JP5817885B2 - Solid secondary battery - Google Patents

Description

The present invention relates to a solid secondary batteries.

  Development of a secondary battery that can be repeatedly charged as a power source for a mobile phone or a mobile computer has been underway. Among these secondary batteries, those using organic electrolytes are known, but secondary batteries using organic electrolytes have many side reactions, and there is a risk of liquid leakage and ignition. There was a need for safety considerations.

  A secondary battery using a solid electrolyte (solid secondary battery) has been reported as an attempt to remove the electrolyte (for example, Patent Documents 1 and 2). For example, in the case of a lithium ion secondary battery using a solid electrolyte, the ions that move in the electrolyte by the battery reaction are only lithium ions, so there are almost no side reactions, no flammable organic solution is contained, Since a sealing structure is not required, it is possible to reduce the size and thickness.

JP 2006-277797 A JP 2004-179158 A

  However, in the method of compacting the solid electrolyte powder together with the electrode active material powder as in the solid secondary battery of Patent Document 1, the interface between the solid electrolyte powder and the electrode active material powder or the interface between the solid electrolyte powders is an interface. There was a problem that contact was insufficient and high battery output could not be obtained. In addition, there is a problem that the interface contact becomes unstable due to the volume change accompanying the charge / discharge cycle, and the cycle life is deteriorated.

  On the other hand, as in the solid secondary battery of Patent Document 2, there has been reported one in which a positive electrode thin film, a solid electrolyte thin film, and a negative electrode thin film are sequentially laminated using a vapor phase thin film deposition method such as sputtering. In such a method of laminating thin films, the interface contact between the electrode and the solid electrolyte is good, and the thickness of the active material layer and the solid electrolyte layer can be reduced, so that a high battery output and a good cycle are achieved. Lifetime characteristics can be obtained.

  However, in this method, since the film thickness of each layer is small, the total thickness of the active material layer per unit area is small, and a secondary battery having a large capacity cannot be provided.

The present invention was made in view of such circumstances, and an object thereof is to provide a large capacity solid state secondary batteries with high output.

In order to solve the above problem, the present invention fills the interior of each of the plurality of first vertical holes with a solid electrolyte layer having a plurality of first vertical holes and a plurality of second vertical holes on a first surface. A first active material, a second active material filling the interior of each of the plurality of second vertical holes, a first electrode connecting the plurality of first active materials, and a plurality of the second active materials. a second electrode connected, only including,
The plurality of first vertical holes are surrounded by a bottom surface and an inner wall surface where the solid electrolyte layer is exposed,
The plurality of second vertical holes may be surrounded by a bottom surface and an inner wall surface where the solid electrolyte layer is exposed .
Each of the plurality of first vertical holes and each of the plurality of second vertical holes may be alternately arranged.
Either one of the first active material and the second active material may function as an active material on the positive electrode side, and either one may function as an active material on the negative electrode side.
The solid secondary battery according to the first aspect of the present invention includes a first active material layer having a plurality of vertical holes formed on one surface, and bottom surfaces and inner wall surfaces of the plurality of vertical holes formed in the first active material layer. A solid electrolyte layer formed in contact with the solid electrolyte layer, and a second active material layer formed in contact with the solid electrolyte layer, wherein one of the first active material layer and the second active material layer is the The first active material functions as an active material on the positive electrode side of the solid secondary battery, and either one functions as an active material on the negative electrode side, and the first active material layer and the second active material layer are not in contact with each other. The solid electrolyte layer is provided between the layer and the second active material layer.

  According to this configuration, since the interface between the active material and the solid electrolyte is formed on the bottom surface and the inner wall surface of the vertical hole, a positive electrode thin film, a solid electrolyte thin film, and a negative electrode thin film are simply laminated on a flat surface as in Patent Document 2. Compared with the case where it goes, the battery capacity per unit area can be improved dramatically. In addition, since the solid electrolyte is formed in a thin film shape along the bottom surface and inner wall surface of the vertical hole, the interface contact between the active material and the solid electrolyte is good, and the thickness of the solid electrolyte layer can be reduced. Therefore, high battery output and good cycle life characteristics can be obtained.

  In the solid secondary battery according to the first aspect of the present invention, it is desirable that the second active material layer is filled so as to fill the interior of each of the plurality of vertical holes via the solid electrolyte layer.

  According to this configuration, since the second active material layer is formed in the entire interior of the vertical hole so as to fill the vertical hole, a high battery output can be obtained.

