JP2013196933A - Solid state battery manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solid state battery manufacturing method which makes it possible to manufacture a solid state battery including an electrode body whose defect of shape is restrained.SOLUTION: The solid state battery manufacturing method includes an electrode layer fabrication step in which a flat cathode layer and a flat anode layer are fabricated; a solid state electrolyte layer fabrication step in which a flat solid state electrolyte layer is fabricated; a laminate fabrication step in which a laminate composed of a plurality of electrode bodies, each including the flat cathode layer and the flat anode layer and the flat solid state electrolyte layer disposed in between which are laminated one on another, is fabricated; an encapsulation step in which the laminate is housed in an encapsulation member and hermetically sealed therein; and an isotropic pressurization step in which the encapsulated laminate is subjected to isotropic pressurization.

Description

  The present invention relates to a method for manufacturing a solid state battery.

  Lithium ion secondary batteries have a higher energy density than conventional secondary batteries and can be operated at a high voltage. For this reason, it is used as a secondary battery that can be easily reduced in size and weight in information equipment such as a mobile phone, and in recent years, there is an increasing demand for large motive power such as for electric vehicles and hybrid vehicles.

  A lithium ion secondary battery has a positive electrode layer and a negative electrode layer, and an electrolyte layer disposed between them. Examples of the electrolyte used for the electrolyte layer include non-aqueous liquid and solid substances. Are known. When a liquid electrolyte (hereinafter referred to as “electrolytic solution”) is used, the electrolytic solution easily penetrates into the positive electrode layer and the negative electrode layer. Therefore, an interface between the active material contained in the positive electrode layer or the negative electrode layer and the electrolytic solution is easily formed, and the performance is easily improved. However, since the widely used electrolyte is flammable, it is necessary to mount a system for ensuring safety. On the other hand, when a solid electrolyte that is flame retardant (hereinafter referred to as “solid electrolyte”) is used, the above system can be simplified. Therefore, it is referred to as a lithium ion secondary battery (hereinafter referred to as “solid battery” or “all solid battery”) in a form provided with a layer containing a solid electrolyte (hereinafter referred to as “solid electrolyte layer”). The positive electrode layer, the solid electrolyte layer, and the negative electrode layer may be collectively referred to as an “electrode body”).

  As a technique related to such a lithium ion secondary battery, for example, Patent Document 1 includes a step of firing two electrode layer precursors of a positive electrode and a negative electrode, and a step of firing a solid electrolyte layer precursor, One electrode layer precursor is a molded body having at least an electrode material powder having a surface of electrode active material particles having a thickness of 1 nm to 200 nm, a covering ratio of 30% by area or more, and a solid electrolyte powder. An all-solid battery manufacturing method is disclosed. In the paragraph 0034 of Patent Document 1, in order to obtain a desired thickness of the solid electrolyte, electrode and the like after firing, the same kind of green sheets may be laminated, and the density of the solid electrolyte after firing is determined. In order to further improve, it is described that the green sheet may be pressed by a roll press, uniaxial, isotropic pressing or the like. In addition, in the paragraph 0046 of the specification of Patent Document 1, a laminate formed by laminating a negative electrode layer precursor, a solid electrolyte precursor, and a positive electrode layer precursor one by one in this order is sandwiched between SUS plates, and a rubber sheet is used. An example in which an all-solid battery is manufactured through a process of wrapping, vacuum-packing, and pressurizing with a cold isostatic press is disclosed. In addition, in Patent Document 2, before inserting the electrode group in which the plastic sheet disposed between the sheet-like positive electrode, the sheet-like negative electrode, and these electrodes is wound into a flat shape into the can case, A method for manufacturing an electrode group of a prismatic battery that is subjected to high temperature compression molding is disclosed. Patent Document 2 also discloses a form in which high-temperature compression molding is molding by isotropic pressure.

