JP6988892B2 - Positive electrode active material, positive electrode, battery, battery pack, electronic equipment, electric vehicle, power storage device and power system - Google Patents

Description

The present disclosure relates to positive electrode active materials, positive electrodes, batteries, battery packs, electronic devices, electric vehicles, power storage devices and electric power systems.

Various electronic devices such as mobile phones and personal digital assistants (PDAs) have become widespread, and there is a demand for miniaturization, weight reduction, and long life of the electronic devices. Along with this, as a power source, batteries, particularly small and lightweight secondary batteries capable of obtaining high energy density, are being developed.

The secondary battery is not limited to the above-mentioned electronic devices, and its application to other applications is also being considered. Examples of other uses are battery packs that are detachably mounted on electronic devices and the like, electric vehicles such as electric vehicles, power storage systems such as household power servers, and power tools such as electric drills.

The secondary battery includes an electrolytic solution together with a positive electrode and a negative electrode, and the positive electrode thereof contains a positive electrode active material. Since the composition of the positive electrode active material has a great influence on the battery characteristics, various studies have been made on the positive electrode active material.

Specifically, various methods have been studied for the purpose of improving the characteristics such as suppressing the increase in resistance and improving the cycle characteristics. Patent Document 1 and Non-Patent Documents 1 and 2 describe a technique for modifying the particle surface as a typical method thereof.

Japanese Unexamined Patent Publication No. 2011-129948

J. Cho, Y. J. Kim, T. J. Kim, B. Park, Angew. Chem. Int. Ed., 40, 3367 (2001) Y. J. Kim, J. Cho, T. J. Kim, B. Park, J. Electrochem. Soc., 150, A1723 (2003)

The above-mentioned electronic devices and the like are becoming more and more sophisticated and multifunctional, and their frequency of use is increasing, so that secondary batteries tend to be charged and discharged frequently. Therefore, further improvement in cycle characteristics is desired.

An object of the present disclosure is to provide a positive electrode active material, a positive electrode, a battery, a battery pack including the positive electrode, an electronic device, an electric vehicle, a power storage device, and an electric power system capable of improving cycle characteristics.

In order to solve the above-mentioned problems, the battery of the present disclosure comprises a positive electrode containing powder of positive electrode active material particles, a negative electrode, and an electrolyte, and the positive electrode active material particles are made of lithium cobaltate and cobalt of lithium cobaltate. It contains at least one of those partially substituted with other metal elements, and the surface of the positive electrode active material particles is in a state of lacking oxygen as compared with the inside of the positive electrode active material particles, and has a hardness of 7.94 keV. When the spectrum of the O1s orbital of the surface of the positive electrode active material particles was measured by hard X-ray photoelectron spectroscopy using X-rays, peaks were shown in the region A with a coupling energy of 528 eV or more and 532 eV or less and the region B of more than 532 eV and 536 eV or less. , regions a, the maximum intensity of the peak in each region B _I a, when the _{I B,} the peak intensity ratio _I a / _{I B} satisfies the relation of _{1.4 ≦ I a / I B <} 2.5 ..

The positive electrode active material of the present disclosure contains powder of positive electrode active material particles, and the positive electrode active material particles are at least one of lithium cobaltate and a part of cobalt of lithium cobaltate substituted with other metal elements. The surface of the positive electrode active material particles is in a state of lacking oxygen as compared with the inside of the positive electrode active material particles, and the positive electrode active material particles are subjected to hard X-ray photoelectron spectroscopy using a hard X-ray of 7.94 keV. When the spectrum of the O1s orbital on the surface was measured, peaks were shown in the region A of the coupling energy of 528 eV or more and 532 eV or less and the region B of more than 532 eV and 536 eV or less, and the maximum intensities of the peaks in each of the region A and the region B were I _A and I. when is _B, the peak intensity ratio _I a / _{I B} satisfies the relation of _{1.4 ≦ I a / I B <} 2.5.

The positive electrode of the present disclosure contains powder of positive electrode active material particles, and the positive electrode active material particles include at least one of lithium cobaltate and a part of cobalt of lithium cobaltate substituted with other metal elements. The surface of the positive electrode active material particles is in a state of lacking oxygen as compared with the inside of the positive electrode active material particles, and the surface of the positive electrode active material particles is subjected to hard X-ray photoelectron spectroscopy using a hard X-ray of 7.94 keV. shows a peak at 536eV following areas B exceeds the binding energy 528eV least 532eV following areas a and 532eV when measured spectra of O1s orbit region a, the maximum intensity of the peak in each region B _I a, and _{I B} when the peak intensity ratio _I a / _{I B} satisfies the relation of _{1.4 ≦ I a / I B <} 2.5.

