JP2014067731A - Nonaqueous electrolyte battery, and battery pack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a nonaqueous electrolyte battery having a high capacity and heavy current characteristics.SOLUTION: This nonaqueous electrolyte battery includes a jacket material, a positive electrode housed in the jacket material, and a negative electrode spacially separated from the positive electrode and housed in the jacket material while including an active material containing a titanium composite oxide, a nonaqueous electrolyte housed in the jacket material. The titanium composite oxide contains a monoclinic β-type titanium complex oxide as a main phase, and when integrated intensity of the monoclinic β-type titanium complex oxide at its main peak by a wide-angle X-ray diffraction method using CuKα ray as an X-ray source is set to be 100, the relative value of the integrated intensity at a main peak appeared at 2θ=25.1-25.5° attributed to at least one auxiliary phase selected from an anatase type TiOand HTiOis not more than 30, and a crystallite diameter calculated from the main peak of the monoclinic β type titanium complex oxide obtained by the wide-angle X-ray diffraction method is not less than 5 nm.

Description

  The present embodiment relates to a battery active material, a non-aqueous electrolyte battery, and a battery pack.

In recent years, titanium oxide having a monoclinic β-type structure (referred to as TiO ₂ (B)) has attracted attention as an active material for nonaqueous electrolyte batteries (see Patent Documents 1 to 3). Conventionally, spinel-type lithium titanate (Li ₄ Ti ₅ O ₁₂ ) that has been practically used has three lithium ions that can be inserted and removed per unit chemical formula. For this reason, the number of lithium ions that can be inserted / removed per titanium ion was 3/5, and 0.6 was the theoretical maximum. On the other hand, in TiO ₂ (B), the maximum number of lithium ions that can be inserted / removed per titanium ion is 1.0. Therefore, the theoretical capacity is as high as about 335 mAh / g.

However, the practical electrode capacity of TiO ₂ (B) is about 170 to 200 mAh / g as disclosed in Patent Document 1 or Patent Document 2, which is significantly lower than the theoretical capacity. This is because, despite the fact that there are many sites that can serve as Li hosts in the crystal structure of TiO ₂ (B), the diffusibility of Li ions in the solid is low, so that there are few effective mobile Li ions. Conceivable.

JP 2008-34368 A JP 2008-117625 A WO 2009/028553 A1

The present embodiment includes a battery active material containing TiO ₂ (B) with enhanced lithium ion conductivity, a non-aqueous electrolyte battery containing this active material as a negative electrode active material, and having high capacity and excellent large current characteristics, And it aims at providing the battery pack provided with two or more of this nonaqueous electrolyte battery.

According to the first aspect of the present embodiment, an active material for a non-aqueous electrolyte battery containing titanium oxide or a titanium composite oxide,
The titanium oxide or titanium composite oxide contains a monoclinic β-type titanium composite oxide as a main phase, and the monoclinic β-type titanium composite by a wide angle X-ray diffraction method using CuKα rays as an X-ray source. When the integrated intensity of the main peak of the oxide is 100, the main appearing at 2θ = 25.1 to 25.5 ° belonging to at least one subphase selected from anatase TiO ₂ and H ₂ Ti ₈ O ₁₇ The relative value of the integrated intensity of the peak is 30 or less,
The titanium oxide or titanium composite oxide is a nonaqueous electrolyte battery having a crystallite diameter of 5 nm or more calculated from a main peak of the monoclinic β-type titanium composite oxide obtained by the wide-angle X-ray diffraction method An active material is provided.

According to the second aspect of the present embodiment, an exterior material; a positive electrode housed in the exterior material;
A negative electrode containing an active material that is spatially separated from the positive electrode and contains titanium oxide or a titanium composite oxide; and a nonaqueous electrolyte contained in the outer material. The titanium oxide or the titanium composite oxide contains a monoclinic β-type titanium composite oxide as a main phase, and the monoclinic β-type titanium by a wide angle X-ray diffraction method using CuKα rays as an X-ray source. When the integrated intensity of the main peak of the composite oxide is 100, it appears at 2θ = 25.1 to 25.5 ° belonging to at least one subphase selected from anatase TiO ₂ and H ₂ Ti ₈ O _17. The relative value of the integral intensity of the main peak is 30 or less, and the titanium oxide or the titanium composite oxide is calculated from the main peak of the monoclinic β-type titanium composite oxide obtained by the wide angle X-ray diffraction method. Yui Nonaqueous electrolyte battery child diameter of 5nm or more is provided.

  According to the third aspect of the present embodiment, there is provided a battery pack comprising a plurality of the non-aqueous electrolyte batteries of the second aspect, wherein each battery is electrically connected in series, in parallel or in series and in parallel.

It is sectional drawing which shows the flat type nonaqueous electrolyte battery which concerns on embodiment. It is an expanded sectional view of the A section of FIG. It is a disassembled perspective view which shows the battery pack which concerns on embodiment. It is a block diagram of the battery pack of FIG. 2 is a diagram showing an X-ray diffraction pattern of a titanium composite oxide of Example 1. FIG. 4 is a diagram showing an X-ray diffraction pattern of a titanium composite oxide of Comparative Example 1. FIG. It is a figure which shows the X-ray-diffraction pattern of the titanium complex oxide of Example 7. It is a schematic diagram which shows the crystal structure of a monoclinic system type β-type titanium oxide (TiO ₂ (B)).

  Hereinafter, the battery active material, the nonaqueous electrolyte battery, and the battery pack according to the present embodiment will be described in detail.

The battery active material according to the embodiment includes a titanium composite oxide. The titanium composite oxide contains a monoclinic β-type titanium composite oxide as a main phase, and the main peak of the monoclinic β-type titanium composite oxide by a wide angle X-ray diffraction method using CuKα rays as an X-ray source. The integrated intensity of the main peak appearing at 2θ = 25.1 to 25.5 ° attributed to at least one subphase selected from anatase TiO ₂ and H ₂ Ti ₈ O ₁₇ It has a structure with a relative value of 30 or less. That is, the integrated intensity I ₁ of the titanium composite oxide is monoclinic β-type titanium composite _oxide, the integrated intensity of the at least one secondary phase I _2, and then, when the I ₁ to 100, I for I ₁ The relative value of ₂ has a structure of 30 or less. At this time, the main peak of anatase TiO ₂ is detected at 2θ = about 25.4 °, and the main peak of H ₂ Ti ₈ O ₁₇ is detected at 2θ = about 25.3 °. In the titanium composite oxide, the crystallite diameter calculated from the main peak of the monoclinic β-type titanium composite oxide obtained by the wide-angle X-ray diffraction method is 5 nm or more.

  The wide angle X-ray diffraction method will be described below.

