solid state batteries

Abstract

To provide a solid-state battery capable of preferably pressurizing a power generation element by means of a case.SOLUTION: A solid-state battery 100 includes a stored object 101 including a laminate 110 including a power generation element 112 and a metallic case (e.g., a cylindrical body 130) in which the stored object 101 is stored. The laminate 110 includes opposed two principal surfaces 110m. The case includes two tabular parts 130m which are opposed so as to hold the laminate 110 therebetween. At least one tabular part selected from the two tabular parts 130m includes a curved portion 130mc which is curved so as to have a shape projected toward the inside of the case in a non-stored state where the stored object 101 is not stored in the case. The case is shaped to generate a force of a spring in a direction, in which the two tabular parts 130m are connected, with respect to the two tabular parts 130nm. In a stored state where the stored object 101 is stored in the case, the two principal surfaces 110m are pressurized by the two tabular parts 130m.SELECTED DRAWING: Figure 2A

Description

[Technical Field]

[0001] The present disclosure relates to solid-state batteries. [Background technology]

[0002] Currently, solid-state batteries with high safety and energy density are attracting attention. Solid-state batteries include power generating elements including a positive electrode layer, a solid electrolyte layer, and a negative electrode layer. Solid-state batteries are generally considered to have better performance when used under pressure. Methods for pressurizing solid-state batteries have been proposed.

[0003] Patent Document 1 (JP 2015-95281 A) discloses "a charging system for an all-solid-state battery mounted on a vehicle, comprising a charging unit that charges the all-solid-state battery, a pressurizing unit that applies a confining pressure to the all-solid-state battery, and a pressure control unit that controls the confining pressure, wherein the pressure control unit instructs the pressurizing unit to make the confining pressure during charging higher than the confining pressure during discharging."

[0004] In the field of solid-state batteries, it has been a common practice to encapsulate power generating elements in a package formed from a laminate film. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2015-95281 Summary of the Invention [Problem to be solved by the invention]

[0006] One of the objects of the present disclosure is to provide a solid-state battery in which the power generating element can be preferably pressurized by the case. [Means for solving the problem]

[0007] One aspect of the present disclosure relates to a solid-state battery, including: a contained object including a laminate including a power-generating element; and a metal case that contains the contained object, wherein the power-generating element 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 includes two opposing main surfaces; the case includes two opposing plate-shaped members sandwiching the laminate; at least one selected from the two plate-shaped members includes a curved portion that is curved so as to have a convex shape toward the inside of the case when the case is in an uncontained state in which the contained object is not contained; the case has a shape that generates a spring force on the two plate-shaped members in a direction connecting the two plate-shaped members; and when the case is in a contained state in which the contained object is contained, the two plate-shaped members press against the two main surfaces.

[0008] Another aspect of the present disclosure relates to another solid-state battery, the solid-state battery including a contained object and a case for containing the contained object, the contained object including a laminate including a power generating element and a package enclosing the laminate, the power generating element 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 package being a bag-shaped package formed of a laminate film, the package including a joint portion joining one part of the laminate film to another part to form the bag-shaped package, the laminate including two opposing main surfaces, the joint portion including a laminate portion stacked on the laminate so as to be located on at least one selected from the two main surfaces, and the laminate portion being pressurized by the case. [Effects of the Invention]

[0009] According to the solid-state battery of the present disclosure, the power generating element can be preferably pressurized by the case. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a perspective view schematically showing a solid state battery according to a first embodiment. [Figure 2A]FIG. 2 is a cross-sectional view schematically showing the solid-state battery shown in FIG. [Figure 2B] FIG. 2 is a cross-sectional view schematically showing an example of the shape of a case when a laminate is not enclosed. [Figure 2C] FIG. 2 is a cross-sectional view schematically showing an example of the shape of a case when a laminate is enclosed therein. [Figure 3] FIG. 10 is a cross-sectional view schematically showing an example of a case of a comparative example. [Figure 4] 4 is a cross-sectional view schematically showing another example of the case used in the solid state battery of Embodiment 1. FIG. [Figure 5] 4 is a cross-sectional view schematically showing another example of the case used in the solid state battery of Embodiment 1. FIG. [Figure 6] FIG. 5 is a cross-sectional view illustrating the shape of the case shown in FIG. [Figure 7] FIG. 10 is a plan view showing the experimental results when an example of a case of a comparative example is used. [Figure 8] 10A and 10B are plan views showing experimental results when an example of the case of the first embodiment is used. [Figure 9] FIG. 3 is a cross-sectional view schematically illustrating an example of a solid state battery according to a second embodiment. [Figure 10] FIG. 10 is a cross-sectional view schematically showing an example of a laminate of the solid-state battery shown in FIG. [Figure 11] 10 is a top view showing a part of the solid-state battery shown in FIG. 9. [Figure 12] 10 is a cross-sectional view schematically showing a part of another example of the solid state battery of Embodiment 2. FIG. [Figure 13] 10 is a cross-sectional view schematically showing a part of another example of the solid state battery of Embodiment 2. FIG. [Figure 14] 10 is a cross-sectional view schematically showing a part of another example of the solid state battery of Embodiment 2. FIG. [Figure 15A] 5 is a diagram schematically illustrating a step of an example of a method for manufacturing a solid state battery according to Embodiment 2. FIG. [Figure 15B] FIG. 15B is a diagram schematically illustrating an example of a step subsequent to the step in FIG. 15A. [Figure 15C] FIG. 15C is a diagram schematically illustrating an example of a step subsequent to the step in FIG. 15B. [Figure 16A] 10 is a diagram schematically showing a step of another example of the method for producing the solid state battery of Embodiment 2. FIG. [Figure 16B] FIG. 16B is a diagram schematically illustrating an example of a step subsequent to the step in FIG. 16A. DETAILED DESCRIPTION OF THE INVENTION

[0011] 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.

[0012] In this specification, examples of solid-state batteries include batteries that do not contain a liquid component as a constituent of the electrolyte. For example, examples of solid-state batteries include batteries that do not contain a liquid component as a constituent necessary for functioning as a battery, more specifically, batteries that do not contain a liquid component. Here, "liquid component" means a component that is liquid at room temperature (25°C). Examples of solid-state batteries include batteries known as all-solid-state batteries, semi-solid-state batteries, pseudo-solid-state batteries, and all-resin batteries. Among these, the present disclosure is particularly suitable for batteries known as all-solid-state batteries. Therefore, in the following description, unless a particular contradiction occurs, "solid-state battery" may be read as "all-solid-state battery."

