Manufacturing method and manufacturing apparatus for solid-state battery

Abstract

To provide a method for manufacturing a solid-state battery that achieves both high density and improved productivity and favorable battery characteristics.SOLUTION: A method for manufacturing a solid battery having an electrode layer consisting of a positive electrode layer and a negative electrode layer, and a solid electrolyte layer including a first pressing step of pressing a layer including at least a solid electrolyte layer, an unevenness forming step of forming unevenness on the surface of the solid electrolyte layer, and a second pressing step of pressing the solid electrolyte layer and the electrode layer to form a laminate.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method and an apparatus for manufacturing a solid-state battery. [Background technology]

[0002] Conventionally, secondary batteries such as lithium-ion secondary batteries, which have high energy density, have been widely used. In recent years, there have been many developments, such as the improvement of energy efficiency, the reduction of adverse effects on the global environment by expanding the proportion of renewable energy, and the reduction of CO 2 From the viewpoint of reducing power consumption, the use of secondary batteries has been considered for various applications such as in-vehicle use. Secondary batteries have a structure in which a solid electrolyte (separator) is placed between a positive electrode and a negative electrode, and the battery is filled with a liquid or solid electrolyte (electrolytic solution).

[0003] Compared with secondary batteries using an electrolytic solution, solid-state batteries using a solid electrolyte have high thermal safety and can meet the demand for compactness. On the other hand, it is necessary to sufficiently improve the adhesion between the electrode layer and the solid electrolyte layer in a solid-state battery. For this reason, a technique is known in which the surfaces of the electrode layer and the solid electrolyte layer are provided with an uneven shape and then bonded together to improve the adhesion between the electrode layer and the solid electrolyte layer (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2017-103253 A Summary of the Invention [Problem to be solved by the invention]

[0005] In order to increase density and improve productivity, the electrode layer and the solid electrolyte layer in the solid secondary battery are preferably pressed in advance and then integrated and pressed. However, when the electrode layer and the solid electrolyte layer that have been pressed in advance are pressed together, the adhesion of the interface between the layers is not sufficient, and peeling may occur during the manufacturing process. Even if peeling does not occur, if the adhesion of the interface is insufficient, problems such as increased interface resistance, increased risk of Li precipitation, and decreased capacity rate characteristics occur, and there is a problem that favorable battery characteristics cannot be obtained. The technology disclosed in Patent Document 1 does not form an uneven shape on the surface of the electrode layer and the solid electrolyte layer after densification pressing, and there was a demand for a technology that can achieve both densification, improved productivity, and improved adhesion.

[0006] The present invention has been made in view of the above problems, and has an object to provide a method for manufacturing a solid-state battery that can achieve high density, improved productivity, and favorable battery characteristics at the same time. [Means for solving the problem]

[0007] (1) The present invention relates to a method for manufacturing a solid-state battery having an electrode layer consisting of a positive electrode layer and a negative electrode layer, and a solid electrolyte layer, the method including a first pressing step of pressing at least a layer including the solid electrolyte layer, a roughness forming step of forming roughness on a surface of the solid electrolyte layer, and a second pressing step of pressing the solid electrolyte layer and the electrode layer to form a laminate.

[0008] According to the invention of (1), it is possible to provide a method for producing a solid-state battery that can achieve both high density, improved productivity, and favorable battery characteristics.

[0009] (2) The present invention also relates to a method for producing a solid-state battery having an electrode layer consisting of a positive electrode layer and a negative electrode layer, and a solid electrolyte layer, the method comprising: a densification / irregularity-forming press step of pressing a layer including at least the solid electrolyte layer and forming irregularities on a surface of the solid electrolyte layer; and a second press step of pressing the solid electrolyte layer and the electrode layer to produce a laminate.

[0010] According to the invention of (2), since the formation of the irregularities for increasing density and improving adhesion can be performed in a single step, the manufacturing process for a solid-state battery that achieves both high density, improved productivity, and favorable battery characteristics can be simplified.

[0011] (3) The method for producing a solid-state battery according to (1) or (2), wherein the formation of the unevenness on the surface of the solid electrolyte layer is performed by a press machine having a protrusion at a contact portion that contacts the solid electrolyte layer, the protrusion at the contact portion forming an uneven shape on the surface of the solid electrolyte layer by the protrusion at the contact portion.

[0012] According to the invention of (3), continuous processing can be performed using a press device, so that the productivity of solid-state batteries can be further improved.

[0013] (4) The method for manufacturing a solid-state battery according to (3), wherein the contact portion in the press device is a sheet-like body having a convex portion formed on a surface thereof, and the sheet-like body is used by being wound around a cylindrical body.

