JP3663763B2 - Non-aqueous electrolyte secondary battery and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a high-capacity non-aqueous electrolyte secondary battery excellent in charge / discharge cycle characteristics, and a non-aqueous electrolyte having a large discharge capacity in which a negative electrode material is mainly an amorphous chalcogen compound and / or an amorphous oxide. The present invention relates to improvement of charge / discharge characteristics such as charge / discharge cycle life of a secondary battery.
[0002]
[Prior art]
Typical negative electrode materials for non-aqueous electrolyte secondary batteries are lithium metal and lithium alloy, but when they are used, so-called dendrites in which lithium metal grows in a dendritic shape during charge / discharge are generated, causing internal short circuit. Or because of the high activity of the dendrite itself, there was a risk of fire.
[0003]
In contrast, calcined carbonaceous materials capable of reversibly inserting and releasing lithium have come into practical use. The disadvantage of this carbonaceous material is that it has electrical conductivity, so that lithium metal may be deposited on the carbonaceous material during overcharge or rapid charge, resulting in the deposition of dendrites. .
[0004]
In order to avoid this, the charger is devised or a method of preventing overcharging by reducing the positive electrode active material is adopted, but the latter method limits the amount per active material. Therefore, the discharge capacity is also limited. Further, since the carbonaceous material has a relatively low density, the discharge capacity is limited in a double sense that the capacity per volume is low.
[0005]
It is possible to use a lithium foil on a carbon material by press-bonding or laminating it, as disclosed in JP-A-61-54165, JP-A-2-82447, JP-A-2-21562, JP-A-3-122974, JP-A-3-272571, -144471, 5-144472, 5-144473, and 5-151995, the carbon material is used as the negative electrode active material, and the above problems are essentially eliminated. It was not a solution.
[0006]
On the other hand, as negative electrode materials other than lithium metal, lithium alloy, and carbonaceous material, TiS which can occlude and release lithium ions ₂ LiTiS ₂ (US Pat. No. 983476), WO ₂ , FeO _Three Lithium compounds (Japanese Patent Laid-Open No. 3-11270), Nb ₂ O _Five (Japanese Patent Publication No. 62-59412, Japanese Patent Laid-Open No. 2-82447), iron oxide (FeO, Fe ₂ O _Three , Fe _Three O _Four ), Cobalt oxide (CoO, Co ₂ O _Three , Co _Three O _Four ) (Japanese Patent Laid-Open No. 3-291862) is known. None of these compounds has a low oxidation-reduction potential, and a non-aqueous electrolyte secondary battery having a high discharge potential of 3 V cannot be realized. Also, the discharge capacity is not satisfactory.
[0007]
In order to improve the above-mentioned drawbacks, as a non-aqueous electrolyte secondary battery having a high discharge potential with an average discharge voltage of 3 to 3.6 V, oxidation of Sn, V, Si, B, Zr, etc. to the negative electrode material And composite oxides thereof have been proposed (JP-A-5-174818, JP-A-6-60867, JP-A-6-275267, JP-A-6-325765, JP-A-6-338324, EP -615296). These oxides such as Sn, V, Si, B, and Zr, and composite oxides thereof, are combined with a positive electrode of a transition metal compound containing a certain kind of lithium, so that the average discharge voltage is 3 to 3.6 V class. However, there is a problem in that the charge / discharge cycle characteristics are not sufficient, although a non-aqueous electrolyte secondary battery having a large discharge capacity and almost no dendrite generation in a practical range and extremely high safety is provided.
[0008]
In order to improve cycleability, it has been proposed that phenanthrolinesulfonic acid Na or the like be present in the battery (Japanese Patent Laid-Open No. 7-065863). This method is difficult, and it is necessary to re-apply only the additive to the prepared electrode, and it is difficult to distribute it uniformly in the battery. .
[0009]
[Problems to be solved by the invention]
An object of the present invention is to improve the charge / discharge cycle characteristics of a nonaqueous electrolyte secondary battery having a large discharge capacity.
[0010]
[Means for Solving the Problems]
According to one aspect of the present invention, a positive electrode including a material capable of reversibly occluding and releasing lithium, including three or more atoms selected from Group 1, 2, 13, 14, and 15 atoms of the periodic table, A nonaqueous electrolyte secondary battery having a negative electrode composed of an amorphous chalcogen compound and / or an amorphous oxide, a nonaqueous electrolyte containing a lithium salt, and a separator has a dew point of −80 ° C. to −30 ° C. An air blowing process is performed using a certain air.
[0011]
According to another aspect of the present invention, the cathode includes a material capable of reversibly occluding and releasing lithium, and includes three or more kinds of atoms selected from periodic table 1, 2, 13, 14, and 15 atoms. A method for producing a non-aqueous electrolyte secondary battery having a negative electrode mainly composed of an amorphous chalcogen compound and / or an amorphous oxide, a non-aqueous electrolyte containing a lithium salt, and a separator is provided in the battery. Before the injection, the nonaqueous electrolyte is subjected to an air blowing process using air having a dew point of −80 ° C. to −30 ° C.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Although the preferable aspect of this invention is hung up below, this invention is not limited to this.
[0013]
(1). A positive electrode containing a material capable of reversibly occluding and releasing lithium, and containing three or more kinds of atoms selected from periodic table 1, 2, 13, 14, 15 atoms, mainly amorphous chalcogen compounds and / or non A nonaqueous electrolyte secondary battery having a negative electrode made of a crystalline oxide, a nonaqueous electrolyte containing a lithium salt, and a separator, wherein the nonaqueous electrolyte is subjected to air blowing treatment, battery.
[0014]
(2). The nonaqueous electrolyte secondary battery according to Item 1, wherein at least one of the negative electrode materials is represented by the general formula (1).
[0015]
M ₁ M _2p M _4q M _6r General formula (1)
(Where M ₁ , M ₂ Is different from at least one selected from Si, Ge, Sn, Pb, P, B, Al, Sb, M _Four Is at least one selected from Li, K, Na, Cs, Mg, Ca, Sr, Ba, M ₆ Is at least one selected from O, S and Te, p and q are each 0.001 to 10, and r is a number from 1.00 to 50. )
[0016]
(3). A positive electrode containing a material capable of reversibly occluding and releasing lithium, and containing three or more kinds of atoms selected from periodic table 1, 2, 13, 14, 15 atoms, mainly amorphous chalcogen compounds and / or non A method for producing a non-aqueous electrolyte secondary battery having a negative electrode made of a crystalline oxide, a non-aqueous electrolyte containing a lithium salt, and a separator, wherein air is introduced into the non-aqueous electrolyte before the non-aqueous electrolyte is injected into the battery. A method for producing a non-aqueous electrolyte secondary battery, characterized by performing a blowing process.
[0017]
(4). Item 4. The method for producing a nonaqueous electrolyte secondary battery according to Item 3, wherein the air blowing treatment is performed by placing air and a nonaqueous electrolyte in a container and shaking the nonaqueous electrolyte in sufficient contact with air.
[0018]
(5). The non-aqueous electrolyte secondary according to Item 3, wherein the air blowing treatment is performed by blowing air at a wind speed of 0.1 to 10 meters on the liquid surface of the non-aqueous electrolyte for 0.1 to 6 hours. Battery manufacturing method.
[0019]
(6). Item 4. The method for producing a nonaqueous electrolyte secondary battery according to Item 3, wherein the air blowing treatment is performed by blowing air into the nonaqueous electrolyte with a nozzle.
[0020]
(7). Item 7. The method for producing a non-aqueous secondary battery according to any one of Items 3 to 6, wherein the air has a dew point of −80 ° C. to −30 ° C.
[0021]
(8). Item 8. The method for producing a nonaqueous secondary battery according to any one of Items 3 to 7, wherein the air blowing treatment is performed at a temperature of -10 ° C to 20 ° C.
