All-solid-state battery

Abstract

The all-solid battery (100) is provided with: a laminate (10) that is formed by sequentially stacking a positive electrode active material layer (11), a solid electrolyte layer (12), and a negative electrode active material layer (13); a positive electrode current collector (15A) and a negative electrode current collector (15B) that sandwich the laminate (10) in the stacking direction; an insulating sheet (40) that surrounds the periphery of the laminate (10) between the positive electrode current collector (15A) and the negative electrode current collector (15B); and a first adhesive sheet (50A) that adheres the insulating sheet (40) and the positive electrode current collector (15A) or the insulating sheet (40) and the negative electrode current collector (15B), a first through-hole (H50) being formed in the first adhesive sheet (50A), the laminate (10) being housed in the first through-hole (H50) when viewed in the stacking direction of the laminate (10).

Description

Technical Field

[0001] This invention relates to an all-solid-state battery.

[0002] This application claims priority based on Japanese Patent Application No. 2021-131626 filed on August 12, 2021, the contents of which are incorporated herein by reference. Background Technology

[0003] In recent years, the rapid development of electronic technology has enabled the miniaturization, lightweighting, thinning, and multifunctionality of portable electronic devices. Consequently, batteries, as the power source for these devices, have a strong desire for miniaturization, lightweighting, thinning, and improved reliability. In light of this, all-solid-state batteries using solid electrolytes, as disclosed in Patent Documents 1-3, have attracted attention.

[0004] In order to suppress short circuits, the all-solid-state battery disclosed in Patent Document 1 uses a strip-shaped insulator at the edge of the current collector foil. The current collector foil of the all-solid-state battery disclosed in Patent Document 1 is larger in shape than the solid electrolyte layer, and short circuits sometimes occur when the current collector foils come into contact with each other.

[0005] Patent Document 2 discloses an all-solid-state battery comprising a positive electrode active material layer, a solid electrolyte layer, a negative electrode active material layer, and a current collector holding them in the stacking direction. It also describes a cylindrical insulating frame disposed in close contact with the side of the current collector. This cylindrical insulating frame is used in the manufacture of the all-solid-state battery. Materials forming the positive electrode layer, negative electrode layer, and solid electrolyte layer are housed inside the cylindrical insulating frame, and the all-solid-state battery is manufactured by pressurizing them in the stacking direction. In this case, Patent Document 2 discloses that the materials of the positive electrode layer and negative electrode layer are inserted between the current collector and the insulating frame at the ends of the stacking direction, ensuring airtightness between the current collector and the insulating frame.

[0006] In the all-solid-state battery disclosed in Patent Document 3, the sides of the positive electrode layer, negative electrode layer and solid electrolyte layer are covered by a resin layer.

[0007] Existing technical documents

[0008] Patent documents

[0009] Patent Document 1: Japanese Patent Application Publication No. 2004-134116

[0010] Patent Document 2: Japanese Patent Application Publication No. 2011-159635

[0011] Patent Document 3: Japanese Patent Application Publication No. 2019-192610 Summary of the Invention

[0012] The technical problem the invention aims to solve

[0013] However, in the method of using a strip-shaped insulator at the edge of the current collector foil as disclosed in Patent Document 1, there are cases where the laminate containing the positive electrode active material layer, the solid electrolyte layer and the negative electrode active material layer is offset in the in-plane direction, or a short circuit occurs in the region closer to the laminate than the insulator.

[0014] Furthermore, in the all-solid-state batteries disclosed in Patent Documents 2 and 3, cracks sometimes occur in the laminate. Additionally, the all-solid-state batteries disclosed in Patent Documents 2 and 3 require a process of covering the entire battery with an insulating film, resulting in low production efficiency. Moreover, even in the event of minor defects, it is difficult to perform operations such as disassembly and reassembly, leading to low versatility of the all-solid-state batteries disclosed in Patent Documents 2 and 3.

[0015] The present invention was made in view of the above circumstances, and its object is to provide an all-solid-state battery that can suppress the occurrence of displacement, cracking and short circuit of the laminate, and has low internal resistance.

[0016] Means for solving technical problems

[0017] The first aspect of this invention provides an all-solid-state battery comprising:

[0018] A laminate is formed by sequentially stacking a positive electrode active material layer, a solid electrolyte layer, and a negative electrode active material layer.

[0019] Positive current collector and negative current collector, which sandwich the laminate along the stacking direction;

[0020] An insulating sheet surrounds the laminate between the positive current collector and the negative current collector; and

[0021] A first adhesive sheet bonds the insulating sheet to the positive current collector, or the insulating sheet to the negative current collector.

[0022] A first through hole is formed on the first adhesive sheet.

[0023] Viewed from the stacking direction of the laminate, the laminate is housed in the first through hole.

[0024] Invention Effects

[0025] According to the present invention, an all-solid-state battery that can suppress the occurrence of displacement, cracking and short circuit of the laminate, and has low internal resistance can be provided. Attached Figure Description

[0026] Figure 1 This is a perspective view of the all-solid-state battery according to the first embodiment of the present invention.

[0027] Figure 2 This is a cross-sectional view of the all-solid-state battery according to the first embodiment of the present invention.

[0028] Figure 3 This is a top view of the all-solid-state battery according to the first embodiment of the present invention.

[0029] Figure 4 This is a cross-sectional view of a comparative example of a solid-state battery used to illustrate the function of the present invention.

[0030] Figure 5 This is a top view of a comparative example of a solid-state battery used to illustrate the function of the present invention.

[0031] Figure 6 This is a top view of a modified example of the first embodiment of the present invention, which is an all-solid-state battery.

[0032] Figure 7 This is a top view of a modified all-solid-state battery.

[0033] Figure 8 This is a top view of a modified all-solid-state battery.

[0034] Figure 9 This is a top view of a modified all-solid-state battery.

[0035] Figure 10 It is along Figure 9 The cross-sectional view of the cut line AA.

[0036] Figure 11 This is a cross-sectional view of a modified all-solid-state battery.

[0037] Figure 12 yes Figure 11 The top view of the all-solid-state battery shown.

[0038] Figure 13 This is a cross-sectional view of a modified all-solid-state battery.

[0039] Figure 14 This is a cross-sectional view of a modified all-solid-state battery.

[0040] Figure 15 This is a cross-sectional view of a modified all-solid-state battery.

[0041] Figure 16 This is a top view of a modified all-solid-state battery.

[0042] Figure 17 yes Figure 16 The cross-sectional view of the all-solid-state battery is shown.

[0043] Figure 18 This is a top view of a modified all-solid-state battery.

[0044] Figure 19A This is a top view of a modified all-solid-state battery.

[0045] Figure 19B This is a top view of a modified all-solid-state battery.

[0046] Figure 19C This is a top view of a modified all-solid-state battery.

[0047] Figure 20 These are graphs showing the results of measuring the internal resistance of Examples 1, 2 and Comparative Example 1.

[0048] Symbol Explanation

[0049] 10...Layered bodies

[0050] 11……Positive electrode active material layer

[0051] 12……Solid electrolyte layer

[0052] 13……Negative electrode active material layer

[0053] 15A... Positive current collector

[0054] 15B... Negative current collector

[0055] 15……Current collector

[0056] 20…external body

[0057] 40……Insulating sheet

[0058] 50... Adhesive sheet

[0059] 50A... First adhesive sheet

[0060] 50B...Second adhesive sheet

[0061] 51, 52, 53... Fixing straps

[0062] 90……Electric storage components

[0063] 100… All-solid-state battery

[0064] H40……Second through hole

[0065] H50……First through hole Detailed Implementation

[0066] The present invention includes the following methods.

[0067] (1) A first aspect of the present invention provides an all-solid-state battery comprising:

[0068] A laminate is formed by sequentially stacking a positive electrode active material layer, a solid electrolyte layer, and a negative electrode active material layer.

[0069] Positive current collector and negative current collector, which sandwich the above-mentioned stacked body along the stacking direction;

[0070] An insulating sheet surrounds the laminate between the positive current collector and the negative current collector.

[0071] The first adhesive sheet bonds the insulating sheet to the positive current collector, or the insulating sheet to the negative current collector.

[0072] A first through hole is formed on the first adhesive sheet.

[0073] When viewed from the stacking direction of the aforementioned laminated body, the aforementioned laminated body is housed within the aforementioned first through hole.

[0074] (2) The all-solid-state battery according to (1) may further include a second adhesive sheet, which adhesively bonds the insulating sheet and the positive current collector, or the insulating sheet and the negative current collector, on the side opposite to the surface of the insulating sheet that is in contact with the first adhesive sheet.

[0075] (3) In the all-solid-state battery described in (1) or (2) above, the spacing between the positive current collector and the negative current collector in the region overlapping with the first adhesive sheet may be smaller than the spacing between the positive current collector and the negative current collector in the region overlapping with the laminate.

