JP2021163759A - Method for manufacturing solid-state battery sheet and method for manufacturing laminate to be used for the same - Google Patents

Abstract

To provide a method for manufacturing a solid-state battery sheet capable of achieving excellent battery performance when used in a solid-state battery, and a method for manufacturing a laminate to be used in the method for manufacturing a solid-state battery sheet.SOLUTION: A method for manufacturing a solid-state battery sheet includes a step of preparing a first member M1 having a first support layer 11 and a first solid electrolyte layer 13, a step of preparing a second member M2 having a second support layer 12 and a second solid electrolyte layer 14, a step of obtaining a first laminate body 1A from the first member M1 and the second member M2 so that the first solid electrolyte layer 13 and the second solid electrolyte layer 14 face each other via a porous base material 10, and a step of pressing the laminate 1A in the thickness direction to form a solid-state battery sheet 5A. In the solid-state battery sheet 5A, at least a part of the first solid electrolyte layer 13 and at least a part of the second solid electrolyte layer 14 are filled in pores H of the porous base material 10 and are in contact with each other.SELECTED DRAWING: Figure 1

Description

The present invention relates to a method for manufacturing a sheet for a solid-state battery. The present invention also relates to a method for manufacturing a laminate used in a method for manufacturing a sheet for a solid-state battery.

Since the solid-state battery does not use a flammable organic solvent, the safety device can be simplified, the manufacturing cost and productivity are excellent, and the voltage can be increased by stacking in series in the cell. It also has features. Since the solid electrolyte used in the solid-state battery does not move other than lithium ions, it is expected to lead to improvement in safety and durability, such as no side reaction due to the movement of anions.

Solid electrolyte sheets are used in the manufacture of solid-state batteries. For example, Patent Document 1 describes a method for producing a solid electrolyte sheet having a porous substrate.

JP-A-2018-129307

As a method for producing a solid electrolyte sheet provided with a porous substrate, there is a method of adhering a solid electrolyte material to the porous substrate and filling it (for example, Patent Document 1). However, for a solid-state battery using the solid electrolyte sheet obtained by the method, further improvement in battery performance is required.

Therefore, the present invention describes a method for manufacturing a solid-state battery sheet that can exhibit good battery performance when used in a solid-state battery, and a method for manufacturing a laminate used in the method for manufacturing the solid-state battery sheet. The purpose is to provide.

In order to solve the above problems, the present invention provides the following methods.
[1] A method for manufacturing a first solid-state battery sheet.
The method is the following step:
(1a) Step of preparing a porous substrate;
(1b) A step of preparing a first member including a first support layer and a first solid electrolyte layer provided on one surface side of the first support layer;
(1c) A step of preparing a second member including a second support layer and a second solid electrolyte layer provided on one surface side of the second support layer;
(1d) The first member and the second member are laminated via the porous base material so that the first solid electrolyte layer and the second solid electrolyte layer face each other. (1e) The step of pressing the first laminate in the thickness direction to form the first solid-state battery sheet.
In the first solid-state battery sheet, at least a part of the first solid electrolyte layer and at least a part of the second solid electrolyte layer are filled in the pores of the porous base material and come into contact with each other. Yes, the method.
[2] A method for manufacturing a second solid-state battery sheet.
The method is the following step:
(2a) Step of preparing the first porous base material and the second porous base material;
(2b) A step of preparing a first member including a first support layer and a first solid electrolyte layer provided on one surface side of the first support layer;
(2c) A step of preparing a second member including a second support layer and a second solid electrolyte layer provided on one surface side of the second support layer;
(2d) A step of laminating the first porous base material on the surface of the first member on the side of the first solid electrolyte layer to obtain a third member;
(2e) A step of laminating the second porous base material on the surface of the second member on the side of the second solid electrolyte layer to obtain a fourth member;
(2f) The third member and the fourth member are placed on the surface of the third member on the side of the first porous base material and the surface of the fourth member on the side of the second porous base material. A step of laminating so as to face the surfaces to obtain a second laminate; and (2 g) a step of pressing the second laminate in the thickness direction to form the second solid-state battery sheet. Including
In the second solid-state battery sheet, at least a part of the first solid electrolyte layer and at least a part of the second solid electrolyte layer are the first porous substrate and the second porous. The method described above, wherein the pores of the substrate are filled and in contact with each other.
[3] A method for producing the first laminate according to the above [1], wherein the following steps:
(3a) Step of preparing a porous substrate;
(3b) A step of preparing a first member including a first support layer and a first solid electrolyte layer provided on one surface side of the first support layer;
(3c) A step of preparing a second member including a second support layer and a second solid electrolyte layer provided on one surface side of the second support layer; and (3d) the first. And the second member are laminated via the porous substrate so that the first solid electrolyte layer and the second solid electrolyte layer face each other to obtain a first laminate. The method described above.
[4] The method for producing the second laminate according to the above [2], wherein the following steps:
(4a) Step of preparing the first porous base material and the second porous base material;
(4b) A step of preparing a first member including a first support layer and a first solid electrolyte layer provided on one surface side of the first support layer;
(4c) A step of preparing a second member including a second support layer and a second solid electrolyte layer provided on one surface side of the second support layer;
(4d) A step of laminating the first porous base material on the surface of the first member on the side of the first solid electrolyte layer to obtain a third member;
(4e) A step of laminating the second porous base material on the surface of the second member on the side of the second solid electrolyte layer to obtain a fourth member; and (4f) the third member and The fourth member is laminated so that the surface of the third member on the first porous substrate side and the surface of the fourth member on the second porous substrate side face each other. The method comprising the step of forming a second laminate.

According to the present invention, there is provided a method for manufacturing a solid-state battery sheet capable of exhibiting good battery performance when used in a solid-state battery, and a method for manufacturing a laminate used in the method for manufacturing the solid-state battery sheet. Will be done.

