Secondary battery

Abstract

To provide a solid secondary battery with a high charging and discharging characteristic.SOLUTION: A first layer and a positive electrode active material layer are provided on a substrate. The first layer and the positive electrode active material layer are in contact with each other. The first layer is conductive. The first layer has a first crystal structure including a first cation and a first anion. The positive electrode active material layer has a second crystal structure including a second cation and a second anion. When the minimum value of the distance between the first cation and the first cation in the first crystal structure is La and the minimum value of the distance between the second cation and the second cation in the second crystal structure is Lb, the value of Expression (1) below is 0.1 or less.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] One embodiment of the present invention relates to an object, a method, or a manufacturing method. Alternatively, the present invention relates to a process, a machine, a manufacture, or a composition of matter. One embodiment of the present invention relates to a semiconductor device, a display device, a light-emitting device, a power storage device, a lighting device, an electronic device, or a manufacturing method thereof.

[0002] In this specification, the term "electronic device" refers to any device having a power storage device, and an electro-optical device having a power storage device, an information terminal device having a power storage device, and the like are all classified as electronic devices. [Background technology]

[0003] 2. Description of the Related Art Electronic devices that are carried by users or wearable electronic devices are being actively developed.

[0004] Primary or secondary batteries, which are examples of power storage devices, function as power sources for electronic devices carried by users or wearable electronic devices. It is desirable for electronic devices carried by users to be usable for long periods of time, and therefore large-capacity secondary batteries are used. However, large-capacity secondary batteries have the problem of being large and heavy. Therefore, development of small or thin large-capacity secondary batteries that can be built into portable electronic devices is underway.

[0005] The commonly used lithium ion secondary batteries use an electrolyte such as an organic solvent as a medium for moving the lithium ions, which are carrier ions. However, secondary batteries that use liquid have problems with electrolyte decomposition reactions and leakage due to the operating temperature range and operating potential. In addition, secondary batteries that use electrolyte have a risk of fire due to leakage.

[0006] As a secondary battery that does not use liquid, there is known an electricity storage device called a solid-state battery that uses a solid electrolyte. For example, Patent Document 1 discloses such a device. Patent Document 2 discloses a solid-state secondary battery that uses a graft polymer. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] U.S. Patent No. 8,404,001 [Patent Document 2] JP 2011-014387 A Summary of the Invention [Problem to be solved by the invention]

[0008] Thin-film solid-state secondary batteries (also called thin-film all-solid-state batteries) have room for improvement in various aspects, such as charge / discharge characteristics, cycle characteristics, reliability, safety, and cost. For example, in order to increase the charge / discharge capacity of a thin-film all-solid-state battery, a method of increasing the crystallinity of the positive electrode active material layer can be mentioned. In order to increase the crystallinity, a method of heat treatment at high temperature can be mentioned, but the heat treatment may be difficult depending on the material of the positive electrode current collector or substrate.

[0009] In view of the above, an object of one embodiment of the present invention is to provide a solid-state secondary battery having a large charge / discharge capacity. Alternatively, an object of one embodiment of the present invention is to provide a solid-state secondary battery having favorable cycle characteristics. Alternatively, an object of one embodiment of the present invention is to provide a novel all-solid-state secondary battery that is safer than a conventional lithium-ion secondary battery that uses an electrolyte solution. Alternatively, an object of one embodiment of the present invention is to provide a novel power storage device.

[0010] Note that the description of these problems does not preclude the existence of other problems. Note that one embodiment of the present invention does not necessarily solve all of these problems. Note that it is possible to extract problems other than these from the description of the specification, drawings, and claims. [Means for solving the problem]

[0011] One embodiment of the present invention is a solid secondary battery having a first layer and a positive electrode active material layer on a substrate, the first layer and the positive electrode active material layer being in contact with each other, the first layer being conductive, the first layer having a first crystal structure having a first cation and a first anion, the positive electrode active material layer having a second crystal structure having a second cation and a second anion, wherein the value of the following formula (1) is 0.1 or less, where La is the minimum distance between the first cation and the first cation in the first crystal structure, and Lb is the minimum distance between the second cation and the second cation in the second crystal structure.

[0012]

number

[0013] One embodiment of the present invention is a solid-state secondary battery that includes a first layer and a positive electrode active material layer over a substrate, the first layer and the positive electrode active material layer being in contact with each other, the first layer being conductive, the first layer having a first crystal structure having a first cation and a first anion, and the positive electrode active material layer having a second crystal structure having a second cation and a second anion, wherein a value of the following formula (2) is 0.1 or less, where la is a minimum distance between the first cation and the first cation in the first crystal structure, and lb is a minimum distance between the second cation and the second cation in the second crystal structure.

[0014]

number

[0015] In the above-mentioned structure, the second cation preferably has a transition metal.

[0016] In the above configuration, it is preferable that the minimum angle between the first cations and the first anions is 85° or more and 90° or less, and the minimum angle between the second cations and the second anions is 85° or more and 90° or less.

[0017] In the above structure, it is preferable that the first crystal structure is a rock salt type and the second crystal structure is a layered rock salt type.

[0018] In the above configuration, it is preferable that the substrate and the first layer have the same metal.

[0019] In the above-mentioned configuration, it is preferable that a positive electrode current collector layer is provided between the substrate and the first layer, and it is more preferable that the positive electrode current collector layer and the first layer have the same metal.

[0020] In the above structure, the positive electrode active material layer preferably contains lithium cobalt oxide.

[0021] In the above structure, the first layer preferably contains titanium nitride. Effect of the Invention

[0022] According to one embodiment of the present invention, a solid-state secondary battery having a large charge / discharge capacity can be provided. Alternatively, according to one embodiment of the present invention, a solid-state secondary battery having favorable cycle characteristics can be provided. Alternatively, according to one embodiment of the present invention, a novel all-solid-state secondary battery having higher safety than a conventional lithium-ion secondary battery using an electrolyte solution can be provided. Alternatively, according to one embodiment of the present invention, a novel power storage device can be provided.

[0023] Furthermore, the capacity of a thin-film solid secondary battery can also be increased by increasing its area.

[0024] In addition, by using the peel-and-transpose technique, it is possible to enlarge the area and then fold it to a desired size. [Brief description of the drawings]

[0025] [Figure 1] 1A and 1B are cross-sectional views showing one embodiment of the present invention. [Diagram 2] FIG. 2A is a diagram illustrating the crystal structure of titanium nitride, and FIG. 2B is a diagram illustrating the crystal structure of LiCoO2. [Diagram 3] 3A, 3B, and 3C are cross-sectional views showing one embodiment of the present invention. [Figure 4] 4A and 4B are a top view and a cross-sectional view illustrating one embodiment of the present invention. [Diagram 5] FIG. 5 is a diagram illustrating a production flow of a solid secondary battery according to one embodiment of the present invention. [Figure 6] 6A and 6B are top views showing one embodiment of the present invention. [Figure 7] FIG. 7 is a cross-sectional view showing one embodiment of the present invention. [Figure 8] FIG. 8 is a diagram illustrating a production flow of a solid secondary battery according to one embodiment of the present invention. [Figure 9] FIG. 9 is a schematic top view of a manufacturing apparatus for a solid secondary battery. [Figure 10] FIG. 10 is a cross-sectional view of a part of an apparatus for manufacturing a solid secondary battery. [Figure 11] FIG. 11A is a perspective view showing an example of a battery cell, FIG. 11B is a perspective view of a circuit, and FIG. 11C is a perspective view of the battery cell and the circuit superimposed on each other. [Figure 12] FIG. 12A is a perspective view showing an example of a battery cell, FIG. 12B is a perspective view of a circuit, and FIGS. 12C and 12D are perspective views of the battery cell and the circuit superimposed on each other. [Figure 13] FIG. 13A is a perspective view of a battery cell, and FIG. 13B is a diagram showing an example of an electronic device. [Figure 14] 14A, 14B, and 14C are diagrams showing an example of an electronic device. [Figure 15] FIG. 15A is a schematic diagram of a device showing one embodiment of the present invention, FIG. 15B is a diagram showing a part of the system, and FIG. 15C is an example of a perspective view of a portable data terminal used in the system. [Figure 16] FIG. 16 is a diagram illustrating the XRD measurement results of each sample according to the example. [Figure 17] 17A and 17B are diagrams illustrating the charge and discharge characteristics of a solid secondary battery according to an example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] Hereinafter, the embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the following description, and it will be easily understood by those skilled in the art that the form and details of the present invention can be modified in various ways. Furthermore, the present invention is not to be interpreted as being limited to the description of the embodiments shown below.

