All-solid-state battery and method for manufacturing all-solid-state battery

Abstract

This all-solid-state battery comprises: a base material; a first battery unit; and a second battery unit. The base material is foldable. The first battery unit and the second battery unit are separated from each other and are each layered on a first surface of the base material. Each of the first battery unit and the second battery unit includes a lower conductive layer, a first electrode, a solid electrolyte layer, a second electrode, an upper conductive layer, and an insulating layer. The lower conductive layer of the first battery unit and the lower conductive layer of the second battery unit, or the upper conductive layer of the first battery unit and the upper conductive layer of the second battery unit are connected. The first battery unit and the second battery unit can be layered by folding the base material between the first battery unit and the second battery unit.

Description

All-solid-state battery and method for manufacturing the same

[0001] This disclosure relates to an all-solid-state battery and a method for manufacturing an all-solid-state battery. This application claims priority to Japanese Patent Application No. 2024-044668, filed on March 21, 2024, the contents of which are incorporated herein by reference.

[0002] In recent years, electronics technology has made remarkable progress, leading to efforts to make portable electronic devices smaller, lighter, thinner, and more multifunctional. Accordingly, there is a strong demand for batteries that serve as the power source for electronic devices to be smaller, lighter, thinner, and more reliable, and all-solid-state batteries that use solid electrolytes have attracted attention.

[0003] All-solid-state batteries are charged and discharged by the movement of lithium ions between the positive electrode and the negative electrode via a solid electrolyte. For example, Patent Document 1 discloses an all-solid-state battery in which multiple unit cells are stacked. In Patent Document 1, the unit cells are connected to each other via contact holes or through holes.

[0004] Patent No. 3730164

[0005] When multiple single cells are stacked to form an all-solid-state battery, the formation of wiring between the cells becomes complicated, and current leakage within and between the cells can cause the all-solid-state battery to malfunction.

[0006] The present disclosure has been made in view of the above problems, and aims to provide an all-solid-state battery in which battery units can be easily stacked.

[0007] In order to solve the above problems, the following means are provided.

[0008] The all-solid-state battery according to a first aspect includes a substrate, a first battery unit, and a second battery unit. The substrate is foldable. The first battery unit and the second battery unit are spaced apart from each other and stacked on a first surface of the substrate. The first battery unit and the second battery unit each include a lower conductive layer, a first electrode, a solid electrolyte layer, a second electrode, an upper conductive layer, and an insulating layer. The lower conductive layer is stacked on the substrate. The first electrode is in contact with the lower conductive layer. The solid electrolyte layer is sandwiched between the first electrode and the second electrode. The second electrode is in contact with the upper conductive layer. The insulating layer provides insulation between the upper conductive layer and the first electrode. The lower conductive layer of the first battery unit and the lower conductive layer of the second battery unit, or the upper conductive layer of the first battery unit and the upper conductive layer of the second battery unit, are connected. The first battery unit and the second battery unit can be stacked by folding the base material between the first battery unit and the second battery unit.

[0009] A method for manufacturing an all-solid-state battery according to a second aspect includes the steps of: laminating a lower conductive layer on a substrate; forming a plurality of cells in which a first electrode, a solid electrolyte layer, and a second electrode are laminated in this order on the lower conductive layer; forming an insulating layer that exposes a portion of the second electrode of each of the cells and covers at least a portion of the interface between the first electrode and the solid electrolyte layer; forming an upper conductive layer that contacts the second electrode of at least two of the cells; and folding the substrate so that at least two of the cells overlap each other.

[0010] In the all-solid-state battery according to the above embodiment, the battery units can be easily stacked.

[0011] 1. A cross-sectional view of an all-solid-state battery according to the first embodiment. 2. An expanded perspective view of a power generating element according to the first embodiment. 3. A perspective view showing the folded structure of the power generating element according to the first embodiment. 4. A cross-sectional view of a power generating element according to the first embodiment. 5. An expanded cross-sectional view of a power generating element according to the first embodiment. 6. A cross-sectional view of a power generating element according to the third embodiment. 7. A cross-sectional view of a power generating element according to the fourth embodiment. 8. A cross-sectional view of an all-solid-state battery according to the fifth embodiment. 9. A perspective view showing the folded structure of the power generating element according to the fifth embodiment. 10. A cross-sectional view of an all-solid-state battery according to the sixth embodiment. 11. A cross-sectional view of a power generating element of an all-solid-state battery according to the seventh embodiment. 12. An expanded perspective view of a power generating element of an all-solid-state battery according to the eighth embodiment. 13. A cross-sectional view of a power generating element of an all-solid-state battery according to the eighth embodiment. 14. A perspective view showing the folded structure of the power generating element of an all-solid-state battery according to the ninth embodiment. 15. A expanded perspective view of a power generating element of an all-solid-state battery according to the tenth embodiment. 16. A cross-sectional view of a power generating element of an all-solid-state battery according to the tenth embodiment.

