JP2008186770A - Nonaqueous electrolyte battery, battery pack and automobile - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a nonaqueous electrolyte battery, a battery pack and an automobile, which have excellent overcharge cycle performance. <P>SOLUTION: The nonaqueous electrolyte battery is characterized by provision of: a positive electrode 3; a negative electrode 4 containing a negative-electrode active material whose average activation potential is 0.6 V or higher with respect to a potential of metallic lithium; and a nonaqueous electrolyte including ceric ions and anions consisting of at least one selected from a group of PF<SB>6</SB><SP>-</SP>, BF<SB>4</SB><SP>-</SP>, ClO<SB>4</SB><SP>-</SP>, CF<SB>3</SB>SO<SB>3</SB><SP>-</SP>, N(CF<SB>3</SB>SO<SB>2</SB>)<SB>2</SB><SP>-</SP>, N(C<SB>2</SB>F<SB>5</SB>SO<SB>2</SB>)<SP>-</SP>and N(CF<SB>3</SB>SC(C<SB>2</SB>F<SB>5</SB>SO<SB>2</SB>)<SB>3</SB>)<SP>-</SP>. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a nonaqueous electrolyte battery, a battery pack using the nonaqueous electrolyte battery, and an automobile.

  In recent years, due to rapid technological development in the electronics field, electronic devices are becoming smaller and lighter. As a result, electronic devices have become more portable and cordless, and secondary batteries serving as driving sources are also desired to be smaller, lighter, and have higher energy density. In response to such demands, lithium secondary batteries with high energy density have been developed.

  When a rechargeable lithium battery is overcharged due to an overcharged battery voltage, the non-aqueous electrolyte may decompose in the cell, and the battery function is likely to deteriorate due to gas generation or the attachment of electrodes of decomposed products. Are known. In addition, since an organic solvent is used for the non-aqueous electrolyte, the safety tends to be particularly lowered.

  As a method for avoiding such a problem, when the inside of the cell reaches a predetermined temperature or more, the polymer compound constituting the separator causes a glass transition to close the gap of the separator, and the ion conduction between the positive electrode and the negative electrode is shut down. A method of charging a temperature sensing element in a cell has been proposed. However, when the battery becomes large, when the separator is shut down, the glass transition may not be in time for the heat generation rate, and the temperature sensing element may cause a decrease in the energy density and power density of the battery. Furthermore, these means are means for ensuring safety by losing the battery function when the battery is exposed to overcharge, and are positioned as final means.

  In order to use a large-sized device such as a vehicle or a robot in a cordless manner in the future, it is assumed that a high voltage is obtained by using an assembled battery in which a plurality of batteries are connected in series. At that time, it is conceivable that the charging state of the unit battery constituting the assembled battery varies due to the influence of temperature or the like. However, the function as the assembled battery is affected, and in the worst case, it may fall into the above-mentioned dangerous situation. .

Patent Document 1 discloses a nonaqueous electrolyte secondary battery using a metal material mainly composed of lithium for the negative electrode or a carbon material that can be doped and dedoped with lithium, and a composite oxide of lithium and a transition metal for the positive electrode. In order to prevent charging, it is described that a non-aqueous electrolyte contains a metal ion or a metal complex having a redox potential of 3.8 V to 4.8 V with respect to lithium. Examples of the metal complex include Ce (NH ₄ ) ₂ (NO ₃ ) ₅ and Ce (NO ₃ ) ₃ .

However, Ce (NH ₄ ) ₂ (NO ₃ ) ₅ and Ce (NO ₃ ) ₃ cause gas generation as a result of the oxidation-reduction reaction in the secondary battery, or the counter ion of Ce is an aluminum current collector. Since the body may be corroded, the overdischarge cycle performance is inferior.

  On the other hand, Patent Document 2 describes that an oxidation-reduction chemical shuttle is added to an electrolytic solution in order to improve resistance to repeated overcharge of a lithium ion secondary battery. Specific examples of the redox chemical shuttle include anisole and methoxybenzene.

However, the redox chemical shuttle described in Patent Document 2 is poor in solubility in a non-aqueous solvent, and has a problem in overcharge cycle performance at a low temperature or a large current.
JP-A-6-338347 US2005 / 0221196A1

  An object of the present invention is to provide a nonaqueous electrolyte battery, a battery pack, and an automobile excellent in overcharge cycle performance.

A first nonaqueous electrolyte battery according to the present invention includes a positive electrode,
A negative electrode containing a negative electrode active material having an average operating potential of 0.6 V or more with respect to the potential of metallic lithium;
Cerium ions, PF ₆ ⁻ , BF ₄ ⁻ , ClO ₄ ⁻ , CF ₃ SO ₃ ⁻ , N (CF ₃ SO ₂ ) ₂ ⁻ , N (C ₂ F ₅ SO ₂ ) ⁻ and (N (CF ₃ SC ( And a non-aqueous electrolyte containing at least one anion selected from the group consisting of C ₂ F ₅ SO ₂ ) ₃ ) ^- .

A second nonaqueous electrolyte battery according to the present invention includes a positive electrode,
A negative electrode comprising a negative electrode active material having an average operating potential exceeding 0.4 V with respect to the potential of metallic lithium;
And a nonaqueous electrolyte containing a carbonyl compound having a redox potential (relative to the potential of metallic lithium) of 0.4 V or more and less than the average operating potential of the negative electrode.

A third nonaqueous electrolyte battery according to the present invention includes a positive electrode,
A negative electrode comprising lithium titanate or iron sulfide;
Trans-2-butenal, 2-cyclohexane-1-one, 2-ethoxy-2-cyclohexane-1-one, 1-formylcyclohexene, trans-2,2,6,6-tetramethyl-4-heptone-3- At least one selected from the group consisting of ON, 2-methoxy-2-acetylcyclohexanone, benzophenone, 5,5-dimethoxy-3-isobutoxy-2-cyclohexane-1-one and 1-acetyl-4-tert-butylcyclohexane And a non-aqueous electrolyte containing various types of carbonyl compounds.

  The battery pack according to the present invention includes at least one of the first to third nonaqueous electrolyte batteries.

  The automobile according to the present invention includes at least one of the first to third non-aqueous electrolyte batteries described above.

  According to the present invention, a nonaqueous electrolyte battery, a battery pack, and an automobile excellent in overcharge cycle performance are provided.

(First embodiment)
In a nonaqueous electrolyte battery, lithium is desorbed from the positive electrode during charging, and lithium is accumulated in the negative electrode via the electrolyte. At that time, if charging proceeds at a voltage higher than normal, the positive electrode becomes excessively lithium-deficient and the crystal structure becomes unstable, and the overcharged positive electrode generates heat to decompose the nonaqueous electrolyte. . Further, since the potential of the negative electrode tends to be low, precipitation of lithium and decomposition of the negative electrode occur, and decomposition of the nonaqueous electrolyte also occurs and heat is generated. As a result, the battery becomes unsafe.

In the nonaqueous electrolyte battery including a negative electrode including a negative electrode active material in which the average operating potential of the negative electrode is 0.6 V or more with respect to the potential of metallic lithium, the present inventors have added cerium ions and PF to the nonaqueous electrolyte. ₆ ⁻ , BF ₄ ⁻ , ClO ₄ ⁻ , CF ₃ SO ₃ ⁻ , N (CF ₃ SO ₂ ) ₂ ⁻ , N (C ₂ F ₅ SO ₂ ) ⁻ and (N (CF ₃ SC (C ₂ F ₅ SO _{2) 3)} ^- by the inclusion of an anion consisting of at least one selected from the group consisting of, it is possible to prevent ignition due to heat generation during overcharging, since overcharging cycle performance was found to be improved is there.

  FIG. 1 shows the relationship between the redox potential for metallic lithium and the redox potential for cerium ions with respect to the metallic lithium potential of the negative electrode containing carbon, the negative electrode containing lithium titanate, and the positive electrode when fully charged. When the redox potential of the positive electrode exceeds 4.25V and reaches 4.64V due to overcharging, cerium ions are oxidized from trivalent to tetravalent. Thereby, since the lithium desorption reaction from the positive electrode is suppressed, ignition due to heat generation during overcharge can be prevented.

  Tetravalent cerium ions are reduced at the negative electrode to return to trivalent. By using a negative electrode active material in which the negative electrode average operating potential is 0.6 V or more with respect to the potential of metallic lithium, the negative potential reaches 0.55 V, the reaction potential at which trivalent cerium ions change to cerium metal. It becomes difficult and precipitation of cerium metal can be avoided. Since cerium metal does not dissolve in the non-aqueous electrolyte, overdischarge cycle performance can be improved by avoiding precipitation of cerium metal.

That is, when the battery is overcharged, trivalent cerium ions are oxidized at the positive electrode, and the oxidized tetravalent cerium ions are convected or diffused to the negative electrode and reduced in the battery. In other words, the possibility of overcharging can be reduced by reducing the current that should be spent for charging. Also, counter ions of cerium ions, such as PF ₆ ⁻ , BF ₄ ⁻ , ClO ₄ ⁻ , CF ₃ SO ₃ ⁻ , N (CF ₃ SO ₂ ) ₂ ⁻ , N (C ₂ F ₅ SO ₂ ) ⁻ and ( Since at least one selected from the group consisting of N (CF ₃ SC (C ₂ F ₅ SO ₂ ) ₃ ) ⁻ can function as an electrolyte, there is no risk of gas generation. The anion components in them are PF ₆ ⁻ , BF ₄ ⁻ , ClO ₄ ⁻ , CF ₃ SO ₃ ⁻ , N (CF ₃ SO ₂ ) ₂ ⁻ , N (C ₂ F ₅ SO ₂ ) ⁻ and (N (CF ₃ By using at least one selected from the group consisting of SC (C ₂ F ₅ SO ₂ ) ₃ ) ^−, not only the safety during overcharge but also the overdischarge cycle performance can be improved.

