阅读说明：本技术 全固体电池 (All-solid-state battery ) 是由 上野哲也 矶道岳步 益子泰辅 于 2019-03-19 设计创作，主要内容包括：该全固体电池具有：正极层,其由正极集电体层和设置于上述正极集电体层上的正极活性物质层构成；负极层,其由负极集电体层和设置于上述负极集电体层上的负极活性物质层构成；以及固体电解质层,其配置于上述正极层与上述负极层之间,且具有固体电解质,上述全固体电池具有上述正极层和上述负极层经由上述固体电解质层相对的蓄电部和外装部,上述外装部的离子传导率为10<Sup>-2</Sup>S/cm以下。(The all-solid-state battery includes: a positive electrode layer including a positive electrode collector layer and a positive electrode active material layer provided on the positive electrode collector layer; a negative electrode layer including a negative electrode collector layer and a negative electrode active material layer provided on the negative electrode collector layer; and a solid electrolyte layer which is disposed between the positive electrode layer and the negative electrode layer and has a solid electrolyte, wherein the all-solid-state battery includes a power storage unit and an exterior unit in which the positive electrode layer and the negative electrode layer face each other via the solid electrolyte layer, and the exterior unit has an ion conductivity of 10 ‑2 S/cm or less.)

1. An all-solid-state battery in which,

comprising:

a positive electrode layer including a positive electrode collector layer and a positive electrode active material layer provided on the positive electrode collector layer;

a negative electrode layer including a negative electrode collector layer and a negative electrode active material layer provided on the negative electrode collector layer; and

A solid electrolyte layer disposed between the positive electrode layer and the negative electrode layer and having a solid electrolyte,

the all-solid-state battery includes a power storage unit in which the positive electrode layer and the negative electrode layer face each other with the solid electrolyte layer interposed therebetween,

the ion conductivity of the exterior part is 10^-2S/cm or less.

2. The all-solid battery according to claim 1,

a ratio Y of the ionic conductivity of the exterior portion to the ionic conductivity of the solid electrolyte layer is 0. ltoreq. Y.ltoreq.1, wherein Y is the ionic conductivity of the exterior portion/the ionic conductivity of the solid electrolyte layer.

3. The all-solid battery according to claim 1 or 2,

the ratio Y of the ionic conductivity of the exterior part to the ionic conductivity of the solid electrolyte layer is 10^-6Y ≦ 1, where Y ═ the ionic conductivity of the exterior portion/the ionic conductivity of the solid electrolyte layer.

4. The all-solid battery according to any one of claims 1 to 3,

the exterior portion is formed in at least a part of the all-solid battery other than the power storage portion.

5. The all-solid battery according to any one of claims 1 to 4,

The exterior part is at least one selected from oxides, oxides of alloys, phosphates, sulfides, polyanion compounds and glass.

6. The all-solid battery according to any one of claims 1 to 5,

the electronic conductivity of the exterior part is 10^-9S/cm or less.

7. The all-solid battery according to any one of claims 1 to 6,

the void ratio P of the exterior part is 0.4 or less.

Technical Field

The present invention relates to an all-solid battery. The present application claims priority on japanese patent application No. 2018-.

Background

In recent years, lithium ion secondary batteries have been widely used as power sources for mobile communication devices such as mobile phones and smart phones, and portable small-sized devices such as notebook personal computers, tablet PCs, and game machines. Lithium ion secondary batteries used in such small portable devices are required to be compact, thin and have improved reliability. In order to drive these electronic devices for a long time, research and development of lithium ion secondary batteries with a long life and a high capacity are actively being carried out.

As lithium ion secondary batteries, batteries using an organic electrolytic solution as an electrolyte and batteries using a solid electrolyte are known. Conventionally, a lithium ion secondary battery using an organic electrolytic solution as an electrolyte is formed by coating a positive electrode and a negative electrode, each having a positive electrode active material or a negative electrode active material that adsorbs and releases lithium ions, on both surfaces of a sheet-like current collector made of aluminum, copper, or the like, winding these positive electrode and negative electrode a plurality of times with a separator interposed therebetween to form a wound body, and sealing the wound body together with the electrolytic solution in an outer casing having a shape of a cylinder, a square, a button, or the like.

In such a lithium ion secondary battery, the electrolyte solution contains a flammable organic solvent. Therefore, there is a case where liquid leakage or short circuit occurs due to the application of an impact, and abnormal heat generation occurs. Therefore, a battery having more excellent safety is desired.

In a lithium ion secondary battery (all-solid-state battery) using a solid electrolyte as an electrolyte, the degree of freedom in designing the shape of the battery is high, and the battery size and thickness can be easily reduced, as compared with a lithium ion secondary battery using an organic electrolyte solution. Further, the all-solid-state battery does not contain an electrolytic solution, and therefore has an advantage of high reliability without causing leakage, abnormal heat generation, and the like.

The all-solid batteries are mainly classified into two types, i.e., a film type all-solid battery and a bulk (bulk) type all-solid battery. The thin film type all-solid battery is manufactured by a thin film technique such as a PVD method or a sol-gel method. The block-type all-solid battery is manufactured by powder molding of an electrode active material or a sulfide-based solid electrolyte.

The thin film type all-solid battery has a small battery capacity because it is difficult to thicken or laminate an active material layer at a high level. In addition, the manufacturing cost of the thin film type all-solid battery is high.

The bulk all-solid battery uses a sulfide-based solid electrolyte. The sulfide-based solid electrolyte layer generates hydrogen sulfide upon reaction with water. Therefore, the block-type all-solid secondary battery needs to be manufactured in a glove box for managing a dew point. In addition, it is difficult to form a sheet of the sulfide solid electrolyte. Therefore, it is difficult to make the solid electrolyte layer thin and to stack the cells high in the bulk all-solid battery.

Patent documents 1 and 2 disclose a method for manufacturing an industrially applicable all-solid-state battery, which has been completed in view of the above circumstances. The method for manufacturing the all-solid-state battery disclosed in patent documents 1 and 2 performs the following method: the respective members are formed into sheets using an oxide-based solid electrolyte stable in air, stacked, and then fired simultaneously.

Specifically, the method for manufacturing an all-solid battery described in patent document 1 discloses a method in which an electrode layer sheet and a solid electrolyte sheet are stacked and fired, and then heated at 100 ℃ to remove moisture, thereby producing a fired laminate. Next, a polymethyl methacrylate resin gel compound was applied to a metal lithium plate, and the applied surface was attached to the surface of the fired laminate on the solid electrolyte layer side, and the laminate was sealed with a 2032 type coin cell to produce an all-solid-state battery.

Patent document 2 discloses a method for producing an all-solid-state battery having a laminated structure of a positive electrode current collector, a positive electrode, a part of a solid electrolyte layer, a solid electrolyte layer and a negative electrode, and a negative electrode current collector in this order from the plane of paper.

