All-solid-state battery

Abstract

An all-solid-state battery according to an embodiment is provided with: a positive electrode; a negative electrode; a solid electrolyte layer between the positive electrode and the negative electrode; and a first columnar body located in the same layer as the positive electrode or the negative electrode at a position separated from the positive electrode or the negative electrode with a gap therebetween.

Description

Technical Field

[0001] The present invention relates to all-solid-state batteries. This application claims priority to the content described in Japanese Patent Application No. 2022-203082 filed on December 20, 2022. Background Art

[0002] In recent years, the development of electronic technology has been remarkable. Portable electronic devices have achieved miniaturization, light weight, thinness, and multifunctionality. Accordingly, there is a strong expectation for batteries, which are the power sources of electronic devices, to also achieve miniaturization, light weight, thinness, and improved reliability, and all-solid-state batteries using solid electrolytes as electrolytes have attracted much attention.

[0003] All-solid-state batteries are charged and discharged by lithium ions moving between a positive electrode and a negative electrode via a solid electrolyte. For example, Patent Document 1 discloses an all-solid-state battery using a sintered solid electrolyte.

[0004] Prior Art Documents

[0005] Patent Documents

[0006] Patent Document 1: WO 2008 / 099508 Summary of the Invention

[0007] Problems to be Solved by the Invention

[0008] In the case of sintered all-solid-state batteries, due to stress concentration at the interfaces of each layer caused by sintering mismatch during sintering and volume expansion during charge and discharge, cracks sometimes occur inside. The internal cracks are the cause of the deterioration of the cycle characteristics of all-solid-state batteries.

[0009] The present disclosure has been made in view of the above problems, and an object thereof is to provide an all-solid-state battery in which internal cracks are less likely to occur.

[0010] Means for Solving the Problems

[0011] In order to solve the above technical problems, the following technical means are provided.

[0012] (1) A first aspect provides an all-solid-state battery including a positive electrode, a negative electrode, a solid electrolyte layer, and a first columnar body. The solid electrolyte layer is disposed between the positive electrode and the negative electrode. The first columnar body is disposed in the same layer as the positive electrode or the negative electrode at a position separated from the positive electrode or the negative electrode by a gap.

[0013] (2) In the all-solid-state battery according to the above aspect, the first columnar body may be separated from the positive electrode by a gap in the same layer as the positive electrode.

[0014] (3) The all-solid-state battery of the above-described manner may further include a second columnar body. The second columnar body is separated from the negative electrode with a gap within the same layer as the negative electrode.

[0015] (4) The all-solid-state battery of the above-described manner may further include a positive terminal and a negative terminal. The positive terminal is connected to the positive electrode on the first surface of the laminate including the positive electrode, the negative electrode, and the solid electrolyte layer. The negative terminal is connected to the negative electrode on the second surface of the laminate different from the first surface. The first columnar body is located between the positive terminal and the negative electrode, or between the negative terminal and the positive electrode.

[0016] (5) In the all-solid-state battery of the above-described manner, it may also be that the positive terminal is in contact with the first surface and the surface adjacent to the first surface, and the positive terminal is not in contact with the negative electrode.

[0017] (6) In the all-solid-state battery of the above-described manner, it may also be that the negative terminal is in contact with the second surface and the surface adjacent to the second surface, and the negative terminal is not in contact with the positive electrode.

[0018] (7) In the all-solid-state battery of the above-described manner, it may also be that the first columnar body has the same layer structure as the positive electrode or the negative electrode.

[0019] (8) In the all-solid-state battery of the above-described manner, it may also be that the thickness of the positive electrode is 2.5 times or more the thickness of the solid electrolyte layer.

[0020] (9) In the all-solid-state battery of the above-described manner, it may also be that the thickness of the negative electrode is 2.5 times or more the thickness of the solid electrolyte layer.

[0021] (10) In the all-solid-state battery of the above-described manner, it may also be that the thickness of the positive electrode is 10 μm or more.

[0022] (11) In the all-solid-state battery of the above-described manner, it may also be that the thickness of the negative electrode is 10 μm or more.

[0023] (12) In the all-solid-state battery of the above-described manner, it may also be that the positive electrode is at least one layer or more, the negative electrode is at least one layer or more, and the total number of the positive electrode and the negative electrode is 3 or more.

[0024] (13) In the all-solid-state battery of this embodiment, it is also possible that the laminate including the positive electrode, the negative electrode, and the solid electrolyte layer has a first positive electrode and a second positive electrode adjacent to each other in the stacking direction. When viewed in the stacking direction of the laminate, a first gap between the first positive electrode and the columnar body within the same layer as the first positive electrode and a second gap between the second positive electrode and the columnar body within the same layer as the second positive electrode overlap at least partially.

[0025] (14) In the all-solid-state battery of this embodiment, it is also possible that when viewed in the stacking direction of the laminate, more than 80% of the first gap overlaps with the second gap.

[0026] (15) In the all-solid-state battery of this embodiment, it is also possible that the laminate including the positive electrode, the negative electrode, and the solid electrolyte layer has a first negative electrode and a second negative electrode adjacent to each other in the stacking direction. When viewed in the stacking direction of the laminate, a third gap between the first negative electrode and the columnar body within the same layer as the first negative electrode and a fourth gap between the second negative electrode and the columnar body within the same layer as the second negative electrode overlap at least partially.

[0027] (16) In the all-solid-state battery of this embodiment, it is also possible that when viewed in the stacking direction of the laminate, more than 80% of the third gap overlaps with the fourth gap.

[0028] (17) In the all-solid-state battery of this embodiment, it is also possible that in the same layer as the positive electrode or the negative electrode, a first region including the solid electrolyte constituting the solid electrolyte layer is provided between the positive electrode or the negative electrode and the first columnar body.

[0029] (18) In the all-solid-state battery of this embodiment, it is also possible that in the same layer as the positive electrode or the negative electrode, a third columnar body is provided between the positive electrode or the negative electrode and the first columnar body.

[0030] (19) In the all-solid-state battery of this embodiment, it is also possible that a part of the first columnar body or a fourth columnar body is located at the position of the positive electrode or the negative electrode in the second direction. Here, in the same layer as the positive electrode or the negative electrode, the direction from the first columnar body through the gap toward the positive electrode or the negative electrode is defined as the first direction, and the direction crossing the first direction is defined as the second direction.

[0031] (20)In the all-solid-state battery of the above-described mode, it is also possible that the width in the first direction of the void is 0.07 times or more and 15.0 times or less the width in the first direction of the first columnar body. Here, in the same layer as the positive electrode or the negative electrode, the direction from the first columnar body toward the positive electrode or the negative electrode across the void is defined as the first direction.

[0032] Advantages of the Invention

[0033] Internal cracks are less likely to occur in the all-solid-state battery of the above-described mode. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 is a cross-sectional view of the all-solid-state battery of the first embodiment.

[0035] Figure 2 is a cross-sectional view of the all-solid-state battery of the first embodiment cut along the positive electrode.

[0036] Figure 3 is a cross-sectional view of the all-solid-state battery of the first embodiment cut along the negative electrode.

[0037] Figure 4 is a cross-sectional view of a characteristic portion of the all-solid-state battery of the first embodiment.

[0038] Figure 5 is a cross-sectional view of a characteristic portion of the all-solid-state battery of the first modification.

[0039] Figure 6 is a cross-sectional view of a characteristic portion of the all-solid-state battery of the second modification.

[0040] Figure 7 is a cross-sectional view of a characteristic portion of the all-solid-state battery of the third modification.

[0041] Figure 8 is a cross-sectional view of a characteristic portion of the all-solid-state battery of the fourth modification.

[0042] Figure 9 is a cross-sectional view of a characteristic portion of the all-solid-state battery of the fifth modification.

[0043] Figure 10 is a cross-sectional view of the all-solid-state battery of the sixth modification cut along the positive electrode.

[0044] Figure 11 is a cross-sectional view of the all-solid-state battery of the sixth modification cut along the negative electrode.

[0045] Figure 12 is a cross-sectional view of a characteristic portion of the all-solid-state battery of the sixth modification.

[0046] Figure 13Cross-sectional view of a characteristic part of the all-solid-state battery of the sixth modified example. Detailed Description of the Preferred Embodiments

[0047] Hereinafter, the present embodiment will be described in detail with appropriate reference to the accompanying drawings. In the accompanying drawings used in the following description, for the sake of easy understanding of the features of the present invention, for convenience, the characteristic parts may be enlarged and shown, and the dimensional ratios of the respective components may sometimes be different from the actual ones. The materials, dimensions, etc. exemplified in the following description are merely examples, and the present invention is not limited to these, and can be appropriately changed and implemented without departing from the gist thereof.

