Manufacturing method for all-solid battery, and manufacturing apparatus for all-solid battery

Abstract

To provide a manufacturing method for an all-solid battery capable of achieving thinning and uniformity of a powder film, and a manufacturing apparatus for the all-solid battery.SOLUTION: A manufacturing method for an all-solid battery 1 includes: a granulating step of forming a first grain body by aggregating a powder body material; a pulverizing step of forming a second grain body that is smaller than the first grain body by pulverizing the first grain body; an electrode multilayer body forming step of forming an electrode multilayer body 2 by depositing the second grain body on a first base material F1 in a dry procedure; and a stacking step of stacking the electrode multilayer body 2 and a current collector 3.SELECTED DRAWING: Figure 8

Description

Technical Field

[0001] The present invention relates to a method for manufacturing an all-solid-state battery and a manufacturing apparatus for an all-solid-state battery.

Background Art

[0002] Conventionally, a method of forming a powder film (positive electrode layer, negative electrode layer, solid electrolyte layer) of an all-solid-state secondary battery using an electrostatic film-forming apparatus has been known (see Patent Document 1 below).

[0003] The positive electrode layer is formed from a mixture of a powder of a positive electrode active material and a powder of a solid electrolyte. The solid electrolyte layer is formed from a powder of a solid electrolyte. The negative electrode layer is formed from a mixture of a powder of a negative electrode active material and a powder of a solid electrolyte.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In general, the smaller the particle size of a powder, the lower its fluidity and the more difficult it is to handle (poor handling property). Therefore, although granulation is desired as a means to improve fluidity, there is a problem that the particle size usually becomes too large and thus it cannot be used as a powder for forming a thin film.

[0006] Further, in the method described in Patent Document 1 above, when the fluidity of the powder is low, it is difficult to make the powder film thinner and to make the thickness of the powder film uniform.

[0007] The present invention provides a method for manufacturing an all-solid-state battery and a manufacturing system for an all-solid-state battery, which can more easily make the powder film thinner and make the thickness of the powder film uniform.

Means for Solving the Problems

[0008] The present invention [1] includes a granulation step of aggregating a powder material to form first granules, a pulverization step of crushing the first granules to form second granules smaller than the first granules, an electrode laminate forming step of depositing the second granules on a substrate to form an electrode laminate, and a lamination step of laminating the electrode laminate and a current collector, and includes a method for manufacturing an all-solid-state battery.

[0009] According to such a method, in the granulation step, after aggregating the powder material to form first granules, in the pulverization step, the first granules are crushed to form second granules smaller than the first granules.

[0010] Therefore, by aggregating the powder material, the fluidity can be improved.

[0011] Furthermore, by crushing the first granules, it is possible to suppress the situation where coarse granules hinder the thinning of the powder film.

[0012] As a result, it is possible to achieve thinning of the powder film and uniformization of the thickness of the powder film.

[0013] The present invention [2] includes the method for manufacturing an all-solid-state battery according to [1] above, wherein the granulation step and the pulverization step are performed dry.

[0014] According to such a method, when forming a powder film dry using a powder material with low fluidity, it is possible to achieve thinning of the powder film and uniformization of the thickness of the powder film.

[0015] The present invention [3] includes the method for manufacturing an all-solid-state battery according to [1] or [2] above, wherein the median diameter (d50) of the powder material measured by the laser diffraction / scattering method is less than 10 μm on a number basis.

[0016] According to such a method, it is possible to reduce the thickness of the powder film and make the thickness of the powder film uniform by using a powder material having a median diameter of less than 10 μm and low fluidity.

[0017] The present invention [4] includes a method for manufacturing an all-solid-state battery according to any one of [1] to [3] above, wherein the median diameter (d50) of the second particles measured by the laser diffraction / scattering method is 30 μm or less on a number basis.

[0018] According to such a configuration, since the median diameter of the second particles is less than 30 μm, it is possible to suppress the coarse particles from hindering the thinning of the powder film.

[0019] The present invention [5] includes a method for manufacturing an all-solid-state battery according to any one of [1] to [4] above, wherein in the pulverization step, the first particles are attrited.

[0020] According to such a method, the particle diameter of the second particles can be made uniform, and the shape of the second particles can be made closer to a spherical shape.

[0021] The present invention [6] includes a method for manufacturing an all-solid-state battery according to any one of [1] to [5] above, further including a removal step of removing fine powder at least at one timing after the granulation step, before the pulverization step, and after the pulverization step and before the electrode laminate formation step.

[0022] According to such a method, by removing the fine powder, the fluidity of the second particles can be further improved.

[0023] The present invention [7] includes a method for manufacturing an all-solid-state battery according to any one of [1] to [6] above, wherein the powder material is a powder containing a solid electrolyte.

[0024] According to such a method, it is possible to reduce the thickness and make the thickness uniform for at least one of the positive electrode layer, the negative electrode layer, and the solid electrolyte layer.

[0025] The present invention [8] includes a granulation unit that aggregates a powder material to form first granules, a pulverization unit that pulverizes the first granules to form second granules smaller than the first granules, an electrode laminate forming unit that deposits the second granules on a substrate to form an electrode laminate, and a lamination unit that laminates the electrode laminate and a current collector.

[0026] According to such a configuration, in the granulation unit, after aggregating the powder material to form first granules, in the pulverization unit, the first granules are pulverized to form second granules smaller than the first granules.

[0027] Therefore, in the granulation unit, the powder material can be aggregated to improve fluidity.

[0028] Furthermore, in the pulverization unit, by pulverizing the first granules, it is possible to suppress the coarse granules from hindering the thinning of the powder film.

