JP2021015779A - Secondary battery and method for manufacturing the same - Google Patents

Abstract

To provide a secondary battery capable of suppressing leakage of an active material from the inside of an electrode to the outside thereof, and a method for manufacturing the same.SOLUTION: A secondary battery 1 has a single cell 11 including a first electrode 2, a separator 3 which is formed of a solid electrolyte having carrier ion conductivity and laminated on the first electrode 2, and a second electrode 4 laminated on the separator 3. The first electrode 2 has a reaction portion 21, and a hole sealing portion 22 arranged at least partially around a reaction portion 21 in plan view when viewed in a lamination direction of the single cell 11. The reaction unit 21 includes a porous body 23 which is formed of a solid electrolyte having carrier ion conductivity and has pores, and an active material 211 held in the pores 231 of the porous body 23. The hole sealing portion 22 has the porous body 23 and the sealing material 221 with which the pores 231 of the porous body 23 is filled.SELECTED DRAWING: Figure 1

Description

The present invention relates to a secondary battery and a method for manufacturing the same.

As a battery for an automobile or an electronic device, a secondary battery such as a lead storage battery, a nickel hydrogen storage battery, or a lithium ion secondary battery in which an electrolytic solution is interposed between a positive electrode and a negative electrode is used. In recent years, in order to further improve safety as compared with these secondary batteries, a so-called all-solid-state battery in which a solid electrolyte is interposed between a positive electrode and a negative electrode has been proposed.

For example, Patent Document 1 describes a plate-shaped dense body made of ceramics containing a solid electrolyte and ceramics containing a solid electrolyte that is the same as or different from the solid electrolyte of the dense body, and at least one surface of the dense body. A solid electrolyte structure for an all-solid-state battery having a porous layer formed by firing and integrating with the above is described. By filling the pores of the porous layer in this solid electrolyte structure with an active material, an all-solid-state battery using the porous layer as an electrode can be formed.

International Publication No. 2008/059987

In the solid electrolyte structure of Patent Document 1, when the active material is filled in the pores of the porous layer, the active material in a molten state, the slurry of the active material, the active material such as the sol of the active material precursor, or the active material is active. Liquids of material precursors are used. However, since the pores are open on the outer surface of the porous layer, when the liquid of the active material or the active material precursor is filled in the pores, the liquid may leak to the outside of the porous layer from the above-mentioned opening. There is.

The present invention has been made in view of such a problem, and an object of the present invention is to provide a secondary battery capable of suppressing leakage of an active material from the inside of an electrode to the outside and a method for manufacturing the same.

One aspect of the present invention includes a first electrode (2, 202 to 205) and
The separator (3) laminated on the first electrode and
It has a single cell (11) provided with a second electrode (4, 402) laminated on the separator.
The first electrode is
A reaction unit (23) comprising a porous body (23) made of a solid electrolyte having carrier ion conductivity and having pores, and an active material (211) held in the pores (231) of the porous body. 21) and
The porous body and the sealing material (221) filled in the pores of the porous body, which are arranged at least a part around the reaction portion in a plan view seen from the stacking direction of the single cell, A secondary battery (1, 102-106) having a sealing portion (22) and the like.

Another aspect of the present invention is the method for manufacturing a secondary battery according to the above aspect.
A laminating step of producing a laminated body (10) including a porous body (23) made of a solid electrolyte having carrier ion conductivity and having pores, and the separator laminated on the porous body.
A sealing step of filling at least a part of the pores existing in the peripheral edge of the porous body in a plan view from the stacking direction of the laminated body with a sealing material (221) to form the sealing portion. When,
An active material filling step of filling the pores with the active material (211) or a precursor thereof so as to move from the outside of the porous body toward the sealing portion to form the reaction portion. It is in the method of manufacturing a secondary battery.

The first electrode in the secondary battery has the reaction portion provided with the active material and the sealing portion arranged at least a part around the reaction portion. Further, the sealing portion has the porous body and a sealing material filled in the pores of the porous body. In this way, by arranging the sealing portion whose pores are closed by the sealing material around the reaction portion, the active material that tends to move from the inside to the outside of the porous body is dammed up in the sealing portion. be able to. As a result, leakage of the active material from the inside of the first electrode to the outside can be suppressed.

Further, in the manufacturing method of the above aspect, after the laminated body is produced, the pores existing in the peripheral portion of the porous body are filled with the sealing material to form the sealing portion. The active material or a precursor thereof is then filled into the pores so as to move toward the sealing portion. Since the pores of the sealing portion are closed by the sealing material, the sealing portion can suppress the entry of the active material or the like into the sealing portion. As a result, it is possible to suppress the leakage of the active material from the inside to the outside of the first electrode in the process of manufacturing the secondary battery.

As described above, according to the above aspect, it is possible to provide a secondary battery capable of suppressing leakage of the active material from the inside of the electrode to the outside and a method for manufacturing the secondary battery.
The reference numerals in parentheses described in the scope of claims and the means for solving the problem indicate the correspondence with the specific means described in the embodiments described later, and limit the technical scope of the present invention. It's not a thing.

FIG. 1 is a perspective view of the secondary battery according to the first embodiment. FIG. 2 is a cross-sectional view taken along the line II-II of FIG. FIG. 3 is a schematic view of the active material filling step in the production method of the first embodiment. FIG. 4 is a perspective view of a secondary battery in the second embodiment in which a sealing portion is provided along two adjacent sides of the first electrode. FIG. 5 is a perspective view of a secondary battery in the second embodiment in which a sealing portion is provided along two opposite sides of the first electrode. FIG. 6 is a perspective view of the secondary battery in the second embodiment in which the sealing portions are provided along the three sides of the first electrode. FIG. 7 is a perspective view of a secondary battery in the second embodiment in which a sealing portion is provided along the entire outer circumference of the first electrode. FIG. 8 is a plan view of the secondary battery according to the third embodiment as viewed from the second electrode side. FIG. 9 is a cross-sectional view taken along the line IX-IX of FIG.

(Embodiment 1)
An embodiment relating to the secondary battery and a method for manufacturing the secondary battery will be described with reference to FIGS. 1 to 3. As shown in FIG. 1, the secondary battery 1 according to the present embodiment has a first electrode 2, a separator 3 composed of a solid electrolyte having carrier ion conductivity and laminated on the first electrode 2, and a separator 3 on the separator 3. It has a single cell 11 including a laminated second electrode 4. The first electrode 2 has a reaction portion 21 and a sealing portion 22 arranged at least a part around the reaction portion 21 in a plan view seen from the stacking direction of the single cell 11. As shown in FIG. 2, the reaction unit 21 includes a porous body 23 made of a solid electrolyte having carrier ion conductivity and having pores 231 and an active material 211 held in the pores 231 of the porous body 23. ,have. The sealing portion 22 has a porous body 23 and a sealing material 221 filled in the pores 231 of the porous body 23.

The secondary battery 1 may have one single cell 11 or may have a plurality of single cells 11. For example, the secondary battery 1 of this embodiment has one single cell 11. As shown in FIG. 2, a current collector 12 is laminated on the surface of the first electrode 2 and the surface of the second electrode 4 in the single cell 11, respectively. The secondary battery 1 can be charged or discharged by adding or connecting a power generation device to these current collectors 12. As the current collector 12, for example, a composite material in which a conductive powder such as carbon or a conductive oxide is dispersed in a conductor such as a metal foil or a metal plate or an insulator such as glass can be used. .. In FIG. 1, the description of the current collector 12 is omitted for convenience.

