JP6859234B2 - Manufacturing method of all-solid-state battery - Google Patents

Description

The present disclosure relates to a method for manufacturing an all-solid-state battery.

With the rapid spread of information-related devices such as personal computers, video cameras and mobile phones, and communication devices in recent years, the development of batteries used as their power sources has been emphasized. In addition, the automobile industry and the like are also developing high-output and high-capacity batteries for electric vehicles or hybrid vehicles.
Lithium-ion all-solid-state batteries have a high energy density because they utilize a battery reaction that involves the movement of lithium ions, and as an electrolyte interposed between the positive electrode and the negative electrode, a solid electrolyte is used instead of an electrolyte solution containing an organic solvent. It is attracting attention in that it uses.

Since the active material made of Si-based material has a large theoretical capacity per volume, a lithium ion all-solid-state battery using Si-based material as a negative electrode has been proposed.
In Patent Document 1, an inorganic solid electrolyte _{, an active material represented by the formula (1): Si x} M _(1-x) , and a solid electrolyte composition containing a particle polymer are applied onto a current collector and dried. An all-solid-state secondary battery including the negative electrode active material layer formed by the above-mentioned method is described.

Japanese Unexamined Patent Publication No. 2016-149238

In the all-solid-state secondary battery of Patent Document 1, a binder and a solid electrolyte are contained in the negative electrode together with a Si-based material.
On the other hand, when the binder and the solid electrolyte are not coexisted with the Si-based material in the electrodes of the all-solid-state battery, the contact property between the particles of the Si-based material becomes insufficient, and it becomes difficult to obtain sufficient battery performance.
Therefore, when a Si-based material is used for the electrode of an all-solid-state battery, it is necessary to include a binder or a solid electrolyte in the electrode in order to improve the mutual contact property between the particles of the Si-based material.
However, when a binder or a solid electrolyte coexists with the Si-based material in the electrode of the all-solid-state battery, the Si-based material in the electrode has a large theoretical capacity per volume of the Si-based material itself. Since the content is low, there is a problem that the energy density of the battery as a whole is low.
In view of the above circumstances, an object of the present disclosure is to provide a method for manufacturing an all-solid-state battery having a negative electrode containing a Si-based material as an active material and having a high energy density.

The present disclosure is a method for manufacturing an all-solid-state battery including a positive electrode, a negative electrode, and a solid electrolyte layer arranged between the positive electrode and the negative electrode.
A positive electrode material part containing a positive electrode active material containing Li, a negative electrode material part containing Si single powder as a negative electrode active material and not containing a binder, a conductive material, and a solid electrolyte, and the positive electrode material part and the negative electrode material. A preparatory step for preparing a primary assembly with solid electrolyte material sections arranged between the sections, and
Provided is a method for manufacturing an all-solid-state battery, which comprises a pressurizing step of pressurizing the primary assembly at a pressure of 98 MPa or more in the arrangement direction of the positive electrode material portion, the solid electrolyte material portion, and the negative electrode material portion.

According to the present disclosure, there is provided a method for manufacturing an all-solid-state battery having a negative electrode containing a Si-based material as an active material and having a high energy density.

It is a figure which conceptually shows the primary assembly in the manufacturing method of the all-solid-state battery of this disclosure. It is a figure which conceptually shows the all-solid-state battery obtained by the manufacturing method of this disclosure. It is a figure which shows the battery capacity with respect to the number of charge / discharge cycles of the all-solid-state battery manufactured in Example 1. FIG.

The present disclosure is a method for manufacturing an all-solid-state battery including a positive electrode, a negative electrode, and a solid electrolyte layer arranged between the positive electrode and the negative electrode.
A positive electrode material part containing a positive electrode active material containing Li, a negative electrode material part containing Si single powder as a negative electrode active material and not containing a binder, a conductive material, and a solid electrolyte, and the positive electrode material part and the negative electrode material. A preparatory step for preparing a primary assembly with solid electrolyte material sections arranged between the sections, and
Provided is a method for manufacturing an all-solid-state battery, which comprises a pressurizing step of pressurizing the primary assembly at a pressure of 98 MPa or more in the arrangement direction of the positive electrode material portion, the solid electrolyte material portion, and the negative electrode material portion.

