JP4184583B2 - Coin type non-aqueous electrolyte battery - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a coin-type (button-type) non-aqueous electrolyte secondary battery in which a material capable of inserting and extracting lithium is used as an active material for a negative electrode and a positive electrode and a lithium ion conductive non-aqueous electrolyte is used.
[0002]
[Prior art]
Conventionally, coin-type (button-type) non-aqueous electrolyte secondary batteries have been increasingly used as backup power sources for equipment due to their high energy density and light weight.
[0003]
Most conventional coin-type (button-type) non-aqueous electrolyte secondary batteries require some form of lithium added to the negative electrode active material. For example, in the case of a battery using a lithium-aluminum alloy for the negative electrode and a 3V-class lithium-containing manganese oxide for the positive electrode, it is necessary to pressure-bond lithium to the aluminum of the negative electrode. In addition, in the case of a battery using carbon for the negative electrode and 3V-class lithium-containing manganese oxide for the positive electrode, it was necessary to electrochemically insert lithium into the negative electrode.
[0004]
In the battery, the material of the gasket that keeps the battery airtight, liquid tight, and the insulation between the positive and negative electrode cans is extremely important. Conventionally, as a gasket material, polypropylene having excellent chemical resistance, elasticity, creep resistance, good moldability, injection moldable and inexpensive has been used. When the battery is mainly used as a memory backup power source, it is often soldered on a printed circuit board together with a memory element after a soldering terminal is welded to the battery. Conventionally, soldering on a printed circuit board has been performed using a soldering iron. However, as equipment becomes smaller and more functional, more electronic components must be mounted within the same area of the printed circuit board. It has become difficult to secure a gap for inserting a soldering iron for soldering. Also, soldering work has been required to be automated for cost reduction. Therefore, solder cream or the like is applied in advance to the part to be soldered on the printed circuit board, and the part is placed on that part, or after placing the part, the solder balls are supplied to the soldered part and soldered. A method is used in which solder is melted and soldered by passing a printed circuit board on which components are mounted in a furnace in a high-temperature atmosphere set so that the part is equal to or higher than the melting point of the solder, for example, 200 to 230 ° C. (Hereinafter referred to as reflow soldering). The coin type (button type) non-aqueous electrolyte secondary battery having a conventional configuration has a drawback in that the function as a battery is impaired when reflow soldering is used because a material considering heat resistance is not used.
[0005]
[Problems to be solved by the invention]
As described above, most of the conventional coin-type (button-type) non-aqueous electrolyte secondary batteries require lithium to be added to the negative electrode active material in some form during the manufacturing process. I had to use metal. In order to add lithium in a metallic state, various processes and facilities were required. For example, when lithium is added by punching, it is necessary to frequently perform maintenance such as wiping because lithium tends to adhere to a punching die or the like. In addition, a facility for storing lithium, which is a dangerous material, was also necessary.
[0006]
In addition, a material obtained by adding lithium to the negative electrode active material in any way in the manufacturing process lacked stability in reflow soldering.
[0007]
For example, in a coin-type (button-type) non-aqueous electrolyte secondary battery having a 3V-class lithium-containing manganese oxide Li4Mn5O12 as a positive electrode and a lithium-aluminum alloy as a negative electrode, most combinations of electrolytes and heat resistance are available when reflow soldering is used. In the battery member, the electrolytic solution reacts with the lithium alloy to cause rapid swelling and rupture.
[0008]
Also in a coin-type (button-type) non-aqueous electrolyte secondary battery in which a 3V-class lithium-containing manganese oxide Li4Mn5O12 is used as a positive electrode and carbon that is contacted or electrochemically doped with lithium is used as a negative electrode, The doped negative electrode reacts, causing sudden swelling and rupture.
[0009]
Furthermore, the conventional coin-type (button-type) non-aqueous electrolyte secondary battery has a problem that boiling and dissolution occur because neither the electrolyte solution, the separator nor the gasket can withstand the reflow temperature.