[0029] As a result, it is possible to thin the powder film and make the thickness of the powder film uniform.

[0030] The present invention [9] includes the granulation unit provided with a granulation device that forms the first granules, the pulverization unit provided with a pulverization device that grinds the first granules, and at least one of the granulation unit and the pulverization unit further includes a removal device that removes fine powder, and includes the manufacturing system of the all-solid-state battery of the above [8].

[0031] According to such a configuration, by removing fine powder, the fluidity of the second granules can be further improved.

Effects of the Invention

[0032] According to the manufacturing method of the all-solid-state battery and the manufacturing system of the all-solid-state battery of the present invention, it is possible to thin the powder film and make the thickness of the powder film uniform.

Brief Description of the Drawings

[0033]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

DETAILED DESCRIPTION OF THE INVENTION

[0034] 1. All-Solid-State Battery The all-solid-state battery 1 will be described.

[0035] As shown in FIGS. 1A and 1B, the all-solid-state battery 1 includes a plurality of electrode laminates 2, a plurality of current collectors 3, a positive electrode lead 4, a negative electrode lead 5, and an exterior member 6.

[0036] (1) Electrode laminate In this embodiment, the electrode laminate 2 has a sheet shape. The electrode laminate 2 is substantially rectangular when viewed from the thickness direction of the electrode laminate 2. Note that the shape of the electrode laminate 2 is not limited. The electrode laminate 2 may be in a plate shape or a film shape. Also, the electrode laminate 2 may be substantially circular when viewed from the thickness direction of the electrode laminate 2.

[0037] The thickness of the electrode laminate 2 is, for example, 100 μm or more, preferably 200 μm or more, and, for example, 1000 μm or less, preferably 800 μm or less.

[0038] As shown in FIG. 2A, the electrode laminate 2 includes a positive electrode layer 21, a negative electrode layer 22, and a solid electrolyte layer 23. The electrode laminate 2 is composed of the positive electrode layer 21, the negative electrode layer 22, and the solid electrolyte layer 23. The electrode laminate 2 does not have a current collector.

[0039] (1-1) Positive electrode layer The positive electrode layer 21 is disposed away from the negative electrode layer 22 in the thickness direction of the electrode laminate 2. The positive electrode layer 21 is disposed on the opposite side of the negative electrode layer 22 with respect to the solid electrolyte layer 23 in the thickness direction of the electrode laminate 2. The positive electrode layer 21 is in contact with the solid electrolyte layer 23 and not in contact with the negative electrode layer 22.

[0040] The positive electrode layer 21 is made from a powder containing a positive electrode active material. In this embodiment, the positive electrode layer 21 does not contain a resin such as a binder. In this embodiment, the positive electrode layer 21 is made from a mixture (positive electrode composite material) of a powder of the positive electrode active material and a powder of the solid electrolyte. Note that the positive electrode layer 21 may not contain a solid electrolyte. The positive electrode layer 21 may consist of only the positive electrode active material.

[0041] Examples of the positive electrode active material include lithium-containing oxides. Examples of the lithium-containing oxides include lithium-nickel composite oxides (LiNi X M 1-X O2), lithium cobalt oxide (LiCoO2), lithium nickel oxide (LiNiO2), lithium-nickel-cobalt-aluminum composite oxides (LiNi0.8 Co 0.15 Al 0.05 O2, NCA-based layered oxides), lithium manganate (spinel-type lithium manganate (LiMn2O4)), and Li-excess composite oxides (Li2MnO3-LiMO2).

[0042] The cathode active material is not limited to lithium-containing oxides as long as insertion and extraction of lithium ions are possible. Examples of the cathode active material include olivine-based compounds (LiMPO4) and sulfur-containing compounds (Li2S).

[0043] In the above chemical formula, M represents a transition metal.

[0044] From the viewpoint of easily obtaining a high capacity, the cathode active material preferably includes a lithium-containing oxide containing at least one selected from the group consisting of Co, Ni, and Mn.

[0045] Also, from the viewpoint of improving rate characteristics, the surface of the cathode active material may be coated with a coating material.

[0046] Examples of the coating material include Li4Ti5O 12 , LiTaO3, Li4NbO3, LiAlO2, Li2ZrO3, Li2WO4, Li2TiO3, Li2B4O7, Li3PO4, Li2MoO4, LiBO2, alumina (Al2O3), and carbon (C).

[0047] The cathode active material can be used alone or in combination of two or more.

[0048] The solid electrolyte exhibits lithium ion conductivity. Examples of the solid electrolyte include organic solid electrolytes and inorganic solid electrolytes.

[0049] Examples of the inorganic solid electrolyte include sulfides, oxides, nitrides, and hydrides.

[0050] Examples of the sulfide include those containing Li2S and other sulfides containing at least one element selected from the group consisting of Group 13 elements, Group 14 elements, and Group 15 elements of the periodic table.

[0051] Examples of the Group 13 elements, Group 14 elements, and Group 15 elements of the periodic table include P, Si, Ge, As, Sb, and Al. Preferably, P, Si, and Ge are included. More preferably, P is included.

[0052] Specifically, examples of the sulfide include Li2S - SiS2, Li2S - P2S5, Li2S - GeS2, Li2S - B2S3, Li2S - Ga2S3, Li2S - Al2S3, Li2S - GeS2 - P2S5, Li2S - Al2S3 - P2S5, Li2S - P2S3, Li2S - P2S3 - P2S5, LiX - Li2S - P2S5, LiX - Li2S - SiS2, and LiX - Li2S - B2S3 (X: I, Br, or Cl).