The manufacturing method includes the following aspect.
A method for manufacturing an all-solid-state battery including a positive electrode, a negative electrode, and a solid electrolyte layer arranged between the positive electrode and the negative electrode.
A positive electrode material layer containing a positive electrode active material containing Li, a negative electrode material layer containing Si single powder as a negative electrode active material and not containing a binder, a conductive material, and a solid electrolyte, and the positive electrode material layer and the negative electrode material. A preparatory step to prepare a primary assembly with solid electrolyte material layers arranged between the layers, as well as
A method for manufacturing an all-solid-state battery, comprising a pressurizing step of pressurizing the primary assembly at a pressure of 98 MPa or more in the stacking direction of the positive electrode material layer, the solid electrolyte material layer, and the negative electrode material layer.

The manufacturing method of the present disclosure comprises a Si-based material having a large theoretical capacity per volume by using a negative electrode material portion containing Si single particles as the negative electrode active material and not containing a binder, a conductive material, and a solid electrolyte. Since the negative electrode containing the negative electrode active material at a high density is formed, an all-solid-state battery having a high energy density of the battery as a whole can be obtained.
Further, in the above-mentioned manufacturing method of the present disclosure, the primary assembly is pressurized at a pressure of 98 MPa or more in the arrangement direction of the positive electrode material portion, the solid electrolyte material portion and the negative electrode material portion contained in the primary assembly. It is possible to form an interface between the Si powder and the solid electrolyte so that Li ions can be easily supplied from the solid electrolyte to Si. As a result, an all-solid-state battery that can be charged / discharged even at a low restraint pressure of about 7 MPa can be produced during charging / discharging.
In the negative electrode containing Si single powder and not containing the binder, the conductive material, and the solid electrolyte, the Si particles are in point contact with each other, so unless the battery reaction of the first first layer in contact with the solid electrolyte occurs. It is considered that the subsequent battery reaction at the Si / Si interface after the second layer does not proceed.
According to the manufacturing method of the present disclosure, when Li ions are inserted into the first layer Si particles in contact with the solid electrolyte, the Si particles expand to fill the gaps between the particles, thereby filling the gaps between the particles to form the second layer. Since it becomes possible to make contact with the Si particles, it is not necessary to continue applying a large pressure during charging and discharging if the pressure is first applied by screwing, etc., and it is presumed that the battery reaction proceeds in a chain reaction even with a low binding force. To. It is presumed that this is a phenomenon unique to materials such as Si, which has a large volume change when Li ions are inserted.
Therefore, the all-solid-state battery obtained by the manufacturing method of the present disclosure does not need to be continuously pressurized at a high pressure in order to be charged and discharged, so that a pressurizing jig for continuously applying pressure during charging and discharging is not required. , It is possible to increase the substantial volumetric energy density when considering the battery package as a whole.

A. Schematic of the manufacturing method The manufacturing method of the all-solid-state battery of the present disclosure will be described with reference to FIGS. 1 and 2.
First, as shown in FIG. 1, a positive electrode material portion 3 containing a positive electrode active material containing Li, and a negative electrode material portion 2 containing Si single powder as a negative electrode active material and not containing a binder, a conductive material, and a solid electrolyte. , And a preparatory step for preparing the primary assembly 101 including the solid electrolyte material portion 1 arranged between the positive electrode material portion and the negative electrode material portion. The primary assembly 101 has an array structure in which the positive electrode material portion 3, the solid electrolyte material portion 1, and the negative electrode material portion 2 are arranged in this order.
Next, FIG. 2 is performed by performing a pressurizing step of pressurizing the primary assembly 101 in the arrangement direction of the positive electrode material portion 3, the solid electrolyte material portion 1 and the negative electrode material portion 2 at a pressure of 98 MPa or more. As shown in the above, an all-solid-state battery (positive electrode-solid electrolyte layer-negative electrode aggregate) 102 having a positive electrode 6, a negative electrode 5, and a solid electrolyte layer 4 bonded between the positive electrode 6 and the negative electrode 5 is obtained.

