JP6523483B2 - Positive electrode active material for non-aqueous electrolyte battery, positive electrode for non-aqueous electrolyte battery, non-aqueous electrolyte battery and battery pack, vehicle - Google Patents

Description

  Embodiments of the present invention relate to a positive electrode active material for a non-aqueous electrolyte battery, a positive electrode for a non-aqueous electrolyte battery, a non-aqueous electrolyte battery, and a battery pack.

  As a positive electrode active material for non-aqueous electrolyte batteries, phosphates such as lithium manganese iron phosphate have been studied. As a positive electrode for non-aqueous electrolyte batteries, for example, a positive electrode containing lithium manganese iron phosphate / carbon nanocomposite powder and an inorganic binder is known.

In lithium iron phosphate, side reactions at high potentials have been regarded as problems due to low reaction activity and high reaction potential. For example, in a non-aqueous electrolyte battery using lithium iron phosphate lithium as a positive electrode active material, lithium lithium iron phosphate and non-aqueous electrolyte react with charge and discharge, and a film of the reaction product is iron phosphate It may be formed on the surface of lithium manganese. The film formed on the surface of lithium manganese iron phosphate increases the electrical resistance between lithium manganese lithium iron phosphate and the non-aqueous electrolyte, reduces the discharge capacity at high discharge rates, and shortens the cycle life. It can be a factor.
As described above, in the non-aqueous electrolyte battery using lithium iron phosphate lithium as the positive electrode active material, the discharge capacity at a high discharge rate may be easily reduced, and the cycle life may be short.

JP 2011-528483 gazette

  The problem to be solved by the present invention is that although the phosphate is used as a positive electrode active material, a decrease in discharge capacity at a high discharge rate is unlikely to occur, and a positive electrode active material for non-aqueous electrolyte batteries having a long cycle life, A positive electrode for a water electrolyte battery, a non-aqueous electrolyte battery, and a battery pack.

The positive electrode active material for a non-aqueous electrolyte battery of the embodiment has active material particles and a film on the surface of the active material particles. Active material _particles, the _{LiMn 1-x-y Fe x} A y PO 4 (A, represents Mg, Ca, Al, Ti, at least one element selected from the group consisting of Zn and Zr, x and y, It is represented by 0 <x <= 0.3 and 0 <= y <= 0.1). The coating comprises an oxide containing boron and lithium and a carbonaceous material.

BRIEF DESCRIPTION OF THE DRAWINGS The schematic sectional drawing of the positive electrode active material for non-aqueous electrolyte batteries which concerns on 1st Embodiment. The partial expanded sectional view of FIG. The schematic sectional drawing which shows an example of the non-aqueous electrolyte battery which concerns on 3rd Embodiment. The expanded sectional view of the A section of FIG. FIG. 13 is a partial cutaway perspective view showing an example of another non-aqueous electrolyte battery according to a third embodiment. The expanded sectional view of the B section of FIG. The schematic disassembled perspective view which shows the battery pack which concerns on 4th Embodiment. FIG. 8 is a block diagram showing an electric circuit of the battery pack of FIG. 7;

Hereinafter, a positive electrode active material for a non-aqueous electrolyte battery, a positive electrode for a non-aqueous electrolyte battery, a non-aqueous electrolyte battery, and a battery pack of the embodiment will be described with reference to the drawings. In the following description of the drawings, the same or similar parts will be denoted by the same or similar reference numerals, and overlapping descriptions will be omitted. However, it should be noted that the drawings are schematic, and the relationship between the thickness and the planar dimension, the ratio of the thickness of each layer, etc. may be different from the actual one. Therefore, specific thicknesses and dimensions should be determined in consideration of the following description. It is a matter of course that portions having different dimensional relationships and ratios from one another are included among the drawings.
The embodiments described below illustrate apparatuses and methods for embodying the technical idea of the invention, and the technical idea of the invention includes the material, shape, structure, arrangement, etc. of components. Does not specify the following. The technical ideas of the invention can be variously modified within the scope of the claims.

First Embodiment
According to the present embodiment, the active material particle and the film containing the oxide containing the boron and the lithium filled in the porous carbonaceous material and the porous carbonaceous material on the surface of the active material particle are included. The thickness of the coating is 1 nm or more, and the oxide containing boron and lithium is contained in an amount of 0.5% by mass or more and 5.0% by mass or less based on the active material particles as the amount of boron. There is provided a positive electrode active material for a non-aqueous electrolyte battery, which contains a carbonaceous material in an amount of 0.5% by mass or more and 5.0% by mass or less based on active material particles . Hereinafter, in the present specification, an oxide containing boron and lithium may be referred to as a boron-lithium containing oxide.

FIG. 1 is a schematic cross-sectional view for explaining the positive electrode active material for a non-aqueous electrolyte battery of the present embodiment, and FIG. 2 is a partially enlarged cross-sectional view of FIG.
In FIGS. 1 and 2, the positive electrode active material 10 for a non-aqueous electrolyte battery has active material particles 11 and a film 12 formed on the surface thereof.

Active material particles 11 may _include a phosphate salt represented by _{LiMn 1-x-y Fe x} A y PO 4. Here, A represents at least one element selected from the group consisting of Mg, Ca, Al, Ti, Zn and Zr, and x and y are 0 <x ≦ 0.3, 0 ≦ y ≦ 0.1. Meet. The active material particles 11 preferably have an olivine structure. The average particle diameter of the primary particles of the active material particles 11 is preferably in the range of 0.01 μm to 1 μm, and more preferably in the range of 0.01 μm to 0.5 μm. By setting the average particle diameter of the active material particles 11 in the above range, the influence of the diffusion resistance of lithium ions in the active material can be reduced, so that the discharge capacity at a high discharge rate can be improved. Also, the primary particles may be aggregated to form secondary particles of 10 μm or less.

  The film 12 contains a boron-lithium containing oxide 13 and a carbonaceous material 14 as shown in FIG. The thickness of the film 12 is preferably in the range of 1 nm to 50 nm, and more preferably in the range of 5 nm to 20 nm. By setting the thickness of the film 12 in the above range, the surface of the active material particles 11 is stably protected from the non-aqueous electrolyte even when used as the positive electrode active material of the non-aqueous electrolyte battery. Side reactions with the non-aqueous electrolyte are less likely to occur.

