JP2002063942A - Nonaqueous electrolyte secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a nonaqueous electrolyte secondary coin battery durable to re-flow temperature. SOLUTION: This has a movable lithium containing oxide as a positive electrode active substance, and a negative electrode composed of tungsten oxide or complex oxide of molybdenum and tungsten is used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coin-type (button-type) non-aqueous electrolyte secondary battery using a material capable of inserting and extracting lithium as an active material for a negative electrode and a positive electrode, and using a lithium ion conductive non-aqueous electrolyte. Things.

[0002]

2. Description of the Related Art Conventionally, coin-type (button-type) non-aqueous electrolyte secondary batteries have been increasingly used as backup power supplies for equipment because of their features such as high energy density and light weight.

Most conventional coin-type (button-type) non-aqueous electrolyte secondary batteries require some form of addition of lithium to the negative electrode active material. For example, lithium-
In the case of a battery using an aluminum alloy and a 3V-class lithium-containing manganese oxide for the positive electrode, it was necessary to press-bond lithium to aluminum of the negative electrode. In the case of a battery using carbon as the negative electrode and a lithium-containing manganese oxide of 3V class as the positive electrode, it was necessary to electrochemically insert lithium into the negative electrode.

[0004] In the battery, the material of the gasket for keeping the battery airtight and liquid tight and insulating the positive and negative electrode cans is extremely important. Conventional gasket materials include chemical resistance,
Inexpensive polypropylene, which is excellent in elasticity and creep resistance, has good moldability, and can be injection molded, has been used. When the battery is mainly used as a memory backup power supply, a soldering terminal is welded to the battery, and then the battery is often soldered together with the memory element onto a printed circuit board. Conventionally, soldering on printed circuit boards has been performed using a soldering iron.However, with the miniaturization and higher functionality of equipment, it is necessary to increase the number of electronic components mounted on the same area of the printed circuit board Therefore, it has become difficult to secure a gap for inserting a soldering iron for soldering. Also, the soldering work has been required to be automated for cost reduction. Therefore, apply solder cream etc. to the soldering part on the printed circuit board in advance and place the parts on that part, or supply the small solder balls to the soldered part after placing the parts and solder A method is used in which the solder is melted by passing the printed circuit board on which the parts are mounted in a furnace in a high-temperature atmosphere set so that the temperature of the portion is equal to or higher than the melting point of the solder, for example, 200 to 230 ° C. (Hereinafter referred to as reflow soldering). Conventional coin type (button type)
The non-aqueous electrolyte secondary battery has a drawback that the function as a battery is impaired when reflow soldering is performed because a material considering heat resistance is not used.

[0005]

As described above, most of the conventional coin-type (button-type) non-aqueous electrolyte secondary batteries are
In the manufacturing process, it was necessary to add lithium to the active material of the negative electrode in some form, so that it was necessary to use a lithium metal which was difficult to handle in manufacturing. Various processes and equipment were required to add lithium in a metallic state. For example, when lithium is added by punching, it is necessary to frequently perform maintenance such as wiping because lithium easily adheres to a punching die or the like. In addition, facilities for storing lithium, which is a dangerous substance, were required.

[0006] In addition, the lithium-added active material of the negative electrode in any form during the manufacturing process lacks stability in reflow soldering.

For example, in a coin-type (button-type) nonaqueous electrolyte secondary battery having a lithium-manganese oxide Li4Mn5O12 of 3V class as a positive electrode and a lithium-aluminum alloy as a negative electrode, almost all combinations of electrolytes are provided with reflow soldering. In a liquid or heat-resistant battery member, the electrolytic solution reacts with the lithium alloy, causing rapid swelling or rupture.

[0008] Also, in a coin-type (button-type) nonaqueous electrolyte secondary battery using a lithium-containing manganese oxide Li4Mn5O12 of 3V class as a positive electrode and a negative electrode made of carbon contacted or electrochemically doped with lithium, the electrolyte is Reacts with the lithium-doped negative electrode, causing rapid swelling and bursting.

