Solid-state battery and method for producing same

Abstract

The present disclosure improves the reliability of a solid-state battery that uses a ceramic package. A solid-state battery (100) according to the present disclosure comprises a ceramic package (10) and a battery cell element (40). The battery cell element (40) is disposed in a cavity (CA). The ceramic package (10) comprises: a first bottom surface terminal (22) that is provided to an internal bottom surface (20b); and a second bottom surface terminal that is provided to the internal bottom surface (20b) so as to be insulated from the first bottom surface terminal (22). A first electrode layer (41) is in contact with the first bottom surface terminal (22) and a pair of first internal lateral surfaces (20p). A second electrode layer is in contact with the second bottom surface terminal and the pair of first internal lateral surfaces (20p). The battery cell element (40) is constrained by the ceramic package (10) in the width direction.

Description

Solid-state battery and method for manufacturing the same

[0001] The present disclosure relates to a solid-state battery and a method for manufacturing the same.

[0002] As a container for a solid-state battery, use of a ceramic package has been considered. Advantages of using a ceramic package include, for example, high airtightness inside the ceramic package, the ability to surface-mount a solid-state battery on a circuit board together with electronic components, and the ability to impart high heat resistance to the solid-state battery.

[0003] Patent Document 1 describes an all-solid-state battery including an elastic conductive member disposed between an electrode laminate and the inner bottom surface of a sealing body. The elastic conductive member is electrically connected to the conductive path of the concave container. The electrode laminate is pressed toward the inner bottom surface of the concave container by the elastic conductive member.

[0004] Patent Document 2 describes that a positive electrode layer and a negative electrode layer are laminated in a direction in which the base portion of the case body extends. The solid-state battery of Patent Document 2 includes an insulating layer disposed between the battery laminate and a lid portion. Patent Document 2 further describes that bump layers formed of solder may be provided between the positive electrode layer and the positive electrode connection portion and between the negative electrode layer and the negative electrode connection portion, respectively.

[0005] International Publication No. 2024 / 018982 International Publication No. 2012 / 081366

[0006] In view of the reliability of a solid-state battery using a ceramic package, there is room for improvement with respect to the above-described conventional technologies.

[0007] This disclosure comprises: a ceramic package having a cavity formed therein having two pairs of sides parallel to each other when viewed from a first surface in plan view; and a battery element disposed within the cavity and having two pairs of sides parallel to each other when viewed from a plan view, wherein the battery element includes a first electrode layer, a solid electrolyte layer, and a second electrode layer, and the width direction is defined as the direction perpendicular to the stacking direction of the first electrode layer, the solid electrolyte layer, and the second electrode layer and the depth direction of the cavity, the stacking direction and the depth direction are perpendicular to each other; the cavity includes an opening formed on the first surface, an internal bottom surface located opposite to the opening in the depth direction, a pair of first internal sides facing each other in the width direction, and a pair of second internal sides facing each other in the stacking direction; and the ceramic package includes a first bottom terminal provided on the internal bottom surface and a second bottom terminal provided on the internal bottom surface so as to be insulated from the first bottom terminal. The present invention provides a solid-state battery in which the first electrode layer is in contact with the first bottom terminal and the pair of first internal surfaces, and the second electrode layer is in contact with the second bottom terminal and the pair of first internal surfaces, and the battery element is constrained in the width direction by the ceramic package.

[0008] The technology described herein can improve the reliability of solid-state batteries using ceramic packages.

[0009] Figure 1 is a cross-sectional view of the solid-state battery according to Embodiment 1 along line II. Figure 2 is a plan view of the solid-state battery with the cover removed. Figure 3 is a perspective view of the package body. Figure 4 is a perspective view of the battery element. Figure 5 is a manufacturing process diagram of the solid-state battery. Figure 6 is a cross-sectional view of the solid-state battery according to Embodiment 2 along line VI-VI. Figure 7 is a plan view of the solid-state battery with the cover removed. Figure 8 is a perspective view of the package body. Figure 9 is a diagram showing other shapes of the protrusions. Figure 10 is a cross-sectional view of the solid-state battery according to Embodiment 3 along line XX. Figure 11 is a plan view of the solid-state battery with the cover removed. Figure 12 is a perspective view of the package body.

[0010] (Knowledge forming the basis of this disclosure) Solid-state batteries using ceramic packages are surface-mounted onto a circuit board via a solder reflow process along with electronic components. Considering the solder reflow process during surface mounting, it is technically difficult to provide bump layers between the positive electrode layer and the positive electrode connection, and between the negative electrode layer and the negative electrode connection, as in the solid-state battery described in Patent Document 2.

[0011] When considering surface mounting solid-state batteries using ceramic packages onto circuit boards, miniaturization of the solid-state battery is required. However, additional components such as the elastic conductive member described in Patent Document 1 hinder the miniaturization of solid-state batteries. For example, the ceramic package requires both the elastic conductive member and a special structure for fixing the elastic conductive member, which hinders the miniaturization and cost reduction of the solid-state battery. Furthermore, the electrode stack, which is the power generation component of the solid-state battery, tends to have large dimensional variations in the thickness direction, which is the stacking direction. Therefore, high dimensional accuracy and high assembly accuracy are required for the elastic conductive member in order to apply sufficient pressing force to the electrode stack. This increases the difficulty of manufacturing solid-state batteries and causes a decrease in yield during manufacturing.

[0012] In view of the above circumstances, this disclosure provides a technology for fixing a battery element inside a ceramic package using a simple structure and a simple manufacturing method.

[0013] In another aspect, this disclosure provides a technique for improving the reliability of electrical connections between ceramic packages and battery elements through a simple structure and a simple manufacturing method.

[0014] The embodiments of this disclosure will be described below with reference to the drawings. This disclosure is not limited to the embodiments described below.

[0015] (Embodiment 1) Figure 1 is a cross-sectional view of a solid-state battery 100 according to Embodiment 1 along line II. The solid-state battery 100 comprises a ceramic package 10 and a battery element 40. The ceramic package 10 comprises a cavity CA. The battery element 40 is arranged in the cavity CA. The solid-state battery 100 can be surface-mounted to a circuit board by soldering.

[0016] The ceramic package 10 includes a package body 20 and a lid 30. The package body 20 is the portion in which the cavity CA is formed. The lid 30 is bonded to the package body 20 to seal the cavity CA.

[0017] Figure 2 is a plan view of the solid battery 100 with the cover 30 removed. Figure 3 is a perspective view of the package body 20. Figure 4 is a perspective view of the battery element 40.