[0012] The present embodiment will be described in detail below with reference to the accompanying drawings. The drawings used in the following description may show characteristic portions enlarged for the sake of clarity, and the dimensional proportions of each component may differ from the actual proportions. The materials, dimensions, etc. exemplified in the following description are merely examples, and the present disclosure is not limited thereto. Appropriate modifications may be made within the scope of the present disclosure.

[0013] "First embodiment" Fig. 1 is a cross-sectional view of an all-solid-state battery 1 according to a first embodiment. The all-solid-state battery 1 includes a power generating element 100 and an exterior body 200. The exterior body 200 houses the power generating element 100. Fig. 1 shows a state immediately before the power generating element 100 is housed in the exterior body 200.

[0014] The exterior body 200 has a container 201 and a lid 202. The lid 202 has a first conductive pad 203, a second conductive pad 204, and an insulating portion 205 that provides insulation between the first conductive pad 203 and the second conductive pad 204. A first terminal T1 of the power generating element 100 is connected to the first conductive pad 203. A second terminal T2 of the power generating element 100 is connected to the second conductive pad 204. The power generating element 100 is electrically connected to the outside of the all-solid-state battery 1 via the first conductive pad 203 and the second conductive pad 204.

[0015] Fig. 2 is an exploded perspective view of the power generating element 100 according to the first embodiment. Fig. 3 is a perspective view showing the folded structure of the power generating element 100 according to the first embodiment. Fig. 4 is a cross-sectional view of the power generating element 100 according to the first embodiment after being folded.

[0016] The power generating element 100 includes a substrate B and a plurality of battery units U. The battery units U are spaced apart from one another. Each of the battery units U is stacked on a first surface of the substrate B.

[0017] One of the plurality of battery units U is a first battery unit U1, and another of the plurality of battery units U is a second battery unit U2. For example, the first battery unit U1 and the second battery unit U2 are two adjacent battery units among the plurality of battery units U, and when the power generation element 100 is folded, the first battery unit U1 and the second battery unit U2 are adjacent in the stacking direction. The first battery unit U1 and the second battery unit U2 are spaced apart from each other and are each stacked on the first surface of the base material B.

[0018] The base material B is foldable. For example, as shown in FIG. 3 , a plurality of battery units U can be stacked by folding the base material B. For example, a first battery unit U1 and a second battery unit U2 can be stacked by folding the base material B between the first battery unit U1 and the second battery unit U2. The base material B is not particularly limited. For example, the base material B is an insulating film.

[0019] In the power generating element 100, the thickness of the portion where the battery unit U is formed is greater than the thickness of the portion where no battery unit U is formed. For example, the thickness of the portion where the first battery unit U1 or the second battery unit U2 is formed is greater than the thickness of the portion where neither the first battery unit U1 nor the second battery unit U2 is formed. When this relationship is satisfied, the base material B can be easily bent in the portion where no battery unit U is formed.

[0020] Each of the multiple battery units U has a lower conductive layer 11, a cell C, an upper conductive layer 12, and an insulating layer 13. In the power generating element 100, the multiple cells C are electrically connected in parallel between the lower conductive layer 11 and the upper conductive layer 12.

[0021] The lower conductive layer 11 is laminated on the substrate B. The lower conductive layer 11 of the first battery unit U1 and the lower conductive layer 11 of the second battery unit U2 are connected and integrated. The lower conductive layer 11 is formed, for example, across multiple battery units U. The lower conductive layer 11 includes a conductive material such as Al, Ag, or Cu. For example, a first end of the lower conductive layer 11 is the second terminal T2.

[0022] The upper conductive layer 12 is stacked on the cells C. The upper conductive layer 12 of the first battery unit U1 and the upper conductive layer 12 of the second battery unit U2 are connected and integrated. The upper conductive layer 12 is formed, for example, across multiple battery units U. For example, a first end of the upper conductive layer 12 is the first terminal T1. As shown in FIG. 4 , the upper conductive layers 12 of adjacent battery units U in the stacking direction may be positioned so as to overlap in the stacking direction. Because the cells C are electrically connected in parallel, there is no problem even if the upper conductive layers 12 of adjacent battery units U in the stacking direction come into contact with each other. The upper conductive layer 12 includes a conductive material. For example, the same material as the lower conductive layer 11 can be used for the upper conductive layer 12.

[0023] 5 is an exploded cross-sectional view of the power generating element 100 according to the first embodiment. Each of the plurality of cells C includes a first electrode 21, a second electrode 22, and a solid electrolyte layer 23.

[0024] The first electrode 21 is in contact with the lower conductive layer 11. The first electrode 21 is, for example, a positive electrode. The first electrode 21 includes, for example, a positive electrode current collector 21A and a positive electrode active material layer 21B.

