WO2024089967A1

WO2024089967A1 - Manufacturing method for all-solid-state battery

Info

Publication number: WO2024089967A1
Application number: PCT/JP2023/028575
Authority: WO
Inventors: 健児岡本; 英之福井
Original assignee: 日立造船株式会社
Priority date: 2022-10-28
Filing date: 2023-08-04
Publication date: 2024-05-02
Also published as: JP2024064694A

Abstract

This disclosed manufacturing method is for manufacturing an all-solid-state battery including at least one unit cell that includes a positive electrode layer, a negative electrode layer, and a solid electrolyte layer disposed between the positive electrode layer and the negative electrode layer. This manufacturing method includes: a step (i) for disposing, inside an exterior body having an opening, a fluid first resin-containing material for which curing is not complete; and a step (ii) for inserting a laminate (110), including the at least one unit cell, into the exterior body (120) and thereafter completing the curing of the first resin-containing material, thus disposing the cured first resin-containing material (201b) between the exterior body (120) and the laminate (110).

Description

Manufacturing method for all-solid-state batteries

This disclosure relates to a method for manufacturing an all-solid-state battery.

Currently, all-solid-state batteries, which have high safety and energy density, are attracting attention. All-solid-state batteries contain a laminate that includes a positive electrode layer, a solid electrolyte layer, and a negative electrode layer as a power generation element. Various proposals have been made regarding the structure and manufacturing methods of all-solid-state batteries.

Claim 1 of Patent Document 1 (JP 2019-207840 A) describes "an all-solid-state battery including a laminated electrode body having a structural portion in which an electrode mixture layer and a solid electrolyte layer are laminated, and a sealing portion covering at least a laminate end face of the laminated electrode body, wherein the electrode mixture layer contains an active material and a binder resin, the sealing portion contains a sealing resin and insulating particles, and the absolute value of the difference between the solubility parameter of the binder resin contained in the electrode mixture layer and the solubility parameter of the sealing resin contained in the sealing portion is 1.9 (cal/cm ³ ) ^0.5 or less."

Claim 1 of Patent Document 2 (Patent No. 6673249) describes a method for manufacturing a laminated all-solid-state battery, which includes: housing an all-solid-state battery stack having one or more all-solid-state battery elements in which a negative electrode current collector layer having a negative electrode current collector tab, a negative electrode active material layer, a solid electrolyte layer, a positive electrode active material layer, and a positive electrode current collector layer having a positive electrode current collector tab are stacked in this order within an exterior body made of a laminate film; applying pressure to the all-solid-state battery stack housed within the exterior body in the stacking direction from the outside of the exterior body; injecting a filler material into the exterior body while maintaining the pressure; and sealing the exterior body, wherein the pressure applied in the step of applying pressure to the all-solid-state battery stack in the stacking direction is greater than the filler material injection pressure in the step of injecting the filler material.

Patent Document 3 (Patent No. 6772855) states in claim 1 that "an all-solid-state battery includes an all-solid-state battery element having one or more unit cells in which an anode current collector layer, an anode active material layer, a solid electrolyte layer, a cathode active material layer, and a cathode current collector layer are arranged in this order; a metal exterior body having an opening at at least one end and housing the all-solid-state battery element; a resin sealant sealing the opening and contacting the surface of the all-solid-state battery element facing the opening; and an anode current collector layer protrusion and a cathode current collector layer protrusion protruding from the resin sealant to the side opposite the all-solid-state battery element, the resin sealant penetrating at least a part of the gap between the outer periphery of the all-solid-state battery element and the inner periphery of the metal exterior body to form a gap filler, and the resin sealant is a curable resin."

JP 2019-207840 A Japanese Patent No. 6673249 Patent No. 6772855

When a conventional all-solid-state battery is used under reduced pressure, if the pressure inside the case becomes higher than the external pressure, the battery expands and its performance deteriorates. Even if the pressure inside the case is negative, in order to prevent the battery from expanding under reduced pressure, it is necessary to create a high vacuum inside the case or to use a pressurized structure for the case. In this situation, one of the objectives of the present disclosure is to provide a manufacturing method that can easily manufacture an all-solid-state battery that is less likely to expand even under reduced pressure.

One aspect of the present disclosure relates to a first method for producing an all-solid-state battery. The first method for producing an all-solid-state battery includes at least one unit battery including a positive electrode layer, a negative electrode layer, and a solid electrolyte layer disposed between the positive electrode layer and the negative electrode layer, and includes the steps of (i) disposing a first resin-containing material having fluidity and not yet cured in an exterior body having an opening, and (ii) inserting a stack including the at least one unit battery into the exterior body, completing the curing of the first resin-containing material, and disposing the cured first resin-containing material between the exterior body and the stack.

One aspect of the present disclosure relates to a second manufacturing method for an all-solid-state battery. The second manufacturing method is a manufacturing method for an all-solid-state battery including at least one unit battery including a positive electrode layer, a negative electrode layer, and a solid electrolyte layer disposed between the positive electrode layer and the negative electrode layer, and includes a step (I) of disposing a laminate including the at least one unit battery in an exterior body having an opening, and a step (II) of disposing the cured resin-containing material between the exterior body and the laminate by starting the supply of a resin-containing material having fluidity that has not yet been cured from the lower side of the exterior body, filling the resin-containing material into the exterior body, and then completing the curing of the resin-containing material.

According to the manufacturing method of the present disclosure, it is possible to easily manufacture an all-solid-state battery that is less likely to expand even under reduced pressure.
The novel features of the present invention are set forth in the appended claims, but the present invention, both in terms of structure and content, together with other objects and features of the present invention, will be better understood from the following detailed description taken in conjunction with the drawings.