Disclosure of Invention

Technical problem to be solved by the invention

However, the all-solid-state battery described in patent document 1 cannot effectively function when moisture intrudes, and therefore attempts have been made to reduce the intrusion of moisture by using a 2032 type coin cell. However, moisture contained in the atmosphere at the time of sealing or moisture contained in the polymethyl methacrylate resin gel exists inside the seal. In addition, since dehumidification or the like of the 2032 type coin cell sealing material itself is not performed, moisture is present inside the seal. That is, the all-solid-state battery disclosed in patent document 1 may react with components (mainly moisture) in the atmosphere in the positive electrode layer or the negative electrode layer after charging, and cause self-discharge.

The all-solid battery shown in patent document 2 is also likely to cause self-discharge. That is, the self-discharge characteristics of the all-solid-state batteries described in patent documents 1 and 2 are insufficient.

The present invention has been made in view of the above-described problems, and an object thereof is to provide an all-solid-state battery having high self-discharge characteristics.

Means for solving the technical problem

One embodiment of the present invention provides an all-solid-state battery including: a positive electrode layer including a positive electrode collector layer and a positive electrode active material layer provided on the positive electrode collector layer; a negative electrode layer including a negative electrode collector layer and a negative electrode active material layer provided on the negative electrode collector layer; a solid electrolyte layer disposed between the positive electrode layer and the negative electrode layer and having a solid electrolyte, wherein the all-solid-state battery includes a power storage unit and an exterior unit that are opposed to each other with the positive electrode layer and the negative electrode layer interposed therebetween, and the exterior unit has an ion conductivity of 10^-2S/cm or less.

According to the above configuration, by providing the exterior portion, the chance of the positive electrode active material layer or the negative electrode active material layer in a charged state being exposed to components (mainly moisture) in the atmosphere is reduced, and thereby the generation of energy consumed in the reaction with the components in the atmosphere can be suppressed.

Further, the ion conductivity of the exterior part was set to 10^-2S/cm or less, and the deflection of lithium ions in the exterior part during charging can be reduced. This makes it possible to suppress leakage current caused by relaxation of the deflection of lithium ions in the exterior part in the open state after charging. This can improve the self-discharge characteristics.

The self-discharge rate of the all-solid battery is preferably 6.5% or less, more preferably 6% or less, and further preferably 5% or less.

In the all-solid-state battery of the above aspect, the ratio Y (ionic conductivity of the exterior portion)/(ionic conductivity of the solid electrolyte layer) between the ionic conductivity of the exterior portion and the ionic conductivity of the solid electrolyte layer may be Y ≦ 1.

According to the above configuration, when the ratio Y (ion conductivity of the exterior portion)/(ion conductivity of the solid electrolyte layer) of the ion conductivity of the exterior portion to the ion conductivity of the solid electrolyte layer is Y ≦ 1, charging can be completed before the deflection of lithium ions in the exterior portion at the time of charging becomes large, and the deflection of lithium ions in the exterior portion can be reduced. This can further suppress leakage current due to relaxation of the deflection of lithium ions in the exterior part in the open state after charging, and can further improve self-discharge characteristics.

In the all-solid-state battery of the above-described aspect, the ratio Y (ionic conductivity of the exterior portion)/(ionic conductivity of the solid electrolyte layer) of the ionic conductivity of the exterior portion to the ionic conductivity of the solid electrolyte layer may be 0. ltoreq. y.ltoreq.1.

According to the above configuration, by configuring the all-solid-state battery such that the ratio of the ion conductivity of the exterior portion to the ion conductivity of the solid electrolyte layer constituting the power storage portion is 0. ltoreq. Y.ltoreq.1, it is possible to complete charging before the deflection of lithium ions in the exterior portion becomes large, and it is possible to further reduce the deflection of lithium ions in the exterior portion. This can further suppress leakage current due to relaxation of the deflection of lithium ions in the exterior part in the open state after charging, and can further improve self-discharge characteristics.

In the all-solid-state battery of the above-described aspect, the ratio Y (ion conductivity of the exterior portion)/(ion conductivity of the solid electrolyte layer) of the ion conductivity of the exterior portion to the ion conductivity of the solid electrolyte layer may be 10^-6≤Y≤1。

According to the above configuration, the ratio of the ion conductivity of the exterior portion to the ion conductivity of the solid electrolyte layer constituting the power storage portion is 10 ^-6The structure of the all-solid-state battery such that Y is not more than 1 can further complete charging before the deflection of lithium ions in the exterior portion becomes large, and can further reduce the deflection of lithium ions in the exterior portion. This can further suppress leakage current due to relaxation of the deflection of lithium ions in the exterior part in the open state after charging, and can further improve self-discharge characteristics.

In the all-solid-state battery according to the above aspect, the exterior portion may be configured as at least a part of the all-solid-state battery other than the power storage portion.

According to the above configuration, by providing the exterior portion in at least a part of the all-solid-state battery other than the power storage portion, the chance of exposure of the positive electrode active material layer or the negative electrode active material layer in a charged state to components (mainly moisture) in the atmosphere can be further reduced, and the deflection of lithium ions in the exterior portion during charging can be further reduced. By this, the self-discharge characteristics can be further improved.

In the all-solid-state battery according to the above aspect, the exterior portion may be at least one selected from the group consisting of an oxide, an oxide of an alloy, a phosphate, a sulfide, a polyanion compound, and glass.

According to the above configuration, it is possible to suppress deviation of lithium ions in the exterior part, to form a good joint between the exterior part and the power storage part, to suppress a crack caused by a joint failure, to suppress entry of a component in the atmosphere from the crack, and to suppress generation of energy consumed when the positive electrode active material layer or the negative electrode active material layer reacts with the component in the atmosphere. This can further improve the self-discharge characteristics.

The electronic conductivity of the exterior part of the all-solid-state battery of the above-described embodiment may be 10^-9S/cm or less.

According to the above configuration, even in a state where the deviation of lithium ions in the exterior portion is suppressed and the potential difference of the open circuit occurs during charging, discharging, or after charging, the exterior portion can be kept in a good insulating state of electrons, and the short circuit between the exterior portion and the power storage portion can be suppressed. This can further improve the self-discharge characteristics.

The porosity P of the exterior portion of the all-solid battery of the above embodiment may be 0.4 or less.

According to the above configuration, by setting the porosity of the exterior part to the range, it is possible to suppress deviation of lithium ions in the exterior part and to establish more favorable bonding with the power storage element.

Effects of the invention

According to the present invention, an all-solid-state battery having high self-discharge characteristics can be provided.

Drawings

Fig. 1 is a schematic cross-sectional view schematically showing an example of an all-solid battery according to an embodiment of the present invention.

