JP6184588B2 - Nonaqueous electrolyte battery and battery pack - Google Patents

Description

  Embodiments described herein relate generally to a nonaqueous electrolyte battery and a battery pack.

Non-aqueous electrolyte batteries using lithium metal, lithium alloys, lithium compounds, or carbonaceous materials as negative electrodes are expected as high energy density batteries and are actively researched and developed. Up to now, a positive electrode containing LiCoO ₂ , LiMn ₂ O ₄ , LiNi _1/3 Co _1/3 Mn _1/3 O ₂ or LiFePO ₄ as an active material, and a negative electrode containing a carbonaceous material that occludes and releases lithium are provided. Such lithium ion batteries have been widely put into practical use. In the negative electrode, metal oxides or alloys that replace carbonaceous materials have been studied. In particular, in the case of high energy, high output type large-sized batteries such as those for stationary use and automobiles, the negative electrode components are chemically and electrochemically because of the cycle performance under high temperature environment, safety, and long-term reliability of high output. Materials with excellent stability, strength and corrosion resistance are required. Furthermore, high input / output performance and long life performance in a low temperature environment such as a cold district are required.

  Therefore, in recent years, from the viewpoint of thermal stability and safety of non-aqueous electrolytes, development of non-volatile ionic liquids, non-flammable electrolytes, and flame retardant electrolytes has been promoted, but high-temperature cycle performance, discharge rate performance And lowering of low temperature performance is a problem.

JP-A-2005-123183 Japanese Patent Laid-Open No. 2005-142047 JP 2005-317512 A JP 2012-182114 A JP 2014-7117 A

  According to the embodiment, it is possible to provide a nonaqueous electrolyte battery and a battery pack that are excellent in life performance at high temperatures.

According to the embodiment, a nonaqueous electrolyte battery including a positive electrode, a negative electrode, and a nonaqueous electrolyte is provided. The negative electrode includes at least one negative electrode active material selected from titanium dioxide having a monoclinic structure and a niobium titanium composite oxide. The nonaqueous electrolyte contains an organic solvent, a bisfluorosulfonylimide anion (N (FSO ₂ ) ₂ ⁻ ), and an alkali cation. The positive electrode has a layered structure of Li _x Ni _y Mn _z Co _1-yz O ₂ (0 ≦ x ≦ 1.1, 0.3 ≦ y <1, 0 <z <0.5), and a spinel-structured Li _x Ni _0.5 Mn _1.5 O ₄ (0 ≦ x ≦ 1.1), Li _x Mn _1-w Fe _w PO _{4 having} an olivine structure (0 ≦ x ≦ 1.1, 0.1 ≦ W ≦ 0) .3), a positive electrode active material composed of at least one selected from the group consisting of lithium manganese oxide, sodium iron oxide, and NaFe _0.5 Mn _0.5 O ₂ having a spinel structure. The organic solvent is a mixed solvent of propylene carbonate and at least one selected from the group consisting of diethyl carbonate, dimethyl carbonate, γ-butyrolactone, and ethyl methyl carbonate.

  Moreover, according to embodiment, the battery pack containing a nonaqueous electrolyte battery is provided.

FIG. 1 is a partially cutaway perspective view showing a nonaqueous electrolyte battery according to an embodiment. FIG. 2 is an enlarged cross-sectional view of a part A in FIG. FIG. 3 is a partially cutaway cross-sectional view of the nonaqueous electrolyte battery of the embodiment. FIG. 4 is a side view of the battery of FIG. FIG. 5 is a partially cutaway perspective view schematically showing the nonaqueous electrolyte battery of the embodiment. FIG. 6 is a perspective view illustrating an example of an assembled battery used in the battery pack according to the embodiment. FIG. 7 is a perspective view schematically showing the battery pack according to the embodiment. FIG. 8 is an exploded perspective view of the battery pack according to the embodiment. FIG. 9 is a block diagram showing an electric circuit of the battery pack of FIG.

(First embodiment)
According to the first embodiment, a nonaqueous electrolyte battery including a positive electrode, a negative electrode, and a nonaqueous electrolyte is provided. The negative electrode includes at least one negative electrode active material selected from titanium dioxide having a monoclinic structure and a niobium titanium composite oxide. The nonaqueous electrolyte contains an organic solvent, a bisfluorosulfonylimide anion (N (FSO ₂ ) ₂ ⁻ ), and an alkali cation.

The titanium dioxide and niobium titanium composite oxide having a monoclinic structure is desirably in the form of secondary particles that can easily obtain a high specific surface area in order to obtain electronic conductivity and ionic conductivity. However, in the form of secondary particles, the reductive decomposition of the nonaqueous electrolyte proceeds in a high temperature (for example, 60 ° C. or higher) environment, and the interface resistance of the negative electrode increases. As a cause of this, hydrogen fluoride (HF) generated by hydrolysis of a lithium salt containing F (for example, LiPF ₆ , LiBF ₄ ) reacts with the negative electrode, and the negative electrode surface is coated with an inorganic material mainly composed of LiF. Is generated.

A non-aqueous electrolyte in which an organic solvent contains bisfluorosulfonylimide anion (N (FSO ₂ ) ₂ ⁻ ) and an alkali cation is chemically and electrochemically mixed with titanium dioxide and niobium titanium composite oxide having a monoclinic structure. Side reactions can be suppressed. The bisfluorosulfonylimide anion (N (FSO ₂ ) ₂ ⁻ ) is not decomposed at the lithium occlusion / release potential of the negative electrode containing titanium dioxide or niobium titanium composite oxide having a monoclinic structure, and has excellent thermal stability. Therefore, generation of free hydrofluoric acid can be prevented, and an increase in the interface resistance of the negative electrode under a high temperature environment can be suppressed. As a result, the nonaqueous electrolyte battery including a negative electrode including at least one negative electrode active material selected from titanium dioxide and niobium titanium composite oxide having a monoclinic structure improves high-temperature cycle life performance, output performance, and capacity. be able to. In addition, since this non-aqueous electrolyte can suppress a reaction in which the niobium metal in the niobium-titanium composite oxide is dissolved in the non-aqueous electrolyte under a high-temperature environment, the non-aqueous electrolyte battery having a negative electrode containing the niobium-titanium composite oxide The high temperature cycle can be improved.

  Hereinafter, the nonaqueous electrolyte, the positive electrode, and the negative electrode will be described.

