JP4381176B2 - Thin film solid secondary battery - Google Patents

Description

  The present invention relates to a thin film solid secondary battery, and more particularly to a thin film solid secondary battery that can be reduced in thickness and size.

Currently, lithium ion secondary batteries are widely used mainly in electronic devices such as portable devices. This is because the lithium ion secondary battery has a high voltage, a large charge / discharge capacity, and no adverse effects such as a memory effect as compared with a nickel cadmium battery or the like.
Electronic devices and the like have been increasingly reduced in size and weight, and lithium-ion secondary batteries are also being developed to be further reduced in size and weight as batteries to be mounted on these electronic devices and the like. In recent years, development of a thin and small lithium ion secondary battery that can be mounted on an IC card, a small medical device, or the like is also in progress. It is expected that further reduction in thickness and size will be required in the future.

A conventional lithium ion secondary battery uses a metal piece or a metal foil for a positive electrode and a negative electrode, is immersed in an electrolytic solution and covered with a container. For this reason, there is a limit to thinning and miniaturization. Actually, it is considered that the limit is about 1 mm in thickness and about 1 cm ³ in volume.
However, recently, in order to enable further reduction in thickness and size, a polymer battery using a gel electrolyte instead of an electrolytic solution (for example, see Patent Document 1) or a thin film solid secondary battery using a solid electrolyte (for example, Patent Document 2) has been developed.
The polymer battery described in Patent Document 1 has a positive electrode current collector inside an exterior body, a composite positive electrode containing a polymer solid electrolyte inside, an electrolyte layer made of an ion conductive polymer compound, and a polymer solid electrolyte inside. The composite negative electrode and the negative electrode current collector are sequentially arranged.
Although the polymer battery can be made thinner and smaller than a normal lithium ion secondary battery using an electrolytic solution, it requires a gel electrolyte, a bonding agent, a sealing member, etc. About 1 mm is the limit, and is not suitable for further thinning and miniaturization.

On the other hand, as described in Patent Document 2, the thin film solid secondary battery has a structure in which a current collector thin film, a negative electrode active material thin film, a solid electrolyte thin film, a positive electrode active material thin film, and a current collector thin film are sequentially laminated on a substrate. A configuration or a configuration in which the above layers are stacked in the reverse order on a substrate.
With such a configuration, the thin-film solid secondary battery can be made as thin as about 1 μm except for the substrate. Further, if the thickness of the substrate is reduced or a thin solid electrolyte film is used instead of the substrate, the overall thickness can be reduced and the size can be reduced.

Japanese Patent Laid-Open No. 10-74496 (page 3-6, FIG. 1-2) JP-A-10-284130 (page 3-4, FIG. 1-4)

As described above, thin-film solid-state secondary batteries are expected to be thinner and smaller. However, in order to actually use the thin-film secondary batteries, the negative electrode active material thin film and the positive electrode active material thin film having high electric resistance have an electric resistance. It is necessary to stack a current collector thin film such as a low metal.
For this reason, the process of laminating | stacking a collector thin film is necessarily required, and there existed a problem that manufacturing time and manufacturing cost would be extra.

  Further, a vanadium oxide thin film or a niobium oxide thin film is generally used for the negative electrode active material thin film of the thin film solid secondary battery in order to improve battery performance. However, since these substances are vulnerable to moisture, it is necessary to cover a portion where the thin film solid secondary battery is exposed to the atmosphere with a moisture prevention thin film such as silicon nitride. Furthermore, vanadium oxide has a problem that it is toxic. For this reason, there was a problem that manufacturing time and manufacturing cost were excessive.

  An object of the present invention is to provide a thin-film solid secondary battery having a simple structure and high battery performance using a safe substance.

Anode active object is achieved, according to the thin-film solid secondary battery of the present invention, which on a substrate, comprising: a positive electrode collector layer, a positive electrode active material layer, a solid electrolyte layer, the function of the anode current collector layer an oxide conductive film layer serving as a material layer, but are stacked in this order, the oxide conductive film layer, the resistivity is characterized by comprising the following materials 1 × 10 ^-2 Ω · cm.
In the present invention, the oxide conductive film layer can also serve as the negative electrode active material layer and the negative electrode current collector layer on the negative electrode side. In order for the current collector layer to function well as an extraction electrode, the current collector layer preferably has a sheet resistance of about 1 kΩ / □ or less. Therefore, in the case of a thin film solid secondary battery, if the thickness of the current collector layer is set to about 0.1 μm or more, the resistivity of the substance used for the current collector layer is about 1 × 10 ⁻² Ω · cm or less. There must be.
On the other hand, in a conventional thin film solid secondary battery, a negative electrode active material layer and a negative electrode current collector layer are laminated on the negative electrode side. The vanadium pentoxide and niobium pentoxide used in this negative electrode active material layer have a resistivity on the order of 10 ⁵ Ω · cm. These substances have a very high resistance value as described above, are hardly conductive, and are close to insulators. Therefore, conventionally, the negative electrode active material layer could not serve as the current collector layer.
However, in the present invention, a material having a resistivity of 1 × 10 ⁻² Ω · cm or less is used for the oxide conductive film layer functioning as the negative electrode active material layer. Therefore, the oxide conductive film layer of the present invention has low resistance and can function as a negative electrode current collector layer. For this reason, in this invention, it is not necessary to provide a negative electrode collector layer separately, and it is possible to reduce manufacturing time and manufacturing cost.
In addition, since the negative electrode active material layer is not separately provided, it is preferable that a toxic substance such as harmful vanadium pentoxide is not used.

Further, an oxide conductive film layer functioning as a negative electrode active material layer having a function of a negative electrode current collector layer , a solid electrolyte layer , a positive electrode active material layer, and a positive electrode current collector layer are formed on the substrate. The oxide conductive film layers may be sequentially stacked, and the oxide conductive film layer may have a resistivity of 1 × 10 ⁻² Ω · cm or less.