Although not shown in the figure, when the secondary battery 1 has a plurality of single cells 11, a plurality of current collectors 12 and a plurality of single cells 11 are alternately superposed on the current collectors 12 via the current collectors 12. The single cell 11 can be electrically connected. For example, by superimposing the current collector 12 and the single cell 11 so that one surface of the current collector 12 is in contact with the first electrode 2 and the other surface is in contact with the second electrode 4. A plurality of single cells 11 can be connected in series. Further, by superimposing the current collector 12 and the single cell 11 so that the current collector 12 is interposed between the electrodes 2 and 4 of the same type, a plurality of single cells 11 can be connected in parallel. ..

The first electrode 2 may be a positive electrode or a negative electrode. Specifically, the first electrode 2 of this embodiment is a positive electrode.

Further, the shape of the first electrode 2 can take various forms. For example, as shown in FIG. 1, the first electrode 2 of the present embodiment has a rectangular plate shape formed by the porous body 23.

As shown in FIG. 2, the reaction portion 21 of the first electrode 2 has a porous body 23 and an active material 211 held in the pores 231 of the porous body 23. In addition to the active material 211, other solid electrolytes and liquid electrolytes different from the solid electrolyte constituting the conductive auxiliary agent and the porous body 23 may be held in the pores 231 of the reaction unit 21.

The porous body 23 is composed of a solid electrolyte having carrier ion conductivity and electrical insulation. Therefore, the carrier ions desorbed from the active material 211 can move to the second electrode 4 via the solid electrolyte. Further, the carrier ions supplied from the second electrode 4 can move to the active material 211 via the solid electrolyte and react with the active material 211. In this way, the solid electrolyte constituting the porous body 23 serves as a path for carrier ions, so that the secondary battery 1 can be charged and discharged.

As the solid electrolyte, a substance in which carrier ions can move can be used. For example, when the carrier ion is Li ⁺ , a garnet-type solid electrolyte such as lithium lanthanozirconate, or a NASICON-type solid electrolyte such as aluminum-substituted lithium titanium phosphate (that is, LATP) or aluminum-substituted germanium lithium phosphate (that is, LAGP). , Lithium lanthanum titanate (that is, LLTO) or the like, a perovskite type solid electrolyte or the like can be used. As the garnet-type solid electrolyte, in addition to lithium lanthanum zirconate, lithium lanthanum zirconate is doped with one or more dopants selected from calcium, niobium, aluminum, tantalum, strontium, barium, yttrium and the like. It is also possible to adopt the solid electrolyte obtained. Specifically, the porous body 23 of this embodiment is composed of a garnet-type solid electrolyte.

The porous body 23 has pores 231 for holding the active material 211 and the sealing material 221. The pores 231 of the porous body 23 may have a continuous pore structure, for example, as shown in FIG. The porosity of the porous body 23 can be, for example, 20 to 80%. The porosity of the porous body 23 is a value calculated based on a three-dimensional reconstruction image obtained by a FIB / SEM (that is, a focused ion beam / scanning electron microscope) tomography method. More specifically, processing of the sample by the FIB device and observation of the processed surface by SEM are repeated to acquire a plurality of SEM images. By reconstructing these SEM images on image analysis software, a three-dimensional reconstructed image of the sample is obtained. Then, the obtained three-dimensional reconstructed image is subjected to a binarization treatment so that the boundary between the solid electrolyte portion forming the skeleton of the porous body 23 and the rest is not impaired. In the binarized image obtained as described above, the ratio of the occupied volume of the portion other than the solid electrolyte portion in the porous body 23 is defined as the porosity.

The active material 211 can be appropriately selected depending on the carrier ions and the polarities of the first electrode 2. For example, when the carrier ion is lithium ion (Li ⁺ ) and the first electrode 2 is the positive electrode, the active material 211 of the first electrode 2 is composed of a sulfur-based active material containing a sulfur atom or an oxide. Oxide-based active materials can be used. Examples of the sulfur-based active material, specifically, simple and lithium sulfide sulfur (Li ₂ S), can be lithium using doped sulfur and the like. Specific examples of the oxide-based active material include lithium cobalt oxide (LiCoO ₂ ), LiNi _1/3 Mn _1/3 Co _1/3 O ₂ , lithium manganate (LiMnO ₂ ), and lithium iron phosphate (LiFePO). ₄ ) etc. can be used.

When the first electrode 2 is a positive electrode, it is preferable that the active material 211 contains a sulfur atom. In this case, the capacity of the secondary battery 1 can be increased. Specifically, the active material 211 in the reaction unit 21 of the present embodiment is a simple substance of sulfur.

When the carrier ion is Li ⁺ and the first electrode 2 is the negative electrode, metallic lithium, carbon, Li ₄ Ti ₅ O _12, or the like can be used as the active material 211 of the first electrode 2.

The sealing portion 22 is connected to the edge of the reaction portion 21 in a plan view seen from the stacking direction of the single cell 11. The sealing portion 22 may be arranged so as to surround the reaction portion 21 in a plan view viewed from the stacking direction of the single cells 11, or may be arranged in a part around the reaction portion 21. For example, as shown in FIG. 1, the sealing portion 22 of the present embodiment is arranged along one long side 232 of the porous body 23 in a plan view seen from the stacking direction of the single cells 11.

The porous body 23 of the sealing portion 22 in this embodiment is integrally formed with the porous body 23 of the reaction portion 21. That is, in the first electrode 2, the portion where the active material 211 is held in the pores 231 of the porous body 23 becomes the reaction portion 21, and the portion where the pores 231 are filled with the sealing material 221 is the sealing portion. It becomes part 22.

In the sealing portion 22, the sealing material 221 may be filled in all of the pores 231 of the porous body 23, or the sealing material 221 may be filled in a part of the pores 231. From the viewpoint of more effectively suppressing the entry of the active material 211 into the sealing portion 22, the porosity of the sealing portion 22 is preferably 10% or less, and more preferably 5% or less.

The porosity of the sealing portion 22 is a three-dimensional reconstructed image obtained by the FIB / SEM (that is, focused ion beam / scanning electron microscope) tomography method, similarly to the porosity of the porous body 23 described above. It is a value calculated based on this.

The sealing material 221 can be filled in the pores 231 and may be composed of any substance as long as the pores 231 can be closed. For example, the sealing material 221 may be a conductor such as metal, or an insulator such as glass or ceramics. Further, the sealing material 221 may be an organic material such as rubber or plastic. Further, as the sealing material 221, a substance having carrier ion conductivity can also be used. For example, the sealing material 221 of this embodiment is specifically silica glass.

The sealing material 221 is preferably composed of a substance that can maintain its shape when heated to the melting point of the active material 211 of the first electrode 2. That is, for example, when the sealing material 221 has a melting point or a softening point, it is preferable that the melting point or the softening point of the sealing material 221 is higher than the melting point of the active material 211. When the sealing material 221 is a substance that thermally decomposes, it is preferable that the thermal decomposition temperature of the sealing material 221 is higher than the melting point of the active material 211. In this case, in the process of manufacturing the secondary battery 1, when the active material 211 in the molten state is filled in the pores 231 of the porous body 23, the active material 211 can be reliably dammed by the sealing material 221. it can. As a result, the leakage of the active material 211 can be suppressed more reliably.

