JP6676399B2 - Bipolar lithium-ion battery and method of manufacturing bipolar lithium-ion battery - Google Patents

Description

  The present invention relates to a bipolar lithium-ion battery and a method for manufacturing a bipolar lithium-ion battery.

  A bipolar type lithium ion battery is a battery having a structure in which a bipolar electrode layer is provided between a positive electrode layer and a negative electrode layer. The bipolar electrode layer is an electrode in which a positive electrode active material layer is provided on one surface of a current collector and a negative electrode active material layer is provided on the other surface. Bipolar lithium-ion batteries have attracted attention because they are relatively easy to increase the voltage, reduce the number of parts, reduce the electrical resistance between unit cells, and increase the energy density by reducing unnecessary space.

  Patent Literatures 1 and 2 below describe examples of a bipolar lithium ion battery.

  Patent Literature 1 (Japanese Patent Application Laid-Open No. 2014-116156) discloses a unit cell of a lithium battery in which a positive electrode layer is formed on one surface of a solid electrolyte and a negative electrode layer is formed on the other surface, and the unit cell described above. And a plurality of bipolar stacked batteries including alternately stacked internal electrode layers. The plurality of stacked batteries are stacked via a positive electrode current collector foil and a negative electrode current collector foil, and are electrically connected in parallel. Further, there is described an all-solid battery characterized by being sealed with a mold resin.

Patent Document 2 (Japanese Patent Application Laid-Open No. 2008-103285) discloses an all-solid-state battery including a positive electrode, a negative electrode, and a solid electrolyte, in which a positive electrode active material forming the positive electrode and a negative electrode active material forming the negative electrode are collected as one sheet. A bipolar electrode held on both sides of the conductor, wherein the solid electrolyte contains lithium, phosphorus and sulfur, and the solid electrolyte has a solid-state ³¹ P-NMR spectrum of 90.9 ± 0.4 ppm and 86 ppm. There is described an all-solid-state bipolar battery having a peak attributable to crystals at a position of 0.5 ± 0.4 ppm, wherein the proportion of the crystals in the solid electrolyte is 60 to 100 mol%.

JP 2014-116156 A JP 2008-103285 A

In a conventional bipolar lithium-ion battery, first, an intermediate such as a positive electrode layer, a bipolar electrode layer, a solid electrolyte layer, and a negative electrode layer is formed, and then the intermediate is assembled to form a bipolar lithium-ion battery. However, in order to cope with different voltage specifications for each user, a method of manufacturing a bipolar lithium-ion battery by manufacturing a plurality of unit cells and superimposing the obtained unit cells is preferable.
However, according to the study of the present inventors, in the method of stacking unit cells, unit cells are easily shifted when a plurality of unit cells are stacked to produce a bipolar lithium ion battery, and the unit cells are stacked. It has been clarified that, when the displacement occurs, the positive electrode layer, the negative electrode layer, or the electrolyte layer is missing or collapsed, and a short circuit is likely to occur.
Further, according to the study of the present inventors, although the lamination property of the unit cells is improved by laminating the unit cells via the adhesive, the electrical contact between the unit cells deteriorates, It was found that the internal resistance of the bipolar lithium-ion battery increased.

  The present invention has been made in view of the above circumstances, and provides a bipolar lithium-ion battery having excellent lamination properties between unit cells and excellent electrical contact between the unit cells.

  The present inventors have intensively studied to stably provide a bipolar lithium-ion battery having excellent electrical contact between unit cells and suppressing deviation between unit cells. As a result, by stacking the unit cells via the adhesive resin layer having a through hole, the electrical contact between the unit cells is good, and the displacement between the unit cells is suppressed, which is a bipolar lithium ion battery. Was found to be able to be obtained stably, and led to the present invention.

That is, according to the present invention,
A bipolar lithium-ion battery,
A battery element including a positive electrode layer, a negative electrode layer, one or two or more bipolar electrode layers provided between the positive electrode layer and the negative electrode layer, and a plurality of electrolyte layers,
The electrolyte layer is 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 provided on the other surface of the bipolar electrode current collector. And a layer,
The bipolar electrode current collector, a first current collector, an adhesive resin layer having a through hole, and a second current collector are laminated in this order,
The first current collector and the second current collector are adhered to each other via the adhesive resin layer, and the first current collector and the second current collector are formed of the adhesive resin layer. Direct contact in the through hole,
When the thickness of the central portion in the plane direction of the bipolar type lithium ion battery as X _1, and the thickness of the outer peripheral portion in the plane direction of the bipolar type lithium ion battery and X _2, the difference between X ₁ and X ₂ (X _A bipolar lithium-ion battery having _1- X ₂ ) of 3 μm or more is provided.

Furthermore, according to the present invention,
A battery element including a positive electrode layer, a negative electrode layer, one or two or more bipolar electrode layers provided between the positive electrode layer and the negative electrode layer, and a plurality of electrolyte layers,
The electrolyte layer is 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 provided on the other surface of the bipolar electrode current collector. And a layer,
The bipolar electrode current collector, a first current collector, an adhesive resin layer having a through hole, and a second current collector are laminated in this order,
A manufacturing method for manufacturing a bipolar lithium-ion battery in which the first current collector and the second current collector are bonded via the adhesive resin layer ,
A step of preparing a first unit cell in which the positive electrode current collector, the first positive electrode active material layer, the first electrolyte layer, the first negative electrode active material layer, and the first current collector are stacked in this order,
A step of preparing a second unit cell in which a second current collector, a second positive electrode active material layer, a second electrolyte layer, a second negative electrode active material layer, and a negative electrode current collector are stacked in this order When,
On at least one of a surface of the first current collector opposite to the first negative electrode active material layer and a surface of the second current collector opposite to the second positive electrode active material layer. A step of forming an adhesive resin layer having a through hole,
By adhering the first current collector and the second current collector via the adhesive resin layer, a step of obtaining a laminate in which the first unit cell and the second unit cell are laminated ,
By pressing the laminate, the first current collector and the second current collector, by directly contacting in the through-hole of the adhesive resin layer, the first current collector, A step of forming a bipolar electrode layer in which the adhesive resin layer and the second current collector are stacked in this order,
And a method for manufacturing a bipolar lithium-ion battery comprising:

  ADVANTAGE OF THE INVENTION According to this invention, the bipolar type lithium ion battery excellent in the lamination | stacking property of unit cells and the electrical contact between unit cells can be implement | achieved.

FIG. 2 is a cross-sectional view schematically illustrating an example of the structure of the bipolar lithium-ion battery according to the embodiment. It is sectional drawing which showed typically an example of the structure of the bipolar electrode collector of this embodiment. It is the top view which showed typically an example of the structure of the adhesive resin layer which has the through-hole of this embodiment. FIG. 2 is a cross-sectional view schematically illustrating an example of the structure of the bipolar lithium-ion battery according to the embodiment. FIG. 2 is a cross-sectional view schematically illustrating an example of the structure of the bipolar lithium-ion battery according to the embodiment. FIG. 4 is a process cross-sectional view schematically illustrating an example of a manufacturing process of the bipolar lithium-ion battery of the embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, similar components are denoted by common reference numerals, and description thereof will not be repeated. Also, the figure is a schematic view, and does not match the actual dimensional ratio. Unless otherwise specified, “A to B” in the numerical range represents A or more and B or less.

[Bipolar lithium-ion battery]
First, the bipolar lithium-ion battery 100 of the present embodiment will be described.
FIG. 1 is a cross-sectional view schematically showing an example of the structure of a bipolar lithium-ion battery 100 of the present embodiment. FIG. 2 is a cross-sectional view schematically showing an example of the structure of the bipolar electrode current collector 109 of the present embodiment. FIG. 3 is a plan view schematically illustrating an example of the structure of the adhesive resin layer 109b having the through holes 110 according to the present embodiment.
The bipolar lithium ion battery 100 according to the present embodiment includes a positive electrode layer 101, a negative electrode layer 103, one or more bipolar electrode layers 105 provided between the positive electrode layer 101 and the negative electrode layer 103, and a plurality of And a battery element 200 including the electrolyte layer 107 (107a, 107b).
An electrolyte layer 107a is provided between the positive electrode layer 101 and the bipolar electrode layer 105. An electrolyte layer 107b is provided between the bipolar electrode layer 105 and the negative electrode layer 103. The bipolar electrode layer 105 includes a bipolar electrode current collector 109, a positive electrode active material layer 111b provided on one surface of the bipolar electrode current collector 109, and a negative electrode provided on the other surface of the bipolar electrode current collector 109. An active material layer 113a. The bipolar electrode current collector 109 includes a first current collector 109a, an adhesive resin layer 109b having a through hole, and a second current collector 109c laminated in this order. 109a and the second current collector 109c are adhered via the adhesive resin layer 109b.

Here, the first current collector 109a and the second current collector 109c are in electrical contact with each other, for example, by directly contacting in the through hole 110 of the adhesive resin layer 109b.
In addition, from the viewpoint of further improving the stability of electrical contact between the first current collector 109a and the second current collector 109c and more stably obtaining the bipolar lithium-ion battery 100 having good electrical contact, The electrode current collector 109 has a conductive portion in the through-hole 110 of the adhesive resin layer 109b, and the first current collector 109a and the second current collector 109c are electrically contacted via the conductive portion. Is preferred.

According to the study of the present inventors, a bipolar lithium-ion battery in which unit cells are stacked is likely to be easily displaced when a plurality of unit cells are stacked to form a bipolar lithium-ion battery. It was revealed.
Further, according to the study of the present inventors, although the lamination property of the unit cells is improved by laminating the unit cells via the adhesive, the electrical contact between the unit cells deteriorates, It was found that the internal resistance of the bipolar lithium-ion battery increased.
Under the circumstances described above, the present inventors have intensively studied to stably provide a bipolar lithium-ion battery having excellent electrical contact between unit cells and suppressing displacement between unit cells. As a result, by stacking the unit cells via the adhesive resin layer having a through hole, the electrical contact between the unit cells is good, and the displacement between the unit cells is suppressed, which is a bipolar lithium ion battery. Was found to be able to be obtained stably, and led to the present invention.

