JP2007128723A - Battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a battery capable of enhancing charge/discharge efficiency even when a charging voltage is set to a value higher than 4.2 V. <P>SOLUTION: The battery includes a wound electrode body 20 in which a positive electrode 21 and a negative electrode 22 are wound with a separator 23 in between. The open circuit voltage when fully charged falls within a range of 4.25 V to 6.00 V inclusive. The positive electrode 21 contains a lithium composite oxide such as LiCoO<SB>2</SB>and, as required, a lithium composite oxide such as LiNi<SB>0.33</SB>Co<SB>0.33</SB>Mn<SB>0.33</SB>O<SB>2</SB>, LiNi<SB>0.5</SB>Co<SB>0.2</SB>Mn<SB>0.3</SB>O<SB>2</SB>F<SB>0.01</SB>, LiNi<SB>0.5</SB>Mn<SB>0.5</SB>O<SB>2</SB>or LiMn<SB>2</SB>O<SB>4</SB>, or a lithium composite phosphate such as LiFePO<SB>4</SB>. The separator 23 is impregnated with an electrolytic solution. The electrolytic solution contains vinylene carbonate, LiPF<SB>6</SB>, and at least one of LiBF<SB>4</SB>and lithium bis-oxalate borate. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a battery having an open circuit voltage of 4.25 V or more in a fully charged state per pair of positive electrode and negative electrode.

  With the remarkable development of portable electronic technology in recent years, electronic devices such as mobile phones and notebook computers have begun to be recognized as fundamental technologies that support an advanced information society. In addition, research and development related to the enhancement of the functions of these electronic devices have been energetically advanced, and the power consumption of these electronic devices has been increasing proportionally. On the other hand, these electronic devices are required to be driven for a long time, and a high energy density of a secondary battery as a driving power source has been inevitably desired. In addition, it has been desired to extend the cycle life for environmental reasons.

  From the standpoint of the occupied volume and mass of the battery built in the electronic device, the higher the energy density of the battery, the better. At present, since lithium ion secondary batteries have an excellent energy density, they have been built into most devices.

In such a lithium ion secondary battery, for example, LiPF ₆ is used as an electrolyte salt in order to improve the ionic conductivity of the electrolytic solution. However, PF ₅ generated by dissociation of LiPF ₆ decomposes, for example, a carbonic acid ester used as a solvent, resulting in a decrease in battery capacity. Therefore, by adding LiBF _4, BF ₄ ^- anions to produce a, it has been proposed to suppress the decomposition of LiPF ₆ (e.g., see Patent Document 1). Further, it has been proposed that a vinylene carbonate derivative is further mixed to form a film on the negative electrode to suppress the reductive decomposition of LiBF ₄ and improve cycle characteristics (see, for example, Patent Document 2). Further, it is proposed to limit the concentration of LiPF ₆ and LiBF ₄ and to improve the discharge characteristics after continuous charging by using cyclic carbonate, chain carbonate and vinylene carbonate as the main components as solvents. (For example, see Patent Document 3). Furthermore, it has been proposed to improve the cycle characteristics by using LiPF ₆ and lithium bisoxalate borate to make the current distribution uniform and reduce the overvoltage at the end on the positive electrode side (for example, Patent Documents). 4).

  By the way, in a lithium ion secondary battery, lithium cobaltate is normally used for the positive electrode and a carbon material is used for the negative electrode, and the operating voltage is used in the range of 4.2V to 2.5V. In the unit cell, the terminal voltage can be increased to 4.2 V largely due to excellent electrochemical stability such as a non-aqueous electrolyte and a separator.

On the other hand, in a conventional lithium ion secondary battery operating at a maximum of 4.2 V, the positive electrode active material such as lithium cobaltate used for the positive electrode only uses about 60% of its theoretical capacity. Absent. For this reason, it is possible in principle to utilize the remaining capacity by further increasing the charging pressure. In fact, it is known that high energy density is manifested by setting the voltage during charging to 4.25 V or more (see, for example, Patent Document 5).
JP-A-8-64237 JP 2002-25608 A JP 2005-32701 A JP 2002-175836 A International Publication No. WO03 / 019713 Pamphlet

  However, in a battery in which the charging voltage is set to exceed 4.2 V, the oxidizing atmosphere particularly in the vicinity of the positive electrode surface is strengthened. As a result, the electrolytic solution that physically contacts the positive electrode is oxidatively decomposed and the charge / discharge efficiency is lowered. Such a problem is not sufficient even when an electrolytic solution containing the above-described electrolyte salt or solvent is used, and is particularly remarkable at high temperatures.

  The present invention has been made in view of such problems, and an object thereof is to provide a battery capable of improving charge / discharge efficiency even when a charge voltage is set to exceed 4.2V.

A first battery according to the present invention is provided with an electrolyte together with a positive electrode and a negative electrode, and an open circuit voltage in a fully charged state per pair of the positive electrode and the negative electrode is within a range of 4.25V to 6.00V. A lithium composite oxide expressed by the average composition shown in Chemical Formula 1, a lithium composite oxide expressed by the average composition shown in Chemical Formula 2, a lithium composite oxide expressed by the average composition shown in Chemical Formula 3, Including at least one member selected from the group consisting of a lithium composite oxide represented by the average composition shown in Chemical formula 4 and a lithium composite phosphate shown in Chemical formula 5, and the electrolyte solution is vinylene carbonate, LiPF ₆ , Lithium bisoxalate borate.
(Chemical formula 1)
Li _r Co _(1-s) M3 _s O _{(2-t) Fu}
(In the formula, M3 is nickel (Ni), manganese (Mn), magnesium (Mg), aluminum (Al), boron (B), titanium (Ti), vanadium (V), chromium (Cr), iron (Fe ), Copper (Cu), zinc (Zn), zirconium (Zr), molybdenum (Mo), tin (Sn), calcium (Ca), strontium (Sr), and tungsten (W). R, s, t, and u are ranges of 0.8 ≦ r ≦ 1.2, 0 ≦ s <0.5, −0.1 ≦ t ≦ 0.2, and 0 ≦ u ≦ 0.1. Is the value in.)
(Chemical formula 2)
Li _f Mn _(1-gh) Ni _g M1 _h O _(2-j) F _k
(In the formula, M1 is at least one selected from the group consisting of cobalt (Co), magnesium, aluminum, boron, titanium, vanadium, chromium, iron, copper, zinc, zirconium, molybdenum, tin, calcium, strontium, and tungsten. F, g, h, j and k are 0.8 ≦ f ≦ 1.2, 0 <g <0.5, 0 ≦ h ≦ 0.5, g + h <1, −0.1 ≦ j. ≦ 0.2 and 0 ≦ k ≦ 0.1.)
(Chemical formula 3)
Li _m Ni _(1-n) M2 _n O _(2-p) F _q
(Wherein M2 represents at least one selected from the group consisting of cobalt, manganese, magnesium, aluminum, boron, titanium, vanadium, chromium, iron, copper, zinc, zirconium, molybdenum, tin, calcium, strontium, and tungsten. M, n, p and q are 0.8 ≦ m ≦ 1.2, 0.005 ≦ n ≦ 0.5, −0.1 ≦ p ≦ 0.2, 0 ≦ q ≦ 0.1. (The value is within the range.)
(Chemical formula 4)
Li _v Mn _2-w M4 _w O _x F _y
(In the formula, M4 represents at least one selected from the group consisting of cobalt, nickel, magnesium, aluminum, boron, titanium, vanadium, chromium, iron, copper, zinc, molybdenum, tin, calcium, strontium, and tungsten. v, w, x and y are values in the range of 0.9 ≦ v ≦ 1.1, 0 ≦ w ≦ 0.6, 3.7 ≦ x ≦ 4.1, 0 ≦ y ≦ 0.1. is there.)
(Chemical formula 5)
Li _z M5PO ₄
(Wherein M5 is at least one selected from the group consisting of cobalt, manganese, iron, nickel, magnesium, aluminum, boron, titanium, vanadium, niobium (Nb), copper, zinc, molybdenum, calcium, strontium, tungsten and zirconium. Represents one type, z is a value in the range of 0.9 ≦ z ≦ 1.1.)