[0022]
(9). Item 9. The method for producing a nonaqueous secondary battery according to any one of Items 3 to 8, wherein the air blowing treatment is performed within 1 hour before the nonaqueous electrolyte is injected into the battery.
[0023]
(Ten). The nonaqueous electrolyte secondary battery according to item 2, wherein at least one of the negative electrode materials is represented by the general formula (2).
[0024]
SnM _3p M _5q M _7r General formula (2)
(Where M _Three Is at least one selected from Si, Ge, Pb, P, B, Al, M _Five Is at least one selected from Li, K, Na, Cs, Mg, Ca, Sr, Ba, M ₇ Is at least one selected from O and S, p and q are each 0.001 to 10, and r is a number from 1.00 to 50. )
[0025]
(11). At least one of the positive electrode materials is Li _x CoO ₂ , Li _x NiO ₂ , Li _x MnO ₂ , Li _x Co _a Ni ( ₁ -A) O ₂ , Li _x Co _b V ( ₁ -B) O _z , Li _x Co _b Fe ( ₁ -B) O ₂ , Li _x Mn ₂ O _Four , Li _x Mn _c Co ( ₂ -C) O _Four , Li _x Mn _c Ni ( ₂ -C) O _Four , Li _x Mn _c V ( ₂ -C) O _Four , Li _x Mn _c Fe ( ₂ -C) O _Four (From the formula, x = 0.2 to 1.2, a = 0.1 to 0.9, b = 0.8 to 0.98, c = 1.6 to 1.96, z = 2.01 2.3) The nonaqueous electrolyte secondary battery according to any one of Items 1, 2, and 10 above.
[0026]
In the present invention, charge / discharge cycle characteristics can be improved without impairing the high capacity of the non-aqueous electrolyte secondary battery because the non-aqueous electrolyte is subjected to air blowing treatment.
[0027]
The air blowing process in the present invention is a process of adding air to a nonaqueous electrolyte prepared, transported or stored in an inert gas atmosphere such as argon gas or nitrogen gas.
[0028]
The air blowing process is performed by placing air and a non-aqueous electrolyte in a container and shaking so that the entire non-aqueous electrolyte is in sufficient contact with the air. The container preferably has a volume of 0.2 to 10 liters, and preferably 0.1 to 0.5 times the volume of nonaqueous electrolyte and the remaining volume is filled with air.
[0029]
The container is preferably shaken with an amplitude of 0.5 to 20 centimeters and a frequency of 0.5 to 10 hertz. Further, instead of shaking the container, the nonaqueous electrolyte may be shaken directly using a stirring blade or the like. The stirring blade is preferably 1 to 15 centimeters in length, preferably 20 to 1000 rpm in rotation, and shifted to the non-aqueous electrolyte by shifting from the center of the container or installing a baffle plate inside the container. It is preferable to sufficiently entrain air.
[0030]
In the shaking treatment, after the treatment for a certain time, the treatment may be stopped and the non-aqueous electrolyte inside the container may be taken out and used. And the air may be injected, and the treated nonaqueous electrolyte and air may be gradually extracted from the other side of the container and used for injection into the battery.
[0031]
The processing time when processing for a certain period of time is preferably 10 seconds to 600 seconds, more preferably 20 seconds to 300 seconds, and most preferably 30 seconds to 180 seconds. When the non-aqueous electrolyte is gradually injected / withdrawn while being treated, the non-aqueous electrolyte mass injected / withdrawn per minute is preferably 2 to 30 times, more preferably 3 to 20 times, and most preferably 5 times. To 15 times the non-aqueous electrolyte should be always present inside the container.
[0032]
Further, the air blowing treatment of the present invention can be carried out by blowing an air wind with a wind speed of 0.1 to 10 meters over the liquid surface of the nonaqueous electrolyte for 0.1 to 6 hours. A container with an open lid may be filled with a non-aqueous electrolyte and left for treatment for a predetermined period of time under an air blast. Alternatively, an air blast may be introduced into the container filled with the non-aqueous electrolyte to You may discharge | emit from this container after passing on a surface. Alternatively, the air wind may be blown onto the non-aqueous electrolyte flow path maintained horizontally.
[0033]
Moreover, the air blowing process of the present invention can be carried out by blowing air into a non-aqueous electrolyte in the form of a bubble using a nozzle. The nozzle preferably facilitates bubble generation by reducing the pores. More preferably, a large number of fine holes are arranged at the tip of the nozzle to make the generated bubbles fine (for example, an air nozzle used for an aquarium for appreciation fish; a trade name “Stone”, and also used for cleaning a gas in a laboratory, for example) A ball filter incorporated in the gas cleaning bottle; a large number of holes of 1 to 100 μm are opened). Most preferably, a plurality of nozzles having a large number of fine holes are arranged in the non-aqueous electrolyte.
[0034]
The dew point of the air used for the air blowing treatment of the present invention is preferably -80 ° C to -30 ° C, more preferably -80 ° C to -40 ° C, and most preferably -80 ° C to -50 ° C.
[0035]
The temperature at which the air blowing treatment of the present invention is carried out is preferably -10 ° C to 20 ° C, more preferably -5 ° C to 15 ° C, and most preferably 0 ° C to 10 ° C. The treatment may be performed preferably at a predetermined temperature of air, more preferably at a predetermined temperature of the nonaqueous electrolyte, and most preferably at a predetermined temperature of air and the nonaqueous electrolyte. It is good to carry out.
[0036]
The air blowing treatment is preferably completed within 2 hours, more preferably within 1 hour, and most preferably within 0.5 hour, before starting to inject the non-aqueous electrolyte into the battery.
[0037]
The electrolyte is generally composed of a solvent and a supporting salt dissolved in the solvent, and the supporting salt is preferably a lithium salt (anion and lithium cation).
[0038]
Examples of the electrolyte solvent that can be used in the present invention include propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, γ-butyrolactone, methyl formate, methyl acetate, 1,2-dimethoxyethane, tetrahydrofuran, 2 -Methyltetrahydrofuran, dimethyl sulfoxide, 1,3-dioxolane, formamide, dimethylformamide, dioxolane, dioxane, acetonitrile, nitromethane, ethyl monoglyme, phosphate triester, trimethoxymethane, dioxolane derivative, sulfolane, 3-methyl-2- Non-polymers such as oxazolidinone, propylene carbonate derivatives, tetrahydrofuran derivatives, ethyl ether, 1,3-propane sultone, etc. Can be exemplified ton organic solvent, mixed and used alone or in combination. Among them, carbonate-based solvents are preferable, and those containing cyclic carbonate and / or acyclic carbonate are preferable. As the cyclic carbonate, ethylene carbonate and propylene carbonate are preferable. Moreover, as an acyclic carbonate, it is preferable to include diethyl carbonate, dimethyl carbonate, and methyl ethyl carbonate.
[0039]
Examples of the supporting salt dissolved in these solvents that can be used in the present invention include LiClO. _Four , LiBF _Four , LiPF ₆ , LiCF _Three SO _Three , LiCF _Three CO ₂ , LiAsF ₆ , LiSbF ₆ , Lower aliphatic lithium carboxylate, LiAlCl _Four Li salts such as LiCl, LiBr, LiI, chloroborane lithium and lithium tetraphenylborate can be raised, and these can be used alone or in combination. Above all, LiBF _Four And / or LiPF ₆ What melt | dissolved is preferable.
[0040]
The concentration of the supporting salt is not particularly limited, but is preferably 0.2 mol to 3 mol per liter of the electrolyte solution.