Fig. 2 is a schematic cross-sectional view schematically showing an example of an all-solid battery according to an embodiment of the present invention.

Fig. 3 is a schematic cross-sectional view schematically showing an example of a power storage unit according to an embodiment of the present invention.

Description of the symbols

50: all-solid-state battery

51: exterior part

52: positive collector layer

53: positive electrode active material layer

54: negative collector layer

55: negative electrode active material layer

56: solid electrolyte layer

57: terminal electrode

60: all-solid-state battery

61: exterior part

62: positive collector layer

63: positive electrode active material layer

64: negative collector layer

65: negative electrode active material layer

66: solid electrolyte layer

67: terminal electrode

10: power storage unit

11: positive collector layer

12: positive electrode active material layer

13: negative collector layer

14: negative electrode active material layer

15: solid electrolyte layer

Detailed Description

Preferred examples of embodiments of the all-solid-state battery and the power storage unit according to the present invention will be described below in detail with reference to the accompanying drawings. In the drawings used in the following description, for the sake of easy understanding of the features of the present embodiment, the portions to be the features may be shown enlarged, and the dimensional ratios of the respective components may be different from those in reality. The materials, dimensions, and the like exemplified in the following description are examples, and the present invention is not limited to these examples, and can be implemented by appropriately changing the materials, dimensions, and the like within a range not changing the gist thereof. That is, the present invention is not limited to the embodiments described below, and can be implemented with appropriate modifications within a range that achieves the effects thereof. For example, the number of pairs, numerical values, amounts, ratios, shapes, positions, characteristics, and the like may be omitted, added, or changed without departing from the scope of the present invention.

A preferred example of the all-solid battery according to the first embodiment will be described below with reference to fig. 1.

Fig. 1 is a schematic cross-sectional view schematically showing a cross section of an example of the all-solid battery according to the first embodiment. The all-solid battery 50 shown in fig. 1 has: exterior portion 51, positive electrode collector layer 52, positive electrode active material layer 53, negative electrode collector layer 54, negative electrode active material layer 55, solid electrolyte layer 56, and terminal electrode 57. The all-solid battery 50 has a structure in which a positive electrode collector layer 52, a positive electrode active material layer 53, a negative electrode collector layer 54, a negative electrode active material layer 55, and a solid electrolyte layer 56 are laminated, and has one or more power storage units. The exterior portion 51 is disposed so as to cover the power storage unit except for the portion connected to the terminal electrode 57.

In the all-solid battery 50 shown in fig. 1, the positive electrode collector layers 52 are sometimes referred to as positive electrode active materials 52c, 52b, and 52a in order of the stacking direction, for convenience. Similarly, the positive electrode active material layers 53 are referred to as 53c2, 53c1, 53b2, 53b1, and 53a1, the negative electrode collector layers 54 are referred to as 54a, 54b, and 54c, and the positive electrode active material layers 55 are referred to as 55a1, 55a2, 55b1, 55b2, 55c1, and 55c2, respectively. The positive electrode current collector layer 52 and the positive electrode active material layer 53 disposed on one or both of the principal surfaces thereof may be collectively referred to as a positive electrode layer 523. For convenience, the positive electrode layers 523c, 523b, and 523a are oriented in the stacking direction, respectively. Similarly, the negative electrode collector layer 55 and the negative electrode active material layer 54 disposed on one or both principal surfaces thereof may be collectively referred to as a negative electrode layer 545. The respective directions toward the lamination of the negative electrode layers 545 may be 545a, 545b, and 545 c. The outermost portion of the power storage unit of the all-solid battery 50 is constituted by the positive electrode collector layer 52a and the negative electrode collector layer 54 a.

An intermediate layer for relaxing the thermal expansion coefficient may be provided between at least one of positive electrode active material layer 53 and solid electrolyte layer 56 and between at least one of negative electrode active material layer 55 and solid electrolyte layer 56.

The positive electrode active material layer 53 is provided on at least one side of the main surface of the positive electrode collector layer 52, or may be provided on both sides. For example, in fig. 1, the positive electrode active material layer 53a is provided on one main surface of the positive electrode current collector layer 52a, and the positive electrode active material layers 53b1 and 53b2 are provided on both main surfaces of the positive electrode active material layer 52 b.

The negative electrode active material layer 55 is provided on at least one side of the negative electrode collector layer 54, and may be provided on both sides. For example, in fig. 1, the positive electrode active material layer 55a is provided on one main surface of the positive electrode current collector layer 54a, the positive electrode active material layer 54b is provided, and the positive electrode active material layers 55b1 and 55b2 are provided on both main surfaces.

Each positive electrode collector layer 52 and each negative electrode collector layer 54 are connected to different terminal electrodes 57. The all-solid battery 50 can be electrically connected to the outside by connecting the positive electrode current collector layer 52 to the terminal electrode 57 and connecting the negative electrode current collector layer 54 to the terminal electrode 57.

Fig. 2 is a schematic cross-sectional view schematically showing a cross section of an example of the all-solid battery according to the second embodiment. As shown in fig. 2, the all-solid battery 60 includes: exterior section 61, positive electrode collector layer 62, positive electrode active material layer 63, negative electrode collector layer 64, negative electrode active material layer 65, solid electrolyte layer 66, and terminal electrode 67. The all-solid battery 60 includes: exterior section 61, positive electrode collector layer 62, positive electrode active material layer 63, negative electrode collector layer 64, negative electrode active material layer 65, solid electrolyte layer 66, and terminal electrode 67. The all-solid battery 60 has a structure in which a positive electrode collector layer 62, a positive electrode active material layer 63, a negative electrode collector layer 64, a negative electrode active material layer 65, and a solid electrolyte layer 66 are laminated, and has one or more power storage units. The outermost portion of the power storage unit in the all-solid battery 60 is constituted by the positive electrode active material layer 63a and the negative electrode active material layer 65 a. The exterior portion 61 is disposed so as to cover the power storage unit except for a portion connected to the terminal 67.

Further, an intermediate layer for relaxing the thermal expansion coefficient may be provided between at least one of the positive electrode active material layer 63 and the solid electrolyte 66, and between the negative electrode active material layer 65 and the solid electrolyte 66.

Each positive electrode collector layer 62 and each negative electrode collector layer 64 are connected to different terminal electrodes 67. With this configuration, the connector can be electrically connected to the outside.

Fig. 3 is a sectional view showing an example of the power storage unit according to the present embodiment. As shown in fig. 3, power storage unit 10 includes: the positive electrode current collector layer 11, the positive electrode active material layer 12, the negative electrode current collector layer 13, the negative electrode active material layer 14, and the solid electrolyte layer 15 are each stacked.

