JP2016213105A - Active material mold manufacturing method, electrode composite manufacturing method, and lithium battery manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: an active material mold manufacturing method by which an active material mold enabling the materialization of a high-output and high-capacity lithium battery into reality can be manufactured efficiently; an electrode composite manufacturing method by which an electrode composite enabling the materialization of the above lithium battery can be manufactured efficiently; and a lithium battery manufacturing method by which the above lithium battery can be manufactured efficiently.SOLUTION: An active material mold manufacturing method comprises the steps of: preparing a laminate board 8 arranged by laminating a sacrificing layer 7 having a first concave part 711 and a second concave part 721, an upper substrate 81 (first lid part), and a lower substrate 82 (second lid part); deforming the sacrificing layer 7 by evacuating an external space S where the laminate board 8 is placed to expand the first concave part 711 and the second concave part 721 respectively; putting an active material forming material in the first concave part 711; and decomposing and removing the sacrificing layer 7 by heating the sacrificing layer 7 and the active material forming material respectively, thereby obtaining an active material mold.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a method for producing an active material molded body, a method for producing an electrode composite, and a method for producing a lithium battery.

  Lithium batteries (including primary batteries and secondary batteries) are used as a power source for many electric devices including portable information devices. The lithium battery includes a positive electrode, a negative electrode, and an electrolyte layer that is disposed between these layers and mediates conduction of lithium ions.

  In recent years, all-solid-state lithium batteries that use a solid electrolyte as a material for forming an electrolyte layer have been proposed as lithium batteries that achieve both high energy density and safety (see, for example, Patent Documents 1 to 3).

  However, as the power consumption of each electric device increases, not only these all solid-state lithium batteries but also non-solid-state lithium batteries are required to have higher output and higher capacity.

JP 2006-277797 A JP 2004-179158 A Japanese Patent No. 4615339

  One of the objects of the present invention is to provide an active material molded body capable of efficiently producing an active material molded body capable of realizing a lithium battery having high output and high capacity, and an electrode composite capable of realizing the lithium battery. It is providing the manufacturing method of the electrode complex which can manufacture efficiently, and the manufacturing method of the lithium battery which can manufacture the said lithium battery efficiently.

Such an object is achieved by the present invention described below.
The manufacturing method of the active material molded body of the present invention includes a first surface and a second surface facing each other, a plurality of first recesses opened in the first surface, and an opening in the second surface. A sacrificial layer having a plurality of second recesses;
A first lid for closing the opening of the first recess;
A preparation step of preparing a second lid portion that closes the opening of the second recess;
Decompressing the sacrificial layer by deforming the sacrificial layer by decompressing the space in which the sacrificial layer is placed and expanding the volume of the first recess and the volume of the second recess, respectively;
A filling step of placing an active material forming material in the first recess;
A heating step of decomposing and removing the sacrificial layer by heating the sacrificial layer and the active material forming material, and obtaining an active material molded body;
It is characterized by including.

  Thereby, since an active material molded object can be manufactured, shaping | molding a forming material with a 1st recessed part, even if it is a fine and complicated shape active material molded object, it can manufacture efficiently. Accordingly, an active material molded body that can realize a lithium battery having high output and high capacity can be efficiently produced.

  In the method for producing an active material molded body of the present invention, the first recess and the second recess are displaced from each other when the first surface is viewed in plan while seeing through the second surface. Is preferred.

  As a result, when the first recess and the second recess each expand in volume in the thickness direction of the sacrificial layer, the expansion is hardly inhibited from each other. As a result, the first concave portion and the second concave portion after volume expansion are each elongated with a length close to the thickness of the resin layer, and the aspect ratios of the first concave portion and the second concave portion are increased. Therefore, finally, an active material molded body capable of realizing a lithium battery having high output and high capacity can be obtained.

  In the method for producing an active material molded body of the present invention, when the first surface is viewed in plan while seeing through the second surface, the first recess and the second recess are regularly arranged, respectively. It is preferable that

  As a result, the volume of the first recess per unit volume can be easily increased, and the volume of the second recess adjacent to the first recess can be easily increased at the same time. By using the layer, the contact area between the active material molded body and the solid electrolyte layer can be increased while increasing the filling rate of the active material molded body. Therefore, by using such a sacrificial layer, an active material molded body capable of realizing a lithium battery having high output and high capacity can be obtained.

  In the method for producing an active material molded body of the present invention, in the filling step, after the first lid portion is removed from the sacrificial layer, the active material forming material is placed in each of the first recesses. It is preferable that the active material forming materials placed in the two matching first recesses are connected to each other.

  Thereby, when used in a lithium battery, an active material molded body having a sufficiently wide contact area with the current collector and capable of enhancing the electron conductivity with the current collector is obtained.

In the method for producing an active material molded body of the present invention, the constituent material of the sacrificial layer preferably includes a resin material.
Thereby, a sacrificial layer having high decomposability and moderate flexibility can be obtained.

The method for manufacturing an electrode assembly of the present invention includes a first surface and a second surface facing each other, a first recess opening in the first surface, and a second surface opening in the second surface. A sacrificial layer having a recess,
A first lid for closing the opening of the first recess;
A preparation step of preparing a second lid portion that closes the opening of the second recess;
Decompressing the sacrificial layer by deforming the sacrificial layer by decompressing the space in which the sacrificial layer is placed and expanding the volume of the first recess and the volume of the second recess, respectively;
A filling step of placing an active material forming material in the first recess and an electrolyte forming material in the second recess;
Heating the sacrificial layer, the active material forming material, and the electrolyte forming material, respectively, to decompose and remove the sacrificial layer and obtain an active material molded body and a solid electrolyte layer;
It is characterized by including.

  As a result, an active material molded body can be manufactured while the active material forming material is molded by the first recess, and a solid electrolyte layer can be manufactured while the electrolyte forming material is molded by the second recess. For example, even an active material molded body or a solid electrolyte layer including a portion having a large aspect ratio can be efficiently produced. Therefore, an electrode assembly capable of realizing a lithium battery having high output and high capacity can be efficiently manufactured.

  In the method for manufacturing an electrode assembly of the present invention, when the first surface is viewed in plan while seeing through the second surface, the first concave portion and the second concave portion are displaced from each other. preferable.

  As a result, when the first recess and the second recess each expand in volume in the thickness direction of the sacrificial layer, the expansion is hardly inhibited from each other. As a result, the first concave portion and the second concave portion after volume expansion are each elongated with a length close to the thickness of the resin layer, and the aspect ratios of the first concave portion and the second concave portion are increased. Therefore, finally, an electrode composite capable of realizing a lithium battery having high output and high capacity can be obtained.

  In the method for manufacturing an electrode assembly according to the present invention, when the first surface is viewed in plan while seeing through the second surface, the first recess and the second recess are regularly arranged. It is preferable.

  As a result, the volume of the first recess per unit volume can be easily increased, and the volume of the second recess adjacent to the first recess can be easily increased at the same time. By using the layer, the contact area between the active material molded body and the solid electrolyte layer can be increased while increasing the filling rate of the active material molded body and the solid electrolyte layer. Therefore, by using such a sacrificial layer, an active material molded body capable of realizing a lithium battery having high output and high capacity can be obtained.

The method for producing an electrode composite according to the present invention includes the filling step,
After removing the first lid from the sacrificial layer, the active material forming material is placed in each of the first recesses, and the active material is formed in two adjacent first recesses. While connecting materials together,
After the second lid portion is removed from the sacrificial layer, the electrolyte forming material is put into each of the second recesses, and the electrolyte forming materials are put into two adjacent second recesses. It is preferable to connect.

  Thereby, when used in a lithium battery, an electrode composite having an active material molded body having a sufficiently large contact area with respect to the current collector and a solid electrolyte layer having a sufficiently large contact area with respect to the electrode The body is obtained.

In the electrode composite manufacturing method of the present invention, it is preferable that the constituent material of the sacrificial layer includes a resin material.
Thereby, a sacrificial layer having high decomposability and moderate flexibility can be obtained.

The method for producing a lithium battery of the present invention includes a step of providing an electrolyte layer in contact with the active material molded body produced by the method for producing an active material molded body of the present invention,
Providing a current collector in contact with the active material molded body;
Providing an electrode in contact with the electrolyte layer;
It is characterized by including.

  Thereby, a lithium battery having high output and high capacity can be manufactured efficiently.

The lithium battery manufacturing method of the present invention includes a step of providing a current collector on one surface of the electrode composite manufactured by the electrode composite manufacturing method of the present invention so as to be in contact with the active material molded body,
Providing an electrode composition on the other surface of the electrode composite;
It is characterized by including.

  Thereby, a lithium battery having high output and high capacity can be manufactured efficiently.

It is a longitudinal cross-sectional view of the lithium secondary battery manufactured by applying the manufacturing method of the electrode assembly which concerns on this invention, and the manufacturing method of a lithium battery. It is a figure for demonstrating the manufacturing method of the electrode complex in the 1st manufacturing method of the lithium secondary battery shown in FIG. It is a figure for demonstrating the manufacturing method of the electrode complex in the 1st manufacturing method of the lithium secondary battery shown in FIG. It is a figure for demonstrating the manufacturing method of the electrode complex in the 1st manufacturing method of the lithium secondary battery shown in FIG. It is a figure for demonstrating the manufacturing method of the electrode complex in the 1st manufacturing method of the lithium secondary battery shown in FIG. It is a figure for demonstrating the manufacturing method of the electrode complex in the 1st manufacturing method of the lithium secondary battery shown in FIG. It is a figure for demonstrating the manufacturing method of the electrode complex in the 1st manufacturing method of the lithium secondary battery shown in FIG. It is a figure for demonstrating the manufacturing method of the electrode complex in the 1st manufacturing method of the lithium secondary battery shown in FIG. It is a figure for demonstrating the manufacturing method of the electrode complex in the 1st manufacturing method of the lithium secondary battery shown in FIG. It is a figure for demonstrating the manufacturing method of the electrode complex in the 1st manufacturing method of the lithium secondary battery shown in FIG. It is a figure for demonstrating the 1st manufacturing method of the lithium secondary battery shown in FIG. It is a figure for demonstrating the 2nd manufacturing method of the lithium secondary battery shown in FIG. It is a figure for demonstrating the 2nd manufacturing method of the lithium secondary battery shown in FIG. It is a longitudinal cross-sectional view of the lithium secondary battery in 2nd Embodiment. It is a longitudinal cross-sectional view of the lithium secondary battery in 3rd Embodiment. It is a longitudinal cross-sectional view of the lithium secondary battery in 4th Embodiment. It is the top view which saw through the lower surface (2nd surface) side from the upper surface (1st surface) side of the sacrificial layer which concerns on the other structural example.

  Hereinafter, a method for producing an active material molded body, a method for producing an electrode composite, and a method for producing a lithium battery according to the present invention will be described with reference to the drawings.

  In the drawings used for the description, the dimensions, ratios, and the like of the respective components are appropriately changed for easy understanding of the drawings and for easy understanding of the drawings, but this is for convenience. For convenience of explanation, the upper side of the description is referred to as “upper” and the lower side “lower”.