JP 2011-86610 A Japanese Patent Laid-Open No. 10-302827

  As disclosed in Patent Document 1, a laminate formed by laminating one each in the order of a negative electrode layer precursor, a solid electrolyte precursor, and a positive electrode layer precursor is sandwiched between SUS plates and wrapped with a rubber sheet. When a vacuum packing process is performed and pressure is applied with a cold isostatic press, shape defects (distortion such as warpage, etc .; the same applies hereinafter) are likely to occur in the electrode body. When constraining pressure is applied to an electrode body in which a shape defect has occurred, it is difficult to apply a uniform pressure to the lamination surface (a plane in which the lamination direction of each layer constituting the electrode body is a normal direction). Therefore, it is difficult to improve the performance of a solid battery including an electrode body having a defective shape, and there is a problem that the manufacturing cost tends to increase if the electrode body having a defective shape is discarded in order to prevent a decrease in performance. . Moreover, in patent document 2, the electrode group wound by flat shape is assumed. Therefore, even if the technique disclosed in Patent Document 1 and the technique disclosed in Patent Document 2 are combined, a flat electrode layer (positive electrode layer / negative electrode layer) and a flat solid electrolyte layer are laminated. It has been difficult to reduce the defective shape of the electrode body.

  Then, this invention makes it a subject to provide the manufacturing method of a solid battery which can manufacture a solid battery provided with the electrode body by which the shape defect was suppressed.

  As a result of intensive studies, the inventors reduced the shape defect of the electrode body by producing a solid battery through a process of isostatic pressure pressurization after accommodating a plurality of electrode bodies in a sealing material. It was found that the flatness of the solid battery can be secured. The present invention has been completed based on this finding.

In order to solve the above problems, the present invention takes the following means. That is,
The present invention relates to an electrode layer preparation step for producing a flat positive electrode layer and a flat negative electrode layer, a solid electrolyte layer preparation step for producing a flat solid electrolyte layer, and a laminated flat positive electrode layer and flat negative electrode layer. And a laminate manufacturing step for producing a laminate comprising a plurality of electrode bodies each having a flat solid electrolyte layer disposed between them, and a sealing step for accommodating the laminate in a sealing material and sealing the laminate, And an isotropic pressure pressurizing step of isostatically pressurizing the sealed laminated body.

  Here, in the present invention, “isotropic pressure pressurization” includes cold isostatic pressurization (CIP) and warm isostatic pressurization (WIP). Since it is possible to reduce the shape defect of the positive electrode layer and the negative electrode layer by accommodating a laminated body including a plurality of laminated electrode bodies in a sealing material and sealing and then applying isotropic pressure, It becomes possible to manufacture a solid battery including an electrode body in which defects are suppressed.

  In the present invention, the isotropic pressure may be cold isotropic pressure. By setting it as this form, it becomes possible to manufacture a solid battery provided with the electrode body by which the shape defect was suppressed, reducing manufacturing cost.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of a solid battery which can manufacture a solid battery provided with the electrode body by which the shape defect was suppressed can be provided.

It is a figure explaining the manufacturing method of the solid battery of the present invention concerning a 1st embodiment. It is a figure explaining the isotropic pressure pressurization process concerning 1st Embodiment. It is a figure which shows the mode at the time of the conventional isotropic pressure pressurization process start. It is a figure which shows the mode after the end of the conventional isotropic pressure pressurization process. It is a figure explaining the manufacturing method of the solid battery of the present invention concerning a 2nd embodiment. It is a figure explaining the isotropic pressure pressurization process concerning 2nd Embodiment. It is a figure which shows a mode that the solid battery of the Example was seen from the front. It is a figure which shows a mode that the solid battery of the Example was seen from the side surface. It is a figure which shows a mode that the solid battery of the comparative example was seen from the front. It is a figure which shows a mode that the solid battery of the comparative example was seen from diagonally.

  The present invention will be described below with reference to the drawings. In the following drawings, some of the repeated symbols may be omitted. In addition, the form shown below is an illustration of this invention and this invention is not limited to the form shown below.