[0025] The positive electrode current collector 21A may be made of any electron-conductive material that is resistant to oxidation during charging and corrosion. Examples of the positive electrode current collector 21A include metals such as aluminum, stainless steel, nickel, and titanium, and conductive resins. The positive electrode current collector 21A may be in the form of powder, foil, punched, or expanded.

[0026] The positive electrode active material layer 21B includes, for example, a positive electrode active material and a conductive additive, and may also include a solid electrolyte and a binder.

[0027] The positive electrode active material is not particularly limited as long as it can reversibly absorb and release lithium ions and insert and extract them (intercalate and deintercalate), and any positive electrode active material used in known solid-state batteries can be used. Examples of the positive electrode active material include lithium-containing metal oxides and lithium-containing metal phosphates.

[0028] The lithium-containing metal oxide is, for example, lithium cobalt oxide (LiCoO ２ ), lithium nickel oxide (LiNiO ２ ), lithium manganese spinel (LiMn ２ O ４ ), and the general formula: LiNi ｘ Co ｙ Mn ｚ O ２ A composite metal oxide represented by (x + y + z = 1), a lithium vanadium compound (LiVOPO ４ , Li ３ V ２ (P.O. ４ ) ３ ), olivine-type LiMPO ４ (wherein M represents at least one selected from Co, Ni, Mn, and Fe), lithium titanate (Li ４ Ti ５ O １２ ) etc.

[0029] The positive electrode active material may not contain lithium. Examples of such a positive electrode active material include lithium-free metal oxides (MnO ２ , V ２ O ５ etc.), lithium-free metal sulfides (MoS ２ etc.), lithium-free fluorides (FeF ３ , V.F. ３ When a positive electrode active material that does not contain lithium is used, the negative electrode is doped with lithium ions in advance, or a negative electrode containing lithium ions is used.

[0030] The conductive additive improves the electronic conductivity of the positive electrode active material layer. Known conductive additives can be used. Examples of the conductive additive include carbon materials such as carbon black, graphite, carbon nanotubes, and graphene; metals such as aluminum, copper, nickel, stainless steel, iron, and amorphous metals; conductive oxides such as ITO; and mixtures thereof. The conductive additive may be in the form of powder or fiber.

[0031] The solid electrolyte contained in the positive electrode active material layer is, for example, the same as the solid electrolyte contained in the solid electrolyte layer 23. The solid electrolyte contained in the positive electrode active material layer may be different from the solid electrolyte contained in the solid electrolyte layer 23. The solid electrolyte may be any of an oxide-based solid electrolyte, a sulfide-based solid electrolyte, a complex hydride-based solid electrolyte, and a halide-based solid electrolyte.

[0032] Examples of binders include polyvinylidene fluoride (PVDF) or copolymers thereof, polytetrafluoroethylene (PTFE), polyamide (PA), polyimide (PI), polyamideimide (PAI), polybenzimidazole (PBI), polyethersulfone (PES), polyacrylic acid (PA) and copolymers thereof, metal ion crosslinked polyacrylic acid (PA) and copolymers thereof, maleic anhydride-grafted polypropylene (PP), maleic anhydride-grafted polyethylene (PE), and mixtures thereof. Among these, PTFE is particularly preferred as the binder.

[0033] The solid electrolyte layer 23 is sandwiched between the first electrode 21 and the second electrode 22. The solid electrolyte layer 23 includes a solid electrolyte. A solid electrolyte is a substance that can move ions by an externally applied electric field. The solid electrolyte layer 23 conducts lithium ions and inhibits the movement of electrons. The solid electrolyte layer 23 may be, for example, a sintered body or a compressed body, with a compressed body being preferred.

[0034] The solid electrolyte is preferably a material having low electron conductivity and high lithium ion conductivity. The solid electrolyte may be any of an oxide-based solid electrolyte, a sulfide-based solid electrolyte, a complex hydride-based solid electrolyte, and a halide-based solid electrolyte.

[0035] The solid electrolyte is, for example, Li ２ｘ Zr(SO ４ ) ｘ Cl ４ (x is 1.0 to 3.0), Li ２ ZrSO ４ I ４ , Li ２ ZrCO ３ Cl ４ , Li ２ Zr((COO) ２ ) ０．５ Cl ５ , Li ２ Zr(CH ３ COO) ０．２ Cl ５．８ , Li ２ Zr(CF ３ COO) ０．２ Cl ５．８ , Li ２ Zr(HCOO) ０．４ Cl ５．６ , Li ２ ZrBO ２ Cl ５ , Li ２ ZrBF ４ Cl ５ , Li ３ YSO ４ Cl ４ , Li ３ YCO ３ Cl ４ , Li ３ YBO ２ Cl５ , Li ３ YBF ４ Cl ５ , Li ７－ｘ P.S. ６－ｘ Cl ｘ (x is 1.0 to 1.9), Li ２ｘ ZrO ｘ Cl ４ (x is 1.0 to 7.0), xLi ２ S-(100-x)P ２ S ５ (x is 20 to 80).

