JPH05266894A - Solid electrolyte battery and lighium battery - Google Patents

Abstract

PURPOSE:To enlarge the utilization factor of a negative electrode active material and, at the same time, restrain the generation of dendrite by forming a negative electrode active material layer via the deposition of metallic lithium on a solid electrolyte layer, and depositing metallic nickel on an insulation resin film for forming a conductive thin film in contact with the negative electrode active material as a negative electrode current collector body. CONSTITUTION:A lithium battery is constituted of a positive electrode current collector body 1, a positive electrode active material layer 2, a solid electrolyte layer 3, a negative electrode active material layer 4, a negative electrode current collector body 5 and hot melt 6. The body 1 is formed with a nickel foil or the like, and a notched recess section 61 is formed on an edge at one side thereof for functioning as a positive electrode terminal as well. The layer 2 is constituted of vanadium pentoxide with a peripheral edge 1h surrounding the layer 2 left on one plane 1a of the body 1. The layer 3 is constituted of a mixture of methoxy oligoethylene oxypolyphopsphagen and lithium perchlorate. The layer 4 is constituted of metallic lithium deposited on the layer 3, and the body 5 is constituted of a film 51 of polyethylene telephtalate or the like having a metallic nickel deposited conductive thin film 52.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a solid electrolyte battery and a lithium battery.

[0002]

2. Description of the Related Art A typical battery uses a liquid electrolyte (electrolyte) as an electrolyte. However, when an electrolytic solution is used as the electrolyte, there is a problem that the electrolyte decreases due to liquid leakage and depletion. Therefore, a battery (solid electrolyte battery) has been proposed in which a solid electrolyte having ion conductivity is used as an electrolyte to suppress the decrease of the electrolyte. As a typical solid electrolyte battery, a lithium battery using a lithium or lithium alloy for the negative electrode active material layer and a solid electrolyte having lithium ion (Li ⁺ ) conductivity such as polyethylene oxide for the electrolyte is known. .. In a lithium battery, a battery element in which a negative electrode active material layer made of a lithium foil and a xerogel film-shaped positive electrode active material layer are laminated via a solid electrolyte layer, and a pair of opposing side wall portions is a negative electrode current collector. In some cases, it is housed in an outer case composed of a positive electrode current collector and a positive electrode current collector.

[0003]

In a battery using an electrolytic solution as the electrolyte, the electrolyte is in sufficient contact with the active material layer along the uneven surface of the surface of the active material layer, whereas in the solid electrolyte battery, the negative electrode active material is used. There is a problem that a void portion is formed between the material layer and the electrolyte and the contact area between the two becomes small. For example, when a lithium foil is used as the negative electrode active material layer in a lithium battery, even if a flat lithium foil and an electrolyte having irregularities on the surface are brought into close contact with each other, the contact does not increase, and at the interface portion with the electrolyte of the lithium foil, Unreacted lithium remains and the utilization rate of the negative electrode active material is reduced. In addition, when the contact area is small, the current density at the interface between the lithium foil and the electrolyte is high during charging, dendrites are easily generated, and the battery life is shortened.

In addition, when the lithium battery constituting the pair of side wall portions of the outer case is mounted on the place where insulation is required, an insulating sheet must be bonded to either one of the pair of side wall portions. I have to. Therefore, there is a problem that the thickness of the lithium battery is increased by the thickness of the insulating sheet.

An object of the present invention is to provide a solid electrolyte battery capable of increasing the utilization rate of the negative electrode active material and suppressing the generation of dendrite.

Another object of the present invention is to provide a lithium battery which can be placed in a place where insulation is required without increasing the thickness of the battery.

[0007]

According to the invention of claim 1, a solid electrolyte battery in which a negative electrode active material layer and a positive electrode active material layer made of a metal or a metal alloy are laminated with a solid electrolyte layer interposed therebetween, A negative electrode active material layer is constituted by a metal thin film or a metal alloy thin film directly formed on the solid electrolyte layer. The term "metal thin film or metal alloy thin film directly formed on the solid electrolyte layer" as used herein refers to a thin film formed in close contact with the solid electrolyte layer so as to fill the irregularities on the surface of the solid electrolyte layer. is there.