In addition, an oxide conductive film layer functioning as a negative electrode active material layer having a function of a negative electrode current collector layer is formed on one surface of the solid electrolyte film, and a positive electrode active material layer and a positive electrode current collector are formed on the other surface. The layers may be stacked in this order, and the oxide conductive film layer may be formed of a material having a resistivity of 1 × 10 ⁻² Ω · cm or less.
The thin film solid secondary battery formed as described above may be stacked so that the positive electrode current collector layer and the oxide conductive film layer are in contact with each other.
Moreover, you may comprise a thin film solid secondary battery so that the said positive electrode collector layer and the said oxide electrically conductive film layers may contact.

Also, on a substrate, a positive electrode collector layer, a positive electrode active material layer, a solid electrolyte layer, and the oxide conductive layer functioning as an anode active material layer having a function of a negative electrode collector layer, but this A thin-film solid secondary battery in which a plurality of secondary battery cells stacked in order are stacked, and the secondary battery cell is stacked so that the positive electrode current collector layer and the oxide conductive film layer are in contact with each other. The oxide conductive film layer may be made of a material having a resistivity of 1 × 10 ⁻² Ω · cm or less.
In addition, a thin film solid secondary battery may be configured by stacking a plurality of the secondary battery cells such that the positive electrode current collector layers and the oxide conductive film layers are in contact with each other.

And the substance which forms the said oxide electrically conductive film layer can select any of indium oxide, tin oxide, zinc oxide, or the thing which has either of these as a main component. By using the oxide conductive film layer as the above substance, a moisture prevention effect can be obtained. Thereby, battery characteristics can be maintained without providing a moisture prevention film separately. Therefore, in the thin film solid secondary battery of the present invention, the manufacturing process can be omitted, and the manufacturing cost can be reduced.
Further, the positive electrode active material layer can be an active material layer having a metal oxide containing lithium as a constituent element. Further, it is preferable that a moisture prevention film is further laminated on the surface.
The current collector layer, the positive electrode active material layer, the solid electrolyte layer, and the oxide conductive film layer are preferably formed by a sputtering method.

The present invention has the following effects.
(1) Since the first effect of the present invention is a simpler structure than the conventional thin film solid state secondary battery, the battery characteristics such as the charge / discharge capacity, the discharge start voltage, and the cycle characteristics can be obtained with less production time and process. Can produce a thin-film solid-state secondary battery excellent in.
(2) The second effect of the present invention eliminates the use of a toxic substance such as vanadium pentoxide which is harmful as a negative electrode active material. Thereby, it can be produced without taking time and effort.
(3) According to the third effect of the present invention, since the oxide conductive film having the effect of preventing moisture is used, the battery characteristics are hardly deteriorated by moisture.
(4) According to the fourth effect of the present invention, it is possible to further suppress the deterioration of performance by covering the surface exposed to the atmosphere with a moisture preventing film having a moisture preventing effect.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The members, arrangements, configurations, and the like described below do not limit the present invention and can be variously modified within the scope of the gist of the present invention.
1 to 3 relate to an embodiment of the present invention, and FIGS. 1, 2 and 3 are sectional views of thin film solid state secondary batteries according to Embodiments 1, 2 and 3, respectively. 4 to 6 relate to a comparative example, and FIGS. 4, 5, and 6 are cross-sectional views of thin-film solid state secondary batteries according to comparative examples 1, 2, and 3, respectively. FIG. 7 is a graph of charge / discharge characteristics of the thin-film solid secondary battery of the example. 8 to 11 are sectional views of the thin film solid state secondary batteries according to Examples 7 to 10, respectively.

1 to 3 are cross-sectional views showing the configuration of the thin-film solid secondary battery 1 of the present invention.
In the embodiment of FIG. 1, in the thin film solid secondary battery 1, a current collector layer 20 on the positive electrode side, a positive electrode active material layer 30, a solid electrolyte layer 40, and an oxide conductive film layer 50 are sequentially stacked on a substrate 10. Is formed.
In the embodiment of FIG. 2, the thin film solid secondary battery 1 includes an oxide conductive film layer 50, a solid electrolyte layer 40, a positive electrode active material layer 30, and a current collector layer 20 on the positive electrode side in order on a substrate 10. It is formed by stacking. In the configuration of FIG. 2, the order of stacking on the substrate 10 is opposite to that of FIG.
In the embodiment of FIG. 3, the positive electrode active material layer 30 and the positive electrode current collector layer 20 are sequentially laminated on one surface of the solid electrolyte film 60, and the oxide conductive film layer 50 is formed on the other surface. It is formed by stacking.
In the thin-film solid secondary battery 1 of the present embodiment shown in FIGS. 1 to 3, the oxide conductive film layer 50 of the negative electrode side has both the function of the negative electrode current collector layer, the oxide conductive film layer 50 A separate negative electrode current collector layer is not provided on the surface.

As the substrate 10, glass, semiconductor silicon, ceramic, stainless steel, a resin substrate, or the like can be used. As the resin substrate, polyimide, PET, or the like can be used. In addition, a thin film that can be bent can be used for the substrate 10 as long as it can be handled without losing its shape.
The current collector layer 20 can be a metal thin film having good adhesion to the positive electrode (positive electrode active material layer 30) and the solid electrolyte layer 40 and having low electrical resistance. In order for the current collector layer 20 to function satisfactorily as an extraction electrode, the sheet resistance is desirably 1 kΩ / □ or less. When the film thickness of the current collector layer 20 is set to about 0.1 μm or more, the current collector layer 20 needs to be formed of a material having a resistivity of about 1 × 10 ⁻² Ω · cm or less. As such a substance, for example, vanadium, aluminum, copper, nickel, gold or the like can be used. With these materials, the current collector layer 20 can be formed to a thickness of about 0.3 μm that is as thin as possible and has a low electrical resistance.
Table 1 shows the resistance values and sheet resistances of various substances. These values are actually measured values of films formed by sputtering at room temperature. As shown in Table 1, when vanadium was formed to a thickness of 0.3 μm, the resistivity was 6 × 10 ⁻⁵ Ω · cm, and the sheet resistance was 2Ω / □.