[0014] According to the invention of (4), a press device having projections and recesses can be easily configured.

[0015] (5) The method for manufacturing a solid-state battery according to (4), wherein the sheet-like body is detachably provided on the cylindrical body.

[0016] According to the invention of (5), the uneven portion of the press device on which the unevenness is formed can be easily replaced, and the maintainability of the press device can be improved.

[0017] (6) The method for producing a solid-state battery according to (4) or (5), wherein the sheet-like body is sandpaper.

[0018] According to the invention of (6), a press device having projections and recesses can be easily and inexpensively constructed.

[0019] (7) The method for producing a solid-state battery according to any one of (4) to (6), wherein the cylindrical body is a zirconia tube.

[0020] According to the seventh aspect of the present invention, it is possible to preferably form projections and recesses on the surface of the solid electrolyte layer.

[0021] (8) The method for producing a solid-state battery according to (3), wherein the unevenness is formed on the surface of the solid electrolyte layer by continuously forming the unevenness using a roll having an uneven surface.

[0022] According to the invention (8), the productivity of solid-state batteries can be further improved.

[0023] (9) The method for producing a solid-state battery according to (3), wherein the unevenness is formed on the surface of the solid electrolyte layer continuously and in multiple steps by using a plurality of rolls having uneven surfaces.

[0024] According to the invention (9), the productivity of solid-state batteries can be further improved.

[0025] (10) The method for producing a solid-state battery according to (1) or (2), wherein the solid electrolyte layer has a first region having a predetermined thickness from a surface of the solid electrolyte layer inward, and a second region which is a region of the solid electrolyte layer further inward than the first region, and the formation of the irregularities on the surface of the solid electrolyte layer forms the irregularities only in the first region.

[0026] According to the invention of (10), the density of the solid electrolyte layer can be increased, and the adhesion between the solid electrolyte layer and the electrode layer can be improved.

[0027] (11) The present invention also relates to a solid-state battery manufacturing apparatus used for manufacturing a solid-state battery having an electrode layer consisting of a positive electrode layer and a negative electrode layer, and a solid electrolyte layer, the solid-state battery manufacturing apparatus including: a first pressing means for pressing a layer including at least the solid electrolyte layer; an irregularity forming means for forming irregularities on a surface of the solid electrolyte layer; and a second pressing means for pressing the solid electrolyte layer and the electrode layer to form a laminate.

[0028] According to the invention of (11), it is possible to provide a manufacturing apparatus for a solid-state battery that can achieve both high density, improved productivity, and favorable battery characteristics.

[0029] (12) The present invention also relates to a solid-state battery manufacturing apparatus used for manufacturing a solid-state battery having an electrode layer consisting of a positive electrode layer and a negative electrode layer, and a solid electrolyte layer, the solid-state battery manufacturing apparatus including: a densification / irregularity-forming press means for pressing a layer including at least the solid electrolyte layer and forming irregularities on a surface of the solid electrolyte layer; and a second press means for pressing the solid electrolyte layer and the electrode layer to form a laminate.

[0030] According to the invention of (12), since the formation of irregularities for increasing density and improving adhesion can be performed by a single means, it is possible to simplify the manufacturing apparatus for a solid-state battery that achieves both high density, improved productivity, and favorable battery characteristics.

[0031] (13) The apparatus for manufacturing a solid-state battery according to (11) or (12), wherein the means for forming the unevenness on the surface of the solid electrolyte layer is a means for continuously forming the unevenness by using a cylinder around which sandpaper is wound.

[0032] According to the invention of (13), the means for forming irregularities on the surface of the solid electrolyte layer can be constructed easily and inexpensively.

[0033] (14) The apparatus for manufacturing a solid-state battery according to (11) or (12), wherein the means for forming the unevenness on the surface of the solid electrolyte layer is a means for continuously forming the unevenness by using a metal roll having a sandblasted surface.

[0034] According to the invention (14), the productivity of solid-state batteries can be improved.

[0035] (15) The apparatus for manufacturing a solid-state battery according to (11) or (12), wherein the means for forming the unevenness on the surface of the solid electrolyte layer is a means for continuously forming the unevenness by rolls arranged in a plurality of stages and having unevenness on their surfaces.

[0036] According to the invention (15), the productivity of solid-state batteries can be further improved.

[0037] (16) The apparatus for manufacturing a solid-state battery according to (11) or (12), wherein a means for forming irregularities on the surface of the solid electrolyte layer forms convex portions on the surface of the solid electrolyte layer, and the second pressing means presses the solid electrolyte layer and the electrode layer together while crushing the convex portions to form a laminate.