[0041]
As a combination of electrolytes that can be used in the present invention, LiCF is added to an electrolytic solution in which ethylene carbonate, propylene carbonate, 1,2-dimethoxyethane, dimethyl carbonate, or diethyl carbonate is appropriately mixed. _Three SO _Three LiClO _Four , LiBF _Four And / or LiPF ₆ An electrolyte containing is preferred. In particular, LiCF is used as a mixed solvent of propylene carbonate or ethylene carbonate and 1,2-dimethoxyethane and / or diethyl carbonate. _Three SO _Three LiClO _Four , LiBF _Four And / or LiPF ₆ In particular, at least ethylene carbonate and LiPF. ₆ The thing containing is preferable.
[0042]
The amount of these electrolytes added to the battery is not particularly limited, but a necessary amount can be used depending on the amount of the positive electrode active material and the negative electrode material and the size of the battery.
[0043]
Hereinafter, other materials and manufacturing methods for making the nonaqueous electrolyte secondary battery of the present invention will be described in detail. The positive and negative electrodes used in the nonaqueous electrolyte secondary battery of the present invention can be prepared by coating a positive electrode mixture or a negative electrode mixture on a current collector. In addition to the positive electrode active material or the negative electrode material, the positive electrode or the negative electrode mixture can contain a conductive agent, a binder, a dispersant, a filler, an ionic conductive agent, a pressure enhancer, and various additives, respectively.
[0044]
The negative electrode material used in the present invention is preferably mainly amorphous at the time of battery incorporation. The term “amorphous” as used herein refers to an X-ray diffraction method using CuKα rays, which has a broad scattering band having a peak at 20 ° to 40 ° with a 2θ value, and has a crystalline diffraction line. Also good.
[0045]
Preferably, the strongest intensity of the crystalline diffraction lines seen at 2θ values of 40 ° or more and 70 ° or less is 500 of diffraction line intensities at the apexes of broad scattering bands seen at 2θ values of 20 ° or more and 40 ° or less. It is preferably not more than twice, more preferably not more than 100 times, particularly preferably not more than 5 times, and most preferably not having a crystalline diffraction line.
[0046]
The negative electrode material used in the present invention is preferably represented by the following general formula (1).
[0047]
M ₁ M _2p M _4q M _6r General formula (1)
Where M ₁ , M ₂ Is at least one selected from Si, Ge, Sn, Pb, P, B, Al, Sb, preferably Si, Ge, Sn, P, B, Al, particularly preferably Si, Sn, P. , B and Al. M _Four Is at least one selected from Li, Na, K, Rb, Cs, Mg, Ca, Sr, and Ba, preferably K, Cs, Mg, and Ca, and particularly preferably Cs and Mg. M ₆ Is at least one selected from O, S and Te, preferably O and S, particularly preferably O. p and q are each 0.001 to 10, preferably 0.01 to 5, and particularly preferably 0.01 to 2. r is 1.00-50, preferably 1.00-26, particularly preferably 1.02-6. M ₁ , M ₂ The valence of is not particularly limited, and may be a single valence or a mixture of valences. M ₁ , M ₂ , M _Four The ratio of M is ₂ And M _Four Is M ₁ In the range of 0.001 to 10 molar equivalents relative to ₆ (The value of r in general formula (1)) also changes continuously.
[0048]
Among the compounds listed above, in the present invention, M ₁ Is preferably Sn, represented by the general formula (2).
[0049]
SnM _3p M _5q M _7r General formula (2)
Where M _Three Is at least one selected from Si, Ge, Pb, P, B, and Al, preferably Si, Ge, P, B, and Al, particularly preferably Si, P, B, and Al. M _Five Is at least one selected from Li, Na, K, Rb, Cs, Mg, Ca, Sr and Ba, preferably Cs and Mg, particularly preferably Mg. M ₇ Is at least one selected from O and S, preferably O. p and q are each 0.001 to 10, preferably 0.01 to 5, more preferably 0.01 to 1.5, and particularly preferably 0.7 to 1.5. r is 1.00-50, Preferably it is 1.00-26, Most preferably, it is 1.02-6.
[0050]
Although the example of the negative electrode material of this invention is shown below, this invention is not limited to these.
SnAl _0.4 B _0.5 P _0.5 K _0.1 O _3.65 ,
SnAl _0.4 B _0.5 P _0.5 Na _0.2 O _3.7 ,
SnAl _0.4 B _0.3 P _0.5 Rb _0.2 O _3.4 ,
SnAl _0.4 B _0.5 P _0.5 Cs _0.1 O _3.65 ,
SnAl _0.4 B _0.5 P _0.5 K _0.1 Ge _0.05 O _3.85 ,
SnAl _0.4 B _0.5 P _0.5 K _0.1 Mg _0.1 Ge _0.02 O _3.83 ,
SnAl _0.4 B _0.4 P _0.4 O _3.2 ,
SnAl _0.3 B _0.5 P _0.2 O _2.7 ,
SnAl _0.3 B _0.5 P _0.2 O _2.7 ,
SnAl _0.4 B _0.5 P _0.3 Ba _0.08 Mg _0.08 O _3.26 ,
SnAl _0.4 B _0.4 P _0.4 Ba _0.08 O _3.28 ,
SnAl _0.4 B _0.5 P _0.5 O _3.6 ,
SnAl _0.4 B _0.5 P _0.5 Mg _0.1 O _3.7 ,
SnAl _0.5 B _0.4 P _0.5 Mg _0.1 F _0.2 O _3.65 ,
SnB _0.5 P _0.5 Li _0.1 Mg _0.1 F _0.2 O _3.05 ,
SnB _0.5 P _0.5 K _0.1 Mg _0.1 F _0.2 O _3.05 ,
SnB _0.5 P _0.5 K _0.05 Mg _0.05 F _0.1 O _3.03 ,
SnB _0.5 P _0.5 K _0.05 Mg _0.1 F _0.2 O _3.03 ,
SnAl _0.4 B _0.5 P _0.5 Cs _0.1 Mg _0.1 F _0.2 O _3.65 ,
SnB _0.5 P _0.5 Cs _0.05 Mg _0.05 F _0.1 O _3.03 ,
SnB _0.5 P _0.5 Mg _0.1 F _0.1 O _3.05 ,
SnB _0.5 P _0.5 Mg _0.1 F _0.2 O _Three ,
SnB _0.5 P _0.5 Mg _0.1 F _0.06 O _3.07 ,
SnB _0.5 P _0.5 Mg _0.1 F _0.14 O _3.03 ,
SnPBa _0.08 O _3.58 ,
SnPK _0.1 O _3.55 ,
SnPK _0.05 Mg _0.05 O _3.58 ,
SnPCs _0.1 O _3.55 ,
SnPBa _0.08 F _0.08 O _3.54 ,
SnPK _0.1 Mg _0.1 F _0.2 O _3.55 ,
SnPK _0.05 Mg _0.05 F _0.1 O _3.53 ,
SnPCs _0.1 Mg _0.1 F _0.2 O _3.55 ,
SnPCs _0.05 Mg _0.05 F _0.1 O _3.53 ,
Sn _1.1 Al _0.4 B _0.2 P _0.6 Ba _0.08 F _0.08 O _3.54 ,
Sn _1.1 Al _0.4 B _0.2 P _0.6 Li _0.1 K _0.1 Ba _0.1 F _0.1 O _3.65 ,
Sn _1.1 Al _0.4 B _0.4 P _0.4 Ba _0.08 O _3.34 ,
Sn _1.1 Al _0.4 PCs _0.05 O _4.23 ,
Sn _1.1 Al _0.4 PK _0.04 O _4.23 ,
Sn _1.2 Al _0.5 B _0.3 P _0.4 Cs _0.2 O _3.5 ,
Sn _1.2 Al _0.4. B _0.2 P _0.6 Ba _0.08 O _3.68 ,
