JP2017126422A - Method for manufacturing all-solid battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing an all-solid battery, by which the displacement of a battery element can be suppressed.SOLUTION: A method for manufacturing an all-solid battery in which a battery element arranged by laminating positive and negative electrodes each having a collecting tab part in part thereof, and a solid electrolyte layer to be disposed between the positive and negative electrodes is sealed in an outer packaging body comprises the steps of: disposing the outer packaging body so as to cover the battery element and welding the collecting tab parts with the outer packaging body to form an unwelded part in at least part of the outer packaging body except parts in contact with the collecting tab parts of the outer packaging body; initially charging the battery element under an oxygen-containing gas atmosphere after the unwelded part-forming step; and welding the unwelded part of the outer packaging body to seal the battery element by the outer packaging body after the initially charging step.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for manufacturing an all-solid battery.

In the field of all-solid-state batteries, there have been attempts to improve the performance of all-solid-state batteries by paying attention to battery charge / discharge.
For example, Patent Document 1 discloses a sulfide all solid state battery that performs charging and discharging in an argon gas atmosphere.

JP 2014-143133 A JP 2014-086209 A

In the production of an all-solid-state battery, it is conceivable to provide a first charging step in a specific gas atmosphere (in an oxygen atmosphere) in order to improve battery performance. However, in the case of a battery that needs to be sealed, such as a laminated laminate battery, it is necessary to perform the initial charging step before the sealing, but if the initial charging is performed in the state before sealing, the position of each layer There is a problem that deviation occurs.
The present invention has been accomplished in view of the above circumstances, and an object of the present invention is to provide a method for manufacturing an all-solid battery capable of suppressing displacement of battery elements.

The method for producing an all-solid battery according to the present invention includes a battery element in which a positive electrode and a negative electrode having a current collecting tab portion at least in part, and a solid electrolyte layer disposed between the positive electrode and the negative electrode are stacked. In the method for producing an all-solid battery sealed with
The exterior body is disposed so as to cover the battery element, the current collecting tab portion and the exterior body are welded, and at least part of the exterior body other than the portion in contact with the current collection tab portion is not welded Forming a part;
After the unwelded portion forming step, the step of charging the battery element for the first time in an oxygen-containing gas atmosphere;
After the initial charging step, a step of welding an unwelded portion of the outer package and sealing the battery element with the outer package is provided.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the all-solid-state battery which can suppress the position shift of a battery element can be provided.

It is a schematic diagram which shows an example of the all-solid-state battery at the time of the first charge process in the manufacturing method of this invention. It is a cross-sectional schematic diagram which shows an example of the all-solid-state battery at the time of the first charge process in the manufacturing method of this invention. It is a schematic diagram which shows an example of the conventional all-solid-state battery. It is a cross-sectional schematic diagram which shows an example of the conventional all-solid-state battery.

The method for producing an all-solid battery according to the present invention includes a battery element in which a positive electrode and a negative electrode having a current collecting tab portion at least in part, and a solid electrolyte layer disposed between the positive electrode and the negative electrode are stacked. In the method for producing an all-solid battery sealed with
The exterior body is disposed so as to cover the battery element, the current collecting tab portion and the exterior body are welded, and at least part of the exterior body other than the portion in contact with the current collection tab portion is not welded Forming a part;
After the unwelded portion forming step, the step of charging the battery element for the first time in an oxygen-containing gas atmosphere;
After the initial charging step, a step of welding an unwelded portion of the outer package and sealing the battery element with the outer package is provided.

FIG. 3 is a schematic view showing an example of a conventional all-solid battery.
As shown in FIG. 3, the all solid state battery 300 includes a positive electrode 2, a negative electrode 3, a positive electrode 2, and a negative electrode 3 having a solid electrolyte layer (not shown) stacked thereon. The negative electrode 3 is provided with a negative electrode current collecting tab portion 5. The positive electrode current collecting tab portion 4 and the negative electrode current collecting tab portion 5 are connected to the external terminal 7.

FIG. 4 is a schematic cross-sectional view showing an example of a conventional all-solid battery.
As shown in FIG. 4, the all-solid battery 400 includes a restraint plate 8, a negative electrode current collector (negative electrode current collection tab portion 5), a negative electrode 3, a solid electrolyte layer 9, a positive electrode 2, and a positive electrode collection in order from the lower side in the vertical direction. An electric body (positive electrode current collecting tab portion 4) and a constraining plate 8 are laminated.

