JP2022156220A - Sulfide all-solid-state battery - Google Patents

Abstract

To provide a manufacturing method of a sulfide all-solid-state battery with improved productivity.SOLUTION: A sulfide all-solid-state battery includes an electrode body 20 having a sulfide solid electrolyte, an exterior body 11 that houses the electrode body 20, and a pressurizing member 12 disposed between the electrode body 20 and the exterior body 11 and made of a material that expands without generating gas when heated. According to the present disclosure, even the sulfide all-solid-state battery can obtain a pressurizing force by heating after being sealed in the exterior body 11, such that the pressurizing member 12 can be efficiently arranged and productivity can be improved.SELECTED DRAWING: Figure 3

Description

The present disclosure relates to sulfide all-solid-state batteries.

An all-solid-state battery includes a positive electrode including a positive electrode active material layer, a negative electrode including a negative electrode active material layer, and a solid electrolyte layer including a solid electrolyte disposed therebetween, and such layers are repeatedly laminated. form an electrode body, and this electrode body is hermetically sealed in the exterior body.

Patent Document 1 discloses a pressurizing spacer containing microcapsules as a means for holding the electrode body in the outer package while being pressurized in the stacking direction. It is configured.

JP-A-8-83624

When the microcapsules described in Patent Document 1 are used, gas is generated from inside the microcapsules when the microcapsules are thermally expanded. Therefore, the electrode body and the pressure spacer are placed in the outer package, and the outer package is not sealed. It is necessary to deaerate including the gas generated by thermal expansion in the container and then seal it. However, when sulfide is used as the solid electrolyte of an all-solid-state battery (sulfide-all-solid-state battery), a low-humidity environment is required to process without sealing the exterior body to suppress the reaction of sulfide, which reduces productivity. do. Even if the treatment is possible, it would require an increase in the size of the equipment and time to reduce the humidity to a low level before starting the equipment.
Therefore, an object of the present disclosure is to provide a sulfide all-solid-state battery capable of efficiently arranging a pressure member and improving productivity.

As one means for solving the above problems, the present disclosure provides an electrode body having a sulfide solid electrolyte, an exterior body that accommodates the electrode body, and an electrode body that is disposed between the electrode body and the exterior body, and is heated to generate a gas. a pressurizing member obtained from a material that expands without causing a

According to the present disclosure, even in a sulfide all-solid-state battery, it is possible to obtain a pressurizing force by heating after being sealed in the exterior body, so that it is possible to efficiently arrange the pressurizing member and improve productivity. can be done.

FIG. 1 is a diagram schematically showing the appearance of an all-solid-state battery 10. As shown in FIG. FIG. 2 is a diagram showing one cross section of the all-solid-state battery 10. As shown in FIG. FIG. 3 is a diagram showing another cross section of the all-solid-state battery 10. As shown in FIG. FIG. 4 is a diagram for explaining the layer structure of the unit electrode body 21. As shown in FIG. FIG. 5 is a diagram for explaining the state of the first pressurizing member 12 when it is compressed. FIG. 6 is a diagram for explaining the state of the first pressure member 12 when inflated. 7A and 7B are diagrams for explaining the states of compression and expansion of the second pressure member 12. FIG. 8A and 8B are diagrams for explaining the states of compression and expansion of the third pressure member 12. FIG. 9A and 9B are diagrams for explaining the manufacturing of the all-solid-state battery 10. FIG. 10A and 10B are diagrams for explaining the production of the all-solid-state battery 10. FIG.

1. 1. All-Solid-State Battery FIG. 1 is an external perspective view schematically showing an all-solid-state battery 10 according to one embodiment. 2 is a cross-sectional view of the cylindrical all-solid-state battery 10 along the circumferential direction, and FIG. 3 is a cross-sectional view of the cylindrical all-solid-state battery 10 along the cylinder axis. It should be noted that the all-solid-state battery 10 described here is a schematic one, and includes members normally provided in addition to those described here. For example, an all-solid-state battery normally has a terminal (not shown) on the outside, but it is omitted here.

As can be seen from FIGS. 1 to 3, the all-solid-state battery 10 in this embodiment includes an exterior body 11, an electrode body 20, and a pressure member 12. As shown in FIG. Each component will be described below.

1.1. Exterior Body The exterior body 11 is a member that encloses the electrode body 20 and the pressure member 12 of the all-solid-state battery 10 to form an exterior. The exterior body 11 of this embodiment has a cylindrical shape with a bottom, and the electrode body 20 and the pressure member 12 are accommodated in the cylinder to be in a sealed state. The shape of the exterior body 11 is not particularly limited and can be applied according to the shape of the electrode body 20 to be housed.
The material forming the exterior body 11 is not particularly limited, but for example, it can be made of stainless steel and can be shaped like a can (armored can).