[0027] In addition, in this specification and the like, crystal planes and directions are represented using Miller indices. Individual planes indicating crystal planes are represented in parentheses.

[0028] (Embodiment 1) A solid secondary battery of one embodiment of the present invention will be described with reference to FIGS. 1A, 1B, 2A, and 2B.

[0029] <Configuration example 1 of solid secondary battery> 1A and 1B includes at least a positive electrode current collector layer 201, an undercoat film 210, a positive electrode active material layer 202, a solid electrolyte layer 203, a negative electrode active material layer 204, and a negative electrode current collector layer 205 on a substrate 101, in this order.

[0030] Since the crystallinity of the positive electrode active material layer affects the charge / discharge characteristics of a solid secondary battery, it is preferable that the crystallinity of the positive electrode active material layer is high. In a solid secondary battery having a positive electrode (having at least a positive electrode current collector layer and a positive electrode active material layer) on the substrate side, if a material having a metal atomic distance significantly different from the distance between transition metal atoms in the positive electrode active material layer is used for the positive electrode current collector layer and a solid secondary battery is manufactured in a structure in which the positive electrode current collector layer and the positive electrode active material layer are in contact with each other, the crystallinity of the positive electrode active material layer may be low, and the capacity of the solid secondary battery may not be sufficient.

[0031] Here, the inventors have found that by using a material having a metal atomic distance similar to the distance between transition metal atoms in the positive electrode active material layer as the undercoat film, it is possible to increase the crystallinity of the positive electrode active material layer and improve the charge / discharge characteristics of the solid secondary battery.

[0032] In the solid-state secondary battery of one embodiment of the present invention, a base film 210 is introduced between the positive electrode current collector layer 201 and the positive electrode active material layer 202 so as to be in contact with the positive electrode active material layer 202, and a material having a metal atomic distance similar to the distance between transition metal atoms in the positive electrode active material layer 202 is used for the base film 210. By forming the positive electrode active material layer 202 on the base film 210, it is possible to form the positive electrode active material layer 202 with approximately the same crystal orientation. Therefore, the crystallinity of the positive electrode active material layer 202 can be increased, and a solid-state secondary battery with favorable charge / discharge characteristics can be formed.

[0033] Here, it is preferable that the base film 210 has electrical conductivity. By having electrical conductivity, the crystallinity of the positive electrode active material layer 202 can be increased without deteriorating the characteristics of the secondary battery.

[0034] When the positive electrode active material layer 202 is fabricated so that its crystal orientation roughly coincides with that of the undercoat film 210, the positive electrode active material layer 202 has a crystal orientation that roughly coincides in three dimensions with that of the undercoat film 210. In other words, the undercoat film 210 and the positive electrode active material layer 202 are topotaxy. To achieve topotaxy, the distance between the metal atoms of the material used in the undercoat film 210 and the distance between the transition metal atoms of the material used in the positive electrode active material layer 202 are important.

[0035] Here, consider a case where conductive ionic crystal A is used for base film 210, and ionic crystal B is used for positive electrode active material layer 202. In order to form ionic crystal B on ionic crystal A with roughly identical crystal orientation, it is preferable that ionic crystal A and ionic crystal B have similar crystal structures. Specifically, when the minimum cation (metal atom)-cation (metal atom) distance in ionic crystal A is La, and the minimum cation (transition metal atom)-cation (transition metal atom) distance in ionic crystal B is Lb, the value represented by the following formula (1) is preferably 0.1 or less, and more preferably 0.06 or less.

[0036]

number

[0037] The above La may be the distance between the same cations or different cations, but is the minimum distance between cations in the ideal crystal structure of ionic crystal A. Similarly, the above Lb may be the distance between the same cations or different cations, but is the minimum distance between cations (transition metals) in the ideal crystal structure of ionic crystal B.

[0038] As described above, it is preferable to use a material that is conductive and has a value represented by formula (1) of 0.1 or less, and more preferably 0.06 or less, for the base film 210. When lithium cobalt oxide is used for the positive electrode active material layer 202, it is possible to suitably use, for example, titanium nitride (TiN), aluminum (Al), aluminum nitride (AlN), aluminum oxide (Al2O3), LiNbO3, tantalum nitride (TaN), titanium oxide, Cu, or the like for the base film 210.

[0039] Furthermore, in order to roughly align the crystal orientation, attention is focused on La and Lb in formula (1) as described above, but attention may also be focused on the distance between the cation and anion in the ionic crystal.

[0040] When a conductive ionic crystal A is used for the base film 210 and an ionic crystal B is used for the positive electrode active material layer 202, when the minimum anion (non-metallic atom)-anion (non-metallic atom) distance in the ionic crystal A is la and the minimum anion (non-metallic atom)-anion (non-metallic atom) distance in the ionic crystal B is lb, the value represented by the following formula (2) is preferably 0.1 or less, and more preferably 0.07 or less.

[0041]

number

[0042] For the undercoat film 210, a material having conductivity and having a value represented by formula (2) of 0.1 or less is preferably used, and a material having a value of 0.07 or less is more preferably used. When lithium cobalt oxide is used for the positive electrode active material layer 202, for example, titanium nitride (TiN), aluminum (Al), aluminum nitride (AlN), aluminum oxide (Al2O3), LiNbO3, tantalum nitride (TaN), titanium oxide, Cu, etc. can be suitably used for the undercoat film 210.

[0043] Here, the relationship between the above formulas (1) and (2) will be explained by taking as an example a case where titanium nitride (TiN) is used for the undercoat film 210 and lithium cobalt oxide (LiCoO2) is used for the positive electrode active material layer 202. FIG. 2A and FIG. 2B show (111) of titanium nitride (rock salt type) and (003) of lithium cobalt oxide. From FIG. 2A and FIG. 2B, the minimum distance between titanium atoms of titanium nitride (La in formula (1)) is 0.2997 nm, and the distance between cobalt atoms of lithium cobalt oxide (Lb in formula (1)) is 0.2816 nm, and the value obtained by formula (1) is approximately 0.06. Therefore, titanium nitride can be suitably used as an undercoat film.

[0044] 2A and 2B, the minimum distance between nitrogen atoms in titanium nitride (la in formula (2)) is 0.2997 nm, and the minimum distance between oxygen atoms in lithium cobalt oxide (lb in formula (2)) is 0.2816 nm, and the value calculated by formula (2) is approximately 0.06. Therefore, titanium nitride can be suitably used as an undercoat film.

[0045] The above interatomic (ionic) distances can be calculated by XRD measurement, electron beam diffraction measurement, neutron beam diffraction measurement, or the like.

[0046] In addition, when the crystal orientation is roughly matched during film formation, it is preferable that the undercoat film 210 and the positive electrode active material layer 202 have similar crystal structures. Therefore, it is preferable to use a material in which the minimum angle between the transition metal atom of the positive electrode active material layer 202 and the nonmetallic atom coordinated to the transition metal atom is 85° or more and 90° or less, the minimum angle between the metal atom of the undercoat film 210 and the nonmetallic atom coordinated to the metal atom is 85° or more and 90° or less, and further, at least one of the values ​​of the above formulas (1) and (2) is 0.1 or less (more preferably 0.07 or less). By using a material with such a configuration, it is possible to obtain a positive electrode active material layer 202 having high crystallinity.

[0047] In the case of the above-mentioned lithium cobalt oxide, if a crystal structure model is assumed in which a cobalt atom, which is a transition metal, is coordinated with six oxygen atoms, the angles between the cobalt atom and the oxygen atom are considered to be 180° and 90°. Therefore, in the case of lithium cobalt oxide, the minimum angle between the cobalt atom and the oxygen atom coordinated with the cobalt atom is 90°. Similarly, in the case of titanium nitride, if a crystal structure model is assumed in which titanium, which is a metal atom, is coordinated with six nitrogen atoms, the angles between the titanium atom and the nitrogen atom are considered to be 180° and 90°. Therefore, in the case of titanium nitride, the minimum angle between the titanium atom and the nitrogen atom coordinated with the titanium atom is 90°.

[0048] In addition, when the films are formed with the crystal orientations roughly aligned, it is preferable that the undercoat film 210 and the positive electrode active material layer 202 have similar crystal structures. Therefore, it is preferable to use a layered rock salt type material for the positive electrode active material layer 202, and a material having a rock salt type crystal structure for the undercoat film 210, in which at least one of the values ​​of the above formulas (1) and (2) is 0.1 or less (more preferably 0.07 or less). By using materials with this configuration, it is possible to obtain a positive electrode active material layer 202 with high crystallinity. The above-mentioned lithium cobalt oxide is a material having a layered rock salt type crystal structure, and titanium nitride is a material having a rock salt type crystal structure.