[0018] As shown in Figure 2, the package body 20 has two pairs of sides that are parallel to each other when viewed from the first surface. The first surface is the top surface of the package body 20. The cavity CA also has two pairs of sides that are parallel to each other when viewed from the top. The battery element 40 also has two pairs of sides that are parallel to each other when viewed from the top. In each of the package body 20, cavity CA, and battery element 40, one pair of sides is perpendicular to the other pair of sides.

[0019] For example, if a ceramic package has two pairs of parallel sides when viewed from above, and a circular cavity is provided in that cavity, and a circular battery element is placed in that cavity, the ratio of the area of ​​the battery element to the area of ​​the ceramic package is small. In other words, the volumetric efficiency and energy density of the solid-state battery are low.

[0020] In contrast, according to this embodiment, a cavity CA having two pairs of parallel sides is provided in a package body 20 having two pairs of parallel sides, and a battery element 40 having two pairs of parallel sides is arranged in the cavity CA. With this configuration, the ratio of the area of ​​the battery element 40 to the area of ​​the ceramic package 10 is large. In other words, according to this embodiment, the volumetric efficiency and energy density of the solid battery 100 can be improved.

[0021] In this disclosure, the shape having two pairs of parallel sides when viewed from above with respect to the outside of the package body 20, the cavity CA side, and the battery element 40 includes both cases where a radius or chamfer is provided at the corner where two adjacent sides of the shape connect, and cases where the corners intersect.

[0022] As shown in Figures 2 and 3, the cavity CA includes an internal bottom surface 20b, a pair of opposing first internal sides 20p, and a pair of opposing second internal sides 20q. The cavity CA includes an opening formed on the first surface (top surface) of the package body 20. In the depth direction of the cavity CA, the internal bottom surface 20b is located on the opposite side of the opening. The ceramic package 10 includes a first bottom terminal 22 and a second bottom terminal 23. The first bottom terminal 22 and the second bottom terminal 23 are terminals provided on the internal bottom surface 20b. Each of the first bottom terminal 22 and the second bottom terminal 23 constitutes a part of the internal bottom surface 20b. The second bottom terminal 23 is insulated from the first bottom terminal 22.

[0023] As shown in Figure 1, the package body 20 includes a via conductor 28 and a first external terminal 29. The first external terminal 29 is provided on the outer bottom surface of the package body 20. The via conductor 28 penetrates the bottom of the package body 20 and extends from the inner bottom surface 20b to the outer bottom surface of the package body 20. The via conductor 28 connects the first bottom terminal 22 and the first external terminal 29. The first external terminal 29 is connected to the circuit board via solder.

[0024] Although not shown in Figure 1, a similar structure is also provided on the side of the second bottom terminal 23. That is, the package body 20 includes a via conductor and a second external terminal. The second external terminal is provided on the external bottom surface of the package body 20. The via conductor penetrates the bottom of the package body 20 and extends from the internal bottom surface 20b to the external bottom surface of the package body 20. The second bottom terminal 23 and the second external terminal are connected by the via conductor. The second external terminal is connected to the circuit board via solder.

[0025] The package body 20 is made of a ceramic material such as alumina ceramic or aluminum nitride ceramic. The first bottom terminal 22, the second bottom terminal 23, the via conductor 28, and the external terminals (first external terminal and second external terminal) are made of a metallic material such as W, Mo, Cu, Ag, Cu alloy, or Ag alloy. The surfaces of the first bottom terminal 22, the second bottom terminal 23, and the external terminals (first external terminal and second external terminal) are plated with Ni and Au. The lid 30 is made of a metallic material with a low coefficient of thermal expansion, such as Kovar. The lid 30 may also be made of an insulating material such as ceramic.

[0026] As shown in Figures 2 and 4, the battery element 40 includes a first electrode layer 41, a solid electrolyte layer 43, and a second electrode layer 42. The first electrode layer 41 is, for example, a positive electrode layer. The second electrode layer 42 is, for example, a negative electrode layer. The direction perpendicular to the stacking direction SD of the first electrode layer 41, the solid electrolyte layer 43, and the second electrode layer 42 is defined as the width direction FD. The stacking direction SD and the width direction FD are perpendicular to the depth direction of the cavity CA. A pair of first internal sides 20p are located in the width direction FD. The depth direction of the cavity CA coincides with the stacking direction of the ceramic green sheet when manufacturing the package body 20. The first electrode layer 41 is in contact with the first bottom terminal 22 and is electrically connected to the first bottom terminal 22. The second electrode layer 42 is in contact with the second bottom terminal 23 and is electrically connected to the second bottom terminal 23. With this configuration, an electrical connection between the battery element 40 and the outside can be established via the ceramic package 10.

[0027] The orientation of the battery element 40 in the cavity CA is determined such that the first electrode layer 41 is in contact with the first bottom terminal 22 and a pair of first internal sides 20p, and the second electrode layer 42 is in contact with the second bottom terminal 23 and a pair of first internal sides 20p. The battery element 40 is constrained by the ceramic package 10 in the width direction FD. That is, the first electrode layer 41 of the battery element 40 is pressed against the pair of first internal sides 20p. The second electrode layer 42 of the battery element 40 is pressed against the pair of first internal sides 20p. The solid electrolyte layer 43 of the battery element 40 is pressed against the pair of first internal sides 20p. In this way, the battery element 40 is fixed to the ceramic package 10. The solid battery 100 can be manufactured by placing the battery element 40 in the cavity CA and then expanding the battery element 40.

[0028] In the solid-state battery 100 of this embodiment, the battery element 40 is fixed to the ceramic package 10 by a restraining force from the ceramic package 10. Therefore, in the solid-state battery 100 of this embodiment, other members such as elastic conductive members for pressing can be omitted, and soldering between the battery element 40 and the ceramic package 10 can also be omitted. This is advantageous for miniaturizing the solid-state battery 100 and reducing costs. According to this embodiment, the battery element 40 can be fixed inside the ceramic package 10 with a simple structure.

