Solid-state battery and method for manufacturing solid-state battery

Abstract

To provide a solid-state battery capable of suppressing migration of a component contained in an inner layer of an external connection terminal.SOLUTION: The solid-state battery 1 includes, for example, a battery main body 10 having a laminate 14 including a first electrode layer 11 and an electrolytic layer 13 laminated on a first direction D1, and an insulating layer 15 covering the laminate 14, and having an end surface D1 facing a second direction D2 orthogonal to the first direction 10a and in which a part of the first electrode layer 11 is exposed from the insulating layer 15, and an outer surface 10c continuous therefrom. The solid-state battery 1 further includes a conductive layer 41 and metal films 22 and 23 as the external connection terminal 20. The conductive layer 41 covers the end surface 10a portion, is connected to a portion of the first electrode layer 11, and extends from the end surface 10a portion to the outer surface 10c portion. The conductive layer 41 includes a conductive material containing carbon and an insulating material containing glass, and exhibits conductivity by the conductive material. The metal films 22 and 23 are provided to cover the conductive layer 41.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a solid-state battery and a method for manufacturing a solid-state battery. [Background technology]

[0002] Regarding solid-state batteries, when terminals contain metal components such as Ag (silver) particles contained in conductive resin, a technique is known in which the movement of metal components that tend to migrate is suppressed by a solder plating film (Patent Document 1).

[0003] Also known is a technology in which a conductive layer having water vapor barrier properties is provided in the gap between an end surface electrode provided on the base body of an electronic component such as a solid-state battery or a multilayer ceramic capacitor and a metal cap attached thereto, and the surface of the base body is covered with a non-conductive film having water vapor barrier properties while leaving part of the end surface electrode exposed (Patent Document 2).

[0004] In addition, a technology is known in which external electrodes each having a base electrode layer and a plating layer covering the base electrode layer are provided on the end faces and main surfaces of the laminate of a multilayer ceramic electronic component, and a semiconductor layer, which is a porous layer of a ceramic sintered body having many oxygen defects, is provided at the interface between the laminate and the external electrode (Patent Document 3). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2022 / 153642 Brochure [Patent Document 2] Japanese Patent Publication No. 2020-87588 [Patent Document 3] Japanese Patent Publication No. 2020-202220 Summary of the Invention [Problem to be solved by the invention]

[0006] In some solid-state batteries, an external connection terminal is employed in which an external electrode layer containing a component such as Ag is provided to cover the end face of a battery body including an electrode layer and an electrolyte layer, and a metal film such as a plated film is provided on the surface of the external electrode layer. However, in such external connection terminals of solid-state batteries, even if a migration-resistant material is used for the outer metal film, if a part of the inner external electrode layer, such as the edge, is exposed from the outer metal film, the component such as Ag contained in the external electrode layer may react with external moisture, causing migration of the component. If migration occurring in an external connection terminal on one electrode side of a solid-state battery extends to the external connection terminal on the other electrode side, it may cause a short circuit of the solid-state battery.

[0007] An object of the present invention is to realize a solid-state battery in which migration of components contained in the inner layer of an external connection terminal is suppressed. [Means for solving the problem]

[0008] In one aspect, there is provided a solid-state battery including: a battery body having a laminate including an electrode layer and an electrolyte layer stacked in a first direction; and an insulating layer covering the laminate, the battery body having an end face facing a second direction perpendicular to the first direction, where a portion of the electrode layer is exposed from the insulating layer, and an outer surface continuous with the end face; a conductive layer covering the end face, connected to the portion of the electrode layer, and extending from the end face to the outer surface, the conductive layer including a conductive material containing carbon and an insulating material containing glass, and exhibiting conductivity due to the conductive material; and a metal film covering the conductive layer.

[0009] In another aspect, a method for manufacturing such a solid-state battery is provided. [Effects of the Invention]

[0010] This makes it possible to realize a solid-state battery in which migration of components contained in the inner layer of the external connection terminal is suppressed. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is an external view of an example of a solid-state battery. [Figure 2] FIG. 1 is a cross-sectional view of an example of a solid-state battery. [Figure 3] FIG. 1 is a diagram (part 1) illustrating a configuration example of a solid-state battery according to a first embodiment. [Figure 4] FIG. 2 is a diagram (part 2) illustrating a configuration example of the solid-state battery according to the first embodiment. [Figure 5] FIG. 3 is a diagram (part 3) illustrating a configuration example of the solid-state battery according to the first embodiment. [Figure 6] 3A to 3C are diagrams illustrating an example of a method for manufacturing the solid-state battery according to the first embodiment. [Figure 7] FIG. 1 is a diagram (part 1) illustrating a configuration example of a solid-state battery according to a second embodiment. [Figure 8] FIG. 10 is a diagram (part 2) illustrating a configuration example of a solid-state battery according to a second embodiment. [Figure 9] 10A to 10C are diagrams illustrating an example of a method for manufacturing a solid state battery according to a second embodiment. [Figure 10] 10A and 10B are diagrams illustrating an example of the configuration of a battery body according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] Fig. 1 is an external view of an example of a solid-state battery, which is a schematic perspective view of the external appearance of a main part of the example of the solid-state battery. The solid-state battery 1 shown in FIG. 1 is an example of a lithium-ion battery. The solid-state battery 1 includes a battery body 10, an external connection terminal 20, and an external connection terminal 30. The battery body 10 has therein a positive electrode layer and a negative electrode layer, which are electrode layers, and an electrolyte layer provided therebetween. The electrode layers and electrolyte layer inside the battery body 10 will be described later. The external connection terminal 20 and the external connection terminal 30 are provided on one end surface side and the other end surface side of the battery body 10, respectively. The external connection terminal 20 is connected to one of the positive electrode layer and the negative electrode layer provided inside the battery body 10, and the external connection terminal 30 is connected to the other of the positive electrode layer and the negative electrode layer provided inside the battery body 10. Of the external connection terminal 20 and the external connection terminal 30, the one connected to the positive electrode layer of the battery body 10 functions as the positive electrode terminal of the solid-state battery 1, and the one connected to the negative electrode layer of the battery body 10 functions as the negative electrode terminal of the solid-state battery 1.

[0013] Fig. 2 is a cross-sectional view of an example of a solid-state battery. Fig. 2 shows a schematic cross-sectional view of a main part of an example of a solid-state battery. Fig. 2 is a schematic cross-sectional view of an example of a solid-state battery taken along line L1 in Fig. 1.

[0014] The solid-state battery 1a shown in FIG. 2 is an example of a solid-state battery manufactured as having the external appearance shown in FIG. 1. As shown in FIG. 2, the battery body 10 of the solid-state battery 1a includes a stack 14 in which a first electrode layer 11 and a second electrode layer 12 are stacked in a first direction D1 with an electrolyte layer 13 interposed therebetween, and an insulating layer 15 covering the stack 14. One of the first electrode layer 11 and the second electrode layer 12 is a positive electrode layer, and the other is a negative electrode layer. An external connection terminal 20 and an external connection terminal 30 are provided on end faces 10a and 10b, respectively, of the battery body 10 facing a second direction D2 perpendicular to the first direction D1. A portion of the first electrode layer 11 exposed from the insulating layer 15 is provided on one end face 10a of the battery body 10. The first electrode layer 11 is connected to the external connection terminal 20 provided on the end face 10a. Further, a part of the second electrode layer 12 exposed from the insulating layer 15 is provided on the other end surface 10b of the battery body 10. The second electrode layer 12 is connected to an external connection terminal 30 provided on the end surface 10b.