According to a second aspect of the invention, in the solid electrolyte battery according to the first aspect of the invention, the metal thin film or the metal alloy thin film is formed by a vapor deposition film in which a metal is vapor-deposited on the solid electrolyte layer.

According to the third aspect of the present invention, the pair of side wall portions of the outer case in which the negative electrode current collector in contact with the negative electrode active material layer made of lithium or a lithium alloy and the positive electrode current collector in contact with the positive electrode active material layer are opposed to each other. And a negative electrode active material layer and a positive electrode active material layer are targeted for a lithium battery in which a solid electrolyte layer is laminated, and a thin film of lithium or a lithium alloy directly formed on the solid electrolyte layer is used as the negative electrode active material. It constitutes the material layer. A negative electrode current collector is composed of the insulating resin film and a conductive thin film that is directly formed on one surface of the insulating resin film and is in contact with the negative electrode active material layer.

According to a fourth aspect of the invention, in the lithium battery according to the third aspect of the invention, the conductive thin film is entirely formed on one surface of the insulating resin film and is in contact with the negative electrode active material layer of the conductive thin film. A part of the portion not to be exposed is exposed as a negative electrode terminal on the positive electrode current collector side.

According to a fifth aspect of the invention, in the lithium battery of the third aspect of the invention, a terminal forming conductive thin film is formed on the other surface of the insulating resin film, and the terminal forming conductive thin film is formed on the insulating resin film. A negative electrode terminal is formed by connecting to a conductive thin film by a conductive path penetrating through.

[0012]

When the negative electrode active material layer is composed of the metal thin film or the metal alloy thin film directly formed on the solid electrolyte layer as in the invention of claim 1, the surface of the solid electrolyte layer and the surface of the negative electrode active material layer are separated from each other. The close contact increases the contact area between the solid electrolyte layer and the negative electrode active material layer. Therefore, the reaction of the negative electrode active material is promoted at the interface between the negative electrode active material layer and the solid electrolyte layer, and the utilization rate of the negative electrode active material is improved. Further, by increasing the contact area between the solid electrolyte layer and the negative electrode active material layer, the current density at the interface portion between the negative electrode active material layer and the solid electrolyte layer during charging is reduced, and the metal forming the negative electrode active material layer is reduced. Segregation and dendrite formation can be suppressed. Further, according to the present invention, there is an advantage that the amount of metal used in the negative electrode active material layer can be small.

When the metal thin film or the metal alloy thin film is composed of the vapor deposition film as in the second aspect of the invention, the thickness can be easily controlled. As a result, the amount of the negative electrode active material can be set to an appropriate amount according to the amount of the positive electrode active material, and overdischarge of the positive electrode active material can be prevented.

Insulation in which a negative electrode active material layer is composed of a thin film of lithium or a lithium alloy directly formed on a solid electrolyte layer as in the invention of claim 3, and a conductive thin film is directly formed on one surface. When the negative electrode current collector is constituted by the resin film, the contact area between the solid electrolyte layer and the negative electrode active material layer increases, and the contact area between the negative electrode active material layer and the negative electrode current collector also increases, so the contact resistance decreases. The current collection property is also improved, and the charge / discharge characteristics of the battery are improved. Further, according to the present invention, since the current collecting layer is formed of a conductive thin film, even when the insulating resin film is arranged on the outer surface side of the negative electrode current collector forming the side wall portion of the outer case to provide insulation. The thickness of the negative electrode current collector does not increase. Further, since the resin film is easier to process and more flexible than the metal foil, according to the present invention, it is possible to obtain a battery having a high degree of freedom in shape and a high flexibility.

When a terminal structure in which a part of the conductive thin film is exposed as a negative electrode terminal on the positive electrode current collector side as in the invention of claim 4 is used, in the lithium battery of the invention of claim 3, the negative electrode terminal is changed to the positive electrode current collector side. Can be easily provided for.

According to a fifth aspect of the present invention, a conductive thin film for forming a terminal is formed on the other surface of the insulating resin film, and the conductive thin film for forming a terminal is formed by a conductive path penetrating the insulating resin film. When the negative electrode terminal is formed by connecting to, the negative electrode terminal having a desired size can be formed at a desired position outside the insulating resin film.