Further, the sealing material 221 preferably has electrical insulation. The first electrode 2 and the second electrode 4 may deviate from a desired position due to various causes such as variations during manufacturing, and may come into direct contact with each other without passing through the separator 3. By using the sealing material 221 having electrical insulation, even when the first electrode 2 and the second electrode 4 are in direct contact with each other due to such a misalignment, the first electrode 2 and the second electrode 4 Short circuit can be suppressed.

As shown in FIGS. 1 and 2, the separator 3 is laminated on the first electrode 2. The separator 3 is composed of a solid electrolyte having carrier ion conductivity and electrical insulation. The solid electrolyte constituting the separator 3 may be the same type of solid electrolyte as the porous body 23 of the first electrode 2, or may be a different solid electrolyte. Specifically, the separator 3 of this embodiment is composed of the same garnet-type solid electrolyte as the first electrode 2.

The second electrode 4 is laminated on the surface of the separator 3 opposite to the surface on which the first electrode 2 is provided. The second electrode 4 has a polarity different from that of the first electrode 2. That is, when the first electrode 2 is configured as a positive electrode, the second electrode 4 is configured as a negative electrode. When the first electrode 2 is configured as a negative electrode, the second electrode 4 is configured as a positive electrode.

The configuration of the second electrode 4 is not particularly limited. For example, the second electrode 4 may be composed of only an active material different from the active material 211 of the first electrode 2, or the active material may be contained in the pores of the porous body as in the first electrode 2. It may be a retained configuration.

The active material of the second electrode 4 can be appropriately selected according to the carrier ions and the polarities of the second electrode 4, similarly to the first electrode 2. For example, the second electrode 4 of this embodiment is a lithium plate made of metallic lithium as an active material.

Next, a method of manufacturing the secondary battery 1 of this embodiment will be described. The method for producing the secondary battery 1 of the present embodiment is a stacking method including a porous body 23 made of a solid electrolyte having carrier ion conductivity and having pores 231 and a separator 3 laminated on the porous body 23. At least a part of the pores 231 existing in the peripheral portion of the porous body 23 in the laminating step of producing the body 10 and in the plan view from the laminating direction of the laminated body 10 is filled with the sealing material 221 to form the sealing portion. The sealing step of forming 22 and the active material 211 or a precursor thereof are filled in the pores 231 so as to move from the outside of the porous body 23 toward the sealing portion 22 to form the reaction portion 21. It has an active material filling step.

In the laminating step, the specific method for producing the laminated body 10 can take various aspects. In one aspect of the laminating step, the laminated body 10 can be formed by superimposing the green sheet of the porous body 23 and the green sheet of the separator 3 and then firing these green sheets. The green sheet of the porous body 23 can be produced, for example, by molding a mixture containing a powder of a solid electrolyte, a binder and a pore-forming material into a sheet shape. As the pore-forming material, for example, acrylic resin powder or the like can be used. Further, the green sheet of the separator 3 can be produced by molding a mixture containing a powder of a solid electrolyte and a binder into a sheet shape.

Further, in another aspect of the laminating step, the green compact to be the porous body 23 and the green compact to be the separator 3 are superposed, and then these green compacts are fired to form the laminated body 10. Can be formed. The green compact to be the porous body 23 can be produced, for example, by compact molding a mixed powder containing a solid electrolyte powder and a pore-forming material. Further, the green compact to be the separator 3 can be produced by compact molding a powder of a solid electrolyte.

In the sealing step, the method of filling the pores 231 with the sealing material 221 is not particularly limited, and an appropriate method can be adopted depending on the type of the sealing material 221. For example, when a substance having a relatively high melting point such as silica glass is used as the sealing material 221, a paste or sheet obtained by mixing silica glass powder and a binder is placed at a desired position on the porous body 23. After that, the pores 231 can be filled with the sealing material 221 by heating the laminate 10 to melt the sealing material 221. When a substance having a relatively low melting point such as a thermoplastic is used as the sealing material 221, the sealing material 221 in a molten state is injected into the pores 231 and solidified in the pores 231. The pores 231 can be closed.

In the active material filling step, the active material 211 or a precursor thereof is filled in the pores 231 so as to move from the outside of the porous body 23 toward the sealing portion 22. For example, when the sealing portion 22 is provided along the long side 232 of the porous body 23 having a rectangular shape as in the present embodiment, as shown in FIG. 3, the active material 211 or a precursor thereof is provided. May be injected from three sides 233, 234, 235 having no sealing portion 22 at the edge of the porous body 23. In this case, the active material 211 or the like injected from each side 233, 234, 235 of the porous body 23 first moves toward the center in the plan view seen from the stacking direction of the laminated body 10 (FIG. 3, arrow). 212). Then, the active material 211 and the like merged at the central portion of the porous body 23 finally move toward the sealing portion 22 (FIG. 3, arrow 213). At this time, the pores 231 existing in the sealing portion 22 are already closed by the sealing material 221. Therefore, the active material 211 or its precursor that has reached the sealing portion 22 is dammed by the sealing portion 22.

When the active material 211 is filled in the pores 231 in the active material filling step, the filling may be performed until the active material 211 reaches the sealing portion 22. As a result, the reaction unit 21 can be formed. Further, when the precursor of the active material 211 is filled in the pores 231 in the active material filling step, the precursor is reacted by performing a treatment such as heating after the precursor reaches the sealing portion 22. Just do it. As a result, the precursor in the pores 231 can be used as the active material 211 to form the reaction unit 21.

According to this embodiment, it is possible to provide a secondary battery 1 capable of suppressing leakage of the active material 211 from the inside of the first electrode 2 to the outside, and a method for manufacturing the secondary battery 1.

(Embodiment 2)
In this embodiment, another aspect of the arrangement of the sealing portion 22 is shown. In addition, among the symbols used in the present and subsequent forms, the same codes as those used in the existing forms represent the same components and the like as those in the existing forms unless otherwise specified.

The arrangement of the sealing portion 22 is not limited to the embodiment of the first embodiment, and may take various embodiments. For example, even if the sealing portion 22 is provided along two adjacent sides 232 and 233 of the edge of the porous body 23 as in the first electrode 202 of the secondary battery 102 shown in FIG. Alternatively, like the first electrode 203 of the secondary battery 103 shown in FIG. 5, along two sides, one side 232 of the edge of the porous body 23 and the side 234 facing this side. It may be provided. Further, even if the sealing portion 22 is provided along three sides 232, 233, and 234 of the edge of the porous body 23 as in the first electrode 204 of the secondary battery 104 shown in FIG. Good. In producing these secondary batteries 102, 103, 104, in the active material filling step, as in the first embodiment, the active material 211 or a precursor thereof is sealed at the edge of the porous body 23. By injecting from the side that does not have, the leakage of the active material 211 or the like can be suppressed.