  The solid secondary battery according to the second aspect of the present invention is in contact with a solid electrolyte layer having a plurality of first vertical holes and a plurality of second vertical holes on one surface, and an inner surface of the plurality of first vertical holes. A first active material layer formed; and a second active material layer formed in contact with an inner surface of the plurality of second vertical holes, wherein the first active material layer and the second active material layer Any one of them functions as an active material on the positive electrode side of the solid secondary battery, and either one functions as an active material on the negative electrode side, and the plurality of first vertical holes and the plurality of second vertical holes Are arranged adjacent to each other.

  According to this configuration, since the interface between the active material and the solid electrolyte is formed on the bottom surface and the inner wall surface of the vertical hole, a positive electrode thin film, a solid electrolyte thin film, and a negative electrode thin film are simply laminated on a flat surface as in Patent Document 2. Compared with the case where it goes, the battery capacity per unit area can be improved dramatically. Further, since the thickness of the solid electrolyte in the part functioning as a battery is determined by the distance between adjacent active material layers, a high battery output and good cycle life characteristics can be obtained by shortening this distance.

  In the solid state secondary battery according to the second aspect of the present invention, the first active material layer is filled in the entire interior of each of the plurality of first vertical holes, and the second active material layer includes the plurality of first active material layers. It is desirable to fill the entire inside of each of the two vertical holes.

  According to this configuration, since the first active material layer and the second active material layer are formed in the entire inside of the vertical hole so as to fill the vertical hole, high battery output can be obtained.

  In the solid state secondary battery of the second aspect of the present invention, each of the plurality of first vertical holes in the first direction on the one surface and the second direction intersecting the first direction on the one surface It is desirable that each of the plurality of second vertical holes is alternately and periodically disposed.

  According to this configuration, many second active material monks (or first active material layers) can be arranged around one first active material layer (or second active material layer). Therefore, the battery capacity per unit area can be improved, and a high-power solid secondary battery can be provided.

  The manufacturing method of the solid secondary battery of the 1st form of this invention has a 1st active material layer and a 2nd active material layer, and either one of the said 1st active material layer and the said 2nd active material layer One is a method for producing a solid secondary battery that functions as an active material on the positive electrode side, and the other functions as an active material on the negative electrode side, and forms the first active material layer having a plurality of vertical holes on one surface. A first step, a second step of forming a solid electrolyte layer on the inner surface of each of the plurality of vertical holes and the one surface, and forming the second active material layer on the surface of the solid electrolyte layer A first step of applying a first liquid material for forming the first active material layer to a mold having a plurality of protrusions formed on the surface thereof. A first sub-process, a second sub-process that solidifies the first liquid material to form the first active material layer, and the first sub-process, A third sub-step of separating the active material layer and said mold, characterized in that it comprises a.

  According to this method, since the interface between the active material and the solid electrolyte is formed on the bottom surface and the inner wall surface of the vertical hole, a positive electrode thin film, a solid electrolyte thin film, and a negative electrode thin film are simply laminated on a flat surface as in Patent Document 2. Compared with the case where it goes, the battery capacity per unit area can be improved dramatically. Further, since the solid electrolyte is formed in a thin film shape along the bottom surface and inner wall surface of the vertical hole, the interface contact between the active material and the solid electrolyte is good, and the thickness of the solid electrolyte thin film can be reduced. Therefore, high battery output and good cycle life characteristics can be obtained.

  In the method for manufacturing a solid secondary battery according to the first aspect of the present invention, the mold is preferably formed using a LIGA (Lithographie Galvanoformung Abformung) method.

  According to this method, since a vertical hole having a high aspect ratio can be formed, the battery capacity per unit area can be dramatically improved. Further, since the vertical holes are formed using the mold, a solid secondary battery having the same performance can be manufactured with good reproducibility.

  In the method for manufacturing a solid secondary battery according to the first aspect of the present invention, when the second sub-step is performed by heat treatment, the mold is formed of a resin, and the mold is burned by the heat treatment. It is desirable that the second sub-process and the third sub-process are performed as one process.

  According to this method, the first liquid material can be solidified and the mold can be removed at the same time, so that the manufacturing process is simplified.

  In the method for manufacturing a solid secondary battery according to the first aspect of the present invention, in the second step, the solid electrolyte layer is preferably formed by a vapor deposition method or a sol-gel method.

