JP6879230B2 - All solid state battery - Google Patents

Description

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

An all-solid-state battery such as an all-solid-state lithium-ion battery is attracting attention as a power source for driving an electric motor of a hybrid vehicle or the like. Such an all-solid-state battery is an all-solid-state battery having at least one unit all-solid-state battery having a positive electrode current collector layer, a positive electrode active material layer, a solid electrolyte layer, a negative electrode active material layer, and a negative electrode current collector layer in this order. It has a laminate. Various battery cases are used to enclose this all-solid-state battery laminate.

Patent Document 1 describes a battery including a battery cell and a container for accommodating the battery cell, and the container is a lower lid having a lower surface, a side surface erected from the lower surface, and an opening provided on the upper surface side. , And an upper lid having an upper surface, a side surface erected from the upper surface, and an opening provided on the lower surface side, and the side surface of the lower lid and the side surface of the upper lid are overlapped with each other, and the battery cell is housed in the container. A battery is disclosed, wherein the terminal connected to the container is fixed to a member which should form a side surface of the container.

Patent Document 2 describes a battery module including a battery and an exterior body accommodating the battery, and the battery has a positive electrode layer, a negative electrode layer, and an electrolyte disposed between the positive electrode layer and the negative electrode layer. A battery cell and a container capable of accommodating the battery cell are provided, and the container has a lower surface, a side surface standing from the lower surface and surrounding the lower surface, and an upper surface opening formed so that the battery cell to be accommodated can pass through. A lower lid having a first contact portion extending from the outer periphery of the upper surface opening and projecting from the side surface, and an upper lid having a second contact portion in contact with the first contact portion and closing the upper surface opening. The container is sealed by a close contact portion protruding from the side surface of the lower lid and the upper lid, in which the first contact portion and the second contact portion are brought into close contact with each other and fixed, and the outer body is provided with the close contact portion. A battery module is disclosed, which comprises a recess.

Patent Document 3 describes a coating layer in a lithium secondary battery using lithium or a lithium compound as a negative electrode active material, in which the battery container is made of a material mainly composed of aluminum and the inner wall surface of the container is insoluble in an electrolytic solution. A lithium secondary battery is disclosed, which is characterized in that the above is formed.

Patent Document 4 describes an assembled battery in which a plurality of laminated cells in which a group of electrode plates are wrapped with a laminated film and sealed in a plate shape and electrode terminals are projected from the center in the thickness direction to the outside are arranged side by side in the thickness direction. It is a holding member that holds one or a plurality of laminated cells, and each laminated cell has the same elastic characteristics from both sides in the thickness direction and is directly or indirectly narrowed by a pair of elastic portions. One elastic portion that urges one laminate cell and another elastic portion that is adjacent to the holding member and that urges the other elastic portion that is adjacent to the one laminate cell. A unit is disclosed as an assembled battery which is arranged so as to be elastically deformed independently of each other.

Japanese Unexamined Patent Publication No. 2012-084247 Japanese Unexamined Patent Publication No. 2012-08424 Japanese Unexamined Patent Publication No. 8-167401 Japanese Unexamined Patent Publication No. 2005-108693

When a container (battery case) made of a highly rigid material such as an aluminum plate or a stainless steel (SUS) plate is used to accommodate the all-solid-state battery laminate, the all-solid-state battery laminate inside the container is subjected to sufficient restraining pressure. Sometimes it was not possible to pressurize. In this case, the internal resistance of the all-solid-state battery laminate may increase, and the battery performance may deteriorate. Further, in this case, since it is difficult to secure the adhesion of the welded portion, there is a possibility that the airtightness of the container cannot be ensured.

Therefore, there is a need to provide an all-solid-state battery that can easily pressurize the all-solid-state battery laminate housed in the battery case and can be well sealed.