[0049] <Configuration Example 2 of Solid Secondary Battery> 1B shows a solid-state secondary battery 152 different from the solid-state secondary battery 150 shown in Fig. 1A. The solid-state secondary battery 152 shown in Fig. 1B has at least a negative electrode current collector layer 205, a negative electrode active material layer 204, a solid electrolyte layer 203, a base film 210, a positive electrode active material layer 202, and a positive electrode current collector layer 201, in this order, on a substrate 101. It can be said that the solid-state secondary battery 150 is a solid-state secondary battery having a positive electrode on the substrate 101 side, and the solid-state secondary battery 152 is a solid-state secondary battery having a negative electrode (having at least a negative electrode current collector layer and a negative electrode active material layer) on the substrate 101 side.

[0050] In order to improve the crystallinity of the positive electrode active material layer 202, it is necessary to prepare the positive electrode active material layer 202 in contact with the undercoat film 210. Therefore, in the solid secondary battery 152, the undercoat film 210 is formed on the solid electrolyte layer 203, and then the positive electrode active material layer 202 is formed. That is, the undercoat film 210 is formed between the solid electrolyte layer 203 and the positive electrode active material layer 202. With this configuration, and further using ionic crystal A and ionic crystal B, in which at least one of the values ​​of the above formulas (1) and (2) is 0.1 or less, for the undercoat film 210 and the positive electrode active material layer 202, respectively, a solid secondary battery with good charge / discharge efficiency can be obtained.

[0051] <Configuration Example 3 of Solid Secondary Battery> Solid-state secondary batteries different from the solid-state secondary battery 150 and the solid-state secondary battery 152 shown in FIGS. 1A and 1B are shown in FIGS. 3A, 3B, and 3C.

[0052] The solid secondary battery 154 shown in FIG. 3A has at least a positive electrode current collector layer 212, a positive electrode active material layer 202, a solid electrolyte layer 203, a negative electrode active material layer 204, and a negative electrode current collector layer 205 on a substrate 101 in this order.

[0053] The solid-state secondary battery 154 is characterized in that ionic crystal A and ionic crystal B, in which at least one of the values ​​of the above-mentioned formula (1) and formula (2) is 0.1 or less, are used for the positive electrode current collector layer 212 and the positive electrode active material layer 202, respectively. By adopting this configuration, it is possible to prepare a positive electrode active material layer 202 with high crystallinity without using an undercoat film. Therefore, it is possible to easily prepare a solid-state secondary battery with good characteristics.

[0054] The solid secondary battery 156 shown in FIG. 3B has at least a positive electrode current collector layer 214, a base film 210, a positive electrode active material layer 202, a solid electrolyte layer 203, a negative electrode active material layer 204, and a negative electrode current collector layer 205 stacked in this order.

[0055] The solid secondary battery 156 is characterized in that ionic crystal A and ionic crystal B, in which at least one of the values ​​of the above formula (1) and formula (2) is 0.1 or less, are used for the undercoat film 210 and the positive electrode active material layer 202, respectively. In addition, the positive electrode current collector layer 214 has a function as a positive electrode current collector and a function as a substrate. With this configuration, the positive electrode current collector layer 214 can serve both as a substrate and a positive electrode current collector layer, and a positive electrode active material layer 202 with high crystallinity can be produced. Therefore, a solid secondary battery with good characteristics can be produced easily.

[0056] The solid secondary battery 158 shown in FIG. 3C includes at least a positive electrode current collector layer 216, a positive electrode active material layer 202, a solid electrolyte layer 203, a negative electrode active material layer 204, and a negative electrode current collector layer 205, in this order.

[0057] The solid secondary battery 158 is characterized in that ionic crystal A and ionic crystal B, in which at least one of the values ​​of the above formula (1) and formula (2) is 0.1 or less, are used in the positive electrode collector layer 216 and the positive electrode active material layer 202, respectively. Furthermore, the positive electrode collector layer 216 functions as a positive electrode collector and as a substrate. With this configuration, a positive electrode active material layer with high crystallinity can be produced without using an undercoat film. Therefore, a solid secondary battery with good characteristics can be produced easily.

[0058] 1A and 1B have an advantage of having a wide range of options for the positive electrode current collector material since there is no particular limitation on the material used for the positive electrode current collector layer 201. The solid secondary battery 154, the solid secondary battery 156, and the solid secondary battery 158 have an advantage of being easy to fabricate.

[0059] <Configuration Example 4 of Solid Secondary Battery> 4A and 4B show a solid-state secondary battery according to one embodiment of the present invention, in which Fig. 4A is a top view and Fig. 4B is a cross-sectional view taken along line AA' in Fig. 4A.

[0060] As shown in Fig. 4B, a positive electrode current collector layer 201 is formed on a substrate 101, and an undercoat film 210, a positive electrode active material layer 202, a solid electrolyte layer 203, a negative electrode active material layer 204, a negative electrode current collector layer 205, and a protective layer 206 are laminated in this order on the positive electrode current collector layer 201. The single-layer cell 200 has at least the positive electrode current collector layer 201, the positive electrode active material layer 202, the solid electrolyte layer 203, the negative electrode active material layer 204, and the negative electrode current collector layer 205. Fig. 4B shows a case where an undercoat film 210 is further provided.

[0061] These films can be formed using a metal mask. The positive electrode collector layer 201, the base film 210, the positive electrode active material layer 202, the solid electrolyte layer 203, the negative electrode active material layer 204, the negative electrode collector layer 205, and the protective layer 206 may be selectively formed using a sputtering method. Alternatively, the solid electrolyte layer 203 may be selectively formed using a metal mask by co-evaporation.

[0062] 4A, a part of the negative electrode current collector layer 205 is exposed to form a negative electrode terminal portion. The area of ​​the negative electrode current collector layer 205 other than the negative electrode terminal portion is covered with a protective layer 206. In addition, a part of the positive electrode current collector layer 201 is exposed to form a positive electrode terminal portion. The area of ​​the positive electrode current collector layer 201 other than the positive electrode terminal portion is covered with a protective layer 206.

[0063] The protective layer 206 can be made of a metal oxide containing one or more elements selected from hafnium, aluminum, gallium, yttrium, zirconium, tungsten, titanium, tantalum, nickel, germanium, neodymium, lanthanum, magnesium, etc. Silicon nitride oxide or silicon nitride can also be used. The protective layer 206 can be formed by sputtering.

[0064] As a single-layer cell, a configuration in which the solid-state secondary batteries 150, 152, 154, 156, and 158 are stacked in this order can also be used.

[0065] (Embodiment 2) This embodiment describes a method for manufacturing the solid secondary battery described in Embodiment 1. FIG. 5 shows an example of a manufacturing flow for obtaining the structure shown in FIG. 4A and FIG. 4B.

[0066] First, the positive electrode collector layer 201 is formed on a substrate. As a film formation method, a sputtering method, a vapor deposition method, or the like can be used. A conductive substrate may be used as the collector. As the positive electrode collector layer 201, a material having high conductivity, such as a metal such as stainless steel, gold, platinum, aluminum, titanium, or an alloy thereof, can be used. In addition, it is preferable that the material used for the positive electrode collector layer 201 does not dissolve at the potential of the positive electrode. In addition, an aluminum alloy to which an element that improves heat resistance, such as silicon, titanium, neodymium, scandium, or molybdenum, is added can be used. In addition, the positive electrode collector layer 201 may be formed of a metal element that reacts with silicon to form a silicide. Examples of the metal element that reacts with silicon to form a silicide include zirconium, titanium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, cobalt, and nickel. The collector may be appropriately shaped in a foil, plate (sheet), net, punched metal, or expanded metal form. The thickness of the positive electrode current collector layer 201 is preferably 5 μm or more and 30 μm or less. The positive electrode current collector layers 212, 214, and 216 may also be made of the above-mentioned materials.

[0067] The substrate 101 may be a ceramic substrate, a glass substrate, a plastic substrate, a silicon substrate, a metal substrate, or the like.

[0068] Next, the base film 210 is formed. The base film 210 can be formed by sputtering, vapor deposition, or the like. In the sputtering method, the base film 210 can be selectively formed by using a metal mask. The base film 210 may be patterned by selectively removing the base film 210 by dry etching or wet etching using a resist mask or the like.