[0038] According to the invention of (16), the adhesion between the solid electrolyte layer and the electrode layer can be improved. [Brief description of the drawings]

[0039] [Figure 1] 1 is a cross-sectional view showing a structure of a solid-state battery according to an embodiment of the present invention. [Diagram 2] FIG. 1 is a schematic diagram showing a solid-state battery manufacturing apparatus according to an embodiment of the present invention. [Diagram 3] FIG. 2 is a diagram showing a concave-convex forming means in a solid-state battery manufacturing apparatus. [Figure 4] 1 is a photomicrograph showing a cross section of a solid electrolyte layer according to a comparative example of the present invention. [Diagram 5] 1 is a photomicrograph showing a cross section of a solid electrolyte layer according to a comparative example of the present invention. [Figure 6] 1 is a micrograph showing a cross section of a solid electrolyte layer according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0040] First Embodiment Hereinafter, a method and an apparatus for manufacturing a solid-state battery according to a first embodiment of the present invention will be described. The method and apparatus for manufacturing a solid-state battery according to this embodiment is a method and an apparatus for manufacturing a solid-state battery 1 having an electrode layer composed of a positive electrode layer and a negative electrode layer, and a solid electrolyte layer.

[0041] (solid battery) As shown in FIG. 1, a solid-state battery 1 manufactured by the manufacturing method for a solid-state battery according to this embodiment is formed by stacking, in this order, a negative electrode layer 20 as an electrode layer, a solid electrolyte layer 40, and a positive electrode layer 30 as an electrode layer.

[0042] The negative electrode layer 20 is formed, for example, by forming a layer including a negative electrode active material 21 on a negative electrode current collector 22. The layer including the negative electrode active material 21 may include a solid electrolyte 5, a binder, a conductive assistant, and the like in addition to the negative electrode active material 21. The solid electrolyte 5, the binder, the conductive assistant, and the like are not particularly limited, and substances known as electrode materials for solid-state batteries can be applied.

[0043] The negative electrode active material 21 is not particularly limited, and any known material can be used as a negative electrode active material for solid-state batteries. As the negative electrode active material 21, for example, lithium titanate (Li 4 Ti 5 O 12 ) and other lithium transition metal oxides, TiO 2 , Nb 2 O 3 and WO 3 Examples of the metals include transition metal oxides such as those mentioned above, metal sulfides, metal nitrides, carbon materials such as graphite, soft carbon and hard carbon, metallic lithium, metallic indium and lithium alloys.

[0044] The negative electrode current collector 22 is not particularly limited, and may be any material known as a negative electrode current collector for solid secondary batteries. Examples of the negative electrode current collector 22 include copper and stainless steel. The copper, stainless steel, and the like are used in the form of, for example, a foil.

[0045] The solid electrolyte layer 40 is a layer that essentially contains a solid electrolyte 41. The solid electrolyte 41 is not particularly limited as long as it is a material capable of conducting lithium ions, and a substance known as a solid electrolyte used in a solid secondary battery can be applied. Examples of the solid electrolyte 41 include a sulfide-based solid electrolyte, an oxide-based solid electrolyte, a nitride-based solid electrolyte, and a halide-based solid electrolyte. The solid electrolyte layer 40 may contain a binder and the like in addition to the solid electrolyte 41.

[0046] The positive electrode layer 30 is formed, for example, by forming a layer including a positive electrode active material 31 on a positive electrode current collector 32. The layer including the positive electrode active material 31 may include a solid electrolyte 5, a binder, a conductive assistant, and the like in addition to the positive electrode active material 31. The solid electrolyte 5, the binder, the conductive assistant, and the like are not particularly limited, and substances known as electrode materials for solid-state batteries can be applied.

[0047] The positive electrode active material 31 is not particularly limited, and any material known as a positive electrode active material for solid-state batteries can be used. As the positive electrode active material 31, for example, LiCoO 2 , LiNiO 2 , LiCo 1 / 3 Ni 1 / 3 Mn 1 / 3 O 2 , LiVO 2 , LiCrO 2 Layered positive electrode active material particles such as LiMn 2 O 4 , Li(Ni 0.25 Mn 0.75 ) 2 O 4 , LiCoMnO 4 , Li 2 NiMn 3 O 8 Spinel-type positive electrode active materials such as LiCoPO 4 , LiMnPO 4 , LiFePO 4 For example, an olivine type positive electrode active material such as the above can be used.

[0048] The positive electrode current collector 32 is not particularly limited, and may be any material known as a positive electrode current collector for solid-state batteries. Examples of the positive electrode current collector 32 include aluminum and stainless steel. The aluminum and stainless steel are used in the form of foil. In addition to the above, a conductive carbon sheet (e.g., a graphite sheet or a CNT sheet) may be used.