Further, in the conventional coin-type (button-type) nonaqueous electrolyte secondary battery, neither the electrolyte, the separator, nor the gasket can withstand the reflow temperature.
There was a problem that boiling and melting occurred.

[0010]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a lithium-containing oxide, LiCoO2 or LiNiO2 or LiMnO, which is movable.
2 was used as a positive electrode active material. As the negative electrode, tungsten oxide or a composite oxide of tungsten and molybdenum was used as an electrode.

L is an oxide containing mobile lithium.
iCoO2 or LiNiO2 or LiMnO2,
Tungsten oxide or a composite oxide of molybdenum and tungsten is unlikely to cause a rapid reaction with an electrode even at a reflow temperature. Therefore, in order to make a battery that can be reflow soldered, further, it is necessary to use a battery that has heat resistance even in the electrolytic solution, separator, and gasket that are components of the battery, and that does not impair battery performance even in combination with electrodes. As a result of examination, we found out. As a result, a coin-type (button-type) nonaqueous electrolyte secondary battery that can withstand the reflow temperature can be provided.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS LiCoO2 or LiNiO2 or LiMn, which is a mobile lithium-containing oxide
By using O2, there is no need to add lithium to the active material in the manufacturing process. When LiCoO 2 is used as the positive electrode, the initial voltage is about 3 V, but lithium is moved to 4 V by applying a voltage (charging). If tungsten oxide or a composite oxide of molybdenum and tungsten is used on the negative electrode side so as to occlude the transferred lithium, a battery having a battery voltage of about 3 to 2 V can be manufactured.

According to our experiments, it was found that when lithium aluminum alloy or carbon or oxide doped with lithium or electrochemically doped was used as the negative electrode, the electrolyte and the negative electrode rapidly reacted at a reflow temperature exceeding 200 ° C. It could be confirmed. On the other hand, LiCoO2 or L, which is an oxide previously contained by baking or the like at the stage of synthesizing lithium, is used.
It was found that iNiO2 did not rapidly react with the electrolyte even at the reflow temperature.

Therefore, LiC containing mobile lithium is used.
A positive electrode active material made of oO2, LiNiO2, or LiMnO2 and a negative electrode active material made of tungsten oxide or a composite oxide of molybdenum and tungsten were used as electrodes. This eliminates the need to rely on a lithium alloy which is unstable at the reflow temperature for lithium ions moving at the time of charging and discharging, or a carbon or oxide negative electrode contacted or electrochemically doped with lithium.

LiCoO 2, LiNiO 2, or LiMnO 2 used as a positive electrode active material is an oxide containing movable lithium, and was confirmed to be stable at a reflow temperature.

Further, cobalt and nickel can be compounded and may be in the form of LiCoxNiyO2. Further, a part of cobalt or nickel can be replaced with B, P, Si, Mg and the like.

The average particle size of the active material used in the present invention is 50 when used unexpectedly for reflow soldering.
It is preferably 0 μm or less, more preferably 100 μm or less, and particularly preferably 50 to 0.1 μm. The form of the active material is preferably a primary particle aggregate having an average particle diameter of 1 μm to 20 μm, in which primary particles having an average particle diameter of 0.1 μm or more and 2.5 μm or less are aggregated, and particularly preferably. It is preferable to form a primary particle aggregate having an average particle size of 3.5 μm to 9.5 μm in which primary particles having an average particle size of 0.1 μm to 2.5 μm are aggregated. Further, it is preferable that 80% or more of the total volume of the primary particle aggregate has a particle size of 1 micron or more and 15 microns or less, more preferably 85% or more of the total volume, and still more preferably 90% or more of the total volume. is there. The specific surface area is preferably from 0.05 to 100 m2 / g, more preferably from 0.1 to 50 m2 / g, especially from 0.1 to 30 m2 / g.
g is good.

When used for reflow soldering, an average particle size of 10 μm or more and a particle size of 10 μm or less
Experiments have shown that it is preferable not to contain 0% or more. When the average particle diameter is 10 μm or less, or when 40% or more of particles having a particle diameter of 10 μm or less is included, the battery may suddenly react with the electrolyte to expand.

