JP5724952B2 - Sulfide solid state battery and manufacturing method thereof - Google Patents

Description

  The present invention relates to a sulfide solid state battery and a method for manufacturing the same.

  Conventionally, a non-aqueous electrolyte secondary battery using a sealed battery container and its manufacture have been known as a sulfide solid battery and a method for manufacturing the same, and Patent Document 1 discloses that the sealed battery container is inactive. It is described that gas is enclosed.

JP 7-226232 A

However, in the nonaqueous electrolyte secondary battery using the sealed battery container of Patent Document 1, the pressure for filling the inert gas is 0.5 kg / cm ² or less, and the nonaqueous electrolyte secondary battery is externally supplied. It has a structure that allows water to easily enter the battery.

  Here, the sulfide solid state battery among the non-aqueous electrolyte secondary batteries may have a reduced ionic conductivity when in contact with moisture. In addition, when the sulfide solid battery is in contact with moisture, hydrogen sulfide is generated, which may deteriorate the active material. These problems may reduce the output of the sulfide solid state battery.

  SUMMARY OF THE INVENTION In order to solve the above problems, an object of the present invention is to provide a sulfide solid state battery and a method for manufacturing the same that can suppress the ingress of gas containing water or moisture from the outside.

  The present invention includes a sulfide solid electrolyte, a sealing member that seals the positive electrode and the negative electrode, and a housing member that houses the sealing member. An inert gas is sealed inside the sealing member, and the inside of the sealing member A sulfide solid state battery is provided in which the pressure is higher than the pressure between the housing member and the sealing member.

  In the sulfide solid state battery of the present invention, the sealing member seals the sulfide solid electrolyte, the positive electrode, and the negative electrode, and the housing member houses the sealing member. Here, the inside of the sealing member is filled with an inert gas, and the pressure inside the sealing member is higher than the pressure between the housing member and the sealing member, which is the pressure outside the sealing member. For this reason, in the sulfide solid state battery of the present invention, it is possible to suppress the intrusion of gas containing water or moisture into the sealing member.

  The present invention further includes a sealing step of sealing the sulfide solid electrolyte, the positive electrode, and the negative electrode with a sealing member, and a housing step of housing the sealing member in the housing member, and the pressure inside the sealing member is the housing member. Provided is a method for manufacturing a sulfide solid state battery in which an inert gas is sealed inside a sealing member in a sealing step so as to be higher than the pressure between the sealing member and the sealing member.

  A method for manufacturing a sulfide solid state battery of the present invention includes the sealing step and the housing step, and sealing is performed in the sealing step so that the pressure inside the sealing member is higher than the pressure between the housing member and the sealing member. An inert gas is sealed inside the member. Thereby, it becomes possible to manufacture a sulfide solid state battery in which intrusion of water or a gas containing moisture into the sealing member is suppressed.

  ADVANTAGE OF THE INVENTION According to this invention, the sulfide solid state battery which can suppress permeation of the gas containing the water or the water | moisture from the outside, and its manufacturing method can be provided.

It is sectional drawing of the sulfide solid state battery of 1st embodiment. It is typical sectional drawing which shows the sealing part of the sealing member of the sulfide solid state battery of 2nd embodiment. It is the image which expanded the sealing part of the sealing member of the sulfide solid state battery of 2nd embodiment.

  Embodiments of the present invention will be described below. In the description of the drawings, the same reference numerals are used for the same elements, and duplicate descriptions are omitted.

(First embodiment)
The sulfide solid state battery 10 of the first embodiment includes a sealing member 7 that seals the sulfide solid electrolyte 3, the positive electrode 1, and the negative electrode 2, and a housing member 8 that houses the sealing member 7. Is filled with an inert gas. The pressure inside the sealing member 7 is higher than the pressure in the region between the housing member 8 and the sealing member 7.

  FIG. 1 is a cross-sectional view of a sulfide solid state battery 10 of the first embodiment. As shown in FIG. 1, the battery main body in the sulfide solid state battery 10 is accommodated in the sealing member 7. Here, the battery main body is formed by laminating a plurality of cells including a positive electrode 1, a negative electrode 2, and a sulfide solid electrolyte 3 sandwiched between the two electrodes, and a current collecting member 4 is disposed between the cells. . Further, the plurality of current collecting members are connected to the wiring member 5.

Sulfide solid electrolyte 3 is not limited in particular as long as it is a substance which sulfide or sulfide is blended containing sulfur can be used free machine compounds or Ranaru materials, general all-solid What is used for a battery can be used.

