JP4237659B2 - Non-aqueous electrolyte battery - Google Patents

Description

  The present invention relates to a non-aqueous electrolyte battery.

  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 a secondary power source that is a driving source of the electronic devices is also demanded to be smaller, lighter, and have higher energy density. In response to these demands, high energy density lithium secondary batteries have been developed. Recently, ultra-thin and lightweight secondary batteries using containers made of aluminum laminate film have also been developed and commercialized. .

  In a secondary battery using this aluminum laminate film container, if a carbon material that occludes / releases lithium ions is used for the negative electrode, the amount of change in battery thickness due to volume expansion / contraction of the negative electrode accompanying charge / discharge increases, The battery is swung or the space between the electrodes is expanded, the internal resistance is increased, and the battery characteristics are deteriorated.

  As a material system that can avoid such a problem, Patent Document 1 proposes a battery that uses lithium titanate as a negative electrode active material. Lithium titanate has almost no volume change associated with charging and discharging, and as a result, the change in battery thickness is extremely small. By using this compound for the negative electrode active material, the above-described problems are solved.

Lithium titanate undergoes a lithium occlusion / release reaction at about 1.55 V. Therefore, for example, when LiCoO ₂ is used as the positive electrode active material, the battery voltage is 2.3 V. This potential is lower than the battery voltage of 3.8 V of the carbon negative electrode / LiCoO ₂ positive electrode, which is a lithium ion secondary battery that is widely commercialized, leading to a decrease in energy density.
JP-A-9-199179

  An object of the present invention is to provide a nonaqueous electrolyte battery with improved energy density.

  A non-aqueous electrolyte battery according to the present invention includes a negative electrode including an active material that has a crystal structure in which a space group is Cmca and absorbs and releases lithium ions, a positive electrode, and a non-aqueous electrolyte. It is.

  According to the present invention, a nonaqueous electrolyte battery with improved energy density can be provided.

  In the present invention, a metal oxide that has a crystal structure with a space group of Cmca and that absorbs and releases lithium ions is used as the negative electrode active material. In addition, the occlusion and release reaction of lithium can proceed at a base potential lower than that of lithium titanate, the average discharge voltage can be increased, and the energy density can be improved. Moreover, the nonaqueous electrolyte secondary battery provided with the negative electrode containing this negative electrode active material can implement | achieve the charge / discharge cycle life equivalent to or more than the case where lithium titanate is used.

When this negative electrode active material has a composition represented by the following formula (1), not only can the energy density and the charge / discharge cycle life be improved, but also the average discharge voltage when combined with a positive electrode containing LiCoO ₂ is increased. Since the voltage can be in the range of 2.4 to 2.6 V, compatibility with existing dry batteries and nickel hydride secondary battery 2 series can be provided.

Li _{2 + x} AT ₆ O ₁₄ (1)
However, A is at least one element selected from the group consisting of Na, K, Mg, Ca, Ba and Sr, and T is Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Zr, X is 0 ≦ x ≦ 5 with at least one element selected from the group consisting of Nb, Mo, Hf, Ta, W, B, Al, Ga and In.

When lithium titanate such as Li ₄ Ti ₁₅ O ₁₂ is used as the negative electrode active material, for example, when combined with a positive electrode containing LiCoO ₂ , the lithium storage / release potential of lithium titanate is 1.55 V, so the battery voltage is 2 .3V and energy density is reduced.

When the negative electrode active material represented by the formula (1) described above is used, the capacity per unit weight is equivalent to that of lithium titanate, but the lithium adsorption / desorption reaction is 1.3 to 1.4 V (vs. Li). / Li ⁺ ). When combined with a positive electrode containing LiCoO ₂ , the battery voltage is 2.45 to 2.55 V, and the energy density can be increased by about 10%. In addition, this voltage can be compatible with an existing dry battery or a series of nickel metal hydride batteries 2 and has a very high commercial value. As described above, the negative electrode active material having a crystal structure in which the space group is Cmca as a factor that shifts the lithium adsorption / desorption reaction potential to the base side as compared with lithium titanate. It is conceivable that the emission site is different from that of lithium titanate.

  The element T constituting the negative electrode active material represented by the formula (1) described above preferably contains Ti as a main component from the viewpoint of cycle life. By using Ti as the main component, the stability of the crystal structure can be increased, so that a good cycle life can be realized.