(First embodiment)
In the present embodiment, an active material molded body manufacturing method, an electrode composite manufacturing method, and a lithium battery manufacturing method according to the present invention will be described. In addition, a description will be given of a lithium secondary battery manufactured by applying the method for manufacturing an active material molded body, the method for manufacturing an electrode composite, and the method for manufacturing a lithium battery according to the present invention.

  First, a description will be given of a lithium secondary battery 100 manufactured by applying an active material molded body manufacturing method, an electrode composite manufacturing method, and a lithium battery manufacturing method according to the present invention. FIG. 1 is a longitudinal sectional view of a lithium secondary battery 100.

  The lithium secondary battery 100 includes a stacked body 10 and an electrode 20 joined on the stacked body 10. The lithium secondary battery 100 is a so-called all solid-state lithium (ion) secondary battery.

  The laminated body 10 includes a current collector 1, an active material molded body 2, and a solid electrolyte layer 3. Hereinafter, the combined structure of the active material molded body 2 and the solid electrolyte layer 3 is referred to as an electrode composite 4. The electrode assembly 4 is located between the current collector 1 and the electrode 20 and is bonded to each other on a pair of opposing surfaces 4a and 4b. Therefore, the laminate 10 has a configuration in which the current collector 1 and the electrode assembly 4 are laminated.

  The current collector 1 is an electrode for taking out the current generated by the battery reaction, and is provided in contact with the active material molded body 2 on the one surface 4 a of the electrode composite 4.

  The current collector 1 functions as a positive electrode when the active material molded body 2 is composed of a positive electrode active material, and functions as a negative electrode when the active material molded body 2 is composed of a negative electrode active material.

  Moreover, as a forming material (component material) of the current collector 1, for example, copper (Cu), magnesium (Mg), titanium (Ti), iron (Fe), cobalt (Co), nickel (Ni), zinc ( One metal selected from the group consisting of Zn), aluminum (Al), germanium (Ge), indium (In), gold (Au), platinum (Pt), silver (Ag) and palladium (Pd) And alloys containing two or more metal elements selected from this group.

  The shape of the current collector 1 is not particularly limited, and examples thereof include a plate shape, a foil shape, and a net shape. Further, the joint surface of the current collector 1 with the electrode composite 4 may be smooth or uneven, but the contact area with the electrode composite 4 is maximized. Preferably it is formed.

  The active material molded body 2 is a porous molded body that includes particulate active material particles 21 containing an active material as a forming material, and each of the plurality of active material particles 21 is three-dimensionally connected. is there.

  The active material molded body 2 which is a porous molded body has a plurality of pores. The pores in the plurality of pores are voids of the active material molded body 2. Portions of the active material molded body 2 that communicate with each other in a mesh form form communication holes. When the solid electrolyte layer 3 enters the communication hole, a wide contact area can be secured between the active material molded body 2 and the solid electrolyte layer 3.

  Moreover, the laminated body 10 (electrode assembly 4) of this embodiment is formed by a space (concave portion) in which the forming material of the active material molded body 2 and the forming material of the solid electrolyte layer 3 are separated from each other, as will be described in detail later. Thereafter, each mold (sacrificial layer) defining this space has an active material molded body 2 and a solid electrolyte layer 3 formed by heating. For this reason, the active material molded body 2 and the solid electrolyte layer 3 are each molded with a desired molding pattern and high precision based on the shape of the mold, and the contact area between the two depends on the molding pattern of both. It is possible to ensure the maximum. For this reason, the impedance at the interface between the active material molded body 2 and the solid electrolyte layer 3 is reduced, and favorable charge transfer at the interface becomes possible.

  Here, in the present embodiment, a plurality of active material particles 21 are aggregated to form an active material aggregate 25. The active material molded body 2 is formed by arranging a plurality of such active material aggregates 25 in layers.

  As shown in FIG. 1, each of the active material aggregates 25 according to the present embodiment has a columnar shape having a major axis in the direction connecting the current collector 1 and the electrode 20. The active material molded body 2 includes a plurality of active material aggregates 25 that are arranged at a predetermined distance from each other.

  Further, between the active material aggregates 25, a solid electrolyte layer 3 (electrolyte aggregate 35) formed in a columnar shape, which will be described later, is interposed. Therefore, in the electrode assembly 4 according to this embodiment, a wider contact area can be ensured between the active material aggregate 25 and the electrolyte aggregate 35.

  In addition, the active material aggregate 25 having a long axis in the direction connecting the current collector 1 and the electrode 20 can further promote charge transfer in this direction. Thereby, the output of the lithium secondary battery 100 can be further increased.

  The active material particles 21 can be either a positive electrode or a negative electrode by appropriately selecting the type of active material forming material.

  When the current collector 1 is used as a positive electrode, for example, a known lithium oxide can be used as a material for forming the active material particles 21 as the positive electrode active material, and in particular, a lithium double oxide can be preferably used.

  In the present specification, the “lithium double oxide” refers to an oxide that always contains lithium and contains two or more kinds of metal ions as a whole and in which the presence of oxo acid ions is not recognized.

Examples of such lithium double oxides include LiCoO ₂ , LiNiO ₂ , LiMn ₂ O ₄ , Li ₂ Mn ₂ O ₃ , LiFePO ₄ , Li ₂ FeP ₂ O ₇ , LiMnPO ₄ , LiFeBO ₃ , Li ₃ V _{2. (PO 4) 3, Li 2} CuO 2, LiFeF 3, Li 2 FeSiO 4, Li 2 MnSiO 4 , and the like. In this specification, solid solutions in which some atoms in the crystal of these lithium double oxides are substituted with other transition metals, typical metals, alkali metals, alkali rare earths, lanthanoids, chalcogenides, halogens, etc. These solid solutions can be used as the positive electrode active material.

Further, when the current collector 1 is a negative electrode, the active material molded body 2 is made of, for example, a lithium composite oxide such as Li ₄ Ti ₅ O ₁₂ or Li ₂ Ti ₃ O ₇ as a negative electrode active material. Can be used.

  By including such a lithium oxide, the active material particles 21 transfer electrons between the plurality of active material particles 21, and transfer lithium ions between the active material particles 21 and the solid electrolyte layer 3. The function as the active material molded body 2 is exhibited well.

  The average particle diameter of the active material particles 21 is preferably 300 nm to 5 μm, more preferably 450 nm to 3 μm, and further preferably 500 nm to 1 μm. When an active material having such an average particle diameter is used, the porosity of the obtained active material molded body 2 can be set within a preferable range. As a result, the surface area in the pores of the active material molded body 2 can be increased, and the contact area between the active material molded body 2 and the solid electrolyte layer 3 can be easily expanded, and the lithium battery using the laminate 10 can be easily increased in capacity. Become.

  Here, the porosity is, for example, (1) the volume (apparent volume) of the active material molded body 2 including pores obtained from the outer dimensions of the active material molded body 2 and (2) the active material molded body 2. And (3) the density of the active material constituting the active material molded body 2 can be measured based on the following formula (I).

  The porosity is preferably 10% or more and 50% or less, and more preferably 30% or more and 50% or less. Since the active material molded body 2 has such a porosity, the surface area in the pores of the active material molded body 2 is increased, and the contact area between the active material molded body 2 and the solid electrolyte layer 3 is easily expanded. It becomes easy to increase the capacity of the lithium battery using the laminate 10.

  When the average particle diameter of the active material particles 21 is less than the lower limit, depending on the type of the forming material of the solid electrolyte layer 3, the formed active material molded body has a fine pore radius of several tens of nanometers. This makes it difficult to allow the material for forming the solid electrolyte layer 3 to enter the pores, and as a result, it may be difficult to form the solid electrolyte layer 3 in contact with the surface inside the pores.

  Moreover, when the average particle diameter of the active material particles 21 exceeds the upper limit, the specific surface area, which is the surface area per unit mass, of the formed active material molded body 2 is reduced, and the active material molded body 2 and the solid electrolyte layer 3 are reduced. There is a risk that the contact area with the surface becomes small. Therefore, there is a possibility that sufficient output cannot be obtained in the lithium secondary battery 100. Moreover, since the ion diffusion distance from the inside of the active material particle 21 to the solid electrolyte layer 3 becomes long, the lithium oxide near the center in the active material particle 21 may hardly contribute to the function of the battery.

  The average particle diameter of the active material particles 21 is, for example, after dispersing the active material particles 21 in n-octanol so as to have a concentration in the range of 0.1% by mass to 10% by mass, and then the light scattering particle size. It can measure by calculating | requiring a median diameter using a distribution measuring apparatus (the Nikkiso Co., Ltd. make, nano track UPA-EX250).

  Moreover, although mentioned later in detail, the porosity of the active material molded object 2 is controllable by using the pore making material comprised in a particulate organic substance in the process of forming the active material molded object 2. FIG.

  On the other hand, the active material aggregate 25 according to the present embodiment is formed by aggregating a plurality of active material particles 21 as described above.

  The average length of the major axis of the active material aggregate 25 is preferably 5 μm or more and 500 μm or less, and more preferably 10 μm or more and 300 μm or less. When the active material aggregate 25 having such a major axis length is used, the aspect ratio of the active material aggregate 25 (ratio of the length of the major axis to the length of the minor axis) can be easily increased. For this reason, using such an active material aggregate 25 makes it easier to increase the contact area between the active material molded body 2 and the solid electrolyte layer 3 while increasing the charge mobility in the long axis direction. As a result, it is possible to achieve both high capacity and high output of the lithium secondary battery 100.

  In addition, the average length of the long axis of the active material aggregate 25 is obtained by, for example, observing the active material aggregate 25 with an electron microscope or the like to obtain the maximum length in the observation image and averaging 10 or more measured values. Is required.

  The average aspect ratio of the active material aggregate 25 is preferably 1.5 or more and 100 or less, and more preferably 5 or more and 50 or less. When the active material aggregate 25 having such an average aspect ratio is used, the short axis can be sufficiently shortened while sufficiently securing the surface area of the active material aggregate 25. It becomes possible to arrange the aggregates 25 with high density. For this reason, by arranging the active material aggregates 25 having a large surface area at a high density, it is possible to achieve both high charge mobility in the major axis direction of the active material aggregates 25 and high packing of the active material per unit volume. In addition, the electrode assembly 4 capable of realizing the lithium secondary battery 100 having a high output and a high capacity can be obtained.

  The average aspect ratio of the active material aggregate 25 is, for example, the maximum length in the direction orthogonal to the long axis, with the diameter of the maximum length as the major axis in the observation image of the active material aggregate 25 by an electron microscope or the like. When the diameter is the short axis, the ratio of the length of the long axis to the length of the short axis is obtained, and it is obtained by averaging 10 or more measured values.

  The solid electrolyte layer 3 is provided in contact with the surface of the active material molded body 2 using a solid electrolyte as a forming material (constituent material).

  Further, in the solid electrolyte layer 3 according to the present embodiment, the electrolyte aggregate 35 is formed by aggregating the plurality of granular bodies 31 with each other. The solid electrolyte layer 3 is formed by arranging a plurality of such electrolyte aggregates 35 in layers.

  As shown in FIG. 1, each of the electrolyte aggregates 35 according to the present embodiment has a columnar shape having a major axis in the direction connecting the current collector 1 and the electrode 20. The solid electrolyte layer 3 includes a plurality of electrolyte aggregates 35 that are arranged at a predetermined distance from each other.