[0010]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention uses LiCoO 2, LiNiO 2, or LiMnO 2, which is an oxide containing movable lithium, 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.
[0011]
LiCoO 2, LiNiO 2, LiMnO 2, which is an oxide containing movable lithium, or tungsten oxide or a composite oxide of molybdenum and tungsten hardly reacts rapidly with the electrode even at a reflow temperature. Therefore, in order to make a battery that can be reflow soldered, the electrolyte, separator, and gasket, which are constituent elements of the battery, are also heat resistant, and any battery that does not impair the battery performance even in combination with the electrode. We found out as a result of examination. As a result, a coin-type (button-type) non-aqueous electrolyte secondary battery that can withstand the reflow temperature can be provided.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
By using LiCoO 2, LiNiO 2, or LiMnO 2 that is an oxide containing movable lithium, it is not necessary to add lithium to the active material in the manufacturing process. When LiCoO2 is used as the positive electrode, the initial voltage is about 3V, but when the voltage is applied (charging), lithium moves to 4V. When 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 with a battery voltage of about 3 to 2 V can be produced.
[0013]
Our experiments confirmed that when a negative electrode is made of lithium aluminum alloy or lithium-contacted or electrochemically doped carbon or oxide, the electrolyte and negative electrode react rapidly at a reflow temperature exceeding 200 ° C. . On the other hand, it was found that LiCoO 2 and LiNiO 2, which are oxides included in advance by firing or the like in the raw material synthesis stage, do not react rapidly with the electrolyte even at the reflow temperature.
[0014]
Therefore, a positive electrode active material made of LiCoO 2 or LiNiO 2 or LiMnO 2 containing movable lithium and a negative electrode active material made of tungsten oxide or a composite oxide of molybdenum and tungsten were used as electrodes. As a result, it is not necessary to rely on a lithium alloy that is unstable at the reflow temperature for lithium ions that move during charging and discharging, or a carbon or oxide negative electrode that is contacted or electrochemically doped with lithium.
[0015]
LiCoO 2, LiNiO 2, or LiMnO 2 used as the positive electrode active material is an oxide containing movable lithium, and was confirmed to be stable at the reflow temperature.
[0016]
Cobalt and nickel can be combined and may be in the form of LiCoxNiyO2. Further, a part of cobalt or nickel can be replaced with B, P, Si, Mg, or the like.
[0017]
The average particle size of the active material used in the present invention is preferably 500 μm or less, more preferably 100 μm or less, particularly 50 to 0.1 μm when used unexpectedly for reflow soldering. The form of the active material is preferably composed of a primary particle aggregate having an average particle diameter of 1 to 20 microns, which is formed by aggregating primary particles having an average particle diameter of 0.1 to 2.5 microns, particularly preferably. The primary particle aggregate is preferably an aggregate of primary particles having an average particle size of 3.5 to 9.5 microns. Further, in the primary particle aggregate, 80% or more of the total volume is preferably 1 micron or more and 15 microns or less, more preferably 85% or more of the total volume, and further preferably 90% or more of the total volume. is there. The specific surface area is preferably 0.05 to 100 m 2 / g, more preferably 0.1 to 50 m 2 / g, and particularly preferably 0.1 to 30 m 2 / g.
[0018]
When used for reflow soldering, experiments have shown that it is preferable not to include particles having an average particle size of 10 μm or more and a particle size of 10 μm or less of 40% or more. When the average particle size is 10 μm or less or when 40% or more of the particles having a particle size of 10 μm or less is included, the battery may swell due to a rapid reaction with the electrolytic solution.
[0019]
On the other hand, as the oxide used as the negative electrode active material, one having an electrode potential of about 1.5 to 2.5 V was used.
[0020]
The tungsten oxide or the composite oxide of tungsten and molybdenum according to the present invention is stable at a reflow temperature, can reversibly put lithium in and out, and is lower in potential than a positive electrode active material.
[0021]
Tungsten oxide WOx can be used in the range of 2 ≦ x ≦ 3.