1) Nonaqueous electrolyte The organic solvent contained in the nonaqueous electrolyte is not particularly limited as long as it can dissolve a bisfluorosulfonylimide salt. Examples thereof include cyclic carbonates, chain carbonates, chain ethers, Lactones, sulfones, phosphate esters, fluorinated phosphate esters and nitriles are included.

  Examples of preferred organic solvents include propylene carbonate (PC), ethylene carbonate (EC), butylene carbonate (BC), dimethyl carbonate (DMC), diethyl carbonate (DEC), methyl ethyl carbonate (MEC), γ-butyrolactone (GBL). ), Ethyl methyl sulfone (EMS), ethyl isopropyl sulfone (EiPS), tris (2,2,2-trifluoroethyl) phosphate (TFEP), dimethoxyethane (DME), and diethoxyethane (DEE).

  In addition, the kind of organic solvent can be made into 1 type or 2 types or more.

  By containing at least one selected from the group consisting of PC, EC, GBL, DEC, MEC, DMC, DME, DEE, and TFEP in the organic solvent, the ion conductivity is increased and the high output performance is improved. More preferable organic solvents are a mixed solvent of PC and DEC, a mixed solvent of PC and DMC, a mixed solvent of PC and MEC, a mixed solvent of PC and GBL, a mixed solvent of PC and DME, a mixed solvent of PC and DEE, and PC and It is a mixed solvent of TFEP. By using this mixed solvent, high output performance can be obtained in a low temperature environment. The mixing ratio of PC in the mixed solvent is preferably in the range of 20 to 80% by volume. Within this range, battery operation is possible without solidification even in a low temperature environment of −40 ° C.

  Preferred compositions of the organic solvent containing TFEP include PC and TFEP, PC and DEC and TFEP, and PC, MEC and TFEP. The mixing ratio of TFEP is preferably 20 to 100% by volume. This is because the self-discharge reaction in a high temperature environment is suppressed.

Since the organic solvent containing at least one selected from the group consisting of EMS, EiPS, and TFEP can improve oxidation resistance, Li _x Ni _0.5 Mn _1.5 O ₄ (0 <x ≦ 1.1) and the like, the oxidative decomposition of the nonaqueous electrolyte by the positive electrode containing the positive electrode active material that can obtain a high potential can be suppressed, and a high voltage nonaqueous electrolyte battery can be obtained.

  The alkali cation in the organic solvent is generated when the bisfluorosulfonylimide salt is dissolved in the organic solvent, and examples thereof include lithium ions and sodium ions.

Since Li [N (FSO ₂ ) ₂ ] (LiFSI) and Na [N (FSO ₂ ) ₂ ] (NaFSI) are highly soluble in organic solvents, it is possible to increase the concentration of the lithium salt in the organic solvent. . At least one salt selected from the group consisting of Li [N (FSO ₂ ) ₂ ] and Na [N (FSO ₂ ) ₂ ] can be dissolved in an organic solvent in the range of 0.5 to 3 mol / L. desirable. Within this range, the nonaqueous electrolyte is excellent in ion conductivity and high temperature durability. However, if it is less than this range, the lithium ion concentration at the interface between the positive electrode and the non-aqueous electrolyte may be drastically reduced during discharge with a large current, and the output may be reduced. On the other hand, when the concentration exceeds 3 mol / L, the viscosity of the non-aqueous electrolyte is increased, and the lithium ion migration rate is reduced, which may reduce the output. A more preferable range is 1 to 2 mol / L. Thereby, a high output can be taken out even in a low temperature environment.

Other salts other than Li [N (FSO ₂ ) ₂ ] and Na [N (FSO ₂ ) ₂ ] can be contained. The other salt preferably includes at least one of a lithium salt and a sodium salt. Examples of other salts include NaLiB ₄ , LiBF ₄ , NaLiPF ₆ , LiPF ₆ , NaAsF ₆ , LiAsF ₆ , NaClO ₄ , LiClO ₄ , NaCF ₃ SO ₃ , NaN (CF ₃ SO ₂ ) ₂ , NaN (C _{2 F 5 SO 2) 2, Na} (CF 3 SO 2) 3 C, NaB [(OCO) 2] 2, LiCF 3 SO 3, LiN (CF 3 SO 2) 2, LiN (C 2 F 5 SO 2) 2 Li (CF ₃ SO ₂ ) ₃ C, LiB [(OCO) ₂ ] _{2 and the} like.

The type of other salts used can be one or more. Preferred as another salt is lithium hexafluorophosphate (LiPF ₆ ). The LiPF ₆ concentration in the non-aqueous electrolyte is desirably in the range of 0.01 to 0.4 mol / L. By containing LiPF ₆ in this range, a protective film is formed between the positive electrode active material-containing layer and the positive electrode current collector (for example, Al foil), thereby suppressing an increase in positive electrode resistance under a high temperature and high voltage environment. And high temperature durability performance can be improved. A more preferable salt concentration of the nonaqueous electrolyte is such that the LiFSI concentration is in the range of 0.8 to 2 mol / L and the LiPF ₆ concentration is in the range of 0.1 to 0.3 mol / L.

  As the non-aqueous electrolyte, in addition to a liquid electrolyte prepared by dissolving an electrolyte in an organic solvent, a gel electrolyte obtained by combining a liquid electrolyte and a polymer material can be used. Examples of the polymer material include polyvinylidene fluoride (PVdF), polyacrylonitrile (PAN), polyethylene oxide (PEO), and the like.

2) Positive electrode The positive electrode includes a positive electrode current collector and a positive electrode active material-containing layer (hereinafter referred to as a positive electrode material layer) supported on one or both surfaces of the positive electrode current collector. The positive electrode material layer includes a positive electrode active material, a conductive agent, and a binder.

  For the positive electrode active material, metal compounds that can be electrochemically charged and discharged with alkali ions such as lithium ions and sodium ions, graphite that absorbs anions in the nonaqueous electrolyte, carbon materials, and activated carbon with a capacitor capacity are used. be able to. Examples of the metal compound include metal oxides, metal sulfides, metal fluorides, olivine phosphate compounds, and fluorinated metal sulfate compounds.

  The type of the positive electrode active material can be one type or two or more types.

