JP2008103292A - All-solid battery for household electric appliance - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an all-solid battery for household electric appliance which has no liquid junction and has high heat resistance and safety, in which battery characteristics can be maintained against repeated charge and discharge, and high output is obtained, and which has high ion conductivity. <P>SOLUTION: This is the all-solid battery constituted by connecting a plurality of numbers of all-solid battery elements composed by interposing a solid electrolyte layer between a positive electrode and a negative electrode, and this is the all-solid battery for household electrical appliance of which an operating potential is 30 V or less. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an all-solid-state battery for home appliances.

Batteries are important as a main power source for portable electronic devices. In particular, button batteries and gum-type batteries are small or thin, and thus are useful for light, thin and small electronic devices. Such a small battery is generally loaded in a battery case provided in an electronic device, and a light and thin battery is desired.
As batteries used for such applications, demand for secondary batteries such as high performance lithium batteries is increasing, and development of secondary batteries with high safety and high performance is desired.
In order to ensure the safety of the lithium battery, it is effective to use an inorganic solid electrolyte instead of the organic solvent electrolyte. Inorganic solid electrolytes are generally nonflammable or flame retardant in nature and are safer materials than commonly used organic solvent electrolytes. Therefore, development of an all-solid lithium battery with high safety using the electrolyte is desired.

In an all-solid-state lithium battery, conventionally, a binder is used to form a molded body of a solid electrolyte layer such as a sheet or a thin film. However, when a binder is mixed in the solid electrolyte layer in order to obtain a molded body, there is a problem that the ion conduction path is cut and the ionic conductivity of the solid electrolyte layer is lowered.
As described above, an electrolyte layer made of only a solid electrolyte has been studied as a member constituting an all-solid lithium battery, but it is difficult to form a single-layer thin film made of only a solid electrolyte. In addition, when the battery is operated, the lithium ion conductivity in the electrolyte depends on the thickness of the electrolyte layer, and the thinner the electrolyte layer, the higher the lithium ion conductivity. Therefore, it is desired to reduce the thickness of the solid electrolyte layer. .

In particular, sulfide-based inorganic solid electrolytes are known to have higher ionic conductivity than other inorganic compounds, and the inorganic solid electrolytes described in Patent Document 1 and the like can be used. Specifically, an inorganic solid electrolyte in which Li ₃ PO ₄ , a halogen, and a halogen compound are appropriately added to an inorganic solid electrolyte composed of a combination of Li ₂ S and SiS ₂ , GeS ₂ , P ₂ S ₅ , B ₂ S _3. Can be used.

Japanese Patent Laid-Open No. 4-202024

  In view of the above situation, the present invention has no liquid junction, has high heat resistance, high safety, can maintain battery characteristics against repeated charge and discharge, and has high ion conductivity with high output. It aims at providing the all-solid-state battery for household appliances.

  As a result of intensive studies, the present inventors have found that the above problem can be solved by using a solid electrolyte layer made of a specific material. The present invention has been completed based on such findings.

That is, the present invention
[1] An all-solid battery in which a plurality of all-solid battery elements each having a solid electrolyte layer interposed between a positive electrode and a negative electrode are connected, and has an operating potential of 30 V or less,
[2] The solid electrolyte contains a lithium element, a phosphorus element, and a sulfur element. In X-ray diffraction (CuKα: λ = 1.5418Å), 2θ = 17.8 ± 0.3 deg, 18.2 ± 0.3 deg. 19.8 ± 0.3 deg, 21.8 ± 0.3 deg, 23.8 ± 0.3 deg, 25.9 ± 0.3 deg, 29.5 ± 0.3 deg, 30.0 ± 0.3 deg. The all-solid-state battery for home appliances according to the above [1], which is a lithium ion conductive sulfide-based crystallized glass having a peak,
[3] The solid electrolyte contains lithium element, phosphorus element and sulfur element, and the solid ³¹ P-NMR spectrum of the solid electrolyte is at positions of 90.9 ± 0.4 ppm and 86.5 ± 0.4 ppm. The all-solid-state battery for household appliances as described in said [1] which has a peak resulting from a crystal | crystallization and the ratio of the said crystal | crystallization occupied to the said solid electrolyte is 60-100 mol%,
[4] The above [1] to [3], which are coated with an exterior material, and the exterior material is further coated with an adsorbent and / or an alkaline substance-containing material on an exterior body made of a thermoplastic resin or a thermosetting resin. All-solid-state battery for home appliances according to any one of
[5] Any of the above [1] to [3], which is covered with an exterior material, the exterior material is made of a thermoplastic resin or a thermosetting resin, and the exterior material contains an adsorbent and / or an alkaline substance. All-solid-state batteries for home appliances according to [6], and [6] a support plate having a plurality of through holes on the side not facing the solid electrolyte layer of the positive electrode and the negative electrode, respectively, and supported through corresponding through holes of each support plate The all-solid-state battery for home appliances according to any one of the above [1] to [5], wherein a pressure of 1.5 to 200 MPa is applied to the all-solid-state battery element by connecting and tightening the plates;
Is to provide.