[0048] The directions are defined. The stacking direction of the laminate 10 is defined as the z-direction, one direction in the plane orthogonal to the z-direction is defined as the x-direction, and the direction orthogonal to the x-direction and the z-direction is defined as the y-direction. The x-direction is, for example, the direction from the positive electrode terminal 80 toward the negative electrode terminal 90. For example, the direction from the columnar body 4 toward the positive electrode 1 within the same layer as the positive electrode 1 and the direction from the columnar body 6 toward the negative electrode 2 within the same layer as the negative electrode 2 are both examples of the x-direction. The x-direction is an example of the first direction. In addition, the y-direction is an example of the second direction. Hereinafter, one direction in the z-direction may be expressed as "up", and the direction opposite to this direction may be expressed as "down". The up and down do not necessarily coincide with the direction in which gravity is applied.

[0049] Figure 1 Cross-sectional view of the all-solid-state battery 100 of the first embodiment. Figure 2 Cross-sectional view of the all-solid-state battery 100 of the first embodiment cut along the positive electrode 1. Figure 3 Cross-sectional view of the all-solid-state battery 100 of the first embodiment cut along the negative electrode 2. Figure 4 Cross-sectional view of a characteristic part of the laminate 10 of the all-solid-state battery 100 of the first embodiment.

[0050] The all-solid-state battery 100 has, for example, a laminate 10, a positive electrode terminal 80, and a negative electrode terminal 90. The all-solid-state battery 100 is, for example, a laminated battery, a square battery, a cylindrical battery, a coin-type battery, a button-type battery, or the like. The all-solid-state battery 100 may also be a liquid-injection type in which the solid electrolyte layer 3 is dissolved or dispersed in a solvent.

[0051] <Laminate>

[0052] The laminate 10 has a positive electrode 1, a negative electrode 2, a solid electrolyte layer 3, a columnar body 4, and a columnar body 6. The columnar body 4 is within the same layer as the positive electrode 1. There is a gap 5 between the positive electrode 1 and the columnar body 4. The columnar body 6 is within the same layer as the negative electrode 2. There is a gap 7 between the negative electrode 2 and the columnar body 6. The columnar body 4 is an example of the first columnar body. The columnar body 6 is an example of the second columnar body.

[0053] The laminate 10 is charged or discharged by the transfer of ions between the positive electrode 1 and the negative electrode 2 via the solid electrolyte layer 3. The laminate 10 is, for example, a laminate formed by laminating three layers: the positive electrode 1, the negative electrode 2, and the solid electrolyte layer. The laminate 10 may also be, for example, a wound body formed by winding the laminate, which is formed by laminating three layers: the positive electrode 1, the negative electrode 2, and the solid electrolyte layer.

[0054] [Positive electrode]

[0055] The number of layers of the positive electrode 1 in the laminate 10 is not limited. The positive electrode 1 may be a single layer or multiple layers. Each positive electrode 1 extends in the xy plane. The first end of each positive electrode 1 is connected to the positive electrode terminal 80 on the first surface S1 of the laminate 10. The second end of each positive electrode 1 is exposed in the gap 5. The second end of each positive electrode 1 faces the columnar body 4 across the gap 5.

[0056] The thickness of the positive electrode 1 is, for example, 2.5 times or more the thickness of the solid electrolyte layer 3. The thickness of the positive electrode 1 is, for example, 10 μm or more.

[0057] As Figure 4 shown, the positive electrode 1 has, for example, a positive electrode current collector layer 11 and a positive electrode active material layer 12.

[0058] The positive electrode current collector layer 11 contains, for example, a material with high conductivity. The positive electrode current collector layer 11 is, for example, a metal or alloy containing at least one metal element of silver (Ag), palladium (Pd), gold (Au), platinum (Pt), aluminum (Al), copper (Cu), and nickel (Ni). In addition, for the positive electrode current collector layer 11, as long as it has conductivity, it may also be a non-metal such as carbon (C). The positive electrode current collector layer 11 is, for example, Ag or an AgPd alloy.

[0059] The positive electrode active material layer 12 is formed on one or both surfaces of the positive electrode current collector layer 11. The positive electrode active material layer 12 contains a positive electrode active material. The positive electrode active material layer 12 may also contain a conductive additive, a binder material, and the solid electrolyte described later.

[0060] The positive electrode active material is, for example, a transition metal oxide or a transition metal composite oxide. Specifically, the positive electrode active material is, for example, a lithium manganese composite oxide Li2Mn a Ma 1-a O3 (0.8 ≤ a ≤ 1, Ma = Co, Ni), lithium cobalt oxide (LiCoO2), lithium nickel oxide (LiNiO2), lithium manganese oxide (LiMn2O4) having a spinel structure, and a general formula LiNi x Co y Mn zComposite metal oxides represented by O2 (x + y + z = 1, 0 ≤ x ≤ 1, 0 ≤ y ≤ 1, 0 ≤ z ≤ 1), lithium vanadium compounds (LiV2O5), olivine-type LiMbPO4 (where Mb is one or more elements selected from Co, Ni, Mn, Fe, Mg, Nb, Ti, Al, Zr), lithium vanadium phosphate (Li3V2(PO4)3 or LiVOPO4), Li-excess solid solution cathodes represented by Li2MnO3−LiMcO2 (Mc = Mn, Co, Ni), lithium titanate (Li4Ti5O 12 ), titanium dioxide (TiO2), represented by Li s Ni t Co u Al v Composite metal oxides represented by O2 (0.9 < s < 1.3, 0.9 < t + u + v < 1.1), etc.

[0061] In addition, a part of each element constituting these cathode active materials may be substituted with different kinds of elements, and the composition ratios of these cathode active materials may also deviate from the stoichiometric composition.

[0062] Regarding the conductive additive, any preparation that can improve the electron conductivity within the cathode active material layer 12 is acceptable and there is no particular limitation. Known conductive additives can be used. Examples of conductive additives include: carbon materials such as graphite, carbon black, graphene, and carbon nanotubes; metals such as gold, platinum, silver, palladium, aluminum, copper, nickel, stainless steel, and iron; conductive oxides such as ITO; or mixtures thereof. The conductive additive can be in various forms such as powders and fibers.

[0063] The binder material joins the cathode current collector layer 11 and the cathode active material layer 12, and also joins the cathode active material layer 12 and the solid electrolyte layer 3. Moreover, the binder material joins various materials constituting the cathode active material layer 12 to each other.

[0064] The binder material can be used within the range that does not lose the function of the cathode active material layer 12. If the binder material is not required, the cathode active material layer 12 may not contain the binder material. The content of the binder material in the cathode active material layer 12 is, for example, 0.5 vol% or more and 30 vol% or less of the cathode active material layer. If the content of the binder material is sufficiently small, the resistance of the cathode active material layer 12 is sufficiently low. Here, vol% is approximately the same as the area% in the cross-section measured by a scanning electron microscope. The area ratio in the cross-section measured by a scanning electron microscope can be directly regarded as the volume ratio.

[0065] The bonding material only needs to be able to perform the above-mentioned bonding. For example, fluororesins such as polyvinylidene fluoride (PVDF) and polytetrafluoroethylene (PTFE) are examples of materials for the bonding material. In addition, the bonding material can also be, for example, cellulose, styrene-butadiene rubber, ethylene-propylene rubber, polyimide resin, polyamideimide resin, etc. In addition, the bonding material can also be a conductive polymer having electronic conductivity or an ion-conductive polymer having ion conductivity. A conductive polymer having electronic conductivity is, for example, polyacetylene. An ion-conductive polymer having ion conductivity is, for example, a product obtained by complexing a monomer of a polymer compound (such as a polyether polymer compound such as polyethylene oxide and polypropylene oxide, and polyphosphazene) with a lithium salt such as LiClO4, LiBF4, LiPF6 or an alkali metal salt mainly composed of lithium.

[0066] In Figure 4 an example in which the positive electrode 1 is composed of the positive electrode current collector layer 11 and the positive electrode active material layer 12 is shown, but the positive electrode 1 is not limited to this case. For example, the positive electrode 1 can also be a single layer in which the positive electrode current collector and the positive electrode active material are mixedly present.

[0067] [Negative electrode]

[0068] The number of layers of the negative electrode 2 in the laminate 10 is not limited. The negative electrode 2 can be single or multiple. The total number of layers of the positive electrode 1 and the negative electrode 2 in the laminate 10 is, for example, 3 or more.