[0029] As shown in Figure 3, the first bottom terminal 22 and the second bottom terminal 23 each have a short side and a long side when viewed from the first surface in a plan view. On the internal bottom surface 20b, the first bottom terminal 22 and the second bottom terminal 23 are arranged parallel to each other. The length of the long side of the first bottom terminal 22 and the length of the long side of the second bottom terminal 23 are equal to, for example, the distance between the first internal surface 20p and the first internal surface 20p. The length of the short side of the first bottom terminal 22 may be equal to, shorter than, or longer than the dimension (thickness) of the first electrode layer 41 in the stacking direction SD. Preferably, the length of the short side of the first bottom terminal 22 is equal to or longer than the dimension (thickness) of the first electrode layer 41 in the stacking direction SD. Even if the length of the shorter side of the first bottom terminal 22 is longer than the dimensions of the first electrode layer 41 in the stacking direction SD, the first bottom terminal 22 does not fundamentally overlap with the solid electrolyte layer 43, but it may overlap. The length of the shorter side of the second bottom terminal 23 may be equal to the dimensions (thickness) of the second electrode layer 42 in the stacking direction SD, shorter than it, or longer than it. It is desirable that the length of the shorter side of the second bottom terminal 23 is equal to or longer than the dimensions (thickness) of the second electrode layer 42 in the stacking direction SD. Even if the length of the shorter side of the second bottom terminal 23 is longer than the dimensions of the second electrode layer 42 in the stacking direction SD, the second bottom terminal 23 does not fundamentally overlap with the solid electrolyte layer 43, but it may overlap. The shape and dimensions of the second bottom terminal 23 may be equal to the shape and dimensions of the first bottom terminal 22.

[0030] The first bottom terminal 22 and the second bottom terminal 23 may each have no short side and long side when viewed from the first surface, and their side lengths may be the same. The side lengths of the first bottom terminal 22 and the second bottom terminal 23 in the width direction FD are, for example, equal to the distance between the first internal surface 20p and the first internal surface 20p. The side length of the first bottom terminal 22 in the stacking direction SD may be equal to, shorter than, or longer than the dimension (thickness) of the first electrode layer 41 in the stacking direction SD. It is desirable that the side length of the first bottom terminal 22 in the stacking direction SD be equal to or longer than the dimension (thickness) of the first electrode layer 41 in the stacking direction SD. Even when the side length of the first bottom terminal 22 in the stacking direction SD is longer than the dimension of the first electrode layer 41 in the stacking direction SD, the first bottom terminal 22 does not basically overlap with the solid electrolyte layer 43, but it may overlap. The length of the side of the second bottom terminal 23 in the stacking direction SD is preferably equal to or longer than the dimension (thickness) of the second electrode layer 42 in the stacking direction SD. Even if the length of the side of the second bottom terminal 23 in the stacking direction SD is longer than the dimension of the second electrode layer 42 in the stacking direction SD, the second bottom terminal 23 does not fundamentally overlap with the solid electrolyte layer 43, but it may overlap. The shape and dimensions of the second bottom terminal 23 may be equal to the shape and dimensions of the first bottom terminal 22.

[0031] As shown in Figure 2, the pair of second internal surfaces 20q are positioned in a direction parallel to the stacking direction SD of the battery element 40. In the direction parallel to the stacking direction SD, a gap 34 exists between at least one of the pair of second internal surfaces 20q and the battery element 40. In this embodiment, a gap 34 exists between each of the pair of second internal surfaces 20q and the battery element 40.

[0032] As shown in Figure 4, the battery element 40 has a rectangular parallelepiped shape. Three layers, a first electrode layer 41, a solid electrolyte layer 43, and a second electrode layer 42, are stacked along the stacking direction SD. The dimensional accuracy of the battery element 40 in the width direction FD, which is perpendicular to the stacking direction SD, is higher than the dimensional accuracy of the battery element 40 in the stacking direction SD. This is because the dimensions of the battery element 40 in the width direction FD are controlled with high precision by the dimensions of the molding die. On the other hand, the dimensions of the battery element 40 in the stacking direction SD reflect the thickness variation due to the mass variation of the battery element 40. Therefore, the dimensional variation of the battery element 40 in the stacking direction SD is large. The orientation of the battery element 40 in the cavity CA is determined so that both end faces of the battery element 40 in the width direction FD are in contact with the ceramic package 10. Therefore, the restraining force from the ceramic package 10 can be reliably applied to the battery element 40. Furthermore, since a gap 34 is provided between each of the end faces of the battery element 40 in the stacking direction SD and at least one of the pair of second internal side surfaces 20q, dimensional variations of the battery element 40 in the stacking direction SD can be absorbed by the gap 34.

[0033] In Figure 4, the first electrode layer 41, solid electrolyte layer 43, and second electrode layer 42 of the battery element 40 have the same dimensions (width) in the width direction FD. However, at least one selected from the first electrode layer 41 and the second electrode layer 42 may be larger than the solid electrolyte layer 43 in the width direction FD. With this configuration, it is easier to apply a restraining force from the ceramic package 10 using at least one selected from the first electrode layer 41 and the second electrode layer 42.

[0034] Each of the first electrode layer 41 and the second electrode layer 42 may have a pair of parallel short sides and a pair of parallel long sides when viewed from above in the depth direction of the cavity CA, or the pair of parallel sides and the pair of parallel sides may be of the same length. When there are short sides and long sides, it is desirable that the stacking direction SD is parallel to the short side and the width direction FD is parallel to the long side. In the width direction FD parallel to the long side, at least one selected from the first electrode layer 41, the second electrode layer 42, and the solid electrolyte 43 may be constrained by the ceramic package 10. This is because the change in dimensions when the battery element 40 is expanded is greatest in the width direction FD. Also, in the case of sides of the same length without short sides and long sides, at least one selected from the first electrode layer 41, the second electrode layer 42, and the solid electrolyte 43 may be constrained by the ceramic package 10 in the width direction FD.

[0035] In the battery element 40, if the first electrode layer 41 is the positive electrode layer, the first electrode layer 41 includes materials such as a positive electrode active material, a conductive material, and a solid electrolyte. The first electrode layer 41 may also include a binder. If the second electrode layer 42 is the negative electrode layer, the second electrode layer 42 includes materials such as a negative electrode active material, a conductive material, and a solid electrolyte. The second electrode layer 42 may also include a binder.

[0036] The positive electrode active material may be a material that has the ability to intercept and release metal ions such as lithium ions. Examples of positive electrode active materials include lithium-containing transition metal oxides, lithium-containing transition metal phosphates, transition metal fluorides, polyanionic materials, fluorinated polyanionic materials, transition metal sulfides, transition metal oxysulfides, and transition metal oxynitrides. Examples of lithium-containing transition metal oxides include lithium cobalt oxide, lithium manganese oxide, lithium nickel oxide, lithium nickel cobalt aluminum oxide, lithium nickel cobalt manganese oxide, and lithium nickel manganese oxide. Examples of lithium-containing transition metal phosphates include lithium iron phosphate, lithium vanadium phosphate, lithium cobalt phosphate, and lithium nickel phosphate.