  The powder (sample) obtained by pulverizing the titanium composite oxide is filled into a 0.2 mm deep holder of a glass sample plate. Using a glass plate from the outside, the sample surface filled in the glass sample plate is smoothed by sufficiently pressing with a finger. At this time, care is taken so that the sample is sufficiently filled in the holder portion, and care is taken so as not to cause insufficient filling (cracking, voids) of the sample. The sample amount is filled so as to be equal to the depth (0.2 mm) of the glass holder, and care is taken so that unevenness does not occur from the reference surface of the glass holder due to excessive or insufficient filling amount.

  Moreover, the following method is more preferable in order to eliminate the shift | offset | difference of a diffraction-beam peak position and the change of intensity ratio by the filling method to a glass sample plate. That is, by applying a pressure of about 250 MPa to the sample for 15 minutes, a green compact pellet having a diameter of 10 mm and a thickness of about 2 mm is produced, and the pellet surface is measured.

  The measurement can be performed, for example, under the following conditions.

<Measurement method>
The sample was packed in a standard glass holder having a diameter of 25 mm, and measurement was performed by wide-angle X-ray diffraction. The measuring equipment and conditions are shown below.

(1) X-ray diffractometer: Bruker AXS; D8 ADVANCE (encapsulated tube type)
X-ray source: CuKα ray (using Ni filter)
Output: 40kV, 40mA
Slit system: Div. Slit; 0.3 °
Detector: LynxEye (High-speed detector)
(2) Scan method: 2θ / θ continuous scan (3) Measurement range (2θ): 5 to 100 °
(4) Step width (2θ): 0.01712 °
(5) Counting time: 1 second / step.

The crystallite diameter (crystallite size) of the titanium composite oxide can be calculated by using the Scherrer equation shown below for the half width of the main peak of TiO ₂ (B) obtained by the wide-angle X-ray diffraction method.

  Here, K = 0.9, λ (= 0.15406 nm), βe: half-value width of the diffraction peak, and βo: correction value (0.07 °) of the half-value width.

  Further, the integral intensity can be obtained as follows. A smoothing process and a background removal process are continuously performed on the X-ray diffraction profile after the measurement. The pseudo-Voigt function was applied to the obtained profile to perform peak separation, and the Kα1 peak area was defined as the integrated intensity.

The crystal structure of monoclinic titanium dioxide is denoted as TiO ₂ (B). The crystal structure represented by TiO ₂ (B) mainly belongs to the space group C2 / m, and shows a tunnel structure as illustrated in FIG. The detailed crystal structure of TiO ₂ (B) is described in R. Marchand, L. Brohan, M. Tournoux, Material Research.

As shown in FIG. 8, the crystal structure represented by TiO ₂ (B) has a structure in which titanium ions 53 and oxide ions 52 constitute a skeleton structure portion 51a, and the skeleton structure portions 51a are alternately arranged. . A gap portion 51b is formed between the skeleton structure portions 51a. This void portion 51b can serve as a host site for intercalation (insertion) of different atomic species. TiO ₂ (B) is also said to have host sites capable of occluding and releasing heteroatomic species on the crystal surface. TiO ₂ (B) can reversibly occlude and release lithium ions when lithium ions are inserted into and desorbed from these host sites.

When lithium ions are inserted into the void portion 51b, Ti ⁴⁺ constituting the skeleton is reduced to Ti ³⁺ , thereby maintaining the electrical neutrality of the crystal. Since TiO ₂ (B) has one Ti ⁴⁺ per chemical formula, it is theoretically possible to insert a maximum of one lithium ion between the layers. For this reason, the titanium oxide compound having a TiO ₂ (B) crystal structure can be represented by the general formula Li _x TiO ₂ (0 ≦ x ≦ 1). In this case, a theoretical capacity of 335 mAh / g, which is nearly twice that of the titanium dioxide described in Patent Documents 1 and 2, is obtained.

However, since TiO ₂ (B) is a low-temperature metastable phase existing at a temperature lower than about 500 ° C., at least one subphase selected from anatase TiO ₂ and H ₂ Ti ₈ O ₁₇ is mixed as an impurity phase during synthesis. It becomes easy to do. Since the impurity phase inhibits the diffusion of lithium ions, the ionic conductivity of TiO ₂ (B) lithium is lowered. As a result, it was difficult for the conventional TiO ₂ (B) to stably extract a high capacity of 240 mAh / g or more.

TiO ₂ (B) is a factor different from the presence of the impurity phase, and has a low lithium ion diffusion rate and a relatively low lithium ion conductivity. TiO ₂ (B) is considered to have a lithium ion conductivity lower by about two orders of magnitude or more than, for example, a lithium cobalt composite oxide used as a positive electrode active material. For this reason, a nonaqueous electrolyte battery in which TiO ₂ (B) is combined as a negative electrode active material and lithium cobalt composite oxide is used as a positive electrode active material has a TiO ₂ (B ), The high current characteristics are deteriorated.

  The diffusion rate of lithium ions means a combination of intragranular diffusion and grain boundary diffusion of the active material.

The battery active material according to the embodiment includes a monoclinic β-type titanium composite oxide (TiO ₂ (B)) as a main phase, and the TiO ₂ by the wide-angle X-ray diffraction method using CuKα rays as an X-ray source. When the integrated intensity of the main peak of (B) is 100, at least one subphase selected from anatase TiO ₂ and H ₂ Ti ₈ O ₁₇ , that is, 2θ = 25.1 to 25.25 belonging to the impurity phase. It includes a titanium composite oxide having a structure in which the relative value of the integrated intensity of the peak appearing at 5 ° is 30 or less. Such a titanium composite oxide can reduce the amount of the impurity phase that inhibits the diffusion of lithium ions, or is substantially zero, so that the ion conductivity of lithium can be improved. As a result, it becomes possible to draw out a high electric capacity specific to TiO ₂ (B).

The titanium composite oxide has a crystallite diameter of 5 nm or more calculated from the main peak of TiO ₂ (B) obtained by the wide-angle X-ray diffraction method, that is, a large crystallite diameter. As a result, the diffusion rate of lithium ions in the titanium composite oxide is increased, and the ion conductivity of lithium can be improved. Therefore, when the titanium composite oxide is combined as a negative electrode active material and the lithium cobalt composite oxide is combined as a positive electrode active material and lithium ions are adsorbed / desorbed between the positive electrode and the negative electrode, a high diffusion rate of lithium ions is obtained. The titanium composite oxide possessed can relax the diffusion rate-determining rate of lithium ions in the negative electrode relative to the positive electrode, and can improve the large current characteristics.