[0069] The negative electrodes 2 extend in the xy plane respectively. The first end of each negative electrode 2 is connected to the negative electrode terminal 90 on the second surface S2 of the laminate 10. The first surface S1 and the second surface S2 are different surfaces of the laminate 10. For example, the first surface S1 faces the second surface S2. The second end of each negative electrode 2 is exposed in the gap 7. The second end of each negative electrode 2 faces the columnar body 6 across the gap 7.

[0070] The thickness of the negative electrode 2 is, for example, 2.5 times or more the thickness of the solid electrolyte layer 3. The thickness of the negative electrode 2 is, for example, 10 μm or more.

[0071] As Figure 4 shown, the negative electrode 2 has, for example, a negative electrode current collector layer 21 and a negative electrode active material layer 22.

[0072] The negative electrode current collector layer 21 contains, for example, a material with high conductivity. The negative electrode current collector layer 21 can use, for example, the same material as the positive electrode current collector layer 11. The negative electrode current collector layer 21 is, for example, Ag, an AgPd alloy.

[0073] The negative electrode active material layer 22 is formed on one or both surfaces of the negative electrode current collector layer 21. The negative electrode active material layer 22 contains a negative electrode active material. The negative electrode active material layer 22 may also contain a conductive assistant, a binder material, and a solid electrolyte described later.

[0074] The negative electrode active material is a compound capable of occluding / releasing ions. The negative electrode active material is a compound showing a potential lower than that of the positive electrode active material. The negative electrode active material can use the same material as the positive electrode active material. The negative electrode active material and the positive electrode active material used in the all-solid-state battery 100 are determined in consideration of the potential of the negative electrode active material and the potential of the positive electrode active material. The negative electrode active material is, for example, Li4Ti5O 12 , LiTiO2, Li2TiO3, Li2TiSiO5, or a mixture thereof.

[0075] The conductive assistant makes the electron conductivity of the negative electrode active material layer 22 good. The same material as that of the positive electrode active material layer 12 can be used as the conductive assistant.

[0076] The binder material joins the negative electrode current collector layer 21 and the negative electrode active material layer 22. The binder material also joins the negative electrode active material layer 22 and the solid electrolyte layer 3. Moreover, the binder material joins various materials constituting the negative electrode active material layer 22 to each other. The same material as that of the positive electrode active material layer 12 can be used as the binder material. The content ratio of the binder material can also be the same as that of the positive electrode active material layer 12. If the binder material is not required, the binder material may not be contained in the negative electrode current collector layer 21.

[0077] In Figure 4 an example in which the negative electrode 2 is composed of the negative electrode current collector layer 21 and the negative electrode active material layer 22 is shown, but the negative electrode 2 is not limited to this case. For example, the negative electrode 2 may also be a single layer in which the negative electrode current collector and the negative electrode active material exist mixedly.

[0078] [Solid electrolyte layer]

[0079] The solid electrolyte layer 3 is located between the positive electrode 1 and the negative electrode 2. The solid electrolyte layer 3 contains a solid electrolyte. The solid electrolyte is a substance that can move ions by an externally applied electric field. For example, the solid electrolyte layer 3 conducts lithium ions and hinders the movement of electrons. The solid electrolyte layer 3 is, for example, a sintered body obtained by sintering.

[0080] The solid electrolyte layer 3 preferably uses a substance with low electron conductivity and high lithium ion conductivity. For example, the solid electrolyte layer 3 is a substance such as La 0.5 Li 0.5 TiO3 and other perovskite-type compounds; Li 14LISICON-type compounds such as Zn(GeO4)4; Li7La3Zr2O 12 and garnet-type compounds such as; LiZr2(PO4)3, Li 1.3 Al 0.3 Ti 1.7 (PO4)3 and Li 1.5 Al 0.5 Ge 1.5 (PO4)3 and other NASICON-type compounds; Li 3.25 Ge 0.25 P 0.75 S4 and thio-LISICON-type compounds such as Li3PS4; glass compounds such as Li2S-P2S5 and Li2O-V2O5-SiO2; Li3PO4 and Li 3.5 Si 0.5 P 0.5 O4 and Li 2.9 PO 3.3 N 0.46 and other phosphoric acid compounds, etc.

[0081] The solid electrolyte layer 3 contains, for example, a solid electrolyte having a crystal structure of the γ-Li3PO4 type. The solid electrolyte having a crystal structure of the γ-Li3PO4 type has excellent ionic conductivity. The solid electrolyte is, for example: Li 3+x Si x P 1－ x O4, Li 3+x Si x V 1－x O4, Li 3+x Ge x P 1－x O4, Li 3+x Ge x V 1－x O4, etc., preferably Li 3+x Si x P 1－x O4. x satisfies 0.4 ≤ x ≤ 0.8. In addition, the solid electrolyte may also be a ternary type of lithium oxide containing Si, V, and Ge, etc.

[0082] [Columnar body]

[0083] The columnar body 4 is in the same layer as the positive electrode 1. The columnar body 4 is an example of the first columnar body. The columnar body 4 is located at a position separated from the positive electrode 1 by a gap 5. The columnar body 4 is located at a position shifted from the positive electrode 1 in the x direction by the gap 5. The columnar body 4 extends in the xy plane. The columnar body 4 is located between the positive electrode 1 and the negative terminal 90 in the x direction. The first side surface of the columnar body 4 in the x direction is exposed in the gap 5. The second side surface of the columnar body 4 in the x direction is in contact with the negative terminal 90, for example. The second side surface of the columnar body 4 in the x direction may also be separated from the negative terminal 90, for example. A gap may be provided between the columnar body 4 and the negative terminal 90.

[0084] The third side surface of the columnar body 4 in the y direction is exposed on the third surface S3 of the laminate 10, for example, and the fourth side surface of the columnar body 4 in the y direction is exposed on the fourth surface of the laminate 10, for example. The columnar body 4 extends from the third surface S3 to the fourth surface S4 of the laminate 10 in the y direction, for example. The columnar body 4 supports the solid electrolyte layer 3 adjacent to the positive electrode 1.

[0085] As Figure 4 shown, the columnar body 4 has a first layer 41 and a second layer 42, for example. The second layer 42 is formed on one or both surfaces of the first layer 41. For example, the second layer 42 sandwiches the first layer 41 in the z direction. The first layer 41 is made of the same material as the positive electrode current collector layer 11, for example. The second layer 42 is made of the same material as the positive electrode active material layer 12, for example. The columnar body 4 has the same layer structure as the positive electrode 1, for example. For example, the second layer 42 is made of the same material as the positive electrode active material layer 12 and has the same thickness. For example, the first layer 41 is made of the same material as the positive electrode current collector layer 11 and has the same thickness.

[0086] The thickness of the columnar body 4 is, for example, 2.5 times or more the thickness of the solid electrolyte layer 3. The thickness of the columnar body 4 is, for example, 10 μm or more.

[0087] The gap 5 is between the positive electrode 1 and the columnar body 4 in the same layer as the positive electrode 1. The gap 5 is exposed on the third surface S3 and the fourth surface S4 of the laminate 10, respectively, and extends from the third surface S3 to the fourth surface S4. The inside of the gap 5 may be a vacuum, may be filled with a gas, or may be filled with a liquid.

[0088] For example, when viewed from the z-direction, at least a part of the gaps 5 adjacent in the z-direction overlap. For example, when viewed from the z-direction, the first gap 5A and the second gap 5B overlap at least partially. For example, when viewed from the z-direction, more than 80% of the first gap 5A overlaps with the second gap 5B. The first gap 5A is a gap 5 within the same layer as the first positive electrode 1A. The first positive electrode 1A is one of the positive electrodes 1 in the laminate 10. The second gap 5B is a gap 5 within the same layer as the second positive electrode 1B. The second positive electrode 1B is a positive electrode 1 adjacent to the first positive electrode 1A in the z-direction in the laminate 10.

[0089] In addition, when the number of positive electrodes 1 is three or more, when viewed from the z-direction, at least a part of each of the gaps 5 within the same plane as each positive electrode 1 may also overlap with all the other gaps 5. In addition, for example, when viewed from the z-direction, more than 80% of the first gap 5A may also overlap with all the other gaps 5 respectively.

[0090] The columnar body 6 is within the same layer as the negative electrode 2. The columnar body 6 is an example of a second columnar body. The columnar body 6 is located at a position separated from the negative electrode 2 by the gap 7. The columnar body 6 is located at a position shifted from the negative electrode 2 in the x-direction by the gap 7. The columnar body 6 extends in the xy-plane. The columnar body 6 is located between the negative electrode 2 and the positive terminal 80 in the x-direction. The first side surface of the columnar body 6 in the x-direction is exposed in the gap 7. The second side surface of the columnar body 6 in the x-direction is in contact with the positive terminal 80, for example. The second side surface of the columnar body 6 in the x-direction may also be separated from the positive terminal 80, for example. A gap may also be provided between the columnar body 6 and the positive terminal 80.

