Manufacturing method for all-solid-state batteries

Abstract

To provide a manufacturing method of an all-solid-state battery capable of easily manufacturing an all-solid-state battery that hardly expands even under reduced pressure.SOLUTION: A disclosed manufacturing method is a manufacturing method of an all-solid-state battery including at least one unit battery that includes a positive electrode layer, a negative electrode layer, and a solid electrolyte layer placed between the positive electrode layer and the negative electrode layer. The manufacturing method includes: a step (i) in which a first resin-containing material having fluidity that has not completely cured is placed in an outer casing with an opening; and a step (ii) in which, after inserting a laminate 110 including at least one unit battery into an exterior body 120, the curing of the first resin-containing materials is completed, and the cured first resin-containing materials 201b is placed between the exterior body 120 and the laminate 110.SELECTED DRAWING: Figure 2B

Description

[Technical Field]

[0001] The present disclosure relates to a method for manufacturing an all-solid-state battery. [Background technology]

[0002] Currently, all-solid-state batteries, which have high safety and energy density, are attracting attention. All-solid-state batteries include a laminate including a positive electrode layer, a solid electrolyte layer, and a negative electrode layer as a power generating element. Various proposals have been made regarding the structure and manufacturing method of all-solid-state batteries.

[0003] 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 an end surface of the laminated electrode body, wherein the electrode mixture layer contains an active material and a binder resin, and 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 The following all-solid-state battery is described.

[0004] Claim 1 of Patent Document 2 (Japanese Patent No. 6673249) describes "a method for manufacturing a laminated all-solid-state battery, the method comprising: housing an all-solid-state battery stack having one or more all-solid-state battery elements, each of which is formed by laminating 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, in an exterior body made of a laminate film; applying pressure to the all-solid-state battery stack housed in the exterior body in a 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 pressurizing 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."

[0005] Claim 1 of Patent Document 3 (Japanese Patent No. 6772855) describes "an all-solid-state battery comprising: an all-solid-state battery element having one or more unit cells each having 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 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 sealing body sealing the opening and in contact with a surface of the all-solid-state battery element facing the opening; and an anode current collector layer protruding portion and a cathode current collector layer protruding portion protruding from the resin sealing body to a side opposite to the all-solid-state battery element, wherein the resin sealing body fills at least a part of a gap between an outer periphery of the all-solid-state battery element and an inner periphery of the metal exterior body to form a gap filler, and the resin sealing body is a curable resin." [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 2019-207840 [Patent Document 2] Patent No. 6673249 [Patent Document 3] Patent No. 6772855 Summary of the Invention [Problem to be solved by the invention]

[0007] 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, resulting in a decrease in battery performance. Even when 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. [Means for solving the problem]

[0008] One aspect of the present disclosure relates to a first method for manufacturing an all-solid-state battery, the first method 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 first method including the steps of: (i) disposing an incompletely cured, fluid first resin-containing material in an outer casing having an opening; and (ii) inserting a stack including the at least one unit battery into the outer casing, allowing the first resin-containing material to complete curing, and disposing the cured first resin-containing material between the outer casing and the stack.

[0009] One aspect of the present disclosure relates to a second method for manufacturing an all-solid-state battery, the second method 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 method including the steps of: (I) disposing a stack including the at least one unit battery in an exterior body having an opening; and (II) supplying an incompletely cured, fluid resin-containing material starting from a 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, thereby disposing the cured resin-containing material between the exterior body and the stack. [Effects of the Invention]

[0010] According to the manufacturing method of the present disclosure, an all-solid-state battery that is less likely to expand even under reduced pressure can be easily manufactured. [Brief explanation of the drawings]