B. Preparation Step (1) Negative Electrode Material Part In the manufacturing method of the present disclosure, the negative electrode material part contains Si single powder as the negative electrode active material, does not contain a binder, a conductive material, and a solid electrolyte, and if necessary, other parts. Contains ingredients. From the viewpoint of increasing the energy density of the battery, the negative electrode material portion may contain only Si simple substance powder.
The particles of Si simple substance constituting the Si simple substance powder _{usually have an average particle size (D 50} ) in the range of 10 nm or more and 50 μm or less, and further in the range of 50 nm or more and 5 μm or less. If the average particle size of the particles is too small, the handleability may be poor, and if the average particle size of the particles is too large, it may be difficult to obtain a flat negative electrode material portion. From the viewpoint of sufficiently increasing the contact property between the Si simple substance particles, the average particle size of the Si simple substance particles may be 1 μm or less, particularly 100 nm or less.
The ratio of Si single powder in the negative electrode material portion is not particularly limited, but from the viewpoint of filling as much active material as possible, it is, for example, 50% by mass or more, and is within the range of 60% by mass or more and 100% by mass or less. It may be in the range of 70% by mass or more and 100% by mass or less, and may be 100% by mass.

The material for forming the negative electrode material portion (finally, the material for forming the negative electrode), that is, the negative electrode mixture, typically contains only Si simple substance powder from the viewpoint of increasing the energy density of the battery. However, if necessary, it may contain a component other than the Si simple substance powder, and for example, it may contain a component that is removed during the formation of the negative electrode material portion.
Examples of the components contained in the negative electrode mixture but removed during the formation of the negative electrode material include a solvent and a removable binder.
As a removable binder, it functions as a binder when forming a negative electrode mixture layer, but it is decomposed or volatilized and removed by firing the negative electrode mixture layer, and does not contain a binder. A binder material that can be used as the negative electrode material portion can be used. Examples of such a removable binder include polyvinyl butyral and acrylic resin.

Examples of the method for forming the negative electrode material portion include a method of pressure molding a powder of a negative electrode mixture containing Si simple substance powder.
When the powder of the negative electrode mixture containing Si simple substance powder is pressure-molded, a press pressure of about 1 MPa or more and 400 MPa or less is usually applied.
As another method, for example, the binder is formed by pressure-molding the powder of the negative electrode mixture containing the Si single powder and the removable binder to form the negative electrode mixture layer, and then firing the binder. A method for removing the negative electrode, or a dispersion of the negative electrode mixture containing Si single powder, a solvent, and a removable binder is applied on the solid electrolyte material part or on another support, dried, and the negative electrode mixture is dried. Examples thereof include a method of removing the binder by firing after forming the layer.

(2) Positive Electrode Material Part The positive electrode material part contains a positive electrode active material containing Li, and if necessary, contains other components such as a binder, a solid electrolyte, and a conductive material.
In the present disclosure, the positive electrode active material containing Li is not particularly limited as long as it is an active material containing a Li element, and is not limited to Li in a simple substance state, and may be a lithium compound. Any substance that functions as a positive electrode in the battery chemical reaction in relation to the counter electrode and promotes the battery chemical reaction accompanied by the movement of Li ions can be used as a positive electrode active material, and can be used as a positive electrode active material of a conventional lithium ion battery. Known substances can also be used in this disclosure.
Examples of the positive electrode active material include elemental lithium metals, lithium alloys, and lithium-containing metal oxides. As the lithium alloy, for example, an In-Li alloy or the like can be used. Examples of the lithium-containing metal oxide include rock salt layered active materials _{such as LiCoO 2} , LiNiO ₂ , LiVO ₂ , LiNi _1/3 Co _1/3 Mn _1/3 O _{2 , LiMn 2} O ₄ , Li (Ni _{0). .5} Mn _1.5) spinel active material _{O 4} or the _like, can be cited LiFePO _4, LiMnPO _4, LiNiPO 4, LiCoPO olivine active material such as _4.
The shape of the positive electrode active material is not particularly limited, but may be in the form of a film or particles.
The ratio of the positive electrode active material in the positive electrode material portion is not particularly limited, but may be, for example, 50% by mass or more, 60% by mass or more and 100% by mass or less, and 70% by mass or more. It may be in the range of 100% by mass or less.

