All-solid-state battery, packaging component, and method for manufacturing all-solid-state battery

Abstract

Provided are an all-solid-state battery, a packaging component, and a method for manufacturing the all-solid-state battery, which can eliminate defects such as cracks and warping. [Solution] The all-solid-state battery comprises a laminate having a substantially rectangular parallelepiped shape, in which a first electrode layer including a first electrode portion and a first marginal portion, and a second electrode layer including a second electrode portion different from the first electrode portion and a second marginal portion are stacked with a solid electrolyte layer sandwiched between them, and on four side surfaces other than the top and bottom surfaces at the ends of the stacking direction of the laminate, the first marginal portions are arranged so as to be exposed to first two side surfaces facing each other, the first electrode portions are extended to second two side surfaces other than the first two side surfaces, the second marginal portions are arranged so as to be exposed to the second two side surfaces, and the second electrode portions are extended to the first two side surfaces.

Description

[Technical Field]

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

[0002] In recent years, secondary batteries have been used in a variety of fields. Secondary batteries using electrolytes have problems such as electrolyte leakage. Therefore, all-solid-state batteries, which have a solid electrolyte and other solid components, are being developed.

[0003] In the field of such all-solid-state batteries, in order to achieve a high energy density, a stacked-type all-solid-state battery has been proposed which includes a laminate in which two or more battery units (also called single cells) each consisting of a positive electrode part, a solid electrolyte layer, and a negative electrode part are stacked and integrated (for example, Patent Documents 1 to 6). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-80812 [Patent Document 2] Japanese Patent Application Laid-Open No. 2014-192041 [Patent Document 3] Japanese Patent Publication No. 2023-35436 [Patent Document 4] Japanese Patent Application Publication No. 2020-115450 [Patent Document 5] Japanese Patent Publication No. 2023-35436 [Patent Document 6] Patent Publication No. 2021-44186 Summary of the Invention [Problem to be solved by the invention]

[0005] Patent Document 1 discloses an internal electrode structure of an all-solid-state battery having a laminated structure similar to that of a multilayer ceramic capacitor. When a positive electrode portion and a negative electrode portion are laminated with a solid electrolyte layer sandwiched between them, a gap occurs in the total thickness between the electrode intersections and non-intersections of the positive and negative electrode portions, resulting in distortion. Because such distortion can cause cracks and short circuits, it is effective to provide a margin around the electrode portion, as in Patent Document 2. According to Patent Document 2, the margin portion has a U-shaped shape in a top view, surrounding three sides of the rectangular electrode portion.

[0006] If there is a mismatch in the shrinkage behavior of the electrode part and the marginal part during heat treatment, problems such as cracks will occur during the sintering process. Various simulations have revealed that if there is even a slight mismatch in thermal shrinkage with the electrode part, the marginal part formed in a U-shape on the outer periphery of the electrode part, as in Patent Document 2, causes internal stress during sintering. In Patent Document 3, the marginal part is also formed in a U-shape, and there are many bends at the boundary with the electrode part, making it easy for cracks to occur due to mismatch in thermal shrinkage during sintering.

[0007] The present invention has been made in view of the above-mentioned problems, and aims to provide an all-solid-state battery, a packaging component, and a method for manufacturing an all-solid-state battery that can eliminate defects such as cracks and warpage. [Means for solving the problem]

[0008] The all-solid-state battery according to the present invention comprises a laminate having a substantially rectangular parallelepiped shape, in which a first electrode layer including a first electrode portion and a first marginal portion and a second electrode layer including a second electrode portion different from the first electrode portion and a second marginal portion are stacked with a solid electrolyte layer sandwiched therebetween, and on four side surfaces other than the top and bottom surfaces at the ends in the stacking direction of the laminate, the first marginal portions are arranged so as to be exposed to first two side surfaces facing each other, the first electrode portions are extended to second two side surfaces other than the first two side surfaces, the second marginal portions are arranged so as to be exposed to the second two side surfaces, and the second electrode portions are extended to the first two side surfaces.

[0009] The all-solid-state battery may have two first external electrodes connected to the first two side surfaces, respectively, and a second external electrode connected to the second two side surfaces.

[0010] In the all-solid-state battery, a first length of the laminate in a direction in which the first two side surfaces face each other may be different from a second length of the laminate in a direction in which the second two side surfaces face each other.

[0011] In the all-solid-state battery, the first length may be 1.1 times or more the second length.

[0012] In the all-solid-state battery, the first electrode portion and the second electrode portion may have a thickness of 1 μm or more and 200 μm or less.

[0013] In the all-solid-state battery, the thickness of the first electrode portion and the second electrode portion may be 0.03 times or more and 200 times or less the thickness of the solid electrolyte layer.

[0014] A packaging component according to the present invention includes a substrate, an all-solid-state battery mounted on the substrate, and an exterior member that insulates the all-solid-state battery from the outside air.

[0015] A method for manufacturing an all-solid-state battery according to the present invention includes a step of firing a laminate having a substantially rectangular parallelepiped shape, in which a first electrode layer including a first electrode portion pattern and a first marginal portion paste and a second electrode layer including a second electrode portion pattern different from the first electrode portion pattern and a second marginal portion paste are stacked with a solid electrolyte layer green sheet sandwiched therebetween, and in which, on four side surfaces other than the top and bottom surfaces in the stacking direction of the laminate, the first marginal portion paste is arranged so as to be exposed to first two side surfaces facing each other, the first electrode portion pattern is extended to second two side surfaces other than the first two side surfaces, the second marginal portion paste is arranged so as to be exposed to the second two side surfaces, and the second electrode portion pattern is extended to the first two side surfaces.