Cerium ions and the above-mentioned types of anions include, for example, Ce (PF ₆ ) ₃ , Ce (BF ₄ ) ₃ , Ce (ClO ₄ ) ₃ , Ce (CF ₃ SO ₃ ) ₃ , Ce (N (CF ₃ SO ₂ ) ₂ ) ₃ , Ce (N (C ₂ F ₅ SO ₂ )) ₃ , Ce (N (CF ₃ SC (C ₂ F ₅ SO ₂ ) ₃ ) ₃ ) (hereinafter referred to as first overcharge preventive agent) (Referred to as “oxidation-type overcharge inhibitor”) The type of the first overcharge inhibitor may be one kind or a mixture of two or more kinds. It is very effective because it is a compound that sets the redox potential of cerium ion in the battery to about 0.2 V, which is the normal range of positive electrode charging. The first overcharge preventive agent can be used as a first overcharge preventive agent. This is a compound that has a reversible redox potential at a potential nobler than the potential, and that does not have a redox potential between the positive and negative electrode charging potentials. Absent.

  The amount of the first overcharge inhibitor added is preferably 0.001 mol / L or more and 4 mol / L or less. If it is less than 0.001 mol / L, since the current flowing through the first overcharge inhibitor is small, a sufficient overcharge prevention effect cannot be expected. On the other hand, when it exceeds 4 mol / L, there are too many solutes, and the viscosity of the non-aqueous electrolyte is improved, so that it becomes difficult for current to flow, and the effect of preventing overcharge is reduced. More preferably, it is the range of 0.1 mol / L or more and 3 mol / L or less.

  Since the first overcharge inhibitor acts first on the positive electrode during charging, it is desirable to use it when the negative electrode capacity in which the negative electrode potential easily changes is larger than the positive electrode capacity. The capacitance of each electrode is determined by which potential has changed greatly at the end of charging when each electrode is taken out and charged to the voltage specified by the method of use. In other words, the larger the change, the smaller the capacity. In order to obtain a sufficient effect, it is desirable that the ratio of the negative electrode capacity to the positive electrode capacity (negative electrode / positive electrode) be 1.001 or more and 1.400 or less.

  The composition of the first overcharge inhibitor can be confirmed by evaporating and drying a nonaqueous electrolyte obtained by disassembling the nonaqueous electrolyte battery, and conducting a composition analysis of the resulting precipitate.

  Hereinafter, the positive electrode, the negative electrode, the separator, the nonaqueous electrolyte, and the exterior material of the nonaqueous electrolyte battery according to the first embodiment will be described.

1) Positive electrode The positive electrode includes a positive electrode current collector and a positive electrode layer that is supported on one or both surfaces of the positive electrode current collector and includes an active material and a binder.

  Examples of the positive electrode current collector include aluminum or an aluminum alloy.

Examples of the positive electrode active material include various oxides and sulfides. For example, manganese dioxide (MnO ₂ ), iron oxide, copper oxide, nickel oxide, lithium manganese composite oxide (eg, Li _x Mn ₂ O ₄ or Li _x MnO ₂ ), lithium nickel composite oxide (eg, Li _x NiO ₂ ) , lithium-cobalt composite oxide (Li _x CoO _2), lithium nickel cobalt composite oxide (e.g., _{LiNi 1-y Co y O 2} ), lithium manganese cobalt composite oxides (e.g. _{LiMn y Co 1-y O 2} ), spinel type lithium-manganese-nickel composite oxide _{(Li x Mn 2-y Ni} y O 4), lithium phosphates having an olivine structure _{(Li x FePO 4, Li x} Fe 1-y Mn y PO 4, Li x CoPO 4 etc. ), Iron sulfate (Fe ₂ (SO ₄ ) ₃ ), vanadium oxide (for example, V ₂ O ₅ ), and the like. X and y are preferably in the range of 0 to 1.

  In addition, conductive polymer materials such as polyaniline and polypyrrole, disulfide-based polymer materials, organic materials such as sulfur (S) and carbon fluoride, and inorganic materials are also included. More preferable positive electrode active materials for secondary batteries include lithium manganese composite oxide, lithium nickel composite oxide, lithium cobalt composite oxide, lithium nickel cobalt composite oxide, spinel type lithium manganese nickel composite oxide, lithium manganese cobalt. Examples include composite oxides and lithium iron phosphate. This is because a high battery voltage can be obtained with these positive electrode active materials.

  The positive electrode active material is preferably a compound having a positive electrode average operating potential lower than the oxidation potential of cerium ions (trivalent) (4.64 V with respect to the metal lithium potential). This is because if the average operating potential of the positive electrode exceeds the oxidation potential of cerium ions, an oxidation reaction of cerium ions occurs during normal charge and discharge, and charge / discharge performance may be impaired. The average operating potential of the positive electrode in this case is a value obtained by dividing the charge / discharge electric energy by the charge / discharge electricity amount when charging / discharging at the upper limit and lower limit of the charge / discharge potential of the positive electrode when charging / discharging in the recommended operating voltage range of the battery. Say.

  A more preferable positive electrode active material is a compound having a positive electrode operating potential upper limit lower than the oxidation potential of cerium ions (trivalent) (4.64 V with respect to the metal lithium potential). This is because if the upper limit of the operating potential of the positive electrode exceeds the oxidation potential of cerium ions, an oxidation reaction of cerium ions may occur during normal charge / discharge, and charge / discharge performance may be impaired. The upper limit of the operating potential of the positive electrode in this case refers to the upper limit of the charging / discharging potential of the positive electrode when charged and discharged within the recommended operating voltage range of the battery.

In the case where a composite oxide containing at least one of cobalt, nickel and manganese and lithium, or iron phosphate is used as the positive electrode active material, the upper limit of the positive electrode operating potential is 4.2 to 4.4 V, and the lower limit is 3.7 to 2 V. Become. The average operating potential is 4.1 to 3.2V. In order to obtain a high voltage, it is preferable to set the average operating potential of the positive electrode to 3 V or more. Examples of such positive electrode active materials include lithium cobaltate (Li _x CoO ₂ ), a part of the cobalt component of lithium cobaltate, other transition elements, Al, Sn, B, F, Mg, Si, S, and the like. An oxide substituted with at least one element selected from the group consisting of P, lithium nickelate (Li _x NiO ₂ ), a part of the nickel component of lithium nickelate, other transition elements, Al, Sn, B, Oxide substituted with at least one element selected from the group consisting of F, Mg, Si, S and P, lithium manganate (Li _x Mn ₂ O ₄ or Li _x MnO ₂ ), manganese component of lithium manganate An oxide in which a part of is substituted with at least one element selected from the group consisting of other transition elements, Al, Sn, B, F, Mg, Si, S and P, lithium iron phosphate ( i _x FePO ₄₎ and other transition elements some of the iron components of the lithium iron phosphate, Al, Sn, B, F , Mg, Si, at least one element selected from the group consisting of S and P Examples include substituted oxides. The kind of positive electrode active material to be used can be one kind or two kinds or more.

  Examples of the conductive agent include acetylene black, carbon black, and graphite.

  Examples of the binder include polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVdF), and fluorine-based rubber.

  The compounding ratio of the positive electrode active material, the conductive agent and the binder is preferably in the range of 80 to 95% by weight of the positive electrode active material, 3 to 18% by weight of the conductive agent, and 2 to 17% by weight of the binder.

The basis weight of the positive electrode layer is desirably 30 g / m ² or more and 120 g / m ² or less. When the weight per unit area of the positive electrode layer exceeds 120 g / m ² , charging with a large current is difficult, so that it is not suitable for a large current charging application. Moreover, since the capacity density of a battery is low as the fabric weight of a positive electrode layer is less than 30 g / m < ² >, there are few uses. A more preferable range is 40 g / m ² or more and 100 g / m ² or less.

2) Negative electrode A negative electrode layer containing a negative electrode active material having an average operating potential of the negative electrode of 0.6 V or more is supported on one surface or both surfaces of the negative electrode current collector.

  The negative electrode current collector can be formed from, for example, aluminum, copper, nickel, an aluminum alloy, a copper alloy, or a nickel alloy.

As the negative electrode active material, a material having an average operating potential of the negative electrode of 0.6 V or more is used. For example, iron sulfide, iron oxide, titanium oxide, lithium titanate, nickel oxide, cobalt oxide, tungsten oxide, molybdenum oxide, titanium sulfide, or the like can be used. Lithium titanate that can provide excellent cycle performance is desirable. A lithium titanate having a spinel structure or a ramsdellite structure can be used. Examples of the lithium titanate having a spinel structure include Li _{4 + x} Ti ₅ O ₁₂ (x varies in the range of 0 ≦ x ≦ 3 due to charge / discharge reaction). On the other hand, examples of lithium titanate having a ramsdellite structure include Li _{2 + y} Ti ₃ O ₇ (y changes in a range of 0 ≦ y ≦ 3 due to charge / discharge reaction). The average operating potential of the negative electrode in this case is a value obtained by dividing the charge / discharge electric energy by the charge / discharge electric energy when charging / discharging at the upper limit and lower limit of the charge / discharge potential of the negative electrode when charging / discharging in the recommended operating voltage range of the battery. Say.

  When the negative electrode active material is a composite oxide with lithium containing at least titanium (for example, lithium titanate), the negative electrode average operating potential is 1.5V to 1.6V. On the other hand, when the negative electrode active material is iron sulfide, the negative electrode average operating potential is 1.75V.

  A more preferable negative electrode active material is a compound having a lower negative electrode operating potential lower than the reduction potential of cerium ions (trivalent) (0.6 V with respect to the lithium metal potential). This is because if the lower limit of the operating potential of the negative electrode is lower than the reduction potential of cerium ions, the reduction reaction of cerium ions may occur during normal charge / discharge, and the charge / discharge performance may be impaired. The lower limit of the operating potential of the negative electrode in this case refers to the lower limit of the charging / discharging potential of the negative electrode when charged and discharged within the recommended operating voltage range of the battery.

The surface area of the lithium titanate is preferably 1 to 10 m ² / g. When the surface area is less than 1 m ² / g, the effective area contributing to the electrode reaction is small, and the large current discharge characteristics may be deteriorated. On the other hand, if the surface area exceeds 10 m ² / g, the amount of reaction with the non-aqueous electrolyte increases, so that the charge / discharge efficiency may be lowered and gas generation during storage may be induced.