[0015] The external connection terminal 20 includes, for example, an external electrode layer 21, a metal film 22, and a metal film 23. The external electrode layer 21 covers the end face 10a and extends from the end face 10a to a part of the outer face 10c that is continuous with the end face 10a. The metal film 22 is provided to cover the external electrode layer 21, and the metal film 23 is provided to cover the metal film 22. The external connection terminal 30 includes, for example, an external electrode layer 31, a metal film 32, and a metal film 33. The external electrode layer 31 covers the end face 10b and extends from the end face 10b to a part of the outer face 10c that is continuous with the end face 10b. The metal film 32 is provided to cover the external electrode layer 31, and the metal film 33 is provided to cover the metal film 32.

[0016] The external electrode layer 21 is formed by applying a paste containing a conductive component such as Ag to the end face 10a and a portion of the outer surface 10c, followed by heat treatment. Similarly, the external electrode layer 31 is formed by applying a paste containing a conductive component such as Ag to the end face 10b and a portion of the outer surface 10c, followed by heat treatment. The external electrode layer 21 and the external electrode layer 31 are connected to the first electrode layer 11 and the second electrode layer 12, respectively.

[0017] The metal films 22 and 32 are formed by depositing a metal material such as Ni (nickel) on the surfaces of the external electrode layers 21 and 31 using a plating method. The metal films 23 and 33 are formed by depositing a metal material such as Sn (tin) on the surfaces of the metal films 22 and 32 using a plating method. The metal films 22 and 23 that cover the external electrode layer 21 and the metal films 32 and 33 that cover the external electrode layer 31 have relatively high moisture barrier properties and can therefore function as protective films that protect the external electrode layers 21 and 31 from external moisture.

[0018] However, it may be difficult to form the metal films 22 and 23, and the metal films 32 and 33, on the insulating layer 15 that forms the outer surface 10c of the battery body 10. Therefore, for example, as shown in FIG. 2 , the external electrode layer 21, which is the inner layer of the external connection terminal 20, may not be sufficiently covered by the metal films 22 and 23, which are the outer layers, and a gap may be formed that leads to a part of the external electrode layer 21, such as the edge 21a, of the external electrode layer 21. In other words, a part of the internal external electrode layer 21 may be exposed from the metal films 22 and 23, which are the outer layers. Similarly, as shown in FIG. 2 , the external electrode layer 31, which is the inner layer of the external connection terminal 30, may not be sufficiently covered by the metal films 32 and 33, which are the outer layers, and a gap may be formed that leads to a part of the external electrode layer 31, such as the edge 31a, of the external electrode layer 31. In other words, a part of the internal external electrode layer 31 may be exposed from the metal films 32 and 33, which are the outer layers.

[0019] When gaps are formed in the external electrode layer 21 or the external electrode layer 31, components such as Ag contained in the external electrode layer 21 or the external electrode layer 31 may react with external moisture, resulting in migration of the components. Such migration may lead to performance degradation of the solid-state battery 1a. For example, as shown in FIG. 2, components such as Ag contained in the external electrode layer 21 may react with external moisture 101 that penetrates through gaps between the metal film 22 and the metal film 23, resulting in migration 100. If this migration 100 extends to the external electrode layer 31, which is the counter electrode, as shown by the dotted line in FIG. 2, it may lead to a short circuit of the solid-state battery 1a.

[0020] In view of the above, the following configuration is adopted as an embodiment to realize a solid-state battery in which migration of components contained in the inner layer of the external connection terminal is suppressed. [First embodiment] 3 to 5 are diagrams illustrating an example of the configuration of the solid-state battery according to the first embodiment. Each of FIGS. 3 to 5 shows a cross-sectional view of a main part of the example of the configuration of the solid-state battery according to the first embodiment. Here, FIG. 3 is a cross-sectional view taken along line L1 in FIG. 1 when the example of the configuration of the solid-state battery according to the first embodiment is employed. FIG. 4 is a cross-sectional view taken along line L2 in FIG. 1 when the example of the configuration of the solid-state battery according to the first embodiment is employed. FIG. 5 is a cross-sectional view taken along line L3 in FIGS. 1 and 3 when the example of the configuration of the solid-state battery according to the first embodiment is employed.

[0021] 3 to 5 is an example of a lithium ion battery. The solid state battery 1 shown in FIGS. The battery body 10 includes a stack 14 in which first electrode layers 11 and second electrode layers 12 are stacked in a first direction D1 with electrolyte layers 13 interposed therebetween, and an insulating layer 15 covering the stack 14. For example, a plurality of first electrode layers 11 and a plurality of second electrode layers 12 are alternately stacked in the first direction D1 with electrolyte layers 13 interposed therebetween. The top and bottom layers of the stack 14 may be the first electrode layers 11 or the second electrode layers 12, or may be electrolyte layers 13 as shown in Figures 3 to 5. One of the first electrode layers 11 and the second electrode layers 12 is a positive electrode layer, and the other is a negative electrode layer. That is, the first electrode layer 11 is a positive electrode layer and the second electrode layer 12 is a negative electrode layer, or the first electrode layer 11 is a negative electrode layer and the second electrode layer 12 is a positive electrode layer. Note that one or both of the first electrode layer 11 and the second electrode layer 12 may also be simply referred to as "electrode layer."

[0022] As shown in FIG. 3, the battery body 10 has end faces 10a and 10b facing in a second direction D2 orthogonal to a first direction D1. For example, a part (side surface) of the first electrode layer 11 exposed from the insulating layer 15 is provided on one end face 10a of the battery body 10, and a part (side surface) of the second electrode layer 12 exposed from the insulating layer 15 is provided on the other end face 10b. The first electrode layer 11 and the second electrode layer 12 of the battery body 10 are sized such that, for example, as shown in FIG. 4, they have the same width in a third direction D3 orthogonal to the first direction D1 and the second direction D2. The insulating layer 15 of the battery body 10 as shown in FIGS. 3 and 4 is also referred to as a "cover layer". Among the insulating layer 15, the portion adjacent to the side (third direction D3) of the electrolyte layer 13, the portion adjacent to the side (second direction D2 and third direction D3) of the first electrode layer 11, and the portion adjacent to the side (second direction D2 and third direction D3) of the second electrode layer 12 are also referred to as "embedded layers".

[0023] <## Here, the electrolyte layer 13 of the laminate 14 of the battery body 10 contains a solid electrolyte. For example, an oxide solid electrolyte is used as the solid electrolyte of the electrolyte layer 13. As the oxide solid electrolyte of the electrolyte layer 13, for example, LAGP, which is one type of NASICON (Na super ionic conductor) type (also referred to as "NASICON type") oxide solid electrolyte, is used. LAGP is an oxide solid electrolyte represented by the general formula Li 1+x Al x Ge 2-x (PO4)3 (0 < x ≦ 1). In addition, a sulfide solid electrolyte such as Li2S (lithium sulfide)-P2S5 (diphosphorus pentasulfide) may be used as the solid electrolyte of the electrolyte layer 13.

