JP7647697B2 - Manufacturing method for all-solid-state batteries - Google Patents

Description

This disclosure relates to a method for manufacturing an all-solid-state battery. In particular, this disclosure relates to a method for manufacturing a stacked type all-solid-state battery.

Lithium-ion batteries are used as small batteries with high energy density. Among lithium-ion batteries, all-solid-state batteries, in which the electrolyte is replaced with a solid electrolyte, are attracting particular attention. This is because all-solid-state batteries use a solid electrolyte instead of the conventional electrolyte, and are expected to further increase energy density.

An all-solid-state battery is manufactured, for example, by stacking a negative electrode collector, a negative electrode active material layer, a solid electrolyte layer, a positive electrode active material layer, and a positive electrode collector in this order to obtain a battery stack. In an all-solid-state battery, lithium ions move between the layers of the battery stack. In order to increase the efficiency of lithium ion movement, it is necessary to increase the adhesion between the layers. For this reason, when manufacturing an all-solid-state battery, it is common to compress the battery stack using a press device and/or a roll press device. In recent years, the use of isotropic pressure application has been considered to further increase the adhesion between the layers of the battery stack.

For example, Patent Document 1 discloses a method for manufacturing an all-solid-state battery that includes applying isotropic pressure to a battery stack.

JP 2019-121558 A

The manufacturing method of an all-solid-state battery disclosed in Patent Document 1 (hereinafter simply referred to as "the manufacturing method of Patent Document 1") discloses that a support plate is laminated on one side of a battery stack and isotropic pressure is applied to it. Patent Document 1 also discloses that when applying isotropic pressure, the battery stack and the support plate are enclosed together in a laminate film container.

In the manufacturing method of Patent Document 1, it was necessary to open the laminate film container after applying isotropic pressure and remove the battery stack and the support plate, which resulted in poor manufacturability. In addition, a large amount of waste laminate film container was generated, which was a cause of increased manufacturing costs. If the battery stack and the support plate were not enclosed together in the laminate film container, the support plate could shift when isotropic pressure was applied. Furthermore, if a support plate was not used, warping occurred in the battery stack after isotropic pressure was applied. Furthermore, when preparing the battery stack, the end faces of each layer of the battery stack were prone to shifting, which could cause a short circuit between the end faces of the positive electrode body and the negative electrode body that constitute the battery stack.

In view of these circumstances, the inventors have found that there is a need for a method for manufacturing an all-solid-state battery that can suppress warping of the battery stack and efficiently increase adhesion between the layers of the battery stack. The inventors have also found that there is a need for a method for manufacturing an all-solid-state battery that can suppress misalignment of the layers of the battery stack when preparing the battery stack and avoid short circuits between the end faces of the positive electrode body and the negative electrode body that constitute the battery stack.

The present disclosure has been made to solve the above problems. That is, the present disclosure aims to provide a method for manufacturing an all-solid-state battery that can suppress warping of the battery stack and efficiently increase adhesion between the layers of the battery stack. It also aims to provide a method for manufacturing an all-solid-state battery that can suppress misalignment of the layers of the battery stack when preparing the battery stack and avoid short circuits between the end faces of the positive electrode body and the negative electrode body.

In order to achieve the above object, the present inventors have conducted intensive research and have completed a method for producing an all-solid-state battery according to the present disclosure. The method for producing an all-solid-state battery according to the present disclosure includes the following aspects.
<1> Encapsulating the battery stack in a laminate film container to obtain an enclosed body;
Laminating support plates on both outer surfaces of the enclosure and sandwiching the enclosure between the support plates; and
applying isotropic pressure to the inclusion body while the inclusion body and the support plate are in contact with each other to compress the inclusion body;
Including,
How solid-state batteries are manufactured.
<2> The method for producing an all-solid-state battery according to <1>, wherein the support plate is clamped with an elastic clip, so that the encapsulant and the support plate are brought into contact with each other by a repulsive force of the elastic clip.
<3> The method for producing an all-solid-state battery according to <1>, further comprising stacking an auxiliary support plate, via an elastic body, on at least one of the outer surfaces of the support plate that sandwiches the encapsulation body, thereby bringing the encapsulation body and the support plate into contact with each other by a repulsive force of the elastic body.
<4> The method for producing an all-solid-state battery according to any one of <1> to <3>, wherein the isotropic pressure is applied in a pressure vessel, and the encapsulation body is sandwiched between the support plates and disposed in the pressure vessel such that a stacking surface of the battery stack is non-horizontal.
<5> Forming a positive electrode active material layer on one or both sides of a positive electrode current collector to prepare a positive electrode layer;
forming a negative electrode active material layer on one or both sides of a negative electrode current collector to prepare a negative electrode layer;
Providing a first solid electrolyte layer and a second solid electrolyte layer; and
preparing the battery stack by contacting the positive electrode active material layer of the positive electrode layer and the negative electrode active material layer of the negative electrode layer via the first solid electrolyte layer and disposing a second solid electrolyte layer on at least one of an end face of the positive electrode layer and an end face of the negative electrode layer;
and when preparing the battery stack, an insulating layer is provided on the outer periphery of the second solid electrolyte layer, and end faces of the layers of the battery stack are aligned at at least two points on the outer periphery of the battery stack, thereby positioning the layers in the stacking direction.
The method for producing the all-solid-state battery according to any one of items <1> to <4>.
<6> Forming a positive electrode active material layer on one or both sides of a positive electrode current collector to prepare a positive electrode layer;
forming a negative electrode active material layer on one or both sides of a negative electrode current collector to prepare a negative electrode layer;
Providing a first solid electrolyte layer; and
preparing the battery stack by contacting the positive electrode active material layer of the positive electrode layer and the negative electrode active material layer of the negative electrode layer via the first solid electrolyte layer;
and when preparing the battery stack, an insulating layer is provided on the outer periphery of the first solid electrolyte layer, and end faces of the layers of the battery stack are aligned at at least two points on the outer periphery of the battery stack, thereby positioning the layers in the stacking direction.
The method for producing the all-solid-state battery according to any one of items <1> to <4>.
<7> Forming a positive electrode active material layer on one or both sides of a positive electrode current collector to prepare a positive electrode layer;
forming a negative electrode active material layer on one or both sides of a negative electrode current collector to prepare a negative electrode layer;
Providing a first solid electrolyte layer and a second solid electrolyte layer; and
preparing a battery stack by contacting the positive electrode active material layer of the positive electrode layer and the negative electrode active material layer of the negative electrode layer via the first solid electrolyte layer and disposing a second solid electrolyte layer on at least one of an end face of the positive electrode layer and an end face of the negative electrode layer;
and when preparing the battery stack, an insulating layer is provided on the outer periphery of the second solid electrolyte layer, and end faces of the layers of the battery stack are aligned at at least two points on the outer periphery of the battery stack, thereby positioning the layers in the stacking direction.
How solid-state batteries are manufactured.
<8> Forming a positive electrode active material layer on one or both sides of a positive electrode current collector to prepare a positive electrode layer;
forming a negative electrode active material layer on one or both sides of a negative electrode current collector to prepare a negative electrode layer;
Providing a first solid electrolyte layer; and
preparing a battery stack by contacting the positive electrode active material layer of the positive electrode layer and the negative electrode active material layer of the negative electrode layer through the first solid electrolyte layer;
and when preparing the battery stack, an insulating layer is provided on the outer periphery of the first solid electrolyte layer, and end faces of the layers of the battery stack are aligned at at least two points on the outer periphery of the battery stack, thereby positioning the layers in the stacking direction.
How solid-state batteries are manufactured.
<9> The method for producing an all-solid-state battery according to <7> or <8>, further comprising applying an isostatic pressure to the battery stack.