[0091] The third side surface of the columnar body 6 in the y-direction is exposed on the third surface S3 of the laminate 10, for example, and the fourth side surface of the columnar body 6 in the y-direction is exposed on the fourth surface of the laminate 10, for example. The columnar body 6 extends from the third surface S3 to the fourth surface S4 of the laminate 10 in the y-direction, for example. The columnar body 6 supports the solid electrolyte layer 3 adjacent to the negative electrode 2.

[0092] As Figure 4 shown, the columnar body 6 has, for example, a first layer 61 and a second layer 62. The second layer 62 is formed on one or two surfaces of the first layer 61. For example, the second layer 62 sandwiches the first layer 61 in the z-direction. The first layer 61 is made of the same material as the negative electrode current collector layer 21, for example. The second layer 62 is made of the same material as the negative electrode active material layer 22, for example. The columnar body 6 has, for example, the same layer structure as the negative electrode 2. For example, the second layer 62 is made of the same material as the negative electrode active material layer 22 and has the same thickness. For example, the first layer 61 is made of the same material as the negative electrode current collector layer 21 and has the same thickness.

[0093] The thickness of the columnar body 6 is, for example, 2.5 times or more the thickness of the solid electrolyte layer 3. The thickness of the columnar body 6 is, for example, 10 μm or more.

[0094] The void 7 is between the negative electrode 2 and the columnar body 6 within the same layer as the negative electrode 2. The void 7 is, for example, exposed on the third surface S3 and the fourth surface S4 of the laminate 10 respectively, and extends from the third surface S3 to the fourth surface S4. The void 7 can be a vacuum, filled with gas, or filled with liquid.

[0095] For example, when viewed from the z direction, at least a part of the voids 7 adjacent in the z direction overlap. For example, when viewed from the z direction, the first void 7A and the second void 7B overlap at least partially. For example, when viewed from the z direction, 80% or more of the first void 7A overlaps with the second void 7B. The first void 7A is a void 7 within the same layer as the first negative electrode 2A. The first negative electrode 2A is one of the negative electrodes 2 in the laminate 10. The second void 7B is a void 7 within the same layer as the second negative electrode 2B. The second negative electrode 2B is a negative electrode 2 adjacent to the first negative electrode 2A in the z direction in the laminate 10.

[0096] In addition, when the number of the negative electrodes 2 is three or more, when viewed from the z direction, at least a part of each of the voids 7 within the same plane as each negative electrode 2 may also overlap with all the other voids 7. In addition, for example, when viewed from the z direction, 80% or more of the first void 7A may also overlap with all the other voids 7 respectively.

[0097] <Positive terminal>

[0098] The positive terminal 80 is in contact with the first surface S1 of the laminate 10. The positive terminal 80 covers the first surface S1 of the laminate 10. A part of the positive terminal 80 may also be wound into the surface adjacent to the first surface S1. The positive terminal 80 may also be in contact with the first surface S1 and the surfaces adjacent to the first surface (the third surface and the fourth surface). For example, the positive terminal 80 may also cover a part of the third surface S3 and the fourth surface S4 of the laminate 10. The positive terminal 80 covering the third surface S3 and the fourth surface S4 is not in contact with the negative electrodes 2 respectively. The positive terminal 80 contains a conductive material. The positive terminal 80 may also contain, for example, the same material as the positive current collector layer 11. The positive terminal 80 is responsible for the electrical conduction between the laminate 10 and the external pad.

[0099] <Negative terminal>

[0100] The negative terminal 90 is in contact with the second surface S2 of the laminate 10. The negative terminal 90 covers the second surface S2 of the laminate 10. A part of the negative terminal 90 may also be wound into the surface adjacent to the second surface S2. The negative terminal 90 may also be in contact with the second surface S2 and the surfaces adjacent to the second surface (the third surface and the fourth surface). For example, the negative terminal 90 may also cover a part of the third surface S3 and the fourth surface S4 of the laminate 10. The negative terminal 90 covering the third surface S3 and the fourth surface S4 is not in contact with the positive electrode 1 respectively. The negative terminal 90 contains a conductive material. The negative terminal 90 may also contain, for example, the same material as the negative current collector layer 21. The negative terminal 90 is responsible for the electrical conduction between the laminate 10 and the external pad.

[0101] [Manufacturing Method of All-Solid-State Battery]

[0102] A manufacturing method of the all-solid-state battery 100 will be described. First, the laminate 10 is fabricated. The laminate 10 is fabricated by, for example, a simultaneous firing method or a sequential firing method.

[0103] The simultaneous firing method is a method of fabricating the laminate 10 by firing all the layers together after laminating the materials for forming the respective layers. The sequential firing method is a method of firing each layer every time it is formed. The laminate 10 can be fabricated by fewer operation steps by the simultaneous firing method than by the sequential firing method. In addition, the laminate 10 fabricated by the simultaneous firing method is denser than the laminate 10 fabricated by the sequential firing method. Hereinafter, an example of using the simultaneous firing method will be described.

[0104] First, the materials of the positive current collector layer 11, the positive electrode active material layer 12, the solid electrolyte layer 3, the negative electrode active material layer 22, and the negative current collector layer 21 that constitute the laminate 10 are made into pastes. There is no particular limitation on the method of making the respective materials into pastes. For example, a method of obtaining a paste by mixing the powders of the respective materials into a carrier can be used. Here, the carrier is a general term for the medium in the liquid phase. The carrier contains a solvent and a binder.

[0105] Next, green sheets are fabricated. The green sheets are obtained by the following method: The paste made for each material is coated on a substrate such as a PET (polyethylene terephthalate) film, and after drying as needed, the substrate is peeled off. There is no particular limitation on the method of coating the paste. For example, known methods such as a screen printing method, a coating method, a transfer method, and a doctor blade method can be used.

[0106] The first layer 41 of the columnar body 4 can be formed simultaneously when the positive electrode current collector layer 11 is coated. The second layer 42 of the columnar body 4 can be formed simultaneously when the positive electrode active material layer 12 is coated. When the paste of the positive electrode 1 is coated while masking the portion that becomes the gap 5, the columnar body 4 is formed. In addition, the portion that becomes the gap 5 can also be filled with a sacrificial material that sublimes by heating. When the laminate is sintered, the sacrificial material sublimes to form the gap 5. The sacrificial material is, for example, the same material as the binder.

[0107] The first layer 61 of the columnar body 6 can be formed simultaneously when the negative electrode current collector layer 21 is coated. The second layer 62 of the columnar body 6 is formed simultaneously when the negative electrode active material layer 22 is coated. When the paste of the negative electrode 2 is coated while masking the portion that becomes the gap 7, the columnar body 6 is formed. In addition, the portion that becomes the gap 7 can also be filled with a sacrificial material that sublimes by heating. When the laminate is sintered, the sacrificial material sublimes to form the gap 7. The sacrificial material is, for example, the same material as the binder.

[0108] Next, green sheets made of each material are laminated in a desired order and number of layers to produce a laminated sheet. When laminating the green sheets, alignment and cutting are performed as needed. For example, in the case of manufacturing a parallel type or series-parallel type battery, alignment is performed such that the end faces of the positive electrode current collector layer 11 and the negative electrode current collector layer 21 do not match, and the respective green sheets are laminated.

[0109] The laminated sheet can also be produced by a method in which a positive electrode unit and a negative electrode unit are first produced and then these units are laminated. The positive electrode unit is a laminated sheet in which the solid electrolyte layer 3, the positive electrode active material layer 12, the positive electrode current collector layer 11, and the positive electrode active material layer 12 are laminated in this order. The first layer 41 is formed in the same plane as the positive electrode current collector layer 11, and the second layer 42 is formed in the same plane as the positive electrode active material layer 12. The negative electrode unit is a laminated sheet in which the solid electrolyte layer 3, the negative electrode active material layer 22, the negative electrode current collector layer 21, and the negative electrode active material layer 22 are laminated in this order. The first layer 61 is formed in the same plane as the negative electrode current collector layer 21, and the second layer 62 is formed in the same plane as the negative electrode active material layer 22. Lamination is performed such that the solid electrolyte layer 3 of the positive electrode unit faces the negative electrode active material layer 22 of the negative electrode unit, or such that the positive electrode active material layer 12 of the positive electrode unit faces the solid electrolyte layer 3 of the negative electrode unit.

