阅读说明：本技术 固体电池 (Solid-state battery ) 是由 谷内拓哉 大田正弘 于 2018-12-07 设计创作，主要内容包括：一种固体电池,其反复层叠有多个固体电池单体,所述固体电池单体包括正极层、负极层、固体电解质层、及夹持它们的一对集电体层,并且,前述集电体层的一面与前述正极层或前述负极层相接,前述集电体层的另一面与相邻的前述固体电池单体的前述集电体层相接,前述集电体层的另一面的摩擦系数大于前述集电体层的一面的摩擦系数。由此,能够提供一种在层叠时不会产生偏移和旋转的固体电池。(A solid-state battery comprising a plurality of solid-state battery cells stacked in layers, wherein each of the solid-state battery cells comprises a positive electrode layer, a negative electrode layer, a solid electrolyte layer, and a pair of current collector layers sandwiching the positive electrode layer, wherein one surface of each of the current collector layers is in contact with the positive electrode layer or the negative electrode layer, wherein the other surface of each of the current collector layers is in contact with the current collector layer of the adjacent solid-state battery cell, and wherein the friction coefficient of the other surface of each of the current collector layers is larger than the friction coefficient of the one surface of each of the current collector layers. This makes it possible to provide a solid-state battery that does not cause misalignment and rotation during stacking.)

1. A solid-state battery comprising a plurality of solid-state battery cells stacked repeatedly, each of the solid-state battery cells comprising a positive electrode layer, a negative electrode layer, a solid electrolyte layer, and a pair of current collector layers sandwiching the positive electrode layer, the negative electrode layer, the solid electrolyte layer, and the pair of current collector layers,

one surface of the current collector layer is in contact with the positive electrode layer or the negative electrode layer,

the other surface of the current collector layer is in contact with the current collector layer of the adjacent solid battery cell,

the friction coefficient of the other surface of the current collector layer is larger than the friction coefficient of the one surface of the current collector layer.

2. The solid-state battery according to claim 1, wherein the surface roughness of the other surface of the current collector layer is larger than the surface roughness of the one surface of the current collector layer.

3. The solid-state battery according to claim 1, wherein the current collector layer comprises a metal foil disposed on the one surface side and a conductive layer disposed on the other surface side.

4. The solid-state battery according to claim 3, wherein the aforementioned conductive layer is a carbon coating layer.

5. The solid-state battery according to claim 1, wherein the current collector layer comprises a metal foil disposed on the one surface side and an adhesive layer having adhesiveness disposed on the other surface side.

Technical Field

The present invention relates to a solid-state battery.

Background

In recent years, the demand for high-capacity, high-output batteries has rapidly increased due to the widespread use of various sizes of electrical and electronic equipment such as automobiles, personal computers, mobile phones, and the like. Among various batteries, there is a high demand for batteries having high energy density and output, and development of batteries having higher performance is desired. Among them, the solid-state battery is attracting attention because it is superior in that its electrolyte is not flammable and thus has high safety and has high energy density.

[ Prior Art document ]

(patent document)

Patent document 1: japanese patent laid-open publication No. 2014-026747

Disclosure of Invention

[ problems to be solved by the invention ]

In general, in order to reduce the interface resistance between the positive electrode layer or the negative electrode layer and the electrolyte layer, solid battery cells in which the positive electrode layer, the electrolyte layer, and the negative electrode layer are integrated are stacked, and the stacked body is used as one battery. However, when the solid-state battery cells are stacked in the solid-state battery, the current collectors of the metal foils come into contact with each other, and the friction at the contact portion surfaces is small and the solid-state battery cells easily slip. Therefore, the stacked position of the solid battery cells is likely to be displaced or rotated during handling or when an external impact is applied.

In the electrolytic solution battery, since the separator larger than the electrodes is present between the electrodes, short circuit is less likely to occur, and performance degradation due to misalignment is less likely to occur, and therefore, misalignment and rotation of the stacking position of the battery cells are not regarded as a great problem.