[0036] The second electrode 22 is in contact with the solid electrolyte layer 23. The second electrode 22 is in contact with the upper conductive layer 12. The second electrode 22 is, for example, a negative electrode. The second electrode 22 may have a two-layer structure in which a negative electrode current collector and a negative electrode active material layer are stacked, or may have a single-layer structure in which a negative electrode current collector and a negative electrode active material are mixed.

[0037] The second electrode 22 includes, for example, a negative electrode current collector, a negative electrode active material, and a conductive additive. The second electrode 22 may also include, for example, a solid electrolyte and a binder. The conductive additive, solid electrolyte, and binder contained in the second electrode 22 may be the same as those contained in the first electrode 21.

[0038] The negative electrode current collector may be made of any material as long as it has electron conductivity, such as metals such as copper, silver, aluminum, nickel, stainless steel, and iron, or conductive resins.

[0039] The negative electrode active material is not particularly limited as long as it can reversibly absorb and release lithium ions and insert and extract lithium ions. The negative electrode active material can be any negative electrode active material used in known all-solid-state batteries. The negative electrode active material layer may contain, for example, lithium metal as the negative electrode active material, and may be any of graphite, silicon, tin, lithium titanate (Li ４ Ti ５ O １２ ) and the like.

[0040] Here, an example is shown in which the first electrode 21 is a positive electrode and the second electrode 22 is a negative electrode, but the first electrode 21 may be a negative electrode and the second electrode 22 may be a positive electrode. In each of the multiple cells C, the first electrodes 21 may all be positive electrodes, or all be negative electrodes, or there may be a mixture of cells C with negative first electrodes 21 and cells with positive first electrodes 21. The stacking order of the cells C can be freely changed depending on conditions such as the connection of the conductive layers between the multiple battery units U and whether the battery units are arranged in series or parallel.

[0041] The insulating layer 13 provides insulation between the upper conductive layer 12 and the first electrode 21. The insulating layer 13 covers at least a portion of the interface between the first electrode 21 and the solid electrolyte layer 23. The insulating layer 13 also preferably covers the interface between the second electrode 22 and the solid electrolyte layer 23. Covering these interfaces with the insulating layer 13 prevents short-circuiting between the lower conductive layer 11 and the upper conductive layer 12. The insulating layer 13 may cover the entire cell C, for example, except for the contact point between the upper conductive layer 12 and the second electrode 22.

[0042] 6 is a diagram for explaining the method for manufacturing the all-solid-state battery 1 according to the first embodiment. The method for manufacturing the all-solid-state battery 1 according to the first embodiment includes, for example, a first step S1, a second step S2, a third step S3, a fourth step S4, a fifth step S5, a sixth step S6, a seventh step S7, and an eighth step S8.

[0043] In the first step S1, a lower conductive layer 11 is laminated on one surface of the substrate B. First, the substrate B is cut to a desired length and placed on a carrier. Then, the lower conductive layer 11 is formed on the first surface of the substrate B. The lower conductive layer 11 can be produced by a known method such as screen printing, pattern printing, or patterning using photolithography.

[0044] In the second step S2, a plurality of cells C are formed on the lower conductive layer 11. Each of the plurality of cells C has a first electrode 21, a solid electrolyte layer 23, and a second electrode 22. Each of the plurality of cells C can be fabricated by a known method, such as a powder molding method or a sintering method. The plurality of cells C are formed on the lower conductive layer 11, spaced apart from one another. For example, a plurality of cells C are mounted on one lower conductive layer 11. After the plurality of cells are mounted, they are preferably heat-treated.

[0045] In the third step S3, the insulating layer 13 is formed. The insulating layer 13 is formed so as to expose a portion of the second electrode 22 of each cell C. The insulating layer 13 covers, for example, at least a portion of the interface between the first electrode 21 and the solid electrolyte layer 23. After the insulating layer 13 is formed, another heat treatment may be performed.

[0046] In a fourth step S4, the upper conductive layer 12 is formed. The upper conductive layer 12 can be formed by a known method such as screen printing, pattern printing, or patterning using photolithography. The upper conductive layer 12 is formed across at least two cells C. The upper conductive layer 12 is in contact with the second electrodes 22 of at least two cells C. After the upper conductive layer 12 is formed, another heat treatment may be performed.

[0047] In a fifth step S5, the produced laminate is cut to produce the power generating element 100. For example, a plurality of cells C arranged in a matrix are cut into columns. Cutting the laminate is not necessarily required, and the fifth step S5 does not necessarily have to be performed.

[0048] In the sixth step S6, a crease is made in the power generating element 100. For example, a crease is made in a portion of the power generating element 100 where no battery units U are formed. By making a crease, it becomes easier to fold the base material B in a later step. The sixth step S6 does not have to be performed. The crease is made in a portion of the power generating element 100 where no multiple battery units U are formed.

