All-solid-state battery and battery module

Abstract

An all-solid-state battery (10) satisfies at least one of the following requirements 1 and 2 and includes, in order: a positive electrode including a positive electrode active material layer (1); a solid electrolyte layer (5) including a solid electrolyte (A); and a negative electrode including a negative electrode active material layer (2). Requirement 1: the positive electrode active material layer (1) and the solid electrolyte layer (5) are in contact with each other, and when the contact length at the interface between the positive electrode active material layer (1) and the solid electrolyte layer (5) is L1A and the linear length is L2A, a ratio of L1A to L2A (L1A / L2A) is from 1.1 to 1.4. Requirement 2: the negative electrode active material layer (2) and the solid electrolyte layer (5) are in contact with each other, and when the contact length at the interface between the negative electrode active material layer (2) and the solid electrolyte layer (5) is L1B and the linear length is L2B, a ratio of L1B to L2B (L1B / L2B) is from 1.05 to 2.50.

Description

All-solid-state battery and battery module

[0001] The present invention relates to an all-solid-state battery and a battery module.

[0002] The all-solid-state battery includes, for example, a positive electrode active material layer, a solid electrolyte layer, and a negative electrode active material layer in this order. Patent Document 1 describes a technique relating to the all-solid-state battery.

[0003] Patent Document 1 aims to provide, through the development of a manufacturing technology for all-solid-state secondary batteries, an all-solid-state secondary battery that exhibits good ion conductivity and effectively improves resistance to peeling between the active material layer and the inorganic solid electrolyte layer. The all-solid-state secondary battery has a positive electrode active material layer, a negative electrode active material layer, and an inorganic solid electrolyte layer interposed between the two layers, wherein the inorganic solid electrolyte layer contains an ion-conductive inorganic solid electrolyte, and the maximum height roughness Rz of at least one of the interfaces between the positive electrode active material layer and the inorganic solid electrolyte layer or the interface between the negative electrode active material layer and the inorganic solid electrolyte layer is 1.5 μm to 5 μm.

[0004] JP 2015-195183 A

[0005] One aspect of the present invention is to provide an all-solid-state battery having improved cycle characteristics and improved high-rate discharge characteristics.

[0006] According to the present invention, the following all-solid-state battery and battery module are provided.

[0007] [1] An all-solid-state battery comprising, in this order: a positive electrode including a positive electrode active material layer; a solid electrolyte layer including a solid electrolyte (A); and a negative electrode including a negative electrode active material layer, and satisfying at least one of the following requirements 1 and 2. Requirement 1: The positive electrode active material layer and the solid electrolyte layer are in contact with each other, and the contact length of the interface between the positive electrode active material layer and the solid electrolyte layer measured by the following method 1 is L １Ａ The straight line length is L ２Ａ When this is done, L １Ａ and L ２Ａ The ratio (L １Ａ / L ２Ａ) is 1.1 or more and 1.4 or less (Method 1) A cross section of the cathode active material layer and the solid electrolyte layer is photographed using a scanning electron microscope (SEM) at a magnification of 2000 times, with the direction in which the cathode active material layer and the solid electrolyte layer are stacked being the vertical direction, so that the interface between the cathode active material layer and the solid electrolyte layer includes 60 μm or more in the horizontal direction. From the obtained cross-sectional SEM image, the linear length L of the interface between the cathode active material layer and the solid electrolyte layer is calculated using image analysis software. ２Ａ and contact length L １Ａ Measure the contact length L １Ａ is the length of the contact surface obtained by sampling the contact points between the positive electrode active material and the solid electrolyte in a 60 μm section in the horizontal direction in a cross-sectional SEM image and connecting each contact point with a straight line, and the straight line length L ２Ａ is the contact length L １Ａ Requirement 2: The negative electrode active material layer and the solid electrolyte layer are in contact with each other, and the contact length of the interface between the negative electrode active material layer and the solid electrolyte layer measured by the following method 2 is defined as L １Ｂ The straight line length is L ２Ｂ When this is done, L １Ｂ and L ２Ｂ The ratio (L １Ｂ / L ２Ｂ ) is 1.05 or more and 2.50 or less. (Method 2) A cross section of the negative electrode active material layer and the solid electrolyte layer is photographed using a scanning electron microscope (SEM) at a magnification of 2000 times, with the direction in which the negative electrode active material layer and the solid electrolyte layer are stacked being the vertical direction, so that the interface between the negative electrode active material layer and the solid electrolyte layer includes 60 μm or more in the horizontal direction. From the obtained cross-sectional SEM image, the linear length L of the interface between the negative electrode active material layer and the solid electrolyte layer is calculated using image analysis software. ２Ｂ and contact length L １Ｂ Measure the contact length L １Ｂis the length of the contact surface obtained by sampling contact points between the negative electrode active material and the solid electrolyte in a 60 μm section in the horizontal direction in a cross-sectional SEM image and connecting each contact point with a straight line, and the straight line length L ２Ｂ is the contact length L １Ｂ The length of the line is defined as the length of the line obtained by connecting two of the contact points sampled when measuring the contact resistance and projecting the line onto a horizontal plane. [2] The all-solid-state battery according to [1], which satisfies the requirement 1. [3] The all-solid-state battery according to [2], wherein the positive electrode active material layer contains, as a positive electrode active material, a lithium composite oxide having a layered rock-salt crystal structure. [4] The all-solid-state battery according to [3], wherein the lithium composite oxide contains one or more selected from the group consisting of lithium-nickel composite oxide, lithium-cobalt composite oxide, lithium-nickel-aluminum composite oxide, and lithium-nickel-cobalt-manganese composite oxide. [5] The all-solid-state battery according to [4], wherein the lithium composite oxide contains lithium-nickel-cobalt-manganese composite oxide. [6] The all-solid-state battery according to any one of claims [2] to [5], wherein the negative electrode active material layer contains one or more negative electrode active materials selected from the group consisting of a carbon material, a lithium-based metal material, a Si-based material, and a conductive polymer material. [7] The all-solid-state battery according to [1], which satisfies the requirement 2. [8] The all-solid-state battery according to [7], wherein the negative electrode active material layer includes a lithium layer on a surface in contact with the solid electrolyte layer. [9] The all-solid-state battery according to [7], wherein the negative electrode active material layer includes a layer formed of an alloy containing lithium and magnesium on a surface in contact with the solid electrolyte layer.

[10] L １Ｂ and L ２Ｂ The ratio (L １Ｂ / L ２Ｂ) is 1.20 or more and 2.50 or less.

[11] The all-solid-state battery according to any of [1] to

[10] , wherein the solid electrolyte (A) contains one or more selected from the group consisting of a sulfide-based solid electrolyte, an oxide-based solid electrolyte, and a polymer-based solid electrolyte.

[12] The all-solid-state battery according to any of [1] to

[11] , wherein the content of the solid electrolyte (A) in the solid electrolyte layer is 50.0 parts by mass or more and 100.0 parts by mass or less, when the entire solid electrolyte layer is taken as 100.0 parts by mass.

[13] A battery module comprising the all-solid-state battery according to any of [1] to

[12] .

[0008] According to one aspect of the present invention, an all-solid-state battery having improved cycle characteristics and high-rate discharge characteristics can be provided.

[0009] 1 is a cross-sectional view showing an example of the structure of an all-solid-state battery according to the present embodiment. １Ａ and the straight line length L ２Ａ 10 is a top view of the interface α for explaining the measurement position of the contact length L at the interface α between the solid electrolyte layer and the negative electrode active material layer in the second embodiment. １Ｂ and the straight line length L ２Ｂ FIG. 10 is a top view of the interface α for explaining the measurement site.

[0010] Each embodiment of the present invention will be described below. Note that the shapes, sizes, and layouts of the components in the drawings are shown only to the extent that the present invention can be understood, and are not to scale. Furthermore, unless otherwise specified, "to" in a numerical range indicates a range from above to below.

[0011] The all-solid-state battery of this embodiment includes, in this order, a positive electrode including a positive electrode active material layer 1, a solid electrolyte layer 5 including a solid electrolyte (A), and a negative electrode including a negative electrode active material layer 2, and satisfies at least one of the following requirements 1 and 2. Requirement 1: The positive electrode active material layer 1 and the solid electrolyte layer 5 are in contact with each other, and the contact length of the interface between the positive electrode active material layer 1 and the solid electrolyte layer 5, measured by the following method 1, is L １Ａ The straight line length is L２Ａ When this is done, L １Ａ and L ２Ａ The ratio (L １Ａ / L ２Ａ ) is 1.1 or more and 1.4 or less (Method 1) A cross section of the positive electrode active material layer 1 and the solid electrolyte layer 5 is photographed using a scanning electron microscope (SEM) at a magnification of 2000 times, with the direction in which the positive electrode active material layer 1 and the solid electrolyte layer 5 are stacked being the vertical direction, so that the interface between the positive electrode active material layer 1 and the solid electrolyte layer 5 includes 60 μm or more in the horizontal direction. From the obtained cross-sectional SEM image, the linear length L of the interface between the positive electrode active material layer 1 and the solid electrolyte layer 5 is calculated using image analysis software. ２Ａ and contact length L １Ａ Measure the contact length L １Ａ is the length of the contact surface obtained by sampling the contact points between the positive electrode active material and the solid electrolyte in a 60 μm section in the horizontal direction in a cross-sectional SEM image and connecting each contact point with a straight line, and the straight line length L ２Ａ is the contact length L １Ａ Requirement 2: The negative electrode active material layer 2 and the solid electrolyte layer 5 are in contact with each other, and the contact length of the interface between the negative electrode active material layer 2 and the solid electrolyte layer 5 measured by the following method 2 is defined as L １Ｂ The straight line length is L ２Ｂ When this is done, L １Ｂ and L ２Ｂ The ratio (L １Ｂ / L ２Ｂ ) is 1.05 or more and 2.50 or less. (Method 2) With the direction in which the negative electrode active material layer 2 and the solid electrolyte layer 5 are stacked as the vertical direction, a cross section of the negative electrode active material layer 2 and the solid electrolyte layer 5 is photographed using a scanning electron microscope (SEM) at a magnification of 2000 times so that the interface between the negative electrode active material layer 2 and the solid electrolyte layer 5 includes 60 μm or more in the horizontal direction. From the obtained cross-sectional SEM image, the linear length L of the interface between the negative electrode active material layer 2 and the solid electrolyte layer 5 is calculated using image analysis software. ２Ｂ and contact length L １Ｂ Measure the contact length L １Ｂis the length of the contact surface obtained by sampling contact points between the negative electrode active material and the solid electrolyte in a 60 μm section in the horizontal direction in a cross-sectional SEM image and connecting each contact point with a straight line, and the straight line length L ２Ｂ is the contact length L １Ｂ When measuring the contact point, the two ends of the sampled contact points are connected by a straight line, and the length of the line obtained by projecting the line onto a horizontal plane is the length of the line.

[0012] First Embodiment Hereinafter, an all-solid-state battery and an all-solid-state battery module according to a first embodiment of the present invention will be described.

[0013] 1 is a cross-sectional view showing an example of the structure of an all-solid-state battery 10 of the first embodiment. The all-solid-state battery 10 of the first embodiment includes, in this order, a positive electrode including a positive electrode active material layer 1, a solid electrolyte layer 5 including a solid electrolyte (A), and a negative electrode including a negative electrode active material layer 2, the positive electrode active material layer 1 and the solid electrolyte layer 5 are in contact with each other, and the contact length of the interface between the positive electrode active material layer 1 and the solid electrolyte layer 5 measured by the following method 1 is defined as L １Ａ The straight line length is L ２Ａ When this is done, L １Ａ and L ２Ａ The ratio (L １Ａ / L ２Ａ ) is 1.1 or more and 1.4 or less. １Ａ / L ２Ａ From the viewpoint of further improving the cycle characteristics of the all-solid-state battery, the (L １Ａ / L ２Ａ ) can be adjusted by adjusting, for example, the conditions for compressing the electrode laminate precursor in the process of producing the all-solid-state battery, the type and blending ratio of the positive electrode active material in the positive electrode active material layer, the type and blending ratio of the solid electrolyte in the solid electrolyte layer, etc., and in particular, １Ａ / L ２Ａ In order to set the thickness (μm) of the electrode laminate precursor to within the above range, the conditions for compressing the electrode laminate precursor in the process of producing an all-solid-state battery are important.

[0014] In the first embodiment, the contact length L in the cross section of the interface between the positive electrode active material layer and the solid electrolyte layer１Ａ and the straight line length L ２Ａ can be measured from the cross-sectional SEM image obtained using a scanning electron microscope (SEM) by the following method 1, and using image analysis software. (Method 1) The direction in which the positive electrode active material layer and the solid electrolyte layer are stacked is set as the vertical direction, and a cross section of the positive electrode active material layer and the solid electrolyte layer is photographed using a scanning electron microscope (SEM) at a magnification of 2000 times so that the interface between the positive electrode active material layer and the solid electrolyte layer includes 60 μm or more in the horizontal direction. From the obtained cross-sectional SEM image, the linear length L of the interface between the positive electrode active material layer and the solid electrolyte layer is calculated using image analysis software (for example, Image J (National Institutes of Health)). ２Ａ and contact length L １Ａ Measure the contact length L １Ａ is the length of the contact surface obtained by sampling the contact points between the positive electrode active material and the solid electrolyte in a 60 μm section in the horizontal direction in the cross-sectional SEM image and connecting each contact point with a straight line, and the straight line length L ２Ａ is the contact length L １Ａ When measuring the contact point, the two ends of the sampled contact points are connected by a straight line, and the length of the line obtained by projecting the line onto a horizontal plane is the length of the line.