Examples of the positive electrode active material include Ni-containing layered metal oxide, lithium cobalt oxide (LiCoO ₂ ), spinel lithium manganese oxide (LiMn ₂ O ₄ ), and olivine crystal structure lithium phosphorus. iron (LiFePO _4), lithium manganese phosphate (LiMnPO _4), lithium iron phosphate, manganese _{(LiMn 1-x Fe x PO} 4, 0 <x <0.5), fluorinated lithium iron sulfate (LiFeSO ₄ F) , Spinel crystal structure lithium nickel manganese oxide (Li _x Mn _1.5 Ni _0.5 O ₄ , 0 ≦ x ≦ 1.1 (more preferably 0 <x ≦ 1.1)), sodium iron oxide (NaFeO _2), sodium nickel titanium oxide _{(NaNi 1-f Ti f O} 2, 0 ≦ f ≦ 1), Na trim nickel iron oxide (NaNi _1-f Fe _f O ₂ , 0 ≦ f ≦ 1), sodium nickel manganese oxide (NaNi _1-f Mn _f O ₂ , 0 ≦ f ≦ 1), sodium-containing phosphate polyanionic material (for example, Na ₃ V ₂ (PO ₄ ) ₃ , Na ₂ FePO ₄ F, Na ₃ V ₂ (PO ₄ ) ₂ F ₃ , Na ₄ Ni ₃ (PO ₄ ) ₂ P ₂ O ₇ , Na ₄ Mn ₃ (PO ₄ ) ₂ P ₂ O ₇ ), etc. Is mentioned.

Examples of metal oxides containing Ni and having a layered structure include nickel-containing oxides (Li _x NiO ₂ , 0 ≦ x ≦ 1.1), nickel cobalt-containing oxides (Li _x Ni _y Co _1-y O ₂ , 0 ≦ x ≦ 1.1, 0.3 ≦ y <1), nickel cobalt aluminum-containing oxide (Li _x Ni _z Co _1-y Al _1-yz O ₂ , 0 ≦ x ≦ 1. 1, 0.3 ≦ y <1, 0 <z <0.5), nickel cobalt manganese-containing oxide (Li _x Ni _z Co _1-y Mn _1-yz O ₂ , 0 ≦ x ≦ 1.1 0.3 ≦ y <1, 0 <z <0.5) and the like. A more preferable range of x is 0 <x ≦ 1.1. When the metal oxide containing Ni is represented by the general formula Li _x Ni _y M _1-y O ₂ (M is a metal other than Ni, 0 ≦ x ≦ 1.1), y is in the range of 0.5 to 1. Is preferred. Within this range, a high capacity (high energy density) can be obtained. Further, by combining at least one kind of negative electrode active material selected from titanium dioxide having a monoclinic structure and a niobium titanium composite oxide, high-temperature cycle life performance, high output performance, and safety performance can be significantly improved. From the viewpoint of cycle life performance, iron-containing oxides such as LiFePO ₄ and NaFeO ₂ are preferable. From the battery capacity, Li _x Ni _y M _1-y O ₂ (M is a metal other than Ni) is preferable.

Preferred positive electrode active materials include layered Li _x Ni _y Mn _z Co _1-yz O ₂ (0 ≦ x ≦ 1.1, 0.3 ≦ y <1, 0 <z <0.5), Li _x Ni _0.5 Mn _1.5 O _{4 with} spinel structure (0 ≦ x ≦ 1.1), Li _x Mn _1-w Fe _w PO _{4 with} olivine structure (0 ≦ x ≦ 1.1, 0 ≦ w) ≦ 1 (more preferable range is 0.1 ≦ W ≦ 0.3)), Li _x Mn _1-w Fe _w SO ₄ F (0 ≦ x ≦ 1.1, 0 ≦ w ≦ 1 (more preferable range is 0) .8 ≦ w ≦ 1)), and one or more selected from these can be used. A more preferable range of x is 0 <x ≦ 1.1. As a result, a high capacity can be taken out at a high voltage of 3 V or more, and the capacity of the battery can be increased. More preferable positive electrode active materials include Li _x Mn _1-w Fe _w SO ₄ F (0 ≦ x ≦ 1.1, 0 ≦ w ≦ 1), compounds having an olivine structure, such as Li _x FePO ₄ (0 ≦ x ≦ 1.1), Li _x MnPO ₄ (0 ≦ x ≦ 1.1), Li _x Mn _1-w Fe _w PO ₄ (0 ≦ x ≦ 1.1, 0 ≦ W ≦ 1). By using each positive electrode active material, the cycle life performance under a high temperature environment is greatly improved. The non-aqueous electrolyte containing N (FSO ₂ ) ₂ ^— and an organic solvent suppresses dissolution of metal ions (eg, Fe, Mn, Ni, etc.) in the positive electrode active material in the non-aqueous electrolyte under a high temperature environment. Therefore, high temperature cycle life performance and high temperature storage performance can be improved.

  Note that the amount of lithium in the positive electrode active material varies depending on the end-of-charge voltage of the nonaqueous electrolyte battery, and the amount of lithium decreases as the charge voltage increases.

  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 19% by weight of the conductive agent, and 1 to 7% by weight of the binder.

The positive electrode is produced, for example, by suspending a positive electrode active material, a conductive agent, and a binder in an appropriate solvent, applying the suspension to a positive electrode current collector, drying, and pressing. The specific surface area by the BET method of the positive electrode active material is measured by a method described later, and is preferably in the range of 0.1 to ⁵ m ² / g.

  The average particle diameter of the positive electrode active material particles is preferably 0.1 μm or more and 20 μm or less.

  Examples of the positive electrode current collector include an aluminum foil and an aluminum alloy foil. The thickness of the positive electrode current collector is preferably 20 μm or less, and more preferably 15 μm or less.

3) Negative electrode This negative electrode includes a negative electrode current collector and a negative electrode active material-containing layer (hereinafter referred to as a negative electrode material layer) carried on one or both surfaces of the negative electrode current collector. The negative electrode material layer includes a negative electrode active material, a conductive agent, and a binder.

  The negative electrode active material is at least one selected from titanium dioxide having a monoclinic structure and niobium titanium composite oxide. An irreversible capacity may be generated during charging and discharging, and lithium may remain in the negative electrode active material. For this reason, the negative electrode active material may contain lithium. The type of the negative electrode active material can be one type or two or more types.

Titanium dioxide having a monoclinic structure can be expressed as TiO ₂ (B) having a monoclinic structure (hereinafter referred to as TiO ₂ (B)). TiO ₂ (B) is preferably subjected to heat treatment in the range of 300 to 500 ° C. Furthermore, it is preferable to contain 0.5 to 10% by weight of Nb in TiO ₂ (B). Thereby, the negative electrode capacity can be increased.