[0069] The undercoat film 210 preferably has high crystallinity. To obtain a highly crystalline undercoat film 210, a certain degree of thickness is necessary. Therefore, the thickness of the undercoat film 210 is preferably 20 nm or more, more preferably 100 nm or more, and even more preferably 200 nm or more. Moreover, the thickness of the undercoat film 210 is preferably 1 μm or less, and more preferably 500 nm or less.

[0070] In addition, the material used for the undercoat film 210 is preferably a material having the same metal as the metal contained in the positive electrode collector layer 201. For example, it is preferable to use titanium as the positive electrode collector layer 201 and titanium nitride as the undercoat film 210. In this configuration, the positive electrode collector layer 201 and the undercoat film 210 can be manufactured using the same target. That is, the positive electrode collector layer 201 is manufactured by a sputtering method using a titanium target, and the undercoat film 210 can be manufactured using the titanium target by utilizing a reactive sputtering method. By manufacturing the positive electrode collector layer 201 and the undercoat film 210 using the same target, a solid secondary battery can be manufactured easily, leading to cost reduction.

[0071] Next, the positive electrode active material layer 202 is formed on the undercoat film 210. The positive electrode active material layer 202 can be formed by a sputtering method using a sputtering target mainly composed of lithium cobalt oxide (LiCoO2, LiCo2O4, etc.), a sputtering target mainly composed of lithium manganese oxide (LiMnO2, LiMn2O4, etc.), or a lithium nickel oxide (Li with O2, LiNi2O4, etc.). In addition, lithium manganese cobalt oxide (LiMnCoO4, Li2MnCoO4, etc.), nickel cobalt manganese ternary material (LiNi1 / 3 Mn 1 / 3 Co 1 / 3 O2:NCM), nickel-cobalt-aluminum ternary material (LiNi 0.8 Co 0.15 Al 0.05 O2:NCA) or the like can also be used. Alternatively, the film may be formed by a vacuum evaporation method. Note that in the solid-state secondary battery of one embodiment of the present invention, the positive electrode active material layer 202 is heteroepitaxially grown during film growth (film formation).

[0072] As described above, by combining the materials of the undercoat film 210 and the positive electrode active material layer 202 such that at least one of the values ​​of formula (1) and formula (2) is 0.1 or less, a positive electrode active material layer 202 with good crystallinity can be manufactured.

[0073] Moreover, it is preferable to form the positive electrode active material layer 202 at a high temperature (500° C. or higher). Alternatively, it is preferable to perform an annealing treatment (500° C. or higher) after forming the positive electrode active material layer 202. By using such a forming method, it is possible to form the positive electrode active material layer 202 with better crystallinity.

[0074] In addition, in a positive electrode using a metal for the positive electrode collector layer 201, the above-mentioned annealing treatment may cause the metal of the positive electrode collector layer 201 to diffuse into the positive electrode active material layer 202, and the charge / discharge characteristics may deteriorate. That is, the characteristics may deteriorate due to the annealing treatment. On the other hand, in the positive electrode of the solid secondary battery of one embodiment of the present invention, the base film 210 is provided between the positive electrode collector layer 201 and the positive electrode active material layer 202. Therefore, the diffusion of the metal of the positive electrode collector layer 201 into the positive electrode active material layer 202 can be suppressed. That is, the base film 210 acts as a diffusion prevention film. Therefore, in the solid secondary battery of one embodiment of the present invention, the crystallinity of the positive electrode active material layer 202 can be increased by the annealing treatment without deteriorating the charge / discharge characteristics.

[0075] Next, the solid electrolyte layer 203 is formed. The material for the solid electrolyte layer is Li3PO 4、 LixPO (4-y) Ny, Li 0.35 La 0.55TiO3, La (2 / 3-x) Li 3x TiO 3、 LiNb (1-x) Ta (x) WO6, Li7La3Zr2O 12 , Li (1+x) Al (x) Ti (2-x) (PO4)3, Li (1+x) Al (x) Ge (2-x) (PO4)3, LiNbO2, etc. can be mentioned. Note that X > 0, Y >. As the film formation method, sputtering method, evaporation method, etc. can be used. Also, SiO X (0 < X ≤ 2) can also be used as the solid electrolyte layer 203. SiO X (0 < X ≤ 2) is used as the solid electrolyte layer 203, and further, SiO X (0 < X ≤ 2) can be used as the negative electrode active material layer 204. In this case, the ratio of silicon to oxygen (O / Si) of SiO X is preferably higher in the solid electrolyte layer 203. By adopting such a configuration, conductive ions (especially lithium ions) diffuse easily in the solid electrolyte layer 203, and conductive ions (especially lithium ions) are easily desorbed or accumulated in the negative electrode active material layer 204, so that a solid secondary battery with good characteristics can be obtained. By using materials composed of the same components for the solid electrolyte layer 203 and the negative electrode material layer 204 as described above, a solid secondary battery can be easily manufactured.

[0076] Also, the solid electrolyte layer 203 may have a laminated structure. When laminating, a material obtained by adding nitrogen to lithium phosphate (Li3PO4) (also called Li3PO( 4-Z) N Z :LiPON) may be laminated. Note that Z > 0.

[0077] Next, the negative electrode active material layer 204 is formed. For the negative electrode active material layer 204, a film mainly composed of silicon, a film mainly composed of carbon, a titanium oxide film, a vanadium oxide film, an indium oxide film, a zinc oxide film, a tin oxide film, a nickel oxide film, or the like can be used by using a sputtering method or the like. Films that are alloyed with Li, such as tin, gallium, or aluminum, can be used. Metal oxide films that are alloyed with these may also be used. A Li metal film may also be used as the negative electrode active material layer 204. Lithium titanium oxide (Li4Ti5O 12 , LiTi2O4, etc.) may be used, but among them, a film containing silicon and oxygen is preferable.

[0078] Next, the negative electrode current collector layer 205 is fabricated. As the material of the negative electrode current collector layer 205, one or more conductive materials selected from Al, Ti, Cu, Au, Cr, W, Mo, Ni, Ag, etc. are used. As the film formation method, a sputtering method, a vapor deposition method, etc. can be used. In addition, in the sputtering method, a film can be selectively formed by using a metal mask. Also, the conductive film may be patterned by selectively removing the conductive film by dry etching or wet etching using a resist mask, etc.

[0079] In addition, when the positive electrode current collector layer 201 and the negative electrode current collector layer 205 are formed by a sputtering method, it is preferable to form at least one of the positive electrode active material layer 202 and the negative electrode active material layer 204 by a sputtering method. The sputtering device can perform continuous film formation in the same chamber or using multiple chambers, and can also be a multi-chamber type manufacturing device or an in-line type manufacturing device. The sputtering method is a manufacturing method suitable for mass production using a chamber and a sputtering target. In addition, the sputtering method can be formed thinly and has excellent film formation characteristics.

[0080] Furthermore, the layers described in this embodiment are not limited to being formed by sputtering, and gas phase methods (vacuum deposition, thermal spraying, pulsed laser deposition (PLD), ion plating, cold spray, aerosol deposition) can also be used. The aerosol deposition (AD) method is a method for forming a film without heating the substrate. Aerosol refers to fine particles dispersed in a gas. Alternatively, a CVD method or an ALD (Atomic Layer Deposition) method can be used.

[0081] (Embodiment 3) In order to increase the output voltage of the solid secondary battery, the solid secondary batteries can be connected in series. In the first embodiment, an example of a single-layer cell is shown, but in the present embodiment, an example of manufacturing a solid secondary battery connected in series is shown.

[0082] Fig. 6A shows a top view of the first solid secondary battery immediately after its formation, and Fig. 6B shows a top view of two solid secondary batteries connected in series. In Fig. 6A and Fig. 6B, the same reference numerals are used for the same parts as Fig. 4A and Fig. 4B shown in the first embodiment.

[0083] Fig. 6A shows the state immediately after the deposition of the negative electrode current collector layer 205. The shape of the top surface of the negative electrode current collector layer 205 is different from that of Fig. 4A. The negative electrode current collector layer 205 shown in Fig. 6A is in contact with a part of the side surface of the solid electrolyte layer and also in contact with the insulating surface of the substrate. This insulating surface is also in contact with the first negative electrode.

[0084] 4B, a second negative electrode active material layer is formed on a region of the negative electrode current collector layer 205 that does not overlap with the first negative electrode active material layer. Then, a second solid electrolyte layer 211 is formed, and a second base film, a second positive electrode active material layer, and a second positive electrode current collector 213 are formed thereon. Finally, a protective layer 206 is formed.

