Collector for bipolar battery and bipolar battery

Abstract

To provide a collector for a bipolar battery and a bipolar battery with the same which can improve energy density of the battery.SOLUTION: A collector 100 for a bipolar battery is given in which a first collector 11 and a second collector 12 are bonded through a conductive adhesive layer 13. A first through hole 11a is arranged in the first collector and the conductive adhesive layer is penetrated into the first through hole and / or a second through hole 12a is arranged in the second collector and the conductive adhesive layer is penetrated into the second through hole. In a bipolar battery 1, a first electrode active material layer is bonded through the conductive adhesive layer penetrated into the first through hole to the collector for the bipolar battery and / or a second electrode active material layer is bonded through the conductive adhesive layer penetrated into the second through hole to the collector for the bipolar battery.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a current collector for a bipolar battery and a bipolar battery. [Background technology]

[0002] Patent Documents 1 and 2 disclose a bipolar lithium-ion battery including a battery element including a positive electrode layer, a negative electrode layer, one or more bipolar electrode layers provided between the positive electrode layer and the negative electrode layer, and a plurality of electrolyte layers, wherein the electrolyte layers are provided between the positive electrode layer and the bipolar electrode layer and between the negative electrode layer and the bipolar electrode layer, the bipolar electrode layer includes a bipolar electrode current collector, a positive electrode active material layer provided on one surface of the bipolar electrode current collector, and a negative electrode active material layer provided on the other surface of the bipolar electrode current collector, and the bipolar electrode current collector is formed by stacking a first current collector, an adhesive resin layer having through holes, and a second current collector in this order, and the first current collector and the second current collector are bonded via the adhesive resin layer.

[0003] Patent Document 3 discloses an electrode having a metal foil with a plurality of through holes and an active material layer coated on one or both sides of the metal foil, the active material layer containing an active material made of a carbon material capable of absorbing and releasing lithium ions, and the surface roughness Rz of the active material layer being 1 μm or more and 20 μm or less.

[0004] Patent Document 4 discloses an energy storage device including a laminate including stacked bipolar electrodes and a sealing body that seals the laminate, in which the bipolar electrode has a current collector including a first main surface and a second main surface opposite the first main surface, a first active material layer provided on the first main surface, and a second active material layer provided on the second main surface, and the current collector has a first metal foil including the first main surface, a second metal foil including the second main surface and thinner than the first metal foil, and a conductive adhesive layer provided between the first metal foil and the second metal foil and adhering the first metal foil to the second metal foil, and the conductive adhesive layer is thinner than the second metal foil. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2020-109762 [Patent Document 2] Japanese Patent Application Publication No. 2017-073374 [Patent Document 3] Japanese Patent Application Laid-Open No. 2013-077734 [Patent Document 4] International Publication No. 2024 / 053312 Summary of the Invention [Problem to be solved by the invention]

[0006] There is room for improvement in bipolar batteries with regard to energy density.

[0007] An object of the present disclosure is to provide a current collector for a bipolar battery that can improve the energy density of the battery, and a bipolar battery having such a current collector for a bipolar battery. [Means for solving the problem]

[0008] The present inventors have found that the above problems can be solved by the following means. <Aspect 1> the first current collector and the second current collector are bonded together via a conductive adhesive layer, the first current collector has a first through hole, and the conductive adhesive layer extends into the first through hole; and / or a second through hole is provided in the second current collector, and the conductive adhesive layer penetrates into the second through hole; Current collector for bipolar batteries. <Aspect 2> 2. The current collector for a bipolar battery according to aspect 1, wherein the first through-holes and the second through-holes are provided. <Aspect 3> 3. The current collector for a bipolar battery according to aspect 2, wherein the first through holes and the second through holes are not provided at positions facing each other in the stacking direction. <Aspect 4> the ratio of the total area of ​​the first through holes to the total area of ​​the first current collector in the surface direction is 10% or more and 50% or less; and / or a ratio of a total area of ​​the second through holes to a total area of ​​the second current collector in a plane direction is 10% or more and 50% or less; A current collector for a bipolar battery according to any one of aspects 1 to 3. <Aspect 5> a first electrode active material layer, a bipolar battery current collector according to any one of Aspects 1 to 4, and a second electrode active material layer, in this order; the first electrode active material layer is adhered to the bipolar battery current collector by the conductive adhesive layer that has penetrated into the first through-holes, and / or the second electrode active material layer is adhered to the bipolar battery current collector by the conductive adhesive layer that has entered the second through-holes; Bipolar battery. [Effects of the Invention]