[0024] The positive electrode layer (first electrode layer 11 or second electrode layer 12) of the laminate 14 of the battery body 10 includes a positive electrode active material, a conductive additive, and a solid electrolyte. The solid electrolyte of the positive electrode layer is an oxide solid electrolyte or a sulfide solid electrolyte, for example, the same type of material as the solid electrolyte used in the electrolyte layer 13. The positive electrode active material of the positive electrode layer is, for example, Li2CoP2O7 (lithium cobalt pyrophosphate, also referred to as "LCPO") or the like. The conductive additive of the positive electrode layer is, for example, a carbon material such as carbon fiber, carbon black, graphite, graphene, or carbon nanotubes, or a conductive material such as iron silicide. The positive electrode layer is connected to either the external connection terminal 20 or the external connection terminal 30 (the terminal different from the one to which the negative electrode layer is connected).

[0025] The negative electrode layer (second electrode layer 12 or first electrode layer 11) of the laminate 14 of the battery body 10 contains a negative electrode active material, a conductive additive, and a solid electrolyte. The solid electrolyte of the negative electrode layer is an oxide solid electrolyte or a sulfide solid electrolyte, for example, the same type of material as the solid electrolyte used in the electrolyte layer 13. The negative electrode active material of the negative electrode layer is, for example, TiO2 (titanium oxide), Nb2O5 (niobium pentoxide), or the like. Other negative electrode active materials of the negative electrode layer include Li3V2(PO4)3 (lithium vanadium phosphate), Li4Ti5O 12 (lithium titanate) or the like may be used. The conductive additive for the negative electrode layer may be, for example, a carbon material such as carbon fiber, carbon black, graphite, graphene, or carbon nanotubes, or a conductive material such as iron silicide. The negative electrode layer is connected to either the external connection terminal 20 or the external connection terminal 30 (the terminal different from the one to which the positive electrode layer is connected).

[0026] In the solid-state battery 1, during charging, lithium ions are conducted and taken up from the positive electrode layer (first electrode layer 11 or second electrode layer 12) to the negative electrode layer (second electrode layer 12 or first electrode layer 11) via the electrolyte layer 13, and during discharging, lithium ions are conducted and taken up from the negative electrode layer to the positive electrode layer via the electrolyte layer 13. In the solid-state battery 1, charge and discharge operations are realized by such lithium ion conduction.

[0027] The insulating layer 15 of the battery body 10 is made of various insulating materials. The insulating properties of the insulating material used for the insulating layer 15 refer to the property of having no or sufficiently low influence on lithium ion conduction and electronic conduction in the laminate 14. For example, the insulating layer 15 is made of an insulating material having lower electronic conductivity than the first electrode layer 11 and the second electrode layer 12. The insulating layer 15 is preferably made of a material that has low moisture and gas permeability and good sealing properties. Among these, it is preferable to use a material for the insulating layer 15 that has a linear expansion coefficient similar to that of each layer constituting the laminate 14 of the battery body 10 and that has good adhesion to each layer. Examples of insulating materials that can be used for the insulating layer 15 include glass, ceramics, and solid electrolytes.

[0028] An external connection terminal 20 and an external connection terminal 30 are provided on the end face 10a and the end face 10b of the battery body 10, respectively. The external connection terminal 20 is connected to a part of the first electrode layer 11 exposed from the insulating layer 15 at the end face 10a of the battery body 10. The external connection terminal 30 is connected to a part of the second electrode layer 12 exposed from the insulating layer 15 at the end face 10b of the battery body 10.

[0029] As shown in FIG. 3 , the external connection terminal 20 includes a conductive layer 41, a metal film 22, and a metal film 23. The conductive layer 41 covers the end face 10 a and extends from the end face 10 a to a portion of the outer surface 10 c that is continuous with the end face 10 a. The metal film 22 is provided to cover the conductive layer 41, and the metal film 23 is provided to cover the metal film 22. The conductive layer 41 is an example of an inner layer of the external connection terminal 20, and the metal films 22 and 23 are examples of outer layers of the external connection terminal 20. As shown in FIG. 3 , the external connection terminal 30 includes a conductive layer 42, a metal film 32, and a metal film 33. The conductive layer 42 covers the end face 10 b and extends from the end face 10 b to a portion of the outer surface 10 c that is continuous with the end face 10 b. The metal film 32 is provided to cover the conductive layer 42, and the metal film 33 is provided to cover the metal film 32. The conductive layer 42 is an example of an inner layer of the external connection terminal 30 , and the metal film 32 and the metal film 33 are an example of an outer layer of the external connection terminal 30 .

[0030] As shown in Fig. 3, the conductive layer 41 and the conductive layer 42 are provided on the end face 10a side and the end face 10b side of the outer surface 10c of the battery body 10, respectively. As shown in Fig. 3, the conductive layer 41 and the conductive layer 42 are directly connected to the first electrode layer 11 and the second electrode layer 12 of the battery body 10, respectively. Note that, as shown in Figs. 3 and 4, the conductive layer 41 and the conductive layer 42 are not provided in the center between the end on the end face 10a side and the end on the end face 10b side of the battery body 10.

[0031] 5, of the outer surfaces 10c of the battery body 10, the outer surface 10c facing the first side (upper side of the paper) in the first direction D1 is also referred to as the "upper surface" 10c1, and the outer surface 10c facing the second side (lower side of the paper) opposite the first side in the first direction D1 is also referred to as the "lower surface" 10c2. Furthermore, the upper surface 10c1 and the lower surface 10c2, which are the outer surfaces 10c facing the first direction D1, are also referred to as the "upper and lower surfaces." Furthermore, of the outer surfaces 10c of the battery body 10, the opposing outer surfaces 10c facing the third direction D3 are also referred to as the "side surface" 10c3.

[0032] 3 and 5, the conductive layer 41 is provided on the outer surface 10c of the battery body 10 facing the first direction D1 and the third direction D3, i.e., on the upper surface 10c1 and lower surface 10c2 (top and bottom surfaces) and side surface 10c3 of the battery body 10. Metal films 22 and 23 are provided on the outside of the conductive layer 41 thus provided. Note that while FIG. 5 illustrates the conductive layer 41, metal film 22, and metal film 23 on one end face 10a side, the conductive layer 42, metal film 32, and metal film 33 on the other end face 10b side have the same configuration.

[0033] The conductive layers 41 and 42 contain a conductive material and an insulating material, and are layers that exhibit conductivity due to the conductive material. The conductive material of the conductive layers 41 and 42 can be a conductive material containing carbon. For example, the conductive material of the conductive layers 41 and 42 can be a material containing powder such as vapor grown carbon fiber (VGCF). The conductive layers 41 and 42 do not contain components such as Ag, which are relatively susceptible to migration, as their main component. The ratio of the conductive material to the insulating material is adjusted so that the conductive layers 41 and 42 exhibit a predetermined conductivity.