[0076] (4) In any of the above (1) to (3) solid-state batteries, a second through hole is formed on the insulating sheet, and when viewed from the stacking direction of the stacked body, the stacked body is housed in the second through hole, and the shape of the first through hole is similar to or the same as the shape of the second through hole.

[0077] (5) In any of the above-mentioned (1) to (4) solid-state batteries, a second through hole is formed on the insulating sheet, and when viewed from the stacking direction of the stacked body, the stacked body is housed in the second through hole, and the inner size of the first through hole is greater than or equal to the inner size of the second through hole.

[0078] (6) The all-solid-state battery according to any one of (1) to (5), wherein it may further include an adhesive tape having: a first portion which is in contact with the side opposite to the side where the positive current collector is in contact with the laminate; a second portion which is in contact with the side opposite to the side where the negative current collector is in contact with the laminate; and a third portion which connects the first portion and the second portion.

[0079] Hereinafter, an example of an embodiment of the present invention will be described in detail with reference to the accompanying drawings. It should be noted that, for ease of understanding of the features of the present invention, the accompanying drawings used in the following description may sometimes show enlarged portions of the features. The dimensional ratios, orientations, etc., of the constituent elements may sometimes differ from the actual dimensions.

[0080] <All-solid-state batteries>

[0081] (First Implementation)

[0082] Figure 1 This is a perspective view of the all-solid-state battery 100 of this embodiment. Figure 2 This is a cross-sectional view of the all-solid-state battery 100 of this embodiment. Figure 3 This is a top view of the all-solid-state battery 100 according to this embodiment. Furthermore, in Figure 3 For ease of explanation, the external body 20 described later will be simplified.

[0083] The all-solid-state battery 100 includes an outer casing 20 and energy storage elements 90 housed in a main space K within the outer casing 20. Figure 1 For ease of understanding, the diagram illustrates the state of the energy storage element 90 before it is housed within the outer casing 20.

[0084] In this embodiment, an orthogonal xyz coordinate system is used to describe the positional relationship of each structure. Hereinafter, the direction of the stacked body 10 is defined as the z-direction, one of the directions in the plane orthogonal to the z-direction is defined as the x-direction, and the direction orthogonal to both the z-direction and the x-direction is defined as the y-direction.

[0085] {External body}

[0086] The outer casing 20, for example, has a metal foil 22 and a resin layer 24 laminated on both sides of the metal foil 22 (see reference). Figure 2 The outer casing 20 is a metal laminate in which a metal foil 22 is coated on both sides with a polymer film (resin layer). The metal foil 22 is, for example, aluminum foil. The resin layer 24 is, for example, a polymer film such as polypropylene. The resin layer 24 can also be different on the inner and outer sides. For example, as the outer resin layer, a polymer with a high melting point, such as polyethylene terephthalate (PET) or polyamide (PA), can be used, while as the inner resin layer, a resin layer with high heat resistance, oxidation resistance, and reduction resistance, such as polyethylene (PE) or polypropylene (PP), can be used.

[0087] {Electronic Storage Components}

[0088] The energy storage element 90 includes a laminate 10, a positive current collector 15A, a negative current collector 15B, an insulating sheet 40, a first adhesive sheet 50A, and a second adhesive sheet 50B. Hereinafter, without distinguishing between the positive current collector 15A and the negative current collector 15B, it will sometimes be simply referred to as the current collector 15. Furthermore, hereafter, without distinguishing between the first adhesive sheet 50A and the second adhesive sheet 50B, it will sometimes be simply referred to as the adhesive sheet 50.

[0089] [Current Collector]

[0090] The positive current collector 15A and the negative current collector 15B extend inward in a direction intersecting the z-direction. A laminate 10 is sandwiched between the positive current collector 15A and the negative current collector 15B in the z-direction. Figure 2 and Figure 3 In the figure, W15 represents the width of the current collector 15 in the x direction, and L15 represents the length in the y direction.

[0091] The positive current collector 15A and the negative current collector 15B are, for example, made of materials with high conductivity. The positive current collector 15A and the negative current collector 15B are, for example, metals such as silver, palladium, gold, platinum, aluminum, copper, nickel, titanium, stainless steel, and their alloys or conductive resins. The positive current collector 15A and the negative current collector 15B can be made of the same material or different materials. Furthermore, in... Figure 2 and Figure 3 The example shown is where the positive current collector 15A and the negative current collector 15B are the same size, but they can also be different.

[0092] [Layered Body]

[0093] The laminate 10 is formed by sequentially stacking a positive electrode active material layer 11, a solid electrolyte layer 12, and a negative electrode active material layer 13 in the z-direction. The laminate 10 is disposed between the positive electrode current collector 15A and the negative electrode current collector 15B. The laminate 10 is housed in the second through hole H40 and the first through hole H50, described later, in the in-plane direction of the positive electrode active material layer 11.

[0094] The top view shape of the laminate 10 is, for example, circular. In this embodiment, D10 represents the outer dimension of the laminate 10 when viewed from the z direction, and T10 represents the thickness of the laminate 10 in the z direction.

[0095] The laminate 10 accepts and accepts electrons with the positive current collector 15A and the negative current collector 15B, and accepts lithium ions through the solid electrolyte layer 12. Through the acceptance and acceptance of electrons and lithium ions by the laminate 10, the all-solid-state battery 100 is charged or discharged.

[0096] (Positive electrode active material layer)

[0097] The positive electrode active material layer 11 is located on the positive electrode current collector 15A side of the solid electrolyte layer 12. The positive electrode active material layer 11 contains positive electrode active material, and may also contain conductive additives, binders, and the solid electrolyte described later, as needed.

[0098] The positive electrode active material contained in the positive electrode active material layer 11 is, for example, lithium-containing transition metal oxides, transition metal fluorides, polyanions, transition metal sulfides, transition metal oxyfluorides, transition metal oxysulfides, and transition metal oxynitrides.

[0099] There are no particular limitations on the positive electrode active material as long as it can reversibly release and adsorb lithium ions, and perform lithium ion insertion and extraction. For example, known positive electrode active materials used in lithium-ion secondary batteries can be used.

[0100] Specifically, positive electrode active materials include, for example, lithium cobalt oxide (LiCoO2), lithium nickel oxide (LiNiO2), lithium manganese spinel (LiMn2O4), and materials with the general formula: LiNi x Co y Mn z M a O2 (x+y+z+a=1, 0≤x≤1, 0≤y≤1, 0≤z≤1, 0≤a≤1, M is one or more elements selected from Al, Mg, Nb, Ti, Cu, Zn, Cr) represents composite metal oxides, lithium vanadium compounds (LiV2O5, Li3V2(PO4)3, LiVOPO4), olivine-type LiMPO4 (where M represents one or more elements selected from Co, Ni, Mn, Fe, Mg, V, Nb, Ti, Al, Zr), lithium titanate (Li4Ti5O) 12 LiNi x Co y Al z O2 (0.9 < x + y + z < 1.1) and other composite metal oxides.

[0101] Furthermore, if a negative electrode active material doped with metallic lithium or lithium ions is pre-configured in the negative electrode, a lithium-free positive electrode active material can also be used from the start of battery discharge. Examples of such positive electrode active materials include lithium-free metal oxides (MnO2, V2O5, etc.), lithium-free metal sulfides (MoS2, etc.), and lithium-free fluorides (FeF3, VF3, etc.).

[0102] (Negative electrode active material layer)

[0103] The negative electrode active material layer 13 is located on the negative electrode current collector 15B side of the solid electrolyte layer 12. The negative electrode active material layer 13 contains a negative electrode active material, and may also contain conductive additives, binders, and the solid electrolyte described later, as needed.

[0104] The negative electrode active material contained in the negative electrode active material layer 13 can be any compound that can absorb and desorb mobile ions, and negative electrode active materials used in known lithium-ion secondary batteries can be used. Examples of the negative electrode active material include alkali metal monomers, alkali metal alloys, carbon materials such as graphite (natural graphite, artificial graphite), carbon nanotubes, non-graphitizable carbon, graphitizable carbon, low-temperature calcined carbon, metals that can be alloyed with alkali metals such as aluminum, silicon, tin, germanium and alloys thereof, SiO x (0<x<2), oxides such as iron oxide, titanium oxide, tin dioxide, lithium titanate (Li4Ti5O 12 ) and other lithium metal oxides.

[0105] The conductive additive that can be contained in the positive electrode active material layer 11 and the negative electrode active material layer 13 is not particularly limited as long as it improves the electronic conductivity of the positive electrode active material layer 11 and the negative electrode active material layer 13, and known conductive additives can be used. Examples of the conductive additive include carbon-based 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 also be in various forms of powder and fiber.

[0106] (Binder)

[0107] The binder bonds the positive electrode current collector 15A and the positive electrode active material layer 11, the negative electrode current collector 15B and the negative electrode active material layer 13, the positive electrode active material layer 11, the negative electrode active material layer 13 and the solid electrolyte layer 12, various materials constituting the positive electrode active material layer 11, and various materials constituting the negative electrode active material layer 13.