[0110] Next, the fabricated laminated sheet is pressed together to improve the adhesion of each layer. Pressing can be performed, for example, using a molding press, a warm isostatic press (WIP), a cold isostatic press (CIP), a static press, etc. Pressing is preferably performed while heating. The heating temperature during pressing is set, for example, to 40°C to 95°C. Next, the pressed laminate is cut using a cutting device to chip it. Then, by performing a debinding treatment and firing on the chip, a laminate 10 composed of a sintered body is obtained.

[0111] The debinding treatment is performed as a process different from the firing process. By performing the debinding process, the binder component contained in the chip is heated and decomposed before the firing process, and it is possible to suppress the rapid decomposition of the binder component during the firing process. In the debinding process, for example, in an air atmosphere, the laminate is heated at a temperature of 300°C or higher and 800°C or lower for a time of 0.1 hour or longer and 10 hours or shorter. The atmosphere of the debinding process is an atmosphere in which the oxygen partial pressure does not cause or hardly causes redox reactions of the materials constituting the positive electrode, negative electrode, and solid electrolyte. The gas type in the debinding process can be arbitrarily selected so that the materials constituting the positive electrode, negative electrode, and solid electrolyte do not react with the atmosphere gas. For example, the debinding process can also be performed in a nitrogen atmosphere, an argon atmosphere, a nitrogen-hydrogen mixed atmosphere, a water vapor atmosphere, or an atmosphere in which they are mixed.

[0112] The firing process is performed, for example, under the condition of placing the chip on a ceramic stage. Firing is performed, for example, by heating the laminate to 600°C to 1000°C in a nitrogen atmosphere. The firing time is set, for example, to 0.1 hour to 3 hours. The atmosphere of the sintering process is an atmosphere in which the oxygen partial pressure does not cause or hardly causes redox reactions of the materials constituting the positive electrode, negative electrode, and solid electrolyte. The gas type in the sintering process can be arbitrarily selected so that the materials constituting the positive electrode, negative electrode, and solid electrolyte do not react with the atmosphere gas. For example, the firing process can also be performed in a nitrogen atmosphere, an argon atmosphere, a nitrogen-hydrogen mixed atmosphere, a water vapor atmosphere, or an atmosphere in which they are mixed.

[0113] In addition, the sintered laminate 10 can be put into a cylindrical container together with a grinding material such as alumina for barrel grinding. Thereby, chamfering of the corners of the laminate 10 can be performed. Grinding can also be performed by sandblasting. Sandblasting can cut only specific parts, so it is preferred.

[0114] A positive electrode terminal 80 is formed on the first surface S1 of the produced laminate 10, and a negative electrode terminal 90 is formed on the second surface S2. The positive electrode terminal 80 and the negative electrode terminal 90 can be formed by methods such as sputtering, impregnation coating, screen printing, and spraying. By going through the above processes, a all-solid-state battery 100 can be produced. When forming the positive electrode terminal 80 and the negative electrode terminal 90 only in specified portions, masking is performed using tape or the like, and thus the above treatment is carried out.

[0115] The all-solid-state battery 100 of the present embodiment includes a columnar body 4 and a columnar body 6. The columnar body 4 and the columnar body 6 support the solid electrolyte layer 3 adjacent to the columnar body 4 or the columnar body 6. During pressing and firing during manufacturing, the columnar body 4 and the columnar body 6 can suppress stress concentration on the solid electrolyte layer 3. In addition, when the all-solid-state battery 100 has voids 5 and 7, the voids 5 and 7 relieve the stress applied inside the all-solid-state battery 100. Therefore, even when the volume of the positive electrode active material layer 12 and the negative electrode active material layer 22 changes during charge and discharge of the all-solid-state battery 100, resulting in strain inside the all-solid-state battery 100, cracks generated inside the all-solid-state battery 100 can be suppressed.

[0116] As described above, embodiments of the present invention have been described in detail with reference to the drawings, but each structure and their combinations in each embodiment are merely examples, and additions, omissions, replacements, and other changes of the structure can be made without departing from the gist of the present invention.

[0117] For example, Figure 5 is a cross-sectional view of a laminate 10A of an all-solid-state battery according to a first modification. The structures of the columnar body 4 and the columnar body 6 of the laminate 10A are different from those of the laminate 10. The columnar body 4 and the columnar body 6 in the laminate 10A are composed of a single layer. In Figure 5 an example in which both the columnar body 4 and the columnar body 6 are single layers is shown, but only either one of the columnar body 4 and the columnar body 6 may be a single layer. Even when the columnar body 4 or the columnar body 6 is a single layer, it can support the adjacent solid electrolyte layer 3, and thus, the same effects as those of the laminate 10 can be achieved. There is no particular limitation on the material of the columnar body 4 and the columnar body 6 constituting the single layer. For example, the single-layer columnar body 4 and columnar body 6 contain the same material as the solid electrolyte constituting the solid electrolyte layer 3.

[0118] In addition, for example, Figure 6FIG. 0 is a cross-sectional view of the laminate 10B of the all-solid-state battery according to the second modified example. The laminate 10B is different from the laminate 10 in that the laminate 10B does not have the columnar body 6 and the void 7. That is, the laminate 10B has the columnar body 4 and the void 5 only in the same layer as the positive electrode 1. In the laminate 10B, the portions where the columnar body 6 and the void 7 originally existed in the laminate 10 are filled with a solid electrolyte identical to the solid electrolyte layer 3. Similar to the first modified example, the columnar body 4 can also be a single layer.

[0119] In addition, for example, Figure 7 FIG. 5 is a cross-sectional view of the laminate 10C of the all-solid-state battery according to the third modified example. The laminate 10C is different from the laminate 10 in that the laminate 10C does not have the columnar body 4 and the void 5. That is, the laminate 10C has the columnar body 6 and the void 7 only in the same layer as the negative electrode 2. The columnar body 6 at this time is an example of the first columnar body. In the laminate 10C, the portions where the columnar body 4 and the void 5 originally existed in the laminate 10 are filled with a solid electrolyte identical to the solid electrolyte layer 3. Similar to the first modified example, the columnar body 6 can also be a single layer.

[0120] As shown in the second and third modified examples, even when the columnar body and the void are provided only in the layer of either the positive electrode 1 or the negative electrode 2, the same effects as those of the laminate 10 are achieved.

[0121] In addition, for example, Figure 8 FIG. 13 is a cross-sectional view of the laminate 10D of the all-solid-state battery according to the fourth modified example. The laminate 10D is different from the laminate 10 in that the laminate 10D has the following structure: in the same layer as the positive electrode 1, a region 31 is provided between the positive electrode 1 and the columnar body 4, and the region 31 contains the solid electrolyte constituting the solid electrolyte layer 3; and in the same layer as the negative electrode 2, a region 32 is provided between the negative electrode 2 and the columnar body 6, and the region 32 contains the solid electrolyte constituting the solid electrolyte layer 3. The region 31 is a portion where a part of the solid electrolyte layer 3 protrudes into the void 5. The region 32 is a portion where a part of the solid electrolyte layer 3 protrudes into the void 7. By having a part of the solid electrolyte layer 3 protrude into the voids 5 and 7, the stress applied inside the solid electrolyte layer 3 can be alleviated.

[0122] In the laminate 10D, it is not necessary for both the region 31 and the region 32 to exist, and either one of them may exist. In the laminate 10D, the columnar body 4 and the columnar body 6 can also be single layers. In addition, similar to the second and third modified examples, the laminate 10D may not have either the columnar body 4 or the columnar body 6.

[0123] In addition, for example, Figure 9It is a cross-sectional view of the laminate 10E of the all-solid-state battery of the fifth modified example. The laminate 10E is different from the laminate 10 in that the laminate 10E has the following structure: in the same layer as the positive electrode 1, a columnar body 8 is further provided between the positive electrode 1 and the columnar body 4; and in the same layer as the negative electrode 2, a columnar body 9 is further provided between the negative electrode 2 and the columnar body 6. The columnar body 8 and the columnar body 9 are examples of the third columnar body.

[0124] The laminate 10E has a plurality of columnar bodies in the same layer as the positive electrode 1 or the negative electrode 2. In Figure 9 An example in which there are two columnar bodies in the same layer is shown, but the number of columnar bodies can also be three or more. When there are a plurality of columnar bodies in the layer, the force on each columnar body is dispersed. As a result, it is difficult for the laminate 10E to generate strain inside.

[0125] The gap 5 between the positive electrode 1 and the columnar body 4 is divided into a gap 51 and a gap 52 by the columnar body 8. The gap 7 between the negative electrode 2 and the columnar body 6 is divided into a gap 71 and a gap 72 by the columnar body 9. The columnar body 8 can be a single layer or a laminate of multiple layers. For example, the columnar body 8 has the same structure as the columnar body 4. The columnar body 9 can be a single layer or a laminate of multiple layers. For example, the columnar body 9 has the same structure as the columnar body 6.