[0053] Preferably, the solid electrolyte is an inorganic solid electrolyte, and more preferably, it is a sulfide. The solid electrolyte can be used alone or in combination of two or more. The ratio of the positive electrode active material to the solid electrolyte is not limited. The powder of the solid electrolyte in the positive electrode layer 21 may contain the first granule and the second granule described later. By using the second granule described later as the powder of the solid electrolyte in the positive electrode layer 21, it is possible to reduce the thickness of the powder film and make the thickness of the powder film uniform.

[0054] The thickness of the positive electrode layer 21 is, for example, 50 μm or more, preferably 100 μm or more. The thickness of the positive electrode layer 21 is, for example, 500 μm or less, preferably 300 μm or less.

[0055] (1 - 2) Negative electrode layer The negative electrode layer 22 is arranged away from the positive electrode layer 21 in the thickness direction of the electrode laminate 2. The negative electrode layer 22 is arranged on the opposite side of the positive electrode layer 21 with respect to the solid electrolyte layer 23 in the thickness direction of the electrode laminate 2. The negative electrode layer 22 is in contact with the solid electrolyte layer 23 and not in contact with the positive electrode layer 21.

[0056] The negative electrode layer 22 is made from a powder containing a negative electrode active material. In the present embodiment, the negative electrode layer 22 does not contain a resin such as a binder. In the present embodiment, the negative electrode layer 22 is made from a mixture (negative electrode composite material) of a powder of a negative electrode active material and a powder of a solid electrolyte. Note that the negative electrode layer 22 may not contain a solid electrolyte. The negative electrode layer 22 may consist only of a negative electrode active material.

[0057] The negative electrode active material is not limited as long as it is a material capable of inserting and extracting lithium ions. Examples of the negative electrode active material include carbon materials, metals and their alloys, semimetals, and compounds of metals or semimetals.

[0058] Examples of the carbon material include graphite (natural graphite, artificial graphite), hard carbon, and amorphous carbon. Examples of the metal and its alloy include lithium and its alloy. An example of the semimetal is silicon. Examples of the compound of a metal or a semimetal include oxides, sulfides, nitrides, hydrides, and silicides (lithium silicide) of a metal or a semimetal. Examples of the oxide of a metal or a semimetal include titanium oxide and silicon oxide.

[0059] The negative electrode active material can be used alone or in combination of two or more. For example, silicon oxide and a carbon material can be used in combination as the negative electrode active material.

[0060] Examples of the solid electrolyte contained in the negative electrode layer 22 include the solid electrolytes described above. Preferably, the solid electrolyte contained in the negative electrode layer 22 is the same as the solid electrolyte contained in the positive electrode layer 21. The ratio of the negative electrode active material to the solid electrolyte is not limited. The powder of the solid electrolyte in the negative electrode layer 22 may contain a first granule and a second granule, which will be described later. By using the second granule, which will be described later, as the powder of the solid electrolyte in the negative electrode layer 22, it is possible to reduce the thickness of the powder film and make the thickness of the powder film uniform.

[0061] The thickness of the negative electrode layer 22 is approximately the same as that of the positive electrode layer 21. The thickness of the negative electrode layer 22 is, for example, 50 μm or more, preferably 100 μm or more. The thickness of the negative electrode layer 22 is, for example, 500 μm or less, preferably 300 μm or less.

[0062] (1-3) Solid electrolyte layer The solid electrolyte layer 23 is disposed between the positive electrode layer 21 and the negative electrode layer 22 in the thickness direction of the electrode laminate 2. The solid electrolyte layer 23 is made from a powder of the solid electrolyte. In the present embodiment, the solid electrolyte layer 23 does not contain a resin such as a binder.

[0063] Examples of the solid electrolyte include the solid electrolytes described above. Preferably, the solid electrolyte is the same as the solid electrolyte contained in the positive electrode layer 21. The powder of the solid electrolyte of the solid electrolyte layer 23 may contain a first granule and a second granule, which will be described later. By using the second granule, which will be described later, as the powder of the solid electrolyte of the solid electrolyte layer 23, it is possible to reduce the thickness of the powder film and make the thickness of the powder film uniform.

[0064] The solid electrolyte layer 23 is thinner than the positive electrode layer 21 and the negative electrode layer 22. The thickness of the solid electrolyte layer 23 is, for example, 10 μm or more, preferably 30 μm or more. The thickness of the solid electrolyte layer 23 is, for example, 300 μm or less, preferably 100 μm or less.

[0065] (2) Current collector As shown in FIG. 2B, in the present embodiment, in the case of parallel connection, each of the plurality of current collectors 3 is alternately laminated with each of the plurality of electrode laminates 2. The plurality of current collectors 3 includes a positive electrode current collector 3A and a negative electrode current collector 3B. The positive electrode current collector 3A is in contact with the positive electrode layer 21 of the electrode laminate 2. The negative electrode current collector 3B is in contact with the negative electrode layer 22 of the electrode laminate 2.

[0066] Specifically, in the present embodiment, in the stacking direction of the electrode laminate 2 and the current collector 3, the positive current collector 3A, the first electrode laminate 2A, the negative current collector 3B, the second electrode laminate 2B, and the positive current collector 3A are stacked in this order from one side to the other side. In the stacking direction, one negative current collector 3B is disposed between the negative electrode layer 22 of the first electrode laminate 2A and the negative electrode layer 22 of the second electrode laminate 2B. That is, in the stacking direction, one current collector 3 is disposed between two electrode laminates 2.

[0067] In the case of series connection, a plurality of electrode laminates 2 are stacked such that the stacking order of the positive electrode layer 21, the solid electrolyte layer 23, and the negative electrode layer 22 is the same, and the current collectors 3 are disposed only on the uppermost layer and the lowermost layer.