  The negative electrode is produced by suspending a conductive agent and a binder in a suitable solvent in a negative electrode active material, and applying this suspension to a current collector, drying and pressing to form a strip electrode.

  A carbonaceous material is used as the conductive agent.

  Examples of the binder include polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVdF), and fluorine-based rubber.

  The mixing ratio of the negative electrode active material, the conductive agent and the binder is preferably in the range of 70 to 96% by weight of the negative electrode active material, 2 to 28% by weight of the conductive agent, and 2 to 28% by weight of the binder. By setting the amount of the conductive agent to 2% by weight or more, sufficient current collecting performance can be obtained, so that excellent large current characteristics can be obtained. Further, by setting the amount of the binder to 2% by weight or more, the binding strength between the negative electrode layer and the current collector becomes sufficient, and excellent cycle performance can be obtained. On the other hand, from the viewpoint of increasing the capacity, the amount of the conductive agent and the binder is preferably 28% by weight or less.

The basis weight of the negative electrode layer is preferably 30 g / m ² or more and 120 g / m ² or less. When the weight per unit area of the negative electrode layer exceeds 120 g / m ² , it is difficult to charge with a large current, which is unsuitable for a large current charging application. Moreover, since the capacity density of a battery is low as the basis weight of a negative electrode layer is less than 30 g / m < ² >, there are few uses. A more preferable range is 40 g / m ² or more and 100 g / m ² or less.

3) Separator A separator may be disposed between the positive electrode and the negative electrode. A porous separator is used as the separator.

  Examples of the porous separator include a porous film containing polyethylene, polypropylene, cellulose, or polyvinylidene fluoride (PVdF), and a synthetic resin nonwoven fabric. Among these, a porous film made of polyethylene, polypropylene, or both is preferable because it can improve the safety of the secondary battery.

4) Nonaqueous electrolyte A nonaqueous electrolyte to which the first overcharge inhibitor is added will be described. As the non-aqueous electrolyte, a liquid non-aqueous electrolyte (non-aqueous electrolyte) can be used. The nonaqueous electrolytic solution is prepared by dissolving an electrolyte in an organic solvent.

Examples of the electrolyte include lithium perchlorate (LiClO ₄ ), lithium hexafluorophosphate (LiPF ₆ ), lithium tetrafluoroborate (LiBF ₄ ), lithium hexafluoroarsenide (LiAsF ₆ ), and trifluorometa. Examples thereof include lithium salts such as lithium sulfonate (LiCF ₃ SO ₃ ) and bistrifluoromethylsulfonylimitolithium [LiN (CF ₃ SO ₂ ) ₂ ].

  The electrolyte is preferably dissolved in the range of 0.5 mol / L or more and 2.0 mol / L or less with respect to the organic solvent.

  Examples of organic solvents include cyclic carbonates such as ethylene carbonate (EC), propylene carbonate (PC), and vinylene carbonate (VC), chains such as dimethyl carbonate (DMC), methyl ethyl carbonate (MEC), and diethyl carbonate (DEC). Cyclic ethers such as linear carbonate, tetrahydrofuran (THF), and 2-methyltetrahydrofuran (2MeTHF), chain ethers such as dimethoxyethane (DME), γ-butyrolactone (GBL), acetonitrile (AN), sulfolane (SL), etc. Can do. These organic solvents can be used alone or in the form of a mixture of two or more. In particular, it is desirable to use two or more kinds of mixed solvents selected from the group consisting of EC, PC, GBL, DEC, DMC, and MEC.

  Moreover, a room temperature molten salt containing lithium ions can be used as the non-aqueous electrolyte. The room temperature molten salt refers to a salt that is at least partially in a liquid state at room temperature, and the room temperature refers to a temperature range in which a power supply is assumed to normally operate. The temperature range in which the power supply is assumed to normally operate has an upper limit of about 120 ° C. and in some cases about 60 ° C., and a lower limit of about −40 ° C. and in some cases about −20 ° C.

As a lithium salt provided with lithium ions, a lithium salt having a wide potential window, which is generally used for nonaqueous electrolyte batteries, is used. For example, LiBF ₄ , LiPF ₆ , LiClO ₄ , LiCF ₃ SO ₃ , LiN (CF ₃ SO ₂ ) ₂ , LiN (C ₂ F ₅ SO ₂ ), LiN (CF ₃ SC (C ₂ F ₅ SO ₂ ) _3, etc. However, these are not limited, and these may be used alone or in combination of two or more.

  The lithium salt content is preferably 0.1 mol / L or more and 3 mol / L or less, particularly preferably 1 mol / L or more and 2 mol / L or less. When the lithium salt content is less than 0.1 mol / L, the resistance of the electrolyte is large, and the large current / low temperature discharge characteristics decrease. When the lithium salt content exceeds 3.0 mol / L, the melting point of the electrolyte rises and is liquid at room temperature. This is because it becomes difficult to keep the balance.

  The room temperature molten salt has, for example, a quaternary ammonium organic cation having a skeleton represented by the formula (1) or an imidazolium cation having a skeleton represented by the formula (2).

R1 and R2 in the formula (2) are C _n H _{2n + 1} (n = 1 to 6), and R3 is H or C _n H _{2n + 1} (n = 1 to 6).

  Examples of the quaternary ammonium organic cation having a skeleton represented by the formula (1) include imidazolium ions such as dialkylimidazolium and trialkylimidazolium, tetraalkylammonium ions, alkylpyridinium ions, pyrazolium ions, pyrrolidinium ions, And piperidinium ions. In particular, an imidazolium cation having a skeleton represented by the formula (2) is preferable.

  Examples of the tetraalkylammonium ion include, but are not limited to, trimethylethylammonium ion, trimethylethylammonium ion, trimethylpropylammonium ion, trimethylhexylammonium ion, and tetrapentylammonium ion.

  Examples of the alkylpyridium ion include N-methylpyridinium ion, N-ethylpyridinium ion, N-propylpyridinium ion, N-butylpyridinium ion, 1-ethyl-2-methylpyridinium ion, 1-butyl-4-methylpyridinium ion Ions, 1-butyl-2,4 dimethylpyridinium ions and the like, but are not limited thereto.

  In addition, the normal temperature molten salt which has these cations may be used independently, or may be used in mixture of 2 or more types.

  Examples of the imidazolium cation having a skeleton represented by the formula (2) include 1,3-dimethylimidazolium ion, 1-ethyl-3-methylimidazolium ion, and 1-methyl-3-ethyl as dialkylimidazolium ions. Examples include imidazolium ions, 1-methyl-3-butylimidazolium ions, 1-butyl-3-methylimidazolium ions, and the like. Trialkylimidazolium ions include 1,2,3-trimethylimidazolium ions, 1 , 2-dimethyl-3-ethylimidazolium ion, 1,2-dimethyl-3-propylimidazolium ion, 1-butyl-2,3-dimethylimidazolium ion, and the like, but are not limited thereto. Absent.

  In addition, the normal temperature molten salt which has these cations may be used independently, or may mix and use 2 or more types.

5) Exterior material As the exterior material, a metal container having a thickness of 0.5 mm or less or a laminate film container having a thickness of 0.2 mm or less can be used. As the metal container, a metal can made of aluminum, aluminum alloy, iron, stainless steel or the like having a square or cylindrical shape can be used. As the laminate film, it is preferable to use a multilayer film in which a metal foil is coated with a resin film. Polymers such as polypropylene (PP), polyethylene (PE), nylon, polyethylene terephthalate (PET) can be used as the resin. More preferably, a metal container or a laminate film container having a wall thickness of 0.2 mm or less is used.

(Second Embodiment)
In the nonaqueous electrolyte battery according to the second embodiment, the negative electrode containing a negative electrode active material having an average operating potential exceeding 0.4 V with respect to the potential of metallic lithium, and the oxidation-reduction potential (relative to the potential of metallic lithium) is 0. A nonaqueous electrolyte containing a carbonyl compound (hereinafter referred to as a second overcharge inhibitor (reduced overcharge inhibitor)) that is 4 V or higher and lower than the average operating potential of the negative electrode is used. The kind of the carbonyl compound to be used can be one kind or two or more kinds.

  Examples of the negative electrode active material having an average operating potential exceeding 0.4 V with respect to the potential of metallic lithium include the same materials as described in the first embodiment.

  The average operating potential of the negative electrode refers to a value obtained by dividing the charge / discharge electric energy by the charge / discharge electric energy when charging / discharging at the upper and lower limits of the charge / discharge potential of the negative electrode when charging / discharging in the recommended operating voltage range of the battery.

  A more preferable negative electrode active material is a compound whose negative electrode operating potential lower limit is higher than the reduction potential of the reduced overcharge inhibitor (0.43 V to 1.39 V with respect to the metal lithium potential). If the lower limit of the negative electrode operating potential is lower than the reduction potential of the reduced overcharge inhibitor, it may cause a reduction reaction of the reduced overcharge inhibitor during normal charge and discharge, and the charge / discharge performance may be impaired. It is. The lower limit of the operating potential of the negative electrode in this case refers to the lower limit of the charging / discharging potential of the negative electrode when charged and discharged within the recommended operating voltage range of the battery.

  The average operating potential of the negative electrode using lithium titanate and iron sulfide (for example, FeS) as the negative electrode active material is shown in Table 1 below. All are values with respect to metallic lithium potential.

  FIG. 19 shows a potential curve of a negative electrode using spinel type lithium titanate as the negative electrode active material. The horizontal axis in FIG. 19 is the capacity (mAh). The change in potential when the capacity changes in the direction of the right arrow is the change in potential during charging, and the change in potential when the capacity changes in the direction of the left arrow is during discharge. Is the potential change. The vertical axis indicates the negative electrode potential (relative to the metal lithium potential). Since the average operating potential is 1.55 V as shown in FIG. 19 and Table 1 described above, a carbonyl compound having a redox potential of 0.4 V or more and less than 1.55 V can be used. Examples of such a carbonyl compound include the types of carbonyl compounds shown in Table 2.