Examples of the niobium titanium composite oxide include Li _a Nb ₂ TiO ₇ (0 ≦ a ≦ 5), Li _a Nb ₂ Ti ₂ O ₉ (0 ≦ a ≦ 5), Li _a NbTiO ₅ (0 ≦ a ≦ 5). Li _a TiM _b Nb _{2 ± β} O _{7 ± σ} (0 ≦ a ≦ 5, 0 ≦ b ≦ 0.3, 0 ≦ β ≦ 0.3, 0 ≦ σ ≦ 0.3, where M is Fe, V, And at least one element selected from the group consisting of Mo and Ta). The niobium titanium composite oxide having each composition preferably has a monoclinic structure. Further, the niobium titanium composite oxide represented by Li _a TiM _b Nb _{2 ± β} O _{7 ± σ} is preferably subjected to heat treatment in the range of 800 ° C. to 1200 ° C. Accordingly, the true density of the niobium titanium composite oxide can be increased and the volume specific capacity can be increased, so that the battery capacity can be improved.

  The negative electrode active material particles may be those in which primary particles or secondary particles exist alone, or those in which primary particles and secondary particles are mixed.

  The particles of the negative electrode active material preferably have a carbon material attached to the surface. This increases the electron conduction network inside the electrode, reduces the electrode resistance, and improves the high current performance.

The negative electrode active material desirably has a specific surface area of 3 m ² / g or more and 50 m ² / g or less by the BET method using N ₂ adsorption. Thereby, the high temperature cycle performance and output performance of a nonaqueous electrolyte battery can be improved.

The negative electrode material layer is porous, and it is desirable that the surface area (specific surface area of the negative electrode) per 1 g of the negative electrode material layer (excluding the weight of the current collector) be in the range of 3 m ² / g to 50 m ² / g. A more preferable range of the specific surface area is 5 to 50 m ² / g.

  The porosity of the negative electrode (excluding the current collector) is desirably in the range of 20 to 50%. Thereby, it is possible to obtain a negative electrode having excellent affinity between the negative electrode and the non-aqueous electrolyte and a high density. A more preferable range of the porosity is 25 to 40%.

The negative electrode active material particles preferably include secondary particles. In this case, the negative electrode active material particles have an average particle size of 10 μm or less, a primary particle size (diameter) of 1 μm or less, and a specific surface area in the BET method by N ₂ adsorption of 3 to 50 m ² / g. Is desirable. The average particle diameter of the negative electrode active material particles can be regarded as the diameter of the secondary particles. Since the negative electrode active material particles can further reduce the affinity for the nonaqueous electrolyte while suppressing the reduction side reaction in a high temperature environment, the high temperature cycle life performance and thermal stability of the nonaqueous electrolyte battery can be improved. Can be improved. The lower limit value of the average particle size is desirably 0.5 μm. Moreover, it is desirable that the lower limit value of the primary particle diameter be 0.1 μm.

  The negative electrode current collector is preferably an aluminum foil or an aluminum alloy foil.

  The thickness of the aluminum foil and the aluminum alloy foil is 20 μm or less, more preferably 15 μm or less. The purity of the aluminum foil is preferably 99.99% by weight or more. The aluminum alloy is preferably an alloy containing one or more elements selected from the group consisting of magnesium, zinc and silicon. On the other hand, transition metals such as iron, copper, nickel, and chromium are preferably 100 ppm by weight or less.

As the conductive agent, for example, a carbon material, aluminum powder, TiO, or the like can be used. Examples of the carbon material include acetylene black, carbon black, coke, carbon fiber, and graphite. More preferably, coke having a heat treatment temperature of 800 ° C. to 2000 ° C. and an average particle diameter of 10 μm or less, graphite, TiO powder, and carbon fiber having an average fiber diameter of 1 μm or less are preferable. The BET specific surface area by N ₂ adsorption of the carbon material is preferably 10 m ² / g or more.

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

  The mixing ratio of the negative electrode active material, the conductive agent and the binder is preferably in the range of 80 to 95% by weight of the negative electrode active material, 3 to 18% by weight of the conductive agent, and 2 to 7% by weight of the binder.

  The negative electrode is produced by suspending a negative electrode active material, a conductive agent and a binder in an appropriate solvent, applying the suspension to a current collector, drying, and applying a press (for example, a warming press). The

  The nonaqueous electrolyte battery may include a separator and an exterior member in addition to the positive electrode, the negative electrode, and the nonaqueous electrolyte.

  Hereinafter, the separator and the exterior member will be described.

4) Separator A separator can be disposed between the positive electrode and the negative electrode. Examples of the separator include a synthetic resin nonwoven fabric, a porous film, and a cellulose nonwoven fabric. A porous film can be formed from polyolefin, such as polyethylene and a polypropylene, for example.

5) Exterior member A metal container or a laminate film container can be used for the exterior member in which the positive electrode, the negative electrode, and the nonaqueous electrolyte are accommodated.

  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. Further, the plate thickness of the container is desirably 0.5 mm or less, and a more preferable range is 0.3 mm or less.

  Examples of the laminate film include a multilayer film in which an aluminum foil is covered with a resin film. As the resin, polymers such as polypropylene (PP), polyethylene (PE), nylon, polyethylene terephthalate (PET) can be used. The thickness of the laminate film is preferably 0.2 mm or less. The purity of the aluminum foil is preferably 99.5% by weight or more.

  The metal can made of an aluminum alloy is preferably an alloy having an aluminum purity of 99.8% by weight or less containing one or more elements selected from the group consisting of manganese, magnesium, zinc and silicon. The strength of the metal can made of an aluminum alloy is dramatically increased, and thus the thickness of the can can be reduced. As a result, a thin, lightweight, high output and excellent heat dissipation battery can be realized.

  The non-aqueous electrolyte battery of the embodiment can be applied to various forms of non-aqueous electrolyte batteries such as a square, cylindrical, flat, thin, coin type, etc. Examples include a rectangular battery or a cylindrical battery using a manufactured exterior member, and a thin battery using a laminated film exterior member. An example of the nonaqueous electrolyte battery will be described with reference to FIGS.

  1 and 2 show an example of a non-aqueous electrolyte battery using a laminate-fill exterior member.