FIG. 1A is a top view diagrammatically illustrating an example of a laminate used in the first embodiment. FIG. 1B is a cross-sectional view taken along line IB-IB in FIG. 1A. FIG. 2A is a cross-sectional view that illustrates a step of the manufacturing method according to the first embodiment. FIG. 2B is a cross-sectional view that typically illustrates a step subsequent to the step illustrated in FIG. 2A. FIG. 3A is a cross-sectional view that illustrates an example of an exterior body used in the manufacturing method of embodiment 1. FIG. 3B is a cross-sectional view that illustrates another example of an exterior body used in the manufacturing method of embodiment 1. FIG. 3C is a cross-sectional view that illustrates an example of deformation of the exterior body in the manufacturing method of embodiment 1. FIG. 4A is a cross-sectional view that illustrates a step of the manufacturing method according to the second embodiment. FIG. 4B is a cross-sectional view that typically illustrates a step subsequent to the step illustrated in FIG. 4A. FIG. 5 is a cross-sectional view illustrating an example of a process of the manufacturing method according to the second embodiment. FIG. 6 is a cross-sectional view illustrating another example of a step of the manufacturing method according to the second embodiment.

Below, examples of embodiments of the present disclosure are described, but the present disclosure is not limited to the examples described below. In the following description, specific numerical values and materials may be exemplified, but other numerical values and other materials may be applied as long as the invention of the present disclosure can be implemented. In this specification, the expression "numerical value A to numerical value B" includes numerical value A and numerical value B and can be read as "numerical value A or more and numerical value B or less." In the following description, when numerical values for specific physical properties or conditions are exemplified as lower and upper limits, any of the exemplified lower limits can be arbitrarily combined with any of the exemplified upper limits, as long as the lower limit is not greater than the upper limit.

The first and second manufacturing methods for the all-solid-state battery are described below. The first and second manufacturing methods may be referred to as "manufacturing method (M1)" and "manufacturing method (M2)" below.

The manufacturing method (M1) and the manufacturing method (M2) are each a method for manufacturing an all-solid-state battery including at least one unit cell including a positive electrode layer, a negative electrode layer, and a solid electrolyte layer disposed between the positive electrode layer and the negative electrode layer. In the manufacturing method (M1) and the manufacturing method (M2), a laminate including at least one unit cell is used. Hereinafter, the laminate may be referred to as a "laminate (S)". Typically, a positive electrode lead tab and a negative electrode lead tab protrude from the laminate (S). An example of the configuration of an all-solid-state battery will be described later. There is no limitation on the method for preparing the laminate (S). The laminate (S) may be formed by the method described later, or a formed laminate (S) may be obtained and used.

(First manufacturing method (manufacturing method (M1)))
In the conventional manufacturing method, the laminate (S) is placed inside the exterior body, and then the sealing resin is injected through an opening of the exterior body to surround the laminate (S). However, since the viscosity of the sealing resin is relatively high, it is difficult to inject the sealing resin so as not to form a gap between the laminate (S) and the exterior body. If a large gap where no sealing resin is placed is formed between the laminate (S) and the exterior body, the battery is likely to expand under reduced pressure.

As described below, in manufacturing method (M1), the first resin-containing material is disposed in advance inside the exterior body, and then the laminate (S) is inserted into the exterior body. Therefore, manufacturing method (M1) can prevent the formation of a large gap between the laminate (S) and the exterior body where no sealing resin is disposed. As a result, an all-solid-state battery that is less likely to expand even under reduced pressure is obtained. Furthermore, in manufacturing method (M1), since it is easy to dispose the first resin-containing material in the exterior body, an all-solid-state battery can be easily manufactured.

The first manufacturing method (manufacturing method (M1)) of an all-solid-state battery includes steps (i) and (ii) in this order. These steps are described below.

(Step (i))
Step (i) is a step of disposing a first resin-containing material having fluidity and not yet cured in an exterior body having an opening. For example, a bottomed rectangular tubular exterior body can be used as the exterior body having an opening. The rectangular tubular part has two main walls (plate-shaped parts) and two side walls connecting the two main walls. One end of the rectangular tubular part is sealed at the bottom, and the other end is open as an opening.

The first resin-containing material is not particularly limited, and may be any material that contains a curable resin and can seal the laminate (S) containing the unit cells. A known sealing resin used for sealing electronic components may be used as the first resin-containing material. The first resin-containing material contains at least a resin. The first resin-containing material may be composed of only a resin, or may be composed of a resin and a material other than a resin. Examples of resins contained in the first resin-containing material include epoxy resin and silicone resin. By using an epoxy resin, the bonding force between the two main walls is strengthened. As a result, the expansion of the exterior body under reduced pressure can be particularly suppressed. Since silicone resin has high viscoelasticity, the use of silicone resin can soften the impact on the laminate (S) and increase the impact resistance of the battery.

The first resin-containing material may include a filler dispersed in the resin. Examples of the filler include inorganic fillers such as alumina particles, silica particles, etc.

The first resin-containing material is placed in the exterior body in a fluid state where it has not yet completely hardened. As long as it has fluidity, the first resin-containing material may have started to harden when it is placed in the exterior body. There are no limitations on the method of placing the first resin-containing material in the exterior body. For example, the first resin-containing material may be dripped from an opening. Alternatively, a nozzle may be inserted into the exterior body and the first resin-containing material may be filled into the exterior body from the nozzle.