  Further, the active material aggregate 25 described above is interposed between the electrolyte aggregates 35. Therefore, in the electrode assembly 4 according to the present embodiment, a wider contact area can be secured between the electrolyte aggregate 35 and the active material aggregate 25, and the output of the lithium secondary battery 100 can be increased. Can do. Moreover, the filling rate of the solid electrolyte per unit volume can be increased, and the capacity of the lithium secondary battery 100 can be increased.

  In addition, the electrolyte aggregate 35 having a long axis in the direction connecting the current collector 1 and the electrode 20 can further promote charge transfer in this direction. Thereby, the output of the lithium secondary battery 100 can be further increased.

The solid _{electrolyte, SiO 2 -P 2 O 5 -Li} 2 O, SiO 2 -P 2 O 5 -LiCl, Li 2 O-LiCl-B 2 O 3, Li 3.4 V 0.6 Si 0.4 O ₄ , Li ₁₄ ZnGe ₄ O ₁₆ , Li _3.6 V _0.4 Ge _0.6 O ₄ , Li _1.3 Ti _1.7 Al _0.3 (PO ₄ ) ₃ , Li _2.88 PO _{3. 73} N _0.14 , LiNbO ₃ , Li _0.35 La _0.55 TiO ₃ , Li ₇ La ₃ Zr ₂ O ₁₂ , Li ₂ S—SiS ₂ , Li ₂ S—SiS ₂ —LiI, Li ₂ S—SiS _{2 -P 2 S 5, LiPON,} Li 3 N, LiI, LiI-CaI 2, LiI-CaO, LiAlCl 4, LiAlF 4, LiI-Al 2 O 3, LiF-Al 2 O 3, LiBr-Al 2 O 3 , _{i 2 O-TiO 2, La} 2 O 3 -Li 2 O-TiO 2, Li 3 NI 2, Li 3 N-LiI-LiOH, Li 3 N-LiCl, Li 6 NBr 3, LiSO 4, Li 4 SiO 4 _{, Li 3 PO 4 -Li 4 SiO} 4, Li 4 GeO 4 -Li 3 VO 4, Li 4 SiO 4 -Li 3 VO 4, Li 4 GeO 4 -Zn 2 GeO 2, Li 4 SiO 4 -LiMoO 4, LiSiO Examples include oxides such as _4- Li ₄ ZrO ₄ , sulfides, halides, and nitrides. The solid electrolyte may be crystalline or amorphous. Further, in the present specification, solid solutions in which some atoms of these compositions are substituted with other transition metals, typical metals, alkali metals, alkali rare earths, lanthanoids, chalcogenides, halogens, and the like may be used as solid electrolytes. it can.

  Further, as the solid electrolyte, a lithium double oxide represented by the following formula (II) is particularly preferably used.

Li _7-x La ₃ (Zr _2-x , M _x ) O ₁₂ (II)
[Wherein M represents at least one of Nb, Sc, Ti, V, Y, Hf, Ta, Al, Si, Ga, Ge, Sn, and Sb, and X is a real number of 0 or more and 2 or less Represents. ]

  Note that M in the above formula is preferably at least one of Nb (niobium) and Ta (tantalum). Thereby, the lithium ion conductivity of the obtained solid electrolyte can be further increased, and the mechanical strength of the solid electrolyte can be further increased.

  In addition, X in the above formula, that is, the substitution rate of the metal M is preferably 1 or more and 2 or less, and more preferably 1.4 or more and 2 or less. If the X is too small, depending on the type of the metal M or the like, the solid electrolyte may not be able to fully exhibit the above-described functions.

The lithium double oxide represented by the above formula may have a cubic or tetragonal crystal structure, but preferably has a cubic garnet crystal structure. Thereby, the further improvement of the ionic conductivity of a solid electrolyte is achieved.
More specifically, Li _6.8 La ₃ Zr _1.8 Nb _0.2 O ₁₂ is particularly preferably used.

The solid electrolyte that is a constituent material of the solid electrolyte layer 3 according to the present embodiment is generated by firing (heating) a solid electrolyte precursor (electrolyte forming material). At the time of firing, the generated solid electrolyte constitutes a granular body 31 composed of secondary particles formed by granulating the primary particles. Therefore, although the solid electrolyte layer 3 is provided in contact with the surface of the active material molded body 2 including the inside of the voids of the active material molded body 2, the solid electrolyte layer 3 is configured by an aggregate of the granular bodies 31. As with the active material molded body 2, it is made of a porous body.
The solid electrolyte layer 3 is not necessarily a porous body, and may be a dense body.

The ionic conductivity of the solid electrolyte layer 3 is preferably 5 × 10 ⁻⁵ S / cm or more, and more preferably 1 × 10 ⁻⁵ S / cm or more. Since the solid electrolyte layer 3 has such ionic conductivity, ions contained in the solid electrolyte layer 3 at a position away from the surface of the active material molded body 2 reach the surface of the active material molded body 2, and the active material It becomes possible to contribute to the battery reaction in the molded body 2. Therefore, the utilization factor of the active material in the active material molded body 2 is improved, and the capacity can be increased. At this time, if the ionic conductivity is less than the lower limit value, depending on the type of the solid electrolyte layer 3, only the active material in the vicinity of the surface layer on the surface facing the counter electrode in the active material molded body 2 contributes to the battery reaction. May decrease.

  The “ionic conductivity of the solid electrolyte layer 3” refers to the “bulk conductivity” that is the conductivity of the inorganic electrolyte itself that constitutes the solid electrolyte layer 3, and the crystal in the case where the inorganic electrolyte is crystalline. It refers to the “total ionic conductivity” which is the sum of the “grain boundary ionic conductivity” which is the conductivity between particles.

  Further, the ionic conductivity of the solid electrolyte layer 3 is determined by, for example, pressing a solid electrolyte powder into a tablet shape at 624 MPa for 8 hours at 700 ° C. in an air atmosphere, and then sputtering to form both surfaces of the press-formed body. In addition, a platinum electrode having a diameter of 0.5 cm and a thickness of 100 nm is formed as a specimen, and then measured by an AC impedance method. For example, an impedance analyzer (manufactured by Solartron, model number SI1260) is used as the measuring device.

  On the other hand, as described above, the electrolyte aggregate 35 according to the present embodiment is formed by aggregating a plurality of granular bodies 31.

  The average length of the major axis of the electrolyte aggregate 35 is preferably 5 μm or more and 500 μm or less, and more preferably 10 μm or more and 300 μm or less. When the electrolyte aggregate 35 having such a long axis length is used, the aspect ratio of the electrolyte aggregate 35 can be easily increased. For this reason, by using such an electrolyte aggregate 35, it becomes easier to increase the contact area between the solid electrolyte layer 3 and the active material molded body 2 while increasing the charge mobility in the long axis direction. As a result, it is possible to achieve both high capacity and high output of the lithium secondary battery 100.

  The average length of the major axis of the electrolyte aggregate 35 is obtained by, for example, observing the electrolyte aggregate 35 with an electron microscope or the like to obtain the maximum length in the observation image and averaging ten or more measured values. Desired.

  The average aspect ratio of the electrolyte aggregate 35 is preferably 1.5 or more and 100 or less, and more preferably 5 or more and 50 or less. When the electrolyte aggregate 35 having such an average aspect ratio is used, the short axis can be sufficiently shortened while sufficiently securing the surface area of the electrolyte aggregate 35. Therefore, the electrolyte aggregate 35 is formed in the short axis direction. It becomes possible to arrange in high density. For this reason, the high capacity | capacitance and high output of the lithium secondary battery 100 can be made compatible by arrange | positioning the electrolyte aggregate 35 with a large surface area with high density.

  The average aspect ratio of the electrolyte aggregate 35 is, for example, that the electrolyte aggregate 35 is observed with an electron microscope or the like, the diameter of the maximum length in the observation image is the long axis, and the maximum length in the direction perpendicular to the long axis is When the diameter is the short axis, the ratio of the length of the long axis to the length of the short axis is obtained, and it is obtained by averaging 10 or more measured values.

  In addition, the laminate 10 may contain an organic substance such as a binder that joins the active materials and a conductive aid for ensuring the conductivity of the active material molded body 2. When the active material molded body 2 is molded, the active material molded body 2 is molded without using a binder, a conductive auxiliary agent, or the like, and is substantially composed of only an inorganic substance. Specifically, in this embodiment, the mass reduction rate when the electrode assembly 4 (the active material molded body 2 and the solid electrolyte layer 3) is heated at 400 ° C. for 30 minutes is 5% by mass or less. . The mass reduction rate is more preferably 3% by mass or less, further preferably 1% by mass or less, and particularly preferably no mass reduction is observed or an error range. Since the electrode composite 4 has such a mass reduction rate, the electrode composite 4 is vaporized by being burned or oxidized under a predetermined heating condition or a substance such as a solvent or adsorbed water that evaporates under a predetermined heating condition. An organic matter will be contained only 5 mass% or less with respect to the whole structure.

  The mass reduction rate of the electrode assembly 4 is determined by heating the electrode assembly 4 under predetermined heating conditions by using a differential thermal-thermogravimetric simultaneous measurement device (TG-DTA), and heating the electrode assembly 4 under predetermined heating conditions. The mass of the electrode assembly 4 can be measured and calculated from the ratio of the mass before heating to the mass after heating.

In the laminate 10 of the present embodiment, the active material molded body 2 has communication holes in which a plurality of pores communicate with each other in a mesh shape, and the solid portion of the active material molded body 2 also forms a network structure. doing. For example, LiCoO ₂ that is a positive electrode active material is known to have anisotropy in the electronic conductivity of crystals. Therefore, when trying to form an active material molded body using LiCoO ₂ as a forming material, a structure in which pores are extended in a specific direction, such as forming pores by machining, Depending on the direction of the electron conductivity, it may be difficult to conduct electrons inside. However, if the pores are connected in a network shape like the active material molded body 2 and the solid portion of the active material molded body 2 has a network structure, the anisotropy of the electron conductivity or ion conductivity of the crystal Regardless, an electrochemically lubricious continuous surface can be formed. Therefore, good electronic conduction can be ensured regardless of the type of active material used.

  Moreover, in the laminated body 10 of this embodiment, since the electrode assembly 4 is the above structures, the addition amount of the binder and conductive support agent contained in the electrode composite 4 can be suppressed, The capacity density per unit volume of the laminate 10 is improved as compared with the case where a conductive additive is used.

  Further, in manufacturing the laminate 10 (electrode assembly 4) of the present embodiment, as described above, the forming material of the active material molded body 2 and the forming material of the solid electrolyte layer 3 are formed by recesses that can accommodate each of them. Then, the active material molded body 2 and the solid electrolyte layer 3 are manufactured by heating the forming material for each sacrificial layer that defines the recess. For this reason, each of the active material molded body 2 and the solid electrolyte layer 3 has a desired molding pattern and is molded with high accuracy, and the contact area between the two can be maximized depending on the molding pattern of both. it can. For this reason, the impedance at the interface between the active material molded body 2 and the solid electrolyte layer 3 is reduced, and favorable charge transfer at the interface becomes possible.