  According to this method, the interface contact between the solid electrolyte layer and the first active material layer can be improved. In addition, since the solid electrolyte layer can be thinned to a submicron level, resistance due to ion conduction in the solid electrolyte layer can be greatly reduced, and high output can be achieved.

  In the method for manufacturing a solid secondary battery according to the first aspect of the present invention, the third step is to apply a second liquid material for forming the second active material layer on the surface of the solid electrolyte thin layer. It is desirable to include the 4th subprocess to apply.

  According to this method, since the second active material layer can be formed in the entire interior of the vertical hole so as to fill the vertical hole, a high battery output can be obtained.

  The manufacturing method of the solid secondary battery of the 2nd form of this invention has a 1st active material layer and a 2nd active material layer, and either one of the said 1st active material layer and the said 2nd active material layer One is a method for manufacturing a solid secondary battery that functions as an active material on the positive electrode side, and the other functions as an active material on the negative electrode side, and forms a solid electrolyte layer having a plurality of vertical holes formed on one surface. A first active material layer that separates each of the plurality of vertical holes into either a first vertical hole or a second vertical hole and is in contact with the inner surface of each of the plurality of first vertical holes; And a third step of forming a second active material layer so as to be in contact with the inner surface in each of the plurality of second vertical holes, wherein the first step comprises a surface Applying a first liquid material of the solid electrolyte layer to a mold having a plurality of protrusions formed thereon A second substep for solidifying the first liquid material to form the solid electrolyte layer, and a third substep for separating the solid electrolyte layer and the mold. The separation of each of the plurality of vertical holes in the step 2 is characterized in that the first vertical hole and the second vertical hole are adjacent to each other.

  According to this method, since the interface between the active material and the solid electrolyte is formed on the bottom surface and the inner wall surface of the vertical hole, a positive electrode thin film, a solid electrolyte thin film, and a negative electrode thin film are simply laminated on a flat surface as in Patent Document 2. Compared with the case where it goes, the battery capacity per unit area can be improved dramatically. Further, since the thickness of the solid electrolyte in the part functioning as a battery is determined by the distance between adjacent active material layers, a high battery output and good cycle life characteristics can be obtained by shortening this distance.

  In the method for manufacturing a solid secondary battery according to the second aspect of the present invention, the mold is preferably formed using a LIGA (Lithographie Galvanoformung Abformung) method.

  According to this method, since a vertical hole having a high aspect ratio can be formed, the battery capacity per unit area can be dramatically improved. Further, since the vertical holes are formed using the mold, a solid secondary battery having the same performance can be manufactured with good reproducibility.

  In the method for manufacturing a solid secondary battery according to the second aspect of the present invention, when the second sub-step is performed by heat treatment, the mold is formed of a resin, and the mold is burned by the heat treatment. It is desirable that the second sub-process and the third sub-process are performed as one process.

  According to this method, the first liquid material can be solidified and the mold can be removed at the same time, so that the manufacturing process is simplified.

  In the method for manufacturing a solid secondary battery according to the second aspect of the present invention, the second step includes a fourth sub-filling of the liquid material forming the first active material layer into the first vertical hole. Preferably, the third step includes a fifth sub-step of filling the second vertical hole with a liquid material forming the second active material layer.

  According to this method, since the first active material layer and the second active material layer can be formed in the entire interior of the vertical hole so as to fill the vertical hole, high battery output can be obtained.

  In the method for manufacturing a solid secondary battery according to the second aspect of the present invention, it is desirable to use an inkjet method in the fourth sub-step and the fifth sub-step.

  According to this method, even when the diameter of the vertical hole is about several tens of μm, the liquid material can be selectively and efficiently filled.

It is explanatory drawing of the manufacturing method of the solid secondary battery of 1st Embodiment. It is explanatory drawing of the manufacturing process following FIG. It is explanatory drawing of the manufacturing process following FIG. It is explanatory drawing of the manufacturing process following FIG. It is explanatory drawing of the manufacturing process following FIG. It is explanatory drawing of the manufacturing process following FIG. It is explanatory drawing of the manufacturing method of the solid secondary battery of 2nd Embodiment. It is explanatory drawing of the manufacturing process following FIG. It is explanatory drawing of the manufacturing process following FIG. It is explanatory drawing of the manufacturing process following FIG. It is explanatory drawing of the manufacturing process following FIG. It is explanatory drawing of the manufacturing process following FIG.