The viscosity of the first resin-containing material placed in the exterior body in step (i) may be 70 Pa·s or less, 20 Pa·s or less, 10 Pa·s or less, 5.0 Pa·s or less, or 3.0 Pa·s or less. The lower limit of the viscosity is not particularly limited, but may be 0.1 Pa·s or more, 0.3 Pa·s or more, or 0.5 Pa·s or more. By setting the viscosity to 20 Pa·s or less (for example, 10 Pa·s or less or 5.0 Pa or less), it becomes easier to place the first resin-containing material in the exterior body, and also makes it easier to insert the laminate (S) into the exterior body in step (ii). By using a silicone resin, it becomes easier to obtain a first resin-containing material with a low viscosity. The viscosity of the resin-containing material containing the silicone resin can be measured using a Brookfield type rotational viscometer.

The amount of the first resin-containing material placed in the exterior body in step (i) is an amount that covers a certain portion of the surface of the laminate (S) when the laminate (S) is inserted into the exterior body in step (ii). For example, the amount is preferably an amount that covers 30% or more, 50% or more, 70% or more, or 90% or more of the total surface area of the laminate (S) with the first resin-containing material when the laminate (S) is inserted into the exterior body in step (ii). The amount may be an amount that covers the entire surface of the laminate (S) when the laminate (S) is inserted into the exterior body in step (ii). Alternatively, the amount may be an amount that covers the end face of the laminate (S) other than the end face on the opening side of the exterior body.

(Step (ii))
Step (ii) is a step of inserting the laminate (S) including at least one unit battery into an outer casing, completing the curing of the first resin-containing material, and disposing the cured first resin-containing material between the outer casing and the laminate.

The laminate (S) can be inserted through an opening in the exterior body. After inserting the laminate (S) into the exterior body, the first resin-containing material may be replenished inside the exterior body. It is preferable that the entire laminate (S) is ultimately covered with the first resin-containing material.

The method for completing the hardening of the first resin-containing material is not limited, and is selected according to the type of resin contained in the first resin-containing material. For example, when a resin that hardens with heat is used, the first resin-containing material may be hardened by heating. Also, when a resin that hardens over time is used, the first resin-containing material may be hardened by simply leaving it.

In this way, an all-solid-state battery is obtained that includes the laminate (S) fixed inside the exterior body by the first resin-containing material that has completed curing, and the exterior body.

In step (ii), the laminate (S) may be inserted into the exterior body while the exterior body is pulled outward. This configuration makes it easier to insert the laminate (S) into the exterior body. The method for pulling the exterior body outward is not limited, and the main wall of the exterior body may be adsorbed by vacuum suction or the like and pulled outward. Alternatively, the opening of the exterior body may be widened by a jig or the like. These methods can also be used in manufacturing method (M2).

In step (ii), the laminate (S) may be inserted into the exterior body with the second resin-containing material applied to the surface of the laminate (S). This configuration makes it easier to insert the laminate (S) into the first resin-containing material. The laminate (S) may be inserted into the exterior body with the applied second resin-containing material not yet cured. Alternatively, the laminate (S) may be inserted into the exterior body with the applied second resin-containing material having been cured.

The second resin-containing material may be a material exemplified for the first resin-containing material. The first resin-containing material and the second resin-containing material may contain the same resin. This configuration makes it particularly easy to insert the laminate (S) into the first resin-containing material. This configuration also makes it possible to strengthen the fixation between the resin-containing material in the exterior body and the laminate (S). The first resin-containing material and the second resin-containing material may be composed of the same material. Alternatively, the first resin-containing material and the second resin-containing material may contain the same resin but be composed of different materials overall. Alternatively, the first resin-containing material and the second resin-containing material may be composed of different materials without containing the same resin.

In step (ii), the first resin-containing material may be cured while the exterior body is pressurized from the outside. Specifically, the first resin-containing material may be cured while the two main walls of the exterior body are pressurized toward the inside of the exterior body. With this configuration, the laminate (S) can be sealed while the laminate (S) is pressurized in its stacking direction. By pressurizing the laminate (S) in the stacking direction, the battery performance can be fully exhibited. Furthermore, with this configuration, the battery expansion under reduced pressure can be suppressed.

In step (ii), when the first resin-containing material is cured while the exterior body is pressurized from the outside, the thickness of the central part of the exterior body after step (ii) may be smaller than the thickness of said central part of the exterior body before step (ii) is performed. With this configuration, the laminate (S) can be sealed while being strongly pressurized in the stacking direction. Note that the central part of the exterior body means the central part of one of the main walls of the exterior body when the main wall is viewed in a plan view.

Step (i) and step (ii) may be performed under atmospheric pressure. Alternatively, step (ii) may be performed under reduced pressure. For example, both step (i) and step (ii) may be performed under reduced pressure. By performing step (i) under reduced pressure, it becomes easier to dispose the first resin-containing material inside the exterior body. By performing step (ii) under reduced pressure, it is possible to prevent the formation of voids between the exterior body and the laminate (S). As a result, it is possible to prevent the expansion of the manufactured all-solid-state battery when it is placed under reduced pressure.

(Second manufacturing method (manufacturing method (M2)))
As described below, in the manufacturing method (M2), the supply of the resin-containing material is started from the lower side of the exterior body with the laminate (S) disposed inside the exterior body. This configuration can prevent large voids from being formed inside the exterior body. As a result, an all-solid-state battery that is less likely to expand even under reduced pressure is obtained. Furthermore, in the manufacturing method (M2), since it is easy to fill the first resin-containing material inside the exterior body, the all-solid-state battery can be easily manufactured.

The second manufacturing method (manufacturing method (M2)) of an all-solid-state battery includes step (I) and step (II) in this order. These steps are described below.

(Step (I))
Step (I) is a step of disposing a laminate (S) including at least one unit cell in an exterior body having an opening. The laminate (S) can be inserted into the exterior body through the opening of the exterior body. The exterior body having an opening can be an exterior body exemplified in the description of the manufacturing method (M1).