[0011] [Figure 1A] FIG. 1A is a top view schematically illustrating an example of a laminate used in the first embodiment. [Figure 1B] FIG. 1B is a cross-sectional view taken along line IB-IB in FIG. 1A. [Figure 2A] FIG. 2A is a cross-sectional view schematically showing one step of the manufacturing method of embodiment 1. FIG. [Figure 2B] FIG. 2B is a cross-sectional view schematically showing a step subsequent to the step shown in FIG. 2A. [Figure 3A] FIG. 3A is a cross-sectional view schematically illustrating an example of an exterior body used in the manufacturing method of embodiment 1. FIG. [Figure 3B] FIG. 3B is a cross-sectional view schematically showing another example of an exterior body used in the manufacturing method of embodiment 1. As shown in FIG. [Figure 3C] FIG. 3C is a cross-sectional view schematically showing an example of deformation of the exterior body in the manufacturing method of embodiment 1. FIG. [Figure 4A] FIG. 4A is a cross-sectional view schematically showing one step of the manufacturing method of embodiment 2. [Figure 4B] FIG. 4B is a cross-sectional view schematically showing a step subsequent to the step shown in FIG. 4A. [Figure 5] FIG. 5 is a cross-sectional view schematically illustrating an example of one step of the manufacturing method according to the second embodiment. [Figure 6] FIG. 6 is a cross-sectional view schematically showing another example of a step of the manufacturing method according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] The following describes embodiments of the present disclosure using examples, 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 lower and upper limits of numerical values ​​related to specific physical properties or conditions are exemplified, any of the exemplified lower limits and any of the exemplified upper limits can be arbitrarily combined, as long as the lower limit is not greater than the upper limit.

[0013] 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.

[0014] Manufacturing method (M1) and manufacturing method (M2) are methods 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. Manufacturing method (M1) and manufacturing method (M2) use a laminate including at least one unit cell. This laminate may be referred to as a "laminate (S)" below. Typically, a positive electrode lead tab and a negative electrode lead tab protrude from the laminate (S). Examples of the configuration of all-solid-state batteries 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.

[0015] (First manufacturing method (manufacturing method (M1))) In conventional manufacturing methods, the laminate (S) is placed inside an exterior body, and then a sealing resin is injected through an opening in the exterior body to surround the laminate (S). However, because the viscosity of the sealing resin is relatively high, it is difficult to inject the sealing resin without forming voids between the laminate (S) and the exterior body. If a large void 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.

[0016] As described below, in the manufacturing method (M1), the first resin-containing material is disposed in the outer casing beforehand, and then the laminate (S) is inserted into the outer casing. Therefore, the manufacturing method (M1) can prevent the formation of a large void between the laminate (S) and the outer casing 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 the manufacturing method (M1), since it is easy to dispose the first resin-containing material in the outer casing, the all-solid-state battery can be easily manufactured.

[0017] 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.

[0018] (Step (i)) Step (i) is a step of placing a first resin-containing material that has fluidity and has not yet completely hardened inside an exterior body having an opening. The exterior body having an opening can be, for example, a rectangular cylindrical exterior body with a bottom. The rectangular cylindrical portion has two main walls (plate-shaped portions) and two side walls connecting the two main walls. One end of the rectangular cylindrical portion is sealed at the bottom, and the other end is open as an opening.

[0019] 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) including 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. The use of an epoxy resin strengthens the bonding strength between the two main walls. As a result, swelling of the exterior body under reduced pressure can be particularly suppressed. Because silicone resin has high viscoelasticity, the use of silicone resin can cushion impacts on the laminate (S), thereby improving the impact resistance of the battery.

[0020] The first resin-containing material may include a filler dispersed in the resin, such as an inorganic filler such as alumina particles or silica particles.

[0021] 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 is no limitation on the method for 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.

[0022] The viscosity of the first resin-containing material placed in the exterior package 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 this 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. Setting the viscosity to 20 Pa·s or less (e.g., 10 Pa·s or less or 5.0 Pa·s or less) makes it easier to place the first resin-containing material in the exterior package and to insert the laminate (S) into the exterior package in step (ii). Using a silicone resin makes it easier to obtain a first resin-containing material with low viscosity. The viscosity of a resin-containing material containing a silicone resin can be measured using a Brookfield rotational viscometer.

[0023] The amount of the first resin-containing material placed in the exterior packaging in step (i) is an amount that will cover a certain portion of the surface of the laminate (S) when the laminate (S) is inserted into the exterior packaging in step (ii). For example, this amount is preferably an amount that will cover 30% or more, 50% or more, 70% or more, or 90% or more of the total surface area of ​​the laminate (S) when the laminate (S) is inserted into the exterior packaging in step (ii). This amount may be an amount that will cover the entire surface of the laminate (S) when the laminate (S) is inserted into the exterior packaging in step (ii). Alternatively, this amount may be an amount that will cover the end face of the laminate (S) other than the end face on the opening side of the exterior packaging.