  Among the above carbonyl compounds, benzophenone, trans-2-butenal, 2-ethoxy-2-cyclohexane-1-one, 1-formylcyclohexene, 2-cyclohexane-1-one, trans-2,2,6,6-tetra Methyl-4-heptone-3-one and 1-acetyl-4-tert-butylcyclohexane are preferred. Since the oxidation-reduction potential of these carbonyl compounds is 1 V or more and 1.4 V or less, which is close to the average operating potential of the lithium titanate negative electrode 1.55 V and close to 1.4 V causing a sudden potential drop, The second overcharge preventing agent functions quickly and can suppress negative electrode deterioration due to a decrease in the negative electrode operating potential. In particular, trans-2-butenal, 2-ethoxy-2-cyclohexane-1-one, 1-formylcyclohexene, and 2-cyclohexane-1-one are more desirable because they hardly cause side reactions with the positive electrode.

  A potential curve of a negative electrode using iron sulfide such as FeS as the negative electrode active material is shown in FIG. The horizontal axis of FIG. 20 is the capacity (mAh). The change in potential when the capacity changes in the direction of the right arrow is the change in potential during charging, and the change in potential when the capacity changes in the direction of the left arrow is during discharge. Is the potential change. The vertical axis indicates the negative electrode potential (relative to the metal lithium potential). Since the average operating potential is 1.75 V as shown in FIG. 20 and Table 1 described above, a carbonyl compound having an oxidation-reduction potential of 0.4 V or more and less than 1.75 V can be used. Examples of such a carbonyl compound include the types of carbonyl compounds shown in Table 2 described above. In particular, 5,5-dimethoxy-3-isobutoxy-2-cyclohexane-1-one and 2-methoxy-2-acetylcyclohexanone are preferable. As shown in FIG. 20, in the charging potential curve of the iron sulfide negative electrode, a sudden potential drop occurs from around 1.4 V at which full charge occurs. Within the potential range causing this sudden potential drop and at some distance from the average operating voltage, 5,5-dimethoxy-3-isobutoxy-2-cyclohexane-1-one and 2-methoxy-2-acetylcyclohexanone Since there is an oxidation-reduction potential, the second overcharge inhibitor does not react even when the negative electrode potential decreases to some extent due to the influence of impedance when charged with a large current in the normal use range, and high efficiency In addition, in the case of overcharging, the second overcharge inhibitor functions quickly, and it is possible to suppress a decrease in the operating potential of the negative electrode up to the potential at which the iron component is liberated.

  FIG. 2 shows the redox potential (0.01 V) of the negative electrode containing carbon, the redox potential (average operating potential; 1.55 V) of the negative electrode containing lithium titanate, and the redox potential (average operating voltage 3) of the positive electrode. .2 to 4.1 V) and the redox potential of the carbonyl compound. The oxidation-reduction potential is any potential with respect to metallic lithium. Since the redox potential of the carbonyl compound is smaller than the average operating potential of the negative electrode, when the negative electrode potential becomes lower than the average operating potential of 1.55 V due to overcharging, a reduction reaction of the carbonyl compound occurs. This reduces the possibility of overcharging by reducing the current that should be spent on charging. Moreover, since the oxidation-reduction potential of the carbonyl compound is 0.4 V or more, lithium deposition and decomposition of the negative electrode active material during the reduction reaction of the carbonyl compound can be suppressed. As a result, it is possible to prevent heat generation by suppressing heat generation during overcharge. The oxidized carbonyl compound is oxidized at the positive electrode and returns to its original state.

  When carbon is used for the negative electrode, the average operating potential of the negative electrode is 0.01 V, whereas the redox potential of the carbonyl compound is 0.4 V or more, so that the reduction reaction of the carbonyl compound occurs in normal times and self-discharge occurs. Arise.

  That is, since the second overcharge inhibitor has a redox potential reversible to a base potential lower than that of the negative electrode, when the battery is overcharged, this material is reduced at the negative electrode, and the material is convected or diffused to the positive electrode. Then, the action of being oxidized and returning to the original state is achieved in the battery, and the possibility of overcharging can be reduced by reducing the current that should be spent for charging.

  Further, the second overcharge inhibitor is a liquid having a small molecular weight and is excellent in solubility in a non-aqueous solvent. In particular, the second overcharge inhibitor is excellent in compatibility with two or more kinds of mixed solvents selected from the group consisting of EC, PC, GBL, DEC, DMC, and MEC. As a result, according to the second overcharge prevention agent, not only can ignition be prevented during overcharge, but also overcharge cycle performance at a low temperature and overcharge cycle performance at a high rate can be improved.

  The amount of the second overcharge inhibitor added is desirably 0.001 mol / L or more and 10 mol / L or less. When the addition amount is less than 0.001 mol / L, a sufficient overcharge preventing effect cannot be expected because the current flowing through the second overcharge preventing agent is small. On the other hand, when the addition amount exceeds 10 mol / L, the vapor pressure of the non-aqueous electrolyte increases, and thus there is a risk that gas will accumulate in the battery when the battery is exposed to high temperatures. More preferably, it is the range of 0.1 mol / L or more and 3 mol / L or less.

  Since the second overcharge inhibitor acts first on the negative electrode during charging, it is desirable to use it when the negative electrode capacity in which the negative electrode potential easily changes is smaller than the positive electrode capacity. The capacitance of each electrode is determined by which potential has changed greatly at the end of charging when each electrode is taken out and charged to the voltage specified by the method of use. In other words, the larger the change, the smaller the capacity. In order to obtain a sufficient effect, it is desirable that the ratio of the positive electrode capacity to the negative electrode capacity (positive electrode / negative electrode) be 1.001 or more and 1.400 or less.

  There is no problem even if both the first overcharge inhibitor and the second overcharge inhibitor are added. In this case, the positive electrode capacity and the negative electrode capacity may be equal, or one of them may be large.

  As an application to the charge / discharge system of the nonaqueous electrolyte battery according to the present embodiment, it can be used as a power source of a control system that drives a drive motor of an electric vehicle.

  The structure of an example of the nonaqueous electrolyte battery according to the embodiment of the present invention will be described with reference to FIGS. In FIG. 3, the cross-sectional schematic diagram of the flat type nonaqueous electrolyte secondary battery concerning embodiment of this invention is shown. FIG. 4 is a partial cross-sectional schematic diagram showing in detail a portion surrounded by a circle indicated by A in FIG.

  As shown in FIG. 3, a flat wound electrode group 6 is accommodated in the exterior member 7. The wound electrode group 6 has a structure in which the positive electrode 3 and the negative electrode 4 are wound in a spiral shape with a separator 5 interposed therebetween. The nonaqueous electrolyte is held in the wound electrode group 6.

  As shown in FIG. 4, the negative electrode 4 is located on the outermost periphery of the wound electrode group 6, and the separator 5, the positive electrode 3, the separator 5, the negative electrode 4, the separator 5, and the positive electrode 3 are arranged on the inner peripheral side of the negative electrode 4. The positive electrode 3 and the negative electrode 4 are alternately stacked with the separator 5 interposed therebetween, such as a separator 5. The negative electrode 4 includes a negative electrode current collector 4a and a negative electrode active material-containing layer 4b supported on the negative electrode current collector 4a. In the portion located on the outermost periphery of the negative electrode 4, the negative electrode active material-containing layer 4b is formed only on one surface of the negative electrode current collector 4a. The positive electrode 3 includes a positive electrode current collector 3a and a positive electrode active material-containing layer 3b supported on the positive electrode current collector 3a.

  As shown in FIG. 3, the strip-like positive electrode terminal 1 is electrically connected to the positive electrode current collector 3 a in the vicinity of the outer peripheral end of the wound electrode group 6. On the other hand, the strip-like negative electrode terminal 2 is electrically connected to the negative electrode current collector 4 a in the vicinity of the outer peripheral end of the wound electrode group 6. The tips of the positive electrode terminal 1 and the negative electrode terminal 2 are drawn out from the same side of the exterior member 7.

  The nonaqueous electrolyte battery according to the embodiment of the present invention is not limited to the configuration shown in FIGS. 3 and 4 described above, and may be configured as shown in FIGS. 5 and 6, for example. FIG. 5 is a partially cutaway perspective view schematically showing another flat type nonaqueous electrolyte secondary battery according to the embodiment of the present invention, and FIG. 6 is an enlarged sectional view of a portion B in FIG.

  As shown in FIG. 5, a laminated electrode group 9 is accommodated in an exterior member 8 made of a laminate film. For example, as shown in FIG. 6, the laminate film includes a resin layer 10, a thermoplastic resin layer 11, and a metal layer 12 disposed between the resin layer 10 and the thermoplastic resin layer 11. The thermoplastic resin layer 11 is located on the inner surface of the exterior member 8. Heat seal portions 8 a, 8 b, and 8 c are formed on one long side and both short sides of the laminate film exterior member 8 by thermal fusion of the thermoplastic resin layer 11. The exterior member 8 is sealed by the heat seal portions 8a, 8b, and 8c.

  The stacked electrode group 9 includes a plurality of positive electrodes 3, a plurality of negative electrodes 4, and a separator 5 disposed between each positive electrode 3 and each negative electrode 4. As shown in FIG. 6, the stacked electrode group 9 has a structure in which the positive electrodes 3 and the negative electrodes 4 are alternately stacked with separators 5 interposed therebetween. Each positive electrode 3 includes a positive electrode current collector 3a and a positive electrode active material-containing layer 3b supported on both surfaces of the positive electrode current collector 3a. Each negative electrode 4 includes a negative electrode current collector 4a and a negative electrode active material-containing layer 4b supported on both surfaces of the negative electrode current collector 4a. One short side of the negative electrode current collector 4 a of the negative electrode 4 protrudes from the positive electrode 3. The negative electrode current collector 4 a protruding from the positive electrode 3 is electrically connected to the strip-shaped negative electrode terminal 2. The tip of the strip-like negative electrode terminal 2 is drawn out through the heat seal portion 8 c of the exterior member 8. Both surfaces of the negative electrode terminal 2 are opposed to the thermoplastic resin layer 11 constituting the heat seal portion 8c. In order to improve the bonding strength between the heat seal portion 8 c and the negative electrode terminal 2, an insulating film 13 is interposed between each surface of the negative electrode terminal 2 and the thermoplastic resin layer 11. Examples of the insulating film 13 include a film formed from a material obtained by adding an acid anhydride to a polyolefin containing at least one of polypropylene and polyethylene.