In step (I), the laminate (S) having a surface coated with a resin-containing material (second resin-containing material) may be placed inside the exterior body. In that case, it becomes easier to fill with the resin-containing material (first resin-containing material) used in step (II). The resin-containing material (first resin-containing material) used in step (II) may be the first resin-containing material exemplified in the description of manufacturing method (M1). The resin-containing material (second resin-containing material) used in step (I) may be the second resin-containing material exemplified in the description of manufacturing method (M1).

(Step (II))
Step (II) is a step of disposing the cured resin-containing material between the exterior body and the laminate by starting the supply of the resin-containing material having fluidity that has not yet been cured from the lower side of the exterior body, filling the resin-containing material into the exterior body, and then completing the curing of the resin-containing material. The method of completing the curing of the resin-containing material is not limited and is selected according to the type of resin contained in the resin-containing material. For example, when a resin that cures with heat is used, the resin-containing material may be cured by heating. Also, when a resin that cures over time is used, the resin-containing material may be cured by simply leaving it.

As described above, the resin-containing material may be the material described as the first resin-containing material in manufacturing method (M1). The fluid state in which curing is not complete has been described in manufacturing method (M1), so a duplicate description will be omitted. The viscosity of the resin-containing material when filled into the exterior body may be within the range described for the viscosity of the first resin-containing material used in step (i) of manufacturing method (M1).

In step (II), the lower side of the exterior body means the side below the center in the vertical direction of the internal space of the exterior body in terms of the position of the exterior body when filling with the resin-containing material. In this case, when the height of the internal space of the exterior body (the length of the internal space of the exterior body in the vertical direction) is H, the supply of the resin-containing material may be started below a height of H/3 from the bottom of the internal space of the exterior body. Alternatively, the supply of the resin-containing material may be started below a height of H/4 from the bottom of the internal space of the exterior body, or below a height of H/5 from the bottom of the internal space of the exterior body.

There is no particular limitation on the method of supplying the resin-containing material from the lower side inside the exterior body. For example, a nozzle (e.g., a tubular nozzle) may be inserted into the exterior body through the opening of the exterior body so that the tip of the nozzle reaches the lower side inside the exterior body, and the resin-containing material may be supplied from the tip of the nozzle. The nozzle is pulled out of the exterior body before the resin-containing material is completely cured. The nozzle may be gradually pulled up toward the opening as the resin-containing material fills the exterior body. At least when the supply of the resin-containing material begins, the resin-containing material is supplied from the lower side inside the exterior body.

Step (II) is usually performed with the exterior body positioned so that the bottom is facing down and the opening is facing up. However, step (II) may also be performed with the exterior body positioned in another direction. For example, step (II) may be performed with one main wall of the exterior body facing down and the other main wall facing up. Alternatively, step (II) may be performed with one side wall of the exterior body facing down and the other side wall facing up. In these cases, the resin-containing material may be filled into the exterior body with part or all of the opening covered.

In step (II), the resin-containing material having fluidity may be filled into the exterior body while the exterior body is pulled outward, and the resin-containing material may then be cured while the exterior body is pressurized from the outside. With this configuration, the laminate (S) can be sealed while the laminate (S) is pressurized in the stacking direction. By pressurizing the laminate (S) in the stacking direction, the battery performance can be fully exhibited. Furthermore, with this configuration, the battery expansion under reduced pressure can be suppressed.

Step (I) and step (II) may be performed under atmospheric pressure. Alternatively, step (II) may be performed under reduced pressure. By performing step (II) under reduced pressure, it becomes easier to fill the resin-containing material into the exterior body. In addition, by performing step (II) under reduced pressure, it is possible to prevent the formation of voids between the exterior body and the laminate (S). As a result, it is possible to prevent the battery from expanding when the manufactured all-solid-state battery is placed under reduced pressure.

In manufacturing methods (M1) and (M2), the exterior body may be made of metal. Examples of metals that can be used for the exterior body will be described later.

In the manufacturing methods (M1) and (M2), the exterior body may be an exterior body that pressurizes the laminate (S) in the stacking direction. One example of such an exterior body is an exterior body in which two main walls are curved so as to be convex toward the inside when nothing is contained. By using such main walls, the laminate (S) can be pressurized in the stacking direction. When an exterior body having such main walls is used, the laminate (S) is inserted into the exterior body with the exterior body (at least the main walls) pulled outward. In the manufacturing methods (M1) and (M2), resin is filled between the exterior body and the laminate (S). Therefore, the pressure force from the exterior body is easily transmitted uniformly to the laminate (S).

When using two main walls that are curved convexly inward, the shape and size of the exterior body are selected so that when the laminate and resin-containing material are housed, the main walls are flatter than before they are housed. With this configuration, the laminate (S) can be pressurized in the stacking direction by the main walls.

In another aspect, the present disclosure provides a third manufacturing method (manufacturing method (M3)) for an all-solid-state battery. The third manufacturing method is a method for manufacturing an all-solid-state battery including at least one unit battery including a positive electrode layer, a negative electrode layer, and a solid electrolyte layer disposed between the positive electrode layer and the negative electrode layer. The third manufacturing method includes a step (Ia) of disposing a laminate including the at least one unit battery in an exterior body having an opening, and a step (IIa) of disposing the cured resin-containing material between the exterior body and the laminate by starting the supply of a resin-containing material having fluidity that has not yet been cured from a lower side of a resin-filled region in the exterior body, filling the resin-containing material into the resin-filled region, and then completing the curing of the resin-containing material.

Step (Ia) is the same as step (I) of manufacturing method (M2) except that the internal space of the exterior body may be divided into upper and lower parts, so a duplicated explanation will be omitted. In step (Ia), if a cylindrical body without a bottom (e.g., a rectangular cylindrical body) is used as the exterior body, a partition can be used to divide the internal space of the exterior body. The partition is formed around the laminate. In manufacturing method (M3), as explained in manufacturing method (M2), a rectangular cylindrical body with a bottom may be used as the exterior body.