In the present embodiment, the all-solid-state battery 50 is preferably an all-solid-state battery having a power storage unit and an exterior unit, the power storage unit including: a positive electrode layer comprising a positive electrode current collector layer 52 and a positive electrode active material layer 53 provided on the positive electrode current collector layer 52, a negative electrode layer comprising a negative electrode current collector layer 54 and a negative electrode active material layer 55 provided on the negative electrode current collector layer 54, and a solid electrolyte layer 56 having a solid electrolyte and disposed between the positive electrode layer and the negative electrode layer, wherein the exterior part has an ion conductivity of 10^-2S/cm or less.

According to the above configuration, the cathode active material layer 53 or the anode active material layer 55 in the charged state is configured to have the exterior part 51, thereby reducing the chance of exposure to components (mainly moisture) in the atmosphere. That is, generation of energy consumed in the reaction with components in the atmosphere can be suppressed.

In addition, by setting the ion conductivity to 10^-2The housing 51 having S/cm or less can reduce the deflection of lithium ions in the housing 51 during charging. This can suppress leakage current due to relaxation of the deflection of lithium ions in the exterior 51 in the open state after charging. By these, the self-discharge characteristics can be improved.

In the present embodiment, it is preferable that the ratio Y (ion conductivity of the exterior portion)/(ion conductivity of the solid electrolyte layer) between the ion conductivity of the exterior portion 51 and the ion conductivity of the solid electrolyte layer 56 of the all-solid battery 50 is Y ≦ 1.

According to the above configuration, when the ratio Y of the ion conductivity of the exterior portion 51 to the ion conductivity of the solid electrolyte layer 56 (ion conductivity of the exterior portion 51)/(ion conductivity of the solid electrolyte layer 56) is in this range, charging can be completed before the deflection of lithium ions in the exterior portion 51 at the time of charging becomes large. That is, the deflection of lithium ions in the exterior portion 51 can be reduced. This can further suppress leakage current due to relaxation of the deflection of lithium ions in the exterior portion 51 in the open state after charging, and can further improve the self-discharge characteristics.

In this embodiment modePreferably, the ratio Y (ion conductivity of exterior portion)/(ion conductivity of solid electrolyte layer) of the ion conductivity of exterior portion 51 to the ion conductivity of solid electrolyte layer 56 of all-solid battery 50 is 0. ltoreq. Y.ltoreq.1. Further, it is more preferable that the ratio Y of the ion conductivity of the exterior portion 51 to the ion conductivity of the solid electrolyte layer 56 is 10 ^-6Y is not less than 1. Further, it is more preferable that the ratio Y of the ion conductivity of the exterior portion 51 to the ion conductivity of the solid electrolyte layer 56 is 10^-6≤Y≤10^-2。

According to the above configuration, by configuring the all-solid-state battery such that the ratio of the ion conductivity of the exterior portion 51 to the ion conductivity of the solid electrolyte layer 56 constituting the power storage portion is within this range, it is possible to complete charging before the deflection of lithium ions in the exterior portion 51 becomes large, and it is possible to further reduce the deflection of lithium ions in the exterior portion 51. This makes it possible to further suppress leakage current due to relaxation of the deflection of lithium ions in the exterior part 51 in the open state after charging, and to further improve the self-discharge characteristics.

In the all-solid-state battery 50 according to the present embodiment, the exterior portion 51 is preferably configured as at least a part other than the power storage portion.

According to the above configuration, by providing the exterior portion 51 in at least a part of the all-solid battery 50 other than the power storage portion, the chance of exposure of the positive electrode active material layer 53 or the negative electrode active material layer 55 in the charged state to components (mainly moisture) in the atmosphere can be further reduced. In addition, the deflection of lithium ions in the exterior 51 during charging can be further reduced. By this, the self-discharge characteristics can be further improved.

In the all-solid battery 50 of the present embodiment, the exterior portion 51 is at least one or more selected from the group consisting of an oxide, an oxide of an alloy, a phosphate, a sulfide, a polyanion compound, and glass.

According to the above configuration, it is possible to suppress deviation of lithium ions in the exterior portion and to establish good bonding between the exterior portion 51 and the power storage unit. That is, by suppressing the occurrence of cracks due to poor bonding, and further reducing the chance that components in the atmosphere will enter from the cracks, and the positive electrode active material layer 53 or the negative electrode active material layer 55 will be exposed to components in the atmosphere (mainly moisture), the generation of energy consumed during the reaction with the components in the atmosphere can be suppressed. This can further improve the self-discharge characteristics.

In the present embodiment, the electron conductivity of the exterior portion 51 of the all-solid battery 50 is preferably 10^-9S/cm or less, more preferably 10^-11The following.

According to the above configuration, even in a state where the deviation of lithium ions in the exterior portion 51 is suppressed and a potential difference of an open circuit occurs during charge and discharge or after charge, the exterior portion 51 can be kept in an electrically good insulating state, and a short circuit between the exterior portion 51 and the power storage unit can be suppressed. This can further improve the self-discharge characteristics.

In the present embodiment, the porosity P of the exterior parts 51, 61 is preferably 0.4 or less, and more preferably 0.2 or less.

In the present specification, the "porosity" represents a ratio of a total area of the void portion to a total area of the exterior portion in an image of a cross section of the laminate parallel to the lamination direction. The porosity shown in the examples was calculated by the following method. A cross section of the laminate obtained by cutting the laminate parallel to the lamination direction by a cross section polisher (CP) was observed by a Scanning Electron Microscope (SEM). 10 sites were observed at 1000 times in a cross section including the exterior portion, and the porosity was calculated for each obtained SEM image using image processing software. The exterior portion in the SEM image is extracted by trimming, converted into a monochrome image and binarized (binarization), and the number of pixels is calculated by setting the void portion to black and the other portions to white. The extracted pixels of the exterior portion are calculated by adding the numbers of pixels of the void portion and the other portions. Then, the porosity P of the exterior part is calculated by the following equation.

Void ratio P of the exterior portion is defined as the number of pixels in the void portion/the number of pixels (void portion and other pixels)

(control of void fraction)

The method of controlling the porosity is not particularly limited, but can be controlled by the type or particle size of the sintering aid, the amount of addition thereof, the type or particle size of the sintering inhibitor, the amount of addition thereof, the type or particle size of the pore-forming material, the amount of addition thereof, the molding density of the molded article, the firing conditions (temperature rise rate or firing temperature, holding time, cooling rate, type or flow rate of gas), or a combination thereof.

According to the above configuration, by setting the porosity of the exterior parts 51, 61 within this range, it is possible to suppress deviation of lithium ions in the exterior parts 51, 61, and to establish a more favorable junction with the power storage element, and it is possible to suppress intrusion of components in the atmosphere from cracks due to poor junction, and to reduce leakage current. This can further improve the self-discharge characteristics.