[0015] As a result of the investigations by the present inventors, it was found that the contact length L １Ａ and the straight line length L ２Ａ The ratio (L １Ａ / L ２Ａ Based on the above findings, the present inventors have further conducted extensive research and found that there is a relationship between the L １Ａ / L ２Ａ The inventors have found that by setting L within the above range, the cycle characteristics of the all-solid-state battery can be improved, and have completed the present invention. １Ａ / L ２Ａ The reason why the cycle characteristics of the all-solid-state battery can be improved when L is within the above range is not clear, but １Ａ / L ２ＡIt is presumed that the contact area between the positive electrode active material and the solid electrolyte falls within an appropriate range when the thickness is within the above range, thereby improving the cycle characteristics of the all-solid-state battery.

[0016] Here, the contact length L of the interface between the solid electrolyte layer and the positive electrode active material layer in the all-solid-state battery of the first embodiment １Ａ and the straight line length L ２Ａ The contact length L １Ａ The term "linear length L" refers to the length of the contact surface obtained by horizontally sampling contact points between the positive electrode active material and the solid electrolyte at the interface between the solid electrolyte layer and the positive electrode active material layer in a cross-sectional SEM image taken using a scanning electron microscope (SEM) and connecting each contact point with a straight line, and means the actual length of the interface between the positive electrode active material layer 1 and the solid electrolyte layer 5. ２ is the contact length L of the interface between the positive electrode active material layer 1 and the solid electrolyte layer 5. １Ａ The length of the projected line when projected onto a horizontal plane.

[0017] Here, referring to FIG. 2, the contact length L at the interface α between the positive electrode active material layer and the solid electrolyte layer is １Ａ and the straight line length L ２Ａ The ratio (L １Ａ / L ２Ａ 2 shows the measurement site of the contact length L at the interface α between the solid electrolyte layer and the positive electrode active material layer in the first embodiment. １Ａ and the straight line length L ２Ａ 1 is a top view of the interface α for explaining the measurement position of the positive electrode active material layer 1 and the solid electrolyte layer 5. １ Select center line b １ A line b is parallel to ２ and b ３ Select center line b １ Center line b perpendicular to ４ Select center line b ４ A line b is parallel to ５ and b ６ The vertical distance between each line is d １ ~d ４ is, for example, 5 mm or more and 20 mm or less.１ and center line b ４ Area a centered on the intersection of １ Select center line b １ and line b ５ Area a centered on the intersection of ２ Select center line b １ and line b ６ Area a centered on the intersection of ３ Select the line b ２ and center line b ４ Area a centered on the intersection of ４ Select the line b ２ and line b ５ Area a centered on the intersection of ５ Select the line b ２ and line b ６ Area a centered on the intersection of ６ Select the line b ３ and center line b ４ Area a centered on the intersection of ７ Select the line b ３ and line b ５ Area a centered on the intersection of ８ Select the line b ３ and line b ６ Area a centered on the intersection of ９ Then, select the area a １ ~a ９ A cross section was prepared, and a cross section SEM image was taken using a scanning electron microscope (SEM). １ ~a ９ Contact length L １Ａ Then, in the region a １ ~a ９ The straight line length L ２Ａ For example, in the area a １ ~a ９ The straight line length L ２Ａ is the area a １ ~a ９ Then, the area a １ ~a ９ The straight line length L ２Ａ The area a for the average value of １ ~a ９Contact length L １Ａ The ratio of the average value of (area a １ ~a ９ Contact length L １Ａ Average value / area a １ ~a ９ The straight line length L ２Ａ This is used as the contact length L at the interface α between the positive electrode active material layer 1 and the solid electrolyte layer 5. １Ａ and the straight line length L ２Ａ The ratio (L １Ａ / L ２Ａ )

[0018] As the scanning electron microscope (SEM), for example, an SU1500 manufactured by Hitachi High-Tech Corporation can be used. The magnification during measurement is, for example, 2000 times.

[0019] (Solid Electrolyte Layer) The solid electrolyte layer of the first embodiment contains a solid electrolyte (A).

[0020] The solid electrolyte (A) of the first embodiment preferably contains one or more selected from the group consisting of sulfide-based solid electrolytes, oxide-based solid electrolytes, and polymer-based solid electrolytes, from the viewpoint of further improving the cycle characteristics of the all-solid-state battery.

[0021] The sulfide-based solid electrolyte is, for example, Li ２ S-P ２ S ５ Material, Li ２ S-SiS ２ Material, Li ２ S-GeS ２ Material, Li ２ S-Al ２ S ３ Material, Li ２ S-SiS ２ -Li ３ P.O. ４ Material, Li ２ S-P ２ S ５ -GeS ２ Material, Li ２ S-Li ２ O-P ２ S ５ -SiS ２Materials, Li ２ S-GeS ２ -P ２ S ５ -SiS ２ Materials, Li ２ S-SnS ２ -P ２ S ５ -SiS ２ Materials, Li ２ S-P ２ S ５ -Li ３ N material, Li ２ S ２＋Ｘ -P ４ S ３ Materials, Li ２ S-P ２ S ５ -P ４ S ３ Materials, LiPO ４ -Li ２ S-SiS materials, Li ３ PS ４ 、Li ３ PO ４ -Li ２ S-Si ２ S material, Li ３ PO ４ -Li ２ S-SiS ２ Materials, LiI-Li ２ S-B ２ S ３ Materials, LiI-Li ２ S-SiS ２ Materials, LiI-Li ２ S-P ２ S ５ Materials, LiI-Li ２ S-P ２ O ５ Materials, LiI-Li ３ PO ４ -P ２ S ５ Li ２ S-P ２ S ５ -LiCl materials, Li ７－ｘ PS ６－ｘ Cl ｘ (ただし、0≦x≦2)、Li ７－ｘ PS ６－ｘ Br ｘ(where 0≦x≦2), Li ７－ｘ P.S. ６－ｘ I ｘ (where 0≦x≦2), Li １０ GeP ２ S １２ , and Li ３．２５ Ge ０．２５ P ０．７５ S ４ More preferably, Li ７－ｘ P.S. ６－ｘ Cl ｘ (where 0≦x≦2), Li ７－ｘ P.S. ６－ｘ Br ｘ (where 0≦x≦2) and Li ７－ｘ P.S. ６－ｘ I ｘ (where 0≦x≦2), and more preferably Li ６ P.S. ５ Cl, Li ６ P.S. ５ Br and Li ６ P.S. ５ I, more preferably Li ６ P.S. ５ Contains Cl.

[0022] The oxide-based solid electrolyte is, for example, LiTi ２ (P.O. ４ ) ３ , LiZr ２ (P.O. ４ ) ３ , LiGe ２ (P.O. ４ ) ３ NASICON-type solid electrolyte materials such as (La ０．５＋ｘ Li ０．５－３ｘ ) TiO ３ Perovskite-type solid electrolyte materials such as Li ２ O-P ２ O ５ Material, Li ２ O-P ２ O ５ -Li ３ The material contains one or more selected from the group consisting of N materials and the like.

[0023] The polymer-based solid electrolyte includes one or more selected from the group consisting of polyether-based electrolyte materials such as polyethylene oxide, polypropylene oxide, ethylene oxide-propylene copolymer, and dimethylsiloxane-ethylene oxide copolymer; gel polymer electrolyte materials such as polyacrylonitrile, polyvinylidene fluoride, and vinylidene fluoride-hexafluoropropylene polymer; and polymer solid electrolyte materials using hyperbranched polymers.

[0024] The average particle diameter d of the solid electrolyte (A) in the volume-based particle size distribution measured by the laser diffraction scattering particle size distribution measurement method ５０ From the viewpoint of further improving the cycle characteristics of the all-solid-state battery, is preferably 0.5 μm or more and 30.0 μm or less, more preferably 1.0 μm or more and 20.0 μm or less, even more preferably 3.0 μm or more and 15.0 μm or less, even more preferably 4.0 μm or more and 10.0 μm or less, even more preferably 4.5 μm or more and 9.0 μm or less, even more preferably 5.0 μm or more and 8.0 μm or less, and even more preferably 5.5 μm or more and 7.0 μm or less.

[0025] When the entire solid electrolyte layer is taken as 100.0 parts by mass, the content of the solid electrolyte (A) in the solid electrolyte layer of the first embodiment is, from the viewpoint of further improving the cycle characteristics of the all-solid-state battery, preferably 50.0 parts by mass or more and 100.0 parts by mass or less, more preferably 60.0 parts by mass or more and 99.9 parts by mass or less, even more preferably 70.0 parts by mass or more and 99.5 parts by mass or less, still more preferably 85.0 parts by mass or more and 99.5 parts by mass or less, still more preferably 90.0 parts by mass or more and 99.0 parts by mass or less, still more preferably 93.0 parts by mass or more and 98.0 parts by mass or less, still more preferably 93.5 parts by mass or more and 97.5 parts by mass or less, and still more preferably 94.0 parts by mass or more and 97.0 parts by mass or less.

[0026] The solid electrolyte layer of the first embodiment may contain a binder resin. The binder resin for the solid electrolyte layer of the first embodiment preferably contains one or more selected from the group consisting of fluorine-based binder resins, rubber-based binder resins, and acrylic binder resins. Such binder resins may be in the form of an emulsion. When water is used as a solvent, it is preferable to use an aqueous binder resin and a thickener such as CMC (carboxymethyl cellulose) in combination.

[0027] When the entire solid electrolyte layer is taken as 100 parts by mass, the content of the binder resin in the solid electrolyte layer of the first embodiment is, from the viewpoint of further improving the cycle characteristics of the all-solid-state battery, preferably 0.5 parts by mass or more and 15.0 parts by mass or less, more preferably 1.0 parts by mass or more and 10.0 parts by mass or less, even more preferably 1.5 parts by mass or more and 8.0 parts by mass or less, still more preferably 2.0 parts by mass or more and 7.0 parts by mass or less, still more preferably 2.5 parts by mass or more and 6.5 parts by mass or less, and still more preferably 3.0 parts by mass or more and 6.0 parts by mass or less.

[0028] The thickness of the solid electrolyte layer of the first embodiment is preferably 1 μm or more and 150 μm or less, more preferably 5 μm or more and 100 μm or less, and even more preferably 10 μm or more and 80 μm or less.

[0029] The solid electrolyte layer of the first embodiment can be formed on the surface of the negative electrode by, for example, applying a slurry in which a solid electrolyte is dispersed in an organic solvent to the surface of a negative electrode active material layer formed on a negative electrode current collector, followed by drying. The organic solvent may include, for example, one or more selected from the group consisting of acetonitrile, xylene, dimethoxyethane, dimethyl carbonate, triethylamine or other tertiary amine solvents, heptane, hexane, tetrahydrofuran, toluene, N-methylpyrrolidone, as well as ether solvents, thiol solvents, butyl butyrate, and the like, and it is preferable that all of them have been dehydrated.

[0030] (Positive Electrode) The positive electrode of the first embodiment includes a positive electrode active material layer. The positive electrode active material layer of the first embodiment includes, for example, a positive electrode active material, and may further include one or more selected from the group consisting of a positive electrode binder resin, a solid electrolyte, and a conductive additive.

[0031] The positive electrode active material of the first embodiment is not particularly limited, and examples thereof include composite oxides of lithium and transition metals such as lithium-nickel composite oxide, lithium-cobalt composite oxide, lithium-manganese composite oxide, lithium-nickel-manganese composite oxide, lithium-nickel-cobalt composite oxide, lithium-nickel-aluminum composite oxide, lithium-nickel-cobalt-aluminum composite oxide, lithium-nickel-cobalt-manganese composite oxide, lithium-nickel-manganese-aluminum composite oxide, and lithium-nickel-cobalt-manganese-aluminum composite oxide; TiS ２ , FeS, MoS ２ transition metal sulfides such as MnO, V ２ O ５ , V ６ O １３ , TiO ２ The lithium phosphate oxide preferably contains one or more elements selected from the group consisting of transition metal oxides such as those mentioned above and olivine-type lithium phosphate oxides, and from the viewpoint of improving working potential, capacity, durability, and energy density, the lithium phosphate oxide preferably contains a lithium composite oxide having a layered rock-salt crystal structure, more preferably one or more elements selected from the group consisting of lithium-nickel composite oxide, lithium-cobalt composite oxide, lithium-nickel-aluminum composite oxide, and lithium-nickel-cobalt-manganese composite oxide, and even more preferably lithium-nickel-cobalt-manganese composite oxide. Here, the olivine-type lithium phosphate oxide contains, for example, at least one element selected from the group consisting of Mn, Cr, Co, Cu, Ni, V, Mo, Ti, Zn, Al, Ga, Mg, B, Nb, and Fe, as well as lithium, phosphorus, and oxygen.

[0032] The average particle diameter d of the positive electrode active material of the first embodiment ５０is preferably 0.1 μm or more and 30 μm or less, more preferably 0.3 μm or more and 20 μm or less, even more preferably 0.5 μm or more and 15 μm or less, and even more preferably 1.0 μm or more and 10.0 μm or less. ５０ means the particle size at 50% of the integrated value in the particle size distribution (volume basis) determined by the laser diffraction scattering method.

[0033] When the entire positive electrode active material layer is taken as 100.0 parts by mass, from the viewpoint of further improving the cycle characteristics of the all-solid-state battery, the content of the positive electrode active material in the positive electrode active material layer of the first embodiment is preferably 50.0 parts by mass or more and 90.0 parts by mass or less, more preferably 55.0 parts by mass or more and 90.0 parts by mass or less, even more preferably 60.0 parts by mass or more and 90.0 parts by mass or less, still more preferably 65.0 parts by mass or more and 90.0 parts by mass or less, still more preferably 70.0 parts by mass or more and 88.0 parts by mass or less, and still more preferably 75.0 parts by mass or more and 85.0 parts by mass or less.

[0034] The positive electrode active material layer of the first embodiment may contain one or more binder resins selected from the group consisting of fluorine-based binder resins, rubber-based binder resins, and acrylic binder resins. Such binder resins may be in the form of an emulsion. When water is used as the solvent, it is preferable to use an aqueous binder resin and a thickener such as CMC (carboxymethyl cellulose) in combination.