  FIG. 1 is a view for explaining a method of manufacturing a solid state battery according to the first embodiment (hereinafter referred to as “the manufacturing method of the first embodiment”). The manufacturing method of the first embodiment shown in FIG. 1 includes an electrode layer manufacturing step (S11), a solid electrolyte layer manufacturing step (S12), a laminate manufacturing step (S13), a sealing step (S14), It has a sealing process (S15) and an isotropic pressure pressurizing process (S16).

  The electrode layer manufacturing step (hereinafter sometimes referred to as “S11”) is a step of manufacturing a flat positive electrode layer and a flat negative electrode layer. The form of S11 is not particularly limited as long as a flat positive electrode layer and a flat negative electrode layer can be produced. In S11, the flat positive electrode layer disposed on one end side in the stacking direction of the laminate described later is applied, for example, with a slurry-like positive electrode composition containing a positive electrode active material and a solid electrolyte on one surface of the flat current collector. It can be manufactured through a process of drying. In addition, the flat negative electrode layer disposed on the other end side in the stacking direction of the laminate described later is applied, for example, by applying a slurry-like negative electrode composition containing at least a negative electrode active material on one surface of the flat current collector It can be manufactured through the process of. In addition, a positive electrode layer and a negative electrode that are disposed at a position where another electrode layer (positive electrode layer and / or negative electrode layer) is interposed between an end surface on one end side in the stacking direction and an end surface on the other end side of the laminate described later. For example, the layer is prepared by applying a slurry-like positive electrode composition to the surface of the current collector on which the negative electrode layer is not formed and drying, and then preparing the positive electrode layer on the surface of the current collector on which the positive electrode layer is not formed. A negative electrode layer can be prepared through a process of applying and drying a slurry-like negative electrode composition (preparing a positive electrode layer on one surface of a current collector and a negative electrode layer on the opposite surface).

  The solid electrolyte layer manufacturing step (hereinafter, sometimes referred to as “S12”) is a step of manufacturing a flat solid electrolyte layer. The form of S12 is not particularly limited as long as a flat solid electrolyte layer can be produced. S12 can be produced, for example, through a process of applying and drying a slurry-like solid electrolyte composition containing a solid electrolyte on the surface of the flat positive electrode layer and / or flat negative electrode layer produced in S11.

  The laminate manufacturing step (hereinafter, also referred to as “S13”) is a step of manufacturing a laminate including a plurality of stacked electrode bodies. In S13, for example, the negative electrode layer is formed on one surface of the current collector and the solid electrolyte layer is formed on the surface of the negative electrode layer, and the positive electrode layer is disposed on the lower surface of the current collector. After laminating one or more structures having a negative electrode layer formed thereon and a solid electrolyte layer formed on the upper surface of the negative electrode layer, the lower surface of the current collector is transferred to the upper surface of the structure disposed on the uppermost surface. By laminating a positive electrode structure having a positive electrode layer formed thereon, a step of producing a laminate can be obtained.

  The sealing step (hereinafter, sometimes referred to as “S14”) is a step in which the laminate produced in S13 is accommodated in a laminate film and sealed while being decompressed. For example, S14 can be a step of sealing the laminate produced in S13 in a laminate film and then reducing the pressure in the laminate film to about 10 kPa using a vacuum packaging machine.

  The sealing step (hereinafter, sometimes referred to as “S15”) is a step in which the laminate sealed in S14 is accommodated in a water-resistant sealing material and sealed while reducing pressure. For example, S15 may be a step of sealing the laminate produced in S14 in a water-resistant film and then reducing the pressure in the water-resistant film to about 90 kPa using a degassing packaging machine.