Since the conventional all solid state battery as shown in FIGS. 3 and 4 is easy to touch the oxygen environment, the battery can be efficiently contacted with oxygen.
However, since there is no exterior body, there is a problem that foreign matters are easily mixed from the outside.
Moreover, since it is not restrained when charging, there exists a problem that the position shift of a battery element tends to arise.

FIG. 1 is a schematic diagram showing an example of an all solid state battery during an initial charging step in the production method of the present invention.
As shown in FIG. 1, an all-solid battery 100 includes a laminated outer package 1 in which a positive electrode 2, a negative electrode 3, a positive electrode 2, and a negative electrode 3 are laminated with a solid electrolyte layer (not shown). Is provided with a positive electrode current collecting tab portion 4, a negative electrode 3 is provided with a negative electrode current collecting tab portion 5, and a contact portion between the end portions of the positive electrode current collecting tab portion 4 and the negative electrode current collecting tab portion 5 and the outer package 1 is provided. It welds and the welding part 6 is formed. The positive electrode current collecting tab portion 4 and the negative electrode current collecting tab portion 5 are connected to the external terminal 7.

FIG. 2 is a schematic cross-sectional view showing an example of an all solid state battery during the initial charging step in the production method of the present invention.
As shown in FIG. 2, the all-solid-state battery 200 includes, in order from the lower side in the vertical direction, the restraint plate 8, the exterior body 1, the negative electrode current collector (negative electrode current collection tab portion 5), the negative electrode 3, the solid electrolyte layer 9, and the positive electrode. 2. A positive electrode current collector (positive electrode current collection tab portion 4), an outer package 1, and a restraint plate 8 are laminated.

The inventors of the present invention have found that after only the side where the current collecting tab of the battery element is present is welded to the exterior body, the initial charge is performed with at least a part of the other side being released.
Thereby, since the current collection tab part is welded with the exterior body, the position shift of a battery element can be suppressed.
In addition, foreign substances can be prevented from being mixed during the initial charge in an oxygen-containing gas atmosphere in order to improve battery performance.
Furthermore, the risk that the restraint plate or the like directly contacts the battery while maintaining a state in which it is easy to touch the oxygen environment is reduced.

  The manufacturing method of the all-solid-state battery of this invention has at least (1) unwelded part formation process, (2) initial charge process, and (3) sealing process.

(1) Unwelded portion forming step In the unwelded portion forming step, the exterior body is disposed so as to cover the battery element, the current collecting tab portion and the exterior body are welded, and the current collecting tab portion of the exterior body is contacted. This is a step of forming an unwelded portion in at least a part other than the portion.
By forming the unwelded portion, the battery element can be exposed to an oxygen-containing gas atmosphere.
The battery element is formed by laminating a positive electrode and a negative electrode having a current collecting tab part at least in part, and a solid electrolyte layer disposed between the positive electrode and the negative electrode.

The positive electrode contains at least a positive electrode active material, and if necessary, contains a conductive material, a binder, and a solid electrolyte described later, and has a current collecting tab portion on at least a part of the positive electrode.
The position of the current collection tab part of a positive electrode will not be specifically limited if it is a position which can be connected with an external terminal.
Examples of the positive electrode current collector used as the current collecting tab portion of the positive electrode include metal materials such as SUS, Ni, Cr, Au, Pt, Al, Fe, Ti, and Zn.
A conventionally known material can be used as the positive electrode active material. When the all-solid battery is a lithium battery, for example, lithium cobaltate (LiCoO ₂ ), lithium nickelate (LiNiO ₂ ), Li _{1 + x} Ni _1/3 Mn _1/3 Co _1/3 O ₂ (0 ≦ x <0 .3), lithium manganate (LiMn ₂ O ₄ ), Li _{1 + x} Mn _2−xy M _y O ₄ (M is at least one selected from the group consisting of Al, Mg, Co, Fe, Ni, Zn) Element, Li—Mn spinel with different composition represented by 0 ≦ x <0.5, 0 ≦ y <2), lithium titanate, lithium metal phosphate (LiMPO ₄ , M = Fe, Mn, Co, Ni ) And the like.
The shape of the positive electrode active material is not particularly limited, and examples thereof include particles and plates.
The positive electrode active material preferably has a coating layer in which the surface of the positive electrode active material is coated with a solid electrolyte.
The method for coating the surface of the positive electrode active material with the solid electrolyte is not particularly limited. For example, a solid electrolyte such as LiNbO ₃ can be applied to the positive electrode active material in an atmospheric environment using a rolling fluid type coating apparatus (manufactured by POWREC, Inc.). Examples of the method include coating and firing in an atmospheric environment.
The solid electrolyte that forms the coating layer may be any material that has lithium ion conductivity, does not flow even when in contact with the active material or the solid electrolyte, and can maintain the shape of the coating layer. _{LiNbO 3, Li 4 Ti 5 O} 12, Li 3 PO 4 and the like.
The binder is not particularly limited, and examples thereof include butadiene rubber (BR), polyvinylidene fluoride (PVdF), and styrene / butadiene rubber (SBR).
The conductive material is not particularly limited, and examples thereof include acetylene black, ketjen black, and carbon fiber.