  By setting the crystallite diameter of the titanium composite oxide to 5 nm or more as described above, the ion conductivity and large current characteristics of the titanium composite oxide can be improved. The crystallite diameter of the titanium composite oxide is more preferably 20 nm or more. The upper limit of the crystallite diameter of the titanium composite oxide is 300 nm.

When the integrated intensity of the main peak of TiO ₂ (B) by wide-angle X-ray diffraction method is 100, it is attributed to at least one subphase selected from anatase TiO ₂ and H ₂ Ti ₈ O ₁₇ , that is, an impurity phase. When the relative value of the integrated intensity of the peak appearing at 2θ = 25.1 to 25.5 ° is 30 or less, the diffusion rate of lithium ions in the titanium composite oxide can be improved, and the ion conductivity and large current can be improved. The characteristics can be improved. The relative value of the integrated intensity of the peak appearing at 2θ = 25.1 to 25.5 ° attributed to a more preferable subphase is 10 or less, more preferably 3 or less. It is preferable that the titanium composite oxide does not include an impurity phase and has a structure that is substantially composed of TiO ₂ (B) that is a main phase. Therefore, the titanium composite oxide includes a state where the impurity phase is below the detection limit, that is, a state where the impurity phase is zero.

  The primary particle diameter of the titanium composite oxide is preferably 30 nm or more and 3 μm or less. When the primary particle diameter is 30 nm or more, it becomes easy to handle in industrial production. When the primary particle diameter is 3 μm or less, the diffusion distance of lithium ions in the solid is shortened, and the large current performance can be improved. A more preferable upper limit of the primary particle diameter is 1 μm.

The specific surface area of the titanium composite oxide is preferably 5 m ² / g or more and 50 m ² / g or less. When the specific surface area is 5 m ² / g or more, sufficient lithium ion storage / release sites can be secured. When the specific surface area is 50 m ² / g or less, it becomes easy to handle in industrial production.

The titanium composite oxide contains at least one element selected from P and B, and the content of at least one element is 0.01 wt% or more in total with respect to the total amount of the titanium composite oxide and at least one element. It is preferable that it is below wt%. The titanium composite oxide containing at least one element is preferably in the form of particles, and at least one element is preferably present as an oxide in or on the particles of the titanium composite oxide. Such a titanium composite oxide containing at least one element selected from P and B can further reduce the contamination of the impurity phase, increase the crystallinity, and increase the crystallite diameter. As a result, a titanium composite oxide that can stably extract a capacity of 240 mAh / g or more can be obtained. When the content of at least one element is less than 0.01% by weight, the effect of increasing crystallinity is reduced. If the content of at least one element exceeds 3% by weight, the amount of impurity phase of P ₂ O ₅ and B ₂ O ₃ increases, which may reduce the electric capacity. Of the at least one element, P is preferable because the above-described effect is higher than that of B.

  The content of at least one element selected from P and B can be measured by ICP emission spectroscopy. Measurement of the content of the element by ICP emission spectroscopy can be performed by the following method, for example. The battery is disassembled in a discharged state, an electrode (for example, a negative electrode) is taken out, and the negative electrode layer is deactivated in water. Thereafter, the titanium composite oxide in the negative electrode layer is extracted. The extraction treatment can be performed, for example, by removing the conductive agent and binder in the negative electrode layer by heat treatment in the atmosphere. After measuring the extracted titanium composite oxide in a container, it is melted by acid or alkali to obtain a measurement solution. The measurement solution is subjected to ICP emission spectroscopy with a measuring device (for example, SPS-1500V, manufactured by SII Nano Technology) to measure the content of the element.

  The titanium composite oxide allows to contain 1000 ppm by weight or less of impurities inevitable in production other than at least one element selected from P and B.

  Next, the manufacturing method of the active material for batteries which concerns on embodiment is demonstrated.

First, an alkali titanate compound such as Na ₂ Ti ₃ O ₇ , K ₂ Ti ₄ O ₉ , or Cs ₂ Ti ₅ O ₁₂ is prepared as a starting material. The alkali titanate compound can be synthesized by a general solid phase reaction method by mixing a substance containing Ti and a substance containing an alkali element such as Na, K, or Cs at a predetermined ratio. The method for synthesizing the starting material is not limited to any method or crystal shape. Note that potassium titanate of K ₂ Ti ₄ O ₉ can be synthesized by, for example, a flux method.

  The starting material is washed thoroughly with pure water to remove impurities from the alkali titanate compound, and then acid-treated to exchange alkali cations for protons. Sodium ion, potassium ion, and cesium ion in sodium titanate, potassium titanate, and cesium titanate can be exchanged with protons without destroying the crystal structure. Proton exchange by acid treatment is performed, for example, by adding 1 M hydrochloric acid to the starting material and stirring. The acid treatment is desirably performed until the proton exchange is sufficiently completed. During proton exchange, an alkaline solution or an acid solution may be added to the solution to adjust the pH. After the proton exchange is completed, it is washed again with pure water.

The starting material is preferably pulverized in advance with a ball mill before proton exchange. This grinding can perform a smooth proton exchange. The pulverization conditions can be performed by using zirconia balls having a diameter of about 10 to 15 mm per 100 cm ² container and rotating the zirconia balls for about 1 to 3 hours at a rotation speed of 600 to 1000 rpm. The pulverization for 1 hour or less is not preferable because the starting material is not sufficiently pulverized. Further, pulverization for a long time of 3 hours or more is not preferable because the mechanochemical reaction proceeds and the phase is separated into a compound different from the target product.

  By performing proton exchange while applying vibration such as ultrasonic waves, for example, smoother proton exchange can be performed, and a proton exchanger in a suitable state can be obtained.

Next, the product after proton exchange is washed with water and dried to synthesize a proton exchanger as an intermediate product. Subsequently, a titanium composite oxide containing TiO ₂ (B) as a main phase is produced by heat-treating the proton exchanger.

A preferable heating temperature is 250 ° C to 500 ° C. When the heating temperature is less than 250 ° C., the crystallinity is remarkably lowered, the amount of H ₂ Ti ₈ O ₁₇ impurity phase mixed in is increased, and the electric capacity is lowered. On the other hand, when the heating temperature exceeds 500 ° C., the crystallinity is improved and the H ₂ Ti ₈ O ₁₇ phase, which is an impurity phase, decreases, but the amount of anatase-type TiO ₂ phase, which is another impurity phase, increases. There is a possibility that the electric capacity is lowered. A more preferable heating temperature is 300 ° C to 400 ° C.

  The heat treatment time may be about 30 minutes to 24 hours. A more preferable heat treatment time is a temperature of 300 ° C. or higher and 400 ° C. or lower and is 1 hour or longer and 3 hours or shorter.

