WO2012029641A1

WO2012029641A1 - Solid state battery and manufacturing method for same

Info

Publication number: WO2012029641A1
Application number: PCT/JP2011/069254
Authority: WO
Inventors: 倍太尾内; 充吉岡; 剛司林; 邦雄西田; 渡辺　浩一
Original assignee: 株式会社村田製作所
Priority date: 2010-09-01
Filing date: 2011-08-26
Publication date: 2012-03-08

Abstract

Provided are a solid state battery manufacturing method in which moisture taken into a solid state battery during the solid state battery manufacturing steps can be removed in order to reduce the possibility of internal pressure rising within a housing or other exterior member; and a solid state battery manufactured by the same. In the solid state battery manufacturing method a laminate is produced by stacking a positive electrode green sheet, a solid electrolyte green sheet and a negative electrode green sheet. Next, a sintered body is formed by sintering the laminate, and the moisture contained in the sintered body is removed.

Description

Solid battery and manufacturing method thereof

The present invention generally relates to a solid battery and a manufacturing method thereof, and more particularly, to a solid battery in which a laminated positive electrode layer, a solid electrolyte layer, and a negative electrode layer are joined by sintering, and a manufacturing method thereof.

In recent years, batteries, particularly secondary batteries, have been used as main power sources for portable electronic devices such as mobile phones and portable personal computers, backup power sources, and hybrid vehicle (HEV) power sources. Among secondary batteries, a lithium ion secondary battery having a high energy density and capable of being charged and discharged is used.

In such a lithium ion secondary battery, an organic electrolyte (electrolytic solution) in which a lithium salt is dissolved in a carbonate ester, an ether organic solvent or the like has been conventionally used as a medium for moving ions.

However, there is a risk that the electrolyte solution leaks in the lithium ion secondary battery having the above configuration. Moreover, the organic solvent etc. which are used for electrolyte solution are combustible substances. For this reason, it is required to further increase the safety of the battery.

Therefore, in order to increase the safety of the lithium ion secondary battery, it has been proposed to use a solid electrolyte as the electrolyte instead of the organic solvent electrolyte, and an all-solid secondary battery in which all the constituent elements are made of solid. Development is underway.

For example, JP 2007-258148 A (hereinafter referred to as Patent Document 1) discloses a positive electrode containing a positive electrode active material, a negative electrode containing a negative electrode active material, and an internal electrode having a solid electrolyte layer containing a solid electrolyte. An all-solid battery with a body is disclosed. The positive electrode active material, the negative electrode active material, and the solid electrolyte are all phosphoric acid compounds. The internal electrode body is integrated by firing the positive electrode, the negative electrode, and the solid electrolyte layer. The internal electrode body contains moisture.

JP 2008-243560 A (hereinafter referred to as Patent Document 2) discloses a laminate of a positive electrode, a negative electrode, and an electrolyte layer containing a phosphoric acid compound in at least one of a positive electrode active material, a negative electrode active material, and a solid electrolyte. A method for producing an all-solid-state secondary battery is disclosed in which a body is energized (charged) in the presence of moderate moisture.

JP 2007-258148 A JP 2008-243560 A

In the solid state battery described in Patent Document 1, the power generation element, which is an internal electrode body, positively contains moisture, and in the solid state battery disclosed in Patent Document 2, the power generation is a laminate of a positive electrode, a negative electrode, and an electrolyte layer. A method is disclosed in which the internal resistance of a solid state battery is reduced by energizing the element after containing moisture.

The moisture content of the solid battery of Patent Document 1 is 0.3 to 10% by mass, and the moisture content of the solid battery of Patent Document 2 is 0.5 to 3% by mass. These moisture contents are extremely high compared to the moisture contained in the raw materials, or the amount of moisture taken into the battery when the electrode is manufactured or incorporated into the battery, so the power generation element is stored in the battery housing. By energizing the power generation element after sealing the battery casing, moisture may be decomposed and the internal pressure inside the battery casing may increase. On the other hand, when the power generation element is energized without sealing the battery housing, the above internal pressure does not increase. However, since it is necessary to perform the sealing work in a low humidity atmosphere so that moisture is not taken into the power generation element after energization, the manufacturing cost may increase.