The battery packs, electronic devices, electric vehicles, power storage devices and power systems of the present disclosure include the above-mentioned batteries.

According to the present disclosure, the cycle characteristics of the battery can be improved. The effects described herein are not necessarily limited, and may be any of the effects described in the present disclosure or an effect different from them.

It is sectional drawing which shows an example of the structure of the positive electrode active material which concerns on the modification of 1st Embodiment of this disclosure. It is sectional drawing which shows an example of the structure of the non-aqueous electrolyte secondary battery which concerns on 2nd Embodiment of this disclosure. It is sectional drawing which shows the part of the winding type electrode body shown in FIG. 2 in an enlarged manner. It is an exploded perspective view which shows an example of the structure of the non-aqueous electrolyte secondary battery which concerns on 3rd Embodiment of this disclosure. It is sectional drawing along the VV line of FIG. It is a block diagram which shows an example of the structure of the electronic device as an application example. It is a schematic diagram which shows an example of the structure of the power storage system in a vehicle as an application example. It is a schematic diagram which shows an example of the structure of the power storage system in a house as an application example.

The embodiments and application examples of the present disclosure will be described in the following order.
1 First embodiment (example of positive electrode active material)
2 Second embodiment (example of cylindrical battery)
3 Third embodiment (example of laminated film type battery)
4 Application example 1 (example of battery pack and electronic device)
5 Application example 2 (Example of power storage system in a vehicle)
6 Application example 3 (Example of power storage system in a house)

<1 First Embodiment>
[Composition of positive electrode active material]
The positive electrode active material according to the first embodiment of the present disclosure is a so-called positive electrode active material for a non-aqueous electrolyte secondary battery, and contains powder of positive electrode active material particles. The positive electrode active material particles can occlude and release lithium (Li), which is an electrode reactant, and contain a lithium transition metal composite oxide having a layered rock salt type structure. The positive electrode active material according to the first embodiment is a non-aqueous electrolyte secondary electricity having a high charging voltage (for example, a non-aqueous electrolyte secondary electricity having a positive electrode potential of 4.40 V (vsLi / Li ⁺ ) or more in a fully charged state). It is suitable for application to.

More specifically, the powder of the positive electrode active material particles has crystalline properties, and lithium cobalt oxide and a part of cobalt (Co) of lithium cobalt oxide are substituted with other metal elements (hereinafter, "cobalt acid"). It contains at least one of the "replacements of lithium"). When the powder of the positive electrode active material particles contains a lithium cobalt oxide substituent, the content of other metal elements in the lithium cobalt oxide substituent is higher than, for example, the content of cobalt in the lithium cobalt oxide substituted. few. Other metal elements are magnesium (Mg), aluminum (Al), boron (B), titanium (Ti), yttrium (V), chromium (Cr), iron (Fe), copper (Cu), zinc (Zn). , Molybdenum (Mo), Tin (Sn), Titanium (W), Zirconium (Zr), Yttrium (Y), Niob (Nb), Calcium (Ca), Strontium (Sr), Bismus (Bi), Sodium (Na) , Potassium (K), silicon (Si) and phosphorus (P).

The powder of the positive electrode active material particles preferably has an average composition represented by the following formula (1).
_{Li x Co 1-y M y} O 2-z ··· (1)
(M is of magnesium, aluminum, boron, titanium, vanadium, chromium, iron, copper, zinc, molybdenum, tin, tungsten, zirconium, yttrium, niobium, calcium, strontium, bismuth, sodium, potassium, silicon and phosphorus. At least one kind. X, y and z satisfy 0 ≦ x ≦ 1, 0 ≦ y <0.5 and −0.1 ≦ z ≦ 0.2. The composition of lithium is in a charged / discharged state. The value of x represents the value in the fully discharged state.)

The surface of the positive electrode active material particles is in a state of lacking oxygen as compared with the inside of the positive electrode active material particles. The concentration of oxygen deficiency may change rapidly from the surface of the positive electrode active material particles toward the inside of the positive electrode active material particles in a stepwise manner, or may gradually change.