　Step (IIa) is a step in which the step (II) of manufacturing method (M2) of "starting the supply of resin-containing material having fluidity that has not yet been cured from the lower side of the exterior body, filling the exterior body with the resin-containing material, and then completing the curing of the resin-containing material" is replaced with the step of "starting the supply of resin-containing material having fluidity that has not yet been cured from the lower side of the resin-filled region of the exterior body, filling the resin-containing material into the resin-filled region, and then completing the curing of the resin-containing material." With the exception of the above replacement, the matters described in step (II) can be applied to step (IIa). With the exception of the differences between step (I) and step (Ia) and the differences between step (II) and step (IIa), the matters described in manufacturing method (M2) can be applied to manufacturing method (M3). From one perspective, manufacturing method (M2) can be considered to be included in manufacturing method (M3).

In step (IIa), the resin-filled area means the space filled with the resin-containing material. In step (IIa), the lower side of the resin-filled area means the side below the vertical center of the resin-filled area in the arrangement of the exterior body when filling with the resin-containing material. In this case, when the height of the resin-filled area (length of the resin-filled area in the vertical direction) is Ha, the supply of the resin-filled material may be started from a side lower than a height of Ha/3 from the bottom of the resin-filled area. Alternatively, the supply of the resin-filled material may be started from a side lower than a height of Ha/4 from the bottom of the resin-filled area, or from a side lower than a height of Ha/5 from the bottom of the resin-filled area.

In the manufacturing method (M3), the internal space of the exterior body may be divided into two spaces (a lower space and an upper space) by a partition arranged around the laminate. For example, in the step (Ia), a laminate having a ridge-like portion arranged around the periphery as a partition may be arranged inside the exterior body, thereby dividing the internal space of the exterior body into two spaces. In that case, two resin-filled regions are formed inside the exterior body. In the step (IIa), first, the supply of a resin-containing material having fluidity is started from the lower side of the upper space (one of the resin-filled regions) to fill the space with the resin-containing material, and then the resin-containing material is hardened. Next, the exterior body is turned upside down, and the supply of a resin-containing material having fluidity is started from the lower side of the other space (the other resin-filled region) to fill the space with the resin-containing material, and then the resin-containing material is hardened. In this way, the hardened resin-containing material can be arranged in two spaces (two resin-filled regions).

(Components of all-solid-state batteries)
The all-solid-state battery manufactured by the manufacturing method (M1) and the all-solid-state battery manufactured by the manufacturing method (M2) basically have the same configuration. Examples of components of the all-solid-state battery manufactured by the manufacturing method (M1) and the manufacturing method (M2) are described below. However, the following components are examples, and other components may be used. Note that, although the following mainly describes an example of an all-solid-state lithium ion battery, other all-solid-state batteries may also be used. The all-solid-state battery is not particularly limited, and may be a known all-solid-state battery.

The all-solid-state battery includes a laminate (S). The laminate (S) includes at least one unit cell (power generating element). The laminate (S) may include only one unit cell, or may include multiple unit cells stacked together. The unit cell includes a positive electrode layer, a negative electrode layer, and a solid electrolyte layer disposed between the positive electrode layer and the negative electrode layer. The laminate (S) includes a current collector as necessary. In an all-solid-state battery, it is preferable that the laminate (S) is pressurized in the stacking direction. Pressurizing the laminate (S) enables it to exhibit high performance.

(Exterior body)
As described above, the exterior body can be a metal case, etc. Examples of the metal plate constituting the case include a stainless steel plate, a carbon steel plate, an aluminum alloy plate, etc.

The thickness of the metal plate constituting the exterior body may be selected according to the material, the required pressure resistance, and the material of the metal plate. The thickness of the metal plate constituting the exterior body may be 0.10 mm or more, or 0.15 mm or more, and may be 0.60 mm or less, or 0.50 mm or less.

(Positive electrode layer)
The positive electrode layer includes a positive electrode active material, and may include other components as necessary. Examples of the other components include known components (such as binders and conductive materials) used in the positive electrode layer of all-solid-state batteries. From the viewpoint of increasing the lithium ion conductivity in the positive electrode layer, the positive electrode layer may include a solid electrolyte exhibiting lithium ion conductivity together with the positive electrode active material. Usually, the positive electrode active material is used in the form of particles (powder).

The positive electrode active material may be a material that can be used as a positive electrode active material for a solid-state battery. In the case of a solid-state lithium-ion battery, examples of the positive electrode active material include lithium-containing composite oxides and compounds other than oxides. Examples of lithium-containing composite oxides include lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, and other lithium-containing composite oxides (LiNi _0.8 Co _0.15 Al _0.05 O ₂ , etc.). Examples of compounds other than oxides include olivine compounds (LiMPO ₄ , etc.), sulfur-containing compounds (Li ₂ S, etc.), etc. In the above formula, M represents a transition metal. The positive electrode active material may be used alone or in combination of two or more types.

(Negative electrode layer)
The negative electrode layer includes a negative electrode active material, and may include other components as necessary. Examples of the other components include known components (such as binders and conductive materials) used in the negative electrode layer of all-solid-state batteries. The negative electrode layer may include a negative electrode active material and a solid electrolyte exhibiting lithium ion conductivity. Usually, the negative electrode active material is used in the form of particles (powder).