[0049] <Solid-state battery manufacturing method> The method for manufacturing a solid-state battery according to this embodiment includes a first pressing step, a roughness forming step, and a second pressing step in which the solid electrolyte layer and the electrode layer are pressed to form a laminate. In addition to the above, the method for manufacturing a solid-state battery according to this embodiment includes an electrode layer forming step and a solid electrolyte layer forming method. Fig. 1 shows a state after the negative electrode layer 20 and the solid electrolyte layer 40 are integrated by the first pressing step and roughness is formed on the surface S of the solid electrolyte layer 40 by the roughness forming step described later, and shows a state before the integrated negative electrode layer 20 and solid electrolyte layer 40 and the positive electrode layer 30 are pressed by the second pressing step.

[0050] (Electrode layer formation process) A known method for forming electrodes for solid-state batteries can be applied to the electrode layer forming step for forming the anode layer 20 and the cathode layer 30 as electrode layers. For example, either a wet method or a dry method may be used. When the anode layer 20 and the cathode layer 30 are formed by a wet method, a method can be applied in which an electrode mixture slurry containing an electrode active material is applied to a current collector by a known method such as a doctor blade method and then dried.

[0051] (Solid electrolyte layer formation process) A known method for forming a solid electrolyte layer can be applied to the solid electrolyte layer forming step for forming the solid electrolyte layer 40. For example, the solid electrolyte may be pressed to form a sheet-like solid electrolyte, or the solid electrolyte may be formed through a process of applying a solid electrolyte paste prepared by dispersing the solid electrolyte in a solvent onto the surface of an electrode.

[0052] (First press process) The first pressing step is a step of pressing at least a layer including the solid electrolyte layer 40. The first pressing step presses at least a layer including the solid electrolyte layer 40 in advance (before the second pressing step) to densify it. The first pressing step preferably causes the solid electrolyte layer 40 to have a dynamic hardness of 20 or more, which will be described later. The first pressing step is, for example, a step of pressing the solid electrolyte layer 40 and one of the anode layer 20 and the cathode layer 30 to densify and integrate them. The first pressing step may be, for example, a step of pressing the solid electrolyte layer 40 formed by applying a solid electrolyte paste onto the anode layer 20 or the cathode layer 30 together with the anode layer 20 or the cathode layer 30, or a step of pressing the sheet-shaped solid electrolyte layer 40 together with the anode layer 20 or the cathode layer 30. Alternatively, it may be a step of pressing only the sheet-shaped solid electrolyte layer 40. It is preferable that the electrode layer that is not pressed by the first pressing step before the second pressing step is pressed separately before the second pressing step.

[0053] The specific method for performing the pressing in the first pressing step is not particularly limited, and examples thereof include uniaxial pressing, roll pressing, etc. Pressing conditions are, for example, 25° C., 6 to 10 ton / cm 2 It can be said that:

[0054] (Irregularity forming process) The unevenness forming step is a step of forming unevenness on the surface that is the lamination surface of the solid electrolyte layer 40. The solid electrolyte layer 40 is densified by the first pressing step, while the surface is smoothed, decreasing the interfacial adhesion. The unevenness forming step is a step of improving the decreased interfacial adhesion of the solid electrolyte layer 40.

[0055] When the solid electrolyte layer 40 and either the negative electrode layer or the positive electrode layer 30 are pressed and integrated together in the first pressing step, the unevenness forming step forms unevenness on one exposed lamination surface of the solid electrolyte layer 40. When only the sheet-like solid electrolyte layer 40 is pressed in the first pressing step, the unevenness forming step forms unevenness on both lamination surfaces of the sheet-like solid electrolyte layer 40.

[0056] The unevenness forming step forms unevenness only in a first region having a predetermined thickness from the surface of the solid electrolyte layer 40 inward. That is, the unevenness forming step causes a second region, which is a region where unevenness is not formed, to exist inside the solid electrolyte layer 40 in the thickness direction. This makes it possible to improve the adhesion between the solid electrolyte layer 40 and the electrode layer while maintaining the density of the solid electrolyte layer 40. Furthermore, the work process can be simplified and the manufacturing cost of the solid battery 1 can be reduced, compared to a method in which an electrolyte layer is newly formed on the surface of the solid electrolyte layer 40 by coating or the like after the first pressing step, for example.