[0016] In the method for producing an all-solid-state battery, the surface of the laminate may be polished before firing. [Effects of the Invention]

[0017] According to the present invention, it is possible to provide an all-solid-state battery, a packaging component, and a method for manufacturing an all-solid-state battery that can eliminate defects such as cracks and warping. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is a schematic cross-sectional view showing the basic structure of an all-solid-state battery. [Figure 2] 1(a) and 1(b) are perspective views of a stacked chip in which a plurality of battery units are stacked. [Figure 3] FIG. 2(b) is a cross-sectional view taken along line AA in FIG. [Figure 4] FIG. 2(b) is a cross-sectional view taken along line BB in FIG. [Figure 5] 1(a) is an enlarged view of a cross section of a first side margin, and FIG. 1(b) is an enlarged view of a cross section of a second side margin. [Figure 6] 1(a) is an enlarged view of a cross section of the first end margin, and FIG. 1(b) is an enlarged view of a cross section of the second end margin. [Figure 7] FIG. 1 is a perspective view of a stacked-type all-solid-state battery. [Figure 8] FIG. 2 is a diagram illustrating a state in which an all-solid-state battery is mounted on a mounting substrate. [Figure 9] FIG. 1 is a cross-sectional view illustrating an example of an all-solid-state battery mounted on a mounting substrate. [Figure 10] FIG. 1 is a perspective view illustrating a package component in which an all-solid-state battery is sealed. [Figure 11] 10(a) and 10(b) are diagrams illustrating package parts. [Figure 12] FIG. 2 is a diagram illustrating a stacked structure. [Figure 13] FIG. 1 is a diagram illustrating a flow of a method for manufacturing an all-solid-state battery. [Figure 14] 1A to 1C are diagrams illustrating a lamination process. [Figure 15]FIG. [Figure 16] FIG. [Figure 17] FIG. [Figure 18] FIG. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, embodiments will be described with reference to the drawings.

[0020] (Embodiment) FIG. 1 is a schematic cross-sectional view showing the basic structure of an all-solid-state battery 100. As illustrated in FIG. 1, the all-solid-state battery 100 has a structure in which a solid electrolyte layer 30 is sandwiched between a positive electrode portion 10 and a negative electrode portion 20. The positive electrode portion 10 is formed on a first main surface of the solid electrolyte layer 30. The negative electrode portion 20 is formed on a second main surface of the solid electrolyte layer 30. For example, the positive electrode portion 10, the negative electrode portion 20, and the solid electrolyte layer 30 are sintered bodies obtained by sintering powder materials.

[0021] The solid electrolyte layer 30 has a NASICON-type crystal structure and is mainly composed of an oxide-based solid electrolyte having ion conductivity. The solid electrolyte of the solid electrolyte layer 30 is, for example, an oxide-based solid electrolyte having lithium ion conductivity. The solid electrolyte is, for example, a phosphate-based solid electrolyte. A phosphate-based solid electrolyte having a NASICON-type crystal structure has high conductivity and is stable in the air. The phosphate-based solid electrolyte is, for example, a phosphate containing lithium. The phosphate is not particularly limited, but examples include composite lithium phosphate salts with Ti (e.g., LiTi2(PO4)3). Alternatively, Ti can be partially or completely substituted with a tetravalent transition metal such as Ge, Sn, Hf, or Zr. Furthermore, to increase the Li content, it may be partially substituted with a trivalent transition metal such as Al, Ga, In, Y, or La. More specifically, for example, Li 1+x Al x Ge 2-x(PO4)3 and Li 1+x Al x Zr 2-x (PO4)3, Li 1+x Al x Ti 2-x (PO4)3, etc. For example, a Li-Al-Ge-PO4 (LAGP) material is preferred, to which the same transition metal as that contained in the phosphate having an olivine crystal structure contained in the positive electrode portion 10 and the negative electrode portion 20 has been added in advance. For example, when the positive electrode portion 10 and the negative electrode portion 20 contain a phosphate containing Co and Li, it is preferred that the solid electrolyte layer 30 contain a Li-Al-Ge-PO4-based material to which Co has been added in advance. In this case, it is possible to obtain the effect of suppressing the elution of the transition metal contained in the electrode active material into the electrolyte. When the positive electrode portion 10 and the negative electrode portion 20 contain a phosphate containing Li and a transition element other than Co, it is preferred that the solid electrolyte layer 30 contain a Li-Al-Ge-PO4-based material to which the transition metal has been added in advance.

[0022] The positive electrode part 10 contains a substance having an olivine-type crystal structure as an electrode active material. The negative electrode part 20 preferably also contains the electrode active material. An example of such an electrode active material is a phosphate containing a transition metal and lithium. The olivine-type crystal structure is a crystal possessed by natural olivine, and can be identified by X-ray diffraction.

[0023] A typical example of an electrode active material with an olivine crystal structure is LiCoPO4, which contains Co. Phosphates in which the transition metal Co is substituted in this chemical formula can also be used. The ratio of Li and PO4 can vary depending on the valence. It is preferable to use Co, Mn, Fe, Ni, etc. as the transition metal.