  The negative electrode active material having a crystal structure in which the space group is Cmca has a composition represented by the following formula (2), thereby realizing a high energy density and an excellent charge / discharge cycle life, and a large current characteristic (load characteristic). Can be improved.

Li _{2 + x} ATi _{6- y My} O ₁₄ (2)
However, A is at least one element selected from the group consisting of Na, K, Mg, Ca, Ba and Sr, and M is V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Zr, Nb, At least one element selected from the group consisting of Mo, Hf, Ta, W, B, Al, Ga and In, where x is 0 ≦ x ≦ 5 and y is 0 <y <6.

  The reason why the atomic ratio y of the element M is limited to the above range is that, if the element M is added, the large current characteristic (load characteristic) can be improved, but the discharge capacity may be lowered as the atomic ratio y increases. Because there is. In order to achieve both good cycle characteristics of Ti and large current characteristics due to the addition of M element, y is more preferably 0.001 ≦ y ≦ 3, and more preferably 0.01 ≦ y ≦ 1. is there.

  The present invention can be applied not only to secondary batteries but also to primary batteries. Hereinafter, an embodiment of the nonaqueous electrolyte battery according to the present invention will be described in detail. First, the positive electrode, the negative electrode, and the nonaqueous electrolyte 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.

  The positive electrode current collector can be formed of, for example, 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., _{Li x Mn 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 ), iron sulfate (Fe ₂ (SO ₄ ) ₃ ), vanadium oxide (for example, V ₂ O ₅ ), and the like. 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 (Li _x Mn ₂ O ₄ ), lithium nickel composite oxide (Li _x NiO ₂ ), and lithium cobalt composite oxide (Li _x CoO ₂ ), lithium nickel cobalt composite oxide (LiNi _1-y Co _y O ₂ ), spinel type lithium manganese nickel composite oxide (Li _x Mn _{2 -y} Ni _y O ₄ ), lithium manganese cobalt composite oxide ( _{Li x Mn y Co 1-y} O 2), lithium iron phosphate (Li _x FePO ₄₎ may be mentioned (Note, x, y is preferably in the range of 0-1.)
Examples of the binder include polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVdF), and fluorine-based rubber.

  The positive electrode layer may contain a conductive agent. Examples of the conductive agent include acetylene black, carbon black, and graphite.

  The mixing 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.

2) Negative electrode The negative electrode includes a negative electrode current collector and a negative electrode layer that is supported on one or both surfaces of the current collector and contains a negative electrode active material.

  The negative electrode active material includes those having a crystal structure in which lithium ions are occluded / released and the space group is Cmca.

Examples of the composition of the negative electrode active material having a crystal structure in which the space group is Cmca include Sr ₄ Mn ₃ O ₁₀ and CuLaO _{4 in} addition to those represented by the above formulas (1) and (2).

  In the compositions represented by the above-described formulas (1) and (2), the atomic ratio of lithium varies as lithium is occluded and released by charging and discharging, and x can take up to 0 ≦ x ≦ 5. The reason why x is 5 or less is that x = 5 when the material having this structure has entered all the sites where lithium ions can enter.

  Among the elements A, alkaline earth metals (Mg, Ca, Ba, Sr) are preferable in the compositions represented by the above-described formulas (1) and (2). When an alkali metal such as Na or K is used, the stability of the crystal structure is lowered, so that an exchange reaction with lithium metal is likely to occur, which may cause deterioration in characteristics and a reduction in discharge capacity. .

Of the compositions represented by the above formula (1), Li _{2 + x} MgT ₆ O ₁₄ and Li _{2 + x} CaT ₆ O ₁₄ are preferable from the viewpoint of energy density per substance weight. By setting the element A to Mg or Ca, the capacity per unit weight can be increased.

  As the negative electrode active material, only a material having a crystal structure whose space group is Cmca may be used, or another active material that absorbs and releases lithium may be used in combination. Examples of other active materials include carbonaceous materials, alloys, oxides, nitrides, and carbides.

  The average particle diameter of the negative electrode active material is preferably 0.1 to 10 μm. This is due to the reason explained below. If the average particle size is less than 0.1 μm, it is necessary to increase the amount of the conductive agent in order to ensure the current collecting performance, and the effective negative electrode capacity may be reduced. In addition, workability in manufacturing may be significantly reduced. On the other hand, when the average particle diameter exceeds 10 μm, the current collecting performance may be deteriorated. A more preferable range of the average particle diameter is 0.5 to 5 μm.