[0024] (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 arranging the cured first resin-containing material between the outer casing and the laminate.

[0025] The laminate (S) can be inserted through an opening in the exterior body. After the laminate (S) is inserted into the exterior body, the first resin-containing material may be added to the interior of the exterior body. It is preferable that the entire laminate (S) is ultimately covered with the first resin-containing material.

[0026] The method for completing the curing of the first resin-containing material is not limited and is selected depending on the type of resin contained in the first resin-containing material. For example, if a heat-curable resin is used, the first resin-containing material may be cured by heating. Alternatively, if a time-curable resin is used, the first resin-containing material may be cured by simply leaving it.

[0027] In this way, an all-solid-state battery is obtained that includes the laminate (S) fixed inside the exterior body by the cured first resin-containing material, and the exterior body.

[0028] 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 sucked by vacuum suction or the like and pulled outward. Alternatively, the opening of the exterior body may be widened using a jig or the like. These methods can also be used in manufacturing method (M2).

[0029] 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.

[0030] The second resin-containing material can be made of the materials 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 firmly fix the resin-containing material in the exterior body to the laminate (S). The first resin-containing material and the second resin-containing material may be made of the same material. Alternatively, the first resin-containing material and the second resin-containing material may contain the same resin but be made of different materials overall. Alternatively, the first resin-containing material and the second resin-containing material may not contain the same resin but be made of different materials.

[0031] 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 pressed toward the inside of the exterior body. This configuration allows the laminate (S) to be sealed while being pressurized in the stacking direction. Pressurizing the laminate (S) in the stacking direction allows the battery to fully exhibit its performance. Furthermore, this configuration can prevent the battery from expanding under reduced pressure.

[0032] In step (ii), when the first resin-containing material is cured while the outer casing is pressurized from the outside, the thickness of the central portion of the outer casing after step (ii) may be smaller than the thickness of the central portion of the outer casing before step (ii). According to this configuration, the laminate (S) can be sealed while being strongly pressurized in the stacking direction. Note that the central portion of the outer casing means the central portion of one of the main walls of the outer casing when the wall is viewed from above.

[0033] 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 arrange the first resin-containing material inside the exterior body. By performing step (ii) under reduced pressure, it is possible to prevent voids from forming between the exterior body and the laminate (S). As a result, it is possible to prevent the manufactured all-solid-state battery from expanding when placed under reduced pressure.

[0034] (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) placed 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), it is easy to fill the exterior body with the first resin-containing material, so that the all-solid-state battery can be easily manufactured.

[0035] The second manufacturing method (manufacturing method (M2)) of an all-solid-state battery includes steps (I) and (II) in this order. These steps are described below.

[0036] (Process (I)) Step (I) is a step of placing a laminate (S) including at least one unit cell in an exterior body having an opening. The laminate (S) can be placed inside the exterior body through the opening. The exterior body having an opening can be any of the exterior bodies exemplified in the description of manufacturing method (M1).

[0037] 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 packaging. In this case, it becomes easier to fill the resin-containing material (first resin-containing material) used in step (II). The resin-containing material (first resin-containing material) used in step (II) can 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) can be the second resin-containing material exemplified in the description of manufacturing method (M1).

[0038] (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 a fluid resin-containing material that has not yet been cured from the lower side of the exterior body, filling the interior of the exterior body with the resin-containing material, and then completing the curing of the resin-containing material. The method for completing the curing of the resin-containing material is not limited and is selected depending on the type of resin contained in the resin-containing material. For example, when a heat-curable resin is used, the resin-containing material may be cured by heating. Furthermore, when a resin that cures over time is used, the resin-containing material may be cured by simply leaving it.

[0039] 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 the resin-containing material has not yet fully hardened has been described in manufacturing method (M1), so a duplicated 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).

[0040] In step (II), the lower side of the exterior body refers to a side below the center in the vertical direction of the internal space of the exterior body when the exterior body is positioned 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.