[0024] An electrode active material having an olivine-type crystal structure acts as a positive electrode active material in the positive electrode part 10. For example, when an electrode active material having an olivine-type crystal structure is contained only in the positive electrode part 10, the electrode active material acts as a positive electrode active material. When an electrode active material having an olivine-type crystal structure is also contained in the negative electrode part 20, the negative electrode part 20 exhibits the effects of increasing the discharge capacity and increasing the operating potential with discharge, which are presumed to be based on the formation of a partial solid solution state with the negative electrode active material, although the mechanism of action is not fully understood.

[0025] When both the positive electrode section 10 and the negative electrode section 20 contain electrode active materials with an olivine crystal structure, the respective electrode active materials preferably contain transition metals that may be the same or different from each other. "May be the same or different from each other" means that the electrode active materials contained in the positive electrode section 10 and the negative electrode section 20 may contain the same type of transition metal or different types of transition metals. The positive electrode section 10 and the negative electrode section 20 may contain only one type of transition metal or two or more types of transition metals. Preferably, the positive electrode section 10 and the negative electrode section 20 contain the same type of transition metal. More preferably, the electrode active materials contained in both electrodes have the same chemical composition. By containing the same type of transition metal or electrode active material with the same composition in the positive electrode section 10 and the negative electrode section 20, the compositional similarity of the two internal electrode layers is enhanced, which has the effect of preventing malfunction and withstanding actual use even if the terminals of the all-solid-state battery 100 are attached in reverse, depending on the application.

[0026] The negative electrode section 20 contains a negative electrode active material. By including a negative electrode active material in only one electrode, it becomes clear that the one electrode functions as a negative electrode and the other electrode functions as a positive electrode. It is also possible to include a material known as a negative electrode active material in both electrodes. Regarding the negative electrode active material of the electrode, reference can be made to conventional secondary battery technology, and examples thereof include compounds such as titanium oxide, lithium titanium composite oxide, lithium titanium composite phosphate, carbon, and lithium vanadium phosphate.

[0027] In the production of the positive electrode part 10 and the negative electrode part 20, in addition to these electrode active materials, a solid electrolyte having ion conductivity and a conductive material (conductive additive) are added. For these components, an internal electrode paste can be obtained by uniformly dispersing a binder and a plasticizer in water or an organic solvent. The conductive additive may contain a carbon material or the like. The conductive additive may contain a metal. Examples of the conductive additive metal include Pd, Ni, Cu, Fe, and alloys containing these. The solid electrolyte contained in the positive electrode part 10 and the negative electrode part 20 may be the same as the main solid electrolyte of the solid electrolyte layer 30, for example.

[0028] 2(a) and 2(b) are perspective views of a laminated chip 60 in which multiple battery units are stacked. FIG. 3 is a cross-sectional view taken along line AA in FIG. 2(a). FIG. 4 is a cross-sectional view taken along line BB in FIG. 2(a). The laminated chip 60 has a generally rectangular parallelepiped shape. The laminated chip 60 has an upper surface F1 and a lower surface F2 at the ends of each layer in the stacking direction, and four side surfaces. The four side surfaces include a first side surface S1 and a second side surface S2 (first two side surfaces) that face each other, and a first end surface E1 and a second end surface E2 (second two side surfaces) that face each other.

[0029] 2(a), 2(b), 3, and 4, the Z-axis direction (first direction) is the stacking direction, and is the direction in which the top surface F1 and bottom surface F2 of the stacked chip 60 face each other. The X-axis direction (second direction) is the direction in which the first end surface E1 and second end surface E2 of the stacked chip 60 face each other. The Y-axis direction (third direction) is the direction in which the first side surface S1 and second side surface S2 face each other. The X-axis direction, Y-axis direction, and Z-axis direction are perpendicular to each other.

[0030] As illustrated in FIG. 2(b), the length (first length) of the stacked chip 60 in the X-axis direction is represented as length L. The width (second length) of the stacked chip 60 in the Y-axis direction is represented as width W. The height of the stacked chip 60 in the Z-axis direction is represented as height H.

[0031] In the following description, components having the same composition range as those in the all-solid-state battery 100 are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0032] In the stacked chip 60, multiple positive electrode units 10 and multiple negative electrode units 20 are alternately stacked with solid electrolyte layers 30 interposed therebetween. Both end edges of the multiple positive electrode units 10 in the X-axis direction are extended to the first end face E1 and second end face E2 of the stacked chip 60, but not to the first side face S1 and second side face S2. Both end edges of the multiple negative electrode units 20 in the Y-axis direction are extended to the first end face S1 and second end face S2 of the stacked chip 60, but not to the first end face E1 and second end face E2. The solid electrolyte layer 30 extends from the first end face E1 to the second end face E2 and further extends from the first side face S1 to the second side face S2. Thus, the stacked chip 60 has a structure in which multiple battery units are stacked.

[0033] A cover layer 50 is laminated on the upper end surface of the laminated portion of the positive electrode section 10, the solid electrolyte layer 30, and the negative electrode section 20. The cover layer 50 contacts the uppermost electrode section (either the positive electrode section 10 or the negative electrode section 20) and also contacts a part of the solid electrolyte layer 30. A cover layer 50 is also laminated on the lower end surface of the laminate. The cover layer 50 contacts the lowermost electrode section (either the positive electrode section 10 or the negative electrode section 20) and also contacts a part of the solid electrolyte layer 30. For example, the cover layer 50 is a sintered body obtained by sintering a powder material.

[0034] 3, the region where the positive electrode part 10 and the negative electrode part 20 face each other is the region where battery capacity is generated. Therefore, this region is referred to as the battery capacity region 70. In other words, the battery capacity region 70 is the region where the electrode parts drawn out to the two end surfaces face each other.