[0009] According to the present disclosure, it is possible to provide a current collector for a bipolar battery that can improve the energy density of the battery, and a bipolar battery having such a current collector for a bipolar battery. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic cross-sectional view showing an example of a current collector for a bipolar battery according to the present disclosure. [Figure 2] 2(a) and 2(b) are schematic cross-sectional views showing an example of a current collector for a bipolar battery according to the present disclosure. [Figure 3] FIG. 3 is a schematic cross-sectional view showing an example of a current collector for a bipolar battery according to the present disclosure. [Figure 4] 4(a) and (b) are schematic plan views showing an example of a current collector for a bipolar battery according to the present disclosure. [Figure 5] FIG. 5 is a schematic cross-sectional view showing an example of a bipolar battery according to the present disclosure. [Figure 6] FIG. 6 is a schematic cross-sectional view showing an example of a current collector for a bipolar battery according to the prior art. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the present disclosure will be described in detail. Note that the present disclosure is not limited to the following embodiments, and various modifications can be made within the scope of the present disclosure.

[0012] <Current collector for bipolar batteries> In the current collector for a bipolar battery of the present disclosure, a first current collector and a second current collector are bonded together via a conductive adhesive layer, a first through hole is provided in the first current collector, and the conductive adhesive layer extends into the first through hole, and / or a second through hole is provided in the second current collector, and the conductive adhesive layer extends into the second through hole.

[0013] In a bipolar battery, in order to bond the electrode active material layer and the current collector, it is conceivable to provide an outer conductive adhesive layer 24 on the outside of a first current collector 21 and a second current collector 22, as exemplified in Fig. 6. However, in this case, the thickness of the battery increases by the amount of the outer conductive adhesive layer 24, resulting in a decrease in energy density.

[0014] The present inventors have found that by providing through holes in one or both of the first and second current collectors and having a conductive adhesive layer interposed between the first and second current collectors that penetrates into the through holes, the conductive adhesive layer that penetrates into at least one of the through holes can adhere an electrode active material layer to the bipolar battery current collector, thereby reducing the thickness of the bipolar battery compared to when an outer conductive adhesive layer is provided between the first and second current collectors and the electrode active material layer, and therefore improving the energy density of the battery.

[0015] Furthermore, in a battery using the bipolar battery current collector of the present disclosure, the current collector and the electrode active material layer are in direct contact with each other, and therefore it is believed that the resistance at the interface between the current collector and the electrode active material layer can be reduced compared to when an outer conductive adhesive layer is provided between the current collector and the electrode active material layer.

[0016] Hereinafter, elements constituting the current collector for a bipolar battery of the present disclosure will be described with reference to the drawings. Note that the dimensional relationships in the drawings do not reflect the actual dimensional relationships.

[0017] <First current collector and second current collector> As illustrated in FIGS. 1 to 3, a first current collector 11 and a second current collector 12 are bonded together via a conductive adhesive layer 13, and function as current collectors for a bipolar battery.

[0018] The first and second current collectors are not particularly limited. For example, when a battery using the bipolar battery current collector of the present disclosure is a lithium-ion secondary battery, the first and second current collectors may be copper foil, copper alloy foil, nickel foil, aluminum foil, aluminum alloy foil, stainless steel foil, carbon sheet, or the like. In particular, the first current collector and the second current collector may be different. That is, for example, when a negative electrode active material layer as the first electrode active material layer and a positive electrode active material layer as the second electrode active material layer are disposed on the surfaces of the first current collector and the second current collector opposite to the surfaces bonded by the conductive adhesive layer, the first current collector may be copper foil, and the second current collector may be aluminum foil.

[0019] A carbon coating layer may be formed on the surface of the first and second current collectors that is bonded by the conductive adhesive layer.

[0020] The thickness of the first and second current collectors is not particularly limited, but may be, for example, 10 μm or more and 150 μm or less.

[0021] The size of the first and second current collectors is not particularly limited as long as they are large enough to provide first and second through holes, which will be described later.