If the solid battery cell is displaced or rotated in the stacking position, short circuits are likely to occur when the cell is pressed, or the resistance changes due to the weight of the tightening load, which is not preferable for the performance of the battery. Further, it causes inconvenience in handling, and therefore, brings about a reduction in productivity.

The present invention is directed to prevent the above-described misalignment and rotation of the stacking position of the solid battery cells, thereby ensuring the quality of the solid battery and improving the productivity.

[ means for solving problems ]

A solid-state battery is provided, in which a plurality of solid-state battery cells are repeatedly stacked, each of the solid-state battery cells includes a positive electrode layer, a negative electrode layer, a solid electrolyte layer, and a pair of current collector layers sandwiching the positive electrode layer, one surface of each of the current collector layers is in contact with the positive electrode layer or the negative electrode layer, the other surface of each of the current collector layers is in contact with the current collector layer of the adjacent solid-state battery cell, and the friction coefficient of the other surface of each of the current collector layers is larger than the friction coefficient of the one surface of each of the current collector layers.

In this way, in the stacked body of the solid-state battery, a frictional force against the side slip is generated on the contact surface between the current collectors, and the shift and rotation of the stacked position can be prevented.

The surface roughness of the other surface of the current collector layer may be larger than the surface roughness of the one surface of the current collector layer.

The current collector layer may be composed of a metal foil disposed on the one surface side and a conductive layer disposed on the other surface side.

The aforementioned conductive layer may also be a carbon coating.

The current collector layer may be composed of a metal foil disposed on the one surface side and an adhesive layer having adhesiveness disposed on the other surface side.

(Effect of the invention)

According to the present invention, it is possible to prevent the shift and rotation of the stacking position of the solid-state battery, ensure the quality of the solid-state battery, and improve the productivity.

Drawings

Fig. 1 is a diagram showing an outline of a solid battery cell 10 of the present invention.

Fig. 2 is a diagram showing a solid-state battery 100 in which a plurality of solid-state battery cells of the present invention are stacked.

Fig. 3 is a diagram showing an outline of a laminated body of the solid battery cells 10a of the present invention.

Fig. 4 is a diagram showing an outline of a laminated body of the solid battery cell 10b of the present invention.

Detailed Description

The solid-state battery and the method for manufacturing the same according to the present invention will be described in detail below with reference to the drawings, but the present invention is not limited thereto.

(solid Battery cell)

Fig. 1 is a diagram showing an outline of a solid battery cell 10 of the present invention.

Fig. 2 is a diagram showing a solid-state battery 100 in which a plurality of solid-state battery cells of the present invention are stacked.

The solid-state battery cell 10 of the present invention is configured in a layered structure, and includes a positive electrode layer 13, a negative electrode layer 11, a solid electrolyte layer 15 present between these electrode layers, and further includes a positive electrode current collector 14 for collecting current from the positive electrode and a negative electrode current collector 12 for collecting current from the negative electrode. These layers are constituted as, for example, a negative electrode current collector 12, a negative electrode layer 11, a solid electrolyte layer 15, a positive electrode layer 13, and a positive electrode current collector 14 in this order from the top surface in fig. 1. Further, a plurality of such structures are stacked as the solid battery cells 10, thereby forming the high-capacity solid battery 100.

(Single-sided electrode)

The solid-state battery cell 10 of the present invention is a single-sided electrode, and includes an electrode mixture only on one side of a current collector. Although the single-sided electrode is inferior in energy density to the double-sided electrode having the electrode mixture on both sides of the current collector, it is an electrode excellent in durability and input/output characteristics because it can integrally form the positive electrode layer, the negative electrode layer, and the electrolyte layer and can maintain the formation of a good interface between the positive electrode layer or the negative electrode layer and the electrolyte layer.