Sn _1.2 Al _0.4 B _0.2 P _0.6 Ba _0.08 F _0.08 O _3.64 ,
Sn _1.2 Al _0.4 B _0.2 P _0.6 Mg _0.04 Ba _0.04 O _3.68 ,
Sn _1.2 Al _0.4 B _0.3 P _0.5 Ba _0.08 O _3.58 ,
Sn _1.3 Al _0.3 B _0.3 P _0.4 Na _0.2 O _3.3 ,
Sn _1.3 Al _0.2 B _0.4 P _0.4 Ca _0.2 O _3.4 ,
Sn _1.3 Al _0.4 B _0.4 P _0.4 Ba _0.2 O _3.6 ,
Sn _1.4 Al _0.4 PK _0.2 O _4.6 ,
Sn _1.4 Al _0.2 Ba _0.1 PK _0.2 O _4.45 ,
Sn _1.4 Al _0.2 Ba _0.2 PK _0.2 O _4.6 ,
Sn _1.4 Al _0.4 Ba _0.2 PK _0.2 Ba _0.1 F _0.2 O _4.9 ,
Sn _1.4 Al _0.4 PK _0.3 O _4.65 ,
Sn _1.5 Al _0.2 PK _0.2 O _4.4 ,
Sn _1.5 Al _0.4 PK _0.1 O _4.65 ,
Sn _1.5 Al _0.4 PCs _0.05 O _4.63 ,
Sn _1.5 Al _0.4 PCs _0.05 Mg _0.1 F _0.2 O _4.63 ,
SnSi _0.5 Al _0.1 B ₀ . ₂ P _0.1 Ca _0.4 O _3.1 ,
SnSi _0.4 Al _0.2 B _0.4 O _2.7 ,
SnSi _0.5 Al _0.2 B _0.1 P _0.1 Mg _0.1 O _2.8 ,
SnSi _0.6 Al _0.2 B _0.2 O _2.8 ,
SnSi _0.5 Al _0.3 B _0.4 P _0.2 O _3.55 ,
SnSi _0.5 Al _0.3 B _0.4 P _0.5 O _4.30 ,
SnSi _0.6 Al _0.1 B _0.1 P _0.3 O _3.25 ,
SnSi _0.6 Al _0.1 B _0.1 P _0.1 Ba _0.2 O _2.95 ,
SnSi _0.6 Al _0.1 B _0.1 P _0.1 Ca _0.2 O _2.95 ,
SnSi _0.6 Al _0.4 B _0.2 Mg _0.1 O _3.2 ,
SnSi _0.6 Al _0.1 B _0.3 P _0.1 O _3.05 ,
SnSi _0.6 Al _0.2 Mg _0.2 O _2.7 ,
SnSi _0.6 Al _0.2 Ca _0.2 O _2.7 ,
SnSi _0.6 Al _0.2 P _0.2 O _Three ,
SnSi _0.6 B _0.2 P _0.2 O _Three ,
SnSi _0.8 Al _0.2 O _2.9 ,
SnSi _0.8 Al _0.3 B _0.2 P _0.2 O _3.85 ,
SnSi _0.8 B _0.2 O _2.9 ,
SnSi _0.8 Ba _0.2 O _2.8 ,
SnSi _0.8 Mg _0.2 O _2.8 ,
SnSi _0.8 Ca _0.2 O _2.8 ,
SnSi _0.8 P _0.2 O _3.1 ,
Sn _0.9 Mn _0.3 B _0.4 P _0.4 Ca _0.1 Rb _0.1 O _2.95 ,
Sn _0.9 Fe _0.3 B _0.4 P _0.4 Ca _0.1 Rb _0.1 O _2.95 ,
Sn _0.8 Pb _0.2 Ca _0.1 P _0.9 O _3.35 ,
Sn _0.3 Ge _0.7 Ba _0.1 P _0.9 O _3.35 ,
Sn _0.9 Mn _0.1 Mg _0.1 P _0.9 O _3.35 ,
Sn _0.2 Mn _0.8 Mg _0.1 P _0.9 O _3.35 ,
Sn _0.7 Pb _0.3 Ca _0.1 P _0.9 O _3.35 ,
Sn _0.2 Ge _0.8 Ba _0.1 P _0.9 O _3.35 .
[0051]
The negative electrode material is obtained by firing, for example. The chemical formula of the obtained compound can be calculated from an inductively coupled plasma (ICP) emission spectroscopic analysis method as a measurement method, and from a weight difference between powders before and after firing as a simple method.
[0052]
The amount of light metal inserted into the negative electrode material of the present invention may be close to the precipitation potential of the light metal, but for example, it is preferably 50 to 700 mol%, particularly preferably 100 to 600 mol% per negative electrode material. It is preferable that the release amount be larger than the insertion amount. The light metal insertion method is preferably an electrochemical, chemical or thermal method. The electrochemical method is preferably a method in which a light metal contained in the positive electrode active material is inserted electrochemically or a method in which the light metal or an alloy thereof is directly inserted electrochemically. Chemical methods include mixing with light metals, contact, or reacting with an organic metal such as butyllithium. Electrochemical methods and chemical methods are preferred. The light metal is particularly preferably lithium or lithium ion.
[0053]
In the present invention, the compounds represented by the general formulas (1) and (2) as described above are mainly used as the negative electrode material, so that the charge / discharge cycle characteristics are more excellent, the discharge voltage is high, and the capacity is safe. It is possible to obtain a nonaqueous electrolyte secondary battery having high performance and excellent high current characteristics. In the present invention, particularly excellent effects can be obtained when a compound containing Sn and having a valence of Sn of 2 is used as the negative electrode material. The valence of Sn can be determined by a chemical titration operation. For example, it can be analyzed by the method described on page 165 of Physics and Chemistry of Glasses Vol. 8 No. 4 (1967). It can also be determined from a night shift by Sn solid nuclear magnetic resonance (NMR) measurement. For example, in wide measurement, metal Sn (zero-valent Sn) is Sn (CH _Three ) _Four A peak appears in an extremely low magnetic field at around 7000 ppm with respect to SnO (= 2 valences), but near 100 ppm, SnO ₂ In (= 4 valences), it appears around -600 ppm. Thus, when it has the same ligand, since a night shift greatly depends on the valence of Sn which is a central metal, the valence can be determined at the peak position obtained by 119Sn-NMR measurement.
[0054]
Various compounds can be included in the negative electrode material of the present invention. For example, transition metals (Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, lanthanoid metals, Hf , Ta, W, Re, Os, Ir, Pt, Au, Hg) or a periodic table group 17 element (F, Cl). Moreover, you may contain the dopant of various compounds (for example, compound of Sb, In, Nb) which raises electronic conductivity. The amount of the compound to be added is preferably 0 to 20 mol%.
[0055]
As a method for synthesizing the composite oxide mainly composed of the oxides represented by the general formulas (1) and (2) in the present invention, either a firing method or a solution method can be employed.
[0056]
For example, the firing method will be described in detail. ₁ Compound, M ₂ Compound and M _Four Compound (M ₁ , M ₂ Are different from Si, Ge, Sn, Pb, P, B, Al, Sb, M _Four May be mixed with Mg, Ca, Sr, Ba) and fired. Examples of Sn compounds include SnO and SnO. ₂ , Sn ₂ O _Three , Sn _Three O _Four , Sn ₇ O ₁₃ ・ H ₂ O, Sn ₈ O ₁₅ , Stannous hydroxide, stannous oxyhydroxide, stannous acid, stannous oxalate, stannous phosphate, orthostannic acid, metastannic acid, parastannic acid, stannous fluoride, second fluorinated fluoride Examples thereof include tin, stannous chloride, stannic chloride, stannous pyrophosphate, tin phosphide, stannous sulfide, and stannic sulfide.