  According to the present invention, there is no liquid junction, heat resistance, high safety, battery characteristics can be maintained for repeated charging and discharging, and high output can be obtained. A solid state battery can be provided.

The all solid state battery of the present invention is an all solid state battery constructed by connecting a plurality of all solid state battery elements having a solid electrolyte layer interposed between a positive electrode and a negative electrode, and has an operating potential of 30 V or less. It is an all-solid-state battery.
Here, as the solid electrolyte to be used, a lithium ion conductive sulfide-based crystallized glass containing a lithium element, a phosphorus element, and a sulfur element and having an X-ray diffraction peak having a specific pattern is used (hereinafter referred to as “the solid electrolyte”). Sometimes referred to as “solid electrolyte A”).

The lithium ion conductive sulfide-based crystallized glass contains lithium, phosphorus and sulfur elements as constituent components, and in X-ray diffraction (CuKα: λ = 1.5418Ｃｕ), 2θ = 17.8 ± 0.3 deg. , 18.2 ± 0.3 deg, 19.8 ± 0.3 deg, 21.8 ± 0.3 deg, 23.8 ± 0.3 deg, 25.9 ± 0.3 deg, 29.5 ± 0.3 deg, 30 It has a diffraction peak at 0.0 ± 0.3 deg.
In the above eight regions, a crystal structure having a diffraction peak has not been observed in the past, indicating that this sulfide-based crystallized glass has a novel crystal structure. A sulfide-based crystallized glass having such a crystal structure has extremely high lithium ion conductivity.

This crystal structure can be manifested by firing a sulfide-based glass having a composition of Li ₂ S: 68 to 74 mol% and P ₂ S ₅ : 26 to 32 mol% at 150 to 360 ° C. .

As the starting material Li ₂ S, for example, Li ₂ S obtained by reacting lithium hydroxide and hydrogen sulfide in an aprotic organic solvent is washed at a temperature of 100 ° C. or higher using an organic solvent. A purified product can be used.
Specifically, Li ₂ S is preferably produced by the production method disclosed in Japanese Patent Application Laid-Open No. 7-330312, and this Li ₂ S is purified by the method described in Japanese Patent Application No. 2003-363403. preferable.

Since this Li ₂ S production method can obtain high-purity lithium sulfide by a simple means, the raw material cost of sulfide-based crystallized glass can be reduced. In addition, the above purification method is economically advantageous because it can remove sulfur oxide, lithium N-methylaminobutyrate (hereinafter referred to as LMAB), and the like, which are impurities contained in Li ₂ S, by a simple treatment. At the same time, the obtained solid electrolyte for a lithium secondary battery using high-purity lithium sulfide can suppress a decrease in performance due to purity, and as a result, an excellent lithium secondary battery (solid battery) can be obtained. .
Incidentally, the total amount of sulfur oxides contained in the Li ₂ S, preferably 0.15 mass% or less, LMAB is preferably not more than 0.1 mass%.

P ₂ S ₅ can be used without particular limitation as long as it is industrially manufactured and sold.
Further, instead of P ₂ S ₅ , simple phosphorus (P) and simple sulfur (S) in a corresponding molar ratio can be used. As a result, the sulfide-based crystallized glass of the present invention can be produced from an easily available and inexpensive material. Simple phosphorus (P) and simple sulfur (S) can be used without particular limitation as long as they are industrially produced and sold.

The composition of the sulfide-based crystallized glass of the present invention is Li ₂ S: 68 to 74 mol% and P ₂ S ₅ : 32 to 26 mol%. If the blending ratio is out of the range, the crystal structure peculiar to the present invention is not exhibited, the ionic conductivity is decreased, and the performance as a solid electrolyte is not exhibited. In particular, the blending amount of Li ₂ S is preferably 68 to 73 mol%, and the blending amount of P ₂ S ₅ is preferably 32 to 27 mol%.