[0013] A solid-state battery includes a power generating element. The power generating element has a structure in which a positive electrode layer, a solid electrolyte layer, and a negative electrode layer are stacked. Hereinafter, the direction in which the positive electrode layer, the solid electrolyte layer, and the negative electrode layer are stacked may be referred to as the "stacking direction."

[0014] Two types of solid-state batteries (first and second solid-state batteries) according to the present disclosure will be described below. The first solid-state battery and the second solid-state battery may be referred to as "solid-state battery (S1)" and "solid-state battery (S2)," respectively.

[0015] (First solid-state battery (S1)) The solid-state battery (S1) includes a contained object including a laminate including a power generating element, and a metal case that contains the contained object. Hereinafter, the contained object and the laminate may be referred to as the "contained object (Z)" and the "laminated object (L)," respectively.

[0016] The power generating element 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 (L) includes two opposing main surfaces. The case includes two plate-shaped portions facing each other so as to sandwich the laminate (L). At least one plate-shaped portion selected from the two plate-shaped portions includes a curved portion that is curved so as to have a convex shape toward the inside of the case when the case is in an unaccommodated state in which the case does not accommodate an object (Z). The at least one plate-shaped portion including the curved portion may be referred to as a "plate-shaped portion (B)" below. The case has a shape that generates a spring force in the direction connecting the two plate-shaped portions (hereinafter may be referred to as the "direction MD") with respect to the two plate-shaped portions. When the case is in an accommodated state in which an object is accommodated, the two plate-shaped portions apply pressure to the two main surfaces of the laminate (L).

[0017] The case of the solid-state battery (S1) includes a plate-shaped portion (B) including a curved portion, and further has a shape that generates a spring force in the direction connecting the two plate-shaped portions. If the case does not have a shape that generates a spring force, the plate-shaped portion of the case cannot sufficiently press against the main surface of the laminate (L), as will be described later. After further investigation, the inventors of the present application found that by having a case with a shape that generates a spring force, the plate-shaped portion can effectively press against the main surface. The present disclosure is based on this new finding.

[0018] The curved portion of the plate-shaped portion (B) may be a curved portion (curved portion) that is curved in an arched shape so as to have a convex shape toward the inside of the case. By using a curved portion that is curved in an arched shape, it becomes easier to apply pressure more evenly to the two main surfaces of the laminate (L). The entire or almost the entire plate-shaped portion (B) may be a curved portion (curved portion). For example, 60% or more or 80% or more of the entire area of the plate-shaped portion (B) may be a curved portion (curved portion).

[0019] In the unhoused state, the bent portion may extend in a ridge shape having a convex shape toward the inside of the case. Stretch The curved part is ridged along the direction of the Stretch It may be ridged. Stretch The curved part is ridged. Stretch The curved portion may be a curved portion.

[0020] In the non-stored state, at least one plate-shaped portion (plate-shaped portion (B)) may include a curved portion extending in a ridge-like shape having a convex shape toward the inside of the case, and two flat portions extending to sandwich the curved portion.

[0021] In the unhoused state, the spring portions present in each of the two regions of the case connecting the two plate-shaped portions may be curved so as to have a convex shape facing the inside or outside of the case. When the spring portions are curved so as to have a convex shape facing the inside of the case, it is possible to make the pressure applied by the plate-shaped portions particularly uniform.

[0022] The spring part has a ridged shape that is convex toward the inside or outside of the case. Stretch The spring portion may be bent or bowed (i.e., curved).

[0023] At least one plate-shaped portion (plate-shaped portion (B)) in the accommodated state may be flatter than the plate-shaped portion (B) in the unaccommodated state, and the spring portion in the accommodated state may be flatter than the spring portion in the unaccommodated state. With this configuration, the plate-shaped portion (B) can particularly effectively apply pressure to the main surface of the laminate (L).

[0024] The case may be a cylindrical body including two plate-shaped portions and the above-mentioned two regions. Unless inconsistent, in this specification, the case may be read as a cylindrical body. Hereinafter, the portions of the case that exist in the two regions connecting the two plate-shaped portions may be referred to as "side wall portions." Also, below, the boundary between the side wall portions and the plate-shaped portions may be referred to as a corner portion.

[0025] Note that one side wall portion does not have to be continuous. For example, one side wall portion may be made up of multiple spring portions connecting two plate-shaped portions. Slit-shaped gaps may exist between the multiple spring portions.

[0026] As described above, the case has a shape that generates a spring force. That is, when the side wall portion expands or contracts along the direction MD, it generates a force that tries to return to its original shape. Specifically, the side wall portion is curved so that when it expands along the direction MD, it generates a force that contracts along the direction MD, and when it contracts along the direction MD, it generates a force that stretches along the direction MD.

[0027] In one example, a cross section of the boundary between the two plate-shaped portions and the two regions (side wall portions) perpendicular to the direction in which the central axis of the cylindrical body (case) extends does not include an acute angle. In other words, the corners between the plate-shaped portions and the side wall portions may be rounded. Alternatively, the corners may not be rounded.

[0028] Each of the two plate-shaped portions may include the curved portion. With this configuration, the main surface of the laminate (L) can be pressed more effectively.

[0029] The positive electrode layer, the negative electrode layer, and the solid electrolyte layer may each be formed by pressure molding a material that does not contain a liquid component. A solid-state battery including a power generating element formed in this manner can be used without applying high pressure to the power generating element (laminate (L)) without significantly reducing performance compared to when the power generating element is applied with high pressure. Therefore, the battery can be used by applying pressure only from the case without applying pressure from outside the battery.

[0030] The contained object (Z) may be composed of only the laminate (L), or may include other components. For example, the contained object (Z) may further include a bag-shaped package formed of a laminate film. In this case, the laminate (L) is contained in the case while sealed in the package.

[0031] The package may include a joint where a part of the laminate film is joined to another part to form a bag-shaped package. The joint may include a laminate part that is laminated on the laminate (L) so as to be located on at least one main surface selected from the two main surfaces of the laminate (L). The package (and the arrangement of the joint) may use the package (and the arrangement of the joint) of the solid-state battery (S2) described below. Therefore, a duplicated description will be omitted.

[0032] The laminate (L) may include a side surface connecting the two main surfaces. The laminate (L) may include two side surfaces connecting the two main surfaces and facing each other. The two spring portions (two side wall portions) of the case may face the two side surfaces of the laminate (L). The side surfaces of the laminate (L) are usually perpendicular to the main surfaces, but do not have to be perpendicular to the main surfaces. The side surfaces are usually flat, but may have steps. For example, the side surfaces may have steps formed by the layers constituting the laminate (L).