As the positive electrode active material layer 30, a metal oxide thin film capable of detaching and adsorbing lithium ions can be used. For example, lithium manganate (LiMn ₂ O ₄ ), lithium cobaltate (LiCoO ₂ ), lithium nickelate (LiNiO ₂ ), or the like can be used. The film thickness of the positive electrode active material layer 30 is desirably as thin as possible, but is preferably about 1 μm that can secure a charge / discharge capacity.
The solid electrolyte layer 40 may be made of lithium phosphate (Li ₃ PO ₄ ) having good lithium ionic conductivity, a substance obtained by adding nitrogen thereto (LiPON), or the like. The thickness of the solid electrolyte layer 40 is preferably about 1 μm, which is as thin as possible, with reduced generation of pinholes.

The oxide conductive film layer 50 is a substance having a resistivity of 1 × 10 ⁻² Ω · cm or less, such as indium oxide (In ₂ O ₃ ), tin oxide (SnO ₂ ), zinc oxide (ZnO), and the like. As a main component, tin, antimony, fluorine, aluminum, gallium, germanium, zinc and other impurities can be added to form a material having a lower resistance value. Examples include indium oxide containing tin (ITO), tin oxide containing antimony (ATO), tin oxide containing fluorine (FTO), zinc oxide containing aluminum (AZO), and zinc oxide containing gallium (GZO). Etc.
Further, although rare in terms of resources, an oxide of a rare metal having conductivity such as iridium oxide or ruthenium oxide having a lower resistance may be used.
These oxide conductive films can occlude and release lithium ions, and function as a negative electrode of the thin-film solid secondary battery 1. In addition, since these oxide conductive films can have a sheet resistance of 1 kΩ / □ or less, they can function as a current collector thin film. Thus, the oxide conductive film layer 50 of the present invention serves as both a conventional negative electrode active material layer and a negative electrode current collector layer. Therefore, in the present invention, it is not necessary to separately form a negative electrode current collector layer, and the manufacturing cost and the manufacturing time can be reduced.

When the oxide conductive film layer 50 is formed of any one of indium oxide, zinc oxide, tin oxide, ITO, ATO, FTO, AZO, GZO, iridium oxide, and ruthenium oxide, The thickness is preferably 0.1 μm or more.
In addition, when the oxide conductive film 50 is formed by a sputtering method or the like, it is preferable that the manufacturing time is short, and in order to avoid the inconvenience of peeling off after film formation and to ensure good adhesion, The thickness is preferably 10 μm or less.
Therefore, the thickness of the oxide conductive film layer 50 is preferably in the range of 0.1 μm to 10 μm. Note that the oxide conductive film layer 50 may be formed by coating.
Also in this range, it is more preferable that the film thickness be 0.5 μm to 1 μm, which can secure sufficient charge / discharge capacity, reduce sheet resistance, and reduce manufacturing cost and manufacturing time.

Table 1 shows the sheet resistance when the above-mentioned substances have a film thickness of 0.5 μm, all of which are 1 kΩ / □ or less. Moreover, these resistivity is 1 * 10 ^<-2 > (omega ^| ohm) * cm or less. In order to set the film thickness to 0.1 μm or more and the sheet resistance to 1 kΩ / □ or less, it is necessary to form the oxide conductive film 50 with a material having a resistivity of 1 × 10 ⁻² Ω · cm or less.
Note that vanadium pentoxide and niobium pentoxide, which are conventionally used as negative electrode active materials, have resistivity of 5 × 10 ⁵ Ω · cm and 5 × 10 ⁵ Ω · cm, respectively. Therefore, with these materials, it is practically impossible to reduce the sheet resistance to 1 kΩ / □ or less by forming a thin film, and the thin film of these materials cannot function as an extraction electrode. As shown in Table 1, when these materials are formed to a thickness of 0.3 μm, the sheet resistance is on the order of 10 ¹⁰ Ω / □.

The solid electrolyte film 60 is not particularly limited as long as it has high lithium ion conductivity and can be thinned. For example, it is possible to use a film having high lithium ion conductivity, in which powder of lithium phosphate and titanium oxide is mixed with an inorganic binder and processed into a sheet shape.
Further, the surface of the thin-film solid secondary battery 1 exposed to the atmosphere is covered with a moisture prevention film 70 having a moisture prevention effect. In this way, the battery performance can be kept longer. As the moisture prevention film 70, silicon oxide (SiO ₂ ), silicon nitride (SiN _x ), or the like can be used. The thickness of the moisture prevention film 70 is preferably about 0.4 μm which is as thin as possible and has a high moisture prevention effect.

  As a method for forming each thin film, a vacuum film forming method such as a sputtering method, an electron beam vapor deposition method, a heat vapor deposition method, a coating method, or the like can be used. It is preferable to use a vacuum film-forming method that can form a thin film more thinly and uniformly. More preferably, it is preferable to use a sputtering method in which there is little deviation in the atomic composition from the vapor deposition material and uniform film formation is possible.

When the thin-film solid secondary battery 1 is charged, lithium is released from the positive electrode active material layer 30 as ions, and is stored in the oxide conductive film layer 50 through the solid electrolyte layer 40 or the solid electrolyte film 60. Is done. At this time, electrons are emitted from the positive electrode active material layer 30 to the outside.
At the time of discharge, lithium is separated from the oxide conductive film layer 50 as ions, and is inserted in the positive electrode active material layer 30 through the solid electrolyte layer 40 or the solid electrolyte film 60. At this time, electrons are emitted from the oxide conductive film layer 50 to the outside.
The positive electrode active material layer 30 has conductivity secured by the current collector layer 20. In addition, the oxide conductive film layer 50 has low electrical resistance, so that conductivity is ensured.