  In the bipolar lithium-ion battery 100, the positive electrode layer 101, the bipolar electrode layer 105, and the negative electrode layer 103 are laminated in this order via the electrolyte layers 107 (107a, 107b). Further, the positive electrode active material layer 111a and the negative electrode active material layer 113a are stacked so as to face each other with the electrolyte layer 107a interposed therebetween. Further, the positive electrode active material layer 111b and the negative electrode active material layer 113b are stacked so as to face each other with the electrolyte layer 107b interposed therebetween. In this manner, the first power generation element including the positive electrode active material layer 111a, the electrolyte layer 107a, and the negative electrode active material layer 113a, and the first power generation element including the positive electrode active material layer 111b, the electrolyte layer 107b, and the negative electrode active material layer 113b A second power generation element is formed. In the present embodiment, one bipolar electrode layer 105 is stacked between the positive electrode layer 101 and the negative electrode layer 103; however, the present invention is not limited to this, and the design value of the supply voltage of the bipolar lithium-ion battery 100 is If necessary, two or more bipolar electrode layers 105 may be stacked. In that case, the electrolyte layer 107 is also arranged between the bipolar electrode layer 105 and the bipolar electrode layer 105 adjacent thereto. Specifically, in two or more bipolar electrode layers 105, a positive electrode active material layer 111 b of a predetermined bipolar electrode layer 105 and a negative electrode active material layer 113 a of another bipolar electrode layer 105 face each other via an electrolyte layer 107. It is laminated so that it does.

  Hereinafter, each component of the bipolar lithium-ion battery 100 will be specifically described.

(Positive electrode layer)
The positive electrode layer 101 is not particularly limited, and a positive electrode generally used for a lithium ion battery can be used. The positive electrode layer 101 generally includes a positive electrode active material layer 111a and a positive electrode current collector 115.
The positive electrode layer 101 is not particularly limited, but can be manufactured according to a generally known method. For example, it can be obtained by forming a positive electrode active material layer 111a containing a positive electrode active material over the positive electrode current collector 115.
The thickness and density of the positive electrode layer 101 are not particularly limited because they are appropriately determined according to the intended use of the battery and the like, and can be set according to generally known information.
Further, the thickness of the positive electrode layer 101 is set at the center in the plane direction from the viewpoint of more effectively making contact between the first current collector 109a and the second current collector 109c in the through hole 110 of the adhesive resin layer 109b. It is preferable that the thickness near the portion is thicker than the thickness near the outer peripheral portion in the plane direction.

  The positive electrode current collector 115 is not particularly limited, and those generally used for lithium ion batteries can be used. For example, copper foil, copper alloy foil, nickel foil, aluminum foil, aluminum alloy foil, stainless steel Examples include foil and carbon sheet. From the viewpoints of price, availability, electrochemical stability, and the like, the positive electrode current collector 115 is preferably an aluminum foil. Further, the thickness of the positive electrode current collector 115 is not particularly limited, but for example, a thickness in the range of 0.001 to 0.5 mm is preferably used.

The positive electrode active material layer 111a is not particularly limited, but may include, as a component other than the positive electrode active material, for example, one or two or more materials selected from a solid electrolyte material, a binder, a conductive additive, and the like.
The mixing ratio of the various materials in the positive electrode active material layer 111a is not particularly limited because it is appropriately determined according to the intended use of the battery and the like, and can be set according to generally known information.

The positive electrode active material according to this embodiment is not particularly limited, and a generally known positive electrode active material that can be used for a positive electrode of a lithium ion battery can be used. For example, lithium cobalt oxide (LiCoO ₂ ), lithium nickel oxide (LiNiO ₂ ), lithium manganese oxide (LiMn ₂ O ₄ ), solid solution oxide (Li ₂ MnO ₃ -LiMO ₂ (M = Co, Ni, etc.) ), Composite oxides such as lithium-manganese-nickel oxide (LiNi _1/3 Mn _1/3 Co _1/3 O ₂ ), olivine type lithium phosphate (LiFePO ₄ ); and high conductivity such as polyaniline and polypyrrole. _{molecule; Li 2 S, CuS, Li} -CuS _{compounds, TiS 2, FeS, MoS 2} , Li-MoS compounds, Li-TiS compound, sulfide-based positive active such as Li-V-S compound Materials; acetylene black impregnated with sulfur, porous carbon impregnated with sulfur, a material using sulfur as an active material such as a mixed powder of sulfur and carbon; It is possible. One of these positive electrode active materials may be used alone, or two or more thereof may be used in combination.
Among these, from the viewpoint of having a higher discharge capacity density and being more excellent in cycle characteristics, a sulfide-based positive electrode active material is preferable, and a Li-Mo-S compound, a Li _- Ti _- S compound, and a Li _- V _- S One or more selected from compounds is more preferable.

Here, the Li-Mo-S compound contains Li, Mo, and S as constituent elements, and is usually obtained by mixing and pulverizing molybdenum sulfide and lithium sulfide as raw materials by mechanochemical treatment or the like. be able to.
The Li-Ti-S compound contains Li, Ti, and S as constituent elements, and is usually obtained by mixing and pulverizing raw materials of titanium sulfide and lithium sulfide by mechanochemical treatment or the like. Can be.
The Li-VS compound contains Li, V, and S as constituent elements, and can usually be obtained by mixing and pulverizing vanadium sulfide and lithium sulfide, which are raw materials, by mechanochemical treatment or the like. .

Examples of the shape of the positive electrode active material according to the present embodiment include fine particles.
The particulate positive electrode active material according to this embodiment is not particularly limited, but the average particle diameter d ₅₀ in the weight-based particle size distribution measured by a laser diffraction scattering type particle size distribution measurement method is preferably 0.5 μm or more and 20 μm or less, Preferably it is 1 μm or more and 10 μm or less.
The average particle size d ₅₀ of the positive electrode active material to be in the above range, while maintaining good handling properties, can be manufactured more density of the positive electrode.

  The solid electrolyte material is not particularly limited, but those generally used for lithium ion batteries can be used. For example, an inorganic solid electrolyte material such as a sulfide-based solid electrolyte material, an oxide-based solid electrolyte material, and other lithium-based inorganic solid electrolyte materials; and an organic solid electrolyte material such as a polymer electrolyte can be exemplified. Among these, a sulfide-based solid electrolyte material is preferable. Thereby, the interface resistance with the positive electrode active material is further reduced, and a lithium ion battery having excellent output characteristics can be obtained.

Examples of the sulfide-based solid electrolyte material include a Li ₂ S—P ₂ S ₅ material, a Li ₂ S—SiS ₂ material, a Li ₂ S—GeS ₂ material, a Li ₂ S—Al ₂ S ₃ material, and a Li _{2 S-SiS} 2 _-Li 3 PO _{4 material, Li 2 S-P 2 S} 5 -GeS 2 _{material, Li 2 S-Li 2 O} -P 2 S 5 -SiS 2 _{material, Li 2 S-GeS 2 -P} 2 S ₅ -SiS _{2 material, Li 2 S-SnS 2 -P} 2 S 5 -SiS 2 materials, and the like. These may be used alone or in combination of two or more. Among these, a Li ₂ S—P ₂ S ₅ material is preferable because it has excellent lithium ion conductivity and has stability that does not cause decomposition or the like in a wide voltage range. Here, for example, the Li ₂ S—P ₂ S ₅ material means a material obtained by mixing and pulverizing a mixture containing at least Li ₂ S (lithium sulfide) and P ₂ S ₅ by mechanochemical treatment or the like. I do.

Examples of the oxide-based solid electrolyte material, for _{example, LiTi 2 (PO 4) 3} , LiZr 2 (PO 4) 3, LiGe 2 (PO 4) 3 , etc. NASICON _{type, (La} 0.5 _{+ x Li 0.5- 3x} ) Perovskite type such as TiO _{3 and the} like.
Other lithium-based inorganic solid electrolyte material, for _{example, LiPON, LiNbO 3, LiTaO 3} , Li 3 PO 4, LiPO 4-x N x (x is 0 <x ≦ 1), LiN , LiI, LISICON like can be mentioned Can be Further, glass ceramics obtained by depositing these inorganic solid electrolyte crystals can also be used as the solid electrolyte material.

As the organic solid electrolyte material, for example, a polymer electrolyte such as a dry polymer electrolyte and a gel electrolyte can be used.
As the polymer electrolyte, those generally used for lithium ion batteries can be used.

Examples of the shape of the solid electrolyte material include a particle shape. Although the particulate solid electrolyte material is not particularly limited, the average particle diameter d ₅₀ in the weight-based particle size distribution measured by a laser diffraction scattering type particle size distribution measurement method is preferably 1 μm or more and 20 μm or less, more preferably 1 μm or more and 10 μm or less. is there.
The average particle size d ₅₀ of the solid electrolyte material to be in the above range, while maintaining good handling properties, it is possible to further improve the lithium ion conductivity.

The conductive auxiliary agent is not particularly limited as long as it is a normal conductive auxiliary agent usable for lithium ion batteries. Examples thereof include graphites such as natural graphite and artificial graphite; acetylene black, Ketjen black, channel black, and furnace black. , Lamp black, carbon black, such as thermal black; conductive fibers, such as carbon fiber and metal fiber; metal powder, such as aluminum powder; conductive whiskers, such as zinc oxide whisker and conductive potassium titanate whisker; Conductive metal oxides such as titanium; organic conductive materials such as phenylene derivatives; and the like. These conductive assistants may be used alone or in combination of two or more.
Among these, carbon blacks having a small particle size and a low price are preferable.

As the binder, a polymer electrolyte and other binders can be used. Among the polymer electrolytes, a dry polymer electrolyte is preferable. Further, the polymer electrolyte may be used in combination with another binder.
The binder other than the polymer electrolyte is not particularly limited as long as it is a binder generally used in lithium ion batteries. For example, polyvinylidene fluoride (PVdF), polytetrafluoroethylene, polyethylene, polypropylene, aramid resin, polyamide, Polyimide, polyamide imide, polyvinyl alcohol, polyacrylonitrile, polyacrylic acid, polymethyl acrylate, polyethyl acrylate, polyhexyl acrylate, polymethacrylic acid, polymethyl methacrylate, polyethyl methacrylate, polyhexyl methacrylate, poly Examples include vinyl acetate, polyvinyl pyrrolidone, polyether, polyether sulfone, polyhexafluoropropylene, styrene butadiene rubber, carboxymethyl cellulose, and the like. These binders may be used alone or in combination of two or more.