[0033] An example of the shape of the main surface of the laminate (L) is rectangular, and the laminate (L) may be rectangular. Alternatively, the shape of the main surface of the laminate (L) may be a shape other than rectangular. For example, the shape of the main surface of the laminate (L) may be trapezoid, may include a circular arc, or may be circular. When the laminate (L) includes two opposing side surfaces, the two side surfaces may or may not be parallel to each other. The side surfaces of the laminate (L) may include curved surfaces.

[0034] When the case is a cylindrical body, the height at a predetermined position of the internal space of the cylindrical body is defined as height H0. Height H0 is the height of the internal space of the cylindrical body when the cylindrical body does not contain an object (Z) and is the longest distance between two adjacent corner portions in the direction MD connecting the two plate-shaped portions. Furthermore, height H1 is the height of the internal space of the cylindrical body when the cylindrical body contains an object (Z) and is the longest distance between two adjacent corner portions in the direction MD connecting the two plate-shaped portions. Furthermore, height Hz is the predetermined height of the object (Z). Height Hz is the height in the direction MD of the object (Z) when not contained in the cylindrical body and is the maximum height on the side surface facing the side wall of the cylindrical body.

[0035] The solid-state battery (S1) may satisfy the following condition (K1), and may further satisfy the conditions (K2) and / or (K3). (K1) Height H1 is greater than height H0. (K2) The height H0 is equal to or less than the height Hz. The height H0 may be smaller than the height Hz. (K3) The height H1 is equal to or greater than the height Hz. The height H1 may be greater than the height Hz.

[0036] The solid-state battery (S1) is H0 <Hz≦H1、H0≦Hz

[0037] (Second solid-state battery (S2)) ​The solid-state battery (S2) includes a contained object and a case that contains the contained object. The contained object includes a laminate including a power generating element and a package in which the laminate is enclosed. The power generating element 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. As described above, the laminate and the contained object may be referred to as the "laminate (L)" and the "contained object (Z)," respectively. The matters regarding the laminate (L) and the contained object (Z) described for the solid-state battery (S1) are also applicable to the solid-state battery (S2), and therefore, redundant explanations may be omitted.

[0038] The package is a bag-shaped package made of a laminate film. The package includes a joint where one part of the laminate film is joined to another part to form the bag-shaped package. The joint may be referred to as a "joint (P)" below. The laminate (L) includes two opposing main surfaces. The joint (P) includes a laminate part that is laminated on the laminate (L) so as to be located on at least one main surface selected from the two main surfaces of the laminate (L). The laminate part (L) is then pressurized by the case.

[0039] In this specification, a configuration in which one element A is stacked on another element B includes a configuration in which element A is placed on element B without any other member in between, as well as a configuration in which element A is placed on element B with another member in between.

[0040] It is known that the characteristics of a solid-state battery can be improved by applying pressure to the power generating element (laminate (L)) in the stacking direction during use. Conventionally, the power generating element of a solid-state battery has been enclosed in a package, which is then housed in a case. In conventional solid-state batteries, efforts have been made to minimize the area of the joints (P) in order to increase the utilization rate of the space inside the case. In conventional solid-state batteries, the joints (P) have been arranged, for example, on the side surfaces of the laminate (L).

[0041] In contrast, in the solid-state battery (S2), a laminated portion, which is at least a part of the joint (P), is placed on the main surface of the laminated body (L), and the laminated portion is pressed by a case. The laminated portion has two or more layers (e.g., three layers) of laminated film stacked therein. In the solid-state battery (S2), the power generating element can be efficiently pressed by the case. Because the laminated body (L) is hard, when the laminated body (L) is pressed by the case, the pressure tends to concentrate on a part of the laminated body (L). In contrast, when the laminated body (L) is pressed via the laminated portion, the elasticity of the two or more layers of laminated film makes it possible to apply the pressure more evenly to the laminated body (L). Furthermore, by placing the laminated portion in a location where the pressure from the case is insufficient, the pressure in that location can be increased. Therefore, the solid-state battery (S2) can be used in a state where it exhibits high performance.

[0042] The joint (P) may be formed by heat-sealing a resin layer present on the surface of the laminate film. The heat-sealing conditions may be adjusted appropriately depending on the type of resin layer. Specifically, heat-sealing may be performed under conditions used in known heat sealing. For example, heat-sealing may be performed at a temperature in the range of 60 to 300°C. The heat-sealing conditions may be selected depending on the material of the laminate film, etc.

[0043] The laminated portion of the joint (P) may be laminated on the laminate (L) so as to be located above the center of at least one main surface of the laminate (L). When the main surface of the laminate (L) is pressed with the plate-shaped portion of the case, the plate-shaped portion bends, and the force pressing on the center of the main surface tends to be weak. Even in such cases, the uniformity of the force pressing on the main surface of the laminate (L) can be increased by arranging the laminated portion above the center of the main surface. When the laminate (L) has two opposing side surfaces, the laminated portion may be laminated on the laminate (L) so as to be located above the center between the two side surfaces of the main surface of the laminate (L).

[0044] When the laminate (L) has two opposing side surfaces, the joint (P) may include a first joint and a second joint formed along the two side surfaces of the laminate (L). In this case, at least a portion of the first joint and at least a portion of the second joint may be laminated on the laminate (L).

[0045] The positive electrode layer, the negative electrode layer, and the solid electrolyte layer may each be a layer formed by pressure molding a material that does not contain a liquid component.

[0046] The planar area X2 of the laminate portion laminated on the main surface of the laminate (L) may be 10% or more, 30% or more, 50% or more, 70% or more, 90% or more, or 100% or more of the area X1 of one main surface of the laminate (L). The area X2 may be 100% or less, or 90% or less of the area X1. For example, the area X2 may be in the range of 10 to 100% or 10 to 90% of the area X1. The laminate portion may be laminated on both of the two main surfaces of the laminate (L). In this case, the area X2 may be greater than 100% of the area X1. By setting the area X2 to 50% or more (e.g., 70% or more) of the area X1, it is possible to apply pressure to the main surface of the laminate (L) more uniformly.

[0047] The joint (P) may include a first joint and a second joint formed along the two side surfaces of the laminate (L). In this case, at least a part of the first joint and at least a part of the second joint may be laminated on the laminate (L).

[0048] The first and second bonding portions may be bonding portions formed by bonding one laminate film that has been drawn to have a recess in which at least a part of the laminate (L) is to be placed to another laminate film. The other laminate film may be a flat laminate film, or may be a laminate film that has been drawn to have a recess in which at least a part of the laminate (L) is to be placed.