  Next, examples and comparative examples of the present invention will be described with reference to the drawings. In Table 2, the structure of Examples 1-5 and Comparative Examples 1-3 and the measurement result of charging / discharging characteristics are shown.

Example 1
In Example 1, a current collector layer 20, a positive electrode active material layer 30, a solid electrolyte layer 40, and an oxide conductive film layer 50 are formed in this order on a substrate 10 so as to have the configuration shown in FIG. A solid secondary battery 1 was produced.
As the substrate 10, soda lime glass having a length of 100 mm, a width of 100 mm, and a thickness of 1 mm was used.
The current collector layer 20 was formed by a DC magnetron sputtering method using a vanadium metal target. The film was formed with a DC power of 1 KW and no heating. Thereby, a 0.3 μm vanadium thin film was formed as the current collector layer 20. As shown in Table 1, the vanadium thin film had a sheet resistance of 2Ω / □ and a resistivity of 6 × 10 ⁻⁵ Ω · cm.

The positive electrode active material layer 30 was formed by RF magnetron sputtering using a sintered manganate (LiMn ₂ O ₄ ) sintered target and introducing oxygen. The film was formed with an RF power of 1 KW and no heating. Thereby, a 1 μm lithium manganate thin film was formed.
The solid electrolyte layer 40 was formed by RF magnetron sputtering using a sintered phosphor target of lithium phosphate (Li ₃ PO ₄ ) and introducing nitrogen gas. The film was formed with an RF power of 1 KW and no heating. Thus, a 1 μm lithium phosphate thin film was formed.

The oxide conductive film layer 50 was formed by a DC magnetron sputtering method using an indium oxide (ITO) sintered body target containing tin and introducing oxygen. The film was formed with a DC power of 1 KW and no heating. Thereby, a 0.5 μm ITO thin film was formed. As shown in Table 1, this ITO thin film had a sheet resistance of 10Ω / □ and a resistivity of 5 × 10 ⁻⁴ Ω · cm.
The thin-film solid secondary battery 1 of this example has a thickness of about 3 μm excluding the substrate 10.

In order to evaluate the battery performance of the thin film solid secondary battery 1 obtained as described above, charge / discharge characteristics were measured using a charge / discharge measuring instrument.
Measurement conditions were such that the current during charging and discharging was 400 μA, and the voltage at which charging and discharging were terminated was 3.5 V and 0.3 V, respectively. As a result, it was confirmed that repeated charge / discharge operations were exhibited.
As shown in Table 2, the discharge start voltage at the 10th cycle in which the charge / discharge operation was stabilized was 3.2 V, and the charge capacity and the discharge capacity were 958 μAh and 926 μAh, respectively. FIG. 7 shows a graph of charge / discharge characteristics at the 10th cycle in which the charge / discharge operation is stably performed.
In this example, charge / discharge measurement was performed up to 100 cycles, but it was confirmed that a stable and substantially constant charge / discharge curve was exhibited.

(Example 2)
In Example 2, the oxide conductive film layer 50, the solid electrolyte layer 40, the positive electrode active material layer 30, and the current collector layer 20 are formed on the substrate 10 in this order by the sputtering method so as to form the structure of FIG. A solid secondary battery 1 was produced.
As the substrate 10, soda lime glass having a length of 100 mm, a width of 100 mm, and a thickness of 1 mm was used.
The materials, film forming conditions, thicknesses, etc. of the other layers are the same as those in the first embodiment.
The battery performance of the thin film solid secondary battery 1 obtained as described above was evaluated by charge / discharge measurement. The measurement conditions for the charge / discharge measurement are the same as in Example 1 above.
As a result, as shown in Table 2, the discharge start voltage at the 10th cycle was 3.1 V, and the charge capacity and the discharge capacity were 966 μAh and 931 μAh, respectively.
Moreover, although charging / discharging measurement was performed to 100 cycles, it was confirmed that it shows a stable and substantially constant charging / discharging curve.

(Example 3)
In Example 3, a solid electrolyte film 60 having a thickness of 50 μm was cut into a size of 100 mm in length and 100 mm in width so as to form the configuration of FIG. 3, set in a sputtering apparatus, and first, the positive electrode active material layer 30 was formed on one surface. The current collector layer 20 was sequentially formed. The material, film forming conditions, thickness, and the like of each layer are the same as those in the first embodiment.
Next, the solid electrolyte film 60 on which the positive electrode active material layer 30 and the current collector layer 20 were formed was taken out from the film formation apparatus and set upside down to form the oxide conductive film layer 50. The materials, film forming conditions, thicknesses, etc. used for each layer are the same as those in the first embodiment.
The battery performance of the thin film solid secondary battery 1 obtained as described above was evaluated by charge / discharge measurement. The measurement conditions for the charge / discharge measurement are the same as in Example 1 above.
As a result, as shown in Table 2, the discharge start voltage at the 10th cycle was 2.9 V, and the charge capacity and the discharge capacity were 904 μAh and 899 μAh, respectively.
Moreover, although charging / discharging measurement was performed to 100 cycles, it was confirmed that it shows a stable and substantially constant charging / discharging curve.