(Method of manufacturing positive electrode layer)
Next, a method for manufacturing the positive electrode layer 101 will be described.
The positive electrode layer 101 is not particularly limited; for example, the positive electrode layer 101 can be manufactured by forming the positive electrode active material layer 111a by attaching the fine particle-shaped positive electrode active material to the positive electrode current collector 115. . For example, it can be manufactured by the following method.

First, a positive electrode active material, and if necessary, a conductive auxiliary agent, a solid electrolyte material, and the like are mixed by a mixer. The mixing ratio of each material is appropriately determined according to the intended use of the battery.
Known mixers such as a ball mill and a planetary mixer can be used, and are not particularly limited. The mixing method is not particularly limited, and the mixing can be performed according to a known method.

Subsequently, the obtained mixture containing the positive electrode active material is attached to the positive electrode current collector 115 so as to have a predetermined thickness, thereby forming the positive electrode active material layer 111a. Thus, the positive electrode layer 101 can be obtained.
Further, a step of removing a positive electrode active material or the like that is not completely adhered on the positive electrode current collector 115 may be further performed. In addition, by pressing the surface on which the positive electrode active material or the like is attached, the adhesion of the positive electrode active material layer 111a is increased, so that desorption of the positive electrode active material or the like is suppressed, May be improved. Alternatively, the thickness and density of the positive electrode active material layer 111a may be adjusted by pressing the surface to which the positive electrode active material and the like are attached. As a pressing method, a generally known method can be used.

  The method for attaching the mixture containing the positive electrode active material to the positive electrode current collector 115 is not particularly limited, but a method for directly supplying the mixture containing the positive electrode active material onto the positive electrode current collector 115 in air or an inert atmosphere. Alternatively, there is a method in which a mixture containing the positive electrode active material is dispersed in a dispersion to form a slurry, and the slurry is supplied to the positive electrode current collector 115. From the viewpoint of controlling the thickness of the positive electrode active material layer 111a to a high degree, a method of directly supplying a mixture containing the positive electrode active material onto the positive electrode current collector 115 in air or an inert atmosphere is preferable.

  As a method of directly supplying the mixture containing the positive electrode active material on the positive electrode current collector 115 in the air or in an inert atmosphere, a method of dropping the mixture containing the positive electrode active material on the positive electrode current collector 115, And a method of spraying the mixture containing the mixture onto the positive electrode current collector 115.

From the viewpoint of controlling the thickness of the positive electrode active material layer 111a to a higher degree, the mixture containing the positive electrode active material is filled in the voids of the porous body, and the mixture filled in the voids of the porous body is sieved on the positive electrode current collector 115. It is preferable to form the positive electrode active material layer 111a on the positive electrode current collector 115 by dropping. Examples of the form of the porous body include one or more selected from woven fabric, nonwoven fabric, mesh cloth, porous membrane, expanded sheet, punched sheet, and the like. Among them, mesh cloth is preferred from the viewpoint of excellent filling properties of the mixture containing the positive electrode active material and excellent performance of sifting the mixture containing the positive electrode active material.
Examples of the material constituting the porous body include nylon, polyester such as polyethylene terephthalate (PET), polyethylene, polypropylene, polytetrafluoroethylene (PTFE), ethylene-tetrafluoroethylene copolymer, polyvinylidene fluoride, and polyvinylidene chloride. , Polyvinyl chloride, polyurethane, vinylon, polybenzimidazole, polyimide, polyphenylene sulphite, polyether ether ketone, cellulose, acrylic resin and other resin materials; natural fibers such as hemp, wood pulp and cotton linter; iron, aluminum and titanium And one or more selected from inorganic materials such as glass, carbon and the like.
Among these, resin materials and natural fibers are preferred from the viewpoint of excellent flexibility, resin materials are more preferred, and nylon is particularly preferred.

  In addition, by supplying a mixture containing more positive electrode active material in the vicinity of the center in the surface direction of the positive electrode current collector 115 than in the vicinity of the outer periphery, the thickness in the vicinity of the center in the surface direction is reduced. A positive electrode layer 101 thicker than the thickness in the vicinity of the portion can be obtained.

(Negative electrode layer)
The negative electrode layer 103 is not particularly limited, and a negative electrode generally used for a lithium ion battery can be used. The negative electrode layer 103 generally includes a negative electrode active material layer 113b and a negative electrode current collector 117.
The negative electrode layer 103 is not particularly limited, but can be manufactured according to a generally known method. For example, it can be obtained by forming the negative electrode active material layer 113b including the negative electrode active material on the negative electrode current collector 117.
The thickness and density of the negative electrode layer 103 are not particularly limited because they are appropriately determined according to the intended use of the battery and the like, and can be set according to generally known information.
Further, the thickness of the negative electrode layer 103 is set at the center in the plane direction from the viewpoint of more effectively making contact between the first current collector 109a and the second current collector 109c in the through hole 110 of the adhesive resin layer 109b. It is preferable that the thickness near the portion is thicker than the thickness near the outer peripheral portion in the plane direction.

  The negative electrode current collector 117 is not particularly limited, and those generally used for lithium ion batteries can be used. For example, copper foil, copper alloy foil, nickel foil, aluminum foil, aluminum alloy foil, stainless steel Examples include foil and carbon sheet. From the viewpoints of price, availability, electrochemical stability, and the like, the negative electrode current collector 117 is preferably a copper foil. The thickness of the negative electrode current collector 117 is not particularly limited, but is preferably, for example, in the range of 0.001 to 0.5 mm.

The negative electrode active material layer 113b is not particularly limited, but may include, as a component other than the negative electrode active material, for example, one or more materials selected from a solid electrolyte material, a binder, a conductive additive, and the like. Specific examples of the solid electrolyte material, the binder, and the conductive additive include the same ones as those described above for the positive electrode active material layer 111a.
The mixing ratio of the various materials in the negative electrode active material layer 113b is not particularly limited because it is appropriately determined according to the intended use of the battery and the like, and can be set according to generally known information.

The negative electrode active material is not particularly limited, and a generally known negative electrode active material that can be used for a negative electrode of a lithium ion battery can be used. For example, carbonaceous materials such as natural graphite, artificial graphite, resin charcoal, carbon fiber, activated carbon, hard carbon, soft carbon; tin, tin alloy, silicon, silicon alloy, gallium, gallium alloy, indium, indium alloy, aluminum, aluminum Metal-based materials mainly composed of alloys and the like; conductive polymers such as polyacene, polyacetylene, and polypyrrole; metallic lithium; lithium-titanium composite oxide (for example, Li ₄ Ti ₅ O ₁₂ ); Li-Si alloy, Li-Sn alloy, and Li Lithium alloys such as -Al alloy, Li-Ga alloy, Li-Mg alloy and Li-In alloy; These negative electrode active materials may be used alone or in combination of two or more.

Examples of the shape of the negative electrode active material include a fine particle shape and a foil shape.
The particulate negative electrode active material according to the present embodiment is not particularly limited, but the average particle diameter d ₅₀ in the weight-based particle size distribution by a laser diffraction / scattering type particle size distribution measurement method is preferably 1 μm or more and 50 μm or less, more preferably 5 μm or more and 30 μm or less.
The average particle size d ₅₀ of the negative electrode active material to be in the above range, while maintaining good handling properties, it can be manufactured more density of the negative electrode.

(Method of manufacturing negative electrode layer)
Next, a method for manufacturing the negative electrode layer 103 will be described.
The negative electrode layer 103 is not particularly limited. For example, the negative electrode layer 103 can be manufactured by forming the negative electrode active material layer 113b by attaching the fine particle-shaped negative electrode active material to the negative electrode current collector 117. . Alternatively, the negative electrode active material layer 113b may be formed by pressing the negative electrode active material in a foil shape over the negative electrode current collector 117.
As a method for producing the negative electrode layer 103 by forming the negative electrode active material layer 113b by attaching the fine particle-shaped negative electrode active material on the negative electrode current collector 117, for example, the above-described method for producing the positive electrode layer 101 A similar method can be used.

(Bipolar electrode layer)
The bipolar electrode layer 105 includes a bipolar electrode current collector 109, a positive electrode active material layer 111b provided on one surface of the bipolar electrode current collector 109, and a negative electrode provided on the other surface of the bipolar electrode current collector 109. An active material layer 113a.
The bipolar electrode current collector 109 includes a first current collector 109a, an adhesive resin layer 109b having a through hole 110, and a second current collector 109c stacked in this order. The body 109a and the second current collector 109c are bonded via the adhesive resin layer 109b.
Here, the first current collector 109a and the second current collector 109c are in direct contact, for example, in the through hole 110 of the adhesive resin layer 109b.
In addition, from the viewpoint of further improving the stability of electrical contact between the first current collector 109a and the second current collector 109c and more stably obtaining the bipolar lithium-ion battery 100 having good electrical contact, The electrode current collector 109 has a conductive portion in the through-hole 110 of the adhesive resin layer 109b, and the first current collector 109a and the second current collector 109c are electrically contacted via the conductive portion. Is preferred.

  As the positive electrode active material layer 111b, a structure similar to that of the positive electrode active material layer 111a can be given. In addition, the negative electrode active material layer 113a can have a structure similar to that of the negative electrode active material layer 113b.

  As the first current collector 109a and the second current collector 109c, a bipolar electrode current collector generally used for a bipolar lithium ion battery can be used. For example, copper foil, copper alloy foil, nickel foil, aluminum foil, aluminum alloy foil, stainless steel foil, carbon sheet, clad material and the like can be mentioned. Examples of the clad material include a laminated material in which a layer mainly containing copper and a layer mainly containing aluminum are joined. The thicknesses of the first current collector 109a and the second current collector 109c are not particularly limited, but, for example, each having a thickness in the range of 0.001 to 0.5 mm is preferably used.

  The adhesive resin layer 109b according to the present embodiment is not particularly limited as long as it has adhesiveness enough to bond the first current collector 109a and the second current collector 109c and has the through-hole 110. For example, a layer composed of an adhesive resin is preferable.

The average thickness of the adhesive resin layer 109b according to the present embodiment is from the viewpoint of more effectively making contact between the first current collector 109a and the second current collector 109c in the through hole 110 of the adhesive resin layer 109b. Therefore, it is preferably 50 μm or less, more preferably 30 μm or less, further preferably 15 μm or less, still more preferably 10 μm or less, still more preferably 8 μm or less, and particularly preferably 5 μm or less.
Further, the average thickness of the adhesive resin layer 109b according to the present embodiment is, from the viewpoint of improving the handleability of the adhesive resin layer 109b and the adhesion between the first current collector 109a and the second current collector 109c. It is preferably at least 0.5 μm, more preferably at least 1 μm, and still more preferably at least 3 μm.