  A starting material obtained by adding at least one element selected from P and B to the alkali titanate compound may be used. This starting material is synthesized by a general solid phase reaction method by mixing a substance containing at least one element, a substance containing Ti, and a substance containing an alkali element such as Na, K, and Cs in a predetermined ratio. Is possible. The addition amount of at least one element is preferably 0.01% by weight or more and 3% by weight or less in total with respect to the total amount of the obtained titanium composite oxide and the at least one element.

The at least one element functions as a sintering aid during the heat treatment, and an impurity phase such as H ₂ Ti ₈ O ₁₇ is difficult to remain. As a result, it is possible to obtain a titanium composite oxide having a large crystallite diameter and a small impurity phase.

  The battery active material according to the embodiment can be used not only for the negative electrode to be described later but also for the positive electrode. When applied to any of the above, the capacity of the active material is increased, and when the battery is used for a battery, large current characteristics are improved. Contribute to.

  When the battery active material according to the embodiment is used for the positive electrode, the active material of the negative electrode as the counter electrode can be a metallic lithium, a lithium alloy, or a carbon-based material such as graphite or coke.

  Next, the nonaqueous electrolyte battery according to the embodiment will be described.

The nonaqueous electrolyte battery according to the embodiment includes an exterior material, a positive electrode accommodated in the exterior material, and an active material that is spatially separated from the positive electrode in the exterior material, for example, via a separator. Hereinafter, the exterior material, the negative electrode, the positive electrode, the separator, and the nonaqueous electrolyte, which are constituent members of the nonaqueous electrolyte battery, will be described in detail.

1) Exterior material The exterior material is formed from a laminate film having a thickness of 0.5 mm or less. Further, a metal container having a thickness of 1.0 mm or less is used as the exterior material. The metal container is more preferably 0.5 mm or less in thickness.

  Examples of the shape of the exterior material include a flat type (thin type), a square type, a cylindrical type, a coin type, and a button type. Examples of the exterior material include a small battery exterior material loaded on a portable electronic device or the like, and a large battery exterior material loaded on a two-wheeled or four-wheeled vehicle, depending on the battery size.

  As the laminate film, a multilayer film in which a metal layer is interposed between resin layers is used. The metal layer is preferably an aluminum foil or an aluminum alloy foil for weight reduction. For the resin layer, for example, a polymer material such as polypropylene (PP), polyethylene (PE), nylon, polyethylene terephthalate (PET) can be used. The laminate film can be molded into the shape of an exterior material by sealing by heat sealing.

  The metal container is made of aluminum or an aluminum alloy. The aluminum alloy is preferably an alloy containing elements such as magnesium, zinc, and silicon. When transition metals such as iron, copper, nickel and chromium are contained in the alloy, the amount is preferably 100 ppm or less.

2) Negative electrode The negative electrode includes a current collector and a negative electrode layer formed on one or both sides of the current collector and including an active material, a conductive agent, and a binder.

As the active material, the battery active material containing the above-described titanium composite oxide is used. The titanium composite oxide contains a monoclinic β-type titanium composite oxide as a main phase, and the main peak of the monoclinic β-type titanium composite oxide by a wide angle X-ray diffraction method using CuKα rays as an X-ray source. The integrated intensity of the main peak appearing at 2θ = 25.1 to 25.5 ° attributed to at least one subphase selected from anatase TiO ₂ and H ₂ Ti ₈ O ₁₇ The composition has a relative value of 30 or less. In the titanium composite oxide, the crystallite diameter calculated from the main peak of the monoclinic β-type titanium composite oxide obtained by the wide-angle X-ray diffraction method is 5 nm or more.

  As described above, such an active material has a high lithium ion diffusion rate and a high lithium ion conductivity. As a result, a non-aqueous electrolyte battery incorporating a negative electrode including a negative electrode layer containing this active material can improve large current characteristics.

  The conductive agent improves the current collection performance of the active material and suppresses the contact resistance with the current collector. Examples of the conductive agent include acetylene black, carbon black, and graphite.

  The binder can bind the active material and the conductive agent. Examples of the binder include polytetrafluoroethylene (PTFE), polyvinylidene fluoride, fluorine-based rubber, and styrene butadiene rubber.

  The active material, conductive agent and binder in the negative electrode layer are preferably blended in a proportion of 70% to 96% by weight, 2% to 28% by weight and 2% to 28% by weight, respectively. . When the amount of the conductive agent is less than 2% by weight, the current collecting performance of the negative electrode layer is lowered, and the large current characteristics of the nonaqueous electrolyte battery may be lowered. On the other hand, when the amount of the binder is less than 2% by weight, the binding property between the negative electrode layer and the current collector is lowered, and the cycle characteristics may be lowered. On the other hand, the conductive agent and the binder are each preferably 28% by weight or less in order to increase the capacity.

  The current collector is an aluminum foil that is electrochemically stable in a potential range nobler than 1.0 V or an aluminum alloy foil containing elements such as Mg, Ti, Zn, Mn, Fe, Cu, Si. It is preferable.

  The negative electrode is produced, for example, by suspending an active material, a conductive agent, and a binder in a commonly used solvent to prepare a slurry, applying the slurry to a current collector, drying, and then pressing. The The negative electrode may also be produced by forming an active material, a conductive agent and a binder in the form of a pellet to form a negative electrode layer, which is formed on a current collector.

3) Positive electrode The positive electrode includes a current collector and a positive electrode layer formed on one or both sides of the current collector and including an active material, a conductive agent, and a binder.

  As the active material, for example, an oxide, a polymer, or the like can be used.

Examples of the oxide include manganese occluded lithium (MnO ₂ ), iron oxide, copper oxide, nickel oxide and lithium manganese composite oxide (for example, 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 (eg, LiNi _1-y Co _y O ₂ ), lithium manganese cobalt composite oxide (eg, 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 phosphorous oxide having an olipine structure (eg, Li _x FePO ₄ , Li _x Fe _{1 -y) Mn y PO 4, Li x CoPO} 4), using ferrous sulfate _{(Fe 2 (SO 4) 3} ), or vanadium oxides (e.g. V ₂ O ₅₎ be able to. Here, x and y are preferably 0 <x ≦ 1 and 0 ≦ y ≦ 1.

  As the polymer, for example, a conductive polymer material such as polyaniline or polypyrrole, or a disulfide polymer material can be used. Sulfur (S) and carbon fluoride can also be used as the active material.

Preferred active materials include lithium manganese composite oxide (Li _x Mn ₂ O ₄ ), lithium nickel composite oxide (Li _x NiO ₂ ), lithium cobalt composite oxide (Li _x CoO ₂ ), and lithium nickel cobalt having a high positive electrode voltage. complex oxide _{(Li x Ni 1-y coyO} 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 ) or lithium iron phosphate (Li _x FePO ₄ ). Here, x and y are preferably 0 <x ≦ 1 and 0 ≦ y ≦ 1.