[0085] FIG. 6B shows a configuration in which two solid-state secondary batteries are arranged on a plane and connected in series.

[0086] (Embodiment 4) An example of a single-layer cell is shown in the first embodiment, but an example of a multi-layer cell is shown in the present embodiment. Fig. 7 shows one embodiment of a multi-layer cell of a thin-film solid secondary battery.

[0087] FIG. 7 shows an example of a cross section of a three-layer cell.

[0088] A positive electrode current collector layer 201 is formed on a substrate 101, and a base film 210, a positive electrode active material layer 202, a solid electrolyte layer 203, a negative electrode active material layer 204, and a negative electrode current collector layer 205 are sequentially formed on the positive electrode current collector layer 201 to constitute a first cell.

[0089] Furthermore, a second negative electrode active material layer, a second solid electrolyte layer, a second base film, a second positive electrode active material layer, and a second positive electrode current collector layer are sequentially formed on the negative electrode current collector layer 205 to form a second cell.

[0090] Furthermore, a third undercoat film, a third positive electrode active material layer, a third solid electrolyte layer, a third negative electrode active material layer, and a third negative electrode current collector layer are sequentially formed on the second positive electrode current collector to form a third cell.

[0091] Here, in the solid secondary battery of one embodiment of the present invention, the crystallinity of the positive electrode active material layer can be improved by introducing an undercoat film into a layer that is in contact with the positive electrode active material layer and is on the substrate side. There is no particular limit to the location where the undercoat film can be formed, so it can be formed on the positive electrode current collector layer or on the solid electrolyte layer as shown in Figure 7. Therefore, the present invention can be suitably used in a solid secondary battery of a multi-layer cell.

[0092] In Fig. 7, a protective layer 206 is formed last. The three-layer laminate shown in Fig. 7 is configured to be connected in series to increase capacity, but it can also be connected in parallel with external wiring. Also, series and parallel or series-parallel can be selected with external wiring.

[0093] It is preferable to use the same material for solid electrolyte layer 203, the second solid electrolyte layer, and the third solid electrolyte layer, since this reduces manufacturing costs.

[0094] FIG. 8 shows an example of a manufacturing flow for obtaining the structure shown in FIG.

[0095] In Fig. 8, in order to reduce the number of manufacturing steps, it is preferable to use an LCO film (lithium cobalt oxide film (LiCoO2)) as the positive electrode active material layer and a titanium film as the positive and negative electrode current collectors (conductive layers). By using a titanium film as a common electrode, a three-layer stacked cell is realized with a small configuration.

[0096] This embodiment mode can be appropriately combined with other embodiment modes.

[0097] (Embodiment 5) In this embodiment, an example of a multi-chamber manufacturing apparatus capable of fully automating the manufacturing process from the positive electrode current collector layer to the negative electrode current collector layer of a secondary battery is shown in Fig. 9 and Fig. 10. The manufacturing apparatus can be suitably used for manufacturing the solid secondary battery of one embodiment of the present invention.

[0098] Figure 9 shows an example of a multi-chamber manufacturing apparatus equipped with gates 880, 881, 882, 883, 884, 885, 886, 887, 888, a load lock chamber 870, a mask alignment chamber 891, a first transfer chamber 871, a second transfer chamber 872, a third transfer chamber 873, multiple film formation chambers (first film formation chamber 892, second film formation chamber 874), a heating chamber 893, a second material supply chamber 894, a first material supply chamber 895, and a third material supply chamber 896.

[0099] The mask alignment chamber 891 includes at least a stage 851 and a substrate transport mechanism 852 .

[0100] The first transfer chamber 871 has a substrate cassette lifting mechanism, the second transfer chamber 872 has a substrate transfer mechanism 853 , and the third transfer chamber has a substrate transfer mechanism 854 .

[0101] The first film formation chamber 892, the second film formation chamber 874, the second material supply chamber 894, the first material supply chamber 895, the third material supply chamber 896, the mask alignment chamber 891, the first transfer chamber 871, the second transfer chamber 872, and the third transfer chamber 873 are each connected to an exhaust mechanism. As the exhaust mechanism, an appropriate exhaust device may be selected depending on the use of each chamber, and examples of the exhaust mechanism include an exhaust mechanism equipped with a pump having an adsorption means such as a cryopump, a sputter ion pump, or a titanium sublimation pump, and an exhaust mechanism equipped with a turbo molecular pump and a cold trap.

[0102] The procedure for forming a film on a substrate involves placing a substrate 850 or a substrate cassette in a load lock chamber 870 and transporting the substrate 850 or substrate cassette to a mask alignment chamber 891 by a substrate transport mechanism 852. In the mask alignment chamber 891, a mask to be used is picked up from a plurality of masks set in advance and aligned with the substrate on a stage 851. After alignment is complete, a gate 880 is opened and the substrate is transported to a first transport chamber 871 by the substrate transport mechanism 852. The substrate is transported to the first transport chamber 871, and a gate 881 is opened, and the substrate is transported to a second transport chamber 872 by the substrate transport mechanism 853.

[0103] The first film formation chamber 892, which is provided in the second transfer chamber 872 via a gate 882, is a sputtering film formation chamber. The sputtering film formation chamber is provided with a mechanism that can apply a voltage to the sputtering target by switching between an RF power supply and a pulse DC power supply. Two or three types of sputtering targets can be set. In this embodiment, a single crystal silicon target, a sputtering target mainly composed of lithium cobalt oxide (LiCoO2), and a titanium target are set. A substrate heating mechanism is provided in the first film formation chamber 892, and it is also possible to form a film while heating the substrate to a heater temperature of 700°C.

[0104] The negative electrode active material layer can be formed by sputtering using a single crystal silicon target. In addition, a reactive sputtering method using Ar gas and O2 gas is used to form a SiO XThe film formed by sputtering may be used as the negative electrode active material layer. A silicon nitride film formed by reactive sputtering using Ar gas and N2 gas can also be used as a sealing film. A positive electrode active material layer can be formed by sputtering using a sputtering target mainly composed of lithium cobalt oxide (LiCoO2). A conductive film that serves as a current collector can be formed by sputtering using a titanium target. A titanium nitride film formed by reactive sputtering using Ar gas and N2 gas can also be used as a diffusion prevention layer between the current collector layer and the active material layer.

[0105] When forming a positive electrode active material layer, the mask and the substrate are stacked and transported from the second transport chamber 872 to the first film formation chamber 892 by the substrate transport mechanism 853, the gate 882 is closed, and film formation is performed by sputtering. After film formation is completed, the gates 882 and 883 are opened, the substrate is transported to the heating chamber 893, and the gate 883 is closed, after which heating can be performed. For the heating treatment in the heating chamber 893, an RTA (Rapid Thermal Anneal) device, a resistance heating furnace, or a microwave heating device can be used. For the RTA device, a GRTA (Gas Rapid Thermal Anneal) device or a LRTA (Lamp Rapid Thermal Anneal) device can be used. The heating treatment in the heating chamber 893 can be performed under an atmosphere of nitrogen, oxygen, rare gas, or dry air. The heating time is from 1 minute to 24 hours.

[0106] After the film formation or heat treatment is completed, the substrate and mask are returned to the mask alignment chamber 891, and a new mask is aligned. After the alignment is completed, the substrate and mask are transferred to the first transfer chamber 871 by the substrate transfer mechanism 852. The substrate is transported by the lift mechanism of the first transfer chamber 871, and the gate 884 is opened, and the substrate is transported to the third transfer chamber 873 by the substrate transfer mechanism 854.

[0107] The second film formation chamber 874 connected to the third transfer chamber 873 via a gate 885 performs film formation by evaporation.

[0108] An example of the cross-sectional structure of the second film formation chamber 874 is shown in FIG. 10. FIG. 10 is a schematic cross-sectional view cut along the dotted line in FIG. 9. The second film formation chamber 874 is connected to an exhaust mechanism 849, and the first material supply chamber 895 is connected to an exhaust mechanism 848. The second material supply chamber 894 is connected to an exhaust mechanism 847. The second film formation chamber 874 shown in FIG. 10 is an evaporation chamber that performs evaporation using an evaporation source 856 moved from the first material supply chamber 895, and can simultaneously vaporize and deposit a plurality of substances by moving the evaporation sources from a plurality of material supply chambers, that is, co-evaporation. FIG. 10 shows an evaporation source having an evaporation boat 858 also moved from the second material supply chamber 894.