[0035] When the entire positive electrode active material layer is taken as 100 parts by mass, the content of the positive electrode binder resin in the positive electrode active material layer of the first embodiment is, from the viewpoint of further improving the cycle characteristics of the all-solid-state battery, preferably 0.5 parts by mass or more and 8.0 parts by mass or less, more preferably 0.8 parts by mass or more and 7.5 parts by mass or less, even more preferably 1.0 parts by mass or more and 7.0 parts by mass or less, and still more preferably 1.5 parts by mass or more and 6.5 parts by mass or less.

[0036] The solid electrolyte in the positive electrode active material layer of the first embodiment preferably includes one or more selected from the group consisting of a sulfide-based solid electrolyte, an oxide-based solid electrolyte, and a polymer-based solid electrolyte, and more preferably includes a sulfide-based solid electrolyte.

[0037] The oxide-based solid electrolyte is, for example, LiTi ２ (P.O. ４ ) ３ , LiZr ２ (P.O. ４ ) ３ , LiGe ２ (P.O. ４ ) ３ NASICON-type solid electrolyte materials such as (La ０．５＋ｘ Li ０．５－３ｘ ) TiO ３ Perovskite-type solid electrolyte materials such as Li ２ O-P ２ O ５ Material, Li ２ O-P ２ O ５ -Li ３ The material contains one or more selected from the group consisting of N materials and the like.

[0038] The sulfide-based solid electrolyte is, for example, Li ２ S-P ２ S ５ Material, Li ２ S-SiS ２ Material, Li ２ S-GeS ２ Material, Li ２ S-Al ２ S ３ Material, Li ２ S-SiS ２ -Li ３ P.O. ４ Material, Li ２ S-P ２ S ５ -GeS ２ Material, Li ２ S-Li ２ O-P ２ S ５ -SiS ２ Material, Li ２ S-GeS ２ -P ２ S ５ -SiS ２ Material, Li ２ S-SnS ２ -P ２ S ５ -SiS ２ Material, Li ２ S-P ２S ５ -Li ３ N material, Li ２ S ２＋Ｘ -P ４ S ３ Material, Li ２ S-P ２ S ５ -P ４ S ３ Material, LiPO ４ -Li ２ S-SiS material, Li ３ P.S. ４ , Li ３ P.O. ４ -Li ２ S-Si ２ S material, Li ３ P.O. ４ -Li ２ S-SiS ２ Material, LiI-Li ２ S-B ２ S ３ Material, LiI-Li ２ S-SiS ２ Material, LiI-Li ２ S-P ２ S ５ Material, LiI-Li ２ S-P ２ O ５ Material, LiI-Li ３ P.O. ４ -P ２ S ５ Li ２ S-P ２ S ５ -LiCl material, Li ７－ｘ P.S. ６－ｘ Cl ｘ (where 0≦x≦2), Li ７－ｘ P.S. ６－ｘ Br ｘ (where 0≦x≦2), Li ７－ｘ P.S. ６－ｘ I ｘ (where 0≦x≦2), Li １０ GeP ２ S １２ , and Li ３．２５ Ge ０．２５ P ０．７５ S ４ More preferably, Li７－ｘ P.S. ６－ｘ Cl ｘ (where 0≦x≦2), Li ７－ｘ P.S. ６－ｘ Br ｘ (where 0≦x≦2) and Li ７－ｘ P.S. ６－ｘ I ｘ (where 0≦x≦2), and more preferably Li ６ P.S. ５ Cl, Li ６ P.S. ５ Br and Li ６ P.S. ５ I, more preferably Li ６ P.S. ５ Contains Cl.

[0039] The polymer-based solid electrolyte includes one or more selected from the group consisting of polyether-based electrolyte materials such as polyethylene oxide, polypropylene oxide, ethylene oxide-propylene copolymer, and dimethylsiloxane-ethylene oxide copolymer; gel polymer electrolyte materials such as polyacrylonitrile, polyvinylidene fluoride, and vinylidene fluoride-hexafluoropropylene polymer; and polymer solid electrolyte materials using hyperbranched polymers.

[0040] When the entire cathode active material layer is taken as 100 parts by mass, the content of the solid electrolyte in the cathode active material layer in the first embodiment is, from the viewpoint of further improving the cycle characteristics of the all-solid-state battery, preferably 5.0 parts by mass or more and 40.0 parts by mass or less, more preferably 8.0 parts by mass or more and 35.0 parts by mass or less, even more preferably 10.0 parts by mass or more and 33.0 parts by mass or less, even more preferably 12.0 parts by mass or more and 30.0 parts by mass or less, and still more preferably 14.0 parts by mass or more and 28.0 parts by mass or less.

[0041] The positive electrode active material layer of the first embodiment preferably further contains a conductive additive, from the viewpoint of further improving the cycle characteristics of the all-solid-state battery. The conductive additive in the positive electrode active material layer of the first embodiment preferably contains one or more selected from the group consisting of carbon black, activated carbon, graphite, mesoporous carbon, fullerenes, carbon nanotubes, carbon nanofibers, and carbon brushes, and more preferably contains carbon black, from the viewpoint of further improving the cycle characteristics of the all-solid-state battery.

[0042] When the entire positive electrode active material layer is taken as 100 parts by mass, the content of the conductive additive in the positive electrode active material layer of the first embodiment is, from the viewpoint of further improving the cycle characteristics of the all-solid-state battery, preferably 0.1 parts by mass or more and 10.0 parts by mass or less, more preferably 0.3 parts by mass or more and 5.0 parts by mass or less, even more preferably 0.5 parts by mass or more and 4.0 parts by mass or less, even more preferably 0.8 parts by mass or more and 3.0 parts by mass or less, and still more preferably 1.0 parts by mass or more and 2.0 parts by mass or less.

[0043] The density of the positive electrode active material layer of the first embodiment is preferably 1.0 g / cm ３ 5.0g / cm or more ３ or less, more preferably 2.0 g / cm ３ 4.0g / cm or more ３ The following is the result.

[0044] The thickness of the positive electrode active material layer is not particularly limited, but is, for example, preferably from 1 μm to 150 μm, more preferably from 5 μm to 100 μm, and even more preferably from 10 μm to 80 μm.

[0045] The positive electrode of the first embodiment may further include a positive electrode current collector 3. The positive electrode current collector includes, for example, one or more materials selected from the group consisting of aluminum, stainless steel, nickel, titanium, and alloys thereof. The positive electrode current collector may be in the form of, for example, a foil, a flat plate, or a mesh. The thickness of the positive electrode current collector is, for example, 1 μm or more and 50 μm or less.

[0046] The negative electrode of the first embodiment includes a negative electrode active material layer. The negative electrode active material layer of the first embodiment includes, for example, a negative electrode active material and may further include one or more selected from the group consisting of a negative electrode binder resin, a solid electrolyte, and a conductive additive.

[0047] From the viewpoint of further improving the cycle characteristics of the all-solid-state battery, the negative electrode active material of the first embodiment preferably includes one or more negative electrode active materials selected from the group consisting of carbon materials, lithium-based metal materials, Si-based materials, and conductive polymer materials.

[0048] Examples of carbon materials include graphite, amorphous carbon, diamond-like carbon, fullerene, carbon nanotube, and carbon nanohorn. Examples of lithium-based metal materials include metallic lithium and lithium alloys. Examples of Si-based materials include Si and SiO. ２ , SiO ｘ (0<x≦2), Si-containing composite materials, etc. Examples of conductive polymer materials include polyacene, polyacetylene, polypyrrole, etc.

[0049] The content of the negative electrode active material in the negative electrode active material layer of the first embodiment is preferably 70 parts by mass or more and 100 parts by mass or less, more preferably 80 parts by mass or more and 100 parts by mass or less, and even more preferably 90 parts by mass or more and 100 parts by mass or less, when the total amount of the negative electrode active material layer is 100 parts by mass.

[0050] The negative electrode active material layer of the first embodiment may contain one or more binder resins selected from the group consisting of fluorine-based binder resins, rubber-based binder resins, and acrylic binder resins. Such binder resins may be in the form of an emulsion. When water is used as the solvent, it is preferable to use an aqueous binder resin and a thickener such as CMC (carboxymethyl cellulose) in combination.

[0051] The content of the binder resin in the negative electrode active material layer of the first embodiment may be, for example, 1 part by mass or more and 10 parts by mass or less, or 3 parts by mass or more and 6 parts by mass or less, when the total amount of the negative electrode active material layer is 100 parts by mass.

[0052] The solid electrolyte in the negative electrode active material layer of the first embodiment preferably includes one or more selected from the group consisting of a sulfide-based solid electrolyte, an oxide-based solid electrolyte, and a polymer-based solid electrolyte, and more preferably includes a sulfide-based solid electrolyte.

[0053] The oxide-based solid electrolyte is, for example, LiTi ２ (P.O. ４ ) ３ , LiZr ２ (P.O. ４ ) ３ , LiGe ２ (P.O. ４ ) ３ NASICON-type solid electrolyte materials such as (La ０．５＋ｘ Li ０．５－３ｘ ) TiO ３ Perovskite-type solid electrolyte materials such as Li ２ O-P ２ O ５ Material, Li ２ O-P ２ O ５ -Li ３ The material contains one or more selected from the group consisting of N materials and the like.

[0054] The sulfide-based solid electrolyte is, for example, Li ２ S-P ２ S ５ Material, Li ２ S-SiS ２ Material, Li ２ S-GeS ２ Material, Li ２ S-Al ２ S ３ Material, Li ２ S-SiS ２ -Li ３ P.O. ４ Material, Li ２ S-P ２ S ５ -GeS ２ Material, Li ２ S-Li ２ O-P ２ S ５ -SiS ２ Material, Li ２ S-GeS ２ -P ２ S ５-SiS ２ Material, Li ２ S-SnS ２ -P ２ S ５ -SiS ２ Material, Li ２ S-P ２ S ５ -Li ３ N material, Li ２ S ２＋Ｘ -P ４ S ３ Material, Li ２ S-P ２ S ５ -P ４ S ３ Material, LiPO ４ -Li ２ S-SiS material, Li ３ P.S. ４ , Li ３ P.O. ４ -Li ２ S-Si ２ S material, Li ３ P.O. ４ -Li ２ S-SiS ２ Material, LiI-Li ２ S-B ２ S ３ Material, LiI-Li ２ S-SiS ２ Material, LiI-Li ２ S-P ２ S ５ Material, LiI-Li ２ S-P ２ O ５ Material, LiI-Li ３ P.O. ４ -P ２ S ５ Li ２ S-P ２ S ５ -LiCl material, Li ７－ｘ P.S. ６－ｘ Cl ｘ (where 0≦x≦2), Li ７－ｘ P.S. ６－ｘ Br ｘ (where 0≦x≦2), Li ７－ｘ P.S. ６－ｘ I ｘ (where 0≦x≦2), Li１０ GeP ２ S １２ , and Li ３．２５ Ge ０．２５ P ０．７５ S ４ More preferably, Li ７－ｘ P.S. ６－ｘ Cl ｘ (where 0≦x≦2), Li ７－ｘ P.S. ６－ｘ Br ｘ (where 0≦x≦2) and Li ７－ｘ P.S. ６－ｘ I ｘ (where 0≦x≦2), and more preferably Li ６ P.S. ５ Cl, Li ６ P.S. ５ Br and Li ６ P.S. ５ I, more preferably Li ６ P.S. ５ Contains Cl.

[0055] The polymer-based solid electrolyte includes one or more selected from the group consisting of polyether-based electrolyte materials such as polyethylene oxide, polypropylene oxide, ethylene oxide-propylene copolymer, and dimethylsiloxane-ethylene oxide copolymer; gel polymer electrolyte materials such as polyacrylonitrile, polyvinylidene fluoride, and vinylidene fluoride-hexafluoropropylene polymer; and polymer solid electrolyte materials using hyperbranched polymers.

[0056] From the viewpoint of further improving the cycle characteristics of the all-solid-state battery, the conductive additive in the negative electrode active material layer of the first embodiment includes one or more selected from the group consisting of carbon black, activated carbon, graphite, mesoporous carbon, fullerenes, carbon nanotubes, carbon nanofibers, and carbon brushes, and more preferably includes carbon black.

[0057] The content of the conductive additive in the negative electrode active material layer of the first embodiment is 0.05 parts by mass or more and 10 parts by mass or less, preferably 0.5 parts by mass or more and 5.0 parts by mass or less, when the entire negative electrode active material layer is taken as 100 parts by mass, from the viewpoint of further improving the cycle characteristics of the all-solid-state battery.

[0058] In the negative electrode active material layer, electrode additives generally used for forming electrodes, such as thickeners, dispersants, and stabilizers, can be used as appropriate.

[0059] The density of the negative electrode active material layer in the first embodiment is preferably 0.5 g / cm ３ 3.0g / cm or more ３ or less, more preferably 1.2 g / cm ３ 2.0g / cm or more ３ The following is the result.

[0060] The thickness of the negative electrode active material layer in the first embodiment is preferably 1 μm or more and 150 μm or less, more preferably 5 μm or more and 100 μm or less, and even more preferably 10 μm or more and 80 μm or less.

[0061] The negative electrode of the first embodiment may further include a negative electrode current collector 4. The negative electrode current collector includes, for example, one or more materials selected from the group consisting of copper, stainless steel, nickel, titanium, and alloys thereof. The negative electrode current collector may be in the form of, for example, a foil, a flat plate, or a mesh. The thickness of the negative electrode current collector is, for example, 1 μm or more and 50 μm or less.

[0062] (Optional Configuration of All-Solid-State Battery) The all-solid-state battery of the first embodiment can further include exterior bodies 6 and 7. Examples of the exterior bodies include an aluminum laminate film, a strong aluminum can case, and a cylindrical aluminum exterior body.

[0063] The all-solid-state battery of the first embodiment may further include a positive electrode terminal 9 and a negative electrode terminal 8. Examples of the positive electrode terminal include a terminal made of aluminum or an aluminum alloy. Examples of the negative electrode terminal include a terminal made of copper, a copper alloy, or a nickel-plated copper or copper alloy.