1.2. electrode body 20
The electrode body 20 is a power storage member, and is formed by stacking a plurality of unit electrode bodies 21 . In this embodiment, the plurality of unit electrode bodies 21 are stacked in the direction along the axis of the cylindrical exterior body 11 .
FIG. 4 schematically shows the configuration of the unit electrode body 21. As shown in FIG. As can be seen from FIG. 4 , the unit electrode body 21 includes a positive electrode active material layer 22 containing a positive electrode active material, a negative electrode active material layer 23 containing a negative electrode active material, and a layer between the positive electrode active material layer 22 and the negative electrode active material layer 23 . It has a solid electrolyte layer 24 formed therebetween, a positive electrode current collector layer 25 that collects current from the positive electrode active material layer 22 , and a negative electrode current collector layer 26 that collects current from the negative electrode active material layer 23 .

[Positive electrode active material layer]
The positive electrode active material layer 22 is a layer containing a positive electrode active material, and if necessary, may further contain at least one of a solid electrolyte material, a conductive material and a binder.
A known active material may be used as the positive electrode active material. For example, cobalt _- based (LiCoO2, etc.), nickel _- based ( _LiNiO2 , etc.), manganese _- based ₍ LiMn2O4, _{Li2Mn2O3 ,} etc.), iron phosphate _- based _{( LiFePO4} , _Li2FeP2O7 , etc.) ), NCA series (nickel, cobalt and aluminum compounds), NMC series (nickel, manganese and cobalt compounds) and the like. More specifically, there are LiNi _1/3 Co _1/3 Mn _1/3 O ₂ and the like.
The surface of the positive electrode active material may be coated with an oxide layer such as a lithium niobate layer, a lithium titanate layer, or a lithium phosphate layer.

In this embodiment, the solid electrolyte is a sulfide solid electrolyte. This is because problems arise when the solid electrolyte is a sulfide as described above.
Examples of sulfide solid electrolyte materials having Li ion conductivity include Li ₂ SP ₂ S ₅ , Li ₂ SP ₂ S ₅ -LiI, Li ₂ SP ₂ S ₅ -Li ₂ O, Li _{2SP2S5 -} Li2O _- LiI, _{Li2S - SiS2} , _{Li2S -} SiS2 _- LiI, Li2S _- SiS2 _- LiBr, Li2S _- SiS2 _- LiCl, Li2 S—SiS ₂ —B ₂ S ₃ —LiI, Li ₂ S—SiS ₂ —P ₂ S ₅ —LiI, Li ₂ S—B ₂ S ₃ , Li ₂ SP ₂ S ₅ —ZmSn (where m, n is a positive number, and Z is one of Ge, Zn, and Ga.), Li ₂ S—GeS ₂ , Li ₂ S—SiS ₂ —Li ₃ PO ₄ , Li ₂ S—SiS ₂ —LixMOy (where x and y are positive numbers, and M is any one of P, Si, Ge, B, Al, Ga, and In.). The above description of "Li ₂ SP _{2 S 5 " means a sulfide solid electrolyte material using a raw material composition containing Li 2 S and P 2 S 5 , and} the same applies to other descriptions. be.

The binder is not particularly limited as long as it is chemically and electrically stable. Examples include rubber-based binders such as butadiene rubber (SBR), olefin-based binders such as polypropylene (PP) and polyethylene (PE), and cellulose-based binders such as carboxymethylcellulose (CMC).
As the conductive material, carbon materials such as acetylene black (AB), ketjen black, and carbon fiber, and metal materials such as nickel, aluminum, and stainless steel can be used.

The content of each component in the positive electrode active material layer 22 and the shape of the positive electrode active material layer 11 may be the same as conventional ones. In particular, the sheet-like positive electrode active material layer 22 is preferable from the viewpoint that the all-solid-state battery 10 can be easily constructed. In this case, the thickness of the positive electrode active material layer 22 is, for example, preferably 0.1 μm or more and 1 mm or less, and more preferably 1 μm or more and 150 μm or less.

[Negative electrode active material layer]
The negative electrode active material layer 23 is a layer containing at least a negative electrode active material. A binding material, a conductive material, and a solid electrolyte material may be included as necessary. The binder, conductive material, and solid electrolyte material can be considered in the same manner as the positive electrode active material layer 22 .

The negative electrode active material is not particularly limited, but when forming a lithium ion battery, the negative electrode active material may be carbon materials such as graphite or hard carbon, various oxides such as lithium titanate, Si or Si alloys, Alternatively, metallic lithium, lithium alloys, and the like can be mentioned.

The content and shape of each component in the negative electrode active material layer 23 may be the same as conventional ones. In particular, the sheet-like negative electrode active material layer 23 is preferable from the viewpoint that the all-solid-state battery 10 can be easily configured. In this case, the thickness of the negative electrode active material layer 23 is, for example, preferably 0.1 μm or more and 1 mm or less, and more preferably 1 μm or more and 150 μm or less.

[Solid electrolyte layer]
The solid electrolyte layer 24 is a layer containing a solid electrolyte arranged between the positive electrode active material layer 22 and the negative electrode active material layer 23 . Solid electrolyte layer 24 contains at least a sulfide solid electrolyte material. As the solid electrolyte material, the same sulfide solid electrolyte material as described for the positive electrode active material layer 22 can be considered.