  Therefore, the lithium secondary battery 100 having the stacked body 10 has an improved capacity per unit volume and higher output than other lithium secondary batteries not having the stacked body 10. It has become.

  In the lithium secondary battery 100, the electrode 20 is bonded to the other surface 4 b of the electrode assembly 4. The electrode 20 is provided in contact with the solid electrolyte layer 3 without being in contact with the active material molded body 2. With such a configuration, in the lithium secondary battery 100, the electrode 20 and the current collector 1 can be prevented from being connected via the active material molded body 2, that is, a short circuit can be prevented. Therefore, the solid electrolyte layer 3 also functions as a short-circuit prevention layer that prevents the occurrence of a short circuit in the lithium secondary battery 100.

  The electrode 20 functions as a negative electrode when the active material molded body 2 is composed of a positive electrode active material, and functions as a positive electrode when the active material molded body 2 is composed of a negative electrode active material.

  As a forming material (constituent material) of the electrode 20, for example, lithium (Li) may be used when the electrode 20 is a negative electrode, and for example, aluminum (Al) may be used when the electrode 20 is a positive electrode.

  Although the thickness of the electrode 20 is not specifically limited, For example, it is preferable that they are 1 micrometer or more and 100 micrometers or less, and it is more preferable that they are 20 micrometers or more and 50 micrometers or less.

  Next, an embodiment of a method for manufacturing the lithium secondary battery 100 shown in FIG. 1 will be described in two parts.

  First, an embodiment of a first method for producing a lithium secondary battery of the present invention and a method for producing an active material molded body of the present invention contained therein will be described.

  2-11 is a figure for demonstrating the 1st manufacturing method of the lithium secondary battery shown in FIG. In FIG. 2 and FIG. 6B, dots are added to the concave portions of the sacrificial layer.

  The first manufacturing method of the lithium secondary battery 100 includes: [1] a first recess 711 that opens to the upper surface 71 (first surface) and a second recess 721 that opens to the lower surface 72 (second surface). The sacrificial layer 7, the upper substrate 81 (first lid) that is stacked on the sacrificial layer 7 so as to close the first recess 711, and the lower layer that is stacked on the sacrificial layer 7 so as to close the second recess 721 A step of preparing a multilayer substrate 8 including a substrate 82 (second lid), [2] a step of decompressing a space in which the multilayer substrate 8 is placed, and [3] active in the first recess 711. A step of adding a first liquid material 201 containing a material forming material, and [4] heating the sacrificial layer 7 and the first liquid material 201 to decompose and remove the sacrificial layer 7, and to form an active material 2 and [5] forming the solid electrolyte layer 3 so as to be in contact with the active material molded body 2 It has a degree, a step of providing a current collector 1 in contact with [6] active material molded body 2, and a step of providing an electrode 20 in contact with [7] the solid electrolyte layer 3.

Hereinafter, each process will be described sequentially.
[1] First, as shown in FIGS. 2 to 4, a plurality of first recesses 711 opened on the upper surface 71 (first surface) and a plurality of second recesses opened on the lower surface 72 (second surface). A sacrificial layer 7 having 721 is prepared. 2 is a plan view of the sacrificial layer 7 as viewed from the upper surface 71 side, and FIG. 3 is a perspective view of the sacrificial layer 7 shown in FIG. These are the sectional views on the AA line of FIG.

  The sacrificial layer 7 includes a sheet-like resin layer 70 having an upper surface 71 and a lower surface 72 that are in a front-back relationship. Among these, a plurality of first recesses 711 are opened on the upper surface 71, and a plurality of second recesses 721 are opened on the lower surface 72.

  Since the resin layer 70 is decomposed and removed in a process to be described later, a material having excellent decomposability is preferably used. In addition, the resin layer 70 is required to expand as the first concave portion 711 and the second concave portion 721 expand in volume in a process described later. For this reason, the constituent material of the resin layer 70 is required to have not only decomposability but also appropriate flexibility.

  Examples of the constituent material of the resin layer 70 include rubbers (elastomers) including natural rubber latex and synthetic rubber latex, polyethylene, polystyrene, polypropylene, polyester, (meth) acrylic resin, polycarbonate, polylactic acid, A cellulose etc. are mentioned. The constituent material of the resin layer 70 may be a composite material in which two or more kinds of components are mixed. Furthermore, the constituent material of the resin layer 70 may include a non-resin material in an amount smaller than that of the resin material in addition to such a resin material.

  The thickness of the resin layer 70 affects the amount of expansion when the resin layer 70 expands as the first recess 711 and the second recess 721 expand in volume in a process described later. Therefore, when the thickness (volume expansion amount) of the first recess 711 or the second recess 721 is increased, the first recess 711 and the second recess 721 are formed by increasing the thickness of the resin layer 70. A sufficient amount of expansion of the resin layer 70 at the time of volume expansion can be ensured.

  Therefore, the thickness of the resin layer 70 before stretching is appropriately set according to the thickness (height) of the first recess 711 and the second recess 721 before and after volume expansion. As an example, the thickness is 30 μm or more and 3 mm. Or less, more preferably 50 μm or more and 2 mm or less. Thus, before the volume expansion, the resin has a mechanical strength enough to maintain the shape even if the first recess 711 is formed on the upper surface 71 side and the second recess 721 is formed on the lower surface 72 side. It can be applied to the layer 70. In addition, a sufficient extension amount can be imparted to the resin layer 70 during volume expansion.

  Next, the upper substrate 81 is overlaid on the upper surface 71 of the resin layer 70 so as to close the first recess 711. Thereby, the inside of the 1st recessed part 711 becomes a closed space. At this time, the contact interface between the upper surface 71 of the resin layer 70 and the upper substrate 81 is configured to have airtightness. As a result, the inside of the first recess 711 becomes a closed space having airtightness and becomes independent from the external space.

  On the other hand, the lower substrate 82 is overlaid on the lower surface 72 of the resin layer 70 so as to close the second recess 721. Thereby, the inside of the 2nd recessed part 721 also becomes a closed space. At this time, the contact interface between the lower surface 72 of the resin layer 70 and the lower substrate 82 is also configured to have airtightness. As a result, the inside of the second recess 721 becomes a closed space having airtightness and becomes independent from the external space.

  The constituent material of the upper substrate 81 and the constituent material of the lower substrate 82 are not particularly limited as long as each material has airtightness, and examples thereof include a resin material, a metal material, and a ceramic material.

  The bonding method between the resin layer 70 and the upper substrate 81 and the bonding method between the resin layer 70 and the lower substrate 82 are not particularly limited, and examples thereof include bonding with an adhesive and bonding with an adhesive sheet.

  As described above, a laminated substrate 8 is obtained in which the lower substrate 82, the resin layer 70, and the upper substrate 81 are laminated in this order (preparation step).

  [2] Next, as shown in FIG. 5A, the space in which the multilayer substrate 8 is placed, that is, the external space S of the multilayer substrate 8 is decompressed (decompression step). As a result, a pressure difference corresponding to the reduced pressure of the external space S is generated between the first recess 711 and the external space S and between the second recess 721 and the external space S, respectively.

  Based on this pressure difference, the first recess 711 and the second recess 721 are each accompanied by volume expansion. When the volume expands, the resin layer 70 is stretched mainly in the thickness direction. As a result, the first recess 711 and the second recess 721 each have an elongated internal space in the vertical direction of FIG.

  That is, when the first recess 711 expands in volume, as described above, it mainly expands downward in FIG. Also, when the second recess 721 expands in volume, it mainly expands upward in FIG.

  On the other hand, the first recess 711 and the second recess 721 expand in the left-right direction in FIG. 4 (in-plane direction of the resin layer 70), but are adjacent to each other when expanded by a certain amount. Since the second concave portions 721 adjacent to each other interfere with each other, they can expand only to their midpoint. Similarly, the first recess 711 and the second recess 721 also interfere with each other when expanded by a certain amount. For this reason, the expansion amount in the left-right direction in FIG. 4 is naturally limited.

  And when the 1st recessed part 711 and the 2nd recessed part 721 expand | swell to the limit which the resin layer 70 can extend, expansion | swelling stops. As a result, the thin resin layer 70 is separated between the first recess 711 and the second recess 721.

  Similarly, the first recess 711 also expands to the vicinity of the lower surface 72 of the resin layer 70 so as to separate the thin resin layer 70, and the second recess 721 also expands to the vicinity of the upper surface 71 of the resin layer 70 and is thin. The resin layer 70 is separated.

  From the above, the first recess 711 and the second recess 721 each have an elongated internal space in the vertical direction (thickness direction of the sacrificial layer 7), as shown in FIG. 6A.

  In addition, since the expansion of the first recess 711 and the second recess 721 proceeds isotropically, it is difficult to actually have an equal width shape as shown in FIG.

  FIG. 6B is an example of a plan view shape of the first recess 711 and the second recess 721 after volume expansion, and the sacrificial layer 7 shown in FIG. 6A is viewed from the upper surface 71 side. FIG.

  Since the first recess 711 expands isotropically, the opening is larger than before expansion. The adjacent first recesses 711 are separated from each other via the resin layer 70.

  On the other hand, the second recess 721 is expanded to a position directly below the upper surface 71, but its expansion end (portion shown in FIG. 6A) is delayed from the start of expansion of the first recess 711. Therefore, it is considered that the size of the second recess 721 in plan view is smaller than the size of the first recess 711 in plan view.

  FIG. 6B is an example, and differs depending on the shape of the first recess 711 and the second recess 721 before volume expansion, the constituent material of the resin layer 70, and the like.

  As described above, the first recess 711 and the second recess 721 each expand in volume mainly along the thickness direction of the resin layer 70. Therefore, as shown in FIG. 6A, in order to make each of the first recess 711 and the second recess 721 have an elongated shape, the first sacrificial layer 7 in plan view before being subjected to this step is used. It is preferable that the concave portion 711 and the second concave portion 721 do not overlap each other. In other words, the first recess 711 and the second recess 721 are displaced from each other when the sacrificial layer 7 before being subjected to this process is viewed through the lower surface 72 while the upper surface 71 is viewed in plan. Is preferred. Thereby, when the 1st recessed part 711 and the 2nd recessed part 721 each expand | swelled in the thickness direction of the resin layer 70, the expansion | swelling becomes difficult to mutually inhibit. As a result, the first concave portion 711 and the second concave portion 721 after volume expansion become long and narrow having a length close to the thickness of the resin layer 70, and each of the first concave portion 711 and the second concave portion 721 The aspect ratio can be increased.

  Such a first recess 711 serves as a mold that can mold the first liquid material 201 containing the active material forming material into an elongated shape (a shape with a large aspect ratio) in a process described later. By using the sacrificial layer 7 including the first recess 711 as described above, it is possible to finally obtain the active material molded body 2 capable of realizing the lithium secondary battery 100 having high output and high capacity.

  In addition, each arrangement | positioning of the 1st recessed part 711 and the 2nd recessed part 721 is not limited to what was mentioned above, For example, even if a part of 1st recessed part 711 and a part of 2nd recessed part 721 overlap. Good.