[0064] <Method for manufacturing all-solid-state battery> The method for manufacturing an all-solid-state battery is not particularly limited, and known methods can be applied. First, the preparation of the negative electrode will be described. The negative electrode can be prepared by known methods. Regardless of the method used to prepare the negative electrode, it is preferably prepared in a low-moisture environment under dew point control in order to suppress adsorption of moisture into the solid electrolyte.

[0065] When using a negative electrode having a negative electrode active material layer formed on a negative electrode current collector, a slurry prepared by dispersing a negative electrode active material, a solid electrolyte, and a binder resin in a dehydrated organic solvent is applied to a portion or all of the surface of a negative electrode current collector such as copper foil, followed by drying to obtain a negative electrode precursor sheet. The obtained negative electrode precursor sheet can be compressed using a press molding method such as a roll press, a uniaxial press, a rubber press, or an isostatic press (CIP method, WIP method), to obtain a negative electrode sheet. The organic solvent preferably includes one or more solvents selected from the group consisting of tertiary amine solvents such as acetonitrile, xylene, dimethoxyethane, dimethyl carbonate, and triethylamine, as well as heptane, hexane, tetrahydrofuran, toluene, and N-methylpyrrolidone, as well as ether solvents, thiol solvents, and butyl butyrate, all of which are preferably dehydrated.

[0066] The negative electrode can be obtained by disposing a metallic lithium layer (negative electrode active material layer) such as lithium foil on part or all of a negative electrode current collector such as stainless steel foil, and then adhering them together by rolling or the like.

[0067] Next, a solid electrolyte layer is formed on the surface of the negative electrode. When a sulfide-based solid electrolyte is used, it is preferably formed in a low-moisture environment under dew point control to prevent moisture adsorption.

[0068] The solid electrolyte layer can be formed on the surface of the negative electrode by, for example, applying a slurry of a solid electrolyte dispersed in an organic solvent to the surface of a negative electrode active material layer formed on a negative electrode current collector, followed by drying. The organic solvent may include, for example, one or more selected from the group consisting of acetonitrile, xylene, dimethoxyethane, dimethyl carbonate, triethylamine, and other tertiary amine solvents, heptane, hexane, tetrahydrofuran, toluene, N-methylpyrrolidone, as well as ether solvents, thiol solvents, and butyl butyrate, and it is preferable that all of them have been dehydrated.

[0069] Next, the stacked negative electrode and solid electrolyte layer are compressed using a press molding method such as a vacuum laminator, roll press, uniaxial press, rubber press, or isostatic pressing (CIP method, WIP method), to obtain a negative electrode-solid electrolyte layer laminate. When the solid electrolyte layer is stacked together with a substrate layer such as a polyester sheet and pressurized, the substrate layer is peeled off from the solid electrolyte layer. In this case, it is also preferable to use a substrate layer whose surface is coated with a release agent such as silicone, so that the substrate layer can be easily peeled off from the solid electrolyte layer.

[0070] Next, the fabrication of the positive electrode will be described. Regardless of the method used to fabricate the positive electrode, it is preferable to fabricate the positive electrode in a low moisture environment under dew point control in order to suppress moisture adsorption.

[0071] The positive electrode of the first embodiment can be produced, for example, by a method (hereinafter sometimes referred to as Method A) in which the components constituting the positive electrode active material layer are dissolved or dispersed in a solvent to produce a positive electrode slurry, and the positive electrode slurry is applied to at least one surface of a positive electrode current collector, followed by drying and rolling. A roll press is preferably used for rolling, and the pressure during rolling is preferably 500 kg / cm or more and 10,000 kg / cm or less, more preferably 1,000 kg / cm or more and 8,000 kg / cm or less, and even more preferably 3,000 kg / cm or more and 6,000 kg / cm or less. Furthermore, the temperature during rolling is preferably 40°C or more and 100°C or less, more preferably 60°C or more and 95°C or less, and even more preferably 70°C or more and 90°C or less. The positive electrode of the first embodiment can also be produced, for example, by a method (hereinafter sometimes referred to as Method B) in which the positive electrode slurry is applied to a support, dried, and then peeled off from the support to obtain a film, which is then laminated on a positive electrode current collector. The solvent preferably includes one or more solvents selected from the group consisting of acetonitrile, xylene, dimethoxyethane, dimethyl carbonate, tertiary amine solvents such as triethylamine, heptane, hexane, tetrahydrofuran, toluene, N-methylpyrrolidone, ether solvents, thiol solvents, and butyl butyrate, and all of these solvents are preferably dehydrated.

[0072] A positive electrode is laminated on the negative electrode-solid electrolyte layer laminate to obtain an electrode laminate precursor. When a sulfide-based solid electrolyte is used as the solid electrolyte, the ionic conductivity of the solid electrolyte may decrease due to exposure to moisture. Therefore, it is preferable to obtain the electrode laminate precursor and then compress the electrode laminate precursor to obtain an electrode laminate. The method for compressing the electrode laminate precursor is preferably one or more methods selected from the group consisting of a vacuum laminator, a roll press, a uniaxial press, a rubber press, and an isostatic pressing (CIP method, WIP method). More preferably, compression is performed using a combination of a vacuum laminator and an isostatic pressing (CIP method). Furthermore, the temperature conditions for compressing the electrode laminate precursor are preferably 10°C or higher and 40°C or lower, more preferably 15°C or higher and 30°C or lower, and even more preferably 20°C or higher and 30°C or lower. The compression time of the electrode laminate precursor is preferably 0.5 minutes to 20 minutes, more preferably 0.5 minutes to 15 minutes, even more preferably 0.5 minutes to 10 minutes, and even more preferably 0.5 minutes to 5 minutes. Furthermore, the pressure conditions when compressing the electrode laminate precursor are preferably more than 300 MPa and not more than 1500 MPa, more preferably 350 MPa to 1400 MPa, even more preferably 375 MPa to 1200 MPa, and even more preferably 400 MPa to 1000 MPa. Furthermore, in the case of a manufacturing method that does not include a rolling step when producing a positive electrode, such as method B, the pressure conditions when compressing the electrode laminate precursor are preferably 500 MPa to 1500 MPa, more preferably 550 MPa to 1300 MPa, even more preferably 600 MPa to 1200 MPa, and even more preferably 650 MPa to 1100 MPa.

[0073] The resulting electrode laminate is preferably quickly sealed in an exterior housing. One end of a rectangular metal plate serving as a negative electrode terminal is attached to the negative electrode current collector, and one end of a rectangular metal terminal serving as a positive electrode terminal is attached to the positive electrode current collector, and then the electrode laminate is housed in an aluminum exterior housing. A resin layer such as polyolefin is preferably formed on at least the surface of the inner surface of the exterior housing facing the electrode laminate. The resin layer is heated to melt the resin and solidify it again, and the electrode laminate is sealed in the aluminum exterior housing. At this time, the other end of the positive electrode terminal and the other end of the negative electrode terminal are positioned so as to extend outside the exterior housing. A layer of resin of the same type or a different type from the resin used in the resin layer on the interior surface of the exterior housing can be provided in the areas where the positive electrode terminal and the negative electrode terminal contact the resin layer on the interior surface of the exterior housing.

[0074] <Battery Module> The battery module of the first embodiment includes the all-solid-state battery of the first embodiment. Since the all-solid-state battery of the first embodiment can improve the cycle characteristics, the battery module of the first embodiment can improve the cycle characteristics.

[0075] The battery module of the first embodiment preferably includes two or more all-solid-state batteries of the first embodiment connected in series or in parallel. The battery module of the first embodiment more preferably includes a housing capable of accommodating two or more all-solid-state batteries of the first embodiment connected in series or in parallel. The battery module of the first embodiment further preferably includes one or more components selected from the group consisting of a protection circuit that protects the all-solid-state battery from an overcurrent, a balancing circuit that equalizes the voltage between the electrodes of the all-solid-state battery, a controller that controls the all-solid-state battery, a cooler that can cool the all-solid-state battery, and a heater that can heat the all-solid-state battery.

[0076] The battery module of the first embodiment can be used in a battery system including a plurality of electrically connected battery modules and a battery control system, such as a battery pack, a stationary storage battery system, a power storage battery system for an automobile, a storage battery system for an auxiliary automobile, and an emergency power storage battery system.

[0077] The present invention is not limited to the first embodiment described above, and the present invention includes modifications and improvements within the scope of achieving the object of the present invention.

[0078] <<Second Embodiment>> Hereinafter, an all-solid-state battery and an all-solid-state battery module according to a second embodiment of the present invention will be described. <All-solid-state battery> Fig. 1 is a cross-sectional view showing an example of the structure of an all-solid-state battery 10 according to the second embodiment. The all-solid-state battery 10 according to the second embodiment includes, in this order, a positive electrode including a positive electrode active material layer 1, a solid electrolyte layer 5 including a solid electrolyte (A), and a negative electrode including a negative electrode active material layer 2, wherein the negative electrode active material layer 2 and the solid electrolyte layer 5 are in contact with each other, and the contact length of the interface between the negative electrode active material layer 2 and the solid electrolyte layer 5, as measured by the following method 2, is defined as L １Ｂ The straight line length is L ２Ｂ When this is done, L １Ｂ and L ２Ｂ The ratio (L １Ｂ / L ２Ｂ ) is 1.05 or more and 2.50 or less. １Ｂ / L ２Ｂ ) is preferably 1.20 or more and 2.50 or less, more preferably 1.30 or more and 2.30 or less, and even more preferably 1.40 or more and 2.20 or less, from the viewpoint of further improving the high rate discharge characteristics of the all-solid-state battery. １Ｂ / L ２Ｂ ) can be adjusted by adjusting, for example, the conditions for compressing the electrode laminate precursor in the process of producing the all-solid-state battery, the type and blending ratio of the negative electrode active material in the negative electrode active material layer, the type and blending ratio of the solid electrolyte in the solid electrolyte layer, etc., and in particular, １Ｂ / L ２Ｂ In order to set the thickness (μm) of the electrode laminate precursor to within the above range, the conditions for compressing the electrode laminate precursor in the process of producing an all-solid-state battery are important.

[0079] In the second embodiment, the contact length L in the cross section of the interface between the negative electrode active material layer and the solid electrolyte layer １Ｂ and the straight line length L ２Ｂcan be measured using image analysis software from a cross-sectional SEM image obtained using a scanning electron microscope (SEM) according to the following method 2. (Method 2) A cross-section of the negative electrode active material layer and the solid electrolyte layer is photographed using a scanning electron microscope (SEM) at a magnification of 2000x, with the direction in which the negative electrode active material layer and the solid electrolyte layer are stacked being the vertical direction, so that the interface between the negative electrode active material layer and the solid electrolyte layer includes 60 μm or more in the horizontal direction. From the obtained cross-sectional SEM image, the linear length L of the interface between the negative electrode active material layer and the solid electrolyte layer is calculated using image analysis software. ２Ｂ and contact length L １Ｂ Measure the contact length L １Ｂ is the length of the contact surface obtained by sampling the contact points between the negative electrode active material layer and the solid electrolyte in a 60 μm section in the horizontal direction in the cross-sectional SEM image and connecting each contact point with a straight line, and the straight line length L ２Ｂ is the contact length L １Ｂ When measuring the contact point, the two ends of the sampled contact points are connected by a straight line, and the length of the line obtained by projecting the line onto a horizontal plane is the length of the line.

[0080] As a result of the investigations by the present inventors, it was found that the contact length L １Ｂ and the straight line length L ２Ｂ The ratio (L １Ｂ / L ２Ｂ Based on the above findings, the present inventors have further conducted extensive research and found that there is a relationship between the L １Ｂ / L ２Ｂ The inventors have found that the high-rate discharge characteristics of an all-solid-state battery can be improved by adjusting L to the above range, and have completed the present invention. １Ｂ / L ２Ｂ The reason why the high rate discharge characteristics of the all-solid-state battery can be improved when L is within the above range is not clear, but １Ｂ / L ２Ｂ It is presumed that the mechanism by which the contact area between the negative electrode active material layer and the solid electrolyte falls within the above range is such that the high-rate discharge characteristics of the all-solid-state battery are improved.

[0081] Here, the contact length L between the interface between the negative electrode active material layer and the solid electrolyte layer in the all-solid-state battery of the second embodiment １Ｂ and the straight line length L ２Ｂ The contact length L １Ｂ The linear length L refers to the length of the contact surface obtained by horizontally sampling contact points between the negative electrode active material layer and the solid electrolyte layer at the interface between the negative electrode active material layer and the solid electrolyte layer in a cross-sectional SEM image taken using a scanning electron microscope (SEM) and connecting each contact point with a straight line, and means the actual length of the interface between the negative electrode active material layer 2 and the solid electrolyte layer 5. ２Ｂ is the contact length L of the interface between the negative electrode active material layer 2 and the solid electrolyte layer 5. １Ｂ The length of the projected line when projected onto a horizontal plane.

[0082] Here, referring to FIG. 2, the contact length L at the interface α between the negative electrode active material layer and the solid electrolyte layer is １Ｂ and the straight line length L ２Ｂ The ratio (L １Ｂ / L ２Ｂ 2 shows the measurement site of the contact length L at the interface α between the negative electrode active material layer and the solid electrolyte layer in the second embodiment. １Ｂ and the straight line length L ２Ｂ 1 is a top view of the interface α for explaining the measurement position of the anode active material layer 2 and the solid electrolyte layer 5. １ Select center line b １ A line b is parallel to ２ and b ３ Select center line b １ Center line b perpendicular to ４ Select center line b ４ A line b is parallel to ５ and b ６ The vertical distance between each line is d １ ~d ４ is, for example, 5 mm or more and 20 mm or less. １ and center line b ４ Area a centered on the intersection of １ Select center line b １ and line b５ Area a centered on the intersection of ２ Select center line b １ and line b ６ Area a centered on the intersection of ３ Select the line b ２ and center line b ４ Area a centered on the intersection of ４ Select the line b ２ and line b ５ Area a centered on the intersection of ５ Select the line b ２ and line b ６ Area a centered on the intersection of ６ Select the line b ３ and center line b ４ Area a centered on the intersection of ７ Select the line b ３ and line b ５ Area a centered on the intersection of ８ Select the line b ３ and line b ６ Area a centered on the intersection of ９ Then, select the area a １ ~a ９ A cross section was prepared, and a cross section SEM image was taken using a scanning electron microscope (SEM). １ ~a ９ Contact length L １Ｂ Then, in the region a １ ~a ９ The straight line length L ２Ｂ For example, in the area a １ ~a ９ The straight line length L ２Ｂ is the area a １ ~a ９ Then, the area a １ ~a ９ The straight line length L ２Ｂ The area a for the average value of １ ~a ９ Contact length L １Ｂ The ratio of the average value of (area a １ ~a ９ Contact length L １ＢAverage value / area a １ ~a ９ The straight line length L ２Ｂ This is used as the contact length L at the interface α between the negative electrode active material layer 2 and the solid electrolyte layer 5. １Ｂ and the straight line length L ２Ｂ The ratio (L １Ｂ / L ２Ｂ ) In addition, in the area a １ ~a ９ is a rectangular area of, for example, 0.2 mm x 0.2 mm.