[0068] As shown in FIGS. 3A and 3B, the current collector 3 includes a conductor 31, an insulating member 32, and an adhesive layer 33.

[0069] (2-1) Conductor The conductor 31 is made of, for example, a metal. The conductor 31 has a stacked portion 311 and a tab 312.

[0070] The stacked portion 311 extends in a first direction and a second direction. The first direction is orthogonal to the stacking direction. The second direction is orthogonal to both the first direction and the stacking direction. The stacked portion 311 has a sheet shape. The stacked portion 311 has one surface S1 and the other surface S2 in the thickness direction. In other words, the conductor 31 has one surface S1 and the other surface S2 in the thickness direction. The stacked portion 311 is in contact with the electrode laminate 2. When the current collector 3 is the positive current collector 3A, the stacked portion 311 is in contact with the positive electrode layer 21 of the electrode laminate 2. When the current collector 3 is the negative current collector 3B, the stacked portion 311 is in contact with the negative electrode layer 22 of the electrode laminate 2.

[0071] The tab 312 is disposed at the edge of the stacked portion 311. In the present embodiment, the tab 312 is disposed at one edge of the stacked portion 311 in the second direction. The tab 312 protrudes from the edge of the stacked portion 311. The tab 312 is a member separate from the stacked portion 311 and may be joined to the stacked portion 311. The tab 312 does not contact the electrode laminate 2. When the current collector 3 is the positive current collector 3A, the conductor 31 has a positive tab 312A as the tab 312. When the current collector 3 is the negative current collector 3B, the conductor 31 has a negative tab 312B as the tab 312. In a state where the electrode laminate 2, the positive current collector 3A, and the negative current collector 3B are stacked, the negative tab 312B is disposed away from the positive tab 312A. In a state where the electrode laminate 2, the positive current collector 3A, and the negative current collector 3B are stacked, in the stacking direction, the negative tab 312B does not overlap the positive tab 312A.

[0072] The thickness of the conductor 31 is, for example, 1 μm or more, preferably 5 μm or more, and, for example, 100 μm or less, preferably 50 μm or less.

[0073] Examples of the material of the conductor 31 include copper (Cu), magnesium (Mg), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), nickel (Ni), zinc (Zn), aluminum (Al), germanium (Ge), indium (In), lithium (Li), tin (Sn), and alloys thereof.

[0074] (2-2) Insulating member In the present embodiment, as shown in FIG. 3B, the insulating member 32 is stacked on one surface S1 of the conductor 31. As shown in FIG. 3A, the insulating member 32 is disposed on the stacked portion 311 of the conductor 31. The insulating member 32 is stacked on the peripheral edge of the stacked portion 311 of the conductor 31. The insulating member 32 has a substantially rectangular frame shape when viewed from the stacking direction. The insulating member 32 is not disposed on the tab 312 of the conductor 31.

[0075] In a state where the electrode laminate 2, the positive electrode current collector 3A, and the negative electrode current collector 3B are laminated, the insulating member 32 is disposed around the electrode laminate 2. As shown in FIG. 1B, in a state where the electrode laminate 2, the positive electrode current collector 3A, and the negative electrode current collector 3B are laminated, the insulating member 32 is disposed between the positive electrode current collector 3A and the negative electrode current collector 3B in the lamination direction. In a state where the electrode laminate 2, the positive electrode current collector 3A, and the negative electrode current collector 3B are laminated, the insulating member 32 insulates the positive electrode current collector 3A from the negative electrode current collector 3B.

[0076] In the lamination direction, the thickness of the insulating member 32 is thinner than the thickness of the electrode laminate 2. When the current collector 3 does not have the adhesive layer 33, the thickness of the insulating member 32 may be the same as the thickness of the electrode laminate 2. The thickness of the insulating member 32 is, for example, 50 μm or more, preferably 75 μm or more, and, for example, 500 μm or less, preferably 400 μm or less.

[0077] Examples of the material of the insulating member 32 include polyethylene terephthalate and polyimide.

[0078] (2-3) Adhesive layer As shown in FIG. 3B, the adhesive layer 33 is laminated on the other surface S2 of the conductor 31 at the peripheral edge of the conductor 31. The current collector 3 may not have the adhesive layer 33. As shown in FIG. 1B, in a state where one electrode laminate 2 is laminated between two current collectors 3, the adhesive layer 33 of the current collector 3 disposed on the other side of the electrode laminate 2 in the lamination direction is adhered to the insulating member 32 of the current collector 3 disposed on one side of the electrode laminate 2 in the lamination direction.

[0079] The sum of the thickness of the adhesive layer 33 and the thickness of the insulating member 32 is equal to or less than the thickness of the electrode laminate 2. The thickness of the adhesive layer 33 is, for example, 30 μm or more, preferably 50 μm or more, and, for example, 300 μm or less, preferably 200 μm or less.

[0080] Next, the adhesive layer 33 is preferably insulating. Examples of the material of the adhesive layer 33 include resins such as acrylic, polyimide, and silicone, and non-woven fabrics impregnated with these resins.

[0081] (3) Positive electrode lead and negative electrode lead As shown in FIG. 1A, a part of the positive electrode lead 4 is exposed from the exterior material 6. As shown in FIG. 4, the positive electrode lead 4 is joined to the positive electrode tab 312A within the exterior material 6. Thereby, the positive electrode lead 4 is electrically connected to the positive electrode current collector 3A. The positive electrode lead 4 is not connected to the negative electrode current collector 3B.