[0057]
Examples of Si compounds include SiO ₂ And organic silicon compounds such as SiO, tetramethylsilane and tetraethylsilane, alkoxysilane compounds such as tetramethoxysilane and tetraethoxysilane, and hydrosilane compounds such as trichlorohydrosilane.
[0058]
Examples of Ge compounds include GeO ₂ And alkoxy germanium compounds such as GeO, germanium tetramethoxide and germanium tetraethoxide.
[0059]
Examples of Pb compounds include PbO ₂ , PbO, Pb ₂ O _Three , Pb _Three O _Four , Lead nitrate, lead carbonate, lead formate, lead acetate, lead tetraacetate, lead tartrate, lead diethoxide, lead diisopropoxide and the like.
[0060]
Examples of the P compound include phosphorus pentoxide, phosphorus oxychloride, phosphorus pentachloride, phosphorus trichloride, phosphorus tribromide, trimethyl phosphate, triethyl phosphate, tripropyl phosphate, stannous pyrophosphate, boron phosphate and the like. Can be mentioned.
[0061]
Examples of the B compound include boron trioxide, boron trichloride, boron tribromide, boron carbide, boric acid, trimethyl borate, triethyl borate, tripropyl borate, tributyl borate, boron phosphide, boron phosphate and the like.
[0062]
Examples of the Al compound include aluminum oxide (α-alumina, β-alumina), aluminum silicate, aluminum tri-iso-propoxide, aluminum tellurite, aluminum chloride, aluminum boride, aluminum phosphide, aluminum phosphate, and lactic acid. Examples thereof include aluminum, aluminum borate, aluminum sulfide, aluminum sulfate, and aluminum boride.
[0063]
Examples of the Sb compound include diantimony trioxide and triphenylantimony.
[0064]
Examples of the Mg, Ca, Sr, and Ba compounds include respective oxide salts, hydroxide salts, carbonates, phosphates, sulfates, nitrates, and aluminum compounds.
[0065]
As firing conditions, the temperature rising rate is preferably 4 ° C. or more and 2000 ° C. or less, more preferably 6 ° C. or more and 2000 ° C. or less per minute. It is particularly preferably 10 ° C. or higher and 2000 ° C. or lower, and the firing temperature is preferably 250 ° C. or higher and 1500 ° C. or lower, more preferably 350 ° C. or higher and 1500 ° C. or lower, and particularly preferably 500 ° C. or higher and 1500 ° C. or lower. The firing time is preferably 0.01 hours to 100 hours, more preferably 0.5 hours to 70 hours, and particularly preferably 1 hour to 20 hours, and the temperature is lowered. The speed is over 2 ° C / min 10 ⁷ It is preferable that the temperature is not higher than ° C, and more preferably 4 ° C or higher and ⁷ ° C or lower, particularly preferably 6 ° C or higher and 10 ° C or lower. ⁷ ° C or lower, particularly preferably 10 ° C or higher and 10 ° C or lower. ⁷ It is below ℃.
[0066]
The rate of temperature increase in the present invention is the average rate of temperature rise from “50% of the firing temperature (indicated in ° C.)” to “80% of the firing temperature (indicated in ° C.)”. It is the average rate of temperature drop from reaching “80% of the firing temperature (indicated by ° C.)” to “50% of the firing temperature (expressed in ° C)”
[0067]
The temperature lowering may be cooled in a firing furnace, or taken out of the firing furnace and cooled, for example, in water. In addition, a super rapid cooling method such as a gun method, a Hammer-Anvil method, a slap method, a gas atomizing method, a plasma spray method, a centrifugal quenching method, or a melt drag method described on page 217 of ceramic processing (Gihodo Publishing 1987) can also be used. Moreover, you may cool using the single-roller method and double roller method of New Glass Handbook (Maruzen 1991) p.172. In the case of a material that melts during firing, the fired product may be continuously taken out while supplying raw materials during firing. In the case of a material that melts during firing, it is preferable to stir the melt.
[0068]
The firing gas atmosphere is preferably an atmosphere having an oxygen content of 5% by volume or less, and more preferably an inert gas atmosphere. Examples of the inert gas include nitrogen, argon, helium, krypton, and xenon.
[0069]
The average particle size of the compounds represented by the general formulas (1) and (2) used in the present invention is preferably 0.1 to 60 μm, particularly preferably 1.0 to 30 μm, and further preferably 2.0 to 20 μm. To obtain a predetermined particle size, a well-known pulverizer or classifier is used. For example, a mortar, a ball mill, a sand mill, a vibrating ball mill, a satellite ball mill, a planetary ball mill, a swirling air flow type jet mill, a sieve, or the like is used. When pulverizing, wet pulverization in the presence of water or an organic solvent such as methanol can be performed as necessary. In order to obtain a desired particle size, classification is preferably performed. The classification method is not particularly limited, and a sieve, an air classifier, or the like can be used as necessary. Classification can be used both dry and wet.
[0070]
More preferable lithium-containing transition metal oxide positive electrode materials used in the present invention include lithium compounds / transition metal compounds (wherein transition metals are Ti, V, Cr, Mn, Fe, Co, Ni, Mo, W). It is preferable to mix and synthesize so that the total molar ratio of at least one selected is 0.3 to 2.2. A particularly preferable lithium-containing transition metal oxide positive electrode material used in the present invention is a lithium compound / transition metal compound (where the transition metal is at least one selected from V, Cr, Mn, Fe, Co, and Ni). It is preferable to synthesize by mixing so that the total molar ratio of is 0.3 to 2.2.
[0071]
A particularly preferable lithium-containing transition metal oxide positive electrode material used in the present invention is Lix QOy (where Q is a transition metal mainly containing at least one of Co, Mn, Ni, V, and Fe), x = 0. 2-1.2 and y = 1.4-3) are preferred. As Q, in addition to the transition metal, Al, Ga, In, Ge, Sn, Pb, Sb, Bi, Si, P, B, or the like may be mixed. The mixing amount is preferably 0 to 30 mol% with respect to the transition metal.
[0072]
As a more preferable lithium-containing metal oxide positive electrode material used in the present invention, Li _x CoO ₂ , Li _x NiO ₂ , Li _x MnO ₂ , Li _x Co _a Ni _1-a O ₂ , Li _x Co _b V _1-b O _z , Li _x Co _b Fe _1-b O ₂ , Li _x Mn ₂ O _Four , Li _x Mn _c Co _2-c O _Four , Li _x Mn _c Ni _2-c O _Four , Li _x Mn _c V _2-c O _Four , Li _x Mn _c Fe _2-c O _Four (Where x = 0.02 to 1.2, a = 0.1 to 0.9, b = 0.8 to 0.98, c = 1.6 to 1.96, z = 2.1-2. .3).
[0073]
As the most preferable lithium-containing transition metal oxide positive electrode material used in the present invention, Li _x CoO ₂ , Li _x NiO ₂ , Li _x MnO ₂ , Li _x Co _a Ni _1-a O ₂ , Li _x Mn ₂ O _Four , Li _x Co _b V _1-b O _z (Where x = 0.02 to 1.2, a = 0.1 to 0.9, b = 0.9 to 0.98, z = 2.01 to 2.3).
[0074]
Here, said x value is a value before the start of charging / discharging, and it increases / decreases by charging / discharging.
The conductive carbon compound that can be used in the present invention may be any electronic conductive material that does not cause a chemical change in the battery. Specific examples include natural graphite such as scaly graphite, scaly graphite and earthy graphite, high-temperature fired bodies such as petroleum coke, coal coke, celluloses, saccharides and mesophase pitch, and graphite such as artificial graphite such as vapor-grown graphite. And carbon blacks such as acetylene black, furnace black, ketjen black, channel black, lamp black and thermal black, asphalt pitch, coal tar, activated carbon, mesofuse pitch, polyacene and the like. Of these, graphite and carbon black are preferred.