Accordingly, an object of the present invention is to remove moisture taken into the solid battery during the manufacturing process of the solid battery so as to reduce the possibility that the internal pressure inside the exterior member such as the casing will increase. It is providing the manufacturing method of a solid battery, and the solid battery manufactured by the manufacturing method.

The method for manufacturing a solid battery according to the present invention includes the following steps.

(A) Lamination process for producing a laminate by laminating the green sheets of the positive electrode layer, the solid electrolyte layer, and the negative electrode layer.

(B) Sintering process in which the laminate is sintered to produce a sintered body

(C) Moisture removal step to remove moisture contained in the sintered body

In the method for producing a solid state battery of the present invention, it is preferable that the water removal step is performed in an initial charge step for charging the solid state battery for the first time.

In the method for producing a solid battery of the present invention, it is preferable that the moisture removal step is performed in an initial charging step in which the solid battery is charged for the first time after the sintered body is dried.

It is preferable that the initial charging step is performed by charging the solid state battery with a battery voltage of 1.3 V or more.

Moreover, it is preferable that the initial charging step is performed after the sintered body is sealed with the exterior member.

In the method for producing a solid state battery of the present invention, it is preferable that the moisture content of the sintered body before the moisture removing step is 0.1% by mass or more and 0.3% by mass or less.

Moreover, in the method for producing a solid battery of the present invention, it is preferable that the moisture content of the sintered body after the moisture removing step is 0.00001% by mass or more and 0.01% by mass or less.

Furthermore, in the method for producing a solid battery of the present invention, it is preferable that at least one of the positive electrode layer, the solid electrolyte layer, and the negative electrode layer includes a solid electrolyte having a composition of NASICON structure.

Furthermore, in the method for producing a solid battery of the present invention, it is preferable that at least one of the positive electrode layer and the negative electrode layer contains a lithium-containing phosphate compound as an electrode active material.

The solid battery of the present invention is manufactured by the above-described manufacturing method.

According to the present invention, moisture taken into the power generation element in the manufacturing process of the power generation element including the positive electrode layer, the solid electrolyte layer, and the negative electrode layer is removed in advance in the moisture removal process after sintering. For this reason, even if the solid battery is used repeatedly, the decomposition of moisture does not occur, and the possibility that the internal pressure inside the exterior member increases can be reduced.

It is a top view which shows typically the external appearance of the all-solid-state secondary battery produced in the Example of this invention. It is sectional drawing which shows typically the cross section of the all-solid-state secondary battery seen from the direction of the II-II line | wire of FIG. It is a figure which shows the first charge curve of the all-solid-state secondary battery produced in the Example of this invention. It is a figure which shows the discharge curve of the all-solid-state secondary battery produced in the Example of this invention.

In the method for producing a solid battery of the present invention, first, a green body of each of the positive electrode layer, the solid electrolyte layer, and the negative electrode layer is laminated to produce a laminate. Thereafter, the laminate is sintered to produce a sintered body. And the water | moisture content contained in a sintered compact is removed. In this way, moisture taken into the power generation element in the manufacturing process of the power generation element including the positive electrode layer, the solid electrolyte layer, and the negative electrode layer is removed in advance in the moisture removal process after sintering. For this reason, even if charging / discharging is repeated, the decomposition of moisture does not occur, and the possibility that the internal pressure inside the exterior member increases can be reduced.

It is preferable that the water removal is performed in an initial charging process in which the solid battery is charged for the first time. In this case, moisture taken into the power generation element in the power generation element manufacturing process is removed in the initial charging process. At this time, it is estimated that water is electrochemically decomposed. Thereby, the same effect as the case where moisture is removed by previously drying the sintered body for a long time can be obtained. Therefore, it is not necessary to perform a step of drying the sintered body for a long time in order to remove moisture, so that the method for manufacturing a solid battery can be simplified.

The moisture removal may be performed in an initial charging process in which the solid battery is charged for the first time after the sintered body is dried. In this case, moisture taken into the power generation element in the power generation element manufacturing process can be more effectively removed.