  A more preferable active material is a lithium cobalt composite oxide or a lithium manganese composite oxide. Since these active materials have high ion conductivity, diffusion of lithium ions in the positive electrode active material is unlikely to be a rate-determining step in combination with the negative electrode active material described above. For this reason, the said active material is excellent in compatibility with the lithium titanium complex oxide in the said negative electrode active material.

  The conductive agent improves the current collection performance of the active material and suppresses the contact resistance with the current collector. Examples of the conductive agent include carbonaceous materials such as acetylene black, carbon black, and graphite.

  The binder binds the active material and the conductive agent. Examples of the binder include polytetrafluoroethylene (PTFE), polyvinylidene fluoride, and fluorine-based rubber.

  The active material, conductive agent and binder in the positive electrode layer are preferably blended at a ratio of 80% to 95% by weight, 3% to 18% by weight and 2% to 17% by weight, respectively. . The conductive agent can exert the above-described effects by setting the amount to 3% by weight or more. By making the amount of the conductive agent 18% by weight or less, decomposition of the non-aqueous electrolyte on the surface of the conductive agent under high temperature storage can be reduced. A sufficient positive electrode strength can be obtained by setting the binder to an amount of 2% by weight or more. By setting the amount of the binder to 17% by weight or less, the amount of the binder, which is an insulating material in the positive electrode, can be reduced, and the internal resistance can be reduced.

  The current collector is preferably, for example, an aluminum foil or an aluminum alloy foil containing an element such as Mg, Ti, Zn, Mn, Fe, Cu, or Si.

  The positive electrode is produced, for example, by suspending an active material, a conductive agent, and a binder in a commonly used solvent to prepare a slurry, applying the slurry to a current collector, drying, and then applying a press. The The positive electrode may also be produced by forming an active material, a conductive agent and a binder in the form of a pellet to form a negative electrode layer on a current collector.

4) Non-aqueous electrolyte Examples of the non-aqueous electrolyte include a liquid non-aqueous electrolyte prepared by dissolving an electrolyte in an organic solvent, or a gel non-aqueous electrolyte obtained by combining a liquid electrolyte and a polymer material.

  The liquid non-aqueous electrolyte is preferably dissolved in an organic solvent at a concentration of 0.5M to 2.5M.

Examples of electrolytes are lithium perchlorate (LiClO ₄ ), lithium hexafluorophosphate (LiPF ₆ ), lithium tetrafluoroborate (LiBF ₄ ), lithium hexafluoroarsenide (LiAsF ₆ ), trifluorometasulfone Lithium salt of lithium acid (LiCF ₃ SO ₃ ), lithium salt of bistrifluoromethylsulfonylimitolithium [LiN (CF ₃ SO ₂ ) ₂ ], or a mixture thereof. The electrolyte is preferably one that is not easily oxidized even at a high potential, and LiPF ₆ is most preferred.

  Examples of organic solvents are cyclic carbonates such as propylene carbonate (PC), ethylene carbonate (EC), vinylene carbonate; chain carbonates such as diethyl carbonate (DEC), dimethyl carbonate (DMC), and methyl ethyl carbonate (MEC). Cyclic ethers such as tetrahydrofuran (THF), 2-methyltetrahydrofuran (2MeTHF), dioxolane (DOX); chain ethers such as dimethoxyethane (DME) and dietoethane (DEE); or γ-butyrolactone (GBL), acetonitrile ( AN) and sulfolane (SL). These organic solvents can be used alone or in the form of a mixed solvent.

  Examples of the polymer material include polyvinylidene fluoride, polyacrylonitrile (PAN), and polyethylene oxide (PEO).

  A preferable organic solvent is a mixed solvent in which at least two of the group consisting of propylene carbonate (PC), ethylene carbonate (EC) and (diethyl carbonate (DEC)) are mixed, or a mixture containing γ-butyrolactone (GBL). It is a solvent.

5) Separator Examples of the separator include a porous film containing polyethylene, polypropylene, cellulose, or polyvinylidene fluoride, or a synthetic resin nonwoven fabric. A preferred porous film is made of polyethylene or polypropylene, and can be melted at a constant temperature to cut off the current, thereby improving safety.

  Next, the nonaqueous electrolyte battery according to the embodiment (for example, a flat type nonaqueous electrolyte battery whose exterior material is a laminate film) will be described more specifically with reference to FIGS. FIG. 1 is a cross-sectional view of a thin nonaqueous electrolyte battery, and FIG. 2 is an enlarged cross-sectional view of part A of FIG. Each figure is a schematic diagram for promoting explanation and understanding of the invention, and its shape, dimensions, ratio, etc. are different from the actual apparatus. The design can be changed as appropriate.

The flat wound electrode group 1 is housed in a bag-shaped exterior material 2 made of a laminate film in which an aluminum foil is interposed between two resin layers. The flat wound electrode group 1 is formed by winding a laminate of the negative electrode 3, the separator 4, the positive electrode 5, and the separator 4 in this order from the outside in a spiral shape and press-molding. As shown in FIG. 2, the outermost negative electrode 3 has a configuration in which a negative electrode layer 3b is formed on one surface on the inner surface side of the negative electrode current collector 3a. The other negative electrode 3 is configured by forming negative electrode layers 3b on both surfaces of a negative electrode current collector 3a. The active material in the negative electrode layer 3b contains a titanium composite oxide. The titanium composite oxide contains a monoclinic β-type titanium composite oxide as a main phase, and the main peak of the monoclinic β-type titanium composite oxide by a wide angle X-ray diffraction method using CuKα rays as an X-ray source. The integrated intensity of the main peak appearing at 2θ = 25.1 to 25.5 ° attributed to at least one subphase selected from anatase TiO ₂ and H ₂ Ti ₈ O ₁₇ The composition has a relative value of 30 or less. In the titanium composite oxide, the crystallite diameter calculated from the main peak of the monoclinic β-type titanium composite oxide obtained by the wide-angle X-ray diffraction method is 5 nm or more. The positive electrode 5 is configured by forming a positive electrode layer 3b on both surfaces of a positive electrode current collector 5a.

  In the vicinity of the outer peripheral end of the wound electrode group 1, the negative electrode terminal 6 is connected to the negative electrode current collector 3 a of the outermost negative electrode 3, and the positive electrode terminal 7 is connected to the positive electrode current collector 5 a of the inner positive electrode 5. . The negative electrode terminal 6 and the positive electrode terminal 7 are extended to the outside from the opening of the bag-shaped exterior material 2. For example, the liquid non-aqueous electrolyte is injected from the opening of the bag-shaped exterior material 2. The wound electrode group 1 and the liquid nonaqueous electrolyte are completely sealed by heat-sealing the opening of the bag-shaped outer packaging material 2 with the negative electrode terminal 6 and the positive electrode terminal 7 interposed therebetween.