[0022] <Conductive adhesive layer> 1 to 3, the conductive adhesive layer 13 is interposed between the first current collector 11 and the second current collector 12, and bonds the first current collector 11 and the second current collector 12. The first and second current collectors bonded in this manner function as current collectors for the bipolar battery.

[0023] The conductive adhesive layer 13 penetrates into the first through holes 11a and the second through holes 12a, which will be described later, and thereby allows the electrode active material layer to be adhered to the bipolar battery current collector 100 without providing an outer conductive adhesive layer between at least one of the first current collector and the electrode active material layer and the second current collector and the electrode active material layer.

[0024] The material of the conductive adhesive layer is not particularly limited. For example, the conductive adhesive layer may be composed of a mixture of an adhesive component and a conductive component.

[0025] The adhesive component is not particularly limited, but examples thereof include curable resins. Examples of curable resins include thermosetting resins and photocurable resins. More specifically, examples of curable resins include olefin-based resins and acrylic-based resins.

[0026] The curable resin can be used in combination with a curing agent. The curing agent is not particularly limited, and any curing agent commonly used for curable resins can be used. Examples of the curing agent include isocyanate-based curing agents and epoxy-based curing agents.

[0027] The conductive component is not particularly limited as long as it has a higher conductivity than the adhesive component, and examples thereof include metal particles such as gold, silver, platinum, zinc, stainless steel, nickel, copper, cobalt, molybdenum, antimony, iron, and chromium; alloy particles such as aluminum-magnesium alloys and aluminum-nickel alloys; metal oxide particles such as tin oxide and indium oxide; particles in which metal particles such as nickel are coated with precious metals such as gold, silver, and platinum; non-conductive particles such as glass, ceramic, and plastic are coated with precious metals such as gold, silver, and platinum; graphites such as natural graphite and artificial graphite; and carbon particles such as carbon blacks such as acetylene black, ketjen black, channel black, furnace black, lamp black, and thermal black.

[0028] The thickness of the conductive adhesive layer is not particularly limited, but may be, for example, 10 μm or more and 150 μm or less.

[0029] The size of the conductive adhesive layer is not particularly limited, but may be the same as the size of the first and second current collectors from the viewpoint of adhesiveness to the first and second current collectors.

[0030] <First through hole and second through hole> 1 to 3, in the current collector 100 for a bipolar battery of the present disclosure, the first current collector 11 has first through holes 11a, and / or the second current collector 11 has second through holes 12a. That is, in the current collector for a bipolar battery of the present disclosure, the first through holes 11a and the second through holes 12a may be provided as follows: The first current collector 11 has first through-holes 11a, and the second current collector 12 has second through-holes 12a (see FIGS. 1 and 3); The first current collector 11 has a first through-hole 11a, but the second current collector 12 does not have a second through-hole 12a (see FIG. 2(a)); The first current collector 11 does not have a first through-hole 11a, and the second current collector 12 has a second through-hole 12a (see FIG. 2(b)).

[0031] 1 and 3, the current collector for a bipolar battery according to the present disclosure may have first and second through holes. That is, through holes may be provided in both the first current collector and the second current collector. This configuration eliminates the need for an outer conductive adhesive layer between the first current collector and the electrode active material layer and between the second current collector and the electrode active material layer, thereby more effectively improving the energy density.

[0032] As illustrated in Figures 1 and 3, in the bipolar battery current collector 100 of the present disclosure, the first through holes 11a and the second through holes 12a may be located opposite each other in the stacking direction (see Figure 1), or may not be located opposite each other (see Figure 3). When the first through holes 11a and the second through holes 12a are not located opposite each other in the stacking direction, unevenness in the internal resistance of the battery due to differences in the thickness of the conductive adhesive layer 13 can be reduced, and as a result, uneven battery reactions can be suppressed. Note that "not located opposite each other" means that the first through holes 11a and the second through holes 12a do not overlap each other in the stacking direction.

[0033] In the bipolar battery current collector 100 of the present disclosure, the ratio of the total area of ​​the first through holes 11a to the total area of ​​the first current collector 11 in the plane direction may be 10% or more and 50% or less, and / or the ratio of the total area of ​​the second through holes 12a to the total area of ​​the second current collector 12 in the plane direction may be 10% or more and 50% or less. By adopting such a configuration, an appropriate number of through holes are formed, and the current collecting function of the current collector provided with the through holes is ensured, while the electrode active material layer and the conductive adhesive layer can be well bonded to each other.