[0022]
The complex oxide MoxW (1-x) Oy of molybdenum and tungsten can be used in the range of 0 <x <1, 2 ≦ y ≦ 3.
[0023]
The electrolytic solution is not particularly limited, and an organic solvent used in a conventional non-aqueous secondary battery is used. As the organic solvent, cyclic esters, chain esters, cyclic ethers, chain ethers and the like are used. Specifically, propylene carbonate (PC), ethylene carbonate (EC ), Butylene carbonate (BC), vinylene carbonate, dimethyl carbonate (DMC), diethyl carbonate (DEC), γ-butyrolactone (γBL), 2 methyl-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, methylbutyl carbonate, methylpropyl carbonate, ethylbutyl carbonate, ethylpropyl carbonate, butylpropyl carbonate, propionic acid alkyl ester, malonic acid dialkyl ester, acetic acid alkyl ester, tetrahydrofuran (THF), alkyltetrahydrofuran, dialkylalkyltetrahydrofuran, alkoxy Tetrahydrofuran, dialkoxytetrahydrofuran, 1,3-dioxolane, alkyl-1,3-dioxolane, 1,4-dioxolane, 2-methyltetrahydrofuran, dimethyl sulfoxide, 1,3-dioxolane, formamide, dimethylformamide, dioxolane, acetonitrile , Nitromethane, methyl formate, methyl acetate, methyl propionate, Propionic acid ethyl, organic solvents and their derivatives or a mixture of phosphoric acid triester are preferably used.
[0024]
In addition to the organic solvent, a polymer can be used. As the polymer, those conventionally used in general can be used. For example, polyethylene oxide (PEO), polypropylene oxide, polyethylene glycol diacrylate crosslinked product, polyvinylidene fluoride, polyphosphazene crosslinked product, polypropylene glycol diacrylate A crosslinked body, a crosslinked polyethylene glycol methyl ether acrylate, a crosslinked polypropylene glycol methyl ether acrylate, and the like are preferably used.
[0025]
Examples of main impurities present in the electrolytic solution (nonaqueous solvent) include moisture and organic peroxides (for example, glycols, alcohols, carboxylic acids). Each of the impurities is considered to form an insulating film on the surface of the graphitized material and increase the interfacial resistance of the electrode. Therefore, the cycle life and capacity may be affected. In addition, self-discharge during storage at high temperatures (60 ° C. or higher) may increase. For this reason, it is preferable that the impurities be reduced as much as possible in the electrolyte solution containing the non-aqueous solvent. Specifically, the moisture is preferably 50 ppm or less and the organic peroxide is preferably 1000 ppm or less.
[0026]
In order to perform reflow soldering, it was found that it is stable at the reflow temperature to use a nonaqueous solvent having a boiling point of 200 ° C. or higher at normal pressure as the electrolytic solution. The reflow temperature may rise to about 250 ° C., but even if γ-butyrolactone (γBL) having a boiling point of 204 ° C. at normal pressure is used because the pressure inside the battery is increased at that temperature, There wasn't. In combination with positive and negative electrodes, it was preferable to use a single compound or a composite selected from propylene carbonate (PC), ethylene carbonate (EC), and γ-butyrolactone (γBL).
[0027]
Support salts include lithium perchlorate (LiClO4), lithium hexafluorophosphate (LiPF6), lithium borofluoride (LiBF4), lithium arsenic hexafluoride (LiAsF6), lithium trifluorometasulfonate (LiCF3 SO3), bistri One or more salts of lithium salts (electrolytes) such as lithium fluoromethylsulfonylimide [LiN (CF3 SO2) 2], thiocyanate, and aluminum fluoride can be used. The amount dissolved in the non-aqueous solvent is preferably 0.5 to 3.0 mol / l.
[0028]
In order to perform reflow soldering, lithium hexafluorophosphate (LiPF6), lithium borofluoride (LiBF4), lithium trifluorometasulfonate (LiCF3 SO3) which are fluorine-containing supporting salts from chlorine-based materials such as LiClO4 However, it was stable both thermally and electrically.