(Example 4)
In Example 4, the current collector layer 20, the positive electrode active material layer 30, the solid electrolyte layer 40, and the oxide conductive film layer 50 are formed in this order on the substrate 10 so as to have the configuration shown in FIG. A solid secondary battery 1 was produced.
As the substrate 10, soda lime glass having a length of 100 mm, a width of 100 mm, and a thickness of 1 mm was used.
For the oxide conductive film layer 50, zinc oxide (AZO) containing aluminum was used. The AZO film was formed under the same film formation conditions as the ITO film of Example 1 to form a 0.5 μm AZO thin film. As shown in Table 1, the sheet resistance of this AZO thin film was 60Ω / □, and the resistivity was 3 × 10 ⁻³ Ω · cm.
The materials, film forming conditions, thicknesses, and the like of each layer other than the oxide conductive film layer 50 are the same as those in the first embodiment.
The battery performance of the thin film solid secondary battery 1 obtained as described above was evaluated by charge / discharge measurement. The measurement conditions for the charge / discharge measurement are the same as in Example 1 above.
As a result, as shown in Table 2, the discharge start voltage at the 10th cycle was 3.0 V, and the charge capacity and the discharge capacity were 921 μAh and 908 μAh, respectively.
Moreover, although charging / discharging measurement was performed to 100 cycles, it was confirmed that it shows a stable and substantially constant charging / discharging curve.

(Example 5)
In Example 5, a current collector layer 20, a positive electrode active material layer 30, a solid electrolyte layer 40, and an oxide conductive film layer 50 are formed in this order on the substrate 10 so as to have the configuration shown in FIG. A solid secondary battery 1 was produced.
As the substrate 10, soda lime glass having a length of 100 mm, a width of 100 mm, and a thickness of 1 mm was used.
For the oxide conductive film layer 50, tin oxide (ATO) containing antimony was used. The ATO film was formed under the same film forming conditions as those of the ITO film of Example 1 to form a 0.5 μm ATO thin film. As shown in Table 1, the sheet resistance of this ATO thin film was 40Ω / □, and the resistivity was 2 × 10 ⁻³ Ω · cm.
The materials, film forming conditions, thicknesses, and the like of each layer other than the oxide conductive film layer 50 are the same as those in the first embodiment.
The battery performance of the thin film solid secondary battery 1 obtained as described above was evaluated by charge / discharge measurement. The measurement conditions for the charge / discharge measurement are the same as in Example 1 above.
As a result, as shown in Table 2, the discharge start voltage at the 10th cycle was 3.1 V, and the charge capacity and the discharge capacity were 945 μAh and 922 μAh, respectively.
Moreover, although charging / discharging measurement was performed to 100 cycles, it was confirmed that it shows a stable and substantially constant charging / discharging curve.

(Comparative Example 1)
Next, as Comparative Example 1, a current collector layer 20, a positive electrode active material layer 30, a solid electrolyte layer 40, a negative electrode active material layer 80, and a current collector layer 20 are sputtered in this order on a substrate 10 as shown in FIG. The thin film solid secondary battery 1 was produced by the method.
As the substrate 10, soda lime glass having a length of 100 mm, a width of 100 mm, and a thickness of 1 mm was used.
The negative electrode active material layer 80 was formed by RF magnetron sputtering using a sintered target of vanadium pentoxide (V ₂ O ₅ ). The film was formed with 1 KW RF power and no heating. Thereby, a 0.25 μm vanadium pentoxide thin film was formed. As shown in Table 1, the vanadium pentoxide thin film had a sheet resistance of 2 × 10 ¹⁰ Ω / □ and a resistivity of 5 × 10 ⁵ Ω · cm.
The materials, film forming conditions, thicknesses, and the like of each layer other than the negative electrode active material layer 80 are the same as those in the first embodiment.

The battery performance of the thin film solid secondary battery 101 obtained as described above was evaluated by charge / discharge measurement. The measurement conditions for the charge / discharge measurement are the same as in Example 1 above.
As a result, as shown in Table 2, the discharge start voltage at the 10th cycle was 3.2 V, and the charge capacity and the discharge capacity were 981 μAh and 931 μAh, respectively.
Moreover, the charge / discharge measurement was performed up to 100 cycles.

(Comparative Example 2)
As Comparative Example 2, a current collector layer 20, a negative electrode active material layer 80, a solid electrolyte layer 40, a positive electrode active material layer 30, and a current collector layer 20 are formed in this order on a substrate 10 as shown in FIG. The thin film solid secondary battery 1 was formed.
As the substrate 10, soda lime glass having a length of 100 mm, a width of 100 mm, and a thickness of 1 mm was used.
The material of each layer, film forming conditions, thickness, and the like are the same as in Comparative Example 1 above.
The battery performance of the thin film solid secondary battery 101 obtained as described above was evaluated by charge / discharge measurement. The measurement conditions for the charge / discharge measurement are the same as in Example 1 above.
As a result, as shown in Table 2, the discharge start voltage at the 10th cycle was 3.2 V, and the charge capacity and the discharge capacity were 955 μAh and 926 μAh, respectively.
Moreover, the charge / discharge measurement was performed up to 100 cycles.

(Comparative Example 3)
As Comparative Example 3, as shown in FIG. 6, an electrolyte film having a thickness of 50 μm was cut into a size of 100 mm in length and 100 mm in width, set in a sputtering apparatus, and on one side, a positive electrode active material layer 30 and a current collector The layer 20 was sequentially formed, and then the negative electrode active material layer 80 and the current collector layer 20 were sequentially formed on the opposite surface. The material of each layer, film forming conditions, thickness, and the like are the same as in Comparative Example 1 above.
The battery performance of the thin film solid secondary battery 101 obtained as described above was evaluated by charge / discharge measurement. The measurement conditions for the charge / discharge measurement are the same as in Example 1 above.
As a result, as shown in Table 2, the discharge start voltage at the 10th cycle was 2.9 V, and the charge capacity and the discharge capacity were 912 μAh and 889 μAh, respectively.
Moreover, the charge / discharge measurement was performed up to 100 cycles.