[0082] As shown in FIG. 1A, a part of the negative electrode lead 5 is exposed from the exterior material 6. The negative electrode lead 5 is joined to the negative electrode tab 312B (see FIG. 3A) within the exterior material 6. Thereby, the negative electrode lead 5 is electrically connected to the negative electrode current collector 3B (see FIG. 1B). The negative electrode lead 5 is not connected to the positive electrode current collector 3A.

[0083] Each of the positive electrode lead 4 and the negative electrode lead 5 has, for example, a substantially rectangular flat plate shape. Examples of the material of the positive electrode lead 4 and the negative electrode lead 5 include pure metals and alloys. Examples of the pure metal include copper, nickel, aluminum, gold, and platinum. Examples of the alloy include alloys of the above pure metals, stainless steel, and titanium. The positive electrode lead 4 and the negative electrode lead 5 may be plated. For example, the positive electrode lead 4 and the negative electrode lead 5 may be copper plates having a nickel plating layer and a gold plating layer.

[0084] (4) Exterior material As shown in FIGS. 1A and 1B, the exterior material 6 covers the laminate of the electrode laminate 2 and the current collector 3. Examples of the exterior material 6 include a metal laminate film in which resin films are laminated on both sides of a metal foil.

[0085] 2. Manufacturing method of all-solid-state battery Next, a method for manufacturing the above-described all-solid-state battery 1 will be described.

[0086] The manufacturing method of the all-solid-state battery 1 of this embodiment includes a raw material preparation process (see FIG. 5), an electrode laminate formation process (see FIGS. 6A to 7A), a pressing process (see FIG. 7B), a cutting process, a peeling process (see FIG. 7C), and a lamination process.

[0087] (1) Raw material preparation process In the raw material preparation process, the solid electrolyte granule, the positive electrode composite material, and the negative electrode composite material are prepared.

[0088] As shown in FIG. 5, the raw material preparation process includes a granulation process, a pulverization process, and a removal process. Further, the raw material preparation process includes a mixing process. In other words, the manufacturing method of the all-solid-state battery 1 includes a granulation process, a pulverization process, a removal process, and a mixing process.

[0089] (1-1) Granulation process In the raw material preparation process, first, the granulation process is carried out.

[0090] In the granulation process, the powder of the solid electrolyte (an example of the powder material) is aggregated to form the first granule. The granulation process is carried out dry. Examples of the granulation method that can be adopted in the granulation process include rolling, vibration, and stirring. Preferably, rolling is mentioned as the granulation method.

[0091] The median diameter (d50) of the powder of the solid electrolyte is, for example, less than 10 μm, preferably 5 μm or less, based on the number standard. The median diameter (d50) of the powder material is, for example, 0.01 μm or more, preferably 0.05 μm or more, based on the number standard.

[0092] When the median diameter (d50) of the powder of the solid electrolyte is less than the above upper limit value, the cohesive force between particles is strong. Therefore, when the median diameter (d50) of the powder of the solid electrolyte is less than the above upper limit value, the fluidity of the powder of the solid electrolyte tends to be low.

[0093] When the median diameter (d50) of the solid electrolyte powder is less than the above upper limit value, intermolecular forces such as van der Waals forces increase, so the chance of powder particles contacting each other increases, and dry aggregation (granulation) can be expected.

[0094] When the median diameter (d50) of the solid electrolyte powder is greater than or equal to the above lower limit value, the powder can be made to flow to some extent, so dry aggregation (granulation) can be expected by processes such as rolling.

[0095] The median diameter (d50) is measured by the laser diffraction / scattering method.

[0096] The first granule is an aggregate of the solid electrolyte powder. The first granule is larger than the solid electrolyte powder.

[0097] The median diameter (d50) of the first granule is, on a number basis, for example, 10 μm or more, preferably 20 μm or more. The median diameter (d50) of the first granule is, on a number basis, for example, 100 μm or less, preferably 80 μm or less.

[0098] When the median diameter (d50) of the first granule is greater than or equal to the above lower limit value, gravity acts on the powder more than intermolecular forces such as van der Waals forces, and the fluidity improves, so it can be expected that the treatment in the pulverization process will be good.

[0099] When the median diameter (d50) of the first granule is less than or equal to the above upper limit value, second granules suitable for the thickness of the powder layer required for the all-solid-state battery can be obtained.

[0100] (1-2) Pulverization process Next, in the raw material preparation process, a pulverization process is carried out.

[0101] In the pulverization process, the first particles are pulverized to form the second particles. The pulverization process is carried out dry. Examples of the pulverization method that can be adopted in the pulverization process include grinding. Preferably, in the pulverization process, the first particles are ground. By grinding, the particle size of the second particles can be made uniform, and the shape of the second particles can be made closer to spherical.

[0102] The second particles are smaller than the first particles. The second particles are larger than the powder of the solid electrolyte. The median diameter (d50) of the second particles is, on a number basis, for example, 30 μm or less, preferably 20 μm or less. The median diameter (d50) of the second particles measured by the laser diffraction / scattering method is, on a number basis, for example, 5 μm or more, preferably 10 μm or more.

[0103] When the median diameter (d50) of the second particles is equal to or less than the above upper limit value, in the electrode laminate forming process, the solid electrolyte layer can be made thinner.

[0104] When the median diameter (d50) of the second particles is equal to or greater than the above lower limit value, the fluidity of the second particles can be sufficiently improved compared to the fluidity of the powder of the solid electrolyte.

[0105] (1-3) Removal process The removal process is carried out, if necessary, at the timing after the pulverization process and before the electrode laminate forming process.

[0106] In the removal process, for example, fine powder is removed by air power. By removing the fine powder, the fluidity of the second particles can be further improved.