  Although not shown here, one of the short sides of the positive electrode current collector 3 a of the positive electrode 3 protrudes from the negative electrode 4. The direction in which the positive electrode current collector 3a protrudes is opposite to the direction in which the negative electrode current collector 4a protrudes. The positive electrode current collector 3 a protruding from the negative electrode 4 is electrically connected to the belt-like positive electrode terminal 1. The front end of the strip-like positive electrode terminal 1 is drawn out through the heat seal portion 8 b of the exterior member 8. In order to improve the bonding strength between the heat seal portion 8 b and the positive electrode terminal 1, an insulating film 13 is interposed between the positive electrode terminal 1 and the thermoplastic resin layer 11. The direction in which the positive electrode terminal 1 is pulled out from the exterior member 8 is opposite to the direction in which the negative electrode terminal 2 is pulled out from the exterior member 8.

In order to realize high current performance even when used for a long period of time, the electrode group including the positive electrode and the negative electrode has a laminated structure, and the separator is used by folding into ninety nines as shown in FIG. Is preferred. The strip-shaped separator 5 is folded in ninety-nine. A strip-shaped positive electrode 3 ₁ , a strip-shaped negative electrode 4 ₁ , a strip-shaped positive electrode 3 ₂ , and a strip-shaped negative electrode 4 ₂ are inserted into the part where the separators 5 overlap each other in order from the top. A positive electrode terminal 14 is drawn from the short side of each of the strip-shaped positive electrodes 3 ₁ , 3 ₂ . In this way, the positive electrode 3 and the negative electrode 4 are alternately arranged between the separators 5 folded in ninety-nine, thereby obtaining an electrode group having a laminated structure.

  The non-aqueous electrolyte battery according to the embodiment of the present invention is not limited to using the laminate film container illustrated in FIGS. 3 to 6 described above, and for example, a configuration using a metal container illustrated in FIG. 8. Can be.

  The exterior member includes a container 81 made of aluminum or aluminum alloy and having a bottomed rectangular tube shape, a lid body 82 disposed in an opening of the container 81, and a negative electrode terminal 84 attached to the lid body 82 via an insulating material 83. Are provided. The container 81 also serves as a positive electrode terminal.

  The electrode group 85 is accommodated in the container 81. The electrode group 85 has a structure in which a positive electrode 86 and a negative electrode 87 are wound into a flat shape via a separator 88. The electrode group 85 is formed by, for example, winding a strip in which the positive electrode 86, the separator 88, and the negative electrode 87 are laminated in this order in a spiral shape using a plate-shaped or cylindrical winding core so that the positive electrode 86 is located outside. Then, the obtained wound product is obtained by pressure molding in the radial direction.

  A non-aqueous electrolyte (liquid non-aqueous electrolyte) is held in the electrode group 85. A spacer 90 made of, for example, a synthetic resin having a lead extraction hole 89 near the center is disposed on the electrode group 85 in the container 81.

  An extraction hole 91 for the negative electrode terminal 84 is opened near the center of the lid 82. The liquid injection port 92 is provided at a position away from the extraction hole 91 of the lid 82. The liquid injection port 92 is sealed with a sealing plug 93 after injecting a non-aqueous electrolyte into the container 81. The negative electrode terminal 84 is hermetically sealed in the take-out hole 91 of the lid 82 via an insulating material 83 made of glass or resin.

  A negative electrode lead tab 94 is welded to the lower end surface of the negative electrode terminal 84. The negative electrode lead tab 94 is electrically connected to the negative electrode 87. One end of the positive electrode lead 95 is electrically connected to the positive electrode 86, and the other end is welded to the lower surface of the lid body 82. The insulating paper 96 covers the entire outer surface of the lid 82. The outer tube 97 covers the entire side surface of the container 81, and the upper and lower ends are folded back on the upper and lower surfaces of the battery body.

(Third embodiment)
The battery pack according to the third embodiment has a plurality of nonaqueous electrolyte batteries according to the first and second embodiments as unit cells. Each unit cell is electrically arranged in series or in parallel to form an assembled battery.

  As described above, the unit cells according to the first and second embodiments are excellent in overdischarge cycle performance. By configuring an assembled battery from these single cells, it is possible to match the state of charge of the unit battery that has shifted due to usage conditions such as temperature by charging it for a certain period of time at a voltage equivalent to full charge. It becomes possible to have a long time. The flat type nonaqueous electrolyte battery shown in FIG. 3, FIG. 5, or FIG. 8 can be used as the unit cell.

  The unit cell 21 in the battery pack of FIG. 9 is composed of a flat type nonaqueous electrolyte battery shown in FIG. The plurality of unit cells 21 are stacked in the battery thickness direction, and the side surfaces from which the positive electrode terminal 1 and the negative electrode terminal 2 protrude are opposed to the printed wiring board 24. As shown in FIG. 10, the unit cells 21 are connected in series to form an assembled battery 22. The assembled battery 22 is integrated with an adhesive tape 23 as shown in FIG.

  A printed wiring board 24 is disposed on the side surface from which the positive electrode terminal 1 and the negative electrode terminal 2 protrude. As shown in FIG. 10, the printed wiring board 24 is mounted with a thermistor 25, a protection circuit 26, and a terminal 27 for energizing external devices.

  As shown in FIGS. 9 and 10, the positive electrode side wiring 28 of the assembled battery 22 is electrically connected to the positive electrode side connector 29 of the protection circuit 26 of the printed wiring board 24. The negative electrode side wiring 30 of the assembled battery 22 is electrically connected to the negative electrode side connector 31 of the protection circuit 26 of the printed wiring board 24.

  The thermistor 25 is for detecting the temperature of the unit cell 21, and the detection signal is transmitted to the protection circuit 26. The protection circuit 26 can cut off the plus side wiring 31a and the minus side wiring 31b between the protection circuit and a terminal for energization to an external device under a predetermined condition. The predetermined condition is, for example, when the detected temperature of the thermistor becomes equal to or higher than a predetermined temperature, or when overcharge, overdischarge, overcurrent, or the like of the unit cell 21 is detected. This detection method is performed for each individual cell 21 or the entire cell 21. When detecting each single cell 21, the battery voltage may be detected, or the positive electrode potential or the negative electrode potential may be detected. In the latter case, a lithium electrode used as a reference electrode is inserted into each unit cell 21. In the case of FIG. 10, a voltage detection wiring 32 is connected to each single cell 21, and a detection signal is transmitted to the protection circuit 26 through the wiring 32.

  In the assembled battery 22, a protective sheet 33 made of rubber or resin is disposed on three side surfaces other than the side surface from which the positive electrode terminal 1 and the negative electrode terminal 2 protrude. Between the side surface from which the positive electrode terminal 1 and the negative electrode terminal 2 protrude and the printed wiring board 24, a block-shaped protection block 34 made of rubber or resin is disposed.

  The assembled battery 22 is stored in a storage container 35 together with the protective sheets 33, the protective blocks 34, and the printed wiring board 24. That is, the protective sheet 33 is disposed on each of the inner side surface in the long side direction and the inner side surface in the short side direction of the storage container 35, and the printed wiring board 24 is disposed on the inner side surface on the opposite side in the short side direction. The assembled battery 22 is located in a space surrounded by the protective sheet 33 and the printed wiring board 24. A lid 36 is attached to the upper surface of the storage container 35.

  In addition, instead of the adhesive tape 23, a heat shrink tape may be used for fixing the assembled battery 22. In this case, protective sheets are arranged on both side surfaces of the assembled battery, the heat shrinkable tube is circulated, and then the heat shrinkable tube is thermally contracted to bind the assembled battery.

  Although the single cells 21 shown in FIGS. 9 and 10 are connected in series, they may be connected in parallel to increase the battery capacity. Of course, the assembled battery packs can be connected in series and in parallel.

  Moreover, the aspect of a battery pack is changed suitably by a use.

  As a use of the battery pack of the third embodiment, a battery pack in which cycle performance at a large current is desired is preferable. Specific examples include a power source for a digital camera, a vehicle for a two- to four-wheel hybrid electric vehicle, a two- to four-wheel electric vehicle, an assist bicycle, and the like. In particular, the vehicle-mounted one is suitable.

(Fourth embodiment)
The automobile according to the fourth embodiment includes the battery pack according to the third embodiment. Generally, a large current of about 10 C or more flows through a battery pack for vehicle use. When a large current flows, a large difference occurs in the temperature and impedance between the single cells, so that some of the single cells tend to fall into an overdischarged state. However, since the unit cells of the first and second embodiments are excellent in overdischarge cycle performance, the battery pack of the third embodiment is excellent in cycle performance due to this. Therefore, the automobile according to the fourth embodiment is excellent in maintaining the characteristics of the drive source. Examples of the vehicle herein include a two-wheel to four-wheel hybrid electric vehicle, a two-wheel to four-wheel electric vehicle, and an assist bicycle.

  FIGS. 11 to 13 show a hybrid type automobile using a traveling power source by combining an internal combustion engine and a battery-driven electric motor. The driving force of an automobile requires a power source with a wide range of rotation speeds and torques depending on the running conditions. In general, an internal combustion engine has a limited torque and rotational speed that show ideal energy efficiency. Therefore, the energy efficiency decreases under other operating conditions. Hybrid type automobiles generate power by operating an internal combustion engine under optimum conditions, and by driving wheels with a high-efficiency electric motor, or by driving the internal combustion engine and the electric motor together. The overall energy efficiency can be improved. Further, by regenerating the kinetic energy of the vehicle as electric power during deceleration, the travel distance per unit fuel can be dramatically increased compared to a normal internal combustion engine vehicle.