In Comparative Examples 1, 2, and 3, the negative electrode active material layer 80 and the current collector layer 20 are laminated on the negative electrode side. In contrast, the first, second, and third embodiments are different in that only the oxide conductive film layer 50 is provided on the negative electrode side instead of the negative electrode active material layer 80 and the current collector layer 20. Except this point, Example 1 and Comparative Example 1, Example 2 and Comparative Example 2, Example 3 and Comparative Example 3 have the same film configuration.
As shown in Table 2, when Example 1 and Comparative Example 1, Example 2 and Comparative Example 2, and Example 3 and Comparative Example 3 are respectively compared, both have the same charge / discharge capacity and discharge start voltage. And it turns out that the thin film solid secondary battery 1 of Examples 1-3 can be used as a secondary battery.
In Examples 1, 4 and 5, an ITO thin film, an AZO thin film, and an ATO thin film were used as the oxide conductive film layer 50, respectively, but all had the same charge / discharge capacity and discharge start voltage. It can be seen that it can be used as a secondary battery.
Moreover, in the thin film solid secondary battery 1 of Examples 1-5 as mentioned above, charging / discharging was repeated 100 times, but charge / discharge capacity and discharge start were performed similarly to the thin film solid secondary battery 101 of Comparative Examples 1-3. It was found that the voltage does not decrease and can be used repeatedly.

As described above, the thin film solid secondary battery 1 of the present example is different from the configuration of the thin film solid secondary battery 101 of the comparative example in that instead of providing the negative electrode active material layer 80 and the current collector layer 20, oxide conductive The film layer 50 was provided. This simplifies the configuration, enables production with less production time and processes, and reduces production costs.
Moreover, it turned out that the thin film solid secondary battery 1 of a present Example has the charging / discharging capacity | capacitance, discharge start voltage, and repeated use characteristic equivalent to the thin film solid secondary battery 101 of a comparative example.
Moreover, the thin film solid secondary battery 1 of a present Example can be produced without using vanadium pentoxide.

(Example 6)
In Example 6, a moisture prevention film 70 having a moisture prevention effect on the surfaces of the thin film solid secondary battery 1 of Examples 1 to 5 and the thin film solid secondary battery 101 of Comparative Examples 1 to 3 exposed to the atmosphere. Each of the silicon nitride thin films was formed by sputtering.
That is, in Examples 1, 4, and 5, the moisture prevention film 70 was formed on the exposed surface of the oxide conductive film layer 50 as shown in FIG. In Example 2, a moisture prevention film 70 was formed on the exposed surface of the current collector layer 20 as shown in FIG. In Example 3, the moisture prevention film 70 was formed on the exposed surfaces of the current collector layer 20 and the oxide conductive film layer 50 as shown in FIG.
In Comparative Examples 1 and 2, a moisture prevention film 70 was formed on the exposed surface of the current collector layer 20 as shown in FIGS. In Comparative Example 3, as shown in FIG. 6, the moisture prevention film 70 was formed on the exposed surfaces of the current collector layers 20 on both sides.
The moisture prevention film 70 was formed by introducing a nitrogen gas by an RF magnetron sputtering method using a Si semiconductor target. The film was formed with an RF power of 1 KW and no heating. Thereby, a 0.4 μm silicon nitride thin film was formed.

  When the charge / discharge characteristics of the thin-film solid secondary batteries 1 and 101 coated with the moisture prevention film 70 obtained as described above were measured immediately after the production, the above Examples 1 to 5 and Comparative Examples 1 to 1 were compared. The charge / discharge voltage and charge / discharge capacity equivalent to those of the thin-film solid secondary battery 1,101 not coated with the moisture prevention film 70 of Example 3 were obtained.

About the thin film solid secondary battery 1 of Example 1 thru | or Example 5, and the thin film solid secondary battery 101 of Comparative Example 1 thru | or Comparative Example 3, the charging / discharging characteristic was measured again about one month later.
In the thin-film solid secondary batteries 101 of Comparative Examples 1 to 3 that were not covered with the moisture prevention film 70, as shown in Table 2, the discharge capacity was reduced by about 25%.
On the other hand, in the thin-film solid secondary battery 1 of Examples 1 to 5 that did not cover the moisture prevention film 70, the discharge capacity was only reduced by 2 to 4% as shown in Table 2.
In addition, in the thin-film solid secondary battery 1,101 coated with the moisture prevention film 70, no decrease in charge / discharge capacity was observed in the measurement after one month.

As described above, in the thin-film solid secondary battery 101 that does not cover the moisture prevention film 70, the battery characteristics deteriorated because the vanadium pentoxide used for the negative electrode active material layer 80 absorbs moisture in the atmosphere. On the other hand, in the thin-film solid secondary battery 1 that does not cover the moisture prevention film 70, moisture prevention is achieved by using ITO, AZO, and ATO as the oxide conductive film layer 50 that also serves as the negative electrode active material and the current collector. It can be seen that even without coating the film 70, the deterioration of the battery characteristics is greatly reduced, and there is a moisture prevention effect.
Further, the thin-film solid secondary batteries 1 and 101 coated with the moisture prevention film 70 have a large effect of preventing moisture and have little deterioration in battery characteristics.
As described above, the thin film solid secondary battery 1 of this example has durability against moisture in the air and the battery characteristics are not easily deteriorated as compared with the thin film solid secondary battery 101 of the comparative example. I understand. Therefore, the thin film solid secondary battery 1 of the present embodiment does not necessarily need to be coated with the moisture preventing film 70 having a moisture preventing effect.

(Example 7)
In Example 7, five film-shaped thin film solid secondary batteries 1 of Example 3 were produced. Then, these five film-like thin film solid secondary batteries 1 were stacked so that the opposite poles were in contact with each other and thermocompression bonded with a laminating machine to produce a thin film solid secondary battery 2 having a serial stacked structure shown in FIG. . That is, the five thin film solid secondary batteries 1 are laminated so that the positive electrode current collector layer 20 and the oxide conductive film layer 50 are in contact with the adjacent thin film solid secondary battery 1. Yes. Further, a moisture prevention film 70 was further formed on the outermost layer of the thin film solid secondary battery 2.
For the thin-film solid secondary battery 2 shown in FIG. 8 produced as described above, a conductive tape made of copper is used as a lead electrode for the positive electrode current collector layer 20 and the negative oxide conductive film layer 50, respectively. The battery performance was evaluated by charge / discharge measurement.
As a result, compared with Example 3, the charge capacity and the discharge capacity were substantially the same, the discharge start voltage was about 5 times, and the effect of series connection was observed.