[0035] The region near the first end face E1 where the positive electrode portions 10 face each other without the negative electrode portion 20 interposed therebetween is referred to as the first end margin 81. The region near the second end face E2 where the positive electrode portions 10 face each other without the negative electrode portion 20 interposed therebetween is referred to as the second end margin 82. In other words, the end margin is the region where the electrode portions drawn out to the two end faces face each other without the electrode portions drawn out to the two side faces interposed therebetween. The first end margin 81 and the second end margin 82 are regions that do not contribute to battery capacity.

[0036] As illustrated in Fig. 4, in the laminated chip 60, a region near the first side surface S1 where the negative electrode portions 20 face each other without the positive electrode portion 10 therebetween is referred to as a first side margin 91. Also, a region near the second side surface S2 where the negative electrode portions 20 face each other without the positive electrode portion 10 therebetween is referred to as a second side margin 92. In other words, the side margin is a region where the electrode portions drawn out to the two side surfaces face each other without the electrode portions drawn out to the two end surfaces therebetween. The first side margin 91 and the second side margin 92 are regions that do not produce battery capacity.

[0037] 5(a) is an enlarged view of a cross section of the first side margin 91. In the first side margin 91, the negative electrode portion 20 extends to the first side surface S1, but the positive electrode portion 10 does not extend to the first side surface S1. A positive electrode margin 95a is provided in the same layer as the positive electrode portion 10 and is exposed to the first side surface S1. With this configuration, the step between the battery capacity region 70 and the first side margin 91 is suppressed.

[0038] 5(b) is an enlarged view of a cross section of the second side margin 92. In the second side margin 92, the negative electrode portion 20 extends to the second side surface S2, but the positive electrode portion 10 does not extend to the second side surface S2. A positive electrode margin 95a is provided in the same layer as the positive electrode portion 10 and is exposed to the second side surface S2. This configuration reduces the step between the battery capacity region 70 and the second side margin 92.

[0039] 6(a) is an enlarged view of a cross section of the first end margin 81. In the first end margin 81, the positive electrode portion 10 extends to the first end face E1, but the negative electrode portion 20 does not extend to the first end face E1. A negative electrode margin 95b is provided in the same layer as the negative electrode portion 20 and is exposed to the first end face E1. This configuration reduces the step between the battery capacity region 70 and the first end margin 81.

[0040] 6(b) is an enlarged view of a cross section of the second end margin 82. In the second end margin 82, the positive electrode portion 10 extends to the second end face E2, but the negative electrode portion 20 does not extend to the second end face E2. A negative electrode margin 95b is provided in the same layer as the negative electrode portion 20 and is exposed to the second end face E2. This configuration reduces the step between the battery capacity region 70 and the second end margin 82.

[0041] In this embodiment, one of the positive electrode section 10 and the negative electrode section 20 corresponds to the first electrode section, and the other corresponds to the second electrode section. When the positive electrode section 10 corresponds to the first electrode section, the positive electrode margin section 95a corresponds to the first margin section, and the negative electrode margin section 95b corresponds to the second margin section. When the negative electrode section 20 corresponds to the first electrode section, the negative electrode margin section 95b corresponds to the first margin section, and the positive electrode margin section 95a corresponds to the second margin section.

[0042] The positive electrode margin 95a and the negative electrode margin 95b are not particularly limited as long as they are insulating. For example, the positive electrode margin 95a and the negative electrode margin 95b may have the same composition as the solid electrolyte layer 30. Alternatively, the positive electrode margin 95a and the negative electrode margin 95b may have a different composition from the solid electrolyte layer 30. For example, the positive electrode margin 95a and the negative electrode margin 95b may have the same main component as the solid electrolyte layer 30, and the positive electrode margin 95a and the negative electrode margin 95b may have different additive elements than the additive elements of the solid electrolyte layer 30. Alternatively, the main component of the positive electrode margin portion 95a and the negative electrode margin portion 95b may be the same as the main component of the solid electrolyte layer 30, the additive element of the positive electrode margin portion 95a and the negative electrode margin portion 95b may be the same as the additive element of the solid electrolyte layer 30, and the concentration of the additive element in the positive electrode margin portion 95a and the negative electrode margin portion 95b may be different from the concentration of the additive element in the solid electrolyte layer 30. Alternatively, the main component of the positive electrode margin portion 95a and the negative electrode margin portion 95b may be different from the main component of the solid electrolyte layer 30. Furthermore, the ionic conductivity of the positive electrode margin portion 95a and the negative electrode margin portion 95b may be lower than the ionic conductivity of the solid electrolyte layer 30. For example, when the positive electrode margin portion 95a and the negative electrode margin portion 95b have a composition different from that of the solid electrolyte layer 30, when the XZ cross section or the YZ cross section is observed with a scanning electron microscope (SEM), interfaces are observed between the negative electrode margin portion 95b and the positive electrode margin portion 95a and the solid electrolyte layer 30.

[0043] Furthermore, the positive electrode margin 95a does not contain an electrode active material or has a lower electrode active material concentration than the positive electrode portion 10. Furthermore, the negative electrode margin 95b does not contain an electrode active material or has a lower electrode active material concentration than the negative electrode portion 20. In these cases, when observed with an SEM, an interface is observed between the positive electrode margin 95a and the positive electrode portion 10, and an interface is observed between the negative electrode margin 95b and the negative electrode portion 20.

[0044] For example, the material of the negative electrode marginal portion 95b and the positive electrode marginal portion 95a may be glass, alumina, or the like.