As a result of diligent studies, the present inventors have found that the above problems can be solved by the following means, and have completed the present invention. That is, the present invention is as follows:
<Aspect 1> An all-solid-state battery laminate having at least one unit all-solid-state battery, wherein the unit all-solid-state battery includes a positive electrode current collector layer, a positive electrode active material layer, a solid electrolyte layer, a negative electrode active material layer, and a negative electrode active material layer. It includes an all-solid-state battery laminate having a negative electrode current collector layer in this order, and a battery case in which the all-solid-state battery laminate is enclosed.
The battery case includes two laminated film cup-shaped members, a laminated film strip-shaped member, and a resin sealing member.
The two cup-shaped members are arranged so that the bottoms of the two cup-shaped members both face the all-solid-state battery laminate and face each other via the all-solid-state battery laminate.
The strip-shaped member winds around the surface of the all-solid-state battery laminate not covered by the two cup-shaped members, is adhered to the side portions of the two cup-shaped members, and is inside both ends of the strip-shaped member. When viewed in a cross section that is adhered to each other on the side surfaces and is perpendicular to the axial direction of winding of the strip-shaped member, the sealing member is formed on both ends of the strip-shaped member and the cup-shaped member or all of the strip-shaped members. It is arranged in a portion surrounded by the solid-state battery laminate and adhered to the two cup-shaped members and the strip-shaped member.
All solid state battery.

According to the present invention, it is possible to provide an all-solid-state battery in which the all-solid-state battery laminate housed in the battery case can be easily pressurized and can be well sealed.

FIG. 1 shows a schematic view of the all-solid-state battery of the present invention. FIG. 1A shows a top view of the all-solid-state battery of the present invention, FIG. 1B shows a cross-sectional view taken along the line Ib-Ib of FIG. 1A, and FIG. 1C. ) Show a cross-sectional view taken along the line Ic-Ic of FIG. 1 (a).

《All-solid-state battery》
As shown in FIG. 1, the all-solid-state battery 100 of the present invention is
An all-solid-state battery laminate 10 having at least one unit all-solid-state battery, wherein the unit all-solid-state battery is a positive electrode current collector layer, a positive electrode active material layer, a solid electrolyte layer, a negative electrode active material layer, and a negative electrode current collector. Battery cases 20 and 30 containing the all-solid-state battery laminate 10 and the all-solid-state battery laminate 10 having layers in this order.
Equipped with
The battery case includes two laminated film cup-shaped members 20, a laminated film strip-shaped member 30, and a resin sealing member 40.
The two cup-shaped members 20 are arranged so that the bottom portions 22 of the two cup-shaped members 20 face each other with respect to the all-solid-state battery laminate 10 and face each other via the all-solid-state battery laminate 10. ,
The band-shaped member 30 winds around the surface of the all-solid-state battery laminate not covered by the two cup-shaped members 20, is adhered to the side portions 24 of the two cup-shaped members, and is inside both end portions 32 of the band-shaped member 30. When viewed in a cross section that is adhered to each other on the side surfaces and is perpendicular to the axial direction of the winding of the strip-shaped member 30, the sealing member 40 is the both ends 32 of the strip-shaped member 30 and the cup-shaped member 20 or all. It is arranged in a portion surrounded by the solid-state battery laminate 10 and is adhered to two cup-shaped members 20 and a strip-shaped member 30.

The present inventors have found that the all-solid-state battery laminate housed in the battery case can be easily pressurized and can be well sealed by the above configuration. More specifically, since the two cup-shaped members and the band-shaped members constituting the battery case are both made of a laminated film, the battery case is flexible as a whole while ensuring the airtightness inside the battery case. This makes it possible to facilitate the application of the restraining pressure to the all-solid-state battery laminate.

Here, when the strip-shaped member is wound as described above, it is viewed in a cross section perpendicular to the axial direction of winding of the strip-shaped member, that is, a cross section parallel to the line Ib-Ib of FIG. 1 (a). Occasionally, a space may be formed at both ends of the strip-shaped member and at a portion surrounded by the cup-shaped member or the all-solid-state battery laminate, and as a result, the airtightness may not be sufficient.

On the other hand, the present inventors have found that the above problem can be solved by providing a sealing member in a portion corresponding to the above space and adhering the sealing member to the two cup-shaped members and the strip-shaped member. ..