[0126] In the laminate 10E, it is not necessary for both the columnar body 8 and the columnar body 9 to exist, and only either one of them can exist. The laminate 10E can also have the following structure, that is, a layer having a plurality of columnar bodies in the layer and a layer having one columnar body in the layer are mixedly present. In addition, the laminate 10E can also be the same as the second modified example and the third modified example, and sometimes does not have a columnar body in the same layer as the positive electrode 1 or the negative electrode 2.

[0127] In addition, for example, Figure 10 It is a cross-sectional view of the all-solid-state battery of the sixth modified example cut along the positive electrode 1. Figure 11 It is a cross-sectional view of the all-solid-state battery of the sixth modified example cut along the negative electrode 2. Figure 12 It is a cross-sectional view of the laminate 10F of the sixth modified example cut along the xz plane. Figure 13 It is a cross-sectional view of the laminate 10F of the sixth modified example cut along the yz plane.

[0128] The columnar body 4 has a first part 45, a second part 46, and a third part 47. The first part 45 is located at a position in the x direction of the positive electrode 1 with a gap 5 therebetween. The second part 46 is located at a position in the y direction of the positive electrode 1 with a gap 55 therebetween. The third part 47 is located at a position in the y direction of the positive electrode 1 with a gap 56 therebetween. The second part 46 and the third part 47 sandwich the positive electrode 1 in the y direction. A part of the columnar body 4 is located at a position in the y direction of the positive electrode 1. Here, an example of the columnar body 4 in which the first part 45, the second part 46, and the third part 47 are connected is shown. However, it is also possible that the first part 45 and the second part 46 are separated, and the first part 45 and the third part 47 are separated. In the case where they are separated, the second part 46 and the third part 47 are each an example of a fourth columnar body. The layer structures of the first part 45, the second part 46, and the third part 47 can be single layers respectively, or structures in which multiple layers are stacked.

[0129] The columnar body 6 has a first part 65, a second part 66, and a third part 67. The first part 65 is located at a position in the y direction of the negative electrode 2 with a gap 7 therebetween. The second part 66 is located at a position in the y direction of the negative electrode 2 with a gap 75 therebetween. The third part 67 is located at a position in the y direction of the negative electrode 2 with a gap 76 therebetween. The second part 66 and the third part 67 sandwich the negative electrode 2 in the y direction. A part of the columnar body 6 is located at a position in the y direction of the negative electrode 2. Here, an example of the columnar body 6 in which the first part 65, the second part 66, and the third part 67 are connected is shown. However, it is also possible that the first part 65 and the second part 66 are separated, and the first part 65 and the third part 67 are separated. In the case where they are separated, the second part 66 and the third part 67 are an example of a fourth columnar body. The layer structures of the first part 65, the second part 66, and the third part 67 can be single layers respectively, or structures in which multiple layers are stacked.

[0130] The width of the first part 65 of the columnar body 6 in the x - direction is set as W1, the width of the gap 7 in the x - direction is set as W2, the width of the overlapping part of the positive electrode 1 and the negative electrode 2 when observed from the z - direction in the x - direction is set as W3, the width of the gap 5 in the x - direction is set as W4, and the width of the first part 45 of the columnar body 4 in the x - direction is set as W5. In this case, W2 / W1 preferably satisfies 0.07 ≤ W2 / W1 ≤ 15.0, and more preferably satisfies 0.14 ≤ W2 / W1 ≤ 7.0. In addition, W4 / W5 preferably satisfies 0.07 ≤ W4 / W5 ≤ 15.0, and more preferably satisfies 0.14 ≤ W4 / W5 ≤ 70. When the width of the gap in the x - direction is relatively wide with respect to the width of the columnar body in the x - direction, the stress accompanying the volume change during charge and discharge cannot be sufficiently alleviated, and the risk of generating cracks becomes high. If the width of the gap in the x - direction is relatively narrow with respect to the width of the columnar body in the x - direction, the risk of short - circuit via the columnar body becomes high.

[0131] The width of the second part 46 of the columnar body 4 in the y - direction is set as W6, the width of the gaps 55 and 75 in the y - direction is set as W7, the width of the overlapping part of the positive electrode 1 and the negative electrode 2 when observed from the z - direction in the y - direction is set as W8, the width of the gaps 56 and 76 in the y - direction is set as W9, and the width of the third part 47 of the columnar body 4 in the y - direction is set as W10. In this case, W7 / W6 preferably satisfies 0.07 ≤ W7 / W6 ≤ 15.0, and more preferably satisfies 0.14 ≤ W7 / W6 ≤ 7.0. In addition, W9 / W10 preferably satisfies 0.07 ≤ W9 / W10 ≤ 15.0, and more preferably satisfies 0.14 ≤ W9 / W10 ≤ 70. When the width of the gap in the y - direction is relatively wide with respect to the width of the columnar body in the y - direction, the stress accompanying the volume change during charge and discharge cannot be sufficiently alleviated, and the risk of generating cracks becomes high. When the width of the gap in the y - direction is relatively narrow with respect to the width of the columnar body in the y - direction, the risk of short - circuit via the columnar body becomes high.

[0132] When a part of the columnar bodies 4 and 6 is also present in the y - direction of the positive electrode 1 and the negative electrode 2, the solid electrolyte layer 3 can be three - dimensionally supported, and during pressing and firing in manufacturing, stress concentration on the solid electrolyte layer 3 can be further suppressed. In addition, by having gaps in the y - direction of the positive electrode 1 and the negative electrode 2 in the all - solid - state battery, the stress applied inside the all - solid - state battery can be further alleviated.

[0133] So far, some modification examples have been specifically shown, but the characteristic structures of each modification example can also be combined. That is, the characteristic structures of each modification example can also be combined to form other modification examples.

[0134] Examples

[0135] [Example 1]

[0136] (Fabrication of the positive electrode paste)

[0137] The positive electrode current collector layer paste is fabricated using a powder obtained by mixing Ag, Pd, and LiCoO2 in a ratio of 64:16:20 (by mass). Ethyl cellulose and dihydroterpineol are added to this powder and mixed. Ethyl cellulose serves as a binder, and dihydroterpineol serves as a solvent.

[0138] The positive electrode active material layer paste is fabricated by mixing ethyl cellulose and dihydroterpineol with LiCoO2.

[0139] (Fabrication of the solid electrolyte layer paste)

[0140] Using Li2CO3, SiO2, and Li3PO4 as starting materials, they are mixed in a molar ratio of 2:1:1. The mixing method is as follows: Using water as a dispersion medium, wet mixing is carried out using a ball mill for 16 hours. The mixture is calcined at 950 °C for 2 hours to fabricate Li 3.5 Si 0.5 P 0.5 O4. Then, 100 parts by mass of this calcined powder, 100 parts by mass of ethanol, and 200 parts by mass of toluene are added to a ball mill for wet mixing. Then, 16 parts by mass of a polyvinyl butyral binder and 4.8 parts by mass of butyl benzyl phthalate are further added and mixed to fabricate the solid electrolyte layer paste.

[0141] (Fabrication of the negative electrode paste)

[0142] The negative electrode paste is fabricated using a powder obtained by mixing Ag, Pd, and Li 3.5 Si 0.5 P 0.5 O4 in a ratio of 40:10:50 (by mass). Ethyl cellulose and dihydroterpineol are added to this powder and mixed.

[0143] (Fabrication of the all-solid-state battery)

[0144] Next, the positive electrode unit and the negative electrode unit are fabricated in the following order. First, the positive electrode active material layer paste is printed on the above-mentioned solid electrolyte layer sheet by screen printing. Next, the printed positive electrode active material layer paste is dried at 80 °C for 5 minutes. Then, the positive electrode current collector layer paste is printed on the dried positive electrode active material layer paste by screen printing. Next, the printed positive electrode current collector layer paste is dried at 80 °C for 5 minutes. Then, the positive electrode active material layer paste is printed again on the dried positive electrode current collector layer paste and dried.

[0145] Then, within the same layer as the positive electrode current collector layer paste and the positive electrode active material paste, at a position separated from the positive electrode current collector layer paste and the positive electrode active material paste in the x-direction, a solid electrolyte layer paste formed into a columnar body is printed and dried. Then, the PET film is peeled off. Thus, a positive electrode active material layer / a positive electrode current collector layer / a positive electrode active material layer are sequentially laminated on the main surface of the solid electrolyte layer, and a positive electrode unit having a columnar body is obtained, wherein the columnar body is made of the same material as the solid electrolyte layer.