[0041] There is no particular limitation on the method for supplying the resin-containing material from the lower side of 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 of 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 curing of the resin-containing material is completed. Note that the nozzle may be gradually pulled back toward the opening as the resin-containing material is filled into the exterior body. At least when the supply of the resin-containing material begins, the resin-containing material is supplied from the lower side of the exterior body.

[0042] Step (II) is usually performed with the exterior body positioned so that the bottom is facing downward and the opening is facing upward. However, step (II) may also be performed with the exterior body positioned in a different direction. For example, step (II) may be performed with the exterior body positioned so that one main wall is facing downward and the other main wall is facing upward. Alternatively, step (II) may be performed with the exterior body positioned so that one side wall is facing downward and the other side wall is facing upward. In these cases, the resin-containing material may be filled into the exterior body with the opening partially or entirely covered.

[0043] In step (II), the exterior body may be pulled outward, and a fluid resin-containing material may be filled into the exterior body, and then the resin-containing material may be cured while the exterior body is pressurized from the outside. This configuration allows the laminate (S) to be sealed while being pressurized in its stacking direction. Pressurizing the laminate (S) in the stacking direction allows the battery to fully exhibit its performance. This configuration also makes it possible to suppress battery expansion under reduced pressure.

[0044] 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, the resin-containing material can be easily filled into the exterior body. Furthermore, by performing step (II) under reduced pressure, the formation of voids between the exterior body and the laminate (S) can be suppressed. As a result, the expansion of the produced all-solid-state battery when placed under reduced pressure can be suppressed.

[0045] In the manufacturing methods (M1) and (M2), the exterior body may be made of a metal, examples of which will be described later.

[0046] In manufacturing methods (M1) and (M2), the exterior body may be an exterior body that presses the laminate (S) in the stacking direction. An example of such an exterior body is an exterior body in which, when nothing is housed, two main walls are curved so as to convex inward. 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 manufacturing methods (M1) and (M2), resin is filled between the exterior body and the laminate (S). This makes it easier for the pressure from the exterior body to be uniformly transmitted to the laminate (S).

[0047] When two main walls that are curved convexly inward are used, the shape and size of the exterior body are selected so that when the laminate and the resin-containing material are housed, the main walls become flatter than before they are housed in. With this configuration, the main walls can apply pressure to the laminate (S) in the stacking direction.

[0048] 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 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. The third manufacturing method includes a step (Ia) of disposing a stack 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 stack by starting the supply of an incompletely cured, fluid resin-containing material from below a resin-filled region in the exterior body, filling the resin-filled region with the resin-containing material, and then completing the curing of the resin-containing material.

[0049] Step (Ia) is the same as step (I) of manufacturing method (M2), except that the internal space of the exterior body may be partitioned into upper and lower sections, so a redundant description 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 separate the internal space of the exterior body. The partition is formed around the periphery of the laminate. In manufacturing method (M3), a rectangular cylindrical body with a bottom may be used as the exterior body, as described in manufacturing method (M2).

[0050] Step (IIa) is a process in which the step (II) in manufacturing method (M2) of "starting the supply of a resin-containing material having fluidity that has not yet cured from the lower side of the outer casing, filling the resin-containing material into the outer casing, and then completing the curing of the resin-containing material" is replaced with the step of "starting the supply of a resin-containing material having fluidity that has not yet cured from the lower side of the resin-filled region of the outer casing, filling the resin-containing material into the resin-filled region, and then completing the curing of the resin-containing material." Except for this substitution, the matters described in step (II) are applicable to step (IIa). Furthermore, the matters described in manufacturing method (M2) are applicable to manufacturing method (M3), except for the differences between steps (I) and (Ia) and between steps (II) and (IIa). From one perspective, manufacturing method (M2) can be considered to be included in manufacturing method (M3).

[0051] In step (IIa), the resin-filled region refers to the space into which the resin-containing material is filled. In step (IIa), the lower side of the resin-filled region refers to the side below the vertical center of the resin-filled region in the arrangement of the outer casing when filling the resin-containing material. In this case, when the height of the resin-filled region (the length of the resin-filled region in the vertical direction) is Ha, the supply of the resin-filled material may be started below a height of Ha / 3 from the bottom of the resin-filled region. Alternatively, the supply of the resin-filled material may be started below a height of Ha / 4 from the bottom of the resin-filled region, or below a height of Ha / 5 from the bottom of the resin-filled region.