  The positive electrode 1 is formed on one surface of the solid electrolyte 3. The negative electrode 2 is formed on the surface of the solid electrolyte 3 where the positive electrode 1 described above is not formed. The electrode active material used for forming the positive electrode 1 and the negative electrode 2 (the positive electrode forming material and the negative electrode forming material) is the same as that used for the positive electrode and the negative electrode in a general all solid state battery. For example, at least an electrode active material (a positive electrode active material or a negative electrode active material) is included, and a Li ion conductivity improving material and a conductive material can be further included as necessary.

  If the sealing member 7 is a member which can seal a battery main-body part inside, it will not be restrict | limited in particular. For example, the sealing member 7 is preferably a moisture-proof multilayer film having a metal foil layer made of a metal foil capable of enhancing airtightness on the outside and a heat-sealing layer containing a thermoplastic resin on the inside. The metal foil layer can suppress moisture permeation to the battery body, and the heat-sealing layer can provide excellent strength.

  The material of the metal foil is not particularly limited as long as it is lightweight, flexible and chemically stable, but aluminum that is advantageous in terms of physical properties and cost can be preferably used. As the thermoplastic resin, polyamide resin such as nylon, polyethylene terephthalate, vinyl acetate resin, acrylic resin, epoxy resin, or polyolefin resin such as polyethylene or polypropylene can be used.

  Although the sealing member 7 seals the battery main body, the sealing member 7 may have a gap such as a gap because the inert gas 6 is sealed.

  The accommodating member 8 is not particularly limited as long as it is a member that can accommodate the sealing member 7 in which the battery main body is sealed, and for example, a member similar to the sealing member 7 can be used.

  The sulfide solid state battery 10 has a double structure in which the sealing member 7 is accommodated in the accommodating member 8, and the inert gas 6 is enclosed in the sealing member 7. For this reason, the pressure inside the sealing member 7 is higher than the pressure outside the sealing member 7, that is, the pressure between the housing member 8 and the sealing member 7. Thereby, it is possible to prevent water or a gas containing moisture from entering the sealing member 7.

  In the present embodiment, the inert gas 6 is not particularly limited as long as it is an inert gas, and argon gas, nitrogen gas, or the like can be used. For example, when argon gas (purity 99.99%) is used as the inert gas 6, the pressure of the inert gas 6 is preferably 90 to 110 kPa. When the pressure of the inert gas 6 is lower than 90 kPa, it is difficult to make the pressure inside the sealing member 7 higher than the pressure outside even if the inert gas 6 is sealed. Moreover, when the pressure of the inert gas 6 becomes higher than 110 kPa, the pressure in the sealing member 7 becomes high and it becomes difficult to seal.

  The inert gas 6 is preferably an inert gas having a water dew point of −70 ° C. or less (water content of 1 ppm or less). When the moisture dew point is −70 ° C. or lower, deterioration due to a small amount of moisture contained in the inert gas 6 is suppressed.

  The sulfide solid state battery 10 can be obtained by a method for manufacturing a sulfide solid state battery including a sealing step and a housing step.

  First, the sealing process will be described. In the sealing step, the battery body including the sulfide solid electrolyte 3, the positive electrode 1, and the negative electrode 2 is sealed with the sealing member 7. Here, the inert gas 6 is sealed inside the sealing member 7 so that the pressure inside the sealing member 7 becomes higher than the pressure in the region between the housing member 8 and the sealing member 7.

  As such means, for example, the battery main body is sealed with the sealing member 7, the sealing part as the end is slightly opened, and the hose of the cylinder filled with the inert gas 6 is used as the opening of the sealing part. The inert gas 6 may be enclosed and sealed in the sealing member 7 and sealed. Alternatively, the battery body may be sealed with the sealing member 7 in a chamber filled with the inert gas 6, so that the inert gas 6 is sealed in the sealing member 7.

  In the housing step, the sealing member 7 that seals the battery body is housed in the housing member 8. Since the pressure in the region between the housing member 8 and the sealing member 7 is lower than the pressure inside the sealing member 7, the pressure in the housing environment is not particularly limited, and may be, for example, under atmospheric pressure (101.3 kPa). .

  As described above, according to the sulfide solid state battery 10 of the first embodiment, the inert gas 6 is sealed inside the sealing member 7, and the pressure inside the sealing member 7 is determined by the accommodating member 8, the sealing member 7, and the like. Therefore, it is possible to suppress the intrusion of gas containing water or moisture from the outside.

(Second embodiment)
In the sulfide solid state battery 10 ′ (not shown) of the second embodiment, the sealing portion of the sealing member 7 contains a hygroscopic material.