[0037] The negative electrode active material may be a material that has the ability to intercept and release metal ions such as lithium ions. Examples of negative electrode active materials include carbon materials, materials capable of forming alloys with metal ions, and oxide-based materials. An example of a carbon material is graphite. Examples of materials capable of forming alloys with lithium include silicon, silicon-containing oxides, tin, zinc alloys, bismuth, germanium, aluminum, and alloys mainly composed of materials capable of forming alloys with lithium. Examples of oxide-based materials include titanium oxide, lithium titanium oxide, niobium oxide, titanium niobium oxide, silicon-containing oxides, tin-containing oxides, iron oxides, zinc oxides, molybdenum oxide, vanadium oxide, and lithium-containing vanadium oxide. One of these negative electrode active materials may be used, or two or more may be used in combination. "Main component" means the component that is present in the largest amount by mass ratio.

[0038] Examples of conductive materials include carbon materials, conductive polymer compounds, and metals. Examples of carbon materials include carbon black, graphite, acetylene black, carbon nanotubes, carbon nanofibers, graphene, fullerenes, and graphite oxide. Examples of conductive polymer compounds include polyaniline, polypyrrole, and polythiophene. Examples of metals include aluminum and nickel.

[0039] Examples of binders include polymer materials such as polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-tetrafluoroethylene copolymer, polytetrafluoroethylene, carboxymethylcellulose, polyacrylic acid, styrene-butadiene copolymer rubber, polypropylene, polyethylene, and polyimide. Inorganic materials such as silicate-based, phosphate-based, and cement-based materials can also be used as binders.

[0040] Examples of solid electrolytes include halogenated solid electrolytes, sulfide solid electrolytes, oxide solid electrolytes, polymer solid electrolytes, and complex hydride solid electrolytes.

[0041] The solid electrolyte layer 43 is positioned between the first electrode layer 41 and the second electrode layer 42. Examples of solid electrolytes included in the solid electrolyte layer 43 include halide solid electrolytes, sulfide solid electrolytes, oxide solid electrolytes, polymer solid electrolytes, and complex hydride solid electrolytes. One of these solid electrolytes may be used, or two or more may be used in combination. The solid electrolyte included in the first electrode layer 41 may have the same composition as the solid electrolyte included in the solid electrolyte layer 43, or it may have a different composition. The solid electrolyte included in the second electrode layer 42 may have the same composition as the solid electrolyte included in the solid electrolyte layer 43, or it may have a different composition. The solid electrolyte included in the first electrode layer 41 may have the same composition as the solid electrolyte included in the second electrode layer 42, or it may have a different composition. The first electrode layer 41 may contain two or more types of solid electrolytes. The second electrode layer 42 may contain two or more types of solid electrolytes. In addition, the solid electrolyte layer 43 may contain not only a solid electrolyte, but also an electrolyte mixture containing a solid electrolyte and a binder used in the electrode layer.

[0042] In this embodiment, the battery element 40 does not have a metal current collector. The first electrode layer 41 may be the molded body of the positive electrode mixture itself. The second electrode layer 42 may be the molded body of the negative electrode mixture itself. The solid electrolyte layer 43 may be the molded body of the solid electrolyte or electrolyte mixture itself. If the solid electrolyte layer 43 has the shape of a thin film, the solid electrolyte layer 43 may be formed by a coating process. In the solid battery 100, the first electrode layer 41 is in direct contact with the first bottom terminal 22. The second electrode layer 42 is in direct contact with the second bottom terminal 23. With this configuration, when the battery element 40 is placed in the cavity CA and expanded, the reliability of the electrical connection between the battery element 40 and the ceramic package 10 can be increased. However, the first electrode layer 41 may have a metal current collector, and the second electrode layer 42 may have a metal current collector.

[0043] As shown in FIG. 1, only the space 32 exists between the battery element 40 and the lid body 30. That is, no pressing member is provided that exerts a force to press the battery element 40 toward the inner bottom surface 20b. No load is applied to the battery element 40 in the depth direction of the cavity CA. According to such a configuration, neither a pressing elastic conductive material member nor a special structure for fixing the member is required for the ceramic package 10. This advantageously contributes to the miniaturization, cost reduction, and improvement of the volume energy density of the solid-state battery 100. Further, not only the clearance 34 but also the space 32 can absorb the volume expansion accompanying the charge and discharge of the battery element 40. Also, an insulating sheet may be provided on the surface of the battery element 40 between the lid body 30 and the battery element 40 while maintaining the space 32. According to such a configuration, the occurrence of an internal short circuit due to foreign matter such as fine powder and metal powder moving in the space 32 can be prevented.

[0044] Note that the solid-state battery of the present disclosure may further include a pressing elastic conductive member or a pressing elastic conductive member and the above-described special structure for fixing the pressing member to the ceramic package. By providing the pressing member, vertical pressing in the depth direction of the cavity CA is also applied to the battery element 40, and the electrical characteristics of the solid-state battery become more stable.

[0045] Next, a method for manufacturing the solid-state battery 100 will be described.

[0046] FIG. 5 is a manufacturing process diagram of the solid-state battery 100. In step S1, the battery element 40 is manufactured. In step S2, the ceramic package 10 is manufactured. Specifically, the package body 20 and the lid body 30 are manufactured. The order of step S1 and step S2 is not limited.

[0047] The battery element 40 is manufactured such that the dimension in the width direction FD is shorter than the distance between the first inner side surfaces 20p and the first inner side surfaces 20p. According to such a configuration, the battery element 40 can be smoothly inserted into the cavity CA. The dimension of the battery element 40 in the stacking direction SD is shorter than the distance between the second inner side surfaces 20q and the second inner side surfaces 20q so that the clearance 34 is ensured.

[0048] The package body 20 can be manufactured by a known method. That is, a plurality of ceramic green sheets are laminated to form a laminate, and internal via wirings are produced. After firing the laminate, nickel plating is applied to the terminal portions of the fired product. A brazing material for joining the lid body 30 to the package body 20 is disposed on the open end face of the fired product. Thereafter, Au plating is applied on the nickel plating. Also, other conventional manufacturing methods of ceramic packages may be used.

[0049] After manufacturing the battery element 40 and the ceramic package 10, as shown in step S3 in FIG. 5, the battery element 40 is disposed in the cavity CA such that the first electrode layer 41 contacts the first bottom terminal 22 and the second electrode layer 42 contacts the second bottom terminal 23.