Further, the sealing portion 22 may be provided over the entire circumference of the reaction portion 21 as in the first electrode 205 of the secondary battery 105 shown in FIG. 7. In this case, in the active material filling step, the active material 211 or its precursor may be injected from the central portion of the laminated body 10 in a plan view from the stacking direction, that is, the portion inside the reaction portion 21.

When the reaction portion 21 is surrounded by the sealing portion 22 as in the first electrode 205 shown in FIG. 7, it is preferable that the pore 231 of the sealing portion 22 is closed by the electrically insulating sealing material 221. .. In this case, even if the first electrode 205 and the second electrode 4 are displaced in any direction, the short circuit between the first electrode 205 and the second electrode 4 can be suppressed.

Further, when the first electrode is configured as a negative electrode, it is preferable to arrange the sealing portion 22 over the entire circumference of the reaction portion 21 as shown in FIG. In the first electrode configured as the negative electrode, the carrier ions are reduced during charging, so that metal is deposited in the pores of the reaction portion. In this case, by arranging the sealing portion 22 so as to surround the reaction portion 21, the growth of dendrites from the sealing portion 22 toward the second electrode can be suppressed more effectively. As a result, for example, a short circuit between the first electrode and the second electrode at the time of overcharging can be suppressed more effectively.

The secondary batteries 102 to 105 of this embodiment have the same configuration as that of the first embodiment except for the arrangement of the sealing portion 22. The secondary batteries 102 to 105 of the present embodiment can exhibit the same effects as those of the first embodiment, except for the effect of arranging the sealing portion 22.

(Embodiment 3)
In this embodiment, another aspect of the second electrode is shown. In the secondary battery 106 of this embodiment, the reaction portion 21 of the first electrode 205 is referred to as the first reaction portion 21, the active material 211 is referred to as the first active material 211, and the sealing portion 22 is referred to as the first sealing portion 22 and sealed. The pore material 221 is referred to as a first sealing material 221 and the porous body 23 is referred to as a first porous body 23. Although not shown in the figure, in the first electrode 205 of the present embodiment, the first sealing portion 22 is arranged over the entire circumference of the first reaction portion 21, and the first active material 211 is doped with lithium. It has the same configuration as that of the first embodiment except that it is sulfur. Further, the separator 3 of the present embodiment has the same configuration as that of the first embodiment.

As shown in FIG. 8, the second electrode 402 of the present embodiment is arranged at least around the second reaction unit 41 and the second reaction unit 41 in a plan view seen from the stacking direction of the single cell 11. It has a second sealing portion 42 and. As shown in FIG. 9, the second reaction unit 41 is held in the pores 431 of the second porous body 43, which is made of a solid electrolyte having carrier ion conductivity and has pores 431. It has the second active material 411 and the like. The second sealing portion 42 has a second porous body 43 and a second sealing material 421 filled in the pores 431 of the second porous body 43.

Specifically, the second electrode 402 of this embodiment is a negative electrode. Further, as shown in FIG. 8, the second electrode 402 has a rectangular plate shape formed by the second porous body 43.

As shown in FIG. 9, the second reaction portion 41 of the second electrode 402 has a second porous body 43 and a second active material 411 held in the pores 431 of the second porous body 43. doing. In the pores 431 of the second reaction unit 41, in addition to the second active material 411, a conductive auxiliary agent and another solid electrolyte different from the solid electrolyte constituting the second porous body 43 are held. May be good.

Like the first porous body 23, the second porous body 43 is composed of a solid electrolyte having carrier ion conductivity and electrical insulation. The solid electrolyte constituting the second porous body 43 may be the same as or different from the first porous body 23. Specifically, the second porous body 43 of the present embodiment is composed of a garnet-type solid electrolyte.

The second porous body 43 has pores 431 for holding the second active material 411 and the second sealing material 421. The pores 431 of the second porous body 43 may have a continuous pore structure. The porosity of the second porous body 43 can be, for example, 20 to 80%. The porosity of the second porous body 43 is a three-dimensional reconstruction obtained by the FIB / SEM (that is, focused ion beam / scanning electron microscope) tomography method, similarly to the porosity of the first porous body 23. It is a value calculated based on the image.

Although not shown in the figure, when the second active material 411 in the second electrode 402 configured as the negative electrode is a metal as in the present embodiment, the inner surface of the second porous body 43, that is, the second active material. It is preferable that a coating layer made of a metal or a metal oxide is formed on the surface in contact with the 411. In this case, the contact area between the second active material 411 and the porous body 23 can be made wider. As a result, the transfer of carrier ions between the second active material 411 and the second electrode 4 can be further promoted, and charging / discharging can be performed at a higher rate.

Examples of the metal that can be used for the coating layer include gold and aluminum. Further, examples of the metal oxide that can be used for the coating layer include zinc oxide (ZnO) and aluminum oxide (Al ₂ O ₃ ). The coating layer can be formed by, for example, a chemical vapor deposition method, an atomic layer deposition method, a sol-gel method, or the like.

Similar to the first active material 211, the second active material 411 can be appropriately selected according to the polarities of the carrier ions and the second electrode 402. Specifically, the second active material 411 of this embodiment is metallic lithium.

As shown in FIG. 8, the second sealing portion 42 is connected to the edge of the second reaction portion 41 in a plan view seen from the stacking direction of the single cell 11. Like the first sealing portion 22, the second sealing portion 42 may be arranged so as to surround the second reaction portion 41 in a plan view seen from the stacking direction of the single cell 11, or the second reaction portion 42 may be arranged. It may be arranged in a part around the portion 41. Specifically, the second sealing portion 42 of the present embodiment is provided over the entire circumference of the second reaction portion 41 in a plan view viewed from the stacking direction of the single cells 11.

As shown in FIGS. 8 and 9, the second porous body 43 of the second sealing portion 42 is integrally formed with the second porous body 43 of the second reaction portion 41. That is, of the second electrode 402, the portion in which the second active material 411 is held in the pores 431 of the second porous body 43 becomes the second reaction portion 41, and the second pore-sealing material 421 is contained in the pores 431. The portion filled with is the second sealing portion 42.

In the second sealing portion 42, the second sealing material 421 may be filled in all of the pores 431 of the second porous body 43, or a part of the pores 431 may be filled with the second sealing material 421. May be filled. From the viewpoint of more effectively suppressing the entry of the second active material 411 into the second sealing portion 42, the porosity of the second sealing portion 42 is preferably 10% or less, preferably 5% or less. It is more preferable to do so.

The porosity of the second sealing portion 42 is a three-dimensional reconstruction obtained by the FIB / SEM (that is, focused ion beam / scanning electron microscope) tomography method, similarly to the porosity of the first sealing portion 22. It is a value calculated based on the image.

The second sealing material 421 may be made of any substance as long as it can be filled in the pores 431 and the pores 431 can be closed, similarly to the first sealing material 221. Further, the second sealing material 421 may be composed of the same substance as the first sealing material 221 or may be composed of a substance different from the first sealing material 221.

Further, the second sealing material 421 is preferably composed of a substance that can maintain its shape when heated to the melting point of the second active material 411. In this case, in the process of manufacturing the secondary battery 106, when the second active material 411 in the molten state is filled in the pores 431 of the second porous body 43, the second active material 421 is used for the second active material. The substance 411 can be reliably dammed. As a result, the leakage of the second active material 411 can be suppressed more reliably. The second sealing material 421 of the present embodiment is specifically silica glass.