[0146] In addition, in the same order, a negative electrode unit having a negative electrode laminated on the main surface of the solid electrolyte layer is obtained. The negative electrode unit has a columnar body at a position separated from the negative electrode in the x-direction, and the columnar body is made of the same material as the solid electrolyte layer. The columnar body can be produced by the following method: within the same layer as the negative electrode paste, at a position separated from the negative electrode paste in the x-direction, a solid electrolyte layer paste formed into a columnar body is printed and dried. The negative electrode in Example 1 is not divided into a negative electrode current collector layer and a negative electrode active material layer, and AgPd has the functions of both a negative electrode active material and a negative electrode current collector.

[0147] Next, the solid electrolyte layer paste was printed and dried in multiple times to fabricate a solid electrolyte unit.

[0148] Next, 10 electrode units (5 positive electrode units and 5 negative electrode units) were alternately laminated with the solid electrolyte unit interposed therebetween. At this time, the units were laminated in a staggered manner such that the odd-numbered electrode units (positive electrode units) were exposed on the first surface S1 and the even-numbered electrode units (negative electrode units) were exposed on the second surface S2. Then, 6 solid electrolyte layer sheets were laminated on the laminated units. Then, it was sandwiched between SUS plates, and after the units were bonded together by thermocompression bonding, it was cut to fabricate a laminated chip. Then, the laminated chip was fired simultaneously to obtain a laminate. During the simultaneous firing, the temperature was raised to the firing temperature of 800°C at a rate of 200°C / hour in an air atmosphere, held at this temperature for 2 hours, and then naturally cooled after firing.

[0149] In the obtained laminate, the thickness of the positive electrode is 35 μm, the thickness of the negative electrode is 35 μm, and the thickness of the solid electrolyte layer is 14 μm. In addition, the thickness of the columnar body in the same layer as the positive electrode is 35 μm, and the thickness of the columnar body in the same layer as the negative electrode is also 35 μm.

[0150] Then, a positive terminal and a negative terminal are respectively formed on the fabricated laminate (battery element). 100 samples were fabricated under the same conditions. Then, the cycle characteristics of each sample were measured. The following charge and discharge are defined as one cycle of charge and discharge of the all-solid-state battery: In an environment at 25°C, constant current charging (CC charging) is performed at a constant current rate of 0.2C until the battery voltage reaches 4.0V, and then, constant current discharge (CC discharge) is performed at a constant current rate of 0.2C until the battery voltage reaches 0V. This cycle is repeated 100 times, and the yield of samples with a capacity retention rate of 90% or more is determined. The capacity retention rate is obtained by ("capacity of the all-solid-state battery in the first cycle") / ("capacity of the all-solid-state battery in the 100th cycle") × 100.

[0151] [Examples 2 to 4]

[0152] The differences between Examples 2 to 4 and Example 1 are as follows: In Examples 2 to 4, the layer structure of at least one of the columnar bodies in the same layer as the positive electrode and the columnar bodies in the same layer as the negative electrode is different.

[0153] The difference between Example 2 and Example 1 is that in Example 2, the columnar body in the same layer as the positive electrode has the same layer structure as the positive electrode.

[0154] The difference between Example 3 and Example 1 is that in Example 3, the columnar body in the same layer as the negative electrode has the same layer structure as the negative electrode.

[0155] The difference between Example 4 and Example 1 is that in Example 4, the columnar body in the same layer as the positive electrode has the same layer structure as the positive electrode, and the columnar body in the same layer as the negative electrode has the same layer structure as the negative electrode. Other structures are the same as those in Example 1, and the yield of the sample is determined.

[0156] A columnar body with the same layer structure as the positive electrode can be fabricated by the following operation: When screen-printing the positive electrode current collector layer paste and the positive electrode active material layer paste, these pastes are also printed at the positions that will become the columnar parts. A columnar body with the same layer structure as the negative electrode can be fabricated by the following operation: When screen-printing the negative electrode paste, the negative electrode paste is also printed at the positions that will become the columnar parts.

[0157] [Examples 5 to 10]

[0158] Examples 5 to 10 are different from Example 4 in that the thickness of the solid electrolyte layer is changed. Other structures are the same as those in Example 4, and the yield of the sample is determined. The thickness of the solid electrolyte layer in each example is as follows.

[0159] Example 5: 4 μm

[0160] Example 6: 6 μm

[0161] Example 7: 8 μm

[0162] Example 8: 10 μm

[0163] Example 9: 18 μm

[0164] Example 10: 22 μm

[0165] [Examples 11 - 15]

[0166] Examples 11 - 15 are different from Example 4 in that the number of electrode units is changed when fabricating the all - solid - state battery. The other structures are the same as those in Example 4, and the yield of the samples is obtained. The total number of electrodes in the laminate for each example is as follows.

[0167] Example 11: 6 layers

[0168] Example 12: 20 layers

[0169] Example 13: 40 layers

[0170] Example 14: 80 layers

[0171] Example 15: 120 layers

[0172] [Examples 16 - 19]

[0173] Examples 16 - 19 are different from Example 4 in that the thickness of the positive electrode is changed. The other structures are the same as those in Example 4, and the yield of the samples is obtained. The thickness of the positive electrode for each example is as follows.

[0174] Example 16: 2 μm

[0175] Example 17: 5 μm

[0176] Example 18: 10 μm

[0177] Example 19: 20 μm

[0178] Example 20: 50 μm

[0179] [Examples 20 - 25]

[0180] Examples 20 - 25 are different from Example 4 in that the thickness of the negative electrode is changed. The other structures are the same as those in Example 4, and the yield of the samples is obtained. The thickness of the negative electrode for each example is as follows.

[0181] Example 20: 2 μm

[0182] Example 21: 5 μm

[0183] Example 22: 10 μm

[0184] Example 23: 20 μm

[0185] Example 24: 50 μm

[0186] [Comparative Example 1]

[0187] In Comparative Example 1, no columnar body was fabricated, which is different from Example 11 in this regard. The other structures are the same as those in Example 11, and the yield of the sample was determined.

[0188] [Comparative Examples 2 - 7]

[0189] In Comparative Examples 2 - 7, the thickness of the solid electrolyte layer was changed, which is different from Comparative Example 1 in this regard. The other structures are the same as those in Comparative Example 1, and the yield of the sample was determined. The thickness of the solid electrolyte layer in each comparative example is as follows.

[0190] Comparative Example 2: 18 μm

[0191] Comparative Example 3: 14 μm

[0192] Comparative Example 4: 10 μm

[0193] Comparative Example 5: 8 μm

[0194] Comparative Example 6: 6 μm

[0195] Comparative Example 7: 4 μm

[0196] [Comparative Examples 8 - 10]

[0197] In Comparative Examples 8 - 10, the number of electrode units when fabricating the all - solid - state battery was changed, which is different from Comparative Example 3 in this regard. The other structures are the same as those in Comparative Example 3, and the yield of the sample was determined. The total number of electrodes in the laminate in each comparative example is as follows.

[0198] Comparative Example 8: 6 layers

[0199] Comparative Example 9: 3 layers

[0200] Comparative Example 10: 2 layers

[0201] [Comparative Examples 11 - 15]

[0202] In Comparative Examples 11 - 15, the thickness of the positive electrode was changed, which is different from Comparative Example 3 in this regard. The other structures are the same as those in Comparative Example 3, and the yield of the sample was determined. The thickness of the positive electrode in each comparative example is as follows.

[0203] Comparative Example 11: 2 μm

[0204] Comparative Example 12: 5 μm

[0205] Comparative Example 13: 10 μm

[0206] Comparative Example 14: 20 μm

[0207] Comparative Example 15: 50 μm

[0208] [Comparative Examples 16 - 20]

[0209] In Comparative Examples 16 - 20, the thickness of the negative electrode was changed, which is different from Comparative Example 3 in this regard. The other structures are the same as those in Comparative Example 3, and the yield of the sample was determined. The thicknesses of the negative electrodes in each example are as follows.

[0210] Comparative Example 16: 2 μm

[0211] Comparative Example 17: 5 μm

[0212] Comparative Example 18: 10 μm

[0213] Comparative Example 19: 20 μm

[0214] Comparative Example 20: 50 μm

[0215] The results of Examples 1 - 24 and Comparative Examples 1 - 20 are summarized in Tables 1 - 4 below. In Tables 1 - 4, L1 is the thickness of the positive electrode, L2 is the thickness of the negative electrode, and L3 is the thickness of the solid electrolyte layer.

[0216]

[0217]

[0218]

[0219]

[0220] As shown in Tables 1 - 4, the yields of Examples 1 - 24 are all higher than those of Comparative Examples 1 - 20. That is, by providing columnar bodies in the same layer as the positive electrode or the negative electrode, cracks are less likely to occur inside the all - solid - state battery.