In the present embodiment, the all-solid battery 50 preferably has a relative density of 80% or more, more preferably 90% or more, of a positive electrode layer including the positive electrode current collector layer 52 and the positive electrode active material layer 53 provided on the positive electrode current collector layer 52, a negative electrode layer including the negative electrode current collector layer 54 and the negative electrode active material layer 55 provided on the negative electrode current collector layer 54, a power storage unit including the solid electrolyte layer 56 having a solid electrolyte interposed therebetween, and the exterior unit 51.

According to the above configuration, by providing the all-solid-state battery 50 having the relative density in this range, the all-solid-state battery 50 having improved self-discharge characteristics and a long cycle life can be obtained.

The composition of the positive electrode collector layer 52 and the negative electrode collector layer 54 is not particularly limited, but for example, a positive electrode active material or a negative electrode active material, a solid electrolyte, and a sintering aid may be contained at an arbitrary ratio in addition to the collector material.

The composition of the positive electrode active material layer 53 and the negative electrode active material layer 55 is not particularly limited, but for example, a lithium ion conduction auxiliary agent, a sintering auxiliary agent, or a conduction auxiliary agent may be contained in the positive electrode active material or the negative electrode active material.

The composition of the solid electrolyte layer 56 is not particularly limited, but for example, a sintering aid may be contained in addition to the solid electrolyte.

The positive electrode active material and the negative electrode active material constituting the positive electrode active material layer 53 and the negative electrode active material layer 55 have a potential of each of the compounds compared with each other. Specifically, among the respective compounds, a compound having a higher potential can be used as the positive electrode active material, and a compound having a lower potential can be used as the negative electrode active material. The positive electrode active material layer 53 and the negative electrode active material layer 55 may be formed of a single compound or a plurality of compounds.

(solid electrolyte)

As the solid electrolyte constituting the solid electrolyte layers 56, 66, 15 of the all-solid-state battery according to the present embodiment, a material having low electron conductivity and high lithium ion conductivity is preferably used. Although not limited to these examples, for example, it is preferably selected from La_0.5Li_0.5TiO₃Perovskite-type compound of (i) and (ii), Li₁₄Zn(GeO₄)₄LISICON-type compounds of the same type, Li₇La₃Zr₂O₁₂Etc. garnet-type compound, LiTi₂(PO₄)₃Or LiGe₂(PO₄)₃、LiZr₂(PO₄)₃(monoclinic) LiZr₂(PO₄)₃(rhombohedral), Li_1.5Ca_0.5Zr_1.5(PO₄)₃、Li_1.3Al_0.3Ti_1.7(PO₄)₃Or Li_1.5Al_0.5Ge_1.5(PO₄)₃、Li₃PO₄Or Li_3.5Si_0.5P_0.5O₄、Li_2.9PO_3.3N_0.46Phosphorus oxide compounds of the like, Li_3.25Ge_0.25P_0.75S₄、Li₃PS₄iso-Thio-lithium super ion conductor (Li-sulfide crystal lithium super ion conductor) type compound, Li₂S-P₂S₅、Li₂O-V₂O₅-SiO₂And the like.

From the viewpoint of forming a dense layer in a thin manner, the particle size of the solid electrolyte constituting the solid electrolyte layer of the all-solid battery according to the present embodiment is preferably 0.05 μm to 5 μm, and more preferably 0.1 μm to 2.5 μm.

The thickness of the solid electrolyte layers 56, 66, 16 is not particularly limited, but is preferably 0.1 to 100 μm, more preferably 0.3 to 20 μm, and still more preferably 0.6 to 10 μm, from the viewpoint of maintaining the self-discharge characteristics and realizing the high rate characteristics.

By setting the thickness of the solid electrolyte layers 56, 66, and 16 in this range, the distance of movement of lithium ions during charge and discharge can be shortened while the insulation properties of the solid electrolyte layers 56, 66, and 16 are maintained, and the internal resistance can be reduced.

(Positive electrode active Material)

The positive electrode active material contained in the positive electrode active material layers 53, 63, 12 and the positive electrode current collector layers 52, 62, 11 according to the present embodiment is preferably a lithium-containing compound such as a lithium oxide, a lithium sulfide, or an interlayer compound containing lithium, for example, and 2 or more of these may be mixed and used. Particularly from the viewpoint of improving energy density, it is preferable to use a compound represented by the general formula Li_xMO₂The lithium composite oxide or lithium-containing interlayer compound shown is used as the positive electrode active material layers 53, 63, 12. M is preferably at least one transition metal, and more specifically, is preferably at least one of Co, Ni, Mn, Fe, Al, V, and Ti. x varies depending on the charge/discharge state of the battery, and is usually in the range of 0.05. ltoreq. x.ltoreq.1.10. In addition, manganese spinel (LiMn) having a spinel-type crystal structure is used₂O₄) Lithium iron phosphate (LiFePO) having an olivine-type crystal structure₄) Or LiCoPO₄、LiNiPO₄And the like, and a high energy density can be obtained, and is therefore preferable.

Specifically, as the positive electrode active material constituting the positive electrode active material layers 53, 63, and 12 of the all-solid-state batteries 50 and 60 and the power storage unit 10, a material that efficiently releases and adsorbs lithium ions is preferably used. For example, a transition metal oxide or a transition metal composite oxide is preferably used. Specifically, it is preferable to use a lithium manganese composite oxide Li ₂Mn_x3Ma_1-x3O₃(0.8. ltoreq. x 3. ltoreq.1, Ma. Co, Ni), lithium cobaltate (LiCoO)₂) Lithium nickelate (LiNiO)₂) Lithium manganese spinel (LiMn)₂O₄) And by the general formula: LiNi_x4Co_y4Mn_z4O₂(x4+ y4+ z4 ═ 1, 0. ltoreq. x 4. ltoreq.1, 0. ltoreq. y 4. ltoreq.1, 0. ltoreq. z 4. ltoreq.1), and a lithium vanadium compound (LiV)₂O₅) Olivine type LiMbPO₄(where Mb is at least one element selected from the group consisting of Co, Ni, Mn, Fe, Mg, Nb, Ti, Al and Zr), and lithium vanadium phosphate (Li)₃V₂(PO₄)₃Or LiVOPO₄) Li-excess solid solution positive electrode Li₂MnO₃-LiMcO₂(Mc ═ Mn, Co, Ni), lithium titanate (Li)₄Ti₅O₁₂) With LiaNi_x5Co_y5Al_z5O₂(0.9 < a < 1.3, 0.9 < x5+ y5+ z5 < 1.1). The positive electrode active material constituting the positive electrode active material layers 53, 63, and 12 is not limited to these materials, and any material may be used as long as it is a positive electrode active material that electrochemically intercalates and deintercalates lithium ions.

From the viewpoint of forming the positive electrode active material layer densely and thinly, the particle diameter of the positive electrode active material constituting the positive electrode active material layers 53, 63, and 12 of the present embodiment is preferably 0.05 μm or more and 5 μm or less, and more preferably 1 μm or more and 2.5 μm or less.