  The laminated electrode group 1 is housed in a bag-like container 2 made of a laminate film having a metal layer interposed between two resin films. As shown in FIG. 2, the stacked electrode group 1 has a structure in which positive electrodes 3 and negative electrodes 4 are alternately stacked with separators 5 interposed therebetween. There are a plurality of positive electrodes 3, each of which includes a current collector 3 a and a positive electrode active material-containing layer 3 b formed on both surfaces of the current collector 3 a. A plurality of negative electrodes 4 are present, each including a current collector 4a and a negative electrode active material-containing layer 4b formed on both surfaces of the current collector 4a. One side of the current collector 4 a of each negative electrode 4 protrudes from the positive electrode 3. The protruding current collector 4 a is electrically connected to the strip-shaped negative electrode terminal 6. The tip of the strip-like negative electrode terminal 6 is drawn out from the container 2 to the outside. Although not shown, the current collector 3a of the positive electrode 3 has a side protruding from the negative electrode 4 on the side opposite to the protruding side of the current collector 4a. The current collector 3 a protruding from the negative electrode 4 is electrically connected to the belt-like positive electrode terminal 7. The tip of the strip-like positive electrode terminal 7 is located on the opposite side to the negative electrode terminal 6 and is drawn out from the side of the container 2 to the outside.

  3 and 4 show an example of a non-aqueous electrolyte battery using a metal container.

  The electrode group 11 is housed in a rectangular cylindrical metal container 12. The electrode group 11 has a structure in which a positive electrode 13 and a negative electrode 14 are wound in a spiral shape so that a flat shape is formed with a separator 15 interposed therebetween. A nonaqueous electrolyte (not shown) is held by the electrode group 11. As shown in FIG. 4, a strip-like positive electrode lead 16 is electrically connected to each of a plurality of locations at the end of the positive electrode 13 located on the end face of the electrode group 1. In addition, a strip-like negative electrode lead 17 is electrically connected to each of a plurality of locations at the end of the negative electrode 14 located on this end face. The plurality of positive electrode leads 16 are electrically connected to the positive electrode conductive tab 18 in a bundled state. A positive electrode terminal is constituted by the positive electrode lead 16 and the positive electrode conductive tab 18. The negative electrode lead 17 is connected to the negative electrode conductive tab 19 in a bundled state. The negative electrode lead 17 and the negative electrode conductive tab 19 constitute a negative electrode terminal. The metal sealing plate 20 is fixed to the opening of the metal container 12 by welding or the like. The positive electrode conductive tab 18 and the negative electrode conductive tab 19 are each drawn out from an extraction hole provided in the sealing plate 20. The inner peripheral surface of each extraction hole of the sealing plate 20 is covered with an insulating member 21 in order to avoid a short circuit due to contact with the positive electrode conductive tab 18 and the negative electrode conductive tab 19.

  FIG. 5 shows another example of a nonaqueous electrolyte battery using a metal container.

  The flat or thin nonaqueous electrolyte battery shown in FIG. 5 is a rectangular parallelepiped aluminum alloy container 22, an electrode group 23 housed in the container 22, and housed in the container 22 and held by the electrode group 23. Non-aqueous electrolyte (not shown). The electrode group 23 has a structure in which a positive electrode 24 and a negative electrode 25 are wound in a spiral shape so that a flat shape is formed with a separator 26 interposed therebetween. The electrode group 23 is produced, for example, by winding a positive electrode 24 and a negative electrode 25 in a spiral shape with a separator 26 interposed therebetween, and then applying a heat press. The strip-like positive electrode lead 27 is electrically connected to the positive electrode 24. On the other hand, the strip-shaped negative electrode lead 28 is electrically connected to the negative electrode 25. The positive electrode lead 27 is electrically connected to the container 22, and the negative electrode lead 28 is electrically connected to a negative electrode terminal 29 that is insulated from the container 22.

According to the nonaqueous electrolyte battery of the first embodiment described above, a negative electrode including at least one negative electrode active material selected from titanium dioxide and niobium titanium composite oxide having a monoclinic structure, an organic solvent, N ( FSO _{2) 2} ^- and order and a non-aqueous electrolyte containing an alkali cation, there can be provided a nonaqueous electrolyte battery excellent in high-temperature cycle life performance and high-current discharge performance.

(Second Embodiment)
According to 2nd Embodiment, the assembled battery which uses a nonaqueous electrolyte battery as a unit cell, and the battery pack containing this assembled battery can be provided. The battery pack of the second embodiment can be used for the nonaqueous electrolyte battery.

  Examples of the assembled battery include a plurality of unit cells electrically connected in series or in parallel as a constituent unit, a unit composed of a plurality of unit cells electrically connected in series, or electrically connected in parallel Examples include a unit including a unit composed of a plurality of unit cells.

  Examples of a form in which a plurality of non-aqueous electrolyte batteries are electrically connected in series or in parallel include those in which a plurality of batteries each having an exterior member are electrically connected in series or in parallel, and are accommodated in a common housing. In addition, a plurality of electrode groups electrically connected in series or in parallel are included. In the former specific example, the positive terminals and the negative terminals of a plurality of nonaqueous electrolyte batteries are connected by a metal bus bar (for example, aluminum, nickel, copper). In the latter specific example, a plurality of electrode groups are accommodated in a single casing in an electrochemically insulated state by partition walls, and these electrode groups are electrically connected in series. By setting the number of electrically connected batteries in the range of 5 to 7, the voltage compatibility with the lead storage battery is improved. In order to further increase the voltage compatibility with the lead storage battery, a configuration in which five or six unit cells are connected in series is preferable.

  A metal can, a plastic container, or the like made of aluminum alloy, iron, stainless steel, or the like can be used for a housing in which the assembled battery is stored. Further, the plate thickness of the container is desirably 0.5 mm or more.

An example of the assembled battery will be described with reference to FIG. The assembled battery 31 shown in FIG. 6 includes a plurality of prismatic nonaqueous electrolyte batteries 32 _{1 to} 32 _{5 according} to the first embodiment as unit cells. The positive electrode conductive tab 18 of the battery 32 ₁ and the negative electrode conductive tab 19 of the battery 32 ₂ located adjacent thereto are electrically connected by a lead 33. Further, the positive electrode conductive tab 18 of the battery 32 ₂ and the negative electrode conductive tab 19 of the battery 32 ₃ located adjacent thereto are electrically connected by a lead 33. In this way, the batteries 32 _{1 to} 32 ₅ are connected in series.