Further, the second sealing material 421 preferably has an electrical insulating property. In this case, it is possible to suppress a short circuit between the first electrode 205 and the second electrode 402 due to misalignment, as in the case where the first sealing material 221 has electrical insulation.

The first electrode 205 in the secondary battery 106 of the present embodiment is configured as a positive electrode having a first active material 211 made of sulfur, and the second electrode 402 is a negative electrode having a second active material 411 made of metallic lithium. It is configured. As described above, when the first electrode 205 is configured as a positive electrode and the second electrode 402 is configured as a negative electrode, the amount of carriers that can be held by the second electrode 402 is the amount of carriers that can be held by the first electrode 205. Preferably more than.

Specifically, the amount of carriers that can be held in each of the electrodes 205 and 402 described above is the volume of the portion of the pores 231 and 431 facing the substance having carrier ion conductivity. It can be calculated by multiplying the theoretical capacity of 411. For example, carriers can enter and exit the portions of the pores 231 and 431 facing the porous bodies 23 and 43 via the porous bodies 23 and 43. Further, when the sealing materials 221 and 421 are substances having carrier ion conductivity, carriers can enter and exit the portions of the pores 231 and 431 facing the sealing materials 221 and 421.

On the other hand, among the pores 231 and 431, in the portion surrounded by the sealing materials 221 and 421 made of, for example, a substance having carrier ion conductivity, the movement of carrier ions is blocked by the sealing materials 221 and 421. Carriers cannot enter or leave.

Therefore, when the electrodes 205 and 402 are completely filled with carriers, the portions of the pores 231 and 431 facing the substance having carrier ion conductivity are filled with the carriers. Therefore, the values obtained by multiplying the volume of the portions of the pores 231 and 431 facing the substance having carrier ion conductivity by the theoretical volumes of the active materials 211 and 411 can be held in the electrodes 205 and 402. The amount of carrier can be.

More specifically, the volume of the portion facing the substance having carrier ion conductivity can be calculated by the following method. That is, first, the pore volume of the reaction portions 21 and 41 when it is assumed that the active materials 211, 411 and the like do not exist in the pores 231 and 431, that is, the volume of the space existing in the reaction portions 21 and 41. , The total volume of the active materials 211 and 411 existing in the reaction units 21 and 41 is calculated. Specifically, the pore volume of each of the reaction parts 21 and 41 is calculated by multiplying the porosity of the porous bodies 23 and 43 in the reaction parts 21 and 41 by the apparent volume of the reaction parts 21 and 41. To.

When the sealing materials 221 and 421 are composed of a substance having carrier ion conductivity, the sealing portion 22 when it is assumed that the active materials 211, 411 and the like are not present in the pores 231 and 431. , 42, that is, the total of the volume of the space existing in the sealing portions 22 and 42 and the volume of the active substances 211 and 411 existing in the sealing portions 22 and 42 is calculated. The pore volumes of the sealing portions 22 and 42 are the same as the pore volumes of the reaction portions 21 and 41, the porosity of the porous bodies 23 and 43 in the sealing portions 22 and 42 and the pore volumes of the sealing portions 22 and 42. It is calculated by multiplying the apparent volume of. By summing the pore volumes of the reaction portions 21 and 41 and the pore volumes of the sealing portions 22 and 42 calculated as described above, the volume of the portion facing the substance having carrier ion conductivity can be obtained. Obtainable.

As described above, by making the amount of carriers that can be held in the second electrode 402 larger than the amount of carriers that can be held in the first electrode 205, all carrier ions are transferred from the first electrode 205 to the second electrode 402. Even when the metal is moved, the metal precipitated by the second electrode 402 can be retained in the pores 431. As a result, it is possible to more reliably suppress the metal precipitated at the second electrode 402 from leaking to the outside of the second electrode 402. As a result, for example, a short circuit between the first electrode 205 and the second electrode 402 at the time of overcharging can be more reliably suppressed.

From the viewpoint of more reliably achieving the above-mentioned effects, the value of the ratio V ₂ / V ₁ of the pore volume V ₂ of the second electrode 402 to the pore volume V ₁ of the first electrode 205 is set to the value of the second active material 411. It is preferable that the ratio of the theoretical volume of the first active material to the theoretical volume of 211 is equal to or greater than the theoretical volume of. For example, the first active material 211 of the present embodiment is lithium doped with lithium, and its theoretical capacity is 3344 mAh / cm ³ . The second active material 411 of this embodiment is metallic lithium, and its theoretical capacity is 2061 mAh / cm ³ . Therefore, when the first active material 211 is lithium doped with lithium and the second active material 411 is metallic lithium as in the present embodiment, the second electrode 402 with respect to the pore volume V ₁ of the first electrode 205 The value of the ratio V ₂ / V ₁ of the pore volume V ₂ is preferably 3344/2061 or more, and more preferably 1.7 or more.

The pore volume V ₁ of the first electrode 205 is calculated by summing the pore volume of the first reaction portion 21 and the pore volume of the first sealing portion 22 calculated by the method described above. Can be done. Similarly, the pore volume V ₂ of the second electrode 402 is calculated by summing the pore volume of the second reaction portion 41 and the pore volume of the second sealing portion 42 calculated by the method described above. be able to.

(Experimental Example 1)
In this example, various test specimens were prepared, and the effect of suppressing leakage of the active materials 211 and 411 by the sealing portions 22 and 42 was evaluated. The preparation method, evaluation method, and evaluation result of the test piece will be described below.

・ Specimen T1
The test body T1 is a secondary battery in which the first electrode 205 is a positive electrode and the second electrode 4 is a negative electrode. The first electrode 205 of the test body T1 has a first reaction portion 21 and a first sealing portion 22 arranged over the entire circumference of the first reaction portion 21. The first reaction unit 21 has a first porous body 23 made of LLZ as a solid electrolyte and sulfur (S) as a first active material 211. The first sealing portion 22 has a first porous body 23 and silica glass as a first sealing material 221. Further, the separator 3 of the test body T1 is composed of LLZ, and the second electrode 4 is a metallic lithium (Li) plate.

In preparing the test body T1, first, a mixture for a separator containing LLZ powder and a binder was prepared. This separator mixture was molded into a sheet using an applicator to prepare a green sheet for the separator 3. Separately, a mixture for electrodes containing LLZ powder, binder and pore-forming material was prepared. This electrode mixture was molded into a sheet using an applicator to prepare a green sheet for the first electrode 205. The thickness of the green sheet of the separator 3 and the green sheet of the first electrode 205 were both set to 300 μm.

The green sheet of the separator 3 and the green sheet of the first electrode 205 formed in this way were cut to a desired size, and both were overlapped. Next, the green sheet of the separator 3 and the green sheet of the first electrode 205 are brought into close contact with each other by a warm isotropic press, and then fired in an air atmosphere to form a laminate 10 of the separator 3 and the first porous body 23. Obtained. The porosity of the first porous body 23 after firing, that is, the porosity of the first active material 211 and the first sealing material 221 in a state where the pores 231 were not filled was 50%.