  Embodiments of the present invention will be described below with reference to the drawings. In the following description, an XYZ orthogonal coordinate system is set, and the positional relationship of each member will be described with reference to this XYZ orthogonal coordinate system. A predetermined direction in the horizontal plane is defined as the X-axis direction, a direction orthogonal to the X-axis direction in the horizontal plane is defined as the Y-axis direction, and a direction orthogonal to the X-axis direction and the Y-axis direction (that is, the vertical direction) is defined as the Z-axis direction.

  1-6 is explanatory drawing of the manufacturing method of the solid secondary battery of 1st Embodiment of this invention. In the present embodiment, first, as shown in FIG. 1, a mold A in which a plurality of columnar protrusions 11 are formed on the surface of a base material 10 is prepared. The mold A includes, for example, a plurality of columnar protrusions 11 perpendicular to the plate surface on a plate-like base material 10. The protrusions 11 are periodically arranged at regular intervals in the X direction and the Y direction. In the present embodiment, the height of the protrusion 11 is 1200 μm, the diameter of the protrusion 11 is 120 μm, and the distance between the protrusions 11 (the distance between the centers of the cylinders) is 180 μm.

  The mold A is formed using, for example, a LIGA (Lithographie Galvanoformung Abformung) method. The LIGA method is a method for producing a fine shape having a large aspect ratio by combining X-ray lithography, electroforming, and molding. Specifically, a resist having a thickness of 100 μm or more is irradiated with X-rays generated from a synchrotron radiation apparatus having good straightness, and a pattern is transferred through an X-ray mask to obtain a depth (higher than 100 μm). In this way, ultra-precision parts having an arbitrary shape in the lateral direction are manufactured. A UV-LIGA method is also known in which a resist pattern is formed with ultraviolet light instead of synchrotron radiation. Methods of forming are also known.

  When forming the mold A by the LIGA method, for example, a resist layer (polymethyl methacrylate (PMMA)) having a thickness of 1200 μm is formed on a metal substrate, irradiated with synchrotron radiation (X-rays), and then on the mask. The pattern of the X-ray absorber is transferred to the resist layer. In the X-ray exposed portion of the resist layer, the polymer chain is broken, the molecular weight is reduced, and the resist layer is dissolved in the developer. The unexposed part remains unchanged. As a result, a resist fine structure having the same shape as the pattern of the X-ray absorber is formed.

  Next, metal (for example, nickel) is deposited on the dissolved portion of the resist layer by plating to produce a metal structure (electroforming). Then, the unexposed portion of the resist layer is removed to produce a mold (mold) made of the metal structure. This mold is a plate-like body having a high aspect ratio vertical hole corresponding to the projection 11 of the mold A. Resin is cast into the mold to form a mold A.

  After forming the mold A, as shown in FIG. 2, a positive electrode active material sol is applied to the surface of the mold A on which the protrusions 11 are formed, and the sol is solidified to remove the mold A (sol-gel method). ). Thereby, a plate-like positive electrode active material layer (first active material layer) 12 made of the positive electrode active material is obtained.

  When a resin such as polymethyl methacrylate (PMMA) is used as the mold A, the mold A is burned out by a high-temperature heat treatment for solidifying the sol, so that a new mold for removing the mold A can be obtained. No process is required.

As the positive electrode active material, lithium cobaltate (LiCoO ₂ ), lithium nickelate (LiNiO ₂ ), lithium manganate (LiMn ₂ O ₄ ), lithium titanate (Li ₄ Ti ₅ O ₁₂ ), or the like can be used. For example, when lithium cobaltate is used as the positive electrode active material, a solution in which lithium hydroxide (or lithium acetate), cobalt acetate, and acetic acid are dissolved in isopropyl alcohol (or methanol, ethanol) is used as the sol raw material. Can do. When lithium nickelate is used as the positive electrode active material, a solution in which lithium hydroxide (or lithium acetate), nickel acetate, and acetic acid are dissolved in isopropyl alcohol (or methanol, ethanol) can be used as the sol raw material. . When lithium manganate is used as the positive electrode active material, a solution in which lithium hydroxide (or lithium acetate), manganese acetate, acetic acid, and citric acid are dissolved in isopropyl alcohol (or methanol, ethanol) is used as the sol raw material. be able to. When lithium titanate is used as the positive electrode active material, a solution in which lithium hydroxide (or lithium acetate), isopropyl titanate, and acetic acid are dissolved in isopropyl alcohol (or methanol or ethanol) is used as the sol raw material. it can.