[0050] As shown in step S4, the battery element 40 is expanded in the width direction FD such that the first electrode layer 41 and the second electrode layer 42 respectively contact the first inner side surface 20p in the width direction FD and the restraining force from the ceramic package 10 (specifically, the package body 20) acts on the battery element 40. Thereby, the battery element 40 is fixed to the package body 20. According to the method of the present embodiment, the battery element 40 can be fixed to the ceramic package 10 without using means such as an elastic conductive member for pressing and soldering, and the reliability of the electrical connection between the ceramic package 10 and the battery element 40 can be improved.

[0051] In the present embodiment, in order to improve the adhesion between the battery element 40 and the first inner side surface 20p, it is desirable that the initial gap between the battery element 40 and the first inner side surface 20p is smaller than the expansion amount of the first electrode layer 41. According to such a configuration, the resistance of the solid-state battery 100 can be stabilized. For the same reason, it is desirable that the initial gap between the battery element 40 and the first inner side surface 20p is smaller than the expansion amount of the second electrode layer 42. It is desirable that the initial gap between the battery element 40 and the first inner side surface 20p is smaller than the expansion amount of the solid electrolyte layer 43.

[0052] Step S4 specifically includes charging the battery element 40. For example, in a solid-state battery, the positive and negative electrodes each expand by a few percent in volume during charging and discharging. Once a solid-state battery expands, it tends not to contract back to its original dimensions and maintains its expanded dimensions. Therefore, after placing the battery element 40 in the cavity CA, charging the battery element 40 causes it to expand and come into close contact with the first internal side surface 20p of the package body 20. As a result, the battery element 40 makes electrical contact with the first bottom terminal 22 and the second bottom terminal 23, respectively, making it possible to realize a low-resistance solid-state battery 100. Furthermore, this method does not require any special steps to fix the battery element 40 to the ceramic package 10.

[0053] Alternatively, the battery element 40 may be expanded by heating. In other words, the thermal expansion properties of the electrode material and solid electrolyte constituting the battery element 40 can be applied. A common indicator is the coefficient of linear expansion. In particular, the expansion amount of the electrode layer, which includes conductive materials with a large coefficient of linear expansion and binders with a large coefficient of linear expansion, tends to be large. The battery element 40 is manufactured by tablet molding a molded body including the electrode layer and the solid electrolyte layer. When the heating of the battery element 40 is finished and the temperature drops, the gaps between particles are difficult to fill. Therefore, once the battery element 40 expands, it is difficult to contract. Since the solid electrolyte also expands in volume, heating is more desirable from the viewpoint of constraining the battery element 40 and the ceramic package. For heating the battery element 40, a batch furnace, tunnel furnace, etc., can be used. Alternatively, the solder reflow process for mounting the solid battery 100 on a circuit board may be combined with heating. With this method, no special process is required to fix the battery element 40 to the ceramic package 10. If the heating temperature of the battery element 40 is lower than the reflow temperature in the solder reflow process, the restraining force will increase further after the solder reflow process for mounting the solid battery 100 onto the circuit board.

[0054] To expand the battery element 40, it is more effective to charge the battery element 40 while heating it. For example, the battery element 40 may be charged in a temperature environment of 85°C, 100°C, 125°C, or 150°C. Heating also reduces the resistance of the battery element 40, and the charging time can be significantly shortened compared to room temperature, thus greatly improving work efficiency. In addition, the battery element 40 may be heated after charging, or heated before charging. Furthermore, heating and charging of the battery element 40 may be performed simultaneously. Note that "heating and charging simultaneously" does not necessarily mean that the start and end times of heating coincide with the start and end times of charging, but rather that at least a portion of the heating process overlaps with the charging process.

[0055] Step S4 may be performed before joining the lid 30 to the package body 20, or after joining the lid 30 to the package body 20.

[0056] (Embodiment 2) Figure 6 is a cross-sectional view of the solid battery according to Embodiment 2 along the line VI-VI. Figure 7 is a plan view of the solid battery with the cover removed. Figure 8 is a perspective view of the package body 20S. The solid battery 200 includes a ceramic package 10S.

[0057] The ceramic package 10S further comprises electrically insulating protrusions 27 provided on each of a pair of first internal sides 20p. The protrusions 27 are located facing the solid electrolyte layer 43. The solid electrolyte layer 43 is in contact with one or both of the pair of protrusions 27.

[0058] As explained earlier, the battery element 40 expands due to charging or heating. However, the solid electrolyte layer 43 hardly expands with charging. Therefore, with the ceramic package 10 of Embodiment 1, a small gap may occur between the solid electrolyte layer 43 and the first internal side surface 20p of the ceramic package 10. In contrast, with the ceramic package 10S, the solid electrolyte layer 43 can be supported by the protrusions 27. Combined with the restraining force acting from the ceramic package 10S on the first electrode layer 41 and the second electrode layer 42, the battery element 40 can be fixed inside the ceramic package 10S by the protrusions 27. The protrusions 27 are provided at a position facing the solid electrolyte layer 43. Since the solid electrolyte layer 43 also expands when heating or charging while heating is performed, the effect of fixing the battery element 40 inside the ceramic package 20S by the protrusions 27 is further enhanced. In addition, the protrusions 27 prevent the first electrode layer 41 and the second electrode layer 42 from wrapping around the side surface of the solid electrolyte layer 43 when the battery element 40 expands. Therefore, the projection 27 can prevent internal short circuits between the first electrode layer 41 and the second electrode layer 42 that occur when the battery element 40 expands during charging and discharging.

[0059] One of the challenges associated with charging and discharging solid-state batteries is internal short circuits caused by cracks occurring in the electrode layer or at the interface between the electrode layer and the solid electrolyte layer at the ends of the battery element in the width direction FD. According to this embodiment, by providing the protrusion 27, internal short circuits between the first electrode layer 41 and the second electrode layer 42 can be prevented.

[0060] The ceramic package 10S includes a package body 20S. Except for the protrusions 27, the structure of the package body 20S is the same as that of the package body 20 described in Embodiment 1.

[0061] In this embodiment, the projection 27 is a ceramic portion integrally formed on the package body 20S. With this configuration, no additional steps or additional parts are required to form the projection 27.

[0062] The projection 27 is located within the range where the solid electrolyte layer 43 exists in the stacking direction SD of the battery element 40. The dimensions (width) of the projection 27 in the stacking direction SD may be equal to, smaller than, or larger than the dimensions (thickness) of the solid electrolyte layer 43 in the stacking direction SD. Preferably, the dimensions (width) of the projection 27 in the stacking direction SD are equal to or smaller than the dimensions (thickness) of the solid electrolyte layer 43 in the stacking direction SD. The "projection height" of the projection 27 refers to the projection height from the first internal side surface 20p, and the projection height is at least greater than zero.