[0057] The unevenness is formed in the first region by the unevenness forming step, and the dynamic hardness of the solid electrolyte layer 40 can be reduced. This can improve the adhesion when the solid electrolyte layer 40 and the electrode layer are integrated in the second pressing step. The dynamic hardness is an index used to evaluate the hardness of a thin film, and can be measured using a microhardness meter (for example, using a diamond triangular pyramid indenter as the indenter). It is preferable that the dynamic hardness of the solid electrolyte layer 40 becomes 10 or less in at least a part of the solid electrolyte layer 40 by the unevenness forming step.

[0058] The diameter of the projections and recesses formed in the projection and recess forming step is preferably 10 to 22 μm. The distribution of the projections and recesses formed in the projection and recess forming step is preferably 500 to 3000 points / mm. 2 It is preferable that:

[0059] The unevenness-forming step is preferably a step of continuously forming unevenness on the surface of the solid electrolyte layer 40 by using, for example, a roll having an uneven surface. This can improve the productivity of the solid state battery 1. A plurality of the rolls may be provided, and unevenness may be formed on the surface of the solid electrolyte layer 40 in multiple stages.

[0060] (Second press process) The second pressing step is a step of pressing and integrating the solid electrolyte layer 40 that has been through the first pressing step and the unevenness forming step with at least one of the electrode layers, the negative electrode layer 20 and the positive electrode layer 30, to produce a laminate. In the second pressing step, it is preferable to press the solid electrolyte layer 40 and the electrode layer while crushing the convex portions on the surface of the solid electrolyte layer 40 that has been through the unevenness forming step. This allows the solid electrolyte layer 40 with the unevenness formed thereon to be firmly pressed against the electrode layer.

[0061] The specific method for performing pressing in the second pressing step is not particularly limited, as in the first pressing step, and examples thereof include uniaxial pressing, roll pressing, etc. Pressing conditions are, for example, 25° C., 6 to 10 ton / cm 2 It can be said that:

[0062] <Solid-state battery manufacturing equipment> The solid-state battery manufacturing apparatus 10 according to the present embodiment described below is an example of a manufacturing apparatus capable of carrying out the above-described method for manufacturing a solid-state battery. As shown in FIG. 2, the solid-state battery manufacturing apparatus 10 includes a first pressing means 6, a concave-convex forming means 7, and a second pressing means 8.

[0063] (First Pressing Means) The first pressing means 6 is a means for performing the first pressing step, and is a means for pressing at least a layer including the solid electrolyte layer 40. In Fig. 2, the first pressing means 6 is a roll pressing device for stacking and pressing the sheet-like solid electrolyte layer 40 unwound from the winding body 4 and the negative electrode layer 20 unwound from the winding body 2. The first pressing means 6 is not limited to the above, and may be a uniaxial pressing device, a means for pressing a sheet-like body in which the solid electrolyte layer 40 is formed on the negative electrode layer 20 or the positive electrode layer 30, or a means for pressing only the sheet-like solid electrolyte layer 40.

[0064] (Irregularity forming means) The unevenness forming means 7 is a means for performing the unevenness forming step, and is a means for forming unevenness on the surface of the solid electrolyte layer 40 pressed by the first pressing means. The unevenness forming means 7 is provided at a stage subsequent to the first pressing means 6. In FIG. 2, the unevenness forming means 7 is a means for forming unevenness on one of the exposed lamination surfaces of the solid electrolyte layer 40. When the first pressing means 6 is a means for pressing only the sheet-like solid electrolyte layer 40, the unevenness forming means 7 may be a means for forming unevenness on both lamination surfaces of the solid electrolyte layer 40. In FIG. 2, the unevenness forming means 7 is composed of a single pressing device, but is not limited to the above, and the unevenness forming means 7 may be composed of a plurality of pressing devices provided in a plurality of stages.

[0065] The unevenness forming means 7 is, for example, a press device having a convex portion at a contact portion that contacts the solid electrolyte layer 40, and forming an uneven shape on the surface of the solid electrolyte layer 40 by the convex portion. The press device is configured, for example, as shown in FIG. 3, by winding a sheet-like body 71 having a convex portion formed on its surface around a cylindrical body 72. In addition to the above, the press device may be configured of a metal roll having a surface that is sandblasted to form unevenness. However, by detachably winding the sheet-like body 71 around the cylindrical body 72, replacement can be easily performed, and the maintainability of the solid-state battery manufacturing apparatus 10 can be improved.

[0066] The pressing device in the irregularity forming means 7 preferably uses sandpaper as the sheet-like body 71 having the protrusions formed on the surface thereof. Sandpaper is inexpensive and can be obtained with a preset grit size to form irregularities at a desired interval and size on the surface of the solid electrolyte layer 40. For example, it is preferable to use sandpaper with a grit size of 800 to 2000.