[0049] In a seventh step S7, the power generating element 100 is folded. The power generating element 100 is folded so that at least two cells C overlap each other in the folded stack. Furthermore, the first terminal T1 of the power generating element 100 is welded to the first conductive pad 203 of the lid 202 of the exterior body 200, and the second terminal T2 of the power generating element 100 is welded to the second conductive pad 204 of the lid 202 of the exterior body 200. Then, the power generating element 100 is housed in the exterior body 200.

[0050] In an eighth step S8, the container 201 and the lid 202 of the exterior body 200 are sealed together. The power generating element 100 is housed in the exterior body 200, and an all-solid-state battery 1 is obtained.

[0051] In the all-solid-state battery 1 according to the first embodiment, a plurality of battery units U can be stacked simply by folding the base material B, making it possible to easily stack a plurality of battery units U. Furthermore, by collectively molding a plurality of battery units U on the base material B, the power generating element 100 can be simplified.

[0052] 7 is an exploded perspective view of a power generating element 101 according to a second embodiment. The power generating element 101 differs from the power generating element 100 in the shape of the upper conductive layer 12A and the positional relationship of the multiple battery units U. In the power generating element 101, the same components as those in the power generating element 100 are denoted by the same reference numerals, and descriptions thereof will be omitted.

[0053] The upper conductive layer 12A differs from the above-described upper conductive layer 12 in that it overlaps with the lower conductive layer 11 in the stacking direction. The shapes of the upper conductive layer 12A and the lower conductive layer 11 are not important as long as electrical insulation between the upper conductive layer 12A and the lower conductive layer 11 is ensured. Forming the upper conductive layer 12A and the lower conductive layer 11 so that they overlap in the stacking direction can increase the contact area between the upper conductive layer 12A and the second electrode 22 and / or the contact area between the lower conductive layer 11 and the first electrode 21.

[0054] 7, the battery units U do not have to be arranged at equal intervals. For example, a flat portion where no battery units U are formed may be provided between the first battery unit U1 and the second battery unit U2. The flat portion may be composed of, for example, a substrate B, a lower conductive layer 11, an insulating layer 13, and an upper conductive layer 12.

[0055] In the power generating element 101 according to the second embodiment, the battery units U can be easily stacked by folding the base material B, similarly to the power generating element 100 according to the first embodiment.

[0056] 8 is an exploded perspective view of a power generating element 102 according to a third embodiment. The power generating element 102 differs from the power generating element 100 in the shape of the substrate BA. In the power generating element 102, the same components as those in the power generating element 100 are denoted by the same reference numerals, and descriptions thereof will be omitted.

[0057] The width of the base material BA is narrower than the width of the battery unit U. The base material BA is a support for the battery unit U and serves as a connection between two battery units U. As long as adjacent battery units U can be connected, the size of the base material BA is not important.

[0058] In the power generating element 102 according to the third embodiment, similarly to the power generating element 100 according to the first embodiment, the battery units U can be easily stacked by folding the base material B. Furthermore, since the width of the base material BA is narrow, the base material BA can be easily folded.

[0059] 9 is an exploded cross-sectional view of a power generating element 103 according to a fourth embodiment. The power generating element 103 differs from the power generating element 100 in that it further includes an insulating layer 30. In the power generating element 103, the same components as those in the power generating element 100 are denoted by the same reference numerals, and descriptions thereof will be omitted.

[0060] The insulating layer 30 covers the upper conductive layer 12. The insulating layer 30 may cover the entire surfaces of the plurality of cells C. The insulating layer 30 can be made of the same material as the insulating layer 13.

[0061] In the power generating element 103 according to the fourth embodiment, similar to the power generating element 100 according to the first embodiment, the battery units U can be easily stacked by folding the substrate B. Furthermore, the power generating element 103 having the insulating layer 30 is less likely to short-circuit because the lower conductive layer 11 and the upper conductive layer 12 are not exposed. Therefore, the power generating element 103 can be folded freely.

[0062] 10 is a cross-sectional view of an all-solid-state battery 2 according to a fifth embodiment. The all-solid-state battery 2 has a power generating element 104 and an exterior body 210. In the all-solid-state battery 2, the same components as those in the all-solid-state battery 1 are denoted by the same reference numerals, and description thereof will be omitted.

[0063] The exterior body 210 has a container 211 and a lid 212. A first terminal T1 of the power generating element 104 is welded to the container 211, for example. A second terminal T2 of the power generating element 104 is welded to the lid 212, for example. The container 211 and the lid 212 are each conductive and electrically connect the power generating element 104 to the outside. When the exterior body 210 is sealed, the container 211 and the lid 212 are insulated from each other.

[0064] 11 is a perspective view showing the folded structure of a power generating element 104 according to the fifth embodiment. The power generating element 104 differs from the power generating element 100 in that the first terminal T1 is located at a first end of the substrate B and the second terminal T2 is located at a second end of the substrate B.