According to the present disclosure, when isotropic pressure is applied to the inclusion body, the inclusion body and the support plate are maintained in contact with each other in accordance with the compression of the inclusion body, so that warping of the battery stack after the application of isotropic pressure can be suppressed. In addition, since the outer surface of the inclusion body is sandwiched between the support plate, it is not necessary to remove the support plate from inside the laminate film container after the application of isotropic pressure. From these facts, according to the present disclosure, it is possible to provide a manufacturing method for an all-solid-state battery that can suppress warping of the battery stack and efficiently increase adhesion between each layer of the battery stack. And, by arranging an insulating layer at a predetermined position and positioning the stacking direction at a predetermined place to prepare the battery stack, it is possible to provide a manufacturing method for an all-solid-state battery that can suppress misalignment of each layer of the battery stack and avoid short circuits between the end faces of the positive electrode body and the negative electrode body.

FIG. 1 is an explanatory diagram that illustrates a schematic diagram of an example of an embodiment of the manufacturing method for an all-solid-state battery according to the present disclosure. FIG. 2 is an explanatory diagram that illustrates a schematic diagram of another embodiment of the method for producing an all-solid-state battery according to the present disclosure. FIG. 3 is an explanatory diagram showing a schematic cross section of the enclosure sandwiched between a support plate and an auxiliary support plate in the state shown in FIG. FIG. 4 is an explanatory diagram that illustrates one embodiment of applying isotropic pressure in a pressure vessel in the manufacturing method of an all-solid-state battery according to the present disclosure. FIG. 5 is an explanatory view that illustrates a schematic diagram of another embodiment in which isotropic pressure is applied in a pressure vessel in the manufacturing method of an all-solid-state battery according to the present disclosure. FIG. 6 is a graph showing the height profile and curvature distribution for the all-solid-state battery samples of the examples. FIG. 7 is a graph showing the height profile and curvature distribution for the all-solid-state battery sample of the comparative example. FIG. 8 is an explanatory diagram that illustrates a schematic diagram of an example of a conventional method for manufacturing an all-solid-state battery. FIG. 9 is an explanatory diagram that illustrates a schematic diagram of another example of a conventional method for producing an all-solid-state battery. FIG. 10A is an explanatory diagram that shows a cross section of an example of a method for obtaining a battery stack by forming positive electrode active material layers on both sides of a positive electrode current collector and forming negative electrode active material layers on both sides of a negative electrode current collector. FIG. 10B is an explanatory diagram showing a schematic cross section of a battery stack obtained by the method shown in FIG. 10A. FIG. 11A is an explanatory diagram that shows a cross section of an example of a method for obtaining a battery stack by forming a positive electrode active material layer on one side of a positive electrode current collector and forming negative electrode active material layers on both sides of a negative electrode current collector. FIG. 11B is an explanatory diagram showing a schematic cross section of a battery stack obtained by the method shown in FIG. 11A. FIG. 12A is an explanatory diagram that illustrates a schematic top surface of an example of a positive electrode layer used in the method shown in FIG. 10A. FIG. 12B is an explanatory diagram that illustrates a schematic top surface of an example of a negative electrode layer used in the method shown in FIG. 10A. FIG. 12C is an explanatory diagram that illustrates a schematic top surface of an example of a first solid electrolyte layer used in the method shown in FIG. 10A. FIG. 12D is an explanatory diagram that illustrates a schematic top surface of an example of an insulating layer used in the method shown in FIG. 10A. 12E is an explanatory diagram showing a top view of a positioning method for preparing a battery stack using the positive electrode layer of FIG. 12A, the negative electrode layer of FIG. 12B, the solid electrolyte layer of FIG. 12C, and the insulating layer of FIG. 12D. FIG. 13 is an explanatory diagram showing a top view of another embodiment of the positioning method. FIG. 14 is an explanatory diagram showing a top view of still another embodiment of the positioning method. FIG. 15 is an explanatory diagram showing a cross section of the second solid electrolyte layer, illustrating a method for forming the second solid electrolyte layer that is different from that shown in FIG. 10A. FIG. 16 is an explanatory diagram showing a cross section of an example of an embodiment in which the second solid electrolyte layer is omitted.

Below, an embodiment of the manufacturing method of the all-solid-state battery of the present disclosure will be described in detail. Note that the embodiment described below does not limit the manufacturing method of the all-solid-state battery of the present disclosure.

Without being bound by theory, the following drawings will be used to explain why the manufacturing method for the all-solid-state battery disclosed herein (hereinafter sometimes referred to as the "manufacturing method disclosed herein") can suppress warping of the battery stack and efficiently increase adhesion between the layers of the battery stack.

Isotropic pressure is applied by applying a high-pressure pressure medium to the object. Therefore, when applying isotropic pressure to a battery stack as the object, it is necessary to prevent the battery stack from being damaged or contaminated by the pressure medium. For this reason, the battery stack is enclosed in a laminate film container, and isotropic pressure is applied to the enclosed object.

If a battery stack is enclosed in a laminate film container and isotropic pressure is applied to it, the battery stack will warp. Therefore, by attaching a support plate to the battery stack and applying isotropic pressure to it, warping of the battery stack can be suppressed.

Figure 8 is an explanatory diagram that shows a schematic diagram of an example of a conventional method for manufacturing an all-solid-state battery, and Figure 9 is an explanatory diagram that shows a schematic diagram of another example of a conventional method for manufacturing an all-solid-state battery.

When applying isostatic pressure to the battery stack with a support plate attached, it is necessary to prevent the battery stack from separating from the support plate. Therefore, in the conventional technology, for example, in the manufacturing method of Patent Document 1, the battery stack 10 and the support plate 40 are enclosed together in a laminate film container 20 as shown in FIG. 8. In the example shown in FIG. 8, the battery stack 10 is enclosed in a laminate film container 20, the support plate 40 is attached to the enclosure 30, and the enclosure 30 is further enclosed in a laminate film container 20 to prevent the enclosure 30 from separating from the support plate 40. From the viewpoint of preventing the battery stack 10 from separating from the support plate 40, the support plate 40 may be directly attached to the battery stack 10 as shown in FIG. In the conventional technology, in any case, it was necessary to enclose the battery stack 10 or the enclosure 30 and the support plate 40 together in the laminate film container 20 as shown in FIG. 8 and FIG. 9. Since the support plate 40 is not necessary as a component of the all-solid-state battery, it was necessary to remove the support plate 40 from the laminate film container 20 after applying the isotropic pressure.

The inventors have discovered the following. This discovery will be explained with reference to the drawings. Figure 1 is an explanatory diagram that shows a schematic diagram of an example of an embodiment of the manufacturing method for an all-solid-state battery according to the present disclosure.

In the manufacturing method of the all-solid-state battery of the present disclosure, for example, as shown in FIG. 1, the battery stack 10 is enclosed in a laminate film container 20, and the outer surfaces of both sides of the enclosure 30 are sandwiched by a support plate 40. Then, an isotropic pressure is applied to the enclosure 30 sandwiched by the support plate 40 so that the enclosure 30 and the support plate 40 are maintained in contact even when the enclosure 30 is compressed. To achieve this, a pressure is applied to the support plate 40 in addition to the application of the isotropic pressure so that the enclosure 30 and the support plate 40 are maintained in contact. Specifically, for example, in the embodiment shown in FIG. 1, the enclosure 30 sandwiched by the support plate 40 is further sandwiched by an elastic clip 50. This realizes that the enclosure 30 is compressed by applying an isotropic pressure to the enclosure 30 while the enclosure 30 and the support plate 40 are in contact with each other.