[0108] The binder can be used, for example, within the range that does not impair the function of the positive electrode active material layer 11 and the negative electrode active material layer 13. The binder only needs to be capable of the aforementioned bonding; examples include fluoropolymers such as polyvinylidene fluoride (PVDF) and polytetrafluoroethylene (PTFE). Furthermore, in addition to the above, cellulose, styrene-butadiene rubber, ethylene-propylene rubber, polyimide resin, and polyamide-imide resin can also be used as binders. Additionally, conductive polymers with electronic conductivity and ionic conductivity can also be used as binders. Examples of conductive polymers with electronic conductivity include polyacetylene. In this case, the binder also functions as conductive additive particles; therefore, conductive additives may not be required. Examples of ionically conductive polymers, such as those capable of conducting lithium ions, include compounds formed by combining monomers of polymers (polyether polymers such as polyethylene oxide and polypropylene oxide, polyphosphazene, etc.) with lithium salts or lithium-based alkali metal salts such as LiClO4, LiBF4, LiPF6, LiTFSI, and LiFSI. Polymerization initiators for composite formation include, for example, photopolymerization initiators or thermal polymerization initiators suitable for the aforementioned monomers. Characteristics required for adhesives include redox resistance and good adhesion. If an adhesive is not needed, the adhesive may not be required.

[0109] The content of binder in the positive electrode active material layer 11 is not particularly limited, but from the viewpoint of reducing the resistance of the positive electrode active material layer 11, it is preferable to have 0.5 to 30% by volume. Furthermore, from the viewpoint of increasing energy density, the content of binder in the positive electrode active material layer 11 is preferably 0% by volume.

[0110] The content of binder in the negative electrode active material layer 13 is not particularly limited, but from the viewpoint of reducing the resistance of the negative electrode active material layer 13, it is preferably 0.5 to 30% by volume. Furthermore, from the viewpoint of increasing energy density, the content of binder in the negative electrode active material layer 13 is preferably 0% by volume.

[0111] (Solid electrolyte layer)

[0112] A solid electrolyte layer 12 is located between the positive electrode active material layer 11 and the negative electrode active material layer 13. The solid electrolyte layer 12 contains a solid electrolyte. A solid electrolyte is a substance (e.g., particles) capable of causing ions to move by an externally applied electric field. In addition, the solid electrolyte layer is an insulator that hinders the movement of electrons.

[0113] Solid electrolytes, for example, contain lithium. Solid electrolytes can also be halide materials, such as the composition shown in formula (1) below, or Li... 3.25Ge 0.25 P 0.75 Any type of sulfide material such as S4.

[0114] A a E b G c X d ……(1)

[0115] In formula (1), A is at least one element selected from Li and Cs, E is at least one element selected from Al, Sc, Y, Zr, Hf, and the lanthanides, and G is selected from OH, BO2, BO3, BO4, B3O6, B4O7, CO3, NO3, AlO2, SiO3, SiO4, Si2O7, Si3O9, and Si4O 11 Si6O 18 PO3, PO4, P2O7, P3O 10 X is at least one group selected from SO3, SO4, SO5, S2O3, S2O4, S2O5, S2O6, S2O7, S2O8, BF4, PF6, and BOB, and X is at least one element selected from F, Cl, Br, and I, wherein 0.5 ≤ a < 6, 0 < b < 2, 0 ≤ c ≤ 6, and 0 ≤ d ≤ 6.1.

[0116] Solid electrolytes can be any type of lithium superionic conductor (LISICON) compound or glass compound. 3.25 Ge 0.25 P 0.75 S4 and Li3PS4 are examples of lithium superionic conductor compounds. Li2S-P2S5 is an example of a glass compound. In addition, any solid electrolyte that can be used in a powder forming process can be used, and any material can be used. Solid electrolytes may also contain more than one of these compounds.

[0117] The solid electrolyte layer 12 may also contain substances other than the solid electrolyte material. For example, the solid electrolyte layer 12 may contain oxides or halides of alkali metal elements, oxides or halides of transition metal elements, etc. Additionally, the solid electrolyte layer 12 may also have a binder. The binder is the same as described above.

[0118] (Insulating sheet)

[0119] An insulating sheet 40 is disposed between the positive current collector 15A and the negative current collector 15B. The insulating sheet 40 extends inwards, surrounding the laminate 10 between the positive current collector 15A and the negative current collector 15B. The insulating sheet 40 may also be composed of at least one insulating film, with multiple insulating films overlapping to form a single unit. Alternatively, the insulating sheet 40 may be composed of multiple components divided along the in-plane direction. When the insulating sheet 40 is composed of multiple overlapping insulating films, the ends perpendicular to the lamination direction can be fixed, for example, using a tape. Figure 2 In the middle, use T 40 This indicates the thickness of the insulating sheet 40. Figure 2 and Figure 3 In the diagram, W40 represents the width of the insulating sheet 40 in the x direction, and L40 represents the length in the y direction.

[0120] The insulating sheet 40 is, for example, an insulating resin, and known insulating materials can be used. The insulating sheet 40 is preferably an easily processed insulating film. The insulating sheet 40 is, for example, composed of polyethylene terephthalate, polypropylene, polyimide, or PTFE.

[0121] The insulating sheet 40 has, for example, a second through-hole H40 extending along the z-direction internally. The number of second through-holes H40 in the insulating sheet 40 is at least one and arbitrary. A laminate 10 is housed inside the second through-hole H40.

[0122] The shape of the second through-hole H40 when viewed from above in the z-direction is any shape in which the insulating sheet 40 can house the laminate 10. The second through-hole H40 may also surround the laminate 10 when viewed from above in the z-direction. For example, the shape of the second through-hole H40 when viewed from above in the z-direction may be similar to that of the laminate 10. Hereinafter, the case where both the second through-hole H40 and the laminate 10 are circular will be used as an example.

[0123] The size of the second through-hole H40, viewed from above in the z-direction, is larger than the size of the laminate 10. That is, the inner dimension d40 of the second through-hole H40, viewed from above in the z-direction, is larger than the outer dimension D10 of the laminate 10. Therefore, the insulating sheet 40 and the laminate 10 are separately configured, with a space R between them. Figure 3 The diagram illustrates the case where the distance between the insulating sheet 40 and the laminate 10 is constant at any location, but the distance between the insulating sheet 40 and the laminate 10 can also vary depending on the location. Figure 3 In the diagram, the inner dimension d40 represents the diameter of the second through hole H40. The outer dimension D10 represents the diameter of the laminate.

[0124] The ratio d40 / D10 of the inner dimension d40 of the second through hole H40 to the outer dimension D10 of the laminate 10 is preferably greater than 100%. The inner dimension d40 of the second through hole H40 is preferably more than 1 mm larger than the outer dimension D10 of the laminate 10.

[0125] When the shapes of the second through hole H40 and the laminate are similar, it is preferable that the clearance between the parallel edges of the second through hole H40 and the edges of the laminate is constant.

[0126] When viewed from above in the z-direction, the shapes of the second through hole H40 and the laminate 10 can also have corners. The corners can be formed as right angles or as curved surfaces. When the second through hole H40 and the laminate 10 have corners, the clearance between the second through hole H40 and the laminate 10 at the corners may not be fixed.

[0127] (Adhesive sheet)

[0128] The adhesive sheet (adhesive layer) 50, for example, surrounds the laminate 10. Specifically, the adhesive sheet 50, for example, has a first through hole H50 internally for receiving the laminate 10. The adhesive sheet 50 can also be combined with multiple components divided in the in-plane direction. The adhesive sheet 50 is disposed between the insulating sheet 40 and the positive current collector 15A or between the insulating sheet 40 and the negative current collector 15B. When there are multiple adhesive sheets 50, adhesive sheets 50 can also be disposed between the insulating sheet 40 and the positive current collector 15A and between the insulating sheet 40 and the negative current collector 15B, respectively. The adhesive sheet 50 extends in the in-plane direction. Figure 2 and Figure 3 In the diagram, W50 represents the width of the adhesive sheet 50 in the x direction, and L50 represents the length in the y direction.

[0129] The adhesive sheet 50 overlaps with the insulating sheet 40 in the z-direction, bonding the insulating sheet 40 to either the positive current collector 15A or the negative current collector 15B. In the case of multiple adhesive sheets 50, each adhesive sheet 50 bonds the insulating sheet 40, the positive current collector 15A, and the insulating sheet 40 and negative current collector 15B respectively. In this embodiment, the insulating sheet 40 and the adhesive sheet 50 overlapping in the z-direction are sometimes collectively referred to as the layered structure 45.

[0130] Adhesive sheet 50, for example, uses double-sided tape, adhesive, or heat-bonded sheet.

[0131] Specific examples of double-sided tape are double-sided tapes in which the adhesive layer (adhesive part) is any one of rubber, acrylic, or silicone materials, and the substrate is any one of non-woven fabric, film, foam, cloth, or paper, or double-sided tapes without a substrate consisting only of the adhesive layer (adhesive part).