As the binder, for example, polyvinylidene fluoride (PVdF), polytetrafluoroethylene (PTFE), butylene rubber (BR), styrene-butadiene rubber (SBR), polyvinyl butyral (PVB), acrylic resin and the like can be used. it can.
Examples of the conductive material include carbon materials such as acetylene black, ketjen black, and carbon fiber.
The solid electrolyte may be any of a solid electrolyte crystal, an amorphous solid electrolyte, and a solid electrolyte glass ceramics, and the same solid electrolyte as that used in the solid electrolyte material portion described later can be used.

The material for forming the positive electrode material portion (finally, the material for forming the positive electrode), that is, the positive electrode mixture may further contain a component that is removed during the formation of the positive electrode material portion. ..
Examples of the components contained in the positive electrode mixture but removed during the formation of the positive electrode material include a solvent that can be contained in the negative electrode mixture and components similar to the removable binder. ..
Examples of the method for forming the positive electrode material portion include the same method as the method for forming the negative electrode material portion.

(3) Solid Electrolyte Material Part The solid electrolyte material part contains a solid electrolyte and, if necessary, contains other components.
Examples of the solid electrolyte include oxide-based solid electrolytes having high Li ion conductivity, sulfide-based solid electrolytes, and the like.
Examples of the oxide-based solid electrolyte include Li _6.25 La ₃ Zr ₂ Al _0.25 O ₁₂ , Li ₃ PO ₄ , Li _{3 + x} PO _4-x N _x (LiPON), and the like. Examples of the solid electrolyte include Li ₇ P ₃ S ₁₁ , Li ₃ PS ₄ , Li ₈ P ₂ S ₉ , Li ₁₃ GeP ₃ S ₁₆ , Li ₁₀ GeP ₂ S _{12, and the} like.
A powdered solid electrolyte may be used as the solid electrolyte for forming the solid electrolyte material portion, and in that case, the average particle size (D ₅₀ ) of the solid electrolyte particles constituting the powder is usually 10 nm or more and 50 μm or less. It is within the range, and further within the range of 50 nm or more and 10 μm or less.

As the solid electrolyte, one kind alone or two or more kinds can be used. When two or more kinds of solid electrolytes are used, two or more kinds of solid electrolytes may be mixed, or two or more layers of each solid electrolyte may be formed to form a multilayer structure.
When the solid electrolyte has a two-layer structure, for example, the sulfide-based solid electrolyte may be arranged on the positive electrode side and the oxide-based solid electrolyte may be arranged on the negative electrode side, or vice versa. Any arrangement may be used as long as it corresponds to the potential window of the solid electrolyte.
The ratio of the solid electrolyte in the solid electrolyte material portion is not particularly limited, but may be, for example, 50% by mass or more, 60% by mass or more and 100% by mass or less, and 70% by mass or more. It may be in the range of 100% by mass or less, or may be 100% by mass.
Examples of other components contained in the solid electrolyte material portion include binders, plasticizers, dispersants and the like.

Examples of the method for forming the solid electrolyte material portion include a method of pressure molding a powder of a solid electrolyte material containing a solid electrolyte and, if necessary, other components. When the powder of the solid electrolyte material is pressure-molded, a press pressure of about 1 MPa or more and 400 MPa or less is usually applied as in the case of pressure-molding the powder of the negative electrode mixture.
As another method, a cast film formation method using a solution or dispersion of a solid electrolyte and a solid electrolyte material containing other components as needed can be performed.