In addition, as long as the crystal structure of the crystallized glass of the present invention can be expressed, the starting materials other than P ₂ S ₅ and Li ₂ S are Al ₂ S ₃ , B ₂ S ₃ , GeS ₂ and SiS _2. At least one sulfide selected from the group consisting of: When such a sulfide is added, a more stable glass can be produced when a sulfide-based glass is formed.
Similarly, at least one orthooxo acid selected from the group consisting of Li ₃ PO ₄ , Li ₄ SiO ₄ , Li ₄ GeO ₄ , Li ₃ BO ₃ and Li ₃ AlO ₃ in addition to Li ₂ S and P ₂ S _5. Lithium can be included. When such lithium orthooxo acid is included, the glass in the crystallized glass can be stabilized.
Furthermore, in addition to Li ₂ S and P ₂ S ₅ , at least one kind of the above-described sulfide can be included, and further, at least one kind of the above-described lithium orthooxo acid can be included.

Examples of the method of using the mixture of the starting materials as the sulfide glass include a mechanical milling process (hereinafter sometimes referred to as MM process) or a melt quenching method.
It is preferable to form a sulfide-based glass using the MM treatment because the glass generation region can be expanded. Further, since the heat treatment performed by the melt quenching method is not necessary and can be performed at room temperature, the manufacturing process can be simplified.

When forming the sulfide-based glass by the melt quenching method or the MM treatment, it is preferable to use an atmosphere of an inert gas such as nitrogen. This is because water vapor, oxygen and the like easily react with the starting material.
In the MM treatment, it is preferable to use a ball mill. This is because large mechanical energy can be obtained.
As the ball mill, it is preferable to use a planetary ball mill. In the planetary ball mill, since the base plate revolves while the pot rotates, very high impact energy can be generated efficiently.

  The conditions for the MM treatment may be adjusted as appropriate depending on the equipment to be used. However, the faster the rotation speed, the faster the generation rate of the sulfide-based glass, and the longer the rotation time, the higher the conversion rate of the raw material to the sulfide-based glass. Get higher. For example, when a general planetary ball mill is used, the rotation speed may be several tens to several hundreds of revolutions / minute, and the treatment may be performed for 0.5 hours to 100 hours.

  The obtained sulfide glass is fired and crystallized to obtain the lithium ion conductive sulfide crystallized glass of the present invention. The baking temperature at this time shall be 150 to 360 degreeC. Below 150 ° C., crystallization does not proceed because the temperature is below the glass transition point of the sulfide-based glass. On the other hand, when it exceeds 360 ° C., the above-described crystal glass having a crystal structure unique to the present invention is not generated, and the crystal structure described in Patent Document 1 is changed. The firing temperature is particularly preferably in the range of 200 ° C to 350 ° C. The firing time is not particularly limited as long as the crystal is generated, and may be instantaneous or long. Moreover, there is no limitation in particular also about the temperature rising pattern to baking temperature.

The sulfide-based crystallized glass of the present invention has a decomposition voltage of at least 5 V or more, a nonflammable inorganic solid, and a lithium ion transport number of 1 while maintaining a property of 10 ⁻³ S / cm level at room temperature. It exhibits an extremely high lithium ion conductivity that has never been seen before. Therefore, it is extremely suitable as a material for a solid electrolyte of a lithium battery.
Moreover, the all-solid-state battery using the solid electrolyte (solid electrolyte A) of the present invention having the above characteristics has high energy density, and is excellent in safety and charge / discharge cycle characteristics.

Further, as a solid electrolyte that can be suitably used in the present invention, a solid electrolyte containing a lithium (Li) element, a phosphorus (P) element, and a sulfur (S) element, the following conditions (1) and (2) are satisfied. A material that satisfies this condition can also be mentioned (hereinafter sometimes referred to as “solid electrolyte B”).
(1) The solid ³¹ P-NMR spectrum of the solid electrolyte has peaks due to crystals at 90.9 ± 0.4 ppm and 86.5 ± 0.4 ppm.
(2) The ratio (Xc) of crystals that give rise to the peak of (1) in the solid electrolyte is 60 mol% to 100 mol%.

The two peaks of condition (1) are observed when a high ion conductive crystal component is present in the solid electrolyte. Specifically, a peak due to P ₂ S ₇ ^4- and PS ₄ ^3- in the crystal.