[0109] The second film formation chamber 874 is connected to a second material supply chamber 894 via a gate 886. The second film formation chamber 874 is connected to a first material supply chamber 895 via a gate 888. The second film formation chamber 874 is connected to a third material supply chamber 896 via a gate 887. Therefore, the second film formation chamber 874 is capable of three-source co-evaporation.

[0110] The procedure for performing deposition is as follows: the substrate is placed on the substrate holder 845. The substrate holder 845 is connected to a rotation mechanism 865. Then, the first deposition material 855 is heated to a certain degree in the first material supply chamber 895, and when the deposition rate becomes stable, the gate 888 is opened, and the arm 862 is extended to move the deposition source 856 and stop it at a position below the substrate. The deposition source 856 is composed of the first deposition material 855, a heater 857, and a container for storing the first deposition material 855. Also, the second deposition material is heated to a certain degree in the second material supply chamber 894, and when the deposition rate becomes stable, the gate 886 is opened, and the arm 861 is extended to move the deposition source and stop it at a position below the substrate.

[0111] Thereafter, a shutter 868 and an evaporation source shutter 869 are opened to perform co-evaporation. During evaporation, a rotation mechanism 865 is rotated to improve the uniformity of the film thickness. After evaporation, the substrate is transported to a mask alignment chamber 891 via the same route. When the substrate is to be removed from the manufacturing equipment, it is transported from the mask alignment chamber 891 to a load lock chamber 870 and removed.

[0112] 10 shows an example in which a substrate 850 and a mask are held by a substrate holder 845. The substrate rotation mechanism rotates the substrate 850 (and the mask) to improve the uniformity of the film formation. The substrate rotation mechanism may also function as a substrate transport mechanism.

[0113] Moreover, the second film formation chamber 874 may be provided with an imaging means 863 such as a CCD camera. By providing the imaging means 863, the position of the substrate 850 can be confirmed.

[0114] In the second film formation chamber 874, the thickness of the film formed on the substrate surface can be predicted based on the measurement results of the film thickness measurement mechanism 867. The film thickness measurement mechanism 867 may include, for example, a quartz oscillator.

[0115] In order to control the deposition of the vaporized deposition material, a shutter 868 that overlaps with the substrate until the evaporation rate of the deposition material becomes stable, and a deposition source shutter 869 that overlaps with the deposition source 856 and the deposition boat 858 are provided.

[0116] Although an example of a resistance heating type is shown for the deposition source 856, an EB (Electron Beam) deposition type may be used. Although an example of a crucible is shown as a container for the deposition source 856, an deposition boat may be used. An organic material is placed as a first deposition material 855 in the crucible heated by a heater 857. When pellets or particulate SiO are used as the deposition material, a deposition boat 858 is used. The deposition boat 858 is made up of three parts, a member having a concave surface, an inner lid with two holes, and an upper lid with one hole are stacked on top of each other. The inner lid may be removed for deposition. The deposition boat 858 acts as a resistor when electricity is applied, and the deposition boat itself is heated.

[0117] Further, although the present embodiment shows an example of a multi-chamber system, the present invention is not particularly limited, and an in-line type manufacturing apparatus may also be used.

[0118] (Embodiment 6) 11A is an external view of a thin-film solid-state secondary battery. The secondary battery 913 has a terminal 951 and a terminal 952. The terminal 951 is electrically connected to a positive electrode, and the terminal 952 is electrically connected to a negative electrode. The solid-state secondary battery of one embodiment of the present invention has excellent charge and discharge efficiency. In addition, since the solid-state secondary battery can be an all-solid-state secondary battery, it is also excellent in safety. Thus, the secondary battery of one embodiment of the present invention can be suitably used as the secondary battery 913.

[0119] 11B is an external view of the battery control circuit. The battery control circuit shown in FIG. 11B includes a substrate 900 and a layer 916. A circuit 912 and an antenna 914 are provided over the substrate 900. The antenna 914 is electrically connected to the circuit 912. A terminal 971 and a terminal 972 are electrically connected to the circuit 912. The circuit 912 is electrically connected to a terminal 911.

[0120] The terminal 911 is connected to, for example, a device to which power from the thin-film solid-state secondary battery is supplied, such as a display device, a sensor, or the like.

[0121] The layer 916 has a function of shielding, for example, an electromagnetic field caused by the secondary battery 913. The layer 916 can be made of, for example, a magnetic material.

[0122] 11C shows an example in which the battery control circuit shown in FIG. 11B is disposed on a secondary battery 913. Terminal 971 is electrically connected to terminal 951, and terminal 972 is electrically connected to terminal 952. Layer 916 is disposed between substrate 900 and secondary battery 913.

[0123] The substrate 900 is preferably a flexible substrate.

[0124] A thin battery control circuit can be realized by using a flexible substrate as the substrate 900. In addition, the battery control circuit can be wound around the secondary battery as shown in Fig. 12D described later.

[0125] 12A is an external view of a thin-film solid-state secondary battery. The battery control circuit shown in FIG.

[0126] As shown in FIG. 12C, by bending the substrate 900 to fit the shape of a secondary battery 913 and arranging the battery control circuit around the secondary battery, the battery control circuit can be wrapped around the secondary battery as shown in FIG. 12D.

[0127] (Embodiment 7) In this embodiment, examples of electronic devices using a thin-film solid-state secondary battery will be described with reference to Fig. 13A, Fig. 13B, Fig. 14A, Fig. 14B, and Fig. 14C. The thin-film solid-state secondary battery of one embodiment of the present invention has high discharge capacity and discharge efficiency and is highly safe. Therefore, the electronic device is highly safe and can be used for a long time.

[0128] 13A is a perspective view of the appearance of a thin-film solid secondary battery 3001. A positive electrode lead electrode 513 electrically connected to the positive electrode of the thin-film solid secondary battery and a negative electrode lead electrode 511 electrically connected to the negative electrode are sealed with a laminate film or an insulating film so as to protrude.

[0129] 13B shows an IC card as an example of an application device using the thin-film solid-state secondary battery according to the present invention. Electric power obtained by feeding from radio waves can be charged into a thin-film solid-state secondary battery 3001. An antenna and IC 3004, and a thin-film solid-state secondary battery 3001 are arranged inside the IC card 3000. An ID 3002 and a photo 3003 of a worker who wears the management badge are attached onto the IC card 3000. A signal such as an authentication signal can also be transmitted from the antenna using the power charged in the thin-film solid-state secondary battery 3001.

[0130] Moreover, an active matrix display device may be provided in place of the photograph 3003. Examples of active matrix display devices include reflective liquid crystal display devices, organic EL display devices, and electronic paper. Images (moving or still images) and time can also be displayed on the active matrix display device. Power for the active matrix display device can be supplied from a thin-film solid-state secondary battery 3001.

[0131] Since a plastic substrate is used in an IC card, an organic EL display device using a flexible substrate is preferable.

[0132] A solar cell may be provided in place of the photograph 3003. When exposed to external light, the light is absorbed, electricity is generated, and the electricity can be charged into the thin-film solid secondary battery 3001.

[0133] Furthermore, thin-film solid-state secondary batteries are not limited to use in IC cards, but can also be used as power sources for wireless sensors mounted on vehicles, secondary batteries for MEMS devices, and the like.

[0134] FIG. 14A shows an example of a wearable device. The wearable device uses a secondary battery as a power source. In order to improve water resistance in daily use or outdoor use, a wearable device that can be charged wirelessly as well as by wire with an exposed connector is desired.

[0135] For example, a thin-film solid-state secondary battery can be mounted on a glasses-type device 400 as shown in FIG. 14A. The glasses-type device 400 has a frame 400a and a display unit 400b. By mounting a secondary battery on the temples of the curved frame 400a, the glasses-type device 400 can be made lightweight, well-balanced in weight, and capable of long continuous use. The solid-state secondary battery shown in the first embodiment may be provided, and a configuration that can accommodate space saving associated with a smaller housing can be realized.

[0136] Also, it can be mounted in a headset type device 401. Headset type device 401 has at least microphone section 401a, flexible pipe 401b, and earphone section 401c. A secondary battery can be provided in flexible pipe 401b or earphone section 401c. The solid-state secondary battery shown in the first embodiment may be provided, and a configuration that can accommodate space saving associated with a smaller casing can be realized.