[0049] The solid-state battery (S1) and the solid-state battery (S2) can preferably apply pressure to the power generating element using the case. Therefore, the characteristics of the solid-state battery including the power generating element, whose characteristics are improved by pressure, can be improved. In addition to the pressure applied by the case, the solid-state battery (S1) and the solid-state battery (S2) may be pressurized from outside the case using a pressure mechanism (e.g., a pressure device).

[0050] (Components of solid-state batteries (S1) and (S2)) Examples of components of the solid-state batteries (S1) and (S2) of this embodiment 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 battery (particularly an all-solid-state lithium-ion battery), but other solid-state batteries may also be used.

[0051] Each of the solid-state batteries (S1) and (S2) includes a laminate (L) including at least one power-generating element. The laminate (L) may include a plurality of stacked power-generating elements. The laminate (L) may include two current collectors (a positive electrode current collector and a negative electrode current collector) arranged on either side of the power-generating element.

[0052] (case) As described above, the case used for the solid-state battery (S1) has a specific structure. The case for the solid-state battery (S2) is not limited, and a known case used for solid-state batteries may be used. For example, the case for the solid-state battery (S2) may be a metallic cylindrical body, and may be a cylindrical body with a rectangular cross section. Alternatively, the case for the solid-state battery (S2) may have only two plate-shaped portions having the same shape as the plate-shaped portions of the solid-state battery (S1), and the two side wall portions may be flat plate-shaped. Alternatively, the case for the solid-state battery (S2) may be the case used for the solid-state battery (S1). By using the case for the solid-state battery (S1) as the case for the solid-state battery (S2), the laminate (L) can be particularly preferably pressurized.

[0053] From the viewpoint of enhancing the pressurizing property, it is preferable to use a metal plate used for a leaf spring as the metal plate constituting the case (e.g., cylindrical body). Examples of the metal plate constituting the case include a stainless steel plate, a carbon steel plate, an aluminum alloy plate, etc.

[0054] The thickness of the metal plate constituting the case (e.g., cylindrical body) may be selected depending on the material, the required pressurization property, and the material of the metal plate. However, if the metal plate is too thin, the pressurization property will decrease. The thickness of the metal plate constituting the case 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. From the viewpoint of pressurization property, the thickness of the metal plate is preferably 0.20 mm or more.

[0055] When the case is a cylindrical body, the cylindrical body may be formed from a single metal plate. For example, a single metal plate may be formed into a cylindrical shape and two ends may be welded together. Alternatively, the cylindrical body may be formed by joining multiple metal plates by welding or the like. There are no particular limitations on the method for forming the cylindrical body, and it may be formed by a known metal processing method such as drawing.

[0056] There is no limitation on the method for forming the case of the solid-state battery (S2), and it may be formed by the method described for the case of the solid-state battery (S1), or by a known metal processing method.

[0057] When the case is a cylindrical body, the openings at both ends of the cylindrical body are sealed as necessary. There is no limitation on the material for sealing the openings, and metal or resin may be used. When sealing the openings with a metal plate, the openings may be sealed by welding or the like after the object to be contained (Z) is housed in the cylindrical body. However, in the case of a solid-state battery (S1), the openings are sealed so as to maintain the shape that generates the spring force.

[0058] (package) The package is formed using a laminate film. The laminate film is a film formed of multiple layers. As the laminate film, a known laminate film that suppresses the permeation of gases and the like (gas, moisture, etc.) and is capable of heat sealing may be used. The package is preferably formed to be airtight.

[0059] To prevent permeation of gases and the like, the laminate film preferably includes a metal layer (e.g., an aluminum layer). The laminate film typically includes a heat-sealable resin layer on one or both surfaces. Examples of such resin layers include polyolefin resins such as polyethylene. The laminate film may include layers other than these layers, such as a protective layer to improve mechanical strength. The thickness of the laminate film may be in the range of 0.05 mm to 0.50 mm (e.g., 0.10 mm to 0.30 mm).

[0060] (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 used in the positive electrode layer of solid-state batteries. From the viewpoint of increasing 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).

[0061] As the positive electrode active material, any material that can be used as a positive electrode active material for a solid-state battery can be used without any particular limitation. 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 0.05Examples of compounds other than oxides include olivine compounds (LiMPO4) and sulfur-containing compounds (Li2S, 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.

[0062] When a powdered positive electrode active material is used, the average particle size of the positive electrode active material may be, for example, 3 μm or more or 4 μm or more, and 15 μm or less or 11 μm or less. In this specification, the average particle size is the median diameter (D50) in a volume-based particle size distribution measured using a laser diffraction particle size distribution analyzer.

[0063] (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 used in the negative electrode layer of 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).

[0064] The negative electrode active material can be any material that can be used as a negative electrode active material for solid-state batteries, without any particular limitations. In the case of all-solid-state lithium-ion batteries, the negative electrode active material can 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.

[0065] When a powdered negative electrode active material is used, the average particle size of the negative electrode active material may be, for example, 3 μm or more or 4 μm or more, and 50 μm or less or 30 μm or less.

[0066] (solid electrolyte layer) The solid electrolyte layer interposed between the positive electrode and the negative electrode contains a solid electrolyte that conducts charge carriers. The solid electrolyte is usually used in the form of particles (powder).

[0067] The solid electrolyte can be any material that can be used as a solid electrolyte in a 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).

[0068] 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.

[0069] (Positive electrode current collector) A positive electrode current collector is usually disposed on the outside of the positive electrode layer of the power generating element. 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. Leads are connected to the positive electrode current collector and the negative electrode current collector as needed.

[0070] (Negative electrode current collector) A negative electrode current collector is usually disposed on the outside of the negative electrode layer of the power generating element. 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.

[0071] (Method for manufacturing solid state batteries (S1) and (S2)) An example of a manufacturing method for the solid state batteries (S1) and (S2) will be described. Note that the manufacturing method below is just an example, and the solid state batteries (S1) and (S2) may be manufactured by other manufacturing methods. The matters described for the solid state batteries (S1) and (S2) can be applied to the manufacturing method below, so duplicated explanations will be omitted. Furthermore, the matters described in the manufacturing method below may be applied to the above embodiment.

[0072] This example of the manufacturing method includes steps (i), (ii), and (iii). However, when manufacturing a solid-state battery (S1), step (ii) is an optional step. These steps are described below.

[0073] Step (i) is a step of forming the laminate (L). There are no particular limitations on the method of forming the laminate (L), and it may be formed by a known forming method. The power generating element is preferably formed using a material that does not contain a liquid component. An example of a method of forming the laminate (L) that includes a step of forming the power generating element by such a forming method (dry forming method) will be described below.