On the other hand, as the oxide used as the negative electrode active material, an oxide having an electrode potential of around 1.5 to 2.5 V was used.

The tungsten oxide or the composite oxide of tungsten and molybdenum of the present invention is stable at the reflow temperature, can reversibly insert and extract lithium, and is lower in potential than the positive electrode active material.

Tungsten oxide WOx can be used in the range of 2 ≦ x ≦ 3.

A composite oxide of molybdenum and tungsten M
oxW (1-x) Oy can be used in the range of 0 <x <1, 2 ≦ y ≦ 3.

The electrolytic solution is not particularly limited, and an organic solvent used in a conventional non-aqueous secondary battery is used.
In the organic solvent, cyclic esters, chain esters,
Cyclic ethers, chain ethers and the like are used, and specifically, propylene carbonate (PC), ethylene
Carbonate (EC), butylene carbonate (BC), vinylene carbonate, dimethyl carbonate (DM
C), diethyl carbonate (DEC), γ-butyrolactone (γBL), 2methyl-γ-butyrolactone, acetyl-γ-butyrolactone, γ-valerolactone,
1,2-dimethoxyethane (DME), 1,2-ethoxyethane, diethyl ether, ethylene glycol dialkyl ether, diethylene glycol dialkyl ether, triethylene glycol dialkyl ether, tetraethylene glycol dialkyl ether, dipropyl carbonate, methyl ethyl carbonate, methyl Butyl carbonate, methyl propyl carbonate, ethyl butyl carbonate, ethyl propyl carbonate,
Butyl propyl carbonate, alkyl propionate, dialkyl malonate, alkyl acetate, tetrahydrofuran (THF), alkyltetrahydrofuran, dialkylalkyltetrahydrofuran, alkoxytetrahydrofuran, dialkoxytetrahydrofuran, 1,3-dioxolan, alkyl-
1,3-dioxolan, 1,4-dioxolan, 2-methyltetrahydrofuran, dimethylsulfoxide,
Organic solvents such as 1,3-dioxolane, formamide, dimethylformamide, dioxolane, acetonitrile, nitromethane, methyl formate, methyl acetate, methyl propionate, ethyl propionate, phosphoric acid triester, and derivatives and mixtures thereof are preferably used. .

Further, a polymer can be used in addition to the above organic solvent. As the polymer, those conventionally used generally can be used. For example, polyethylene oxide (PEO), polypropylene oxide, crosslinked polyethylene glycol diacrylate, polyvinylidene fluoride, crosslinked polyphosphazene, polypropylene glycol diacrylate A crosslinked product, a crosslinked product of polyethylene glycol methyl ether acrylate, a crosslinked product of polypropylene glycol methyl ether acrylate, and the like are preferably used.

The main impurities present in the electrolytic solution (non-aqueous solvent) include water and organic peroxides (eg, glycols, alcohols, carboxylic acids).
It is considered that each of the impurities forms an insulating film on the surface of the graphitized material and increases the interfacial resistance of the electrode. Therefore, there is a possibility that the cycle life and capacity may be reduced. In addition, self-discharge during high-temperature (60 ° C. or higher) storage may increase. For this reason, it is preferable that the impurities be reduced as much as possible in the electrolytic solution containing the non-aqueous solvent. Specifically, the water content is preferably 50 ppm or less, and the organic peroxide content is preferably 1000 ppm or less.

In order to perform reflow soldering, it was found that the use of a non-aqueous solvent having a boiling point of 200 ° C. or more at normal pressure as an electrolytic solution was stable at the reflow temperature. The reflow temperature may rise to about 250 ° C., but even if γ-butyrolactone (γBL) whose boiling point at normal pressure is 204 ° C. is used, the battery may not burst even if the internal pressure of the battery rises at that temperature. Did not. In combination with the positive and negative electrodes, it was favorable to use a single or a composite selected from propylene carbonate (PC), ethylene carbonate (EC), and γ-butyrolactone (γBL).