[0137] Moreover, it can be mounted on a device 402 that can be directly attached to the body. A secondary battery 402b can be provided in a thin housing 402a of the device 402. The solid-state secondary battery shown in the first embodiment may be provided, and a configuration that can accommodate space saving due to the miniaturization of the housing can be realized.

[0138] Moreover, it can be mounted on a device 403 that can be attached to clothing. A secondary battery 403b can be provided in a thin housing 403a of the device 403. The solid-state secondary battery shown in the first embodiment may be provided, and a configuration that can accommodate space saving due to the miniaturization of the housing can be realized.

[0139] Also, it can be mounted on a belt type device 406. The belt type device 406 has a belt part 406a and a wireless power supply receiving part 406b, and a secondary battery can be mounted inside the belt part 406a. The solid secondary battery shown in the first embodiment may be provided, and a configuration that can accommodate space saving due to the miniaturization of the housing can be realized.

[0140] The device can be mounted on a wristwatch type device 405. The wristwatch type device 405 has a display unit 405a and a belt unit 405b, and a secondary battery can be provided on the display unit 405a or the belt unit 405b. The solid-state secondary battery shown in the fourth embodiment may be provided, and a configuration capable of saving space due to the miniaturization of the housing can be realized.

[0141] Display unit 405a can display not only the time, but also various other information such as incoming e-mails and phone calls.

[0142] In addition, since the wristwatch type device 405 is a wearable device that is directly wrapped around the arm, it may be equipped with sensors that measure the user's pulse, blood pressure, etc. Data on the user's amount of exercise and health can be accumulated to manage the user's health.

[0143] FIG. 14B shows a perspective view of the wristwatch type device 405 removed from the wrist.

[0144] 14C shows a side view of the display portion 405. FIG. 14C shows a state in which a secondary battery 913 is built in the display portion 405. The secondary battery 913 is the secondary battery described in Embodiment 4. The secondary battery 913 is provided at a position overlapping with the display portion 405a, and is small and lightweight.

[0145] (Embodiment 8) The device described in this embodiment has at least a biosensor and a solid-state secondary battery that supplies power to the biosensor, and can obtain various types of bioinformation using infrared light and visible light and store the information in a memory. Such bioinformation can be used for both personal authentication of users and health care. The solid-state secondary battery of one embodiment of the present invention has high discharge capacity and discharge efficiency, and is also highly safe. Therefore, the device is highly safe and can be used for a long period of time.

[0146] A biosensor is a sensor that acquires biological information, and acquires biological information that can be used for healthcare purposes. The biological information includes pulse wave, blood glucose level, oxygen saturation, triglyceride concentration, etc. The data is stored in a memory.

[0147] Furthermore, it is preferable to provide a means for acquiring other biological information in the device described in this embodiment. For example, in addition to internal biological information such as electrocardiogram, blood pressure, and body temperature, there is superficial biological information such as facial expression, complexion, and pupils. Information on the number of steps, exercise intensity, elevation change, and diet (calories ingested, nutrients, etc.) are also important information for health care. Using multiple biological information enables comprehensive health management, which leads not only to daily health management but also to early detection of injuries and illnesses.

[0148] For example, blood pressure can be calculated from an electrocardiogram and the difference in timing between the two beats of a pulse wave (length of pulse wave propagation time). High blood pressure results in a short pulse wave propagation time, and conversely, low blood pressure results in a long pulse wave propagation time. The relationship between heart rate and blood pressure calculated from an electrocardiogram and pulse wave can also be used to estimate the user's physical condition. For example, if both the heart rate and blood pressure are high, it can be estimated that the user is in a state of tension or excitement, and conversely, if both the heart rate and blood pressure are low, it can be estimated that the user is in a relaxed state. Furthermore, if the user continues to have low blood pressure and a high heart rate, this may be a sign of heart disease.

[0149] Users can check their own physical condition estimated based on the biometric information measured by electronic devices at any time, which will improve their health awareness. As a result, they may be prompted to review their daily habits, such as avoiding overeating and drinking, taking appropriate exercise, and managing their physical condition, and may even be prompted to receive a medical examination if necessary.

[0150] Each data may be shared among multiple biosensors. Fig. 15A shows an example in which a biosensor 80a is embedded in a user's body and an example in which a biosensor 80b is attached to the user's wrist. Fig. 15A shows a device having a biosensor 80a capable of measuring an electrocardiogram, for example, and a device having a biosensor 80b capable of measuring a user's heart rate by optically monitoring the pulse of the user's arm. Note that the wearable device of the watch or wristband type shown in Fig. 15A is not limited to measuring a heart rate, and various biosensors can be used.

[0151] 15A is premised on being small, generating almost no heat, and causing no allergic reactions when it comes into contact with the skin. The secondary battery used in the device of one embodiment of the present invention is suitable because it is small, generates almost no heat, and causes no allergic reactions. In addition, it is preferable that the embedded device has a built-in antenna so that it can be wirelessly charged.

[0152] The device of the type implanted in a living body shown in FIG. 15A is not limited to a biosensor capable of measuring an electrocardiogram, and a biosensor capable of acquiring other biological data can be used.

[0153] The biosensor 80b built into the device may be temporarily stored in a memory built into the device. Alternatively, the data acquired by the biosensors may be sent wirelessly or via wire to a portable data terminal 85 in FIG. 15B, and the waveform may be detected by the portable data terminal 85. The portable data terminal 85 is a smartphone or the like, and can detect whether a problem such as arrhythmia has occurred from the data acquired from each biosensor. When sending data acquired by multiple biosensors to the portable data terminal 85 via wire, it is preferable to transfer the acquired data acquired before connecting via wire together. Each detected data may be automatically assigned a date and stored in the memory of the portable data terminal 85, and managed personally. Alternatively, the data may be sent to a medical institution 87 such as a hospital via a network (including the Internet) as shown in FIG. 15B. The data is managed by a data server of the hospital, and can be used as test data during treatment. Since the amount of medical data may be huge, a network including Bluetooth (registered trademark) or a frequency band of 2.4 GHz to 2.4835 GHz may be used from the biosensor 80b to the portable data terminal 85, and a fifth-generation (5G) wireless system may be used from the portable data terminal 85 to the portable data terminal 85 for high-speed communication. The fifth-generation (5G) wireless system uses frequencies of 3.7 GHz, 4.5 GHz, and 28 GHz. By using the fifth-generation (5G) wireless system, data can be acquired and transmitted to a medical institution 87 not only at home but also when going out, and data when the user's physical condition is abnormal can be accurately acquired and used for subsequent processing or treatment. The configuration shown in FIG. 15C can be used as the portable data terminal 85.

[0154] 15C shows another example of a portable data terminal 89. The portable data terminal 89 has a speaker, a pair of electrodes 83, a camera 84, and a microphone 86 in addition to a secondary battery.

[0155] A pair of electrodes 83 are provided on a part of the housing 82, sandwiching the display unit 81a. The display unit 81b is a region having a curved surface. The electrodes 83 function as electrodes for acquiring an electrocardiogram.

[0156] As shown in FIG. 15C, by arranging a pair of electrodes 83 in the longitudinal direction of housing 82, when using portable data terminal 89 with a landscape screen, an electrocardiogram can be obtained without the user being aware of it.

[0157] 1 shows an example of a usage state of a portable data terminal 89. The display unit 81a can display electrocardiogram information 88a acquired by a pair of electrodes 83, heart rate information 88b, and the like.

[0158] When biosensor 80a is embedded in the user's body as shown in Fig. 15A, this function is unnecessary, but when biosensor 80a is not embedded, the user can obtain an electrocardiogram by holding a pair of electrodes 83 with both hands. Even when biosensor 80a is embedded in the user's body, portable data terminal 89 shown in Fig. 15C can be used to compare electrocardiogram data with that of other users to check whether biosensor 80a is functioning normally.

[0159] The camera 84 can capture an image of the user's face, etc. From the image of the user's face, biological information such as facial expression, pupils, and complexion can be obtained.

[0160] The microphone 86 can acquire the user's voice. Voiceprint information that can be used for voiceprint authentication can be acquired from the acquired voice information. In addition, voice information can be acquired periodically and changes in voice quality can be monitored for use in health management. Of course, the microphone 86, camera 84, and speaker can also be used to make a videophone call with a doctor at a medical institution 87.

[0161] By using the device shown in FIG. 15A and the portable data terminal 89 shown in FIG. 15C, a remote medical support system can be realized in which information can be sent from a remote location to a doctor in a hospital and the patient can receive medical treatment from the doctor. EXAMPLES

[0162] The crystallinity of the undercoat film and the positive electrode active material in the solid secondary battery according to one embodiment of the present invention will be described. Each sample was fabricated by a sputtering method in a chamber at 600° C. The structure and fabrication conditions of each sample are shown in Table 1.