[0034] 2(a) and 2(b), when either the first through holes 11a or the second through holes 12a are provided, an outer conductive adhesive layer 14 may be provided on the current collector on the side where no through holes are provided, thereby making it possible to bond the current collector and the electrode active material layer even on the side where no through holes are provided.

[0035] 4(a) and 4(b) are schematic plan views of the bipolar battery current collector 100 of the present disclosure in FIGS. 1, 2(b), and 3, viewed from the side of the second current collector 12. From the viewpoint of reducing unevenness in the internal resistance of the battery, the second through holes 12a may be arranged with minimal deviation in the planar direction of the second current collector 12, as illustrated in FIGS. 4(a) and 4(b). Specifically, the evenly spaced second through holes 12a may extend in the planar direction (see FIG. 4(a)), or may not extend in the planar direction (see FIG. 4(b)). The planar shape of the second through holes 12a is not limited to that illustrated in FIG. 4, as long as the conductive adhesive layer 13 can bond an electrode active material layer, i.e., the conductive adhesive layer 13 can penetrate into the second through holes 12a.

[0036] Although not shown, the first through-hole 11a may also have a planar shape similar to that of the second through-hole 12a.

[0037] When both the first and second current collectors have through holes, the current collector for a bipolar battery of the present disclosure can be produced by, for example, a dry lamination method as shown below: Applying a curable resin onto the first current collector (or the second current collector) and drying it; The first current collector (or the second current collector) is half-cut into a desired shape; collecting unnecessary portions of the half-cut first current collector (or second current collector) to form first through holes (or second through holes); The second current collector (or the first current collector) in which through holes have been formed in advance is attached to the curable resin by thermocompression bonding using a heated roller or the like.

[0038] Bipolar battery 5, the bipolar battery 1 of the present disclosure includes, in this order, a first electrode active material layer 110, a bipolar battery current collector 100 of the present disclosure, and a second electrode active material layer 120. In the bipolar battery 1 of the present disclosure, the first electrode active material layer 110 is adhered to the bipolar battery current collector 100 by a conductive adhesive layer 13 that penetrates into the first through-holes 11a, and / or the second electrode active material layer 120 is adhered to the bipolar battery current collector 100 by a conductive adhesive layer 13 that penetrates into the second through-holes 12a. In such a bipolar battery, there is no need to provide an outer conductive adhesive layer for adhering at least one of the electrode active material layers, and the energy density of the battery can be improved.

[0039] In particular, in the bipolar battery 1 of the present disclosure, the first electrode active material layer 110 may be adhered to the bipolar battery current collector 100 by the conductive adhesive layer 13 that has entered the first through-holes 11a, and the second electrode active material layer 120 may be adhered to the bipolar battery current collector 100 by the conductive adhesive layer 13 that has entered the second through-holes 12a. In such a bipolar battery, there is no need to provide an outer conductive adhesive layer for adhering both electrode active material layers, and the energy density of the battery can be improved more effectively.

[0040] In the present disclosure, a laminate composed of the first electrode active material layer 110, the bipolar battery current collector 100 of the present disclosure, and the second electrode active material layer 120 may be referred to as a "bipolar electrode."

[0041] The bipolar battery 1 of the present disclosure may further include an electrolyte layer 130 in addition to the bipolar electrodes.

[0042] The bipolar battery 1 of the present disclosure may be configured by stacking multiple bipolar electrodes and electrolyte layers 130. Note that, although Fig. 5 illustrates a bipolar battery 1 configured with two bipolar electrodes and one electrolyte layer 130, the number of bipolar electrodes and electrolyte layers 130 is not limited to this.

[0043] The bipolar battery of the present disclosure may be a secondary battery, and in particular a lithium-ion secondary battery.

[0044] The bipolar battery of the present disclosure may be a liquid-based battery or a solid-state battery. In the context of the present disclosure, a "solid-state battery" refers to a battery that uses at least a solid electrolyte as an electrolyte. Therefore, a solid-state battery may use a combination of a solid electrolyte and a liquid electrolyte as an electrolyte. Alternatively, the solid-state battery of the present disclosure may be an all-solid-state battery, i.e., a battery that uses only a solid electrolyte as an electrolyte.