[0017]

Embodiments of the solid electrolyte battery of the present invention applied to a lithium battery will be described below in detail with reference to the drawings.
FIG. 1A is a plan view of the lithium battery, and FIG.
FIG. 2 is a sectional view taken along line BB of FIG. In both figures,
1 is a positive electrode current collector, 2 is a positive electrode active material layer, 3 is a solid electrolyte layer, 4 is a negative electrode active material layer, 5 is a negative electrode current collector, and 6 is a hot melt.

The positive electrode current collector 1 is formed of a metal foil such as a nickel foil, and a cutout-shaped recess 1 is formed at the edge of one side thereof.
1 is formed. In this embodiment, the positive electrode current collector 1 functions as a positive electrode terminal. The positive electrode active material layer 2 is formed of vanadium pentoxide (V ₂ O ₅ .nH ₂ O) which is a xerogel film arranged on one surface 1 a of the positive electrode current collector 1. The positive electrode active material layer 2 is formed on the surface 1 a of the positive electrode current collector 1 so as to leave the outer peripheral end surface 1 b surrounding the positive electrode active material layer 2. The solid electrolyte layer 3 is formed in close contact with the positive electrode active material layer 2, and specifically, is composed of methoxy oligoethyleneoxy polyphosphazene (MEP7) having ion conductivity and lithium perchlorate (LiClO ₄ ). It is formed by the mixture. The negative electrode active material layer 4 is composed of a metal lithium or lithium alloy vapor deposition film (metal thin film) formed on the solid electrolyte layer 3 by vapor deposition. As the lithium alloy, for example, a lithium-aluminum alloy or the like can be used. The negative electrode current collector 5 is an insulating resin film 51 made of polyethylene terephthalate, polyvinylidene chloride or a laminate of both.
And a conductive thin film 52 formed by vapor-depositing metallic nickel on the entire one surface 51a of the insulating resin film 51, and most of the conductive thin film 52 contacts the negative electrode active material layer 4 There is. A part of the portion 52b of the conductive thin film 52 that does not come into contact with the negative electrode active material layer 4 constitutes the negative electrode terminal 53 that is exposed to the positive electrode current collector 1 side. The negative electrode current collector 5 and the positive electrode current collector 1 are joined together via the hot melt 6 to form a pair of side wall portions of the outer case of the battery. The hot melt 6 is a frame member that melts from the surface side when heated and exhibits adhesiveness, and is specifically made of a polyolefin resin. The hot melt 6 is a ring having a rectangular outline corresponding to the outer peripheral end surface 1b of the current collector 1,
A recess 61 having the same shape as the recess 11 is formed at a position corresponding to the recess 11 of the positive electrode current collector 1. Through the recess 61 and the recess 11 of the positive electrode current collector 1, a part of the conductive thin film 52 of the negative electrode current collector 5 is exposed to the positive electrode current collector 1 side and the negative electrode terminal 53.
Is configured.

Next, a method of manufacturing this lithium battery will be described. First, an amorphous V ₂ O ₅ 2% by weight solution is applied to one surface 1 a of the positive electrode current collector 1 made of nickel foil having a thickness of 20 μm by screen printing or the like, and then dried to dry the positive electrode current collector 1. Thickness of about 10μ on surface 1a
m vanadium pentoxide xerogel film (V ₂ O ₅ · nH ₂
A positive electrode active material layer 2 made of O) was prepared. Next, an annular hot melt 6 was placed on the outer peripheral end surface 1b of the surface 1a of the positive electrode current collector 1, and the hot melt 6 was partially heated to temporarily bond the hot melt 6 onto the outer peripheral end surface 1b. Next, 10% by weight of methoxyoligoethyleneoxypolyphosphazene (MEP7), which is one of the polyphosphazene derivatives, and 6% by weight of LiClO ₄ with respect to the MEP7 were added to 1, 2 and 3.
A solution for a polymer solid electrolyte was prepared by dissolving it in dimethoxyethane (DME), and this solution was applied onto the positive electrode active material layer 2 so as to cover the positive electrode active material layer 2 entirely. Then, this was dried to volatilize DME to form a solid electrolyte layer 3 having a thickness of 100 μm. Next, the positive electrode current collector 1 provided with the solid electrolyte layer 3 and the like is placed in a vapor deposition apparatus, and metallic lithium is vapor-deposited at low temperature on the solid electrolyte layer 3 under high vacuum to form a negative electrode active material layer having a thickness of about 2 μm. 4 was formed. Next, the conductive thin film 5
The negative electrode current collector 5 was placed on the negative electrode active material layer 4 and the hot melt 6 so that 2 was brought into contact with the negative electrode active material layer 4. The negative electrode current collector 5 was formed by vapor-depositing metallic nickel on one surface 51a of an insulating resin film 51 made of polyethylene terephthalate having a thickness of 30 μm to form a conductive thin film 52 having a thickness of 3 μm. Next, the hot melt 6 was connected to the outer peripheral end faces 1b and 52b of the current collectors 1 and 5 by heating. Then, the edge portions on one side of the positive electrode current collector 1 and the hot melt 6 are cut out together to form a recessed portion 11 and a recessed portion 61, and a part of the conductive thin film 52 is exposed on the positive electrode current collector 1 side. Then, the negative electrode terminal 53 was made to complete the lithium battery.