  In the isotropic pressure pressurization step (hereinafter sometimes referred to as “S16”), the laminate sealed in the sealing material in S15 is placed in a container, and a fluid is filled between the sealing material and the container. After that, it is a step of applying isotropic pressure to the laminated body by applying a predetermined pressure. S16 is, for example, by putting the laminated body sealed in the sealing material in S15 into an iron container, putting water between the sealing material and the iron container, and then applying a pressure of 400 MPa at room temperature. And a step of cold isostatic pressing (CIP) of the laminate. FIG. 2 shows a configuration example of S16. As shown in FIG. 2, a water-resistant sealing material 3 and water 4 are accommodated in the container 5. A laminate film 2 is disposed in the sealing material 3, and the laminate 1 is disposed in the laminate film 2. In S <b> 16 shown in FIG. 2, the laminated body 1 sealed with the sealing material 3 and the laminate film 2 is put in the container 5, and water 4 is filled between the sealing material 3 and the container 5, The laminated body 1 is isotropically pressurized by closing the lid 5x and applying pressure through the lid 5x.

  3A and 3B are diagrams illustrating a state in which a single electrode body accommodated in a sealing material and a current collector (battery cell) connected thereto are pressurized with isotropic pressure. FIG. 3A is a diagram illustrating a state at the start of isotropic pressure pressurization, and FIG. 3B is a diagram illustrating a state after the end of isotropic pressure pressurization. A positive electrode active material and a negative electrode active material used in a solid state battery have different amounts of deformation with respect to pressure, and generally the negative electrode layer extends more than the positive electrode layer. Therefore, when an isotropic pressure is applied to a single electrode body and a current collector connected thereto, the negative electrode layer side having a large elongation rate is largely expanded, and the electrode body after the isotropic pressure application is distorted (warped). In addition, the adhesion between the positive electrode layer and the negative electrode layer and the solid electrolyte layer is lowered, and the performance of the solid battery is lowered. Since the difference in elongation between the positive electrode layer and the negative electrode layer increases as the area of the electrode increases, in the related art, the distortion (warpage) of the electrode increases as the area of the electrode of the solid battery increases.

  On the other hand, in the manufacturing method of the first embodiment in which the solid battery is manufactured through S11 to S16, isotropic pressure is applied after sealing the stacked electrode bodies in the sealing material. By applying isotropic pressure to multiple stacked electrode bodies, the negative electrode layer is restrained from being stretched compared to the case where a single electrode body is isotropically pressurized. Thus, the flatness of the solid battery can be ensured. Therefore, according to the manufacturing method of 1st Embodiment, it becomes possible to manufacture a solid battery provided with the electrode body by which the shape defect was suppressed. Further, by reducing the shape defect of the electrode body and ensuring the flatness of the solid battery, it becomes easy to improve the adhesion between the positive electrode layer and the negative electrode layer and the solid electrolyte layer, and thus the performance of the solid battery is easily improved. .

In the present invention, as the positive electrode active material contained in the positive electrode layer, a positive electrode active material that can be used in a solid battery can be appropriately used. As such a positive electrode active material, in addition to a layered active material such as lithium cobaltate (LiCoO ₂ ) and lithium nickelate (LiNiO ₂ ), an olivine type active material such as olivine type lithium iron phosphate (LiFePO ₄ ), A spinel type active material such as spinel type lithium manganate (LiMn ₂ O ₄ ) can be exemplified. The shape of the positive electrode active material can be, for example, particulate or thin film. The average particle size (D50) of the positive electrode active material is, for example, preferably from 1 nm to 100 μm, and more preferably from 10 nm to 30 μm. Further, the content of the positive electrode active material in the positive electrode layer is not particularly limited, but is preferably 40% or more and 99% or less in mass%, for example.