The thickness of the positive electrode active material layers 53, 63, 12 is not particularly limited, but is preferably 0.1 to 100 μm, more preferably 0.3 to 10 μm, and still more preferably 0.6 to 5 μm, from the viewpoint of obtaining an all-solid-state battery having improved self-discharge characteristics, high capacity, and high output.

(negative electrode active Material)

As the negative electrode active material contained in the negative electrode active material layers 55, 65, and 14 of the present embodiment, a material having a low potential with respect to lithium and a large capacity per unit weight is preferably used from the viewpoint of obtaining an all-solid-state battery having a high weight energy density and a high volume energy density. For example, at least one metal selected from the group consisting of Li, Sn, Si, Al, Ge, Sb, Ag, Ga, In, Fe, Co, Ni, Ti, Mn, Ca, Ba, La, Zr, Ce, Cu, Mg, Sr, Cr, Mo, Nb, V, and Zn, an alloy composed of 2 or more of these metals, an oxide or a phosphate of the above metal, and at least one of an oxide or a phosphate of the above alloy, or a substance containing a carbon material is preferable.

From the viewpoint of forming the negative electrode active material layer densely and thinly, the particle diameter of the negative electrode active material constituting the negative electrode active material layers 55, 65, and 14 of the present embodiment is preferably 0.05 μm or more and 5 μm or less, and more preferably 0.1 μm or more and 2.5 μm or less.

The thickness of the negative electrode active material layers 55, 65, 14 is not particularly limited, but is preferably 0.1 to 100 μm, more preferably 0.5 to 10 μm, and still more preferably 1 to 5 μm, from the viewpoint of obtaining an all-solid-state battery having improved self-discharge characteristics, higher capacity, and longer cycle life.

(outer cover Material)

As the exterior material constituting the exterior 51, 61 of the all-solid battery according to the present embodiment, it is preferable to use an exterior material having a small electron conductivity and a lithium ion conductivity equal to or less than the lithium ion conductivity of the solid electrolyte constituting the solid electrolyte layers 56, 66, 15. The polymer is not limited to these examples, but is preferably selected from La_0.5Li_0.5TiO₃Perovskite-type compound of (i) and (ii), Li₁₄Zn(GeO₄)₄LISICON-type compounds of the same type, Li₇La₃Zr₂O₁₂Etc. garnet-type compound, LiTi₂(PO₄)₃Or LiGe₂(PO₄)₃、LiZr₂(PO₄)₃(monoclinic) LiZr₂(PO₄)₃(rhombohedral), Li_1.5Ca_0.5Zr_1.5(PO₄)₃、Li_1.3Al_0.3Ti_1.7(PO₄)₃Or Li_1.5Al_0.5Ge_1.5(PO₄)₃、Li₃PO₄Or Li_3.5Si_0.5P_0.5O₄Or Li_2.9PO_3.3N_0.46Phosphorus oxide compounds of the like, Li_3.25Ge_0.25P_0.75S₄Or Li₃PS₄Iso Thio-LISICON type compounds, Li₂S-P₂S₅Or Li₂O-V₂O₅-SiO₂Glass compound such as boric acid glass, silicic acid glass, borosilicate glass, or the like, ZrO₂、Al₂O₃、SiO₂And the like.

From the viewpoint of forming a dense layer, the particle diameter of the exterior material constituting the exterior of the all-solid battery of the present embodiment is preferably 0.05 μm or more and 5 μm or less, and more preferably 0.1 μm or more and 2.5 μm or less.

The thickness of the exterior parts 51, 61 of the all-solid battery according to the present embodiment is not particularly limited, but is preferably 0.1 to 1000 μm, and more preferably 1 to 500 μm, from the viewpoint of obtaining an all-solid battery in which the self-discharge characteristics are improved while suppressing the intrusion of air, and the cycle life is longer.

(conductive auxiliary agent)

The positive electrode active material layers 53, 63, and 12 and the negative electrode active material layers 55, 65, and 14 of the present embodiment may be added with a conductive assistant. By adding a conductive aid to the positive electrode active material layers 53, 63, 12 and the negative electrode active material layers 55, 65, 14, the conductivity can be improved. The conductive aid used in the present embodiment is not particularly limited, and a known material can be used. The conductive auxiliary agents added to the positive electrode active material layer and the negative electrode active material layer may be the same or different.

When a conductive aid is used for the positive electrode active material layers 53, 63, 12 and the negative electrode active material layers 55, 65, 14, it is preferable to use a conductive aid having high conductivity. For example, silver, palladium, silver-palladium alloy, gold, platinum, aluminum, copper, nickel, carbon, or the like is preferably used.

The particle diameter of the conductive assistant is preferably 0.02 μm or more and 2 μm or less, and more preferably 0.05 μm or more and 1 μm or less, from the viewpoint of improving electron connection between the positive electrode active material and the positive electrode current collector layer or between the negative electrode active material and the negative electrode current collector layer.

The ratio of the conductive auxiliary agent to be added is not particularly limited as long as the positive electrode active material or the negative electrode active material contained in the positive electrode active material layers 53, 63, and 12 and the negative electrode active material layers 55, 65, and 14 electrochemically functions. The ratio of the positive electrode active material/the conductive additive or the negative electrode active material/the conductive additive is preferably in the range of 100/0 to 60/40, more preferably in the range of 85/15 to 75/25, in terms of volume ratio. By setting the ratio of the conductive additive to this range, an all-solid-state battery having improved self-discharge characteristics, higher capacity, and high output can be obtained, and the resistance can be reduced.

(lithium ion conducting assistant)

The positive electrode active material layers 53, 63, and 12 and the negative electrode active material layers 55, 65, and 14 of the present embodiment may be added with a lithium ion conductive auxiliary agent. With this structure, lithium ion conductivity can be improved. The lithium ion conduction auxiliary agent used in the present embodiment is not particularly limited, and a known material can be used. The lithium ion conductive auxiliary agents added to the positive electrode active material layer and the negative electrode active material layer may be the same or different.

The lithium ion conduction aid is preferably a material having high lithium ion conductivity. The polymer is not limited to these examples, but is preferably selected from La_0.5Li_0.5TiO₃Perovskite type compounds of the like or Li₁₄Zn(GeO₄)₄LISICON-type compounds of the same type, Li₇La₃Zr₂O₁₂Etc. garnet-type compound, LiTi₂(PO₄)₃、LiGe₂(PO₄)₃、LiZr₂(PO₄)₃(monoclinic) LiZr₂(PO₄)₃(rhombohedral), Li_1.5Ca_0.5Zr_1.5(PO₄)₃、Li_1.3Al_0.3Ti_1.7(PO₄)₃、Li_1.5Al_0.5Ge_1.5(PO₄)₃、Li₃PO₄Or Li_3.5Si_0.5P_0.5O₄Or Li_2.9PO_3.3N_0.46Phosphorus-oxygen compounds of lithium phosphate and the like, Li_3.25Ge_0.25P_0.75S₄Or Li₃PS₄And the like Thio-LISICON type compounds, LiPON, lithium niobate, lithium silicate, lithium borate, and the like oxides, Li₂S-P₂S₅Or Li₂O-V₂O₅-SiO₂And the like.