Water decomposition usually occurs at about 1.2 V, but depending on the type of material constituting the solid battery, such as an electrode active material or a solid electrolyte, water decomposition occurs at a battery voltage lower than 1.2 V, or 1 Water decomposition may occur at battery voltages higher than 2V. Therefore, the initial charging step is preferably performed by charging the solid state battery with a battery voltage equal to or higher than the water decomposition voltage. It is preferable to carry out by charging the solid battery at a battery voltage of 1.3 V or higher. In this case, moisture taken into the power generation element in the power generation element manufacturing process can be more effectively removed. In addition, when charging the solid state battery with a battery voltage of 1.3 V or higher during the initial charging step, the moisture can be removed more effectively by providing a state where the battery is held at an arbitrary voltage of 1.3 V or higher for a certain period of time. Can do. In this case, it is preferable to hold at a battery voltage of 1.3V to 4.0V. More preferably, it is held at a battery voltage of 1.3 V or more and 3.0 V or less. In the initial charging process, when the voltage is held for a certain period of time, which is a battery voltage of 4.0 V or more, there is a possibility that the cycle characteristics and the like are deteriorated.

Moreover, it is preferable that the initial charging step is performed after the sintered body is sealed with an exterior member. In this case, since the sintered body is initially charged after being sealed with an exterior member such as a housing, the power generation element from which moisture has been removed by the initial charging step does not absorb moisture from the surrounding outside air. A solid battery can be manufactured.

In the method for producing a solid battery according to the present invention, the moisture content of the sintered body before the moisture removing step is preferably 0.1% by mass or more and 0.3% by mass or less (1000 ppm or more and 3000 ppm or less). . In this case, the moisture taken into the power generation element depends on the temperature and humidity of the environment in the power generation element manufacturing process, but is 0.1% by mass to 0.3% by mass with respect to the mass of the sintered body. Then, even when the power generation element is stored in an exterior member such as a housing and then the exterior member is sealed and the initial charging process is performed, the pressure inside the exterior member significantly increases through the initial charging process. Thus, moisture can be removed.

In the solid battery manufacturing method of the present invention, the moisture content of the sintered body after the moisture removal step is 0.00001 mass% or more and 0.01 mass% or less (0.1 ppm or more and 100 ppm or less). It can be reduced within the range.

Furthermore, in the method for producing a solid battery of the present invention, it is preferable that at least one of the positive electrode layer, the solid electrolyte layer, and the negative electrode layer includes a solid electrolyte having a composition of NASICON structure. In this case, high ion conductivity that is essential for the battery operation of the solid state battery can be obtained. In particular, it is preferable to use glass or glass ceramics having a composition of NASICON type structure as the solid electrolyte. In this case, a denser sintered body is likely to be obtained due to the viscous flow of the glass phase in the sintering process.

Furthermore, in the method for producing a solid battery of the present invention, it is preferable that at least one of the positive electrode layer and the negative electrode layer contains a lithium-containing phosphate compound as an electrode active material. In this case, the high temperature stability of the phosphoric acid skeleton makes it easy to suppress the phase change of the electrode active material or the reaction with the solid electrolyte in the sintering process, so that the capacity of the solid battery can be increased. it can. In particular, it is preferable to use a combination of an electrode active material containing a lithium-containing phosphate compound and a solid electrolyte having a NASICON type structure. In this case, it is possible to obtain good contact between the electrode active material and the solid electrolyte while suppressing the reaction in the sintering process.

For the solid electrolyte, it is possible to use a material that has ionic conductivity and is so small that electron conductivity is negligible. Examples of the solid electrolyte include lithium halide, lithium nitride, lithium oxyacid salt, and derivatives thereof. In addition, Li—PO compounds such as lithium phosphate (Li ₃ PO ₄ ), LIPON (LiPO _4−x N _x ) in which nitrogen is introduced into lithium phosphate, Li—Si— such as Li ₄ SiO ₄ O-based compounds, Li-P-Si-O based compounds, Li-V-Si-O based compounds, La _0.51 Li _0.35 TiO _2.94 , La _0.55 Li _0.35 TiO ₃ , Li _3x La _{2 / 3-x} TiO _3, etc. Examples thereof include compounds having a perovskite structure and compounds having a nasicon structure. As the solid electrolyte, it is more preferable to use a compound having a perovskite structure and a compound having a nasicon type structure, and it is particularly preferable to use a compound having a nasicon type structure.