In the present invention, not only the solid electrolyte layer but also the positive electrode layer and the negative electrode layer can contain a known solid electrolyte that can be used in a solid battery, if necessary. Examples of such solid electrolytes include oxide-based amorphous solid electrolytes such as Li ₂ O—B ₂ O ₃ —P ₂ O ₅ and Li ₂ O—SiO ₂ , Li ₂ S—SiS ₂ , LiI—Li _{2. S-SiS 2, LiI-Li} 2 S-P 2 S 5, LiI-Li 2 S-P 2 O 5, LiI-Li 3 PO 4 -P 2 S 5, Li 2 S-P 2 S 5, Li 3 in addition to the sulfide-based amorphous solid electrolyte of PS _{4, etc., LiI, Li 3 N, Li} 5 La 3 Ta 2 O 12, Li 7 La 3 Zr 2 O 12, Li 6 BaLa 2 Ta 2 O 12, Li 3 Examples thereof include crystalline oxides and oxynitrides such as PO _{(4-3 / 2w)} N _w (w is w <1) and Li _3.6 Si _0.6 P _0.4 O ₄ . However, it is preferable to use a sulfide solid electrolyte as the solid electrolyte from the viewpoint of making a solid battery electrode that can easily improve the performance of the solid battery.

When a sulfide solid electrolyte is used as the solid electrolyte, the positive electrode active material is formed from the viewpoint of making it easy to prevent an increase in battery resistance by making it difficult to form a high resistance layer at the interface between the positive electrode active material and the solid electrolyte. It is preferable that it is coated with an ion conductive oxide. Examples of the lithium ion conductive oxide that coats the positive electrode active material include a general formula Li _x AO _y (A is B, C, Al, Si, P, S, Ti, Zr, Nb, Mo, Ta, or W). And x and y are positive numbers). Specifically, Li ₃ BO ₃ , LiBO ₂ , Li ₂ CO ₃ , LiAlO ₂ , Li ₄ SiO ₄ , Li ₂ SiO ₃ , Li ₃ PO ₄ , Li ₂ SO ₄ , Li ₂ TiO ₃ , Li ₄ Ti ₅ Examples include O ₁₂ , Li ₂ Ti ₂ O ₅ , Li ₂ ZrO ₃ , LiNbO ₃ , Li ₂ MoO ₄ , Li ₂ WO _{4 and the} like. The lithium ion conductive oxide may be a complex oxide. As the composite oxide covering the positive electrode active material, any combination of the above lithium ion conductive oxides can be employed. For example, Li ₄ SiO ₄ —Li ₃ BO ₃ , Li ₄ SiO ₄ —Li ₃ PO ₄ etc. can be mentioned. Further, when the surface of the positive electrode active material is coated with an ion conductive oxide, the ion conductive oxide only needs to cover at least a part of the positive electrode active material, and covers the entire surface of the positive electrode active material. Also good. In addition, the thickness of the ion conductive oxide covering the positive electrode active material is, for example, preferably from 0.1 nm to 100 nm, and more preferably from 1 nm to 20 nm. The thickness of the ion conductive oxide can be measured using, for example, a transmission electron microscope (TEM).

  Moreover, a positive electrode layer can be produced using the well-known binder which can be contained in the positive electrode layer of a lithium ion secondary battery. Examples of such a binder include acrylonitrile butadiene rubber (ABR), butadiene rubber (BR), polyvinylidene fluoride (PVdF), styrene butadiene rubber (SBR), and the like.

  Furthermore, the positive electrode layer may contain a conductive material that improves conductivity. Examples of the conductive material that can be contained in the positive electrode layer include carbon materials such as vapor grown carbon fiber, acetylene black (AB), ketjen black (KB), carbon nanotube (CNT), and carbon nanofiber (CNF). In addition, a metal material that can withstand the environment when the solid battery is used can be exemplified. When producing a positive electrode layer using a slurry-like positive electrode composition prepared by dispersing the positive electrode active material, solid electrolyte, and binder in a liquid, heptane and the like can be exemplified as a usable liquid. A nonpolar solvent can be preferably used. Further, the thickness of the positive electrode layer is, for example, preferably from 0.1 μm to 1 mm, and more preferably from 1 μm to 100 μm. In order to easily improve the performance of the solid state battery, the positive electrode layer is preferably produced through a pressing process. In the present invention, the pressure when pressing the positive electrode layer can be about 100 MPa.