  FIG. 3 is a cross-sectional view of the positive electrode active material layer 12 after the mold A is removed. The positive electrode active material layer 12 has a plurality of vertical holes 12H corresponding to the plurality of protrusions 11 of the mold A on the surface. The vertical holes 12H are periodically arranged at regular intervals in the X direction and the Y direction.

  When the positive electrode active material layer 12 is produced, as shown in FIG. 4, a solid electrolyte is disposed in contact with the surface of the positive electrode active material layer 12 where the vertical holes 12H are formed, and the upper surface 12a of the positive electrode active material layer 12 and the vertical holes 12H A thin-film solid electrolyte layer 13 covering the bottom surface 12b and the inner wall surface 12c is formed.

The solid electrolyte layer 13 may be formed by any method as long as a thin film having a uniform thickness can be formed on the bottom surface and inner wall surface of the high aspect ratio vertical hole 12H. For example, a vapor deposition method such as a CVD method or a sol-gel method can be used. When formed by the sol-gel method, Li _0.35 La _0.55 TiO ₃ can be used as the solid electrolyte. As a sol raw material, a solution in which lithium hydroxide (or lithium acetate), lanthanum acetate, isopropyl titanate, and acetic acid are dissolved in isopropyl alcohol (or methanol, ethanol) can be used.

  The solid electrolyte layer 13 is formed in a thin film shape with a thickness of, for example, 100 nm to 1 μm. Therefore, the vertical hole 12H is not buried by the solid electrolyte layer 13.

  After the solid electrolyte layer 13 is formed, a negative electrode active material layer (second active material layer) 14 is formed in contact with the exposed portion of the solid electrolyte layer 13 on the positive electrode active material layer 12 as shown in FIG. The negative electrode active material layer 14 is formed so as to cover the entire upper surface of the positive electrode active material layer 12 while covering the solid electrolyte layer 13 formed on the bottom surface and inner wall surface of the vertical hole 12H. The negative electrode active material layer 14 and the positive electrode active material layer 12 are not in contact with each other, and the solid electrolyte layer 13 is sandwiched between the negative electrode active material layer 14 and the positive electrode active material layer 12.

  The negative electrode active material layer 14 may be formed by any method as long as the negative electrode active material can be disposed on the bottom surface and inner wall surface of the high aspect ratio vertical hole 12H. For example, a vapor deposition method such as a CVD method, or a liquid process such as a sol-gel method or an inkjet method can be used. When a liquid process is used, it is desirable because a thick negative electrode active material layer can be formed so as to fill the inside of the vertical hole 12H.

  When the negative electrode active material layer 14 is formed by a liquid process, lithium or a metal having a low melting point (such as indium, tin, or wood metal) that dissolves lithium can be used as the negative electrode active material. Since these materials have a low melting point, they can be applied to the solid electrolyte layer 13 after being melted to form a liquid material.

As the negative electrode active material, lithium titanate (Li ₄ Ti ₅ O ₁₂ ) can also be used. In this case, it is formed by a sol-gel method. As the sol raw material, a solution in which lithium hydroxide (or lithium acetate), isopropyl titanate, and acetic acid are dissolved in isopropyl alcohol (or methanol, ethanol) is used. it can. Since this material has a low standard electrode potential, it can be used as a negative electrode.

  When the negative electrode active material layer 14 is formed by a liquid process, the negative electrode active material layer 14 is formed so as to fill the inside of the vertical hole 12H. Therefore, the negative electrode active material layer 14 has a columnar structure embedded in the vertical hole 12H via a solid electrolyte.

  When the negative electrode active material layer 14 is formed, as shown in FIG. 6, a positive electrode current collecting layer 15 and a positive electrode active material layer 12 are formed on the back surface of the positive electrode active material layer 12 (the surface opposite to the surface on which the vertical holes 12H are formed) as necessary. A positive electrode wiring layer (not shown) is formed, and a negative electrode current collecting layer 16 and a negative electrode wiring layer (not shown) are formed on the surface of the negative electrode active material layer 14 (the surface opposite to the surface in contact with the solid electrolyte layer 13). . Thereby, the solid secondary battery 1 is completed.