From the viewpoint of improving the movement of lithium ions between the positive electrode active material layers 53, 63, 12 and the solid electrolyte layers 56, 66, 15 or between the negative electrode active material layers 55, 65, 14 and the solid electrolyte layers 56, 66, 15, the particle size of the lithium ion conduction aid is preferably 0.02 μm or more and 2 μm or less, more preferably 0.05 μm or more and 1 μm or less, and still more preferably 0.1 μm or more and 0.5 μm or less.

The ratio of the lithium ion conductive additive to be added is not particularly limited as long as the positive electrode active material or the negative electrode active material contained in each of the positive electrode active material layers 53, 63, 12 or the negative electrode active material layers 55, 65, 14 electrochemically functions. For example, in order to obtain an all-solid-state battery having improved self-discharge characteristics, higher capacity, and higher output, the ratio of the positive electrode active material/the lithium ion conduction aid, or the negative electrode active material/the lithium ion conduction aid is preferably in the range of 100/0 to 60/40 in terms of volume ratio, and more preferably in the range of 85/15 to 75/25, from the viewpoint of reducing internal resistance.

(Current collector Material)

Specific examples of the collector material constituting the positive electrode collector layers 52, 62, 12 and the negative electrode collector layers 54, 64, 13 are preferably gold (Au), platinum (Pt) -palladium (Pd), silver (Ag) -palladium (Pd), aluminum (Al), copper (Cu), nickel (Ni), an indium-tin oxide film (ITO), or the like.

The positive electrode current collector layers 52, 62, 11 and the negative electrode current collector layers 54, 64, 13 may contain a positive electrode active material and a negative electrode active material, respectively. The content ratio of the active material contained in each current collector is not particularly limited as long as the active material functions as a current collector. For example, the volume ratio of the positive electrode current collector material/the positive electrode active material or the negative electrode current collector material/the negative electrode active material is preferably 95/5 to 70/30, and more preferably 90/10 to 75/25.

It is preferable that the positive electrode collector layers 52, 62, 11 and the negative electrode collector layers 54, 64, 13 contain the positive electrode active material and the negative electrode active material, respectively, in that the adhesion between the positive electrode collector layers 52, 62, 11 and the positive electrode active material layer and between the negative electrode collector layers 54, 64, 13 and the negative electrode active material layer is improved and cracks are suppressed.

(sintering aid)

The type of sintering aid added to the exterior 51, 61, the positive electrode current collector layer 52, 62, the positive electrode active material layer 53, 63, the negative electrode current collector layer 54, 64, the negative electrode active material layer 55, 65, and the solid electrolyte layer 56, 66 constituting the all-solid-state battery 50, 60 is not particularly limited as long as the sintering temperature can be lowered. The lithium compound is not limited to these examples, but for example, lithium compounds such as lithium carbonate, lithium hydroxide and lithium phosphate, or H₃BO₃And the like, and compounds composed of lithium and boron. The compound form of these materials is not easily changed by water or carbon dioxide, and therefore, it is preferable because it can be weighed in the air and lithium and boron can be added easily and accurately.

(pore-forming Material)

The type of the pore forming material added to the exterior parts 51, 61, the positive electrode active material layers 53, 63, the negative electrode active material layers 55, 65, and the solid electrolyte layers 56, 66 constituting the all-solid batteries 50, 60 is not particularly limited as long as a void can be introduced. The material is not limited to these examples, but for example, a material that decomposes/sublimates by heat at the time of firing, a water-soluble material, and the like are included. The water-soluble material may be any material as long as it is soluble in water and washable with water, such as sucrose, glucose, fructose, and other sugars, or a water-soluble polymer such as carboxymethyl cellulose or alginic acid. These materials can be weighed in air and easily handled, and therefore, can be accurately added, and are preferred.

(terminal electrode)

The terminal electrodes 57 and 67 of the all-solid batteries 50 and 60 are preferably made of a material having high electrical conductivity. For example, silver, gold, platinum, aluminum, copper, tin, and nickel can be used. The terminal electrodes 57 and 67 may be a single layer or a plurality of layers.

(method for manufacturing all-solid-state Battery)

The all-solid batteries 50 and 60 can be manufactured by, for example, a simultaneous firing method or a sequential firing method. The simultaneous firing method is a method of manufacturing a laminate by stacking materials forming each layer and firing the layers together. The sequential firing method is a method of sequentially producing each layer, and a firing step is performed for each production of each layer. The simultaneous firing method can relatively reduce the number of steps for operating the all-solid batteries 50 and 60. The following describes a method for manufacturing the all-solid batteries 50 and 60 by taking a case of using the simultaneous firing method as an example. As described above, the method for manufacturing the all-solid batteries 50 and 60 is not limited to the simultaneous firing method, and may be manufactured by a sequential firing method.

First, the materials constituting the exterior parts 51, 61, the positive electrode collector layers 52, 62, the positive electrode active material layers 53, 63, the solid electrolyte layers 56, 66, the negative electrode collector layers 54, 64, and the negative electrode active material layers 55, 65 of the all-solid-state batteries 50, 60 are formed into a paste.

The method for pasting is not particularly limited. For example, the paste is obtained by mixing powders of the respective materials in a solvent. Here, the solvent is a generic term for a liquid-phase medium. The solvent generally contains a solvent, a dispersant and a binder. By the above-described method, the paste for the exterior part, the paste for the positive electrode collector layer, the paste for the positive electrode active material layer, the paste for the solid electrolyte layer, the paste for the negative electrode collector layer, and the paste for the negative electrode active material layer were prepared.

The composition of the paste for the positive electrode collector layer and the paste for the negative electrode collector layer is not particularly limited, but for example, a positive electrode active material or a negative electrode active material, a solid electrolyte, and a sintering aid may be contained in addition to the collector material.

The composition of the positive electrode active material layer paste and the negative electrode active material layer paste is not particularly limited, but for example, a solid electrolyte, a sintering aid, a conductive aid, a lithium ion conductive aid, and a pore-forming material may be contained in addition to the positive electrode active material or the negative electrode active material.

The composition of the paste for the solid electrolyte layer is not particularly limited, but for example, a sintering aid or a pore-forming material may be contained in addition to the solid electrolyte.

The composition of the paste for the exterior portion is not particularly limited, but for example, a sintering aid or a pore-forming material may be contained in addition to the exterior portion material.