[0075]
As conductive agents other than carbon, conductive fibers such as metal fibers, metal powders such as copper, nickel, aluminum and silver, conductive whiskers such as zinc oxide and potassium titanate, and conductive metals such as titanium oxide An oxide or the like can be contained alone or a mixture thereof as required.
[0076]
The amount of the conductive agent added to the mixture layer is preferably 6 to 50% by weight, particularly 6 to 30% by weight, based on the negative electrode material or the positive electrode material. In the case of carbon or graphite, the content is particularly preferably 6 to 20% by weight.
[0077]
As a binder for holding the electrode mixture used in the present invention, a polysaccharide, a thermoplastic resin, and a polymer having rubber elasticity, or a mixture thereof can be used. Preferred binders include starch, carboxymethyl cellulose, cellulose, diacetyl cellulose, methyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, sodium alginate, polyacrylic acid, polyacrylic acid Na, polyvinyl phenol, polyvinyl methyl ether, polyvinyl alcohol, polyvinyl pyrrolidone. , Polyacrylamide, polyhydroxy (meth) acrylate, water-soluble polymers such as styrene-maleic acid copolymer, polyvinyl chloride, polytetrafluoroethylene, polyvinylidene fluoride, tetrafluoroethylene-hexafluoropropylene copolymer, vinylidene fluoride -Tetrafluoroethylene-hexafluoropropylene copolymer, polyethylene, polypropylene, ethylene-propylene (Meth) acrylic acid ester copolymer containing (meth) acrylic acid ester such as di-diene terpolymer (EPDM), sulfonated EPDM, polyvinyl acetal resin, methyl methacrylate, 2-ethylhexyl acrylate, (meth) acrylic Acid ester-acrylonitrile copolymer, polyvinyl ester copolymer containing vinyl ester such as vinyl acetate, styrene-butadiene copolymer, acrylonitrile-butadiene copolymer, polybutadiene, neoprene rubber, fluoro rubber, polyethylene oxide, polyester polyurethane Resin, polyether polyurethane resin, polycarbonate polyurethane resin, polyester resin, phenol resin, epoxy resin emulsion (latex) or suspension It can be cited. In particular, polyacrylate ester latex, carboxymethyl cellulose, polytetrafluoroethylene, and polyvinylidene fluoride are preferable.
[0078]
These binders can be used alone or in combination. If the amount of the binder added is small, the holding power / cohesive force of the electrode mixture is weak and the cycleability is poor, and if it is too large, the electrode volume increases and the capacity per unit electrode or unit weight decreases. The conductivity decreases and the capacity decreases. The addition amount of the binder is not particularly limited, but is preferably 1 to 30% by weight, and particularly preferably 2 to 10% by weight.
[0079]
The negative electrode mixture or the positive electrode mixture paste of the present invention is preferably adjusted in an aqueous system.
[0080]
The mixture paste is prepared by first mixing an active material and a conductive agent, adding a binder (suspension of resin powder or emulsion (latex)) and water, kneading and mixing, followed by a mixer, It can be carried out by dispersing with a stirring mixer or disperser such as a homogenizer, dissolver, planetary mixer, paint shaker or sand mill.
[0081]
The adjusted positive electrode active material and negative electrode active material mixture paste are mainly applied (coated), dried and compressed on the current collector. Application can be performed by various methods, for example, reverse roll method, direct roll method, blade method, knife method, extrusion method, curtain method, gravure method, bar method, dipping method and squeeze method. I can do it. A blade method, a knife method and an extrusion method are preferred. The application is preferably performed at a speed of 0.1 to 100 m / min. Under the present circumstances, the surface state of a favorable coating layer can be obtained by selecting the said application | coating method according to the liquid physical property of a mixture paste, and drying property. The thickness, length, and width of the coating layer are determined by the size of the battery, and the thickness of the coating layer is particularly preferably 1 to 2000 μm in a compressed state after drying.
[0082]
As a drying or dehydration method for removing moisture from pellets and sheets, a generally adopted method can be used, and hot air, vacuum, infrared rays, far infrared rays, electron beams and low-humidity air are used alone or in combination. I can do it. 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 500 ppm or less for each of the positive electrode mixture, the negative electrode mixture and the electrolyte from the viewpoint of charge / discharge cycle properties.
[0083]
For the compression of the sheet-like electrode mixture, a generally adopted pressing method can be used, but a mold pressing method and a calendar pressing method are particularly preferable. The press pressure is not particularly limited, but is 10 kg / cm. ² ~ 3t / cm ² Is preferred. The press speed of the calendar press method is preferably 0.1 to 50 m / min. The pressing temperature is preferably room temperature to 200 ° C.
[0084]
The positive electrode and negative electrode support or current collector that can be used in the present invention is made of aluminum, stainless steel, nickel, titanium, or an alloy thereof for the positive electrode, and copper, stainless steel, nickel, titanium for the negative electrode. Or an alloy of these, and the form is foil, expanded metal, punching metal, or wire mesh. In particular, an aluminum foil is preferable for the positive electrode and a copper foil is preferable for the negative electrode.
[0085]
The separator that can be used in the present invention is only required to be an insulating thin film having a large ion permeability, a predetermined mechanical strength, and an olefin polymer, a fluorine polymer, a cellulose polymer, polyimide, nylon, Glass fiber and alumina fiber are used, and as a form, a nonwoven fabric, a woven fabric, and a microporous film are used. In particular, the material is preferably polypropylene, polyethylene, a mixture of polypropylene and polyethylene, a mixture of polypropylene and Teflon, or a mixture of polyethylene and Teflon, and the form is preferably a microporous film. In particular, a microporous film having a pore diameter of 0.01 to 1 μm and a thickness of 5 to 50 μm is preferable.
[0086]
FIG. 1 shows a cross section of a cylindrical battery. The shape of the battery can be applied to any of buttons, coins, sheets, cylinders, and corners. The battery is formed by inserting electrode sheets 4 and 5 wound together with pellets, sheets or separators 3 into the battery can 2, electrically connecting the can and the electrode, injecting and sealing the electrolyte 6. An inner lid body 10 provided with a ring 11 is fitted into the upper opening of the battery can 2 via the polypropylene gasket 1 to expose the positive electrode cap 8 serving also as a positive electrode terminal. At this time, the safety valve 7 (explosion-proof valve body) can be used as a sealing plate. Furthermore, it is preferable to use the PTC element 9 in order to guarantee the safety of the battery.
[0087]
The bottomed battery outer can which can be used in the present invention is a steel plate, stainless steel plate (SUS304, SUS304L, SUS304N, SUS316, SUS316L, SUS430, SUS444, etc.) plated with nickel, and a nickel plated stainless steel plate (same as above). , Aluminum or an alloy thereof, nickel, titanium, and copper, and the shapes are a true circular cylinder, an elliptical cylinder, a square cylinder, and a rectangular cylinder. In particular, when the outer can also serves as the negative electrode terminal, a stainless steel plate and a nickel-plated steel plate are preferable, and when the outer can also serves as the positive electrode terminal, a stainless steel plate, aluminum, or an alloy thereof is preferable.
[0088]
The sheet-like mixture electrode is wound or folded and inserted into a can, the can and the sheet are electrically connected, an electrolyte is injected, and a sealing plate is used to form a battery can. At this time, the safety valve can be used as a sealing plate. In addition to the safety valve, various conventionally known safety elements may be provided. For example, a fuse, bimetal, PTC element, or the like is used as the overcurrent prevention element. In addition to the safety valve, as a countermeasure against the increase in internal pressure of the battery can, a method of cutting the battery can, a gasket cracking method, or a sealing plate cracking method can be used. Moreover, you may equip the charger with the circuit incorporating the countermeasure against overcharge or overdischarge.