The composition of the compound of the NASICON type _{_{_{structure, Li x M y (PO 4}}} ) 3 [ however, x = 1 ~ 2, y = 1 ~ 2, M = Ti, Ge, Al, Ga, at least one of Zr And a part of P may be substituted with B, Si, or the like. For example, Li _1.5 Al _0.5 Ge _1.5 (PO ₄ ) ₃ , Li _1.2 Al _0.2 Ti _1.8 (PO ₄ ) ₃ or the like can be used.

Examples of the solid electrolyte having a composition of NASICON structure include two or more having a composition of different NASICON structures such as Li _1.5 Al _0.5 Ge _1.5 (PO ₄ ) ₃ and Li _1.2 Al _0.2 Ti _1.8 (PO ₄ ) _3. A mixture in which the solid electrolyte is mixed may be used.

Further, as the solid electrolyte having a composition of NASICON structure, a solid electrolyte containing a crystal phase of NASICON structure or glass in which a crystal phase of NASICON structure is deposited by heat treatment may be used.

The kind of electrode active material is not particularly limited. As an electrode active material, a layered compound such as LiCoO ₂ , LiCo _1/3 Ni _1/3 Mn _1/3 O ₂ , a spinel structure such as LiMn ₂ O ₄ , LiNi _0.5 Mn _1.5 O ₄ , Li ₄ Ti ₅ O ₁₂ A phosphoric acid compound such as LiFePO ₄ or LiMnPO ₄ may be used as the compound having an olivine type structure, and a phosphoric acid compound such as Li ₃ V ₂ (PO ₄ ) ₃ may be used as the compound having a nasicon type structure.

The method for forming the green sheets of the positive electrode layer, the negative electrode layer, and the solid electrolyte layer is not particularly limited, and a die coater, a comma coater, screen printing, or the like can be used.

The slurry for forming the green sheets of the positive electrode layer, the negative electrode layer, and the solid electrolyte layer can be prepared by wet-mixing a polymer material, a positive electrode or negative electrode active material, and a solid electrolyte. Media can be used in wet mixing, and specifically, a ball mill method, a viscomill method, or the like can be used. On the other hand, a wet mixing method that does not use media may be used, and a sand mill method, a high-pressure homogenizer method, a kneader dispersion method, or the like can be used.

The slurry may contain a plasticizer. Although the kind of plasticizer is not particularly limited, phthalic acid esters such as dioctyl phthalate and diisononyl phthalate may be used.

The method for laminating the green sheets is not particularly limited, but a hot isostatic press (HIP), a cold isostatic press (CIP), a hydrostatic press (WIP), or the like can be used.

Next, specific examples of the present invention will be described. In addition, the Example shown below is an example and this invention is not limited to the following Example.

Hereinafter, examples of the method for producing a solid state battery of the present invention will be described.

(Green sheet production)

As the solid electrolyte powder, glass powder having a composition of Li _1.5 Al _0.5 Ge _1.5 (PO ₄ ) ₃ was used.

As the electrode active material powder, a powder having a crystal phase of Li ₃ V ₂ (PO ₄ ) ₃ was used.

The solid electrolyte powder as a main material, polyvinyl butyral resin, and alcohol were weighed to a weight ratio of 100: 15: 140. Polyvinyl butyral resin, solid electrolyte powder and alcohol were enclosed in a pot together with media and rotated on a pot rack, and then the media was taken out to produce a solid electrolyte slurry.

A mixed powder obtained by mixing 50 parts by weight of a solid electrolyte powder, 45 parts by weight of an electrode active material powder, and 5 parts by weight of carbon powder as a conductive agent in a mortar is used as a main material, and the main material, polyvinyl butyral resin, and alcohol are used. An electrode slurry was prepared in the same manner as the solid electrolyte slurry by weighing to a weight ratio of 100: 15: 140.