  Hybrid vehicles can be broadly classified into three types depending on the combination of the internal combustion engine and the electric motor.

  FIG. 11 shows a hybrid vehicle 50 generally called a series hybrid vehicle. All the power of the internal combustion engine 51 is once converted into electric power by the generator 52, and this electric power is stored in the battery pack 54 through the inverter 53. As the battery pack 54, the battery pack according to the second embodiment of the present invention is used. The electric power of the battery pack 54 is supplied to the electric motor 55 through the inverter 53, and the wheels 56 are driven by the electric motor 55. It is a system in which a generator is combined with an electric vehicle. The internal combustion engine can be operated under highly efficient conditions and can also regenerate power. On the other hand, since driving of the wheels is performed only by the electric motor, a high-output electric motor is required. Also, a battery pack having a relatively large capacity is required. The rated capacity of the battery pack is preferably in the range of 5 to 50 Ah. A more preferable range is 10 to 20 Ah. Here, the rated capacity means a capacity when discharged at a 0.2 C rate.

  FIG. 12 shows a hybrid vehicle 57 called a parallel hybrid vehicle. Reference numeral 58 indicates an electric motor that also serves as a generator. The internal combustion engine 51 mainly drives the wheels 56, and in some cases, a part of the power is converted into electric power by the generator 58, and the battery pack 54 is charged with the electric power. The driving force is assisted by the electric motor 58 at the time of start and acceleration where the load becomes heavy. This is a system based on a normal automobile, which reduces the load fluctuation of the internal combustion engine 51 to improve efficiency and also performs power regeneration. Since the driving of the wheels 56 is mainly performed by the internal combustion engine 51, the output of the electric motor 58 can be arbitrarily determined depending on the necessary auxiliary ratio. The system can also be configured using a relatively small electric motor 58 and battery pack 54. The rated capacity of the battery pack can be in the range of 1-20 Ah. A more preferable range is 3 to 10 Ah.

  FIG. 13 shows a hybrid vehicle 59 called a series / parallel hybrid vehicle. This is a combination of both series and parallel. The power split mechanism 60 splits the output of the internal combustion engine 51 into power generation and wheel drive. The engine load can be controlled more finely than the parallel system, and energy efficiency can be improved.

  The rated capacity of the battery pack is desirably in the range of 1 to 20 Ah. A more preferable range is 3 to 10 Ah.

  The nominal voltage of the battery pack mounted on the hybrid vehicle as shown in FIGS. 11 to 13 is preferably in the range of 200 to 600V.

  The battery pack 54 is preferably arranged in a place that is generally less susceptible to changes in the outside air temperature and is less susceptible to impact during a collision or the like. For example, in a sedan type automobile as shown in FIG. 14, it can be arranged in the trunk room 62 behind the rear seat 61. Further, it can be placed under or behind the seat 61. When the battery weight is large, it is preferable to arrange the battery under the seat or under the floor in order to lower the center of gravity of the entire vehicle.

  An electric vehicle (EV) travels with energy stored in a battery pack that is charged by supplying power from outside the vehicle. Therefore, the electric vehicle can use electric energy generated with high efficiency using other power generation facilities. Further, since the kinetic energy of the automobile can be regenerated as electric power during deceleration, the energy efficiency during traveling can be increased. Electric vehicles are clean vehicles because they emit no carbon dioxide or other exhaust gases. On the other hand, since all the power during running is an electric motor, a high output electric motor is required. In general, since it is necessary to store all energy necessary for one driving in a battery pack by one charge, a battery having a very large capacity is required. The rated capacity of the battery pack is desirably in the range of 100 to 500 Ah. A more preferable range is 200 to 400 Ah.

  Further, since the ratio of the battery weight to the weight of the vehicle is large, the battery pack is preferably disposed at a low position such as being spread under the floor and at a position not far away from the center of gravity of the vehicle. In order to charge a large amount of power corresponding to one run in a short time, a large-capacity charger and a charging cable are required. For this reason, it is desirable that the electric vehicle includes a charging connector for connecting them. As the charging connector, a normal connector using electrical contacts can be used, but a non-contact charging connector using electromagnetic coupling may be used.

  FIG. 15 shows an example of the hybrid bike 63. Also in the case of a two-wheeled vehicle, a hybrid bike with high energy efficiency including the internal combustion engine 64, the electric motor 65, and the battery pack 54 can be configured as in the case of a hybrid vehicle. The internal combustion engine 64 mainly drives the wheels 66, and the battery pack 54 is charged with a part of the power in some cases. The driving force is assisted by the electric motor 65 when starting or accelerating when the load becomes heavy. Since the wheels 66 are driven mainly by the internal combustion engine 64, the output of the electric motor 65 can be arbitrarily determined depending on the required auxiliary ratio. The system can also be configured using a relatively small electric motor 65 and battery pack 54. The rated capacity of the battery pack can be in the range of 1-20 Ah. A more preferable range is 3 to 10 Ah.

  FIG. 16 shows an example of the electric motorcycle 67. The electric motorcycle 67 travels with the energy stored in the battery pack 54 that is charged by supplying electric power from the outside. Since all the driving power is the electric motor 65, a high-output electric motor 65 is required. In general, it is necessary to store all the energy required for one run in a battery pack by a single charge, so a battery having a relatively large capacity is required. The rated capacity of the battery pack is desirably in the range of 10 to 50 Ah. A more preferable range is 15 to 30 Ah.

(Fifth embodiment)
17 and 18 show an example of a rechargeable vacuum cleaner according to the fifth embodiment. The rechargeable vacuum cleaner includes an operation unit 75 that selects an operation mode, an electric blower 74 that includes a fan motor that generates a suction force for collecting dust, and a control circuit 73. As a power source for driving them, the battery pack 72 according to the second embodiment is accommodated in a housing 70 of the vacuum cleaner. When the battery pack is accommodated in such a portable device, it is desirable to fix the battery pack via a cushioning material in order to avoid the influence of vibration. A well-known technique can be applied to maintain the battery pack at an appropriate temperature. A part or all of the charger function of the charger 71 also serving as a pedestal may be accommodated in the housing 70.

  Although the power consumption of the rechargeable vacuum cleaner is large, it is desirable that the rated capacity of the battery pack be in the range of 2 to 10 Ah in consideration of portability and operation time. A more preferable range is 2 to 4 Ah. The nominal voltage of the battery pack is preferably in the range of 40-80V.

  Generally, a battery pack for a rechargeable vacuum cleaner uses a large current of about 3C to 5C and is used from a fully charged state to a fully discharged state. When a large current flows, a large difference occurs in the temperature and impedance between the single cells, and an overdischarge state tends to occur in a complete discharge state. However, since the unit cells of the first and second embodiments are excellent in overdischarge cycle performance, the battery pack of the third embodiment is excellent in cycle performance due to this. Therefore, the rechargeable vacuum cleaner according to the fifth embodiment is resistant to repeated charging and discharging.

[Example]
Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following examples as long as the gist of the invention is not exceeded.

(Example 1)
A battery having the structure shown in FIG. 3 was produced. In the following examples and comparative examples, the structure of the battery itself is the same as that shown in FIG.

<Preparation of positive electrode>
First, 90% by weight of lithium cobalt oxide (LiCoO ₂ ) powder, 3% by weight of acetylene black, 3% by weight of graphite and 4% by weight of polyvinylidene fluoride (PVdF) are added to N-methylpyrrolidone (NMP) as a positive electrode active material. The slurry was mixed to form a slurry, and this slurry was applied to both sides of a current collector made of 15 μm aluminum foil, then dried and pressed, whereby the basis weight of the positive electrode layer was 50 g / m ² and the electrode density was 3.0 g. A positive electrode of / cm ³ was produced.

<Production of negative electrode>
Weight of spinel type lithium titanate (Li ₄ Ti ₅ O ₁₂ ) as a negative electrode active material, coke having an average particle size of 1.12 μm and a specific surface area of 82 m ² / g as a conductive material, and polyvinylidene fluoride (PVdF) A slurry was prepared by adding to the N-methylpyrrolidone (NMP) solution and mixing at a ratio of 90: 5: 5. The obtained slurry was applied to an aluminum foil having a thickness of 15 μm, dried and pressed to prepare a negative electrode having a negative electrode layer weight per unit area of 50 g / m ² .

<Production of electrode group>
After laminating a positive electrode, a separator made of a polyethylene porous film having a thickness of 25 μm, a negative electrode, and a separator in this order, they were wound in a spiral shape. This was heated and pressed at 90 ° C. to produce a flat electrode group having a width of 30 mm and a thickness of 3.0 mm. The obtained electrode group is housed in a pack made of a laminate film having a thickness of 0.1 mm, which is composed of an aluminum foil having a thickness of 40 μm and a polypropylene layer formed on both surfaces of the aluminum foil. Vacuum drying was performed for 24 hours.

<Preparation of liquid nonaqueous electrolyte>
1.5 mol / L of lithium tetrafluoroborate (LiBF ₄ ) as an electrolyte is dissolved in a mixed solvent (volume ratio 25:75) of ethylene carbonate (EC) and γ-butyrolactone (GBL) as an overcharge inhibitor. A liquid nonaqueous electrolyte (nonaqueous electrolyte solution) was prepared by dissolving 1.0 mol / L of cerium tetrafluoroborate (Ce (BF ₄ ) ₃ ) and 1.0 mol / L of trans-2-butenal.

  After injecting the liquid non-aqueous electrolyte into the laminated film pack containing the electrode group, the pack is completely sealed by heat sealing, and has the structure shown in FIG. A nonaqueous electrolyte secondary battery having a size of 3.2 mm and a height of 65 mm was produced.

(Examples 2 to 7)
A non-aqueous electrolyte secondary battery having the same configuration as described in Example 1 except that the type of the negative electrode active material, the type and concentration of the overcharge inhibitor are changed as shown in Tables 3 and 4 below. Produced.