The planar shape (outer shape) of the adhesive resin layer 109b is equivalent to the planar shape of the first current collector 109a and the second current collector 109c.
In the adhesive resin layer 109b, a through hole 110 penetrating the front and back is formed. The planar shape of the through-hole 110 is not particularly limited, but a shape with high symmetry is preferable because a uniform pressure can be applied to the entire surface of the adhesive resin layer 109b. It is preferable that the through-hole 110 is set to a size that allows effective contact between the first current collector 109a and the second current collector 109c.

  In addition, from the viewpoint of improving the adhesiveness between the first current collector 109a and the second current collector 109c, the through hole 110 has a width of 1 mm or more remaining at the end of the adhesive resin layer 109b. It is preferable that the dimensions be as follows.

The adhesive resin layer 109b according to the present embodiment may contain conductive fine particles, but the content of the conductive fine particles is preferably 0.1% when the entire adhesive resin layer 109b is 100% by mass. It is less than 5% by mass, more preferably 0.1% by mass or less, and further preferably 0.05% by mass or less. It is particularly preferable that the adhesive resin layer 109b according to the present embodiment does not contain conductive fine particles.
This makes it possible to obtain even better adhesion while keeping the average thickness of the adhesive resin layer 109b at or below the upper limit.
Here, examples of the conductive fine particles include the same conductive fine particles used for a conductive resin layer described later.

  The adhesive resin contained in the adhesive resin layer 109b according to the present embodiment is not particularly limited as long as it is an adhesive resin, and examples thereof include a (meth) acrylic thermoplastic resin, a silicone resin, a urethane resin, and a polyvinyl ether. , Rubber and the like. Here, in the present embodiment, “(meth) acryl” is used as a generic term for acryl and methacryl.

  In the present embodiment, the (meth) acrylic thermoplastic resin is a thermoplastic resin containing a (meth) acrylic ester unit, for example, a homopolymer of (meth) acrylic ester, two or more ( Copolymers of (meth) acrylic acid esters, (meth) acrylic acid esters, and copolymers thereof with a vinyl monomer having an unsaturated bond copolymerizable therewith, and the like can be given.

  Examples of the (meth) acrylate include methyl (meth) acrylate, ethyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, and tert-butyl (meth) acrylate. Cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, stearyl (meth) acrylate, isobornyl (meth) acrylate, benzyl (meth) acrylate, (meth) benzyl Methoxyethyl acrylate, 2-butoxyethyl (meth) acrylate, 2-phenoxyethyl (meth) acrylate, glycidyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, hexanediol di (meth) acrylate, ethylene Glycol di (meth) acrylate, polyethylene Glycol di (meth) acrylate, propylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol di (meth) acrylate, Pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, urethane acrylate, 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, (meth) ) 2-Hydroxypropyl acrylate, 4-hydroxybutyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 5-hydro (meth) acrylate Cipentyl, 6-hydroxyhexyl (meth) acrylate, 3-hydroxy-3-methylbutyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, pentaerythritol tri (meth) acrylate, 2- [ (Meth) acryloyloxy] ethyl-2-hydroxyethylphthalic acid, 2-[(meth) acryloyloxy] ethyl-2-hydroxypropylphthalic acid and the like.

  Examples of the vinyl monomer having an unsaturated bond copolymerizable with the (meth) acrylic ester include (meth) acrylic acid, maleic anhydride, a maleimide derivative, (meth) acrylonitrile, N-vinylpyrrolidone, and N-vinylpyrrolidone. -Acryloylmorpholine, N-vinylcaprolactone, N-vinylpiperidine, N-vinylformamide, N-vinylacetamide, styrene, indene, α-methylstyrene, p-methylstyrene, p-chlorostyrene, p-chloromethylstyrene, Examples include p-methoxystyrene, p-tert-butoxystyrene, divinylbenzene, butadiene, isoprene, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl caproate, vinyl benzoate, vinyl cinnamate and derivatives thereof. The vinyl monomer having an unsaturated bond copolymerizable with the (meth) acrylate and the (meth) acrylate may be used alone or in combination of two or more.

  The content of the (meth) acrylic acid ester unit contained in the (meth) acrylic thermoplastic resin is such that the whole of the (meth) acrylic thermoplastic resin is 100% by mass from the viewpoint of improving the dispersibility of the conductive fine particles. When performed, it is preferably from 20% by mass to 100% by mass, more preferably from 50% by mass to 100% by mass, and more preferably from 80% by mass to 100% by mass.

  Examples of the silicone resin include polydimethylsiloxane.

  Examples of the polyvinyl ether include polyvinyl methyl ether and polyvinyl ethyl ether.

  Examples of the rubber include natural rubber, isoprene-based rubber, styrene-butadiene-based rubber, and polyisobutylene-based rubber.

  The content of the adhesive resin contained in the adhesive resin layer 109b according to the present embodiment is preferably 80% by mass or more and 100% by mass or less when the entire adhesive resin layer 109b is 100% by mass. Preferably it is 90 mass% or more and 100 mass% or less. When the content of the adhesive resin is within the above range, the balance between the adhesiveness of the adhesive resin layer 109b and the handleability is excellent.

  The adhesive resin layer 109b according to the present embodiment may be, if necessary, a crosslinking agent such as an isocyanate compound, an acid anhydride, an amine compound, an epoxy compound, a metal chelate, an aziridine compound, and a melamine compound; a rosin-based resin, a terpene-based A tackifier resin such as a resin, a petroleum resin, a coumarone-indene resin, a phenolic resin, a xylene resin, and a styrene resin; and a silane coupling agent may be further contained. When the tackifying resin is contained in the tacky resin layer 109b according to the present embodiment, the initial tack and the adhesive force can be easily adjusted.

The adhesive resin layer 109b according to this embodiment is provided on one or both surfaces of the base material and the base material from the viewpoint of further improving the handleability while keeping the average thickness of the adhesive resin layer 109b below the upper limit. The structure provided with the provided adhesive layer is preferable. Thereby, the handleability of the adhesive resin layer 109b is improved, and the productivity of the bipolar lithium-ion battery 100 can be further improved.
The substrate is in the form of a sheet, and examples thereof include a film, a woven fabric, a nonwoven fabric, a mesh cloth, a porous membrane, an expanded sheet, and a punched sheet.

  Examples of the material constituting the base material include polyester such as nylon and polyethylene terephthalate (PET), polyethylene, polypropylene, polytetrafluoroethylene (PTFE), ethylene-tetrafluoroethylene copolymer, polyvinylidene fluoride, and polyvinylidene chloride. And resin materials such as polyvinyl chloride, polyurethane, vinylon, polybenzimidazole, polyimide, polyphenylene sulfite, polyetheretherketone, cellulose, and acrylic resin; and natural fibers such as hemp, wood pulp, and cotton linter.

The method for producing the adhesive resin layer 109b according to the present embodiment is not particularly limited, but for example, it can be produced by the following method.
First, a mixture prepared by mixing an appropriate amount of the adhesive resin, and, if necessary, the crosslinking agent, the tackifier resin, and the silane coupling agent is heated and melted.
After applying the obtained resin composition to one or both surfaces of the substrate, the substrate is cooled to room temperature by cooling or the like to form an adhesive layer on one or both surfaces of the substrate. Thereby, an adhesive resin layer including the base material and the adhesive layers provided on one or both surfaces of the base material can be obtained. The mixing by heating and melting can be carried out usually at a temperature of 100 ° C. to 250 ° C. using a kneader-ruder, an extruder, a mixing mixer, a Banbury mixer and other known kneading apparatuses.
The adhesive resin layer can also be obtained by molding the obtained resin composition into a sheet or film using a known molding method.
Next, by forming a through hole in the obtained adhesive resin layer by punching or the like, the adhesive resin layer 109b having the through hole 110 is obtained.

(Conductive resin layer)
In the current collectors such as the positive electrode current collector 115, the negative electrode current collector 117, the first current collector 109a, and the second current collector 109c according to the embodiment, a conductive material layer is formed on the surface on which the active material layer is formed. Preferably, a resin layer is provided. Thereby, the adhesiveness of each active material layer to each current collector can be increased.
Although the conductive resin layer according to the present embodiment is not particularly limited, for example, a structure including an adhesive resin and conductive fine particles, and a structure in which the conductive fine particles are dispersed in the adhesive resin is preferable.

The thickness of the conductive resin layer according to the present embodiment is appropriately determined in consideration of the average particle size of the conductive fine particles and the properties of the adhesive resin and the like, but is usually 5 μm or more and 60 μm or less, preferably 10 μm or more. It is 40 μm or less.
When the thickness of the conductive resin layer is within the above range, the balance between the adhesiveness between the active material layer and the current collector and the conductivity of the conductive resin layer is excellent.

  The conductive fine particles contained in the conductive resin layer according to the present embodiment are not particularly limited as long as they are conductive fine particles. For example, gold, silver, platinum, zinc, stainless steel, nickel, copper, cobalt, molybdenum , Antimony, iron, chromium and other metal particles; aluminum-magnesium alloy, aluminum-nickel alloy and other alloy particles, tin oxide and indium oxide and other metal oxide particles; nickel and other metal particles such as gold, silver and platinum Particles coated with noble metals; particles obtained by coating non-conductive particles such as glass, ceramic and plastic with noble metals such as gold, silver and platinum; graphites such as natural graphite and artificial graphite, acetylene black, ketjen black, Channel black, furnace black, lamp black, thermal black, and other carbon blacks Bonn particles and the like.

The average particle size d ₅₀ in the weight particle size distribution by a laser diffraction scattering particle size distribution measuring method of the conductive fine particles according to the present embodiment is preferably not 0.5μm or 50μm or less, and more preferably is 5μm or more 30μm or less . The average particle size d ₅₀ to be in the above range, while maintaining good handling properties of the conductive fine particles, it is possible to improve the conductivity of the conductive resin layer.