[0132] As a specific example of an adhesive used as the adhesive sheet 50, adhesives such as vinyl resins, styrene resins, rubber-based adhesives, and vinyl resin adhesives can be used.

[0133] As a specific example of the heat-adhesive sheet used as adhesive sheet 50, epoxy resin-based heat-adhesive sheets such as FB-ML80 / FB-ML4 (manufactured by Nitto Denko Corporation) can be used.

[0134] The adhesive sheet 50 can also be formed into a sheet shape independently, like tape. Alternatively, the adhesive sheet 50 can be formed into a sheet shape after curing, like an adhesive.

[0135] exist Figures 1-3 In the all-solid-state battery 100 shown, the adhesive sheet 50 has a first adhesive sheet 50A disposed between the positive electrode current collector 15A and the insulating sheet 40, and a second adhesive sheet 50B disposed between the negative electrode current collector 15B and the insulating sheet 40. The first adhesive sheet 50A adheres the main surface S40A of the insulating sheet 40 to the main surface S15A of the positive electrode current collector 15A. The second adhesive sheet 50B adheres the main surface S40B of the insulating sheet 40 to the main surface S15B of the negative electrode current collector 15B. The first adhesive sheet 50A and the second adhesive sheet 50B have substantially the same structure. In this embodiment, the structure described as a feature of the adhesive sheet 50 is a feature common to both the first adhesive sheet 50A and the second adhesive sheet 50B.

[0136] As described above, the adhesive sheet 50 serves to bond the current collector 15 and the insulating sheet 40. Therefore, the arrangement and shape of the adhesive sheet 50 correspond, for example, to the arrangement and shape of the current collector 15. That is, the outer dimensions of the adhesive sheet 50 are, for example, the same as the outer dimensions of the current collector 15. By making the outer dimensions of the adhesive sheet 50 the same as the outer dimensions of the current collector 15, the bonding area between the insulating sheet 40 and the current collector 15 can be maximized.

[0137] The thickness T50 of the adhesive sheet 50 in the lamination direction is, for example, 1 to 150 μm. In the overlapping area where the adhesive sheet 50 and the insulating sheet 40 overlap, the total thickness of all the adhesive sheets 50 and the insulating sheet 40 is expressed as the thickness T45. The ratio T45 / T10 of the total thickness T45 of the adhesive sheets 50 and the insulating sheet 40 to the thickness T10 of the laminate 10 is, for example, 20 to 100%, preferably 50 to 100%, and more preferably 65 to 95%.

[0138] The spacing between the positive current collector 15A and the negative current collector 15B depends, for example, on the thickness of the structure sandwiched between them. For instance, the region where the laminate 10 and the positive and negative current collectors 15A and 15B overlap in the z-direction is called the first region, and the region where the adhesive sheet 50 and the insulating sheet 40 overlap in the z-direction is called the second region. In this case, the spacing between the positive and negative current collectors 15A and 15B in the first region (hereinafter referred to as the first spacing) is wider than the spacing between the positive and negative current collectors 15A and 15B in the second region (hereinafter referred to as the second spacing). The ratio of the second spacing to the first spacing is the same as the ratio T45 / T10 of the total thickness T45 of the layered structure 45 in the second region to the thickness T10 of the laminate 10.

[0139] Furthermore, for example, if the total thickness T45 in the second region is smaller than the thickness T10 of the laminate 10, the second gap becomes a structure smaller than the first gap. In such a structure, for example, in the first region, the positive current collector 15A and the negative current collector 15B become recessed structures through the laminate 10. Therefore, since the total thickness T45 of the adhesive sheet 50 and the insulating sheet 40 is within this range relative to the thickness of the laminate 10, it is easy to make the laminate 10 and the current collector 15 fit tightly, easy to reduce internal resistance, and easy to suppress laminate defects.

[0140] The shape of the first through hole H50 when viewed from above in the z-direction is any shape in which the adhesive sheet 50 can accommodate the laminate 10. That is, the inner dimension d50 of the first through hole H50 is greater than or equal to the outer dimension D10 of the laminate 10. The distance between the adhesive sheet 50 and the laminate 10 in the in-plane direction can also vary depending on their position in the z-direction. In this case, the shortest distance between the adhesive sheet 50 and the laminate 10 in the in-plane direction is called the distance da. The distance da between the inner dimension d50 and the outer dimension D10 is, for example, 0 mm to 1 mm, or 0.1 mm to 1 mm, or 0.5 mm to 1 mm. The ratio of the outer dimension D10 of the laminate 10 to the inner dimension d50 of the first through hole H50, D10 / d50, is, for example, 0.9 to 1, or 0.90 to 0.97. In this way, by making the inner dimension d50 of the adhesive sheet 50 correspond to the outer dimension D10 of the laminate 10, misalignment of the laminate 10 can be easily suppressed.

[0141] The first through hole H50 is circular when viewed from above. Viewed from the z-direction, the first through hole H50 and the second through hole H40 are preferably similar in shape, having a common central axis, and more preferably identical. When the first through hole H50 and the second through hole H40 are similar in shape, the shape of the first through hole H50 is preferably larger than the shape of the second through hole H40. Furthermore, the inner dimension d50 of the first through hole H50 is preferably greater than or equal to the inner dimension d40 of the second through hole H40, and more preferably larger. In addition, the shape of the first through hole H50 matches the shape of the inner periphery of the laminate 10 surrounded by the adhesive sheet 50, and the shape of the second through hole H40 matches the shape of the inner periphery of the laminate 10 surrounded by the insulating sheet 40. Figure 3 In the diagram, the inner dimension d50 represents the diameter of the first through hole H50.

[0142] By making the inner dimension d50 of the first through hole H50 greater than the inner dimension d40 of the second through hole H40, the radially inner end of the main surface S40 (main surface S40A or main surface S40B) of the insulating sheet 40 can be bonded to the main surface S15 (main surface S15A or main surface S15B) of the current collector 15. Therefore, it is easier to suppress the intrusion of debris from the laminate 10 between the insulating sheet 40 and the current collector 15. Thus, with this structure, it is easier to suppress the decrease in aesthetics and the increase in internal resistance of the all-solid-state battery 100. Figure 2 and Figure 3 The diagram shows an example where the shape of the first through-hole H50 of the adhesive sheet 50 is the same as the shape of the second through-hole H40 of the insulating sheet 40. By setting the shape of the first through-hole H50 to be the same as the shape of the second through-hole H40, the adhesive sheet 50 used can be utilized without waste, thus reducing manufacturing costs and easily achieving the effect of bonding the current collector 15 and the insulating sheet 40.

[0143] The shapes of the first through hole H50 and the second through hole H40 when viewed from above in the z-direction can also be dissimilar. The shape of the first through hole H50 can also be any shape that surrounds the second through hole H40 when viewed from above in the z-direction. As a result, the amount of adhesive sheet 50 used can be reduced, thereby suppressing manufacturing costs and suppressing the displacement and cracking of the laminate.

[0144] The laminate 10 can also be directly bonded to the current collector 15. In this embodiment, since the adhesive sheet 50 has a first through hole H50 surrounding the laminate 10 when viewed from the z-direction, the laminate 10 can be directly bonded to the current collector 15. As a result, the internal resistance of the all-solid-state battery 100 can be easily reduced.

[0145] The adhesive sheet 50 can also be formed on the portion where the current collector 15 and the insulating sheet 40 overlap when viewed from the z-direction. This helps to suppress misalignment and cracking of the laminate. Furthermore, even when the adhesive sheet 50 is formed of an insulating sheet, for example, the conductivity of the laminate 10 and the current collector 15 can be ensured.

[0146] <Manufacturing Methods of All-Solid-State Batteries>

[0147] Next, an example of the manufacturing method of the all-solid-state battery of this embodiment will be described. The all-solid-state battery of this embodiment is manufactured by powder molding.

[0148] (The process of forming a laminate)

[0149] First, prepare a resin holder with a central through-hole, a lower punch, and an upper punch. To improve formability, a metal holder made of mold steel can be used instead of the resin holder. The diameter of the through-hole in the resin holder, as the outer dimension D10 of the laminate 10, can be set to a desired size. For example, the diameter of the through-hole in the resin holder is 10 mm, and the diameters of the lower and upper punches are, for example, 9.99 mm. Insert the lower punch below the through-hole in the resin holder, and feed powdered solid electrolyte from the opening side of the resin holder. Next, insert the upper punch on top of the fed powdered solid electrolyte, and place the press on a press for pressurization. The pressurization pressure is, for example, 5 kN (1.7 MPa). The powdered solid electrolyte, pressurized within the resin holder using the upper and lower punches, forms a solid electrolyte layer 12.