  The first recess 711 and the second recess 721 may be randomly arranged, but are preferably regularly arranged. Thereby, the volume of the first recess 711 per unit volume can be easily increased, and the volume of the second recess 721 adjacent to the first recess 711 can be easily increased at the same time. In other words, it becomes easy to bring these volumes close to the theoretical maximum value. In addition, the volume ratio between the first recess 711 and the second recess 721 can be easily adjusted. As a result, the contact area between the active material molded body 2 and the solid electrolyte layer 3 can finally be increased while increasing the filling rate of the active material molded body 2, and the capacity of the lithium secondary battery 100 can be increased. And high output.

  Note that the planar view shape of the first recess 711 and the planar view shape of the second recess 721 are not limited to the above-described shapes, and may be any shape such as a polygon, a circle, and an irregular shape.

  Further, one shape of the plurality of first recesses 711 may be different from the other one shape.

  Similarly, one shape of the plurality of second recesses 721 may be different from the other shape.

  [3] Next, as shown in FIG. 7A, the first liquid material 201 containing the active material forming material is put into the volume-expanded first recess 711 (filling step).

  Although the supply method of the 1st liquid material 201 is not specifically limited, What is necessary is just the method of flowing the 1st liquid material 201, the method using dispensers etc., the inkjet method, the spray method, the immersion method etc.

  When supplying the first liquid material 201, a through hole may be formed and supplied to the upper substrate 81. However, as shown in FIG. 7A, the upper substrate 81 is peeled and supplied. Also good.

  When the upper substrate 81 is peeled off, a part of the resin layer 70 may be cut using a cutting means such as a cutter, if necessary.

  Moreover, in order to make it easy to peel off the upper substrate 81, a release agent or the like may be applied to the upper surface 71 of the upper substrate 81 or the resin layer 70, or a release layer may be formed as necessary.

  In the case of FIG. 7A, since the first recess 711 is open on the upper surface 71 side, the first liquid material 201 is allowed to flow on the upper surface 71, thereby causing the first liquid material 201 to flow into the plurality of first recesses 711. It can be filled easily.

  In this filling operation, ultrasonic processing, vibration processing, or the like may be performed as necessary.

  Then, after filling the first liquid material 201 into the first recess 711, in this embodiment, as shown in FIG. 7B, the first liquid material 201 is further overflowed from the first recess 711. ing. Thereby, the first liquid materials 201 filled in the adjacent first recesses 711 are connected to each other. As a result, as shown in FIG. 7B, the first liquid material 201 can be spread so as to cover the upper surface 71 of the sacrificial layer 7.

  The first liquid material 201 spread in this way is finally converted into a layered active material molded body 2. This layered active material molded body 2 ensures a sufficiently large contact area with the current collector 1 and contributes to increasing the electronic conductivity during this time.

  In addition, after supplying the 1st liquid material 201, you may make it add the process of drying the 1st liquid material 201 as needed.

  Examples of the first liquid material 201 include a solution containing a precursor of an active material and a dispersion liquid in which active material particles 21 are dispersed in a dispersion medium. In such a first liquid material 201, the precursor is reacted to generate active material particles 21, or the dispersion medium is removed to leave the active material particles 21, thereby forming the active material with a desired molding pattern. The body 2 can be easily manufactured.

  The content of the active material particles 21 in the first liquid material 201 is preferably 10% by mass or more and 80% by mass or less, and more preferably 30% by mass or more and 70% by mass or less. Thereby, the active material molded object 2 which has a preferable porosity can be obtained.

  Moreover, you may add organic polymer compounds, such as a polyvinylidene fluoride (PVdF) and polyvinyl alcohol (PVA), as a binder to the 1st liquid material 201 as needed. These binders are burned or oxidized in the heat treatment described later, and the amount thereof is reduced.

  In addition, examples of the binder include polycarbonate, cellulose binder, acrylic binder, polyvinyl alcohol binder, polyvinyl butyral binder, and the like, and one or more of these can be used in combination. .

Moreover, you may add the particulate-form pore-forming material which uses a polymer or carbon powder as a forming material to the 1st liquid material 201 as needed. By mixing these pore formers, it becomes easy to control the porosity of the active material molded body 2. Such a pore former is decomposed and removed by combustion or oxidation during heat treatment, and the amount of the resulting active material molded body 2 is reduced.
The average particle diameter of the pore former is preferably 0.5 μm or more and 10 μm or less.

  Further, the first liquid material 201 may contain a photocurable resin as necessary. By including the photocurable resin, the first liquid material 201 has photocurability, and the shape retention can be improved by light irradiation.

  The photocurable resin includes, for example, a polymerizable compound and a photopolymerization initiator that can induce a polymerization reaction in the polymerizable compound.

  Among these, the polymerizable compound may be any compound that can be polymerized by the active species generated from the photopolymerization initiator, and examples thereof include various monomers and various oligomers. Specific examples include monomers and oligomers such as acrylic (methacrylic) s, epoxies, oxetanes, and vinyl ethers.

  The content of the polymerizable compound in the first liquid material 201 is not particularly limited, but is preferably 10% by mass or more and 80% by mass or less.

  On the other hand, the photopolymerization initiator may be any compound that generates active species such as radicals and cations upon irradiation with light. Examples thereof include aromatic ketones, acylphosphine oxide compounds, aromatic onium salt compounds, and organic peroxides. Thio compounds (thioxanthone compounds, thiophenyl group-containing compounds, etc.), hexaarylbiimidazole compounds, ketoxime ester compounds, borate compounds, azinium compounds, metallocene compounds, active ester compounds, compounds having a carbon halogen bond, alkylamine compounds, etc. And photocationic polymerization initiators such as sulfo radicals, diazonium salts and iodonium salts.

  Although content of the photoinitiator in the 1st liquid material 201 is not specifically limited, It is preferable that they are 0.5 mass% or more and 10 mass% or less.

  In addition, the first liquid material 201 includes, in addition to water, a dispersion medium (solvent) such as a protic solvent or an aprotic solvent, a dispersant such as oleylamine, a polymerization accelerator, and a polymerization inhibitor, as necessary. , Wetting agents, antioxidants, chelating agents, thickeners, sensitizers and the like may be added.

  Among these, as the dispersion medium (solvent), a dispersion medium containing one or more aprotic solvents such as butanol, ethanol, propanol, methyl isobutyl ketone, toluene, and xylene is particularly preferably used. By using such a dispersion medium, deterioration and deterioration of the active material particles 21 due to contact with the dispersion medium can be reduced.

  Further, the viscosity of the first liquid material 201 at room temperature (20 ° C.) is preferably 100 mPa · s or less, and more preferably 3 mPa · s or more and 10 mPa · s or less. Thereby, the high fluidity | liquidity of the 1st liquid material 201 and the low shrinkage rate at the time of solidification can be reconciled. As a result, the first liquid material 201 can be smoothly filled into the narrow first concave portion 711, and the porosity of the active material molded body 2 can be suppressed from becoming larger than necessary.

The viscosity is a value measured using, for example, an E type (cone plate type) viscometer, the temperature of the sample being 20 ° C., and the rotation speed of the cone spindle being 50 rpm.
Further, instead of the first liquid material 201, a powdered active material may be used.

  The pore-forming material of the powdery active material preferably contains deliquescent particles having a material having deliquescence as a forming material. Since the water generated around the deliquescent particles by the deliquescent particles functions as a binder for connecting the active material particles 21 together, the shape retention of the active material molded body 2 is improved. Therefore, the active material molded body 2 can be obtained without adding another binder or while reducing the amount of binder added, and the high-capacity electrode assembly 4 can be easily obtained.

  Examples of such deliquescent particles include particles using polyacrylic acid as a forming material.

  Moreover, it is preferable that the pore former further includes non-deliquescent particles having a material that does not have deliquescence as a forming material. The pore former containing such non-deliquescent particles is easy to handle. Further, if the pore former is only particles having deliquescence, the porosity of the active material molded body 2 may deviate from a desired set value depending on the amount of water around the pore former. By simultaneously including non-deliquescent particles as the pore material, it is possible to suppress the gap in porosity.

  [4] Next, in a state where the first liquid material 201 is filled in the first concave portion 711, a heat treatment is performed to heat them (heating step, see FIG. 7B). Thereby, the volatile component and organic component contained in the first liquid material 201 are removed. In addition, a reaction occurs in the precursor to produce a target compound. As a result, active material particles 21 are generated from the first liquid material 201. Further, the active material particles 21 are connected to each other by sintering, and are aggregated in a porous and columnar shape to generate an active material aggregate 25 (active material molded body 2) (see FIG. 8A).

  Moreover, the sacrificial layer 7 is thermally decomposed by this heating. Then, the decomposition product is removed as a gas. Thereby, the sacrificial layer 7 disappears, and so-called mold release is completed.

  According to the method as described above, the first concave portion 711 corresponding to the mold can be released regardless of the shape. For this reason, even when the shape of the first concave portion 711 is fine and complicated, it can be released without lowering the work efficiency, and the active material molded body 2 having the desired shape can be efficiently manufactured. Can do.

  Moreover, in said method, since the active material molded object 2 is not loaded at the time of mold release, a possibility that the active material molded object 2 may be damaged can be reduced. For this reason, for example, even if it is a case where the active material aggregate 25 with a large aspect ratio is included, the active material molded object 2 can be manufactured efficiently.

  This heat treatment is preferably performed at a processing temperature of 850 ° C. or higher and lower than the melting point of the lithium oxide to be used. Thereby, the molded object integrated by sintering the active material particles 21 can be obtained reliably. By performing heat treatment in such a temperature range, the resistivity of the obtained active material molded body 2 can be preferably 700 Ω / cm or less without adding a conductive auxiliary. Thereby, the obtained lithium secondary battery 100 is provided with sufficient output.

  Further, the heat treatment temperature is more preferably 875 ° C. or higher and 1000 ° C. or lower, and further preferably 900 ° C. or higher and 920 ° C. or lower.

  The heat treatment in the heating step is preferably performed for 5 minutes to 36 hours, and more preferably 4 hours to 14 hours.

  By performing the heat treatment as described above, the growth of grain boundaries in the active material particles 21 and the sintering between the active material particles 21 proceed, so that the resulting active material molded body 2 can easily maintain its shape, Even if the active material aggregate 25 having a large aspect ratio is included, the shape is hardly broken. Moreover, since a bond is formed between the active material particles 21 by sintering and an electron transfer path between the active material particles 21 is formed, the amount of the conductive additive added can also be suppressed.

  Furthermore, the heat treatment may be performed in multiple stages in which the temperature condition increases step by step. Specifically, after drying at room temperature, the temperature is increased from room temperature to 300 ° C. for 2 hours, to 350 ° C. for 0.5 hour, to 1000 ° C. over 2 hours, and then heated for another 8 hours. As an example. By raising the temperature under such conditions, for example, when a precursor is contained in the film, the reaction of the precursor can be first promoted, and then unnecessary components can be removed sequentially.

  The heat treatment may be performed once or may be performed in a plurality of times. By performing the heat treatment in such a plurality of times, for example, the reaction of the precursor and the sintering of the active material particles 21 and the sintering of the granular materials 31 can be performed reliably.