A second battery according to the present invention includes an electrolyte solution together with a positive electrode and a negative electrode, and an open circuit voltage in a fully charged state per pair of the positive electrode and the negative electrode is within a range of 4.25V to 6.00V. Yes, the positive electrode is a lithium composite oxide expressed by the average composition shown in Chemical Formula 1, a lithium composite oxide expressed by the average composition shown in Chemical Formula 2, and the lithium expressed by the average composition shown in Chemical Formula 3 A composite oxide, at least one selected from the group consisting of a lithium composite oxide represented by the average composition shown in Chemical formula 4 and a lithium composite phosphate shown in Chemical formula 5, and the electrolyte solution is vinylene carbonate, LiPF ₆ and LiBF ₄ are included.
(Chemical formula 1)
Li _r Co _(1-s) M3 _s O _{(2-t) Fu}
(Wherein M3 represents at least one selected from the group consisting of nickel, manganese, magnesium, aluminum, boron, titanium, vanadium, chromium, iron, copper, zinc, zirconium, molybdenum, tin, calcium, strontium, and tungsten. R, s, t and u are in the range of 0.8 ≦ r ≦ 1.2, 0 ≦ s <0.5, −0.1 ≦ t ≦ 0.2, 0 ≦ u ≦ 0.1. The value of
(Chemical formula 2)
Li _f Mn _(1-gh) Ni _g M1 _h O _(2-j) F _k
(In the formula, M1 represents at least one selected from the group consisting of cobalt, magnesium, aluminum, boron, titanium, vanadium, chromium, iron, copper, zinc, zirconium, molybdenum, tin, calcium, strontium, and tungsten. f, g, h, j and k are 0.8 ≦ f ≦ 1.2, 0 <g <0.5, 0 ≦ h ≦ 0.5, g + h <1, −0.1 ≦ j ≦ 0. 2. It is a value within the range of 0 ≦ k ≦ 0.1.)
(Chemical formula 3)
Li _m Ni _(1-n) M2 _n O _(2-p) F _q
(Wherein M2 represents at least one selected from the group consisting of cobalt, manganese, magnesium, aluminum, boron, titanium, vanadium, chromium, iron, copper, zinc, zirconium, molybdenum, tin, calcium, strontium, and tungsten. M, n, p and q are 0.8 ≦ m ≦ 1.2, 0.005 ≦ n ≦ 0.5, −0.1 ≦ p ≦ 0.2, 0 ≦ q ≦ 0.1. (The value is within the range.)
(Chemical formula 4)
Li _v Mn _2-w M4 _w O _x F _y
(In the formula, M4 represents at least one selected from the group consisting of cobalt, nickel, magnesium, aluminum, boron, titanium, vanadium, chromium, iron, copper, zinc, molybdenum, tin, calcium, strontium, and tungsten. v, w, x and y are values in the range of 0.9 ≦ v ≦ 1.1, 0 ≦ w ≦ 0.6, 3.7 ≦ x ≦ 4.1, 0 ≦ y ≦ 0.1. is there.)
(Chemical formula 5)
Li _z M5PO ₄
(Wherein M5 represents at least one selected from the group consisting of cobalt, manganese, iron, nickel, magnesium, aluminum, boron, titanium, vanadium, niobium, copper, zinc, molybdenum, calcium, strontium, tungsten and zirconium. Z is a value in the range of 0.9 ≦ z ≦ 1.1.)

According to the first battery of the present invention, since the open circuit voltage at the time of full charge is in the range of 4.25V to 6.00V, a high energy density can be obtained. Moreover, the lithium composite oxide represented by the average composition shown in Chemical Formula 1, the lithium composite oxide represented by the average composition shown in Chemical Formula 2, the lithium composite oxide represented by the average composition shown in Chemical Formula 3 The energy density is further improved because at least one of the group consisting of the lithium composite oxide represented by the average composition shown in Chemical Formula 4 and the lithium composite phosphate shown in Chemical Formula 5 is included. be able to. Furthermore, since the electrolytic solution contains vinylene carbonate, LiPF ₆ and lithium bisoxalate borate, the charge / discharge efficiency can be improved even at high temperatures. Therefore, the energy density can be increased, and excellent charge / discharge efficiency can be obtained even in a high temperature environment.

According to the second battery of the present invention, since the open circuit voltage at the time of full charge is in the range of 4.25V to 6.00V, a high energy density can be obtained. Moreover, the lithium composite oxide represented by the average composition shown in Chemical Formula 1, the lithium composite oxide represented by the average composition shown in Chemical Formula 2, and the lithium composite oxide represented by the average composition shown in Chemical Formula 3 Energy density is improved by including at least one of the oxide, the lithium composite oxide represented by the average composition shown in Chemical Formula 4, and the lithium composite phosphate shown in Chemical Formula 5 In addition, the oxidizing atmosphere in the vicinity of the positive electrode surface can be weakened even in a high temperature environment. Furthermore, since the electrolytic solution contains vinylene carbonate, LiPF ₆ and LiBF ₄ , charge / discharge efficiency can be improved. Therefore, the energy density can be increased, and excellent charge / discharge efficiency can be obtained even in a high temperature environment.

In particular, if the concentration of lithium bisoxalate borate in the electrolytic solution is 0.0005 mol / kg or more and 0.3 mol / kg or less, or the concentration of LiBF _{4 in} the electrolytic solution is 0.0005 mol / kg or more and 0 or less. .. 3 mol / kg or less, or if the content of vinylene carbonate in the electrolyte is in the range of 0.1% by mass or more and 10% by mass or less, the charge / discharge efficiency is further improved. be able to.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows a cross-sectional structure of a secondary battery according to this embodiment. This secondary battery is a so-called lithium ion secondary battery in which lithium (Li) is used as an electrode reactant and the capacity of the negative electrode is represented by a capacity component due to insertion and extraction of lithium. This secondary battery is called a so-called cylindrical type, and is a winding in which a pair of strip-like positive electrode 21 and strip-like negative electrode 22 are wound through a separator 23 inside a substantially hollow cylindrical battery can 11. A rotating electrode body 20 is provided. The battery can 11 is made of, for example, iron plated with nickel, and has one end closed and the other end open. Inside the battery can 11, a pair of insulating plates 12 and 13 are arranged perpendicular to the winding peripheral surface so as to sandwich the winding electrode body 20.

  At the open end of the battery can 11, a battery lid 14, a safety valve mechanism 15 provided inside the battery lid 14 and a heat sensitive resistance element (Positive Temperature Coefficient; PTC element) 16 are interposed via a gasket 17. It is attached by caulking, and the inside of the battery can 11 is sealed. The battery lid 14 is made of, for example, the same material as the battery can 11. The safety valve mechanism 15 is electrically connected to the battery lid 14 via the heat sensitive resistance element 16, and the disk plate 15A is reversed when the internal pressure of the battery exceeds a certain level due to an internal short circuit or external heating. Thus, the electrical connection between the battery lid 14 and the wound electrode body 20 is cut off. When the temperature rises, the heat sensitive resistance element 16 limits the current by increasing the resistance value and prevents abnormal heat generation due to a large current. The gasket 17 is made of, for example, an insulating material, and asphalt is applied to the surface.

  For example, a center pin 24 is inserted in the center of the wound electrode body 20. A positive electrode lead 25 made of aluminum or the like is connected to the positive electrode 21 of the spirally wound electrode body 20, and a negative electrode lead 26 made of nickel or the like is connected to the negative electrode 22. The positive electrode lead 25 is electrically connected to the battery lid 14 by being welded to the safety valve mechanism 15, and the negative electrode lead 26 is welded to and electrically connected to the battery can 11.

  FIG. 2 shows an enlarged part of the spirally wound electrode body 20 shown in FIG. The positive electrode 21 has, for example, a structure in which a positive electrode active material layer 21B is provided on both surfaces of a positive electrode current collector 21A having a pair of opposed surfaces. Although not shown, the positive electrode active material layer 21B may be provided only on one surface of the positive electrode current collector 21A. The positive electrode current collector 21A is made of, for example, a metal foil such as an aluminum foil. The positive electrode active material layer 21B includes, for example, one or more positive electrode materials capable of occluding and releasing lithium as a positive electrode active material, and a conductive material such as graphite and polyfluoride as necessary. Consists of binders such as vinylidene.

Examples of the positive electrode material capable of occluding and releasing lithium include lithium composite oxides having a layered rock salt structure represented by the average composition shown in Chemical Formula 1, Chemical Formula 2 or Chemical Formula 3, and Chemical Formula 4 A lithium composite oxide having a spinel structure represented by an average composition, or a lithium composite phosphate having an olivine structure shown in Chemical formula 5 is preferred. This is because the energy density can be increased. Among these, a lithium composite oxide having a layered rock salt structure represented by the average composition shown in Chemical Formula 1 is more preferable because the energy density can be further increased.
(Chemical formula 1)
Li _r Co _(1-s) M3 _s O _{(2-t) Fu}
(Wherein M3 represents at least one selected from the group consisting of nickel, manganese, magnesium, aluminum, boron, titanium, vanadium, chromium, iron, copper, zinc, zirconium, molybdenum, tin, calcium, strontium, and tungsten. R, s, t and u are in the range of 0.8 ≦ r ≦ 1.2, 0 ≦ s <0.5, −0.1 ≦ t ≦ 0.2, 0 ≦ u ≦ 0.1. (Note that the composition of lithium varies depending on the state of charge and discharge, and the value of r represents a value in a fully discharged state.)
(Chemical formula 2)
Li _f Mn _(1-gh) Ni _g M1 _h O _(2-j) F _k
(In the formula, M1 represents at least one selected from the group consisting of cobalt, magnesium, aluminum, boron, titanium, vanadium, chromium, iron, copper, zinc, zirconium, molybdenum, tin, calcium, strontium, and tungsten. f, g, h, j and k are 0.8 ≦ f ≦ 1.2, 0 <g <0.5, 0 ≦ h ≦ 0.5, g + h <1, −0.1 ≦ j ≦ 0. 2. The value is in the range of 0 ≦ k ≦ 0.1, where the composition of lithium varies depending on the state of charge and discharge, and the value of f represents the value in the fully discharged state.
(Chemical formula 3)
Li _m Ni _(1-n) M2 _n O _(2-p) F _q
(Wherein M2 represents at least one selected from the group consisting of cobalt, manganese, magnesium, aluminum, boron, titanium, vanadium, chromium, iron, copper, zinc, zirconium, molybdenum, tin, calcium, strontium, and tungsten. M, n, p and q are 0.8 ≦ m ≦ 1.2, 0.005 ≦ n ≦ 0.5, −0.1 ≦ p ≦ 0.2, 0 ≦ q ≦ 0.1. (Note that the lithium composition varies depending on the state of charge and discharge, and the value of m represents a value in a fully discharged state.)
(Chemical formula 4)
Li _v Mn _2-w M4 _w O _x F _y
(In the formula, M4 represents at least one selected from the group consisting of cobalt, nickel, magnesium, aluminum, boron, titanium, vanadium, chromium, iron, copper, zinc, molybdenum, tin, calcium, strontium, and tungsten. v, w, x and y are values in the range of 0.9 ≦ v ≦ 1.1, 0 ≦ w ≦ 0.6, 3.7 ≦ x ≦ 4.1, 0 ≦ y ≦ 0.1. (Note that the composition of lithium varies depending on the state of charge and discharge, and the value of v represents the value in a fully discharged state.)
(Chemical formula 5)
Li _z M5PO ₄
(Wherein M5 represents at least one selected from the group consisting of cobalt, manganese, iron, nickel, magnesium, aluminum, boron, titanium, vanadium, niobium, copper, zinc, molybdenum, calcium, strontium, tungsten and zirconium. Z is a value in the range of 0.9 ≦ z ≦ 1.1, wherein the composition of lithium varies depending on the state of charge and discharge, and the value of z represents the value in the fully discharged state.