  The negative electrode terminal is made of, for example, a material having electrical stability and conductivity in a range where the potential with respect to the lithium ion metal is 1.0 V or more and 3.0 V or less. Specifically, aluminum or an aluminum alloy containing an element such as Mg, Ti, Zn, Mn, Fe, Cu, or Si can be given. In order to reduce the contact resistance with the negative electrode current collector, the negative electrode terminal is preferably made of the same material as the negative electrode current collector.

  The positive electrode terminal is made of a material having electrical stability and conductivity in a range of a potential of 3.0 to 4.25 V with respect to a lithium ion metal. Specifically, aluminum or an aluminum alloy containing an element such as Mg, Ti, Zn, Mn, Fe, Cu, or Si can be given. The positive electrode terminal is preferably made of the same material as that of the positive electrode current collector in order to reduce contact resistance with the positive electrode current collector.

  Next, the battery pack according to the embodiment will be described in detail.

  The battery pack according to the embodiment includes a plurality of the nonaqueous electrolyte batteries (unit cells) described above, and each unit cell is electrically connected in series, in parallel, or in series and in parallel.

  Such a battery pack has excellent cycle characteristics.

  Since the titanium composite oxide contained in the negative electrode active material is less mixed with an impurity phase and has high crystallinity, a nonaqueous electrolyte battery using this titanium composite oxide can improve large current characteristics and charge / discharge cycle performance. As a result, a battery pack incorporating a plurality of such batteries can improve charge / discharge cycle performance even when charging / discharging with a large current.

  Next, the battery pack according to the embodiment will be specifically described with reference to FIGS. 3 and 4. As the unit cell, a flat type nonaqueous electrolyte battery shown in FIG. 1 is used.

  The plurality of single cells 21 are stacked such that the negative electrode terminal 6 and the positive electrode terminal 7 extending to the outside are aligned in the same direction, and are fastened with an adhesive tape 22 to constitute an assembled battery 23. These unit cells 21 are electrically connected to each other in series as shown in FIG.

  The printed wiring board 24 is disposed to face the side surface of the unit cell 21 from which the negative electrode terminal 6 and the positive electrode terminal 7 extend. On the printed wiring board 24, as shown in FIG. 4, a thermistor 25, a protection circuit 26, and a terminal 27 for energizing external devices are mounted. An insulating plate (not shown) is attached to the surface of the protection circuit board 24 facing the assembled battery 23 in order to avoid unnecessary connection with the wiring of the assembled battery 23.

  The positive electrode side lead 28 is connected to the positive electrode terminal 7 positioned at the lowermost layer of the assembled battery 23, and the tip thereof is inserted into the positive electrode side connector 29 of the printed wiring board 24 and electrically connected thereto. The negative electrode side lead 30 is connected to the negative electrode terminal 6 located in the uppermost layer of the assembled battery 23, and the tip thereof is inserted into the negative electrode side connector 31 of the printed wiring board 24 and electrically connected thereto. These connectors 29 and 31 are connected to the protection circuit 26 through wirings 32 and 33 formed on the printed wiring board 24.

  The thermistor 25 is used to detect 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 34a and the minus side wiring 34b between the protection circuit 26 and the energization terminal 27 to the external device under a predetermined condition. The predetermined condition is, for example, when the temperature detected by the thermistor 25 is equal to or higher than a predetermined temperature. The predetermined condition is when the overcharge, overdischarge, overcurrent, etc. of the cell 21 are detected. This detection of overcharge or the like is performed for each single cell 21 or the entire single 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. 3 and FIG. 4, a voltage detection wiring 35 is connected to each single cell 21, and a detection signal is transmitted to the protection circuit 26 through these wirings 35.

  Protective sheets 36 made of rubber or resin are disposed on the three side surfaces of the assembled battery 23 excluding the side surfaces from which the positive electrode terminal 7 and the negative electrode terminal 6 protrude.

  The assembled battery 23 is stored in a storage container 37 together with the protective sheets 36 and the printed wiring board 24. That is, the protective sheet 36 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 37, 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 23 is located in a space surrounded by the protective sheet 36 and the printed wiring board 24. The lid 38 is attached to the upper surface of the storage container 37.

  In addition, instead of the adhesive tape 22, a heat shrink tape may be used for fixing the assembled battery 23. 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.

  3 and 4 show the configuration in which the unit cells 21 are connected in series, but in order to increase the battery capacity, they may be connected in parallel, or a combination of series connection and parallel connection may be used. The assembled battery packs can be further connected in series and in parallel.

  Moreover, the aspect of a battery pack is changed suitably by a use. The battery pack is preferably one that exhibits excellent cycle characteristics when a large current is taken out. 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.

  As described above, a mixed solvent in which at least two of the group consisting of propylene carbonate (PC), ethylene carbonate (EC) and diethyl carbonate (DEC) are mixed, or a non-aqueous electrolyte containing γ-butyrolactone (GBL). By using it, a nonaqueous electrolyte battery excellent in high temperature characteristics can be obtained. A battery pack provided with an assembled battery having a plurality of such nonaqueous electrolyte batteries is particularly suitable for in-vehicle use.

  Examples will be described below. In addition, unless it exceeds the main point of this invention, it is not limited to the Example described below.

Example 1
<Preparation of positive electrode>
First, 90% by weight of a lithium nickel composite oxide (LiNi _0.82 Co _0.15 Al _0.03 O ₂ ) powder as a positive electrode active material, 5% by weight of acetylene black and 5% by weight of polyvinylidene fluoride as conductive agents were added with N-methylpyrrolidone (NMP). In addition, the slurry is applied to both sides of a current collector made of an aluminum foil having a thickness of 15 μm, dried, and pressed to obtain a positive electrode having an electrode density of 3.15 g / cm ³ . Produced.

<Preparation of titanium composite oxide>
First, potassium carbonate (K ₂ CO ₃ ) and anatase-type titanium oxide (TiO ₂ ) were mixed and baked at 1000 ° C. for 24 hours to synthesize K ₂ Ti ₄ O ₉ . The obtained K ₂ Ti ₄ O ₉ was dry-pulverized with zirconia beads to adjust the particle size, and then washed with pure water to obtain a proton exchange precursor. The obtained proton exchange precursor was put into a 1 M hydrochloric acid solution and subjected to ultrasonic stirring for 1 hour in an environment of 25 ° C. This operation was repeated 12 times, and each time the hydrochloric acid was exchanged and then washed to obtain a proton exchanger. Subsequently, the obtained proton exchanger was baked at 350 ° C. for 3 hours in the air to produce a titanium composite oxide.