[0221] As shown in Comparative Examples 1 - 7 and Comparative Examples 11 - 20, in the absence of columnar bodies, the thicker the thickness of the positive electrode or the negative electrode relative to the thickness of the solid electrolyte layer, the lower the yield tends to be. It is considered that this is because the wider the interval between the solid electrolyte layers is when the positive electrode or the negative electrode is thicker. It is considered that when there are no columnar bodies, the solid electrolyte layer undergoes strain towards the gap between the solid electrolyte layers, and cracks are likely to occur inside the all - solid - state battery.

[0222] On the other hand, as shown in Examples 5 to 10 and Examples 16 to 25, in the case of having a columnar body, even if the thickness of the positive electrode or the negative electrode is relatively thick with respect to the thickness of the solid electrolyte layer, there is no significant difference in the yield. It is considered that this is because the columnar body supports between adjacent solid electrolyte layers, making it difficult to generate strain. That is, the thicker the thickness of the positive electrode or the negative electrode, the more effectively the columnar body functions, and cracks in the all-solid-state battery can be prevented.

[0223] In addition, as shown in Comparative Examples 8 to 10, in the case of having no columnar body, the greater the total number of the positive electrode and the negative electrode, the lower the yield tends to be. It is considered that this is because the greater the total number of the positive electrode and the negative electrode, the easier it is to generate strain at the end of the laminate. In contrast, as shown in Examples 11 to 15, by providing a columnar body, even when the total number of the laminate increases, a sufficient yield can be ensured.

[0224] (Examples 26 to 58)

[0225] The all-solid-state battery of the sixth modified example shown in Figures 10 to 13 was fabricated in Examples 26 to 58. In Examples 26 to 58, in Figure 10 and Figure 11 the parts that become the second part 46, 66 and the third part 47, 67 shown, a paste that will become a columnar body was also formed, which is different from Example 2 in this regard. Other conditions are the same as in Example 2.

[0226] In Examples 26 to 58, the columnar body in the same layer as the positive electrode has the same layer structure as the positive electrode. In Examples 26 to 57, a solid electrolyte paste was used to fabricate the columnar body in the same layer as the negative electrode. The thickness of the positive electrode was fixed at 35 μm, the thickness of the negative electrode was fixed at 35 μm, and the thickness of the solid electrolyte layer was fixed at 14 μm. In addition, the thickness of the columnar body in the same layer as the positive electrode was fixed at 35 μm, and the thickness of the columnar body in the same layer as the negative electrode was fixed at 35 μm. In addition, the total number of electrodes of the laminate was fixed at 10 layers.

[0227] In Examples 26 to 58, the following widths were changed: the width W1 in the x direction of the first part 65 of the columnar body 6; the width W2 in the x direction of the gap 7; the width W3 in the x direction of the overlapping part of the positive electrode 1 and the negative electrode 2 when viewed from the z direction; the width W4 in the x direction of the gap 5; the width W5 in the x direction of the first part 45 of the columnar body 4; the width W6 in the y direction of the second part 46 of the columnar body 4; the width W7 in the y direction of the gaps 55, 75; the width W8 in the y direction of the overlapping part of the positive electrode 1 and the negative electrode 2 when viewed from the z direction; the width W9 in the y direction of the gaps 56, 76; and the width W10 in the y direction of the third part 47 of the columnar body 4.

[0228] The results in Examples 26 to 58 are summarized in Tables 5 and 6.

[0229]

[0230]

[0231] [Description of Reference Numerals]

[0232] 1: positive electrode, 11: positive electrode current collector layer, 12: positive electrode active material layer, 1A: first positive electrode, 1B: second positive electrode, 2: negative electrode, 21: negative electrode current collector layer, 22: negative electrode active material layer, 2A: first negative electrode, 2B: second negative electrode, 3: solid electrolyte layer, 4, 6: columnar body, 5, 7: void, 5A: first void, 5B: second void, 41, 61: first layer, 42, 62: second layer, 10, 10A, 10B, 10C: laminate, 80: positive terminal, 90: negative terminal, 100: all-solid-state battery, S1: first surface, S2: second surface, S3: third surface, S4: fourth surface.

Claims

1. A all-solid-state battery, wherein, Comprising: A positive electrode; A negative electrode; A solid electrolyte layer between the positive electrode and the negative electrode; and A first columnar body, which is in a position separated from the positive electrode or the negative electrode by a gap within the same layer as the positive electrode or the negative electrode.

2. The all-solid-state battery according to claim 1, wherein, The first columnar body is separated from the positive electrode by a gap within the same layer as the positive electrode.

3. The all-solid-state battery according to claim 2, wherein, Further comprising a second columnar body, The second columnar body is separated from the negative electrode by a gap within the same layer as the negative electrode.

4. The all-solid-state battery according to claim 1, wherein, Further comprising a positive terminal and a negative terminal, The positive terminal is connected to the positive electrode on a first surface of a laminate including the positive electrode, the negative electrode, and the solid electrolyte layer, The negative terminal is connected to the negative electrode on a second surface of the laminate different from the first surface, The first columnar body is located between the positive terminal and the negative electrode, or between the negative terminal and the positive electrode.

5. The all-solid-state battery according to claim 4, wherein, The positive terminal is in contact with the first surface and a surface adjacent to the first surface, and the positive terminal is not in contact with the negative electrode.

6. The all-solid-state battery according to claim 4, wherein, The negative terminal is in contact with the second surface and a surface adjacent to the second surface, and the negative terminal is not in contact with the positive electrode.

7. The all-solid-state battery according to claim 1, wherein, The first columnar body has the same layer structure as the positive electrode or the negative electrode.

8. The all-solid-state battery according to claim 1, wherein, The thickness of the positive electrode is 2.5 times or more the thickness of the solid electrolyte layer.

9. The all-solid-state battery according to claim 1, wherein, The thickness of the negative electrode is 2.5 times or more the thickness of the solid electrolyte layer.

10. The all-solid-state battery according to claim 1, wherein, The thickness of the positive electrode is 10 μm or more.

11. The all-solid-state battery according to claim 1, wherein, The thickness of the negative electrode is 10 μm or more.

12. The all-solid-state battery according to claim 1, wherein, The positive electrode is at least one layer or more, The negative electrode is at least one layer or more, The total number of the positive electrode and the negative electrode is 3 or more.

13. The all-solid-state battery according to claim 1, wherein, The laminate including the positive electrode, the negative electrode, and the solid electrolyte layer has a first positive electrode and a second positive electrode adjacent to each other in the lamination direction, When viewed from the lamination direction of the laminate, a first gap between the first positive electrode and the columnar body within the same layer as the first positive electrode and a second gap between the second positive electrode and the columnar body within the same layer as the second positive electrode overlap at least in part.

14. The all-solid-state battery according to claim 13, wherein, When viewed from the lamination direction of the laminate, 80% or more of the first gap overlaps with the second gap.

15. The all-solid-state battery according to claim 1, wherein the laminate including the positive electrode, the negative electrode, and the solid electrolyte layer has a first negative electrode and a second negative electrode adjacent to each other in the stacking direction, when viewed in the stacking direction of the laminate, a third void between the first negative electrode and the columnar body in the same layer as the first negative electrode and a fourth void between the second negative electrode and the columnar body in the same layer as the second negative electrode overlap at least partially.

16. The all-solid-state battery according to claim 15, wherein when viewed in the stacking direction of the laminate, more than 80% of the third void overlaps with the fourth void.

17. The all-solid-state battery according to claim 1, wherein in the same layer as the positive electrode or the negative electrode, a first region including the solid electrolyte constituting the solid electrolyte layer is further provided between the positive electrode or the negative electrode and the first columnar body.

18. The all-solid-state battery according to claim 1, wherein in the same layer as the positive electrode or the negative electrode, a third columnar body is further provided between the positive electrode or the negative electrode and the first columnar body.

19. The all-solid-state battery according to claim 1, wherein when in the same layer as the positive electrode or the negative electrode, the direction from the first columnar body through the void toward the positive electrode or the negative electrode is defined as the first direction, and the direction crossing the first direction is defined as the second direction, a part of the first columnar body or a fourth columnar body is present at the position in the second direction of the positive electrode or the negative electrode.

20. The all-solid-state battery according to claim 1, wherein when in the same layer as the positive electrode or the negative electrode, the direction from the first columnar body through the void toward the positive electrode or the negative electrode is defined as the first direction, the width of the void in the first direction is 0.07 times or more and 15.0 times or less the width of the first columnar body in the first direction.

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