BET specific surface area of the negative electrode active material is preferably in the range of 5m ² / g~100m ² / g. This is due to the reason explained below. If the specific surface area is less than 5 m ² / g, the current collecting performance may be lowered. On the other hand, if the specific surface area exceeds 100 m ² / g, it is necessary to increase the amount of the conductive agent, which may reduce the effective negative electrode capacity. In addition, workability in manufacturing may be significantly reduced.

  Examples of the material for forming the negative electrode current collector include aluminum and aluminum alloys.

  The negative electrode is prepared by suspending the negative electrode active material, the conductive agent and the binder in a suitable solvent, and applying this suspension to a current collector such as an aluminum foil, drying and pressing to form a strip electrode. Is done.

  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 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. If the amount of the conductive agent is less than 2% by weight, there is a possibility that the current collecting property is lacking and the large current characteristic is deteriorated. In addition, if the amount of the binder is less than 2% by weight, the binding performance between the negative electrode layer and the current collector is lacking, and the cycle performance may be deteriorated. 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.

3) Non-aqueous electrolyte As the non-aqueous electrolyte, for example, a non-aqueous electrolyte in which an electrolyte is dissolved in an organic solvent, a lithium salt and a room temperature molten salt, or the like can be used.

  First, the nonaqueous electrolytic solution will be described.

Examples of the electrolyte include lithium perchlorate (LiClO ₄ ), lithium hexafluorophosphate (LiPF ₆ ), lithium tetrafluoroborate (LiBF ₄ ), lithium hexafluoroarsenide (LiAsF ₆ ), and trifluoro Examples thereof include lithium salts such as lithium metasulfonate (LiCF ₃ SO ₃ ) and bistrifluoromethylsulfonylimitolithium [LiN (CF ₃ SO ₂ ) ₂ ]. The electrolyte is preferably dissolved in the range of 0.5 to 2 mol / L with respect to the organic solvent.

  Examples of the organic solvent include cyclic carbonates such as ethylene carbonate (EC), propylene carbonate (PC), and vinylene carbonate (VC), dimethyl carbonate (DMC), methyl ethyl carbonate (MEC), and diethyl carbonate (DEC). Examples include chain carbonates, cyclic ethers such as tetrahydrofuran (THF), 2-methyltetrahydrofuran (2MeTHF), chain ethers such as dimethoxyethane (DME), γ-butyrolactone (BL), acetonitrile (AN), sulfolane (SL), and the like. be able to. These organic solvents can be used alone or in the form of a mixture of two or more.

  Next, a nonaqueous electrolyte containing a lithium salt and a room temperature molten salt will be described.

  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 the lithium salt, a lithium salt having a wide potential window, which is generally used for lithium secondary 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 content of the lithium salt in the nonaqueous electrolyte is desirably 0.1 to 3 mol / L. This is due to the reason explained below. If the content of the lithium salt is less than 0.1 mol / L, the ion conductivity of the non-aqueous electrolyte is lowered and high high current / low temperature discharge characteristics may not be obtained. On the other hand, when the content of the lithium salt exceeds 3 mol / L, the melting point of the non-aqueous electrolyte is increased and it may be difficult to maintain a liquid state at room temperature. A more preferable range of the lithium salt content is 1 to 2 mol / L.

As the room temperature molten salt, for example, a salt having a quaternary ammonium organic cation having a skeleton represented by the formula (A) of Chemical Formula 1 or an imidazolium cation having a skeleton represented by the Formula (B) of Chemical Formula 2 Is.

However, in the formula (B), R1 and R2 are each C _n H _{2n + 1} (n = 1 to 6), and may be the same or different from each other, 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 (A) include imidazolium ions such as dialkylimidazolium and trialkylimidazolium, tetraalkylammonium ions, alkylpyridinium ions, pyrazolium ions, pyrrolidinium ions, pipettes. Examples include ridinium ions. In particular, an imidazolium cation having a skeleton represented by the formula (B) 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.