  With respect to the obtained titanium composite oxide, the crystallite diameter and the main peak intensity ratio were measured.

  That is, a wide-angle X-ray diffraction pattern using Cu-Kα of a titanium composite oxide was obtained by the measurement method described above. The obtained X-ray diffraction pattern is shown in FIG.

  The crystallite diameter of the titanium composite oxide is calculated from the half width of the X-ray diffraction peak of the (110) plane of the monoclinic β-type titanium composite oxide having a diffraction angle (2θ) of about 24.8 ° as described above. Determined by The crystallite diameter of the titanium composite oxide was 15 nm. In the calculation of the half width of the diffraction peak, it is necessary to correct the line width by the optical system of the diffraction apparatus, and standard silicon powder was used for this correction.

When the peak integrated intensity at 3.59Å (2θ: 24.8 °), which is the main peak of the monoclinic β-type titanium composite oxide, calculated from the X-ray diffraction pattern shown in FIG. The relative value of the integrated intensity of the main peak appearing at 2θ = 25.1 to 25.5 ° attributed to each of anatase TiO ₂ and H ₂ Ti ₈ O ₁₇ was 23.

<Production of negative electrode>
N-methylpyrrolidone (NMP) was added to and mixed with 90% by weight of the obtained titanium composite oxide powder, 5% by weight of acetylene black and 5% by weight of polyvinylidene fluoride to prepare a slurry. This slurry was applied to both surfaces of a current collector made of an aluminum foil having a thickness of 15 μm, dried, and pressed to prepare a negative electrode having an electrode density of 2.0 g / cm ³ .

<Production of electrode group>
A positive electrode, a separator made of a polyethylene porous film having a thickness of 25 μm, a negative electrode and a 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 was housed in a pack made of a laminate film and vacuum dried at 80 ° C. for 24 hours. The laminate film is formed by forming a polypropylene layer on both sides of an aluminum foil having a thickness of 40 μm, and the overall thickness is 0.1 mm.

<Preparation of liquid nonaqueous electrolyte>
Ethylene carbonate (EC) and ethyl methyl carbonate (EMC) were mixed at a volume ratio of 1: 2 to obtain a mixed solvent. A liquid non-aqueous electrolyte was prepared by dissolving 1 M of LiPF ₆ as an electrolyte in this mixed solvent.

<Manufacture of non-aqueous electrolyte secondary batteries>
A liquid non-aqueous electrolyte was poured into a laminate film pack containing the electrode group. Thereafter, the pack was completely sealed by heat sealing, and a non-aqueous electrolyte secondary battery having the structure shown in FIG. 1 and having a width of 35 mm, a thickness of 3.2 mm, and a height of 65 mm was manufactured.

(Examples 2 to 6 and Comparative Example 1)
A titanium composite oxide was synthesized in the same manner as in Example 1 except that the firing temperature of the proton exchanger was changed to Table 1 below. A nonaqueous electrolyte secondary battery was produced in the same manner as in Example 1 except that these titanium composite oxides were used as the negative electrode active material. In addition, the relative value and the crystallite diameter of the integrated intensity of the titanium composite oxide used in Examples 2 to 6 and Comparative Example 1 shown in Table 1 below are wide-angle X-rays using Cu-Kα as in Example 1. A diffraction pattern was created and calculated from this diffraction pattern. The X-ray diffraction pattern of the titanium composite oxide used in Comparative Example 1 is shown in FIG.

  About each battery of Examples 1-6 and Comparative Example 1, 0.2C discharge capacity and 2C discharge capacity were measured under an environment of 25 ° C., and the ratio (%) of 2C discharge capacity to 0.2C discharge capacity was determined. It calculated | required as a maintenance rate (%). The results are shown in Table 1 below.

Moreover, the single electrode was manufactured from the negative electrode used for the battery of Examples 1-6 and the comparative example 1, and the counter electrode which consists of lithium metals. The lithium ion was occluded (charged) up to 1 V (Li / Li ⁺ ) at a current value of 0.1 mA / cm ^{2 in} a single electrode, and then 3 V (Li / Li ⁺ at a current value of 0.1 mA / cm ² ). ) To release (discharge) lithium ions. The amount of electricity discharged at this time was converted to the amount of electricity per unit weight of lithium titanate as the negative electrode active material. The converted value is shown in Table 1 below as the negative electrode capacity.

  As is clear from Table 1, the batteries of Examples 1 to 6 using a titanium composite oxide having a relative value of integral strength of 30 or less and a crystallite diameter of 5 nm or more as a negative electrode active material were used. And a high negative electrode capacity and a high capacity retention ratio (good high-current performance) as compared with the battery of Comparative Example 1 using a titanium composite oxide whose crystallite diameter is outside the above range as the negative electrode active material. I understand.

(Example 7)
A nonaqueous electrolyte secondary battery was produced in the same manner as in Example 1 except that the titanium composite oxide synthesized by the following method was used as the negative electrode active material.

Phosphorus oxide (P ₂ O ₅ ), boron oxide (B ₂ O ₃ ), potassium carbonate (K ₂ CO ₃ ) and anatase-type titanium oxide (TiO ₂ ) are mixed and calcined at 1000 ° C. for 24 hours to obtain P and K ₂ Ti ₄ O ₉ containing B was obtained. The obtained K ₂ Ti ₄ O ₉ was dry-pulverized with zirconia beads to adjust the particle size, and then washed with pure water to obtain a proton exchange precursor. The obtained proton exchange precursor was put into a 1M hydrochloric acid solution and subjected to ultrasonic stirring for 1 hour in an environment at 25 ° C. This operation was repeated 12 times, and each time the hydrochloric acid was exchanged and then washed to obtain a proton exchanger. Subsequently, the obtained proton exchanger was baked at 350 ° C. for 3 hours in the atmosphere to synthesize a titanium composite oxide.

The amount of P and B in the obtained titanium composite oxide was measured by the ICP analysis described above. As a result, the amounts of P and B were 0.230% by weight and 0.010% by weight, respectively. FIG. 7 shows a wide-angle X-ray diffraction pattern using Cu—Kα of the obtained titanium composite oxide. From this wide-angle X-ray diffraction pattern, when the peak integrated intensity of 3.59Å (2θ: 24.8 °), which is the main peak of the monoclinic β-type titanium composite oxide, is set to 100, as in Example 1, anatase The relative value of the integrated intensity of the main peak appearing at 2θ = 25.1 to 25.5 ° attributed to each of the type TiO ₂ and H ₂ Ti ₈ O ₁₇ and the crystallite diameter of the titanium composite oxide were determined. As a result, the relative value of the integrated intensity and the crystallite diameter were 3 or less and 25 nm, respectively.
(Examples 8 to 16 and Comparative Example 2)
A titanium composite oxide was synthesized in the same manner as in Example 7, except that the amounts of P and B (the amount relative to the total amount of titanium composite oxide and P and B) were changed to the ratios shown in Table 2 below. A nonaqueous electrolyte secondary battery was produced in the same manner as in Example 1 except that these titanium composite oxides were used as the negative electrode active material. In addition, the relative value and the crystallite diameter of the integrated intensity of the titanium composite oxide used in Examples 8 to 16 and Comparative Example 2 shown in Table 2 below are wide-angle X-rays using Cu—Kα as in Example 1. A diffraction pattern was created and calculated from this diffraction pattern.