In particular, a lithium composite oxide having a layered rock salt type structure represented by the average composition shown in Chemical Formula 1 and a lithium composite oxide having a layered rock salt type structure represented by the average composition shown in Chemical Formula 2 or Chemical Formula 3 At least one selected from the group consisting of a lithium composite oxide having a spinel structure represented by the average composition shown in Chemical Formula 4 and a lithium composite phosphate having an olivine structure shown in Chemical Formula 5 And are preferably used in combination. Only the lithium composite oxide having a layered rock salt structure represented by the average composition shown in Chemical Formula 1 has a strong oxidizing atmosphere near the positive electrode surface, particularly at high temperatures. This is because the atmosphere can be weakened. Specific examples of such a lithium composite oxide or lithium composite phosphate include Li _a CoO ₂ (a≈1), Li _c1 Ni _c2 Co _1-c2 O ₂ (c1≈1,0, <c2 ≦ 0.5), LiNi _0.50 Co _0.20 Mn _0.30 O ₂ , Li _b NiO ₂ (b≈1), Li _c3 Ni _c4 Co _1-c4 O ₂ (c3≈1, 0.5 <c4 <1), Li _d Mn ₂ O ₄ (d≈1) or Li _e FePO ₄ (e≈1).

  In addition to these positive electrode materials, other positive electrode materials may be mixed and used as the positive electrode material capable of inserting and extracting lithium. Examples of other positive electrode materials include other lithium oxides, lithium sulfides, and interlayer compounds containing other lithium.

  The negative electrode 22 has, for example, a structure in which a negative electrode active material layer 22B is provided on both surfaces of a negative electrode current collector 22A having a pair of opposed surfaces. Although not shown, the negative electrode active material layer 22B may be provided only on one surface of the negative electrode current collector 22A. The anode current collector 22A is made of, for example, a metal foil such as a copper foil.

  The negative electrode active material layer 22B includes one or more negative electrode materials capable of inserting and extracting lithium as the negative electrode active material, and the positive electrode active material layer 21B as necessary. It is comprised including the same binding material.

  In this secondary battery, the charge capacity of the negative electrode material capable of inserting and extracting lithium is larger than the charge capacity of the positive electrode 21 so that lithium metal does not deposit on the negative electrode 22 during the charge. It has become.

  Examples of the negative electrode material capable of inserting and extracting lithium include non-graphitizable carbon, graphitizable carbon, graphite, pyrolytic carbons, cokes, glassy carbons, and fired organic polymer compounds , Carbon materials such as carbon fiber or activated carbon. Among these, examples of coke include pitch coke, needle coke, and petroleum coke. An organic polymer compound fired body is a carbonized material obtained by firing a polymer material such as a phenol resin or a furan resin at an appropriate temperature, and part of it is non-graphitizable carbon or graphitizable carbon. Some are classified as: These carbon materials are preferable because the change in crystal structure that occurs during charge and discharge is very small, a high charge and discharge capacity can be obtained, and good cycle characteristics can be obtained. In particular, graphite is preferable because it has a high electrochemical equivalent and can provide a high energy density. Further, non-graphitizable carbon is preferable because excellent cycle characteristics can be obtained. Furthermore, those having a low charge / discharge potential, specifically, those having a charge / discharge potential close to that of lithium metal are preferable because a high energy density of the battery can be easily realized.

  Examples of the negative electrode material capable of inserting and extracting lithium include materials capable of inserting and extracting lithium and containing at least one of a metal element and a metalloid element as a constituent element. . This is because a high energy density can be obtained by using such a material. In particular, the use with a carbon material is more preferable because a high energy density can be obtained and excellent cycle characteristics can be obtained. The negative electrode material may be a single element, alloy or compound of a metal element or metalloid element, or may have at least a part of one or more of these phases. In the present invention, alloys include those containing one or more metal elements and one or more metalloid elements in addition to those composed of two or more metal elements. Moreover, the nonmetallic element may be included. There are structures in which a solid solution, a eutectic (eutectic mixture), an intermetallic compound, or two or more of them coexist.

  Examples of the metal element or metalloid element constituting the negative electrode material include magnesium, boron, aluminum, gallium (Ga), indium (In), silicon (Si), germanium (Ge), tin, lead (Pb), Bismuth (Bi), cadmium (Cd), silver (Ag), zinc, hafnium (Hf), zirconium, yttrium (Y), palladium (Pd), or platinum (Pt) can be used. These may be crystalline or amorphous.

  Among these, as the negative electrode material, a material containing a 4B group metal element or a semimetal element in the short-period type periodic table as a constituent element is preferable, and at least one of silicon and tin is particularly preferable as a constituent element. This is because silicon and tin have a large ability to occlude and release lithium, and a high energy density can be obtained.

  Examples of the tin alloy include, as the second constituent element other than tin, silicon, nickel, copper, iron, cobalt, manganese, zinc, indium, silver, titanium, germanium, bismuth, antimony (Sb), and chromium. The thing containing at least 1 sort (s) of the group which consists of is mentioned. As an alloy of silicon, for example, as a second constituent element other than silicon, among the group consisting of tin, nickel, copper, iron, cobalt, manganese, zinc, indium, silver, titanium, germanium, bismuth, antimony and chromium The thing containing at least 1 sort (s) of these is mentioned.

  Examples of the tin compound or silicon compound include those containing oxygen (O) or carbon (C), and may contain the second constituent element described above in addition to tin or silicon.

Examples of the negative electrode material capable of inserting and extracting lithium further include other metal compounds or polymer materials. Examples of other metal compounds include oxides such as MnO ₂ , V ₂ O ₅ , and V ₆ O ₁₃ , sulfides such as NiS and MoS, and lithium nitrides such as LiN ₃ , and polymer materials include polyacetylene. Or a polypyrrole etc. are mentioned.

  The separator 23 is made of, for example, a porous film made of synthetic resin such as polytetrafluoroethylene, polypropylene, or polyethylene, or a porous film made of ceramic, and has a structure in which two or more kinds of porous films are laminated. May be. Among these, a porous film made of polyolefin is preferable because it is excellent in short-circuit preventing effect and can improve the safety of the battery due to the shutdown effect.

  The separator 23 is impregnated with an electrolytic solution that is a liquid electrolyte. This electrolytic solution contains a solvent and an electrolyte salt dissolved in the solvent.

The electrolyte salt contains LiPF ₆ and at least one of LiBF ₄ and lithium bisoxalate borate shown in Chemical formula 6. This is because the ion conductivity of the electrolyte can be increased by using LiPF ₆ . On the other hand, only with the LiPF _6, since the battery capacity is reduced, by mixing LiBF _4, it is possible to suppress the decomposition of LiPF _6. In addition, by mixing lithium bisoxalate borate with LiPF ₆ , the current distribution of the electrolyte solution in the positive electrode 21 can be made uniform even in a high temperature environment.

The concentration of LiPF ₆ is preferably in the range of 0.1 mol / kg or more and 2.0 mol / kg or less in the electrolytic solution. This is because the ion conductivity can be further increased within this range.

The concentration of LiBF ₄ is preferably in the range of 0.0005 mol / kg to 0.3 mol / kg in the electrolytic solution. If the amount is small, the effect of mixing is not sufficient, and if the amount is large, the charge / discharge efficiency is lowered. Moreover, it is preferable that the density | concentration of lithium bis oxalate borate exists in the range of 0.0005 mol / kg or more and 0.3 mol / kg or less in electrolyte solution. If the amount is small, the effect of mixing is not sufficient, and if the amount is large, the charge / discharge efficiency is lowered. Furthermore, when LiBF ₄ and lithium bisoxalate borate are used in combination, the total of these concentrations in the electrolytic solution is preferably in the range of 0.0005 mol / kg to 0.3 mol / kg. . If the amount is small, the effect of mixing them is not sufficient, and if the amount is large, the charge / discharge efficiency is lowered.

As the electrolyte salt, in addition to these electrolyte salts, other electrolyte salts may be mixed and used. Examples of other electrolyte salts include LiAsF ₆ , LiClO ₄ , LiB (C ₆ H ₅ ) ₄ , LiCH ₃ SO ₃ , LiCF ₃ SO ₃ , LiN (SO ₂ CF ₃ ) ₂ , and LiC (SO ₂ CF ₃ ). ₃ , LiAlCl ₄ , LiSiF ₆ , LiCl, difluoro [oxolato-O, O ′] lithium borate shown in Chemical Formula 7, LiBr, or the like. Any one of the other electrolyte salts may be used alone, or a plurality of them may be used in combination.

  As the solvent, for example, cyclic carbonate such as ethylene carbonate or propylene carbonate can be used, and it is preferable to use one of ethylene carbonate and propylene carbonate, in particular, a mixture of both. This is because the cycle characteristics can be improved.

  As the solvent, in addition to these cyclic carbonates, it is preferable to use a mixture of chain carbonates such as diethyl carbonate, dimethyl carbonate, ethylmethyl carbonate or methylpropyl carbonate. This is because high ionic conductivity can be obtained.

  The solvent preferably further contains 4-fluoro-1,3-dioxolan-2-one. This is because the cycle characteristics can be further improved.