The negative electrode active material may be a material that can be used as a negative electrode active material for an all-solid-state battery. In the case of an all-solid-state lithium-ion battery, the negative electrode active material may be a specific material (such as a carbonaceous material, a metal or semimetal element or alloy, or a compound) that can reversibly store and release lithium ions. Examples of carbonaceous materials include graphite (natural graphite, artificial graphite, etc.), hard carbon, and amorphous carbon. Examples of metal or semimetal element or alloy include lithium metal or alloy, and simple silicon. Examples of compounds include oxides (such as titanium oxide and silicon oxide), sulfides, nitrides, hydrates, and silicides (such as lithium silicide). The negative electrode active material may be used alone or in combination of two or more types. For example, silicon oxide and a carbonaceous material may be used in combination. As the negative electrode active material, particles containing graphite particles and amorphous carbon covering the graphite particles may be used.

(Solid electrolyte layer)
The solid electrolyte layer is disposed between the positive electrode layer and the negative electrode layer. The solid electrolyte layer includes a solid electrolyte, and may include other components as necessary. Examples of the other components include known components used in the solid electrolyte layer of an all-solid-state battery. The solid electrolyte is usually used in the form of particles (powder).

The solid electrolyte can be any material that can be used as a solid electrolyte in an all-solid-state battery, without any particular restrictions. In the case of an all-solid-state lithium-ion battery, the solid electrolyte can be any material that has lithium ion conductivity. Examples of such solid electrolytes include inorganic solid electrolytes such as sulfides (sulfide-based solid electrolytes) and hydrides (hydride-based solid electrolytes).

Examples of sulfides include Li ₂ S-SiS ₂ , Li ₂ S-P ₂ S ₅ , Li ₂ S-GeS ₂ , Li ₂ S-B ₂ S ₃ , Li ₂ S-Ga ₂ S ₃ , Li ₂ S-Al ₂ S ₃ , Li ₂ S-GeS ₂ -P ₂ S ₅ , Li ₂ S-Al ₂ S ₃ -P ₂ S ₅ , Li ₂ S-P ₂ S ₃ , Li ₂ S-P ₂ S ₃ -P ₂ S ₅ , LiX-Li ₂ S-P ₂ S ₅ , LiX-Li ₂ S-SiS ₂ , LiX-Li ₂ S-B ₂ S ₃ (X: I, Br, or Cl), etc. Examples of the hydrides include LiBH ₄ -LiI-based complex hydrides and LiBH ₄ -LiNH ₂ -based complex hydrides, etc.

(Positive electrode current collector)
A positive electrode current collector is usually disposed on the outside of the positive electrode layer. A metal foil may be used as the positive electrode current collector. Examples of materials for the positive electrode current collector (e.g., metal foil) include aluminum, magnesium, stainless steel, titanium, iron, cobalt, zinc, tin, or alloys thereof. Lead tabs are connected to the positive electrode current collector and the negative electrode current collector as necessary.

(Negative electrode current collector)
A negative electrode current collector is usually disposed on the outside of the negative electrode layer. The negative electrode current collector may be a metal foil. Examples of materials for the negative electrode current collector (e.g., metal foil) include copper, nickel, stainless steel, titanium, or alloys thereof.

(Method of forming laminate (S))
The method for forming the laminate (S) is not particularly limited, and may be a known forming method. The laminate (S) is preferably formed using a material that does not contain a liquid component. An example of a method for forming the laminate (S) by such a forming method (dry forming method) will be described below.

First, the material of the positive electrode layer, the material of the solid electrolyte layer, and the material of the negative electrode layer are stacked on a metal foil (current collector) in a predetermined order, and then the current collector (metal foil) is placed. Next, the stacked materials and the metal foil are pressed together (main press) to form a laminate (S). This main press integrates the metal foil and each layer to obtain the laminate (S). The pressure of the main press can be changed appropriately depending on the material and thickness, and may be 50 MPa or more and 5000 MPa or less (for example, 300 MPa or more and 3000 MPa or less). In this way, a laminate (S) having a structure of positive electrode collector/positive electrode layer/solid electrolyte layer/negative electrode layer/negative electrode collector is obtained. The laminate (S) may include layers other than these layers, such as a thin conductive layer.

The materials may be preliminarily pressed at any stage after the material for the positive electrode layer is placed, the material for the solid electrolyte layer is placed, or the material for the negative electrode layer is placed. The preliminarily pressed is usually performed at a pressure lower than the pressure of the main press described above. There is no particular limit to the pressure of the preliminarily pressed, and it may be in the range of 1 MPa to 10 MPa. In order to reduce voids in the laminate, at least a part of the process of forming the laminate may be performed under reduced pressure.

By forming the laminate (S) using a process of pressing materials that do not contain liquid components, it is possible to obtain an all-solid-state battery that exhibits high performance without high pressure. As a method for arranging materials that do not contain liquid components (dispersion medium) in layers, electrostatic spraying, squeegee film formation, electrostatic painting, etc. may also be used.

When the laminate (S) includes multiple unit batteries, a laminate including one unit battery may be formed by press molding, and then the laminate may be stacked to form the laminate (S). Alternatively, the laminate (S) may be formed by press molding the materials so that multiple unit batteries are stacked.

Below, examples of embodiments according to the present disclosure will be described with reference to the drawings. The embodiments described below may be modified based on the above description. Furthermore, the matters described below may be applied to the above embodiments. Note that the following figures are schematic diagrams and are not drawn to actual scale. In the following figures, some components may be omitted in order to make the figures easier to see. Furthermore, in the following figures, the cross section of the exterior body may be indicated by a line.

(Embodiment 1)
In the embodiment 1, an example of the manufacturing method (M1) will be described. In the manufacturing method of the embodiment 1, a laminate 110 (laminate (S)) is used. A top view of the laminate 110 is shown in FIG. 1A. A cross-sectional view along the line IB-IB in FIG. 1A is shown in FIG. 1B.