(Examples 8 to 16)
The nonaqueous electrolyte 2 having the same configuration as described in Example 1 except that the type of the negative electrode active material, the type and concentration of the overcharge inhibitor, and the capacity ratio are changed as shown in Tables 3 and 4 below. A secondary battery was produced.

(Comparative Example 1)
A nonaqueous electrolyte secondary battery having the same configuration as described in Example 1 was prepared except that no overcharge inhibitor was added.

(Comparative Examples 2 and 3)
A nonaqueous electrolyte secondary battery having the same configuration as that described in Example 1 was prepared except that the type and concentration of the overcharge inhibitor were changed as shown in Table 3 below.

  An overcharge test of 12 V, 3 C, and 4 hours was performed, and the heat generation and ignition status at that time were measured and recorded. In addition, battery swelling was observed when stored at 85 ° C. for 24 hours in a fully charged state. The swell tolerance of this storage test is up to 10% swell. These test results are shown in Table 4.

  Moreover, the overcharge cycle test of the battery was done. As the overcharge test conditions, charging was performed at a 1C rate, a constant current and a constant voltage of 4.4 V for 4 hours, and then a test was performed 500 times at a 1C rate to discharge to a specified voltage. Table 1 shows the maintenance rate by taking the ratio between the 1C rate from the fully charged state before the overcharge test and the 1C rate discharge capacity at the end of the overcharge cycle.

  As is clear from Tables 3 and 4, the batteries of Examples 1 to 16, 16-1, and 16-2 using the first overcharge inhibitor or the second overcharge inhibitor ignited in the overcharge test. And does not swell in the high temperature storage test, and there is little deterioration of the discharge capacity during the overcharge cycle.

On the other hand, in the battery of Comparative Example 1 in which no overcharge inhibitor was used, it ignited in the overcharge test, expanded by 200% in the high temperature storage test, and further, the discharge capacity during the overcharge cycle was greatly deteriorated. . Further, in Comparative Examples 2 and ₃ using Ce (NH ₄ ) ₂ (NO ₃ ) ₅ or Ce (NO ₃ ) ₃ described in Patent Document 1 described above, gas is generated during the overcharge cycle, and 200 % And the discharge capacity during the overcharge cycle was greatly deteriorated.

  In addition, from the results of Examples 2 to 7, the concentration of the first overcharge inhibitor is 0.001 mol by setting the concentration of the first overcharge inhibitor to 0.1 mol / L or more and 3 mol / L or less. It can be seen that the maximum temperature of the overcharge test is lower and the capacity retention rate of the overcharge cycle is higher than in Examples 4 and 5 of / L or 4 mol / L.

  From the comparison of Examples 8 to 14, by setting the concentration of the second overcharge inhibitor to 0.1 mol / L or more and 3 mol / L or less, the concentration of the second overcharge inhibitor is 0.001 mol / L. The capacity retention rate of the overcharge cycle is higher than that of Example 12, and the swelling during high temperature storage is reduced as compared with Example 11 in which the concentration of the second overcharge inhibitor is 10 mol / L. Recognize.

  As shown in the results of Examples 15, 16, 16-1, and 16-2, even when iron sulfide or ramsdellite type lithium titanate was used as the negative electrode active material, it did not ignite in the overcharge test and was stored at high temperature. It does not swell in the test, and the deterioration of the discharge capacity during the overcharge cycle is reduced.

  Further, as shown in Example 1, when the first and second overcharge inhibitors are used in combination, the discharge capacity retention rate during the overcharge cycle is higher than that of Examples 2-16, 16-1, 16-2. It became high.

(Examples 17 to 29 and Comparative Examples 4 and 5)
Except for changing the type of the negative electrode active material, the composition of the non-aqueous solvent, the type and concentration of the overcharge inhibitor, and the capacity ratio as shown in Tables 5 and 6 below, the same as described in Example 1 A non-aqueous electrolyte secondary battery having the configuration was produced. In addition, the composition of the non-aqueous solvent was set to the composition mixed by the volume ratio of 1: 1, when the kind of solvent to be used is two kinds. When there were three types of solvent used, a solvent mixed at a volume ratio of 1: 1: 1 was used.

  A high rate overcharge cycle test of the obtained battery was performed under the conditions described below. After performing constant-current constant-voltage charge up to 4 V at 20 C current for 3 hours, 50 charge / discharge cycles were performed to discharge to 1.5 V at 20 C. Based on the discharge capacity when discharged at a 20C rate from the fully charged state before the overcharge test, the capacity retention rate of the discharge capacity at the 50th cycle of the high-rate overcharge cycle was calculated, and the results are shown in Table 6 below.

  Further, a high rate overcharge cycle test at a low temperature was performed under the conditions described below. After performing constant current and constant voltage charging to 4V at 5C current at −20 ° C. for 3 hours, 50 charge / discharge cycles to discharge to 1.5V at 5C were performed. Based on the discharge capacity when discharged at a 5C rate from the fully charged state before the overcharge test, the capacity retention rate of the discharge capacity at the 50th cycle of the low temperature overcharge cycle was calculated, and the results are shown in Table 6 below.

  As shown in Tables 5 and 6, when lithium titanate is used as the negative electrode active material, benzophenone, trans-2-butenal, 2-ethoxy-2-cyclohexane-1-one, Examples 17-24 using formylcyclohexene, 2-cyclohexane-1-one, trans-2,2,6,6-tetramethyl-4-heptone-3-one or 1-acetyl-4-tert-butylcyclohexane Compared to Examples 25 and 26 using 5,5-dimethoxy-3-isobutoxy-2-cyclohexane-1-one or 2-methoxy-2-acetylcyclohexanone, and high rate overcharge cycle performance and low temperature overcharge cycle It turns out that it is excellent in performance. Also, in Examples 17 to 22 using benzophenone, trans-2-butenal, 2-ethoxy-2-cyclohexane-1-one, 1-formylcyclohexene or 2-cyclohexane-1-one as the second overcharge inhibitor In particular, excellent high rate overcharge cycle performance and low temperature overcharge cycle performance were obtained.

  From the results of Examples 28 and 29, when iron sulfide is used as the negative electrode active material, 5,5-dimethoxy-3-isobutoxy-2-cyclohexane-1-one or 2- It can be seen that when methoxy-2-acetylcyclohexanone is used, a high capacity retention ratio can be obtained in both the high rate overcharge cycle and the low temperature overcharge cycle.

  On the other hand, Comparative Example 4 is an example in which 0.22 M of the methoxybenzene described in Patent Document 2 described above was dissolved in a non-aqueous solvent composed of EC and GBL. As shown in the result of Comparative Example 4, with the overcharge inhibitor described in Patent Document 2 described above, the capacity deterioration becomes large in both the high rate overcharge cycle and the low temperature overcharge cycle. Since methoxybenzenes have low solubility in a non-aqueous solvent composed of EC and GBL, the concentration in the non-aqueous solvent could not be further increased even when the addition amount was increased.

  A method for measuring the working potential of the positive electrode in the above embodiment will be described below.

  The measurement of the working potential of the positive electrode was performed by the method described below.

The positive electrode was cut into a size of 2 cm × 2 cm, and used as a working electrode. The working electrode and a counter electrode made of a 2.2 cm × 2.2 cm lithium metal foil were opposed to each other through a glass filter (separator), and lithium metal was inserted as a reference electrode so as not to touch the working electrode and the counter electrode. These electrodes are placed in a three-electrode glass cell, and each of the working electrode, counter electrode, and reference electrode is connected to the terminal of the glass cell, and an electrolyte solution (in a solvent in which ethylene carbonate and γ-butyrolactone are mixed at a volume ratio of 1: 2). 25 mL of an electrolytic solution in which 1.5 M / L lithium tetrafluoroborate (LiBF ₄ ) was dissolved was poured, the separator and the electrode were sufficiently impregnated with the electrolytic solution, and the glass container was sealed. The produced glass cell was arrange | positioned in a 25 degreeC thermostat. First, charging is performed up to 4.4 V at a current density of 0.1 mA / cm ² , and then discharging is performed up to 2 V at the same current density. did.

  The measurement of the working potential of the negative electrode was performed by the method described below.

The negative electrode was cut into a size of 2 cm × 2 cm to obtain a working electrode. The working electrode and a counter electrode made of a 2.2 cm × 2.2 cm lithium metal foil were opposed to each other through a glass filter (separator), and lithium metal was inserted as a reference electrode so as not to touch the working electrode and the counter electrode. These electrodes are placed in a three-electrode glass cell, the working electrode, the counter electrode, and the reference electrode are connected to the terminals of the glass cell, and the electrolyte solution (in a solvent in which ethylene carbonate and γ-butyrolactone are mixed at a volume ratio of 1: 2). 25 mL of an electrolytic solution in which 1.5 M / L lithium tetrafluoroborate (LiBF ₄ ) was dissolved was poured, the separator and the electrode were sufficiently impregnated with the electrolytic solution, and the glass container was sealed. The produced glass cell is placed in a constant temperature bath at 25 ° C., and the value obtained by dividing the amount of discharge power by the amount of discharge electricity when charged to 0.5 V at a current density of 0.1 mA / cm ² is the average operating potential. It was.

  Further, in order to obtain the capacity ratio between the positive electrode capacity and the negative electrode capacity, the positive electrode capacity and the negative electrode capacity were measured by the method described below.

  The capacity of the positive electrode was defined as follows.

The positive electrode was cut into a size of 2 cm × 2 cm, and used as a working electrode. The working electrode and a counter electrode made of a 2.2 cm × 2.2 cm lithium metal foil were opposed to each other through a glass filter (separator), and lithium metal was inserted as a reference electrode so as not to touch the working electrode and the counter electrode. These electrodes are placed in a three-electrode glass cell, and each of the working electrode, the counter electrode, and the reference electrode is connected to the terminal of the glass cell, and the electrolyte solution (the composition of the electrolyte solution is ethylene carbonate and γ-butyrolactone in a volume ratio of 1: 2). Pour 25 mL of an electrolytic solution in which 1.5 M / L lithium tetrafluoroborate (LiBF ₄ ) was dissolved in the mixed solvent, make the separator and electrode sufficiently impregnated with the electrolyte, and seal the glass container did. The produced glass cell is placed in a thermostatic bath at 25 ° C., charged at 4.4 V (reference electrode) at a current density of 0.1 mA / cm ² , and then 0.1 mA / 2.5 to 2.5 V with respect to the reference electrode. and discharged at a current density of cm ^2, further measures the charge capacity at the time of charging at a current density of 0.1 mA / cm ² at 4.4 V (vs. reference electrode), and this value and the capacity of the positive electrode.