[0074] In one example of step (i), 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. The stacked materials and metal foil are then pressed together (main press) to form a laminate (L). This main press integrates the metal foil and each layer to obtain the laminate (L). The pressure of the main press can be adjusted appropriately depending on the material and thickness, and may be 50 MPa to 5000 MPa (e.g., 300 MPa to 3000 MPa). In this manner, a laminate (L) having a structure of metal foil (positive electrode current collector) / positive electrode layer / solid electrolyte layer / negative electrode layer / negative electrode current collector or metal foil (negative electrode current collector) / negative electrode layer / solid electrolyte layer / positive electrode layer / positive electrode current collector is obtained. The laminate (L) may also include layers other than these layers, such as thin conductive layers.

[0075] 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.

[0076] By forming a power generating element using a process of pressing a material that does not contain a liquid component, it is possible to obtain a solid-state battery (e.g., an all-solid-state battery) that exhibits high performance without high pressure.Methods for arranging a material that does not contain a liquid component (dispersion medium) in layers include electrostatic spraying, squeegee film formation, and electrostatic painting.

[0077] When the laminate (L) includes multiple power-generating elements, a laminate including one power-generating element may be formed by press molding, and then these laminates may be stacked to form the laminate (L). Alternatively, the laminate (L) may be formed by press molding the materials so that multiple power-generating elements are stacked.

[0078] Step (ii) is a step of sealing the laminate (L) in a bag-shaped package. When producing a solid-state battery (S1), step (ii) may or may not be performed. In step (ii), as will be described in the embodiment described later, the solid-state battery is sealed by heat-sealing a portion of the laminate film. At this time, the inside of the package may be reduced in pressure. For example, the solid-state battery may be sealed in the package in a reduced-pressure chamber. Alternatively, the solid-state battery may be placed in a bag-shaped body formed of the laminate film, and then the inside of the bag-shaped body may be reduced in pressure, and then the final heat-sealing may be performed.

[0079] Step (iii) is a step of housing the package in which the laminate (L) is sealed in a case (e.g., a cylindrical body). At this time, the package is housed in the case with the opening of the case widened as necessary (e.g., with the gap between the two plate-shaped parts widened). After the package is housed in the case, the opening of the case is sealed as necessary. When producing a solid-state battery (S1), the laminate (L) that is not housed in a package may be housed in the case. In this manner, a solid-state battery is produced.

[0080] Examples of embodiments according to the present disclosure will be described below with reference to the drawings. The solid-state battery described below may be modified based on the above description. Among the components of the solid-state battery described below, components that are not essential to the solid-state battery of the present disclosure may be omitted. 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 to make the figures easier to see. Furthermore, in the following figures, cross sections of the case and laminate film (package) may be shown with lines. In the following embodiments, a case in which the contained object includes one power-generating element will be described, but the contained object may also include multiple stacked power-generating elements. In the following embodiments, an example in which the case is cylindrical and the planar shape of the laminate (L) is rectangular will be described, but embodiments according to the present disclosure are not limited to the following example.

[0081] (Embodiment 1) In embodiment 1, an example of a solid state battery (S1) will be described. In embodiment 1, a case where the laminate (L) is sealed in a package will be described, but the laminate (L) does not have to be sealed in a package.

[0082] A perspective view of a solid-state battery 100 of embodiment 1 is shown in Fig. 1, and a cross-sectional view of the solid-state battery 100 is shown in Fig. 2A. The solid-state battery 100 includes an object to be contained 101 and a metal cylindrical body 130 (case) that contains the object to be contained 101. The object to be contained 101 includes a laminate 110 and a package 120 in which the laminate 110 is sealed. Note that the solid-state battery 100 includes a positive electrode lead connected to the positive electrode current collector and a negative electrode lead connected to the negative electrode current collector, but these leads are not shown in Fig. 1.

[0083] In the following, the state in which the cylindrical body 130 contains the object to be contained 101 may be referred to as the "contained state," and the state in which the cylindrical body does not contain the object to be contained 101 may be referred to as the "non-contained state."

[0084] 2A, the laminate 110 includes a positive electrode current collector 111, a power generating element 112, and a negative electrode current collector 115. The power generating element 112 includes a positive electrode layer 112a, a solid electrolyte layer 112b, and a negative electrode layer 112c.

[0085] The laminate 110 includes two opposing main surfaces 110m and two side surfaces 110s connecting the two main surfaces 110m. The two side surfaces 110s face each other. The two main surfaces 110m are surfaces of the surface of the laminate 110 that are present at both ends of each layer in the stacking direction SD. The cylindrical body 130 includes two plate-like portions 130m facing the two main surfaces 110m and two regions (side wall portions 130s) connecting the two plate-like portions 130m. The side wall portions 130s face the side surfaces 110s and include spring portions 130sc.

[0086] Hereinafter, the boundary between the plate-shaped portion 130m and the side wall portion 130s may be referred to as the corner portion 130c. The cross-sectional view of Fig. 2A is a cross-sectional view taken along a direction perpendicular to the direction CD in which the central axis of the cylindrical body 130 extends (or the direction in which the corner portion 130c extends, see Fig. 1). In Fig. 2A, the direction MD connecting the two plate-shaped portions 130m is indicated by an arrow. The direction MD is parallel to the stacking direction SD.

[0087] FIG. 2B shows a cross-sectional view of the cylindrical body 130 in a state where the object 101 is not housed (unhoused state). FIG. 2C shows a cross-sectional view of the cylindrical body 130 in a state where the object 101 is housed (housed state). In FIGS. 2B and 2C, the outline of the laminate 110 and the outline of the object 101 (the outline of the package 120) are indicated by dotted lines. As shown in FIG. 2B, in the unhoused state, each of the two plate-shaped portions 130m includes a curved portion 130mc (curved portion) having a convex shape toward the inside of the cylindrical body 130. Furthermore, in the unhoused state, each of the two side wall portions 130s is curved so as to generate a spring force along a direction connecting the two plate-shaped portions 130m. In an example shown in the first embodiment, in the unhoused state, each of the two side wall portions 130s includes a spring portion 130sc having a convex shape toward the inside of the cylindrical body 130. 2B shows an example in which spring portion 130sc is curved to have a convex shape toward the inside of cylindrical body 130. Note that in the housed state, curved portion 130mc and / or spring portion 130sc may be flat.