[0083] As the scanning electron microscope (SEM), for example, an SU1500 manufactured by Hitachi High-Tech Corporation can be used. The magnification during measurement is, for example, 2000 times.

[0084] (Solid Electrolyte Layer) The solid electrolyte layer of the second embodiment contains a solid electrolyte (A).

[0085] The solid electrolyte (A) of the second embodiment preferably contains one or more selected from the group consisting of sulfide-based solid electrolytes, oxide-based solid electrolytes, and polymer-based solid electrolytes, from the viewpoint of further improving the high-rate discharge characteristics of the all-solid-state battery.

[0086] The sulfide-based solid electrolyte is, for example, Li ２ S-P ２ S ５ Material, Li ２ S-SiS ２ Material, Li ２ S-GeS ２ Material, Li ２ S-Al ２ S ３ Material, Li ２ S-SiS ２ -Li ３ P.O. ４ Material, Li ２ S-P ２ S ５ -GeS ２ Material, Li ２ S-Li ２ O-P ２ S ５ -SiS ２ Material, Li ２S-GeS ２ -P ２ S ５ -SiS ２ Material, Li ２ S-SnS ２ -P ２ S ５ -SiS ２ Material, Li ２ S-P ２ S ５ -Li ３ N Material, Li ２ S ２＋Ｘ -P ４ S ３ Material, Li ２ S-P ２ S ５ -P ４ S ３ Material, LiPO ４ -Li ２ S-SiS Material, Li ３ PS ４ , Li ３ PO ４ -Li ２ S-Si ２ S Material, Li ３ PO ４ -Li ２ S-SiS ２ Material, LiI-Li ２ S-B ２ S ３ Material, LiI-Li ２ S-SiS ２ Material, LiI-Li ２ S-P ２ S ５ Material, LiI-Li ２ S-P ２ O ５ Material, LiI-Li ３ PO ４ -P ２ S ５ Li ２ S-P ２ S ５ -LiCl Material, Li ７－ｘ PS ６－ｘ Cl ｘ (However, 0 ≤ x ≤ 2), Li ７－ｘ PS ６－ｘ Br ｘ (However, 0 ≤ x ≤ 2), Li ７－ｘ PS６－ｘ I ｘ (where 0≦x≦2), Li １０ GeP ２ S １２ , and Li ３．２５ Ge ０．２５ P ０．７５ S ４ More preferably, Li ７－ｘ P.S. ６－ｘ Cl ｘ (where 0≦x≦2), Li ７－ｘ P.S. ６－ｘ Br ｘ (where 0≦x≦2) and Li ７－ｘ P.S. ６－ｘ I ｘ (where 0≦x≦2), and more preferably Li ６ P.S. ５ Cl, Li ６ P.S. ５ Br and Li ６ P.S. ５ I, more preferably Li ６ P.S. ５ Contains Cl.

[0087] The oxide-based solid electrolyte is, for example, LiTi ２ (P.O. ４ ) ３ , LiZr ２ (P.O. ４ ) ３ , LiGe ２ (P.O. ４ ) ３ NASICON-type solid electrolyte materials such as (La ０．５＋ｘ Li ０．５－３ｘ ) TiO ３ Perovskite-type solid electrolyte materials such as Li ２ O-P ２ O ５ Material, Li ２ O-P ２ O ５ -Li ３ The material contains one or more selected from the group consisting of N materials and the like.

[0088] The polymer-based solid electrolyte includes one or more selected from the group consisting of polyether-based electrolyte materials such as polyethylene oxide, polypropylene oxide, ethylene oxide-propylene copolymer, and dimethylsiloxane-ethylene oxide copolymer; gel polymer electrolyte materials such as polyacrylonitrile, polyvinylidene fluoride, and vinylidene fluoride-hexafluoropropylene polymer; and polymer solid electrolyte materials using hyperbranched polymers.

[0089] The average particle diameter d of the solid electrolyte (A) in the volume-based particle size distribution measured by the laser diffraction scattering particle size distribution measurement method ５０ From the viewpoint of further improving the high rate discharge characteristics of the all-solid-state battery, is preferably 0.5 μm or more and 30.0 μm or less, more preferably 1.0 μm or more and 20.0 μm or less, even more preferably 3.0 μm or more and 15.0 μm or less, even more preferably 4.0 μm or more and 10.0 μm or less, even more preferably 4.5 μm or more and 9.0 μm or less, even more preferably 5.0 μm or more and 8.0 μm or less, and even more preferably 5.5 μm or more and 7.0 μm or less.

[0090] When the entire solid electrolyte layer is taken as 100.0 parts by mass, the content of the solid electrolyte (A) in the solid electrolyte layer of the second embodiment is, from the viewpoint of further improving the high-rate discharge characteristics of the all-solid-state battery, preferably 50.0 parts by mass or more and 100.0 parts by mass or less, more preferably 60.0 parts by mass or more and 99.9 parts by mass or less, even more preferably 70.0 parts by mass or more and 99.5 parts by mass or less, still more preferably 85.0 parts by mass or more and 99.5 parts by mass or less, still more preferably 90.0 parts by mass or more and 99.0 parts by mass or less, still more preferably 93.0 parts by mass or more and 98.0 parts by mass or less, still more preferably 93.5 parts by mass or more and 97.5 parts by mass or less, and still more preferably 94.0 parts by mass or more and 97.0 parts by mass or less.

[0091] The solid electrolyte layer of the second embodiment may contain a binder resin. The binder resin for the solid electrolyte layer of the second embodiment preferably contains one or more selected from the group consisting of fluorine-based binder resins, rubber-based binder resins, and acrylic binder resins. Such binder resins may be in the form of an emulsion. When water is used as a solvent, it is preferable to use an aqueous binder resin and a thickener such as CMC (carboxymethyl cellulose) in combination.

[0092] When the entire solid electrolyte layer is taken as 100 parts by mass, the content of the binder resin in the solid electrolyte layer of the second embodiment is, from the viewpoint of further improving the high-rate discharge characteristics of the all-solid-state battery, preferably 0.5 parts by mass or more and 15.0 parts by mass or less, more preferably 1.0 parts by mass or more and 10.0 parts by mass or less, even more preferably 1.5 parts by mass or more and 8.0 parts by mass or less, still more preferably 2.0 parts by mass or more and 7.0 parts by mass or less, still more preferably 2.5 parts by mass or more and 6.5 parts by mass or less, and still more preferably 3.0 parts by mass or more and 6.0 parts by mass or less.

[0093] The thickness of the solid electrolyte layer of the second embodiment is preferably 1 μm or more and 150 μm or less, more preferably 5 μm or more and 100 μm or less, and even more preferably 10 μm or more and 80 μm or less.

[0094] The solid electrolyte layer of the second embodiment can be produced on the surface of a negative electrode by, for example, applying a slurry in which a solid electrolyte is dispersed in an organic solvent to the surface of a negative electrode active material layer produced on a negative electrode current collector and drying the slurry. The organic solvent may include, for example, one or more solvents selected from the group consisting of acetonitrile, xylene, dimethoxyethane, dimethyl carbonate, triethylamine, and other tertiary amine solvents, heptane, hexane, tetrahydrofuran, toluene, N-methylpyrrolidone, as well as ether solvents, thiol solvents, and butyl butyrate, and preferably all of these solvents have been dehydrated. The solid electrolyte layer of the second embodiment can also be produced by, for example, applying the slurry to a support, drying it, and then peeling it off from the support to obtain a film, which is then laminated on the negative electrode.

[0095] (Positive Electrode) The positive electrode of the second embodiment includes a positive electrode active material layer. The positive electrode active material layer of the second embodiment includes, for example, a positive electrode active material and may further include one or more selected from the group consisting of a positive electrode binder resin, a solid electrolyte, and a conductive additive.

[0096] The positive electrode active material of the second embodiment is not particularly limited, and examples thereof include composite oxides of lithium and transition metals such as lithium-nickel composite oxide, lithium-cobalt composite oxide, lithium-manganese composite oxide, lithium-nickel-manganese composite oxide, lithium-nickel-cobalt composite oxide, lithium-nickel-aluminum composite oxide, lithium-nickel-cobalt-aluminum composite oxide, lithium-nickel-cobalt-manganese composite oxide, lithium-nickel-manganese-aluminum composite oxide, and lithium-nickel-cobalt-manganese-aluminum composite oxide; TiS ２ , FeS, MoS ２ transition metal sulfides such as MnO, V ２ O ５ , V ６ O １３ , TiO ２ The lithium phosphate oxide preferably contains one or more elements selected from the group consisting of transition metal oxides such as those mentioned above and olivine-type lithium phosphate oxides, and from the viewpoint of improving working potential, capacity, durability, and energy density, the lithium phosphate oxide preferably contains a lithium composite oxide having a layered rock-salt crystal structure, more preferably one or more elements selected from the group consisting of lithium-nickel composite oxide, lithium-cobalt composite oxide, lithium-nickel-aluminum composite oxide, and lithium-nickel-cobalt-manganese composite oxide, and even more preferably lithium-nickel-cobalt-manganese composite oxide. Here, the olivine-type lithium phosphate oxide contains, for example, at least one element selected from the group consisting of Mn, Cr, Co, Cu, Ni, V, Mo, Ti, Zn, Al, Ga, Mg, B, Nb, and Fe, as well as lithium, phosphorus, and oxygen.

[0097] The average particle diameter d of the positive electrode active material of the second embodiment ５０is preferably 0.1 μm or more and 30 μm or less, more preferably 0.3 μm or more and 20 μm or less, even more preferably 0.5 μm or more and 15 μm or less, and even more preferably 1.0 μm or more and 10.0 μm or less. ５０ means the particle size at 50% of the integrated value in the particle size distribution (volume basis) determined by the laser diffraction scattering method.

[0098] When the entire positive electrode active material layer is taken as 100.0 parts by mass, from the viewpoint of further improving the high-rate discharge characteristics of the all-solid-state battery, the content of the positive electrode active material in the positive electrode active material layer of the second embodiment is preferably 50.0 parts by mass or more and 90.0 parts by mass or less, more preferably 55.0 parts by mass or more and 90.0 parts by mass or less, even more preferably 60.0 parts by mass or more and 90.0 parts by mass or less, still more preferably 65.0 parts by mass or more and 90.0 parts by mass or less, still more preferably 70.0 parts by mass or more and 88.0 parts by mass or less, and still more preferably 75.0 parts by mass or more and 85.0 parts by mass or less.

[0099] The positive electrode active material layer of the second embodiment may contain one or more positive electrode binder resins selected from the group consisting of fluorine-based binder resins, rubber-based binder resins, and acrylic binder resins. Such positive electrode binder resins may be in the form of an emulsion. When water is used as the solvent, it is preferable to use the aqueous binder resin in combination with a thickener such as CMC (carboxymethyl cellulose).

[0100] When the entire positive electrode active material layer is taken as 100 parts by mass, the content of the positive electrode binder resin in the positive electrode active material layer of the second embodiment is, from the viewpoint of further improving the high-rate discharge characteristics of the all-solid-state battery, preferably 0.5 parts by mass or more and 8.0 parts by mass or less, more preferably 0.8 parts by mass or more and 7.5 parts by mass or less, even more preferably 1.0 parts by mass or more and 7.0 parts by mass or less, and still more preferably 1.5 parts by mass or more and 6.5 parts by mass or less.

[0101] The solid electrolyte in the positive electrode active material layer of the second embodiment preferably includes one or more selected from the group consisting of a sulfide-based solid electrolyte, an oxide-based solid electrolyte, and a polymer-based solid electrolyte, and more preferably includes a sulfide-based solid electrolyte.

[0102] The oxide-based solid electrolyte is, for example, LiTi ２ (P.O. ４ ) ３ , LiZr ２ (P.O. ４ ) ３ , LiGe ２ (P.O. ４ ) ３ NASICON-type solid electrolyte materials such as (La ０．５＋ｘ Li ０．５－３ｘ ) TiO ３ Perovskite-type solid electrolyte materials such as Li ２ O-P ２ O ５ Material, Li ２ O-P ２ O ５ -Li ３ The material contains one or more selected from the group consisting of N materials and the like.