Further, in the above configuration, the terminals connected to the positive electrode current collector layer and the negative electrode current collector layer may be exposed at arbitrary positions, for example, from a cup-shaped member or between the cup-shaped member and the strip-shaped member. it can.

The two cup-shaped members may be arranged on the positive electrode current collector layer and the negative electrode current collector layer, which are located on the outermost side of the all-solid-state battery laminate, respectively, but the side surface of the all-solid-state battery laminate. That is, it is preferable that the batteries are arranged on the plane perpendicular to the positive electrode current collector layer and the negative electrode current collector layer from the viewpoint of facilitating the application of the restraining pressure to the all-solid-state battery laminate.

Hereinafter, the cup-shaped member, the strip-shaped member, and the sealing member constituting the battery case will be described.

<Cup-shaped member>
The cup-shaped member is a member made of two laminate films whose bottoms are all facing the all-solid-state battery laminate and are arranged so as to face each other via the all-solid-state battery laminate. The cup-shaped member may have a recess.

The depth of the recess of the cup-shaped member may be sufficient to secure a side portion having a width sufficient to adhere to the strip-shaped member, for example, 5 mm or more, 10 mm or more, or 15 mm or more. It may be 50 mm or less, 40 mm or less, 30 mm or less, or 20 mm or less.

The thickness of the laminate film constituting the cup-shaped member may be a thickness sufficient to enable sealing of the all-solid-state battery laminate while ensuring flexibility, for example, 500 μm or less, 400 μm or less, 300 μm. Hereinafter, it may be 200 μm or less, or 100 μm or less, and may be 1 μm or more, 3 μm or more, 5 μm or more, 10 μm or more, 30 μm or more, 50 μm or more, or 70 μm or more.

The laminated film constituting the cup-shaped member may be a film having a metal layer and a sealant material layer. As the metal layer used for the laminate film, for example, aluminum or stainless steel (SUS) steel can be used.

As the sealant material layer, for example, polyolefin such as polypropylene, polyethylene, polystyrene, or polyvinyl chloride can be used.

Further, the laminated film may further have an optional base material layer composed of a polyamide such as nylon, a polyester such as polyethylene terephthalate, and a thermoplastic resin such as the above-mentioned polyolefin.

An optional adhesive layer may be present between the above layers. Examples of the adhesive layer include a dry laminate adhesive and a hot melt adhesive.

The laminated films constituting the two cup-shaped members may be of the same type or may be different from each other.

<Strip-shaped member>
The band-shaped member winds around the surface of the all-solid-state battery laminate not covered by the two cup-shaped members and is adhered to the side portions of the two cup-shaped members and bonded to each other on the inner side surfaces of both ends. It is a member made of a laminated film.

Here, the "both ends" mean a portion of the strip-shaped member that does not come into contact with the all-solid-state battery laminate when the strip-shaped member is wound around the all-solid-state battery laminate.

The thickness of the laminated film constituting the strip-shaped member may be a thickness sufficient to ensure flexibility, for example, 500 μm or less, 400 μm or less, 300 μm or less, 200 μm or less, or 100 μm or less, and also. It may be 1 μm or more, 3 μm or more, 5 μm or more, 10 μm or more, 30 μm or more, 50 μm or more, or 70 μm or more.

As the laminating film constituting the strip-shaped member, the laminating film mentioned for the cup-shaped member can be used. The laminated film constituting the strip-shaped member may be the same type as or different from the laminated film constituting the two cup-shaped members.

<Sealing member>
The sealing member is arranged at both ends of the strip-shaped member and a portion surrounded by the strip-shaped member or the all-solid-state battery laminate when viewed in a cross section perpendicular to the axial direction of winding of the strip-shaped member. A resin member that is adhered to a cup-shaped member and a strip-shaped member.

The shape of the sealing member is not particularly limited as long as it can fill the space that may occur at both ends of the strip-shaped member and the portion surrounded by the cup-shaped member or the all-solid-state battery laminate. The shape of the sealing member may be a triangular columnar shape, particularly a triangular columnar column having a height extending over the entire width of the strip-shaped member and having a bottom surface capable of including the above space.