[0029]
A solid electrolyte used by mixing a polymer and a supporting salt is produced by a solvent removal method or the like. In this method, the polymer and the supporting salt are dissolved in acetonitrile, 1,2-dimethoxyethane, etc., 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. In a complex having a methacrylic acid ester as a skeleton (POE-PMMA), a mixture of a monomer and a supporting salt can be polymerized by heating or light irradiation.
[0030]
As the separator, an insulating film having a large ion permeability and a predetermined mechanical strength is used. For reflow soldering, glass fibers can be used most stably, but resins such as polyphenylene sulfide, polyethylene terephthalate, polyamide, polyimide having a heat distortion temperature of 230 ° C. or higher can also be used. As the pore diameter of the separator, a range generally used for batteries is used. For example, 0.01 to 10 μm is used. The thickness of the separator is generally used in the battery range, for example, 5 to 300 μm is used.
[0031]
Polypropylene or the like is usually used for gaskets, but when reflow soldering is performed, polyphenylene sulfide, polyethylene terephthalate, and polyamide, which are resins with a heat distortion temperature of 230 ° C. or higher, are not ruptured at the reflow temperature and stored after reflow. However, there was no problem of leakage due to gasket deformation.
[0032]
In addition, polyetherketone resin, polyetheretherketone resin, polyarylate resin, polybutylene terephthalate resin, polycyclohexanedimethylene terephthalate resin, polyethersulfone resin, polyaminobismaleimide resin, polyetherimide resin, tetrafluoroethylene-par Fluoroalkyl vinyl ether copolymer resins, polyether nitrile resins, and liquid crystal polymers can be used. In addition, it has been proved by experiments that the same effect as in this experiment is exhibited even when glass fiber, My Cowisker, ceramic fine powder or the like is added to this material at an addition amount of about 10% by weight or less. .
[0033]
When the battery shape is a coin or a button, the electrode shape is used by compressing a mixture of a positive electrode active material and a negative electrode active material into a pellet shape. In the case of a thin coin or button, an electrode formed in a sheet shape may be punched out. The thickness and diameter of the pellet are determined by the size of the battery.
[0034]
As the pellet pressing method, a generally adopted method can be used, but a die pressing method is particularly preferable. The pressing pressure is not particularly limited, but is preferably 0.2 to 5 t / cm2. The pressing temperature is preferably room temperature to 200 ° C.
[0035]
A conductive agent, a binder, a filler, or the like can be added to the electrode mixture. The kind of the conductive agent is not particularly limited and may be a metal powder, but a carbon-based one is particularly preferable. Carbon materials are the most common, and natural graphite (scale-like graphite, scale-like graphite, earth-like graphite, etc.), artificial graphite, carbon black, channel black, thermal black, furnace black, acetylene black, carbon fiber, etc. are used. As the metal, metal powder such as copper, nickel, silver, or metal fiber is used. Conductive polymers are also used.
[0036]
The amount of carbon added varies depending on the electrical conductivity of the active material, the electrode shape, etc., and is not particularly limited. However, in the case of the negative electrode, it is preferably 1 to 50% by weight, particularly preferably 2 to 40% by weight.
[0037]
When the carbon particle size is in the range of 0.5 to 50 μm, 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. Electron conduction network formation is improved, and active materials that are not involved in electrochemical reactions are reduced.
[0038]
The binder is preferably insoluble in the electrolytic solution, but is not particularly limited. Usually, polyacrylic acid and polyacrylic acid neutralized product, 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, phenol resin, and other polysaccharides, thermoplastic resins, thermosetting resins, rubber elasticity A polymer or the like is used as one kind or a mixture thereof. Although the addition amount of a binder is not specifically limited, 1 to 50 weight% is preferable.
[0039]
Any filler can be used as long as it is a fibrous material that does not cause a chemical change in the constructed battery. In the present invention, fibers such as carbon and glass are used. Although the addition amount of a filler is not specifically limited, 0 to 30 weight% is preferable.