When the enclosure 30 sandwiched between the support plate 40 is further sandwiched between the elastic clip 50, a slight pressure can be applied to the enclosure 30 through the support plate 40 by the elastic clip 50. However, the battery stack 10 in the enclosure 30 is hardly compressed by the pressure applied by the elastic clip 50 alone, and as a result, the layers in the battery stack 10 cannot be sufficiently adhered to each other. Therefore, when the enclosure 30 and the support plate 40 are sandwiched between the elastic clip 50 and an isotropic pressure is applied to them, the enclosure 30 is compressed, and the layers in the battery stack 10 can be sufficiently adhered to each other. At this time, since the support plate 40 is sandwiched between the elastic clip 50, the two sandwiching parts of the elastic clip 50 are separated from each other, and a repulsive force that tries to narrow the gap acts on the support plate 40. Due to this repulsive force, even if the enclosure 30 is compressed when the isotropic pressure is applied, the enclosure 30 and the support plate 40 can be maintained in contact with each other. That is, the inclusion body 30 can be compressed by applying isotropic pressure to the inclusion body 30 while the inclusion body 30 and the support plate 40 are in contact with each other.

In this way, the present inventors have found that by applying isotropic pressure to the enclosure 30 while the enclosure 30 and the support plate 40 are in contact with each other, the support plate 40 does not separate or shift from the enclosure 30 during the application of the isotropic pressure. This makes it possible to avoid separation and/or shifting of the enclosure 30 and the support plate 40, even if the battery stack 10 or the enclosure 30 is not enclosed in the laminate film container 20 together with the support plate 40, as in the manufacturing method of Patent Document 1. This makes it unnecessary to remove the support plate 40 from the laminate film container 20 after the application of the isotropic pressure, as in the manufacturing method of Patent Document 1. In other words, the present inventors have found that warping of the battery stack 10 can be efficiently avoided or suppressed, even if the battery stack 10 or the enclosure 30 is not enclosed in the laminate film container 20 together with the support plate 40, as in the manufacturing technique of Patent Document 1.

The following describes the constituent elements of the manufacturing method for the all-solid-state battery according to the present disclosure, which was completed based on the findings described above.

<<Manufacturing method of all-solid-state batteries>>
The method for producing an all-solid-state battery according to the present disclosure includes an encapsulation body preparation step, an encapsulation body sandwiching step, and an isostatic pressure application step. Each of these steps will be described below.

<Inclusion body preparation step>
First, an enclosure is prepared. Specifically, the battery stack is enclosed in a laminate film container to obtain an enclosure.

A well-known battery stack used in the manufacture of an all-solid-state battery can be selected. A preferred method for forming the battery stack will be described in detail later in "Battery Stack Preparation Process". Such a battery stack is obtained by stacking one or more unit batteries. Typically, the unit battery can be obtained by stacking an anode current collector, an anode active material layer, a solid electrolyte layer, a cathode active material layer, and a cathode current collector in this order. In this case, a well-known anode current collector, an anode active material layer, a solid electrolyte layer, a cathode active material layer, and a cathode current collector for all-solid-state batteries can be selected. Each of these will be described below, but is not limited to this.

Negative electrode current collector For example, Ag, Cu, Au, Al, Ni, Fe, stainless steel, Ti, etc., or alloys thereof can be used as the material of the negative electrode current collector. From the viewpoint of chemical stability, Cu and Ni are preferred, and when a sulfide-based solid electrolyte is used, Ni is particularly preferred from the viewpoint of avoiding sulfidation of the negative electrode current collector.

- Negative electrode active material layer The negative electrode active material layer contains a negative electrode active material, and optionally a solid electrolyte and a binder. The negative electrode active material can be selected from well-known materials having the function of a negative electrode active material of an all-solid-state battery, and is not particularly limited. The negative electrode active material can be selected from materials capable of absorbing and releasing metal ions, such as lithium ions. The negative electrode active material can be selected from, for example, metallic lithium, lithium alloys, carbon materials such as graphite or hard carbon, metallic silicon, silicon alloys, or Li ₄ Ti ₅ O ₁₂ (LTO). These materials may be selected in combination. Examples of lithium alloys include LiSn, LiSi, LiAl, LiGe, LiSb, LiP, and LiIn. Metallic lithium means lithium that is not alloyed. Examples of silicon alloys include alloys with metal elements such as lithium, and may also be alloys with one or more metal elements selected from the group consisting of tin, germanium, and aluminum. Metallic silicon means unalloyed silicon. The negative electrode active material may be selected from other metal materials, such as indium, aluminum, or tin, or a combination thereof. When a graphite material, which is a crystalline carbon material, is selected as the negative electrode active material, the surface of the graphite may be coated with an amorphous coating.

The solid electrolyte may be a sulfide-based amorphous solid electrolyte, such as Li ₂ S-P ₂ S ₅ , Li ₂ O.Li ₂ S.P ₂ S ₅ , Li ₂ S, P ₂ S ₅ , Li ₂ S-SiS ₂ , LiI-Li ₂ S-SiS ₂ , LiI-Li ₂ S-P ₂ S ₅ , LiI-Li ₂ S-P ₂ O ₅ , LiI-LiBr-Li ₂ S-P ₂ S ₅ , LiI-Li ₃ PO ₄ -P ₂ S ₅ , or an oxide-based amorphous solid electrolyte, such as Li ₂ O-B ₂ O ₃ -P ₂ O _{5 ,} Li ₂ O-SiO ₂ , etc.; or oxide-based crystalline solid electrolytes, for example, LiI, Li ₃ N, Li ₅ La ₃ Ta ₂ O ₁₂ , Li ₇ Zr ₂ O ₁₂ , Li ₆ BaLa ₂ Ta ₂ O ₁₂ , Li ₃ PO _(4-3/2w) N _w (w<1), etc.; or sulfide-based crystalline solid electrolytes, for example, glass ceramics such as Li ₇ P ₃ S ₁₁ and Li _3.25 P _0.75 S ₄ , or thio-LiSiO-based crystals such as Li _3.24 P _0.24 Ge _0.76 S ₄ , Li ₆ PS ₅ X (X = Cl, Br) or the like having an argyrodite-type crystal structure (hereinafter, sometimes referred to as "argyrodite-type sulfide solid electrolyte"); or a combination thereof. From the viewpoint of high lithium ion conductivity and electrochemical stability, the argyrodite-type sulfide solid electrolyte is preferred.

There are no particular limitations on the binder as long as it does not adversely affect the performance and manufacture of the all-solid-state battery. The binder may typically be one or more resins selected from the group consisting of fluorine-based resins and polyolefin-based resins, but is not limited thereto. From the viewpoint of dispersibility, fluorine-based resins, particularly polyvinylidene fluoride (PVDF), are preferred. Examples of fluorine-based resins include polyvinylidene fluoride (PVDF), polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP), polytetrafluoroethylene (PTFE), polyvinyl fluoride (PVF), perfluoroalkoxyalkane (PFA), and the like. These may be selected in combination. Examples of polyolefin-based resins include styrene butadiene rubber (SBR), polypropylene (PP), polyethylene (PE), and (meth)acrylic resins such as polymethyl methacrylate (PMMA), polymethyl acrylate, polybutyl acrylate (PBA), and polyacrylonitrile (PAN). You may choose to combine these options.

The negative electrode active material layer may further optionally contain, for example, a binder solvent and a conductive material.

There are no particular limitations on the binder solvent as long as it does not adversely affect the performance and production of the all-solid-state battery. Examples of the binder solvent include butyl butyrate, toluene, and methyl ethyl ketone (MEK), and may be a mixed solvent of these.

The conductive material can be selected from carbon materials such as VGCF (Vapor Grown Carbon Fiber), acetylene black, ketjen black, carbon nanotubes, etc., or combinations thereof.