[0150] Next, the upper punch is temporarily removed, and the material of the positive electrode active material layer is introduced into the upper punch side of the solid electrolyte layer 12. Then, the upper punch is reinserted, and pressure is applied. The pressure applied is, for example, 5 kN (1.7 MPa). The material of the positive electrode active material layer becomes the positive electrode active material layer 11 through pressure application.

[0151] Next, the lower punch is temporarily removed, and the material of the negative electrode active material layer is fed into the lower punch side of the solid electrolyte layer 12. For example, the material of the negative electrode active material layer is fed onto the solid electrolyte layer 12 with the sample upside down opposite the positive electrode active material layer 11. Then, the lower punch is inserted again, and pressure is applied. The pressure applied is, for example, 5 kN (1.7 MPa). Then, as formal molding, the pressure is applied to 20 kN (7 MPa). The material of the negative electrode active material layer becomes the negative electrode active material layer 13 by applying stronger pressure after pre-molding.

[0152] Next, the laminate 10, in which the positive electrode active material layer 11, the solid electrolyte layer 12, and the negative electrode active material layer 13 are sequentially stacked, is removed from the resin holder. To remove the laminate 10 from the resin holder, for example, with the lower punch removed, the upper punch is inserted and pressure is applied. Alternatively, with the upper punch removed, the lower punch is inserted and pressure is applied. This yields the laminate 10.

[0153] (The process of forming insulating sheets and adhesive sheets)

[0154] The insulating sheet 40 and the adhesive sheet 50 are obtained, for example, by pasting double-sided tape onto an insulating film with a specified shape and forming second through holes H40 and H50.

[0155] That is, first prepare an insulating film with a specified shape.

[0156] Next, an adhesive sheet material extending in the in-plane direction is applied to the main surface of the insulating film. For example, double-sided tape can be used as the adhesive sheet material.

[0157] Next, the insulating film with double-sided adhesive tape on its main surface is pressed and cut using a molding die. The molding die is shaped to the desired second through holes H40 and H50. The molding die is positioned in the insulating film at the desired location for forming the second through holes H40 and H50. A cutting tool can be used, for example, to cut the insulating film. A pinnacle blade (Pinnacle is a registered trademark) can be used as the cutting tool. In this way, a layered structure 45 is obtained in which the first adhesive sheet 50A and the second adhesive sheet 50B are respectively provided on the main surfaces S40A and S40B of the insulating sheet 40.

[0158] (The process of forming the positive and negative current collectors)

[0159] The positive current collector 15A and the negative current collector 15B are obtained by punching the current collector material into a desired shape using, for example, a punching tool. The punching tool can be, for example, a pinnacle blade (Pinnacle is a registered trademark).

[0160] (Assembly)

[0161] First, leads 16 and 14, which serve as electrodes, are installed on the outer side of the stacking direction of the positive current collector 15A and the negative current collector 15B, respectively. Leads 16 and the positive current collector 15A, and leads 14 and the negative current collector 15B, can be joined, for example, by ultrasonic welding.

[0162] Next, the insulating sheet 40 is bonded to either the positive current collector 15A or the negative current collector 15B via the adhesive sheet 50. The following description illustrates an example of bonding the insulating sheet 40 to the positive current collector 15A via the first adhesive sheet 50A, but the insulating sheet 40 can also be bonded to the negative current collector 15B via the second adhesive sheet 50B.

[0163] Next, using tweezers or similar tools, the laminate is housed inside the second through holes H40 and H50 of the layered structure 45.

[0164] Next, the insulating sheet 40 is bonded to the negative current collector 15B via the second adhesive sheet 50B, by sandwiching the laminate 10 and the layered structure 45 between the positive current collector 15A and the negative current collector 15B.

[0165] Next, leaving only an opening in the outer casing 20, it is then heat-sealed. Alternatively, the remaining opening can be heat-sealed while simultaneously evacuating the interior of the outer casing 20. By performing heat sealing while evacuating, the outer casing 20 can be sealed with minimal gas and moisture content within the containment space K.

[0166] Next, the outer casing 20 is clamped by a metal plate via a baking plate, and the four corners of the metal plate are secured with bolts and nuts. Here, a metal plate larger than the outer casing 20 in the x or y direction can be used as the metal plate.

[0167] The all-solid-state battery 100 of this embodiment is obtained through the above processes. In the manufacturing method of the solid-state battery of this embodiment, the layered structure 45, which is composed of an insulating sheet 40 having second through holes H40 and H50 and an adhesive sheet 50, can be obtained simply by placing the adhesive sheet material extending in the in-plane direction on the insulating sheet 40 and pressing it using a molding die. Therefore, in the manufacturing method of the all-solid-state battery of this embodiment, the shape and number of the second through holes H40 and H50 can be easily adjusted by only changing the number and shape of the molding die. Therefore, in the manufacturing method of the all-solid-state battery of this embodiment, the all-solid-state battery 100 can be manufactured easily. In addition, in the manufacturing method of the all-solid-state battery of this embodiment, since the insulating sheet 40 can be easily shaped into the desired structure, it is easy to cope with the high capacity of batteries such as multilayered and large-area batteries.

[0168] Furthermore, the above is an example of manufacturing an all-solid-state battery 100 using double-sided tape as an adhesive sheet material, but the present invention is not limited to this example. For example, the manufacturing method of the all-solid-state battery of this embodiment may also use an adhesive or a thermal adhesive sheet instead of double-sided tape as the adhesive sheet material. When using an adhesive as the adhesive sheet material, for example, it is sufficient to apply the adhesive in a manner that overlaps with the main surfaces S40A and S40B of the insulating sheet 40 just before the insulating sheet 40 is to be bonded to the current collector 15. When using a thermal adhesive sheet as the adhesive sheet material, for example, it is sufficient to heat the insulating sheet 40 and the adhesive sheet 50, which house the laminate 10 within the second through holes H40 and H50, while the positive current collector 15A and the negative current collector 15B are sandwiched between them. Thus, an energy storage element 90 can be formed in which the main surface S15 of the current collector 15 and the main surface S40 of the insulating sheet 40 are bonded together via the adhesive sheet 50. In addition, an example of setting the adhesive sheet material on the insulating sheet 40 and performing a punching process has been described, but it is not limited to this example. The adhesive sheet 50 and the insulating sheet 40 can also be punched separately and then overlapped.

[0169] Additionally, an example is shown in which leads 14 and 16 are installed on the outside of the stacking direction of the positive current collector 15A and the negative current collector 15B. However, this example is not limited to the one shown. Leads 14 and 16 can also be installed on the inside of the stacking direction of the positive current collector 15A and the negative current collector 15B.

[0170] The following uses comparative examples to illustrate the function and effect of the all-solid-state battery 100 of this embodiment. Figure 4 This is a cross-sectional view of a 100r all-solid-state battery, a comparative example. Figure 5 This is a top view of the 100r all-solid-state battery.

[0171] The all-solid-state battery 100r does not have the adhesive piece 50, and the method of fixing the insulating piece 40 is different from that of the all-solid-state battery 100. For example... Figure 4 As shown, the all-solid-state battery 100r uses a fixing strap 55r to fix the surfaces of the current collector 15 away from the laminate 10 to each other, indirectly fixing the insulating sheet 40. Since the all-solid-state battery 100r does not have an adhesive sheet 50, the insulating sheet 40 cannot be fixed to the current collector 15, and sometimes a gap will be generated between the insulating sheet 40 and the current collector 15.

[0172] In the all-solid-state battery 100r, the presence of the insulating sheet 40 helps to suppress in-plane misalignment, cracks, and short circuits caused by contact between the positive current collector 15A and the negative current collector 15B of the laminate 10. However, for example, the insulating sheet 40 and the laminate 10 may sometimes be misaligned, and the ends of the laminate 10 may be damaged, for example, due to collisions. In the all-solid-state battery 100r, powder Z from the damaged laminate 10 may sometimes enter between the insulating sheet 40 and the current collector 15 from the radially inward side.

[0173] In the all-solid-state battery 100r, the energy storage element 90r is, for example, held by a metal plate via a baking plate, with the outer casing 20 clamped and secured at the four corners of the metal plate using bolts and nuts. In the energy storage element 90r, when the powder Z is located between the insulating sheet 40 and the current collector 15, the powder Z is tightly packed with the current collector 15 and the outer casing 20, reducing the aesthetics of the all-solid-state battery 100r. Furthermore, due to the powder Z, the tightness of the fit between the current collector 15 and the laminate 10 decreases, increasing the internal resistance. Additionally, if fastening is performed with the powder Z inserted between the current collector 15 and the insulating sheet 40, or between the laminate 10 and the current collector 15, excessive stress may be applied to the laminate 10, leading to cracking.

[0174] In addition, the example above shows the case where powder Z enters between the insulating sheet 40 and the current collector 15, but powder Z may also enter between the laminate 10 and the current collector 15. In such cases, the aesthetics of the all-solid-state battery 100r will be reduced and the internal resistance will increase.