(Positive electrode layer)

The positive electrode layer 13 used in the solid-state battery of the present invention is a layer containing at least a positive electrode active material. As the positive electrode active material, a material capable of releasing and storing a charge transfer medium may be appropriately selected. The solid electrolyte may be optionally contained from the viewpoint of improving the conductivity of the charge transfer medium. In addition, a conductive aid may be optionally contained to improve conductivity. Further, from the viewpoint of exhibiting flexibility and the like, a binder may be optionally contained. As the solid electrolyte, the conductive aid, and the binder, a solid electrolyte, a conductive aid, and a binder generally used for solid batteries can be used.

The positive electrode active material may be the same as the positive electrode active material used in the positive electrode active material layer of a general solid-state battery, and is not particularly limited. For example, in the case of a lithium ion battery, a layered active material containing lithium, a spinel-type active material, an olivine-type active material, and the like are exemplified. Specific examples of the positive electrode active material include: lithium cobaltate (LiCoO)₂) Lithium nickelate (LiNiO)₂)、LiNi_pMn_qCo_rO₂(p+q+r＝1)、LiNi_pAl_qCo_rO₂(p + q + r ═ 1), lithium manganate (LiMn)₂O₄) With Li₁+xMn₂-x-yM_yO₄A hetero element represented by (x + y ═ 2, M ═ at least one selected from Al, Mg, Co, Fe, Ni, and Zn) instead of Li — Mn spinel, lithium metal phosphate (LiMPO)₄And M ═ at least one selected from Fe, Mn, Co, and Ni), and the like.

The positive electrode current collector 14 is not particularly limited as long as it has a function of collecting current in the positive electrode layer, and examples thereof include aluminum, aluminum alloys, stainless steel, nickel, iron, titanium, and the like, and among them, aluminum alloys, and stainless steel are preferable. The shape of the positive electrode current collector 14 may be, for example, a foil shape or a plate shape.

(method for producing Positive electrode)

The positive electrode can be produced by disposing a positive electrode mixture containing a positive electrode active material on the surface of a positive electrode current collector. The positive electrode can be produced by the same method as the conventional method, and can be produced by either a wet method or a dry method. Hereinafter, a case of manufacturing a positive electrode by using a wet method will be described.

The positive electrode is manufactured using two steps: obtaining a positive electrode mixture slurry containing a positive electrode mixture and a solvent; and applying the positive electrode mixture slurry to the surface of the positive electrode current collector and drying the positive electrode mixture slurry to form a positive electrode mixture layer on the surface of the positive electrode current collector. For example, a positive electrode mixture slurry can be obtained by mixing and dispersing a positive electrode mixture in a solvent. The solvent used in this case is not particularly limited, and may be appropriately selected depending on the properties of the positive electrode active material, the solid electrolyte, and the like. For example, a nonpolar solvent such as heptane is preferable. As the mixing and dispersion of the positive electrode mixture and the solvent, various mixing and dispersing apparatuses such as an ultrasonic dispersing apparatus, a vibrator, and Filmix (registered trademark) can be used. The solid content in the positive electrode mixture slurry is not particularly limited.

The positive electrode mixture slurry thus obtained is applied to the surface of a positive electrode current collector and dried, and a positive electrode mixture layer is formed on the surface of the positive electrode current collector, whereby a positive electrode can be obtained. As a method of applying the positive electrode slurry to the surface of the positive electrode current collector, a known application method such as a doctor blade may be used. The total thickness of the positive electrode mixture layer and the positive electrode current collector after drying (the thickness of the positive electrode) is not particularly limited, but is preferably 0.1 μm or more and 1mm or less, and more preferably 1 μm or more and 100 μm or less, from the viewpoint of energy density and stacking property, for example. The positive electrode can be produced by any pressing process. The pressure at which the positive electrode is pressed may be about 100 MPa.

(negative electrode layer)

The negative electrode layer 11 used for the solid-state battery of the present invention is a layer containing at least a negative electrode active material. The solid electrolyte may be optionally contained from the viewpoint of improving the conductivity of the charge transfer medium. In addition, a conductive aid may be optionally contained to improve conductivity. Further, from the viewpoint of exhibiting flexibility and the like, a binder may be optionally contained. As the solid electrolyte, the conductive aid, and the binder, a solid electrolyte, a conductive aid, and a binder generally used for a solid battery can be used.