  [5] Next, as shown in FIG. 8B, the active material molded body 2 is accommodated in the container 9. Then, a second liquid material 301 containing an electrolyte forming material is placed in the container 9. Thereby, the second liquid material 301 enters the gap between the active material aggregates 25, in other words, the space where the second recess 721 of the sacrificial layer 7 was present. Therefore, the solid electrolyte layer 3 formed from the second liquid material 301 is substantially formed by the shape of the second recess 721. For this reason, the shape of the solid electrolyte layer 3 can be easily brought close to the intended shape.

  Therefore, for example, when the shape of the second recess 721 is an elongated shape, the electrolyte aggregate 35 having an elongated shape (a shape having a large aspect ratio) can be easily formed. Thereby, while increasing the filling rate of the solid electrolyte layer 3, the contact area between the active material molded body 2 and the solid electrolyte layer 3 can be increased, and the capacity and output of the lithium secondary battery 100 can be increased. The electrode assembly 4 that can be made compatible is obtained (see FIG. 10).

  The method for supplying the second liquid material 301 is not particularly limited, and is appropriately selected from the method for supplying the first liquid material 201 described above.

  In addition, when supplying the 2nd liquid material 301 in the container 9, in FIG. 9A, the 2nd liquid material 301 is supplied so that the upper surface of the active material molded object 2 may be exceeded. Thereby, when the solid electrolyte layer 3 is formed from the second liquid material 301, only the solid electrolyte layer 3 can be exposed to the other surface 4 b of the electrode assembly 4.

Examples of the second liquid material 301 include the following (A), (B), and (C).
(A) Solution (B) Inorganic solution containing a composition (a precursor of a solid electrolyte) having a metal atom contained in an inorganic solid electrolyte in a proportion according to the composition formula of the inorganic solid electrolyte and having a salt that becomes an inorganic solid electrolyte by oxidation Solution (C) Inorganic solid electrolyte fine particles, or metal having inorganic solid electrolyte, containing composition (precursor of solid electrolyte) having metal alkoxide containing metal atoms in solid electrolyte in proportion according to composition formula of inorganic solid electrolyte Dispersion medium or dispersion liquid in which fine particle sol containing atoms in proportion according to composition formula of inorganic solid electrolyte is dispersed in (A) or (B)

  In addition, the salt contained in (A) contains a metal complex. Moreover, (B) is a precursor in the case of forming an inorganic solid electrolyte using a so-called sol-gel method. In (A) and (B), the granular material 31 is produced | generated by reaction of a precursor, and in (C), the granular material 31 is produced | generated by removing a dispersion medium.

  From the viewpoint of increasing the final packing density of the solid electrolyte layer 3, a dispersion liquid in which inorganic solid electrolyte fine particles or fine particle sol is dispersed in (A) or (B) is preferably used.

  Further, the second liquid material 301 may contain a binder, a photocurable resin, a dispersion medium, and other components similar to those contained in the first liquid material 201 as necessary.

  In the state where the second liquid material 301 is impregnated in the pores of the active material molded body 2 as described above, heat treatment is performed to heat them (see FIG. 9B). Thereby, the volatile component and organic component contained in the second liquid material 301 are removed. In addition, a reaction occurs in the precursor to produce a target compound. As a result, the granular material 31 is generated from the second liquid material 301. In addition, the particulate bodies 31 are aggregated in a porous and columnar shape to generate an electrolyte aggregate 35 (solid electrolyte layer 3) (see FIG. 8A).

The heat treatment for the second liquid material 301 is performed at a lower temperature than the heat treatment for obtaining the active material molded body 2. Specifically, the heat treatment is preferably performed in a temperature range of 300 ° C. to 700 ° C. By this heat treatment, an inorganic solid electrolyte is generated from the precursor, and the solid electrolyte layer 3 is formed. As the material for forming the solid electrolyte _layer, it can be preferably used Li _{0.35 La} 0.55 TiO _3.

  By performing the heat treatment in such a temperature range, a solid-phase reaction occurs due to mutual diffusion of elements constituting each of the active material molded body 2 and the solid electrolyte layer 3, and an electrochemically inactive secondary agent is generated. It is possible to suppress the generation of organisms. Further, the crystallinity of the inorganic solid electrolyte is improved, and the ionic conductivity of the solid electrolyte layer 3 can be improved. In addition, a portion to be sintered is generated at the interface between the active material molded body 2 and the solid electrolyte layer 3, and charge transfer at the interface is facilitated. Thereby, the capacity | capacitance and output of a lithium battery using the electrode assembly 4 are improved.

  This heat treatment includes a first heat treatment for depositing the precursor on the surface of the active material molded body 2 and a second heat treatment for heating under a temperature condition not lower than the processing temperature of the first heat treatment and not higher than 700 ° C. It may be performed separately. By performing such stepwise heat treatment, the solid electrolyte layer 3 can be easily formed at a desired position.

  The viscosity of the second liquid material 301 at room temperature (20 ° C.) is preferably 100 mPa · s or less, and more preferably 3 mPa · s or more and 10 mPa · s or less. Thereby, the high fluidity | liquidity of the 2nd liquid material 301 and the low shrinkage rate at the time of solidification can be reconciled. As a result, the second liquid material 301 can be filled smoothly even in a narrow space, and an increase in the porosity of the solid electrolyte layer 3 can be suppressed.

  The viscosity is a value measured using, for example, an E type (cone plate type) viscometer, the temperature of the sample being 20 ° C., and the rotation speed of the cone spindle being 50 rpm.

In place of the second liquid material 301, a powdered solid electrolyte may be used.
The electrode composite 4 is obtained as described above.

Then, the manufacturing method of the lithium secondary battery 100 using the electrode assembly 4 is demonstrated.
[6] First, the laminate 10 is formed using the electrode assembly 4. The laminate 10 can be formed by bonding the current collector 1 to the electrode assembly 4. The laminate 10 can be used as a component on one electrode side of the battery.

The electrode composite 4 and the current collector 1 can be joined as follows.
By grinding and polishing one surface 4a of the electrode assembly 4, both the active material molded body 2 and the solid electrolyte layer 3 are exposed from the one surface 4a.

Next, as shown in FIG. 11, the current collector 1 is bonded to the one surface 4 a of the electrode assembly 4.
Thereby, the laminated body 10 provided with the active material molded object 2, the solid electrolyte layer 3, and the electrical power collector 1 is formed.

  The current collector 1 may be formed by joining a current collector formed as a separate body to the one surface 4a of the electrode assembly 4, and the conductive material described above is formed on the one surface 4a of the electrode assembly 4. It may be formed by filming.

  In addition, various physical vapor deposition methods (PVD) and chemical vapor deposition methods (CVD) can be used as a method for forming the current collector 1.

[7] Next, the lithium secondary battery 100 is formed using the laminate 10.
As described above, the laminate 10 is a component that can be used as one electrode of the battery, and the battery is obtained by joining the other electrode component to the other surface 4b of the electrode composite 4 included in the laminate 10. Can be formed. The battery in this embodiment is a lithium secondary battery. The lithium secondary battery 100 is formed through the following steps after the above-described steps.

  As shown in FIG. 11, the electrode 20 that is the other electrode component is joined to the other surface 4 b of the electrode assembly 4.

  The electrode 20 may be formed by bonding an electrode formed as a separate body to the other surface 4b of the electrode assembly 4, and by depositing the above-described conductive material on the other surface 4b of the electrode assembly 4. It may be formed.

  As the film formation method for the electrode 20, the same method as mentioned in the film formation method for the current collector 1 can be used.

Through the steps as described above, the lithium secondary battery 100 is manufactured.
In such a first manufacturing method, it is possible to form a recess having a large aspect ratio by simply reducing the pressure around the multilayer substrate 8 including the sacrificial layer 7 in which the recess is formed. As a forming material, the electrode assembly 4 including the active material aggregate 25 having a large aspect ratio, for example, can be efficiently manufactured.

  Further, by using the sacrificial layer 7 that can be decomposed by heating, a so-called mold release operation is not required, so that even the active material aggregate 25 having a large aspect ratio can be accurately manufactured.

  The filling rate of the active material molded body 2 can be easily increased, and the contact area between the active material molded body 2 and the solid electrolyte layer 3 can be easily increased. The secondary battery 100 can be manufactured efficiently.

  Next, the second embodiment of the lithium secondary battery of the present invention and the embodiment of the method of manufacturing the electrode composite of the present invention included therein will be described.

  12 and 13 are views for explaining a second manufacturing method of the lithium secondary battery shown in FIG.

  The second manufacturing method of the lithium secondary battery 100 includes [1] a step of preparing the sacrificial layer 7 including the first recessed portion 711 and the second recessed portion 721 that have undergone volume expansion in the same manner as the first manufacturing method; 2] Putting the first liquid material 201 containing the active material forming material into the first recess 711 and putting the second liquid material 301 containing the electrolyte forming material into the second recess 721; [3 The steps of decomposing and removing the sacrificial layer 7 by heating the sacrificial layer 7, the first liquid material 201 and the second liquid material 301, respectively, and obtaining the active material molded body 2 and the solid electrolyte layer 3; 4] A step of providing the current collector 1 and the electrode 20 in the same manner as in the first manufacturing method.

Hereinafter, each process will be described sequentially.
[1] First, the sacrificial layer 7 is prepared in the same manner as in the first manufacturing method. In order to support the sacrificial layer 7, a lower substrate 82 is disposed on the lower surface 72 of the sacrificial layer 7.

  The sacrificial layer 7 includes a resin layer 70, a first recess 711, and a second recess 721, as in the first manufacturing method. The resin layer 70 is mainly composed of a material that is decomposed and removed by heating, for example, a resin material.

  [2] Next, as shown in FIG. 12A, a first liquid material 201 containing an active material forming material is supplied into the volume-expanded first recess 711. At this time, as shown in FIG. 12A, the first liquid material 201 is allowed to overflow from the first recess 711. Thereby, the first liquid materials 201 filled in the adjacent first recesses 711 are connected to each other. As a result, the first liquid material 201 can be spread so as to cover the upper surface 71 of the sacrificial layer 7, and finally, the active material molded body 2 having a large contact area with the current collector 1 can be manufactured. it can.

  Thereafter, the first liquid material 201 is dried. Thereby, it is suppressed that the 1st liquid material 201 flows out.

  Subsequently, the sacrificial layer 7 is turned upside down. At the same time, the lower substrate 82 is peeled from the sacrificial layer 7, and the lower substrate 82 supports the lower surface of the dried body of the first liquid material 201 this time. Note that this support may be performed as necessary, and may be omitted.

  Further, when the lower substrate 82 is peeled from the sacrificial layer 7, a part of the resin layer 70 may be cut using a cutting means such as a cutter, if necessary.

  Moreover, in order to make it easy to peel the lower substrate 82, a release agent or the like may be applied to the lower substrate 82 or the lower surface 72 of the resin layer 70, or a release layer may be formed as necessary.

  Then, as shown in FIG. 12B, the second liquid material 301 containing the electrolyte forming material is supplied into the volume-expanded second recess 721. At this time, as shown in FIG. 12B, the second liquid material 301 is caused to overflow from the second recess 721. As a result, the second liquid materials 301 filled in the adjacent second recesses 721 are connected to each other. As a result, the second liquid material 301 can be spread so as to cover the lower surface 72 of the sacrificial layer 7, and finally the solid electrolyte layer 3 having a large contact area with the electrode 20 can be manufactured.