[0034] In addition to a predetermined conductivity, the conductive layers 41 and 42 preferably have low moisture and gas permeability and good sealing properties. To obtain such properties, the conductive layers 41 and 42 contain a predetermined insulating material together with a conductive material. The insulating material contained in the conductive layers 41 and 42 together with the conductive material can be an insulating material containing glass.

[0035] Metal films 22 and 32 can be made of a metal material such as Ni. Metal films 23 and 33 can be made of a metal material such as Sn. Metal films 22 and 23, and metal films 32 and 33, enable relatively easy mounting of solid-state battery 1 on other electronic components such as a circuit board. Metal films 22 and 23 covering conductive layer 41, and metal films 32 and 33 covering conductive layer 42, have relatively high barrier properties against moisture, and can therefore function as protective films for protecting conductive layers 41 and 42 from external moisture.

[0036] 3 to 5, the conductive layer 41 (inner layer) provided to cover the end face 10a and part of the outer surface 10c of the battery body 10 is further covered with the metal film 22 and the metal film 23 (outer layer). Similarly, in the solid-state battery 1 shown in Figures 3 to 5, the conductive layer 42 (inner layer) provided to cover the end face 10b and part of the outer surface 10c of the battery body 10 is further covered with the metal film 32 and the metal film 33 (outer layer).

[0037] As described above, conductive layers 41 and 42 are made of a conductive material containing carbon, and do not contain components such as Ag, which are relatively susceptible to migration, as their main component. Furthermore, metal films 22 and 23, as well as metal films 32 and 33, have moisture barrier properties. Therefore, external moisture is prevented from penetrating into conductive layer 41, the inner layer of external connection terminal 20, and conductive layer 42, the inner layer of external connection terminal 30. Even if moisture penetrates into conductive layer 41 and conductive layer 42, migration of components of the conductive material contained in conductive layer 41 and conductive layer 42 is prevented. That is, migration of components such as Ag is prevented from occurring in conductive layers 41 and 42, which do not contain components such as Ag as their main component.

[0038] According to the configurations shown in FIGS. 3 to 5, migration of components such as Ag from the inner layers of the external connection terminals 20 and 30 is suppressed, and performance degradation such as short circuits caused by such migration is suppressed, thereby realizing a high-performance solid-state battery 1.

[0039] The solid state battery 1 shown in FIGS. 3 to 5 is manufactured, for example, by the following method. 6A and 6B are diagrams illustrating an example of a method for manufacturing a solid-state battery according to the first embodiment. Fig. 6A is a schematic cross-sectional view of a main part of an example of a battery body forming step. Fig. 6B is a schematic cross-sectional view of a main part of an example of a conductive layer forming step.

[0040] <Battery body formation process> First, a battery body 10 is formed as shown in FIG. 6(A). In forming the battery body 10, pastes for forming the electrode layers, that is, the first electrode layer 11 and the second electrode layer 12, the electrolyte layer 13, and the insulating layer 15, are prepared in advance. One of the first electrode layer 11 and the second electrode layer 12 is a positive electrode layer, and the other is a negative electrode layer. Here, the paste for forming the positive electrode layer is also referred to as "positive electrode paste," and the paste for forming the negative electrode layer is also referred to as "negative electrode paste." The paste for forming the electrolyte layer 13 is also referred to as "electrolyte paste." The paste for forming the insulating layer 15 is also referred to as "insulating paste."

[0041] [Preparation of positive electrode paste] For example, 11.3 parts by mass of LCPO powder was used as the positive electrode active material, and amorphous Li was used as the solid electrolyte. 1.5 Al 0.5 Ge 1.5 The mixture contains 16.7 parts by weight of (PO4)3 powder (also known as "LAGPg powder"), 5.5 parts by weight of VGCF powder as a conductive additive, 7.8 parts by weight of polyvinyl butyral as a binder, 0.3 parts by weight of triethylene glycol bis(2-ethylhexanoate) as a plasticizer, 0.6 parts by weight of a specified dispersant, and 57.8 parts by weight of terpineol as a diluent. These ingredients are mixed in a ball mill for 72 hours, then mixed and dispersed in a three-roll mill. A particle gauge is used to disperse the material aggregates to 1 μm or less, yielding a positive electrode paste. The positive electrode paste is used to form the positive electrode layer (first electrode layer 11 or second electrode layer 12).

[0042] [Preparation of negative electrode paste] For example, a negative electrode paste is prepared in the same manner as the positive electrode paste, except that the same amount of TiO2 is used as the negative electrode active material instead of the positive electrode active material. The negative electrode paste is used to form a negative electrode layer (second electrode layer 12 or first electrode layer 11).

[0043] [Preparation of Electrolyte Paste] For example, 29.0 parts by mass of LAGPg powder as a solid electrolyte and crystalline Li 1.5 Al 0.5 Ge 1.5The mixture contains 3.2 parts by weight of (PO4)3 powder (also known as "LAGPc powder"), 6.2 parts by weight of polyvinyl butyral as a binder, 2.2 parts by weight of triethylene glycol bis(2-ethylhexanoate) as a plasticizer, 0.3 parts by weight of a specified dispersant, and 59.1 parts by weight of terpineol as a diluent. After mixing these ingredients in a ball mill for 72 hours, the mixture is mixed and dispersed in a three-roll mill and dispersed using a particle gauge until the material aggregates are 1 μm or less, resulting in an electrolyte paste. This electrolyte paste is used to form the electrolyte layer 13.

[0044] [Preparation of insulating paste] For example, an insulating paste is obtained in the same manner as the electrolyte paste, except that a powder of glass or ceramic, or both, is used as the insulating material instead of the LAGPg powder and LAGPc powder in the electrolyte paste. The insulating paste is used to form the insulating layer 15.

[0045] Glasses used in insulating pastes include those containing Sn, B (boron), Al (aluminum), Ba (barium), Zn (zinc), Si (silicon), Bi (bismuth), P (phosphorus), Na (sodium), Ca (calcium), F (fluorine), V (vanadium), Zr (zirconium), etc. Examples of glasses used in insulating pastes include SnO-B2O3-P2O5-Al2O3, SiO2-B2O3-BaO-ZnO, SiO2-B2O3-Bi2O3-ZnO, ZnO-Bi2O3-B2O3, SiO2-Bi2O3, B2O3-P2O5-Na2O-CaO-BaO-Al2O3, SnO-P2O5, SnO-B2O3-P2O5, SiO2-SnO-P2O5, Examples include SiO2-B2O3-R2O, SiO2-B2O3-ZnO-Na2O-NaF-V2O5, SnO-ZnO-P2O5-R2O-R2O, SiO2-B2O3-ZnO, SiO2-B2O3-Al2O3-ZrO2, SiO2-B2O3-ZnO-R2O-R2O, SiO2-B2O3-Al2O3-R2O-R2O (R is an alkali metal, R is an alkaline earth metal), etc.