In addition, an example of a battery pack provided with the assembled battery including the nonaqueous electrolyte battery shown in FIGS. 1 and 2 will be described with reference to FIG. The battery pack 40 includes a housing 41 and an assembled battery 42 accommodated in the housing 41. Battery pack 42 is to nonaqueous electrolyte battery 43 _{1-43 5} a plurality (e.g. five) are electrically connected in series. A nonaqueous electrolyte battery ₄₃ 1-43 ₅ is laminated in the thickness direction. The housing 41 has an opening 44 on each of the upper part and the four side surfaces. Side nonaqueous electrolyte battery ₄₃ 1-43 ₅ positive and negative electrode terminals 6 and 7 are protruded is exposed to the opening 44 of the housing 41. Output positive terminal of the assembled battery 42 45 form a strip, one end is electrically connected to the 6 one of the positive terminal of the nonaqueous electrolyte battery 43 _{1-43 5,} and the other end of the housing 41 opening 44 protrudes from the upper portion of the housing 41. On the other hand, the output negative terminal 46 of the assembled battery 42, without a band, one end of which is connected one of the negative electrode terminal 7 and electrically non-aqueous electrolyte battery 43 _{1-43 5,} and the other end of the housing 41 It protrudes from the opening 44 and protrudes from the upper part of the housing 41.

  Another example of the battery pack will be described in detail with reference to FIGS. A plurality of unit cells 51 composed of a flat type non-aqueous electrolyte battery are stacked so that the negative electrode terminal 52 and the positive electrode terminal 53 extending to the outside are aligned in the same direction, and are assembled by fastening with an adhesive tape 54. A battery 55 is configured. These unit cells 51 are electrically connected to each other in series as shown in FIG.

  The printed wiring board 56 is disposed to face the side surface of the unit cell 51 from which the negative electrode terminal 52 and the positive electrode terminal 53 extend. As shown in FIG. 9, a thermistor 57, a protection circuit 58, and a terminal 59 for energizing an external device are mounted on the printed wiring board 56. An insulating plate (not shown) is attached to the surface of the printed wiring board 56 facing the assembled battery 55 in order to avoid unnecessary connection with the wiring of the assembled battery 55.

  The positive electrode lead 60 is connected to the positive electrode terminal 53 located at the lowermost layer of the assembled battery 55, and the tip thereof is inserted into and electrically connected to the positive electrode connector 61 of the printed wiring board 56. The negative electrode lead 62 is connected to the negative electrode terminal 52 located on the uppermost layer of the assembled battery 55, and the tip thereof is inserted into and electrically connected to the negative electrode side connector 63 of the printed wiring board 56. These connectors 61 and 63 are connected to the protection circuit 58 through wirings 64 and 65 formed on the printed wiring board 56.

  The thermistor 57 detects the temperature of the unit cell 51, and the detection signal is transmitted to the protection circuit 58. The protection circuit 58 can cut off the plus wiring 66a and the minus wiring 66b between the protection circuit 58 and the energization terminal 59 to the external device under a predetermined condition. The predetermined condition is, for example, when the temperature detected by the thermistor 57 is equal to or higher than a predetermined temperature. The predetermined condition is when an overcharge, overdischarge, overcurrent, or the like of the unit cell 51 is detected. This detection of overcharge or the like is performed for each unit cell 51 or the assembled battery 55. When detecting each unit cell 51, 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 51. 8 and 9, a voltage detection wiring 67 is connected to each unit cell 51, and a detection signal is transmitted to the protection circuit 58 through the wiring 67.

  Protective sheets 68 made of rubber or resin are disposed on the three side surfaces of the assembled battery 55 excluding the side surfaces from which the positive electrode terminal 53 and the negative electrode terminal 52 protrude.

  The assembled battery 55 is stored in a storage container 69 together with each protective sheet 68 and the printed wiring board 56. That is, the protective sheet 68 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 69, and the printed wiring board 56 is disposed on the inner side surface on the opposite side in the short side direction. The assembled battery 55 is located in a space surrounded by the protective sheet 68 and the printed wiring board 56. The lid 70 is attached to the upper surface of the storage container 69.

  In addition, instead of the adhesive tape 54, a heat shrink tape may be used for fixing the assembled battery 55. In this case, protective sheets are arranged on both side surfaces of the assembled battery, the heat shrinkable tape is circulated, and then the heat shrinkable tape is heat shrunk to bind the assembled battery.

  8 and 9, the unit cells 51 are connected in series, but may be connected in parallel in order to increase the battery capacity. The assembled battery packs can be connected in series or in parallel.

  Moreover, the aspect of a battery pack is changed suitably by a use. As a use of the battery pack, one in which charging / discharging with 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.

  According to the second embodiment described above, since the nonaqueous electrolyte battery according to the first embodiment is used, the assembled battery and the battery pack with improved charge / discharge cycle life performance and high-current discharge performance under a high temperature environment. Can be provided. For this reason, it becomes possible to provide an assembled battery and a battery pack suitable as an alternative power source for a lead battery used as a starter power source for a vehicle or as an in-vehicle secondary battery mounted on a hybrid vehicle.

[Example]
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the embodiments described below.

Example 1
Lithium nickel manganese cobalt composite oxide (LiNi _0.8 Mn _0.1 Co _0.1 O ₂₎ having a layered structure with an average particle diameter of 3 μm and a specific surface area of 0.8 m ² / g by BET method using N ₂ adsorption as the positive electrode active material ), 8% by weight of graphite powder with respect to the whole positive electrode as a conductive material, and 5% by weight of PVdF with respect to the whole positive electrode as a binder, and dispersed in an n-methylpyrrolidone (NMP) solvent. To prepare a slurry. The obtained slurry was applied to both sides of an aluminum alloy foil (purity 99%) having a thickness of 15 μm, dried, and a positive electrode having an electrode density of 3.2 g / cm ³ was produced through a pressing process. The specific surface area of the positive electrode material layer was 0.5 m ² / g.

Further, Nb ₂ TiO ₇ particles having a monoclinic structure were prepared as the negative electrode active material. The Nb ₂ TiO ₇ particles contain secondary particles, the average particle size was 5 μm, and the average primary particle size was 0.3 μm. The average particle size is considered as the secondary particle size. The BET specific surface area of the Nb ₂ TiO ₇ particles was 10 m ² / g. N-Methylpyrrolidone by blending Nb ₂ TiO ₇ particles, graphite powder having an average particle diameter of 5 μm and a BET specific surface area of 10 m ² / g, and PVdF as a binder in a weight ratio of 90: 6: 4. A slurry was prepared by dispersing in (NMP) solvent and using a ball mill with stirring at a rotational speed of 1000 rpm and stirring time of 2 hours. The obtained slurry was applied to an aluminum alloy foil (purity: 99.3%) having a thickness of 15 μm, dried, and subjected to a heating press process, thereby producing an electrode density of 2.2 g / cm ³ negative electrode. The negative electrode porosity excluding the current collector was 35%. Further, the BET specific surface area of the negative electrode material layer (surface area per 1 g of the negative electrode material layer) was 8 m ² / g.