FIG. 1 is a schematic process diagram showing a method for manufacturing a laminate and a solid-state battery sheet according to the first embodiment of the present invention. FIG. 2A is a schematic process diagram showing a method for manufacturing a laminate and a solid-state battery sheet according to a second embodiment of the present invention. FIG. 2B is a schematic process diagram (continuation of FIG. 2A) showing a method for manufacturing a laminate and a solid-state battery sheet according to a second embodiment of the present invention. FIG. 3A is a plan view of the laminated body formed by the method for producing the laminated body according to the first embodiment and the second embodiment of the present invention. FIG. 3B is a cross-sectional view taken along the line AA of FIG. 3A. FIG. 4 is a schematic view of an apparatus used in the method for manufacturing a laminate according to the first embodiment of the present invention. FIG. 5A is a plan view of a solid-state battery sheet formed by the method for manufacturing a solid-state battery sheet according to the first embodiment and the second embodiment of the present invention. FIG. 5B is a cross-sectional view taken along the line AA of FIG. 5A. FIG. 6 is a schematic view of an apparatus used in the method for manufacturing a solid-state battery sheet according to the first embodiment of the present invention.

≪Manufacturing method of laminated body≫
Hereinafter, embodiments of the method for producing a laminate according to the present invention will be described with reference to FIGS. 1 to 3. 1 (a) to 1 (d) are schematic process diagrams showing steps 3a to 3d in the method for manufacturing a laminate according to the first embodiment of the present invention, and FIGS. 2A to 2B are shown in FIGS. 2A to 2B. (F) is a schematic process diagram showing steps 4a to 4f in the method for manufacturing a laminate according to a second embodiment of the present invention, and FIG. 3A shows the laminates 1A and 1B obtained in steps 3d and 4f. It is a plan view, and FIG. 3B is a cross-sectional view taken along the line AA of FIG. 3A. In each drawing, X indicates the length direction, Y indicates the width direction Y, and Z indicates the thickness direction. The length direction X, the width direction Y, and the thickness direction Z are orthogonal to each other. The length direction X corresponds to the machine direction (MD) at the time of manufacturing the laminates 1A and 1B.

<First Embodiment>
As shown in FIGS. 1A to 1D, the method for producing the laminated body 1A according to the first embodiment of the present invention includes the following steps:
(3a) Step of preparing the porous base material 10;
(3b) A step of preparing a first member M1 including a first support layer 11 and a first solid electrolyte layer 13 provided on one surface side of the first support layer 11;
(3c) A step of preparing a second member M2 including a second support layer 12 and a second solid electrolyte layer 14 provided on one surface side of the second support layer 12; and (3d). The first member M1 and the second member M2 are laminated via the porous base material 10 so that the first solid electrolyte layer 13 and the second solid electrolyte layer 14 face each other to obtain a laminated body 1A. Includes steps.

The execution order of the steps 3a, 3b and 3c is not particularly limited. Step 3d is performed after steps 3a, 3b and 3c.

According to the first embodiment of the present invention, since the method for manufacturing the laminate includes steps 3a to 3d, a solid-state battery sheet capable of exhibiting good battery performance when used for a solid-state battery is manufactured. It is possible to form a laminated body for this purpose. The following are presumed as the reasons for achieving such an effect.

Conventionally, as a method for producing a laminate in which a porous base material and a solid electrolyte layer are laminated, a solid electrolyte layer is formed on the porous base material by applying or dipping the solid electrolyte to the porous base material. There is a method of obtaining a laminate (for example, Patent Document 1). However, when the solid electrolyte is attached to the porous substrate by coating or dipping, the surface of the solid electrolyte layer in the obtained laminate may be uneven. Due to this unevenness, when observing the cross section of the solid electrolyte layer in the thickness direction, a through hole may be formed that leads from the surface side on which the positive electrode layer is arranged to the surface side on which the negative electrode layer is arranged. Such through holes may cause a short circuit in the battery. In addition, the following are presumed as the causes of the above-mentioned through holes. First, when forming the solid electrolyte layer, when the slurry containing the solid electrolyte and the solvent is dried to remove the solvent, the volume of the solvent may shrink, but the solid electrolyte may be applied to the porous substrate. In the case of immersion, it is presumed that the cause is that such volume shrinkage becomes remarkable.

Therefore, as a result of repeated studies on the above problems, the present inventors have focused on a step of adhering a solid electrolyte to a porous substrate by coating or dipping, and have reached the present invention. That is, when the present inventors obtain a laminated body by laminating a preformed solid electrolyte layer on a porous base material, and then attach the solid electrolyte to the porous base material by coating or dipping to obtain a laminated body. Compared to the above, it is possible to suppress through-holes generated in the solid electrolyte layer formed on the porous substrate, and the thickness of the laminate obtained by laminating the pre-formed solid electrolyte layer on the porous substrate is thick. It was newly found that by pressing in the direction, through-holes generated in the solid electrolyte layer filled in the porous substrate can be suppressed. Therefore, according to the first embodiment of the present invention, it is possible to suppress voids generated in the solid electrolyte layer formed on the porous base material and through holes generated in the solid electrolyte layer filled in the porous base material. As a result, it is possible to suppress the occurrence of a short circuit when the solid-state battery sheet obtained by using the laminate is used for the solid-state battery, and as a result, the battery performance of the solid-state battery sheet can be improved. It is presumed that it can be done.

<Step 3a>
Step 3a is a step of preparing the porous base material 10 as shown in FIG. 1 (a).

The porous base material 10 is preferably a base material capable of imparting self-supporting property and strength to the solid electrolyte layer. The porous base material 10 may have a single-layer structure or a multi-layer structure.

The "base material" in the porous base material 10 includes a plate shape, a foil shape, a sheet shape, a film shape, a mesh shape, and the like. When the porous base material 10 is in the form of a sheet, the porous base material may be, for example, a fiber sheet. The fiber sheet is a structure in which fibers are molded into a sheet shape. Examples of the fiber sheet include non-woven fabrics, woven fabrics, knitted fabrics, and papers. When the porous base material 10 is in the form of a film, the porous base material may be, for example, a microporous film.

The "porous" in the porous substrate 10 refers to a state having a large number of pores. The porous base material 10 has pores H such that the first solid electrolyte layer 13 and the second solid electrolyte layer 14 are filled and come into contact with each other when the solid-state battery sheet described later is formed. It may be composed of a plurality of fibrous materials. That is, as shown in FIG. 1A, the porous base material 10 has pores H that communicate from one surface side to the other surface side of the porous base material 10 inside or on the surface. The size of the pores H may be such that at least a part of the first solid electrolyte layer 13 and the second solid electrolyte layer 14 is filled when the solid-state battery sheet described later is formed. The pores H in the porous substrate 10 may be, for example, micropores, mesopores, or macropores. The pores H may communicate with each other. When the porous base material 10 is a fiber sheet, "porous" refers to a state having voids generated in the gaps between the fibers.