(4) Primary Assembly In the present disclosure, in the primary assembly, the positive electrode material portion, the solid electrolyte material portion, and the negative electrode material portion are arranged in this order and joined directly or via a portion made of another material. Further, the side opposite to the position where the solid electrolyte material part exists on the positive electrode material part (outside side of the positive electrode material part) and the position opposite to the position where the solid electrolyte material part exists on the negative electrode material part. An aggregate of each part having an arrangement structure in which a part made of another material may be joined to one or both sides of one side (outer side of the negative electrode material part) (positive electrode material part-solid electrolyte material part). -Negative electrode material part aggregate).
The primary assembly may be provided with a portion made of another material as long as it can be uniformly pressurized in the pressurizing step described later. A coating layer such as LiNbO ₃ , Li ₄ Ti ₅ O ₁₂ , or Li ₃ PO ₄ may be provided between the positive electrode material portion and the solid electrolyte material portion, and the negative electrode material portion and the solid electrolyte material portion may be provided. A similar coating layer may be provided between them.
For example, a current collector or an exterior body may be attached to either one or both of the outer side of the positive electrode material portion and the outer side of the negative electrode material portion before the pressurizing step described later.
In the primary assembly, typically, the positive electrode material portion, the negative electrode material portion, and the solid electrolyte material portion arranged between the positive electrode material portion and the negative electrode material portion are directly bonded to each other, and the positive electrode material is formed. It is an aggregate having an arrangement structure in which a portion made of another material is not joined to either the outer side of the portion or the outer side of the negative electrode material portion.

As one embodiment of the method for producing the primary assembly, the solid electrolyte is formed by powder pressure molding of the solid electrolyte material using the powder of the solid electrolyte material, the powder of the negative electrode material, and the powder of the positive electrode material. The material part is formed, and the powder pressure molding of the powder of the negative electrode material on one surface of the solid electrolyte material part, and the positive electrode material on the surface opposite to the surface on which the negative electrode material of the solid electrolyte material part is formed. This is a method of sequentially performing powder pressure molding of the powder of.
In this case, the press pressure when the powder of the solid electrolyte material, the powder of the negative electrode material, and the powder of the positive electrode material are pressure-molded is usually about 1 MPa or more and 600 MPa or less.

Further, as another embodiment of the method for producing the primary assembly, for example, powder of a negative electrode material containing Si single powder is put into a pressure cylinder for powder pressure molding and deposited to a uniform thickness. To form a negative electrode material powder deposit layer.
A solid electrolyte powder and, if necessary, a powder of a solid electrolyte material containing other components are put on the negative electrode material powder deposit layer and deposited to a uniform thickness to form a solid electrolyte material powder layer.
On the solid electrolyte material powder layer, powder of a material containing a positive electrode active material containing Li is put and deposited to a uniform thickness to form a positive electrode material powder layer.
Then, the primary assembly may be produced by pressure-molding the powder deposits having the three powder deposit layers thus formed at one time.

Further, the solid electrolyte material part, the negative electrode material part, and the positive electrode material part may be manufactured by a method other than powder pressure molding. For example, the solid electrolyte material portion may be formed by a cast film forming method using a solution or dispersion of a solid electrolyte material containing a solid electrolyte. The negative electrode material part and the positive electrode material part formed a coating film by applying, for example, a powder of the negative electrode material or a powder of the positive electrode material, and a dispersion liquid containing a removable binder on the solid electrolyte material part. After that, the coating film is heated to remove the binder from the coating film, or the powder of the negative electrode material or the powder of the positive electrode material and the powder containing the removable binder are pressure-molded. After forming the shape of the positive electrode material portion or the negative electrode material portion, the molded body may be formed by a method of heating to remove the binder from the coating film.
Further, the negative electrode material portion and the positive electrode material portion may be formed on a support other than the solid electrolyte material portion. In that case, the negative electrode material portion and the positive electrode material portion are peeled from the support, and the peeled negative electrode material portion or the positive electrode material portion is joined onto the solid electrolyte material portion.

C. Pressurization Step In the manufacturing method of the present disclosure, the pressurization step is a step of pressurizing the primary assembly at a pressure of 98 MPa or more in the arrangement direction of the positive electrode material portion, the solid electrolyte material portion, and the negative electrode material portion.

The pressure applied to the primary assembly may be 98 MPa or more, but may be 400 MPa or less from the viewpoint of preventing lamination inside the all-solid-state battery.
If the applied pressure is not sufficient, the particles of the Si-based material may not be sufficiently adhered to each other, making it difficult to charge and discharge the battery.