Using a doctor blade method, a solid electrolyte slurry was coated on a polyethylene terephthalate (PET) film, dried on a hot plate heated to a temperature of 40 ° C., and a solid electrolyte green sheet was prepared to a thickness of 50 μm. .

The electrode slurry was coated on a polyethylene terephthalate (PET) film using a doctor blade method and dried on a hot plate heated to a temperature of 40 ° C. to prepare an electrode green sheet having a thickness of 50 μm.

(Lamination process)

After the solid electrolyte green sheet was peeled from the PET film, four sheets of this solid electrolyte green sheet were laminated, and a solid electrolyte layer was formed by pressurizing and pressure bonding at a temperature of 60 ° C. After the electrode green sheet was peeled from the PET film, one electrode green sheet was laminated on one side of the solid electrolyte layer formed above, and the positive electrode layer was formed by pressurizing and pressing at 60 ° C. . Two electrode green sheets were laminated on the surface opposite to the solid electrolyte layer formed as described above by the same method as described above, and the negative electrode layer was formed by pressure bonding.

The obtained green sheet laminate was cut into a size of 10 mm × 10 mm to produce a laminate.

The reason why a plurality of the solid electrolyte green sheets are laminated is to provide sufficient mechanical strength to the sintered solid electrolyte layer to facilitate the handling of the solid electrolyte layer in the steps described later. There is no particular problem even if the solid electrolyte layer is formed with a single green sheet without laminating a plurality of solid electrolyte green sheets. The reason why the number of electrode green sheets used for forming the positive electrode layer and the number of electrode green sheets used for forming the negative electrode layer are different is that Li ₃ V ₂ (PO ₄ ) ₃ is used as the positive electrode active material. This is because the capacity per unit weight of Li ₃ V ₂ (PO ₄ ) ₃ differs between the case where Li ₃ V ₂ (PO ₄ ) ₃ is used as the negative electrode active material and about 2 times. is there. Each thickness of a positive electrode layer and a negative electrode layer can be suitably changed according to the material of the electrode active material to be used.

In addition, the laminate of the green sheets was cut to a predetermined size to produce a laminate, but the laminate may be produced by laminating green sheets that have been cut to a predetermined size in advance. The cutting method is not particularly limited, and a die or the like can be used.

(Sintering process)

The obtained laminate was fired at a temperature of 500 ° C. in an air atmosphere to remove the polyvinyl butyral resin, and then sintered at a temperature of 700 ° C. in a nitrogen gas atmosphere to prepare a sintered body. .

The sintering temperature and atmosphere can be appropriately changed according to the type of resin, solid electrolyte, and electrode active material used.

(Production of power generation elements)

In order to efficiently draw current from each of the positive electrode layer and the negative electrode layer, a platinum (Pt) layer is formed as a current collector layer by sputtering on the outer surface of each of the positive electrode layer and the negative electrode layer of the obtained sintered body. Then, eight power generation elements 1 to 8 having the same specifications were produced.

The material for the current collector layer is not particularly limited as long as it has electron conductivity, and the method for forming the current collector layer is not particularly limited. As the material having electron conductivity, metal, carbon, conductive oxide, or the like can be used. The current collector layer can be formed by applying or dipping a slurry of an electron conductive material on the outer surface of each of the positive electrode layer and the negative electrode layer in addition to vacuum deposition and chemical vapor deposition (CVD). Then, it may be formed by heat treatment.

The entire manufacturing process from (production of green sheet) to (production of power generation element) was performed in an environment where the temperature was 25 ° C. and the relative humidity was 50%.

(Production of solid battery and initial charging process)

(Production of solid state battery)

An aluminum laminate film was used for the casing as the exterior member of the solid battery.

The

power generation elements

1, 2, and 3 produced above were used without being particularly dried. Each of the

power generation elements

1 and 2 was surrounded by an aluminum laminate film 20 and sealed to produce

solid batteries

1 and 2 like the all-solid secondary battery 1 shown in FIG.