[0040]
As the current collector for the electrode active material, a metal plate having a low electric resistance is preferred. For example, in addition to stainless steel, nickel, aluminum, titanium, tungsten, gold, platinum, baked carbon, etc., the positive electrode has a surface of aluminum or stainless steel treated with carbon, nickel, titanium or silver. Used. As for stainless steel, duplex stainless steel is effective against corrosion. In the case of a coin or button battery, nickel plating is performed on the outside of the battery. Examples of the treatment method include wet plating, dry plating, CVD, PVD, clad formation by pressure bonding, coating, and the like.
[0041]
In addition to stainless steel, nickel, copper, titanium, aluminum, tungsten, gold, platinum, calcined carbon, etc., the negative electrode is made 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 treatment method include wet plating, dry plating, CVD, PVD, clad formation by pressure bonding, coating, and the like.
[0042]
It is also possible to fix the electrode active material and the current collector with a conductive adhesive. As the conductive adhesive, a resin in which carbon or metal powder or fiber is added to a resin dissolved in a solvent, or a conductive polymer dissolved therein is used.
[0043]
In the case of a pellet-shaped electrode, the electrode is fixed by applying between the current collector and the electrode pellet. The conductive adhesive in this case often includes a thermosetting resin.
[0044]
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 and the like is used between the gasket and the positive / negative electrode can. When the sealing agent is transparent, it is colored to clarify the presence or absence of application. Examples of the method for applying the sealant include injection of the sealant into the gasket, application to the positive / negative electrode can, and dipping of the gasket into the sealant solution.
[0045]
The application of the nonaqueous electrolyte secondary battery of the present invention is not particularly limited, and examples thereof include a backup power source for a mobile phone, a pager, etc., a wristwatch power source having a power generation function, and the like.
[0046]
The battery of the present invention is preferably assembled in a dehumidified atmosphere or an inert gas atmosphere. Moreover, it is preferable that the parts to be assembled are also dried in advance. As a method for drying or dehydrating pellets, sheets and other parts, a generally adopted 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 preferably in the range of 100 to 250 ° C. The water content is preferably 2000 ppm or less for the entire battery, and preferably 50 ppm or less for each of the positive electrode mixture, the negative electrode mixture and the electrolyte from the viewpoint of improving charge / discharge cycle performance.
[0047]
Hereinafter, the present invention will be described in more detail with reference to examples.
[0048]
【Example】
In this example, LiCoO2 is used as the positive electrode active material, and WO2 is used as the negative electrode active material. A positive electrode, a negative electrode and an electrolytic solution prepared as described below were used. The size of the battery was 4.8 mm in outer diameter and 1.4 mm in thickness. A cross-sectional view of the battery is shown in FIG.
[0049]
As Example 1, the positive electrode was produced as follows. Commercially available LiCoO2 is crushed into graphite as a conductive agent, and polyacrylic acid as a binder is mixed in a weight ratio of LiCoO2: graphite: polyacrylic acid = 90: 8: 2 to form a positive electrode mixture, This positive electrode mixture was pressure-molded into pellets having a diameter of 2.4 mm at 2 ton / cm 2. Thereafter, the positive electrode pellet 101 obtained in this way was bonded to and integrated with the 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. .
[0050]
The negative electrode was produced as follows. A commercially available WO2 was used as an active material. This active material is mixed with graphite as a conductive agent and polyacrylic acid as a binder at a weight ratio of 70: 25: 5 to form a negative electrode mixture. This mixture is 2 ton / cm @ 2 and has a diameter of 2.4 mm. What was pressure-molded into the pellet was used. After that, the negative electrode pellet 104 obtained in this way was bonded and integrated with the negative electrode case 105 using the electrode current collector 2 made of a conductive resin adhesive containing carbon as a conductive filler, and then the mixture was integrated at 250 ° C. It was dried by heating for hours.