  On the other hand, the positive electrode was covered with a separator made of cellulose nonwoven fabric having a thickness of 20 μm, the negative electrode was stacked on the separator so as to face the positive electrode via the separator, and these were wound in a spiral shape to produce an electrode group. This electrode group was further pressed into a flat shape. The electrode group was housed in a bottomed rectangular cylindrical metal can made of an aluminum alloy (Al purity 99 wt%) having a thickness of 0.5 mm.

Propylene carbonate (PC) and tris (2,2,2-trifluoroethyl) phosphate (TFEP) were mixed at a volume ratio of 1: 2, and Li [N (FSO ₂ ) ₂ was used as an electrolyte in the resulting mixed organic solvent. 1 mol / L and LiPF ₆ 0.1 mol / L were dissolved to prepare a liquid non-aqueous electrolyte (non-aqueous electrolyte). This nonaqueous electrolyte was poured into an electrode group in a metal can, and a thin or square nonaqueous electrolyte battery having the structure shown in FIG. 1 and having a thickness of 13 mm, a width of 62 mm, and a height of 94 mm was produced.

(Examples 2 to 24)
A nonaqueous electrolyte battery was produced in the same manner as described in Example 1 except that the nonaqueous electrolyte, the organic solvent composition, the negative electrode active material, and the positive electrode active material were those shown in Table 1 below.

(Comparative Examples 1-14)
A nonaqueous electrolyte battery was produced in the same manner as described in Example 1 except that the nonaqueous electrolyte, the organic solvent composition, the negative electrode active material, and the positive electrode active material were those shown in Table 2 below.

  About the nonaqueous electrolyte battery of the obtained Example and Comparative Example, after charging at a constant current of 4 A at 25 ° C. for 1 hour to the end-of-charge voltage, the discharge capacity and average voltage when discharged at 4 A to the end-of-discharge voltage Measurement and energy capacity (Wh) were obtained. Further, the discharge capacity maintenance rate at the time of 4A (equivalent to 1C) discharge at 25 ° C. was set to 100%, and the discharge capacity maintenance rate at the time of 40A (equivalent to 10C) discharge at 25 ° C. was measured. As a high-temperature cycle test, a cycle test was performed in which a constant current of 4 A was charged at 60 ° C. to a charge end voltage in 1 hour, and then a constant current discharge of 4 A was repeated until the discharge end voltage. The cycle life at the cycle test at 60 ° C. was defined as the number of cycles at a capacity maintenance rate of 80% of the initial capacity.

The measurement results are shown in Tables 3 and 4 below. Tables 3 and 4 show the charge end voltage and discharge end voltage in the above test.

  As is apparent from Tables 1 to 4, Examples 1 to 24 are superior to Comparative Examples 1 to 14 in 60 ° C. high-temperature cycle life performance.

In addition, by comparing Example 24 and Comparative Example 13, a negative electrode active material made of lithium titanate was used even though a nonaqueous electrolyte containing an organic solvent, N (FSO ₂ ) ₂ ^—, and an alkali cation was provided. According to Comparative Example 13, it can be seen that the energy capacity and 60 ° C. high temperature cycle life performance are inferior to Example 24. This is because the self-discharge of the negative electrode is promoted by the phosphate compound having an olivine structure, and the capacity balance between the positive electrode and the negative electrode is lost.

By comparing Example 8 and Comparative Example 14, a negative electrode active material made of titanium dioxide having an anatase structure was used even though a nonaqueous electrolyte containing an organic solvent, N (FSO ₂ ) ₂ ^— and an alkali cation was provided. According to Comparative Example 14, it can be seen that the energy capacity, 10C discharge capacity retention rate, and 60 ° C. high temperature cycle life performance are inferior to Example 8. When the negative electrode active material made of titanium dioxide with anatase structure is made finer and the specific surface area is increased, the charge / discharge cycle proceeds smoothly, but reductive decomposition of the nonaqueous electrolyte occurs in a high temperature environment and the interface resistance increases. The charge / discharge cycle performance at high temperatures is degraded. The inferior energy capacity, 10C discharge capacity retention rate, and 60 ° C. high temperature cycle life performance of the battery of Comparative Example 14 are thought to be due to reductive decomposition of the nonaqueous electrolyte.

  Further, when lithium titanate or anatase-structured titanium dioxide is used as the negative electrode active material, the high temperature life performance and thermal stability of the battery are reduced when the positive electrode active material is made fine particles to increase the specific surface area.

The measurement method of the average particle diameter of the negative electrode active material used in the examples, the BET specific surface area by N ₂ adsorption, and the porosity of the negative electrode is shown below.

1) Method for measuring particles of negative electrode active material Using a laser diffraction distribution measuring device (Shimadzu SALD-300), first add about 0.1 g of a sample, a surfactant and 1 to 2 mL of distilled water to a beaker. After sufficiently stirring, the mixture is poured into a stirring water tank and the luminous intensity distribution is measured 64 times at intervals of 2 seconds to obtain particle size distribution data. When two peaks are detected in the particle size distribution, a cumulative volume frequency of 100% or 50% is set for each peak, and a particle size (D50) with a cumulative volume frequency of 50% is determined for each peak. The average particle size of the primary particles and the larger one are the average particle size of the secondary particles. When there is one peak in the particle size distribution, the particle size (D50) having a cumulative volume frequency of 50% is defined as the average particle size of the secondary particles. After measuring the average particle size of the secondary particles, the negative electrode active material particles are forcibly pulverized using a ball mill or the like to obtain primary particles alone. Next, the particle size distribution is measured under the same conditions as described above using a laser diffraction distribution measuring device (Shimadzu SALD-300), and the particle size (D50) having a cumulative volume frequency of 50% is used as the average particle size of the primary particles. .

2) N ₂ BET specific surface area by N ₂ adsorption BET specific surface area anode active material and the negative electrode by adsorption was measured under the following conditions.

Two pieces of 1 g of powdered negative electrode active material or ² × ² cm ² negative electrodes were cut out and used as samples. A BET specific surface area measuring apparatus manufactured by Yuasa Ionics was used, and nitrogen gas was used as an adsorption gas.

For the positive electrode active material and the positive electrode, the BET specific surface area by N ₂ adsorption is measured in the same manner as in the case of the negative electrode, except that 1 g of powdered positive electrode active material or 2 × 2 cm ² positive electrodes are used.