In the examples of the present invention, a fiber sheet (nonwoven fabric) is used as the porous base material 10 as described later. Hereinafter, the non-woven fabric will be described as an example of the fiber sheet.

For non-woven fabric, depending on the type of fiber used for manufacturing the non-woven fabric (fiber length, fiber diameter, fiber material, etc.), the type of manufacturing method (for example, web forming method, web fiber bonding method, etc.), etc. , There are various types of non-woven fabrics. The non-woven fabric used as the porous base material 10 is not particularly limited as long as a desired laminate or a sheet for a solid-state battery can be obtained. Examples of the non-woven fabric include fiber orthogonal non-woven fabric, long-fiber non-woven fabric, short-fiber non-woven fabric, wet non-woven fabric, dry non-woven fabric, air-laid non-woven fabric, card-type non-woven fabric, parallel non-woven fabric, cloth non-woven fabric, random non-woven fabric, spunbond non-woven fabric, melt blown non-woven fabric, and flash. Spun non-woven fabric, chemical bond non-woven fabric, water flow entanglement non-woven fabric, needle punch non-woven fabric, stitch bond non-woven fabric, thermal bond non-woven fabric, burst fiber non-woven fabric, tow open weave non-woven fabric, split fiber non-woven fabric, composite non-woven fabric, laminated non-woven fabric, coated non-woven fabric, laminated non-woven fabric, etc. However, among these, a cloth-type non-woven fabric is preferable. The cloth-type non-woven fabric is preferable because it is easy to adjust the strength ratio in the length direction X and the width direction Y, the basis weight (basis weight), and the like. The strength ratio of the cloth-type non-woven fabric in the length direction X and the width direction Y is preferably adjusted uniformly. The basis weight of the cloth-type non-woven fabric may be a low basis weight or a high basis weight. Examples of the cloth-type non-woven fabric include polyolefin mesh cloth (see JP-A-2007-259734). The specific basis weight (basis weight) of the non-woven fabric can be the same as that described in JP-A-2018-129307, for example, and thus the description thereof is omitted here.

The material, porosity, air permeability, thickness, and the like constituting the porous base material 10 can be the same as those of the porous base material used for a general solid-state battery sheet. For example, since it can be the same as the porous substrate described in JP-A-2018-129307, the description here is omitted.

<Step 3b>
Step 3b is a step of preparing the first member M1 as shown in FIG. 1 (b).

The first member M1 has, for example, a sheet shape.

As shown in FIG. 1B, the first member M1 includes a first support layer 11 and a first solid electrolyte layer 13 provided on one surface side of the first support layer 11. ..

As shown in FIG. 1B, the first member M1 further includes an electrode layer (positive electrode layer) 15 provided between the first support layer 11 and the first solid electrolyte layer 13. May be good. The positive electrode layer 15 is a layer provided as needed and can be omitted. The present invention also includes an embodiment in which the positive electrode layer 15 is omitted. Further, the present invention includes an embodiment in which one of the positive electrode layer 15 and the negative electrode layer 16 described later is provided, an embodiment in which both are provided, and an embodiment in which both are omitted. When the positive electrode layer 15 is provided between the first support layer 11 and the first solid electrolyte layer 13, the first support layer 11 preferably has a function as a positive electrode current collector. This is because the first support layer 11 has a function as a positive electrode current collector, so that the solid-state battery sheet obtained by using the laminated body 1A can be used as a solid-state battery.

When forming the laminate 1A, the first support layer 11 supports the first solid electrolyte layer 13 and the positive electrode layer 15. When forming the solid-state battery sheet using the laminate 1A, the first support layer 11 presses the first solid electrolyte layer 13 by the force applied to the first support layer 11, and the first solid electrolyte layer 13 is pressed. At least a part of the solid electrolyte layer 13 is filled in the pores H of the porous base material 10. Further, the first support layer 11 may be used as a positive electrode current collector as described above, or may be peeled off from a solid-state battery sheet described later if necessary. The material, thickness, and the like of the first support layer 11 can be appropriately selected in consideration of the role, function, and the like of the first support layer 11. Examples of the first support layer 11 include a metal layer made of a single metal, a resin layer made of a resin such as a thermoplastic resin and a thermosetting resin, and the like. When the first support layer 11 has a function as a positive electrode current collector, the material, thickness, and the like of the first support layer may be determined by, for example, the positive electrode current collector used in a general solid-state battery. It can be the same as the material, thickness, etc.

The first solid electrolyte layer 13 is formed on the surface of the positive electrode layer 15 (when the positive electrode layer 15 is omitted, the surface of the first support layer 11). As a method for forming the first solid electrolyte layer 13, a general method for forming the solid electrolyte layer can be adopted, and the method is not particularly limited. Examples of the method for forming the first solid electrolyte layer 13 include a method in which the solid electrolyte is dissolved in a solvent, coated on the surface of the positive electrode layer 15 or the surface of the first support layer 11 and dried. Be done.

The first solid electrolyte layer 13 contains at least a solid electrolyte, and may contain a binder if necessary. The first solid electrolyte layer 13 may contain one kind of solid electrolyte, or may contain two or more kinds of solid electrolytes. The "solid electrolyte" is powdery or granular. The content of the solid electrolyte in the first solid electrolyte layer 13 is not particularly limited, but is, for example, 50% by mass or more, preferably 70% by mass or more, more preferably 90% by mass, based on the mass of the first solid electrolyte layer 13. % Or more. The upper limit is 100% by mass.

The solid electrolyte can be appropriately selected from the solid electrolytes generally used for solid-state batteries (for example, all-solid-state lithium-ion batteries). Examples of the solid electrolyte include a sulfide solid electrolyte, an oxide solid electrolyte, a nitride solid electrolyte, a halide solid electrolyte and the like. In the present invention, it is preferable to use a sulfide solid electrolyte. Since the sulfide solid electrolyte is soft, it is excellent in filling the pores H of the porous base material 10.