Moreover, as a negative electrode active material contained in a negative electrode layer, the well-known negative electrode active material which can occlude / release lithium ion can be used suitably. Examples of such a negative electrode active material include a carbon active material, an oxide active material, and a metal active material. The carbon active material is not particularly limited as long as it contains carbon, and examples thereof include mesocarbon microbeads (MCMB), highly oriented graphite (HOPG), hard carbon, and soft carbon. Examples of the oxide active material include Nb ₂ O ₅ , Li ₄ Ti ₅ O ₁₂ , and SiO. Examples of the metal active material include In, Al, Si, and Sn. Further, a lithium-containing metal active material may be used as the negative electrode active material. The lithium-containing metal active material is not particularly limited as long as it is an active material containing at least Li, and may be Li metal or Li alloy. Examples of the Li alloy include an alloy containing Li and at least one of In, Al, Si, and Sn. The shape of the negative electrode active material can be, for example, particulate or thin film. The average particle diameter (D50) of the negative electrode active material is, for example, preferably from 1 nm to 100 μm, and more preferably from 10 nm to 30 μm. In addition, the content of the negative electrode active material in the negative electrode layer is not particularly limited, but is preferably 40% or more and 99% or less in mass%, for example.

  Further, the negative electrode layer may contain a binder for binding the negative electrode active material and the solid electrolyte, and a conductive material for improving conductivity. Examples of the binder and conductive material that can be contained in the negative electrode layer include the binder and conductive material that can be contained in the positive electrode layer. Further, when a negative electrode layer is prepared using a slurry-like negative electrode composition prepared by dispersing the negative electrode active material or the like in a liquid, heptane or the like can be exemplified as the liquid in which the negative electrode active material or the like is dispersed. A nonpolar solvent can be preferably used. Further, the thickness of the negative electrode layer is, for example, preferably from 0.1 μm to 1 mm, and more preferably from 1 μm to 100 μm. In order to easily improve the performance of the solid state battery, the negative electrode layer is preferably manufactured through a pressing process. In the present invention, the pressure when pressing the negative electrode layer is preferably 200 MPa or more, more preferably about 400 MPa.

  Moreover, as a solid electrolyte contained in the solid electrolyte layer, a known solid electrolyte that can be used in a solid battery can be appropriately used. Examples of such a solid electrolyte include the solid electrolyte that can be contained in the positive electrode layer and the negative electrode layer. In addition, the solid electrolyte layer can contain a binder that binds the solid electrolytes from the viewpoint of developing plasticity. As such a binder, the said binder etc. which can be contained in a positive electrode layer can be illustrated. However, in order to facilitate high output, it is included in the solid electrolyte layer from the viewpoint of preventing excessive aggregation of the solid electrolyte and enabling the formation of a solid electrolyte layer having a uniformly dispersed solid electrolyte. The binder is preferably 5% by mass or less. In addition, when producing a solid electrolyte layer through a process of applying a slurry-like solid electrolyte composition prepared by dispersing the solid electrolyte or the like in a liquid to the positive electrode layer or the negative electrode layer, the liquid for dispersing the solid electrolyte or the like Can be exemplified by heptane and the like, and a nonpolar solvent can be preferably used. The content of the solid electrolyte material in the solid electrolyte layer is mass%, for example, preferably 60% or more, more preferably 70% or more, and particularly preferably 80% or more. The thickness of the solid electrolyte layer varies greatly depending on the configuration of the battery. For example, the thickness is preferably 0.1 μm or more and 1 mm or less, and more preferably 1 μm or more and 100 μm or less.

  Moreover, the well-known metal which can be used as a collector of a solid battery can be used for the collector connected to a positive electrode layer or a negative electrode layer. As such a metal, a metal containing one or more elements selected from the group consisting of Cu, Ni, Al, V, Au, Pt, Mg, Fe, Ti, Co, Cr, Zn, Ge, and In. Materials can be exemplified.