[0051]
The electrolyte solution 107 was sealed in a battery can by 5 μL of LiBF4 dissolved at 1 mol / l in a mixed solvent of γBL and EC in a volume ratio of 1: 1. The positive electrode was produced as follows as Example 2 using the gasket 108 made of PPS. Commercially available LiCoO2 is crushed into graphite as a conductive agent, and polyacrylic acid as a binder is mixed in a weight ratio of LiCoO2: graphite: polyacrylic acid = 90: 8: 2 to form a positive electrode mixture, This positive electrode mixture was pressure-molded into pellets having a diameter of 2.4 mm at 2 ton / cm 2. Thereafter, the positive electrode pellet 101 obtained in this way was bonded to and integrated with the 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. .
[0052]
The negative electrode was produced as follows. A commercially available WO3 was used as an active material. This active material is mixed with graphite as a conductive agent and polyacrylic acid as a binder at a weight ratio of 70: 25: 5 to form a negative electrode mixture. This mixture is 2 ton / cm @ 2 and has a diameter of 2.4 mm. What was pressure-molded into the pellet was used. After that, the negative electrode pellet 104 obtained in this way was bonded and integrated with the negative electrode case 105 using the electrode current collector 2 made of a conductive resin adhesive containing carbon as a conductive filler, and then the mixture was integrated at 250 ° C. It was dried by heating for hours.
[0053]
The electrolyte solution 107 was sealed in a battery can by 5 μL of LiBF4 dissolved at 1 mol / l in a mixed solvent of γBL and EC in a volume ratio of 1: 1. The positive electrode was produced as follows as Example 3 using the gasket 108 made of PPS. Commercially available LiCoO2 is crushed into graphite as a conductive agent, and polyacrylic acid as a binder is mixed in a weight ratio of LiCoO2: graphite: polyacrylic acid = 90: 8: 2 to form a positive electrode mixture, This positive electrode mixture was pressure-molded into pellets having a diameter of 2.4 mm at 2 ton / cm 2. Thereafter, the positive electrode pellet 101 obtained in this way was bonded to and integrated with the 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. .
[0054]
The negative electrode was produced as follows. Commercially available WO2 and MoO2 in a molar ratio of 1: 1 were pulverized in an automatic mortar for 30 minutes, fired in nitrogen at 700 ° C. for 12 hours, and used as an active material. This active material is mixed with graphite as a conductive agent and polyacrylic acid as a binder at a weight ratio of 70: 25: 5 to form a negative electrode mixture. This mixture is 2 ton / cm @ 2 and has a diameter of 2.4 mm. What was pressure-molded into the pellet was used. After that, the negative electrode pellet 104 obtained in this way was bonded and integrated with the negative electrode case 105 using the electrode current collector 2 made of a conductive resin adhesive containing carbon as a conductive filler, and then the mixture was integrated at 250 ° C. It was dried by heating for hours.
[0055]
The electrolyte solution 107 was sealed in a battery can by 5 μL of LiBF4 dissolved at 1 mol / l in a mixed solvent of γBL and EC in a volume ratio of 1: 1. The charging / discharging curve of Example 1 in FIG. 2, Example 2 in FIG. 3, and Example 3 in FIG. FIG. 2 shows charging of a coin-type lithium secondary battery using LiCoO2 as a positive electrode active material and WO2 as a negative electrode active material: 50 μA constant current, 3.3 V for 48 hours, constant discharge, discharge: 10 μA constant current, final voltage 1.8 V It is a figure which shows the charging / discharging characteristic at the time of performing by.
[0056]
FIG. 3 shows charging of a coin-type lithium secondary battery using LiCoO2 as a positive electrode active material and WO3 as a negative electrode active material: 50 μA constant current, 3.3 V for 48 hours, constant discharge, discharge: 10 μA constant current, end voltage 1.8 V It is a charge / discharge characteristic when performed by. FIG. 4 shows charging a coin-type lithium secondary battery using LiCoO2 as a positive electrode active material and Mo0.5W0.5O2 as a negative electrode active material: 50 μA constant current, 3 V 48 hours constant voltage, discharge: 10 μA constant current, final voltage 2 V It is a charge / discharge characteristic when performed by.