Solid Electrolyte Layer The solid electrolyte layer contains at least a solid electrolyte, and may optionally contain a binder, etc. Examples of the solid electrolyte used in the solid electrolyte layer include the solid electrolytes described in "Negative Electrode Active Material Layer."

Examples of binders include polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), butylene rubber (BR), styrene-butadiene rubber (SBR), polyvinyl butyral (PVB), acrylic resin, etc. These may be used in combination. Also, heptane, etc., may be used as a solvent for these binders.

Positive electrode active material layer The positive electrode active material layer contains a positive electrode active material, and optionally a conductive material, a binder, and a solid electrolyte. The positive electrode active material can be selected from metal oxides containing lithium and at least one transition metal selected from manganese, cobalt, nickel, and titanium, such as lithium cobalt oxide, lithium nickel oxide, lithium manganate, or lithium nickel cobalt manganate, Li-Mn spinel substituted with a different element, lithium titanate, lithium metal phosphate, or a combination thereof.

As for the conductive material, the conductive material described in "Negative electrode active material layer" can be used. As for the solid electrolyte, the solid electrolyte described in "Negative electrode active material layer" can be used. As for the binder and its solvent, the binder and its solvent described in "Solid electrolyte layer" can be used.

Positive electrode current collector For the positive electrode current collector, reference can be made to the negative electrode current collector described in "Negative electrode current collector." Among them, aluminum is preferred as the positive electrode current collector from the viewpoint of chemical stability.

Method for forming the battery stack The method for forming the battery stack can be a method known in the manufacture of all-solid-state batteries. Below, a typical method for forming the battery stack will be briefly described, but the method is not limited to this.

A unit battery is formed by stacking the negative electrode current collector, the negative electrode active material layer, the solid electrolyte layer, the positive electrode active material layer, and the positive electrode current collector in this order. There is no particular restriction on the stacking method. For example, a solid electrolyte layer is formed on the surface of a base plate, and the solid electrolyte layer side is bonded to one of the negative electrode active material layer and the positive electrode active material layer. Thereafter, the base plate of the solid electrolyte layer is peeled off, and the other of the negative electrode active material layer and the positive electrode active material layer is bonded to the surface of the solid electrolyte layer. A negative electrode current collector and a positive electrode current collector are attached to one side of each of the negative electrode active material layer and the positive electrode active material layer in advance, and the side of the solid electrolyte layer to which the negative electrode current collector and the positive electrode current collector are not attached is bonded.

The unit batteries may be used as the battery stack, or the unit batteries may be stacked and used as the battery stack. After forming the unit batteries and/or stacking the unit batteries, the unit batteries and/or the stack of unit batteries may be pre-pressed using a roll press or the like as desired. As described above, application of isotropic pressure is necessary to improve adhesion between the layers of the battery stack, but pre-pressing can prevent the battery stack from being damaged when the battery stack is enclosed in a laminate film container or the like.

The negative electrode active material layer, solid electrolyte layer, and positive electrode active material layer can be formed by methods well known in the manufacture of all-solid-state batteries. Below, typical methods for forming these are briefly described, but are not limited to these.

The method for forming the negative electrode active material layer involves preparing a negative electrode mixture paste containing a negative electrode active material and, optionally, a solid electrolyte and a binder, applying the negative electrode mixture paste to the surface of the negative electrode current collector, and drying it. The negative electrode mixture paste may further optionally contain a binder solvent and a conductive material. The method for applying the negative electrode mixture is not particularly limited, and examples include a doctor blade method, a metal mask printing method, an electrostatic application method, a dip coating method, a spray coating method, a roll coating method, a gravure coating method, and a screen printing method. These may be used in combination.

The method of forming the solid electrolyte layer includes a method of compressing and molding a powder or pellet of a raw material for forming the solid electrolyte layer containing at least a solid electrolyte. Alternatively, a method of applying a raw material paste for forming the solid electrolyte layer containing at least a solid electrolyte and a solvent to the surface of a base plate and drying the applied paste can be used. The raw material for forming the solid electrolyte layer and the raw material paste for forming the solid electrolyte layer may optionally contain a binder, etc.

The method for forming the positive electrode active material layer involves preparing a positive electrode mixture paste containing at least the positive electrode active material, applying the positive electrode mixture paste to the surface of the positive electrode current collector, and drying it. The positive electrode mixture paste may optionally contain a conductive material, a binder, and a solid electrolyte. The method for applying the positive electrode mixture paste to the surface of the positive electrode current collector can refer to the method for applying the negative electrode mixture paste to the surface of the negative electrode current collector.

The battery stack obtained as described above is enclosed in a laminate film container to obtain an enclosed body. To explain this in the embodiment shown in FIG. 1, for example, the battery stack 10 is enclosed in a laminate film container 20 to obtain an enclosed body 30.

There are no particular limitations on the laminate film container, so long as it is possible to apply isotropic pressure to the battery stack enclosed in the laminate film container. Typically, a well-known laminate film container used in an all-solid-state battery can be used, but is not limited to this. A typical example is an aluminum laminate film container.

<Inclusion body clamping process>
Support plates are laminated on both outer surfaces of the enclosure, and the enclosure is sandwiched between the support plates. This will be described, for example, in the embodiment shown in FIG. 1. Support plates 40 are laminated on both outer surfaces of the enclosure 30, and the enclosure 30 is sandwiched between the support plates 40. The battery stack 10 is formed by laminating an anode current collector, an anode active material layer, a solid electrolyte layer, a cathode active material layer, and a cathode current collector in this order. Here, in the embodiment shown in FIG. 1, the anode current collector, the anode active material layer, the solid electrolyte layer, the cathode active material layer, and the cathode current collector are each laminated approximately horizontally. "Support plates are laminated on both outer surfaces of the enclosure" means that the support plates are laminated in the same manner as the anode current collector, the anode active material layer, the solid electrolyte layer, the cathode active material layer, and the cathode current collector. That is, "support plates are laminated on both outer surfaces of the enclosure and the enclosure is sandwiched between the support plates" means, for example, in the embodiment shown in Fig. 1, that the laminated surfaces of the support plates 40 are substantially horizontal. Therefore, in the embodiment shown in Fig. 1, this means that the long sides (horizontal sides) of the enclosure 30 are sandwiched between the support plates 40, but does not mean, for example, that the short sides (vertical sides) of the enclosure 30 are sandwiched between the support plates 40.

There are no particular limitations on the support plate 40 as long as it does not bend or deform in the isotropic pressure application process described below. It is preferable that the support plate 40 has excellent corrosion resistance against the pressure medium used for applying isotropic pressure. From this viewpoint, it is preferable that the support plate 40 is made of, for example, aluminum, an aluminum alloy, stainless steel, or a combination of these. Also, typically, isotropic pressure is applied in a pressure vessel. If the support plate 40 is made of a material with high rigidity (high Young's modulus) and high strength, even a thin support plate 40 can avoid or suppress bending and deformation when isotropic pressure is applied. If a thin support plate 40 is used, a large number of enclosed bodies 30 sandwiched between the support plates 40 can be loaded into the pressure vessel. From this viewpoint, it is preferable that the support plate 40 is made of, for example, stainless steel.

The thickness of the support plate 40 may be determined appropriately based on the relationship between the type of material of the support plate 40 and the rigidity and strength. The thickness of the support plate 40 may be, for example, 1 mm or more, 2 mm or more, 3 mm or more, 4 mm or more, or 5 mm or more, and may be 20 mm or less, 15 mm or less, 10 mm or less, 8 mm or less, or 6 mm or less.