(Example 8)
In Example 8, five film-form thin film solid secondary batteries 1 of Example 3 were produced. Then, these five film-like thin film solid secondary batteries 1 were stacked so that the same poles were in contact with each other, and thermocompression bonded with a laminating machine to produce a thin film solid secondary battery 3 having a parallel stacked structure shown in FIG. . That is, the five thin-film solid secondary batteries 1 are stacked so that the current collector layers 20 on the positive electrode side or the oxide conductive film layers 50 are in contact with the adjacent thin-film solid secondary battery 1. Has been. Further, a moisture prevention film 70 was further formed on the outermost layer of the thin film solid secondary battery 2. At that time, a conductive tape made of copper is attached between each film-like thin film solid secondary battery 1 and the outermost positive electrode current collector layer 20 and the negative electrode oxide conductive film layer 50, respectively. The lead electrode was used.
For the thin-film solid secondary battery 3 shown in FIG. 9 produced as described above, the same polarity was connected and the battery performance was evaluated by charge / discharge measurement.
As a result, compared with Example 3, the discharge start voltage was substantially the same, the charge capacity and the discharge capacity were about 5 times, and the effect of parallel connection was seen.
In addition, in Example 7, 8, although it was set as the structure which laminated | stacked the five film-form thin film solid secondary batteries 1, it can be set as the structure which laminated | stacked not only this but two or more sheets.

Example 9
In Example 9, a secondary battery in which a current collector layer 20, a positive electrode active material layer 30, a solid electrolyte layer 40, and an oxide conductive film layer 50 are laminated in this order on a substrate 10 having the configuration of FIG. A plurality of cells 5 were further laminated to produce a thin film solid secondary battery 2 having a serially laminated structure.
The materials, film formation conditions, thickness, and the like of the current collector layer 20, the positive electrode active material layer 30, the solid electrolyte layer 40, and the oxide conductive film layer 50 are the same as those in the first embodiment. Each layer was formed by sequentially laminating by a sputtering method. In addition, a moisture prevention film 70 was formed as the outermost layer. In this embodiment, the secondary battery cell 5 is laminated on the substrate 10 in five layers.
That is, in the thin film solid secondary battery 2 having the serial stacked structure, the adjacent secondary battery cells 5 are arranged so that the current collector layer 20 on one positive electrode side and the oxide conductive film layer 50 on the other side are in contact with each other. Are stacked.
For the thin-film solid secondary battery 2 shown in FIG. 10 manufactured as described above, a conductive film made of copper is used as a lead electrode, and the negative electrode oxide conductive film layer 50 and the positive electrode current collector on the substrate 10 side. The battery performance was evaluated by charge / discharge measurement by pasting each layer 20. The current collector layer 20 directly laminated on the substrate 10 was formed so that a part of the current collector layer 20 was exposed, and a conductive tape was attached to the exposed part. Further, a portion exposed to the outside was also provided on the oxide conductive film layer 50 of the outermost negative electrode, and a conductive tape was attached.
As a result, compared with Example 1, the charge capacity and the discharge capacity were substantially the same, the discharge start voltage was about 5 times, and the effect of series connection was seen.
Although not shown, a plurality of secondary battery cells in which the oxide conductive film layer 50, the solid electrolyte layer 40, the positive electrode active material layer 30, and the current collector layer 20 are stacked in this order are stacked on the substrate 10. Similarly, the thin film solid-state secondary battery 2 having a serial stacked structure formed in the same manner has substantially the same charge capacity and discharge capacity as the first embodiment, and the discharge start voltage is about five times higher. The effect of was seen.

(Example 10)
In Example 10, a secondary battery in which a current collector layer 20, a positive electrode active material layer 30, a solid electrolyte layer 40, and an oxide conductive film layer 50 are stacked in this order on a substrate 10 to have the configuration of FIG. The secondary battery cell 6 is formed by forming the cell 5 and further laminating the oxide conductive film layer 50, the solid electrolyte layer 40, the positive electrode active material layer 30, and the current collector layer 20 in this order on the secondary battery cell 5. And a secondary battery cell 5, a secondary battery cell 6,... In this order were stacked in this order to produce a thin film solid secondary battery 3 having a parallel stacked structure. The materials, film formation conditions, thickness, and the like of the current collector layer 20, the positive electrode active material layer 30, the solid electrolyte layer 40, and the oxide conductive film layer 50 are the same as those in the first embodiment. Each layer was formed by sequentially laminating by a sputtering method. In addition, a moisture prevention film 70 was formed as the outermost layer. In this example, five layers of secondary battery cells 5, 6, 5, 6, and 5 were stacked on the substrate 10.
That is, in the thin film solid secondary battery 3 having the parallel stacked structure, the adjacent secondary battery cells 5 and 6 are arranged such that the negative electrode conductive film layers 50 and the positive electrode current collector layers 20 are in contact with each other. Are stacked.