As a supporting salt, lithium perchlorate (LiC
lO4), lithium hexafluorophosphate (LiPF6), lithium borofluoride (LiBF4), lithium arsenic hexafluoride (LiAsF6), lithium trifluoromethasulfonate (LiCF3 SO3), lithium bistrifluoromethylsulfonylimide [LiN (CF3 SO2)
2] and one or more lithium salts (electrolytes) such as a thiocyanate salt and an aluminum fluoride salt can be used. The dissolution amount in the non-aqueous solvent is 0.5 to 3.0 mol /
It is desirable to be 1.

To perform reflow soldering, use LiCl
Lithium hexafluorophosphate (LiPF6), lithium borofluoride (LiBF4), and lithium trifluorometasulfonate (LiCF3 SO3), which are more fluorine-containing supporting salts than chlorine-based ones such as O4, are thermally It was stable in characteristics.

The solid electrolyte used by mixing the polymer and the supporting salt is prepared by a solvent removing method or the like. In this method, a polymer and a supporting salt are dissolved in acetonitrile, 1,2-dimethoxyethane, or the like, and then applied to the separator of the present invention and dried. There is also a method in which polypyrrole is dispersed in a solution in which PEO and a supporting salt are dissolved, and the solvent is removed. Complexes having a methacrylic acid ester skeleton (POE-PMM
In A), a mixture of a monomer and a supporting salt can be polymerized by heating or light irradiation.

As the separator, an insulating film having a high ion permeability, a predetermined mechanical strength, and an insulating film is used. For reflow soldering, glass fiber can be used most stably.
Resins such as polyphenylene sulfide, polyethylene terephthalate, polyamide, and polyimide at a temperature of at least ° C can also be used. The pore size of the separator is in a range generally used for batteries. For example, 0.0
1 to 10 μm is used. The thickness of the separator is generally used in the range for batteries, for example, 5 to 300 μm
Is used.

As the gasket, polypropylene is usually used. However, when reflow soldering is performed, polyphenylene sulfide, polyethylene terephthalate, or polyamide having a heat deformation temperature of 230 ° C. or more is free from rupture at the reflow temperature. In the later storage, there was no problem such as liquid leakage due to deformation of the gasket.

In addition, polyetherketone resin, polyetheretherketone resin, polyarylate resin, polybutyleneterephthalate resin, polycyclohexanedimethyleneterephthalate resin, polyethersulfone resin, polyaminobismaleimide resin, polyetherimide resin, tetrafluoroether Ethylene-perfluoroalkyl vinyl ether copolymer resin, polyether nitrile resin and liquid crystal polymer can be used. In addition, 10
Experiments have shown that even if glass fibers, myka whiskers, ceramic fine powder and the like are added in an amount of about not more than about weight%, the same effect as in this experiment can be exhibited.

When the shape of the electrode is a coin or button, the mixture of the positive electrode active material and the negative electrode active material is compressed into a pellet and used. In the case of a thin coin or button, a sheet-shaped electrode may be punched and used. The thickness and diameter of the pellet are determined by the size of the battery.

As a method for pressing the pellets, a method generally used can be used, but a die pressing method is particularly preferable. The pressing pressure is not particularly limited.
5 t / cm2 is preferred. Press temperature is from room temperature to 200 ℃
Is preferred.

A conductive agent, a binder, a filler, and the like can be added to the electrode mixture. The type of the conductive agent is not particularly limited, and may be a metal powder, but a carbon-based material is particularly preferable. Carbon materials are the most common, and natural graphite (scale graphite, flake graphite, earth graphite, etc.), artificial graphite, carbon black, channel black, thermal black, furnace black, acetylene black, carbon fiber, and the like are used. As the metal, metal powder such as copper, nickel, and silver, and metal fibers are used. Conducting polymers are also used.

The amount of carbon added is not particularly limited, although the mixing ratio varies depending on the electric conductivity of the active material, the shape of the electrode, and the like, but is preferably 1 to 50% by weight, particularly preferably 2 to 40% by weight in the case of a negative electrode.