  In addition to these, examples of the solvent include butylene carbonate, γ-butyrolactone, γ-valerolactone, 1,2-dimethoxyethane, tetrahydrofuran, 2-methyltetrahydrofuran, 1,3-dioxolane, 4-methyl-1,3- Dioxolane, methyl acetate, methyl propionate, acetonitrile, glutaronitrile, adiponitrile, methoxyacetonitrile, 3-methoxypropionitrile, N, N-dimethylformamide, N-methylpyrrolidinone, N-methyloxazolidinone, N, N-dimethyl Examples include imidazolidinone, nitromethane, nitroethane, sulfolane, dimethyl sulfoxide, and trimethyl phosphate.

  A compound obtained by substituting at least a part of hydrogen in these non-aqueous solvents with fluorine may be preferable because the reversibility of the electrode reaction may be improved depending on the type of electrode to be combined. Moreover, any 1 type may be used independently for a solvent, and multiple types may be mixed and used for it.

The solvent contains vinylene carbonate. This is because a film can be formed on the negative electrode 22 to suppress the decomposition reaction of LiBF ₄ . Moreover, it is because the current density of the electrolyte solution in the negative electrode 22 can be made uniform, and charge / discharge efficiency can be improved.

The content of vinylene carbonate is preferably in the range of 0.1% by mass to 10% by mass in the electrolytic solution. This is because if it is less, the effect of suppressing the decomposition reaction of LiBF ₄ or the effect of making the current density of the electrolyte in the negative electrode 22 uniform is not sufficient, and if it is more, the charge / discharge efficiency is lowered.

  This secondary battery is designed so that the open circuit voltage (that is, the battery voltage) at the time of full charge is in the range of 4.25V to 6.00V. Therefore, even if the positive electrode active material is the same as that of the battery having an open circuit voltage of 4.20 V at the time of full charge, the amount of lithium released per unit mass is increased. Accordingly, the positive electrode active material and the negative electrode active material And the amount has been adjusted. As a result, a high energy density can be obtained. Moreover, when the open circuit voltage at the time of complete charge is in the range of 4.25 V to 4.60 V, the effect of using the above-described positive electrode material, electrolyte salt, and vinylene carbonate can be enhanced.

  For example, the secondary battery can be manufactured as follows.

  First, for example, a positive electrode mixture is prepared by mixing the above-described positive electrode active material, a conductive material, and a binder, and this positive electrode mixture is dispersed in a solvent such as N-methyl-2-pyrrolidone to obtain a paste. A positive electrode mixture slurry is prepared. Next, the positive electrode mixture slurry is applied to the positive electrode current collector 21 </ b> A, the solvent is dried, and the positive electrode active material layer 21 </ b> B is formed by compression molding using a roll press or the like, thereby forming the positive electrode 21.

  Further, for example, a negative electrode active material and a binder are mixed to prepare a negative electrode mixture, and the negative electrode mixture is dispersed in a solvent such as N-methyl-2-pyrrolidone to obtain a paste-like negative electrode mixture slurry. Is made. Next, the negative electrode mixture slurry is applied to the negative electrode current collector 22A, the solvent is dried, and the negative electrode active material layer 22B is formed by compression molding with a roll press machine or the like, and the negative electrode 22 is manufactured.

  Subsequently, the positive electrode lead 25 is attached to the positive electrode current collector 21A by welding or the like, and the negative electrode lead 26 is attached to the negative electrode current collector 22A by welding or the like. After that, the positive electrode 21 and the negative electrode 22 are wound through the separator 23, and the tip of the positive electrode lead 25 is welded to the safety valve mechanism 15, and the tip of the negative electrode lead 26 is welded to the battery can 11. The positive electrode 21 and the negative electrode 22 are sandwiched between a pair of insulating plates 12 and 13 and stored in the battery can 11. After the positive electrode 21 and the negative electrode 22 are accommodated in the battery can 11, the electrolytic solution is injected into the battery can 11 and impregnated in the separator 23. After that, the battery lid 14, the safety valve mechanism 15, and the heat sensitive resistance element 16 are fixed to the opening end of the battery can 11 by caulking through a gasket 17. Thereby, the secondary battery shown in FIG. 1 is formed.

In the secondary battery, when charged, for example, lithium ions are released from the positive electrode active material layer 21B and inserted into the negative electrode active material layer 22B through the electrolytic solution. In addition, when discharging is performed, for example, lithium ions are released from the negative electrode active material layer 22B and inserted into the positive electrode active material layer 21B through the electrolytic solution. At that time, the positive electrode 21 is represented by the lithium composite oxide represented by the average composition shown in Chemical formula 1, the lithium composite oxide represented by the average composition shown in Chemical formula 2, and the average composition shown in Chemical formula 3. Since the lithium composite oxide, the lithium composite oxide represented by the average composition shown in Chemical Formula 4 or the lithium composite phosphate shown in Chemical Formula 5 is contained, the energy density is improved. Further, since the electrolytic solution contains vinylene carbonate, LiPF ₆ and lithium bisoxalate borate, the ionic conductivity of the electrolytic solution is improved even in a high temperature environment, and the electrolytic solution in the electrode The current density becomes uniform.

The positive electrode 21 is represented by the lithium composite oxide represented by the average composition shown in Chemical Formula 1, the lithium composite oxide represented by the average composition shown in Chemical Formula 2, and the average composition shown in Chemical Formula 3. And at least one of the group consisting of the lithium composite oxide represented by the average composition shown in Chemical formula 4 and the lithium composite phosphate shown in Chemical formula 5 As the density improves, the oxidizing atmosphere in the vicinity of the positive electrode surface weakens. Further, the electrolyte solution, vinylene carbonate, and LiPF _6, because it contains and LiBF _4, charge and discharge efficiency is improved.

As described above, in one embodiment of the present embodiment, since the open circuit voltage at the time of full charge is in the range of 4.25V to 6.00V, high energy density can be obtained. Further, a lithium composite oxide represented by the average composition shown in Chemical Formula 1, a lithium composite oxide represented by the average composition shown in Chemical Formula 2, a lithium composite oxide represented by the average composition shown in Chemical Formula 3, Since at least one of the group consisting of the lithium composite oxide represented by the average composition shown in Chemical formula 4 and the lithium composite phosphate shown in Chemical formula 5 is included, the energy density can be further improved. it can. Furthermore, since the electrolytic solution contains vinylene carbonate, LiPF ₆ and lithium bisoxalate borate, the charge / discharge efficiency can be improved even at high temperatures. Therefore, the energy density can be increased, and excellent charge / discharge efficiency can be obtained even in a high temperature environment.

Further, in another aspect of the present embodiment, since the open circuit voltage at the time of full charge is in the range of 4.25V to 6.00V, a high energy density can be obtained. Further, when the positive electrode 21 includes a lithium composite oxide represented by the average composition shown in Chemical Formula 1, the lithium composite oxide represented by the average composition shown in Chemical Formula 2 and the average composition shown in Chemical Formula 3 And at least one of the group consisting of the lithium composite oxide represented by the average composition shown in Chemical formula 4 and the lithium composite phosphate shown in Chemical formula 5 In addition to improving the energy density, the oxidizing atmosphere in the vicinity of the positive electrode surface can be weakened even in a high temperature environment. Furthermore, since the electrolytic solution contains vinylene carbonate, LiPF ₆ and LiBF ₄ , charge / discharge efficiency can be improved. Therefore, the energy density can be increased, and excellent charge / discharge efficiency can be obtained even in a high temperature environment.

In particular, if the concentration of lithium bisoxalate borate in the electrolytic solution is 0.0005 mol / kg or more and 0.3 mol / kg or less, or the concentration of LiBF _{4 in} the electrolytic solution is 0.0005 mol / kg or more and 0 or less. .. 3 mol / kg or less, or if the content of vinylene carbonate in the electrolyte is in the range of 0.1% by mass or more and 10% by mass or less, the charge / discharge efficiency is further improved. be able to.

  Furthermore, specific examples of the present invention will be described in detail.

(Examples 1-1 to 1-7)
The secondary battery shown in FIG. 1 was produced. First, as the positive electrode active material, the lithium composite oxide represented by the average composition shown in Chemical Formula 1 and the lithium composite oxide having the average composition shown in Chemical Formula 3 are represented by the average composition shown in Chemical Formula 1. Lithium composite oxide: Lithium composite oxide having an average composition shown in Chemical formula 3 = 80: 20 After mixing, 94% by mass of this positive electrode active material mixture and ketjen black (amorphous) as the conductive material Active carbon powder) 3% by mass and 3% by mass of polyvinylidene fluoride as a binder were mixed and dispersed in N-methyl-2-pyrrolidone as a solvent to obtain a positive electrode mixture slurry. The lithium composite oxide represented by the average composition shown in Chemical Formula ₁ was LiCoO _2, and the lithium composite oxide having the average composition shown in Chemical Formula 3 was LiNi _0.5 Co _0.2 Mn _0.3 O ₂ . Next, the positive electrode mixture slurry was uniformly applied to both surfaces of a positive electrode current collector 21A made of a strip-shaped aluminum foil having a thickness of 20 μm, dried, and compression-molded to form a positive electrode active material layer 21B to produce a positive electrode 21. . After that, an aluminum positive electrode lead 25 was attached to one end of the positive electrode current collector 21A.

  Further, 90% by mass of granular graphite powder having an average particle size of 30 μm as a negative electrode active material and 10% by mass of polyvinylidene fluoride as a binder are mixed and dispersed in N-methyl-2-pyrrolidone as a solvent to mix the negative electrode. An agent slurry was obtained. Next, this negative electrode mixture slurry was uniformly applied to both surfaces of a negative electrode current collector 22A made of a strip-shaped copper foil having a thickness of 15 μm, dried, and compression-molded to form a negative electrode active material layer 22B, thereby producing a negative electrode 22. At that time, the amount of the positive electrode active material and the amount of the negative electrode active material were adjusted so that the open circuit voltage (that is, the battery voltage) at the time of full charge was 4.25 V in Example 1-1. 2 to 4.30V, Example 1-3 to 4.35V, Example 1-4 to 4.40V, and Example 1-5 to 4.45V. Furthermore, it was designed to be 4.50 V in Example 1-6 and 4.60 V in Example 1-7. Subsequently, a negative electrode lead 26 made of nickel was attached to one end of the negative electrode current collector 22A.