Next, using a dispenser, a paste containing silica glass powder was applied to the entire outer circumference of the first porous body 23. Then, by heating the laminated body 10 to melt the silica glass powder, the silica glass as the first sealing material 221 was filled in the pores 231 existing on the outer periphery of the first porous body 23. As described above, the first sealing portion 22 was formed on the entire outer circumference of the first porous body 23.

After forming the first sealing portion 22, a green sheet containing sulfur was superposed on the first porous body 23. Sulfur was melted by heating this green sheet to 150 ° C., and the pores 231 of the first porous body 23 were filled with sulfur as the first active material 211. As described above, the first reaction portion 21 was formed in the portion surrounded by the first sealing portion 22.

Next, a gold thin film was formed on the surface of the separator 3 by sputtering. A second electrode 4 made of a metallic lithium plate was placed on this thin film to obtain a test piece T1.

・ Specimen T2
The test body T2 has the same configuration as the test body T1 except that it does not have the first sealing portion 22. The method for producing the test body T2 is the same as that of the test body T1 except that the work of forming the first sealing portion 22 is not performed.

・ Specimen T3
The test body T3 has the same structure as the test body T1 except that lithium cobalt oxide (LCO) is used as the first active material 211. In the method of preparing the test body T3, in the work of filling the first active material 211, a precursor solution of lithium cobalt oxide is injected into the pores 231 and then the precursor solution is calcined into the pores of lithium cobalt oxide. It is the same as the test piece T1 except that the test piece T1 is formed.

・ Specimen T4
The test body T4 has the same configuration as the test body T3 except that it does not have the first sealing portion 22. The method for producing the test body T4 is the same as that of the test body T3 except that the work of forming the first sealing portion 22 is not performed.

・ Specimen T5
In the test body T5, low density polyethylene was tried to be used as the first sealing material 221. In the preparation of the test body T5, after the laminate 10 of the separator 3 and the first porous body 23 is prepared by the same method as the test body T1, the inside of the pores 231 existing on the outer periphery of the first porous body 23 Was filled with molten low density polyethylene. Then, the operation of filling the pores 231 with sulfur as the first active material 211 was performed by the same method as that of the test piece T1.

However, the melting point of the low-density polyethylene used in the test piece T5 is about 90 ° C., which is lower than the melting point of sulfur, which is about 150 ° C. Therefore, the low-density polyethylene was melted in the process of melting the sulfur, and the low-density polyethylene was pushed out of the first porous body 23 by the sulfur. Further, as a result of the absence of low-density polyethylene on the outer periphery of the first porous body 23, sulfur as the first active material 211 leaked to the outside of the first porous body 23.

・ Specimen T6
The test body T6 is a single cell 11 in which the first electrode 205 is a positive electrode and the second electrode 402 is a negative electrode. The first electrode 205 and the separator 3 of the test body T6 have the same configuration as the test body T1. The second electrode 402 of the test body T6 has a second reaction portion 41 and a second sealing portion 42 arranged over the entire circumference of the second reaction portion 41. The second reaction unit 41 has a second porous body 43 made of LLZ as a solid electrolyte and metallic lithium as a second active material 411. The second sealing portion 42 has a second porous body 43 and silica glass as a second sealing material 421.

In preparing the test body T6, first, a mixture for a separator containing LLZ powder and a binder was prepared. This separator mixture was molded into a sheet using an applicator to prepare a green sheet for the separator 3. Separately, a mixture for electrodes containing LLZ powder, binder and pore-forming material was prepared. This electrode mixture was molded into a sheet using an applicator to prepare a green sheet for the first electrode 205 and the second electrode 402. The thickness of the green sheet of the first electrode 205, the green sheet of the separator 3, and the green sheet of the second electrode 402 were all set to 300 μm.

After cutting these three green sheets to a desired size, the green sheet of the first electrode 205, the green sheet of the separator 3, and the green sheet of the second electrode 402 were superposed in this order. Next, the three green sheets were brought into close contact with each other by a warm isotropic press, and then fired in an air atmosphere to form a three-layer structure in which the first porous body 23, the separator 3, and the second porous body 43 were sequentially laminated. A laminated body 10 having a structure was obtained. The porosity of the first porous body 23 and the porosity of the second porous body 43 after firing were both 50%.

Next, using a dispenser, a paste containing silica glass powder was applied to the entire outer circumference of the first porous body 23 and the entire outer circumference of the second porous body 43. Then, by heating the laminated body 10 to melt the silica glass powder, the silica glass was filled in the pores 231 and 431 existing on the outer periphery of these porous bodies 23 and 43. As described above, the first sealing portion 22 was formed on the outer periphery of the first porous body 23, and the second sealing portion 42 was formed on the outer periphery of the second porous body 43.

After forming the first sealing portion 22 and the second sealing portion 42, a metallic lithium foil was superposed on the second porous body 43. The metallic lithium foil was heated to 200 ° C. in an inert gas atmosphere to melt the metallic lithium, and the pores 431 of the second porous body 43 were filled with metallic lithium as the second active material 411. As described above, the second reaction portion 41 was formed in the portion surrounded by the second sealing portion 42.

Then, a green sheet containing sulfur was superposed on the first porous body 23. By heating this green sheet to a temperature of 150 ° C. or higher and lower than 200 ° C. in an inert gas atmosphere, the first one is formed in the pores 231 of the first porous body 23 while retaining the metallic lithium of the second reaction unit 41. It was filled with sulfur as the active material 211. As described above, the first reaction portion 21 was formed in the portion surrounded by the first sealing portion 22, and the test body T6 was obtained.

・ Specimen T7
The test body T7 has the same configuration as the test body T6 except that polyphenylene sulfide (PPS) is used as the first sealing material 221 and the second sealing material 421. The method for producing the test body T7 is the same as that of the test body T6 except that the molten PPS is filled in the pores 231 and 431 in the work of filling the first sealing material 221 and the second sealing material 421. ..

・ Specimen T8
The test body T8 has the same configuration as the test body T6 except that vanadium (V) -based low melting point glass is used as the first sealing material 221 and the second sealing material 421. The test body T8 is produced in the test body T6 except that the pores 231 and 431 are filled with molten vanadium-based low melting point glass in the work of filling the first sealing material 221 and the second sealing material 421. Is similar to.

・ Specimen T9
The test body T9 has the same configuration as the test body T6 except that bismuth (Bi) -based low melting point glass is used as the first sealing material 221 and the second sealing material 421. The test body T9 is prepared in the test body T6 except that the pores 231 and 431 are filled with molten bismuth-based low melting point glass in the work of filling the first sealing material 221 and the second sealing material 421. Is similar to.

・ Specimen T10
The test body T10 has the same configuration as the test body T6 except that lead (Pb) -based low melting point glass is used as the first sealing material 221 and the second sealing material 421. The method for producing the test body T10 is the test body T6 except that the pores 231 and 431 are filled with molten lead-based low melting point glass in the work of filling the first sealing material 221 and the second sealing material 421. Is similar to.

・ Specimen T11
In the test body T11, polypropylene (PP) was tried to be used as the first sealing material 221 and the second sealing material 421. In the preparation of the test body T11, after preparing the laminated body 10 having the first porous body 23, the separator 3 and the second porous body 43 by the same method as the test body T6, the first porous body 23 The pores 231 and 431 existing on the outer circumference and the outer circumference of the second porous body 43 were filled with molten polypropylene. Then, the work of filling the pores 431 with metallic lithium as the second active material 411 was performed by the same method as that of the test piece T1.