[0046] Examples of ceramics used in the insulating paste include alumina, ferrite, zirconia, zircon, barium zirconate, calcium zirconate, titanium oxide, barium titanate, strontium titanate, calcium titanate, magnesium titanate, zinc titanate, lanthanum titanate, neodymium titanate, lead zirconate titanate, alumina nitride, silicon nitride, boron nitride, boron carbide, barium stannate, calcium stannate, magnesium silicate, mullite, steatite, cordierite, and forsterite.

[0047] In addition, a solid electrolyte may be used in place of or in addition to the glass or ceramics in the insulating paste. [Fabrication of Battery Body] A pattern of insulating paste is printed on a portion of a polyethylene terephthalate (PET) film using a screen printing method, and then dried, for example, at 90°C for 10 minutes. The printing and drying of the insulating paste may be repeated multiple times until the desired thickness is achieved. This produces an insulating mixture layer part in which an insulating mixture layer formed from the insulating paste is provided on the PET film.

[0048] A pattern of electrolyte paste is printed on a portion of another PET film by screen printing, and then dried, for example, at 90°C for 10 minutes. Printing and drying of the electrolyte paste may be repeated multiple times until a predetermined thickness is achieved. This produces an electrolyte mixture layer part in which an electrolyte mixture layer formed from the electrolyte paste is provided on the PET film.

[0049] A positive electrode paste is pattern-printed on the electrolyte mixture layer of the electrolyte mixture layer part by screen printing, and then dried, for example, at 90°C for 10 minutes. Next, an insulating paste is pattern-printed on the outside of the pattern-printed positive electrode paste by screen printing, and then dried, for example, at 90°C for 10 minutes. The printing and drying of the positive electrode paste and the printing and drying of the insulating paste may be repeated multiple times until a predetermined thickness is achieved. This produces a positive electrode mixture layer part in which a positive electrode mixture layer formed from the positive electrode paste and an insulating mixture layer formed from the insulating paste are provided on the electrolyte mixture layer part.

[0050] The negative electrode mixture layer part is fabricated in the same manner as the fabrication of the positive electrode mixture layer part, except that a negative electrode paste is used instead of the positive electrode paste. That is, the negative electrode mixture layer part is fabricated by providing a negative electrode mixture layer formed from the negative electrode paste and an insulating mixture layer formed from the insulating paste on an electrolyte mixture layer part.

[0051] The insulating mixture layer part, electrolyte mixture layer part, positive electrode mixture layer part, and negative electrode mixture layer part are also referred to simply as "parts." The insulating mixture layer, electrolyte mixture layer, positive electrode mixture layer, and negative electrode mixture layer included in these parts are also referred to simply as "mixture layers."

[0052] After the above-mentioned parts are produced, for example, the electrolyte mixture layer of the electrolyte mixture layer part is transferred onto the insulating mixture layer of the insulating mixture layer part by thermocompression bonding. The positive electrode mixture layer (or negative electrode mixture layer) and insulating mixture layer of the positive electrode mixture layer part (or negative electrode mixture layer part) are transferred onto the insulating mixture layer by thermocompression bonding. Then, the negative electrode mixture layer (or positive electrode mixture layer) and insulating mixture layer of the negative electrode mixture layer part (or positive electrode mixture layer part) are transferred onto the electrolyte mixture layer provided on the opposite side of the positive electrode mixture layer (or negative electrode mixture layer) and insulating mixture layer by thermocompression bonding. This transfer of the positive electrode mixture layer part (or negative electrode mixture layer part) and the negative electrode mixture layer part (or positive electrode mixture layer part) is repeated until a predetermined number of layers are stacked. Thereafter, the insulating mixture layer of the insulating mixture layer part is similarly stacked and transferred by thermocompression bonding. The conditions for the thermocompression bonding are, for example, a pressure of 20 MPa and a temperature of 70°C.

[0053] The structure thus obtained is processed by cutting or the like to have predetermined planar dimensions, for example, 4.5 mm × 3.2 mm. During processing, of the portions that will become both end faces (end faces 10a and 10b) of the battery body 10 in the second direction D2, processing is performed so that a portion (side face) of the positive electrode mixture layer is exposed on one end face and a portion (side face) of the negative electrode mixture layer is exposed on the other end face opposite the one end face. When the positive electrode mixture layer part and the negative electrode mixture layer part are transferred as described above, the stacking positions of the positive electrode mixture layer and the negative electrode mixture layer (the formation of their overlapping regions) are adjusted so that a portion of the positive electrode mixture layer can be exposed on one end face and a portion of the negative electrode mixture layer can be exposed on the other end face. After processing, the end face where a portion of the positive electrode mixture layer is exposed becomes the positive electrode pull-out surface, and the other end face where a portion of the negative electrode mixture layer is exposed becomes the negative electrode pull-out surface.

[0054] The structure thus processed is placed flat on a porous ceramic plate and heated, for example, in an air atmosphere at a temperature in the range of 480°C to 520°C for 2 to 10 hours to remove organic components contained in the structure, such as binders, plasticizers, dispersants, etc. Further, the structure is heated, for example, in a nitrogen atmosphere at a temperature in the range of 600°C to 650°C for 2 to 10 hours to sinter the solid electrolyte, glass, ceramics, etc. contained in the structure.

[0055] This results in the production of a battery body 10 as shown in Fig. 6(A). The electrolyte mixture layer contained in the produced battery body 10 forms the electrolyte layer 13. One of the positive electrode mixture layer and the negative electrode mixture layer contained in the produced battery body 10 forms the first electrode layer 11, and the other forms the second electrode layer 12. The positive electrode mixture layer, the negative electrode mixture layer, and the electrolyte mixture layer interposed therebetween form a laminate 14. The insulating mixture layer contained in the produced battery body 10 forms the insulating layer 15.

[0056] That is, by the above method, a battery body 10 is formed, which has a laminate 14 including a first electrode layer 11 and a second electrode layer 12 stacked in a first direction D1 (a direction perpendicular to the second direction D2 and the third direction D3) and an electrolyte layer 13 therebetween, and an insulating layer 15 covering the laminate 14. The battery body 10 is formed so as to have an end face 10a facing one side in a second direction D2 perpendicular to the first direction D1, where a portion of the first electrode layer 11 is exposed from the insulating layer 15, and an end face 10b facing the other side in the second direction D2, where a portion of the second electrode layer 12 is exposed from the insulating layer 15. The process of forming the battery body 10 includes a step of stacking pastes for forming the first electrode layer 11, the second electrode layer 12, the electrolyte layer 13, and the insulating layer 15 (or parts made using the pastes, or mixture layers included in the parts) and co-firing them to form the first electrode layer 11, the second electrode layer 12, the electrolyte layer 13, and the insulating layer 15, respectively.