The prepared paste for an exterior part and the paste for a solid electrolyte layer were applied to a substrate such as PET (polyethylene terephthalate) in a desired order, and dried as necessary to obtain a green sheet for an exterior part and a green sheet for a solid electrolyte layer. The method of applying the paste is not particularly limited, and known methods such as screen printing, coating, transfer, and doctor blade can be used.

On the prepared green sheet for the solid electrolyte layer or the green sheet for the exterior portion, a positive electrode active material layer paste and a positive electrode current collector layer paste were screen-printed in a predetermined order to form a positive electrode active material layer and a positive electrode current collector layer, and a green sheet for a positive electrode layer was prepared. In addition, depending on the case, the positive electrode active material layer and the positive electrode current collector layer to be printed may be replaced with a screen having an unprinted pattern, and the paste for the exterior portion may be printed on the unprinted portion of the positive electrode layer green sheet.

Similarly, on the produced green sheet for the solid electrolyte layer or the green sheet for the exterior portion, a paste for the negative electrode active material layer and a paste for the negative electrode current collector layer were screen-printed in a predetermined order to form the negative electrode active material layer and the negative electrode current collector layer, and a green sheet for the negative electrode layer was produced. In addition, the negative electrode active material layer and the negative electrode current collector layer may be printed using a screen having an unprinted pattern, and the paste for the exterior portion may be printed on the unprinted portion of the negative electrode layer green sheet.

After the green sheets for exterior parts are laminated in a desired number, the produced green sheets for positive electrode layers and the green sheets for negative electrode layers are laminated in a desired order in a staggered manner such that the positive electrode current collector layer of the green sheet for positive electrode layers extends only to one end face and the negative electrode current collector layer of the green sheet for negative electrode layers extends only to the other face, and then the green sheets for exterior parts are laminated again in a desired number to obtain a pre-laminated body.

In the case of producing a parallel or series-parallel all-solid-state battery, it is preferable to stack the positive electrode active material layers in alignment so that the end faces of the positive electrode active material layers do not coincide with the end faces of the negative electrode active material layers. The laminated structure is not limited to this.

The prepared prelaminates were collectively pressure-bonded to prepare a laminate. The crimping is performed while heating, but the heating temperature is set to 40 to 90 ℃, for example.

The obtained laminate is aligned and cut as necessary to produce a laminate singulated into desired dimensions. The cutting method is not limited, but cutting may be performed by cutting, knife cutting, or the like.

Before firing the singulated laminate, chamfering may be performed by dry or wet green roll polishing.

In the dry barrel polishing, the polishing may be performed together with a polishing agent such as alumina, zirconia, or resin beads.

In wet barrel polishing, a solvent is used in addition to a polishing agent such as alumina, zirconia, or resin beads. In this case, for example, ion-exchanged water, purified water, fluorine-based solvents, and the like can be used as the solvent.

When a water-soluble pore-forming material is used, ion-exchanged water or purified water may be used for wet barrel polishing, so that the water can be washed together with the water.

When dry barrel polishing is performed without wet barrel polishing, the water-soluble pore-forming material can be removed by washing with ion-exchanged water or purified water.

The monolithic laminate is heated and fired in a nitrogen atmosphere, for example, to obtain a sintered body. In the production of the all-solid-state batteries 50 and 60 according to the present embodiment, the firing temperature is preferably set to a range of 600 to 1200 ℃. This is because when the temperature is lower than 600 ℃, firing does not sufficiently proceed, and when the temperature exceeds 1200 ℃, problems such as dissolution of the current collector material, structural changes of the positive electrode active material and the negative electrode active material occur. Further, it is more preferable to set the temperature to 700 to 1000 ℃. Setting the temperature to 700 to 1000 ℃ is more suitable for accelerating firing and reducing manufacturing cost. The firing time is, for example, 10 minutes to 3 hours.

The obtained sintered body may be put in a cylindrical container together with an abrasive such as alumina or resin beads and barrel-polished. This enables chamfering of the corners of the sintered body. As another method, the polishing may be performed by sandblasting. This method is preferable because only a specific portion can be cut.

When the terminal electrodes 57 and 67 are not formed before firing, the terminal electrodes 57 and 67 can be formed by applying a known method such as sputtering, dipping, or spraying to the obtained sintered body. When the film is formed only in a predetermined portion, the film can be formed by, for example, masking with a tape.

The method of forming the terminal electrodes 57 and 67 is not limited, but specific examples of materials that can be used for the terminal electrodes 57 and 67 include: gold (Au), platinum (Pt) -palladium (Pd), silver (Ag) -palladium (Pd), aluminum (Al), copper (Cu), indium-tin oxide film (ITO), and the like.

In the method of forming the terminal electrodes 57 and 67, the terminal electrodes may be formed by thermosetting conductive paste obtained by mixing and pasting the particles of the conductive material with thermosetting resin.

The terminal electrodes 57 and 67 may be plated. The plating method and the type of the coating are not particularly limited, and for example, a Ni coating may be formed by electroless Ni plating or electrolytic Ni plating, and then a Sn coating may be formed by electrolytic tin plating to form a Ni — Sn coating.

Further, a film of at least one metal such as Pt, Au, Cu, Ti, Ni, and Sn, or an alloy thereof may be formed on the terminal electrodes 57 and 67 by sputtering.

The surfaces of the all-solid batteries 50 and 60 according to the present embodiment may be subjected to water repellent treatment. The method of the water repellent treatment is not particularly limited, but for example, the water repellent treatment can be formed by immersing the substrate in a solution made of a fluororesin, a silane resin, or the like.

A glass layer may be formed on the surface of the all-solid batteries 50 and 60 according to the present embodiment. The forming method is not particularly limited, and the glass can be formed by coating a low-melting glass and performing heat treatment at a desired temperature.

The all-solid-state batteries 50 and 60 of the present embodiment may be housed in a case having high sealing properties. The shape of the housing to be housed is not particularly limited, and a known shape can be adopted. For example, the shape may be a square, a cylinder, a button, or a card.

The all-solid batteries 50 and 60 of the present embodiment may be coated with resin. The resin that can be used is a known resin, but from the viewpoint of improving the heat resistance and moisture resistance of the coating film, a fluorine-based resin, an imide-based resin, and an epoxy resin are preferably used.

The all-solid-state batteries 50 and 60 of the present embodiment may be used in combination with other lithium ion secondary batteries, solar power generation units, wind power generation units, geothermal power generation units, piezoelectric elements, thermoelectric elements, and the like.

While the embodiments of the present invention have been described in detail with reference to the drawings, the configurations and combinations thereof of the embodiments are merely examples, and additions, omissions, substitutions, and other modifications of the configurations can be made without departing from the spirit of the present invention. The plurality of embodiments may be appropriately combined and implemented within a range in which the effects thereof are achieved.