[0088] In the illustrated cylindrical body 130, the central portion of the plate-shaped portion 130m that is equidistant from the two corner portions 130c on both sides of the plate-shaped portion 130m is part of the bent portion 130mc. Also, the central portion of the side wall portion 130s that is equidistant from the two corner portions 130c on both sides of the side wall portion 130s is part of the spring portion 130sc.

[0089] As shown in Fig. 2A, in the accommodated state, the two main surfaces 110m of the laminate 110 are pressed by the two bent portions 130mc. In the example shown in Fig. 2A, a package 120 is present between the bent portions 130mc and the laminate 110, but even in this case, the main surfaces 110m are still pressed by the bent portions 130mc. More specifically, the main surfaces 110m are pressed by the bent portions 130mc via the package 120.

[0090] 2B, in the unaccommodated state, the minimum height of the internal space of the cylindrical body 130 (the shortest distance between the two bent portions 130mc) is smaller than the height of the object 101 (the package 120 including the laminate 110) accommodated in the cylindrical body 130. Therefore, the power generating element 112 accommodated in the cylindrical body 130 is pressurized by the two plate-shaped portions 130m (the two bent portions 130mc). The minimum height of the internal space may be smaller than the height of the laminate 110.

[0091] FIG. 2B shows the heights H0 and Hz. FIG. 2C shows the height H1. The height H0 is the height of the internal space of the cylindrical body 130 in the unaccommodated state, and is the maximum height between two adjacent corner portions 130c in the direction MD connecting the two plate-like portions 130m. The two corner portions 130c are two corner portions 130c that sandwich one side wall portion 130s. The height H1 is the height of the internal space of the cylindrical body 130 in the accommodated state, and is the maximum height between two adjacent corner portions 130c in the direction MD connecting the two plate-like portions 130m. The height Hz is the height of the object 101 in the direction MD when not accommodated in the cylindrical body 130, and is the maximum height of the side surface of the cylindrical body 130 facing the side wall portion 130s. The heights H0, H1, and Hz may satisfy the above-mentioned relationship.

[0092] 2A to 2C, in the unhoused state, each of the curved portion 130mc and the spring portion 130sc has a ridge-like shape that protrudes toward the inside of the cylindrical body 130. The ridge-like shape extends along the direction CD in which the central axis of the cylindrical body 130 extends.

[0093] The curved portion 130mc in the accommodated state is less curved and flatter than the curved portion 130mc in the non-accommodated state. On the other hand, the side wall portion 130s (spring portion 130sc) in the accommodated state is less curved and flatter than the side wall portion 130s (spring portion 130sc) in the non-accommodated state. The side wall portion 130s, which has stretched due to accommodating the object 101, generates a force that tries to return to its original shape. It is believed that the presence of the side wall portion 130s that functions as a spring makes it possible to apply pressure to the stack 110 more uniformly.

[0094] On the other hand, an example of a case where a cylindrical body 1 is used in which the side wall portion 130s is flat and not curved when not stored is shown in Fig. 3. In this case, as shown in Fig. 3, pressure from the curved portion 130mc is concentrated on the end portion. As a result, the uniformity of pressure applied to the stack 110 is significantly reduced.

[0095] Although FIG. 1 shows an example in which the cross section of the corner portion 130c in the uncontained state (a cross section perpendicular to the direction in which the corner portion 130c extends) includes an acute angle, the shape of the cross section may be other shapes. For example, the cross section may be an arc shape. Although FIG. 1 shows an example in which the corner portion 130c is not rounded, the corner portion 130c may be rounded. In other words, the corner portion 130c may be formed with a curved surface. Cross-sectional views of an example of a cylindrical body 130 having such a corner portion 130c are shown in FIGS. 4 and 5. The curved portion 130mc and the spring portion 130sc shown in FIGS. 4 and 5 have shapes similar to those described with reference to FIGS. 2A to 2C, respectively.

[0096] The corner portions 130c of the cylindrical body 130 in Figures 4 and 5 are formed by curved surfaces. The plate-like portion 130m in Figure 5 includes a curved portion 130mc and flat portions 130mf connected to both sides of the curved portion 130mc. The flat portions 130mf are flat and extend along the direction CD (see Figure 1). Note that, similar to the plate-like portion 130m shown in Figure 5, the side wall portion 130s may also include two flat portions extending to sandwich the spring portion 130sc.

[0097] The size of the cylindrical body 130 in FIG. 4 when the object 101 is not housed will be described with reference to FIG. 6. Rectangle 130v is a rectangle that contacts the outside of the cylindrical body 130, and the four sides of rectangle 130v correspond to plate-like portion 130m and side wall portion 130s of the cylindrical body 130. The width W and height H of the outer shape of the cylindrical body 130 are represented by the width and height of rectangle 130v, respectively. FIG. 6 shows the depth mch of bent portion 130mc and the depth sch of spring portion 130sc. These depths are represented by the distance from rectangle 130v. If the plate thickness of the cylindrical body 130 is d, the narrowest width of the width of the internal space of the cylindrical body 130 is represented by (W - 2sch - 2d). The shortest height of the internal space of the cylindrical body 130 is represented by (H - 2mch - 2d). The minimum height of the internal space of the cylindrical body 130 is smaller than the height of the object 101 to be contained inside the cylindrical body 130. The width of the internal space of the cylindrical body 130 is set to a width that allows the object 101 to be contained inside the cylindrical body 130.

[0098] The total depth mch of the two bent portions 130mc may be equal to or less than the height H of the outer shape of the cylindrical body 130 (more specifically, equal to or less than the height H minus the thickness of the two bent portions 130mc). That is, in the uncontained state, the two first curved portions may be in contact with each other. One depth mch may be equal to or less than 0.5H (equal to or less than 0.5 times the height H), 0.4H or less, or 0.3H or less. One depth mch may be equal to or greater than 0.05H, 0.1H or more, or 0.2H or more. One depth mch may be in the range of 1.0 mm to 10 mm, 1.0 mm to 5.0 mm, 2.0 mm to 10 mm, or 2.0 mm to 5.0 mm.

[0099] The depth sch of one spring portion 130sc may be 0.3 times or less (i.e., 0.3W or less) of the width W of the outer shape of the cylindrical body 130. One depth sch may be 0.2W or less, or 0.1W or less. One depth sch may be 0.01W or more, 0.05W or more, or 0.1W or more. One depth sch may be in the range of 0.5 to 5.0 mm, or in the range of 1.0 mm to 5.0 mm.