[0063] In this embodiment, the projections 27 are provided on each of the pair of first internal surfaces 20p. With this configuration, both end faces of the solid electrolyte layer 43 can be supported by the projections 27. However, the projections 27 may be in contact with only one of the two end faces of the solid electrolyte layer 43. Also, the projections 27 may be provided on only one of the pair of first internal surfaces 20p.

[0064] As shown in Figure 7, after expansion in step S4 of the manufacturing process, the first electrode layer 41 and the second electrode layer 42 are in contact with the first internal surface 20p, and the solid electrolyte layer 43 is in contact with the projection 27. The dimensions of the width direction FD in Figure 4 may be determined in advance, taking into account the amount of expansion of the electrode layers and solid electrolyte of the battery element 40, or at least one selected from the first electrode layer 41 and the second electrode layer 42 may be larger than the solid electrolyte layer 43 in the width direction FD. If the electrode layer is larger than the solid electrolyte layer 43, an effect such as preventing misalignment of the stacking direction SD of the cavity CA of the ceramic package 10S during insertion can be expected. In addition, it is easier to apply a restraining force from the ceramic package 10S by at least one selected from the first electrode layer 41 and the second electrode layer 42.

[0065] The projection 27 preferably extends from the inner bottom surface 20b to the upper end surface of the package body 20S, but it does not have to extend to the upper end surface. If it does not extend to the upper end surface, it is preferable that the dimension (height) of the projection 27 in the depth direction of the cavity CA is greater than the dimension (height) of the battery element 40. With this configuration, the projection 27 can support the solid electrolyte layer 43, and the effect of preventing internal short circuits between the first electrode layer 41 and the second electrode layer 42 is also enhanced.

[0066] In the examples shown in Figures 7 and 8, the projection 27 has the shape of a rectangular prism. However, the shape of the projection 27 is not particularly limited. Figure 9 shows other shapes of the projection 27.

[0067] As shown in Figure 9(a), the projection 27 may have a triangular prism shape. With the projection 27 shown in Figure 9(a), the tip of the projection 27 is a point. Therefore, compared to a projection 27 with a rectangular prism shape, it becomes easier to insert the battery element 40 into the package body 20S, and the gap between the solid electrolyte layer 43 and the projection 27 can be made smaller. Furthermore, the projection 27 shown in Figure 9(a) is desirable because it can secure space that can accommodate irregular volume changes between the end of the solid electrolyte layer 43 and the end of the first electrode layer 41 or the second electrode layer 42 in the width direction FD.

[0068] As shown in Figure 9(b), the projection 27 may have a semi-cylindrical shape. With the projection 27 shown in Figure 9(b), the tip of the projection 27 becomes a point. Therefore, compared to a projection 27 with a rectangular prism shape, it becomes easier to insert the battery element 40 into the package body 20S, and the gap between the battery element 40 and the projection 27 can be made smaller. Furthermore, the projection 27 shown in Figure 9(b) is desirable because it can accommodate irregular volume changes between the end of the solid electrolyte layer 43 and the end of the first electrode layer 41 or the second electrode layer 42 in the width direction FD with a curved surface.

[0069] As shown in Figure 9(c), the projection 27 may have the shape of a trapezoidal column.

[0070] As shown in Figures 9(d), (e), and (f), the projection 27 may be composed of a plurality of parts 27a aligned in the stacking direction SD. When the projection 27 is composed of a plurality of parts 27a, the projection 27 is provided such that the solid electrolyte layer 43 is in contact with at least one of the parts 27a. When the projection 27 is provided such that some or all of the plurality of parts 27a are in contact with the solid electrolyte layer 43, in addition to fixing the solid electrolyte layer 43, the effect of preventing internal short circuits is further enhanced. When the projection 27 is composed of a plurality of parts 27a, it is not necessary for all of the plurality of parts 27a to have the same dimensions. For example, the projection 27 may be designed such that the central part 27a has the largest projection height. By arranging the part 27a with the largest projection height to be in contact with the solid electrolyte layer 43, the solid electrolyte layer 43 can be fixed more securely, and the effect of preventing internal short circuits is further enhanced. Furthermore, although not shown in the figures, if the projection 27 is composed of multiple parts 27a, the projection 27 may be made up of two or more parts selected from a triangular prism, a semi-cylinder, and a trapezoidal prism.

[0071] (Embodiment 3) Figure 10 is a cross-sectional view of the solid battery 300 according to Embodiment 3 along line XX. Figure 11 is a plan view of the solid battery 300 with the cover 30 removed. Figure 12 is a perspective view of the package body 20T.

[0072] The solid-state battery 300 comprises a ceramic package 10T and a battery element 40. The ceramic package 10T further comprises a pair of first side terminals 24 and a pair of second side terminals 25. The pair of first side terminals 24 are provided on each of a pair of first internal side surfaces 20p and are electrically connected to a first bottom terminal 22. The pair of second side terminals 25 are provided on each of a pair of first internal side surfaces 20p and are electrically connected to a second bottom terminal 23. Each of the first side terminals 24 and the second side terminals 25 constitutes a part of the first internal side surface 20p. A projection 27 is located between the first side terminals 24 and the second side terminals 25. The first electrode layer 41 of the battery element 40 is in contact with the first bottom terminal 22 and the first side terminals 24. The second electrode layer 42 of the battery element 40 is in contact with the second bottom terminal 23 and the second side terminals 25.

[0073] The ceramic package 10T includes a package body 20T. Except for the first side terminals 24 and the second side terminals 25, the structure of the package body 20T is the same as that of the package body 20S described in Embodiment 2.

[0074] In this embodiment as well, the battery element 40 is constrained by the ceramic package 10T in the width direction FD. That is, the first electrode layer 41 of the battery element 40 is pressed against the first side terminal 24, and the second electrode layer 42 of the battery element 40 is pressed against the second side terminal 25. As a result, the battery element 40 is fixed to the ceramic package 10T.

[0075] According to this embodiment, not only the first bottom terminal 22 and the second bottom terminal 23, but also the first side terminal 24 and the second side terminal 25 are in contact with the battery element 40. This improves the reliability of the electrical connection between the ceramic package 10T and the battery element 40. As a result, the electrical characteristics of the solid battery 300, such as rate characteristics, are improved or stabilized.