The boron-lithium-containing oxide 13 preferably has a function of conducting lithium ions. The boron-lithium-containing oxide 13 is preferably a composite of lithium oxide and boron oxide represented by zLi ₂ O-wB ₂ O ₃ . The molar ratio of z and w is preferably in the range of 0.5: 1 to 5: 1, and more preferably in the range of 0.5: 1 to 2: 1. A composite having a molar ratio of z to w in the above range has a high density, and the effect of suppressing the side reaction with the non-aqueous electrolyte is improved. The content of the boron-lithium-containing oxide 13 is preferably in the range of 0.5% by mass or more and 5.0% by mass or less with respect to the active material particles 11 as the amount of boron, preferably 0.5% by mass or more. More preferably, it is in the range of 0% by mass or less. The amount of boron can be measured by quantifying the solution obtained by dissolving the active material particles 11 with acid and diluting with pure water by ICP (Inductively Coupled Plasma) analysis.

  The carbonaceous material 14 preferably has electrical conductivity. The carbonaceous material 14 is preferably attached to the surface of the active material particles 11 in a fibrous form. The fibrous carbonaceous material preferably extends in a three-dimensional network along the surface of the active material particles 11. That is, the carbonaceous material 14 is preferably in a porous state having pores. The film 12 is preferably in a form in which the boron-lithium containing oxide 13 is filled in the pores of the porous carbonaceous material 14. The content of the carbonaceous material 14 is preferably in the range of 0.5% by mass to 5.0% by mass with respect to the active material particles 11. The amount of carbon contained in the film 12 is a quantitative analysis of the elemental composition on the surface of the active material by SEM-EDX (Scanning Electron Microscopy (Energy Dispersive X-ray Spectroscopy)). By combining quantitative analysis of film thickness and composition by XPS (X-ray Photoelectron Spectroscopy) in the depth direction, the thickness of film 12 and the amount of carbon and boron contained in film 12 can be obtained. It can be calculated by making it correspond to the amount of boron obtained by ICP analysis.

The positive electrode active material for a non-aqueous electrolyte battery of the present embodiment has the maximum peak of the (311) plane in the interface portion of the active material particles in the X-ray diffraction pattern measured by the X-ray diffraction method using Cu-Kα rays. It is preferable that the diffraction angle 2θ is shifted to a high angle in the range of 0.01 ° or more and 0.15 ° or less than the diffraction angle 2θ of the maximum peak of the (311) plane in the bulk portion of the active material particles. The X-ray diffraction pattern of the interface portion of the active material particles can be measured by in-plane X-ray diffraction. In-plane X-ray diffraction is a method of fixing the incident angle of X-rays near the total reflection critical angle and evaluating a lattice plane perpendicular to the sample surface. In this in-plane X-ray diffraction method, the incident depth of X-rays to the sample is usually several tens of nm. The X-ray diffraction pattern of the bulk portion of the active material particles can be measured by out-of-plane X-ray diffraction. Out-of-plane X-ray diffraction is a method of evaluating lattice planes parallel to the sample surface by changing the incident angle of X-rays. In this out-of-plane X-ray diffraction method, the incident depth of X-rays to the sample is usually several tens of μm.
When the active material to be measured is included as the positive electrode active material of the non-aqueous electrolyte battery, pretreatment is performed as follows.
First, the non-aqueous electrolyte battery is charged to bring it into a state close to a state in which lithium ions are completely separated from the crystal of the positive electrode active material. Next, the nonaqueous electrolyte battery is disassembled in an argon-filled glove box to take out the electrode. The removed electrode is washed with an appropriate solvent and dried under reduced pressure. As a solvent, for example, ethyl methyl carbonate can be used. After washing and drying, make sure that there are no white precipitates such as lithium salt on the surface.

  The fact that the diffraction angle 2θ of the maximum peak of the (311) plane in the interface part of the active material particle is shifted to a high angle suggests that a part of the interface of the active material particle is replaced with boron It is thought that The reason for this is that when the X-ray diffraction patterns of the interface portion and the bulk portion are measured for the active material particles before and after forming the film containing the boron-lithium containing oxide, the diffraction angle 2θ of the (311) plane of the bulk portion Is the same as before and after the formation of the film, but the diffraction angle 2θ of the (311) plane of the interface portion is shifted to a high angle after the formation of the film. By firmly bonding the surface of the active material particle to the boron-lithium-containing oxide so that the interface of the active material particle is replaced by boron, the film is less likely to be peeled off from the active material particle, and the active material particle is It can be stably protected over a long period of time.

Next, a method of manufacturing the positive electrode active material for a non-aqueous electrolyte battery of the present embodiment will be described.
The positive electrode active material for a non-aqueous electrolyte battery is produced, for example, by producing a porous carbonaceous material-coated active material particle, and then filling the carbonaceous material of the active material particle with a boron-lithium-containing oxide. can do.

  As a method of producing the active material particles coated with the porous carbonaceous material, for example, the following method can be used. First, active material particles are produced by a hydrothermal method in the presence of an organic compound to obtain active material particles whose surface is coated with an organic compound. Next, the active material particles are heat-treated to thermally decompose the organic compound into a carbonaceous material. As the organic compound, a water-soluble polymer such as sodium carboxymethylcellulose can be used.

  Also, for active material particles coated with porous carbonaceous material, for example, active material particles produced by a solid phase method and an organic compound are mixed to obtain active material particles having an organic compound attached to the surface, and then The active material particles can be heat-treated to thermally decompose the organic compound to form a carbonaceous material.

A solid phase method or a liquid phase method can be used as a method of filling the boron-lithium containing oxide in the carbonaceous substance of the active material particles coated with the porous carbonaceous substance, but the liquid phase method desirable.
As a filling method of the boron-lithium containing oxide by a liquid phase method, for example, the following method can be used. First, a dispersion liquid in which active material particles coated with a carbonaceous material are dispersed in a solvent in which a lithium compound and a boron compound are dissolved is prepared. Next, the dispersion is heat-treated at 80 ° C. with stirring to allow the boron compound and the lithium compound to enter the pores of the carbonaceous material while evaporating the solvent to obtain a precursor powder. Next, the obtained precursor powder is subjected to a baking treatment to react the boron compound and the lithium compound which have entered the pores of the carbonaceous material, thereby forming a boron-lithium containing oxide. The temperature of the baking treatment is usually 450 ° C. or more and 600 ° C. or less. The heat treatment time is usually 3 hours or more and 10 hours or less.

Examples of the solvent used in the liquid phase method include alcohols such as methanol and ethanol, organic solvents such as NMP, and water. Among these solvents, it is desirable to use an organic solvent in consideration of the dispersibility of the active material particles and the solubility of the lithium compound and the boron compound. As a lithium compound, it is desirable to use lithium hydroxide and lithium nitrate. As the boron compound, it is preferable to use boric acid, boron oxide (B 2 _{O 3).} Furthermore, it is also desirable to use lithium borate as a compound containing lithium and boron.