The positive electrode active material particles are bound when the spectrum of the O1s orbital on the surface of the positive positive material active material particles is measured by hard X-ray Photoelectron Spectroscopy (HAXPES) using hard X-rays of 7.94 keV. Peaks are shown in the region A having an energy of 528 eV or more and 532 eV or less and the region B having an energy of more than 532 eV and 536 eV or less. Further, when the maximum intensities of the peaks in the regions A and B are I _A and I _B , the peak intensity ratio I _A / I _B is I _A / I _B <2.5, preferably 1.4 ≦. It satisfies the relationship of _{I A} / I _B <2.5, more preferably 1.4 ≤ I _A / I _{B ≤ 2.}

The maximum intensity I _{A of the} peak indicates the state of oxygen in the crystal near the surface of the positive electrode active material particles, and the _{larger the I A} , the more oxygen in the crystal near the surface of the positive electrode active material particles. On the other hand, the maximum intensity I _B of a peak indicates a state of oxygen deficiency in the vicinity of the surface of the positive electrode active material particle, the greater the oxygen deficiency in the vicinity of the surface of more positive electrode active material particles are larger I _B.

When the peak intensity ratio I _A / I _B is 2.5 ≦ I _A / I _B , the oxygen in the crystal near the surface of the positive electrode active material particles increases too much, and the crystallinity near the surface of the positive electrode active material particles is high. Too much. Therefore, the strain of the lattice and crystallites near the surface of the positive electrode active material particles caused by the Li insertion / desorption reaction accompanied by the phase transition cannot be relaxed, and the cycle characteristics may deteriorate. On the other hand, when the peak intensity ratio I _A / I _B is I _A / I _B <1.4, the oxygen in the crystal near the surface of the positive electrode active material particles decreases too much, and the crystallinity near the surface of the positive positive material particles decreases too much. Is too low, the binding of Co-O is disturbed, and the binding force of Co-O is lowered. Therefore, during high-temperature storage, there is a risk that metals such as cobalt may easily elute from the positive electrode active material particles due to diffusion in the solid.

HAXPES is an X-ray photoelectron spectroscopy (XPS) that uses high-energy X-rays, and because it has a deeper detection depth than general-purpose XPS, it is possible to analyze the chemical state of the buried interface inside. It is possible. The oxygen-bonded state confirmed by the general-purpose XPS is the state of the outermost surface of the positive electrode active material particles at several nm, and it is difficult to confirm the oxygen-bonded state in the crystal lattice with the general-purpose XPS.

[effect]
The positive electrode active material according to the first embodiment contains at least one of lithium cobalt oxide and a substituted material of lithium cobalt oxide, and is used for positive electrode activity by hard X-ray photoelectron spectroscopy using 7.94 keV hard X-rays. When the spectrum of the O1s orbital on the surface of the material particles is measured, peaks are shown in the region A having a coupling energy of 528 eV or more and 532 eV or less and the region B having a binding energy of more than 532 eV and 536 eV or less. Further, when the maximum intensities of the peaks in the regions A and B are I _A and I _B , the peak intensity ratio I _A / I _B satisfies the relationship of I _A / I _{B <2.5.} This makes it possible to define the properties near the particle surface that greatly affect the battery performance. That is, it is possible to set the chemical bond state of oxygen in the vicinity of the surface of the positive electrode active material particles to a specified state that can improve the cycle characteristics.

[Modification example]
As shown in FIG. 1, the positive electrode active material particles may be surface-coated composite particles including the core particles 1 and the coating layer 2 that covers at least a part of the surface of the core particles 1.

The core particles 1 are positive electrode active material particles according to the first embodiment. The coating layer 2 may partially cover the surface of the core particles 1 or may cover the entire surface of the core particles 1, but from the viewpoint of improving the cycle characteristics, the coating layer 2 may cover the entire surface of the core particles 1. It is preferable to cover the entire surface. At the interface between the core particles 1 and the coating layer 2, the composition and state of both may change discontinuously or continuously.

The coating layer 2 includes, for example, lithium, nickel (Ni), manganese (Mn), magnesium, aluminum, boron, titanium, vanadium, chromium, iron, cobalt, copper, zinc, molybdenum, tin, tungsten, zirconium, and the like. Includes oxides containing at least one element of the group consisting of yttrium, niobium, calcium and strontium. From the viewpoint of improving the cycle characteristics, the coating layer 2 preferably contains an oxide containing lithium, nickel, and manganese.