[0076] As shown in Figure 12, the first side terminal 24 is in contact with the short side of the first bottom terminal 22 in the stacking direction SD and extends in the depth direction of the cavity CA. The second side terminal 25 is in contact with the short side of the second bottom terminal 23 in the stacking direction SD and extends in the depth direction of the cavity CA. The shape of the first side terminal 24 may be the same as or different from the shape of the second side terminal 25. The dimensions of the first side terminal 24 may be equal to or different from the dimensions of the second side terminal 25. The depth dimensions of the first side terminal 24 and the second side terminal may be equal to, lower than, or higher than the dimensions (height) of the paired first electrode layer 41 and second electrode layer 42, respectively. The depth dimensions of the first side terminal 24 and the second side terminal may be equal to, or preferably higher than, the dimensions (height) of the paired first electrode layer 41 and second electrode layer 42, respectively.

[0077] In this embodiment, the first side terminal 24 is provided on each of the pair of first internal side surfaces 20p. The second side terminal 25 is provided on each of the pair of first internal side surfaces 20p. With this configuration, the reliability of the electrical connection between the ceramic package 10T and the battery element 40 can be further improved. However, the first side terminal 24 may be provided on only one of the pair of first internal side surfaces 20p. The second side terminal 25 may be provided on only one of the pair of first internal side surfaces 20p.

[0078] Similar to the first bottom terminal 22, the second bottom terminal 23, the via conductor 28, and the external terminals (first external terminal and second external terminal), the pair of first side terminals 24 and the pair of second side terminals 25 are made of metallic materials such as W, Mo, Cu, Ag, Cu alloy, and Ag alloy. The surfaces of the pair of first side terminals 24 and the pair of second side terminals 25 are plated with Ni and Au.

[0079] In this embodiment as well, the battery element 40 does not have a metal current collector. In the solid battery 300, the first electrode layer 41 is in direct contact with the first bottom terminal 22 and the first side terminal 24. The second electrode layer 42 is in direct contact with the second bottom terminal 23 and the second side terminal 25. With this configuration, when the battery element 40 is placed in the cavity CA and expanded, the reliability of the electrical connection between the battery element 40 and the ceramic package 10T can be improved. However, the first electrode layer 41 may have a metal current collector, and the second electrode layer 42 may have a metal current collector.

[0080] The protruding height of the projection 27 is the same as or greater than that of the first side terminal 24 and the second side terminal 25.

[0081] The solid-state battery 300 can be manufactured by the method described with reference to Figure 5.

[0082] In step S1, the battery element 40 is manufactured such that its dimensions in the width direction FD are shorter than the distance between the first side terminals 24 and the first side terminals 24, the distance between the second side terminals 25 and the second side terminals 25, and the distance between the protrusions 27 and the protrusions 27.

[0083] In this embodiment, in order to improve the adhesion between the battery element 40 and the first side terminal 24, it is desirable that the initial gap between the battery element 40 and the first side terminal 24 before the battery element 40 expands is smaller than the amount of expansion of the first electrode layer 41. Similarly, in order to improve the adhesion between the battery element 40 and the second side terminal 25, it is desirable that the initial gap between the battery element 40 and the second side terminal 25 before the battery element 40 expands is smaller than the amount of expansion of the second electrode layer 42. With such a configuration, the resistance of the solid battery 300 can be stabilized.

[0084] According to the method of this disclosure, the battery element 40 can be fixed to the ceramic package 10, 10S, or 10T, and the reliability of the electrical connection between the ceramic package 10, 10S, or 10T and the battery element 40 can be improved.

[0085] (Other Embodiments) (Note) The above description of embodiments discloses the following technologies.

[0086] (Technology 1) A ceramic package having a cavity formed therein having two pairs of sides parallel to each other when viewed from a first surface in plan view, and a battery element disposed within the cavity and having two pairs of sides parallel to each other when viewed from a plan view, wherein the battery element includes a first electrode layer, a solid electrolyte layer, and a second electrode layer, and when the direction perpendicular to the stacking direction of the first electrode layer, the solid electrolyte layer, and the second electrode layer and the depth direction of the cavity is defined as the width direction, the stacking direction and the depth direction are perpendicular, the cavity includes an opening formed on the first surface, an internal bottom surface located opposite to the opening in the depth direction, a pair of first internal sides facing each other in the width direction, and a pair of second internal sides facing each other in the stacking direction, the ceramic package includes a first bottom terminal provided on the internal bottom surface and a second bottom terminal provided on the internal bottom surface so as to be insulated from the first bottom terminal, A solid-state battery in which the first electrode layer is in contact with the first bottom terminal and the pair of first internal surfaces, and the second electrode layer is in contact with the second bottom terminal and the pair of first internal surfaces, and the battery element is constrained in the width direction by the ceramic package.

[0087] The technology described herein can improve the reliability of electrical connections in solid-state batteries using ceramic packages.

[0088] (Technical 2) The solid battery according to Technical 1, wherein at least one of the pair of first internal sides is provided with an electrically insulating projection at a position facing the solid electrolyte layer. With such a configuration, internal short circuits can be prevented.

[0089] (Technology 3) The solid battery according to Technology 2, wherein the solid electrolyte layer is in contact with the protrusions. With this configuration, the solid electrolyte layer can be supported by the protrusions.

[0090] (Technical 4) The solid battery according to any one of Technical 1 to 3, wherein the ceramic package further comprises a first side terminal constituting the first internal side surface and a second side terminal constituting the first internal side surface, the first side terminal being electrically connected to the first bottom terminal, the second side terminal being electrically connected to the second bottom terminal, the first electrode layer being in contact with the first side terminal, and the second electrode layer being in contact with the second side terminal. With such a configuration, the reliability of the electrical connection between the ceramic package and the battery element can be improved.

[0091] (Technical 5) A solid battery according to any one of Technical 1 to 4, wherein a gap exists between at least one of the pair of second internal surfaces and the battery element in a direction parallel to the stacking direction. Such a gap can absorb dimensional variations of the battery element in the stacking direction.

[0092] (Technical 6) A solid-state battery according to any one of Technical 1 to 5, wherein each of the first electrode layer and the second electrode layer has a pair of short sides and a pair of long sides that are parallel to each other when viewed from above, the stacking direction is parallel to the short sides, and the battery element is constrained by the ceramic package in the direction parallel to the long sides. With such a configuration, it is easy to apply a constraining force by the ceramic package to the battery element.