The method for producing the positive electrode is not particularly limited, and an example is shown below.
A 5% by mass butyl butyrate solution of butyl butyrate, PVdF binder (manufactured by Kureha Co., Ltd.) in a polypropylene (PP) container, a positive electrode active material coated with the solid electrolyte, and a sulfide solid electrolyte (Li ₂ containing LiBr and LiI) S-P ₂ S ₅ series glass ceramics) is added to the container, VGCF (trademark) (manufactured by Showa Denko KK) is added as a conductive material, and the mixture is stirred for 30 seconds with an ultrasonic dispersing device (SMT Co., Ltd. UH-50). .
Next, the container is shaken with a shaker (manufactured by Shibata Kagaku Co., Ltd., TTM-1) for 3 minutes, and further stirred with an ultrasonic dispersion device for 30 seconds.
After shaking for 3 minutes with a shaker, coating is performed on Al foil (manufactured by Nihon Foil Co., Ltd.) by the blade method using an applicator.
Then, the coated electrode is naturally dried.
Then, a positive electrode is obtained by making it dry for 30 minutes on a 100 degreeC hotplate.

The negative electrode contains at least a negative electrode active material, and if necessary, contains a conductive material, a binder, and a solid electrolyte described later, and has a current collecting tab portion in at least a part of the negative electrode.
The position of the current collection tab part of a negative electrode will not be specifically limited if it is a position which can be connected with an external terminal.
Examples of the negative electrode current collector used as the current collecting tab portion of the negative electrode include metal materials such as SUS, Cu, Ni, Fe, Ti, Co, and Zn.
Examples of the negative electrode active material include carbon materials such as graphite and hard carbon, Si and Si alloys, Li ₄ Ti ₅ O _{12 and the} like.
As the conductive material, the binder, and the solid electrolyte used for the negative electrode, the same materials as those used for the positive electrode described above can be used.

The method for producing the negative electrode is not particularly limited, and an example is shown below.
PP container with 5% butyl butyrate solution of butyl butyrate, PVdF binder (manufactured by Kureha Co., Ltd.), natural graphite carbon (Nippon Carbon Co., Ltd.) with an average particle size of 10 μm as a negative electrode active material, sulfide solid electrolyte as LiBr, added to the vessel to _Li 2 _S-P 2 _{S 5} -based glass ceramic containing LiI, stirred for 30 seconds with an ultrasonic dispersing device (manufactured by SMT Ltd. UH-50).
Next, the container is shaken for 30 minutes with a shaker (manufactured by Shibata Kagaku Co., Ltd., TTM-1).
It coats on Cu foil (made by Furukawa Electric Co., Ltd.) by a blade method using an applicator.
Then, the coated electrode is naturally dried.
Then, a negative electrode is obtained by drying for 30 minutes on a 100 degreeC hotplate.

  The average particle diameter of the particles in the present invention is calculated by a conventional method. An example of a method for calculating the average particle size of the particles is as follows. First, a transmission electron microscope (hereinafter referred to as TEM) with an appropriate magnification (for example, 50,000 to 1,000,000 times), an image or a scanning electron microscope (hereinafter referred to as SEM). In the image, for a certain particle, the particle diameter when the particle is regarded as spherical is calculated. Calculation of the particle size by such TEM observation or SEM observation is performed for 200 to 300 particles of the same type, and the average of these particles is taken as the average particle size.