Examples of the sulfide solid electrolyte include general sulfide solid electrolytes, for example, solid electrolytes containing lithium element, phosphorus element and sulfur element. Further, the sulfide solid electrolyte is preferably made of a material having an algyrodite type crystal structure from the viewpoint of further improving the lithium ion conductivity. Other detailed explanations of the sulfide solid electrolyte can be the same as those described in, for example, Japanese Patent No. 6595153, WO2019 / 00228, Japanese Patent Application Laid-Open No. 2018-067552, and the like. The description in is omitted.

The thickness of the first solid electrolyte layer 13 takes into consideration the filling property of the solid electrolyte in the pores H of the porous base material 10, the amount of the solid electrolyte filled in the pores H of the porous base material 10, and the like. Can be adjusted as appropriate. The thickness of the first solid electrolyte layer 13 is such that when a part of the first solid electrolyte layer 13 is filled in the pores H of the porous base material 10, the remainder of the first solid electrolyte layer 13 (first). The portion of the solid electrolyte layer 13 of the above that was not filled in the pores H of the porous base material 10) is adjusted so as to retain the morphology of the layer. The thickness of the first solid electrolyte layer 13 is, for example, 0.1 μm or more and 1000 μm or less.

When the positive electrode layer 15 is provided between the first support layer 11 and the first solid electrolyte layer 13, the positive electrode layer 15 is formed on the first support layer 11. The method for forming the positive electrode layer 15 can be a general method for forming the positive electrode layer, and is not particularly limited. Examples of the method for forming the positive electrode layer 15 include a method including a step of applying a positive electrode mixture containing a positive electrode active material to the surface of the first support layer 11 and drying the positive electrode layer 15.

The positive electrode layer 15 contains a positive electrode active material, and may contain a solid electrolyte, a conductive auxiliary agent, a binder, and the like, if necessary. The positive electrode layer 15 may contain one kind of positive electrode active material, or may contain two or more kinds of positive electrode active materials. The positive electrode active material can be appropriately selected from positive electrode active materials generally used for solid-state batteries (for example, all-solid-state lithium-ion batteries). Examples of the positive electrode active material include metal oxides and metal sulfides. The thickness of the positive electrode layer is, for example, 0.1 μm or more and 1000 μm or less.

<Step 3c>
Step 3c is a step of preparing the second member M2 as shown in FIG. 1 (c).

As shown in FIG. 1 (c), the second member M2 includes a second support layer 12 and a second solid electrolyte layer 14 provided on one surface side of the second support layer 12. ..

As shown in FIG. 1C, the second member M2 further includes an electrode layer (negative electrode layer) 16 provided between the second support layer 12 and the second solid electrolyte layer 14. May be good. The negative electrode layer 16 is a layer provided as needed and can be omitted. The present invention also includes an embodiment in which the negative electrode layer 16 is omitted. When the negative electrode layer 16 is provided between the second support layer 12 and the second solid electrolyte layer 14, the second support layer 12 preferably has a function as a negative electrode current collector. This is because the second support layer 12 has a function as a negative electrode current collector, so that the solid-state battery sheet obtained by using the laminated body 1A can be used as a solid-state battery.

The description of the second support layer 12 will be omitted because it is the same as that of the first support layer 11. The material constituting the second support layer 12, the thickness of the second support layer 12, and the like may be the same as or different from those of the first support layer 11. When the second support layer 12 has a function as a negative electrode current collector, the material and thickness of the second support layer 12 are, for example, the material and thickness of the negative electrode current collector used in a general solid-state battery. It can be the same as the electrode. Examples of the negative electrode current collector include copper foil.

The description of the second solid electrolyte layer 14 will be omitted because it is the same as that of the first solid electrolyte layer 13. The material constituting the second solid electrolyte layer 14, the thickness of the second solid electrolyte layer 14, and the like may be the same as or different from those of the first solid electrolyte layer 13.

The negative electrode layer 16 contains a negative electrode active material, and may contain a solid electrolyte, a conductive auxiliary agent, a binder, and the like, if necessary. The negative electrode layer 16 may contain one kind of negative electrode active material, or may contain two or more kinds of negative electrode active materials. The negative electrode active material can be appropriately selected from the negative electrode active materials generally used for all-solid-state lithium-ion batteries. Examples of the negative electrode active material include carbon materials, metal materials, silicon-based materials and the like.

Since the other description of the second member M2 is the same as the description of the first member described above, the description here is omitted.

<Step 3d>
In step 3d, as shown in FIG. 1D, the first member M1 and the second member M2 are passed through the porous base material 10 to the first solid electrolyte layer 13 and the second solid electrolyte layer 14. This is a step of obtaining a laminated body 1A by laminating so as to face each other.

As shown in FIG. 3, the laminate 1A obtained in step 3d includes a first support layer 11, a positive electrode layer 15, a first solid electrolyte layer 13, a porous base material 10, and a second solid. The electrolyte layer 14, the negative electrode layer 16, and the second support layer 12 are provided in this order. The positive electrode layer 15 and the negative electrode layer 16 are layers provided as needed and can be omitted. The present invention also includes embodiments in which the positive electrode layer 15 and / or the negative electrode layer 16 are omitted.

The stacking order of the porous base material 10, the first member M1 and the second member M2 is such that the porous base material 10 is located between the first solid electrolyte layer 13 and the second solid electrolyte layer 14. It is not particularly limited as long as it is laminated on. For example, the porous base material 10 may be laminated on the second member M2 and then the first member M1 may be laminated, or the porous base material 10 may be laminated on the first member M1 and then the second member M1 is laminated. The member M2 may be laminated, or the first member M1 and the second member M2 may be laminated on the porous base material 10 at the same time.

The productivity of the laminated body 1A in the case where the porous base material 10, the first member M1 and the second member M2 prepared in advance are laminated to form the laminated body 1A is the first solid electrolyte layer 13 and the first solid electrolyte layer 13 and the first. One of the solid electrolyte layers 14 of 2 is formed on one surface side of the porous base material 10, and then the other of the first solid electrolyte layer 13 and the second solid electrolyte layer 14 is formed on the other side of the porous base material 10. It is superior to the productivity of the laminated body 1A in the case of forming the laminated body 1A on the surface side of the above. Further, when the porous base material 10, the first member M1 and the second member M2 prepared in advance are laminated to form the laminated body 1A, the production of the laminated body 1A is performed by a roll-to-roll method as described later. Can be done with.