[0065] In the power generating element 104 according to the fifth embodiment, similarly to the power generating element 100 according to the first embodiment, the battery units U can be easily stacked by folding the substrate B. Also in the all-solid-state battery 2 according to the fifth embodiment, the power generating element 104 is housed in the exterior body 210, and electrical connection with the outside can be ensured.

[0066] 12 is a cross-sectional view of an all-solid-state battery 3 according to a sixth embodiment. The all-solid-state battery 3 has a power generating element 100 and an exterior body 220. In the all-solid-state battery 3, the same components as those in the all-solid-state battery 1 are denoted by the same reference numerals, and description thereof will be omitted.

[0067] The exterior body 220 is a laminate film. The exterior body 220 has, for example, a metal foil and a resin layer laminated on each side of the metal foil. The exterior body 220 is a metal laminate film in which the metal foil is coated with the resin layer from both sides.

[0068] The metal foil may be, for example, aluminum foil or stainless steel foil. The resin layer may be, for example, a resin film such as polypropylene. The materials constituting the inner and outer resin layers may be different. For example, the outer material may be a polymer with a high melting point, such as polyethylene terephthalate (PET) or polyamide (PA), and the inner material may be polyethylene (PE) or polypropylene (PP).

[0069] The first terminal T1 and the second terminal T2 of the power generating element 100 are exposed to the outside of the exterior body 220. The first terminal T1 and the second terminal T2 exposed to the outside of the exterior body 220 ensure electrical connection between the power generating element 100 and the outside.

[0070] The all-solid-state battery 3 according to the sixth embodiment has the same effects as the all-solid-state battery 1 according to the first embodiment.

[0071] 13 is a cross-sectional view of a power generating element 105 according to a seventh embodiment. The power generating element 105 differs from the power generating element 100 in that a battery unit U is also formed on the second surface of the substrate B. In the power generating element 105, the same components as those in the power generating element 100 are denoted by the same reference numerals, and description thereof will be omitted.

[0072] The power generating element 105 has a plurality of battery units U on each of a first surface and a second surface of the substrate B. For example, one of the plurality of battery units U formed on the first surface of the substrate B is a first battery unit U1, and another of the plurality of battery units U is a second battery unit U2. Also, for example, one of the plurality of battery units U formed on the second surface of the substrate B is a third battery unit U3, and another of the plurality of battery units U is a fourth battery unit U4.

[0073] The third battery unit U3 is positioned to overlap the first battery unit U1 when viewed from the stacking direction with the power generating elements 105 unfolded. The fourth battery unit U4 is positioned to overlap the second battery unit U2 when viewed from the stacking direction with the power generating elements 105 unfolded. The third battery unit U3 and the fourth battery unit U4 are spaced apart from each other and are each stacked on the second surface of the base material B.

[0074] The configuration of each of the plurality of battery units U formed on the second surface of the base material B is the same as that of each of the plurality of battery units U formed on the first surface.

[0075] Each of the multiple battery units U has a lower conductive layer 11, cells C, an upper conductive layer 12, and an insulating layer 13. For example, the third battery unit U3 and the fourth battery unit U4 each have a lower conductive layer 11, cells C, an upper conductive layer 12, and an insulating layer 13. The lower conductive layer 11 of the third battery unit U3 and the lower conductive layer 11 of the fourth battery unit U4, or the upper conductive layer 12 of the third battery unit U3 and the upper conductive layer 12 of the fourth battery unit U4, are connected. For example, the lower conductive layer 11 of the third battery unit U3 and the lower conductive layer 11 of the fourth battery unit U4 are connected and integrated. For example, the upper conductive layer 12 of the third battery unit U3 and the upper conductive layer 12 of the fourth battery unit U4 are connected and integrated.

[0076] In the power generating element 105 according to the seventh embodiment, similar to the power generating element 100 according to the first embodiment, the battery units U can be easily stacked by folding the base material B. Furthermore, since the battery units U are formed on both sides of the base material B, the power generating element 105 has a small number of parts.

[0077] Eighth embodiment Fig. 14 is an exploded perspective view of a power generating element 106 according to the eighth embodiment. Fig. 15 is a cross-sectional view of the power generating element 106 according to the eighth embodiment after folding. The power generating element 106 differs from the power generating element 100 in the shapes of the lower conductive layer 11B and the upper conductive layer 12B. In the power generating element 106, the same components as those in the power generating element 100 are denoted by the same reference numerals, and description thereof will be omitted.

[0078] In the developed view of the power generating element 106 shown in Fig. 14, the lower conductive layer 11B and the upper conductive layer 12B have a zigzag shape. When the lower conductive layer 11B and the upper conductive layer 12B are arranged in this manner, the upper conductive layers 12B and the lower conductive layers 11B of adjacent battery units U do not overlap in the stacking direction when the power generating element 106 is folded as shown in Fig. 15. In other words, the upper conductive layers 12B of adjacent battery units U are offset from each other when viewed from the stacking direction, and the lower conductive layers 11B of adjacent battery units U are offset from each other when viewed from the stacking direction.