[0107] The fine powder is smaller than the second particles. The fine powder may be independent of the second particles or may adhere to the surface of the second particles.

[0108] The median diameter (d50) of the fine powder is, on a number basis, for example, 1 μm or less, preferably 3 μm or less.

[0109] Note that the removal process may be performed at the timing after the granulation process and before the pulverization process. Further, the removal process may be performed at both timings after the granulation process and before the pulverization process, and after the pulverization process and before the electrode laminate formation process.

[0110] (1-4) Mixing process In the mixing process, a positive electrode composite material and a negative electrode composite material are prepared. In the mixing process, when preparing the positive electrode composite material, the powder of the solid electrolyte and the powder of the positive electrode active material are mixed. When preparing the negative electrode composite material, the powder of the solid electrolyte and the powder of the negative electrode active material are mixed. By the mixing process, a positive electrode composite material and a negative electrode composite material are obtained.

[0111] (2) Electrode laminate formation process In the electrode laminate formation process, the electrode laminate 2 is formed dry on the first base material F1. Specifically, for example, the electrode laminate 2 is formed on the first base material F1 by electrostatic screen printing.

[0112] As shown in FIG. 6A, the positive electrode composite material M1 is filled into the opening OP of the screen SC having a predetermined volume.

[0113] Next, as shown in FIG. 6B, the positive electrode composite material M1 in the opening OP is extruded toward the first base material F1 and transferred onto the first base material F1 by electrostatic force. Thereby, the positive electrode layer 21 is formed on the first base material F1.

[0114] Next, the solid electrolyte layer 23 is formed on the positive electrode layer 21 in the same manner as the formation of the positive electrode layer 21.

[0115] Specifically, the second granule is filled into the opening OP of the screen SC. Next, the second granule in the opening OP is extruded toward the first base material F1 and transferred onto the first base material F1 by electrostatic force. That is, in the electrode laminate formation process, the second granule is deposited dry on the first base material F1. Thereby, the solid electrolyte layer 23 is formed on the positive electrode layer 21.

[0116] Next, a negative electrode layer 22 is formed on the solid electrolyte layer 23 in the same manner as the formation of the positive electrode layer 21 and the solid electrolyte layer 23.

[0117] Thereby, as shown in FIG. 7A, the electrode laminate 2 is formed on the first base material F1.

[0118] The material of the first base material F1 is not limited as long as it can be electrostatic screen-printed. Examples of the material of the first base material F1 include metal foil. Examples of the metal foil include aluminum foil.

[0119] Note that as long as the electrode laminate 2 can be formed, the formation order of the positive electrode layer 21, the negative electrode layer 22, and the solid electrolyte layer 23 is not limited. The negative electrode layer 22 may be formed on the first base material F1, the solid electrolyte layer 23 may be formed on the negative electrode layer 22, and the positive electrode layer 21 may be formed on the solid electrolyte layer 23.

[0120] (2) Pressing step The pressing step is performed after the electrode laminate forming step. As shown in FIG. 7B, in the pressing step, a second base material F2 is laminated on the electrode laminate 2, and the obtained laminate L is pressed. Note that the obtained laminate L is a laminate of the first base material F1, the electrode laminate 2, and the second base material F2.

[0121] The material of the second base material F2 may be the same as or different from the material of the first base material F1.

[0122] The pressure applied to the laminate L is not limited as long as the electrode laminate 2 can be formed. The pressure applied to the laminate L is, for example, 50 MPa or more, preferably 300 MPa or more, and for example, 5000 MPa or less, preferably 3000 MPa or less.

[0123] (3) Cutting step The cutting step is performed after the pressing step. In the cutting step, the electrode laminate 2 is cut into a desired shape. In this embodiment, the electrode laminate 2 is cut into a substantially rectangular shape when viewed from the thickness direction of the electrode laminate 2.

[0124] (4) Peeling process The peeling process is carried out after the cutting process. Note that the peeling process may be carried out before the cutting process. In the peeling process, as shown in FIG. 7C, at least one of the first substrate F1 and the second substrate F2 is peeled off from the electrode laminate 2. In the present embodiment, both the first substrate F1 and the second substrate F2 are peeled off from the electrode laminate 2. Note that, in order to prevent the electrode laminate 2 from collapsing, only one of the first substrate F1 and the second substrate F2 may be peeled off from the electrode laminate 2.

[0125] (5) Laminating process In the laminating process, as shown in FIG. 1B, the electrode laminate 2 and the current collector 3 (see FIG. 3B) are laminated alternately. By laminating each of the electrode laminate 2 and the current collector 3 in a desired number, the laminating process is completed.

[0126] After the laminating process, as shown in FIG. 4, the positive electrode tab 312A is joined to the positive electrode lead 4, and the negative electrode tab 312B is joined to the negative electrode lead 5, and the laminate of the electrode laminate 2 and the current collector 3 is vacuum-packed with the exterior material 6.

[0127] Thus, the manufacturing of the all-solid-state battery 1 is completed.

[0128] 3. Manufacturing system of all-solid-state battery Next, a manufacturing system 10 of an all-solid-state battery capable of implementing the manufacturing method of the all-solid-state battery 1 will be described. As shown in FIG. 8, the manufacturing system 10 of the all-solid-state battery 1 includes a granulating section 11, a pulverizing section 12, a mixing section 13, an electrode laminate forming section 14, and a laminating section 15.

[0129] (1) Granulating section The granulating section 11 is capable of executing the above-described granulating process (see FIG. 5). The granulating section 11 agglomerates the powder of the solid electrolyte in a dry manner to form the first granule. The granulating section 11 includes a granulating device 111. The granulating section 11 may include a removing device for removing fine powder.