However, the melting point of polypropylene used in the test piece T11 is about 150 ° C., which is lower than the melting point of metallic lithium, which is about 200 ° C. Therefore, polypropylene was melted in the process of melting the metallic lithium, and the polypropylene was pushed out of the second porous body 43 by the metallic lithium. Further, as a result of the absence of polypropylene on the outer periphery of the second porous body 43, metallic lithium as the second active material 411 leaked to the outside of the second porous body 43.

In this example, the leak suppressing effect of the active materials 211 and 411 by the sealing materials 221, 421 was evaluated based on the charge / discharge characteristics. Specifically, a power supply device was connected between the first electrode 205 and the second electrodes 4, 402 of each test piece. Then, the charging rate was set to 0.1C, charging was performed until the voltage of the test piece reached 2.6V, and then the discharge rate was set to 0.1C, and discharging was performed until the voltage of the test piece reached 1.0V. .. In the "Charge / Discharge Test (0.1C)" column of Tables 1 and 2, the symbol "A" is described when charging / discharging is possible, and the symbol "B" is described when charging / discharging is not possible. ..

In the evaluation of the action and effect of the sealing materials 221 and 421, the case of the symbol "A" in which charging / discharging was possible at a charging / discharging rate of 0.1C was judged to be acceptable because no short circuit occurred, and charging / discharging was performed. In the case of the symbol "B", which was impossible, it was determined that the test was rejected because the first electrode 205 and the second electrode 402 were short-circuited due to leakage of the active materials 211 and 411.

In the test bodies T1, the test bodies T3, and the test bodies T6 to T10, the pores 231 and 431 existing around the porous bodies 23 and 43 were closed by the sealing materials 221, 421. Therefore, in the process of preparing the test body, the active materials 211 and 411 did not leak from the inside to the outside of the porous bodies 23 and 43. As shown in Tables 1 and 2, these test specimens were able to be charged and discharged at a charge / discharge rate of 0.1C. From these results, by arranging the sealing portions 22 and 42 around the reaction portions 21 and 41 as in the test specimens T1, the test specimens T3 and the test specimens T6 to T10, the active materials 211 and 411 leak out. It can be understood that the short circuit between the 1-electrode 205 and the 2nd electrodes 4, 402 can be suppressed.

On the other hand, in the test body T2 and the test body T4, the pores 231 of the first porous body 23 were open to the outer peripheral edge in the plan view from the stacking direction of the single cell 11. Therefore, in the process of producing the test body, the active material 211 leaked from the inside to the outside of the first porous body 23. As shown in Tables 1 and 2, these test specimens could not be charged / discharged at a charge / discharge rate of 0.1C.

Further, in the test body T5 and the test body T10, as described above, polyethylene and polypropylene were melted during the filling operation of the active materials 211 and 411, so that the sealing portions 22 and 42 were formed around the porous bodies 23 and 43. Could not be formed. Therefore, in these test bodies, the active materials 211 and 411 leak from the inside to the outside of the porous bodies 23 and 43 in the process of preparing the test bodies, and charging / discharging may be performed at a charging / discharging rate of 0.1C. could not.

(Experimental Example 2)
In this example, a test piece was prepared using any of the electrically insulating sealing materials 221 and 421 or the electrically conductive sealing materials 221 and 421, and the short-circuit suppressing effect in the manufacturing process was evaluated. In this example, in addition to using the test body T6 in Experimental Example 1, two new test bodies were prepared. The preparation method, evaluation method, and evaluation result of the test piece will be described below.
・ Specimen T12
The test body T12 has the same configuration as the test body T6 except that LLZ is used as the first sealing material 221 and the second sealing material 421. The method for producing the test body T12 is as follows. First, a separator mixture containing LLZ powder and a binder and an electrode mixture containing LLZ powder, a binder and a pore-forming material were prepared. Next, the mixture for electrodes was molded into a sheet using an applicator to prepare a green sheet for the first reaction section 21. Next, a separator mixture was formed into a sheet around the green sheet of the first reaction section 21 using an applicator, and the green sheet of the first sealing section 22 was placed.

On the green sheet of the first electrode 205 obtained as described above, the separator mixture was formed into a sheet by using an applicator and superposed, and the green sheet of the separator 3 was laminated. Further, on the green sheet of the separator 3, the second electrode 402 provided with the green sheet of the second reaction section 41 and the green sheet of the second sealing portion 42 by the same procedure as the green sheet of the first electrode 205. The green sheets were laminated. The thickness of the green sheet of the first electrode 205, the green sheet of the separator 3, and the green sheet of the second electrode 402 were all set to 300 μm.

Next, these three layers of green sheets are brought into close contact with each other by a warm isotropic press, and then fired in an air atmosphere, so that the first porous body 23, the separator 3, and the second porous body 43 are sequentially laminated. , A three-layered laminated body 10 in which the first sealing portion 22 and the second sealing portion 42 were provided around the first porous body 23 and the second porous body 43, respectively, was obtained.

Then, the pores 431 of the second porous body 43 were filled with metallic lithium by the same method as that of the test body T6, and then the pores 231 of the first porous body 23 were filled with sulfur. From the above, a test body T12 was obtained.

・ Specimen T13
The test body T13 has the same configuration as the test body T6 except that a low melting point copper alloy is used as the first sealing material 221 and the second sealing material 421. In preparing the test body T13, in the work of filling the first sealing material 221 and the second sealing material 421, the paste of the low melting point copper alloy was filled in the pores 231 and 431, and then the paste was fired. The low melting point copper alloy was melted. As described above, the test body T13 was prepared by the same method as the test body T6 except that the pores 231 and 431 were closed with the low melting point copper alloy.

In this example, the short-circuit suppressing effect in the manufacturing process was evaluated based on the occurrence rate of short-circuits. Specifically, five test pieces were prepared and a charge / discharge test was performed by the same method as in Experimental Example 1. Then, the occurrence rate of short circuits, that is, the ratio of the number of test bodies that could not be charged and discharged at 0.1 C to the number of manufactured test bodies was calculated. The “short circuit occurrence rate” in Table 3 shows the short circuit occurrence rate in each test piece.

As shown in Table 3, in the test body T6 and the test body T12 using the electrically insulating sealing materials 221 and 421, the occurrence of a short circuit could be prevented. On the other hand, since the test body T13 uses the conductive sealing materials 221 and 421, the occurrence rate of short circuit is higher than that of the test body T6 and the test body T12.

(Experimental Example 3)
In this example, the porosity of the sealing portions 22 and 42 was adjusted to various values to prepare a test body, and the leakage suppressing effect of the active materials 211 and 411 was evaluated.

-Test body T14, test body T15
The test body T14 and the test body T15 have the same configuration as the test body T12 except that the porosity of the first sealing portion 22 and the porosity of the second sealing portion 42 are set to the values shown in Table 4. There is. In the method for producing these test specimens, when forming the green sheet of the first sealing material 221 and the second sealing material 421, a mixture containing LLZ powder, a binder and a pore-forming material is used to determine the porosity. It is the same as the test body T12 except that it is adjusted.