[0057] <Conductive layer formation process> After the battery body 10 is formed as shown in FIG. 6(A), conductive layers 41 and 42 are formed in predetermined locations on the battery body 10 as shown in FIG. 6(B). The conductive layer 41 covers the end face 10a of the battery body 10, is connected to a portion of the first electrode layer 11 exposed at the end face 10a, and extends from the end face 10a to a portion of the outer surface 10c. The conductive layer 42 covers the end face 10b of the battery body 10, is connected to a portion of the second electrode layer 12 exposed at the end face 10b, and extends from the end face 10b to a portion of the outer surface 10c. In forming the conductive layers 41 and 42, a paste for forming the conductive layers 41 and 42 is prepared in advance. Here, the paste for forming the conductive layers 41 and 42 is also referred to as a "conductive paste."

[0058] [Preparation of conductive paste] For example, a conductive paste is obtained in the same manner as the preparation of the electrolyte paste, except that a conductive material containing carbon and an insulating material containing glass are used instead of the LAGPg powder and LAGPc powder of the electrolyte paste. Carbon such as VGCF is used as the conductive material of the conductive paste. Glass, as described above for preparing the insulating paste, is used as the insulating material of the conductive paste. For example, a conductive paste is obtained using such conductive and insulating materials. The conductive paste is used to form conductive layers 41 and 42. The ratio of the conductive material to the insulating material in the conductive paste, etc., is adjusted so that the conductive mixture layer formed from the conductive paste (or the conductive layers 41 and 42 formed from the conductive mixture layer) exhibits a predetermined conductivity.

[0059] [Preparation of Conductive Layer] The conductive layer 41 is formed by applying a conductive paste to the end face 10a and a portion of the outer surface 10c of the battery body 10 (the end on the end face 10a side) and then performing a heat treatment. For example, the end of the battery body 10 on the end face 10a side is dipped in the conductive paste, thereby applying the conductive paste to the end face 10a and a portion of the outer surface 10c. Alternatively, the conductive paste is pattern-printed on the end of the battery body 10 on the end face 10a side, thereby applying the conductive paste to the end face 10a and a portion of the outer surface 10c. The conductive paste applied by a predetermined method such as dipping or pattern printing is then subjected to a heat treatment for drying, hardening, and baking, thereby forming the conductive layer 41 as shown in FIG. 6(B) from the conductive paste.

[0060] Similarly, the conductive layer 42 is formed by applying a conductive paste to the end face 10b and a portion of the outer surface 10c of the battery body 10 (the end on the end face 10b side) and then performing a heat treatment. For example, the end of the battery body 10 on the end face 10b side is dipped in the conductive paste, thereby applying the conductive paste to the end face 10b and a portion of the outer surface 10c. Alternatively, the conductive paste is pattern-printed on the end of the battery body 10 on the end face 10b side, thereby applying the conductive paste to the end face 10b and a portion of the outer surface 10c. The conductive paste applied by a predetermined method such as dipping or pattern printing is then subjected to a heat treatment for drying, hardening, and baking, thereby forming the conductive layer 42 from the conductive paste as shown in FIG. 6(B).

[0061] <Metal film formation process> After the conductive layers 41 and 42 are formed as shown in FIG. 6(B), metal films 22 and 23 covering the conductive layer 41, and metal films 32 and 33 covering the conductive layer 42, are formed as shown in FIG. 3 and other figures. The metal films 22 and 32 are formed by depositing a metal material such as Ni on the surfaces of the conductive layers 41 and 42 using a plating method. The metal films 23 and 33 are formed by depositing a metal material such as Sn on the surfaces of the metal films 22 and 32 using a plating method. The ratio of the conductive material contained in the conductive layer 41 is adjusted so that the conductive layer 41 has a conductivity sufficient to allow the metal films 22 and 23 to be deposited thereon using a plating method. The ratio of the conductive material contained in the conductive layer 42 is adjusted so that the conductive layer 42 has a conductivity sufficient to allow the metal films 32 and 33 to be deposited thereon using a plating method.

[0062] In this manner, metal films 22 and 23 covering conductive layer 41, and metal films 32 and 33 covering conductive layer 42 are formed, thereby producing solid state battery 1 having the configuration shown in Figures 3 to 5 above.

[0063] [Second embodiment] 7 and 8 are diagrams illustrating an example of the configuration of a solid-state battery according to the second embodiment. Each of FIGS. 7 and 8 shows a cross-sectional view of a main part of the example of the configuration of a solid-state battery according to the second embodiment. Here, FIG. 7 is a cross-sectional view taken along line L1 in FIG. 1 when the example of the configuration of a solid-state battery according to the second embodiment is employed. FIG. 8 is a cross-sectional view taken along line L3 in FIGS. 1 and 7 when the example of the configuration of a solid-state battery according to the second embodiment is employed.

[0064] 7 and 8 has a configuration in which an external electrode layer 21 is provided between a conductive layer 41 and a metal film 22, and an external electrode layer 31 is provided between the conductive layer 42 and a metal film 32. The external electrode layer 21 and the external electrode layer 31 are made of a material containing a conductive component such as Ag.

[0065] The solid-state battery 1 shown in Figures 7 and 8 includes, as the external connection terminal 20, a conductive layer 41, an external electrode layer 21, a metal film 22, and a metal film 23. The conductive layer 41 and the external electrode layer 21 are examples of inner layers of the external connection terminal 20, and the metal film 22 and the metal film 23 are examples of outer layers of the external connection terminal 20. The solid-state battery 1 shown in Figures 7 and 8 also includes, as the external connection terminal 30, a conductive layer 42, an external electrode layer 31, a metal film 32, and a metal film 33. The conductive layer 42 and the external electrode layer 31 are examples of inner layers of the external connection terminal 30, and the metal film 32 and the metal film 33 are examples of outer layers of the external connection terminal 30.

[0066] 7 and 8, the external electrode layer 21 is provided on the outer surface 10c of the battery body 10 facing the first direction D1 and the third direction D3, i.e., on the outside of the conductive layer 41 on the upper surface 10c1, lower surface 10c2, and side surface 10c3 of the battery body 10. Metal films 22 and 23 are provided on the outside of the external electrode layer 21 provided in this manner. Note that while FIG. 8 illustrates the conductive layer 41, external electrode layer 21, metal film 22, and metal film 23 on one end face 10a side, the conductive layer 42, external electrode layer 31, metal film 32, and metal film 33 on the other end face 10b side have the same configuration.

[0067] 7, the conductive layer 41 on the end face 10a side is provided so as to extend outward beyond the edge 21a of the external electrode layer 21, with a portion covered by the external electrode layer 21 and another portion not covered by (exposed from) the external electrode layer 21. Then, as shown in Figures 7 and 8, the metal film 22 and the metal film 23 are provided so as to cover the external electrode layer 21 and the portion of the conductive layer 41 that is not covered by the external electrode layer 21 and extends outward from the edge 21a.

[0068] Similarly, the conductive layer 42 on the end face 10b side is provided so as to extend outward beyond the edge 31a of the external electrode layer 31, with a portion covered by the external electrode layer 31 and another portion not covered by (exposed from) the external electrode layer 31, as shown in Fig. 7. Then, as shown in Fig. 7, the metal film 32 and the metal film 33 are provided so as to cover the external electrode layer 31 and the portion of the conductive layer 42 that is not covered by the external electrode layer 31 and extends outward from the edge 31a.