  After preparing the positive electrode 21 and the negative electrode 22, a separator 23 made of a microporous film is prepared, and the negative electrode 22, the separator 23, the positive electrode 21, and the separator 23 are laminated in this order, and this laminate is wound many times in a spiral shape. Thus, a jelly roll-type wound electrode body 20 having an outer diameter of 17.8 mm was produced.

After producing the wound electrode body 20, the wound electrode body 20 is sandwiched between the pair of insulating plates 12 and 13, the negative electrode lead 26 is welded to the battery can 11, and the positive electrode lead 25 is welded to the safety valve mechanism 15. The wound electrode body 20 was housed inside a nickel-plated iron battery can 11. Subsequently, an electrolytic solution was injected into the battery can 11 by a reduced pressure method. In the electrolyte solution, vinylene carbonate is added to a mixed solvent in which ethylene carbonate and dimethyl carbonate are mixed at a mass ratio of ethylene carbonate: dimethyl carbonate = 3: 7, and LiPF ₆ and LiBF ₄ are dissolved as electrolyte salts. Was used. The content of vinylene carbonate in the electrolytic solution was 1% by mass, and the concentrations of LiPF ₆ and LiBF ₄ were 0.99 mol / kg and 0.01 mol / kg, respectively.

  Thereafter, the battery lid 14 was caulked to the battery can 11 via the gasket 17 to produce a cylindrical secondary battery having a diameter of 18 mm and a height of 65 mm.

Comparative Examples 1-1-1 to 1-2-1 for Examples 1-1 to 1-7, 1-1-1, 1-4-1, 1-5-1, 1-6-1, 1- As 7-1, a secondary battery was fabricated in the same manner as in Examples 1-1 to 1-7 except that LiBF ₄ was not used. At that time, the concentration of LiPF _{6 in} the electrolytic solution was 1.00 mol / l. Further, as Comparative Examples 1-1-2, 1-2-2, 1-3-2, 1-4-2, 1-5-2, 1-6-2, and 1-7-2, LiNi _0.5 Co _A secondary battery was fabricated in the same manner as in Examples 1-1 to 1-7, except that _0.2 Mn _0.3 O ₂ was not used. Furthermore, vinylene carbonate was used as Comparative Example 1-1-3, 1-2-3, 1-3-3, 1-4-4, 1-5-3, 1-6-3, 1-7-1. A secondary battery was fabricated in the same manner as in Examples 1-1 to 1-7, except that it was not used.

Furthermore, as Comparative Examples 1-8-1 to 1-8-4, the amount of the positive electrode active material and the amount of the negative electrode active material are adjusted so that the open circuit voltage at the time of full charge is 4.20V. Except for this, secondary batteries were fabricated in the same manner as in Examples 1-1 to 1-7. At that time, in Comparative Example 1-8-2, LiBF ₄ was not used, and the concentration of LiPF _{6 in} the electrolytic solution was set to 1.00 mol / l. In Comparative Example 1-8-3, LiNi _0.5 Co _0.2 Mn _0.3 O ₂ was not used. In Comparative Example 1-8-4, vinylene carbonate was not used.

  The fabricated secondary batteries of Examples 1-1 to 1-7 and Comparative examples 1-1-1 to 1-8-4 were charged and discharged, and the high-temperature cycle characteristics were examined. Charging is performed in a high-temperature bath set at 45 ° C. with a constant current of 500 mA until the upper limit voltage is reached, then with the constant voltage remaining at the upper limit voltage until the total charging time reaches 5 hours. Was performed at a constant current of 300 mA until the battery voltage reached 3.00V. The high-temperature cycle characteristics are obtained by repeating this charge / discharge, from the discharge capacity maintenance rate at the 100th cycle to the discharge capacity at the second cycle, that is, (discharge capacity at the 100th cycle / discharge capacity at the second cycle) × 100 (%). Asked. Further, the charging upper limit voltage was as shown in Tables 1, 2 and 3. The results are shown in Table 1, Table 2 and Table 3.

As can be seen from Tables 1, 2 and 3, as the positive electrode active material, a lithium composite oxide represented by the average composition shown in Chemical Formula 1 and a lithium composite oxide represented by the average composition shown in Chemical Formula 3 According to Examples 1-1 to 1-7 in which vinylene carbonate, LiPF ₆ and LiBF ₄ were included in the electrolytic solution, Comparative Examples 1-1-1 and 1-2 without using LiBF ₄ were used. -1,1-3-1, 1-4-1, 1-5-1, 1-6-1, 1-7-1, or lithium composite oxidation represented by the average composition shown in Chemical formula 3 More than Comparative Example 1-1-2, 1-2-2, 1-3-2, 1-4-2, 1-5-2, 1-6-2, and 1-7-2 using no product Or Comparative Example 1-1-3 without using vinylene carbonate 1-1-3, 1-2-3, 1-3-3, 1-4-4, 1-5-3, 1-6-3, 1-7- 3 Also, high-temperature cycle characteristics, respectively was significantly improved. In Comparative Examples 1-8-1 to 1-8-4 in which the charging upper limit voltage was 4.20 V, the lithium composite oxide represented by the average composition shown in Chemical Formula 1 and the average composition shown in Chemical Formula 3 In addition, the effects of using vinylene carbonate, LiPF ₆ and LiBF ₄ were hardly observed.

That is, in a battery having an open circuit voltage in the range of 4.25 V or more and 6.00 V or less when fully charged, the lithium composite oxide represented by the average composition shown in Chemical Formula 1 and The cycle characteristics can be improved even in a high-temperature environment by including a lithium composite oxide represented by an average composition and including vinylene carbonate, LiPF ₆ and LiBF _{4 in the} electrolyte. I understood.

(Examples 2-1 to 2-5)
Instead of LiNi _0.5 Co _0.2 Mn _0.3 O ₂ , LiNi _0.33 Co _0.33 Mn _0.33 O ₂ , LiNi _0.5 Co _0.2 Mn _0.3 O ₂ F _0.01 , LiNi _0.5 Mn _0.5 O ₂ , LiMn ₂ O ₄ , or LiFePO ₄ was used. Except for the above, a secondary battery was fabricated in the same manner as in Example 1-3. Note that LiNi _0.33 Co _0.33 Mn _0.33 O ₂ is a lithium composite oxide represented by the average composition shown in Chemical _{Formula 2} , and LiNi _0.5 Co _0.2 Mn _0.3 O ₂ F _0.01 and LiNi _0.5 Mn _0.5 O ₂ are LiMn ₂ O ₄ is a lithium composite oxide represented by the average composition shown in Chemical formula ₄ , and LiFePO ₄ is the lithium composite phosphoric acid shown in Chemical formula 5. Salt.

  About the produced secondary battery of Examples 2-1 to 2-5, it carried out similarly to Example 1-3, and investigated high temperature cycling characteristics. The results are shown in Table 4.

As can be seen from Table 4, as in Example 1-3, LiNi _0.33 Co _0.33 Mn _0.33 O ₂ , LiNi _0.5 Co _0.2 Mn _0.3 O ₂ F _0.01 , LiNi _0.5 Mn _0.5 O ₂ , LiMn ₂ O ₄ , or LiFePO _{4 In} Examples 2-1 to 2-5 using ₄ as well, high values were obtained for the high-temperature cycle characteristics.

  That is, in addition to the lithium composite oxide represented by the average composition shown in Chemical formula 1, the lithium composite oxide represented by the average composition shown in Chemical formula 2 and the average composition shown in the other chemical formula 3 Even if lithium composite oxide, lithium composite oxide represented by the average composition shown in chemical formula 4 or lithium composite phosphate shown in chemical formula 5 is used in combination, cycle characteristics in a high temperature environment can be improved. I found out that

(Examples 3-1 to 3-5)
A secondary battery was fabricated in the same manner as in Example 1-3, except that the mixing ratio of LiCoO ₂ and LiNi _0.5 Co _0.2 Mn _0.3 O ₂ was changed. And LiCoO _2, proportions by weight ratio of the _{LiNi 0.5 Co 0.2 Mn 0.3 O 2} (LiCoO 2: LiNi 0.5 Co 0.2 Mn 0.3 O 2) is to 20:80 in Example 3-1, Example 3-2 50:50, 70:30 in Example 3-3, 90:10 in Example 3-4, and 95: 5 in Example 3-5.

  For the fabricated secondary batteries of Examples 3-1 to 3-5, high temperature cycle characteristics were examined in the same manner as in Example 1-3. The results are shown in Table 5.

As can be seen from Table 5, also in Examples 3-1 to 3-5 in which the mixing ratio of LiCoO ₂ and LiNi _0.5 Co _0.2 Mn _0.3 O ₂ was changed, as in Example 1-3, A high value was obtained.

  That is, the lithium composite oxide represented by the average composition shown in Chemical Formula 1, the lithium composite oxide represented by the average composition shown in Chemical Formula 2, and the lithium composite oxide represented by the average composition shown in Chemical Formula 3 , Even if the mixing ratio of at least one selected from the group consisting of the lithium composite oxide represented by the average composition shown in Chemical formula 4 and the lithium composite phosphate shown in Chemical formula 5 is changed, It was found that the characteristics can be improved.