The method of pressurizing the primary assembly is not particularly limited, and examples thereof include a method of applying pressure using a flat plate press, a roll press, or the like.

D. All-solid-state battery The primary assembly becomes an all-solid-state battery through the above-mentioned "C. pressurization step". A typical configuration of an all-solid-state battery is a positive electrode-solid electrolyte layer-negative electrode assembly.
In the positive electrode-solid electrolyte layer-negative electrode assembly, the positive electrode, the solid electrolyte layer and the negative electrode are arranged in this order and bonded directly or via a portion made of another material, and the solid electrolyte layer on the positive electrode is further formed. On one or both sides of the side opposite to the position where the solid electrolyte layer exists (outside the positive electrode) and the side opposite to the position where the solid electrolyte layer exists on the negative electrode (outside the negative electrode), the other. It is an aggregate of each part having an arrangement structure in which parts made of a material may be joined.
The thickness of each of the positive electrode and the negative electrode of the positive electrode-solid electrolyte layer-negative electrode aggregate is usually about 0.1 μm or more and 100 μm or less, and the thickness of the solid electrolyte layer is usually about 0.1 μm or more and about 1 mm or less.
Other members such as a current collector and an exterior body may be attached to the all-solid-state battery of the present disclosure.
The all-solid-state battery of the present disclosure may be in a state in which Li ions can be inserted into the negative electrode active material and discharged by energization (charging) thereafter.
Therefore, the all-solid-state battery in the present disclosure is a concept including a state before the first charge.
In the present disclosure, the restraining pressure during charging of the all-solid-state battery is not particularly limited and can be usually about 1 MPa or more and 600 MPa or less, but from the viewpoint of increasing the volumetric energy density of the battery, it may be less than 98 MPa. It may be as low as 7 MPa.

(Synthesis of solid electrolyte A)
In a glove box under an argon atmosphere, Li ₂ S and P ₂ S ₅ were mixed so as to have a molar ratio of 4: 1 to obtain a raw material composition. Next, 1 g of the raw material composition was placed in a zirconia pot (45 ml) together with zirconia balls (5 mmφ, 80 pieces), and the pot was completely sealed (argon atmosphere). This pot was attached to a planetary ball mill machine (P7 manufactured by Fritsch Japan Co., Ltd.), and mechanical milling was performed at a base rotation speed of 500 rpm for 20 hours. As a result, a powder _{of Li 8} P ₂ S ₉ was obtained as the solid electrolyte A.

(Preparation of solid electrolyte B)
_{As the solid electrolyte B, a sintered body of Li 6.25} La ₃ Zr ₂ Al _0.25 O ₁₂ (manufactured by Toyoshima Seisakusho) having a diameter of φ10 mm and a thickness of 0.5 mm was used.

(Example 1)
[Preparation process]
1. 1. First, 150 mg of solid electrolyte A powder was added to a cylinder made of polyethylene terephthalate (PET ^{) and pressed at 3.5 ton / cm 2} (≈343 MPa) to form a solid electrolyte material portion.
2. As the positive electrode active material of the all-solid-state battery, a LiIn foil in which Li foil (manufactured by Honjo Chemical Co., Ltd.) was attached to In foil (φ10 mm manufactured by Niraco Co., Ltd., thickness 0.1 mm) was used. The LiIn foil is placed on one surface of the solid electrolyte material portion, and subsequently, a powder of Si alone as a negative electrode active material (average particle size 100 nm manufactured by Alpha aesar) is placed on the other surface of the solid electrolyte material portion. , The addition amount per unit area was 0.9 mg / cm ² .
Then, the negative electrode material part, the solid electrolyte material part, and the positive electrode material part (LiIn foil) were combined to obtain a primary assembly.
[Pressure process]
The obtained primary assembly was pressed at 1 ton / cm ² (≈98 MPa) to obtain an all-solid-state battery.