[0045] Fig. 7 is a perspective view of a stacked-type all-solid-state battery 100a. As illustrated in Fig. 7, the all-solid-state battery 100a has a configuration in which first external electrodes 41a, 41b and a second external electrode 42 are provided on a stacked chip 60. Note that Fig. 7 is illustrated upside down, so the upper surface is the lower surface F2 and the lower surface is the upper surface F1.

[0046] The first external electrode 41a is provided in contact with the first end face E1, and the first external electrode 41b is provided in contact with the second end face E2. Therefore, the first external electrode 41a and the first external electrode 41b are connected to each positive electrode portion 10 and function as positive electrode terminals. The second external electrode 42 extends from the first side face S1, via the lower face F2, to the second side face S2 so as to be in contact with the second side face S2. Therefore, the second external electrode 42 is connected to each negative electrode portion 20 and functions as negative electrode terminals.

[0047] The first external electrode 41a may cover the entire first end face E1 or may cover a portion of the first end face E1. The first external electrode 41b may cover the entire second end face E2 or may cover a portion of the second end face E2. The second external electrode 42 may cover the entire first side face S1, the lower face F2, and the second side face S2 or may cover a portion of at least one of the three faces. However, to prevent short circuits, the second external electrode 42 is spaced apart from the first external electrode 41a and the first external electrode 41b.

[0048] FIG. 8 is a diagram showing how the all-solid-state battery 100a is mounted on a mounting substrate 200. As illustrated in FIG. 8, the mounting substrate 200 includes two positive electrode lands 201 for the positive electrode and a negative electrode land 202 for the negative electrode. The first external electrodes 41a, 41b on the lower surface F2 are connected to the positive electrode land 201 via solder 203. The second external electrode 42 on the lower surface F2 is connected to the negative electrode land 202 via solder 204. FIG. 9 is a cross-sectional view illustrating the all-solid-state battery 100a mounted on the mounting substrate 200. In this way, by providing three or more joining points when soldering the external electrodes to the mounting substrate, the strength of adhesion to the mounting substrate can be improved.

[0049] FIG. 10 is a perspective view illustrating a package component 300 in which the all-solid-state battery 100a is sealed. As illustrated in FIG. 10, an exterior member 301 is provided on a mounting substrate 200. The exterior member 301 is provided so as to cover the entire all-solid-state battery 100a exposed on the mounting substrate 200. This isolates the all-solid-state battery 100a from the outside air, and the first end face E1, the second end face E2, the first side face S1, and the second side face S2 of the laminated chip 60 are sealed and not exposed to the outside air. The exterior member 301 is made of an insulating material. The exterior member 301 may be a ceramic case or a molded resin. Furthermore, if there is a gap between the exterior member 301 and the all-solid-state battery 100a, the gap may be an air gap, or a sealing material such as resin may be provided in the gap.

[0050] As illustrated in Fig. 11(a), the exterior member 301 may enclose one all-solid-state battery 100a, or as illustrated in Fig. 11(b), the exterior member 301 may enclose a plurality of all-solid-state batteries 100a.

[0051] Here, the all-solid-state battery 100a according to this embodiment will be summarized. As illustrated in FIG. 12, the above-described stacked chip 60 has a rectangular shape in a plan view along the Z-axis direction and has four sides. A positive electrode margin 95a provided in the same layer as the positive electrode unit 10 in the stacking direction is arranged along first two opposing sides of the four sides in a plan view along the Z-axis direction, and the positive electrode unit 10 is drawn out from second two sides different from the first two sides. A negative electrode margin 95b provided in the same layer as the negative electrode unit 20 in the stacking direction is arranged along second two sides in a plan view along the Z-axis direction, and the negative electrode unit 20 is drawn out from the first two sides. As a result, the positive electrode margin 95a is arranged so as to be exposed to the first side surface S1 and the second side surface S2 (first two side surfaces) that face each other as illustrated in Figure 2(a), the positive electrode portion 10 is extended to the first end surface E1 and the second end surface E2 (second two side surfaces), the negative electrode margin 95b is arranged so as to be exposed to the first end surface E1 and the second end surface E2, and the negative electrode portion 20 is extended to the first side surface S1 and the second side surface S2.

[0052] In addition, in a plan view along the Z-axis direction, the positive electrode portion 10 and the two positive electrode margins 95a form a quadrangle. Because the positive electrode portion 10 and the two positive electrode margins 95a are arranged in the same layer, the layer formed by the positive electrode portion 10 and the positive electrode margins 95a is also referred to as a positive electrode layer. In addition, in a plan view along the Z-axis direction, the negative electrode portion 20 and the two negative electrode margins 95b form a quadrangle. Because the negative electrode portion 20 and the two negative electrode margins 95b are arranged in the same layer, the layer formed by the negative electrode portion 20 and the negative electrode margins 95b is also referred to as a negative electrode layer.

[0053] In a plan view along the Z-axis direction, the four sides of a quadrangle formed by the positive electrode layer overlap with the four sides of a quadrangle formed by the negative electrode layer. In addition, in a plan view, the four sides of a quadrangle formed by the solid electrolyte layer 30 overlap with the four sides of a quadrangle formed by the positive electrode layer and the four sides of a quadrangle formed by the negative electrode layer.

[0054] The first external electrodes 41a, 41b (first terminals) are in contact with the positive electrode portion 10, the solid electrolyte layer 30, and the negative electrode margin portion 95b at the first end face E1 and the second end face E2. The second external electrode 42 (second terminal) is in contact with the negative electrode portion 20, the solid electrolyte layer 30, and the positive electrode margin portion 95a at the first side face S1 and the second side face S2.