[0089]
The entire amount of the electrolyte may be injected at one time, but it is preferable to carry out in two or more stages. When the injection is divided into two or more stages, each liquid may have the same composition, but a different composition (for example, a nonaqueous solvent or a nonaqueous solvent having a viscosity higher than that of the solvent after injecting a solution in which a lithium salt is dissolved in the nonaqueous solvent). Or a solution in which a lithium salt is dissolved in a solvent or a nonaqueous solvent may be injected). Further, in order to shorten the electrolyte injection time, the battery can may be decompressed (preferably 500 to 1 torr, more preferably 400 to 10 torr), or centrifugal force or ultrasonic waves may be applied to the battery can. .
[0090]
For the can and the lead plate, a metal or an alloy having electrical conductivity can be used. For example, metals such as iron, nickel, titanium, chromium, molybdenum, copper, aluminum, or alloys thereof are used. A known method (eg, direct current or alternating current electric welding, laser welding, ultrasonic welding) can be used as a method for welding the cap, can, sheet, and lead plate. As the sealing agent for sealing, a conventionally known compound or mixture such as asphalt can be used.
[0091]
Gaskets that can be used in the present invention are olefin polymers, fluoropolymers, cellulosic polymers, polyimides, and polyamides as materials. Olefin polymers are preferred from the viewpoint of organic solvent resistance and low moisture permeability, and are mainly composed of propylene. Polymers are preferred. Furthermore, a block copolymer of propylene and ethylene is preferable.
[0092]
The battery of the present invention is covered with an exterior material as necessary. Examples of the exterior material include a heat-shrinkable tube, an adhesive tape, a metal film, paper, cloth, paint, and a plastic case. Further, at least a part of the exterior may be provided with a portion that changes color by heat so that the heat history during use can be known.
[0093]
A plurality of the batteries of the present invention are assembled in series and / or in parallel as needed, and stored in a battery pack. In addition to safety elements such as positive temperature coefficient resistors, temperature fuses, fuses and / or current interrupting elements, the battery pack also requires safety circuits (monitoring the voltage, temperature, current, etc. of each battery and / or the entire battery pack) In this case, a circuit having a function of interrupting current may be provided. In addition to the positive and negative terminals of the entire assembled battery, the battery pack should be provided with the positive and negative terminals of each battery, the entire assembled battery, the temperature detection terminal of each battery, the current detection terminal of the entire assembled battery, etc. as external terminals. You can also. The battery pack may incorporate a voltage conversion circuit (such as a DC-DC converter). The connection of each battery may be fixed by welding a lead plate, or may be fixed so that it can be easily attached and detached with a socket or the like. Further, the battery pack may be provided with display functions such as the remaining battery capacity, the presence / absence of charging, and the number of uses.
[0094]
The battery of the present invention is used in various devices. In particular, video movies, portable video decks with built-in monitors, movie cameras with built-in monitors, compact cameras, single-lens reflex cameras, film with lenses, notebook computers, notebook word processors, electronic notebooks, mobile phones, cordless phones, shavings, power tools, It is preferably used for electric mixers, automobiles and the like.
[0095]
【Example】
Hereinafter, the present invention will be described in more detail with specific examples. However, the present invention is not limited to the examples unless it exceeds the gist of the invention.
[0096]
[Preparation Example of Positive Electrode Mixture Paste; Examples, Comparative Examples]
Cathode active material; LiCoO ₂ Was made as follows. A mixture of lithium carbonate and tricobalt tetroxide in a molar ratio of 3: 2 was placed in an alumina crucible, heated to 750 ° C. at 2 ° C./min in the air and calcined for 4 hours, then 2 min / min. The temperature was raised to 900 ° C. at a rate of 0 ° C., calcined at that temperature for 8 hours, and then pulverized to form LiCoO ₂ A particle powder was prepared. Created LiCoO ₂ The particles have a center particle size of 5 μm, and when the washing product 50 g is dispersed in 100 ml of water, the conductivity of the dispersion is 0.6 mS / m, the pH is 10.1, the specific surface area by the nitrogen adsorption method is 0.42 m ² / G. This LiCoO ₂ 200 g of particles and 10 g of acetylene black were mixed with a homogenizer, followed by 8 g of an aqueous dispersion of a copolymer of 2-ethylhexyl acrylate, acrylic acid and acrylonitrile (solid content concentration 50% by weight) as a binder, concentration 2 A 60% by weight aqueous solution of carboxymethylcellulose was added and kneaded and mixed, 50 g of water was further added, and the mixture was stirred and mixed with a homogenizer to prepare a positive electrode mixture paste.
[0097]
[Example of making negative electrode mixture paste]
Negative electrode active material; SnGe _0.1 B _0.5 P _0.58 Mg _0.1 K _0.1 O _3.35 (6.7 g of tin monoxide, 10.3 g of tin pyrophosphate, 1.7 g of diboron trioxide, 0.7 g of potassium carbonate, 0.4 g of magnesium oxide, and 1.0 g of germanium dioxide were dry-mixed and placed in an alumina crucible. The temperature was raised to 1000 ° C. at 15 ° C./min in an argon atmosphere, baked at 1100 ° C. for 12 hours, cooled to room temperature at 10 ° C./min, collected from the baking furnace, and pulverized with a jet mill (In the X-ray diffraction method using CuKα ray with an average particle size of 4.5 μm, it has a broad peak having an apex in the vicinity of 28 ° with a 2θ value, and a crystal with a 2θ value of 40 ° to 70 ° 200 g) and 30 g of a conductive agent (artificial graphite) were mixed with a homogenizer, and 50 g of a carboxymethyl cellulose aqueous solution having a concentration of 2% by weight as a binder, A mixture of 10 g of polyvinylidene fluoride added and mixed with 30 g of water and kneaded to prepare a negative electrode mixture paste.
[0098]
[Creation of positive and negative electrode sheets]
The positive electrode mixture paste prepared above was applied to both sides of an aluminum foil current collector having a thickness of 30 μm with a blade coater at a coating amount of 400 g / m. ² Then, the coated sheet was applied so that the thickness of the compressed sheet was 280 μm, dried, and then compression-molded with a roller press machine and cut into a predetermined size to prepare a belt-like positive electrode sheet. Furthermore, it was sufficiently dehydrated and dried with a far-infrared heater in a dry box (dew point: dry air of −50 ° C. or lower) to prepare a positive electrode sheet.
[0099]
Similarly, a negative electrode mixture paste was applied to a 20 μm copper foil current collector, and the application amount was 70 g / m in the same manner as in the preparation of the positive electrode sheet. ² A negative electrode sheet having a thickness of 90 μm after compression was prepared.
[0100]
[Example of electrolyte production]
Under an argon atmosphere, 65.3 g of diethyl carbonate was placed in a 200 cc narrow-neck polypropylene container, and 22.2 g of ethylene carbonate was dissolved little by little while taking care not to exceed a liquid temperature of 30 ° C. Next, 0.4 g of LiBF _Four 12.1 g LiPF ₆ The solution was dissolved in a small amount in the polypropylene container in order, taking care that the liquid temperature did not exceed 30 ° C.
[0101]
The obtained electrolyte was a colorless transparent liquid having a specific gravity of 1.135. Moisture was 18 ppm (measured with a trade name MKC-210, Karl Fischer moisture measuring device, manufactured by Kyoto Electronics), free acid content was 24 ppm (measured by neutralization titration with 0.1 N NaOH aqueous solution using bromthymol blue as an indicator) )Met.
[0102]
[Cylinder battery creation example]
As shown in FIG. 1, a positive electrode sheet 5, a microporous polypropylene film separator, a negative electrode sheet 4, and a separator 3 were laminated in this order and wound in a spiral shape. The wound body was housed in an iron-bottomed cylindrical battery can 2 made of iron and also plated with nickel, which also serves as a negative electrode terminal. Further, the electrolyte 6 was injected into the battery can 2. A battery lid 8 having a positive electrode terminal, a PCT element 9, an explosion-proof valve body 7 and the like were stacked and caulked through the gasket 1 to produce a cylindrical battery.