(Example 2)
[Preparation process]
1. 1. First, 150 mg of powder of solid electrolyte A was added to a cylinder made of PET ^{, pressed at 3.5 ton / cm 2} (≈343 MPa), and then a sintered body of solid electrolyte B (φ10 mm × t0.5 mm) was added. The solid electrolyte material part was formed by arranging it in a PET cylinder.
2. Prepare a positive electrode material part (LiIn foil) in which Li foil (manufactured by Honjo Chemical Co., Ltd.) is attached to In foil (φ10 mm manufactured by Niraco Co., Ltd., thickness 0.1 mm), place it on the surface of the solid electrolyte A side, and then solid A powder of Si alone (manufactured by Alpha aesar, with an average particle size of 100 nm), which is a negative electrode active material, was deposited ^{on the surface of the electrolyte B side with an addition amount of 0.6 mg / cm 2 per unit area.}
Then, the positive electrode material part (LiIn foil), the solid electrolyte material part (solid electrolyte A, solid electrolyte B), and the negative electrode material part were combined to obtain a primary assembly.
[Pressure process]
The obtained primary assembly was pressed at 5 ton / cm ² (≈490 MPa) to obtain an all-solid-state battery.

(Comparative Example 1)
An all-solid-state battery was obtained in the same manner as in Example 1 except that the primary assembly obtained in the above [preparation step] was not pressed at 98 MPa in the pressurizing step.

[Charge / discharge test]
A charge / discharge test was performed using the all-solid-state batteries obtained in Examples 1 and 2 and Comparative Example 1.
The charge / discharge test was performed on the all-solid-state batteries of Example 1 and Comparative Example 1 in a low confining pressure state by applying a confining pressure of 7 MPa in the stacking direction by screwing with a torque of 0.4 Nm. It was.
On the other hand, the all-solid-state battery of Example 2 was subjected to a charge / discharge test in a state of high restraint pressure by applying a restraint pressure of 100 MPa in the stacking direction by screwing with a torque of 6 Nm. The results are shown in Table 1.

[Charge / discharge test results]
As shown in Table 1, it was found that charging / discharging is possible in Examples 1 and 2.
FIG. 3 is a diagram showing the battery capacity for 1 to 7 cycles of charging and discharging of the all-solid-state battery manufactured in Example 1.
As shown in FIG. 3, it can be seen that in the first embodiment, the battery capacity is stabilized by charging and discharging for about 5 to 6 cycles.
On the other hand, in Comparative Example 1, Li ions could hardly be inserted into the Si-containing negative electrode, and charging was impossible.
^{In Comparative Example 1, constant current (CC) charging is performed at a current density of 0.1 mA / cm 2} until the voltage reaches 0.01 V, and then constant voltage (CV) charging is performed at the obtained voltage for 10 hours. However, the current density was only 1 ^{μA / cm 2.} It is presumed that this is because the primary assembly was not pressed in the pressurizing process.

From the above results, the all-solid-state battery obtained by the manufacturing method of the present disclosure does not need to be continuously pressurized at a high pressure in order to be charged and discharged as a battery. No tools are required, and the actual volumetric energy density when considering the battery package as a whole can be increased.

1 Solid electrolyte material part (solid electrolyte material layer)
2 Negative electrode material part (negative electrode material layer)
3 Positive electrode material part (positive electrode material layer)
4 Solid electrolyte layer 5 Negative electrode 6 Positive electrode 101 Primary assembly 102 All-solid-state battery

Claims (1)

A method for manufacturing an all-solid-state battery including a positive electrode, a negative electrode, and a solid electrolyte layer arranged between the positive electrode and the negative electrode.
A positive electrode material part containing a positive electrode active material containing Li, a negative electrode material part containing Si single powder as a negative electrode active material and not containing a binder, a conductive material, and a solid electrolyte, and the positive electrode material part and the negative electrode material. A preparatory step for preparing a primary assembly with solid electrolyte material sections arranged between the sections, and
A method for manufacturing an all-solid-state battery, which comprises a pressurizing step of pressurizing the primary assembly at a pressure of 98 MPa or more in the arrangement direction of the positive electrode material portion, the solid electrolyte material portion, and the negative electrode material portion.

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