[0175] In contrast, in the all-solid-state battery 100 of this embodiment, the insulating sheet 40 is bonded to the current collector 15 via the adhesive sheet 50. Therefore, the position of the insulating sheet 40 in the energy storage element 90 is fixed, making it difficult for the insulating sheet 40 and the laminate 10 to collide, thus reducing the likelihood of powder formation caused by defects in the laminate 10. Furthermore, even assuming powder formation, the seamless bonding between the insulating sheet 40 and the current collector 15 prevents powder from entering between them. Therefore, in the all-solid-state battery 100 of this embodiment, aesthetic degradation can be suppressed, and the tight bonding between the laminate 10 and the current collector 15 further suppresses the decrease in internal resistance.

[0176] Furthermore, the all-solid-state battery 100 of this embodiment can form a second through hole H40 on the insulating sheet 40 and a first through hole H50 on the adhesive sheet 50. Therefore, the insulating sheet 40 and the adhesive sheet 50 with the second through holes H40 and H50 inside can be formed by simple processing, and the all-solid-state battery 100 can be manufactured easily.

[0177] This concludes the detailed description of a specific example of the all-solid-state battery 100 according to the first embodiment. The present invention is not limited to this example, and various modifications and alterations can be made within the scope of the spirit of the invention as described in the claims. The following describes all-solid-state batteries in modified examples. In the modified all-solid-state batteries, structures identical to those in the all-solid-state battery 100 are marked with the same symbols, and descriptions are omitted.

[0178] (Variation Example 1)

[0179] Figure 6 This is a top view of the all-solid-state battery 101 of Modified Example 1. The all-solid-state battery 101 differs from the all-solid-state battery 100 in that the first through hole H50a of the adhesive sheet 50a and the second through hole H40a of the insulating sheet 40a in the laminate 10A and the energy storage element 91 are not circular.

[0180] The shapes of the first through hole H50a of the laminate 10A, the adhesive sheet 50a, and the second through hole H40a of the insulating sheet 40a are, for example, quadrilaterals. However, the shapes of the first through hole H50a of the laminate 10A, the adhesive sheet 50a, and the second through hole H40a of the insulating sheet 40a can be arbitrarily chosen, such as triangular, elliptical, or star-shaped. The shapes of the first through hole H50a of the laminate 10A, the adhesive sheet 50a, and the second through hole H40a of the insulating sheet 40a are preferably similar or identical, but they do not necessarily need to be similar or identical; any combination of shapes can be chosen.

[0181] The shapes of the laminate 10A, the first through hole H50a of the adhesive sheet 50a, and the second through hole H40a of the insulating sheet 40a can be selected according to the shape of the punching tool. Even the all-solid-state battery 101 can achieve the same effect as the all-solid-state battery 100.

[0182] (Variation Example 2)

[0183] Figure 7 This is a top view of the all-solid-state battery 102 of Modified Example 2. The difference between the all-solid-state battery 102 and the all-solid-state battery 100 is that the inner dimension d50 of the first through hole H50b of the adhesive piece 50b of the energy storage element 92 is larger than the inner dimension of the second through hole H40 of the insulating piece 40.

[0184] The ratio d50 / d40 of the inner dimension d50 of the first through hole H50 to the inner dimension d40 of the second through hole H40 is, for example, 140% or less; preferably 120% or less. The ratio d50 / d40 is preferably 100% or more; more preferably greater than 100%.

[0185] The all-solid-state battery 102 is formed, for example, by separating the process of forming a first through hole H50b on the adhesive sheet 50b and the process of forming a second through hole H40 on the insulating sheet 40.

[0186] Even in the all-solid-state battery 102, because the adhesive sheet 50b, the insulating sheet 40, and the current collector 15 are tightly bonded together, collisions between the insulating sheet 40 and the laminate 10 can be suppressed, thus preventing displacement and cracking of the laminate 10. Furthermore, even in the event of powder Z formation, because the insulating sheet 40 and the current collector 15 are bonded via the adhesive sheet 50b, the gap between the insulating sheet 40 and the current collector 15 is small even in areas where the adhesive sheet 50b is not formed, preventing powder Z from entering. In other words, it can suppress the decrease in aesthetics and the increase in internal resistance.

[0187] Because the ratio d50 / d40 is within the above range, the laminate 10 can be inserted more reliably into the second through hole H40 and the first through hole H50. If the ratio d50 / d40 is outside the above range, it may be difficult to insert the laminate into the through hole, or the adhesion between the current collector 15 and the insulating sheet 50 may be reduced.

[0188] (Variation Example 3)

[0189] Figure 8 This is a top view of the all-solid-state battery 103 of Modified Example 3. The difference between the all-solid-state battery 103 and the all-solid-state battery 100 is that the outer dimensions of the adhesive sheet 50c of the energy storage element 93 are smaller than the outer dimensions of the current collector 15.

[0190] The ratio of the outer dimension of the adhesive sheet 50c to the outer dimension of the current collector 15 is, for example, 15% to 100%, preferably 60% to 100%. By setting the outer dimension of the adhesive sheet 50c within this range, the tightness of the seal between the insulating sheet 40 and the current collector 15 can be ensured.

[0191] Even with the all-solid-state battery 103, the sealing between the radially inner insulating sheet 40 and the current collector 15 can be ensured, thus achieving the same effect as the all-solid-state battery 100.

[0192] (Variation Example 4)

[0193] Figure 9 This is a top view of the all-solid-state battery 104 in Modified Example 4. Figure 10 It is along Figure 9The image shows a cross-sectional view of the cut wire AA of the energy storage element 94. The all-solid-state battery 104 differs from the all-solid-state battery 100 in that it has multiple laminates 10 and second through holes H40 and H50 on the insulating sheet 40d and adhesive sheet 50d of the energy storage element 94. The all-solid-state battery 104, for example, has four laminates 10a, 10b, 10c, and 10d. According to this structure, the adhesive sheet 50d has first through holes H50d, H50e, H50f, and H50g that respectively house the laminates 10a, 10b, 10c, and 10d, and the insulating sheet 40 has second through holes H40d, H40e, H40f, and H40g that respectively house the laminates 10a, 10b, 10c, and 10d.

[0194] The all-solid-state battery 104 is obtained by the same manufacturing method as the all-solid-state battery 100. Even the all-solid-state battery 104 can achieve the same effect as the all-solid-state battery 100.

[0195] (Variation Example 5)

[0196] Figure 11 This is a cross-sectional view of the all-solid-state battery 105 in Modified Example 5. Figure 12 This is a top view of the all-solid-state battery 105. The difference between the all-solid-state battery 105 and the all-solid-state battery 100 is that the energy storage element 95 only has a second adhesive piece 50B and fixing strips (adhesive strips) 51, 52 and 53.

[0197] The all-solid-state battery 105 has a second adhesive sheet 50A between the insulating sheet 40 and the negative current collector 15A, but no adhesive sheet between the insulating sheet 40 and the positive current collector 15A.

[0198] The second adhesive sheet 50B bonds the insulating sheet 40 and the negative current collector 15B. In the overlapping area where the second adhesive sheet 50B and the insulating sheet 40 overlap, the total thickness T45 of the second adhesive sheet 50B (T50) and the insulating sheet 40 (T40) is, for example, less than or equal to the thickness T10 of the laminate 10. The ratio T45 / T10 of the total thickness T45 to the thickness T10 of the laminate 10 is, for example, 20% to 100%, preferably 50% to 100%, and more preferably 65% ​​to 90%. Since the ratio T45 / T10 of the total thickness T45 to the thickness T10 is within the above range, it is easy to make the laminate 10 and the current collector 15 fit together tightly.

[0199] The all-solid-state battery 105, for example, has at least one fixing band 51, 52, and 53 that fixes the surfaces of the two current collectors 15A and 15B opposite to the laminate 10 to each other and the side surface of the insulating sheet 40. The fixing bands 51, 52, and 53 are located, for example, on different sides of the current collectors 15. The fixing bands 51, 52, and 53, for example, have a first portion that contacts the surface of the positive current collector 15A opposite to the surface of the laminate 10, a second portion that contacts the surface of the negative current collector 15B opposite to the surface of the laminate 10, and a third portion that extends along the z-direction and connects the first portion and the second portion. Figure 11 The first part 51A, the second part 51B, and the third part 51C of the fixing belt 51 are shown.

[0200] In the above embodiment, an example is shown where a second adhesive piece 50B, serving as an adhesive piece 50, is provided between the negative current collector 15B and the insulating sheet 40; however, this embodiment is not limited to this example. Specifically, as... Figure 13 As shown, it can also be an all-solid-state battery 105' with a first adhesive piece 50A between the positive current collector 15A and the insulating sheet 40. When determining the orientation of the all-solid-state battery 105, it is preferable to bond the upper current collector 15 to the insulating sheet 40.