Condition (2) defines the ratio Xc of the crystal in the solid electrolyte.
When a high ion conductive crystal component is present in a predetermined amount or more, specifically 60 mol% or more in the solid electrolyte, lithium ions move mainly through the high ion conductive crystal. Therefore, the non-crystalline portion in the solid electrolyte (glass portion) and a crystal lattice that does not exhibit high ionic conductivity (e.g., P ₂ S ₆ ^4-) than when moving, thereby improving lithium ion conductivity. The ratio Xc is preferably 65 mol% to 100 mol%.
The crystal ratio Xc can be controlled by adjusting the heat treatment time and temperature of the sulfide glass as a raw material.
The solid ³¹ P-NMR spectrum can be measured, for example, using a JNM-CMXP302 NMR apparatus manufactured by JEOL Ltd., with an observation nucleus of ³¹ P, an observation frequency of 121.339 MHz, a measurement temperature of room temperature, and a measurement method. Performed as MAS method.

The method for measuring the ratio Xc is to calculate a resonance line observed at 70 to 120 ppm into a Gaussian curve using a nonlinear least square method and calculate from the area ratio of each curve for the solid ³¹ P-NMR spectrum. For details, refer to Japanese Patent Application No. 2005-356889.

In the solid electrolyte of the present invention, the spin-lattice relaxation time T _1Li at room temperature (25 ° C.) measured by a solid-state ⁷ LiNMR method is preferably 400 ms or less. Relaxation time T _1Li becomes a molecular mobility of indicators in the solid electrolyte in comprising a glass state or a crystalline state and a glass state, molecular mobility is high and T _1Li short. Accordingly, since lithium ions are easily diffused during discharge, ion conductivity is increased. In the present invention, as described above, since a high ion conductive crystal component is contained in a predetermined amount or more, T _1Li can be 400 ms or less. T _1Li is preferably 350 ms or less.

The solid electrolyte of the present invention is, for example, a heat treatment of sulfide glass containing each element of lithium (Li), phosphorus (P) and sulfur (S) at a temperature of 190 ° C. or higher and 220 ° C. or lower for 3 to 240 hours, or It can be produced by heat treatment at a temperature higher than 220 ° C. and not higher than 340 ° C. for 0.1 to 240 hours.
As the raw material for sulfide glass, for example, Li ₂ S and P ₂ S ₅ can be used as in the case of the solid electrolyte A.

As Li ₂ S, those commercially available without particular limitation can be used, but those having high purity are preferred. For example, the Li ₂ S obtained by reacting lithium hydroxide with hydrogen sulfide in an aprotic organic solvent, an organic solvent, those purified by washing with 100 ° C. or higher temperature can be preferably used.
Specifically, in the manufacturing method disclosed in Japanese Patent Laid-Open No. 7-330312, it is preferable to produce Li ₂ S, it is obtained by purification of the Li ₂ S by the method described in International Publication WO2005 / No. 40039 preferable.

Since this Li ₂ S manufacturing method can obtain high-purity lithium sulfide by simple means, the raw material cost of sulfide glass can be reduced. In addition, the above purification method is economically advantageous because it can remove sulfur oxide, lithium N-methylaminobutyrate (hereinafter referred to as LMAB), and the like, which are impurities contained in Li ₂ S, by a simple treatment. .
Incidentally, the total amount of sulfur oxides contained in the Li ₂ S, preferably 0.15 mass% or less, LMAB is preferably not more than 0.1 mass%.

P ₂ S ₅ can be used without particular limitation as long as it is industrially manufactured and sold. In place of P ₂ S ₅ , elemental phosphorus (P) and elemental sulfur (S) in a corresponding molar ratio can also be used. Simple phosphorus (P) and simple sulfur (S) can be used without particular limitation as long as they are industrially produced and sold.

The mixing ratio of the raw materials is not particularly limited and may be appropriately adjusted, but is preferably about Li ₂ S: P ₂ S ₅ = 7: 3 (molar ratio).

Examples of the method for producing the sulfide glass include a melt quenching method and a mechanical milling method (hereinafter sometimes referred to as MM method).
Specifically, in the case of the melt quenching method, a predetermined amount of P ₂ S ₅ and Li ₂ S mixed in a mortar is put into a carbon-coated quartz tube and vacuum sealed. After reacting at a predetermined reaction temperature, the glass is put into ice and quenched to obtain a sulfide glass.
The reaction temperature at this time is preferably 400 ° C to 1000 ° C, more preferably 800 ° C to 900 ° C.
Moreover, reaction time becomes like this. Preferably it is 0.1 to 12 hours, More preferably, it is 1 to 12 hours.