<Isotropic pressure application step>
While the inclusion body and the support plate are in contact with each other, an isotropic pressure is applied to the inclusion body to compress the inclusion body. As described above, for example, in the embodiment shown in FIG. 1, the inclusion body and the support plate are maintained in contact with each other by the elastic clip 50 when the isotropic pressure is applied, but this is not limited to this. When the inclusion body and the support plate are maintained in contact with each other, a repulsive force of the elastic clip 50 is applied to the support plate 40 in addition to the application of the isotropic pressure. Such a repulsive force may be of a degree sufficient to maintain the inclusion body and the support plate in contact with each other, and may be, for example, 0.001 MPa or more, 0.005 MPa or more, 0.01 MPa or more, 0.05 MPa or more, 0.1 MPa or more, or 0.5 MPa or more, and may be 5 MPa or less, 4 MPa or less, 3 MPa or less, 2 MPa or less, or 1 MPa or less. That is, in addition to the application of isotropic pressure, a pressure is applied to the support plate 40 by the repulsive force of the elastic clip 50 to maintain the contact between the enclosure 30 and the support plate 40 .

Here, an embodiment different from that shown in FIG. 1 will be described. FIG. 2 is an explanatory diagram that shows a schematic diagram of another embodiment of the manufacturing method for an all-solid-state battery according to the present disclosure. FIG. 3 is an explanatory diagram that shows a schematic diagram of a cross section of the encapsulation body 30 sandwiched between support plates 40a, 40b, 40c, and 40d and auxiliary support plate 45 from the state shown in FIG. 2.

As shown in FIG. 3, an auxiliary support plate 45 is further laminated on the outer surface of the support plates 40a, 40b, 40c, and 40d that sandwich the inclusion body 30 via an elastic body 55. As a result, the repulsive force (biasing force) of the elastic body 55 maintains the contact between the support plates 40a, 40b, 40c, and 40d and the inclusion body 30 during the application of isotropic pressure. The repulsive force (biasing force) of the elastic body may be sufficient to maintain the contact between the inclusion body and the support plate, and may be, for example, 0.001 MPa or more, 0.005 MPa or more, 0.01 MPa or more, 0.05 MPa or more, 0.1 MPa or more, or 0.5 MPa or more, and may be 5 MPa or less, 4 MPa or less, 3 MPa or less, 2 MPa or less, or 1 MPa or less. That is, in addition to the application of isotropic pressure, the repulsive force (biasing force) of the elastic body 55 applies pressure to the support plate 40 to maintain the inclusion body 30 in contact with the support plate. The inclusion body 30 shown in FIG. 3 may be considered to be the same as the inclusion body 30 already described. In addition, in the embodiment shown in FIG. 3, the number of inclusion bodies 30 is three, but this is not limited to this.

The battery stack 10 in the enclosure 30 is formed by stacking the negative electrode collector, the negative electrode active material layer, the solid electrolyte layer, the positive electrode active material layer, and the positive electrode collector in this order. Here, for example, in the embodiment shown in FIG. 3, the negative electrode collector, the negative electrode active material layer, the solid electrolyte layer, the positive electrode active material layer, and the positive electrode collector are arranged (stacked) approximately horizontally. "Laminating an auxiliary support plate via an elastic body on at least one of the outer surfaces of the support plate that holds the enclosure" means that the auxiliary support plate is stacked in the same manner as the negative electrode collector, the negative electrode active material layer, the solid electrolyte layer, the positive electrode active material layer, and the positive electrode collector. Therefore, "Laminating an auxiliary support plate via an elastic body on at least one of the outer surfaces of the support plate that holds the enclosure" means that, for example, in the embodiment shown in FIG. 3, the stacking surface of the auxiliary support plate 45 is approximately horizontal. In addition, "at least one side" means that, in the embodiment shown in FIG. 3, the auxiliary support plate is laminated via the elastic body 55 to the upper outer surface (upper surface of the support plate 40d) in FIG. 3, but is not limited to this. In other words, it means that the auxiliary support plate 45 may be laminated via the elastic body 55 to both the upper and lower outer surfaces (both the upper surface of the support plate 40d and the lower surface of the support plate 40a) in FIG. 3.

The auxiliary support plate 45 is further laminated on the outer surfaces of the support plates 40a, 40b, 40c, and 40d that sandwich the enclosure 30 via the elastic body 55, so a repulsive force (biasing force) of the elastic body 55 is generated. However, the repulsive force of the elastic body 55 alone cannot compress the battery stack 10 in the enclosure 30, and the layers in the battery stack 10 cannot be sufficiently adhered to each other. Therefore, if an isotropic pressure is applied while the repulsive force of the elastic body is applied, the enclosure 30 is compressed, and the layers in the battery stack 10 can be sufficiently adhered to each other. At this time, the repulsive force of the elastic body 55 acts on the support plates 40a, 40b, 40c, and 40d separately from the application of the isotropic pressure, so that the abutment between the enclosure 30 and the support plate 40 can be maintained. In other words, isotropic pressure can be applied to the enclosure 30 while the enclosure 30 and the support plate 40 are in abutment.

There is no particular limitation on the method of generating a repulsive force in the elastic body 55 and applying this repulsive force to the support plate 40. For example, in the embodiment shown in FIG. 3, the support plate 40a farthest from the auxiliary support plate 45 and the auxiliary support plate 45 are fixed plates, and the support plates 40b, 40c, and 40d other than the support plate 40a farthest from the auxiliary support plate 45 are movable plates, so that the elastic body 55 generates a repulsive force. In other words, the support plates 40b, 40c, and 40d other than the support plate 40a farthest from the auxiliary support plate 45 move due to the repulsive force of the elastic body 55. As a result, the contact between the encapsulation body 30 and the support plates 40a, 40b, 40c, and 40d can be maintained by the repulsive force of the elastic body 55 during the application of isotropic pressure.

In the embodiment shown in FIG. 3, a bolt 70 is fixed to the support plate 40a farthest from the auxiliary support plate 45, and through holes 42 are formed in the support plates 40b, 40c, and 40d other than the support plate 40a farthest from the auxiliary support plate 45 and the auxiliary support plate 45, and the bolt 70 is inserted through the through hole 42. Then, a nut 72 is fastened on the surface of the auxiliary support plate 45 opposite the support plates 40a, 40b, 40c, and 40d so that the elastic body 55 generates a repulsive force. In this way, the auxiliary support plate 45 and the support plate 40a farthest from the auxiliary support plate 45 can be fixed plates, and the support plates 40b, 40c, and 40d other than the support plate 40a farthest from the auxiliary support plate 45 can be movable plates.

The magnitude of the applied isotropic pressure may be appropriately determined taking into consideration the area of the stacked surfaces of the battery stack 10, etc., so that the layers of the battery stack 10 in the enclosure 30 are sufficiently in close contact with each other. The isotropic pressure may be, for example, 10 MPa or more, 50 MPa or more, 100 MPa or more, 200 MPa or more, 300 MPa or more, or 400 MPa or more, or 1000 MPa or less, 900 MPa or less, 800 MPa or less, 700 MPa or less, 600 MPa or less, or 500 MPa or less.

The temperature at which the isotropic pressure is applied may be appropriately determined so that the layers of the battery stack 10 in the enclosure 30 are sufficiently in close contact with each other and the battery stack 10 is not altered. The temperature at which the isotropic pressure is applied may be, for example, 100°C or higher, 120°C or higher, 140°C or higher, 160°C or higher, 180°C or higher, or 190°C or higher, and may be 300°C or lower, 280°C or lower, 260°C or lower, 240°C or lower, 220°C or lower, or 200°C or lower.

The time for which the isostatic pressure is applied may be appropriately determined so that the layers of the battery stack 10 in the enclosure 30 are sufficiently in close contact with each other. The time for which the isostatic pressure is applied may typically be 0.5 minutes or more, 1 minute or more, 3 minutes or more, or 5 minutes or more, and may be 60 minutes or less, 30 minutes or less, or 10 minutes or less.