In step 3d, if necessary, the laminate 1A may be pressed in the thickness direction. The press can be performed by, for example, a roll press. The press here refers to a press having a lower pressure than the press in step 1e of the method for manufacturing a solid-state battery sheet, which will be described later. Specifically, a part of the first solid electrolyte layer 13 filled in the pores H of the porous base material 10 and the second solid electrolyte layer 14 filled in the pores H of the porous base material 10. It is preferable that the pressure is such that a part of the above does not come into contact with the porous substrate 10.

A part of the first solid electrolyte layer 13 and the second solid electrolyte layer 14 may be filled in the pores H of the porous base material 10 to the extent that they do not come into contact with each other in the porous base material 10. .. Here, "to the extent that both (a part of the first solid electrolyte layer 13 and the second solid electrolyte layer 14) do not come into contact with each other in the porous base material 10" means the first in the porous base material 10. This includes not only the case where the solid electrolyte layer 13 and the second solid electrolyte layer 14 of the above are not completely contacted, but also the case where they are slightly contacted unintentionally.

The laminate 1A is in close contact between the porous base material 10 and the first solid electrolyte layer 13 and / or between the porous base material 10 and the second solid electrolyte layer 14, if necessary. It may have an adhesive layer for improving the property. The adhesive layer may be formed on at least one surface of the porous base material 10, or in the above-mentioned steps 3b and / or step 3c, the adhesive layer is different from the first support layer 11 of the first solid electrolyte layer 13. It may be formed on the opposite surface and / or on the surface of the second solid electrolyte layer 14 opposite to the second support layer 12. The material and forming method of the adhesive layer can be the same as the material and forming method of the general adhesive layer. For example, since the contents can be the same as those described in JP-A-2018-129307, the description here is omitted.

<Roll-to-roll method>
The laminate 1A is preferably manufactured by a roll-to-roll method. By the roll-to-roll method, the laminated body 1A can be continuously manufactured, and the productivity of the laminated body 1A can be improved.

Hereinafter, an embodiment in which the laminated body 1A is manufactured by a roll-to-roll method will be described with reference to FIG. FIG. 4 is a schematic view of the device used in this embodiment.

As shown in FIG. 4, the porous base material 10 may be continuously supplied from the supply reel 101 and continuously wound by the take-up reel 50 to be conveyed. During transport, the porous substrate 10 may be guided by a guide roll. The feed reel 101 is rotatably supported, and the porous substrate 10 may be wound around the feed reel 101.

As shown in FIG. 4, the first support layer 11 may be continuously supplied from the supply reel 111 and conveyed by being continuously wound by the take-up reel 50. During transport, the first support layer 11 may be guided by a guide roll. The supply reel 111 is rotatably supported, and the first support layer 11 may be wound around the supply reel 111.

As shown in FIG. 4, the drying portion 113 for drying the positive electrode mixture coated on one surface of the first support layer 11 by the coating portion 112, the coating portion 114 for applying the solid electrolyte layer forming material, and the coating portion 114. A drying portion 115 for drying the solid electrolyte layer forming material applied by the portion 114 may be provided. It is preferable that the first member M1 is formed by sequentially applying the treatments of the coating portion 112, the drying portion 113, the coating portion 114, and the drying portion 115 to the first support layer 11. The solid electrolyte layer forming material is, for example, a slurry containing a solid content (for example, a solid electrolyte or the like) and a solvent (for example, an organic solvent or the like).

As shown in FIG. 4, a drying portion 123 for drying the negative electrode mixture coated on one surface of the second support layer 12 by the coating portion 122, a coating portion 124 for applying the solid electrolyte layer forming material, and coating. A drying portion 125 for drying the solid electrolyte layer forming material applied by the portion 124 may be provided. It is preferable that the second member M2 is formed by sequentially applying the treatments of the coating portion 122, the drying portion 123, the coating portion 124, and the drying portion 125 to the second support layer 12. The second member M2 can be formed by a roll-to-roll method in the same manner as the first member M1 described above.

As shown in FIG. 4, a pair of press loins 61 and 62 may be provided in the transport path of the laminated body 1A. Further, the laminated body 1A may be conveyed while being guided by the guide roll, and may be continuously wound by the take-up reel 50.

<Second Embodiment>
As shown in FIGS. 2A (a) to 2 (e) and FIG. 2B (f), the method for producing the laminated body 1B according to the second embodiment of the present invention includes the following steps:
(4a) Step of preparing the first porous base material 10a and the second porous base material 10b;
(4b) A step of preparing a first member M1 including a first support layer 11 and a first solid electrolyte layer 13 provided on one surface side of the first support layer 11;
(4c) A step of preparing a second member M2 including a second support layer 12 and a second solid electrolyte layer 14 provided on one surface side of the second support layer 12;
(4d) A step of laminating the first porous base material 10a on the surface of the first member M1 on the side of the first solid electrolyte layer 13 to obtain the third member M3;
(4e) A step of laminating the second porous base material 10b on the surface of the second member M2 on the side of the second solid electrolyte layer 14 to obtain the fourth member M4;
(4f) The third member M3 and the fourth member M4 are placed on the surface of the third member M3 on the first porous base material 10a side and the surface of the fourth member M4 on the second porous base material 10b side. It includes a step of laminating so as to face each other to form a laminated body 1B.

The execution order of the steps 4a, 4b and 4c is not particularly limited. Step 4d is carried out after steps 4a and 4b, step 4e is carried out after steps 4a and 4c, and step 4f is carried out after steps 4d and 4e. Since the effect obtained by the second embodiment is the same as the effect of the first embodiment having steps 3a to 3d, the description here is omitted.

In the first embodiment having steps 3a to 3d, one porous base material 10 is used, whereas in the second embodiment having steps 4a to 4f, two porous base materials 10a and 10b are used. It differs in that it uses, but it can be the same in other respects. Specifically, the step 4a can be the same as the step 3a, the step 4b can be the same as the step 3b, the step 4c can be the same as the step 3c, and the steps 4d, 4e and 4f can be the same as the step 3d. Therefore, detailed description of steps 4a to 4f will be omitted.