[0079] In the power generating element 106 according to the eighth embodiment, similarly to the power generating element 100 according to the first embodiment, the battery units U can be easily stacked by folding the substrate B. Furthermore, since the positions of the lower conductive layers 11B or the upper conductive layers 12B between adjacent battery units U are shifted, when the power generating element 106 is folded, the unevenness of the stack after folding is reduced.

[0080] 16 is an exploded perspective view of a power generating element 107 according to a ninth embodiment. The power generating element 107 differs from the power generating element 100 in the arrangement of the multiple battery units U. In the power generating element 107, the same components as those in the power generating element 100 are denoted by the same reference numerals, and descriptions thereof will be omitted.

[0081] In the power generating element 107, the plurality of battery units U are arranged in a matrix. As shown in Fig. 16, the plurality of battery units U do not need to be arranged in a row, and there are no restrictions on their arrangement. For example, in the power generating element 107 shown in Fig. 16, the battery units U in the folded column direction are electrically connected in parallel, and groups of battery units arranged in the column direction are electrically connected in series. The battery units U that make up the power generating element 107 may be electrically connected in any manner.

[0082] In the power generating element 107 according to the ninth embodiment, the battery units U can be easily stacked by folding the base material B, similarly to the power generating element 100 according to the first embodiment.

[0083] Tenth embodiment Fig. 17 is an exploded perspective view of a power generating element 108 according to the tenth embodiment. Fig. 18 is a cross-sectional view of the power generating element 108 according to the tenth embodiment after being folded. The power generating element 108 differs from the power generating element 100 in that the power generating element 108 is electrically connected in series. In the power generating element 108, the same components as those in the power generating element 100 are denoted by the same reference numerals, and description thereof will be omitted.

[0084] The power generating element 108 has a plurality of battery units U, a plurality of lower conductive layers 11D, and a plurality of upper conductive layers 12D. Each of the plurality of lower conductive layers 11D is connected across two adjacent battery units U. Each of the plurality of upper conductive layers 12D is connected across two adjacent battery units U.

[0085] The two battery units U connected with the lower conductive layer 11D are different from the two battery units U connected with the upper conductive layer 12D. For example, the lower conductive layer 11D of the first battery unit U1 is not connected to the lower conductive layer 11D of the second battery unit U2, and the upper conductive layer 12D of the first battery unit U1 is connected to the upper conductive layer 12D of the second battery unit U2. This relationship may be reversed, for example, the lower conductive layer 11D of the first battery unit U1 is connected to the lower conductive layer 11D of the second battery unit U2, and the upper conductive layer 12D of the first battery unit U1 is not connected to the upper conductive layer 12D of the second battery unit U2.

[0086] In the power generating element 108, two cells adjacent in the folding direction have different internal configurations that make up the cell C. For example, in the first battery unit U1, the first electrode 21 is a negative electrode and the second electrode 22 is a positive electrode, whereas in the second battery unit U2, the first electrode 21 is a positive electrode and the second electrode 22 is a negative electrode. In the power generating element 108, first cells in which the first electrode 21 is a negative electrode and second cells in which the first electrode 21 is a positive electrode are arranged alternately in the folding direction.

[0087] The upper conductive layer 12D connects the positive electrode of the first cell unit U1 to the negative electrode of the second cell unit U2. The lower conductive layer 11D connects the positive electrode and negative electrode of an adjacent cell unit U. As a result, the power generating elements 108 are electrically connected in series.

[0088] In the power generating element 108 according to the tenth embodiment, similarly to the power generating element 100 according to the first embodiment, the battery units U can be easily stacked by folding the substrate B. Furthermore, as shown in the power generating element 108, the battery units U can also be connected in series.

[0089] The first to tenth embodiments have been described above in detail with reference to the drawings. However, each configuration and combination thereof in the embodiments is merely an example, and additions, omissions, substitutions, and other modifications of the configurations are possible within the scope of the present invention.

[0090] For example, the characteristic configurations of the first to tenth embodiments may be combined.

[0091] For example, the configuration of the second embodiment may be applied to each of the third to tenth embodiments. Also, for example, the configuration of the third embodiment may be applied to each of the fourth to tenth embodiments. Also, for example, the configuration of the fourth embodiment may be applied to each of the fifth to tenth embodiments. Also, for example, the configuration of the fifth embodiment may be applied to each of the sixth to tenth embodiments. Also, for example, the configuration of the sixth embodiment may be applied to each of the seventh to tenth embodiments. Also, for example, the configuration of the seventh embodiment may be applied to each of the eighth to tenth embodiments. Also, for example, the configuration of the eighth embodiment may be applied to each of the ninth to tenth embodiments. Also, for example, the configuration of the ninth embodiment may be applied to the tenth embodiment.