The negative electrode active material is not particularly limited as long as it can store and release a charge transfer medium, and for example, in the case of a lithium ion battery, there are: lithium titanate (Li)₄Ti₅O₁₂) Lithium transition metal oxides; TiO 2₂、Nb₂O₃And WO₃And transition metal oxides; a metal sulfide; a metal nitride; carbon materials such as graphite, soft carbon, and hard carbon; and metallic lithium, metallic indium, lithium alloys, and the like. The negative electrode active material may be in the form of a powder or a film.

The negative electrode current collector 12 is not particularly limited as long as it has a function of collecting current with respect to the negative electrode layer 13. Examples of the material of the negative electrode current collector 12 include nickel, copper, and stainless steel. The shape of the negative electrode current collector 12 may be, for example, foil-like or plate-like.

(method of manufacturing negative electrode)

The negative electrode can be produced by, for example, a process in which a negative electrode mixture slurry prepared by charging a negative electrode active material or the like into a solvent, dispersing the mixture using an ultrasonic dispersing device or the like is applied to the surface of a negative electrode current collector, and then dried, similarly to the positive electrode. The solvent used in this case is not particularly limited, and may be appropriately selected according to the properties of the negative electrode active material and the like. The thickness of the negative electrode is, for example, preferably 0.1 μm or more and 1mm or less, and more preferably 1 μm or more and 100 μm or less. In addition, the negative electrode can be manufactured by a pressing process. The pressure at the time of pressing the anode is preferably 200MPa or more, more preferably about 400 MPa.

(solid electrolyte layer)

Solid electrolyte layer 15 is a layer laminated between positive electrode layer 13 and negative electrode layer 11, and is a layer containing at least a solid electrolyte material. Conduction of a charge transfer medium between the positive electrode active material and the negative electrode active material can be performed via the solid electrolyte material contained in the solid electrolyte layer 15.

The solid electrolyte material is not particularly limited as long as it is a material having charge transfer medium conductivity, and examples thereof include a sulfide solid electrolyte material, an oxide solid electrolyte material, a nitride solid electrolyte material, a halide solid electrolyte material, and the like, and among them, a sulfide solid electrolyte material is preferable. This is because the charge transfer medium conductivity is high as compared with an oxide solid electrolyte material.

As the sulfide solid electrolyte material, for example, in the case of a lithium ion battery, Li is cited₂S-P₂S₅、Li₂S-P₂S₅LiI, etc. Further, the above-mentioned "Li₂S-P₂S₅"description means that the use of a composition containing Li₂S and P₂S₅The sulfide solid electrolyte material obtained from the raw material composition of (1) is the same as described above in other descriptions.

On the other hand, in the case of a lithium ion battery, for example, the oxide solid electrolyte material includes a NASICON type oxide, a garnet type oxide, a perovskite type oxide, and the like. Examples of the NASICON type oxide include oxides containing Li, Al, Ti, P and O (e.g., Li)_1.5Al_0.5Ti_1.5(PO₄)₃). Examples of the garnet-type oxide include oxides containing Li, La, Zr and O (e.g., Li)₇La₃Zr₂O₁₂). Examples of the perovskite-type oxide include oxides containing Li, La, Ti and O (for example, LiLaTiO)₃)。

(method for producing solid electrolyte layer)

The solid electrolyte layer 15 can be produced by a process of pressing a solid electrolyte or the like, for example. Alternatively, the solid electrolyte layer may be produced by applying a solid electrolyte slurry prepared by dispersing a solid electrolyte or the like in a solvent to the surface of the substrate or the electrode. The solvent used in this case is not particularly limited, and may be appropriately selected depending on the properties of the binder and the solid electrolyte. The thickness of the solid electrolyte layer varies greatly depending on the constitution of the battery, and is, for example, preferably 0.1 μm or more and 1mm or less, more preferably 1 μm or more and 100 μm or less.