3) Porosity of the negative electrode The porosity of the negative electrode is determined by comparing the volume of the negative electrode material layer with the volume of the negative electrode material layer when the porosity is 0%, and the increase from the volume of the negative electrode material layer when the porosity is 0%. This is calculated by regarding the minute as the pore volume. Note that the volume of the negative electrode material layer is the sum of the volumes of the negative electrode material layers on both sides when the negative electrode material layers are formed on both sides of the current collector.

According to these embodiments or examples, a negative electrode including at least one negative electrode active material selected from titanium dioxide and niobium titanium composite oxide having a monoclinic structure, an organic solvent, N (FSO ₂ ) ₂ ^—, and Since it comprises a non-aqueous electrolyte containing an alkali cation, a non-aqueous electrolyte battery excellent in high-temperature cycle life performance and large current discharge performance can be provided.

In addition, although some embodiment of this invention was described, these embodiment is shown as an example and is not intending limiting the range of invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.
Hereinafter, the invention described in the scope of claims of the present application will be appended.
[1] a positive electrode;
A negative electrode containing at least one negative electrode active material selected from titanium dioxide and niobium titanium composite oxide having a monoclinic structure;
A non-aqueous electrolyte comprising an organic solvent, a bisfluorosulfonylimide anion and an alkali cation; and
Including non-aqueous electrolyte battery.
[2] The organic solvent is propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, γ-butyrolactone, ethyl methyl sulfone, ethyl isopropyl sulfone, tris phosphate (2,2,2-tri The nonaqueous electrolyte battery according to [1], comprising at least one selected from the group consisting of fluoroethyl), dimethoxyethane, and diethoxyethane.
[3] The nonaqueous electrolyte according to [1] or [2], wherein the nonaqueous electrolyte further includes lithium hexafluorophosphate having a concentration in the organic solvent of 0.01 to 0.4 mol / L. Electrolyte battery.
[4] The titanium dioxide having the monoclinic structure is represented by TiO ₂ (B), and the niobium titanium composite oxide is composed of Li _a TiM _b Nb _{2 ± β} O _{7 ± σ} (0 ≦ a ≦ 5, 0 ≦ b ≦ 0.3, 0 ≦ β ≦ 0.3, 0 ≦ σ ≦ 0.3, M is at least one element selected from the group consisting of Fe, V, Mo and Ta) The nonaqueous electrolyte battery according to any one of [1] to [3].
[5] The positive electrode has a layered structure of Li _x Ni _y Mn _z Co _1-yz O ₂ (0 ≦ x ≦ 1.1, 0.3 ≦ y <1, 0 <z <0.5), Li _x Ni _0.5 Mn _1.5 O _{4 with} spinel structure (0 ≦ x ≦ 1.1), Li _x Mn _1-w Fe _w PO _{4 with} olivine structure (0 ≦ x ≦ 1.1, 0 ≦ w) ≦ 1) and at least one positive electrode active material selected from the group consisting of Li _x Mn _1-w Fe _w SO ₄ F (0 ≦ x ≦ 1.1, 0 ≦ w ≦ 1), [1] -The nonaqueous electrolyte battery in any one of [4].
[6] A battery pack including the nonaqueous electrolyte battery according to any one of [1] to [5].

DESCRIPTION OF SYMBOLS 1,11,23 ... Electrode group, 2 ... Exterior member, 3, 13, 24 ... Positive electrode, 3a ... Positive electrode collector, 3b ... Positive electrode active material containing layer, 4, 14, 25 ... Negative electrode, 4a ... Negative electrode current collector Body, 4b ... negative electrode active material containing layer, 5, 15, 26 ... separator, 6 ... negative electrode terminal, 7 ... positive electrode terminal, 12 ... metal container, 16, 27 ... positive electrode lead, 17, 28 ... negative electrode lead, 18 ... positive electrode conductive tab 19 ... negative electrode conductive tab 20 ... sealing plate, 21: insulating member, 31 ... battery assembly 32 _{1-32 5, 43} 1-43 5 _... non-aqueous electrolyte battery, 33 ... lead, 40 ... battery pack , 41 ... housing, 42 ... assembled battery, 44 ... opening, 45 ... output positive terminal, 46 ... output negative terminal, 51 ... unit cell, 55 ... assembled battery, 56 ... printed wiring board, 57 ... thermistor, 58 .. protection circuit, 59... Terminal for energizing external equipment.

Claims (5)

Li _x Ni _y Mn _z Co _1-yz O ₂ (0 ≦ x ≦ 1.1, 0.3 ≦ y <1, 0 <z <0.5) having a layered structure, Li _x Ni _{0 having} a spinel structure _.5 Mn _1.5 O ₄ (0 ≦ x ≦ 1.1), Li _x Mn _1-w Fe _w PO _{4 having} an olivine structure (0 ≦ x ≦ 1.1, 0.1 ≦ W ≦ 0.3) A positive electrode comprising at least one positive electrode active material selected from the group consisting of lithium manganese oxide having a spinel structure, sodium iron oxide, and NaFe _0.5 Mn _0.5 O ₂ ;
A negative electrode containing at least one negative electrode active material selected from titanium dioxide and niobium titanium composite oxide having a monoclinic structure;
Organic solvent, and a nonaqueous electrolyte containing a bisfluorosulfonylimide anion and alkali cations seen including,
The non-aqueous electrolyte battery , wherein the organic solvent is a mixed solvent of propylene carbonate and at least one selected from the group consisting of diethyl carbonate, dimethyl carbonate, γ-butyrolactone, and ethyl methyl carbonate . The nonaqueous electrolyte battery according to claim 1, wherein a mixing ratio of propylene carbonate in the mixed solvent is in a range of 20 to 80% by volume .   The nonaqueous electrolyte battery according to claim 1 or 2, wherein the nonaqueous electrolyte further includes lithium hexafluorophosphate having a concentration in the organic solvent of 0.01 to 0.4 mol / L. The titanium dioxide having the monoclinic structure is represented by TiO ₂ (B), and the niobium titanium composite oxide has a monoclinic structure of Li _a TiM _b Nb _{2 ± β} O _{7 ± σ} (0 ≦ a ≦ 5, 0 ≦ b ≦ 0.3, 0 ≦ β ≦ 0.3, 0 ≦ σ ≦ 0.3, M is at least one element selected from the group consisting of Fe, V, Mo and Ta), Item 4. The nonaqueous electrolyte battery according to any one of Items 1 to 3.   The battery pack containing the nonaqueous electrolyte battery of any one of Claims 1-4.

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