  Moreover, as a laminated film which wraps an electrode body (laminated body in the manufacturing method of the said 1st Embodiment), the well-known laminated film which can be used with a solid battery can be used. Examples of such a laminate film include a resin laminate film, a film obtained by depositing a metal on a resin laminate film, and the like.

  Moreover, as a water-resistant sealing material used at a sealing process, the well-known sealing material which can prevent the penetration | invasion of a fluid at the time of isotropic pressure pressurization can be used suitably. Examples of such a sealing material include a resin-made laminate film having water resistance and pressure resistance, and a film obtained by vapor-depositing a metal on such a resin-made laminate film.

  FIG. 4 is a diagram for explaining a method for manufacturing a solid state battery according to the second embodiment (hereinafter referred to as “method for manufacturing the second embodiment”). The manufacturing method of the second embodiment shown in FIG. 4 includes an electrode layer manufacturing step (S21), a solid electrolyte layer manufacturing step (S22), a sealing step (S23), a laminate manufacturing step (S24), It has a sealing process (S25) and an isotropic pressure pressurizing process (S26).

  The electrode layer manufacturing step (hereinafter sometimes referred to as “S21”) is a step of manufacturing a flat positive electrode layer and a flat negative electrode layer. The form of S21 is not particularly limited as long as a flat positive electrode layer and a flat negative electrode layer can be produced. Since S21 is the same process as S11, description thereof is omitted here.

  The solid electrolyte layer manufacturing step (hereinafter, also referred to as “S22”) is a step of manufacturing a flat solid electrolyte layer. The form of S22 is not particularly limited as long as a flat solid electrolyte layer can be produced. Since S22 is the same process as S12, description thereof is omitted here.

  The sealing step (hereinafter sometimes referred to as “S23”) includes a flat positive electrode layer and a flat negative electrode layer connected to the current collector, and a flat solid electrolyte layer disposed therebetween. In this step, the electrode body is prepared, the electrode body is accommodated in a laminate film, and sealed under reduced pressure. For example, S23 can be a step of sealing the electrode body in the laminate film and then reducing the pressure in the laminate film to about 10 kPa using a vacuum packaging machine.

  In the laminate manufacturing step (hereinafter, sometimes referred to as “S24”), a laminate having a plurality of stacked electrode bodies, in which a plurality of laminate films prepared in S23 are sealed. It is a process of producing.

  The sealing step (hereinafter, sometimes referred to as “S25”) is a step in which the laminate produced in S24 is housed in a water-resistant sealing material and sealed while reducing pressure. For example, S25 can be a step of sealing the laminate produced in S24 in a water-resistant film and then reducing the pressure in the water-resistant film to about 90 kPa using a degassing packaging machine.

  In the isotropic pressure pressurization step (hereinafter sometimes referred to as “S26”), the laminate sealed in the sealing material in S25 is placed in a container, and a fluid is filled between the sealing material and the container. After that, it is a step of applying isotropic pressure to the laminated body by applying a predetermined pressure. S26 is, for example, by putting the laminate sealed in the sealing material in S25 into an iron container, putting water between the sealing material and the iron container, and then applying a pressure of 400 MPa at room temperature. And a step of cold isostatic pressing (CIP) of the laminate. FIG. 5 shows a configuration example of S26. As shown in FIG. 5, a water-resistant sealing material 3 and water 4 are accommodated in the container 5. A laminated body 6 is disposed in the sealing material 3, and the laminated body 6 has laminated laminate films 7, 7. In the laminate film 7, an electrode body 8 and a current collector connected to the electrode body 8 are arranged. In S26 shown in FIG. 5, after laminating films 7, 7,... And sealing material 3 in which the electrode body 8 and the like are sealed are put in the container 5 and water 4 is filled between the sealing material 3 and the container 5. Then, the lid 5x of the container 5 is closed, and pressure is applied through the lid 5x, whereby the laminate 6 is isotropically pressurized.