[0057]
2 and 3 are charged at a constant current of 50 μA, 3.3 V, 48 hours constant voltage, discharged at a constant current of 10 μA and a final voltage of 1.8 V, and charged in FIG. 4 are maintained at a constant current of 50 μA, 3 V, 48 hours. The discharge was performed at a constant current of 10 μA and a final voltage of 2V.
[0058]
From the results shown in FIGS. 2 to 4, the nonaqueous electrolyte secondary battery in which the positive electrode active material is made of LiCoO 2 or LiNiO 2 and the negative electrode active material is made of tungsten oxide or Mo 0.5 W 0.5 O 2 is good in capacity and cycle characteristics. Results are shown.
[0059]
In performing reflow soldering, one selected from propylene carbonate (PC), ethylene carbonate (EC), γ-butyrolactone (γBL), lithium hexafluorophosphate (LiPF6), lithium borofluoride (LiBF4), Good results have been shown in using an electrolyte selected from lithium trifluorometasulfonate (LiCF3 SO3).
[0060]
【The invention's effect】
As described above in detail, the present invention uses a positive electrode active material made of LiCoO 2 or LiNiO 2, which is an oxide containing movable lithium, and a negative electrode active material made of tungsten oxide or a composite oxide of tungsten and molybdenum. Therefore, it is not necessary to use metallic lithium, which is complicated in handling, in the manufacturing process of assembly.
[0061]
Furthermore, LiCoO 2 or LiNiO 2, which is an oxide containing movable lithium, or a composite oxide of tungsten oxide or molybdenum and tungsten hardly reacts rapidly with the electrode even at the reflow temperature. In addition, a coin type (button type) non-aqueous electrolyte secondary battery that can withstand the reflow temperature can be provided by combining heat resistant gaskets.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a coin-type lithium secondary battery of the present invention. FIG. 2 is a diagram showing discharge characteristics of the battery of Example 1 of the present invention.
FIG. 3 is a graph showing discharge characteristics of the battery of Example 2 of the present invention.
4 is a graph showing discharge characteristics of the battery of Example 3 of the present invention. FIG.
[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 Electrolytic solution 108 Gasket 109 Separator

Claims (2)

In a coin-type non-aqueous electrolyte battery including a positive electrode, a negative electrode, a non-aqueous solvent, an electrolyte containing a supporting salt, a separator, and a gasket member, the positive electrode active material is any one of LiCoO ₂ , LiNiO ₂ , and LiMnO ₂ , The substance is composed of tungsten oxide or a composite oxide of molybdenum and tungsten, and the positive electrode active material and the negative electrode active material have an average particle diameter of 10 μm or more and do not contain 40% or more of particles having a particle diameter of 10 μm or less. The boiling point of the aqueous solvent at normal pressure is 200 ° C. or higher, the supporting salt contains fluorine, the separator is made of glass fiber or a resin having a heat deformation temperature of 230 ° C. or higher, and the gasket has a heat deformation temperature. A coin-type nonaqueous electrolyte secondary battery comprising a resin of 230 ° C. or higher. The nonaqueous solvent having a boiling point of 200 ° C. or higher at normal pressure is a single or composite selected from propylene carbonate (PC), ethylene carbonate (EC), and γ-butyrolactone (γBL), and the supporting salt is A single or composite material selected from lithium hexafluorophosphate (LiPF ₆ ), lithium borofluoride (LiBF ₄ ), and lithium trifluorometasulfonate (LiCF ₃ SO ₃ ), and the thermal deformation temperature is 230 ° C. or higher. The coin type resin according to claim 1, wherein the resin is polyphenylene sulfide, polyethylene terephthalate, polyamide, polyimide, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin, polyether ether ketone, polyether nitrile, or liquid crystal polymer. Non-aqueous electrolyte secondary battery.
more than

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