[0100] FIG. 6 shows the maximum interval G0. The maximum interval G0 is the interval between two plate-like portions 130m in the non-accommodated state and is the maximum interval in the direction MD. As shown in FIG. 6, the maximum interval G0 is usually the interval at the position of the end portion (near the boundary between the plate-like portion 130m and the side wall portion 130s) of the bent portion 130mc having a convex shape toward the inside of the cylindrical body 130. The maximum interval G1 (not shown) may be larger than the maximum interval G0. The maximum interval G1 is the interval between two plate-like portions 130m in the accommodated state and is the maximum interval in the direction MD. By satisfying G0 < G1, the main surface 110m can be effectively pressed. In the case of the cylindrical body 130 shown in FIGS. 2B and 2C, it is possible to consider G0 = H0 and G1 = H1.

[0101] In the above conditions (K1) to (K3), the height H0 may be replaced with the maximum interval G0, and the height H1 may be replaced with the maximum interval G1. The solid battery (S1) may satisfy G0 < Hz ≦ G1, G0 ≦ Hz < G1, or G0 < Hz < G1. By satisfying any of these formulas, it may be easier to effectively press the main surface 110m. However, the solid battery (S1) does not necessarily have to satisfy these formulas.

[0102] An experiment was conducted in which a package 120 containing a laminate 110 was housed in a cylindrical body 1 having the shape shown in FIG. 3. As described above, the cylindrical body 1 shown in FIG. 3 is a cylindrical body in which the side wall portion 130s of the cylindrical body 130 shown in FIG. 1 is flat. Pressure-sensitive paper was sandwiched between the plate-like portion 130m and the package 120, and the color change was observed. FIG. 7 shows the pressure-sensitive paper discolored by pressure. The darkened areas are areas where high pressure was applied. The dotted line in FIG. 7 indicates the position of the outer shape of the package 120. As shown in FIG. 7, when the cylindrical body 1 shown in FIG. 3 was used, the pressure was concentrated on the outer edge of the package 120. Therefore, it is believed that the pressure applied to the power-generating element 112 was also concentrated on the outer edge of the power-generating element 112.

[0103] Furthermore, a similar experiment was conducted using a cylindrical body 130 having a shape similar to that shown in Fig. 4. The pressure-sensitive paper used in this experiment is shown in Fig. 8. As shown in Fig. 8, in this case, the entire package 120 was pressurized almost uniformly. Therefore, it is believed that the power generating element 112 was also pressurized almost uniformly.

[0104] Furthermore, a solid battery SC1 using the cylindrical body 1 shown in FIG. 3 and a solid battery SA1 using a cylindrical body 130 having the same shape as that shown in FIG. 4 were fabricated. The solid batteries SC1 and SA1 had the same configuration except for the cylindrical body. The solid batteries SC1 and SA1 were subjected to a test at 110°C, 1×10 -2 The solid battery A1 was subjected to 300 charge-discharge cycles at a current of 1 C under an atmosphere of 2 Pa. The capacity retention rate at 300 cycles was 82.0% for the solid battery SC1, while it was 93.5% for the solid battery A1, which was excellent. The capacity retention rate is the ratio of the discharge capacity when the initial discharge capacity is taken as 100%.

[0105] (Embodiment 2) In embodiment 2, an example of a solid state battery (S2) will be described. A cross section of a solid state battery 200 of embodiment 2 is shown typically in Fig. 9. In addition, a cross section of a laminate 110 in Fig. 9 is shown typically in Fig. 10.

[0106] The solid-state battery 200 of the second embodiment includes an object to be contained 101 and a metal cylindrical body 130 (case) that contains the object to be contained 101. The object to be contained 101 includes a stacked body 110 and a package 120 in which the stacked body 110 is sealed.

[0107] The package 120 is a bag-shaped package made of a laminate film. The package 120 includes a joint 120P where one part of the laminate film is joined to another part to form the bag-shaped package 120. The laminate 110 includes two opposing main surfaces 110m and two opposing side surfaces 110s connecting the two main surfaces 110m. The joint 120P includes a laminate portion 120L that is laminated on the laminate 110 so as to be located on the main surfaces 110m. In the cross-sectional view of FIG. 9, the portion of the joint 120P forms the laminate portion 120L as it is. The laminate portion 120L is pressurized by a cylindrical body 130 (case). In FIG. 9, the direction MD connecting the two plate-like portions 130m is indicated by an arrow.

[0108] The cylindrical body 130 includes two plate-like portions 130m facing the two main surfaces 110m, and two regions (side wall portions 130s) connecting the two plate-like portions 130m. The side wall portions 130s face the side surfaces 110s.

[0109] Referring to FIG. 10, the laminate 110 includes a positive electrode current collector 111, a power generating element 112, and a negative electrode current collector 115. The power generating element 112 includes a positive electrode layer 112a, a solid electrolyte layer 112b, and a negative electrode layer 112c. These layers are stacked along a stacking direction SD. In FIG. 10, the stacking direction SD of each layer of the laminate 110 is indicated by an arrow. The direction MD in FIG. 9 is parallel to the stacking direction SD in FIG. 10.

[0110] FIG. 11 shows a plan view of a portion of the package 120 as viewed from above. FIG. 11 also shows the arrangement of the laminate 110. In FIG. 11, the region of the laminate 120L is indicated by hatching. As shown in FIG. 11, the laminate 120L is laminated on the laminate 110 so as to be located above the center portion between at least two side surfaces 110s of the main surface 110m. The laminate 120L extends along the direction CD in which the central axis of the cylindrical body 130 extends (or along the direction in which the corner portions 130c extend).

[0111] 9 shows an example in which a cylindrical body 130 having a rectangular cross section is used as the case. However, there is no particular limitation on the shape of the case, and a case having the shape shown in FIG. 3 or a case used in a solid-state battery (S1) may be used. By using a case used in a solid-state battery (S1), the laminate 110 can be effectively pressurized.

[0112] In the solid-state battery 200, the laminated portion 120L is disposed on the main surface 110m of the laminated body 110. Therefore, the portion of the laminated portion 120L is likely to be pressurized by the cylindrical body 130. If the laminated portion 120L were not present, the pressure from the cylindrical body 130 would tend to be concentrated near the corner portion 130c of the main surface 110m. In contrast, by disposing the laminated portion 120L on the main surface 110m, it is possible to increase the uniformity of the pressure force applied to the main surface 110m.

[0113] Cross-sectional views of other examples of package 120 are shown in Figures 12 to 14. Note that in these figures, gaps are provided between components to make the drawings easier to see, but some of these gaps do not actually exist. For example, in the stacking direction SD, the laminate 110 and package 120 are in contact. In Figures 12 to 14, the portions where the laminate film is heat-sealed are indicated by white dotted lines.