The average particle diameter of carbon is 0.5 to 50 μm.
In the range of, preferably in the range of 0.5 to 15 μm, more preferably in the range of 0.5 to 6 μm, the contact between the active materials becomes good, and the formation of a network of electron conduction is improved,
Active materials that do not participate in the electrochemical reaction are reduced.

The binder is preferably insoluble in the electrolytic solution, but is not particularly limited. Usually, polyacrylic acid and neutralized polyacrylic acid, polyvinyl alcohol,
Carboxymethyl cellulose, starch, hydroxypropyl cellulose, regenerated cellulose, diacetyl cellulose, polyvinyl chloride, polyvinyl pyrrolidone, tetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, ethylene-propylene-diene polymer (EPDM), sulfonated EPDM, styrene butadiene rubber , Polybutadiene, fluoro rubber, polyethylene oxide, polyimide, epoxy resin, polysaccharides such as phenolic resin, thermoplastic resin, thermosetting resin,
A polymer having rubber elasticity is used alone or as a mixture thereof. The amount of the binder added is not particularly limited, but is preferably 1 to 50% by weight.

As the filler, any fibrous material that does not cause a chemical change in the constructed battery can be used. In the case of the present invention, fibers such as carbon and glass are used. The amount of the filler is not particularly limited,
0-30% by weight is preferred.

As the current collector of the electrode active material, a metal plate having a small electric resistance is preferable. For example, for the positive electrode, in addition to materials such as stainless steel, nickel, aluminum, titanium, tungsten, gold, platinum, and calcined carbon, those obtained by treating the surface of aluminum or stainless steel with carbon, nickel, titanium, or silver are used. Used. For stainless steel, duplex stainless steel is effective against corrosion. In the case of coins and button batteries, nickel plating is performed on the outside of the battery. Examples of the processing method include wet plating, dry plating, CVD, PVD, cladding by pressure bonding, coating, and the like.

For the negative electrode, stainless steel, nickel, copper, titanium, aluminum, tungsten, gold,
In addition to platinum, calcined carbon, and the like, those obtained by treating the surface of copper or stainless steel with carbon, nickel, titanium, or silver, an Al—Cd alloy, or the like is used. Examples of the processing method include wet plating, dry plating, CVD, PVD, cladding by pressure bonding, coating, and the like.

It is also possible to fix the electrode active material and the current collector with a conductive adhesive. As the conductive adhesive, a resin obtained by adding carbon or metal powder or fiber to a resin dissolved in a solvent, a conductive polymer dissolved, or the like is used.

In the case of a pellet-shaped electrode, it is applied between the current collector and the electrode pellet to fix the electrode. In this case, the conductive adhesive often contains a thermosetting resin.

In the case of coins and button batteries, a sealant of one or a mixture of asphalt pitch, butyl rubber, fluorinated oil, chlorosulfonated polyethylene, epoxy resin, etc. is used between the gasket and the positive and negative electrode cans.
When the sealant is transparent, it is colored to clarify the presence or absence of application. Examples of the method of applying the sealant include injection of the sealant into a gasket, application to positive and negative electrode cans, dipping of the gasket into a sealant solution, and the like.

The non-aqueous electrolyte secondary battery of the present invention is used for:
Although not particularly limited, for example, there are a backup power supply for a mobile phone and a pager, a power supply for a wristwatch having a power generation function, and the like.

The battery of the present invention is desirably assembled in a dehumidified atmosphere or an inert gas atmosphere. It is also preferable that the parts to be assembled are dried in advance. As a method for drying or dehydrating the pellets, sheets and other parts, a generally employed method can be used. In particular, it is preferable to use hot air, vacuum, infrared rays, far infrared rays, electron beams, and low-humidity air alone or in combination. The temperature is preferably in the range of 80 to 350 ° C, particularly 10 ° C.
A range from 0 to 250 ° C is preferred. The water content of the whole battery is preferably 2000 ppm or less, and it is preferably 50 ppm or less for each of the positive electrode mixture, the negative electrode mixture and the electrolyte from the viewpoint of improving the charge / discharge cycle property.

Hereinafter, the present invention will be described in more detail with reference to examples.