Further, in the oxide conductive film layer 50 and the current collector layer 20 with which the secondary battery cells 5 and 6 are in contact, an exposed portion where a thin film is not further laminated is provided in part, and a lead electrode is connected to the exposed portion. Then, the current collector layer 20 of each secondary battery cell 5, 6 is connected to form one lead electrode, and the oxide conductive film layer 50 of each secondary battery cell 5, 6 is connected to the other lead electrode. An electrode was obtained.
With respect to the thin-film solid secondary battery 3 shown in FIG. 11 manufactured as described above, the same polarity was connected and the battery performance was evaluated by charge / discharge measurement.
As a result, compared with Example 1, the discharge start voltage was substantially the same, the charge capacity and the discharge capacity were about 5 times, and the effect of parallel connection was seen.
Although not shown, the secondary battery cell 6 is first laminated on the substrate 10, the secondary battery cell 5 is laminated thereon, and the secondary battery cell 6, the secondary battery cell 5,. The thin film solid secondary battery 3 having the parallel stacked structure was stacked in order, and it was confirmed that the performance was the same as that of the thin film solid secondary battery 3 having the parallel stacked structure having the configuration shown in FIG.
In addition, in Example 9, 10, although it was set as the 5 layer structure, it can be set as the structure which laminated | stacked the secondary battery cell 5 and 6 of multiple layers not only in this.
In the embodiment of FIG. 11, the secondary battery cells 5 and 6 are formed so that the oxide conductive film layers 50 or the current collector layers 20 are in contact with each other. That is, the oxide conductive film layer 50 and the current collector layer 20 are continuously formed. In the present invention, the secondary battery cells 5 and 6 are laminated by forming the oxide conductive film layer 50 and the current collector layer 20 individually in each of the secondary battery cells 5 and 6, and continuously. In other words, both the oxide conductive film layer 50 and the current collector layer 20 to be laminated are formed in one layer.
In Examples 9 and 10, an electrode film for electrode drawing is separately formed between the adjacent secondary battery cell 5 and secondary battery cell 6, and the secondary battery cell 5 and the secondary battery cell 6 are sequentially formed. You may laminate.

It is sectional drawing of the thin film solid secondary battery which concerns on an Example. It is sectional drawing of the thin film solid secondary battery which concerns on an Example. It is sectional drawing of the thin film solid secondary battery which concerns on an Example. It is sectional drawing of the thin film solid secondary battery which concerns on a comparative example. It is sectional drawing of the thin film solid secondary battery which concerns on a comparative example. It is sectional drawing of the thin film solid secondary battery which concerns on a comparative example. It is a graph of the charging / discharging characteristic of the thin film solid secondary battery which concerns on an Example. It is sectional drawing of the thin film solid secondary battery which concerns on an Example. It is sectional drawing of the thin film solid secondary battery which concerns on an Example. It is sectional drawing of the thin film solid secondary battery which concerns on an Example. It is sectional drawing of the thin film solid secondary battery which concerns on an Example.

Explanation of symbols

1, 2, 3, 101 Thin-film solid secondary battery, 5, 6 Secondary battery cell, 10 Substrate, 20 Current collector layer, 30 Positive electrode active material layer, 40 Solid electrolyte layer, 50 Oxide conductive film layer, 60 Solid Electrolyte film, 70 moisture prevention film, 80 negative electrode active material layer

Claims (11)

On a substrate laminated, and the positive electrode collector layer, a positive electrode active material layer, a solid electrolyte layer, and the oxide conductive layer functioning as an anode active material layer having a function of a negative electrode collector layer, but in this order And
The oxide conductive film layer is made of a material having a resistivity of 1 × 10 ⁻² Ω · cm or less. On a substrate, laminating an oxide conductive film layer serving as a negative electrode active material layer having a function of a negative electrode collector layer, a solid electrolyte layer, a cathode active material layer, and the positive electrode collector layer, but in this order And
The oxide conductive film layer is made of a material having a resistivity of 1 × 10 ⁻² Ω · cm or less. An oxide conductive film layer functioning as a negative electrode active material layer having the function of a negative electrode current collector layer is formed on one surface of the solid electrolyte film, and a positive electrode active material layer and a positive electrode current collector layer are formed on the other surface. Laminated in this order,
The oxide conductive film layer is made of a material having a resistivity of 1 × 10 ⁻² Ω · cm or less.   A thin-film solid secondary battery comprising the thin-film solid secondary battery according to claim 3 laminated so that the positive electrode current collector layer and the oxide conductive film layer are in contact with each other. .   The thin film solid secondary battery according to claim 3, wherein the thin film solid secondary battery is stacked so that the positive electrode current collector layers and the oxide conductive film layers are in contact with each other. battery. On a substrate laminated, and the positive electrode collector layer, a positive electrode active material layer, a solid electrolyte layer, and the oxide conductive layer functioning as an anode active material layer having a function of a negative electrode collector layer, but in this order A thin film solid secondary battery in which a plurality of secondary battery cells are stacked,
The secondary battery cell is laminated so that the positive electrode current collector layer and the oxide conductive film layer are in contact with each other,
The oxide conductive film layer is made of a material having a resistivity of 1 × 10 ⁻² Ω · cm or less. On a substrate laminated, and the positive electrode collector layer, a positive electrode active material layer, a solid electrolyte layer, and the oxide conductive layer functioning as an anode active material layer having a function of a negative electrode collector layer, but in this order A thin film solid secondary battery in which a plurality of secondary battery cells are stacked,
The secondary battery cells are stacked such that the positive electrode current collector layers and the oxide conductive film layers are in contact with each other,
The oxide conductive film layer is made of a material having a resistivity of 1 × 10 ⁻² Ω · cm or less.   The thin film solid state secondary battery according to claim 1, wherein the positive electrode active material layer is an active material layer including a metal oxide containing lithium as a constituent element.   The material forming the oxide conductive film layer is any one of indium oxide, tin oxide, and zinc oxide, or any of them as a main component. The thin film solid secondary battery according to one item.   The thin film solid secondary battery according to any one of claims 1 to 7, wherein a moisture prevention film is laminated on the surface.   The said positive electrode collector layer, the said positive electrode active material layer, the said solid electrolyte layer, and the said oxide electrically conductive film layer were formed by sputtering method, The Claim 1 characterized by the above-mentioned. Thin film solid secondary battery.

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