[0103]
(Example 1)
A stainless steel container having a volume of 0.5 liter was filled with 0.2 liter of non-aqueous electrolyte, and the remaining volume was filled with air having a dew point of −55 ° C. and a temperature of 20 ° C. The container was shaken for 180 seconds with an amplitude of 5 centimeters and a frequency of 5 Hz, and injected into the battery after 5 minutes.
[0104]
(Example 2)
A stainless steel container having a volume of 1 liter was filled with 0.5 liter of nonaqueous electrolyte, and the remaining volume was filled with air having a dew point of −53 ° C. A 5 cm long stirring blade is installed in the center of the container, and a 3 cm wide baffle plate is installed on the wall of the container. The stirring blade is rotated at 300 rpm for 60 seconds, and the electrolyte is shaken, and injected into the battery after 5 minutes. did.
[0105]
(Example 3)
Fill a 0.5 liter stainless steel container with 0.3 liter of non-aqueous electrolyte, open the top lid, and blow air air with a wind speed of 3 meters dew point -57 ° C. for 1 hour and inject it into the battery after 10 minutes. .
[0106]
(Example 4)
A non-aqueous electrolyte of 0.4 liter is placed in a 0.5 liter PFA gas cleaning bottle (having a ball filter with a diameter of 25 mm inside and a ball filter pore diameter of 10 μm), and the ball filter has a dew point of −50 ° C. and a temperature of 20 ° C. Was bubbled at a rate of 2 liters / minute for 3 minutes and injected into the battery after 5 minutes.
[0107]
(Example 5)
A battery was prepared in the same manner as in Example 4 except that the dew point of air was −30 ° C.
[0108]
(Example 6)
A battery was prepared in the same manner as in Example 4 except that the dew point of air was −40 ° C.
[0109]
(Example 7)
A battery was prepared in the same manner as in Example 4 except that the temperature of the nonaqueous electrolyte and air was cooled to 5 ° C.
[0110]
(Example 8)
A battery was prepared in the same manner as in Example 4 except that the nonaqueous electrolyte was injected into the battery 2 hours after the air blowing treatment.
[0111]
(Comparative Example 1)
A battery was prepared using a non-aqueous electrolyte that was not air blown.
[0112]
(Comparative Example 2)
A battery was prepared in the same manner as in Example 4 except that the dew point of air was −20 ° C.
[0113]
For the battery prepared by the above method, the current density is 5 mA / cm. ² The battery was charged and discharged under the conditions of a charge end voltage of 4.1 V and a discharge end voltage of 2.8 V, and the cycle life was determined.
[0114]
Table 1 shows the cycle characteristics of each battery (ratio of the 300th capacity with respect to the first charge / discharge).
[0115]
[Table 1]
Example 1 85%
Example 2 84%
Example 3 83%
Example 4 85%
Example 5 78%
Example 6 80%
Example 7 87%
Example 8 80%
Comparative Example 1 70%
Comparative Example 2 65%
[0116]
As is clear from these Examples compared with Comparative Example 1, the use of an air blown electrolyte can improve the charge / discharge cycle characteristics of a non-aqueous electrolyte secondary battery having a large discharge capacity.
[0117]
From the result of Example 5 in which the dew point of air is −30 ° C. (78%) and the result of Comparative Example 2 in which the air dew point is −20 ° C. (65%), the dew point of air is −30 ° C. or less. preferable. However, there will be little need to lower the dew point below -80 ° C. It is difficult to reduce the dew point below −80 ° C. in terms of production cost. Further, since the water content is several ppm, there is almost no substantial difference even if the dew point is lower than -80 ° C.
[0118]
Also, within 1 hour after the air blowing treatment, the result of Example 4 (85%) injected into the battery 5 minutes after the air blowing treatment and the result of Example 8 (80%) injected into the battery 2 hours after the treatment. It is preferable to inject a non-aqueous electrolyte into the battery.
[0119]
A better result is obtained when the air temperature is 5 ° C in Example 7 than 20 ° C in Example 4. The temperature of the air will preferably be from -10 ° C to 20 ° C.
[0120]
In Example 3, an air wind with a wind speed of 3 m was blown for 1 hour, but good results would be obtained even if an air wind with a wind speed of 0.1 m to 10 m was blown for 6 hours to 0.1 hour.
[0121]
【The invention's effect】
By using an electrolyte that has been subjected to air blowing treatment as in the present invention, it is possible to obtain a nonaqueous electrolyte secondary battery that has a small discharge capacity due to repeated charge and discharge.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a cylinder type battery used in Examples.
[Explanation of symbols]
1 Polypropylene gasket
2 Negative electrode can (battery can) that also serves as the negative electrode terminal
3 Separator
4 Negative electrode sheet
5 Positive electrode sheet
6 Non-aqueous electrolyte
7 Explosion-proof valve body
8 Positive cap that doubles as positive terminal
9 PTC element
10 Internal lid
11 rings

Claims (8)

  A positive electrode containing a material capable of reversibly occluding and releasing lithium, and containing three or more kinds of atoms selected from periodic table 1, 2, 13, 14, 15 atoms, mainly amorphous chalcogen compounds and / or non In a nonaqueous electrolyte secondary battery having a negative electrode made of a crystalline oxide, a nonaqueous electrolyte containing a lithium salt, and a separator, the nonaqueous electrolyte is blown with air having a dew point of −80 ° C. to −30 ° C. A nonaqueous electrolyte secondary battery characterized by being treated. The nonaqueous electrolyte secondary battery according to claim 1, wherein at least one of the negative electrode materials is represented by the general formula (1).
M1 M2pM4qM6r General formula (1)
(In the formula, M1 and M2 are different and are at least one selected from Si, Ge, Sn, Pb, P, B, Al, and Sb, and M4 is selected from Li, K, Na, Cs, Mg, Ca, Sr, and Ba. At least one selected from the group consisting of O, S and Te, p and q each represent a number from 0.001 to 10, and r represents a number from 1.00 to 50.)   A positive electrode containing a material capable of reversibly occluding and releasing lithium, and containing three or more kinds of atoms selected from periodic table 1, 2, 13, 14, 15 atoms, mainly amorphous chalcogen compounds and / or non A method for producing a non-aqueous electrolyte secondary battery comprising a negative electrode comprising a crystalline oxide, a non-aqueous electrolyte containing a lithium salt, and a separator, wherein the dew point is applied to the non-aqueous electrolyte before the non-aqueous electrolyte is injected into the battery. A method for producing a non-aqueous electrolyte secondary battery, wherein an air blowing process is performed using air at -80 ° C to -30 ° C.   The method for producing a non-aqueous electrolyte secondary battery according to claim 3, wherein the air blowing treatment is performed by placing air and a non-aqueous electrolyte in a container and shaking the non-aqueous electrolyte in sufficient contact with air.   The non-aqueous electrolyte 2 according to claim 3, wherein the air blowing treatment is performed by blowing air at a wind speed of 0.1 to 10 meters on the surface of the non-aqueous electrolyte for 0.1 to 6 hours. A method for manufacturing a secondary battery.   The method for producing a non-aqueous electrolyte secondary battery according to claim 3, wherein the air blowing treatment is performed by blowing air from a nozzle into the non-aqueous electrolyte.   The method for manufacturing a non-aqueous secondary battery according to claim 3, wherein the air blowing process is performed at a temperature of −10 ° C. to 20 ° C. 7.   The method for producing a non-aqueous secondary battery according to any one of claims 3 to 7, wherein the air blowing treatment is performed within 1 hour before the non-aqueous electrolyte is injected into the battery.

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