[0103] The sulfide-based solid electrolyte is, for example, Li ２ S-P ２ S ５ Material, Li ２ S-SiS ２ Material, Li ２ S-GeS ２ Material, Li ２ S-Al ２ S ３ Material, Li ２ S-SiS ２ -Li ３ P.O. ４ Material, Li ２ S-P ２ S ５ -GeS ２ Material, Li ２ S-Li ２ O-P ２ S ５ -SiS ２ Material, Li ２ S-GeS ２ -P ２ S ５ -SiS ２ Material, Li ２ S-SnS ２ -P ２ S ５ -SiS ２ Material, Li ２ S-P ２S ５ -Li ３ N material, Li ２ S ２＋Ｘ -P ４ S ３ Material, Li ２ S-P ２ S ５ -P ４ S ３ Material, LiPO ４ -Li ２ S-SiS material, Li ３ P.S. ４ , Li ３ P.O. ４ -Li ２ S-Si ２ S material, Li ３ P.O. ４ -Li ２ S-SiS ２ Material, LiI-Li ２ S-B ２ S ３ Material, LiI-Li ２ S-SiS ２ Material, LiI-Li ２ S-P ２ S ５ Material, LiI-Li ２ S-P ２ O ５ Material, LiI-Li ３ P.O. ４ -P ２ S ５ Li ２ S-P ２ S ５ -LiCl material, Li ７－ｘ P.S. ６－ｘ Cl ｘ (where 0≦x≦2), Li ７－ｘ P.S. ６－ｘ Br ｘ (where 0≦x≦2), Li ７－ｘ P.S. ６－ｘ I ｘ (where 0≦x≦2), Li １０ GeP ２ S １２ , and Li ３．２５ Ge ０．２５ P ０．７５ S ４ More preferably, Li７－ｘ P.S. ６－ｘ Cl ｘ (where 0≦x≦2), Li ７－ｘ P.S. ６－ｘ Br ｘ (where 0≦x≦2) and Li ７－ｘ P.S. ６－ｘ I ｘ (where 0≦x≦2), and more preferably Li ６ P.S. ５ Cl, Li ６ P.S. ５ Br and Li ６ P.S. ５ I, more preferably Li ６ P.S. ５ Contains Cl.

[0104] The polymer-based solid electrolyte includes one or more selected from the group consisting of polyether-based electrolyte materials such as polyethylene oxide, polypropylene oxide, ethylene oxide-propylene copolymer, and dimethylsiloxane-ethylene oxide copolymer; gel polymer electrolyte materials such as polyacrylonitrile, polyvinylidene fluoride, and vinylidene fluoride-hexafluoropropylene polymer; and polymer solid electrolyte materials using hyperbranched polymers.

[0105] When the entire positive electrode active material layer is taken as 100 parts by mass, the content of the solid electrolyte in the positive electrode active material layer in the second embodiment is, from the viewpoint of further improving the high-rate discharge characteristics of the all-solid-state battery, preferably 5.0 parts by mass or more and 40.0 parts by mass or less, more preferably 8.0 parts by mass or more and 35.0 parts by mass or less, even more preferably 10.0 parts by mass or more and 33.0 parts by mass or less, even more preferably 12.0 parts by mass or more and 30.0 parts by mass or less, and still more preferably 14.0 parts by mass or more and 28.0 parts by mass or less.

[0106] The positive electrode active material layer of the second embodiment preferably further contains a conductive additive, from the viewpoint of further improving the high-rate discharge characteristics of the all-solid-state battery. The conductive additive in the positive electrode active material layer of the second embodiment preferably contains one or more selected from the group consisting of carbon black, activated carbon, graphite, mesoporous carbon, fullerenes, carbon nanotubes, carbon nanofibers, and carbon brushes, and more preferably contains carbon black, from the viewpoint of further improving the high-rate discharge characteristics of the all-solid-state battery.

[0107] When the entire positive electrode active material layer is taken as 100 parts by mass, the content of the conductive additive in the positive electrode active material layer of the second embodiment is, from the viewpoint of further improving the high-rate discharge characteristics of the all-solid-state battery, preferably 0.1 parts by mass or more and 10.0 parts by mass or less, more preferably 0.3 parts by mass or more and 5.0 parts by mass or less, even more preferably 0.5 parts by mass or more and 4.0 parts by mass or less, even more preferably 0.8 parts by mass or more and 3.0 parts by mass or less, and still more preferably 1.0 parts by mass or more and 2.0 parts by mass or less.

[0108] The density of the positive electrode active material layer of the second embodiment is preferably 1.0 g / cm ３ 5.0g / cm or more ３ or less, more preferably 2.0 g / cm ３ 4.0g / cm or more ３ The following is the result.

[0109] The thickness of the positive electrode active material layer is not particularly limited, but is, for example, preferably from 1 μm to 150 μm, more preferably from 5 μm to 100 μm, and even more preferably from 10 μm to 80 μm.

[0110] The positive electrode of the second embodiment may further include a positive electrode current collector 3. The positive electrode current collector includes, for example, one or more materials selected from the group consisting of aluminum, stainless steel, nickel, titanium, and alloys thereof. The positive electrode current collector may be in the form of, for example, a foil, a flat plate, or a mesh. The thickness of the positive electrode current collector is, for example, 1 μm or more and 50 μm or less.

[0111] The negative electrode of the second embodiment includes a negative electrode active material layer. The negative electrode active material layer of the second embodiment includes, for example, a negative electrode active material and may further include one or more selected from the group consisting of a negative electrode binder resin, a solid electrolyte, and a conductive additive.

[0112] From the viewpoint of further improving the high-rate discharge characteristics of the all-solid-state battery, the negative electrode active material of the second embodiment preferably includes one or more negative electrode active materials selected from the group consisting of carbon materials, lithium-based metal materials, Si-based materials, and conductive polymer materials.

[0113] Examples of carbon materials include graphite, amorphous carbon, diamond-like carbon, fullerene, carbon nanotube, and carbon nanohorn. Examples of lithium-based metal materials include metallic lithium and lithium alloys such as lithium magnesium alloy. Examples of Si-based materials include Si and SiO. ２ , SiO ｘ (0<x≦2), Si-containing composite materials, etc. Examples of conductive polymer materials include polyacene, polyacetylene, polypyrrole, etc.

[0114] The content of the negative electrode active material in the negative electrode active material layer of the second embodiment is preferably 70 parts by mass or more and 100 parts by mass or less, more preferably 80 parts by mass or more and 100 parts by mass or less, and even more preferably 90 parts by mass or more and 100 parts by mass or less, when the total amount of the negative electrode active material layer is 100 parts by mass.

[0115] The negative electrode active material layer of the second embodiment may contain one or more negative electrode binder resins selected from the group consisting of fluorine-based binder resins, rubber-based binder resins, and acrylic binder resins. Such negative electrode binder resins may be in the form of an emulsion. When water is used as the solvent, it is preferable to use the aqueous binder resin in combination with a thickener such as CMC (carboxymethyl cellulose).

[0116] The content of the binder resin in the negative electrode active material layer of the second embodiment may be, for example, 1 part by mass or more and 10 parts by mass or less, or 3 parts by mass or more and 6 parts by mass or less, when the total amount of the negative electrode active material layer is 100 parts by mass.

[0117] The solid electrolyte in the negative electrode active material layer of the second embodiment preferably includes one or more selected from the group consisting of oxide-based solid electrolytes, sulfide-based solid electrolytes, and polymer-based solid electrolytes, and more preferably includes a sulfide-based solid electrolyte.

[0118] The oxide-based solid electrolyte is, for example, LiTi ２ (P.O. ４ ) ３ , LiZr ２ (P.O. ４ ) ３ , LiGe ２ (P.O. ４ ) ３ NASICON-type solid electrolyte materials such as (La ０．５＋ｘ Li ０．５－３ｘ ) TiO ３ Perovskite-type solid electrolyte materials such as Li ２ O-P ２ O ５ Material, Li ２ O-P ２ O ５ -Li ３ The material contains one or more selected from the group consisting of N materials and the like.

[0119] The sulfide-based solid electrolyte is, for example, Li ２ S-P ２ S ５ Material, Li ２ S-SiS ２ Material, Li ２ S-GeS ２ Material, Li ２ S-Al ２ S ３ Material, Li ２ S-SiS ２ -Li ３ P.O. ４ Material, Li ２ S-P ２ S ５ -GeS ２ Material, Li ２ S-Li ２ O-P ２ S ５ -SiS ２ Material, Li ２ S-GeS ２ -P２ S ５ -SiS ２ material, Li ２ S-SnS ２ -P ２ S ５ -SiS ２ material, Li ２ S-P ２ S ５ -Li ３ N material, Li ２ S ２＋Ｘ -P ４ S ３ material, Li ２ S-P ２ S ５ -P ４ S ３ material, LiPO ４ -Li ２ S-SiS material, Li ３ PS ４ 、Li ３ PO ４ -Li ２ S-Si ２ S material, Li ３ PO ４ -Li ２ S-SiS ２ material, LiI-Li ２ S-B ２ S ３ material, LiI-Li ２ S-SiS ２ material, LiI-Li ２ S-P ２ S ５ material, LiI-Li ２ S-P ２ O ５ material, LiI-Li ３ PO ４ -P ２ S ５ Li ２ S-P ２ S ５ -LiCl material, Li ７－ｘ PS ６－ｘ Cl ｘ (where 0 ≦ x ≦ 2), Li ７－ｘ PS ６－ｘ Br ｘ (where 0 ≦ x ≦ 2), Li ７－ｘ PS ６－ｘ Iｘ (where 0≦x≦2), Li １０ GeP ２ S １２ , and Li ３．２５ Ge ０．２５ P ０．７５ S ４ More preferably, Li ７－ｘ P.S. ６－ｘ Cl ｘ (where 0≦x≦2), Li ７－ｘ P.S. ６－ｘ Br ｘ (where 0≦x≦2) and Li ７－ｘ P.S. ６－ｘ I ｘ (where 0≦x≦2), and more preferably Li ６ P.S. ５ Cl, Li ６ P.S. ５ Br and Li ６ P.S. ５ I, more preferably Li ６ P.S. ５ Contains Cl.

[0120] The polymer-based solid electrolyte includes one or more selected from the group consisting of polyether-based electrolyte materials such as polyethylene oxide, polypropylene oxide, ethylene oxide-propylene copolymer, and dimethylsiloxane-ethylene oxide copolymer; gel polymer electrolyte materials such as polyacrylonitrile, polyvinylidene fluoride, and vinylidene fluoride-hexafluoropropylene polymer; and polymer solid electrolyte materials using hyperbranched polymers.

[0121] From the viewpoint of further improving the high-rate discharge characteristics of the all-solid-state battery, the conductive additive in the negative electrode active material layer of the second embodiment includes one or more selected from the group consisting of carbon black, activated carbon, graphite, mesoporous carbon, fullerenes, carbon nanotubes, carbon nanofibers, and carbon brushes, and more preferably includes carbon black.

[0122] The content of the conductive additive in the negative electrode active material layer of the second embodiment is 0.05 parts by mass or more and 10 parts by mass or less, preferably 0.5 parts by mass or more and 5.0 parts by mass or less, when the entire negative electrode active material layer is taken as 100 parts by mass, from the viewpoint of further improving the high-rate discharge characteristics of the all-solid-state battery.

[0123] In the negative electrode active material layer, electrode additives generally used for forming electrodes, such as thickeners, dispersants, and stabilizers, can be used as appropriate.

[0124] The density of the negative electrode active material layer of the second embodiment is preferably 0.5 g / cm ３ 3.0g / cm or more ３ or less, more preferably 1.2 g / cm ３ 2.0g / cm or more ３ The following is the result.

[0125] The negative electrode active material layer of the second embodiment includes a lithium layer on the surface in contact with the solid electrolyte layer, from the viewpoint of further improving the high-rate discharge characteristics of the all-solid-state battery. Such a structure can be formed, for example, by using a lithium metal material such as lithium foil as the anode material constituting the negative electrode active material layer. Furthermore, the negative electrode active material layer of the second embodiment includes a layer formed of an alloy containing lithium and magnesium on the surface in contact with the solid electrolyte layer, from the viewpoint of further improving the high-rate discharge characteristics of the all-solid-state battery. Such a structure can be formed, for example, by using a lithium-magnesium alloy material such as lithium-magnesium alloy foil as the anode material constituting the negative electrode active material layer.

[0126] The thickness of the negative electrode active material layer of the second embodiment is preferably 1 μm or more and 150 μm or less, more preferably 5 μm or more and 100 μm or less, and even more preferably 10 μm or more and 80 μm or less.

[0127] The negative electrode of the second embodiment may further include a negative electrode current collector 4. The negative electrode current collector includes, for example, one or more materials selected from the group consisting of copper, stainless steel, nickel, titanium, and alloys thereof. The negative electrode current collector may be in the form of, for example, a foil, a flat plate, or a mesh. The thickness of the negative electrode current collector is, for example, 1 μm or more and 50 μm or less.

[0128] (Optional Configuration of All-Solid-State Battery) The all-solid-state battery of the second embodiment can further include exterior bodies 6 and 7. Examples of the exterior bodies include an aluminum laminate film, a strong aluminum can case, and a cylindrical aluminum exterior body.

[0129] The all-solid-state battery of the second embodiment may further include a positive electrode terminal 9 and a negative electrode terminal 8. Examples of the positive electrode terminal include a terminal made of aluminum or an aluminum alloy. Examples of the negative electrode terminal include a terminal made of copper, a copper alloy, or a nickel-plated copper or copper alloy.

[0130] <Method for manufacturing all-solid-state battery> The method for manufacturing an all-solid-state battery is not particularly limited, and known methods can be applied. First, the preparation of the negative electrode will be described. The negative electrode can be prepared by known methods. Regardless of the method used to prepare the negative electrode, it is preferably prepared in a low-moisture environment under dew point control in order to suppress adsorption of moisture into the solid electrolyte.

[0131] When using a negative electrode having a negative electrode active material layer formed on a negative electrode current collector, a slurry prepared by dispersing a negative electrode active material, a solid electrolyte, and a binder resin in a dehydrated organic solvent is applied to a portion or all of the surface of a negative electrode current collector such as copper foil, followed by drying to obtain a negative electrode precursor sheet. The obtained negative electrode precursor sheet can be compressed using a press molding method such as a roll press, a uniaxial press, a rubber press, or an isostatic press (CIP method, WIP method), to obtain a negative electrode sheet. The organic solvent preferably includes one or more solvents selected from the group consisting of tertiary amine solvents such as acetonitrile, xylene, dimethoxyethane, dimethyl carbonate, and triethylamine, as well as heptane, hexane, tetrahydrofuran, toluene, and N-methylpyrrolidone, as well as ether solvents, thiol solvents, and butyl butyrate, all of which are preferably dehydrated.