When the above-mentioned surface-coated composite particles are used as the positive electrode active material particles, the cycle characteristics of the battery can be further improved.

The positive electrode active material may further contain powders of other positive electrode active material particles in addition to the powder of the positive electrode active material particles in the first embodiment. For example, in addition to the powder of the positive electrode active material particles in the first embodiment, the powder of the positive electrode active material particles (surface-coated composite particles) in the above-mentioned modified example may be further contained.

<2 Second Embodiment>
In the second embodiment, the non-aqueous electrolyte secondary battery including the positive electrode containing the positive electrode active material according to the first embodiment described above will be described.

[Battery configuration]
Hereinafter, a configuration example of a non-aqueous electrolyte secondary battery (hereinafter, simply referred to as “battery”) according to the second embodiment of the present disclosure will be described with reference to FIG. This battery is, for example, a so-called lithium ion secondary battery in which the capacity of the negative electrode is represented by a capacity component due to occlusion and release of lithium, which is an electrode reactant. This battery is a so-called cylindrical type, and a pair of strip-shaped positive electrodes 21 and strip-shaped negative electrodes 22 are laminated and wound inside a substantially hollow cylindrical battery can 11 via a separator 23. It has a mold electrode body 20. The battery can 11 is made of nickel-plated iron, one end of which is closed and the other end of which is open. An electrolytic solution as a liquid electrolyte is injected into the inside of the battery can 11 and impregnated into the positive electrode 21, the negative electrode 22 and the separator 23. Further, a pair of insulating plates 12 and 13 are arranged perpendicular to the winding peripheral surface so as to sandwich the winding type electrode body 20.

At the open end of the battery can 11, a battery lid 14, a safety valve mechanism 15 provided inside the battery lid 14, and a heat-sensitive temperature coefficient (PTC element) 16 are interposed via a sealing gasket 17. It is attached by being crimped. As a result, the inside of the battery can 11 is sealed. The battery lid 14 is made of, for example, the same material as the battery can 11. The safety valve mechanism 15 is electrically connected to the battery lid 14, and when the internal pressure of the battery exceeds a certain level due to an internal short circuit or external heating, the disk plate 15A is inverted and wound around the battery lid 14. The electrical connection with the rotary electrode body 20 is cut off. The sealing gasket 17 is made of, for example, an insulating material, and the surface thereof is coated with asphalt.

For example, a center pin 24 is inserted in the center of the wound electrode body 20. A positive electrode lead 25 made of aluminum or the like is connected to the positive electrode 21 of the wound electrode body 20, and a negative electrode lead 26 made of nickel or the like is connected to the negative electrode 22. The positive electrode lead 25 is electrically connected to the battery lid 14 by being welded to the safety valve mechanism 15, and the negative electrode lead 26 is welded to the battery can 11 and electrically connected.

Hereinafter, the positive electrode 21, the negative electrode 22, the separator 23, and the electrolytic solution constituting the battery will be sequentially described with reference to FIG.

(Positive electrode)
The positive electrode 21 has, for example, a structure in which positive electrode active material layers 21B are provided on both sides of the positive electrode current collector 21A. Although not shown, the positive electrode active material layer 21B may be provided on only one side of the positive electrode current collector 21A. The positive electrode current collector 21A is made of, for example, a metal foil such as an aluminum foil, a nickel foil, or a stainless steel foil. The positive electrode active material layer 21B contains a positive electrode active material. The positive electrode active material layer 21B may further contain at least one of a conductive agent and a binder, if necessary.

(Positive electrode active material)
The positive electrode active material is the positive electrode active material according to the first embodiment.

(Binder)
Examples of the binder include resin materials such as polyvinylidene fluoride (PVdF), polytetrafluoroethylene (PTFE), polyacrylonitrile (PAN), styrene butadiene rubber (SBR) and carboxymethyl cellulose (CMC), and resins thereof. At least one selected from a material-based copolymer and the like is used.

(Conducting agent)
Examples of the conductive agent include carbon materials such as graphite, carbon fiber, carbon black, Ketjen black or carbon nanotubes, and one of these may be used alone or two or more thereof may be mixed. May be used. Further, in addition to the carbon material, a metal material, a conductive polymer material, or the like may be used as long as it is a conductive material.