In the all-solid-state secondary battery 1 shown in FIG. 1, the power generation element 10 (FIG. 2) is housed inside an aluminum laminate film 20 as an exterior member and sealed with a sealing portion 21. As shown in FIGS. 1 and 2, the positive electrode terminal 11 and the negative electrode terminal 12 are drawn out from the inner side of the aluminum laminate film 20 through the sealing portion 21. By attaching a metal plate to each of the positive electrode side and the negative electrode side of the power generation element 10 and bonding a metal plate, and pulling out the end portion of the metal plate from the sealing portion 21 of the aluminum laminate film 20, A positive electrode terminal 11 and a negative electrode terminal 12 of the battery 1 were formed.

(Moisture removal process I: Initial charging process only)

The initial charging process was performed by scanning the

solid batteries

1 and 2 at a voltage of 0.1 mV / min from the open circuit voltage to 3V. At this time, it is considered that water is electrochemically decomposed and removed by holding the

solid state batteries

1 and 2 at a voltage of 1.3 V or higher, which is higher than 1.2 V which is the decomposition voltage of water.

(Moisture removal process II: drying process + initial charging process)

The power generation elements 4, 5, and 6 were dried at a temperature of 100 ° C. for 10 hours to remove a part of moisture contained in the power generation elements. The power generation elements 4 and 5 were sealed in the same manner as the

solid batteries

1 and 2 like the all-solid secondary battery 1 shown in FIG. Thereafter, the initial charging step was performed in the same manner as the

solid batteries

1 and 2 described above.

(Moisture-containing process + initial charge process)

The power generation elements 7 and 8 were used after being allowed to stand in an environment with a temperature of 30 ° C. and a relative humidity of 80% to contain moisture. The power generation element 7 was sealed like the all-solid secondary battery 1 shown in FIG. Thereafter, the initial charging step was performed in the same manner as the

solid batteries

1 and 2 described above.

(Measurement of initial charge curve)

FIG. 3 shows the initial charging curves of the solid batteries 1, 4 and 7 obtained in the initial charging step. In FIG. 3, the solid line indicates the initial charge curve of the solid battery 1, the one-dot chain line indicates the solid battery 4, and the two-dot chain line indicates the initial charge curve of the solid battery 7. As shown in FIG. 3, in the solid battery 1, a current peak that rises from around 1.2 V and is estimated to be caused by water decomposition was confirmed, but in the solid battery 4, such a current peak was confirmed. Was not. In addition, the initial charge curves of the solid battery 1 and the solid battery 4 are substantially the same except for the current peak rising from around 1.2 V, and it can be seen that the initial charge curve of the solid battery 4 is slightly superior to the solid battery 1.

In addition, in the initial charge curve of the solid battery 7, the current rose from around 0.5 V, and it was confirmed that the current was generally higher than that of the solid batteries 1 and 4. When the solid battery after the initial charging process was visually confirmed, in the solid battery 7, the swelling of the aluminum laminate film 20 due to the internal pressure increase, which was not confirmed before the initial charging process, was confirmed. This swelling is presumed to be due to gas generated by the decomposition of water. On the other hand, in the solid batteries 1 and 4, such a change in the aluminum laminate film 20 was not confirmed.

(Measurement of discharge capacity)

The discharge capacity was measured by discharging the solid batteries 1, 4 and 7 from the open circuit voltage to 0 V with a constant current of 2 μA.

Fig. 4 shows the discharge curves of the solid batteries 1, 4 and 7. In FIG. 4, the solid line indicates the solid battery 1, the one-dot chain line indicates the solid battery 4, and the two-dot chain line indicates the solid battery 7. As shown in FIG. 4, the shapes of the discharge curves of the solid batteries 1 and 4 are almost the same, and the discharge capacity of the solid battery 4 is slightly higher than that of the solid battery 1, but both the solid batteries 1 and 4 discharge about 40 μAh. It was confirmed that capacity was obtained. It was confirmed that the solid battery 7 can only obtain a capacity of about 25 μAh.

(Measurement of water content in power generation element)

The solid batteries 2 and 5 produced above were disassembled, and the power generation elements 2 and 5 were taken out from the aluminum laminate film 20.