  According to the positive electrode active material for a non-aqueous electrolyte battery of the present embodiment described above, a film containing an oxide containing boron and lithium (boron-lithium-containing oxide) and a carbonaceous material is formed on the surface of active material particles. Thus, side reactions between the active material particles and the non-aqueous electrolyte are less likely to occur. For this reason, the non-aqueous electrolyte battery using the positive electrode active material for non-aqueous electrolyte batteries of this embodiment has a high discharge rate due to the film of the reaction product of the non-aqueous electrolyte being formed on the surface of the active material particles. It is difficult for the decrease of discharge capacity to occur and the cycle life is extended.

Second Embodiment
According to the present embodiment, a positive electrode for a non-aqueous electrolyte battery is provided which has a current collector and a positive electrode active material layer formed on the current collector. In the present embodiment, the positive electrode active material for a non-aqueous electrolyte battery of the first embodiment described above is used as the positive electrode active material. The positive electrode active material layer is formed on one side or both sides of the current collector.

  The current collector is preferably an aluminum foil or an aluminum alloy foil containing one or more elements selected from Mg, Ti, Zn, Mn, Fe, Cu and Si. Further, in consideration of expansion and contraction of the active material accompanying charge and discharge, an electrolytic foil having a rough surface is more preferable.

  The compounding ratio of the positive electrode active material, the conductive agent, and the binder contained in the positive electrode active material layer is 80% by mass to 95% by mass of the positive electrode active material, 3% by mass to 18% by mass of the conductive agent, and the binder It is preferable that is 2 mass% or more and 17 mass% or less. The conductive agent can exhibit the effect of securing the conductivity of the electrode by setting the amount to 3% by mass or more. The conductive agent can reduce the decomposition of the non-aqueous electrolyte on the surface of the conductive agent under high temperature storage by setting the amount to 18% by mass or less. By setting the binder in an amount of 2% by mass or more, sufficient electrode strength can be obtained. The binder can reduce the internal resistance in the positive electrode active material layer by setting the amount to 17% by mass or less.

  Examples of conductive agents include acetylene black, carbon black, graphite, carbonaceous materials such as carbon nanofibers and carbon nanotubes. These carbonaceous materials may be used alone or a plurality of carbonaceous materials may be used.

  The binder binds the positive electrode active material, the conductive agent, and the current collector. Examples of the binder include polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVdF), and fluorine-based rubber, acrylic resin, cellulose such as carboxymethyl cellulose and the like.

Next, a method of manufacturing the positive electrode for a non-aqueous electrolyte battery of the present embodiment will be described.
First, a positive electrode active material, a conductive agent and a binder are suspended in a solvent to prepare a slurry. The slurry is applied to one side or both sides of the current collector and dried to form a positive electrode active material layer. Then apply the press. Alternatively, the positive electrode active material, the conductive agent, and the binder may be formed into pellets and used as a positive electrode active material layer.

  According to the positive electrode for a non-aqueous electrolyte battery of the present embodiment described above, since the above-described positive electrode active material for a non-aqueous electrolyte battery of the first embodiment is used as the positive electrode active material, the non-aqueous electrolyte battery of the present embodiment In a non-aqueous electrolyte battery having a positive electrode, the decrease in discharge capacity at a high discharge rate does not easily occur, and the cycle life is extended.

Third Embodiment
According to the present embodiment, a non-aqueous electrolyte battery including a positive electrode, a negative electrode, and a non-aqueous electrolyte is provided. In the present embodiment, the positive electrode for a non-aqueous electrolyte battery according to the second embodiment described above is used as the positive electrode.

  As an example of the non-aqueous electrolyte battery according to the present embodiment, a non-aqueous electrolyte battery in which the exterior member is formed of a laminate film will be described. FIG. 3 is a schematic cross-sectional view of the non-aqueous electrolyte battery, and FIG. 4 is an enlarged cross-sectional view of a portion A of FIG. Each figure is a schematic diagram for promoting the explanation and understanding of the invention, and the shape, size, ratio, etc. are different from the actual device in some places, but these refer to the following explanation and known techniques. The design can be changed as appropriate.

In the non-aqueous electrolyte battery 20 shown in FIG. 3, the flat wound electrode group 21 is housed in a bag-like exterior member 22 formed of a laminate film in which an aluminum foil is interposed between two resin layers. The flat wound electrode group 21 is formed by spirally winding and pressing a laminate obtained by laminating the negative electrode 23, the separator 24, the positive electrode 25, and the separator 24 in this order from the outside. In the outermost negative electrode 23, as shown in FIG. 3, a negative electrode layer 23b is formed on one side of the inner surface of the negative electrode current collector 23a. The other negative electrode 23 has a negative electrode layer 23 b formed on both sides of the negative electrode current collector 23 a. The active material in the negative electrode layer 23b contains a titanium oxide compound having a TiO ₂ (B) structure. The positive electrode 25 has a positive electrode layer 25 b formed on both sides of the positive electrode current collector 25 a.

  Near the outer peripheral end of the wound electrode group 21, the negative electrode terminal 26 is connected to the negative electrode current collector 23 a of the outermost negative electrode 23, and the positive electrode terminal 27 is connected to the positive electrode current collector 25 a of the inner positive electrode 25. . The negative electrode terminal 26 and the positive electrode terminal 27 are extended from the opening of the bag-like exterior member 22 to the outside. The liquid non-aqueous electrolyte is injected from the opening of the bag-like exterior member 22. The wound electrode group 21 and the liquid non-aqueous electrolyte are completely sealed by heat sealing the opening of the bag-like exterior member 22 with the negative electrode terminal 26 and the positive electrode terminal 27 extended to the outside.

  In the non-aqueous electrolyte battery of the present embodiment, the positive electrode for the non-aqueous electrolyte battery of the second embodiment described above is used as the positive electrode. Hereinafter, the negative electrode, the non-aqueous electrolyte, the separator, the exterior member, the positive electrode terminal, and the negative electrode terminal used for the non-aqueous electrolyte battery of the present embodiment will be described in detail.