In the present embodiment, the positive electrode current collector 1 and the hot melt 6 are notched at the edges to expose a part of the conductive thin film 52 as the negative electrode terminal 53, but a recess is formed beforehand by pressing or the like. Alternatively, a battery may be manufactured using a positive electrode current collector having a recess and hot melt to expose a part of the conductive thin film 52 as a negative electrode terminal. Further, in this embodiment, the concave portions 11 and 61 are formed to expose a part of the conductive thin film 52 to form the negative electrode terminal 53. However, the negative electrode current collector has a protrusion protruding outside the positive electrode current collector and the hot melt. Alternatively, the conductive thin film formed on the protrusion may be used as a negative electrode terminal.

In the present embodiment, a thin film was directly formed on the solid electrolyte layer of the lithium battery to form the negative electrode active material layer. However, the negative electrode active material layer is made of a metal or alloy other than lithium. Alternatively, a thin film can be directly formed to form the negative electrode active material layer. For example, in a solid electrolyte battery in which the negative electrode active material layer is formed of silver, silver may be vapor-deposited on the solid electrolyte layer to form the silver thin film negative electrode active material layer.

FIG. 2 shows the negative electrode current collector 5 of the embodiment shown in FIG. 1 (B).
FIG. 6 is a partial cross-sectional view of a negative electrode current collector 7 having another structure that can be used instead of. In this negative electrode current collector 7, a conductive thin film 72 that contacts the negative electrode active material layer is formed on one surface 71a of an insulating resin film 71, and terminals are formed at desired positions on the back surface (other surface) 71c. Conductive thin film 73
Are formed and configured. The conductive thin film 72 and the terminal-forming conductive thin film 73 were formed by depositing metallic nickel on the insulating resin film 71. The conductive thin film 72 and the terminal-forming conductive thin film 73 are electrically connected by a conductive path 75 penetrating the through hole 74. In the battery using the negative electrode current collector 7, since the terminal-forming conductive thin film 73 functions as a negative electrode terminal, the recess 1 is formed like the battery shown in FIG.
It is not necessary to form 1,61.

In the above embodiment, the metal thin film, the conductive thin film and the conductive thin film for forming terminals are formed by vapor deposition.
These thin films may be formed by screen printing, plating, sputtering or the like. Also, each thin film may be formed by a different method.

[0024]

According to the invention of claim 1, since the negative electrode active material layer is constituted by the metal thin film or the metal alloy thin film directly formed on the solid electrolyte layer, the utilization factor of the negative electrode active material is improved, It is possible to suppress segregation of the metal forming the negative electrode active material layer and generation of dendrites. Therefore, a battery having high charge / discharge characteristics and a long life can be obtained. Further, there is an advantage that the amount of metal used in the negative electrode active material layer can be small.

According to the second aspect of the invention, since the metal thin film or the metal alloy thin film is composed of a vapor deposition film, the thickness of the thin film can be freely controlled and overdischarge of the positive electrode active material can be prevented. ..