[0092] Furthermore, the folding direction of the power generating element is not limited to one direction, and it may be folded in multiple directions.

[0093] 1, 2, 3 All-solid-state battery 11, 11B, 11D Lower conductive layer 12, 12A, 12B, 12D Upper conductive layer 13 Insulating layer 21 First electrode 21A Positive electrode current collector 21B Positive electrode active material layer 22 Second electrode 23 Solid electrolyte layer 30 Insulating layer 100, 101, 102, 103, 104, 105, 106, 107, 108 Power generating element 200, 210, 220 Exterior body 201, 211 Container 202, 212 Lid 203 First conductive pad 204 Second conductive pad 205 Insulating part B, BA Substrate C Cell S1 First step S2 Second step S3 Third step S4 Fourth step S5 Fifth step S6 Sixth step S7 Seventh step S8 Eighth step T1 First terminal T2 Second terminal U Battery unit U1 First battery unit U2 Second battery unit U3 Third battery unit U4 Fourth battery unit

Claims

1. A battery cell comprising a substrate, a first battery unit, and a second battery unit, wherein the substrate is foldable, wherein the first battery unit and the second battery unit are spaced apart and respectively stacked on a first surface of the substrate, wherein the first battery unit and the second battery unit respectively comprise a lower conductive layer, a first electrode, a solid electrolyte layer, a second electrode, an upper conductive layer, and an insulating layer, wherein the lower conductive layer is stacked on the substrate, wherein the first electrode is in contact with the lower conductive layer, wherein the solid electrolyte layer is sandwiched between the first electrode and the second electrode, wherein the second electrode is in contact with the upper conductive layer, and wherein the insulating layer insulates between the upper conductive layer and the first electrode, and wherein the lower conductive layer of the first battery unit and the lower conductive layer of the second battery unit, or the upper conductive layer of the first battery unit and the upper conductive layer of the second battery unit, are connected, the first battery unit and the second battery unit can be stacked by folding the substrate between the first battery unit and the second battery unit.

2. The all-solid-state battery according to claim 1, wherein the lower conductive layer of the first battery unit and the lower conductive layer of the second battery unit, and the upper conductive layer of the first battery unit and the upper conductive layer of the second battery unit are connected to each other, respectively.

3. The all-solid-state battery according to claim 1, wherein the insulating layer covers at least a portion of the interface between the first electrode and the solid electrolyte layer.

4. The all-solid-state battery according to claim 1, further comprising a third battery unit and a fourth battery unit, wherein the third battery unit and the fourth battery unit are each stacked on the second surface of the base material, the third battery unit being positioned to overlap the first battery unit when viewed from the stacking direction, and the fourth battery unit being positioned to overlap the second battery unit when viewed from the stacking direction, the third battery unit and the fourth battery unit each comprising the lower conductive layer, the first electrode, the solid electrolyte layer, the second electrode, the upper conductive layer, and the insulating layer, and wherein the lower conductive layer of the third battery unit and the lower conductive layer of the fourth battery unit, or the upper conductive layer of the third battery unit and the upper conductive layer of the fourth battery unit, are connected.

5. The all-solid-state battery according to claim 1, wherein the upper conductive layer of the first battery unit and the upper conductive layer of the second battery unit are positioned so as not to overlap when the base material is folded and the first battery unit and the second battery unit are stacked.

6. The all-solid-state battery according to claim 1, wherein the first battery unit and the second battery unit are electrically connected in series.

7. The all-solid-state battery according to claim 1, wherein the first battery unit and the second battery unit are electrically connected in parallel.

8. The all-solid-state battery according to claim 1, wherein the thickness of the portion where the first battery unit or the second battery unit is formed is greater than the thickness of the portion where the first battery unit or the second battery unit is not formed.

9. The all-solid-state battery according to claim 1, further comprising an exterior body, wherein the first battery unit and the second battery unit are housed in the exterior body with the base material folded and stacked, and the first battery unit and the second battery unit are electrically connected to conductive pads formed inside the exterior body.

10. The all-solid-state battery according to claim 1, further comprising an exterior body, wherein terminals electrically connected to the lower conductive layer or the upper conductive layer of the first battery unit and the second battery unit are exposed to the outside of the exterior body.

11. A method for manufacturing an all-solid-state battery, comprising: a step of laminating a lower conductive layer on a substrate; a step of forming a plurality of cells in which a first electrode, a solid electrolyte layer, and a second electrode are laminated in this order on the lower conductive layer; a step of forming an insulating layer that exposes a portion of the second electrode of each of the cells and covers at least a portion of the interface between the first electrode and the solid electrolyte layer; a step of forming an upper conductive layer that contacts the second electrode of at least two of the cells; and a step of folding the substrate so that at least two of the cells overlap each other.

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