyte formed on the positive electrode and the solid electrolyte formed on the negative electrode are stacked so as to be in contact with each other and face each other, and the stacked body is placed in a die mold having a rectangular outer shape.

[0148] Next, a 70 μm thick, 5×10 elastic modulus sheet was placed between the pressure die punch and the laminate. 6An elastic sheet of about 100 MPa is inserted. With this configuration, pressure is applied to the laminate via the elastic sheet. The press mold is then heated to 50°C at a pressure of 300 MPa for 90 seconds. This results in a laminate consisting of a positive electrode current collector, a positive electrode active material layer, a solid electrolyte layer, a negative electrode active material layer, and a negative electrode current collector. The positive electrode active material layer and the solid electrolyte layer contain a moisture-absorbing material.

[0149] The method and order of manufacturing the battery are not limited to the above example.

[0150] In the above-described manufacturing method, the positive electrode active material layer paste, the negative electrode active material layer paste, and the solid electrolyte layer paste are applied by printing, but the present invention is not limited to this. Examples of printing methods that can be used include doctor blade printing, calendar printing, spin coating, dip coating, inkjet printing, offset printing, die coating, and spray printing.

[0151] While the battery of the present disclosure has been described above based on the embodiments, the present disclosure is not limited to these embodiments. As long as they do not deviate from the gist of the present disclosure, various modifications conceivable by those skilled in the art to the embodiments and other forms constructed by combining some of the components of the embodiments are also included in the scope of the present disclosure. [Industrial Applicability]

[0152] The battery according to the present disclosure can be used as a secondary battery such as an all-solid-state lithium-ion battery used in various electronic devices or automobiles, for example. [Explanation of symbols]

[0153] 100 1st electrode 110 First current collector 120 First active material layer 200 2nd electrode 210 Second current collector 220 Second active material layer 300, 301 solid electrolyte layer 301a First Solid Electrolyte Layer 301b Second Solid Electrolyte Layer 400, 401, 402 hygroscopic materials 500, 501 moisture-absorbing layer 1000, 1100, 1200, 1300, 1400 batteries

Claims

1. A first electrode; A second electrode; a solid electrolyte layer disposed between the first electrode and the second electrode; A moisture-absorbing material; A battery comprising: the moisture-absorbing material is contained in at least one selected from the group consisting of the first electrode, the second electrode, and the solid electrolyte layer; the moisture-absorbing material is in contact with at least one side surface selected from the group consisting of the first electrode, the second electrode, and the solid electrolyte layer; The battery satisfies at least one configuration selected from the group consisting of the following (I) and (II): battery. (I) At least one selected from the group consisting of the first electrode, the second electrode, and the solid electrolyte layer contains solid electrolyte particles, and the moisture-absorbing material covers at least a portion of the surface of the solid electrolyte particles. (II) The first electrode contains active material particles, and the moisture-absorbing material is contained in the first electrode and covers at least a portion of the surface of the active material particles.

2. Satisfying the configuration of (I) The battery of claim 1 .

3. Satisfying the configuration of (II) The battery of claim 1 .

4. The moisture-absorbing material is in particulate form. The battery of claim 1 .

5. the moisture-absorbing material comprises an ammonium halide; The battery of claim 1 .

6. The moisture-absorbing material includes at least one selected from the group consisting of ammonium chloride and ammonium bromide. The battery of claim 5.

7. at least one selected from the group consisting of the first electrode, the second electrode, and the solid electrolyte layer contains a halide solid electrolyte; The battery of claim 5.

8. The halide solid electrolyte contains at least one element selected from the group consisting of chlorine and bromine. The battery of claim 7.

9. the solid electrolyte layer contains the moisture-absorbing material at a volume fraction higher than that of the first electrode and the second electrode; The battery of claim 1 .

10. In a plan view of the battery, the moisture-absorbing material is disposed at a higher volume ratio on the outer edge side than on the center side of the battery. The battery of claim 1 .

11. the solid electrolyte layer includes a first solid electrolyte layer and a second solid electrolyte layer, the first solid electrolyte layer is disposed between the first electrode and the second solid electrolyte layer; a volume ratio of the moisture absorbing material in the first solid electrolyte layer is higher than a volume ratio of the moisture absorbing material in the second solid electrolyte layer; The battery of claim 1 .

12. the second solid electrolyte layer does not contain the moisture absorbing material; The battery of claim 11.

13. Further provided with a moisture absorbing layer, the moisture absorbing layer covers at least a portion of a side surface of at least one selected from the group consisting of the first electrode, the second electrode, and the solid electrolyte layer; The battery of claim 1 .

14. the moisture absorbing layer does not cover the side surface of the second electrode; 14. The battery of claim 13.

15. The second electrode is a negative electrode.

15. The battery of claim 14.

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