[0048]

EXAMPLE In this example, LiCoO was used as a positive electrode active material.
2. The case where WO2 was used as the negative electrode active material. The positive electrode, the negative electrode, and the electrolyte prepared as described below were used. The battery had an outer diameter of 4.8 mm and a thickness of 1.4 mm. A cross-sectional view of the battery is shown in FIG.

In Example 1, a positive electrode was produced as follows. Commercially obtained pulverized LiCoO2 is made up of graphite as a conductive agent and polyacrylic acid as a binder in a weight ratio of LiCoO2: graphite: polyacrylic acid = 9.
The mixture was mixed at a ratio of 0: 8: 2 to form a positive electrode mixture, and then this positive electrode mixture was pressed into pellets having a diameter of 2.4 mm at 2 ton / cm 2. Thereafter, the positive electrode pellet 101 thus obtained was bonded and integrated with a positive electrode case 103 using an electrode current collector 102 made of a conductive resin adhesive containing carbon, and then heated and dried at 250 ° C. for 12 hours. .

The negative electrode was manufactured as follows. Commercial W
The pulverized O2 was used as the active material. This active material was mixed with graphite as a conductive agent and polyacrylic acid as a binder in a weight ratio of 70: 25: 5, respectively, to form a negative electrode mixture. The mixture was 2 ton / cm 2 and a diameter of 2.4 mm. What was press-molded into pellets was used. Thereafter, the negative electrode pellet 104 thus obtained is bonded and integrated with the negative electrode case 105 using an electrode current collector 2 made of a conductive resin adhesive containing carbon as a conductive filler. Heat drying for hours.

The electrolyte solution 107 was filled with 5 μL of 1 mol / l of LiBF4 dissolved in a mixed solvent of γBL and EC at a volume ratio of 1: 1 and sealed in a battery can. The gasket 108
As Example 2 using a PS product, a positive electrode was prepared as follows. Commercially available pulverized LiCoO2 is mixed with graphite as a conductive agent and polyacrylic acid as a binder in a weight ratio of LiCoO2: graphite: polyacrylic acid = 90: 8: 2 to obtain a positive electrode mixture. This positive electrode mixture was pressed into pellets having a diameter of 2.4 mm at 2 ton / cm 2. Thereafter, the positive electrode pellet 101 thus obtained was bonded and integrated with a positive electrode case 103 using an electrode current collector 102 made of a conductive resin adhesive containing carbon, and then heated and dried at 250 ° C. for 12 hours. .

The negative electrode was manufactured as follows. Commercial W
A material obtained by pulverizing O3 was used as an active material. This active material was mixed with graphite as a conductive agent and polyacrylic acid as a binder in a weight ratio of 70: 25: 5, respectively, to form a negative electrode mixture. The mixture was 2 ton / cm 2 and a diameter of 2.4 mm. What was press-molded into pellets was used. Thereafter, the negative electrode pellet 104 thus obtained is bonded and integrated with the negative electrode case 105 using an electrode current collector 2 made of a conductive resin adhesive containing carbon as a conductive filler. Heat drying for hours.

The electrolyte solution 107 was filled with 5 μL of 1 mol / l of LiBF4 dissolved in a mixed solvent of γBL and EC at a volume ratio of 1: 1 and sealed in a battery can. The gasket 108
As Example 3 using a PS product, a positive electrode was prepared as follows. Commercially available pulverized LiCoO2 is mixed with graphite as a conductive agent and polyacrylic acid as a binder in a weight ratio of LiCoO2: graphite: polyacrylic acid = 90: 8: 2 to obtain a positive electrode mixture. This positive electrode mixture was pressed into pellets having a diameter of 2.4 mm at 2 ton / cm 2. Thereafter, the positive electrode pellet 101 thus obtained was bonded and integrated with a positive electrode case 103 using an electrode current collector 102 made of a conductive resin adhesive containing carbon, and then heated and dried at 250 ° C. for 12 hours. .