The laminate 110 includes a positive electrode collector 111, a unit battery 113, and a negative electrode collector 112. The unit battery 113 includes a positive electrode layer 113a, a solid electrolyte layer 113b, and a negative electrode layer 113c. These layers and collectors are stacked in a stacking direction SD. The laminate 110 may be formed by the process described above.

A positive electrode lead tab 121 and a negative electrode lead tab 122 protrude from the laminate 110. The positive electrode lead tab 121 may be integral with the positive electrode current collector 111, or may be a lead tab connected to the positive electrode current collector 111. The negative electrode lead tab 122 may be integral with the negative electrode current collector 112, or may be a lead tab connected to the negative electrode current collector 112.

First, as shown in FIG. 2A, a resin-containing material (first resin-containing material) 201a that has not yet completely hardened and has fluidity is placed in an exterior body 120 having an opening (step (i)). A cross-sectional view of the exterior body 120 taken along line IIIA-IIIA in FIG. 2A is shown in FIG. 3A.

The exterior body 120 includes an angular tube portion 120a and a bottom portion 120b that seals one end of the angular tube portion 120a. The other end of the angular tube portion 120a is open as an opening portion 120t. The angular tube portion 120a is composed of two opposing main walls 120am and two side walls 120as that connect the two main walls 120am. A cross-sectional view of another example of the exterior body 120 is shown in FIG. 3B. When the exterior body 120 shown in FIG. 3B is not housing anything, the two main walls 120am are curved so as to be convex toward the inside. In other words, the main walls 120am have a ridge-like shape that is convex toward the inside. By using the exterior body 120, it is possible to pressurize the laminate 110 in the stacking direction SD.

Next, the laminate 110 is inserted into the exterior body, and then the curing of the resin-containing material 201a is completed (step (ii)). As a result, as shown in FIG. 2B, the cured resin-containing material (first resin-containing material) 201b is disposed between the exterior body 120 and the laminate 110. In this manner, the all-solid-state battery 100 is obtained. The positive electrode lead tab 121 and the negative electrode lead tab 122 protrude from the cured resin-containing material 201b.

As described above, in step (ii), the laminate 110 may be inserted into the exterior body 120 with the exterior body 120 pulled outward. The cross-sectional shape of the exterior body 120 in the state in which the exterior body 120 is pulled outward is shown diagrammatically in FIG. 3C. The state shown in FIG. 3C is a state in which the center of the main wall 120am in the width direction WD is pulled outward. The width direction WD is the direction connecting the two side walls 120as.

As described above, in step (ii), the resin-containing material 201a may be cured while the exterior body is pressurized from the outside. Specifically, the resin-containing material 201a may be cured while the main wall 120am is pressurized inward.

(Embodiment 2)
In the second embodiment, an example of the manufacturing method (M2) will be described. In the manufacturing method of the second embodiment, a laminate 110 (laminate (S)) is used. The laminate 110 has been described in the first embodiment, so a duplicated description will be omitted.

First, as shown in FIG. 4A, the laminate 110 is placed in an exterior body 120 having an opening 120t (step (I)). The exterior body 120 has been described in embodiment 1, so a duplicate description will be omitted.

Next, the supply of the resin-containing material having fluidity that has not yet been cured is started from the lower side inside the exterior body 120 to fill the resin-containing material inside the exterior body 120, and then the curing of the resin-containing material is completed (step (II)). As a result, as shown in FIG. 4B, the cured resin-containing material 201b is disposed between the exterior body 120 and the laminate 110. In this manner, the all-solid-state battery 100 is obtained. The positive electrode lead tab 121 and the negative electrode lead tab 122 protrude from the cured resin-containing material 201b.

The resin-containing material may be filled into the exterior body 120 using a nozzle (tube) 210 as shown in FIG. 5. The height H of the exterior body 120 in the arrangement of the exterior body 120 shown in FIG. 5 is shown in FIG. The supply of the resin-containing material is started from the lower side of the internal space of the exterior body 120, that is, from a position lower than a height of H/2 from the inner surface of the bottom 120b. For this reason, at least at the start of the supply of the resin-containing material, the nozzle 210 is arranged so that the tip of the nozzle 210 reaches the lower side of the exterior body 120, and the resin-containing material is supplied into the exterior body 120 from the tip of the nozzle 210. The position of the nozzle 210 (the position of the tip of the nozzle 210) may be the same until the filling of the resin-containing material is completed. Alternatively, the nozzle 210 may be gradually raised as the resin-containing material is filled.

In Figures 4A and 4B, an example is described in which step (I) and step (II) are performed with the bottom 120b of the exterior body 120 positioned downward. However, step (I) and step (II) may be performed with a part of the exterior body 120 other than the bottom 120b positioned downward.

FIG. 6 shows an example in which one of the main walls 120am is arranged downward. The height H of the exterior body 120 in the arrangement of the exterior body 120 shown in FIG. 6 is also shown in FIG. 6. When step (II) is performed in the arrangement of FIG. 6, it may be performed with the opening 120t sealed with the lid 130. In this case, step (II) may be performed by forming a through-hole on the lower side of the exterior body 120 in the arrangement of FIG. 6, and filling the exterior body 120 with the resin-containing material through the through-hole. Alternatively, a gap or through-hole may be formed on the lower side of the lid 130, and the resin-containing material may be filled into the exterior body 120 through the gap or through-hole.

Note that while Figures 4A and 4B show an example in which the exterior body 120 is arranged so that the bottom 120b is parallel to the horizontal plane, the bottom 120b may be inclined relative to the horizontal plane. Also, Figure 6 shows an example in which the exterior body 120 is arranged so that the main wall 120am is parallel to the horizontal plane, but the main wall 120am may be inclined relative to the horizontal plane. In either case, the height of the exterior body refers to the length of the exterior body along the vertical direction.