According to the third aspect of the present invention, the negative electrode active material layer is composed of a thin film of lithium or a lithium alloy directly formed on the solid electrolyte layer, and the conductive thin film is directly formed on one surface. Since the negative electrode current collector is composed of the insulating resin film, the charge / discharge characteristics of the battery can be improved, and the battery can be placed in a place where insulation is required without increasing the thickness of the negative electrode current collector. Obtainable.
Further, according to the present invention, it is possible to obtain a battery having high flexibility in shape and high flexibility.

According to the invention of claim 4, since the terminal structure is used in which a part of the conductive thin film is exposed on the positive electrode collector side as a negative electrode terminal, the negative electrode terminal of the battery of the invention of claim 3 is arranged on the positive electrode collector side. Can be easily provided at a desired position.

According to the invention of claim 5, a conductive thin film for forming a terminal is formed on the other surface of the insulating resin film, and the conductive thin film for forming a terminal is connected to the negative electrode by a conductive path penetrating the insulating resin film. Since the conductive thin film is formed by connecting to the material layer, the negative electrode terminal having a desired size can be formed at a desired position outside the insulating resin film.

[Brief description of drawings]

1A is a plan view of an embodiment in which the present invention is applied to a lithium battery, and FIG. 1B is a sectional view taken along line BB of FIG. 1A.

FIG. 2 is a partial cross-sectional view of a negative electrode current collector having another structure which can be used in place of the negative electrode current collector of the embodiment of FIG. 1 (B).

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Positive electrode collector, 2 ... Positive electrode active material layer, 3 ... Solid electrolyte layer, 4 ... Negative electrode active material layer, 5, 7 ... Negative electrode collector, 51, 7
1 ... Insulating resin film, 52, 72 ... Conductive thin film, 53
... Negative electrode terminal, 73 ... Conductive thin film for terminal formation, 75 ... Conductive path.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Kensuke Hironaka, Kensuke Hironaka, 2-1-1, Nishishinjuku, Shinjuku-ku, Tokyo Within Shinjin Todenki Co., Ltd. (72) Inventor, Hayakawa, etc. 2-1-1 Shinshin-Toden Electric Co., Ltd. (72) Inventor Akio Komaki 2-1-1-1 Nishishinjuku, Shinjuku-ku, Tokyo Shinjin-Toden Electric Co., Ltd. (72) Inventor, Weibun Tokushima Prefecture 463 Kagasuno, Kawauchi-cho, Tokushima City Otsuka Chemical Co., Ltd. Tokushima Laboratory (72) Inventor Masatoshi Taniguchi 3-27 Otedori, Chuo-ku, Osaka City, Osaka Otsuka Chemical Co., Ltd.

Claims (5)

[Claims] 1. A solid electrolyte battery in which a negative electrode active material layer made of a metal or a metal alloy and a positive electrode active material layer are stacked via a solid electrolyte layer, wherein the negative electrode active material layer is the solid electrolyte layer. A solid electrolyte battery comprising a metal thin film or a metal alloy thin film formed directly on the solid electrolyte battery. 2. The solid electrolyte battery according to claim 1, wherein the metal thin film or the metal alloy thin film is a vapor deposition film. 3. A pair of side wall portions of the outer case, which face each other, constitute a negative electrode current collector in contact with the negative electrode active material layer made of lithium or a lithium alloy and a positive electrode current collector in contact with the positive electrode active material layer. A lithium battery in which the negative electrode active material layer and the positive electrode active material layer are laminated via a solid electrolyte layer, wherein the negative electrode active material layer is made of lithium or a lithium alloy directly formed on the solid electrolyte layer. A lithium battery comprising a thin film, wherein the negative electrode current collector comprises an insulating resin film and a conductive thin film formed directly on one surface of the insulating resin film and in contact with the negative electrode active material layer. 4. The conductive thin film is entirely formed on the one surface of the insulating resin film, and a part of a portion of the conductive thin film which is not in contact with the negative electrode active material layer is the positive electrode. The lithium battery according to claim 3, wherein the lithium battery is exposed on the side of the current collector as a negative electrode terminal. 5. A conductive thin film for forming a terminal is formed on the other surface of the insulating resin film, and the conductive thin film for forming a terminal is connected to the conductive thin film by a conductive path penetrating the insulating resin film. The lithium battery according to claim 3, wherein a conductive thin film is formed.