The resin constituting the sealing member may be an arbitrary resin, and a thermoplastic resin is particularly preferable from the viewpoint of ensuring heat weldability with the cup-shaped member and the strip-shaped member. As such a thermoplastic resin, the thermoplastic resin mentioned for the cup-shaped member can be used.

Next, each layer constituting the all-solid-state battery laminate in the all-solid-state battery of the present invention will be described.

In the present invention, the "positive electrode current collector layer" referred to below means a layer in which at least one surface is in contact with the positive electrode active material layer, and only the positive electrode active material layer is used. It may be a current collector layer in contact with the current collector layer, or may be a current collector layer in which the positive electrode active material layer and the negative electrode active material layer can be shared. Similarly, the "negative electrode current collector layer" referred to below may be a current collector layer in which only the negative electrode active material layer is in contact, or a collection that can be shared by the positive electrode active material layer and the negative electrode active material layer. It may be an electric body layer.

<Positive current collector layer>
The conductive material used for the positive electrode current collector layer is not particularly limited, and a known material that can be used for an all-solid-state battery can be appropriately adopted. For example, stainless steel (SUS), aluminum, copper, nickel, iron, titanium, carbon and the like can be mentioned.

The shape of the positive electrode current collector layer according to the present disclosure is not particularly limited, and examples thereof include a foil shape, a plate shape, and a mesh shape. Of these, foil-like is preferable.

<Positive electrode active material layer>
The positive electrode active material layer contains at least the positive electrode active material, and preferably further contains a solid electrolyte described later. In addition, additives used in the positive electrode active material layer of an all-solid-state battery, such as a conductive auxiliary agent or a binder, can be included according to the intended use and purpose of use.

In the present disclosure, the positive electrode active material used is not particularly limited, and known materials are used. For example, sulfur (S), lithium sulfide (Li ₂ S), lithium cobalt oxide (LiCoO ₂ ), lithium nickel oxide (LiNiO ₂ ), lithium manganate (LiMn ₂ O ₄ ), LiCo _1/3 Ni _1/3 Mn. _{Composition represented by 1/3} O ₂ , Li _{1 + x} Mn _{2- xy My} O ₄ (M is one or more metal elements selected from Al, Mg, Co, Fe, Ni, and Zn). Heterogeneous element-substituted Li-Mn spinels and the like can be mentioned, but are not limited thereto.

The conductive auxiliary agent is not particularly limited, and known ones are used. Examples thereof include, but are not limited to, carbon materials such as VGCF (gas phase growth method carbon fiber, Vapor Green Carbon Fiber) and carbon nanofibers, and metal materials.

The binder is not particularly limited, and known binders are used. Examples include, but are not limited to, materials such as polyvinylidene fluoride (PVdF), carboxymethyl cellulose (CMC), butadiene rubber (BR) or styrene butadiene rubber (SBR) or combinations thereof.

<Solid electrolyte layer>
The solid electrolyte layer contains at least a solid electrolyte. The solid electrolyte is not particularly limited, and a material that can be used as the solid electrolyte of the all-solid-state battery can be used. For example, a sulfide solid electrolyte, an oxide solid electrolyte, a polymer electrolyte, and the like can be used.

Examples of solid sulfide electrolytes include, for example, Li ₂ S-SiS ₂ , LiI-Li ₂ S-SiS ₂ , LiI-Li ₂ S-P ₂ S ₅ , LiI-LiBr-Li ₂ S-P ₂ S ₅ , Li ₂ S-P ₂ S _5- LiI-LiBr, Li ₂ S-P ₂ S _5- GeS ₂ , LiI-Li ₂ S-P ₂ O ₅ , LiI-Li ₃ PO _4- P ₂ S ₅ , and Li ₂ SP ₂ S ₅ etc .; Sulfide-based crystalline solid electrolytes such as Li _{10 GeP 2} S ₁₂ , Li ₇ P ₃ S ₁₁ , Li ₃ PS ₄ , and Li _3.25 P _0.75 S ₄ etc. ; And combinations of these can be mentioned.