(Examples 4-1 to 4-6)
A secondary battery was fabricated in the same manner as in Example 1-3, except that the concentration of LiBF _{4 in} the electrolytic solution was changed. At that time, the concentration of LiBF _{4 in} the electrolytic solution was 0.5 mol / kg in Example 4-1, 0.3 mol / kg in Example 4-2, and 0.1 mol / kg in Example 4-3. In Example 4-4, the concentration was 0.05 mol / kg, in Example 4-5, 0.001 mol / kg, and in Example 4-6, 0.0005 mol / kg. The total concentration of the electrolyte salt in the electrolytic solution was 1.00 mol / l.

  For the fabricated secondary batteries of Examples 4-1 to 4-6, high temperature cycle characteristics were examined in the same manner as in Example 1-3. The results are shown in Table 6.

As can be seen from Table 6, the high-temperature cycle characteristics increased as the concentration of LiBF _{4 in} the electrolytic solution increased, and a tendency to decrease after showing the maximum value was observed.

That is, it has been found that it is preferable that the concentration of LiBF _{4 in} the electrolytic solution is 0.0005 mol / kg or more and 0.3 mol / kg or less.

(Examples 5-1 to 5-4)
A secondary battery was fabricated in the same manner as in Example 1-3, except that the content of vinylene carbonate in the electrolytic solution was 10% by mass, 5% by mass, 2% by mass, or 0.1% by mass. .

  For the fabricated secondary batteries of Examples 5-1 to 5-4, high temperature cycle characteristics were examined in the same manner as in Example 1-3. The results are shown in Table 7.

  As can be seen from Table 7, the high-temperature cycle characteristics increased as the content of vinylene carbonate in the electrolytic solution increased, and a tendency to decrease after showing the maximum value was observed.

  That is, it has been found that it is preferable if the content of vinylene carbonate in the electrolytic solution is 0.1 mass% or more and 10 mass% or less.

(Examples 6-1 to 6-6)
A secondary battery was fabricated in the same manner as in Example 1-3, except that lithium bisoxalate borate (LiBOB) was mixed and used as the electrolyte salt in addition to LiPF ₆ and LiBF ₄ . At that time, the concentrations of LiPF ₆ , LiBF ₄ and lithium bisoxalate borate in the electrolyte were 0.99 mol / kg, 0.0075 mol / kg and 0.0025 mol / kg in Example 6-1, respectively. In 6-2, they are 0.99 mol / kg, 0.005 mol / kg, and 0.005 mol / kg, respectively, and in Example 6-3, they are 0.99 mol / kg, 0.0025 mol / kg, and 0.0075 mol / kg, respectively. In Example 6-4, 0.9 mol / kg, 0.075 mol / kg, and 0.025 mol / kg, respectively, and in Example 6-5, 0.9 mol / kg, 0.05 mol / kg, and 0, respectively. 0.05 mol / kg, and in Example 6-6, 0.9 mol / kg, 0.025 mol / kg,. It was 75mol / kg.

  For the fabricated secondary batteries of Examples 6-1 to 6-6, the high temperature cycle characteristics were examined in the same manner as in Example 1-3. The results are shown in Table 8.

As can be seen from Table 8, as in Examples 1-3 and 4-3, Examples 6-1 to 6-6 were prepared by mixing LiBF ₄ and lithium bisoxalate borate and changing their contents. Also, a high value was obtained for the high-temperature cycle characteristics.

That is, it has been found that even when LiBF ₄ and lithium bisoxalate borate are mixed and used, the cycle characteristics under a high temperature environment can be improved.

(Examples 7-1 to 7-7)
The secondary battery shown in FIG. 1 was produced. First, as the positive electrode active material, the lithium composite oxide represented by the average composition shown in Chemical Formula 1 and the lithium composite oxide having the average composition shown in Chemical Formula 3 are represented by the average composition shown in Chemical Formula 1. Lithium composite oxide: Lithium composite oxide having an average composition shown in Chemical formula 3 = 80: 20 After mixing, 94% by mass of this positive electrode active material mixture and ketjen black (amorphous) as the conductive material Active carbon powder) 3% by mass and 3% by mass of polyvinylidene fluoride as a binder were mixed and dispersed in N-methyl-2-pyrrolidone as a solvent to obtain a positive electrode mixture slurry. The lithium composite oxide represented by the average composition shown in Chemical Formula ₁ was LiCoO _2, and the lithium composite oxide having the average composition shown in Chemical Formula 3 was LiNi _0.5 Co _0.2 Mn _0.3 O ₂ . Next, the positive electrode mixture slurry was uniformly applied to both surfaces of a positive electrode current collector 21A made of a strip-shaped aluminum foil having a thickness of 20 μm, dried, and compression-molded to form a positive electrode active material layer 21B to produce a positive electrode 21. . After that, an aluminum positive electrode lead 25 was attached to one end of the positive electrode current collector 21A.

  Further, 90% by mass of granular graphite powder having an average particle size of 30 μm as a negative electrode active material and 10% by mass of polyvinylidene fluoride as a binder are mixed and dispersed in N-methyl-2-pyrrolidone as a solvent to mix the negative electrode. An agent slurry was obtained. Next, this negative electrode mixture slurry was uniformly applied to both surfaces of a negative electrode current collector 22A made of a strip-shaped copper foil having a thickness of 15 μm, dried, and compression-molded to form a negative electrode active material layer 22B, thereby producing a negative electrode 22. At that time, the amount of the positive electrode active material and the amount of the negative electrode active material were adjusted so that the open circuit voltage (that is, the battery voltage) at the time of full charge was 4.25 V in Example 7-1. As in Example 7-3, it becomes 4.35V, in Example 7-3, it becomes 4.40V, so that it becomes 4.40V in Example 7-3, and it becomes 4.45V in Example 7-5. Furthermore, it was designed to be 4.50 V in Example 7-6 and 4.60 V in Example 7-7. Subsequently, a negative electrode lead 26 made of nickel was attached to one end of the negative electrode current collector 22A.

  After preparing the positive electrode 21 and the negative electrode 22, a separator 23 made of a microporous film is prepared, and the negative electrode 22, the separator 23, the positive electrode 21, and the separator 23 are laminated in this order, and this laminate is wound many times in a spiral shape. Thus, a jelly roll-type wound electrode body 20 having an outer diameter of 17.8 mm was produced.

After producing the wound electrode body 20, the wound electrode body 20 is sandwiched between the pair of insulating plates 12 and 13, the negative electrode lead 26 is welded to the battery can 11, and the positive electrode lead 25 is welded to the safety valve mechanism 15. The wound electrode body 20 was housed inside a nickel-plated iron battery can 11. Subsequently, an electrolytic solution was injected into the battery can 11 by a reduced pressure method. In the electrolyte, vinylene carbonate is added to a mixed solvent in which ethylene carbonate and dimethyl carbonate are mixed at a mass ratio of ethylene carbonate: dimethyl carbonate = 3: 7, and LiPF ₆ and lithium bisoxalate borate ( What dissolved LiBOB) was used. The content of vinylene carbonate in the electrolytic solution was 1% by mass, and the concentrations of LiPF ₆ and lithium bisoxalate borate were 0.99 mol / kg and 0.01 mol / kg, respectively.

  Thereafter, the battery lid 14 was caulked to the battery can 11 via the gasket 17 to produce a cylindrical secondary battery having a diameter of 18 mm and a height of 65 mm.

Comparative Examples 7-1-1, 7-2-1, 7-3-1, 7-4-1, 7-5-1, 7-6-1, 7- to Examples 7-1 to 7-7 A secondary battery was fabricated in the same manner as in Examples 7-1 to 7-7 except that lithium bisoxalate borate was not used as 7-1. At that time, the concentration of LiPF _{6 in} the electrolytic solution was 1.00 mol / l. Moreover, vinylene carbonate was used as Comparative Examples 7-1-2, 7-2-2, 7-3-2, 7-4-2, 7-5-2, 7-6-2, and 7-7-2. A secondary battery was fabricated in the same manner as in Examples 7-1 to 7-7, except that it was not used.

Furthermore, as Comparative Examples 7-8-1 to 7-8-3, the amount of the positive electrode active material and the amount of the negative electrode active material are adjusted so that the open circuit voltage at the time of full charge is 4.20V. Other than that described above, secondary batteries were fabricated in the same manner as in Examples 7-1 to 7-7. At that time, in Comparative Example 7-8-2, lithium bisoxalate borate was not used, and the concentration of LiPF _{6 in} the electrolytic solution was set to 1.00 mol / l. In Comparative Example 7-8-3, vinylene carbonate was not used.

  For the fabricated secondary batteries of Examples 7-1 to 7-7 and Comparative Examples 7-1-1 to 7-8-3, charge and discharge were performed, and high-temperature cycle characteristics were examined. Charging is performed in a high-temperature bath set at 45 ° C. with a constant current of 500 mA until the upper limit voltage is reached, then with the constant voltage remaining at the upper limit voltage until the total charging time reaches 5 hours. Was performed at a constant current of 300 mA until the battery voltage reached 3.00V. The high-temperature cycle characteristics are obtained by repeating this charge / discharge, from the discharge capacity maintenance rate at the 100th cycle to the discharge capacity at the second cycle, that is, (discharge capacity at the 100th cycle / discharge capacity at the second cycle) × 100 (%). Asked. The charging upper limit voltage was as shown in Table 9, Table 10, and Table 11. The results are shown in Table 9, Table 10, and Table 11.