[0132] The negative electrode can be obtained by disposing a metallic lithium layer (negative electrode active material layer) such as lithium foil or lithium-magnesium alloy foil on a part or all of a negative electrode current collector such as stainless steel foil, and then adhering them together by rolling, etc. Alternatively, the negative electrode can be obtained by using lithium foil, lithium-magnesium alloy foil, or the like as is.

[0133] Next, a solid electrolyte layer is formed on the surface of the negative electrode. When a sulfide-based solid electrolyte is used, it is preferably formed in a low-moisture environment under dew point control to prevent moisture adsorption.

[0134] The solid electrolyte layer can be produced on the surface of the negative electrode by, for example, applying a slurry in which a solid electrolyte is dispersed in an organic solvent to the surface of a negative electrode active material layer produced on a negative electrode current collector and drying the slurry. The organic solvent may include, for example, one or more solvents selected from the group consisting of tertiary amine solvents such as acetonitrile, xylene, dimethoxyethane, dimethyl carbonate, and triethylamine, as well as ether solvents, thiol solvents, and butyl butyrate, and preferably all solvents have been dehydrated. The solid electrolyte layer of the second embodiment can also be produced by, for example, applying the slurry to a support, drying the slurry, and then peeling the resulting film from the support and laminating it on the negative electrode.

[0135] Next, the stacked negative electrode and solid electrolyte layer are compressed using a press molding method such as a vacuum laminator, roll press, uniaxial press, rubber press, or isostatic pressing (CIP method, WIP method), to obtain a negative electrode-solid electrolyte layer laminate. When the solid electrolyte layer is stacked together with a substrate layer such as a polyester sheet and pressurized, the substrate layer is peeled off from the solid electrolyte layer. In this case, it is also preferable to use a substrate layer whose surface is coated with a release agent such as silicone, so that the substrate layer can be easily peeled off from the solid electrolyte layer.

[0136] Next, the fabrication of the positive electrode will be described. Regardless of the method used to fabricate the positive electrode, it is preferable to fabricate the positive electrode in a low moisture environment under dew point control in order to suppress moisture adsorption.

[0137] The positive electrode of the second embodiment can be produced, for example, by dissolving or dispersing the components constituting the positive electrode active material layer in a solvent to produce a positive electrode slurry, applying the positive electrode slurry to at least one surface of a positive electrode current collector, drying, and rolling. Rolling is preferably performed using a roll press, and the pressure during rolling is preferably 500 kg / cm or more and 10,000 kg / cm or less, more preferably 1,000 kg / cm or more and 8,000 kg / cm or less, and even more preferably 3,000 kg / cm or more and 6,000 kg / cm or less. Furthermore, the temperature during rolling is preferably 40°C or more and 100°C or less, more preferably 60°C or more and 95°C or less, and even more preferably 70°C or more and 90°C or less. The positive electrode of the second embodiment can also be produced, for example, by applying the positive electrode slurry to a support, drying it, and then peeling it off from the support to obtain a film, which is then laminated on a positive electrode current collector. The solvent preferably includes one or more solvents selected from the group consisting of acetonitrile, xylene, dimethoxyethane, dimethyl carbonate, tertiary amine solvents such as triethylamine, heptane, hexane, tetrahydrofuran, toluene, N-methylpyrrolidone, ether solvents, thiol solvents, and butyl butyrate, and all of these solvents are preferably dehydrated.

[0138] A positive electrode is laminated on the negative electrode-solid electrolyte layer laminate to obtain an electrode laminate precursor. When a sulfide-based solid electrolyte is used as the solid electrolyte, the ionic conductivity of the solid electrolyte may decrease due to exposure to moisture. Therefore, it is preferable to obtain the electrode laminate precursor and then compress the electrode laminate precursor to obtain an electrode laminate. The method for compressing the electrode laminate precursor is preferably one or more methods selected from the group consisting of a vacuum laminator, a roll press, a uniaxial press, a rubber press, and an isostatic pressing (CIP method, WIP method). More preferably, compression is performed using a combination of a vacuum laminator and an isostatic pressing (CIP method). Furthermore, the temperature conditions for compressing the electrode laminate precursor are preferably 10°C or higher and 40°C or lower, more preferably 15°C or higher and 30°C or lower, and even more preferably 20°C or higher and 30°C or lower. The compression time of the electrode laminate precursor is preferably 0.5 to 20 minutes, more preferably 0.5 to 15 minutes, even more preferably 0.5 to 10 minutes, and even more preferably 0.5 to 5 minutes. Furthermore, the pressure conditions when compressing the electrode laminate precursor are preferably 80 to 1500 MPa, more preferably 130 to 1400 MPa, even more preferably 200 to 1200 MPa, even more preferably 250 to 1100 MPa, and even more preferably 300 to 1100 MPa.

[0139] The resulting electrode laminate is preferably quickly sealed in an exterior housing. One end of a rectangular metal plate serving as a negative electrode terminal is attached to the negative electrode current collector, and one end of a rectangular metal terminal serving as a positive electrode terminal is attached to the positive electrode current collector, and then the electrode laminate is housed in an aluminum exterior housing. A resin layer such as polyolefin is preferably formed on at least the surface of the inner surface of the exterior housing facing the electrode laminate. The resin layer is heated to melt the resin and solidify it again, and the electrode laminate is sealed in the aluminum exterior housing. At this time, the other end of the positive electrode terminal and the other end of the negative electrode terminal are positioned so as to extend outside the exterior housing. A layer of resin of the same type or a different type from the resin used in the resin layer on the interior surface of the exterior housing can be provided in the areas where the positive electrode terminal and the negative electrode terminal contact the resin layer on the interior surface of the exterior housing.

[0140] <Battery Module> The battery module of the second embodiment includes the all-solid-state battery of the second embodiment. Since the all-solid-state battery of the second embodiment can improve the high-rate discharge characteristics, the battery module of the second embodiment can improve the high-rate discharge characteristics.

[0141] The battery module of the second embodiment preferably includes two or more all-solid-state batteries of the present embodiment connected in series or in parallel. The battery module of the second embodiment more preferably includes a housing capable of accommodating two or more all-solid-state batteries of the second embodiment connected in series or in parallel. The battery module of the second embodiment further preferably includes one or more components selected from the group consisting of a protection circuit that protects the all-solid-state battery from an overcurrent, a balancing circuit that equalizes the voltage between the electrodes of the all-solid-state battery, a controller that controls the all-solid-state battery, a cooler that can cool the all-solid-state battery, and a heater that can heat the all-solid-state battery.

[0142] The battery module of the second embodiment can be used in a battery system including a plurality of electrically connected battery modules and a battery control system, such as a battery pack, a stationary storage battery system, a power storage battery system for an automobile, a storage battery system for an automobile auxiliary device, and an emergency power storage battery system.

[0143] The present invention is not limited to the second embodiment described above, and any modifications and improvements that can achieve the object of the present invention are included in the present invention.

[0144] The present invention is not limited to the above-described embodiments, and includes modifications and improvements within the scope of achieving the object of the present invention.

[0145] Additionally, the present invention also includes configurations that combine the configurations of the above-described embodiments.

[0146] Hereinafter, the first embodiment of the present invention will be specifically described with reference to examples, but the first embodiment of the present invention is not limited to the examples.

[0147] <<Examples 1A to 2A and Comparative Example 1A>> The first embodiment of the present invention will be described in detail below with reference to Examples 1A to 2A and Comparative Example 1A. Note that the first embodiment is not limited to the descriptions of these examples.

[0148] Example 1A An all-solid-state battery was fabricated by the following method.

[0149] [I] Preparation of anode-solid electrolyte layer laminate (1) A foil (manufactured by Honjo Metals Co., Ltd.) with a 20 μm-thick lithium metal layer formed on the surface of a 10 μm-thick stainless steel anode current collector was prepared as the anode. (2) A slurry of a solid electrolyte and a binder resin dispersed in xylene was applied to the surface of a polyester film primarily composed of polyester, followed by drying to form a solid electrolyte layer on the polyester film. Next, the solid electrolyte layer was laminated on the anode together with the polyester film so that the resulting solid electrolyte layer contacted the surface of the lithium metal layer of the anode, yielding a cathode-solid electrolyte layer laminate. (3) The anode-solid electrolyte layer laminate obtained in (2) above was vacuum-sealed using a vacuum laminator and held at room temperature (25°C) for 1 minute. Next, the anode-solid electrolyte layer laminate was removed from the vacuum laminator and compressed by isostatic pressing (CIP) at room temperature (25°C) under a pressure of 300 MPa for 1 minute to yield a cathode-solid electrolyte layer laminate. The size of the negative electrode-solid electrolyte layer laminate was 26 mm x 26 mm. (4) The polyester film was peeled off from the solid electrolyte layer to obtain a negative electrode-solid electrolyte layer laminate.

[0150] [II] Lamination of Positive Electrode and Negative Electrolyte Layer Laminate (1) A positive electrode active material, a solid electrolyte, a conductive additive, and a binder resin were dispersed in butyl butyrate to obtain a slurry. The obtained slurry was then applied to a 10 μm thick aluminum foil and dried to form a positive electrode active material layer. A positive electrode was then obtained by hot roll pressing under conditions of 80°C and 5000 kg / cm. (2) The positive electrode obtained in (1) above was cut into a 20 mm x 20 mm size, and the positive electrode and the negative electrode-solid electrolyte layer laminate were laminated such that the positive electrode active material layer was in contact with the solid electrolyte layer of the negative electrode-solid electrolyte layer laminate prepared in [I] above, thereby obtaining an electrode laminate precursor. The number of layers of the positive electrode and the negative electrode-solid electrolyte layer laminate was one each.

[0151] [III] Preparation of Electrode Laminate The electrode laminate precursor obtained in [II] above was vacuum-sealed using a vacuum laminator and held at room temperature (25° C.) for 1 minute. The electrode laminate precursor was then removed from the vacuum laminator and compressed by a CIP method at room temperature (25° C.) under a pressure of 400 MPa for 1 minute to obtain an electrode laminate.

[0152] [IV] Encapsulation in Exterior Body The electrode laminate obtained in [III] above was enclosed in an aluminum exterior body (manufactured by Dai Nippon Printing Co., Ltd.) by the method described in the first embodiment, and an all-solid-state battery in which the positive electrode terminal and the negative electrode terminal were extended to the outside of the exterior body was obtained.

[0153] Example 2A An all-solid-state battery was produced in the same manner as in Example 1A, except that the hot roll press was not performed when producing the positive electrode, and the pressure conditions for the electrode laminate precursor by the CIP method were changed to the conditions shown in Table 1A.

[0154] Comparative Example 1A An all-solid-state battery was produced in the same manner as in Example 1A, except that the conditions for pressing the electrode laminate precursor by the CIP method were changed to the conditions shown in Table 1A.

[0155] <Average particle diameter d of the solid electrolyte and the positive electrode active material ５０ Measurement method of the average particle diameter d of the solid electrolyte and the positive electrode active material at which the cumulative volume is 50% in the volume-based particle size distribution measured by the laser diffraction scattering particle size distribution measurement method ５０ were measured using a laser diffraction / scattering particle size distribution analyzer (MT3000, manufactured by Microtrac). Here, for the solid electrolyte, the solid electrolyte was suspended in a dispersion medium (butyl butyrate) and ultrasonically dispersed, followed by measurement. For the positive electrode active material, the positive electrode active material was suspended in a dispersion medium (0.1% by mass sodium hexametaphosphate aqueous solution) and ultrasonically dispersed, followed by measurement. Each measurement was performed five times, and the average value was used.

[0156] <Evaluation of the Interface Between the Positive Electrode Active Material Layer and the Solid Electrolyte Layer> The interface between the positive electrode active material layer and the solid electrolyte layer of the all-solid-state battery obtained by the above method was evaluated. The evaluation method is as follows. With the stacking direction of the positive electrode active material layer and the solid electrolyte layer set to the vertical direction, a cross section of the positive electrode active material layer and the solid electrolyte layer was photographed using a scanning electron microscope (SEM) at a magnification of 2000x so that the interface between the positive electrode active material layer and the solid electrolyte layer included 60 μm or more in the horizontal direction. The obtained cross-sectional SEM image was analyzed using Image J (National Institutes of Health) to measure the linear length L of the interface between the positive electrode active material layer and the solid electrolyte layer. ２Ａ and contact length L １Ａ The contact length L １Ａ is the length of the contact surface obtained by sampling the contact points between the positive electrode active material and the solid electrolyte in a 60 μm section in the horizontal direction in a cross-sectional SEM image and connecting each contact point with a straight line. ２Ａ The contact length L is the length of a straight line obtained by connecting two of the contact points sampled when measuring the contact length and projecting the line onto a horizontal plane. The value obtained by dividing the contact length by the length of the straight line is called the contact length L. １Ａ / Straight line length L ２Ａ The calculation results are shown in Table 1A as a ratio of the contact length to the straight line length. The ratio was calculated by measuring a total of nine locations shown in FIG. 2 , including the center in the planar direction of the interface between the positive electrode active material layer and the solid electrolyte layer, and using the average value of these measurements.

[0157] <Cycle Test> The cycle characteristics of the all-solid-state battery were evaluated by repeatedly charging and discharging the all-solid-state battery obtained by the above method. The charge and discharge conditions were as follows. Charge: constant current-constant voltage method, rate = 1 C, charge voltage 4.0 V, final current 0.01 C Discharge: constant current method, rate = 1 C Note that "C" is the symbol representing the current rate (time rate). At a rate of 1 C, the rated capacity of the battery is fully discharged in 1 hour. Note that in the above cycle test, the ratio of the discharge capacity after the second charge and discharge to the initial discharge capacity is called the capacity retention rate. Charging and discharging were repeated under the above charge and discharge conditions, and the capacity retention rate after 100 charge and discharge tests, i.e., at the 100th cycle, was determined and designated as the "capacity retention rate at 1 C." The results are shown in Table 1A.