  The content of the conductive fine particles contained in the conductive resin layer is preferably 0.05% by mass or more and 20% by mass or less, more preferably 0.1% by mass, when the whole of the conductive resin layer is 100% by mass. It is not less than 10% by mass and not more than 10% by mass. When the content of the conductive fine particles is within the above range, the balance between the adhesiveness between the active material layer and the current collector and the conductivity of the conductive resin layer is excellent.

  As the adhesive resin contained in the conductive resin layer according to the present embodiment, the same adhesive resin as that used for the adhesive resin layer 109b described above can be used.

  The content of the (meth) acrylic thermoplastic resin contained in the conductive resin layer according to the present embodiment is preferably 80% by mass or more and 99.95% by mass when the entire conductive resin layer is 100% by mass. Or less, more preferably 90% by mass or more and 99.9% by mass or less. When the content of the (meth) acrylic thermoplastic resin is within the above range, the balance between the adhesion between the active material layer and the current collector and the conductivity of the conductive resin layer is excellent.

(Conductive part)
The conductive portion to be inserted into the through-hole 110 of the adhesive resin layer 109b is not particularly limited as long as it is formed of a material having electron conductivity. For example, the conductive portion is formed of a metal material, a conductive resin material, a carbon material, or the like. Have been.
The metal material is not particularly limited, and a known metal material having electron conductivity can be used. For example, a metal material such as copper, a copper alloy, nickel, aluminum, an aluminum alloy, and stainless steel can be used. As the metal material, a metal foil made of these metals is preferable.
The conductive resin material is not particularly limited, and a known conductive resin material having electron conductivity can be used. For example, a material containing a resin and conductive fine particles, a conductive polymer, and the like can be given. Here, as the conductive fine particles, for example, those similar to the conductive fine particles used in the above-described conductive resin layer can be used. As the resin, for example, a known thermoplastic resin and thermosetting resin can be used. As the conductive polymer, a known conductive polymer can be used.
The carbon material is not particularly limited, and a known carbon material having electron conductivity can be used. For example, graphite, graphene, carbon black, amorphous carbon, carbon fiber and the like can be mentioned.

  The conductive portion only needs to be formed so that the first current collector 109a and the second current collector 109c are in electrical contact with each other, and is formed so as to fill the inside of the through hole 110 of the adhesive resin layer 109b. It may be formed on a part of the through-hole 110 of the adhesive resin layer 109b.

The average thickness of the conductive portion is not particularly limited as long as the first current collector 109a and the second current collector 109c can electrically contact with each other. From the viewpoint of improving the adhesion to the body 109c, preferably 50 μm or less, more preferably 30 μm or less, still more preferably 15 μm or less, even more preferably 10 μm or less, still more preferably 8 μm or less, and particularly preferably 5 μm or less. It is.
Further, the average thickness of the conductive portion is preferably 0.5 μm or more, more preferably 1 μm or more, from the viewpoint of improving the electrical contact between the first current collector 109a and the second current collector 109c. Preferably it is 3 μm or more.

  The shape of the conductive portion is not particularly limited as long as the first current collector 109a and the second current collector 109c can be in electrical contact with each other. For example, the shape is lump, film, sheet, foil, or film. Woven fabric, nonwoven fabric, mesh cloth, porous membrane, expanded sheet, punched sheet and the like.

(Electrolyte layer)
The electrolyte layer 107 is a layer disposed so as to be interposed between the positive electrode active material layer 111a and the negative electrode active material layer 113a and between the positive electrode active material layer 111b and the negative electrode active material layer 113b. Examples of the electrolyte layer 107 include a porous separator in which a non-aqueous electrolyte is impregnated, and a solid electrolyte layer containing a solid electrolyte material.

The porous separator of the present embodiment is not particularly limited as long as it has a function of electrically insulating the positive electrode active material layer and the negative electrode active material layer and transmitting lithium ions, for example, using a porous membrane. Can be.
As the porous film, a microporous polymer film is suitably used, and examples of the material include polyolefin, polyimide, polyvinylidene fluoride, and polyester. Particularly, a porous polyolefin film is preferable, and specific examples include a porous polyethylene film and a porous polypropylene film.

The non-aqueous electrolyte according to the present embodiment is obtained by dissolving an electrolyte in a solvent.
Any known lithium salt can be used as the electrolyte, and may be selected according to the type of active material. For _{example, LiClO 4, LiBF 4, LiPF} 6, LiCF 3 SO 3, LiCF 3 CO 2, LiAsF 6, LiSbF 6, LiB 10 Cl 10, LiAlCl 4, LiCl, LiBr, LiB (C 2 H 5) 4, CF 3 SO ₃ Li, CH ₃ SO ₃ Li, LiCF ₃ SO ₃ , LiC ₄ F ₉ SO ₃ , Li (CF ₃ SO ₂ ) ₂ N, lithium lower fatty acid carboxylate, and the like.

  The solvent for dissolving the electrolyte is not particularly limited as long as it is a liquid usually used for dissolving the electrolyte, and ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), dimethyl carbonate (DMC) , Diethyl carbonate (DEC), methyl ethyl carbonate (MEC), vinylene carbonate (VC), etc .; lactones such as γ-butyrolactone, γ-valerolactone; trimethoxymethane, 1,2-dimethoxyethane, diethyl ether Ethers such as 1,2-ethoxyethane, tetrahydrofuran and 2-methyltetrahydrofuran; sulfoxides such as dimethylsulfoxide; oxolanes such as 1,3-dioxolan and 4-methyl-1,3-dioxolan; acetonito Nitrogen-containing compounds such as ril, nitromethane, formamide and dimethylformamide; organic acid esters such as methyl formate, methyl acetate, ethyl acetate, butyl acetate, methyl propionate and ethyl propionate; phosphoric acid triesters and diglymes; triglymes Sulfolane such as sulfolane and methyl sulfolane; oxazolidinones such as 3-methyl-2-oxazolidinone; sultones such as 1,3-propane sultone, 1,4-butane sultone and naphtha sultone; These may be used alone or in combination of two or more.

  The solid electrolyte layer of the present embodiment is a layer made of a solid electrolyte material. The solid electrolyte layer is not particularly limited, and a solid electrolyte layer generally used for an all solid-state lithium ion battery can be used. The solid electrolyte layer is not particularly limited, but can be produced according to a generally known method.

  The solid electrolyte material constituting the solid electrolyte layer is not particularly limited as long as it has lithium ion conductivity, and includes, for example, the same materials as those described above for the positive electrode active material layer 111a. be able to. Among these, a sulfide-based solid electrolyte material is preferable. Thereby, the interface resistance between the solid electrolyte materials is further reduced, and a lithium ion battery having excellent output characteristics can be obtained.

The content of the solid electrolyte material in the solid electrolyte layer of the present embodiment is not particularly limited as long as a desired insulating property can be obtained. For example, the content is in the range of 10% by volume or more and 100% by volume or less. Especially, it is preferable that it is in the range of 50 volume% or more and 100 volume% or less.
Further, the solid electrolyte layer of the present embodiment may contain a binder. By containing a binder, a flexible solid electrolyte layer can be obtained. Examples of the binder include a fluorine-containing binder such as polytetrafluoroethylene and polyvinylidene fluoride. The thickness of the solid electrolyte layer is, for example, in the range of 0.1 μm or more and 1000 μm or less, and particularly preferably in the range of 0.1 μm or more and 300 μm or less.

  The thickness and density of the solid electrolyte layer are not particularly limited because they are appropriately determined according to the intended use of the battery, and can be set according to generally known information.

  The bipolar lithium-ion battery 100 can be an all-solid-state lithium-ion battery by using the above-described solid electrolyte layer as the electrolyte layer 107. Since the all-solid-state lithium-ion battery does not use a flammable organic solvent in the battery, the safety device can be simplified, and the manufacturing cost, productivity, and safety are excellent.

FIG. 4 is a cross-sectional view schematically illustrating an example of the structure of the bipolar lithium-ion battery 100 of the present embodiment.
In the bipolar lithium-ion battery 100, from the viewpoint of suppressing a short circuit between unit cells, the area of one surface of the adhesive resin layer 109b is at least one of the first current collector 109a and the second current collector 109c. It is preferably larger than the area of one surface of the body, and more preferably larger than the area of one surface of at least one of the first current collector 109a and the second current collector 109c.
When the area of one side of at least one of the first current collector 109a and the second current collector 109c is larger than the area of one side, as shown in FIG. 4, the end of the adhesive resin layer 109b can be bent, Short circuit between the unit cells can be suppressed more effectively. In this case, the adhesive resin layer 109b is preferably insulative.

FIG. 5 is a cross-sectional view schematically illustrating an example of the structure of the bipolar lithium-ion battery 100 of the present embodiment.
It is preferable that the bipolar lithium-ion battery 100 further includes a sealing resin portion 120 for sealing the battery element 200. As the sealing resin portion 120, for example, a configuration in which a through-hole penetrating the front and back surfaces thereof is formed, and a battery element 200 can be accommodated in the through-hole, may be mentioned.
Thus, since the battery element 200 is sealed by the sealing resin portion 120, the bipolar lithium-ion battery 100 can have a stable structure.
Specifically, battery element 200 is accommodated in a through hole formed in the frame. Thus, a structure in which the periphery of the battery element 200 is sealed by the sealing resin portion 20 is realized. With such a structure, a short circuit between unit cells or within a unit cell can be further suppressed.
Further, the battery element 200 is accommodated in the through hole in a state where the battery element 200 is not joined to the inner peripheral wall surface of the through hole. Thereby, at least the battery element 200 is not firmly restrained by the inner peripheral wall surface of the through hole, and can move to some extent freely in the through hole. For this reason, since unnecessary stress can be suppressed from being applied to the battery element 200, the quality of the bipolar lithium-ion battery 100 can be easily stabilized.
That is, the bipolar lithium-ion battery 100 can have a structure that is excellent in productivity and can easily stabilize the quality.

The frame is made of, for example, a thin plate made of an insulating resin. The planar shape (outer shape) of the frame body can be any shape, for example, a rounded rectangular shape or the like.
The frame has a through-hole penetrating the front and back. The planar shape of the through hole is equivalent to the planar shape of the battery element 200. It is preferable that the through-hole is set to a size that accommodates the battery element 200 almost without any gap. The thickness of the frame is equal to the thickness of the battery element 200.

The resin material forming the frame is not particularly limited as long as it is a material that can secure sufficient strength to house and hold the battery element 200 inside the through hole. As an example, the frame can be made of a film such as PET or vinyl chloride.
The through hole of the frame body can be formed by, for example, punching.