[0093] (Technical 7) A method for manufacturing a solid-state battery, wherein the solid-state battery comprises a ceramic package having a cavity formed thereon having two pairs of sides parallel to each other when viewed from a first surface in plan view, and a battery element disposed within the cavity and having two pairs of sides parallel to each other when viewed from a plan view, the battery element includes a first electrode layer, a solid electrolyte layer, and a second electrode layer, and when the direction perpendicular to the stacking direction of the first electrode layer, the solid electrolyte layer, and the second electrode layer and the depth direction of the cavity are defined as the width direction, the stacking direction and the depth direction are perpendicular, the cavity includes an opening formed on the first surface, an internal bottom surface located opposite to the opening in the depth direction, a pair of first internal sides facing each other in the width direction, and a pair of second internal sides facing each other in the stacking direction, the ceramic package comprises a first bottom terminal provided on the internal bottom surface and a second bottom terminal provided on the internal bottom surface so as to be insulated from the first bottom terminal, and the manufacturing method is A method for manufacturing a solid battery, comprising: manufacturing the battery element such that the dimensions of the first electrode layer, the solid electrolyte layer, and the second electrode layer are shorter than the distance between the pair of first internal sides in the stacking direction and the width direction; arranging the battery element in the cavity such that the first electrode layer is in contact with the first bottom terminal and the second electrode layer is in contact with the second bottom terminal; and expanding the battery element in the width direction.

[0094] According to this disclosure, a battery element can be fixed to a ceramic package, and the reliability of the electrical connection between the ceramic package and the battery element can be improved.

[0095] (Technical 8) A method for manufacturing a solid battery according to Technical 7, wherein expanding the battery element includes at least one selected from charging the battery element and heating the battery element. With such a method, no special steps are required to fix the battery element in the ceramic package.

[0096] (Technical 9) A method for manufacturing a solid battery according to Technical 7 or 8, wherein expanding the battery element includes heating the battery element after charging, charging the battery element after heating, or heating and charging the battery element simultaneously. Performing the two processes of charging and heating simultaneously is more effective from the viewpoint of expanding the battery element. Furthermore, when charging while heating the battery element, the resistance of the battery element decreases due to heating, and the charging time can be significantly shortened compared to room temperature, which is desirable from the viewpoint of productivity of solid batteries.

[0097] The technology disclosed herein is useful for solid-state batteries equipped with ceramic packages.

[0098] 10, 10S, 10T Ceramic package 20, 20S, 20T Package body 20b Internal bottom surface 20p First internal side surface 20q Second internal side surface 22 First bottom terminal 23 Second bottom terminal 24 First side terminal 25 Second side terminal 27 Protrusion 28 Via conductor 29 First external terminal 30 Cover 32 Space 34 Gap 40 Battery element 41 First electrode layer 42 Second electrode layer 43 Solid electrolyte layer 100, 200, 300 Solid battery CA Cavity SD Stacking direction FD Width direction

Claims

1. A ceramic package having a cavity formed therein, having two pairs of sides parallel to each other when viewed from a first surface in plan view; a battery element disposed within the cavity and having two pairs of sides parallel to each other when viewed from a plan view; wherein the battery element includes a first electrode layer, a solid electrolyte layer, and a second electrode layer; the width direction is defined as the direction perpendicular to the stacking direction of the first electrode layer, the solid electrolyte layer, and the second electrode layer and the depth direction of the cavity, the stacking direction and the depth direction are perpendicular; the cavity includes an opening formed on the first surface, an internal bottom surface located opposite to the opening in the depth direction, a pair of first internal sides facing each other in the width direction, and a pair of second internal sides facing each other in the stacking direction; the ceramic package includes a first bottom terminal provided on the internal bottom surface and a second bottom terminal provided on the internal bottom surface so as to be insulated from the first bottom terminal. A solid-state battery in which the first electrode layer is in contact with the first bottom terminal and the pair of first internal surfaces, and the second electrode layer is in contact with the second bottom terminal and the pair of first internal surfaces, and the battery element is constrained in the width direction by the ceramic package.

2. The solid battery according to claim 1, wherein at least one of the pair of first internal surfaces is provided with an electrically insulating projection at a position facing the solid electrolyte layer.

3. The solid battery according to claim 2, wherein the solid electrolyte layer is in contact with the protrusion.

4. The solid battery according to claim 1, wherein the ceramic package further comprises a first side terminal constituting the first internal side surface and a second side terminal constituting the first internal side surface, the first side terminal being electrically connected to the first bottom terminal, the second side terminal being electrically connected to the second bottom terminal, the first electrode layer being in contact with the first side terminal, and the second electrode layer being in contact with the second side terminal.

5. The solid battery according to claim 1, wherein a gap exists between at least one of the pair of second internal surfaces and the battery element in a direction parallel to the stacking direction.

6. The solid-state battery according to claim 1, wherein each of the first electrode layer and the second electrode layer has a pair of short sides and a pair of long sides that are parallel to each other when viewed from above, the stacking direction is parallel to the short sides, and the battery element is constrained by the ceramic package in the direction parallel to the long sides.

7. A method for manufacturing a solid-state battery, wherein the solid-state battery comprises a ceramic package having a cavity formed thereon having two pairs of sides parallel to each other when viewed from a first surface in plan view, and a battery element disposed within the cavity and having two pairs of sides parallel to each other when viewed from a plan view, the battery element comprising a first electrode layer, a solid electrolyte layer, and a second electrode layer, and the width direction defined as the direction perpendicular to the stacking direction of the first electrode layer, the solid electrolyte layer, and the second electrode layer and the depth direction of the cavity, the stacking direction and the depth direction are perpendicular to each other, the cavity comprising an opening formed on the first surface, an internal bottom surface located opposite to the opening in the depth direction, a pair of first internal sides facing each other in the width direction, and a pair of second internal sides facing each other in the stacking direction, the ceramic package comprising a first bottom terminal provided on the internal bottom surface and a second bottom terminal provided on the internal bottom surface so as to be insulated from the first bottom terminal, and the manufacturing method is A method for manufacturing a solid battery, comprising: manufacturing the battery element such that the dimensions of the first electrode layer, the solid electrolyte layer, and the second electrode layer are shorter than the distance between the pair of first internal sides in the stacking direction and the width direction; arranging the battery element in the cavity such that the first electrode layer is in contact with the first bottom terminal and the second electrode layer is in contact with the second bottom terminal; and expanding the battery element in the width direction.

8. The method for manufacturing a solid battery according to claim 7, wherein expanding the battery element includes at least one selected from charging the battery element and heating the battery element.

9. The method for manufacturing a solid battery according to claim 7, wherein expanding the battery element includes heating the battery element after charging it, charging the battery element after heating it, or heating and charging the battery element simultaneously.

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