  FIG. 2 is a schematic cross-sectional view showing a sealing portion of the sealing member 7 of the sulfide solid state battery 10 ′ of the second embodiment. As shown in FIG. 2, the sealing part of the sealing member 7 is formed by integrating the sealing member 7 including the sealing outer layer 7a and the sealing inner layer 7b, and the hygroscopic material is formed in the sealing inner layer 7b. 9 is contained in a dispersed manner.

  The sealing outer layer 7a is not particularly limited as long as it is sealed in the end region of the sealing member 7, and is preferably the above-described metal foil layer. Further, the thickness of the sealing outer layer 7a is not particularly limited, but is preferably about 50 μm, for example.

  The sealing inner layer 7 b is not particularly limited as long as it is sealed at the end region of the sealing member 7, and may be any material that can contain the hygroscopic material 9. The sealing inner layer 7b is preferably a heat-sealing layer containing the above-described thermoplastic resin, and a resin such as polypropylene is preferably used. The thickness of the sealing inner layer 7b is not particularly limited, but is preferably about 40 μm, for example.

  The hygroscopic material 9 is not particularly limited as long as it is a member that can absorb moisture, and for example, zeolite powder can be used. Further, the particle diameter of the hygroscopic material 9 is not particularly limited, but if it is about 3 to 10 μm, it is easily dispersed in the sealed inner layer 7b.

  In such a sealing portion, the hygroscopic material 9 is disposed on one sealing inner layer 7b, the other sealing inner layer 7b is disposed thereon, and heat or pressure is applied to seal the sealing portion. The stop inner layer 7b is fluidized, and the hygroscopic material 9 can be dispersed and integrated in the sealed inner layer 7b.

  FIG. 3 is an enlarged image of the sealing portion of the sealing member 7 of the sulfide solid state battery 10 ′ of the second embodiment. The sealing part uses aluminum core material (50 μm) as the sealing outer layer 7 a, polypropylene (40 μm) as the sealing inner layer 7 b, and zeolite powder (3 to 10 μm) as the hygroscopic material 9. Here, as hot pressure sealing conditions, the temperature was 160 ° C., the pressure was 5 MPa, and the heat and pressure application time was 30 seconds.

  As shown in FIG. 3, the sealing portion of the sealing member 7 obtained under the above conditions contains the zeolite powder as the hygroscopic material 9 dispersed and contained in the polypropylene as the sealing inner layer 7 b. confirmed.

  As described above, according to the sulfide solid state battery 10 ′ of the second embodiment, the sealing portion of the sealing member 7 includes the sealing outer layer 7a and the sealing inner layer 7b, and the sealing inner layer 7b includes Since the hygroscopic material 9 is contained in a dispersed manner, it is possible to suppress the ingress of gas containing water or moisture from the outside.

  In addition, embodiment mentioned above demonstrated embodiment of the sulfide solid battery which concerns on this invention, and its manufacturing method, The sulfide solid battery which concerns on this invention, and its manufacturing method are what was described in this embodiment. It is not limited.

  For example, in the above description, the sulfide solid state battery of the first embodiment and the second embodiment has been described separately, but the battery having both technical features, that is, the inert gas 6 is contained in the sealing member 7. The pressure inside the sealing member 7 is higher than the pressure between the housing member 8 and the sealing member 7, and the sealing portion of the sealing member 7 includes the sealing outer layer 7 a and the sealing inner side. The sulfide solid state battery including the layer 7b and containing the hygroscopic material 9 dispersed in the sealed inner layer 7b is a preferable form because it can further suppress the intrusion of gas containing water or moisture.

  DESCRIPTION OF SYMBOLS 1 ... Positive electrode, 2 ... Negative electrode, 3 ... Sulfide solid electrolyte, 4 ... Current collection member, 5 ... Wiring member, 6 ... Inert gas, 7 ... Sealing member, 7a ... Sealing outer layer, 7b ... Sealing inner layer , 8 ... housing member, 9 ... hygroscopic material, 10 ... sulfide solid state battery.

Claims (2)

A sealing member for sealing the sulfide solid electrolyte, the positive electrode and the negative electrode;
A housing member for housing the sealing member,
An inert gas is sealed inside the sealing member,
The pressure inside the sealing member is higher than the pressure between the housing member and the sealing member;
Sulfide solid state battery. A sealing step of sealing the sulfide solid electrolyte, the positive electrode and the negative electrode with a sealing member;
A housing step of housing the sealing member in a housing member,
An inert gas is sealed inside the sealing member in the sealing step so that the pressure inside the sealing member is higher than the pressure between the housing member and the sealing member.
A method for producing a sulfide solid state battery.