As can be seen from Tables 9, 10, and 11, as the positive electrode active material, a lithium composite oxide represented by the average composition shown in Chemical Formula 1 and a lithium composite oxide represented by the average composition shown in Chemical Formula 3 According to Examples 7-1 to 7-7 in which vinylene carbonate, LiPF ₆ and lithium bisoxalate borate were included in the electrolyte, Comparative Example 7-1 in which lithium bisoxalate borate was not used Comparative example in which vinylene carbonate was not used than -1,7-2-1, 7-3-1, 7-4-1, 7-5-1, 7-6-1, 7-7-1 7-1-2, 7-2-2, 7-3-2, 7-4-2, 7-5-2, 7-6-2, 7-7-2, respectively, high temperature cycle characteristics jump Improved. In Comparative Examples 7-8-1 to 7-8-3 in which the charging upper limit voltage was 4.20 V, the effect of using vinylene carbonate, LiPF ₆ and lithium bisoxalate borate was hardly observed.

That is, in a battery having an open circuit voltage in the range of 4.25 V or more and 6.00 V or less during full charge, if the electrolyte contains vinylene carbonate, LiPF ₆ and lithium bisoxalate borate, It was found that the cycle characteristics can be improved even in a high temperature environment.

(Examples 8-1 to 8-7)
The secondary battery was the same as in Examples 7-1 to 7-7 except that LiNi _0.5 Co _0.2 Mn _0.3 O ₂ was not used, that is, only LiCoO ₂ was used as the positive electrode active material. Was made.

Comparative Examples 8-1-1, 8-2-1, 8-3-1, 8-4-1, 8-5-1, 8-6-1, 8- for Examples 8-1 to 8-7 A secondary battery was produced in the same manner as in Examples 8-1 to 8-7 except that lithium bisoxalate borate was not used as 7-1. At that time, the concentration of LiPF _{6 in} the electrolytic solution was 1.00 mol / l. Moreover, vinylene carbonate was used as Comparative Examples 8-1-2, 8-2-2, 8-3-3, 8-4-2, 8-5-2, 8-6-2, and 8-7-2. A secondary battery was fabricated in the same manner as in Examples 8-1 to 8-7, except that it was not used.

Furthermore, as Comparative Examples 8-8-1 to 8-8-3, the amount of the positive electrode active material and the amount of the negative electrode active material are adjusted so that the open circuit voltage at the time of full charge is 4.20V. Except for this, secondary batteries were fabricated in the same manner as in Examples 8-1 to 8-7. At that time, in Comparative Example 8-8-2, lithium bisoxalate borate was not used, and the concentration of LiPF _{6 in} the electrolytic solution was set to 1.00 mol / l. In Comparative Example 8-8-3, vinylene carbonate was not used.

  Regarding the fabricated secondary batteries of Examples 8-1 to 8-7 and Comparative Examples 8-1-1 to 8-8-3, Examples 7-1 to 7-7 and Comparative Examples 7-1-1 to 7-7 The high temperature cycle characteristics were examined in the same manner as in -8-3. The charging upper limit voltage was as shown in Table 12, Table 13, and Table 14. The results are shown in Table 12, Table 13, and Table 14.

  As can be seen from Table 12, Table 13, and Table 14, the same results as in Examples 7-1 to 7-7 were obtained.

That is, in a case where the open circuit voltage at the time of full charge is in the range of 4.25 V or more and 6.00 V or less and the positive electrode 21 includes a lithium composite oxide represented by the average composition shown in Chemical Formula 1 However, it was found that if the electrolyte solution contains vinylene carbonate, LiPF ₆ and lithium bisoxalate borate, the cycle characteristics can be improved even in a high temperature environment.

(Examples 9-1 to 9-5)
Instead of LiNi _0.5 Co _0.2 Mn _0.3 O ₂ , LiNi _0.33 Co _0.33 Mn _0.33 O ₂ , LiNi _0.5 Co _0.2 Mn _0.3 O ₂ F _0.01 , LiNi _0.5 Mn _0.5 O ₂ , LiMn ₂ O ₄ , or LiFePO ₄ was used. Otherwise, a secondary battery was made in the same manner as Example 7-3. Note that LiNi _0.33 Co _0.33 Mn _0.33 O ₂ is a lithium composite oxide represented by the average composition shown in Chemical _{Formula 2} , and LiNi _0.5 Co _0.2 Mn _0.3 O ₂ F _0.01 and LiNi _0.5 Mn _0.5 O ₂ are LiMn ₂ O ₄ is a lithium composite oxide represented by the average composition shown in Chemical formula ₄ , and LiFePO ₄ is the lithium composite phosphoric acid shown in Chemical formula 5. Salt.

  For the fabricated secondary batteries of Examples 9-1 to 9-5, high temperature cycle characteristics were examined in the same manner as in Example 7-3. The results are shown in Table 15.

As can be seen from Table 15, in the same manner as in Example 1-3, instead of LiNi _0.5 Co _0.2 Mn _0.3 O ₂ , LiNi _0.33 Co _0.33 Mn _0.33 O ₂ , LiNi _0.5 Co _0.2 Mn _0.3 O ₂ F _0.01 , LiNi _0.5 In Examples 9-1 to 9-5 using Mn _0.5 O ₂ , LiMn ₂ O ₄ , or LiFePO ₄ , high values were obtained for the high-temperature cycle characteristics.

That is, as the positive electrode active material, the lithium composite oxide represented by the average composition shown in Chemical formula 2, the lithium composite oxide represented by the other average composition shown in Chemical formula 3, and the average composition shown in Chemical formula 4 Even when the lithium composite oxide or the lithium composite phosphate shown in Chemical formula 5 is used, if the electrolyte contains vinylene carbonate, LiPF ₆ and lithium bisoxalate borate, the temperature It was found that the cycle characteristics can be improved even in an environment.

(Examples 10-1 to 10-5)
A secondary battery was made in the same manner as Example 7-3, except that the mixing ratio of LiCoO ₂ and LiNi _0.5 Co _0.2 Mn _0.3 O ₂ was changed. And LiCoO _2, proportions by weight ratio of the _{LiNi 0.5 Co 0.2 Mn 0.3 O 2} (LiCoO 2: LiNi 0.5 Co 0.2 Mn 0.3 O 2) is to 20:80 in Example 10-1, Example 10-2 50:50, 70:30 in Example 10-3, 90:10 in Example 10-4, and 95: 5 in Example 10-5.

  For the fabricated secondary batteries of Examples 10-1 to 10-5, the high temperature cycle characteristics were examined in the same manner as in Example 7-3. The results are shown in Table 16.

As can be seen from Table 16, also in Examples 10-1 to 10-5 in which the mixing ratio of LiCoO ₂ and LiNi _0.5 Co _0.2 Mn _0.3 O ₂ was changed as in Example 7-3, A high value was obtained.

  That is, the lithium composite oxide represented by the average composition shown in Chemical Formula 1, the lithium composite oxide represented by the average composition shown in Chemical Formula 2, and the lithium composite oxide represented by the average composition shown in Chemical Formula 3 , Even if the mixing ratio of at least one selected from the group consisting of the lithium composite oxide represented by the average composition shown in Chemical formula 4 and the lithium composite phosphate shown in Chemical formula 5 is changed, It was found that the characteristics can be improved.

(Examples 11-1 to 11-6)
A secondary battery was made in the same manner as Example 7-3 except that the concentration of lithium bisoxalate borate in the electrolytic solution was changed. At that time, the concentration of lithium bisoxalate borate in the electrolytic solution was 0.5 mol / kg in Example 11-1, 0.3 mol / kg in Example 11-2, and 0.1 mol in Example 11-3. / Kg, 0.05 mol / kg in Example 11-4, 0.001 mol / kg in Example 11-5, and 0.0005 mol / kg in Example 11-6. The total concentration of the electrolyte salt in the electrolytic solution was 1.00 mol / l.

  For the fabricated secondary batteries of Examples 11-1 to 11-6, the high temperature cycle characteristics were examined in the same manner as in Example 7-3. The results are shown in Table 17.

  As can be seen from Table 17, the high-temperature cycle characteristics increased as the concentration of lithium bisoxalate borate in the electrolytic solution increased, and showed a tendency to decrease after showing a maximum value.

  That is, it has been found that it is preferable to adjust the concentration of lithium bisoxalate borate in the electrolytic solution to 0.0005 mol / kg or more and 0.3 mol / kg or less.

(Examples 12-1 to 12-4)
A secondary battery was fabricated in the same manner as in Example 7-3 except that the content of vinylene carbonate in the electrolytic solution was 10% by mass, 5% by mass, 2% by mass, or 0.1% by mass. .

  For the fabricated secondary batteries of Examples 12-1 to 12-4, the high temperature cycle characteristics were examined in the same manner as in Example 7-3. The results are shown in Table 18.

  As can be seen from Table 18, the high-temperature cycle characteristics increased as the content of vinylene carbonate in the electrolytic solution increased, and a tendency to decrease after showing the maximum value was observed.

  That is, it has been found that it is preferable if the content of vinylene carbonate in the electrolytic solution is 0.1% by mass or more and 10% by mass or less.

  Although the present invention has been described with reference to the embodiments and examples, the present invention is not limited to the above embodiments and examples, and various modifications can be made. For example, in the above-described embodiments and examples, the secondary battery having a winding structure has been described. However, the present invention is similarly applied to a secondary battery having a structure in which the positive electrode and the negative electrode are folded or stacked. be able to. In addition, the present invention can also be applied to a secondary battery having a shape such as a so-called coin type, button type, square type, or laminate film type.

  Further, although cases have been described with the above embodiment and examples where an electrolytic solution is used, the present invention can also be applied to cases where other electrolytes are used. Examples of other electrolytes include so-called gel electrolytes in which an electrolytic solution is held in a polymer compound.

  Furthermore, in the above-described embodiments and examples, a so-called lithium ion secondary battery in which the capacity of the negative electrode is represented by a capacity component due to insertion and extraction of lithium has been described. The capacity of the negative electrode used is a so-called lithium metal secondary battery whose capacity is represented by the deposition and dissolution of lithium, or the negative electrode material capable of occluding and releasing lithium is more charged than the positive electrode. The same applies to a secondary battery in which the capacity of the negative electrode includes a capacity component due to insertion and extraction of lithium and a capacity component due to precipitation and dissolution of lithium, and is expressed by the sum thereof, by reducing the capacity. be able to.