[0067] The pressing device in the unevenness forming means 7 is not particularly limited as long as it is a material having an optimum hardness for forming the cylindrical body 72 around which the sheet-like body 71 is wound, but it is preferable to use a ceramic or metal material. For example, zirconia (ZrO 2It is preferable to use a zirconia tube because the zirconia tube has the optimum hardness when wrapping sandpaper around the tube to form irregularities on the surface of the solid electrolyte layer 40. 2 ) has a flexural strength of 600 to 1400 MPa, a compressive strength of 3500 to 5600 MPa, and a Vickers hardness of 1250 to 1300 HV.

[0068] The second pressing means 8 is a means for carrying out the second pressing step. In FIG. 2, the second pressing means 8 is a roll pressing device that stacks and presses a laminate of the solid electrolyte layer 40 having the unevenness formed on its surface by the unevenness forming means 7, the negative electrode layer 20, and the positive electrode layer 30 unwound from the winding body 3. The second pressing means 8 is not limited to the above, and may be a uniaxial pressing device, or may be a device that stacks and presses the negative electrode layer 20 and the positive electrode layer 30 on the solid electrolyte layer 40 having the unevenness formed on both sides. The laminate produced by the second pressing means 8 is wound on the winding body 9.

[0069] Second Embodiment Hereinafter, a method and an apparatus for manufacturing a solid-state battery according to a second embodiment of the present invention will be described. Descriptions of configurations similar to those of the first embodiment will be omitted in some cases.

[0070] <Solid-state battery manufacturing method> The method for producing a solid-state battery according to this embodiment includes a densification / irregularity-forming press step and a second press step. The method for producing a solid-state battery according to this embodiment is the same as the method for producing a solid-state battery according to the first embodiment, except that the method includes the densification / irregularity-forming press step instead of the first press step and the irregularity-forming step.

[0071] (High density and uneven press process) The densification / irregularity-forming press step is a step of pressing at least a layer including the solid electrolyte layer and forming irregularities on the surface of the solid electrolyte layer. The densification / irregularity-forming press step is a step of performing the first pressing step and the irregularity-forming step according to the first embodiment in a single step.

[0072] The densification / irregularity-forming press step is, for example, a step of pressing the solid electrolyte layer 40 and one of the anode layer 20 and the cathode layer 30 to densify and integrate them, and forming irregularities on one exposed lamination surface of the solid electrolyte layer 40. Alternatively, it may be a step of pressing only the sheet-like solid electrolyte layer 40 to densify it, and forming irregularities on both lamination surfaces of the solid electrolyte layer 40.

[0073] The densification / irregularity-forming press step is preferably a step of continuously forming irregularities on the surface of the solid electrolyte layer 40 by, for example, a roll having an irregular surface. A plurality of rolls may be provided, and irregularities may be formed on the surface of the solid electrolyte layer 40 in multiple stages. A preferable configuration for forming irregularities on the surface of the solid electrolyte layer 40 by the densification / irregularity-forming press step may be the same as that of the above-mentioned irregularity-forming press step. The pressing pressure in the densification / irregularity-forming press step may be higher than that in the above-mentioned irregularity-forming press step.

[0074] <Solid-state battery manufacturing equipment> The solid-state battery manufacturing apparatus according to this embodiment includes a densification / irregularity-forming press means and a second press means. The solid-state battery manufacturing apparatus according to this embodiment is similar to the solid-state battery manufacturing apparatus according to the first embodiment, except that the densification / irregularity-forming press means is provided instead of the first press means and the irregularity-forming means.

[0075] (High density / uneven press method) The densification / irregularity-forming press means is a means for pressing at least a layer including the solid electrolyte layer and forming irregularities on the surface of the solid electrolyte layer. The densification / irregularity-forming press means is a means for performing the first pressing means and the irregularity-forming means according to the first embodiment in one step.

[0076] The densification / irregularity-forming press means is a means for performing the densification / irregularity-forming press step. As a preferable configuration for forming irregularities on the surface of the solid electrolyte layer 40 by the densification / irregularity-forming press means, a configuration similar to that of the irregularity-forming means can be applied.