  Also in the manufacturing method of the second embodiment in which the solid battery is manufactured through S21 to S26, isotropic pressure is applied after sealing the plurality of stacked electrode bodies in the sealing material. By applying isotropic pressure to multiple stacked electrode bodies, the negative electrode layer is restrained from being stretched compared to the case where a single electrode body is isotropically pressurized. Thus, the flatness of the solid battery can be ensured. Therefore, it is possible to manufacture a solid battery including an electrode body in which shape defects are suppressed by the manufacturing method of the second embodiment. Further, by reducing the shape defect of the electrode body and ensuring the flatness of the solid battery, it becomes easy to improve the adhesion between the positive electrode layer and the negative electrode layer and the solid electrolyte layer, and thus the performance of the solid battery is easily improved. .

  In the said description regarding this invention, although the form whose solid battery is a lithium ion secondary battery was illustrated, this invention is not limited to the said form. The solid battery produced by the present invention may be in a form in which ions other than lithium ions move between the positive electrode layer and the negative electrode layer. Examples of such ions include sodium ions and potassium ions. In the case where ions other than lithium ions move, the positive electrode active material, the solid electrolyte, and the negative electrode active material may be appropriately selected according to the moving ions.

  A solid state battery was manufactured by the manufacturing method of the first embodiment and the conventional manufacturing method. The manufacturing method of the first embodiment was performed under the following conditions. That is, a flat positive electrode layer and a flat negative electrode layer are produced on the surface of the current collector, and further, a flat solid electrolyte layer is produced, and then these are laminated to form a laminate comprising two laminated electrode bodies. The body was made. Subsequently, after accommodating this in a laminate film, the pressure in the laminate film was reduced to about 10 kPa using a vacuum packaging machine and sealed. Subsequently, after the sealed laminate film was accommodated in the water resistant film, the pressure inside the water resistant film was reduced to about 90 kPa using a degassing packaging machine and sealed. Then, the water-resistant film and water were put into the container, and the laminated body was cold isostatically pressurized (CIP) by applying a pressure of 400 MPa at room temperature. The solid battery of the example produced in this way is shown in FIGS. FIG. 6 is a photograph showing the front of the solid battery of the example, and FIG. 7 is a photograph showing the side of the solid battery of the example.

  On the other hand, the solid battery of the comparative example was manufactured by the same process as the solid battery of the above example except that one electrode body and a current collector (single cell of the solid battery) connected to the electrode body were accommodated in the laminate film. Produced. A solid battery of a comparative example is shown in FIGS. FIG. 8 is a photograph showing the front of the solid battery of the comparative example, and FIG. 9 is a photograph showing the solid battery of the comparative example from an oblique direction.

  As shown in FIGS. 8 and 9, the solid battery of the comparative example was largely distorted, but as shown in FIGS. 6 and 7, the solid battery of the example was hardly distorted. As mentioned above, according to this invention, it was confirmed that a solid battery provided with the electrode body by which the shape defect was suppressed can be manufactured.

DESCRIPTION OF SYMBOLS 1, 6 ... Laminated body 2, 7 ... Laminate film 3 ... Sealing material 4 ... Water 5 ... Container 5x ... Lid 8 ... Electrode body

Claims (2)

An electrode layer production process for producing a flat positive electrode layer and a flat negative electrode layer;
A solid electrolyte layer production process for producing a flat solid electrolyte layer;
A laminated body producing step of producing a laminated body comprising a plurality of electrode bodies having the flat positive electrode layer and the flat negative electrode layer and the flat solid electrolyte layer disposed between the flat positive electrode layer and the flat positive electrode layer;
A sealing step of enclosing and sealing the laminate in a sealing material;
An isotropic pressure pressurizing step of applying isotropic pressure to the sealed laminate;
A method for producing a solid state battery. The method for producing a solid state battery according to claim 1, wherein the isotropic pressure is cold isotropic pressure.