[0052] In manufacturing method (M3), the internal space of the outer package may be divided into two spaces (a lower space and an upper space) by a partition disposed around the periphery of the laminate. For example, in step (Ia), a laminate having a ridge-like portion disposed around the periphery as a partition may be disposed within the outer package, thereby dividing the internal space of the outer package into two spaces. In this case, two resin-filled regions are formed within the outer package. In step (IIa), first, supply of a fluid resin-containing material is initiated from the lower side of the upper space (one of the resin-filled regions) to fill the space, and then the resin-containing material is cured. Next, the outer package is turned upside down, and supply of a fluid resin-containing material is initiated from the lower side of the other space (the other resin-filled region) to fill the space, and then the resin-containing material is cured. In this way, the cured resin-containing material can be disposed in two spaces (two resin-filled regions).

[0053] (Components of all-solid-state batteries) The all-solid-state battery manufactured by manufacturing method (M1) and the all-solid-state battery manufactured by manufacturing method (M2) basically have the same configuration. Examples of components of the all-solid-state batteries manufactured by manufacturing method (M1) and manufacturing method (M2) are described below. However, the following components are merely examples, and other components may be used. Note that the following mainly describes an example of an all-solid-state lithium-ion battery, but 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.

[0054] 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 a plurality of stacked unit cells. 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 needed. 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.

[0055] (exterior body) As described above, the exterior body can be a metal case, etc. Examples of metal plates that can form the case include stainless steel plates, carbon steel plates, and aluminum alloy plates.

[0056] The thickness of the metal plate constituting the exterior body may be selected depending on 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, or may be 0.60 mm or less, or 0.50 mm or less.

[0057] (positive electrode layer) The positive electrode layer contains a positive electrode active material and may contain other components as needed. Examples of the other components include known components (binders, conductive materials, etc.) used in the positive electrode layer of all-solid-state batteries. From the viewpoint of enhancing the lithium ion conductivity in the positive electrode layer, the positive electrode layer may contain a solid electrolyte exhibiting lithium ion conductivity together with the positive electrode active material. Typically, the positive electrode active material is used in the form of particles (powder).

[0058] The positive electrode active material can be any material that can be used as a positive electrode active material in an all-solid-state battery. In the case of an all-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 Examples of compounds other than oxides include olivine compounds (LiMPO4, etc.) and sulfur-containing compounds (LiS, 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.

[0059] (negative electrode layer) The negative electrode layer contains a negative electrode active material and may contain other components as needed. Examples of the other components include known components (binders, conductive materials, etc.) used in the negative electrode layer of all-solid-state batteries. The negative electrode layer may contain a negative electrode active material and a solid electrolyte exhibiting lithium ion conductivity. Typically, the negative electrode active material is used in the form of particles (powder).

[0060] The negative electrode active material may be a material that can be used as a negative electrode active material for all-solid-state batteries. In the case of all-solid-state lithium-ion batteries, the negative electrode active material may be a specific material (such as a carbonaceous material, a metal or semimetal element, alloy, or compound) that can reversibly absorb 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 elemental 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. For example, silicon oxide and a carbonaceous material may be used in combination. Particles containing graphite particles and amorphous carbon coating the graphite particles may also be used as the negative electrode active material.

[0061] (solid electrolyte layer) The solid electrolyte layer is disposed between the positive electrode layer and the negative electrode layer. The solid electrolyte layer contains a solid electrolyte and may contain other components as needed. 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).

[0062] 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 a substance 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).

[0063] Examples of sulfides include Li2S-SiS2, Li2S-P2S5, Li2S-GeS2, Li2S-B2S3, Li2S-Ga2S3, Li2S-Al2S3, Li2S-GeS2-P2S5, Li2S-Al2S3-P2S5, Li2S-P2S3, Li2S-P2S3-P2S5, LiX-Li2S-P2S5, LiX-Li2S-SiS2, LiX-Li2S-B2S3 (X: I, Br, or Cl), etc. Examples of hydrides include LiBH4-LiI-based complex hydrides and LiBH4-LiNH2-based complex hydrides, etc.