[0077] The present invention is not limited to the above-described preferred embodiments, and various modifications can be made without departing from the spirit and scope of the present invention. EXAMPLES

[0078] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0079] [Laminate manufacturing] <Example 1> A positive electrode layer was prepared by applying a slurry containing a positive electrode active material onto a positive electrode current collector, and a solid electrolyte layer was prepared by applying a solid electrolyte slurry onto the positive electrode current collector. Each of the positive electrode layer and the solid electrolyte layer was then processed to a size of 10 mm in diameter. Next, the positive electrode layer and the solid electrolyte layer were each subjected to heating at 25°C and 6 ton / cm 2 (corresponding to the first pressing process). Next, a roller made by wrapping sandpaper (grit: 800) around a zirconia tube was rolled manually on the solid electrolyte layer (load: about 2 kg, 30 times) to form irregularities on the surface (corresponding to the irregularity forming process). The diameter of the irregularities formed was 21.8 μm, and the irregularity distribution was 592 Points / mm 2 Next, the surface of the solid electrolyte layer on which the projections and recesses were formed was overlapped with the positive electrode layer, and the resulting mixture was heated at 25° C. and 6 ton / cm 2 The laminate according to Example 1 was obtained by performing integration pressing (corresponding to the second pressing step) under the above conditions.

[0080] <Examples 2 and 3> The grit size of the sandpaper used to form the irregularities on the surface of the solid electrolyte layer was set to the grit size shown in Table 1 (Example 2: No. 1000, Example 3: No. 2000), and except that the irregularity diameter and irregularity distribution shown in Table 1 were formed, laminates according to Examples 2 and 3 were obtained in the same manner as in Example 1.

[0081] <Comparative Example 1> A laminate according to Comparative Example 1 was obtained in the same manner as in Example 1, except that the above-mentioned pre-pressing and the formation of irregularities on the surface of the solid electrolyte layer were not performed.

[0082] <Comparative Example 2> A laminate according to Comparative Example 2 was obtained in the same manner as in Example 1, except that no irregularities were formed on the surface of the solid electrolyte layer.

[0083] [Cross-section observation] The cross sections near the surface of the solid electrolyte layer before pressing to integrate it with the positive electrode layer in Example 1 and Comparative Examples 1 and 2 were observed by SEM (Miniscope (registered trademark) TM3000, manufactured by Hitachi High-Technologies Corporation). Fig. 4 is an SEM image of a cross section near the surface of the solid electrolyte layer in Comparative Example 1, Fig. 5 is an SEM image of a cross section near the surface where pre-pressing was performed in Comparative Example 2, and Fig. 6 is an SEM image of a cross section near the surface where unevenness was formed after pre-pressing in Example 1. The density of the solid electrolyte in Example 1 was 2.51 g / cm 3 and the density of the solid electrolyte of Comparative Example 1 was 1.72 g / cm 3 and the density of the solid electrolyte of Comparative Example 2 was 2.67 g / cm 3 The density of the solid electrolyte of Comparative Example 1, which was not subjected to pre-pressing, was lower than the densities of the solid electrolytes of Example 1 and Comparative Example 2.

[0084] 6, it was confirmed that the surface S of the solid electrolyte layer according to Example 1 had the same unevenness as that of Comparative Example 1 before the pre-pressing. In contrast, the surface of Comparative Example 2, which was only subjected to the pre-pressing, was flatter than that of Example 1 and Comparative Example 1.

[0085] [Tensile test] A sample for tensile testing (bonding area: 1×2 cm) was prepared based on the laminates according to the above examples and comparative examples. One side of the laminated surface of the sample was attached to a SUS plate with double-sided tape, and copper foil was attached to the other side. The SUS plate was fixed upright on a measurement stand (IMADA ZTA-2N, manufactured by IMADA Co., Ltd.). The copper foil was fixed to a force gauge (IMADA MX2-500N, manufactured by IMADA Co., Ltd.) and pulled at a speed of 100 mm / min in a direction perpendicular to the laminated surface of the laminate. The strength was measured when the sample broke or peeled off, and the condition after the test was observed. The results are shown in Table 1.

[0086] [Table 1]

[0087] "Base material destruction" in Table 1 indicates that destruction occurred at a location other than the interface between the positive electrode layer and the solid electrolyte layer during the tensile test, and "interface peeling" indicates that peeling occurred at the interface between the positive electrode layer and the solid electrolyte layer during the tensile test.

[0088] From the results in Table 1, it was confirmed that in the samples according to each Example, even though the pre-pressing was performed, no peeling occurred at the interface in the tensile test, and sufficient adhesion was ensured between the solid electrolyte layer and the electrode layer. In contrast, in Comparative Example 2, in which only the pre-pressing was performed, peeling occurred at the interface, the tensile strength was low, and sufficient adhesion was not obtained between the solid electrolyte layer and the electrode layer. [Explanation of symbols]

[0089] 1 solid state battery 10. Solid-state battery manufacturing equipment 20 Negative electrode layer (electrode layer) 30 Positive electrode layer (electrode layer) 40 Solid electrolyte layer 6 First Press Method 7. Means for forming unevenness (pressing device) 71 Sheet-like material (sandpaper) 72 Cylinder (zirconia tube) 8. Secondary Pressing Means

Claims

1. A method for manufacturing a solid-state battery having an electrode layer including a positive electrode layer and a negative electrode layer, and a solid electrolyte layer, comprising the steps of: a first pressing step of pressing at least a layer including the solid electrolyte layer; a step of forming irregularities on a surface of the solid electrolyte layer; a second pressing step of pressing the solid electrolyte layer and the electrode layer to form a laminate; A method for producing a solid-state battery, wherein the diameter of the projections and recesses formed in the projection-and-recess forming step is 10.3 to 21.8 μm, and the projections and recesses have a distribution of 592 to 2525 points / mm 2 .