In the case of the MM method, sulfide glass is obtained by mixing a predetermined amount of P ₂ S ₅ and Li ₂ S in a mortar and reacting them for a predetermined time by a mechanical milling method.
In the MM method, it is preferable to use a ball mill. Specifically, it is preferable to use a planetary ball mill. In the planetary ball mill, since the base plate revolves while the pot rotates, very high impact energy can be generated efficiently.
As conditions for the MM method, for example, when a planetary ball mill is used, the rotational speed may be set to several tens to several hundreds of revolutions / minute, and the treatment may be performed for 0.5 hours to 100 hours.
Although specific examples of the sulfide glass by the melt quenching method and the MM method have been described above, manufacturing conditions such as temperature conditions and processing time can be appropriately adjusted according to the equipment used.

Thereafter, the obtained sulfide glass is heat-treated at a predetermined temperature to produce the solid electrolyte of the present invention.
The heat treatment temperature for generating the solid electrolyte is preferably 190 ° C to 340 ° C, more preferably 195 ° C to 335 ° C, and particularly preferably 200 ° C to 330 ° C.
When the temperature is lower than 190 ° C., it may be difficult to obtain a crystal with high ion conductivity. When the temperature is higher than 340 ° C., a crystal with low ion conductivity may be generated.
In the case of a temperature of 190 ° C. or higher and 220 ° C. or lower, the heat treatment time is preferably 3 to 240 hours, particularly preferably 4 to 230 hours. Moreover, in the case of the temperature higher than 220 degreeC and 340 degrees C or less, 0.1 to 240 hours are preferable, 0.2 to 235 hours are especially preferable, Furthermore, 0.3 to 230 hours are preferable.
If the heat treatment time is shorter than 0.1 hour, a crystal having high ion conductivity may be difficult to obtain, and if it is longer than 240 hours, a crystal having low ion conductivity may be generated.

The solid electrolyte of the present invention is a nonflammable inorganic solid having a decomposition voltage of at least 10 V or more. Further, while maintaining the property that the lithium ion transport number is 1, it exhibits extremely high lithium ion conductivity of 10 ⁻³ S / cm level at room temperature. Therefore, it is extremely suitable as a material for a solid electrolyte of a lithium battery. Moreover, it is a solid electrolyte excellent in heat resistance.

The all-solid-state battery according to the present invention includes an electrolyte layer, a positive electrode, and a negative electrode, and has a current collector as necessary.
The electrolyte layer can be manufactured, for example, by forming a film of the above-described particulate lithium ion conductive solid material by a blast method or an aerosol deposition method. Also, a lithium ion conductive solid material can be formed by a cold spray method, a sputtering method, a vapor deposition method (CVD), a thermal spraying method, or the like.
Further, there is a method in which a solution in which a solid electrolyte is mixed with a solvent and a binder (such as a binder and a polymer compound) is applied and applied, and then the solvent is removed to form a film. Also, the solid electrolyte itself, solid electrolyte and binder (binder, polymer compound, etc.) and support (materials and compounds to reinforce the strength of the solid electrolyte layer and prevent short circuit of the solid electrolyte itself) are mixed -It is also possible to form a film by pressing the combined electrolyte under pressure.
The blasting method and the aerosol deposition method described above are preferable because a film can be formed in a temperature range that does not change the state of the solid electrolyte under a simple apparatus and room temperature conditions.
The thickness of the electrolyte layer is preferably in the range of 1 to 500 μm, more preferably 1 to 50 μm, and particularly preferably 1 to 30 μm.

  In the present invention, the current collector is a plate or foil made of copper, magnesium, stainless steel, titanium, iron, cobalt, nickel, zinc, aluminum, germanium, indium, lithium, or an alloy thereof. Can be used.

In a solid electrode material (electrode material) that is a member of an all-solid battery, in order to improve ion conductivity in addition to electron conductivity, the particles of the electrode material are in close contact with each other, and the junction points and surfaces between the particles are determined. It is important to ensure that there are many ion conduction paths. Therefore, for example, a method of mixing an ion conductive active material such as an electrolyte to obtain an electrode material is used. Further, the smaller the space generated in the gaps between the polar material particles (the ratio of the volume of the polar material particles to the volume of the polar material particles: the porosity), the denser the polar material layer is and the higher the ionic conductivity.
The electrode of the present invention can be produced by forming the electrode material (positive electrode material or negative electrode material) in a film shape on at least a part of the current collector. Examples of the film forming method include a blast method, an aerosol deposition method, a cold spray method, a sputtering method, a vapor deposition method, and a thermal spray method, as in the production of the battery member described above. By forming a film by such a method, the porosity of the electrode material layer can be further reduced, and the ionic conductivity can be improved.
In addition, the electrode layer can be manufactured by other similar methods described in the method for manufacturing the solid electrolyte layer.
The blasting method and the aerosol deposition method are preferred because a film can be formed in a temperature range that does not change the crystal state of the electrolyte under a simple apparatus and room temperature conditions.