The negative electrode was manufactured as follows. Commercial W
O2 and MoO2 in a molar ratio of 1: 1 were ground in an automatic mortar for 30 minutes, baked in nitrogen at 700 ° C. for 12 hours, and used as an active material. This active material was mixed with graphite as a conductive agent and polyacrylic acid as a binder at a weight ratio of 70: 25: 5, respectively, to form a negative electrode mixture. The mixture was 2 ton / cm 2 and a diameter of 2.4 mm.
What was press-molded into pellets was used. Thereafter, the negative electrode pellet 104 thus obtained is bonded and integrated with the negative electrode case 105 using an electrode current collector 2 made of a conductive resin adhesive containing carbon as a conductive filler.
C. for 12 hours.

The electrolyte solution 107 was prepared by dissolving 1 mol / l of LiBF4 in a mixed solvent of γBL and EC at a volume ratio of 1: 1. The gasket 108
FIG. 2 shows the charge / discharge curves of Example 1, FIG. 3 shows the charge / discharge curves of Example 2, and FIG. FIG.
LiCoO2 as a positive electrode active material, WO2 as a negative electrode active material
FIG. 4 is a diagram showing charge / discharge characteristics when a coin-type lithium secondary battery using the following method is charged: 50 μA constant current, 3.3 V, constant voltage holding for 48 hours, discharge: 10 μA constant current, final voltage 1.8 V.

FIG. 3 shows LiCoO 2 as a positive electrode active material,
Charge / discharge characteristics when a coin-type lithium secondary battery using WO3 as the negative electrode active material was charged at a constant current of 50 μA, maintained at a constant voltage of 3.3 V for 48 hours, discharged at a constant current of 10 μA, and a final voltage of 1.8 V. . FIG. 4 shows Li as a positive electrode active material.
Charging a coin-type lithium secondary battery using CoO2 and Mo0.5W0.5O2 as a negative electrode active material: 50 μA constant current, 3V for 48 hours constant voltage holding, discharging: 10 μA constant current,
It is a charge / discharge characteristic when it performed at 2 V of end voltage.

2 and FIG. 3 were charged at a constant current of 50 μA.
3V, constant voltage holding for 48 hours, discharging: 10 μA constant current, end voltage: 1.8 V, charging in FIG.
The constant voltage was maintained and discharged for 48 hours at a constant current of 10 μA and a final voltage of 2 V.

From the results shown in FIGS. 2 to 4, the positive electrode active material was composed of LiCoO2 or LiNiO2, and the negative electrode active material was composed of tungsten oxide or Mo0.5W0.5O2.
The non-aqueous electrolyte secondary battery made of the above showed good results in capacity and cycle characteristics.

In performing reflow soldering, a material selected from propylene carbonate (PC), ethylene carbonate (EC), γ-butyrolactone (γBL), and lithium hexafluorophosphate (LiPF
6), lithium borofluoride (LiBF4) and lithium trifluorometasulfonate (LiCF3 SO3) showed good results when used as an electrolyte.

[0060]

As described above in detail, the present invention relates to an oxide containing lithium capable of transferring, such as LiCoO2 or LiCoO2.
By using a positive electrode active material composed of NiO2 and a negative electrode active material composed of tungsten oxide or a composite oxide of tungsten and molybdenum, metal lithium, which was complicated in handling, does not have to be used in the manufacturing process of assembly.

Further, LiCoO2 or LiNiO2, which is a mobile oxide containing lithium, or a composite oxide of tungsten oxide or molybdenum and tungsten, does not easily react with the electrode even at the reflow temperature. By combining a liquid, a separator, and a gasket having heat resistance, a coin-type (button-type) nonaqueous electrolyte secondary battery capable of withstanding a reflow temperature could be provided.

[Brief description of the drawings]

FIG. 1 is a sectional view of a coin-type lithium secondary battery of the present invention.

FIG. 2 is a view showing the discharge characteristics of the battery of Example 1 of the present invention.

FIG. 3 is a view showing discharge characteristics of a battery according to Example 2 of the present invention.