[0114] 12, a joint 120P is formed by heat-sealing the same surfaces of the laminate films that make up the package 120. The joint 120P is folded to form a laminated portion 120L on the main surface 110m of the laminate 110.

[0115] 13 and 14, the joint 120P includes a first joint 120P1 and a second joint 120P2 formed along the two side surfaces 110s. By bending these joints, at least a part of the joints, that is, a stacked portion 120L, is stacked on the main surface 110m of the laminate 110.

[0116] The laminate film constituting the package 120 shown in Figures 12 to 14 includes a heat-sealable resin layer on at least the surface to be heat-sealed. The laminate film constituting the package 120 shown in Figure 9 includes heat-sealable resin layers on both surfaces.

[0117] An example of a method for enclosing the laminate 110 in the package 120 shown in Fig. 12 will be described with reference to Fig. 15A to Fig. 15C. First, the laminate 110 is prepared as shown in Fig. 15A. Fig. 15A also shows a positive electrode lead 141 connected to the positive electrode current collector 111 and a negative electrode lead 142 connected to the negative electrode current collector 115.

[0118] Next, as shown in Fig. 15B, the laminate 110 is housed in a bag-shaped body 151 formed of a laminate film. The bag-shaped body 151 includes a joint 120PP corresponding to the laminated portion 120L shown in Fig. 12, and a joint 120PR formed by joining one side of the bag-shaped body. Note that in Fig. 15B and subsequent figures, the portion where the joint exists may be indicated by hatching.

[0119] Next, as shown in FIG. 15C , the laminate film in the portion where the positive electrode lead 141 and the negative electrode lead 142 are present is heat-sealed via a sealant or the like to form a new joint 120PF. As a result, the laminate 110 is sealed in a package 120 formed of the laminate film. Finally, as necessary, the joint 120PR is folded toward the side where the joint 120PP is present or toward the opposite side. At least a portion of the folded joint 120PR may be laminated on the laminate 110. In this manner, the laminate 110 is sealed in the package 120.

[0120] An example of a method for enclosing the laminate 110 in the package 120 shown in Figures 13 and 14 will be described with reference to Figures 16A and 16B. First, as shown in Figure 16A, a sheet 161 having a recess 161c capable of accommodating the laminate 110 is prepared by drawing or the like.

[0121] Next, the laminate 110 is placed in the recess 161c. Next, a flat laminate sheet having the same size as the sheet 161 is placed on the sheet 161, and the four overlapping sides are heat-sealed. Specifically, as shown in the top view of FIG. 16B, a joint 120PF, a joint 120PR, and two joints 120PP are formed. The joints 120PP are the portions that will become the laminate 120L in FIGS. 13 and 14. The laminate 110 is sealed in a bag-shaped body 151 formed from the laminate film by heat sealing.

[0122] Next, the two joint portions 120PP are folded and stacked on the laminate 110. When forming the package 120 shown in FIG. 13, the joint portions 120PP are folded away from the recessed portion 161c. When forming the package 120 shown in FIG. 14, the joint portions 120PP are folded toward the recessed portion 161c. Before or after folding the joint portions 120PP, the joint portions 120PR are folded as needed. At least a portion of the folded joint portions 120PR may be stacked on the laminate 110. In this way, the laminate 110 is sealed in the package 120.

[0123] Two sheets each having a recess 161c may be stacked together to form the bag-shaped body 151. In the above manufacturing method, when the laminate 110 is sealed in the package 120, the pressure inside the package 120 may be reduced. [Industrial Applicability]

[0124] The present disclosure can be used in solid-state batteries. [Explanation of symbols]

[0125] 100, 200: Solid battery 101: Detainees 110: Laminate 110m: main surface 110s: Side 112: Power generation element 112a: Positive electrode layer 112b: Solid electrolyte layer 112c: Negative electrode layer 120: Package 120L: Laminated section 120P:Joint part 120P1: First joint 120P2: Second joint 130: Cylindrical body (case) 130c: Corner section 130m: Plate section 130mc: Bent section 130mf: Flat part 130s: Side wall part 130sc: Spring part

Claims

1. A solid-state battery, The battery includes an object to be contained, the object including a laminate including a power generating element, and a metal case that contains the object to be contained, the power-generating element 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 includes two opposing main surfaces, the case includes two plate-shaped portions facing each other so as to sandwich the laminate therebetween, and two side wall portions connecting the two plate-shaped portions; each of the two plate-shaped portions includes a curved portion that is curved so as to have a convex shape toward the inside of the case when the case is in an unaccommodated state in which the object is not accommodated; the case has a shape that generates a spring force on the two plate-shaped portions in a direction connecting the two plate-shaped portions, When the case is in a storage state in which the object is stored, the two main surfaces are pressed by the two plate-shaped portions, In the non-stored state, the spring portions present on each of the two side wall portions are curved and extend in a ridge-like shape so as to have a convex shape toward the inside of the case, In the unhoused state, the bent portion extends in a ridge shape having a convex shape toward the inside of the case, The solid-state battery, wherein the case is a cylindrical body including the two plate-shaped portions and the two side wall portions.

2. A solid-state battery as described in claim 1, wherein the four corner portions between the two plate-shaped portions and the two side wall portions are rounded.

3. The solid-state battery according to claim 1 , wherein in the unhoused state, each of the two plate-shaped portions includes the curved portion extending in a ridge shape and two flat portions extending so as to sandwich the curved portion.

4. the plate-shaped portion in the accommodated state is flatter than the plate-shaped portion in the non-accommodated state; The solid-state battery of claim 1 , wherein the spring portion in the accommodated state is flatter than the spring portion in the unaccommodated state.

5. The solid-state battery according to claim 1 , wherein a cross section of the boundary between the two plate-shaped portions and the two side wall portions, which is perpendicular to the direction in which the central axis of the cylindrical body extends, does not include an acute angle.

6. 6. The solid-state battery according to claim 1, wherein the positive electrode layer, the negative electrode layer, and the solid electrolyte layer are each formed by pressure molding a material that does not contain a liquid component.

7. The contained item further includes a bag-shaped package formed of a laminate film, The solid-state battery according to any one of claims 1 to 6, wherein the laminate is housed in the case in a state where it is sealed in the package.

8. the package includes a joint portion where a part of the laminate film is joined to another part to form the bag-shaped package, The solid-state battery according to claim 7 , wherein the joint portion includes a laminate portion laminated on the laminate body so as to be located on at least one principal surface selected from the two principal surfaces.

Images