[0064] (Positive electrode current collector) A positive electrode current collector is usually disposed on the outside of the positive electrode layer. The positive electrode current collector may be a metal foil. 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 needed.

[0065] (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, and alloys thereof.

[0066] (Method for forming laminate (S)) The method for forming the laminate (S) is not particularly limited, and it may be formed by 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.

[0067] First, the materials for the positive electrode layer, the solid electrolyte layer, and the negative electrode layer are stacked in a predetermined order on a metal foil (current collector), and then a current collector (metal foil) is placed on top. Next, the stacked materials and 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 adjusted appropriately depending on the material and thickness, and may be 50 MPa or more and 5000 MPa or less (e.g., 300 MPa or more and 3000 MPa or less). In this manner, a laminate (S) having a structure of positive electrode current collector / positive electrode layer / solid electrolyte layer / negative electrode layer / negative electrode current collector is obtained. Note that the laminate (S) may also include layers other than these layers, such as a thin conductive layer.

[0068] The materials may be preliminarily pressed at any stage after disposing the material for the positive electrode layer, disposing the material for the solid electrolyte layer, or disposing the material for the negative electrode layer. The preliminarily pressed is usually performed at a pressure lower than the pressure used for the main press. The preliminarily pressed pressure is not particularly limited and 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.

[0069] 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 applying 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.

[0070] When the laminate (S) includes a plurality of unit batteries, a laminate including one unit battery may be formed by press molding, and then these laminates may be stacked to form the laminate (S). Alternatively, the laminate (S) may be formed by press molding the materials so that a plurality of unit batteries are stacked.

[0071] Examples of embodiments according to the present disclosure will be described below 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-described 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 to make the figures easier to see. Furthermore, in the following figures, cross sections of exterior bodies may be indicated by lines.

[0072] (Embodiment 1) In embodiment 1, an example of a manufacturing method (M1) will be described. In the manufacturing method of 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 taken along line IB-IB in FIG. 1A is shown in FIG. 1B.

[0073] The laminate 110 includes a positive electrode current collector 111, a unit battery 113, and a negative electrode current 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 current collectors are stacked in the stacking direction SD. The laminate 110 may be formed by the process described above.

[0074] 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.

[0075] 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.

[0076] The exterior body 120 includes a rectangular tube portion 120a and a bottom portion 120b that seals one end of the rectangular tube portion 120a. The other end of the rectangular tube portion 120a is open as an opening 120t. The rectangular tube portion 120a is composed of two opposing main walls 120am and two side walls 120as that connect the two main walls 120am. FIG. 3B shows a cross-sectional view of another example of the exterior body 120. When the exterior body 120 shown in FIG. 3B is empty, the two main walls 120am are curved so as to convex inward. In other words, the main walls 120am have a ridge-like shape that convex inward. Using the exterior body 120, it is possible to apply pressure to the stacked body 110 in the stacking direction SD.

[0077] Next, the laminate 110 is inserted into an 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.

[0078] 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 where the exterior body 120 is pulled outward is schematically shown in Fig. 3C. The state shown in Fig. 3C is a state where the center portion of the main wall 120am in the width direction WD is pulled outward.

[0079] As described above, in the step (ii), the resin-containing material 201a may be cured while the exterior body is being pressurized from the outside. Specifically, the resin-containing material 201a may be cured while the main wall 120am is being pressurized inward.

[0080] (Embodiment 2) In embodiment 2, an example of the manufacturing method (M2) will be described. In the manufacturing method of embodiment 2, a laminate 110 (laminate (S)) is used. The laminate 110 has been described in embodiment 1, so a duplicated description will be omitted.

[0081] 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 the first embodiment, so a duplicated description will be omitted.

[0082] Next, the supply of the resin-containing material that has not yet been cured and has fluidity is started from the lower side inside the exterior body 120 to fill the interior of the exterior body 120 with the resin-containing material, 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.

[0083] 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 positioned 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 remain 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.

[0084] 4A and 4B illustrate an example in which steps (I) and (II) are performed with bottom 120b of exterior body 120 positioned downward. However, steps (I) and (II) may be performed with a part of exterior body 120 other than bottom 120b positioned downward.