[0163] [Table 1]

[0164] <Preparation of Comparative Sample 1> A LiCoO2 film was formed to a thickness of 1000 nm on a titanium sheet. Comparative sample 1 differs from samples 2 and 3 described below only in the presence or absence of an undercoat film.

[0165] <Preparation of Sample 2 and Sample 3> A TiN film was formed on a titanium sheet with a thickness of 100 μm, and a LiCoO2 film of 1000 nm was formed on the TiN. A TiN film of 20 nm was formed in Sample 2, and a LiCoO2 film of 40 nm was formed in Sample 3. In the solid secondary battery, the titanium sheet functions as a substrate and a positive electrode current collector layer, TiN functions as an undercoat film, and LiCoO2 functions as a positive electrode active material. As described above, when TiN is used as the undercoat film and LiCoO2 is used as the positive electrode active material layer, the value of the above formula (1) is approximately 0.06.

[0166] <Evaluation of crystallinity of each sample> XRD (X-ray diffraction) measurements were performed to evaluate the crystallinity of each sample. The measurement was performed at room temperature using a BRUKER D8 ADVANCE measuring device. The results are shown in Figure 16.

[0167] In FIG. 16, the half-width of the peak at about 19° originating from (003) of LiCoO2 of each sample was 0.137° for comparative sample 1, 0.125° for sample 2, and 0.120° for sample 3. In this specification, the smaller the half-width of the peak in the XRD measurement, the higher the crystallinity of the sample is evaluated. That is, it was found that samples 2 and 3 have higher crystallinity than comparative sample 1. Therefore, by introducing the undercoat film, the crystallinity of the positive electrode active material layer can be improved. Also, it can be said that sample 3 has better crystallinity than sample 2. Therefore, it can be said that the undercoat film has higher crystallinity of LiCoO2 than 20 nm. This is thought to be because the thicker the film, the higher the crystallinity of TiN, and the LiCoO2 formed on the (111) of TiN is more likely to have (003).

[0168] <Battery cell production> Next, each sample was used as a positive electrode to fabricate a CR2032 type coin-type battery cell (diameter 20 mm, height 3.2 mm).

[0169] Lithium metal was used as the counter electrode.

[0170] The electrolyte used in the electrolytic solution was 1 mol / L lithium hexafluorophosphate (LiPF6), and the electrolytic solution was a mixture of ethylene carbonate (EC) and diethyl carbonate (DEC) at a volume ratio of EC:DEC = 3:7. For the secondary batteries used to evaluate the charge / discharge efficiency, 2 wt% vinylene carbonate (VC) was added to the electrolytic solution.

[0171] The separator was made of polypropylene having a thickness of 25 μm.

[0172] The positive electrode can and the negative electrode can were made of stainless steel (SUS).

[0173] <Measurement of charge / discharge efficiency> The initial characteristics were measured by charging at CCCV, 0.2C, 4.2V, and a cutoff current of 0.1C. The charging method of the lithium ion secondary battery is generally CCCV charging. CCCV charging is a charging method in which the battery is first charged to a predetermined voltage by CC charging, and then charged until the current flowing by CV charging decreases, specifically until the battery reaches the end current value. One charging period is divided into a CC charging period (also called CC time) and a subsequent CV charging period (CV time). In the CC charging period, a constant current is passed through the secondary battery until a predetermined voltage is reached, and in the CV charging period, the battery is charged at a constant voltage until the battery reaches the end current value. In this embodiment, the battery was discharged at CC, 0.2C, and a cutoff voltage of 2.5V. Here, 1C is a current value of 137mA / g per weight of the positive electrode active material. The measurement temperature was 25°C. The results of measuring the initial characteristics are shown in Table 2 and Figs. 17A and 17B. FIG. 17B is an enlarged view of the portion after 100 (mAh / g) in FIG. 17A.

[0174] [Table 2]

[0175] From Table 2 and Figures 17A and 17B, it was found that Sample 2 and Sample 3 have higher discharge capacity and charge / discharge efficiency than Comparative Sample 1. It was also found that Sample 3 has higher discharge capacity and charge / discharge efficiency than Sample 2. These results are because the crystallinity of LiCoO2 is higher in Sample 2 than Comparative Sample 1, and the crystallinity of LiCoO2 is higher in Sample 3 than Sample 2. Also, when focusing on the region of 0 (mAh / g) to 100 (mAh / g) in Figure 17A, it can be seen that the voltages are the same for each sample. Therefore, it was found that introducing TiN, which is an undercoat film, between the Ti sheet and LiCoO2 does not adversely affect the battery characteristics. In other words, it can be said that TiN is a material with good conductivity.

[0176] Therefore, it was found that the introduction of an underlayer film can produce a secondary battery with good charge-discharge characteristics. It was also found that a thickness of 40 nm for the underlayer film is more preferable than a thickness of 20 nm. [Explanation of symbols]

[0177] 101: substrate, 150: solid secondary battery, 152: solid secondary battery, 154: solid secondary battery, 156: solid secondary battery, 158: solid secondary battery, 200: single layer cell, 201: positive electrode collector layer, 202: positive electrode active material layer, 203: solid electrolyte layer, 204: negative electrode active material layer, 205: negative electrode collector layer, 206: protective layer, 210: undercoat film, 211: solid electrolyte layer, 212: positive electrode collector layer, 213: positive electrode collector, 214: positive electrode collector layer, 216: positive electrode collector layer, 400: eyeglass-type device, 400a: frame, 400b: display unit, 4 01: headset type device, 401a: microphone section, 401b: flexible pipe, 401c: earphone section, 402: device, 402a: housing, 402b: secondary battery, 403: device, 403a: housing, 403b: secondary battery, 405: wristwatch type device, 405a: display section, 405b: belt section, 406: belt type device, 406a: belt section, 406b: wireless power supply receiving section, 511: negative electrode lead electrode, 513: positive electrode lead electrode, 845: substrate holding section, 847: exhaust mechanism, 848: exhaust mechanism, 849: exhaust mechanism, 850: substrate, 851: stage, 852: substrate transport mechanism, 853: substrate transport mechanism, 854: substrate transport mechanism, 855: deposition material, 856: deposition source, 857: heater, 858: deposition boat, 861: arm, 862: arm, 863: imaging means, 865: rotation mechanism, 867: film thickness measurement mechanism, 868: shutter, 869: deposition source shutter, 870: load lock chamber, 871: transport chamber, 872: transport chamber, 873: transport chamber, 874: film formation chamber, 880: gate, 881: gate, 882: gate, 883: gate, 884: gate, 885: gate, 886: gate, 887: gate, 888: gate, 891: mask alignment chamber, 892: deposition chamber, 893: heating chamber, 894: material supply chamber, 895: material supply chamber, 896: material supply chamber, 900: substrate, 911: terminal, 912: circuit, 913: secondary battery, 914: antenna, 916: layer, 951: terminal, 952: terminal, 971: terminal, 972: terminal, 3000: IC card, 3001: thin-film secondary battery, 3002: ID, 3003: photo, 3004: IC

Claims

1. A positive electrode current collector layer; an undercoat film on the positive electrode current collector layer; a positive electrode active material layer on the undercoat film; a solid electrolyte layer on the positive electrode active material layer; a negative electrode active material layer on the solid electrolyte layer; a negative electrode current collector layer on the negative electrode active material layer, a second electrode layer formed on the first electrode and a second electrode layer formed on the second electrode, the second electrode being electrically connected to the first electrode and the second electrode layer.

2. A positive electrode current collector layer; an undercoat film on the positive electrode current collector layer; a positive electrode active material layer on the undercoat film; a solid electrolyte layer on the positive electrode active material layer; a negative electrode active material layer on the solid electrolyte layer; a negative electrode current collector layer on the negative electrode active material layer, the solid electrolyte layer has an area in contact with a side surface of the positive electrode active material layer and a side surface of the positive electrode current collector layer.

3. In claim 1 or 2, The positive electrode current collector layer and the undercoat film comprise the same metal.

4. In any one of claims 1 to 3, The positive electrode current collector layer comprises titanium.

5. In any one of claims 1 to 4, The secondary battery, wherein the undercoat film comprises titanium.

6. In any one of claims 1 to 5, The positive electrode active material layer comprises lithium cobalt oxide.

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