A known pressure medium can be used as the pressure medium for applying the isotropic pressure. Examples of the pressure medium include gas, liquid, powder, and combinations thereof. The pressure medium is typically a liquid, and more typically, water, oil, and combinations thereof.

There are no particular limitations on the method of applying isotropic pressure, and known methods can be used. Typically, the object is placed in a pressure vessel, and isotropic pressure is applied to the object in the pressure vessel. In this case, the enclosed body sandwiched between support plates may be placed in the pressure vessel so that the stacking surface of the battery stack is non-horizontal. This will be explained using drawings. FIG. 4 is an explanatory diagram that shows a schematic diagram of one aspect of applying isotropic pressure in a pressure vessel in the manufacturing method of the all-solid-state battery disclosed herein. FIG. 5 is an explanatory diagram that shows a schematic diagram of another aspect of applying isotropic pressure in a pressure vessel in the manufacturing method of the all-solid-state battery disclosed herein.

Figure 4 shows the state in which the enclosure 30 and the like of the embodiment shown in Figures 2 and 3 are loaded into the pressure vessel 60. Due to space limitations, the enclosure 30 and the elastic body 55 are omitted. As shown in Figure 4, typically, the lamination surface of each layer of the battery stack 10 in the enclosure 30 is approximately horizontal, but this is not limited thereto, and the lamination surface may be non-horizontal. For example, as shown in Figure 5, the lamination surface of each layer of the battery stack 10 in the enclosure 30 may be approximately vertical. Note that, like Figure 4, due to space limitations, Figure 5 also omits the enclosure 30 and the elastic body 55. In addition, the embodiment shown in Figure 5 is similar to the embodiment in Figure 4, except that the support plate 40 and the auxiliary support plate 45 are rectangular.

In the manufacturing method of the all-solid-state battery disclosed herein, the encapsulation body 30 and the support plate 40 are kept in contact with each other even during the application of isotropic pressure. Therefore, as in the embodiment shown in FIG. 5, even if the stacking surface is not horizontal, it is possible to avoid or suppress the displacement of the encapsulation body 30. Also, as in the embodiment shown in FIG. 5, even if the cross-sectional area of the loading port (above the pressure vessel 60) of the pressure vessel 60 is smaller than the area of the stacking surface of the battery stack 10 in the encapsulation body 30, the encapsulation body 30 and the like can be loaded into the pressure vessel 60 by making the stacking surface vertical.

<Battery Stack Preparation Process>
The battery stack may be formed as follows. This will be described with reference to the drawings. FIG. 10A is an explanatory diagram showing a cross section of an example of a method for obtaining a battery stack by forming a positive electrode active material layer on both sides of a positive electrode current collector and a negative electrode active material layer on both sides of a negative electrode current collector. FIG. 10B is an explanatory diagram showing a cross section of a battery stack obtained by the method shown in FIG. 10A. FIG. 11A is an explanatory diagram showing a cross section of an example of a case in which a positive electrode active material layer is formed on one side of a positive electrode current collector and a negative electrode active material layer is formed on both sides of a negative electrode current collector to obtain a battery stack. FIG. 11B is an explanatory diagram showing a cross section of a battery stack obtained by the method shown in FIG. 11A.

As shown in FIG. 10A, a positive electrode active material layer 110 is formed on both sides of a positive electrode collector 100 to prepare a positive electrode layer 120, and a negative electrode active material layer 210 is formed on both sides of a negative electrode collector 200 to prepare a negative electrode layer 220. Alternatively, as shown in FIG. 11A, a positive electrode active material layer 110 is formed on one side of a positive electrode collector 100 to prepare a positive electrode layer 120, and a negative electrode active material layer 210 is formed on both sides of a negative electrode collector 200 to prepare a negative electrode layer 220. Then, a first solid electrolyte layer 310 and a second solid electrolyte layer 320 are prepared. As shown in FIG. 11A, when a positive electrode active material layer 110 is formed on one side of a positive electrode collector 100 to prepare a positive electrode layer 120, the positive electrode collectors 100 are brought into contact with each other to obtain a positive electrode layer 120. When preparing the negative electrode layer 220 by forming the negative electrode active material layer 210 on one side of the negative electrode current collector 200, the negative electrode current collectors 200 are brought into contact with each other to obtain the negative electrode layer 220. The materials and formation methods of the positive electrode current collector 100, the positive electrode active material layer 110, the negative electrode current collector 200, the negative electrode active material layer 210, the first solid electrolyte layer 310, and the second solid electrolyte layer 320 are as already described.

In both the embodiments of FIG. 10A and FIG. 11A, the positive electrode active material layer 110 of the positive electrode layer 120 and the negative electrode active material layer 210 of the negative electrode layer 220 are brought into contact with each other via the first solid electrolyte layer 310, and a second solid electrolyte layer is disposed on the end surface of the positive electrode layer 120 to prepare the battery stack 10. In the embodiments of FIG. 10A and FIG. 11A, the outer peripheral edge of the first solid electrolyte layer 310 is folded to form the second solid electrolyte layer 320, but this is not limited to this. Details will be described later.

When preparing the battery stack 10, as shown in Figs. 10A and 11A, an insulating layer 400 is placed on the outer periphery 330 of the second solid electrolyte layer 320, and the battery stack 10 is positioned in the stacking direction (the vertical direction in Figs. 10A and/or 11A) at least at two locations on the outer periphery. There are no particular limitations on the material that constitutes the insulating layer 400, as long as it can insulate electrical conduction. Examples of materials that constitute the insulating layer 400 include glass, mica, and insulating resins, and insulating resins, particularly insulating thermoplastic resins, are preferred from the viewpoint of durability when applying press pressure and/or isotropic pressure.

The positioning in the stacking direction is performed by aligning the end faces of each layer of the battery stack 10 at at least two points on the outer periphery of the battery stack 10. This will be explained using the drawings. FIG. 12A is an explanatory diagram showing a schematic top view of an example of a positive electrode layer used in the method shown in FIG. 10A. FIG. 12B is an explanatory diagram showing a schematic top view of an example of a negative electrode layer used in the method shown in FIG. 10A. FIG. 12C is an explanatory diagram showing a schematic top view of an example of a solid electrolyte layer used in the method shown in FIG. 10A. FIG. 12D is an explanatory diagram showing a schematic top view of an example of an insulating layer used in the method shown in FIG. 10A. FIG. 12E is an explanatory diagram showing the top view of a positioning method when preparing a battery stack using the positive electrode layer of FIG. 12A, the negative electrode layer of FIG. 12B, the solid electrolyte layer of FIG. 12C, and the insulating layer of FIG. 12D.

As shown in FIG. 10A, a positive electrode active material layer 110 is formed on both sides of a positive electrode collector 100 to prepare a positive electrode layer 120. At this time, as shown in FIG. 12A, a part of the positive electrode collector 100 is made to protrude as a positive electrode collector tab 102. Similarly, as shown in FIG. 12B, a part of the negative electrode collector 200 is made to protrude as a negative electrode collector tab 202. For ease of explanation, FIG. 10A shows a cross section at a portion where the positive electrode collector tab 102 and the negative electrode collector tab 202 are not present.

10A, the end faces of each layer of the battery stack 10 are aligned using the positioning jig 500 in FIG. 12E to position each layer of the battery stack 10 in the stacking direction. The end faces of each layer of the battery stack 10 refer to the end faces of each layer exposed to the external shape of the battery stack 10. In the embodiment shown in FIG. 10A, the end faces of each layer exposed to the external shape of the battery stack 10 are the end faces of the negative electrode layer 220, a part of the second solid electrolyte layer 320, and the insulating layer 400. In the following description, the end faces of each layer exposed to the external shape of the battery stack 10 may be simply referred to as the "end faces of each layer."