[0055] According to the above configuration, compared to when the marginal portion is formed in a U-shape, the interface where the marginal portion contacts the positive electrode portion and the interface where the marginal portion contacts the negative electrode portion can be made smaller. This reduces the effect of thermal contraction mismatch during sintering. As a result, defects such as cracks and warpage can be eliminated.

[0056] In this embodiment, the positive electrode portion 10 extends from the first end face E1 to the second end face E2, and the negative electrode portion 20 extends from the first side face S1 to the second side face S2, but the positive electrode portion 10 may extend from the first side face S1 to the second side face S2, and the negative electrode portion 20 may extend from the first end face E1 to the second end face E2. In this case, the positive electrode margin portion 95a is exposed at the first end face E1 and the second end face E2, and the negative electrode margin portion 95b is exposed at the first side face S1 and the second side face S2.

[0057] If the all-solid-state battery 100a has a cubic shape, it may be difficult to identify the polarity of each external electrode. Therefore, it is preferable that the all-solid-state battery 100a has a substantially rectangular parallelepiped shape. For example, it is preferable that the length L and width W of the laminated chip 60 are different. In this case, it is possible to identify the polarity of each external electrode. For example, it is preferable that one of the length L and width W is 1.1 times or more the other. Alternatively, it is possible to identify the polarity of each external electrode by making the shapes of the external electrodes different. For example, if one external electrode is connected at the bottom surface F2 as in the all-solid-state battery 100a and the other external electrode is not connected at the bottom surface F2, it is possible to identify the polarity of each external electrode. If the polarity of each external electrode can be identified, there is no need to attach a new marker.

[0058] The thickness of the solid electrolyte layer 30 is, for example, 1 μm or more and 30 μm or less, 2 μm or more and 20 μm or less, or 3 μm or more and 15 μm or less.

[0059] The thicker the positive electrode portion 10 and the negative electrode portion 20 are formed, the more improved the battery capacity. For example, the thickness of the positive electrode portion 10 and the negative electrode portion 20 is preferably 1 μm or more, more preferably 5 μm or more, and even more preferably 10 μm or more. The thickness of the positive electrode portion 10 and the negative electrode portion 20 is preferably 0.03 times or more, more preferably 0.1 times or more, and even more preferably 0.3 times or more, the thickness of the solid electrolyte layer 30. Alternatively, the positive electrode portion 10 and the negative electrode portion 20 are preferably thicker than the solid electrolyte layer 30. The thicker the positive electrode portion 10 and the negative electrode portion 20 are formed, the larger the interfacial area between the marginal portion and the electrode portion when the marginal portion is formed in a U-shape, and therefore the effect of this embodiment can be said to be more pronounced.

[0060] On the other hand, if the positive electrode part 10 and the negative electrode part 20 are too thick, cracks may occur during heat treatment after the formation of the laminate. Even if no cracks occur, the battery may not respond sufficiently during operation. Therefore, it is preferable to set an upper limit on the thickness of the positive electrode part 10 and the negative electrode part 20. For example, the thickness of the positive electrode part 10 and the negative electrode part 20 is preferably 200 μm or less, more preferably 100 μm or less, and even more preferably 80 μm or less. Furthermore, the thickness of the positive electrode part 10 and the negative electrode part 20 is preferably 200 times or less, more preferably 100 times or less, and even more preferably 80 times or less, the thickness of the solid electrolyte layer 30.

[0061] The thickness of each solid electrolyte layer 30 in the Z-axis direction can be measured by observing a cross section of the all-solid-state battery 100a including the Z-axis direction with a scanning electron microscope (SEM), measuring the thickness at 10 points for each of 10 different solid electrolyte layers 30, and calculating the average value for all the measurement points. The thickness of each positive electrode portion 10 in the Z-axis direction can be measured by observing a cross section of the all-solid-state battery 100a including the Z-axis direction with an SEM, measuring the thickness at 10 points for each of 10 different positive electrode portions 10, and calculating the average value for all the measurement points. The thickness of each negative electrode portion 20 in the Z-axis direction can be measured by observing a cross section of the all-solid-state battery 100a including the Z-axis direction with an SEM, measuring the thickness at 10 points for each of 10 different negative electrode portions 20, and calculating the average value for all the measurement points.

[0062] Furthermore, if the composition of the positive electrode part 10 and the composition of the negative electrode part 20 are different, cracks are likely to occur due to the difference in thermal contraction behavior between the positive electrode part 10 and the negative electrode part 20, and therefore it can be said that the effect of this embodiment is significantly exhibited.

[0063] Next, a method for manufacturing the all-solid-state battery 100a will be described. Fig. 13 is a diagram illustrating a flow of the method for manufacturing the all-solid-state battery 100a.

[0064] (Electrolyte raw material powder production process) First, raw material powder for the solid electrolyte layer that constitutes the above-described solid electrolyte layer 30 is prepared. For example, raw materials, additives, etc. are mixed and a solid-phase synthesis method or the like is used to prepare raw material powder for an oxide-based solid electrolyte. The obtained raw material powder can be dry-pulverized to adjust the average particle size to a desired value. For example, the desired average particle size is adjusted using a planetary ball mill with 5 mm diameter ZrO2 balls.