[0069] The solid state battery 1 shown in FIGS. 7 and 8 differs from those shown in FIGS. 3 to 5 above in that it has such a configuration. 7 and 8, the conductive layer 41 underlying the external electrode layer 21 is provided so as to extend outward beyond the edge 21a of the external electrode layer 21, and the metal films 22 and 23 are provided so as to cover the external electrode layer 21 and the portion of the conductive layer 41 outside the edge 21a. Thus, the external electrode layer 21 is sufficiently covered by the metal films 22 and 23, and exposure of parts such as the edge 21a from the metal films 22 and 23 is prevented. Similarly, in the solid-state battery 1 shown in FIGS. 7 and 8, the conductive layer 42 underlying the external electrode layer 31 is provided so as to extend outward beyond the edge 31a of the external electrode layer 31, and the metal films 32 and 33 are provided so as to cover the external electrode layer 31 and the portion of the conductive layer 42 outside the edge 31a. Therefore, the external electrode layer 31 is sufficiently covered with the metal film 32 and the metal film 33, and the edges 31a and the like are prevented from being partially exposed from the metal film 32 and the metal film 33.

[0070] As described above, the conductive layer 41, the metal film 22, and the metal film 23, as well as the conductive layer 42, the metal film 32, and the metal film 33, have barrier properties against moisture. Therefore, the barrier properties of the conductive layer 41, the metal film 22, and the metal film 23 suppress reaction between the external electrode layer 21 and external moisture, thereby suppressing migration of components such as Ag contained in the external electrode layer 21, which is part of the inner layer of the external connection terminal 20. Similarly, the barrier properties of the conductive layer 42, the metal film 32, and the metal film 33 suppress reaction between the external electrode layer 31 and external moisture, thereby suppressing migration of components such as Ag contained in the external electrode layer 31, which is part of the inner layer of the external connection terminal 30.

[0071] According to the configurations shown in FIGS. 7 and 8, migration of components such as Ag from the inner layers of the external connection terminals 20 and 30 is suppressed, and performance degradation such as short circuits caused by such migration is suppressed, thereby realizing a high-performance solid-state battery 1.

[0072] The solid state battery 1 shown in FIGS. 7 and 8 is manufactured, for example, by the following method. 9A and 9B are diagrams illustrating an example of a method for manufacturing a solid-state battery according to the second embodiment. Fig. 9A is a schematic cross-sectional view of a main part of an example of a battery body and conductive layer forming step. Fig. 9B is a schematic cross-sectional view of a main part of an example of an external electrode layer forming step.

[0073] <Battery body and conductive layer formation process> 7 and 8, the battery body 10 is formed according to the example described above with reference to Fig. 6(A), and then the conductive layer 41 and the conductive layer 42 are formed according to the example described above with reference to Fig. 6(B). This results in a structure as shown in Fig. 9(A), i.e., a structure in which the conductive layer 41 is provided on the end face 10a and part of the outer face 10c of the battery body 10, and the conductive layer 42 is provided on the end face 10b and part of the outer face 10c of the battery body 10.

[0074] <External electrode layer formation process> After forming the battery body 10 and the conductive layers 41 and 42 as shown in Fig. 9(A), the external electrode layers 21 and 31 are formed at predetermined locations on the conductive layers 41 and 42, respectively, as shown in Fig. 9(B). In forming the external electrode layers 21 and 31, a paste for forming the external electrode layers 21 and 31 is prepared in advance. Here, the paste for forming the external electrode layers 21 and 31 is also referred to as "external electrode paste." For example, a material containing a conductive component such as Ag is prepared as the external electrode paste.

[0075] The external electrode layer 21 is formed by applying an external electrode paste to the outside of the conductive layer 41 and then subjecting it to a heat treatment. For example, the conductive layer 41 provided on the end surface 10a side of the battery body 10 is dipped into the external electrode paste to apply the external electrode paste to the outside of the conductive layer 41. Alternatively, the external electrode paste is applied to the outside of the conductive layer 41 provided on the end surface 10a side of the battery body 10 by pattern-printing the external electrode paste on the conductive layer 41. When applying the external electrode paste to the outside of the conductive layer 41 by a predetermined method such as dipping or pattern printing, the external electrode paste is applied so that the conductive layer 41 extends outward beyond the edge 21a of the external electrode layer 21, i.e., so that a portion of the conductive layer 41 is exposed from the external electrode layer 21. The external electrode paste applied by a predetermined method is subjected to heat treatment for drying, hardening, and baking, and the external electrode layer 21 as shown in FIG. 9(B) is formed from the external electrode paste.

[0076] Similarly, the external electrode layer 31 is formed by applying an external electrode paste to the outside of the conductive layer 42 and then subjecting it to a heat treatment. For example, the conductive layer 42 provided on the end surface 10a of the battery body 10 is dipped into the external electrode paste to apply the external electrode paste to the outside of the conductive layer 42. Alternatively, the external electrode paste is applied to the outside of the conductive layer 42 by pattern-printing the external electrode paste on the conductive layer 42 provided on the end surface 10a of the battery body 10. When applying the external electrode paste to the outside of the conductive layer 42 by a predetermined method such as dipping or pattern printing, the external electrode paste is applied so that the conductive layer 42 extends outward beyond the edge 31a of the external electrode layer 31, i.e., so that a portion of the conductive layer 42 is exposed from the external electrode layer 31. The external electrode paste applied by a predetermined method is subjected to heat treatment for drying, hardening, and baking, and the external electrode layer 31 as shown in FIG. 9(B) is formed from the external electrode paste.

[0077] <Metal film formation process> After the external electrode layer 21 and the external electrode layer 31 are formed as shown in FIG. 9(B), the metal films 22 and 23, and the metal films 32 and 33 are formed as shown in FIG. 7 and the like. For example, Ni films are formed as the metal films 22 and 32 using a plating method. For example, Sn films are formed as the metal films 23 and 33 using a plating method. The metal films 22 and 23 are formed not only on the surface of the external electrode layer 21 but also on the surface of the conductive layer 41 exposed from the external electrode layer 21 and extending outward from its edge 21a. Similarly, the metal films 32 and 33 are formed not only on the surface of the external electrode layer 31 but also on the surface of the conductive layer 42 exposed from the external electrode layer 31 and extending outward from its edge 31a.

[0078] In this manner, the metal films 22 and 23 that cover the external electrode layer 21 and a portion of the conductive layer 41, and the metal films 32 and 33 that cover the external electrode layer 31 and a portion of the conductive layer 42 are formed, thereby manufacturing a solid state battery 1 having the configuration shown in Figures 7 and 8 above.

[0079] [Third embodiment] In the solid state batteries 1 according to the first and second embodiments, the configuration of the battery body 10 is not limited to the above-described examples. Here, another configuration example of the battery body 10 will be described as a third embodiment.

[0080] 10A to 10C are diagrams illustrating an example of the configuration of a battery body according to a third embodiment. Each of Fig. 10A to Fig. 10C is a schematic cross-sectional view of a main part of the example of the configuration of the battery body. Each of Fig. 10A to Fig. 10C is a schematic cross-sectional view taken along line L2 in Fig. 1.