[0158]

[0159] The raw materials for the all-solid-state batteries of Examples 1A to 2A and Comparative Example 1A are as follows: <Positive electrode> Positive electrode active material: LiNi ０．８ Co ０．１ Mn ０．１ O ２ (Average particle diameter d ５０ : 5 μm), content in positive electrode active material layer: 76 mass% Solid electrolyte: Li ６ P.S. ５ Cl (average particle diameter d ５０ : 6.5 μm), content in positive electrode active material layer: 19.5 mass% Conductive additive: CB (carbon black), content in positive electrode active material layer: 1.5 mass% Binder resin: SBR (styrene-butadiene rubber), content in positive electrode active material layer: 3 mass%

[0160] <Solid electrolyte layer> - Solid electrolyte: Li ６ P.S. ５ Cl (average particle diameter d ５０ Binder resin: SBR (styrene-butadiene rubber), content in solid electrolyte layer: 5% by mass

[0161] The second embodiment of the present invention will be specifically described below using examples, but the present invention is not limited to these examples.

[0162] <<Examples 1B to 8B and Comparative Examples 1B to 3B>> The second embodiment of the present invention will be described in detail below with reference to Examples 1B to 8B and Comparative Examples 1B to 3B. Note that the second embodiment is not limited to the descriptions of these examples.

[0163] All-solid-state batteries according to Examples 1B to 8B and Comparative Examples 1B to 3B were fabricated by the following method.

[0164] [I] Preparation of a Negative Electrode-Solid Electrolyte Layer Laminate (1) A foil was prepared as a negative electrode, with a 20 μm-thick negative electrode active material layer formed on the surface of a 10 μm-thick stainless steel negative electrode current collector. The anode materials used for the negative electrode active material layer in each Example and Comparative Example are shown in Table 1B. (2) A slurry in which a solid electrolyte and a binder resin were dispersed in xylene was applied to the surface of a polyester film primarily composed of polyester, and then dried to form a solid electrolyte layer on the polyester film. In Example 3B, Comparative Example 1B, and Comparative Example 2B, the solid electrolyte layer was formed on the polyester film by pressing under a pressure of 300 MPa for 1 minute using a cold isostatic pressing apparatus. Next, the solid electrolyte layer was laminated on the negative electrode together with the polyester film so that the resulting solid electrolyte layer was in contact with the surface of the negative electrode active material layer of the negative electrode, thereby obtaining a negative electrode-solid electrolyte layer laminate. (3) The anode-solid electrolyte layer laminate obtained in (2) above was vacuum-sealed using a vacuum laminator and held at room temperature (25°C) for 30 seconds to 1 minute. The anode-solid electrolyte layer laminate was then removed from the vacuum laminator and compressed by isostatic pressing (CIP) at room temperature (25°C) under a pressure of 300 MPa for 1 minute to obtain an anode-solid electrolyte layer laminate. The size of the anode-solid electrolyte layer laminate was 26 mm x 26 mm. (4) The polyester film was peeled off from the solid electrolyte layer to obtain an anode-solid electrolyte layer laminate.

[0165] [II] Lamination of Positive Electrode and Negative Electrolyte Layer Laminate (1) A positive electrode active material, a solid electrolyte, a conductive additive, and a binder resin were dispersed in butyl butyrate to obtain a slurry. The obtained slurry was then applied to a 10 μm thick aluminum foil and dried to form a positive electrode active material layer. A positive electrode was then obtained by hot roll pressing under conditions of 80°C and 5000 kg / cm. (2) The positive electrode obtained in (1) above was cut into a 20 mm x 20 mm size, and the positive electrode and the negative electrode-solid electrolyte layer laminate were laminated such that the positive electrode active material layer was in contact with the solid electrolyte layer of the negative electrode-solid electrolyte layer laminate prepared in [I] above, thereby obtaining an electrode laminate precursor. The number of layers of the positive electrode and the negative electrode-solid electrolyte layer laminate was one each.

[0166] [III] Preparation of Electrode Laminate The electrode laminate precursor obtained in [II] above was vacuum sealed using a vacuum laminator and held for 1 minute. Next, the electrode laminate precursor was removed from the vacuum laminator and compressed for 1 minute by a CIP method at room temperature (25°C) while applying a pressure at the "press pressure during cell production" value shown in Table 1B to obtain an electrode laminate.

[0167] [IV] Encapsulation in an exterior body The electrode laminate obtained in [III] above was enclosed in an aluminum exterior body (manufactured by Dai Nippon Printing Co., Ltd.) by the method described in the second embodiment, and an all-solid-state battery in which the positive electrode terminal and the negative electrode terminal were extended to the outside of the exterior body was obtained.

[0168] <Evaluation of the interface between the negative electrode active material layer and the solid electrolyte layer> The all-solid-state battery obtained by the above method was subjected to evaluation of the interface between the negative electrode active material layer and the solid electrolyte layer. The evaluation method is as follows. With the direction in which the negative electrode active material layer and the solid electrolyte layer were stacked vertically, a cross section of the negative electrode active material layer and the solid electrolyte layer was photographed using a scanning electron microscope (SEM) at a magnification of 2000x so that the interface between the negative electrode active material layer and the solid electrolyte layer included 60 μm or more in the horizontal direction. The obtained cross-sectional SEM image was analyzed using Image J (manufactured by the National Institutes of Health) to measure the linear length L of the interface between the negative electrode active material layer and the solid electrolyte layer. ２Ｂ and contact length L １Ｂ The contact length L１Ｂ is the length of the contact surface obtained by sampling the contact points between the negative electrode active material layer and the solid electrolyte in a 60 μm section in the horizontal direction in a cross-sectional SEM image and connecting each contact point with a straight line. ２Ｂ The contact length is the length of a straight line obtained by connecting two of the contact points sampled when measuring the contact length and projecting the line onto a horizontal plane. The value obtained by dividing the contact length by the straight line length is called the contact length / straight line length ratio (L １Ｂ / L ２Ｂ The calculation results are shown in Table 1B. The ratio of contact length to linear length was determined by measuring a total of nine locations shown in FIG. 2 , including the center in the planar direction of the interface between the negative electrode active material layer and the solid electrolyte layer, and the average value of these measurements was used.

[0169] <High-Rate Discharge Characteristics Test> The high-rate discharge characteristics of the all-solid-state battery were evaluated by charging and discharging the all-solid-state battery obtained by the above method under the following conditions. The charge and discharge conditions were as follows: Charge: constant current-constant voltage method, rate = 0.1 C, charge voltage 4.0 V, final current 0.01 C Discharge: constant current method, rate = 0.1 C, 1 C, 2 C, 3 C Note that "C" is the symbol representing the current rate (time rate). At a rate of 1 C, the rated capacity of the battery is fully discharged in 1 hour. The ratio of the discharge capacity when discharged at each rate (1 C, 2 C, 3 C) to the discharge capacity when discharged at 0.1 C was calculated. The obtained results are shown in Table 1B. Note that in Comparative Example 1B, the negative electrode active material layer and the solid electrolyte layer were not in close contact with each other, so an all-solid-state battery could not be produced.

[0170]

[0171] The raw materials for the all-solid-state batteries of Examples 1B to 8B and Comparative Examples 1B to 3B are as follows: <Positive electrode> Positive electrode active material: LiNi ０．８ Co ０．１ Mn ０．１ O ２ (Average particle diameter d ５０ : 1.5 μm), content in positive electrode active material layer: 76 mass% Solid electrolyte: Li ６ P.S. ５ Cl (average particle diameter d ５０: 6.5 μm), content in positive electrode active material layer: 19.5 mass% Conductive additive: CB (carbon black), content in positive electrode active material layer: 1.5 mass% Binder resin: SBR (styrene-butadiene rubber), content in positive electrode active material layer: 3 mass%

[0172] <Solid electrolyte layer> - Solid electrolyte: Li ６ P.S. ５ Cl (average particle diameter d ５０ Binder resin: SBR (styrene-butadiene rubber), content in solid electrolyte layer: 5% by mass

[0173] As described above, it was confirmed that the high-rate discharge characteristics of the all-solid-state batteries according to Examples 1B to 8B of the present invention were superior to those of Comparative Examples 1B to 3B. Furthermore, it was confirmed that the high-rate discharge characteristics were even superior in Examples 6B to 8B, in which a lithium-magnesium alloy was used as the anode material.

[0174] This application claims priority based on Japanese Patent Application No. 2024-054236 filed on March 28, 2024, and Japanese Patent Application No. 2025-041105 filed on March 14, 2025, the disclosures of which are incorporated herein in their entireties.

[0175] 1 Positive electrode active material layer 2 Negative electrode active material layer 3 Positive electrode current collector 4 Negative electrode current collector 5 Solid electrolyte layer 6 Exterior body 7 Exterior body 8 Negative electrode terminal 9 Positive electrode terminal 10 All-solid-state battery a １ ~a ９ area b １ and b ４ center line b ２ ~b ３ and b ５ ~b ６ straight line d １ ~d ４ Vertical distance between each line O Center α Interface between the positive electrode active material layer and the solid electrolyte layer, or interface between the negative electrode active material layer and the solid electrolyte layer

Claims

1. An all-solid-state battery comprising, in this order: a positive electrode including a positive electrode active material layer; a solid electrolyte layer including a solid electrolyte (A); and a negative electrode including a negative electrode active material layer, and satisfying at least one of the following requirements 1 and 2. Requirement 1: The positive electrode active material layer and the solid electrolyte layer are in contact with each other, and the contact length of the interface between the positive electrode active material layer and the solid electrolyte layer measured by the following method 1 is L １Ａ The straight line length is L ２Ａ When this is done, L １Ａ and L ２Ａ The ratio (L １Ａ / L ２Ａ ) is 1.1 or more and 1.4 or less (Method 1) A cross section of the cathode active material layer and the solid electrolyte layer is photographed using a scanning electron microscope (SEM) at a magnification of 2000 times, with the direction in which the cathode active material layer and the solid electrolyte layer are stacked being the vertical direction, so that the interface between the cathode active material layer and the solid electrolyte layer includes 60 μm or more in the horizontal direction. From the obtained cross-sectional SEM image, the linear length L of the interface between the cathode active material layer and the solid electrolyte layer is calculated using image analysis software. ２Ａ and contact length L １Ａ Measure the contact length L １Ａ is the length of the contact surface obtained by sampling the contact points between the positive electrode active material and the solid electrolyte in a 60 μm section in the horizontal direction in a cross-sectional SEM image and connecting each contact point with a straight line, and the straight line length L ２Ａ is the contact length L １Ａ Requirement 2: The negative electrode active material layer and the solid electrolyte layer are in contact with each other, and the contact length of the interface between the negative electrode active material layer and the solid electrolyte layer measured by the following method 2 is defined as L １Ｂ The straight line length is L ２Ｂ When this is done, L １Ｂ and L ２Ｂ The ratio (L １Ｂ / L ２Ｂ ) is 1.05 or more and 2.50 or less. (Method 2) A cross section of the negative electrode active material layer and the solid electrolyte layer is photographed using a scanning electron microscope (SEM) at a magnification of 2000 times, with the direction in which the negative electrode active material layer and the solid electrolyte layer are stacked being the vertical direction, so that the interface between the negative electrode active material layer and the solid electrolyte layer includes 60 μm or more in the horizontal direction. From the obtained cross-sectional SEM image, the linear length L of the interface between the negative electrode active material layer and the solid electrolyte layer is calculated using image analysis software. ２Ｂ and contact length L １Ｂ Measure the contact length L １Ｂ is the length of the contact surface obtained by sampling contact points between the negative electrode active material and the solid electrolyte in a 60 μm section in the horizontal direction in a cross-sectional SEM image and connecting each contact point with a straight line, and the straight line length L ２Ｂ is the contact length L １Ｂ When measuring the contact point, the two ends of the sampled contact points are connected by a straight line, and the length of the line obtained by projecting the line onto a horizontal plane is the length of the line.

2. The all-solid-state battery according to claim 1, which satisfies requirement 1.

3. The all-solid-state battery according to claim 2, wherein the positive electrode active material layer contains, as a positive electrode active material, a lithium composite oxide having a layered rock salt type crystal structure.

4. The all-solid-state battery according to claim 3, wherein the lithium composite oxide comprises one or more selected from the group consisting of lithium-nickel composite oxide, lithium-cobalt composite oxide, lithium-nickel-aluminum composite oxide, and lithium-nickel-cobalt-manganese composite oxide.

5. The all-solid-state battery according to claim 4, wherein the lithium composite oxide includes a lithium-nickel-cobalt-manganese composite oxide.

6. The all-solid-state battery according to any one of claims 2 to 5, wherein the negative electrode active material layer contains one or more negative electrode active materials selected from the group consisting of carbon materials, lithium-based metal materials, Si-based materials, and conductive polymer materials.

7. The all-solid-state battery according to claim 1, which satisfies requirement 2.

8. The all-solid-state battery according to claim 7, wherein the negative electrode active material layer includes a lithium layer on a surface in contact with the solid electrolyte layer.

9. The all-solid-state battery according to claim 7, wherein the negative electrode active material layer includes a layer formed of an alloy containing lithium and magnesium on a surface in contact with the solid electrolyte layer.

10. L １Ｂ and L ２Ｂ The ratio (L １Ｂ / L ２Ｂ 10. The all-solid-state battery according to claim 7, wherein the σ is 1.20 or more and 2.50 or less.

11. The all-solid-state battery according to any one of claims 1 to 10, wherein the solid electrolyte (A) comprises one or more selected from the group consisting of sulfide-based solid electrolytes, oxide-based solid electrolytes, and polymer-based solid electrolytes.

12. The all-solid-state battery according to any one of claims 1 to 11, wherein the content of the solid electrolyte (A) in the solid electrolyte layer is 50.0 parts by mass or more and 100.0 parts by mass or less, when the entire solid electrolyte layer is taken as 100.0 parts by mass.

13. A battery module comprising the all-solid-state battery according to any one of claims 1 to 12.

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