2. A method for manufacturing a solid-state battery having an electrode layer including a positive electrode layer and a negative electrode layer, and a solid electrolyte layer, comprising the steps of: a densification / unevenness-forming press process for pressing at least a layer including the solid electrolyte layer and forming unevenness on a surface of the solid electrolyte layer; a second pressing step of pressing the solid electrolyte layer and the electrode layer to form a laminate.

3. The formation of the unevenness on the surface of the solid electrolyte layer is 3. The method for producing a solid-state battery according to claim 1, wherein the method is performed by using a pressing machine having a protrusion at a contact portion that contacts the solid electrolyte layer, the protrusion of the contact portion forming an uneven shape on the surface of the solid electrolyte layer.

4. the contact portion of the pressing device is a sheet-like body having a convex portion formed on a surface thereof, The method for manufacturing a solid-state battery according to claim 3 , wherein the sheet-like body is used by being wound around a cylindrical body.

5. The method for manufacturing a solid-state battery according to claim 4 , wherein the sheet-like body is detachably provided on the cylindrical body.

6. The method for manufacturing a solid-state battery according to claim 4 or 5, wherein the sheet-like body is sandpaper.

7. The method for manufacturing a solid-state battery according to any one of claims 4 to 6, wherein the cylindrical body is a zirconia tube.

8. The method for producing a solid-state battery according to claim 3 , wherein the unevenness is formed on the surface of the solid electrolyte layer by using a roll having an uneven surface to continuously form the unevenness.

9. 4. The method for producing a solid-state battery according to claim 3, wherein the unevenness is formed on the surface of the solid electrolyte layer continuously and in multiple steps by using a plurality of rolls having uneven surfaces.

10. the solid electrolyte layer has a first region having a predetermined thickness from a surface of the solid electrolyte layer to an inner side, and a second region which is a region of the solid electrolyte layer further inward than the first region, The method for producing a solid-state battery according to claim 1 , wherein the unevenness is formed on the surface of the solid electrolyte layer only in the first region.

11. A solid-state battery manufacturing apparatus used for manufacturing a solid-state battery having an electrode layer including a positive electrode layer and a negative electrode layer, and a solid electrolyte layer, comprising: a first pressing means for pressing at least a layer including the solid electrolyte layer; a projection-recess forming means for forming projections and recesses on the surface of the solid electrolyte layer; a second pressing means for pressing the solid electrolyte layer and the electrode layer to form a laminate; The diameter of the irregularities formed by the irregularity forming means is 10.3 to 21.8 μm, and the distribution of the irregularities is 592 to 2525 points / mm 2 .

12. A solid-state battery manufacturing apparatus used for manufacturing a solid-state battery having an electrode layer including a positive electrode layer and a negative electrode layer, and a solid electrolyte layer, comprising: a densification and roughness-forming press means for pressing a layer including at least the solid electrolyte layer and forming roughness on a surface of the solid electrolyte layer; a second pressing means for pressing the solid electrolyte layer and the electrode layer to form a laminate.

13. 13. The apparatus for manufacturing a solid-state battery according to claim 11, wherein the means for forming the unevenness on the surface of the solid electrolyte layer is a means for continuously forming the unevenness by using a cylinder around which sandpaper is wound.

14. 13. The apparatus for manufacturing a solid-state battery according to claim 11, wherein the means for forming the irregularities on the surface of the solid electrolyte layer is a means for continuously forming the irregularities by using a metal roll having a sandblasted surface.

15. 13. The apparatus for manufacturing a solid-state battery according to claim 11, wherein the means for forming the unevenness on the surface of the solid electrolyte layer is a means for continuously forming the unevenness by rolls arranged in a plurality of stages and having unevenness on their surfaces.

16. a projection is formed on the surface of the solid electrolyte layer by a means for forming projections and recesses on the surface of the solid electrolyte layer; 13. The apparatus for manufacturing a solid-state battery according to claim 11, wherein the second pressing means presses the solid electrolyte layer and the electrode layer together while crushing the protrusions to form a laminate.

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