In the bipolar type lithium ion battery 100, the thickness of the central portion near the surface direction and _{X 1,} when the thickness of the outer peripheral portion near the surface direction was set to _{X 2,} the difference between _{X 1} and _{X 2 (X} 1 -X ₂ ) Is preferably 3 μm or more, more preferably 5 μm or more, and particularly preferably 10 μm or more. Thereby, the contact between the first current collector 109a and the second current collector 109c in the through hole 110 of the adhesive resin layer 109b can be more effectively performed.
The method for setting the difference (X ₁ −X ₂ ) between X ₁ and X ₂ to be equal to or more than the above lower limit is not particularly limited. For example, in the positive electrode layer 101 or the negative electrode layer 103, the thickness near the center in the surface direction is set to (X ₁ −X ₂ ) can be adjusted to be equal to or more than the lower limit by adjusting the thickness in the direction to be greater than the thickness near the outer peripheral portion.

[Method of Manufacturing Bipolar Lithium-Ion Battery]
Next, a method for manufacturing the bipolar lithium-ion battery 100 of the present embodiment will be described. FIG. 6 is a process cross-sectional view schematically illustrating an example of a manufacturing process of the bipolar lithium-ion battery 100 of the present embodiment.
The method of manufacturing the bipolar lithium-ion battery 100 includes, for example, the following five steps (1), (2), (3A), (4) and (5A), or the following (1), (2), It includes five steps of (3B), (4) and (5B).
(1) The positive electrode current collector 115, the positive electrode active material layer 111a (first positive electrode active material layer), the electrolyte layer 107a (first electrolyte layer), and the negative electrode active material layer 113a (first negative electrode active material layer) Step (2) of forming the first unit cell 100a in which the first current collector 109a is stacked in this order; (2) the second current collector 109c, the positive electrode active material layer 111b (the second positive electrode active material layer), Step (3A) of forming a second unit cell 100b in which the layer 107b (second electrolyte layer), the negative electrode active material layer 113b (second negative electrode active material layer), and the negative electrode current collector 117 are stacked in this order. ) The surface of the first current collector 109a opposite to the negative electrode active material layer 113a (first negative electrode active material layer) side and the positive electrode active material layer 111b (second positive electrode active material layer) side of the second current collector 109c Has a through hole 110 on at least one of the opposite surfaces Step (3B) of Forming the Adhesive Resin Layer 109b The surface of the first current collector 109a opposite to the negative electrode active material layer 113a (first negative electrode active material layer) side and the positive electrode active material of the second current collector 109c An adhesive resin layer 109b having a through-hole 110 and having a conductive portion in the through-hole 110 is provided on at least one of the surfaces opposite to the layer 111b (second positive electrode active material layer) side. Forming Step (4) The first unit cell 100a and the second unit cell 100b are stacked by bonding the first current collector 109a and the second current collector 109c via the adhesive resin layer 109b. Step (5A) of Obtaining Laminate 150 By pressing the laminate 150, the first current collector 109a and the second current collector 109c are brought into direct contact with each other in the through-hole 110 of the adhesive resin layer 109b. And the first current collector 109a Step (5B) of forming a bipolar electrode layer 105 in which the adhesive resin layer 109b and the second current collector 109c are laminated in this order (5B). By electrically contacting the current collector 109c through the conductive portion in the through hole 110 of the adhesive resin layer 109b, the first current collector 109a, the adhesive resin layer 109b, and the second current collector Forming bipolar electrode layer 105 in which electric body 109c is laminated in this order

First, (1) the first unit cell 100a in which the positive electrode current collector 115, the positive electrode active material layer 111a, the electrolyte layer 107a, the negative electrode active material layer 113a, and the first current collector 109a are stacked in this order is Make it.
The first unit cell 100a is manufactured according to a generally known method. For example, a positive electrode layer composed of the positive electrode current collector 115 and the positive electrode active material layer 111a, an electrolyte layer 107a, a negative electrode layer composed of the negative electrode active material layer 113a and the first current collector 109a, in this order. It can be obtained by laminating.

Next, (2) a second unit in which the second current collector 109c, the positive electrode active material layer 111b, the electrolyte layer 107b, the negative electrode active material layer 113b, and the negative electrode current collector 117 are stacked in this order The cell 100b is manufactured.
The second unit cell 100b is manufactured according to a generally known method. For example, a positive electrode layer composed of the second current collector 109c and the positive electrode active material layer 111b, an electrolyte layer 107b, and a negative electrode layer composed of the negative electrode active material layer 113b and the negative electrode current collector 117 are arranged in this order. Can be obtained by laminating them.

Next, (3A) at least one of a surface of the first current collector 109a opposite to the negative electrode active material layer 113a and a surface of the second current collector 109c opposite to the positive electrode active material layer 111b. An adhesive resin layer 109b having a through hole 110 is formed thereon. For example, it penetrates at least one of a surface of the first current collector 109a opposite to the negative electrode active material layer 113a and a surface of the second current collector 109c opposite to the positive electrode active material layer 111b. By sticking the adhesive resin layer having holes, the adhesive resin layer 109b having the through holes 110 can be formed.
Alternatively, (3B) at least one of a surface of the first current collector 109a opposite to the negative electrode active material layer 113a and a surface of the second current collector 109c opposite to the positive electrode active material layer 111b. An adhesive resin layer 109b having a through hole 110 and having a conductive portion in the through hole 110 can be formed thereon. For example, on at least one of a surface of the first current collector 109a opposite to the negative electrode active material layer 113a and a surface of the second current collector 109c opposite to the positive electrode active material layer 111b, By bonding an adhesive resin layer having a through hole and having a conductive portion in the through hole, forming an adhesive resin layer 109b having a through hole 110 and having a conductive portion in the through hole 110 can do.

  Next, (4) the first current collector 109a and the second current collector 109c are bonded to each other via the adhesive resin layer 109b, so that the first unit cell 100a and the second unit cell 100b are stacked. Obtain body 150.

Next, (5A) the first current collector 109a and the second current collector 109c are brought into direct contact with each other in the through-hole 110 of the adhesive resin layer 109b by pressing the stacked body 150, whereby The bipolar electrode layer 105 in which the current collector 109a, the adhesive resin layer 109b, and the second current collector 109c are stacked in this order is formed, and the bipolar lithium-ion battery 100 is obtained.
Alternatively, by pressing the (5B) laminate 150, the first current collector 109a and the second current collector 109c are electrically connected to each other via the conductive portion in the through hole 110 of the adhesive resin layer 109b. By contact, the bipolar electrode layer 105 in which the first current collector 109a, the adhesive resin layer 109b, and the second current collector 109c are laminated in this order is formed, and the bipolar lithium-ion battery 100 is obtained. You can also.
By pressing the stacked body 150, the first current collector 109a and the second current collector 109c adhere to each other through the adhesive resin layer 109b, and further come into direct contact with each other in the through hole 110 of the adhesive resin layer 109b. Alternatively, a bipolar electrode current collector 109 is formed by making electrical contact through the conductive portion. By doing so, the first unit cell 100a and the second unit cell 100b are electrically connected.
Further, by pressing the laminate 150, the bipolar lithium-ion battery 100 having a certain strength due to the anchor effect between the layers is obtained.
The pressure for pressing the laminate 150 is, for example, 40 MPa or more and 500 MPa or less.
The method for pressing the laminate 150 is not particularly limited, and for example, a flat plate press, a roll press, or the like can be used.

Further, the laminate 150 may be heated while being pressed as necessary. When heating and pressing are performed, fusion and bonding of the solid electrolyte materials occur, and the strength of the obtained solid electrolyte layer is further increased. As a result, the lack of the solid electrolyte material and the crack on the surface of the solid electrolyte layer can be further suppressed.
The temperature at which the stacked body 150 is heated is, for example, 150 ° C. or more and 500 ° C. or less.

The method for manufacturing the bipolar lithium-ion battery 100 according to the present embodiment uses simple equipment and is excellent in productivity. In addition, since the first current collector 109a and the second current collector 109c are in close contact with each other via the adhesive resin layer 109b, the unit cells are unlikely to be misaligned. Furthermore, since the first current collector 109a and the second current collector 109c are in direct contact with each other or electrically in contact with each other via the conductive portion, the electric resistance between the unit cells can be reduced.
Therefore, the bipolar lithium-ion battery 100 with good yield and excellent electrical contact can be obtained. That is, according to the method for manufacturing the bipolar lithium-ion battery 100 of the present embodiment, the productivity of the bipolar lithium-ion battery 100 can be improved.

Although the embodiments of the present invention have been described above, these are merely examples of the present invention, and various configurations other than the above can be adopted.
It should be noted that the present invention is not limited to the above-described embodiment, but includes modifications and improvements as long as the object of the present invention can be achieved.

  Hereinafter, the present invention will be described with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

[1] Measuring method First, measuring methods in the following examples and comparative examples will be described.

(1) Particle Size Distribution The particle size distribution of the materials used in the examples and comparative examples was measured by a laser diffraction method using a laser diffraction / scattering type particle size distribution analyzer (manufactured by Malvern, Mastersizer 3000). From the measurement results, the particle size (d ₅₀ , average particle size) at the time of 50% accumulation in the weight-based cumulative distribution was determined for each material.

(2) Measurement of AC Impedance The bipolar lithium ion batteries obtained in Examples and Comparative Examples were measured for 25% by using an AC impedance measuring device (SP-300 manufactured by Bio-Logic) while reaching the discharge cutoff voltage. At a temperature of ° C., a 1 kHz impedance (Ω) was measured.

(3) Evaluation of Laminability In each of Examples and Comparative Examples, 10 bipolar lithium-ion batteries were produced by changing the conditions of vacuum lamination using an aluminum laminate film, and the lamination properties were evaluated according to the following criteria.
：: No bipolar lithium ion battery in which a displacement occurred between the first unit cell and the second unit cell. ×: Bipolar lithium in which a displacement occurred between the first unit cell and the second unit cell. There was one or more ion batteries. Note that a shift between the first unit cell and the second unit cell was visually observed, and a case where there was a clear shift was defined as "shift".

(4) Evaluation of Short-Circuit Prevention Property In Examples and Comparative Examples, the initial spontaneous potential when there were no short-circuits was manufactured by changing the conditions of vacuum lamination with an aluminum laminate film to 100 bipolar lithium-ion batteries. The number of batteries that obtained 2 V or more was evaluated in percentage.