  Thereafter, the second liquid material 301 is dried. Thereby, it is suppressed that the 2nd liquid material 301 flows out.

  As described above, the first liquid material 201 can be filled in the first recess 711, and the second liquid material 301 can be filled in the second recess 721 (filling step, FIG. )reference).

  [3] Next, in a state where the first liquid material 201 is filled in the first concave portion 711 and the second liquid material 301 is filled in the second concave portion 721, heat treatment is performed to heat them (heating step) ).

  Thereby, active material particles 21 are generated from the first liquid material 201. Moreover, the active material particles 21 are connected to each other by sintering, and are aggregated in a porous and columnar shape to generate an active material aggregate 25 (active material molded body 2) (see FIG. 13B).

  On the other hand, the granular material 31 is generated from the second liquid material 301. The granular bodies 31 are also connected to each other, and are aggregated in a porous and columnar shape to generate an electrolyte aggregate 35 (solid electrolyte layer 3) (see FIG. 13B).

  In such a heat treatment, the formation of the active material molded body 2 and the formation of the solid electrolyte layer 3 can be performed simultaneously, so that the working efficiency can be improved as compared with the case where these are performed individually.

  This heat treatment sinters the active material particles 21, causes a portion to be sintered between the active material molded body 2 and the solid electrolyte layer 3, and causes deterioration of the solid electrolyte layer 3. Done under no processing conditions. Specifically, it may be appropriately set within the range of the heat treatment conditions described above according to the composition of the active material and the electrolyte.

  As described above, the electrode composite 4 including the active material molded body 2 and the solid electrolyte layer 3 is obtained.

[4] Next, in the same manner as in the first manufacturing method, the current collector 1 is joined to the one surface 4a of the electrode assembly 4, and the electrode 20 is joined to the other surface 4b of the electrode assembly 4. .
Thus, the lithium secondary battery 100 is manufactured.

  In such a second manufacturing method, it is possible to form a recess having a large aspect ratio by simply reducing the pressure around the laminated substrate 8 including the sacrificial layer 7 in which the recess is formed. By molding the forming material as described above, for example, the electrode composite 4 including the active material aggregate 25 having a large aspect ratio and the solid electrolyte layer 3 including the electrolyte aggregate 35 having a large aspect ratio can be efficiently manufactured.

  Further, by using the sacrificial layer 7 that can be decomposed by heating, a so-called mold release operation is not required, so that even the active material aggregate 25 having a large aspect ratio and the electrolyte aggregate 35 having a large aspect ratio can be accurately manufactured. can do.

  And the filling rate of the active material molded body 2 and the solid electrolyte layer 3 can be easily increased, and the contact area between the active material molded body 2 and the solid electrolyte layer 3 can be easily increased. The high-power lithium secondary battery 100 can be manufactured efficiently.

  In addition, the second manufacturing method has the same effects as the first manufacturing method, and the active material molded body 2 and the solid electrolyte layer 3 can be manufactured by a single heat treatment, so that the manufacturing efficiency is particularly high. There is also an effect.

(Second Embodiment)
In the present embodiment, a lithium secondary battery having a structure different from that of the first embodiment and a manufacturing method thereof will be described. In the following embodiments including this embodiment, the same number is assigned to the same component as the component in the first embodiment, and the description thereof may be omitted.

FIG. 14 is a longitudinal sectional view of the lithium secondary battery in the second embodiment.
In the lithium secondary battery 100 </ b> A, an electrode composite 4 </ b> A having a configuration different from that of the electrode composite 4 is provided to be joined to the current collector 1 and the electrode 20.

  That is, in the lithium secondary battery 100 </ b> A of the second embodiment, the electrode composite 4 </ b> A includes the active material molded body 2, the solid electrolyte layer 3, and the filled layer 30 filled in the voids remaining by the formation of the solid electrolyte layer 3. And have. In other words, the electrode assembly 4A further includes a filling layer 30 that is provided by filling the voids remaining in the electrode assembly 4 of the first embodiment.

The filling layer 30 is formed of a solid electrolyte that conducts lithium ions and is amorphous (glassy or amorphous) at room temperature. The filling layer 30 is formed of, for example, a lithium double oxide containing Si or B having lithium ion conductivity. Specifically, the filling layer 30 may include at least one of Li ₂ SiO ₃ and Li ₆ SiO ₅ .

  Such a packed bed 30 is heated after impregnating the remaining void with a precursor solution having fluidity of the packed bed 30, that is, a precursor solution of a solid electrolyte that is amorphous at room temperature, for example. It can be formed using a method.

In addition, as the filling layer 30, it is preferable to use a material that is solid (amorphous) at room temperature and has a volume shrinkage smaller than that of the solid electrolyte layer 3 when the precursor is fired. Moreover, it is preferable that the filling layer 30 can be formed at the same level as or lower than the solid electrolyte layer 3. This is to suppress mutual diffusion between the solid electrolyte layer 3 and the filling layer 30. For example, _Li 0.35 _La 0.55 TiO ₃ as the solid electrolyte layer 3, a case of using the _Li 2 SiO ₃ as the filling layer 30. In this case, the heating temperature at the time of forming the solid electrolyte layer 3 is about 700 ° C., but if the forming temperature at the time of forming the filling layer 30 exceeds 800 ° C., the solid electrolyte layer 3 and the filling layer 30 mutually Diffusion may occur. In addition, as the precursor of the filling layer 30, any one of the above-described (A) to (C) can be cited as in the case of the precursor of the solid electrolyte layer 3. This is diluted with a solvent (for example, an alcohol compound) to obtain a precursor solution. This precursor solution is impregnated into the remaining voids. The method for impregnating the precursor solution is the same as that described for the solid electrolyte layer 3.

  Moreover, the heating temperature which heats the precursor solution with which the space | gap was filled is set to 300 to 450 degreeC, for example.

(Third embodiment)
In the present embodiment, a lithium secondary battery having a structure different from that of the first embodiment and the second embodiment and a manufacturing method thereof will be described.

FIG. 15 is a longitudinal sectional view of a lithium secondary battery according to the third embodiment.
In the lithium secondary battery 100 </ b> B, an electrode composite 4 </ b> B having a configuration different from that of the electrode composite 4 is provided to be joined to the current collector 1 and the electrode 20.

  That is, in the lithium secondary battery 100B of the third embodiment, the electrode assembly 4B includes the active material molded body 2, the solid electrolyte layer 3, and the electrolytic solution 36 filled in the voids remaining due to the formation of the solid electrolyte layer 3. And an electrolyte-impregnated layer 37 that joins both of them between the solid electrolyte layer 3 and the electrode 20. In other words, the electrode assembly 4 </ b> B is provided between the electrode assembly 4 and the electrode 20, and the electrolytic solution 36 provided by filling the voids remaining in the electrode assembly 4 of the first embodiment. The electrolyte solution impregnated layer 37 is further provided.

  In this electrode complex 4B, an electrolyte solution impregnated layer 37 is provided between the electrode complex 4 and the electrode 20, and the electrolyte solution 36 is supplied to the remaining space from the electrolyte solution impregnated layer 37 to fill the electrode complex 4B. Is done. As a result, the contact area between the active material molded body 2 and the solid electrolyte layer 3 is prevented from decreasing in the gap, and the resistance between the active material molded body 2 and the solid electrolyte layer 3 is increased. Thus, it is possible to reliably prevent the ion conductivity between the active material molded body 2 and the solid electrolyte layer 3 from being lowered.

  In general, when the charge / discharge cycle is repeated in the lithium secondary battery, the volume of the active material molded body or the solid electrolyte layer may vary. On the other hand, in the present embodiment, for example, even when the volume shrinks and the voids widen, the electrolytic solution further oozes out from the electrolytic solution impregnated layer 37 and the voids are filled with the electrolytic solution 36. On the other hand, even if the volume is increased and the gap is narrowed, the electrolyte solution 36 in the gap is immersed in the electrolyte solution impregnated layer 37. As described above, the gap of the electrode assembly 4B becomes a buffer space that absorbs the volume fluctuation, and leads to securing of a charge conduction path. That is, a high output battery can be obtained.

  Note that since the electrolytic solution 36 (ionic liquid in the electrolytic solution-impregnated layer) is small and non-volatile, there is no problem of liquid leakage and combustion.

  The electrolyte solution impregnated layer 37 is a film that functions as a supply source of a lithium-resistant film and a polymer gel electrolyte. The electrolytic solution impregnated layer 37 is a film impregnated with an electrolytic solution that conducts lithium ions. That is, the electrolytic solution impregnated layer 37 includes a support and a polymer gel electrolyte (electrolytic solution).

  The support is for physically supporting the structure of the electrolyte-impregnated layer (PEG film) 37. The support preferably does not precipitate impurities, does not react with other materials such as a polymer gel electrolyte, and has high wettability with ionic liquid + Li salt + monomer. If impurities are deposited or a chemical reaction occurs, the characteristics may change. Further, when the wettability is poor, there is a possibility that the polymer cannot be formed uniformly on the support. It is possible to improve the strength by increasing the ratio of the polymer component in the polymer gel electrolyte without using the support, but increasing the ratio of the polymer component causes a decrease in the conductivity of Li, so use the support. Is preferred. As the support, for example, long fiber cellulose or hydrophobic PVDF (polyvinylidene fluoride) is used.

  The polymer gel electrolyte is required to have a property that is chemically stable to Li and can be gelled to hold an electrolytic solution. A normal PEG (polyethylene glycol) film becomes a lithium-resistant reduction layer that suppresses reduction, and battery operation can be confirmed. However, the PEG film cannot be expected to improve ion conductivity, and there is a possibility that a practical output as a battery cannot be obtained. In order to obtain a practical output as a battery, it is necessary to improve the conductivity of Li. Therefore, in this embodiment, a gel polymer electrolyte that does not volatilize the electrolyte is used.

  In such an electrode assembly 4B, for example, the electrolyte solution impregnated layer 37 is attached to one surface of the composite body of the active material molded body 2 and the solid electrolyte layer 3 in which voids remain, whereby the electrolyte solution impregnated layer 37 The electrolyte solution can be formed using a method of supplying the electrolyte solution to the gap.