[0201] Even with all-solid-state batteries 105 and 105', the same effect as with all-solid-state battery 100 can be achieved. Furthermore, in the above embodiment, an example with three fixing strips was shown; in another embodiment, an example with fixing strips 51, 52, and 53 was shown. However, fixing strips 51, 52, and 53 may be omitted; only one fixing strip may be used; or two or more fixing strips may be used. The more fixing strips there are, the greater the stress applied to the insulating sheet 40 in the lamination direction, making it easier to fix the position of the insulating sheet 40 and easily obtain the aforementioned effect. On the other hand, even without fixing strips 51, 52, and 53, the insulating sheet 40 can be fixed by the adhesive sheet 50, thus achieving the aforementioned effect.

[0202] (Variation Example 6)

[0203] Modification 6 differs from the all-solid-state battery 100 in that it has multiple energy storage elements arranged along the stacking direction. Figure 14 and Figure 15 These are schematic cross-sectional views of the all-solid-state batteries 106 and 107 from variant example 6. Figure 14 and Figure 15 For ease of explanation, the outer casing 20 is omitted. The configuration of the all-solid-state batteries 106 and 107 in Modified Example 6, viewed from the stacking direction, is the same as that of the all-solid-state battery 100 in the first embodiment. The all-solid-state batteries 106 and 107 are examples of configurations where they are connected in series and in parallel, respectively. Figure 14 The example shown is where the thickness of the laminate 10 is the same as the thickness of the layered structure 45.

[0204] In the all-solid-state battery 106, multiple energy storage elements 90A and 90B stacked in the stacking direction are electrically connected in series, for example, via a wire L. The wire L connects, for example, the positive current collector 15A of energy storage element 90A and the negative current collector 15B of energy storage element 90B. In the all-solid-state battery 106, lead 16 is connected to the positive current collector 15A of energy storage element 90B. Lead 14 is connected to the negative current collector 15B of energy storage element 90B. The structure of energy storage elements 90A and 90B, except for leads 14 and 16, is the same as that of energy storage element 90.

[0205] In the all-solid-state battery 107, the energy storage elements 90C and 90D are arranged in reverse order of each other, with the current collectors at both ends in the z-direction having the same polarity. That is, the polarity of the current collector on the inner side in the z-direction is different from the polarity of the current collectors at both ends in the z-direction. The current collector on the inner side in the z-direction can be shared by both energy storage elements 90C and 90D, or it can be prepared independently for each energy storage element 90C and 90D and electrically connected via wires. Figure 15 In the all-solid-state battery 107 shown, lead 16 is connected to the positive current collector 15A located inside in the z-direction. Multiple leads 14 are provided and connected to current collectors located at both ends in the z-direction. That is, in Figure 15 In the middle, lead 16 is connected to the positive current collector 15A, and two leads 14 are connected to the negative current collector 15B respectively.

[0206] Even the all-solid-state battery 106 of Modified Example 6 achieves the same effect as the all-solid-state battery 100. Furthermore, experiments confirmed that because the all-solid-state battery 106 has twice the number of energy storage elements compared to the all-solid-state battery 100 connected in series, the voltage output is approximately twice as high. Additionally, experiments confirmed that because the all-solid-state battery 107 has twice the number of energy storage elements compared to the all-solid-state battery 100 connected in parallel, the battery capacity is approximately twice that of the all-solid-state battery 100, and the resistance is approximately half that of the all-solid-state battery. Moreover, the reversed energy storage elements can also be connected with… Figure 15 The example shown is the opposite.

[0207] (Variation Example 7)

[0208] Figure 16 This is a top view of the all-solid-state battery 108 of variant example 7. Figure 17 This is a schematic cross-sectional view of the all-solid-state battery 105 in Modified Example 7. For ease of explanation, in... Figure 16 The simplified representation of the outer casing 20 is in... Figure 17The outer casing 20 is omitted in the text. The all-solid-state battery 108 of Modification 7 has multiple energy storage elements 90E and 90F. In the all-solid-state battery 108, the multiple energy storage elements 90E and 90F are arranged, for example, within the same outer casing 20. The structures of the energy storage elements 90E and 90F differ from those of the energy storage element 90 only in the number of the laminate 10 and the second through-hole H40 and the first through-hole H50.

[0209] In the all-solid-state battery 108, energy storage elements 90E and 90F are connected, for example, via a wire L. The all-solid-state battery 108 is an example of energy storage elements 90E and 90F being connected in series, but they can also be connected in parallel. In the all-solid-state battery 108, lead 16 is connected to the positive current collector 15A of energy storage element 90E, and lead 14 is connected to the negative current collector 15B of energy storage element 90F.

[0210] Even the all-solid-state battery 108 of Modified Example 7 can achieve the same effect as the all-solid-state battery 100 of the first embodiment. Furthermore, in Figure 16 and Figure 17 In the all-solid-state battery 108 shown, since the two energy storage elements 90E and 90F are connected in series, the voltage output is approximately twice as high. Furthermore, in the all-solid-state battery 108, since two energy storage elements 90E and 90F are arranged in one all-solid-state battery, the battery capacity is approximately twice as high.

[0211] (Variation Example 8)

[0212] Figure 18 This is a top view schematic diagram of the all-solid-state battery 109 of Modified Example 8. The difference between the all-solid-state battery 106 and the all-solid-state battery 100 in Modified Example 8 is that it has multiple energy storage elements 90, 90 on the same surface. Figure 18 For ease of explanation, the outer casing 20 is simplified.

[0213] In the all-solid-state battery 109 of Modified Example 8, a plurality of energy storage elements 90, 90 are housed, for example, within the same housing 20. The energy storage elements 90, 90 are connected, for example, via wires L. Thus, the plurality of energy storage elements 90, 90 are electrically connected in series. In the all-solid-state battery 109, insulating seals 60 may also be provided between adjacent energy storage elements 90, 90.

[0214] Even the all-solid-state battery 109 of Modified Example 8 achieves the same effect as the all-solid-state battery 100 of the first embodiment. Furthermore, in the all-solid-state battery 109, since multiple energy storage elements 90, 90 are connected in series, the voltage output is increased compared to the all-solid-state battery 100 of the first embodiment. The increase in voltage output depends on the number of laminates 10. In such cases… Figure 18In the structure shown with two energy storage elements 90, the voltage output is twice that of the standard. Furthermore, an example is shown in the figure where an insulating seal 60 is provided and leads 16 and 14 are connected externally to the outer casing 20 via wire L. This embodiment is not limited to this example; it could also be a series structure where the seal 60 is not insulating, and adjacent energy storage elements 90, 90, have their positive current collectors 15A and negative current collectors 15B connected inside the outer casing 20.

[0215] (Variation Example 9)

[0216] Figure 19A , Figure 19B , Figure 19C This is a top view of the all-solid-state batteries 110, 111, and 112 of Variation 9. The difference between the all-solid-state batteries 110, 111, and 112 and the all-solid-state battery 100 is that the first through holes H50h, H50i, and H50j of the adhesive pieces 50h, 50i, and 50j of the energy storage elements 96, 97, and 98 are not circular.

[0217] Figure 19A The first through hole H50h in the middle is rectangular in shape. Figure 19B The first through hole H50i is rectangular in shape. Figure 19C The first through hole H50j is hexagonal in shape. In addition, the first through holes H50h, H50i, and H50j can also be arbitrarily selected as polygonal, elliptical, star-shaped, or irregular shapes.

[0218] The first through holes H50h, H50i, and H50j can also be formed in a manner that surrounds the second through hole H40 when viewed from the z-direction. When viewed from the z-direction, a portion of the first through holes H50h, H50i, and H50j may or may not be connected to the second through hole H40.

[0219] The shapes of the first through holes H50h, H50i, and H50j can be selected according to the shape of the punching tool.

[0220] All-solid-state batteries 110, 111, and 112 are formed, for example, by separating the process of forming first through holes H50h, H50i, and H50j on adhesive sheets 50h, 50i, and 50j from the process of forming second through holes H40 on insulating sheet 40.

[0221] Even in all-solid-state batteries 110, 111, and 112, the adhesive sheets 50h, 50i, and 50j, the insulating sheet 40, and the current collector 15 are tightly bonded together, thus suppressing collisions between the insulating sheet 40 and the laminate 10 and preventing displacement and cracking of the laminate 10. Furthermore, even in the event of powder Z formation, the insulating sheet 40 and the current collector 15 are bonded together via the adhesive sheets 50h, 50i, and 50j, resulting in a small gap between them even in areas where the adhesive sheets 50h, 50i, and 50j are not formed, thus suppressing the ingress of powder Z. In other words, it helps to suppress aesthetic degradation and increased internal resistance.

[0222] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the structures and combinations thereof in the above embodiments are only examples. Without departing from the spirit of the present invention, additions, omissions, substitutions and other changes to the structures can be made.

[0223] Example

[0224] The following describes embodiments of the present invention. However, the present invention is not limited to these embodiments.

[0225] [Example 1]

[0226] As an example 1, the fabrication Figure 1 The internal resistance of the all-solid-state battery shown was measured. Specifically, Example 1 was performed in the following order.