[Current collector layer]
The current collectors are a positive electrode current collector layer 25 that collects current for the positive electrode active material layer 22 and a negative electrode current collector layer 26 that collects current for the negative electrode active material layer 23 . Examples of materials that constitute the positive electrode current collector layer 25 include stainless steel, aluminum, nickel, iron, titanium, and carbon. On the other hand, examples of materials forming the negative electrode current collector layer 26 include stainless steel, copper, nickel, and carbon.

1.3. Pressing Member The pressing member 12 is arranged inside the exterior body 11 so as to bury the inner surface of the exterior body 11 and the outer surface of the electrode body 20 . As a result, each layer constituting the electrode body 20 is pressurized, and a strong contact between the layers can be maintained.
The pressure member 12 is made of a thermally expandable material, expands when heated, and does not generate gas when heated. The pressure member 12 is in a state after being expanded in the state where the all-solid-state battery 10 is formed. Specific examples of the pressing member 12 will be described below.

[First aspect]
5 and 6 are diagrams for explaining the expansion of the pressure member 12 according to the first mode. 5 is before expansion, FIG. 6 is after expansion, and the main expansion direction is the horizontal direction of the paper surface.
The pressure member 12 according to the first aspect includes a main body 12a that is elastically deformable like a sponge and has numerous minute cavities 12b, and a binding material 12c made of resin whose binding strength is reduced by heating. have.
The pressure member 12 according to the first aspect is compressed so as to prevent expansion in the expansion direction as shown in FIG. . This maintains the compressed state. On the other hand, when the pressure member 12 according to the first mode is heated from the state of FIG. The pressure member 12 expands. At this time, since no gas is generated by heating, the material can be heated and expanded in a closed space.
Examples of the material forming the main body 12a include a sponge-like member made of glass fiber (glass sponge, glass wool), a material made of ceramic fiber (rock wool), and the like.
On the other hand, examples of materials constituting the binder 12c include resins (ethylene vinyl acetate, olefin) and the like.

[Second aspect]
FIG. 7 shows a diagram for explaining the expansion of the pressure member 12 according to the second aspect. The drawing on the left side of FIG. 7 is before expansion, and the drawing on the right side of FIG. 7 is after expansion.
The pressure member 12 according to the second aspect has a fiber group formed by entangling countless fibers 12d and a binding material 12e made of resin whose binding strength is reduced by heating.
In the pressurizing member 12 according to the second aspect, before expansion, as shown in the left side of FIG. 7, the pressure member 12 is compressed so as to prevent expansion in the expansion direction, and the fibers 12d approaching each other are bound by the binding material 12e. worn and held. This maintains the compressed state. On the other hand, when the pressure member 12 according to the second mode is heated from the state shown on the left side of FIG. The pressure member 12 expands as shown in the right side of FIG. At this time, since no gas is generated by heating, the material can be heated and expanded in a closed space.

[Third aspect]
FIG. 8 shows a diagram for explaining the expansion of the pressure member 12 according to the third aspect. The drawing on the left side of FIG. 8 is before expansion, and the drawing on the right side of FIG. 8 is after expansion.
The pressing member 12 according to the third aspect has a corrugated sheet material 12f made of a shape memory alloy.
In the pressure member 12 according to the third aspect, the corrugated plate is deformed so that the height of the corrugated plate is H1 so as to prevent expansion in the expansion direction as shown in the left side of FIG. 8 before expansion. . This maintains the compressed state. On the other hand, when the pressure member 12 according to the third mode is heated from the state shown on the left side of FIG. The pressurizing member 12 expands as shown in the drawing on the right side of . At this time, since no gas is generated by heating, the material can be heated and expanded in a closed space.

2. Manufacturing method of all-solid-state battery The all-solid-state battery 10 as described above can be manufactured as follows.
First, as shown in FIG. 9, the electrode body 20 and the pressure member 12 before expansion are accommodated inside the exterior body 11 before sealing. Although the order of storage is not particularly limited, for example, the pressurizing member 12 that has been deformed into a cylindrical shape and has not been inflated is stored along the inner peripheral surface inside the exterior body 11, and the cylindrical pressurizing member 12 is stored. This can be done by arranging the electrode body 20 inside the member 12 .

Thereafter, as shown in FIG. 10, the exterior body 11 is sealed and heated. Due to this heating, the pressure member 12 expands as described above, and the pressure member 12 fills the internal space of the exterior body 11 and presses the electrode body 20 as shown in FIGS.

3. Effect etc. According to the all-solid-state battery of the present disclosure, since the pressurizing member that does not generate gas by heating is applied as described above, even if it is a sulfide all-solid-state battery, it is heated after being sealed in the exterior body. Since the pressurizing force can be obtained by arranging the pressurizing member efficiently, the productivity can be improved.

10 All-solid-state battery 11 Exterior body 12 Pressure member 20 Electrode body 21 Unit electrode body

Claims (1)

an electrode body having a sulfide solid electrolyte;
an exterior body that houses the electrode body;
a pressurizing member disposed between the electrode body and the exterior body and made of a material that expands without generating gas when heated;
All-solid battery.

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