[0045] The elements that make up the bipolar battery of the present disclosure will be described below.

[0046] <First Electrode Active Material Layer and Second Electrode Active Material Layer> In the bipolar battery 1 of the present disclosure, the first electrode active material layer 110 is disposed on the first current collector 11 side, and the second electrode active material layer 120 is disposed on the second current collector 12 side.

[0047] In the present disclosure, one of the first electrode active material layer 110 and the second electrode active material layer 120 may be a negative electrode active material layer, and the other may be a positive electrode active material layer. That is, for example, when the first electrode active material layer is a negative electrode active material layer, the second electrode active material layer may be a positive electrode active material layer, and when the first electrode active material layer is a positive electrode active material layer, the second electrode active material layer may be a negative electrode active material layer.

[0048] For example, when the first electrode active material layer 110 is a negative electrode active material layer and the second electrode active material layer 120 is a positive electrode active material layer, the first electrode active material layer may be formed from a negative electrode mixture containing a negative electrode active material and optionally containing a conductive additive, a binder, etc., and the second electrode active material layer may be formed from a positive electrode mixture containing a positive electrode active material and optionally containing a conductive additive, a binder, etc.

[0049] In the present disclosure, a "composite" refers to a composition that can constitute an electrode active material layer either as is or by further containing other components. Also, in the present disclosure, a "composite slurry" refers to a slurry that contains a "composite" and a dispersion medium and that can be applied and dried to form an electrode active material layer.

[0050] (Negative electrode active material) The negative electrode active material is not particularly limited as long as it has a lower potential than the positive electrode active material. When the bipolar battery of the present disclosure is a lithium ion secondary battery, examples of the negative electrode active material include carbonaceous materials such as graphite, resin carbon, carbon fiber, activated carbon, hard carbon, and soft carbon; metal-based materials mainly composed of tin, tin alloys, silicon, silicon alloys, gallium, gallium alloys, indium, indium alloys, aluminum, and aluminum alloys; conductive polymers such as polyacene, polyacetylene, and polypyrrole; metallic lithium; and Li4Ti5O 12 and lithium alloys such as Li-Si alloys, Li-Sn alloys, Li-Al alloys, Li-Ga alloys, Li-Mg alloys, and Li-In alloys. These negative electrode active materials may be used singly or in combination of two or more.

[0051] The content of the negative electrode active material in the negative electrode mixture is not particularly limited, but may be 50 mass % or more, 70 mass % or more, 90 mass % or more, or 95 mass % or more.

[0052] The negative electrode active material may be in the form of particles, for example.

[0053] (Cathode active material) The positive electrode active material is not particularly limited as long as it has a more noble potential than the negative electrode active material. When the bipolar battery of the present disclosure is a lithium ion secondary battery, the positive electrode active material may be, for example, lithium cobalt oxide (LiCoO), lithium nickel oxide (LiNiO), lithium manganese oxide (LiMnO), solid solution oxide (LiMnO-LiMO (M=Co, Ni, etc.)), lithium nickel manganese oxide (LiNi 1 / 2 Mn 1 / 2 O2), lithium nickel cobalt manganese oxide (LiNi 1 / 3 Mn 1 / 3 Co 1 / 3 Examples of the cathode active materials that can be used include composite oxides such as lithium phosphate oxide (LiFePO4), olivine-type lithium phosphate oxide (LiFePO4), and conductive polymers such as polyaniline and polypyrrole; sulfide-based cathode active materials such as LiS, CuS, Li-Cu-S compounds, TiS2, FeS, MoS2, Li-Mo-S compounds, Li-Ti-S compounds, and Li-VS compounds; and sulfur-based active materials such as sulfur-impregnated acetylene black, sulfur-impregnated porous carbon, and mixed powders of sulfur and carbon. These cathode active materials may be used alone or in combination of two or more.

[0054] The content of the positive electrode active material in the positive electrode mixture is not particularly limited, but may be 50 mass % or more, 70 mass % or more, 90 mass % or more, or 95 mass % or more.

[0055] The positive electrode active material may be in the form of particles, for example.