In the embodiment shown in FIG. 12E, positioning is performed over the entire outer periphery of the battery stack, excluding the positive electrode current collector tab 102 and the negative electrode current collector tab 202 (positioning is performed at multiple points on the outer periphery of the battery stack, excluding the positive electrode current collector tab 102 and the negative electrode current collector tab 202). Therefore, in order to perform this positioning in the embodiment shown in FIG. 12E, the outer shapes of the end faces of each layer exposed to the outer shape of the battery stack 10 are made approximately the same, except for the areas where the positive electrode current collector tab 102 and the negative electrode current collector tab 202 are installed.

In the manufacturing method of the all-solid-state battery of the present disclosure, the positioning method is not limited to the embodiment shown in FIG. 12E (an embodiment in which the positioning is performed over the entire outer periphery of the battery stack, excluding the positive electrode current collector tab 102 and the negative electrode current collector tab 202). FIGS. 13 and 14 are explanatory views showing the top surface of another embodiment of the positioning method. In the embodiment shown in FIG. 13, two abutments 520a, 520b are used to abut the end faces of each layer against these abutments 520a, 520b, thereby aligning the parts of the end faces of each layer that contact the abutments 520a, 520b, and positioning the stacking direction of each layer. The arrangement positions of the two abutments 520a, 520b are not limited to the positions shown in FIG. 13, and may be, for example, the positions shown in FIG. 14. In addition, the number of abutments is not limited to two. That is, in the manufacturing method of the all-solid-state battery of the present disclosure, the stacking direction of each layer may be positioned by aligning the end faces of each layer at at least two places on the outer periphery of the battery stack 10. The positioning points can be determined appropriately depending on the external shape of each layer.

When positioning is performed at two locations, the angle between one positioning surface (e.g., the positioning surface of abutment 520a) and the other positioning surface (e.g., the positioning surface of abutment 520b) is θ. In this case, θ is not 0° or 180° (see FIG. 13), but may be more than 0°, 10° or more, 20° or more, 30° or more, 40° or more, 50° or more, 60° or more, 70° or more, or 80° or more, and is preferably less than 180°, 170° or less, 160° or less, 150° or less, 140° or less, 130° or less, 120° or less, or 100° or less. In the case of the embodiment shown in FIG. 14, θ is 90°. By setting θ to the above-mentioned preferred angle, the misalignment of each layer of the battery stack 10 can be advantageously suppressed in both the vertical and horizontal directions in FIG. 12E.

In this manner, in the embodiment shown in FIG. 10A, the battery stack 10 shown in FIG. 10B is obtained. In the embodiment shown in FIG. 11A, the battery stack 10 shown in FIG. 11B is obtained.

10A and 11A, the second solid electrolyte layer 320 is disposed only on the end surface of the positive electrode layer 120, but the second solid electrolyte layer 320 may be disposed only on the end surface of the negative electrode layer 220. Also, the second solid electrolyte layer 320 may be disposed on both the end surface of the positive electrode layer 120 and the end surface of the negative electrode layer 220.

10A and 11A, the first solid electrolyte layer 310 is in contact with both sides of the positive electrode layer 120, and the outer peripheral edge of both first solid electrolyte layers 310 is folded to form the second solid electrolyte layer 320, but this is not limited to the above. Another method for forming the second solid electrolyte layer 320 will be described with reference to the drawings. FIG. 15 is an explanatory diagram showing a cross section of the second solid electrolyte layer 320, which is formed by a method different from that shown in FIG. 10A.

In FIG. 15, of the two first solid electrolyte layers 310 sandwiching the positive electrode layer 120, the lower first solid electrolyte layer 310 is left as is, and the upper first solid electrolyte layer 310 is folded to form the second solid electrolyte layer 320, and an insulating layer 400 is disposed around the outer periphery of the second solid electrolyte layer 320.

In the embodiment shown in FIG. 11A, the positive electrode active material layer 110 is formed on one side of the positive electrode collector 100 to obtain the positive electrode layer 120, and the negative electrode active material layer 210 is formed on both sides of the negative electrode collector 200 to obtain the negative electrode layer 220, but this is not limited to the above. For example, the positive electrode active material layer 110 may be formed on both sides of the positive electrode collector 100 to obtain the positive electrode layer 120, and the negative electrode active material layer 210 may be formed on one side of the negative electrode collector 200 to obtain the negative electrode layer 220. Alternatively, the positive electrode active material layer 110 may be formed on one side of the positive electrode collector 100 to obtain the positive electrode layer 120, and the negative electrode active material layer 210 may be formed on one side of the negative electrode collector 200 to obtain the negative electrode layer 220.

By using the second solid electrolyte layer 320, disposing the insulating layer 400 on the outer periphery of the second solid electrolyte layer 320, and preparing the battery stack 10 as described above, the following can be achieved. That is, the battery stack 10 can be prepared quickly while suppressing misalignment of the stacking direction of each layer, and short circuits at the ends of the positive electrode layer 120 and the negative electrode layer 220 can be avoided. This is particularly advantageous when the outer shape of the positive electrode layer 120 is smaller than the outer shape of the negative electrode layer 220, or when the outer shape of the negative electrode layer 220 is smaller than the outer shape of the positive electrode layer 120.

Furthermore, the second solid electrolyte layer 320 can be omitted by doing the following. This will be explained using the drawings. Figure 16 is an explanatory diagram showing a cross section of one example of an embodiment in which the second solid electrolyte layer is omitted.

As shown in FIG. 16, the positive electrode active material layer 110 of the positive electrode layer 120 and the negative electrode active material layer 210 of the negative electrode layer 220 are brought into contact with each other through the first solid electrolyte layer 310 to prepare the battery stack 10. At this time, an insulating layer is placed on the outer periphery of the first solid electrolyte layer 310, and the end faces of each layer of the battery stack 10 are aligned at least at two points on the outer periphery of the battery stack 10 to position the stacking direction. The end faces of each layer of the battery stack 10 in this embodiment are the end faces of the positive electrode layer 120, the negative electrode layer 220, and the insulating layer 400. With this embodiment, the battery stack 10 can be prepared at high speed while suppressing the misalignment of the stacking direction of each layer, and a short circuit at the end of the positive electrode layer 120 and the end of the negative electrode layer 220 can be avoided. This embodiment is effective when the outer shape of the positive electrode layer 120 and the outer shape of the negative electrode layer 220 are approximately the same.

Up to now, even if isostatic pressure is applied to the battery assembly prepared in the manner described in the "battery stack preparation process," the adhesion between the layers of the battery stack can be efficiently increased.

Transformation
In addition to what has been described so far, the manufacturing method of the all-solid-state battery of the present disclosure can be modified in various ways within the scope of the claims. For example, the embodiment shown in FIG. 1 and the embodiment shown in FIG. 3 may be implemented simultaneously. Specifically, the clamping body of the embodiment shown in FIG. 1 and the clamping body of the embodiment shown in FIG. 3 may be loaded into the same pressure vessel, and isotropic pressure may be applied to them. Note that the "clamping body" means, for example, the entire enclosure 30 clamped by the support plate 40 and the elastic clip 50 as in the embodiment shown in FIG. 1. Alternatively, it means the entire enclosure 30 clamped by the support plate 40 and the auxiliary support plate 45 as in the embodiment shown in FIG. 3.

The manufacturing method of the all-solid-state battery of the present disclosure will be explained in more detail below with reference to examples and comparative examples. Note that the manufacturing method of the all-solid-state battery of the present disclosure is not limited to the conditions used in the following examples.