  The imidazolium cation having a skeleton represented by the formula (B) will be described. Examples of the dialkylimidazolium ion include 1,3-dimethylimidazolium ion, 1-ethyl-3-methylimidazolium ion, 1-methyl-3-ethylimidazolium ion, 1-methyl-3-butylimidazolium ion, 1 -Butyl-3-methylimidazolium ion and the like. On the other hand, as the trialkylimidazolium ion, 1,2,3-trimethylimidazolium ion, 1,2-dimethyl-3-ethylimidazolium ion, 1, Examples thereof include, but are not limited to, 2-dimethyl-3-propylimidazolium ion and 1-butyl-2,3-dimethylimidazolium ion.

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

  A separator can be disposed between the positive electrode and the negative electrode.

  For example, 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.

  A metal container or a laminate film container can be used for the container 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 0.2 mm or less.

  Examples of the laminate film include a multilayer film in which a metal foil is coated 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.

  An example of the nonaqueous electrolyte secondary battery according to the present invention is shown in FIG.

  As shown in FIG. 1, the electrode group 1 has a structure in which a positive electrode 2 and a negative electrode 3 are wound into a flat shape with a separator 4 interposed therebetween. The electrode group 1 is manufactured by winding a positive electrode 2 and a negative electrode 3 in a flat shape with a separator 4 interposed therebetween, and then applying a heat press. The positive electrode 2, the negative electrode 3, and the separator 4 in the electrode group 1 may be integrated by a polymer having adhesiveness. The strip-like positive electrode terminal 5 is electrically connected to the positive electrode 2. On the other hand, the strip-like negative electrode terminal 6 is electrically connected to the negative electrode 3. The electrode group 1 is housed in a laminated film container 7 with the ends of the positive electrode terminal 5 and the negative electrode terminal 6 protruding from the container 7. The laminated film container 7 is sealed by heat sealing.

[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
<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. The slurry was applied to both sides of a current collector made of 15 μm aluminum foil, dried, and pressed to prepare a positive electrode having an electrode density of 3.0 g / cm ³ .

<Production of negative electrode>
Li ₂ MgTi ₆ O ₁₄ having a crystal structure with a space group of Cmca as a negative electrode active material, acetylene black having an average particle diameter of 1 μm and a specific surface area of 8 m ² / g as a conductive material, and polyfluoride Vinylidene (PVdF) was added to an N-methylpyrrolidone (NMP) solution in a weight ratio of 90: 5: 5 and mixed, and the resulting slurry was applied to an aluminum foil having a thickness of 15 μm and dried. Then, the negative electrode was produced by pressing.

  The crystal structure of the lithium-titanium-containing composite oxide that is the negative electrode active material was identified by powder X-ray diffraction measurement.

<Production of electrode group>
The positive electrode, a separator made of a polyethylene porous film with a thickness of 25 μm, the negative electrode, and the separator were laminated in this order, and then 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>
A liquid nonaqueous electrolyte is prepared by dissolving 1.5 mol / L of lithium tetrafluoroborate (LiBF ₄ ) as an electrolyte in a mixed solvent (volume ratio 25:75) of ethylene carbonate (EC) and γ-butyrolactone (BL). (Nonaqueous electrolyte) was prepared.

  After injecting the liquid non-aqueous electrolyte into the laminate 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 in Example 1 was manufactured except that a lithium-titanium-containing composite oxide having a crystal structure in which the space group having the composition shown in Table 1 below was Cmca was used as the negative electrode active material. .

(Comparative Example 1)
Example 1 except that lithium titanate having a spinel structure having the composition shown in Table 1 below and belonging to the space group Fd3-m (3- indicates that-is present on 3) is used as the negative electrode active material. A non-aqueous electrolyte secondary battery having the same configuration as in Example 1 was produced.

For the secondary batteries of Examples 1 to 7 and Comparative Example 1, initial charge / discharge was performed at a current of 0.2 C, and the energy density of the battery was calculated from the average operating voltage of the battery. Subsequently, the 1C / 1C charge / discharge cycle was repeated 500 times for the battery whose capacity was confirmed, and the battery capacity after 500 cycles was compared with the initial capacity. The results are summarized in Table 1.

  As is clear from Table 1, the batteries of Examples 1 to 7 including the negative electrode including a lithium-containing composite oxide having a crystal structure whose space group is Cmca are comparative examples using lithium titanate as a negative electrode active material. It was found that the battery voltage was higher and the energy density was higher than that of the first battery.