(Negative electrode)
The negative electrode includes a negative electrode current collector and a negative electrode active material layer. The negative electrode active material layer contains a negative electrode active material, a conductive agent, and a binder. The negative electrode active material layer is formed on one side or both sides of the negative electrode current collector.
The negative electrode active material contains a titanium composite oxide. The titanium complex oxide is a spinel structure such as lithium titanate, monoclinic β-type titanium complex oxide, anatase type titanium complex oxide, ramsdelide type lithium titanate, TiNb ₂ O ₇ , Ti ₂ Nb ₂ O ₉ and the like. Titanium-containing oxides. In addition, lithium titanate has, for example, a monoclinic crystal structure and is represented by a general formula Li _x Ti _1-y M _{1 y} Nb _2-z M 2 _z O _{7 ± δ} , and M 1 is Zr, Si At least one compound selected from the group consisting of Sn, Fe, Co, Mn and Ni, and M2 is at least one compound selected from the group consisting of V, Nb, Ta, Mo, W and Bi, And a compound having 0 ≦ x ≦ 5, 0 ≦ y ≦ 1, 0 ≦ z ≦ 2, δ ≦ 0.3, and a crystal structure of orthorhombic crystal form, and the general formula Li _{2+ w} Na _2-x M1 is represented by _{y Ti 6-z M2 z O} 14 + δ, M1 is Cs, K, M2 comprises Zr, Sn, V, Nb, Ta, Mo, W, Fe, Co, Mn, at least one of Al A compound, wherein 0 ≦ w ≦ 4, 0 ≦ x ≦ 2, 0 ≦ y ≦ 2, 0 ≦ z ≦ 6, − It can be used .5 ≦ δ ≦ 0.5, compound. Among them, lithium titanate having a spinel structure is preferable because it is excellent in cycle characteristics and rate characteristics. In addition, niobium complex oxide may be included. For example, Nb ₂ O ₅ , Nb ₁₂ O _{29 and the} like can be mentioned.

  The compounding ratio of the negative electrode active material, the conductive agent and the binder is 70% by mass to 96% by mass of the negative electrode active material, 2% by mass to 28% by mass of the conductive agent, and 2% by mass to 28% by mass of the binder It is preferable to be in the range of% or less. If the amount of the conductive agent is less than 2% by mass, the current collection performance of the negative electrode active material layer may be degraded, and the large current characteristics of the non-aqueous electrolyte battery may be degraded. In addition, if the binder is less than 2% by mass, the binding properties of the negative electrode active material layer and the negative electrode current collector may be reduced, and the cycle characteristics may be reduced. On the other hand, the conductive agent and the binder are each preferably 28% by mass or less from the viewpoint of increasing the capacity.

  The negative electrode current collector is made of an aluminum foil or an aluminum alloy foil containing an element such as Mg, Ti, Zn, Mn, Fe, Cu and Si, which is electrochemically stable in a potential range nobler than 1.0 V Preferably it is formed.

  The negative electrode can be produced, for example, by the following method. First, a negative electrode active material, a conductive agent and a binder are suspended in a solvent to prepare a slurry. The slurry is applied to one side or both sides of the negative electrode current collector and dried to form a negative electrode active material layer. Then apply the press. Alternatively, the negative electrode active material, the conductive agent, and the binder can be formed into pellets and used as a negative electrode active material layer.

(Non-aqueous electrolyte)
As the non-aqueous electrolyte, a liquid non-aqueous electrolyte or a gel non-aqueous electrolyte can be used. The liquid non-aqueous electrolyte is prepared by dissolving the electrolyte in an organic solvent. The concentration of the electrolyte is preferably in the range of 0.5 to 2.5 mol / l. The gel non-aqueous electrolyte is prepared by combining a liquid electrolyte and a polymer material.

Examples of electrolytes include lithium perchlorate (LiClO ₄ ), lithium hexafluorophosphate (LiPF ₆ ), lithium tetrafluoroborate (LiBF ₄ ), lithium arsenic hexafluoride (LiAsF ₆ ), trifluorometa. Included are lithium salts such as lithium sulfonate (LiCF ₃ SO ₃ ) and bis trifluoromethylsulfonylimitolithium [LiN (CF ₃ SO ₂ ) ₂ ]. These electrolytes can be used alone or in combination of two or more. The electrolyte preferably contains LiPF _6.

  Examples of the organic solvent include propylene carbonate (PC), ethylene carbonate (EC), cyclic carbonate such as vinylene carbonate; linear carbonate such as diethyl carbonate (DEC), dimethyl carbonate (DMC) and methyl ethyl carbonate (MEC) Carbonates; cyclic ethers such as tetrahydrofuran (THF), 2-methyltetrahydrofuran (2 MeTHF), dioxolane (DOX); linear ethers such as dimethoxyethane (DME), dietethane (DEE); γ-butyrolactone (GBL), α- Methyl γ-butyrolactone (MBL) acetonitrile (AN) and sulfolane (SL) are included. These organic solvents can be used alone or in combination of two or more.

  Examples of more preferable organic solvents include two or more selected from the group consisting of propylene carbonate (PC), ethylene carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), and methyl ethyl carbonate (MEC) And a mixed solvent containing γ-butyrolactone (GBL). By using such a mixed solvent, a non-aqueous electrolyte battery excellent in low temperature characteristics can be obtained.

  Examples of polymeric materials include polyvinylidene fluoride (PVdF), polyacrylonitrile (PAN), and polyethylene oxide (PEO).

(Separator)
As the separator, for example, a porous film formed of a material such as polyethylene, polypropylene, cellulose and polyvinylidene fluoride (PVdF), a synthetic resin non-woven fabric, or the like can be used. Among them, a porous film made of polyethylene or polypropylene can be melted at a certain temperature to interrupt the current, which is preferable from the viewpoint of improving safety.

(Exterior member)
As the exterior member, a bag-like container made of a laminate film or a metal container is used. The shape may, for example, be flat, square, cylindrical, coin, button, sheet or laminate. Of course, in addition to the small battery loaded on the portable electronic device etc., a large battery loaded on a two- or four-wheeled automobile etc. may be used.

  As a laminate film, a multilayer film in which a metal layer is interposed between resin films is used. The metal layer is preferably aluminum foil or aluminum alloy foil in order to reduce the weight. For the resin film, for example, polymeric materials such as polypropylene (PP), polyethylene (PE), nylon and polyethylene terephthalate (PET) can be used. The laminated film can be molded into the shape of the exterior member by sealing by heat fusion. The laminate film preferably has a thickness of 0.2 mm or less.

  The metal container can be formed of aluminum or an aluminum alloy. The aluminum alloy preferably contains elements such as magnesium, zinc and silicon. On the other hand, the content of transition metals such as iron, copper, nickel and chromium is preferably 100 ppm or less. This makes it possible to dramatically improve long-term reliability and heat dissipation under high temperature environments. The thickness of the metal container is preferably 0.5 mm or less, and more preferably 0.2 mm or less.

(Positive terminal)
The positive electrode terminal is formed of a material having electrical stability and conductivity in the range of 3.0 V or more and 4.5 V or less with respect to the lithium ion metal. Examples of the material of the positive electrode terminal include aluminum or an aluminum alloy containing one or more elements selected from Mg, Ti, Zn, Mn, Fe, Cu and Si. The positive electrode terminal is preferably formed of the same material as the positive electrode current collector in order to reduce the contact resistance with the positive electrode current collector.