<<Preparation of all-solid-state battery samples>>
An all-solid-state battery sample was prepared as follows.

Example 1
1, an isostatic pressure was applied to the enclosure 30. The isostatic pressure was 980 MPa, and the temperature at which the isostatic pressure was applied was 190° C. As the battery stack 10 in the enclosure 30, ten unit batteries were stacked.

Comparative Example
The isostatic pressure was applied to the enclosure 30 as it was. That is, the isostatic pressure was applied to the enclosure 30 without attaching the support plate 40. The conditions for applying the isostatic pressure and the number of stacked unit cells were the same as in the example.

Example 2
An all-solid-state battery sample was prepared in the same manner as in Example 1, except that a battery laminate was prepared in the manner shown in FIG. 10A.

Example 3
An all-solid-state battery sample was prepared in the same manner as in Example 1, except that a battery laminate was prepared in the manner shown in FIG. 16 .

"evaluation"
After the application of the isotropic pressure, the battery stack 10 was removed from the laminate film container 20 of the enclosure 30, and the height profile of the current collector surface (the stack surface of the battery stack 10) was measured. For the measurement, a digital microscope VHX-700 manufactured by Keyence Corporation was used. Then, a quadratic approximation equation was calculated for the measured height profile. From this approximation equation, the curvature at each position was calculated according to the following equation.
Curvature = |d ² y/dx ² |/{1+(dy/dx) ² } ^3/2
Here, x represents the height of the current collector surface, and y represents the position.

The results are shown in Figures 6 and 7. Figure 6 is a graph showing the height profile and curvature distribution for the all-solid-state battery sample of the example. Figure 7 is a graph showing the height profile and curvature distribution for the all-solid-state battery sample of the comparative example.

6 and 7, it can be seen that a substantially constant curvature is obtained in the current collector plane in both the all-solid-state battery samples of the Examples and Comparative Examples. The curvatures are as follows:
Curvature (mm ^-1 )
Example 0.00014
Comparative Example 0.007

From this, it was confirmed that the warping was very small in the all-solid-state battery sample of Example 1 compared to the comparative example. Moreover, it was confirmed that the warping was also very small in the all-solid-state battery samples of Examples 2 and 3, and that the misalignment of the layers of the battery stack was suppressed compared to the all-solid-state battery sample of Example 1, making it even easier to avoid short circuits between the end faces of the positive electrode body and the negative electrode body that constitute the battery stack.

These results confirm the effectiveness of the manufacturing method for the all-solid-state battery disclosed herein.

LIST OF SYMBOLS 10 battery stack 20 laminated film container 30 encapsulation body 40, 40a, 40b, 40c, 40d support plate 42 through hole 45 auxiliary support plate 50 elastic clip 55 elastic body 60 pressure vessel 70 bolt 72 nut 100 positive electrode current collector 102 positive electrode current collector tab 110 positive electrode active material layer 120 positive electrode layer 200 negative electrode current collector 202 negative electrode current collector tab 210 negative electrode active material layer 220 negative electrode layer 310 first solid electrolyte layer 320 second solid electrolyte layer 330 outer periphery 400 insulating layer 500 positioning jig 520a, 520b butting

Claims (9)

encapsulating the battery stack within a laminate film container to obtain an encapsulation;
Laminating support plates on both outer surfaces of the enclosure and sandwiching the enclosure between the support plates; and
applying isotropic pressure to the inclusion body while the inclusion body and the support plate are in contact with each other to compress the inclusion body;
and ​
The magnitude of the isotropic pressure is 10 MPa or more.
How solid-state batteries are manufactured. The method for manufacturing an all-solid-state battery according to claim 1, wherein the support plate is clamped with an elastic clip, and the encapsulant and the support plate are brought into contact with each other by the repulsive force of the elastic clip. The method for manufacturing an all-solid-state battery according to claim 1, further comprising stacking an auxiliary support plate via an elastic body on at least one of the outer surfaces of the support plate that sandwiches the encapsulation body, thereby bringing the encapsulation body and the support plate into contact with each other by the repulsive force of the elastic body. The method for manufacturing an all-solid-state battery according to claim 1 or 2, wherein the isotropic pressure is applied in a pressure vessel, and the encapsulation body sandwiched between the support plates is disposed in the pressure vessel such that the stacking surface of the battery stack is non-horizontal. forming a positive electrode active material layer on one or both sides of a positive electrode current collector to prepare a positive electrode layer;
forming a negative electrode active material layer on one or both sides of a negative electrode current collector to prepare a negative electrode layer;
Providing a first solid electrolyte layer and a second solid electrolyte layer; and
preparing the battery stack by contacting the positive electrode active material layer of the positive electrode layer and the negative electrode active material layer of the negative electrode layer via the first solid electrolyte layer, and disposing a second solid electrolyte layer on at least one of an end face of the positive electrode layer and an end face of the negative electrode layer;
Including ,
When preparing the battery stack, an insulating layer is provided on the outer periphery of the second solid electrolyte layer, and end faces of the layers of the battery stack are aligned at at least two points on the outer periphery of the battery stack, thereby positioning the layers in the stacking direction.
The method for producing the all-solid-state battery according to claim 1 or 2. forming a positive electrode active material layer on one or both sides of a positive electrode current collector to prepare a positive electrode layer;
forming a negative electrode active material layer on one or both sides of a negative electrode current collector to prepare a negative electrode layer;
Providing a first solid electrolyte layer; and
preparing the battery stack by contacting the positive electrode active material layer of the positive electrode layer and the negative electrode active material layer of the negative electrode layer via the first solid electrolyte layer;
Including ,
When preparing the battery stack, an insulating layer is provided on the outer periphery of the first solid electrolyte layer, and end faces of the layers of the battery stack are aligned at at least two points on the outer periphery of the battery stack, thereby positioning the layers in the stacking direction.
The method for producing the all-solid-state battery according to claim 1 or 2. forming a positive electrode active material layer on one or both sides of a positive electrode current collector to prepare a positive electrode layer;
forming a negative electrode active material layer on one or both sides of a negative electrode current collector to prepare a negative electrode layer;
Providing a first solid electrolyte layer and a second solid electrolyte layer; and
preparing a battery stack by contacting the positive electrode active material layer of the positive electrode layer and the negative electrode active material layer of the negative electrode layer via the first solid electrolyte layer, and disposing a second solid electrolyte layer on at least one of an end face of the positive electrode layer and an end face of the negative electrode layer;
Including ,
when preparing the battery stack, an insulating layer is provided on the outer periphery of the second solid electrolyte layer, and the outer shapes of the end faces of each layer exposed to the outer shape of the battery stack are made substantially the same, and the end faces of each layer of the battery stack are aligned over the entire outer periphery of the battery stack, thereby positioning the layers in the stacking direction.
How solid-state batteries are manufactured. forming a positive electrode active material layer on one or both sides of a positive electrode current collector to prepare a positive electrode layer;
forming a negative electrode active material layer on one or both sides of a negative electrode current collector to prepare a negative electrode layer;
Providing a first solid electrolyte layer; and
preparing a battery stack by contacting the positive electrode active material layer of the positive electrode layer and the negative electrode active material layer of the negative electrode layer via the first solid electrolyte layer;
Including ,
when preparing the battery stack, an insulating layer is provided on the outer periphery of the first solid electrolyte layer, and the outer shapes of the end faces of each layer exposed to the outer shape of the battery stack are made substantially the same, and the end faces of each layer of the battery stack are aligned over the entire outer periphery of the battery stack, thereby positioning the layers in the stacking direction.
How solid-state batteries are manufactured. The method for manufacturing an all-solid-state battery according to claim 7 or 8, wherein an isotropic pressure is applied to the battery stack.

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