[0130] The granulation device 111 forms the first granule. The granulation device 111 is not limited as long as it can agglomerate the powder of the solid electrolyte in a dry manner. Examples of the granulation device 111 include a rolling granulator and a stirring granulator. Preferably, the granulation device 111 is a rolling granulator.

[0131] (2) Crushing section The crushing section 12 is capable of performing the above-described crushing process (see FIG. 5). The crushing section 12 crushes the first granule to form a second granule smaller than the first granule. The crushing section 12 includes a grinding device 121 and a removing device 122.

[0132] The grinding device 121 grinds the first granule. The grinding device 121 is not limited as long as it can crush the first granule by a shearing force and make the particle size of the obtained second granule uniform. Examples of the grinding device 121 include a stone mill, a kneader, and an edge runner. Preferably, the grinding device 121 is a stone mill.

[0133] The removing device 122 is capable of performing the above-described removing process (see FIG. 5). The removing device 122 removes fine powder. The removing device 122 is not limited as long as it can separate the second granule and the fine powder and remove the fine powder. Examples of the removing device 122 include a cyclone separator, an inertial classifier, and a sieve. The fine powder removed by the removing device 122 may be used again as a powder material.

[0134] (3) Mixing section The mixing section 13 is capable of performing the above-described mixing process. The mixing section 13 mixes the powder of the solid electrolyte and the powder of the positive electrode active material or the negative electrode active material. The mixing section 13 includes a mixing device 131. The mixing device 131 is not limited. Examples of the mixing device 131 include a dry mixing device such as a ball mill.

[0135] Specifically, the mixing unit 13 includes a plurality of mixing devices 131A and 131B. The mixing device 131A mixes the powder of the solid electrolyte and the powder of the positive electrode active material to prepare a positive electrode composite material. The mixing device 131B mixes the powder of the solid electrolyte and the powder of the negative electrode active material to prepare a negative electrode composite material.

[0136] (4) Electrode laminate forming section The electrode laminate forming section 14 is capable of performing the above-described electrode laminate forming process (see FIGS. 6A to 7A), the pressing process (see FIG. 7B), and the cutting process. In the present embodiment, the electrode laminate forming section 14 includes an electrostatic screen printing device 141, a pressing device 142, and a cutting device 143.

[0137] Specifically, the electrode laminate forming section 14 includes a plurality of electrostatic screen printing devices 141A, 141B, and 141C. The electrostatic screen printing device 141A forms a positive electrode layer 21 on the first base material F1 using the positive electrode composite material prepared by the mixing device 131A (see FIGS. 6A and 6B). The electrostatic screen printing device 141B forms a solid electrolyte layer 23 on the positive electrode layer 21 using the second granule prepared by the grinding device 121. The electrostatic screen printing device 141C forms a negative electrode layer 22 on the solid electrolyte layer 23 using the negative electrode composite material prepared by the mixing device 131B. That is, the electrode laminate forming section 14 deposits the second granule on the first base material F1 in a dry manner to form the electrode laminate 2.

[0138] The pressing device 142 is capable of performing the above-described pressing process (see FIG. 7B). The pressing device 142 laminates the second base material F2 on the electrode laminate 2 and presses the obtained laminate L.

[0139] The cutting device 143 is capable of performing the above-described cutting process. The cutting device cuts the electrode laminate 2 into a desired shape.

[0140] (5) Laminating section The lamination unit 15 is capable of performing the above-described peeling process (see FIG. 7C) and the lamination process. The lamination unit 15 laminates the electrode laminate 2 and the current collector 3. The lamination unit 15 includes a laminating device 151. As shown in FIG. 7C, the laminating device 151 peels off at least one of the first base material F1 and the second base material F2 from the electrode laminate 2, and as shown in FIG. 1B, alternately laminates the electrode laminate 2 and the current collector 3.

[0141] 4. Operational Effects (1) According to the manufacturing method of the all-solid-state battery 1, as shown in FIG. 5, in the granulation process, after aggregating the powder of the solid electrolyte to form the first granule, in the pulverization process, the first granule is crushed to form a second granule smaller than the first granule.

[0142] Therefore, by aggregating the powder of the solid electrolyte in the granulation process, the fluidity can be improved.

[0143] Furthermore, by crushing the first granule in the pulverization process, it is possible to suppress the situation where coarse granules hinder the thinning of the solid electrolyte layer 23 (see FIG. 2A).

[0144] As a result, it is possible to achieve thinning of the solid electrolyte layer 23 and uniformization of the thickness of the solid electrolyte layer 23.

[0145] (2) According to the manufacturing method of the all-solid-state battery 1, the granulation process and the pulverization process are performed dry.

[0146] Therefore, when forming the solid electrolyte layer 23 dry from the powder of the solid electrolyte with low fluidity, it is possible to achieve thinning of the solid electrolyte layer 23 and uniformization of the thickness of the solid electrolyte layer 23.

[0147] (3) According to the manufacturing method of the all-solid-state battery 1, the median diameter (d50) of the powder of the solid electrolyte is less than 10 μm on a number basis. When the median diameter is less than 10 μm, the fluidity may be low.

[0148] In this regard, according to the manufacturing method of the all-solid-state battery 1, as described above, in the granulation step, after aggregating the solid electrolyte powder to form the first granule, in the pulverization step, the first granule is crushed to form a second granule smaller than the first granule.

[0149] Therefore, even when the median diameter of the solid electrolyte powder is small and the fluidity is low, it is possible to reduce the thickness of the solid electrolyte layer 23 and make the thickness of the solid electrolyte layer 23 uniform.