(Example 8)
A non-aqueous electrolyte secondary battery having the same configuration as that of Example 1 was prepared except that Li ₂ BaTi _6-y Al _y O ₁₄ having a crystal structure with a space group of Cmca was used as the negative electrode active material. At this time, seven types of nonaqueous electrolyte secondary batteries were prepared using seven types of negative electrode active materials in which the value of y was adjusted to 0, 0.001, 0.01, 0.1, 1, 3, and 5. did. The composition of the seven types of negative electrode active materials is shown in Table 2 below.

The capacity of the seven types of batteries produced in Example 8 was confirmed with a 0.2 C current and a 2 C current, and an energy density at a 0.2 C discharge and a discharge capacity ratio of 2 C / 0.2 C were obtained. Subsequently, the 1C / 1C charge / discharge cycle was repeated 500 times for the battery whose capacity was confirmed, and the battery capacity after 500 cycles was compared with the initial capacity. The results are summarized in Table 2. Further, the discharge capacity ratio of 2C / 0.2C was also measured for the battery of Comparative Example 1, and the results are also shown in Table 2 below.

As is apparent from Table 2, it was found that the large current characteristics (load characteristics) can be enhanced by adding the third element to Li ₂ BaTi ₆ O ₁₄ having a crystal structure in which the space group is Cmca.

(Examples 9 to 21)
A nonaqueous electrolyte secondary having the same structure as described in Example 1 except that a negative electrode active material represented by the composition shown in Table 3 below and having a crystal structure with a space group of Cmca is used. A battery was produced.

About the obtained secondary battery of Examples 9-21, capacity | capacitance confirmation was carried out by 0.2 C electric current and 2 C electric current, the discharge capacity ratio of 2 C / 0.2 C was calculated | required, and the result is shown in following Table 3.

  From the results in Table 3, it is confirmed that a high current characteristic can be obtained by using the negative electrode active material having a crystal structure in which the space group is Cmca and the composition represented by (2) described above. I was able to.

(Example 22)
A non-aqueous electrolyte secondary battery having the same configuration as described in Example 1 was prepared except that Sr ₄ Mn ₃ O ₁₀ having a crystal structure with a space group of Cmca was used as the negative electrode active material. The obtained secondary battery of Example 22 was initially charged and discharged at a current of 0.2 C, and the energy density of the battery was calculated from the average operating voltage of the battery, which was 140 Wh / L, which was higher than that of Comparative Example 1.

  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 partial notch perspective view which shows the thin nonaqueous electrolyte secondary battery which is one Embodiment of the nonaqueous electrolyte battery which concerns on this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Electrode group, 2 ... Positive electrode, 3 ... Negative electrode, 4 ... Separator, 5 ... Positive electrode terminal, 6 ... Negative electrode terminal, 7 ... Container.

Claims (5)

  A nonaqueous electrolyte battery comprising: a negative electrode having an active material that has a crystal structure in which a space group is Cmca, and occludes / releases lithium ions; a positive electrode; and a nonaqueous electrolyte. The non-aqueous electrolyte battery according to claim 1, wherein the active material has a composition represented by the following formula (1).
Li _{2 + x} AT ₆ O ₁₄ (1)
However, A is at least one element selected from the group consisting of Na, K, Mg, Ca, Ba and Sr, and T is Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Zr, X is 0 ≦ x ≦ 5 with at least one element selected from the group consisting of Nb, Mo, Hf, Ta, W, B, Al, Ga and In. The non-aqueous electrolyte battery according to claim 1, wherein the active material has a composition represented by the following formula (2).
Li _{2 + x} ATi _{6- y My} O ₁₄ (2)
However, A is at least one element selected from the group consisting of Na, K, Mg, Ca, Ba and Sr, and M is V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Zr, Nb, At least one element selected from the group consisting of Mo, Hf, Ta, W, B, Al, Ga and In, where x is 0 ≦ x ≦ 5 and y is 0 <y <6.   The non-aqueous electrolyte battery according to claim 1, wherein the active material has an average particle diameter of 0.1 μm to 10 μm. The active material is a non-aqueous electrolyte battery according to any one of the preceding claims, characterized in that the specific surface area of 5m ² / g~100m ² / g.

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