(Negative terminal)
The negative electrode terminal is formed of a material having electrical stability and conductivity in the range of 1.0 V to 3.0 V with respect to the lithium ion metal. Examples of the material of the negative electrode terminal include aluminum or an aluminum alloy containing one or more elements selected from Mg, Ti, Zn, Mn, Fe, Cu and Si. The negative electrode terminal is preferably formed of the same material as the negative electrode current collector in order to reduce the contact resistance with the negative electrode current collector.

  The nonaqueous electrolyte battery according to the present embodiment is not limited to the configuration shown in FIG. 3 and FIG. 4 described above, and may be, for example, a battery having a configuration shown in FIG. 5 and FIG. FIG. 5 is a partially cutaway perspective view schematically showing another non-aqueous electrolyte battery according to the present embodiment, and FIG. 6 is an enlarged cross-sectional view of a portion B of FIG.

  The non-aqueous electrolyte battery 30 shown in FIGS. 5 and 6 is configured such that the stacked electrode group 31 is accommodated in the exterior material 32. The stacked electrode group 31 has a structure in which the positive electrode 33 and the negative electrode 34 are alternately stacked with the separator 35 interposed therebetween as shown in FIG.

  A plurality of positive electrodes 33 exist, each including a positive electrode current collector 33a and a positive electrode layer 33b supported on both sides of the positive electrode current collector 33a. The positive electrode layer 33 b contains a positive electrode active material.

  A plurality of negative electrodes 34 exist, each including a negative electrode current collector 34 a and a negative electrode layer 34 b supported on both sides of the negative electrode current collector 34 a. The negative electrode layer 34 b contains a negative electrode active material. One side of the negative electrode current collector 34 a of each negative electrode 34 protrudes from the negative electrode 34. The protruding negative electrode current collector 34 a is electrically connected to the strip-shaped negative electrode terminal 36. The tip of the strip-like negative electrode terminal 36 is pulled out from the exterior material 32. Although not shown, the side of the positive electrode current collector 33 a of the positive electrode 33 opposite to the protruding side of the negative electrode current collector 34 a protrudes from the positive electrode 33. The positive electrode current collector 33 a protruding from the positive electrode 33 is electrically connected to the strip-like positive electrode terminal 37. The tip of the strip-like positive electrode terminal 37 is located on the opposite side to the negative electrode terminal 36 and is drawn out from the side of the exterior material 32.

  The materials, blending ratios, dimensions, etc. of the members constituting the non-aqueous electrolyte battery 30 shown in FIGS. 5 and 6 are the same as those of the constituent members of the non-aqueous electrolyte battery 20 described in FIGS. .

  According to the non-aqueous electrolyte battery of the present embodiment described above, since the positive electrode for non-aqueous electrolyte battery of the second embodiment described above is used as the positive electrode, the decrease in discharge capacity at a high discharge rate hardly occurs, and the cycle life Will be longer.

Fourth Embodiment
According to the present embodiment, a battery pack provided with a non-aqueous electrolyte battery is provided. In the present embodiment, the non-aqueous electrolyte battery of the third embodiment described above is used as the non-aqueous electrolyte battery.

  The battery pack of the present embodiment will be described with reference to the drawings. The battery pack has one or more nonaqueous electrolyte batteries (unit cells). When the battery pack has a plurality of unit cells, the unit cells are electrically connected in series or in parallel.

  7 and 8 show an example of a battery pack including a plurality of non-aqueous electrolyte batteries. FIG. 7 is an exploded perspective view of the battery pack. FIG. 7 is a block diagram showing an electric circuit of the battery pack of FIG. In the non-aqueous electrolyte secondary battery pack 40 shown in FIG. 7, the non-aqueous electrolyte battery 20 shown in FIG. 3 is used as the unit cell 41.

  The plurality of unit cells 41 are stacked such that the negative electrode terminal 26 and the positive electrode terminal 27 extended to the outside are aligned in the same direction, and the battery pack 43 is configured by fastening with an adhesive tape 42. These single cells 41 are electrically connected in series to each other as shown in FIGS. 7 and 8.

  The printed wiring board 44 is disposed to face the side surface of the unit cell 41 from which the negative electrode terminal 26 and the positive electrode terminal 27 extend. As shown in FIG. 7, a thermistor 45 (see FIG. 8), a protection circuit 46, and a terminal 47 for energization to an external device are mounted on the printed wiring board 44. An insulating plate (not shown) is attached to the surface of the printed wiring board 44 facing the battery assembly 43 in order to avoid unnecessary connection with the wiring of the battery assembly 43.

  The positive electrode side lead 48 is connected to the positive electrode terminal 27 located in the lowermost layer of the assembled battery 43, and the tip thereof is inserted into the positive electrode side connector 49 of the printed wiring board 44 and electrically connected. The negative electrode side lead 50 is connected to the negative electrode terminal 26 located in the uppermost layer of the assembled battery 43, and the tip thereof is inserted into the negative electrode side connector 51 of the printed wiring board 44 and electrically connected. The positive side connector 49 and the negative side connector 51 are connected to the protective circuit 46 through the wirings 52 and 53 (see FIG. 8) formed on the printed wiring board 44.

  The thermistor 45 is used to detect the temperature of the unit cell 41. Although not shown in FIG. 7, the thermistor 45 is provided in the vicinity of the unit cell 41 and its detection signal is transmitted to the protection circuit 46. . The protection circuit 46 can cut off the plus side wiring 54 a and the minus side wiring 54 b between the protection circuit 46 and the energizing terminal 47 to the external device under predetermined conditions. Here, the above-mentioned predetermined condition is, for example, when the detected temperature of the thermistor 45 becomes equal to or higher than a predetermined temperature. Further, the predetermined condition is when overcharging, overdischarging, overcurrent, etc. of the unit cell 41 is detected. The detection of such overcharge and the like is performed for each single battery 41 or the entire single battery 41. In addition, when detecting the overcharge in each single battery 41 etc., a battery voltage may be detected, and a positive electrode potential or a negative electrode potential may be detected. In the latter case, a lithium electrode used as a reference electrode is inserted into each single battery 41. In the case of FIG. 7 and FIG. 8, wires 55 for voltage detection are connected to each of the single cells 41, and detection signals are transmitted to the protection circuit 46 through the wires 55.

  As shown in FIG. 7, protective sheets 56 made of rubber or resin are respectively disposed on the three side surfaces of the assembled battery 43 except the side surfaces from which the positive electrode terminal 27 and the negative electrode terminal 26 protrude.