As a positive electrode material, what is used as a positive electrode active material in the battery field | area can be used. For example, the sulfide, titanium sulfide (TiS _2), molybdenum sulfide (MoS _2), iron sulfide (FeS, FeS _2), copper sulfide (CuS) and nickel sulfide (Ni ₃ S ₂₎ or the like can be used.
In the oxide system, bismuth oxide (Bi ₂ O ₃ ), bismuth leadate (Bi ₂ Pb ₂ O ₅ ), copper oxide (CuO), vanadium oxide (V ₆ O ₁₃ ), lithium cobaltate (LiCoO ₂ ) Lithium nickelate (LiNiO ₂ ), lithium manganate (LiMnO ₂ ), or niobium selenide (NbSe ₃ ) can be used. It is also possible to use a mixture of these. Of these, lithium cobaltate is preferred.

  Further, as a conductive aid, a substance having electrical conductivity for allowing electrons to move smoothly in the positive electrode active material may be added as appropriate. The electrically conductive substance is not particularly limited, but a conductive substance such as acetylene black, carbon black and carbon nanotube or a conductive polymer such as polyaniline, polyacetylene and polypyrrole may be used alone or in combination. Can be used.

As a negative electrode material, what is used as a negative electrode active material in the battery field | area can be used. For example, carbon materials, specifically artificial graphite, graphite carbon fiber, resin-fired carbon, pyrolytic vapor-grown carbon, coke, mesocarbon microbeads (MCMB), furfuryl alcohol resin-fired carbon, polyacene, pitch-based carbon Examples include fibers, vapor grown carbon fibers, natural graphite, and non-graphitizable carbon. Or it may be a mixture thereof. Preferably, it is artificial graphite.
In addition, metallic lithium, metallic indium, metallic aluminum, metallic silicon, or an alloy combined with these metals themselves, other elements, or compounds can be used as the negative electrode material.
Furthermore, you may mix and use the solid electrolyte material used for an electrolyte layer with an pole material.

The all-solid-state battery of the present invention can be produced by bonding and joining the above-described battery members and / or electrode members of the present invention. As a method of joining, there are a method of laminating each member, pressurizing and pressure bonding, a method of pressing through two rolls (roll to roll), and the like.
Moreover, you may join to the joining surface through the active material which has ion conductivity, and the adhesive material which does not inhibit ion conductivity.
In joining, heat fusion may be performed as long as the crystal structure of the solid electrolyte does not change.

  The all-solid-state battery of the present invention operates as a battery without causing side reactions even when the electrolyte and the electrode agent are contacted or mixed and exposed to high temperatures. Moreover, the energy density is high, and safety, charge / discharge cycle characteristics, and long-term stability are excellent. Furthermore, since the battery of the present invention can be thinned, it can be stacked to obtain a high output and can be highly integrated.

The all solid state battery of the present invention can be covered with an exterior material such as a resin. Moreover, what coat | covered with the adsorbent and / or the alkaline substance containing material further to the exterior body which consists of a thermoplastic resin or a thermosetting resin as an exterior material can be used. The solid battery of the present invention contains a sulfur compound that may react with water to generate hydrogen sulfide in the solid electrolyte. Even if the all solid battery is destroyed for some reason, The adsorbent or the alkaline substance-containing material can be captured and detoxified.
Moreover, it can replace with coat | cover with an alkaline substance containing material, and can also make an exterior body itself contain an alkaline substance.

  In addition, the all solid state battery of the present invention includes a support plate having a plurality of through holes on the side of the positive electrode and the negative electrode that do not face the solid electrolyte layer, and the support plate is connected via the corresponding through hole of each support plate. It is preferable that a pressure of 1.5 to 200 MPa is applied to the all solid state battery element by tightening. By applying pressure in this way, it is possible to apply uniform pressure to the entire surface of the solid electrolyte layer, to suppress battery swelling at the center of the battery, and against repeated charge and discharge. Battery characteristics can be maintained.