[0150] (4) According to the manufacturing method of the all-solid-state battery 1, the median diameter (d50) of the second granule is 30 μm or less on a number basis.

[0151] Since the median diameter of the second granule is 30 μm or less, it is possible to prevent coarse granules from hindering the thinning of the solid electrolyte layer 23.

[0152] (5) According to the manufacturing method of the all-solid-state battery 1, in the pulverization step, the first granule is ground.

[0153] Therefore, the particle diameter of the second granule can be made uniform, and the shape of the second granule can be made closer to a spherical shape.

[0154] (6) According to the manufacturing method of the all-solid-state battery 1, as shown in FIG. 5, after the pulverization step and before the electrode laminate forming step, a removal step of removing fine powder is performed.

[0155] According to such a method, by removing the fine powder, the fluidity of the second granule can be further improved.

[0156] (7) According to the manufacturing system 10 of the all-solid-state battery 1, as shown in FIG. 8, in the granulation unit 11, after aggregating the solid electrolyte powder to form the first granule, in the pulverization unit 12, the first granule is crushed to form a second granule smaller than the first granule.

[0157] Therefore, in the granulation unit 11, the solid electrolyte powder can be aggregated to improve the fluidity.

[0158] Furthermore, in the pulverizing unit 12, by pulverizing the first granule, it is possible to suppress the coarse granule from hindering the thinning of the solid electrolyte layer 23.

[0159] As a result, it is possible to thin the solid electrolyte layer 23 and to make the thickness of the solid electrolyte layer 23 uniform.

[0160] (8) According to the manufacturing system 10 of the all-solid-state battery 1, as shown in FIG. 8, the granulating unit 11 includes a granulating device 111, and the pulverizing unit 12 includes a grinding device 121 and a removing device 122 for removing fine powder.

[0161] Therefore, by removing the fine powder, the fluidity of the second granule can be further improved.

[0162] 5. Modification Hereinafter, the modification will be described. In the modification, the same members as those in the above-described embodiment are denoted by the same reference numerals, and the description thereof will be omitted.

[0163] (1) In the above-described embodiment, the second granule was prepared using the powder of the solid electrolyte, and the solid electrolyte layer 23 was formed using the obtained second granule. However, the second granule may be blended with the positive electrode composite material or the negative electrode composite material. That is, the second granule may be the particle constituting the positive electrode layer 21, the negative electrode layer 22, and the solid electrolyte layer 23.

[0164] (2) Further, the powder material may contain a solid electrolyte and an active material (positive electrode active material or negative electrode active material). In this case, the powder material containing the solid electrolyte and the active material (positive electrode active material or negative electrode active material) is aggregated to prepare a first granule containing the solid electrolyte and the active material, the obtained first granule is pulverized to prepare a second granule, and the obtained second granule may be used to form the positive electrode layer 21 and the negative electrode layer 22. That is, the second granule may be the particle constituting the positive electrode layer 21, the negative electrode layer 22, and the solid electrolyte layer 23.

[0165] (3) In the above-described embodiment, the electrode laminate 2 is formed by a dry process, but it may also be formed by a wet process. For example, a powder containing the second granule may be dispersed in a solvent to prepare a slurry, and the obtained slurry may be applied onto a substrate and dried to form the electrode laminate 2.

[0166] (4) Even in Modifications (1), (2), and (3), the same operational effects as those of the above-described embodiment can be obtained.

Description of Reference Numerals

[0167] 1 All-solid-state battery 2 Electrode laminate 3 Current collector 10 Manufacturing system 11 Granulation section 111 Granulation device 12 Crushing section 121 Grinding device 122 Removal device 14 Electrode laminate forming section 15 Laminating section

Claims

1. A granulation step of aggregating a powder material to form a first granule, a pulverization step of pulverizing the first granule to form a second granule smaller than the first granule, an electrode laminate forming step of depositing the second granule on a substrate to form an electrode laminate, and a lamination step of laminating the electrode laminate and a current collector A method for manufacturing an all-solid-state battery, comprising:

2. The method for manufacturing an all-solid-state battery according to claim 1, wherein the granulation step and the pulverization step are performed dry.

3. The method for manufacturing an all-solid-state battery according to claim 1, wherein the median diameter (d50) of the powder material measured by the laser diffraction / scattering method is less than 10 μm on a number basis.

4. The method for manufacturing an all-solid-state battery according to claim 1, wherein the median diameter (d50) of the second granule measured by the laser diffraction / scattering method is 30 μm or less on a number basis.

5. The method for manufacturing an all-solid-state battery according to claim 1, wherein in the pulverization step, the first granule is ground.

6. The method for manufacturing an all-solid-state battery according to claim 1, further comprising a removal step of removing fine powder at least at one of the timings after the granulation step, before the pulverization step, and after the pulverization step and before the electrode laminate forming step.

7. The method for manufacturing an all-solid-state battery according to claim 1, wherein the powder material is a powder containing a solid electrolyte.

8. A granulation unit that aggregates a powder material to form a first granule, a pulverization unit that pulverizes the first granule to form a second granule smaller than the first granule, an electrode laminate forming unit that deposits the second granule on a substrate to form an electrode laminate, and a lamination unit that laminates the electrode laminate and a current collector An all-solid-state battery manufacturing system having:

9. The granulation unit includes a granulation device that forms the first granule, the pulverization unit includes a grinding device that grinds the first granule, The all-solid-state battery manufacturing system according to claim 8, wherein at least one of the granulation unit and the pulverization unit further includes a removal device that removes fine powder.

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