The laminate 1B is preferably manufactured by a roll-to-roll method. By the roll-to-roll method, the laminated body 1B can be continuously manufactured, and the productivity of the laminated body 1B can be improved. Since the roll-to-roll method of the laminated body 1B can be manufactured in the same manner as the laminated body 1A, detailed description here will be omitted.

≪Manufacturing method of solid-state battery sheet≫
Hereinafter, embodiments of the method for manufacturing a solid-state battery sheet according to the present invention will be described with reference to FIGS. 1, 2 and 5. 1 (a) to 1 (e) are schematic process diagrams showing steps 1a to 1e in the method for manufacturing a solid battery sheet according to the first embodiment of the present invention, and FIGS. 2B (f) to 2 (g) are schematic process diagrams showing steps 2a to 2g in the method for manufacturing a solid battery sheet according to the second embodiment of the present invention, and FIG. 5A shows steps 1e and 2g. It is a top view of the solid-state battery sheet 5A and 5B formed, and FIG. 5B is a sectional view taken along the line AA of FIG. 5A. In each drawing, X indicates the length direction, Y indicates the width direction Y, and Z indicates the thickness direction. The length direction X, the width direction Y, and the thickness direction Z are orthogonal to each other. The length direction X corresponds to the machine direction (MD) at the time of manufacturing the solid-state battery sheets 5A and 5B.

As shown in FIGS. 1A to 1E, the method for manufacturing the solid-state battery sheet 5A according to the first embodiment of the present invention includes the following steps:
(1a) Step of preparing the porous base material 10;
(1b) A step of preparing a first member M1 including a first support layer 11 and a first solid electrolyte layer 13 provided on one surface side of the first support layer 11;
(1c) A step of preparing a second member M2 including a second support layer 12 and a second solid electrolyte layer 14 provided on one surface side of the second support layer 12;
(1d) A laminated body in which the first member M1 and the second member M2 are laminated via a porous base material 10 so that the first solid electrolyte layer 13 and the second solid electrolyte layer 14 face each other. The step of obtaining 1A; and (1e) including the step of pressing the laminate 1A in the thickness direction to form the sheet 5A for a solid-state battery.
As shown in FIGS. 5A and 5B, in the solid-state battery sheet 5A, at least a part of the first solid electrolyte layer 13 and at least a part of the second solid electrolyte layer 14 are the pores H of the porous base material 10. Is filled and in contact.

Since the effects obtained by the first embodiment of the present invention are the same as those described in the above-mentioned section of the method for producing a laminated body, the description thereof is omitted here.

<Step 1a to Step 1d>
Since steps 1a to 1d are the same as steps 3a to 3d in the above-described method for manufacturing a laminate, the description here is omitted.

<Step 1e>
Step 1e is a step of pressing the laminated body 1A in the thickness direction Z to form the solid-state battery sheet 5A.

In step 1e, by pressing the laminate 1A in the thickness direction Z, at least a part of the first solid electrolyte layer 13 is filled in the pores H from one surface of the porous base material 10, and the pores H are filled. At least a part of the second solid electrolyte layer 14 is filled in the pores H from the other surface of the porous base material 10, and the first solid electrolyte layer 13 and the second solid electrolyte layer 14 are the porous base material 10. Contact within. Here, "the first solid electrolyte layer 13 and the second solid electrolyte layer 14 come into contact with each other in the porous base material 10" means that the first solid electrolyte layer 13 passes through the pores H of the porous base material 10. It suffices if the solid electrolyte 14 and the second solid electrolyte 14 are in contact with each other, but when the solid battery sheet 5 obtained in step 1e is used for the solid battery, the first solid electrolyte is sufficiently driven so that the solid battery can be driven satisfactorily. It is preferable that the layer 13 and the second solid electrolyte layer 14 are in contact with each other.

A part of the first solid electrolyte layer 13 is filled in the pores H from one surface of the porous base material 10, and a part of the second solid electrolyte layer 14 is the other of the porous base material 10. By filling the pores H from the surface, it is possible to prevent non-uniform filling of the solid electrolyte with respect to the porous base material 10 and through holes of the solid electrolyte filled with the porous base material 10 resulting from this. .. Thereby, the battery performance can be improved.

The rest of the first solid electrolyte layer 13 (the portion of the first solid electrolyte layer 13 that was not filled in the pores H of the porous substrate 10) and the rest of the second solid electrolyte layer 14 (the second solid). The portion of the electrolyte layer 14 that was not filled in the pores H of the porous base material 10) remains on one and the other surface of the porous base material 10 while maintaining the form of the layer, respectively. Thereby, the exposure of the porous base material 10 can be prevented. Thereby, the contact property between the first solid electrolyte layer 13 and the positive electrode layer 15 and the contact property between the second solid electrolyte layer 14 and the negative electrode layer 16 can be improved, and the battery performance can be improved. In the first embodiment, assuming that the thickness of the first solid electrolyte layer 13 in the first member M1 prepared in step 1b is 1, the first solid battery sheet 5A obtained in step 1e The thickness of the remaining portion of the solid electrolyte layer 13 may be, for example, 0.1 or more, 0.2 or more, 0.3 or more, or 0.5 or more. good. The thickness of the remaining portion of the second solid electrolyte layer 14 when the thickness of the second solid electrolyte layer 14 in the second member M2 prepared in step 1c is 1, is the thickness of the remaining portion of the first solid described above. Since it can be the same as the numerical range in the electrolyte layer 13, it is omitted. The thickness is the average value of the thicknesses of 10 arbitrarily selected points.

The pressing method in the step 1e may be any method as long as the laminated body 1A can be pressed in the thickness direction, and is not particularly limited, and examples thereof include a roll press. Further, the pressure at the time of pressing is such that at least a part of the first solid electrolyte layer 13 is filled in the pores H from one surface of the porous base material 10, and at least a part of the second solid electrolyte layer 14 is filled. The pressure is such that a part of the pore H is filled from the other surface of the porous base material 10 so that the first solid electrolyte layer 13 and the second solid electrolyte layer 14 come into contact with each other in the porous base material 10. Is preferable.