[0085] FIG. 6 shows an example in which one main wall 120am is arranged downward. FIG. 6 also shows the height H of the exterior body 120 in the arrangement of 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 interior of the exterior body 120 with the resin-containing material through the through-hole. Alternatively, it is possible to form a gap or a through-hole on the lower side of the lid 130, and filling the interior of the exterior body 120 with the resin-containing material through the gap or through-hole.

[0086] 4A and 4B show an example in which the bottom 120b is arranged parallel to the horizontal plane, but the bottom 120b may be tilted relative to the horizontal plane. Also, while Fig. 6 shows an example in which the main wall 120am is arranged parallel to the horizontal plane, the main wall 120am may be tilted 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.

[0087] (Addendum) The above description discloses the following invention examples. (Example 1) 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, comprising: A step (i) of placing a first resin-containing material having fluidity 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 of the present invention, wherein in step (ii), the laminate is inserted into the exterior body while the exterior body is pulled outward. (Example 3) The manufacturing method according to Invention Example 1 or 2, wherein in step (ii), the laminate is inserted into the exterior body in a state where a second resin-containing material is applied to the surface of the laminate. (Example 4) The manufacturing method described in Example 3 of the present invention, 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 exterior body is pressurized from the outside. (Example 6) A manufacturing method according to Example 5 of the present invention, 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 production method of any one of Invention Examples 1 to 6, wherein the steps (i) and (ii) are carried out under reduced pressure. (Example 8) 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, comprising: a step (I) of disposing a stack 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 interior of the exterior body, 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 involves filling the outer casing with the fluid resin-containing material while the outer casing is pulled outward, and then hardening the resin-containing material while pressurizing the outer casing from the outside. (Example 10) The method according to Example 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) A manufacturing method according to Example 11 of the present invention, wherein the outer casing is an outer casing that presses the laminate in the stacking direction. [Industrial Applicability]

[0088] The present disclosure can be used in a method for manufacturing an all-solid-state battery. [Explanation of symbols]

[0089] 100: All-solid-state battery 110: Laminate 113: Unit battery 113a: Positive electrode layer 113b: Solid electrolyte layer 113c: Negative electrode layer 120: Exterior body 120a: Square tube part 120am: Main wall 120as: side wall 120b: Bottom 120t: opening 201a: Resin-containing material (first resin-containing material, before curing is completed) 201b: Resin-containing material (first resin-containing material, after curing is complete) 210: Nozzle

Claims

1. 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, comprising: Step (i) of disposing a first resin-containing material having fluidity and not yet cured in an exterior body having an opening; and (ii) a step of completing curing of the first resin-containing material after inserting a stack 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 stack; In the step (ii), the laminate is inserted into the exterior body in a state where the exterior body is pulled outward.

2. The manufacturing method according to claim 1 , wherein in the step (ii), the laminate is inserted into the exterior body in a state where a second resin-containing material is applied to a surface of the laminate.

3. The manufacturing method according to claim 2 , wherein the first resin-containing material and the second resin-containing material contain the same resin.

4. 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, comprising: Step (i) of disposing a first resin-containing material having fluidity and not yet cured in an exterior body having an opening; and (ii) a step of completing curing of the first resin-containing material after inserting a stack 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 stack; In the step (ii), the first resin-containing material is cured in a state in which the exterior body is pressurized from the outside.

5. The manufacturing method according to claim 4 , wherein the thickness of the central portion of the exterior body after the step (ii) is smaller than the thickness of the central portion of the exterior body before the step (ii) is performed.

6. The method according to claim 1 or 4, wherein the steps (i) and (ii) are carried out under reduced pressure.

7. 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, comprising: a step (I) of disposing a stack including at least one unit battery in an exterior body having an opening; and (II) supplying a resin-containing material that has not yet completely cured and has fluidity from a lower side of the exterior body to fill the interior of the exterior body, and then completing the curing of the resin-containing material, thereby disposing the cured resin-containing material between the exterior body and the laminate.

8. In the step (II), The manufacturing method according to claim 7, wherein 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.

9. The method according to claim 7 or 8, wherein step (II) is carried out under reduced pressure.

10. The manufacturing method according to claim 1 , wherein the exterior body is made of metal.

11. The manufacturing method according to claim 10 , wherein the outer casing applies pressure to the laminate in a stacking direction.

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