  According to the solid secondary battery 1 of the present embodiment, since the interface between the active material and the solid electrolyte is formed on the bottom surface 12b and the inner wall surface 12c of the vertical hole 12H, as in Patent Document 2, the positive electrode thin film is simply formed on the plane, The battery capacity per unit area can be dramatically improved as compared with the case where the solid electrolyte thin film and the negative electrode thin film are laminated. Further, since the solid electrolyte is formed in a thin film shape along the bottom surface and inner wall surface of the vertical hole, the interface contact between the active material and the solid electrolyte is good, and the thickness of the solid electrolyte can be reduced. High battery output and good cycle life characteristics can be obtained.

  In the solid secondary battery 1 of the present embodiment, the planar shape of the vertical hole 12H viewed from the Z direction is circular, and the vertical holes 12H are periodically arranged in the X direction and the Y direction. Not limited to this, it can take various shapes. For example, the area of the inner wall surface of the vertical hole can be maximized by making the planar shape of the vertical hole 12H square and shortening the interval between adjacent vertical holes as much as possible. In this case, since the contact interface between the solid electrolyte and the active material becomes large, a large-capacity solid secondary battery can be provided. Alternatively, the planar shape of the vertical hole 12H may be a regular hexagon, and the vertical hole 12H having a hexagonal column shape may be packed closest to the surface of the positive electrode active material layer 12. In this case, the same effect can be obtained.

  Further, in the solid secondary battery 1 of the present embodiment, the positive electrode active material is used as the material of the active material layer 12, but the negative electrode active material can also be used as the material of the active material layer 12. In this case, a negative electrode active material sol is applied to the mold A, and the sol is solidified to form a negative electrode active material layer. Then, a thin-film solid electrolyte layer is formed covering the bottom surface and inner wall surface of the vertical hole formed in the negative electrode active material layer, and a portion exposed on the negative electrode active material layer of the solid electrolyte layer is covered with the positive electrode active material layer. Form. The positive electrode active material layer may be formed in a thin film shape, or may be filled in the entire inside of the vertical hole through the solid electrolyte layer so as to fill the inside of the vertical hole. Also with this configuration, since the contact interface between the solid electrolyte and the active material can be increased, a large capacity and high output solid secondary battery can be obtained.

  7-12 is explanatory drawing of the manufacturing method of the solid secondary battery of 2nd Embodiment of this invention. In the present embodiment, first, as shown in FIG. 7, a forming die B in which a plurality of columnar protrusions 21 are formed on the surface of the base material 20 is prepared. The molding die B includes, for example, a plurality of columnar protrusions 21 perpendicular to the plate surface on a plate-like base material 20. The protrusions 21 are periodically arranged at regular intervals in the X direction and the Y direction. In the present embodiment, the height of the protrusion 21 is 1200 μm, the diameter of the protrusion 21 is 60 μm, and the distance between the protrusions 21 (the distance between the centers of the cylinders) is 120 μm. The mold B is formed using, for example, the LIGA method.

Then, as shown in FIG. 8, a solid electrolyte sol is applied to the surface of the mold B on which the projections 21 are formed, and the sol is solidified to remove the mold B (sol-gel method). Thereby, a plate-like solid electrolyte layer 22 made of a solid electrolyte is obtained. As the solid electrolyte, the aforementioned Li _0.35 La _0.55 TiO ₃ or the like can be used.

  When a resin such as polymethyl methacrylate (PMMA) is used as the mold B, the mold B is burned out by a high-temperature heat treatment for solidifying the sol, so that a new mold for removing the mold B can be obtained. No process is required.

FIG. 9 is a cross-sectional view of the solid electrolyte layer 22 after the mold B is removed. The solid electrolyte layer 22 has a plurality of vertical holes 22H formed on the surface corresponding to the plurality of protrusions 21 of the mold B.
The vertical holes 22H are periodically arranged at regular intervals in the X direction and the Y direction.

  When the solid electrolyte layer 22 is produced, as shown in FIG. 10, a positive electrode active material is disposed in a part of the plurality of vertical holes 22H, and the positive electrode active material layer ( First active material layer) 23 is formed. In addition, as shown in FIG. 11, a negative electrode active material is disposed in a vertical hole 22H other than the vertical hole in which the negative electrode active material layer 23 is formed, and is in contact with the bottom surface and inner wall surface of the vertical hole 22H. Material layer) 24 is formed.