[0065] (Cover raw powder production process) The ceramic raw material powder for the cover layer 50 is prepared. For example, raw materials, additives, etc. are mixed and the raw material powder for the cover layer can be prepared using a solid-phase synthesis method. The obtained raw material powder can be dry-milled to adjust the average particle size to the desired size. For example, the desired average particle size can be adjusted using a planetary ball mill with 5 mm diameter ZrO2 balls.

[0066] (raw powder production process for blank areas) The raw material powder for the negative electrode margin 95b and the positive electrode margin 95a is prepared. For example, raw materials, additives, etc. are mixed and solid-phase synthesis is used to prepare the raw material powder for the margin. The obtained raw material powder can be dry-milled to adjust the average particle size to the desired size. For example, the desired average particle size is adjusted using a planetary ball mill with 5 mm diameter ZrO2 balls.

[0067] (Electrode paste preparation process) Next, a positive electrode paste for producing the positive electrode part 10 and a negative electrode paste for producing the negative electrode part 20 are separately prepared. For example, the positive electrode paste and the negative electrode paste can be obtained by uniformly dispersing a conductive additive, an electrode active material, a solid electrolyte material, a sintering additive, a binder, a plasticizer, and the like in water or an organic solvent. The solid electrolyte paste described above may be used as the solid electrolyte material. A carbon material or the like may be used as the conductive additive. A metal may be used as the conductive additive. Examples of the metal conductive additive include Pd, Ni, Cu, Fe, and alloys containing these. Pd, Ni, Cu, Fe, alloys containing these, and various carbon materials may also be used.

[0068] The sintering aids contained in the paste for the positive electrode part and the paste for the negative electrode part include one or more glass components such as Li-BO-based compounds, Li-Si-O-based compounds, Li-CO-based compounds, Li-SO-based compounds, and Li-PO-based compounds.

[0069] (External electrode paste manufacturing process) Next, an external electrode paste is prepared for producing the above-described first external electrodes 41a, 41b and second external electrode 42. For example, the external electrode paste can be obtained by uniformly dispersing a conductive material, glass frit, a binder, a plasticizer, etc. in water or an organic solvent.

[0070] (Green sheet manufacturing process) The raw material powder for the solid electrolyte layer is uniformly dispersed in an aqueous or organic solvent along with a binder, dispersant, plasticizer, etc., and then wet-pulverized to obtain a solid electrolyte slurry with a desired average particle size. This process can be performed using a bead mill, wet jet mill, various kneaders, high-pressure homogenizers, etc., with the bead mill being preferred because it allows for simultaneous adjustment of particle size distribution and dispersion. A binder is added to the resulting solid electrolyte slurry to obtain a solid electrolyte paste. The resulting solid electrolyte paste can be coated to produce a solid electrolyte green sheet. The coating method is not particularly limited, and includes slot die coating, reverse coating, gravure coating, bar coating, doctor blade coating, etc. The particle size distribution after wet-pulverization can be measured, for example, using a laser diffraction measurement device employing a laser diffraction scattering method.

[0071] (Lamination and cutting process) As illustrated in FIG. 14, a positive electrode paste is printed on one surface of a first solid electrolyte green sheet 51a to form multiple band-shaped positive electrode pattern 52a. A positive electrode margin paste 53a is printed on the first solid electrolyte green sheet 51a in the gaps between the positive electrode pattern 52a. The positive electrode margin paste 53a can be formed by applying a raw material powder for the margin using a method similar to that used in the solid electrolyte green sheet preparation process. A negative electrode paste is printed on one surface of a second solid electrolyte green sheet 51b to form multiple band-shaped negative electrode pattern 52b. A negative electrode margin paste 53b is printed on the second solid electrolyte green sheet 51b in the gaps between the negative electrode pattern 52b.

[0072] 14, multiple first solid electrolyte green sheets 51a and multiple second solid electrolyte green sheets 51b are alternately stacked after printing so that the extending direction of the positive electrode part pattern 52a and the extending direction of the negative electrode part pattern 52b are perpendicular to each other. Cover sheets are pressed from above and below in the stacking direction to obtain a stacked body.

[0073] Next, as illustrated in FIG. 15, by cutting from the Z-axis direction along cut lines that run along the X-axis and Y-axis directions, a green chip of the laminated chip 60 before firing can be obtained.

[0074] (Firing process) Next, the resulting green chip is fired to obtain a laminated chip 60. Firing conditions include, but are not limited to, an oxidizing or non-oxidizing atmosphere, with a maximum temperature of preferably 400°C to 1000°C, more preferably 500°C to 900°C. A step of maintaining the temperature in an oxidizing atmosphere at a temperature lower than the maximum temperature may be provided to thoroughly remove the binder before the maximum temperature is reached. Firing at as low a temperature as possible is desirable to reduce process costs. After firing, a reoxidation treatment may be performed.

[0075] (External electrode formation process) Next, external electrode paste is applied to two end faces of the laminated chip 60 and then hardened to form the first external electrodes 41a, 41b and the second external electrode 42, thereby obtaining the all-solid-state battery 100a.

[0076] (Mounting and sealing process) Next, the all-solid-state battery 100a is mounted on a mounting substrate 200, and the all-solid-state battery 100a is sealed with an exterior member 301, thereby obtaining a package component 300. [Example]

[0077] (Example) A stacked-type all-solid-state battery was fabricated according to the above embodiment. As illustrated in FIG. 14, first solid electrolyte green sheets 51a printed with a positive electrode portion pattern 52a and a positive electrode margin paste 53a were alternately stacked, and second solid electrolyte green sheets 51b printed with a negative electrode portion pattern 52b and a negative electrode margin paste 53b were alternately stacked, with cover sheets provided above and below in the stacking direction. After pressure molding, the sheets were cut along the cut lines illustrated in FIG. 15 to obtain individual chips, which were then degreased and fired to obtain 24 stacked chips 60. No cracks or other defects were observed in any of the chips after firing.