The amount of water contained in the power generation elements 2 and 5 taken out after the initial charging step and the power generation elements 3, 6, and 8 produced above was measured. A trace moisture measuring device (CA200 manufactured by Mitsubishi Chemical Analytech Co., Ltd.) was used for the measurement.

Table 1 shows the results of moisture content measurement.

From Table 1, it was confirmed that the moisture content was reduced from 1315 ppm (power generation element 3) to 15 ppm (power generation element 2) when only the initial charging step was performed without drying. When the initial charging process was performed after drying in advance, the moisture content changed from 18 ppm (power generation element 6) after drying to 11 ppm (power generation element 5), confirming that the moisture content was further reduced. did. In addition, it was confirmed that the power generation element 8 positively containing moisture contains 5000 ppm or more moisture.

The disassembly of the solid battery and the water content measurement were promptly performed in an environment with a dew point of −60 ° C.

Therefore, in the method for manufacturing a solid battery according to the present invention, it is possible to reduce the possibility that the internal pressure inside the aluminum laminate film 20 will increase by removing the water taken into the power generation element in the manufacturing process of the solid battery. I understand. Moreover, as a moisture removal process of the present invention, when only the initial charging process is performed (power generation element 2), the power generation element is dried in advance and then the initial charging process is performed (power generation element 5). It can be seen that a moisture removal effect can be obtained.

In the above embodiment, the aluminum laminate film 20 is used as the exterior member, but the periphery of the power generation element is sealed with resin or sealed around the power generation element with an insulating paste. An exterior member such as a housing may be formed by covering with baking or the like and baking.

Moreover, the charging conditions in the initial charging process are not particularly limited. Charge to a specified voltage with a constant current, charge the battery while maintaining the battery voltage at a specified voltage, charge by changing the charging current or charging voltage stepwise, put a pause between charges, or The initial charging process can be performed by charging in combination.

It should be considered that the embodiments and examples disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is shown not by the above embodiments and examples but by the claims, and is intended to include all modifications and variations within the meaning and scope equivalent to the claims.

By energizing the power generation element after the power generation element is stored in an exterior member such as a housing and sealed, moisture decomposition does not occur, and the possibility that the internal pressure inside the exterior member rises can be reduced. A solid battery can be provided.

1: all-solid secondary battery, 10: power generation element, 11: positive electrode terminal, 12: negative electrode terminal, 20: aluminum laminate film, 21: sealing part.

Claims

A laminating step of laminating each green sheet of a positive electrode layer, a solid electrolyte layer, and a negative electrode layer to produce a laminate;
A sintering step of sintering the laminate to produce a sintered body;
A moisture removal step for removing moisture contained in the sintered body;
A method for producing a solid state battery.
The method for producing a solid state battery according to claim 1, wherein the moisture removing step comprises an initial charge step for charging the solid state battery for the first time.
The method for producing a solid battery according to claim 1 or 2, wherein the moisture removing step includes an initial charging step of drying the sintered body and then charging the solid battery for the first time.
The method for producing a solid state battery according to claim 2 or 3, wherein the initial charging step is performed by charging the solid state battery with a battery voltage of 1.3 V or more.
The method for producing a solid state battery according to any one of claims 2 to 4, wherein the initial charging step is performed after the sintered body is sealed with an exterior member.
The moisture content of the sintered body before the moisture removal step is performed is according to any one of claims 1 to 5, wherein the sintered body has a moisture content of 0.1 mass% or more and 0.3 mass% or less. A method for producing a solid state battery.
The moisture content of the sintered body after the moisture removing step is performed is any one of claims 1 to 6, wherein the moisture content is 0.00001 mass% or more and 0.01 mass% or less. Manufacturing method for a solid battery.
8. The manufacturing of a solid state battery according to claim 1, wherein at least one of the positive electrode layer, the solid electrolyte layer, and the negative electrode layer includes a solid electrolyte having a NASICON type composition. Method.
The method for producing a solid state battery according to any one of claims 1 to 8, wherein at least one of the positive electrode layer and the negative electrode layer contains a lithium-containing phosphate compound as an electrode active material.
A solid state battery manufactured by the method for manufacturing a solid state battery according to any one of claims 1 to 9.