[0056] (Conductive additive) The conductive additive is not particularly limited, but when the bipolar battery of the present disclosure is a lithium ion secondary battery, examples include graphites such as natural graphite and artificial graphite; carbon blacks such as acetylene black, ketjen black, channel black, furnace black, lamp black, and thermal black; carbon fibers such as carbon nanotubes, conductive fibers such as metal fibers; metal powders such as aluminum powder; conductive whiskers such as zinc oxide whiskers and conductive potassium titanate whiskers; conductive metal oxides such as titanium oxide; organic conductive materials such as phenylene derivatives; etc. These conductive additives may be used alone or in combination of two or more.

[0057] The content of the conductive additive in the negative electrode mixture and the positive electrode mixture is not particularly limited and can be set appropriately depending on the desired conductivity, etc.

[0058] (binder) The binder is not particularly limited, but when the bipolar battery of the present disclosure is a lithium ion secondary battery, examples of the binder include polyvinylidene fluoride (PVdF), polytetrafluoroethylene, polyethylene, polypropylene, aramid resin, polyamide, polyimide, polyamideimide, polyvinyl alcohol, polyacrylonitrile, polyacrylic acid, polymethyl acrylate, polyethyl acrylate, polyhexyl acrylate, polymethacrylic acid, polymethyl methacrylate, polyethyl methacrylate, polyhexyl methacrylate, polyvinyl acetate, polyvinylpyrrolidone, polyether, polyethersulfone, polyhexafluoropropylene, styrene-butadiene rubber, carboxymethyl cellulose, etc. These binders may be used alone or in combination of two or more.

[0059] The content of the conductive additive in the negative electrode mixture and the positive electrode mixture is not particularly limited, and can be set appropriately depending on the desired binding properties, etc.

[0060] In accordance with the present disclosure, bipolar electrodes can be manufactured, for example, by the following method: A solvent is added to and mixed with a first (or second) electrode mixture to prepare a first (or second) electrode mixture slurry, and the slurry is applied to one side of a current collector for a bipolar battery using an applicator or the like, followed by drying to form a first (or second) electrode active material layer; A solvent is added to and mixed with a second (or first) electrode mixture to prepare a second (or first) electrode mixture slurry, and this slurry is applied to the other side of a current collector for a bipolar battery using an applicator or the like and dried to form a second (or first) electrode active material layer, thereby obtaining a laminate; The resulting laminate is pressed by a roll press or the like while applying a predetermined load.

[0061] <Electrolyte layer> The electrolyte layer 130 may be disposed between the first electrode active material layer 110 and the second electrode active material layer 120. The electrolyte layer may be a porous separator impregnated with a nonaqueous electrolyte solution, a solid electrolyte layer containing a solid electrolyte, or a combination thereof.

[0062] The porous separator is not particularly limited as long as it electrically insulates the first electrode active material layer from the second electrode active material layer and, when the bipolar battery of the present disclosure is a lithium-ion secondary battery, allows lithium ions to pass through. For example, a porous membrane can be used as the porous separator. Examples of the porous membrane include microporous polymer films, and examples of the material include polyolefin, polyimide, polyvinylidene fluoride, and polyester.

[0063] A non-aqueous electrolyte is a solution of an electrolyte dissolved in a solvent. Any known lithium salt can be used as the electrolyte, and the electrolyte can be selected depending on the type of active material. For example, LiClO4, LiBF4, LiPF6, LiCF3SO3, LiCF3CO2, LiAsF6, LiSbF6, LiB 10 Cl 10, LiAlCl4, LiCl, LiBr, LiB(C2H5)4, CF3SO3Li, CH3SO3Li, LiCF3SO3, LiC4F9SO3, Li(CF3SO2)2N, lithium carboxylates of lower fatty acids, etc.

[0064] The solvent for dissolving the electrolyte is a liquid that is usually used to dissolve the electrolyte. The solvent is not particularly limited as long as it is, and examples thereof include carbonates such as ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), dimethyl carbonate (DMC), diethyl carbonate (DEC), methyl ethyl carbonate (MEC), and vinylene carbonate (VC); lactones such as γ-butyrolactone and γ-valerolactone; ethers such as trimethoxymethane, 1,2-dimethoxyethane, diethyl ether, 2-ethoxyethane, tetrahydrofuran, and 2-methyltetrahydrofuran; and sulfoxides such as dimethyl sulfoxide. Examples of suitable amines include oxolanes such as 1,3-dioxolane and 4-methyl-1,3-dioxolane; nitrogen-containing compounds such as acetonitrile, nitromethane, formamide, and dimethylformamide; organic acid esters such as methyl formate, methyl acetate, ethyl acetate, butyl acetate, methyl propionate, and ethyl propionate; phosphate triesters and diglymes; triglymes; sulfolanes such as sulfolane and methylsulfolane; oxazolidinones such as 3-methyl-2-oxazolidinone; and sultones such as 1,3-propane sultone, 1,4-butane sultone, and naphthasultone. These may be used alone or in combination of two or more.