The pressing method in the step 1e may be a method of pressing while heating the laminated body 1A, if necessary. For example, HIP (Hot Isostatic Press), WiP (Warm Isostatic Press), hot roll press and the like can be mentioned. Since the step 1e is a step of pressing the laminated body 1A while heating, the first solid electrolyte layer 13 and the second solid electrolyte layer 14 and the porous base material 10 are more firmly adhered to each other, and a stable sheet is obtained. Can be formed. Further, the first solid electrolyte layer 13 and the second solid electrolyte layer 14 and the porous base material 10 are more firmly adhered to each other, whereby the solid battery sheet 5A to the first support layer 11 and the second support are supported. The layer 12 can be satisfactorily peeled off. The heating temperature is not particularly limited, but is preferably, for example, 30 ° C. or higher, particularly preferably 50 ° C. or higher, and particularly preferably 70 ° C. or higher. On the other hand, the heating temperature is preferably, for example, 200 ° C. or lower, particularly preferably 150 ° C. or lower, and particularly preferably 100 ° C. or lower.

The thickness of the porous base material 10 may be reduced by pressing the laminate 1 in the thickness direction Z. Therefore, the thickness of the porous base material 10 after pressing may be smaller than the thickness of the porous base material 10 before pressing.

<Step 1f>
The first embodiment of the present invention may include a step of peeling the first support layer 11 and the second support layer 12 from the solid-state battery sheet 5A, if necessary.

The first support layer 11 and the second support layer 12 can be peeled off, for example, by pressing the solid-state battery sheet 5A or by bending the solid-state battery sheet 5A.

The solid-state battery sheet 5A can be used for manufacturing a solid-state battery. When the solid-state battery sheet 5A is used for manufacturing a solid-state battery, the solid-state battery sheet 5A may be cut into a desired shape. It should be noted that such cutting may be performed at a stage prior to the solid-state battery sheet 5A (for example, a manufacturing stage of the laminated body 1A, a manufacturing stage of the solid-state battery sheet 5A, etc.).

The solid-state battery is preferably a lithium solid-state battery. The lithium solid-state battery may be a primary battery or a secondary battery, but is preferably a lithium secondary battery. The solid-state battery includes not only a solid-state battery containing no liquid substance or gel-like substance as an electrolyte, but also an embodiment containing, for example, 50% by mass or less, 30% by mass or less, 10% by mass or less of a liquid substance or gel-like substance as an electrolyte. do. Examples of the form of the solid-state battery include a laminated type, a cylindrical type, and a square type.

The solid-state battery includes a positive electrode layer, a negative electrode layer, and a solid electrolyte layer located between the positive electrode layer and the negative electrode layer. The solid-state battery sheet 5A provided with the positive electrode layer and the negative electrode layer can be used as the positive electrode layer, the negative electrode layer, and the solid electrolyte layer among the constituent elements of the solid-state battery. Further, when the first support layer 11 has a function as a positive electrode current collector and the second support layer 12 has a function as a negative electrode current collector, the solid-state battery sheet 5A itself is used as a solid-state battery. can do.

In the embodiment in which the positive electrode layer 15 and the negative electrode layer 16 are omitted, the solid-state battery sheet 5A can be used as the solid electrolyte layer among the components of the solid-state battery. The positive electrode layer of the solid-state battery can be formed on the surface S1 of the first solid electrolyte layer 13 of the solid-state battery sheet 5A, and the negative electrode layer of the solid-state battery is the second solid electrolyte layer 14 of the solid-state battery sheet 5A. It can be formed on the surface S2 of. In the embodiment in which the positive electrode layer 15 and the negative electrode layer 16 are omitted, the battery performance can be improved as in the embodiment in which the positive electrode layer 15 and the negative electrode layer 16 are provided.

<Roll-to-roll method>
The solid-state battery sheet 5A is preferably manufactured by a roll-to-roll method. By the roll-to-roll method, the solid-state battery sheet 5A can be continuously manufactured, and the productivity of the solid-state battery sheet 5A can be improved.

Hereinafter, an embodiment of manufacturing the solid-state battery sheet 5A by a roll-to-roll method will be described with reference to FIG. FIG. 6 is a schematic view of the device used in this embodiment.

As shown in FIG. 6, a pair of press loins 75 and 76 are provided in the transport path of the laminate 1A, and the laminate 1A is pressed by the press loins 75 and 76 to form a solid-state battery sheet 5A. Can be obtained. Further, if necessary, the first support layer 11 and the second support layer 12 may be peeled off from the solid-state battery sheet 5A. For example, the first support layer 11 and the second support layer 12 may be peeled off from the solid-state battery sheet 5A by transporting the solid-state battery sheet 5A while being guided by the guide rolls 81, 82, 83. .. The peeled first support layer 11 was continuously wound by the take-up reel 72, and the solid-state battery sheet 5A was continuously taken up by the take-up reel 73 and peeled off. The support layer 12 may be continuously wound by the take-up reel 74.

<Second Embodiment>
As shown in FIGS. 2A (a) to (e) and FIGS. 2B (f) to (g), the method for manufacturing the solid-state battery sheet 5B according to the second embodiment of the present invention includes the following steps:
(2a) Step of preparing the first porous base material 10a and the second porous base material 10b;
(2b) A step of preparing a first member M1 including a first support layer 11 and a first solid electrolyte layer 13 provided on one surface side of the first support layer 11;
(2c) A step of preparing a second member M2 including a second support layer 12 and a second solid electrolyte layer 14 provided on one surface side of the second support layer 12;
(2d) A step of laminating the first porous base material 10a on the surface of the first member M1 on the side of the first solid electrolyte layer 13 to obtain the third member M3;
(2e) A step of laminating the second porous base material 10b on the surface of the second member M2 on the side of the second solid electrolyte layer 14 to obtain the fourth member M4;
(2f) The third member M3 and the fourth member M4 are placed on the surface of the third member M3 on the first porous base material 10a side and the surface of the fourth member M4 on the second porous base material 10b side. A step of laminating the laminate 1B so as to face each other; and a step of pressing (2 g) the laminate 1b in the thickness direction to form a solid-state battery sheet 5B are included.
As shown in FIGS. 5A and 5B, in the solid-state battery sheet 5B, at least a part of the first solid electrolyte layer 13 and at least a part of the second solid electrolyte layer 14 are the first porous base material 10a and The pores H of the second porous substrate 10b are filled and in contact with each other.

Since the effects obtained by the second embodiment of the present invention are the same as those described in the above-mentioned section of the method for producing a laminated body, the description thereof is omitted here.