Example 1
(1) Preparation of solid electrolyte 0.651 g (1.42 × 10 ⁻² mol) of high-purity lithium sulfide (made by Idemitsu Kosan Co., Ltd., purity: 99.9%) and 1 phosphorous pentasulfide (made by Aldrich) .349 g (6.07 × 10 ⁻³ mol) was mixed well, and these powders were put into an alumina pot and completely sealed.
The pot was attached to a planetary ball mill and mechanical milling was performed. At this time, milling was performed at a low speed (85 rpm) for the first few minutes in order to sufficiently mix the starting materials. Thereafter, the rotational speed was gradually increased and mechanical milling was performed at 370 rpm for 20 hours.
As a result of evaluating the obtained powder by X-ray measurement, it was confirmed that it was vitrified (sulfide glass).

The obtained sulfide glass was heat-treated at 330 ° C. for 1 hour to form a glass ceramic, thereby producing a solid electrolyte.
When the ionic conductivity of this solid electrolyte was measured by the alternating current impedance method (measurement frequency: 100 Hz to 15 MHz), it showed 5.0 × 10 ⁻³ S / cm at room temperature.
As a result of measuring ³¹ P-NMR of the solid electrolyte, the crystal ratio Xc was 85 mol%, the relaxation time T _1Li was 240 ms, and _peaks were observed at 90.9 ± 0.4 ppm and 86.5 ± 0.4 ppm. Existed.
The solid electrolyte was processed into a pellet-shaped (diameter of about 10 mm, thickness of about 1 mm).
When the ion conductivity of this molded body was measured by an alternating current impedance method (measurement frequency: 100 Hz to 15 MHz), it showed 4.5 × 10 ⁻³ S / cm at room temperature. The crystallinity measured by ³¹ P-NMR was 78 mol%.

(2) Production of positive electrode material The glass ceramic solid electrolyte produced in (1) above and lithium cobalt oxide as the positive electrode active material are mixed at a mass ratio of 5: 8 (solid electrolyte: lithium cobalt oxide), and the positive electrode material is produced. It was.

(3) Production of negative electrode material The glass ceramic solid electrolyte produced in (1) above and carbon graphite as the negative electrode active material were mixed at a mass ratio of 1: 1 (solid electrolyte: carbon graphite) to obtain a negative electrode material. .

(4) Manufacture of unit 2 Unit 2 shown in FIG. 1 was manufactured using an aerosol deposition apparatus (AD apparatus, manufactured by Iwata Nano Giken). Specifically, the positive electrode material produced in (2) above was sprayed onto a 5 × 5 × 1 mm stainless steel (SUS) plate (current collector 11) to form a 200 μm positive electrode layer. Further, the solid electrolyte produced in the above (1) was sprayed thereon to form a 20 μm solid electrolyte layer.

(5) Manufacture of unit 1 Unit 1 shown in Drawing 1 was manufactured using AD equipment. Specifically, the negative electrode material produced in (3) above was sprayed on one side of a 5 × 5 × 1 mm stainless steel (SUS) plate (current collector 11) to form a 200 μm negative electrode layer. did. Further, the solid electrolyte produced in the above (1) was sprayed thereon to form a 20 μm solid electrolyte layer.

(6) Manufacture of a solid battery element Each of the units 1 and 2 was hollowed out a 20 mmφ circular laminate. Disperse 0.1 mg of the solid electrolyte produced in the above (1) between the circular units 1 and 2, and apply a pressure of 981 MPa (10 tons / cm ² ) by a pressure press machine to obtain a solid battery element. Manufactured.

(7) Production of all-solid-state battery Five solid-state battery elements produced in the above (6) were connected in series (unit 3). Two units 3 were connected in series and sandwiched between two acrylic plates (support plate 21) having a thickness of 5 mm. (In FIG. 2, the two are shown in series for convenience.) As shown in FIG. 3, the acrylic plate is provided with five through holes 22, and a connecting jig 23 composed of bolts, nuts, and washers is provided. The wrench was used and tightened so that the pressure on the surface where the acrylic plate and the battery were in contact was 1.96 MPa (20 kg / cm ² ). In addition, the pressure of the surface where an acrylic board and a battery contact was measured with the pressure sensitive test paper 33 previously inserted between them.
The two solid battery elements were wired by electrode terminals 29 joined by welding. In addition, a protective coating was partially applied with polypropylene resin (28 in FIG. 2).