  About each battery of Examples 7-16 and the comparative example 2, 0.2C discharge capacity and 2C discharge capacity were measured in 25 degreeC environment, and the ratio (%) of 2C discharge capacity with respect to 0.2C discharge capacity was capacity | capacitance. It calculated | required as a maintenance rate (%). The results are shown in Table 2 below.

Moreover, the single electrode was manufactured from the negative electrode used for the battery of Examples 7-16 and the comparative example 2, and the counter electrode which consists of lithium metals. The lithium ion was occluded (charged) up to 1 V (Li / Li ⁺ ) at a current value of 0.1 mA / cm ^{2 in} a single electrode, and then 3 V (Li / Li ⁺ at a current value of 0.1 mA / cm ² ). ) To release (discharge) lithium ions. The amount of electricity discharged at this time was converted to the amount of electricity per unit weight of lithium titanate as the negative electrode active material. The converted value is shown in Table 2 below as the negative electrode capacity.

  As is apparent from Table 2, a titanium composite oxide containing at least one element selected from a predetermined amount of P and B, having a relative value of integral intensity of 30 or less, and a crystallite diameter of 5 nm or more is used as the negative electrode active material. The batteries of Examples 7 to 16 used had a higher negative electrode capacity and higher capacity than the battery of Comparative Example 2 in which the titanium composite oxide in which the content of the element (P) exceeded 3% by weight was used as the negative electrode active material. It can be seen that the maintenance factor (good large current performance) is exhibited. Moreover, it turns out that the battery of Examples 7-16 shows a much higher capacity | capacitance maintenance factor (good large current performance) compared with the battery of Examples 1-6 which does not contain the said element (P, B).

  As mentioned above, although embodiment of this invention was described, this invention is not restricted to these, In the category of the summary of the invention as described in a claim, it can change variously. In addition, the present invention can be variously modified without departing from the scope of the invention in the implementation stage. Furthermore, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment.

According to a first aspect of the present embodiment, the exterior includes: an exterior material; a current collector, and a positive electrode layer formed on one or both surfaces of the current collector and including an active material, a conductive material, and a binder. A positive electrode housed in a material; a current collector, and a negative electrode layer formed on one or both surfaces of the current collector and containing an active material containing titanium oxide or titanium composite oxide, a conductive material, and a binder with the door, the positive electrode and spatially separated anode housed in inside the outer package; and the nonaqueous electrolyte housed in the outer package within; provided, said titanium oxide or titanium composite oxide The integrated intensity of the main peak of the monoclinic β-type titanium composite oxide by a wide angle X-ray diffraction method including a monoclinic β-type titanium composite oxide as a main phase and CuKα rays as an X-ray source is 100. when a, anatase TiO ₂ and H ₂ Ti ₈ O ₁₇ The relative value of the integrated intensity of the main peak appearing at 2θ = 25.1 to 25.5 ° attributed to at least one subphase is 30 or less, and the titanium oxide or the titanium composite oxide has the wide angle. Provided is a nonaqueous electrolyte battery having a crystallite diameter of 5 nm or more calculated from the main peak of the monoclinic β-type titanium composite oxide obtained by the X-ray diffraction method.

According to the second aspect of the present embodiment, there is provided a battery pack comprising a plurality of the non-aqueous electrolyte batteries of the first aspect, wherein each battery is electrically connected in series, in parallel or in series and in parallel.

Claims (8)

An active material for a non-aqueous electrolyte battery containing titanium oxide or titanium composite oxide,
The titanium oxide or titanium composite oxide contains a monoclinic β-type titanium composite oxide as a main phase, and the monoclinic β-type titanium composite by a wide angle X-ray diffraction method using CuKα rays as an X-ray source. When the integrated intensity of the main peak of the oxide is 100, the main appearing at 2θ = 25.1 to 25.5 ° belonging to at least one subphase selected from anatase TiO ₂ and H ₂ Ti ₈ O ₁₇ The relative value of the integrated intensity of the peak is 30 or less, and the titanium oxide or titanium composite oxide is calculated from the main peak of the monoclinic β-type titanium composite oxide obtained by the wide-angle X-ray diffraction method. The active material for nonaqueous electrolyte batteries whose crystallite diameter is 5 nm or more.   The battery active material according to claim 1, wherein the titanium oxide or the titanium composite oxide has a crystallite diameter of 20 nm to 300 nm. The battery active material according to claim 1, wherein the titanium oxide or the titanium composite oxide has a specific surface area of 5 m ² / g or more and 50 m ² / g or less. Exterior material;
A positive electrode housed in the exterior material;
A negative electrode containing an active material containing titanium oxide or a titanium composite oxide and spatially separated from the positive electrode in the outer package; and a nonaqueous electrolyte housed in the outer package;
Comprising
The titanium oxide or titanium composite oxide contains a monoclinic β-type titanium composite oxide as a main phase, and the monoclinic β-type titanium composite by a wide angle X-ray diffraction method using CuKα rays as an X-ray source. When the integrated intensity of the main peak of the oxide is 100, the main appearing at 2θ = 25.1 to 25.5 ° belonging to at least one subphase selected from anatase TiO ₂ and H ₂ Ti ₈ O ₁₇ The relative value of the integrated intensity of the peak is 30 or less, and the titanium oxide or titanium composite oxide is calculated from the main peak of the monoclinic β-type titanium composite oxide obtained by the wide-angle X-ray diffraction method. A nonaqueous electrolyte battery having a crystallite diameter of 5 nm or more.   The non-aqueous electrolyte battery according to claim 4, wherein the positive electrode includes a lithium nickel composite oxide or a lithium manganese composite oxide.   The non-aqueous electrolyte battery according to claim 4, wherein the exterior material is formed from a laminate film.   A battery pack comprising a plurality of the nonaqueous electrolyte batteries according to any one of claims 4 to 6, wherein each battery is electrically connected in series, in parallel, or in series and in parallel.   The battery pack according to claim 7, further comprising a protection circuit capable of detecting the voltage of each non-aqueous electrolyte battery.

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