The leak suppressing effect of the active materials 211 and 411 in this example was evaluated based on the occurrence rate of short circuits as in Experimental Example 2. The “short circuit occurrence rate” in Table 4 shows the short circuit occurrence rate in each test piece.

According to the results shown in Table 4, by setting the porosity of the sealing portions 22 and 42 to 10% or less, it is possible to more effectively suppress the leakage of the active materials 211 and 411 in the manufacturing process. Can be understood.

(Experimental Example 4)
In this example, the porosity of the sealing portions 22 and 42 and the ratio of the pore volume of the first electrode 205 to the pore volume of the second electrode 402 are changed by changing the thickness and the porosity of the electrodes 205 and 402. Specimens were prepared by adjusting to various values, and the short-circuit suppression effect at the time of overcharging was evaluated. In this example, in addition to using the test body T12 in Experimental Example 2, three new test bodies were prepared. The preparation method, evaluation method, and evaluation result of the test piece will be described below.

・ Specimen T16
In the test body T16, the porosity of the first sealing portion 22 and the porosity of the second sealing portion 42 are set to 5%, and the pore volume V ₁ of the first electrode 205 and the pore volume of the second electrode 402 are set to 5%. except that the value of the ratio V ₂ / V ₁ with V ₂ and to the values shown in Table 5 has the same configuration as the specimen T12. The method for producing the test piece T16 is to adjust the porosity by using a mixture containing LLZ powder, a binder and a pore-forming material when forming a green sheet of the first sealing material 221 and the second sealing material 421. Further, the thickness of the second electrode 402 is 1.7 times the thickness of the first electrode 205, thereby increasing the volume of the pores 431 by 1.7 times, which is the same as that of the test body T12.

・ Specimen T17
Specimen T17 has a pore volume V ₁ of the first electrode 205, the value of the ratio V ₂ / V ₁ of the the pore volume V ₂ of the second electrode 402 except that the values shown in Table 5, the test body It has the same configuration as T12. The method for producing the test body T17 is the same as that of the test body T12, except that the volume of the pore 431 is increased by 1.7 times by increasing the thickness of the second electrode 402 by 1.7 times the thickness of the first electrode 205. Is.

・ Specimen T18
Specimen T18 has a pore volume V ₁ of the first electrode 205, the value of the ratio V ₂ / V ₁ of the the pore volume V ₂ of the second electrode 402 except that the values shown in Table 5, the test body It has the same configuration as T12. The test body T18 was prepared except that the volume of the pores 431 was increased by 1.7 times by increasing the porosity of the second porous body 43 by 1.7 times that of the first porous body 23. It is the same as T12.

In this example, the short-circuit suppression effect at the time of overcharging was evaluated by the following method. First, a power supply device was connected between the first electrode 205 and the second electrodes 4, 402 of each test piece. Then, the charging rate was set to 0.1C, charging was performed until the voltage of the test piece reached 3.2V, and the presence or absence of a short circuit was evaluated. In the "overcharge test" column of Tables 1 and 2, the symbol "A" is described when a short circuit does not occur, and the symbol "B" is described when a short circuit occurs.

According to the results shown in Table 5, the porosity of the sealing portions 22 and 42 was set to 5% or less, and the pore volume V ₂ of the second electrode 402 was set to 1. of the pore volume V ₁ of the first electrode 205. It can be understood that it is possible to more effectively suppress the short circuit between the first electrode 205 and the second electrode 402 at the time of overcharging by setting the value to 7 times or more.

(Experimental Example 5)
In this example, a test piece having a coating layer formed in the pores 231 and 431 was prepared, and the charge / discharge characteristics were evaluated.

・ Specimen T19
The test body T19 has the same structure as the test body T12 except that the inner surface of the second reaction unit 41 is covered with a coating layer made of gold. The method for producing the test body T19 is the same as that for the test body T12, except that a coating layer is formed on the inner surface of the second reaction unit 41 by the ALD method after the laminated body 10 is prepared.

In this example, the effect of improving the charge / discharge rate was evaluated based on the charge / discharge characteristics. Specifically, the charge / discharge test was performed by the same method as in Experimental Example 1 except that the charge / discharge rate was changed to 1C. In the "Charge / Discharge Test (1C)" column of Table 6, the symbol "A" is described when charging / discharging is possible, and the symbol "B" is described when charging / discharging is not possible.

According to the results shown in Table 6, it is understood that charging and discharging at a high rate is possible by providing a coating layer on the inner surface of the reaction unit 41 and bringing the active material 411 made of metal into contact with the coating layer. it can.

The present invention is not limited to the above embodiments and experimental examples, and can be applied to various embodiments without departing from the gist thereof.

1, 102, 103, 104, 105, 106 Secondary battery 11 Single cell 2, 202, 203, 204, 205 First electrode 21 Reaction part 211 Active material 22 Sealing part 221 Sealing material 23 Porous medium 231 Pore 3 Separator 4, 402 2nd electrode

Claims (6)

With the first electrode (2, 202-205),
The separator (3) laminated on the first electrode and
It has a single cell (11) provided with a second electrode (4, 402) laminated on the separator.
The first electrode is
A reaction unit (23) comprising a porous body (23) made of a solid electrolyte having carrier ion conductivity and having pores, and an active material (211) held in the pores (231) of the porous body. 21) and
The porous body and the sealing material (221) filled in the pores of the porous body, which are arranged at least a part around the reaction portion in a plan view seen from the stacking direction of the single cell, A secondary battery (1, 102-106) having a sealing portion (22) and the like. The secondary battery according to claim 1, wherein the sealing material has electrical insulation. The reaction unit of the first electrode is a first reaction unit (21) including a first porous body (23) as the porous body and a first active material (211) as the active material. And
The sealing portion of the first electrode is a first sealing portion (22) including the first porous body and the first sealing material (221) as the sealing material.
The second electrode (402) is
A second porous body (43) composed of a solid electrolyte having carrier ion conductivity and having pores (431), and a second active material (411) held in the pores of the second porous body. The second reaction unit (41) provided with
A second porous body is arranged in at least a part around the second reaction portion in a plan view seen from the stacking direction of the single cell, and the pores of the second porous body and the second porous body are filled. The secondary battery (106) according to claim 1 or 2, further comprising a sealing material (421) and a second sealing portion (42). The third electrode is claimed, wherein the first electrode is configured as a positive electrode, the second electrode is configured as a negative electrode, and the pore volume of the second electrode is larger than the pore volume of the first electrode. The described secondary battery. The secondary battery according to claim 4, wherein the value of the ratio V ₂ / V ₁ of the pore volume V ₂ of the second electrode to the pore volume V ₁ of the first electrode is 1.7 or more. The method for manufacturing a secondary battery according to any one of claims 1 to 5.
A laminating step of producing a laminated body (10) including a porous body (23) made of a solid electrolyte having carrier ion conductivity and having pores, and the separator laminated on the porous body.
A sealing step of filling at least a part of the pores existing in the peripheral edge of the porous body in a plan view from the stacking direction of the laminated body with a sealing material (221) to form the sealing portion. When,
An active material filling step of filling the pores with the active material (211) or a precursor thereof so as to move from the outside of the porous body toward the sealing portion to form the reaction portion. A method for manufacturing a secondary battery.

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