(5) Productivity Evaluation In Examples and Comparative Examples, the productivity of the bipolar lithium-ion battery was evaluated based on the number of bipolar lithium-ion batteries manufactured in one hour.

[2] Materials Next, materials used in the following Examples and Comparative Examples will be described.

(1) Production of positive electrode active material (Li ₁₄ MoS ₉ compound) MoS ₂ (manufactured by Wako Pure Chemical Industries, Ltd., 745 mg, 4.7 mmol, average particle size: 10 μm) was placed in an Al ₂ O ₃ pot under an argon atmosphere. And Li ₂ S (manufactured by Sigma-Aldrich Japan, 1497 mg, 32.5 mmol, average particle size: 5 μm) were weighed and added, and a ZrO ₂ ball was further put therein, and the Al ₂ O ₃ pot was sealed.
Next, the Al ₂ O ₃ pot was placed on a ball mill turntable and treated at 120 rpm for 4 days to obtain a mixture.

The resulting Li-Mo-S compound was pulverized by a mortar and classified by a sieve having a mesh opening 43 .mu.m, the average particle size _{d 50} was obtained Li-Mo-S compounds of the 2 [mu] m.
The molar ratio of the Li content to the Mo content (Li / Mo) was 14, and the molar ratio of the S content to the Mo content (S / Mo) was 9.

(2) a sulfide-based solid electrolyte material _{(Li 11 P 3 S 12)} Li 11 P 3 S 12 is produced sulfide-based solid electrolyte material was prepared by the following procedure.
As raw materials, Li ₂ S (manufactured by Sigma-Aldrich Japan, purity 99.9%) and P ₂ S ₅ (reagent manufactured by Kanto Chemical) were used. Li ₃ N was produced by the following procedure.
First, in a glove box in a nitrogen atmosphere, a large number of holes having a diameter of 1 mm or less were formed in a Li foil (Honjo Metal Co., Ltd., purity 99.8%, thickness 0.5 mm) using a stainless steel sword mountain. The Li foil started to change to black-purple from the portion of the hole, and all of the Li foil changed to black-purple Li ₃ N when left at room temperature for 24 hours. Li ₃ N was pulverized in an agate mortar, sieved with a stainless steel sieve, and a powder having a particle size of 75 μm or less was recovered and used as a raw material for an inorganic solid electrolyte material.
Subsequently, each raw material was precisely weighed in an argon glove box such that Li ₂ S: P ₂ S ₅ : Li ₃ N = 67.5: 22.5: 10.0 (mol%), and these powders were weighed. Mix in agate mortar for 20 minutes. Next, 2 g of the mixed powder was weighed, and mixed and pulverized together with 500 g of a zirconia ball having a diameter of 10 mm in a planetary ball mill (P-7, manufactured by Fritsch) at 100 rpm for 1 hour. Next, the mixture was pulverized at 400 rpm for 15 hours to obtain a sulfide-based solid electrolyte material having a Li ₁₁ P ₃ S ₁₂ composition.

<Example 1>
Conductive copper foil conductive tape (Teraoka Seisakusho 8313 0.03, external dimensions: 25.0 mm x 25.0 mm, thickness: 30 µm, electrolytic copper foil: 0.009 mm, conductive acrylic adhesive layer: 0.021 mm Graphite (manufactured by Nippon Graphite Industry Co., Ltd., CGC-20, 8 mg) adhered to the surface of the pressure-sensitive adhesive layer), a negative electrode active material layer (indium foil, manufactured by Nilaco, 23.0 mm × 23.0 mm, average thickness: 20 μm), Solid electrolyte layer (Li ₁₁ P ₃ S ₁₂ , average thickness: 60 μm), positive electrode active material layer (Li ₁₄ MoS ₉ : Ketjen black (KB): Li ₁₁ P ₃ S ₁₂ = 1: 0.5: 1. 2 (mass ratio), average thickness: 30 μm), conductive copper foil conductive tape (8313 0.03, manufactured by Teraoka Seisakusho, external dimensions: 25.0 mm × 25.0 mm, thickness: 30 μm, electrolytic copper foil: 0. 009mm, conductive acrylic -Based pressure-sensitive adhesive layer: 0.021 mm, copper powder (325 mesh, 30 mg, manufactured by Kojundo Chemical Laboratory Co., Ltd.) was laminated on the pressure-sensitive adhesive layer surface in this order. Next, the obtained laminate was pressed at 80 MPa to produce a first unit cell. Here, a second unit cell having the same configuration as the first unit cell was manufactured in the same manner as in the manufacture of the first unit cell.
Next, an adhesive resin layer having a circular through-hole having a diameter of 15 mm in the center (Nitto Denko Corporation, ultra-thin double-sided tape No. 5600, layer constitution: acrylic adhesive layer / PET film base material / acrylic adhesive) The obtained first unit cell and the second unit cell are laminated via the agent layer, total thickness: 5 μm, outer dimensions: 25.0 mm × 25.0 mm) to produce a laminate, and the resulting laminate Was pressurized at 80 MPa. Next, the obtained laminate was vacuum-laminated with an aluminum laminate film to obtain a bipolar lithium-ion battery. AC impedance measurement, lamination property evaluation, short-circuit prevention property evaluation, and productivity evaluation were performed on the bipolar lithium-ion battery. Table 1 shows the obtained results.

<Examples 2 and 3>
Bipolar lithium ion batteries were produced in the same manner as in Example 1 except that the external dimensions of the adhesive resin layer having a circular through hole having a diameter of 15 mm formed in the center were changed to the dimensions shown in Table 1. The same evaluation as in Example 1 was performed. In Example 2, the end of the adhesive resin layer was bent as shown in FIG. Table 1 shows the obtained results.

<Examples 4 to 7>
The external dimensions of the adhesive resin layer having a circular through-hole having a diameter of 15 mm in the center were changed to the dimensions shown in Table 1, and the sealing resin part 120 (a resin frame formed of a PET film) as shown in FIG. The bipolar lithium ion batteries were produced in the same manner as in Example 1 except that (1) was provided, and the same evaluation as in Example 1 was performed. In Examples 4 and 6, the end of the adhesive resin layer was bent as shown in FIG. Table 1 shows the obtained results.

<Example 8>
As a pressure-sensitive adhesive resin layer having a circular through-hole having a diameter of 15 mm in the center, a transparent pressure-sensitive adhesive sheet made by Nitto Denko Corporation (CS9621T, an acrylic pressure-sensitive adhesive layer only, no substrate, thickness: 25 μm, outer dimensions: 25. A bipolar type lithium-ion battery was produced in the same manner as in Example 1 except that 0 mm × 25.0 mm) was used, and the same evaluation as in Example 1 was performed. Table 1 shows the obtained results.

<Example 9>
Nitto Denko Corporation's baseless double-sided adhesive tape (GA5903, acrylic base layer only, no base, thickness: 30 μm, external dimensions) : 25.0 mm x 25.0 mm), and a bipolar lithium-ion battery was produced in the same manner as in Example 1 and evaluated in the same manner as in Example 1. Table 1 shows the obtained results.

<Comparative Example 1>
A bipolar lithium-ion battery was produced in the same manner as in Example 1 except that the adhesive resin layer was not provided between the first unit cell and the second unit cell, and the same evaluation as in Example 1 was performed. Table 1 shows the obtained results.

<Comparative Example 2>
Instead of the adhesive resin layer having a circular through hole having a diameter of 15 mm in the center, an adhesive resin layer having no through hole formed therein (Nitto Denko Corporation, ultra-thin double-sided tape No. 5600, layer configuration: Bipolar lithium-ion battery in the same manner as in Example 1 except that an acrylic pressure-sensitive adhesive layer / PET film substrate / acrylic pressure-sensitive adhesive layer, total thickness: 5 μm, external dimensions: 25.0 mm × 25.0 mm) were used. Was prepared, and the same evaluation as in Example 1 was performed. Table 1 shows the obtained results.

<Comparative Example 3>
Instead of an adhesive resin layer having a circular through-hole having a diameter of 15 mm at the center, a conductive resin layer having no through-hole (7741 manufactured by Teraoka Seisakusho, total thickness: 50 μm, layer configuration: conductive) (Acrylic pressure-sensitive adhesive layer / conductive nonwoven fabric / conductive acrylic pressure-sensitive adhesive layer, external dimensions: 25.0 mm × 25.0 mm) except that a bipolar lithium-ion battery was produced in the same manner as in Example 1. The same evaluation as in Example 1 was performed. Table 1 shows the obtained results.

From Table 1, it is found that the bipolar lithium-ion battery of the example using the adhesive resin layer having the through-hole formed therein did not include the adhesive resin layer between the first unit cell and the second unit cell. It was found that the unit cells were superior in lamination property as compared with the bipolar type lithium ion battery.
Furthermore, the bipolar lithium-ion battery of the example using the adhesive resin layer having a through-hole was compared with the bipolar lithium-ion batteries of Comparative Examples 2 and 3 using a resin layer having no through-hole at all. The 1 kHz impedance was low and the internal resistance was low. That is, it was found that the bipolar lithium ion batteries of the examples had excellent electrical contact between the unit cells.
From the above, it was confirmed that according to the present embodiment, a bipolar lithium-ion battery having excellent lamination properties of the unit cells and electrical contact between the unit cells can be realized.

<Example 10>
A bipolar lithium-ion battery was obtained in the same manner as in Example 4, except that a copper foil (diameter: 10 mm, thickness: 10 μm) was inserted as a conductive portion into the through-hole of the adhesive resin layer. 60 bipolar lithium-ion batteries were produced, and the charge / discharge curves were measured. Next, the ratio of normal batteries having no irregular voltage fluctuation in the charge / discharge curve was determined. Table 2 shows the obtained results. For comparison, 60 bipolar lithium-ion batteries were also prepared for the battery of Example 4, and the percentage of normal batteries having no irregular voltage fluctuation in the charge / discharge curve was determined.

<Example 11>
Except that the conductive part to be inserted into the through-hole of the adhesive resin layer was changed to copper foil (diameter: 14 mm, thickness: 10 μm), 60 bipolar lithium-ion batteries were produced in the same manner as in Example 10, and the same evaluation was performed. Was. Table 2 shows the obtained results.