[0078] As shown in FIG. 7, the first external electrodes 41a, 41b and the second external electrode 42 were formed to obtain an all-solid-state battery 100a, and a charge-discharge test was carried out, and no failure occurred in any of the chips during the first charge.

[0079] The all-solid-state battery 100a was mounted by soldering on the mounting substrate 200 illustrated in FIG. 8. Three solder joints were used. The mounting was possible without short-circuiting. The bonding strength was 200 N. Thereafter, as illustrated in FIG. 10, the all-solid-state battery 100a was sealed with an exterior member 301 to obtain a package component 300. By sealing, even in a state where the positive electrode portion and negative electrode portion were exposed from the side and end faces of the laminated chip, charge and discharge cycles could be repeated stably in the atmosphere.

[0080] (Comparative Example) As illustrated in FIG. 16 , a first solid electrolyte green sheet 51a printed with a positive electrode portion pattern 52a and a positive electrode margin paste 53a and a second solid electrolyte green sheet 51b printed with a negative electrode portion pattern 52b and a negative electrode margin paste 53b were alternately stacked, with cover sheets provided above and below the stacking direction. After pressure molding, the sheets were cut along the cut lines illustrated in FIG. 17 to obtain individual chips, which were then degreased and fired to obtain 24 laminated chips. As illustrated in FIG. 18 , the positive electrode margin paste 53a and the negative electrode margin paste 53b were formed into a U-shape. The size of the resulting laminated chip was the same as that of the laminated chip 60 of the example. Visually recognizable cracks were observed in three of the 24 chips.

[0081] It was difficult to visually distinguish the polarity of the laminated chips obtained in the comparative example. The polarity could be determined by observing them under a microscope, so they were mounted on a mounting board, paying attention to the orientation of the positive and negative electrodes. External electrodes were formed on 21 chips that had no cracks to obtain all-solid-state batteries, and charge / discharge tests were conducted. Soft short circuit failures were confirmed during the first charge in five chips. It was speculated that the problem during charging was caused by misalignment of the laminated structure due to internal microcracks growing due to volume changes in the electrodes during the charging process.

[0082] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to such specific embodiments, and various modifications and variations are possible within the scope of the gist of the present invention as defined in the claims. [Explanation of symbols]

[0083] 10 Positive electrode 20 negative electrode 30 Solid electrolyte layer 41a, 41b 1st external electrode 42 2nd external electrode 50 cover layers 51a First solid electrolyte green sheet 51b Second solid electrolyte green sheet 52a Positive electrode pattern 52b Negative electrode pattern 53a Positive electrode margin paste 53b Negative electrode margin paste 60 stacked chips 70 battery capacity area 81 First End Margin 82 Second End Margin 91 First side margin 92 Second Side Margin 95a Positive electrode margin 95b Negative electrode margin 100,100a all solid state battery

Claims

1. a laminate having a substantially rectangular parallelepiped shape, in which a first electrode layer including a first electrode portion and a first marginal portion and a second electrode layer including a second electrode portion different from the first electrode portion and a second marginal portion are laminated in plural with a solid electrolyte layer sandwiched therebetween; on four side surfaces other than the top surface and the bottom surface at the ends in the stacking direction of the laminate, the first marginal portions are arranged so as to be exposed to first two side surfaces facing each other, the first electrode portions are drawn out to second two side surfaces other than the first two side surfaces, the second marginal portions are arranged so as to be exposed to the second two side surfaces, and the second electrode portions are drawn out to the first two side surfaces.

2. two first external electrodes connected to the first two side surfaces, respectively; The all-solid-state battery according to claim 1 , further comprising: second external electrodes connected to the second two side surfaces.

3. 2. The all-solid-state battery according to claim 1, wherein a first length of the laminate in a direction in which the first two side surfaces face each other is different from a second length of the laminate in a direction in which the second two side surfaces face each other.

4. The all-solid-state battery according to claim 3 , wherein the first length is 1.1 times or more the second length.

5. 2. The all-solid-state battery according to claim 1, wherein the first electrode portion and the second electrode portion have a thickness of 1 μm or more and 200 μm or less.

6. 2. The all-solid-state battery according to claim 1, wherein the thickness of the first electrode portion and the second electrode portion is 0.03 times or more and 200 times or less the thickness of the solid electrolyte layer.

7. A substrate; The all-solid-state battery according to any one of claims 1 to 6 mounted on the substrate; and an exterior member that isolates the all-solid-state battery from outside air.

8. a first electrode layer including a first electrode portion pattern and a first marginal portion paste, and a second electrode layer including a second electrode portion pattern different from the first electrode portion pattern and a second marginal portion paste, the first electrode layer being stacked with a solid electrolyte layer green sheet sandwiched therebetween, the first marginal portion paste being arranged so as to be exposed to first two side surfaces opposing each other on four side surfaces other than a top surface and a bottom surface at an end in a stacking direction of the laminate, the first electrode portion pattern being extended to second two side surfaces other than the first two side surfaces, the second marginal portion paste being arranged so as to be exposed to the second two side surfaces, and the second electrode portion pattern being extended to the first two side surfaces.

9. The method for producing an all-solid-state battery according to claim 8 , wherein the surface of the laminate is polished before firing.

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