  The electrolytic solution-impregnated layer 37 is produced, for example, by impregnating a support (base material) with a precursor solution containing an electrolytic solution and a monomer and photopolymerizing it. The electrolytic solution includes an ionic liquid and a lithium salt. As the ionic liquid, for example, P13-TFSI (N-methyl-N-propylpyrrolidinium bis (trifluoromethanesulfonyl) imide) is used. As the lithium salt, Li-TFSI (lithium N, N-bis (trifluoromethanesulfonyl) imide) is used. For example, polyethylene glycol diacrylate (TEGDA) is used as the monomer. A polymerization initiator and ethylene carbonate are mixed in the above electrolytic solution to obtain a PGE preparation solution. As the polymerization initiator, for example, a radical photopolymerization initiator (for example, IRGACURE651,2,2-dimethoxy-1,2-diphenylethane-1-one manufactured by BASF) is used. The polymerization initiator is mixed at a mixing ratio of, for example, 6: 1 by weight. Ethylene carbonate is used as a SEI (Solid Electrolyte Interface) forming material. SEI is a coating that inactivates and stabilizes the surface of the Li electrode. SEI is produced by a reductive decomposition reaction of the electrolytic solution, and it has been confirmed that charges are consumed by the decomposition reaction of ethylene carbonate in the first cycle. Ethylene carbonate is mixed at a mixing ratio of 1. The support is impregnated with this PGE preparation solution. As the support, for example, a hydrophobic PVDF membrane filter manufactured by MILLIPORE is used. The support impregnated with the PGE preparation solution is irradiated with light of a predetermined wavelength band (for example, ultraviolet light) to photopolymerize the monomer and polymerize to obtain the electrolyte-impregnated layer 37. The electrolytic solution contained in the electrolytic solution-impregnated layer 37 is filled in the remaining gap and functions as the electrolytic solution 36.

The electrolyte contained in the electrolyte-impregnated layer 37 has good wettability to the solid electrolyte (Li _0.35 La _0.55 TiO ₃ ), and soaks in the remaining voids along the solid electrolyte layer 3. As a result, the electrolyte solution 36 is filled in the gap.

(Fourth embodiment)
In the present embodiment, a lithium secondary battery having a structure different from those in the first to third embodiments and a method for manufacturing the lithium secondary battery will be described.

FIG. 16 is a longitudinal sectional view of a lithium secondary battery according to the fourth embodiment.
In the lithium secondary battery 100 </ b> C, an electrode composite 4 </ b> C having a configuration different from that of the electrode composite 4 is provided to be joined to the current collector 1 and the electrode 20.

  The electrode composite 4 </ b> C includes an active material molded body 2 having active material particles 21 and noble metal particles 22, and a solid electrolyte layer 3.

  The noble metal particles 22 are in the form of particles, and are attached to the surfaces of a plurality of active material particles 21 connected to each other or interposed between the active material particles 21.

  Thereby, the noble metal particles 22 are interposed in the transfer of electrons between the plurality of active material particles 21 and the transfer of lithium ions between the active material particles 21 and the solid electrolyte layer 3, and these can be performed more smoothly. Will be able to. Furthermore, the transfer of electrons between the plurality of active material particles 21 and the transfer of lithium ions between the active material particles 21 and the solid electrolyte layer 3 are stably maintained over a long period of time. Therefore, by applying the electrode assembly 4C having such a configuration to the lithium secondary battery 100C, the lithium secondary battery 100C can stably maintain a high output and a high capacity over a long period of time. The noble metal particles 22 preferably contain a noble metal having a melting point of 1000 ° C. or higher as a forming material (constituent material).

  The noble metal having a melting point of 1000 ° C. or higher is not particularly limited, but gold (Au; melting point 1061 ° C.), platinum (Pt; melting point 1768 ° C.), palladium (Pd; melting point 1554 ° C.), rhodium (Rh; melting point 1964 ° C.) ), Iridium (Ir; melting point 2466 ° C.), ruthenium (Ru; melting point 2334 ° C.), osmium (Os; melting point 3033 ° C.), and these metals can be used alone, or alloys of these metals are used. You may do it. Among these, at least one of platinum and palladium is preferable. These noble metals are relatively inexpensive and easy to handle among the noble metals, and are excellent in lithium ion and electron conductivity. Therefore, by using it as a constituent material of the noble metal particles 22, the transfer of electrons between the plurality of active material particles 21 and the transfer of lithium ions between the active material particles 21 and the solid electrolyte layer 3 are performed more smoothly. And capable of being more stably maintained over a long period of time.

  The noble metal particles 22 preferably have an average particle size of 0.1 μm to 10 μm, and more preferably 0.1 μm to 5 μm. The average particle diameter of the noble metal particles 22 can be measured using the same method as that for measuring the average particle diameter of the active material particles 21.

  Furthermore, the content of the noble metal particles 22 in the active material molded body 2 is preferably 0.1% by mass or more and 10% by mass or less, and more preferably 1% by mass or more and 10% by mass or less.

  By setting the average particle size and content of the noble metal particles 22 within the above ranges, the noble metal particles 22 can be more reliably attached to the surface of the active material particles 21 or between the active material particles 21. It becomes possible to intervene. As a result, the transfer of electrons between the plurality of active material particles 21 and the transfer of lithium ions between the active material particles 21 and the solid electrolyte layer 3 can be performed more smoothly, and over a long period of time. It becomes possible to maintain it stably.

  Such an active material molded body 2 can be manufactured, for example, by adding the noble metal particles 22 together with the active material particles 21 to the first liquid material 201 in the above-described method for manufacturing a lithium secondary battery.

  As mentioned above, although the manufacturing method of the active material molded object of this invention, the manufacturing method of an electrode composite_body | complex, and the manufacturing method of a lithium battery were demonstrated based on embodiment of illustration, this invention is not limited to this.

  For example, one or more arbitrary steps may be added to the method for producing an active material molded body, the method for producing an electrode assembly, and the method for producing a lithium battery according to the present invention, respectively.

  Moreover, the manufacturing method of the lithium battery containing the manufacturing method of the active material molded object of this invention is applicable also to manufacture of the lithium battery containing a liquid electrolyte.

  Moreover, the manufacturing method of the lithium battery of this invention is applicable also to manufacture of a primary battery other than manufacture of the lithium secondary battery demonstrated in the said each embodiment.

  Moreover, the electrode composite manufactured by the method for manufacturing an electrode composite of the present invention has a configuration in which two or more configurations of the electrode composite manufactured in each embodiment described above are arbitrarily combined. Also good.

  Moreover, the shape of the 1st recessed part and 2nd recessed part which the sacrificial layer in each said embodiment contains is not limited to what was mentioned above.

  FIG. 17 is a plan view of the sacrificial layer 7 according to another configuration example seen from the upper surface 71 (first surface) side to the lower surface 72 (second surface) side. In FIG. 17, the same reference numerals are given to the same components as those in the first embodiment described above. In FIG. 17, dots are added to the recesses of the sacrificial layer.

  In the sacrificial layer 7 shown in FIG. 17A, when the lower surface 72 is seen through from the upper surface 71, the first recess 711 and the second recess 721 each form a regular hexagon. The plurality of first recesses 711 are arranged in a row, and the plurality of second recesses 721 are also arranged in a row.

  On the other hand, when the sacrificial layer 7 shown in FIG. 17B is seen through the lower surface 72 from the upper surface 71, the first recess 711 and the second recess 721 each have a regular hexagonal shape. A plurality of second recesses 721 are arranged apart from each other. Further, the plurality of first recesses 711 are arranged between the second recesses 721.

As described above, in the present invention, it is possible to set arbitrary shapes for the first recess 711 and the second recess 721 of the sacrificial layer 7. And by using such a sacrificial layer 7, the active material molded body 2 and the solid electrolyte layer 3 molded in an arbitrary molding pattern can be easily manufactured.
Note that the present invention can be widely applied without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 1 Current collector 2 Active material molded object 3 Solid electrolyte layer 4 Electrode complex 4A Electrode complex 4B Electrode complex 4C Electrode complex 4a One side 4b Other side 7 Sacrificial layer 8 Laminated substrate 9 Container 10 Laminated body 20 Electrode 21 Active material Particle 22 Precious metal particle 25 Active material aggregate 30 Filling layer 31 Granule 35 Electrolyte aggregate 36 Electrolytic solution 37 Electrolytic solution impregnated layer 70 Resin layer 71 Upper surface 72 Lower substrate 81 Lower substrate 100 Lithium secondary battery 100A Lithium secondary battery 100B Lithium secondary battery 100C Lithium secondary battery 201 First liquid material 301 Second liquid material 711 First recess 721 Second recess S External space

Claims (12)

A sacrificial layer having a first surface and a second surface facing each other, a plurality of first recesses opening in the first surface, and a plurality of second recesses opening in the second surface When,
A first lid for closing the opening of the first recess;
A preparation step of preparing a second lid portion that closes the opening of the second recess;
Decompressing the sacrificial layer by deforming the sacrificial layer by decompressing the space in which the sacrificial layer is placed and expanding the volume of the first recess and the volume of the second recess, respectively;
A filling step of placing an active material forming material in the first recess;
A heating step of decomposing and removing the sacrificial layer by heating the sacrificial layer and the active material forming material, and obtaining an active material molded body;
The manufacturing method of the active material molded object characterized by including.   2. The method for producing an active material molded body according to claim 1, wherein the first concave portion and the second concave portion are displaced from each other when the first surface is viewed in plan while seeing through the second surface. .   The active part according to claim 1 or 2, wherein, when the first surface is viewed in plan while seeing through the second surface, the first recess and the second recess are regularly arranged. A method for producing a molded material.   In the filling step, after the first lid portion is removed from the sacrificial layer, the active material forming material is placed in each of the first recesses, and is placed in two adjacent first recesses. The manufacturing method of the active material molded object of any one of Claim 1 thru | or 3 which connects the forming material of the said active material.   The method for producing an active material molded body according to any one of claims 1 to 4, wherein the constituent material of the sacrificial layer includes a resin material. A sacrificial layer having a first surface and a second surface facing each other, a first recess opening in the first surface, and a second recess opening in the second surface;
A first lid for closing the opening of the first recess;
A preparation step of preparing a second lid portion that closes the opening of the second recess;
Decompressing the sacrificial layer by deforming the sacrificial layer by decompressing the space in which the sacrificial layer is placed and expanding the volume of the first recess and the volume of the second recess, respectively;
A filling step of placing an active material forming material in the first recess and an electrolyte forming material in the second recess;
Heating the sacrificial layer, the active material forming material, and the electrolyte forming material, respectively, to decompose and remove the sacrificial layer and obtain an active material molded body and a solid electrolyte layer;
A method for producing an electrode composite comprising:   The method for manufacturing an electrode assembly according to claim 6, wherein the first concave portion and the second concave portion are displaced from each other when the first surface is viewed in plan while seeing through the second surface.   The electrode according to claim 6 or 7, wherein the first recess and the second recess are regularly arranged when the first surface is viewed in plan while seeing through the second surface. A method for producing a composite. In the filling step,
After removing the first lid from the sacrificial layer, the active material forming material is placed in each of the first recesses, and the active material is formed in two adjacent first recesses. While connecting materials together,
After the second lid portion is removed from the sacrificial layer, the electrolyte forming material is put into each of the second recesses, and the electrolyte forming materials are put into two adjacent second recesses. The method for producing an electrode assembly according to any one of claims 6 to 8.   The method for producing an electrode assembly according to claim 6, wherein the constituent material of the sacrificial layer includes a resin material. Providing an electrolyte layer in contact with the active material molded body produced by the method for producing an active material molded body according to any one of claims 1 to 5,
Providing a current collector in contact with the active material molded body;
Providing an electrode in contact with the electrolyte layer;
A method for producing a lithium battery, comprising: A step of providing a current collector on one surface of the electrode composite manufactured by the method for manufacturing an electrode composite according to any one of claims 6 to 10 so as to be in contact with the active material molded body,
Providing an electrode composition on the other surface of the electrode composite;
A method for producing a lithium battery, comprising:

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