It is sectional drawing showing the structure of the secondary battery which concerns on one embodiment of this invention. It is sectional drawing which expands and represents a part of winding electrode body in the secondary battery shown in FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Battery can, 12, 13 ... Insulation board, 14 ... Battery cover, 15 ... Safety valve mechanism, 15A ... Disc board, 16 ... Heat sensitive resistance element, 17 ... Gasket, 20 ... Winding electrode body, 21 ... Positive electrode, 21A ... positive electrode current collector, 21B ... positive electrode active material layer, 22 ... negative electrode, 22A ... negative electrode current collector, 22B ... negative electrode active material layer, 23 ... separator, 24 ... center pin, 25 ... positive electrode lead, 26 ... negative electrode lead

Claims (8)

A battery comprising an electrolyte solution together with a positive electrode and a negative electrode,
The open circuit voltage in a fully charged state per pair of positive electrode and negative electrode is in the range of 4.25V to 6.00V,
The positive electrode includes a lithium composite oxide represented by the average composition shown in Chemical Formula 1, a lithium composite oxide represented by the average composition shown in Chemical Formula 2, and a lithium composite oxide represented by the average composition shown in Chemical Formula 3 At least one selected from the group consisting of lithium composite oxides represented by the average composition shown in Chemical Formula 4 and lithium composite phosphates shown in Chemical Formula 5;
The electrolytic solution includes vinylene carbonate, LiPF ₆ , and lithium bisoxalate borate.
(Chemical formula 1)
Li _r Co _(1-s) M3 _s O _{(2-t) Fu}
(In the formula, M3 is nickel (Ni), manganese (Mn), magnesium (Mg), aluminum (Al), boron (B), titanium (Ti), vanadium (V), chromium (Cr), iron (Fe ), Copper (Cu), zinc (Zn), zirconium (Zr), molybdenum (Mo), tin (Sn), calcium (Ca), strontium (Sr), and tungsten (W). R, s, t, and u are ranges of 0.8 ≦ r ≦ 1.2, 0 ≦ s <0.5, −0.1 ≦ t ≦ 0.2, and 0 ≦ u ≦ 0.1. Is the value in.)
(Chemical formula 2)
Li _f Mn _(1-gh) Ni _g M1 _h O _(2-j) F _k
(In the formula, M1 is cobalt (Co), magnesium (Mg), aluminum (Al), boron (B), titanium (Ti), vanadium (V), chromium (Cr), iron (Fe), copper (Cu ), Zinc (Zn), zirconium (Zr), molybdenum (Mo), tin (Sn), calcium (Ca), strontium (Sr), and tungsten (W). g, h, j and k are 0.8 ≦ f ≦ 1.2, 0 <g <0.5, 0 ≦ h ≦ 0.5, g + h <1, −0.1 ≦ j ≦ 0.2, (It is a value within the range of 0 ≦ k ≦ 0.1.)
(Chemical formula 3)
Li _m Ni _(1-n) M2 _n O _(2-p) F _q
(Wherein M2 is cobalt (Co), manganese (Mn), magnesium (Mg), aluminum (Al), boron (B), titanium (Ti), vanadium (V), chromium (Cr), iron (Fe ), Copper (Cu), zinc (Zn), zirconium (Zr), molybdenum (Mo), tin (Sn), calcium (Ca), strontium (Sr), and tungsten (W). M, n, p and q are 0.8 ≦ m ≦ 1.2, 0.005 ≦ n ≦ 0.5, −0.1 ≦ p ≦ 0.2, 0 ≦ q ≦ 0.1. It is a value within the range.)
(Chemical formula 4)
Li _v Mn _2-w M4 _w O _x F _y
(In the formula, M4 is cobalt (Co), nickel (Ni), magnesium (Mg), aluminum (Al), boron (B), titanium (Ti), vanadium (V), chromium (Cr), iron (Fe ), Copper (Cu), zinc (Zn), molybdenum (Mo), tin (Sn), calcium (Ca), strontium (Sr), and tungsten (W). w, x, and y are values within a range of 0.9 ≦ v ≦ 1.1, 0 ≦ w ≦ 0.6, 3.7 ≦ x ≦ 4.1, and 0 ≦ y ≦ 0.1. )
(Chemical formula 5)
Li _z M5PO ₄
(In the formula, M5 is cobalt (Co), manganese (Mn), iron (Fe), nickel (Ni), magnesium (Mg), aluminum (Al), boron (B), titanium (Ti), vanadium (V ), Niobium (Nb), copper (Cu), zinc (Zn), molybdenum (Mo), calcium (Ca), strontium (Sr), tungsten (W), and zirconium (Zr). Z is a value in the range of 0.9 ≦ z ≦ 1.1.) 2. The battery according to claim 1, wherein a concentration of lithium bisoxalate borate in the electrolytic solution is 0.0005 mol / kg or more and 0.3 mol / kg or less.   The battery according to claim 1, wherein the content of vinylene carbonate in the electrolytic solution is in the range of 0.1% by mass to 10% by mass.   The battery according to claim 1, wherein an open circuit voltage in a fully charged state per pair of positive electrode and negative electrode is in a range of 4.25V to 4.60V. A battery comprising an electrolyte solution together with a positive electrode and a negative electrode,
The open circuit voltage in a fully charged state per pair of positive electrode and negative electrode is in the range of 4.25V to 6.00V,
The positive electrode includes a lithium composite oxide represented by the average composition shown in Chemical Formula 1, a lithium composite oxide represented by the average composition shown in Chemical Formula 2, and a lithium composite oxide represented by the average composition shown in Chemical Formula 3 An oxide, at least one selected from the group consisting of a lithium composite oxide represented by the average composition shown in Chemical formula 4 and a lithium composite phosphate shown in Chemical formula 5,
The electrolytic solution includes vinylene carbonate, LiPF ₆ , and LiBF ₄ .
(Chemical formula 1)
Li _r Co _(1-s) M3 _s O _{(2-t) Fu}
(In the formula, M3 is nickel (Ni), manganese (Mn), magnesium (Mg), aluminum (Al), boron (B), titanium (Ti), vanadium (V), chromium (Cr), iron (Fe ), Copper (Cu), zinc (Zn), zirconium (Zr), molybdenum (Mo), tin (Sn), calcium (Ca), strontium (Sr), and tungsten (W). R, s, t, and u are ranges of 0.8 ≦ r ≦ 1.2, 0 ≦ s <0.5, −0.1 ≦ t ≦ 0.2, and 0 ≦ u ≦ 0.1. Is the value in.)
(Chemical formula 2)
Li _f Mn _(1-gh) Ni _g M1 _h O _(2-j) F _k
(In the formula, M1 is cobalt (Co), magnesium (Mg), aluminum (Al), boron (B), titanium (Ti), vanadium (V), chromium (Cr), iron (Fe), copper (Cu ), Zinc (Zn), zirconium (Zr), molybdenum (Mo), tin (Sn), calcium (Ca), strontium (Sr), and tungsten (W). g, h, j and k are 0.8 ≦ f ≦ 1.2, 0 <g <0.5, 0 ≦ h ≦ 0.5, g + h <1, −0.1 ≦ j ≦ 0.2, (It is a value within the range of 0 ≦ k ≦ 0.1.)
(Chemical formula 3)
Li _m Ni _(1-n) M2 _n O _(2-p) F _q
(Wherein M2 is cobalt (Co), manganese (Mn), magnesium (Mg), aluminum (Al), boron (B), titanium (Ti), vanadium (V), chromium (Cr), iron (Fe ), Copper (Cu), zinc (Zn), zirconium (Zr), molybdenum (Mo), tin (Sn), calcium (Ca), strontium (Sr), and tungsten (W). M, n, p and q are 0.8 ≦ m ≦ 1.2, 0.005 ≦ n ≦ 0.5, −0.1 ≦ p ≦ 0.2, 0 ≦ q ≦ 0.1. It is a value within the range.)
(Chemical formula 4)
Li _v Mn _2-w M4 _w O _x F _y
(In the formula, M4 is cobalt (Co), nickel (Ni), magnesium (Mg), aluminum (Al), boron (B), titanium (Ti), vanadium (V), chromium (Cr), iron (Fe ), Copper (Cu), zinc (Zn), molybdenum (Mo), tin (Sn), calcium (Ca), strontium (Sr), and tungsten (W). w, x, and y are values within a range of 0.9 ≦ v ≦ 1.1, 0 ≦ w ≦ 0.6, 3.7 ≦ x ≦ 4.1, and 0 ≦ y ≦ 0.1. )
(Chemical formula 5)
Li _z M5PO ₄
(In the formula, M5 is cobalt (Co), manganese (Mn), iron (Fe), nickel (Ni), magnesium (Mg), aluminum (Al), boron (B), titanium (Ti), vanadium (V ), Niobium (Nb), copper (Cu), zinc (Zn), molybdenum (Mo), calcium (Ca), strontium (Sr), tungsten (W), and zirconium (Zr). Z is a value in the range of 0.9 ≦ z ≦ 1.1.) The battery according to claim 5, wherein the concentration of LiBF _{4 in} the electrolytic solution is 0.0005 mol / kg or more and 0.3 mol / kg or less.   The battery according to claim 5, wherein the content of vinylene carbonate in the electrolytic solution is in the range of 0.1% by mass to 10% by mass. 6. The battery according to claim 5, wherein an open circuit voltage in a fully charged state per pair of positive electrode and negative electrode is in a range of 4.25V to 4.60V.

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