  The battery assembly 43 is stored in the storage container 57 together with the protective sheets 56 and the printed wiring board 44. That is, the protective sheet 56 is disposed on both the inner side in the long side direction of the storage container 57 and the inner side in the short side direction, and the printed wiring board 44 is on the inner side opposite to the protective sheet 56 in the short side direction. Be placed. The battery assembly 43 is located in a space surrounded by the protective sheet 56 and the printed wiring board 44. The lid 58 is attached to the upper surface of the storage container 57.

  In order to fix the battery assembly 43, a heat shrink tape may be used instead of the adhesive tape 42. In this case, protective sheets are disposed on both sides of the battery pack, and the heat shrinkable tape is circulated, and then the heat shrinkable tape is heat shrunk to bind the battery pack.

  Here, FIGS. 7 and 8 show a form in which the cells 41 are connected in series, but in order to increase the battery capacity, the cells 41 may be connected in parallel or in parallel with the series connection. The connection may be combined. Moreover, it is also possible to further connect the assembled battery packs in series and in parallel.

  In addition, the aspect of the battery pack is suitably changed according to a use. As the application of the battery pack according to the present embodiment, it is preferable that the battery pack is required to exhibit excellent cycle characteristics when taking out a large current. Specifically, examples include power supplies for digital cameras, and in-vehicle applications such as two-wheel or four-wheel hybrid electric vehicles, two- or four-wheel electric vehicles, and assist bicycles. In particular, the battery pack according to the present embodiment is suitably used for in-vehicle use.

  According to the battery pack of the present embodiment described above, the non-aqueous electrolyte battery according to the third embodiment described above is provided as the non-aqueous electrolyte battery, so the decrease in discharge capacity at a high discharge rate does not easily occur, and the cycle life is short. become longer.

  While certain embodiments of the present invention have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the invention. These embodiments can be implemented in other various forms, and various omissions, replacements, and modifications can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the invention described in the claims and the equivalents thereof as well as included in the scope and the gist of the invention.

  EXAMPLES Examples are described below, but the present invention is not limited to the examples listed below, as long as the gist of the present invention is not exceeded.

Example 1
(Preparation of positive electrode active material)
(1) Preparation of Active Material Particles Coated with Porous Carbonaceous Material Lithium sulfate (Li ₂ SO ₄ ), manganese sulfate pentahydrate (MnSO ₄ · 5 H ₂ O), magnesium sulfate heptahydrate (MgSO ₄ · · · 7H ₂ O), iron sulfate heptahydrate (FeSO ₄ · 7 H ₂ O), diammonium hydrogen phosphate ((NH ₄ ) ₂ HPO ₄ ), sodium carboxymethylcellulose (CMC) in pure water in a nitrogen atmosphere It was dissolved. At this time, the molar ratio of metal, phosphoric acid and CMC dissolved in pure water is 3: 0.85: 0.10: 0.05: 0.1: 0.1 (= Li: Mn: Fe: Mg : PO ₄ : CMC).

The solution in which the above starting material was dissolved was placed in a pressure-resistant vessel, sealed, and subjected to hydrothermal treatment at 200 ° C. for 3 hours while stirring. After hydrothermal treatment, the product was recovered by a centrifugal separator. The recovered product was dried by lyophilization. The dried product was pulverized in ethanol with a planetary ball mill, and then heat-treated at 700 ° C. for 1 hour under an argon atmosphere to obtain active material particles. The obtained active material particles had a composition of LiMn _0.85 Fe _0.10 Mg _0.05 PO ₄ , and the surface was covered with a porous carbonaceous material having pores. In addition, the content of the carbonaceous material with respect to the active material particles was 2.0 mass%.

(2) Filling of a boron-lithium-containing oxide into a porous carbonaceous substance: Dissolving lithium hydroxide (LiOH) and boric acid (H ₃ BO ₃ ) in methanol at a molar ratio of 1: 1 The prepared methanol solution was prepared. The active material is prepared by mixing the prepared methanol solution and the active material particles prepared in the above (1) at a mass ratio of 0.5: 100 of the amount of boron and the amount of active material particles in the methanol solution. A dispersion of particles was prepared. It heat-processed at 80 degreeC, stirring the prepared dispersion liquid, and obtained precursor powder. The obtained precursor powder was calcined at 500 ° C. for 5 hours in an argon atmosphere to fill the porous carbonaceous material on the surface of the active material particles with the boron-lithium-containing oxide to produce a positive electrode active material. .

(Production of positive electrode)
90% by mass of the positive electrode active material prepared as described above, 5% by mass of acetylene black as a conductive agent, 5% by mass of polyvinylidene fluoride (PVdF) as a binder, N-methyl The slurry was prepared by adding to pyrrolidone (NMP) and mixing. The prepared slurry is applied to a current collector made of an aluminum foil having a thickness of 15 μm, dried, and then pressed to have a current collector and a positive electrode active material layer having an electrode density of 1.8 g / cm ^3. The positive electrode was produced.

(Measurement of shift amount of peak angle of (311) plane in interface part of positive electrode active material particles)
The X-ray diffraction pattern (X-ray source: Cu-Kα ray) of the produced positive electrode was measured using the in-plane method and the out-of-plane method. In the measurement of X-ray diffraction by the in-plane method, the incident angle was fixed at 0.8 °, and the measurement time of each step was 0.4 seconds at a step width of 0.02 °. In the measurement of X-ray diffraction by the out-of-plane method, the measurement time of each step was 0.4 seconds at a step width of 0.02 °.
The peak angle (2θ) of the (311) plane of the positive electrode active material particles was measured from the X-ray diffraction patterns obtained by the in-plane method and the out-of-plane method. Then, a value obtained by subtracting the peak angle obtained by the out-of-plane method from the peak angle obtained by the in-plane method was calculated as the shift amount of the peak angle of the (311) plane in the interface portion of the positive electrode active material particles. The results are shown in the column of “shift amount of (311) plane” in Table 1.

(Preparation of tripolar cell)
A three-electrode cell was produced using the produced positive electrode.
For the working electrode, a positive electrode punched into a 2 cm square was used which was crimped to a titanium plate. For the reference electrode and the counter electrode, those obtained by crimping metal lithium to nickel mesh were used. For the separator, a glass filter was used, and for the non-aqueous electrolyte, one in which 1 M of LiPF ₆ was dissolved in EC: DEC = 1: 2 (volume ratio) was used.

(Discharge rate characteristic test)
The three-electrode cell fabricated as described above is charged to 4.25 V at a current value of 0.2 C, and then discharged to 2.5 V at a current value of 0.2 C and 5 C, respectively, and the discharge capacity at that time Was measured. In addition, the electric current value in charging / discharging calculated the capacity | capacitance of active material particle as 150 mAh / g. Also, the test was conducted at a temperature of 25 ° C.
The discharge capacity at the time of discharge at 5 C when the discharge capacity at the time of discharge at 0.2 C was 100% was calculated. The discharge capacity when discharged at 5 C is shown in the column of “Capacitance ratio of 5 C discharge / 0.2 C discharge” in Table 1.