  The active material layers 23 and 24 may be formed by any method as long as the active material can be disposed on the bottom surface and the inner wall surface of the high aspect ratio vertical hole 22H. For example, a vapor deposition method such as a CVD method, or a liquid process such as a sol-gel method or an inkjet method can be used. When a liquid process is used, a thick active material layer can be formed so as to fill the inside of the vertical hole 22H, which is desirable. In particular, when the inkjet method is used, the position and amount of the liquid material to be discharged can be precisely controlled, so that the positive electrode active material and the negative electrode active material can be reliably applied.

When the active material layer 23 is formed by the sol-gel method, the above-described materials can be used as the positive electrode active material and the negative electrode active material. That is, as the positive electrode active material, lithium cobaltate (LiCoO ₂ ), lithium nickelate (LiNiO ₂ ), lithium manganate (LiMn ₂ O ₄ ), lithium titanate (Li ₄ Ti ₅ O ₁₂ ), or the like is used. In addition, lithium titanate (Li ₄ Ti ₅ O ₁₂ ) or the like can be used as the negative electrode active material.

  Either the positive electrode active material layer 23 or the negative electrode active material layer 24 may be formed first, or both may be formed simultaneously. The positive electrode active material layer 23 and the negative electrode active material layer 34 are alternately and periodically disposed in both the X direction and the Y direction.

  When the positive electrode active material layer 23 and the negative electrode active material layer 24 are formed, as shown in FIG. 12, the positive electrode current collecting layer 25 and the positive electrode wiring layer ( A negative current collecting layer 26 and a negative electrode wiring layer (not shown) are formed in a portion exposed from the vertical hole 22H of the negative electrode active material layer 14. Thereby, the solid secondary battery 2 is completed.

  According to the solid secondary battery 2 of the present embodiment, since the interface between the active material and the solid electrolyte is formed on the bottom surface and the inner wall surface of the vertical hole 22H, as in Patent Document 2, the positive electrode thin film and the solid electrolyte are simply formed on a flat surface. Compared with the case where a thin film and a negative electrode thin film are laminated, the battery capacity per unit area can be dramatically improved. Further, since the thickness of the solid electrolyte in the part functioning as a battery is determined by the distance between adjacent active material layers, a high battery output and good cycle life characteristics can be obtained by shortening this distance.

  In the solid secondary battery 2 of the present embodiment, the planar shape of the vertical hole 22H viewed from the Z direction is circular, and the vertical holes 22H are periodically arranged in the X direction and the Y direction. Not limited to this, it can take various shapes. For example, the area of the inner wall surface of the vertical hole can be maximized by making the planar shape of the vertical hole 22H square and shortening the interval between adjacent vertical holes as much as possible. In this case, since the contact interface between the solid electrolyte and the active material becomes large, a large-capacity solid secondary battery can be provided. Alternatively, the planar shape of the vertical hole 22H may be a regular hexagon, and the hexagonal columnar vertical hole 22H may be packed closest to the surface of the solid electrolyte layer 22. In this case, the same effect can be obtained.

DESCRIPTION OF SYMBOLS 1, 2 ... Solid secondary battery, 11 ... Protrusion, 12 ... Positive electrode active material layer (1st active material layer), 12H ... Vertical hole, 13 ... Solid electrolyte layer, 14 ... Negative electrode active material layer (2nd active material layer) , 21 ... projection, 22 ... solid electrolyte layer, 22H ... vertical hole, 23 ... positive electrode active material layer (first active material layer), 24 ... negative electrode active material layer (second active material layer), A, B ... mold

Claims (3)

A solid electrolyte layer having a plurality of first vertical holes and a plurality of second vertical holes on a first surface;
A first active material filling the interior of each of the plurality of first vertical holes;
A second active material filling the inside of each of the plurality of second vertical holes;
A first electrode connecting a plurality of the first active materials;
A second electrode connected a plurality of the second active material, only including,
The plurality of first vertical holes are surrounded by a bottom surface and an inner wall surface where the solid electrolyte layer is exposed,
The solid secondary battery, wherein the plurality of second vertical holes are surrounded by a bottom surface and an inner wall surface where the solid electrolyte layer is exposed .   2. The solid secondary battery according to claim 1, wherein each of the plurality of first vertical holes and each of the plurality of second vertical holes are alternately arranged.   3. The device according to claim 1, wherein one of the first active material and the second active material functions as an active material on the positive electrode side, and the other functions as an active material on the negative electrode side. Solid secondary battery.

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