<Example 12>
Except that the conductive part to be inserted into the through-hole of the adhesive resin layer was changed to copper foil (diameter 10 mm, thickness 2 μm), 60 bipolar lithium-ion batteries were produced in the same manner as in Example 10, and the same evaluation was performed. Was. Table 2 shows the obtained results.

<Example 13>
Except that the conductive part to be inserted into the through-hole of the adhesive resin layer was changed to stainless steel foil (diameter 10 mm, thickness 8 μm), 60 bipolar lithium-ion batteries were produced in the same manner as in Example 10, and the same evaluation was performed. Was. Table 2 shows the obtained results.

<Example 14>
Except that the conductive part to be inserted into the through hole of the adhesive resin layer was changed to aluminum foil (diameter 14 mm, thickness 20 μm), 60 bipolar lithium ion batteries were produced in the same manner as in Example 10, and the same evaluation was performed. Was. Table 2 shows the obtained results.

From Table 2, it can be seen that Examples 10 to 14 in which the conductive portion was inserted inside the through-hole had irregular voltage fluctuations in the charge / discharge curves as compared with Example 4 in which the conductive portion was not inserted inside the through-hole. It was found that the ratio of non-normal batteries was large and that the electrical contact between the unit cells was more excellent .
Hereinafter, examples of the reference embodiment will be additionally described.
1.
A bipolar lithium-ion battery,
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,
The electrolyte layer is 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 provided on the other surface of the bipolar electrode current collector. And a layer,
The bipolar electrode current collector, a first current collector, an adhesive resin layer having a through hole, and a second current collector are stacked in this order,
A bipolar lithium ion battery in which the first current collector and the second current collector are bonded via the adhesive resin layer.
2.
1. In the bipolar lithium ion battery according to the,
A bipolar lithium ion battery in which the first current collector and the second current collector are in direct contact with each other in the through hole of the adhesive resin layer.
3.
2. In the bipolar lithium ion battery according to the,
When the center portion thickness of the vicinity of the plane direction of the bipolar type lithium ion battery and X _1, the thickness of the outer peripheral portion near the surface direction of the bipolar type lithium ion battery was X _2, the difference between X ₁ and X ₂ A bipolar lithium ion battery in which (X ₁ -X ₂ ) is 3 μm or more.
4.
1. In the bipolar lithium ion battery according to the,
The bipolar electrode current collector further has a conductive portion in the through hole of the adhesive resin layer.
A bipolar lithium ion battery in which the first current collector and the second current collector are in electrical contact with each other via the conductive portion.
5.
4. In the bipolar lithium ion battery according to the,
A bipolar lithium-ion battery in which the conductive portion includes at least one layer selected from a metal material, a conductive resin material, and a carbon material.
6.
1. To 5. In the bipolar lithium-ion battery according to any one,
A bipolar lithium-ion battery in which the area of one surface of the adhesive resin layer is equal to or greater than the area of one surface of at least one of the first current collector and the second current collector.
7.
1. To 6. In the bipolar lithium-ion battery according to any one,
A bipolar lithium ion battery wherein the average thickness of the adhesive resin layer is 50 μm or less.
8.
1. To 7. In the bipolar lithium-ion battery according to any one,
A bipolar lithium ion battery in which the content of the conductive fine particles is 0.5% by mass or less when the entirety of the adhesive resin layer is 100% by mass.
9.
1. To 8. In the bipolar lithium-ion battery according to any one,
A bipolar lithium-ion battery in which the adhesive resin layer includes a base material and an adhesive layer provided on one or both surfaces of the base material.
10.
1. To 9. In the bipolar lithium-ion battery according to any one,
Further comprising a sealing resin portion for sealing the battery element,
A bipolar lithium ion battery in which the sealing resin portion is a resin frame having a through-hole penetrating the front and back thereof, and the battery element being housed in the through-hole.
11.
1. To 10. In the bipolar lithium-ion battery according to any one,
A bipolar lithium ion battery in which the electrolyte layer is a solid electrolyte layer made of a solid electrolyte material.
12.
1. To 11. In the bipolar lithium-ion battery according to any one,
A bipolar lithium-ion battery that is an all-solid-state lithium-ion battery.
13.
1. A manufacturing method for manufacturing a bipolar lithium-ion battery according to the above,
A step of preparing a first unit cell in which the positive electrode current collector, the first positive electrode active material layer, the first electrolyte layer, the first negative electrode active material layer, and the first current collector are stacked in this order,
A step of preparing a second unit cell in which a second current collector, a second positive electrode active material layer, a second electrolyte layer, a second negative electrode active material layer, and a negative electrode current collector are stacked in this order When,
On at least one of a surface of the first current collector opposite to the first negative electrode active material layer side and a surface of the second current collector opposite to the second positive electrode active material layer side A step of forming an adhesive resin layer having a through hole,
Bonding the first current collector and the second current collector through the adhesive resin layer to obtain a stacked body in which the first unit cell and the second unit cell are stacked; ,
By pressing the laminate, the first current collector and the second current collector, by directly contacting in the through-hole of the adhesive resin layer, the first current collector, A step of forming a bipolar electrode layer in which the adhesive resin layer and the second current collector are stacked in this order;
A method for manufacturing a bipolar lithium-ion battery comprising:
14．
1. A manufacturing method for manufacturing a bipolar lithium-ion battery according to the above,
A step of preparing a first unit cell in which the positive electrode current collector, the first positive electrode active material layer, the first electrolyte layer, the first negative electrode active material layer, and the first current collector are stacked in this order,
A step of preparing a second unit cell in which a second current collector, a second positive electrode active material layer, a second electrolyte layer, a second negative electrode active material layer, and a negative electrode current collector are stacked in this order When,
On at least one of a surface of the first current collector opposite to the first negative electrode active material layer side and a surface of the second current collector opposite to the second positive electrode active material layer side A step of forming an adhesive resin layer having a through hole, and having a conductive portion in the through hole,
Bonding the first current collector and the second current collector through the adhesive resin layer to obtain a stacked body in which the first unit cell and the second unit cell are stacked; ,
By pressing the laminate, by electrically contacting the first current collector and the second current collector via the conductive portion in the through hole of the adhesive resin layer, A step of forming a bipolar electrode layer in which the first current collector, the adhesive resin layer, and the second current collector are stacked in this order;
A method for manufacturing a bipolar lithium-ion battery comprising:

100 Bipolar lithium ion battery 100a First unit cell 100b Second unit cell 101 Positive electrode layer 103 Negative electrode layer 105 Bipolar electrode layer 107 Electrolyte layer 107a Electrolyte layer 107b Electrolyte layer 109 Bipolar electrode current collector 109a First current collector 109b Adhesion Resin layer 109c Second current collector 110 Through hole 111a Positive electrode active material layer 111b Positive electrode active material layer 113a Negative electrode active material layer 113b Negative electrode active material layer 115 Positive electrode collector 117 Negative current collector 120 Sealing resin part 150 Stack 200 Battery element

Claims (9)

A bipolar lithium-ion battery,
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,
The electrolyte layer is 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 provided on the other surface of the bipolar electrode current collector. And a layer,
The bipolar electrode current collector, a first current collector, an adhesive resin layer having a through hole, and a second current collector are stacked in this order,
The first current collector and the second current collector are bonded via the adhesive resin layer ,
The first current collector and the second current collector are in direct contact in the through-hole of the adhesive resin layer,
When the thickness of the central portion and X ₁ in the plane direction of the bipolar type lithium ion battery, the thickness of the outer peripheral portion in the surface direction of the bipolar type lithium ion battery was X _2, the difference between X ₁ and X ₂ (X _1- X ₂ ) is 3 µm or more . The bipolar lithium-ion battery according to claim 1 ,
A bipolar lithium-ion battery in which the area of one surface of the adhesive resin layer is equal to or greater than the area of one surface of at least one of the first current collector and the second current collector. The bipolar lithium-ion battery according to claim 1 or 2 ,
A bipolar lithium ion battery wherein the average thickness of the adhesive resin layer is 50 μm or less. The bipolar lithium-ion battery according to any one of claims 1 to 3 ,
A bipolar lithium ion battery in which the content of the conductive fine particles is 0.5% by mass or less when the entirety of the adhesive resin layer is 100% by mass. The bipolar lithium-ion battery according to any one of claims 1 to 4 ,
A bipolar lithium-ion battery in which the adhesive resin layer includes a base material and an adhesive layer provided on one or both surfaces of the base material. The bipolar lithium-ion battery according to any one of claims 1 to 5 ,
Further comprising a sealing resin portion for sealing the battery element,
A bipolar lithium ion battery in which the sealing resin portion is a resin frame having a through-hole penetrating the front and back thereof, and the battery element being housed in the through-hole. The bipolar lithium-ion battery according to any one of claims 1 to 6 ,
A bipolar lithium ion battery in which the electrolyte layer is a solid electrolyte layer made of a solid electrolyte material. The bipolar lithium-ion battery according to any one of claims 1 to 7 ,
A bipolar lithium-ion battery that is an all-solid-state lithium-ion battery. 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,
The electrolyte layer is 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 provided on the other surface of the bipolar electrode current collector. And a layer,
The bipolar electrode current collector, a first current collector, an adhesive resin layer having a through hole, and a second current collector are stacked in this order,
A manufacturing method for manufacturing a bipolar lithium-ion battery in which the first current collector and the second current collector are bonded via the adhesive resin layer ,
A step of preparing a first unit cell in which the positive electrode current collector, the first positive electrode active material layer, the first electrolyte layer, the first negative electrode active material layer, and the first current collector are stacked in this order,
A step of preparing a second unit cell in which a second current collector, a second positive electrode active material layer, a second electrolyte layer, a second negative electrode active material layer, and a negative electrode current collector are stacked in this order When,
On at least one of a surface of the first current collector opposite to the first negative electrode active material layer side and a surface of the second current collector opposite to the second positive electrode active material layer side A step of forming an adhesive resin layer having a through hole,
Bonding the first current collector and the second current collector through the adhesive resin layer to obtain a stacked body in which the first unit cell and the second unit cell are stacked; ,
By pressing the laminate, the first current collector and the second current collector, by directly contacting in the through-hole of the adhesive resin layer, the first current collector, A step of forming a bipolar electrode layer in which the adhesive resin layer and the second current collector are stacked in this order;
A method for manufacturing a bipolar lithium-ion battery comprising:

Images