(Cycle characteristic test)
The cycle characteristics of the three-electrode cell fabricated as described above were evaluated at charge and discharge voltage ranges of 4.2 to 3.0 V and a test temperature of 45 ° C. at current values of charge 1 C and discharge 1 C. . In addition, the electric current value in charging / discharging calculated the capacity | capacitance of active material particle as 150 mAh / g. The capacity retention rate after 50 cycles is shown in the column of "capacity retention rate after 50 cycles" in Table 1.

Example 2
In the filling of the boron-lithium-containing oxide in (2) porous carbonaceous material of Example 1, the mass ratio of the amount of boron in the methanol solution to the amount of active material particles of the methanol solution and the active material particles is 1.0. A positive electrode active material was produced in the same manner as in Example 1 except that mixing was performed at an amount ratio of 100: 100.
A positive electrode was produced in the same manner as in Example 1 using the obtained positive electrode active material, and the shift amount of the peak angle of the (311) plane in the interface portion of the positive electrode active material particles was measured. Further, using the obtained positive electrode, a three-pole cell was produced in the same manner as in Example 1, and a discharge rate characteristic test and a cycle characteristic test were conducted. The results are shown in Table 1.

[Example 3]
In the filling of the boron-lithium-containing oxide in (2) porous carbonaceous material of Example 1, the mass ratio of the amount of boron in the methanol solution to the amount of active material particles in the methanol solution is 2.5 A positive electrode active material was produced in the same manner as in Example 1 except that mixing was performed at an amount ratio of 100: 100.
A positive electrode was produced in the same manner as in Example 1 using the obtained positive electrode active material, and the shift amount of the peak angle of the (311) plane in the interface portion of the positive electrode active material particles was measured. Further, using the obtained positive electrode, a three-pole cell was produced in the same manner as in Example 1, and a discharge rate characteristic test and a cycle characteristic test were conducted. The results are shown in Table 1.

Example 4
In the filling of the boron-lithium-containing oxide in (2) the porous carbonaceous material of Example 1, the mass ratio of the amount of boron in the methanol solution to the amount of active material particles is 5.0 A positive electrode active material was produced in the same manner as in Example 1 except that mixing was performed at an amount ratio of 100: 100.
A positive electrode was produced in the same manner as in Example 1 using the obtained positive electrode active material, and the shift amount of the peak angle of the (311) plane in the interface portion of the positive electrode active material particles was measured. Further, using the obtained positive electrode, a three-pole cell was produced in the same manner as in Example 1, and a discharge rate characteristic test and a cycle characteristic test were conducted. The results are shown in Table 1.

[Example 5]
Example 2 is the same as Example 3 except that the molar ratio of lithium hydroxide and boric acid in the methanol solution is 3: 1 in filling the boron-lithium-containing oxide into (2) the porous carbonaceous material of Example 1. Similarly, a positive electrode active material was produced.
A positive electrode was produced in the same manner as in Example 1 using the obtained positive electrode active material, and the shift amount of the peak angle of the (311) plane in the interface portion of the positive electrode active material particles was measured. Further, using the obtained positive electrode, a three-pole cell was produced in the same manner as in Example 1, and a discharge rate characteristic test and a cycle characteristic test were conducted. The results are shown in Table 1.

[Example 6]
In the preparation of (1) porous carbonaceous material-coated active material particles of Example 1, magnesium sulfate heptahydrate was not used, lithium sulfate, manganese sulfate pentahydrate, iron sulfate heptahydrate , Diammonium hydrogen phosphate, sodium carboxymethylcellulose (CMC) in a molar ratio of Li, Mn, Fe, PO ₄ , CMC, 3: 0.7: 0.3: 0.1: 0.05 (= Dissolved in pure water at a ratio of Li: Mn: Fe: PO ₄ : CMC (the composition of the active material particles to be generated is LiMn _0.7 Fe _0.3 PO ₄ , containing carbonaceous material to the active material particles The amount is 1.0% by mass), and further, in the filling of the boron-lithium-containing oxide into (2) porous carbonaceous material of Example 1, the content of boron is 5.0% by mass with respect to the active material particles. More than that The rest was the same as in Example 1 to prepare a positive electrode active material.
A positive electrode was produced in the same manner as in Example 1 using the obtained positive electrode active material, and the shift amount of the peak angle of the (311) plane in the interface portion of the positive electrode active material particles was measured. Further, using the obtained positive electrode, a three-pole cell was produced in the same manner as in Example 1, and a discharge rate characteristic test and a cycle characteristic test were conducted. The results are shown in Table 1.

[Example 7]
30% titanium sulfate aqueous solution was used in place of magnesium sulfate heptahydrate in the preparation of (1) porous carbonaceous material-coated active material particles of Example 1, lithium sulfate, manganese sulfate pentahydrate , Iron sulfate heptahydrate, 30% aqueous solution of titanium sulfate, diammonium hydrogen phosphate, sodium carboxymethylcellulose (CMC) in the molar ratio of Li, Mn, Fe, Ti, PO ₄ , CMC, 3: 0. Dissolved in pure water at a ratio of 86: 0.10: 0.04: 0.1: 0.05 (= Li: Mn: Fe: Ti: PO ₄ : CMC) composition _{LiMn 0.86 Fe 0.10 Ti 0.04 PO 4} , 1.0 wt% content of the carbonaceous material to the active material particles), and (2) boron into porous carbonaceous material - lithium-containing oxide In the filling, the content of boron, except that was set to be 5.0 wt% with respect to the active material particles, to prepare a positive electrode active material in the same manner as in Example 1.
A positive electrode was produced in the same manner as in Example 1 using the obtained positive electrode active material, and the shift amount of the peak angle of the (311) plane in the interface portion of the positive electrode active material particles was measured. Further, using the obtained positive electrode, a three-pole cell was produced in the same manner as in Example 1, and a discharge rate characteristic test and a cycle characteristic test were conducted. The results are shown in Table 1.