[0065] The solid electrolyte constituting the solid electrolyte layer is not particularly limited, and when the bipolar battery of the present disclosure is a lithium ion secondary battery, examples thereof include inorganic solid electrolytes such as sulfide-based solid electrolytes, oxide-based solid electrolytes, and other lithium-based inorganic solid electrolytes; and organic solid electrolytes such as polymer electrolytes.

[0066] Examples of sulfide-based solid electrolytes include, for example, Li2S-P2S5, Li2S-SiS2, Li2S-GeS2, Li2S-Al2S3, Li2S-SiS2-Li3PO4, Li2S-P2S5-GeS2, Li2S-Li2O-P2S5-SiS2, Li2S-GeS2-P2S5-SiS2, Li2S-SnS2-P2S5-SiS2, and the like. These may be used alone or in combination of two or more.

[0067] Examples of oxide-based solid electrolytes include NASICON types such as LiTi2(PO4)3, LiZr2(PO4)3, LiGe2(PO4)3, and perovskite types such as (La 0.5+x Li 0.5-3x )TiO3, and the like.

[0068] Examples of other lithium-based inorganic solid electrolytes include, for example, LiPON, LiNbO3, LiTaO3, Li3PO4, LiPO 4-x N x (where x is 0 < x ≤ 1), LiN, LiI, LISICON, and the like.

[0069] Furthermore, glass ceramics obtained by precipitating crystals of these inorganic solid electrolytes can also be used as solid electrolytes.

[0070] Examples of organic solid electrolytes include, for example, polymer electrolytes such as dry polymer electrolytes and gel electrolytes. As the polymer electrolyte, those generally used in lithium-ion batteries can be used.

[0071] The shape of the solid electrolyte may be, for example, particulate.

[0072] 〈Other Components〉 The first and second electrode active material layers may contain components other than those described above. Examples of such components include dispersants. Examples of dispersants include carboxymethyl cellulose. <00​​The content of other components in the negative electrode mixture or the positive electrode mixture is not particularly limited and can be set appropriately depending on the desired characteristics. [Explanation of symbols]

[0074] 1. Bipolar battery 11, 21 First current collector 11a First through hole 12, 22 Second current collector 12a Second through hole 13, 23 Conductive adhesive layer 14, 24 Outer conductive adhesive layer 100, 200 Bipolar battery current collector 110 First electrode active material layer 120 Second electrode active material layer 130 Electrolyte layer

Claims

1. the first current collector and the second current collector are bonded together via a conductive adhesive layer; the first current collector has a first through hole, and the conductive adhesive layer extends into the first through hole; and / or a second through hole is provided in the second current collector, and the conductive adhesive layer penetrates into the second through hole; Current collector for bipolar batteries.

2. The current collector for a bipolar battery according to claim 1 , wherein the first through-holes and the second through-holes are provided.

3. The current collector for a bipolar battery according to claim 2 , wherein the first through holes and the second through holes are not provided at positions facing each other in the stacking direction.

4. a ratio of a total area of ​​the first through holes to a total area of ​​the first current collector in a planar direction is 10% or more and 50% or less; and / or a ratio of a total area of ​​the second through holes to a total area of ​​the second current collector in a plane direction is 10% or more and 50% or less; The current collector for a bipolar battery according to claim 1 .

5. a first electrode active material layer, the current collector for a bipolar battery according to any one of claims 1 to 4, and a second electrode active material layer, in this order; the first electrode active material layer is adhered to the bipolar battery current collector by the conductive adhesive layer that has penetrated into the first through-holes, and / or the second electrode active material layer is adhered to the bipolar battery current collector by the conductive adhesive layer that has entered the second through-holes. Bipolar battery.

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