(8) Sealing with Resin (Exterior Material) The solid battery 20 produced in the above (7) was covered with a resin (exterior body 24) as shown in FIG. The coating with the resin (exterior body 24) was performed using the apparatus shown in FIG. That is, the all-solid-state battery 20 was loaded in a resin sealing mold 30, and a polybutadiene resin (“Epol” manufactured by Idemitsu Kosan Co., Ltd.) as a molten resin P was injected into the cavity 31. After cooling and curing the butadiene resin, the mold was removed and the solid battery sealed with the resin was taken out.

(9) Coating with Alkaline Substance-Containing Material As shown in FIG. 2, the solid battery sealed with the resin manufactured in (8) is sealed with a resin (exterior body 24) in a resin outer case 26. The stopped solid battery 20 was installed, and the entire periphery of the battery was covered with magnesium hydroxide beads 25 having a diameter of 2 mm to produce an all-solid battery for a vehicle according to the present invention. In addition, the electrode terminal 27 was joined to the electrode terminal 29, and the portion 28 in contact with the magnesium hydroxide beads 25 was covered with a polypropylene resin.
The all-solid-state battery had an initial charge / discharge efficiency of 84% and an operating potential of 28.5V.

  The solid state battery of the present invention is a high-performance secondary battery that has no liquid junction, has high heat resistance and high safety, and can maintain battery characteristics against repeated charge and discharge. Therefore, it is optimal as a battery for home appliances such as a portable information terminal, a portable electronic device, and a personal computer.

It is a schematic diagram which shows the structure of the solid battery element of this invention. 1 is a schematic diagram illustrating a configuration of a solid state battery of Example 1. FIG. It is the perspective view which looked at the all-solid-state battery of this invention from the electrode side. It is a schematic diagram which shows the apparatus which coat | covers a solid battery element with resin.

Explanation of symbols

1: Unit 1
2: Unit 2
3: Unit 3
11: current collector 12: negative electrode 13: solid electrolyte 14: positive electrode 20: solid battery element 21: support plate 22: through hole 23: connecting jig 24: exterior body (resin)
25: Magnesium hydroxide beads 26: Exterior case 27: Electrode terminal 28: Part in contact with magnesium hydroxide beads 29: Electrode terminal 30: Resin sealing mold 31: Cavity 32: Pressurizing jig 33: Pressure-sensitive test paper

Claims (6)

  An all-solid-state battery for home appliances, comprising a plurality of all-solid-state battery elements having a solid electrolyte layer interposed between a positive electrode and a negative electrode and having an operating potential of 30 V or less.   The solid electrolyte contains lithium element, phosphorus element and sulfur element, and in X-ray diffraction (CuKα: λ = 1.5418４), 2θ = 17.8 ± 0.3 deg, 18.2 ± 0.3 deg, 19. Has diffraction peaks at 8 ± 0.3 deg, 21.8 ± 0.3 deg, 23.8 ± 0.3 deg, 25.9 ± 0.3 deg, 29.5 ± 0.3 deg, 30.0 ± 0.3 deg The all-solid-state battery for household appliances of Claim 1 which is a lithium ion conductive sulfide type crystallized glass. The solid electrolyte contains elemental lithium, elemental phosphorus and elemental sulfur, and the solid ³¹ P-NMR spectrum of the solid electrolyte is caused by crystals at the positions of 90.9 ± 0.4 ppm and 86.5 ± 0.4 ppm. The all-solid-state battery for household appliances of Claim 1 which has the peak which carries out and the ratio of the said crystal | crystallization occupied to the said solid electrolyte is 60-100 mol%.   The sheath according to any one of claims 1 to 3, wherein the sheath is covered with a sheathing material, and the sheathing material is further coated with an adsorbent and / or an alkaline substance-containing material, the sheathing body made of a thermoplastic resin or a thermosetting resin. All-solid-state battery for home appliances.   All for household appliances in any one of Claims 1-4 which are coat | covered with exterior material, this exterior material consists of a thermoplastic resin or a thermosetting resin, and this exterior material contains an adsorbent and / or an alkaline substance. Solid battery.   An all-solid-state battery element comprising a support plate having a plurality of through holes on the side of the positive electrode and the negative electrode that do not face the solid electrolyte layer, and connecting and tightening the support plates through the corresponding through holes of each support plate The all-solid-state battery for household appliances in any one of Claims 1-5 to which the pressure of 1.5-200 Mpa is applied to.

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