(coefficient of friction)

If the friction coefficient of the contact surface between the stacked solid battery cells increases, the frictional resistance to the side slip increases, and the shift and rotation of the stacked position are less likely to occur. The friction coefficient is originally a relative measure between two objects in contact and cannot be uniquely determined for only one object, but since the object of the present invention is to compare the magnitude of the friction coefficient of different object groups with respect to a certain same object (adjacent solid battery cells), the friction coefficient with respect to a certain same object (adjacent solid battery cells) is described as being unique to a unique object.

By the processing for increasing the friction coefficient of the other surface of the bipolar collector layer, it is possible to prevent the shift and rotation of the stacking position when the solid-state battery cells are stacked. This processing can be performed by, for example, performing blasting, plating, coating with a conductive paste, coating with a binder, or the like on the current collector, and it is preferable to perform plating using a highly conductive material such as carbon for the plating.

(surface roughness)

By increasing the surface roughness of the other surface of the current collector and increasing the friction coefficient, it is possible to prevent the shift and rotation of the stacking position when stacking the solid battery cells. This is performed, for example, by sandblasting the current collector. The material, particle size, and the like of the sand used for the blasting are not particularly limited as long as the shifting and rotation of the stacked body of the solid battery cells 10a can be prevented. In order to avoid the residual insulating sand from impairing the conductivity of the current collectors of both electrodes, it is preferable to sufficiently remove the sand by ultrasonic cleaning after grinding. The method of adjusting the surface roughness is not limited to the sandblasting method as long as the displacement and rotation of the stacked body of the solid battery cells can be sufficiently prevented.

(formation of conductive layer)

By forming the conductive layer having a large friction coefficient on the surface on the other surface of the current collector, it is possible to prevent the shift and rotation of the stacking position when stacking the solid-state battery cells. Which is performed using, for example, a carbon coating process. The formation pattern and thickness of the carbon-coated conductive layer are not particularly limited as long as the displacement and rotation of the stacked body of the solid battery cells can be prevented, and it is more preferable that the stacked thickness is not excessively large from the viewpoint of energy density. Further, as long as the laminate of the solid battery cells can be prevented from shifting or rotating and has sufficient conductivity, the adjustment of the friction coefficient is not limited to the carbon coating layer, and the coating layer may be formed by applying a conductive paste, for example.

(adhesive layer)

By forming the adhesive layer having adhesiveness on the other surface of the current collector, it is possible to prevent the shift and rotation of the stacking position when stacking the solid-state battery cells. As a method and a material for forming the adhesive layer, an adhesive, a double-sided tape, or the like may be used as long as electrical conduction can be performed between the two collectors, but the adhesive layer more preferably has electrical conductivity. In addition, from the viewpoint of conductivity, it is not necessarily required to form an adhesive layer on the entire surface of the collector surface, and it is sufficient if the shift and rotation of the lamination position can be prevented.

(method of manufacturing solid Battery)

The above-described positive electrode layer, solid electrolyte layer, negative electrode layer, and current collector layer were laminated in the order shown in fig. 1 to produce a solid battery cell 10 of the present invention. After they are laminated, they may be optionally pressed to be integrated. Further, a plurality of such structures are stacked as the solid-state battery cells to form a single body, thereby forming a high-power solid-state battery 100. The solid-state battery 100 may be optionally pressed again to be integrated. This causes the collectors having an increased friction coefficient to come into pressure contact with each other, and the irregularities on the surfaces of the collectors mesh with each other, thereby making it less likely to cause misalignment and rotation of the stacking position.

< embodiment of the invention >

Hereinafter, embodiments of the present invention will be described in detail using examples.

Fig. 3 is a view showing an outline of the laminate of the solid battery cells 10a after the surface roughness of the other surface of the current collector layer is increased to increase the friction coefficient.

The positive electrode current collector 14a and the negative electrode current collector 12a of the solid battery cell 10a have a large surface roughness by grinding the surfaces thereof on the other surfaces by sandblasting.