[0081] The battery body 10 may be modified from the above-described exemplary configurations (FIGS. 3 to 9) to, for example, the configurations shown in FIGS. 10(A) to 10(C). That is, the battery body 10 may be configured in such a way that the stacking order of the first electrode layer 11 and the second electrode layer 12 is reversed, as shown in FIG. 10(A). Furthermore, the battery body 10 may be configured in such a way that the width of the second electrode layer 12 in the third direction D3 is greater than the width of the first electrode layer 11 in the third direction D3, as shown in FIG. 10(B). Furthermore, the battery body 10 may be configured in such a way that the width of the first electrode layer 11 in the third direction D3 is greater than the width of the second electrode layer 12 in the third direction D3, as shown in FIG. 10(C).

[0082] As another example of the configuration of the solid state battery 1 according to the first embodiment, it is also possible to obtain a battery having a battery body 10 having any of the configurations shown in Figures 10(A) to 10(C). Also, as another example of the configuration of the solid state battery 1 according to the second embodiment, it is also possible to obtain a battery having a battery body 10 having any of the configurations shown in Figures 10(A) to 10(C).

[0083] [Examples and Comparative Examples] Examples and comparative examples will be described below. Example 1 The solid state battery 1 of Example 1 had the appearance as shown in FIG. 1 and the cross-sectional structure as shown in FIGS.

[0084] Example 2 The solid state battery 1 of Example 2 had the appearance as shown in FIG. 1 and the cross-sectional structure as shown in FIGS.

[0085] Comparative Example 1 A solid state battery 1a of Comparative Example 1 had the appearance as shown in FIG. 1 and the cross-sectional structure as shown in FIG.

[0086] 〔evaluation〕 The solid-state battery 1 of Example 1-2 and the solid-state battery 1a of Comparative Example 1 were charged at a constant current of 0.15 mA at a temperature of 85°C and a relative humidity (RH) of 85% until they reached 3.4 V. After reaching 3.4 V, they were charged at a constant voltage of 5 hours. Subsequently, they were discharged at a constant current of 0.03 mA and a cutoff voltage of 0 V at a temperature of 85°C and a relative humidity of 85%. This constitutes one cycle, and a 30-cycle charge-discharge test was conducted. After completing the 30-cycle charge-discharge test, the appearance of the solid-state battery 1 of Example 1-2 and the solid-state battery 1a of Comparative Example 1 was observed under a microscope to evaluate the occurrence of migration. The evaluation results are shown in Table 1.

[0087] [Table 1]

[0088] In Table 1, cases where the occurrence of migration was observed are marked as "present," and cases where the occurrence of migration was not observed are marked as "absent." As can be seen from Table 1, in the solid state battery 1 of Example 1-2 in which the conductive layers 41 and 42 were provided, the occurrence of migration was not observed on any of the upper surface 10c1 and the lower surface 10c2 (top and bottom surfaces) and the side surface 10c3 of the battery body 10. In contrast, in the solid state battery 1a of Comparative Example 1 in which the conductive layers 41 and 42 were not provided, the occurrence of migration was observed on any of the upper surface 10c1 and the lower surface 10c2 (top and bottom surfaces) and the side surface 10c3 of the battery body 10.

[0089] With a configuration like that of the solid-state battery 1 of Example 1-2, i.e., a configuration in which a conductive layer 41 is provided at the end of the battery body 10 on the end face 10a side and is covered with metal films 22 and 23, and a conductive layer 42 is provided at the end of the battery body 10 on the end face 10b side and is covered with metal films 32 and 33, it becomes possible to effectively suppress the occurrence of migration.

[0090] The effect of suppressing the occurrence of migration is not affected by the stacking order or width of the first electrode layer 11 and the second electrode layer 12 in the battery body 10. By providing a conductive layer 41 at the end of the battery body 10 on the end face 10a side and covering it with metal films 22 and 23, and providing a conductive layer 42 at the end of the battery body 10 on the end face 10b side and covering it with metal films 32 and 33, for example, migration can be effectively suppressed even when the battery body 10 has the configuration shown in FIG. 10(A), 10(B), or 10(C). That is, in the battery body 10, the outermost layer in the first direction D1 of the laminate 14 may be either the first electrode layer 11 or the second electrode layer 12. Furthermore, the widths of the first electrode layer 11 and the second electrode layer 12 in the third direction D3 may be the same, or one may be larger than the other. [Explanation of symbols]

[0091] 1, 1a solid battery 10 Battery body 10a, 10b end face 10c external surface 10c1 top surface 10c2 bottom surface 10c3 side 11 First electrode layer 12 Second electrode layer 13 Electrolyte layer 14 Laminate 15 Insulating layer 20, 30 External connection terminal 21, 31 External electrode layer 21a, 31a Edge 22, 23, 32, 33 Metal film 41, 42 Conductive layer 100 Migrations 101 Moisture D1 Direction 1 D2 Direction 2 D3 3rd direction

Claims

1. a battery body including a laminate including electrode layers and electrolyte layers laminated in a first direction and an insulating layer covering the laminate, the battery body having an end surface facing a second direction perpendicular to the first direction, where a portion of the electrode layer is exposed from the insulating layer, and an outer surface continuous with the end surface; a conductive layer covering the end surface, connected to the portion of the electrode layer, and extending from the end surface to the outer surface, the conductive layer including a conductive material containing carbon and an insulating material containing glass, and exhibiting conductivity due to the conductive material; a metal film covering the conductive layer; [0010] A solid-state battery, including:

2. an external electrode layer provided between the conductive layer and the metal film; the conductive layer extends outward beyond the edge of the external electrode layer; The solid-state battery according to claim 1 , wherein the metal film covers the conductive layer and the external electrode layer.

3. 3. The solid-state battery according to claim 1, wherein the conductive layer is provided on the outer surface of the battery body facing the first direction and on the outer surface facing a third direction perpendicular to the first direction and the second direction.

4. forming a battery body having a laminate including electrode layers and electrolyte layers laminated in a first direction and an insulating layer covering the laminate, the battery body having an end surface facing a second direction perpendicular to the first direction and at which a portion of the electrode layer is exposed from the insulating layer, and an outer surface continuous with the end surface; forming a conductive layer covering the end surface, connected to the portion of the electrode layer, and extending from the end surface to the outer surface, the conductive layer including a conductive material containing carbon and an insulating material containing glass, and exhibiting conductivity due to the conductive material; forming a metal film covering the conductive layer; A method for manufacturing a solid-state battery, comprising:

5. 5. The method for manufacturing a solid-state battery according to claim 4, wherein the step of forming the conductive layer includes a step of applying a paste for forming the conductive layer to an area of ​​the battery body extending from the end face to the outer surface.

6. a step of forming an external electrode layer between the conductive layer and the metal film after the step of forming the conductive layer and before the step of forming the metal film, In the step of forming the conductive layer, the conductive layer is formed so as to extend outward beyond an edge of the external electrode layer, The method for manufacturing a solid-state battery according to claim 4 , wherein in the step of forming the metal film, the metal film is formed so as to cover the conductive layer and the external electrode layer.

Images