FIG. 4 is a diagram showing discharge characteristics of a battery according to Example 3 of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 101 Positive electrode pellet 102 Electrode current collector 103 Positive electrode case 104 Negative electrode pellet 105 Negative electrode case 107 Electrolyte 108 Gasket 109 Separator

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) H01M 4/48 H01M 4/48 4/58 4/58 (72) Inventor Shunji Watanabe Aoba-ku, Sendai City, Miyagi Prefecture 45-1 Kami-Aiko Matsubara in SII Microparts Co., Ltd. (72) Inventor Sakai Tsuguo 45-1 Kami-Aiko Matsubara in Aoba-ku, Sendai City, Miyagi Prefecture F-term in References 5H011 AA02 AA09 FF03 GG02 HH02 KK04 5H021 AA06 CC01 EE02 EE28 HH06 5H029 AJ12 AJ14 AK03 AL02 AL03 AM02 AM03 AM04 AM05 AM07 BJ03 DJ03 DJ04 DJ15 EJ06 EJ12 EJ14 HJ02 HJ05 HJ14 DAH19A19CB

Claims (8)

[Claims] 1. A non-aqueous electrolyte battery comprising a positive electrode, a negative electrode, a non-aqueous solvent, an electrolyte containing a supporting salt, a separator and a gasket, wherein the positive electrode active material comprises an oxide to which Li can move, and the negative electrode active material comprises Is made of tungsten oxide or a composite oxide of molybdenum and tungsten. 2. The active material used for the positive electrode or the negative electrode has an average particle size of 10 μm or more and does not contain 40% or more of particles having a particle size of 10 μm or less, and the non-aqueous solvent has a boiling point of 200 at normal pressure. C. or more, and the supporting salt contains fluorine, and the separator is made of glass fiber or a resin having a heat deformation temperature of 230 ° C. or more, and the gasket is made of a resin having a heat deformation temperature of 230 ° C. or more. The non-aqueous electrolyte secondary battery according to claim 1. 3. The non-aqueous solvent having a boiling point of 200 ° C. or more at normal pressure is a single or composite selected from propylene carbonate (PC), ethylene carbonate (EC), and γ-butyrolactone (γBL); The supporting salt is a single or a compound selected from lithium hexafluorophosphate (LiPF6), lithium borofluoride (LiBF4), and lithium trifluorometasulfonate (LiCF3 SO3), and the heat distortion temperature is 230C. The resin according to claim 1, wherein the resin is polyphenylene sulfide, polyethylene terephthalate, polyamide, polyimide, tetrafluoroethylene-perfluoroalkylvinyl ether copolymer resin, polyether ether ketone, polyether nitrile, or liquid crystal polymer. Water electrolyte secondary battery. 4. The tungsten oxide has a general formula WOx
The non-aqueous electrolyte secondary battery according to claim 1, wherein 2 ≦ x ≦ 3. 5. The composite oxide of molybdenum and tungsten has the general formula: MoxW (1-x) Oy, where 0 <
2. The non-aqueous electrolyte secondary battery according to claim 1, wherein x <1, 2 ≦ y ≦ 3. 3. 6. The oxide capable of releasing Li is represented by the following formula (1): Lix My Lz O2 (1) (where M is a transition metal element, L is periodic table IIIB, IVB
And one or more elements selected from the group consisting of non-metal elements and semi-metal elements of group VB and VB, alkaline earth metal elements, and metal elements such as Zn, Cu, and Ti. 0 <x ≦ 1.15, 0.85 ≦ y + z ≦ 1.
3. The non-aqueous electrolyte secondary battery according to claim 1, wherein the non-aqueous electrolyte secondary battery is represented by a composite oxide having a layered structure represented by 3, 0 <z). 7. The non-volatile memory device according to claim 1, wherein the M element constituting the composite oxide having a layered structure represented by the formula (1) is at least one selected from Co, Ni and Mn. Water electrolyte secondary battery. 8. An element L constituting the composite oxide having a layered structure represented by the formula (1) is at least one element selected from the group consisting of boron B, silicon Si, and phosphorus P. 2. The non-aqueous electrolyte secondary battery according to claim 1, comprising a metal element or a metalloid element.