The solid electrolyte layer contains at least a solid electrolyte, and may contain a binder or the like as necessary.
The solid electrolyte is not particularly limited as long as it has ion conductivity. For example, an oxide-based amorphous solid electrolyte such as Li ₂ O—B ₂ O ₃ —P ₂ O ₅ or Li ₂ O—SiO ₂ is used. _{, Li 2 S-SiS 2,} LiI-Li 2 S-SiS 2, LiI-Li 2 S-P 2 S 5, LiI-Li 2 S-P 2 O 5, LiI-Li 3 PO 4 -P 2 S 5 Sulfide-based amorphous solid electrolyte such as Li ₂ S—P ₂ S ₅ , LiI, Li ₃ N, Li ₅ La ₃ Ta ₂ O ₁₂ , Li ₇ La ₃ Zr ₂ O ₁₂ , Li ₆ BaLa ₂ Ta _{2 Examples} thereof include crystalline oxides and oxynitrides such as O ₁₂ , Li ₃ PO _{(4-3 / 2w)} N _w (w <1), and Li _3.6 Si _0.6 P _0.4 O ₄ .
The binder used for the solid electrolyte layer can be the same as that used for the positive electrode described above.

The manufacturing method of a solid electrolyte layer is not specifically limited, An example is shown below.
Heptane PP container made, butadiene rubber (BR) binder 5 wt% heptane solution of (JSR Co., Ltd.), _{Li 2 S-P} 2 containing LiBr and LiI as a sulfide-based solid electrolyte having an average particle diameter of 2.5μm It added S ₅ based glass ceramics, stirred for 30 seconds with an ultrasonic dispersing device (manufactured by SMT Ltd. UH-50).
Next, the container is shaken for 30 minutes with a shaker (manufactured by Shibata Kagaku Co., Ltd., TTM-1).
Then, it coats on Al foil with a blade method using an applicator.
After coating, dry naturally.
Then, a solid electrolyte layer is obtained by making it dry on a 100 degreeC hotplate for 30 minutes.

Although it does not specifically limit as a shape of an exterior body, A laminate type etc. can be mentioned.
The material of the exterior body is not particularly limited as long as it is stable to the electrolyte, and examples thereof include resins such as polypropylene, polyethylene, and acrylic resin.

(2) Initial charging step The initial charging step is a step of initially charging the battery element in an oxygen-containing gas atmosphere after the unwelded portion forming step. Thereby, the capacity maintenance rate of the all-solid-state battery can be improved.
The conditions for the initial charging are not particularly limited, and examples thereof include constant current and constant voltage charging.
Examples of the oxygen-containing gas include pure oxygen and air.

(3) Sealing process The sealing process is a process of sealing the battery element with the exterior body by welding the unwelded portion of the exterior body after the initial charging process.
The welding method is not particularly limited, and a conventionally known method can be used. In the case of a laminate type battery, thermocompression bonding and the like can be mentioned.

  Examples of the all solid state battery obtained by the production method of the present invention include a lithium battery, a sodium battery, a magnesium battery, and a calcium battery. Among these, a lithium battery is preferable.

DESCRIPTION OF SYMBOLS 1 Exterior body 2 Positive electrode 3 Negative electrode 4 Positive electrode current collection tab part (positive electrode current collector)
5 Negative electrode current collector tab (negative electrode current collector)
6 welding part 7 external terminal 8 restraint plate 9 solid electrolyte layer 100 all solid state battery 200 all solid state battery 300 all solid state battery 400 all solid state battery

Claims (1)

In a method for producing an all-solid battery in which a battery element in which a positive electrode and a negative electrode having a current collecting tab portion at least in part and a solid electrolyte layer disposed between the positive electrode and the negative electrode is laminated is sealed with an outer package. ,
The exterior body is disposed so as to cover the battery element, the current collecting tab portion and the exterior body are welded, and at least part of the exterior body other than the portion in contact with the current collection tab portion is not welded Forming a part;
After the unwelded portion forming step, the step of charging the battery element for the first time in an oxygen-containing gas atmosphere;
And a step of welding an unwelded portion of the outer package and sealing the battery element with the outer package after the initial charging step.