Since the stacked solid-state battery cells 10a are engaged with the positive electrode current collector 14a and the negative electrode current collector 12a via the irregularities on the contact surfaces, when a force is applied in a direction perpendicular to the stacking direction, a frictional force against side slip is generated. As a result, the shift and rotation of the stacking position of the solid-state battery cells can be prevented.

Fig. 4 is a view showing an outline of a laminate of the solid battery cell 10b in which the conductive carbon coating layer 16 is disposed on the other surface side of the current collector layer and the friction coefficient is increased.

The positive electrode current collector 14b and the negative electrode current collector 12b of the solid battery cell 10b are formed with a carbon coating 16 on the other surface by a carbon coating treatment. At this time, the carbon coating layer 16 has a certain friction coefficient due to the surface having irregularities.

The stacked solid-state battery cells 10b are engaged with the positive electrode current collector 14b and the negative electrode current collector 12b via the fine irregularities of the carbon coating 16 on the contact surfaces thereof, and when a force is applied in a direction perpendicular to the stacking direction, a frictional force against side slip is generated. As a result, the shift and rotation of the stacking position of the solid-state battery cells can be prevented. Further, since the carbon coating 16 has conductivity, it does not prevent electric charges from moving between the collectors when stacked.

Description of the reference numerals

10 solid battery cell

10a solid battery monomer (Sand blasting treatment)

10b solid battery cell (forming surface layer)

11 negative electrode layer

12 negative electrode layer current collector

12a negative electrode layer collector (sandblasting)

12b negative electrode layer Current collector (forming surface layer)

13 Positive electrode layer

14 positive electrode layer collector

14a Positive electrode layer collector (sandblasting treatment)

14b Positive electrode layer Current collector (Forming surface layer)

15 solid electrolyte layer

16 carbon coating

100 laminated battery

2 insulating material

3 Battery case

The claims (modification according to treaty clause 19)

(modification) A solid-state battery having a plurality of solid-state battery cells repeatedly stacked, the solid-state battery cells including a positive-electrode layer, a negative-electrode layer, a solid-state electrolyte layer, and a pair of current collector layers sandwiching them, and,

one surface of the current collector layer is in contact with the positive electrode layer or the negative electrode layer,

the other surface of the current collector layer is in contact with the current collector layer of the adjacent solid battery cell,

the friction coefficient of the other surface of the current collector layer is larger than the friction coefficient of the one surface of the current collector layer,

the current collector layer is composed of a metal foil disposed on the one surface side and a conductive layer disposed on the other surface side.

(deletion)

(deletion)

(modification) the solid-state battery according to claim 1, wherein the aforementioned conductive layer is a carbon coating layer.

(modification) A solid-state battery having a plurality of solid-state battery cells repeatedly stacked, the solid-state battery cells including a positive-electrode layer, a negative-electrode layer, a solid-state electrolyte layer, and a pair of current collector layers sandwiching them, and,

one surface of the current collector layer is in contact with the positive electrode layer or the negative electrode layer,

the other surface of the current collector layer is in contact with the current collector layer of the adjacent solid battery cell,

the friction coefficient of the other surface of the current collector layer is larger than the friction coefficient of the one surface of the current collector layer,

the collector layer is composed of a metal foil disposed on one surface side and an adhesive layer having adhesiveness disposed on the other surface side,

the adhesive layer is formed only on a part of the surface of the metal foil.

Statement or declaration (modification according to treaty clause 19)

Claim 1 modified in this way is to add new technical contents to the present invention, wherein the collector layer is composed of a metal foil disposed on the one surface side and a conductive layer disposed on the other surface side as set forth in claim 3 of the original application.

Claims 2 and 3 are deleted based on this modification.

The modified claim 4 adjusts the reference relationship based on the modification of claim 1.

The modified claim 5 adds a technical content that the adhesive layer is formed only on a part of the surface of the metal foil based on [0037] of the original specification of the present application.