(Additional Note)
The above description discloses the following invention examples.
(Example 1)
A method for producing an all-solid-state battery including at least one unit cell including a positive electrode layer, a negative electrode layer, and a solid electrolyte layer disposed between the positive electrode layer and the negative electrode layer, comprising:
A step (i) of disposing a first resin-containing material having flowability and not yet cured in an exterior body having an opening;
and (ii) completing curing of the first resin-containing material after inserting a laminate including the at least one unit battery into the exterior body, and disposing the cured first resin-containing material between the exterior body and the laminate.
(Example 2)
The manufacturing method according to Example 1, wherein in the step (ii), the laminate is inserted into the exterior body while the exterior body is pulled outward.
(Example 3)
The manufacturing method according to Example 1 or 2, wherein in the step (ii), the laminate is inserted into the outer casing in a state in which a second resin-containing material is applied to a surface of the laminate.
(Example 4)
The manufacturing method described in Invention Example 3, wherein the first resin-containing material and the second resin-containing material contain the same resin.
(Example 5)
The manufacturing method according to any one of Examples 1 to 4, wherein in the step (ii), the first resin-containing material is cured in a state in which the outer casing is pressurized from the outside.
(Example 6)
A manufacturing method described in Example 5, wherein the thickness of the central portion of the outer casing after step (ii) is smaller than the thickness of the central portion of the outer casing before step (ii) is performed.
(Example 7)
The method of any one of Invention Examples 1 to 6, wherein the step (i) and the step (ii) are carried out under reduced pressure.
(Example 8)
A method for producing an all-solid-state battery including at least one unit cell including a positive electrode layer, a negative electrode layer, and a solid electrolyte layer disposed between the positive electrode layer and the negative electrode layer, comprising:
a step (I) of disposing a laminate including at least one unit battery in an exterior body having an opening;
and (II) supplying a resin-containing material that has not yet been cured and has fluidity from a lower side of the exterior body to fill the exterior body with the resin-containing material, and then completing the curing of the resin-containing material, thereby disposing the cured resin-containing material between the exterior body and the laminate.
(Example 9)
In the step (II),
The manufacturing method described in Example 8 of the present invention, in which the resin-containing material having fluidity is filled into the exterior body while the exterior body is pulled outward, and then the resin-containing material is hardened while the exterior body is pressurized from the outside.
(Example 10)
The method according to claim 8 or 9, wherein step (II) is carried out under reduced pressure.
(Example 11)
The manufacturing method according to any one of Examples 1 to 10, wherein the exterior body is made of metal.
(Example 12)
The manufacturing method described in Example 11, wherein the outer casing is an outer casing that presses the laminate in the stacking direction.

The present disclosure can be used for a manufacturing method of an all-solid-state battery.
Although the present invention has been described with respect to the presently preferred embodiments, such disclosure should not be interpreted as limiting. Various variations and modifications will no doubt become apparent to those skilled in the art to which the present invention pertains upon reading the above disclosure. Accordingly, the appended claims should be interpreted to cover all variations and modifications without departing from the true spirit and scope of the present invention.

100: All-solid-state battery 110: Laminate 113: Unit battery 113a: Cathode layer 113b: Solid electrolyte layer 113c: Negative electrode layer 120: Exterior body 120a: Square tube portion 120am: Main wall 120as: Side wall 120b: Bottom portion 120t: Opening 201a: Resin-containing material (first resin-containing material, before curing is completed)
201b: Resin-containing material (first resin-containing material, after curing)
210: Nozzle

Claims

A method for producing an all-solid-state battery including at least one unit cell including a positive electrode layer, a negative electrode layer, and a solid electrolyte layer disposed between the positive electrode layer and the negative electrode layer, comprising:
A step (i) of disposing a first resin-containing material having flowability and not yet cured in an exterior body having an opening;
and (ii) completing curing of the first resin-containing material after inserting a laminate including the at least one unit battery into the exterior body, and disposing the cured first resin-containing material between the exterior body and the laminate.
The manufacturing method according to claim 1, wherein in step (ii), the laminate is inserted into the exterior body while the exterior body is pulled outward.
The manufacturing method according to claim 1 or 2, wherein in step (ii), the laminate is inserted into the exterior body with a second resin-containing material applied to the surface of the laminate.
The manufacturing method according to claim 3, wherein the first resin-containing material and the second resin-containing material contain the same resin.
The manufacturing method according to claim 1 or 2, wherein in step (ii), the first resin-containing material is cured while the exterior body is pressurized from the outside.
The manufacturing method according to claim 5, wherein the thickness of the central portion of the exterior body after step (ii) is smaller than the thickness of the central portion of the exterior body before step (ii) is performed.
The method according to claim 1 or 2, wherein steps (i) and (ii) are carried out under reduced pressure.
A method for producing an all-solid-state battery including at least one unit cell including a positive electrode layer, a negative electrode layer, and a solid electrolyte layer disposed between the positive electrode layer and the negative electrode layer, comprising:
a step (I) of disposing a laminate including at least one unit battery in an exterior body having an opening;
and (II) supplying a resin-containing material having fluidity that has not yet been cured from a lower side of the exterior body to fill the exterior body with the resin-containing material, and then completing the curing of the resin-containing material, thereby disposing the cured resin-containing material between the exterior body and the laminate.
In the step (II),
The manufacturing method according to claim 8, further comprising filling the resin-containing material having fluidity into the exterior body while the exterior body is pulled outward, and then curing the resin-containing material while the exterior body is pressurized from the outside.
The method according to claim 8 or 9, wherein step (II) is carried out under reduced pressure.
The manufacturing method according to claim 1 or 8, wherein the exterior body is made of metal.
The manufacturing method according to claim 11, wherein the exterior body presses the laminate in the stacking direction.