[0227] First, a laminate consisting of a positive current collector, a positive active material layer, a solid electrolyte layer, a negative active material layer, and a negative current collector was fabricated using a powder molding method according to the following method.

[0228] A 9.99mm diameter lower punch is inserted into the lower side of the through-hole of the resin holder, which has a 10mm diameter through-hole in the center. Next, Li₂ZrCl₆, forming a solid electrolyte layer, is introduced from the upper side of the through-hole. Then, a 9.99mm diameter upper punch is inserted from the upper side of the through-hole, and pressure is applied at 5kN using a press to form a 0.3mm thick solid electrolyte layer.

[0229] The upper punch was temporarily removed, and the LCO-solid electrolyte mixture, which would become the positive electrode active material layer, was introduced. The LCO-solid electrolyte mixture was prepared by mixing 0.7g of LCO, 0.35g of Li₂ZrCl₆, and 0.03g of carbon black in an agate mortar. Next, a press was used again to apply pressure at 5kN, forming a 0.05mm thick positive electrode active material layer on the solid electrolyte layer.

[0230] The lower punch was temporarily removed, and the LTO-solid electrolyte mixture, which forms the negative electrode active material layer, was introduced. The LTO-solid electrolyte mixture was prepared by mixing 0.55g, 0.4g, and 0.05g of LTO, Li₂ZrCl₆, and graphite in an agate mortar. Next, a press was used to apply pressure at 5kN, forming a 0.4mm thick laminate with a 0.05mm thick negative electrode active material layer on the underside of the positive electrode active material layer and the solid electrolyte layer.

[0231] The insulating sheet and adhesive sheet are formed by the following methods.

[0232] Specifically, first, a 100mm thick PET sheet, namely Lumirror H10 (manufactured by Toray Industries, Inc.), is prepared as the insulating film. Next, double-sided adhesive tape with a thickness of 50μm, having the same top-view shape as the insulating film, is attached to both sides of the insulating film as adhesive sheets. The double-sided adhesive tape used is (product number: HJ-9150W, manufacturer: Nitto Denko Corporation).

[0233] Next, using a pinnacle blade (Pinnacle is a registered trademark), a circular through hole with an inner diameter of 11 mm was formed in the top view center of the insulating film and double-sided tape, thus creating a layered structure 45 with adhesive sheets on the main surfaces on both sides of the insulating sheet.

[0234] To assemble energy storage components.

[0235] First, leads are ultrasonically welded to the outer side of the positive and negative current collectors in the stacking direction. Aluminum sealant tabs are used as leads.

[0236] The insulating sheet is bonded to the positive current collector using an adhesive sheet. Next, tweezers are used to arrange the laminate within the through-hole. Then, the insulating sheet is bonded to the negative current collector using an adhesive sheet.

[0237] One opening remains in the outer casing 20, which is then heat-sealed. Alternatively, the remaining opening can be heat-sealed while the interior of the outer casing 20 is evacuated. By performing heat sealing while evacuating, the outer casing 20 can be sealed with minimal gas and moisture content within the containment space K.

[0238] The outer casing 20 is held in place by a metal plate via a baking plate, and the four corners of the metal plate are secured with bolts and nuts. Here, a metal plate larger than the outer casing 20 in either the x or y direction can be used as the metal plate.

[0239] The resulting energy storage element is housed in an outer casing. An aluminum laminated bag is used as the outer casing.

[0240] (Measurement of internal resistance)

[0241] The internal resistance of the all-solid-state battery of Example 1 was measured before charging and discharging. The internal resistance was measured using a BT3563 (manufactured by Hioki Electric Co., Ltd.).

[0242] Next, using a device called the SD8 charge / discharge machine (manufactured by Hokuto Denko Co., Ltd.), the solid-state battery was charged and discharged while pressure was applied. The pressure of the solid-state battery was set to 2 kN. For charging the solid-state battery, constant current charging was performed at 0.05C until the battery voltage reached 2.8V, followed by constant voltage charging until the current density reached 0.01C. Then, for discharging, constant current discharging was performed at 0.05C until the battery voltage reached 1.3V.

[0243] The internal resistance of the all-solid-state battery after charging and discharging was measured using the same method as that used to measure the internal resistance before charging and discharging.

[0244] [Example 2]

[0245] As an example 2, a product was manufactured. Figure 11 and Figure 12 The all-solid-state battery shown is a modified version of Example 1, except that an adhesive sheet is placed only on one side between the insulating sheet and the positive current collector, and the energy storage element is fixed by a fixing strap.

[0246] As a fixing strip, 650S-25-10X20 (manufactured by Teraoka Corporation) was used. The fixing strip is disposed on three sides of the four sides of the energy storage element where there are no leads 16 and 14, and is configured to bond the main surface of the positive current collector 15A and the negative current collector 15B to the side opposite to the laminate 10 and the side of the insulating sheet 40.

[0247] For the all-solid-state battery of Example 2, the internal resistance before and after charging and discharging was measured using the same method as in Example 1.

[0248] [Comparative Example 1]

[0249] As a comparative example 1, a production was made Figure 4 and Figure 5 The all-solid-state battery shown is a modified version of Example 2, where the energy storage element is fixed only by a fixing band instead of an adhesive sheet.

[0250] For the all-solid-state battery of Comparative Example 1, the internal resistance before and after charging and discharging was measured using the same method as in Example 1.

[0251] Figure 20 The results show the measured internal resistance of the all-solid-state batteries of Examples 1, 2, and Comparative Example 1. It was confirmed that, in any state before and after charging / discharging, the all-solid-state batteries of Examples 1 and 2 had lower internal resistance than the all-solid-state battery of Comparative Example 1. This is presumably because the laminate and the current collector are tightly bonded by having adhesive sheets between the insulating sheet and the positive current collector, and between the insulating sheet and the negative current collector.

[0252] By observing the appearance of the all-solid-state batteries of Example 1, Example 2, and Comparative Example 1, it was confirmed that in the all-solid-state battery of Comparative Example 1, in the region overlapping with the current collector in the stacking direction, powder from defects in the stacked body entered between the current collector and the insulating sheet. On the other hand, in the all-solid-state batteries of Example 1 and Example 2, it was confirmed that even when observing the appearance, no unevenness caused by powder was observed, and cracks in the stacked body and powder entering between the insulating sheet and the current collector due to cracks could be suppressed.

[0253] Furthermore, in this embodiment, comparing Embodiment 1 and Embodiment 2, the result is that the internal resistance of Embodiment 2 is lower than that of Embodiment 1. However, since the all-solid-state battery of Embodiment 1 has adhesive sheets on both sides of the insulating sheet, the insulating sheet and the current collector are bonded together without gaps, and barriers are formed on both sides of the adhesive sheets, it is presumed that the powder is more difficult to enter between the insulating sheet and the current collector compared to the all-solid-state battery of Embodiment 2, and the internal resistance is easier to decrease than that of Embodiment 2.

[0254] Industrial availability

[0255] According to the present invention, an all-solid-state battery is provided that can suppress the occurrence of displacement, cracking and short circuit of the laminate, and has low internal resistance.

Claims

1. An all-solid-state battery, wherein, have: A laminate is formed by sequentially stacking a positive electrode active material layer, a solid electrolyte layer, and a negative electrode active material layer. Positive current collector and negative current collector, which sandwich the laminate along the stacking direction; An insulating sheet surrounds the laminate between the positive current collector and the negative current collector; and A first adhesive sheet bonds the insulating sheet to the positive current collector, or the insulating sheet to the negative current collector. A first through hole is formed on the first adhesive sheet. When viewed from the stacking direction of the laminate, the laminate is housed within the first through hole. A second through hole is formed on the insulating sheet. When viewed from the stacking direction of the laminate, the laminate is received in the second through hole.

2. The all-solid-state battery according to claim 1, wherein, It also has a second adhesive sheet. The second adhesive sheet bonds the insulating sheet and the positive current collector, or the insulating sheet and the negative current collector, on the side opposite to the side of the insulating sheet that is in contact with the first adhesive sheet.

3. The all-solid-state battery according to claim 1 or 2, wherein, The spacing between the positive current collector and the negative current collector in the region overlapping with the first adhesive sheet is smaller than the spacing between the positive current collector and the negative current collector in the region overlapping with the laminate.

4. The all-solid-state battery according to claim 1 or 2, wherein, The shape of the first through hole is similar to or the same as the shape of the second through hole.

5. The all-solid-state battery according to claim 1 or 2, wherein, The inner dimension of the first through hole is greater than or equal to the inner dimension of the second through hole.

6. The all-solid-state battery according to claim 1 or 2, wherein, It also has adhesive tape. The adhesive tape has the following characteristics: The first part is connected to the side opposite to the side where the positive current collector is connected to the laminate. The second part is connected to the side opposite to the surface where the negative current collector is in contact with the laminate, and The third part connects the first part and the second part.

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