[Example 8]
Zinc sulfate heptahydrate was used in place of magnesium sulfate heptahydrate in the preparation of (1) porous carbonaceous material-coated active material particles of Example 1, lithium sulfate, manganese sulfate pentahydrate Hydrate, iron sulfate heptahydrate, zinc sulfate heptahydrate, diammonium hydrogen phosphate, sodium carboxymethylcellulose (CMC) in a molar ratio of Li, Mn, Fe, Zn, PO ₄ , CMC, 3: Dissolved in pure water at a ratio of 0.84: 0.10: 0.06: 0.1: 0.05 (= Li: Mn: Fe: Zn: PO ₄ : CMC) (active material formed) The composition of the particles is LiMn _0.84 Fe _0.10 Zn _0.06 PO ₄ , the content of the carbonaceous matter with respect to the active material particles is 1.0% by mass), and (2) the boron-lithium content in the porous carbonaceous matter For oxide filling Te, the content of boron, except that was made to be 5.0 wt% with respect to the active material particles, to prepare a positive electrode active material in the same manner as in Example 1.
A positive electrode was produced in the same manner as in Example 1 using the obtained positive electrode active material, and the shift amount of the peak angle of the (311) plane in the interface portion of the positive electrode active material particles was measured. Further, using the obtained positive electrode, a three-pole cell was produced in the same manner as in Example 1, and a discharge rate characteristic test and a cycle characteristic test were conducted. The results are shown in Table 1.

Comparative Example 1
A positive electrode active material was produced in the same manner as in Example 1 except that (2) filling of the porous carbonaceous material with a boron-lithium-containing oxide was not performed in Example 1.
A positive electrode was produced in the same manner as in Example 1 using the obtained positive electrode active material, and the shift amount of the peak angle of the (311) plane in the interface portion of the positive electrode active material particles was measured. Further, using the obtained positive electrode, a three-pole cell was produced in the same manner as in Example 1, and a discharge rate characteristic test and a cycle characteristic test were conducted. The results are shown in Table 1.

Comparative Example 2
A positive electrode active material was produced in the same manner as in Example 6 except that (2) the filling of the porous carbonaceous material with the boron-lithium-containing oxide was not performed in Example 6.
A positive electrode was produced in the same manner as in Example 1 using the obtained positive electrode active material, and the shift amount of the peak angle of the (311) plane in the interface portion of the positive electrode active material particles was measured. Further, using the obtained positive electrode, a three-pole cell was produced in the same manner as in Example 1, and a discharge rate characteristic test and a cycle characteristic test were conducted. The results are shown in Table 1.

Comparative Example 3
A positive electrode active material was produced in the same manner as in Example 7 except that (2) the filling of the porous carbonaceous material with the boron-lithium-containing oxide was not performed in Example 7.
A positive electrode was produced in the same manner as in Example 1 using the obtained positive electrode active material, and the shift amount of the peak angle of the (311) plane in the interface portion of the positive electrode active material particles was measured. Further, using the obtained positive electrode, a three-pole cell was produced in the same manner as in Example 1, and a discharge rate characteristic test and a cycle characteristic test were conducted. The results are shown in Table 1.

Comparative Example 4
A positive electrode active material was produced in the same manner as in Example 8 except that (2) the filling of the porous carbonaceous material with the boron-lithium-containing oxide was not performed in Example 8.
A positive electrode was produced in the same manner as in Example 1 using the obtained positive electrode active material, and the shift amount of the peak angle of the (311) plane in the interface portion of the positive electrode active material particles was measured. Further, using the obtained positive electrode, a three-pole cell was produced in the same manner as in Example 1, and a discharge rate characteristic test and a cycle characteristic test were conducted. The results are shown in Table 1.

  From the results in Table 1, it is seen that Examples 1 to 5 and Comparative Example 1, Example 6 and Comparative Example 2, Example 7 and Comparative Example 3, and Example 8 and Comparative Example 4 in which the active material particles have the same composition. In comparison, it can be seen that the capacity ratio of 5 C discharge / 0.2 C discharge is higher and the capacity retention rate after 50 cycles is higher in each of the examples.

[Example 9]
A laminate-type cell was produced using the positive electrode containing the positive electrode active material on the surface of which the film containing the boron-lithium-containing oxide and the carbonaceous material was formed, which was prepared in Example 1.
The preparation of the negative electrode was performed as follows. First, 90% by mass of spinel type titanium oxide powder, 5% by mass of acetylene black and 5% by mass of polyvinylidene fluoride (PVdF) were added to N-methylpyrrolidone (NMP) and mixed to prepare a slurry. The slurry was applied to both sides 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 .

  A positive electrode, a separator made of a polyethylene porous film with a thickness of 25 μm, a negative electrode, and a separator were laminated in this order, and spirally wound. By heat-pressing this at 90 ° C., a flat electrode group having a width of 30 mm and a thickness of 3.0 mm was produced. 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 a 40 μm thick aluminum foil, and the overall thickness is 0.1 mm. The liquid non-aqueous electrolyte was injected into a laminate film pack containing the electrode assembly. Thereafter, the pack was completely sealed by heat sealing, and a non-aqueous electrolyte battery having a width of 35 mm, a thickness of 3.2 mm and a height of 65 mm, which had the structure shown in FIG.

  It is confirmed that the obtained non-aqueous electrolyte battery is unlikely to cause a decrease in discharge capacity at a high discharge rate, and has a long cycle life.

Claims (7)

_{LiMn 1-x-y Fe x} A y PO 4 (A is, Mg, Ca, Al, Ti , Zn and Z
represents at least one element selected from the group consisting of r, and x and y satisfy 0 <x ≦ 0.3
And 0 ≦ y ≦ 0.1)).
A porous carbonaceous material on the surface of the active material particles, and a film containing an oxide containing boron and lithium filled in the porous carbonaceous material;
The thickness of the film is 1 nm or more.
The oxide containing boron and lithium is contained in an amount of 0.5% by mass or more and 5.0% by mass or less with respect to the active material particles as a boron amount,
The positive electrode active material for nonaqueous electrolyte batteries which contains the said carbonaceous material in the quantity of 0.5 mass% or more and 5.0 mass% or less with respect to the said active material particle. In an X-ray diffraction pattern measured by an X-ray diffraction method using Cu-Kα rays, the diffraction angle 2θ of the maximum peak of the (311) plane in the interface portion of the active material particle is in the bulk portion of the active material particle 0.01 ° or more than the diffraction angle 2θ of the maximum peak of the (311) plane,
The positive electrode active material for a non-aqueous electrolyte battery according to claim 1, which is at a high angle in the range of 0.15 ° or less. The positive electrode active material for a non-aqueous electrolyte battery according to claim 1, wherein the thickness of the film is 50 nm or less. Current collector,
A non-water comprising a positive electrode active material for a non-aqueous electrolyte battery according to any one of claims 1 to 3 formed on the current collector, a positive electrode active material layer containing a conductive agent and a binder. Positive electrode for electrolyte battery. A non-aqueous electrolyte battery comprising the positive electrode for a non-aqueous electrolyte battery according to claim 4, a negative electrode, and a non-aqueous electrolyte.   A battery pack comprising the non-aqueous electrolyte battery according to claim 5.   A vehicle comprising the battery pack according to claim 6.

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