Examples of the oxide solid _{electrolyte, Li 2 O-B 2 O} 3 -P 2 O 3, Li 2 O-SiO 2, Li 2 O-P 2 O 5 or the like oxide amorphous solid electrolyte, _Li 5 La ₃ Ta ₂ O ₁₂ , Li ₇ La ₃ Zr ₂ O ₁₂ , Li ₆ BaLa ₂ Ta ₂ O ₁₂ , Li ₃ PO _{(4-3 / 2w)} N _w (w <1), Li _3.6 Si _0.6 Examples thereof include, but are not limited to, oxide crystalline solid electrolytes such as P _0.4 O _4.

The sulfide solid electrolyte or oxide solid electrolyte may be glass or crystallized glass (glass ceramic).

Examples of the polymer electrolyte include, but are not limited to, polyethylene oxide (PEO) and polypropylene oxide (PPO).

Further, the solid electrolyte layer may contain a binder or the like, if necessary, in addition to the above-mentioned solid electrolyte. As a specific example, it is the same as the “binder” listed in the above-mentioned “cathode active material layer”, and the description thereof will be omitted here.

<Negative electrode active material layer>
The negative electrode active material layer contains at least the negative electrode active material, and preferably further contains the above-mentioned solid electrolyte. In addition, additives used in the negative electrode active material layer of an all-solid-state battery, such as a conductive auxiliary agent or a binder, can be included according to the intended use and purpose of use.

In the present disclosure, the negative electrode active material used is not particularly limited as long as it can occlude and release metal ions such as lithium ions. Examples thereof include, but are not limited to, metals such as Li, Sn, Si or In, alloys of lithium and titanium, and carbon materials such as hard carbon, soft carbon and graphite.

As for other additives such as the solid electrolyte, the conductive auxiliary agent, and the binder used for the negative electrode active material layer, those described in the above-mentioned "Positive electrode active material layer" and "Solid electrolyte layer" can be appropriately adopted. ..

<Negative electrode current collector layer>
The conductive material used for the negative electrode current collector layer is not particularly limited, and a known material that can be used for an all-solid-state battery can be appropriately adopted. For example, stainless steel (SUS), aluminum, copper, nickel, iron, titanium, carbon and the like can be mentioned.

The shape of the negative electrode current collector layer according to the present disclosure is not particularly limited, and examples thereof include a foil shape, a plate shape, and a mesh shape. Of these, foil-like is preferable.

10 All-solid-state battery laminate 20 Cup-shaped member 22 Bottom of cup-shaped member 24 Side of cup-shaped member 30 Band-shaped member 32 Both ends of band-shaped member 40 Sealing member 100 All-solid-state battery

Claims (1)

An all-solid-state battery laminate having at least one unit all-solid-state battery, wherein the unit all-solid-state battery is a positive electrode current collector layer, a positive electrode active material layer, a solid electrolyte layer, a negative electrode active material layer, and a negative electrode current collector. It includes an all-solid-state battery laminate having layers in this order, and a battery case in which the all-solid-state battery laminate is enclosed.
The battery case includes two laminated film cup-shaped members, a laminated film strip-shaped member, and a resin sealing member.
The two cup-shaped members are arranged so that the bottoms of the two cup-shaped members both face the all-solid-state battery laminate and face each other via the all-solid-state battery laminate.
The strip-shaped member winds around the surface of the all-solid-state battery laminate not covered by the two cup-shaped members, is adhered to the side portions of the two cup-shaped members, and is inside both ends of the strip-shaped member. When viewed in a cross section that is adhered to each other on the side surfaces and is perpendicular to the axial direction of winding of the strip-shaped member, the sealing member is formed on both ends of the strip-shaped member and the cup-shaped member or all of the strip-shaped members. It is arranged in a portion surrounded by the solid-state battery laminate and adhered to the two cup-shaped members and the strip-shaped member.
All solid state battery.

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