<Step 2a to Step 2f>
Since steps 2a to 2f are the same as steps 4a to 4f in the above-described method for manufacturing a laminated body, the description thereof is omitted here.

<Process 2g>
Since step 2g is the same as step 1e in the method for manufacturing a solid-state battery sheet described above, the description here is omitted.

The description of the other solid-state battery sheet, the solid-state battery, and the roll-to-roll method can be the same as the description in steps 1a to 1e described above, and thus the description thereof is omitted here.

Hereinafter, the present invention will be described in more detail with reference to Examples.

・ Step 1a
As a porous substrate, a polyolefin non-woven fabric (thickness: 30 μm, material: polyethylene and polypropylene, basis weight: 5 g / m ² ) was prepared.

・ Step 1b
The first support layer (SUS foil, thickness: 10 μm) and the first solid electrolyte layer provided on one surface side of the first support layer (composition: solid electrolyte / binder = 99/1 (mass ratio). ), Thickness: 35 μm).

・ Process 1c
The second member was prepared in the same manner as the first member.

・ Step 1d
The first member and the second member were laminated via a porous base material so that the first solid electrolyte layer and the second solid electrolyte layer faced each other to obtain a laminated body (thickness: 120 μm). ..

・ Process 1e
The obtained laminate was roll-pressed to obtain a solid-state battery sheet (thickness: 45 μm).

-Evaluation The cross-sectional view of the obtained solid-state battery sheet in the thickness direction was visually observed from the cross-sectional image obtained by SEM (scanning electron microscope). As a result, at least a part of the first solid electrolyte layer and at least a part of the second solid electrolyte layer were filled in the pores of the porous substrate and brought into contact with each other. Further, as a result of comparison with the conventional solid-state battery sheet, it was found that the solid-state battery sheet of the present invention can effectively suppress the generation of through holes generated in the solid electrolyte layer.

1A, 1B ... Laminated body 5A, 5B ... Solid-state battery sheet M1 ... First member M2 ... Second member M3 ... Third member M4 ... Fourth member 10, 10a, 10b ... Porous base material 11 ... First support layer 12 ... Second support layer 13 ... First solid electrolyte layer 14 ... Second solid electrolyte layer 15 ... Positive electrode layer 16 ... Negative electrode layer 111, 121 ... Supply reel 112, 122, 114, 124 ... Coating part 113, 123, 115, 125 ... Drying part

Claims (8)

A method for manufacturing a first solid-state battery sheet.
The method is the following step:
(1a) Step of preparing a porous substrate;
(1b) A step of preparing a first member including a first support layer and a first solid electrolyte layer provided on one surface side of the first support layer;
(1c) A step of preparing a second member including a second support layer and a second solid electrolyte layer provided on one surface side of the second support layer;
(1d) The first member and the second member are laminated via the porous base material so that the first solid electrolyte layer and the second solid electrolyte layer face each other. (1e) The step of pressing the first laminate in the thickness direction to form the first solid-state battery sheet.
In the first solid-state battery sheet, at least a part of the first solid electrolyte layer and at least a part of the second solid electrolyte layer are filled in the pores of the porous base material and come into contact with each other. Yes, the method. A method for manufacturing a second solid-state battery sheet.
The method is the following step:
(2a) Step of preparing the first porous base material and the second porous base material;
(2b) A step of preparing a first member including a first support layer and a first solid electrolyte layer provided on one surface side of the first support layer;
(2c) A step of preparing a second member including a second support layer and a second solid electrolyte layer provided on one surface side of the second support layer;
(2d) A step of laminating the first porous base material on the surface of the first member on the side of the first solid electrolyte layer to obtain a third member;
(2e) A step of laminating the second porous base material on the surface of the second member on the side of the second solid electrolyte layer to obtain a fourth member;
(2f) The third member and the fourth member are placed on the surface of the third member on the side of the first porous base material and the surface of the fourth member on the side of the second porous base material. A step of laminating so as to face the surfaces to obtain a second laminate; and (2 g) a step of pressing the second laminate in the thickness direction to form the second solid-state battery sheet. Including
In the second solid-state battery sheet, at least a part of the first solid electrolyte layer and at least a part of the second solid electrolyte layer are the first porous substrate and the second porous. The method described above, wherein the pores of the substrate are filled and in contact with each other. The method according to claim 1 or 2, wherein the first solid electrolyte layer and the second solid electrolyte layer each contain a sulfide solid electrolyte. The first laminate or the second laminate is between the first support layer and the first solid electrolyte layer, or between the second support layer and the second solid electrolyte layer. The method according to any one of claims 1 to 3, wherein an electrode layer is provided on at least one of the spaces. The method for producing the first laminate according to claim 1, wherein the following steps:
(3a) Step of preparing a porous substrate;
(3b) A step of preparing a first member including a first support layer and a first solid electrolyte layer provided on one surface side of the first support layer;
(3c) A step of preparing a second member including a second support layer and a second solid electrolyte layer provided on one surface side of the second support layer; and (3d) the first. And the second member are laminated via the porous substrate so that the first solid electrolyte layer and the second solid electrolyte layer face each other to obtain a first laminate. The method described above. The method for producing the second laminate according to claim 2, wherein the following steps:
(4a) Step of preparing the first porous base material and the second porous base material;
(4b) A step of preparing a first member including a first support layer and a first solid electrolyte layer provided on one surface side of the first support layer;
(4c) A step of preparing a second member including a second support layer and a second solid electrolyte layer provided on one surface side of the second support layer;
(4d) A step of laminating the first porous base material on the surface of the first member on the side of the first solid electrolyte layer to obtain a third member;
(4e) A step of laminating the second porous base material on the surface of the second member on the side of the second solid electrolyte layer to obtain a fourth member; and (4f) the third member and The fourth member is laminated so that the surface of the third member on the first porous substrate side and the surface of the fourth member on the second porous substrate side face each other. The method comprising the step of forming a second laminate. The method according to claim 5 or 6, wherein the first solid electrolyte layer and the second solid electrolyte layer each contain a sulfide solid electrolyte. The first laminate or the second laminate is between the first support layer and the first solid electrolyte layer, or between the second support layer and the second solid electrolyte layer. The method according to any one of claims 5 to 7, wherein an electrode layer is provided on at least one of the spaces.

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