The capacity of the negative electrode was prepared by exchanging the positive electrode and the negative electrode for a glass cell having the same configuration as that measured for the capacity of the positive electrode, and the prepared glass cell was placed in a thermostatic bath at 25 ° C., and 0.1 mA / cm ^2. Is charged at a current density of 1.4 V (with respect to the reference electrode), then discharged to ² V with respect to the reference electrode at a current density of 0.1 mA / cm ² , and further 1.4 V at a current density of 0.1 mA / cm ^2. The charge capacity at the time of charging with (counter reference electrode) was measured, and this value was defined as the capacity of the negative electrode.

  When iron sulfide was used as the negative electrode active material, the negative electrode capacity was measured in the same manner as described above except that the negative electrode average operating potential was 1.75V.

  Further, when ramsdellite type lithium titanate was used as the negative electrode active material, the negative electrode capacity was measured in the same manner as described above except that the negative electrode average operating potential was set to 1.5V.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

The characteristic view which shows the relationship between the oxidation-reduction potential of a positive electrode and a negative electrode, and the oxidation-reduction potential of a 1st overcharge inhibitor. The characteristic view which shows the relationship between the oxidation-reduction potential of a positive electrode and a negative electrode, and the oxidation-reduction potential of a 2nd overcharge inhibitor. The cross-sectional schematic diagram of the flat type nonaqueous electrolyte secondary battery concerning 1st, 2nd embodiment. FIG. 4 is a partial cross-sectional schematic diagram showing in detail a portion surrounded by a circle shown by A in FIG. 3. The partial notch perspective view which shows another nonaqueous electrolyte battery concerning 1st, 2nd embodiment. FIG. 6 is a partial cross-sectional schematic diagram showing in detail a portion surrounded by a circle shown by B in FIG. 5. The perspective view which shows typically the electrode group of the laminated structure used with the nonaqueous electrolyte battery concerning 1st, 2nd embodiment. The partial notch perspective view which shows the square nonaqueous electrolyte battery concerning 1st, 2nd embodiment. The disassembled perspective view of the battery pack which concerns on 3rd Embodiment. The block diagram which shows the electric circuit of the battery pack of FIG. The schematic diagram which shows the series hybrid vehicle which concerns on 4th Embodiment. The schematic diagram which shows the parallel hybrid vehicle which concerns on 4th Embodiment. The schematic diagram which shows the series parallel hybrid vehicle which concerns on 4th Embodiment. The schematic diagram which shows the motor vehicle which concerns on 4th Embodiment. The schematic diagram which shows the hybrid motorcycle which concerns on 4th Embodiment. The schematic diagram which shows the electric motorcycle which concerns on 4th Embodiment. The schematic diagram which shows the rechargeable vacuum cleaner which concerns on 5th Embodiment. The block diagram of the rechargeable vacuum cleaner of FIG. The characteristic view which shows the electric potential curve of the negative electrode which used spinel type lithium titanate for the negative electrode active material. The characteristic view which shows the electric potential curve of the negative electrode which used iron sulfide like FeS for a negative electrode active material.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1,14 ... Positive electrode terminal, 2 ... Negative electrode terminal, 3,86 ... Positive electrode, 3a ... Positive electrode collector, 3b ... Positive electrode active material containing layer, 4,87 ... Negative electrode, 4a ... Negative electrode collector, 4b ... Negative electrode active Substance-containing layer, 5, 88 ... separator, 6, 9, 85 ... electrode group, 7, 8 ... exterior member, 8a-8c ... heat seal part, 10 ... resin layer, 11 ... thermoplastic resin layer, 12 ... metal layer , 13 ... Insulating film, 21 ... Single cell, 22 ... Battery pack, 23 ... Adhesive tape, 24 ... Printed circuit board, 25 ... Thermistor, 26 ... Protection circuit, 27 ... Terminal for energization, 28 ... Positive electrode side wiring, 29 ... Positive side connector, 30 ... negative side wiring, 31 ... negative side connector, 31a, 31b, 32 ... wiring, 33 ... protective block, 35 ... storage container, 36 ... lid, 50, 57, 59 ... hybrid car, 51, 64 ... internal combustion engine, 52 ... generator, 53 ... 54, battery pack, 55, 65 ... electric motor, 56, 66 ... wheel, 58 ... electric motor that also serves as a generator, 60 ... power split mechanism, 61 ... rear seat, 62 ... trunk room, 63 ... hybrid bike, 67 ... Electric motorcycle, 70 ... Case, 71 ... Charger that also serves as a stand, 72 ... Battery pack, 73 ... Control circuit, 74 ... Electric blower, 75 ... Operating unit, 81 ... Container, 82 ... Cover, 83 ... Insulating material, 84 ... negative electrode terminal, 90 ... spacer, 94 ... negative electrode lead tab, 95 ... positive electrode lead, 96 ... insulating paper, 97 ... outer tube.

Claims (13)

A positive electrode;
A negative electrode containing a negative electrode active material having an average operating potential of 0.6 V or more with respect to the potential of metallic lithium;
Cerium ions, PF ₆ ⁻ , BF ₄ ⁻ , ClO ₄ ⁻ , CF ₃ SO ₃ ⁻ , N (CF ₃ SO ₂ ) ₂ ⁻ , N (C ₂ F ₅ SO ₂ ) ⁻ and (N (CF ₃ SC ( _{C 2 F 5 SO 2) 3} ) - non-aqueous electrolyte battery characterized by comprising a non-aqueous electrolyte containing an anion of at least one selected from the group consisting of.   The nonaqueous electrolyte battery according to claim 1, wherein a capacity of the negative electrode is larger than a capacity of the positive electrode.   The negative electrode active material is composed of at least one selected from the group consisting of iron sulfide, iron oxide, titanium oxide, lithium titanate, nickel oxide, cobalt oxide, tungsten oxide, molybdenum oxide, and titanium sulfide. The nonaqueous electrolyte battery according to claim 1 or 2.   The non-aqueous electrolyte battery according to claim 1, wherein the positive electrode includes a positive electrode active material having an average operating potential lower than an oxidation potential of the cerium ion.   The positive electrode includes at least one selected from the group consisting of lithium cobaltate, a part of the cobalt component of the lithium cobaltate, other transition elements, Al, Sn, B, F, Mg, Si, S, and P. An element-substituted oxide, lithium nickelate, and at least part of the nickel component of the lithium nickelate selected from the group consisting of other transition elements, Al, Sn, B, F, Mg, Si, S, and P Oxide substituted with one kind of element, lithium manganate, a part of the manganese component of the lithium manganate is selected from the group consisting of other transition elements, Al, Sn, B, F, Mg, Si, S and P And at least one element substituted with an oxide, lithium iron phosphate, and a part of the iron component of the lithium iron phosphate with other transition elements, Al, Sn, B, F, Mg, Si, S and 5. The non-active material according to claim 1, comprising at least one positive electrode active material selected from the group consisting of oxides substituted with at least one element selected from the group consisting of: Water electrolyte battery. A positive electrode;
A negative electrode comprising a negative electrode active material having an average operating potential exceeding 0.4 V with respect to the potential of metallic lithium;
A nonaqueous electrolyte battery comprising a nonaqueous electrolyte containing a carbonyl compound having a redox potential (relative to the lithium metal potential) of 0.4 V or more and less than the average operating potential of the negative electrode.   The negative electrode active material is lithium titanate, and the carbonyl compound is benzophenone, trans-2-butenal, 2-ethoxy-2-cyclohexane-1-one, 1-formylcyclohexene, 2-cyclohexane-1-one, trans-2. The at least one selected from the group consisting of 1,2,6,6-tetramethyl-4-heptone-3-one and 1-acetyl-4-tertiary-butylcyclohexane Non-aqueous electrolyte battery.   The negative electrode active material is iron sulfide, and the carbonyl compound is 5,5-dimethoxy-3-isobutoxy-2-cyclohexane-1-one and / or 2-methoxy-2-acetylcyclohexanone. 6. The nonaqueous electrolyte battery according to 6. A positive electrode;
A negative electrode comprising lithium titanate or iron sulfide;
Trans-2-butenal, 2-cyclohexane-1-one, 2-ethoxy-2-cyclohexane-1-one, 1-formylcyclohexene, trans-2,2,6,6-tetramethyl-4-heptone-3- At least one selected from the group consisting of ON, 2-methoxy-2-acetylcyclohexanone, benzophenone, 5,5-dimethoxy-3-isobutoxy-2-cyclohexane-1-one and 1-acetyl-4-tert-butylcyclohexane A non-aqueous electrolyte battery comprising a non-aqueous electrolyte containing a kind of carbonyl compound.   The nonaqueous electrolyte battery according to claim 6, wherein the capacity of the positive electrode is larger than the capacity of the negative electrode. The non-aqueous electrolyte includes cerium ions, PF ₆ ⁻ , BF ₄ ⁻ , ClO ₄ ⁻ , CF ₃ SO ₃ ⁻ , N (CF ₃ SO ₂ ) ₂ ⁻ , N (C ₂ F ₅ SO ₂ ) ⁻ and ( 10. The nonaqueous electrolyte battery according to claim 6, further comprising at least one anion selected from the group consisting of N (CF ₃ SC (C ₂ F ₅ SO ₂ ) ₃ ) ^−. .   A battery pack comprising the nonaqueous electrolyte battery according to claim 1.   An automobile comprising the nonaqueous electrolyte battery according to claim 1.

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