(Negative electrode)
The negative electrode 22 has, for example, a structure in which the negative electrode active material layers 22B are provided on both sides of the negative electrode current collector 22A. Although not shown, the negative electrode active material layer 22B may be provided on only one side of the negative electrode current collector 22A. The negative electrode current collector 22A is made of, for example, a metal foil such as a copper foil, a nickel foil, or a stainless steel foil.

The negative electrode active material layer 22B contains one or more negative electrode active materials capable of occluding and releasing lithium. The negative electrode active material layer 22B may further contain at least one of a binder and a conductive agent, if necessary.

In this battery, the electrochemical equivalent of the negative electrode 22 or the negative electrode active material is larger than the electrochemical equivalent of the positive electrode 21, and theoretically, lithium metal does not precipitate on the negative electrode 22 during charging. It is preferable to have.

(Negative electrode active material)
Examples of the negative electrode active material include non-graphitizable carbon, easily graphitizable carbon, graphite, pyrolytic carbons, cokes, glassy carbons, calcined organic polymer compounds, carbon fibers, and carbon materials such as activated carbon. Can be mentioned. Among these, coke includes pitch coke, needle coke, petroleum coke and the like. An organic polymer compound calcined body is a material obtained by calcining a polymer material such as a phenol resin or a furan resin at an appropriate temperature to carbonize it, and a part of it is non-graphitizable carbon or easily graphitizable carbon. Some are classified as. These carbon materials are preferable because the change in the crystal structure that occurs during charging / discharging is very small, a high charging / discharging capacity can be obtained, and good cycle characteristics can be obtained. In particular, graphite is preferable because it has a large electrochemical equivalent and can obtain a high energy density. Further, graphitizable carbon is preferable because excellent cycle characteristics can be obtained. Furthermore, those having a low charge / discharge potential, specifically those having a charge / discharge potential close to that of lithium metal, are preferable because high energy density of the battery can be easily realized.

Further, as another negative electrode active material capable of increasing the capacity, a material containing at least one of a metal element and a metalloid element as a constituent element (for example, an alloy, a compound or a mixture) can be mentioned. This is because a high energy density can be obtained by using such a material. In particular, when used together with a carbon material, high energy density can be obtained and excellent cycle characteristics can be obtained, which is more preferable. In the present disclosure, in addition to alloys composed of two or more kinds of metal elements, alloys including one or more kinds of metal elements and one or more kinds of metalloid elements are also included. It may also contain non-metal elements. Some of the structures include solid solutions, eutectics (eutectic mixtures), intermetallic compounds, or two or more of them coexist.

Examples of such a negative electrode active material include a metal element or a metalloid element capable of forming an alloy with lithium. Specifically, magnesium, boron, aluminum, titanium, gallium (Ga), indium (In), silicon, germanium (Ge), tin, lead (Pb), bismuth, cadmium (Cd), silver (Ag), zinc. , Hafnium (Hf), zirconium, indium, palladium (Pd) or platinum (Pt). These may be crystalline or amorphous.

The negative electrode active material preferably contains a metal element or a metalloid element of Group 4B in the short periodic table as a constituent element, and more preferably contains at least one of silicon and tin as a constituent element. This is because silicon and tin have a large ability to occlude and release lithium, and a high energy density can be obtained. Examples of such a negative electrode active material include simple substances of silicon, alloys or compounds, simple substances of tin, alloys or compounds, and materials having at least one or more phases thereof.

The silicon alloy includes, for example, tin, nickel, copper, iron, cobalt, manganese, zinc, indium, silver, titanium, germanium, bismuth, antimony (Sb) and chromium as the second constituent element other than silicon. Included are those containing at least one of the groups. As a tin alloy, for example, as a second constituent element other than tin, among the group consisting of silicon, nickel, copper, iron, cobalt, manganese, zinc, indium, silver, titanium, germanium, bismuth, antimony and chromium. Those containing at least one of the above are mentioned.

Examples of the compound of tin or the compound of silicon include those containing oxygen or carbon, and may contain the above-mentioned second constituent element in addition to tin or silicon.

Among them, the Sn-based negative electrode active material contains cobalt, tin, and carbon as constituent elements, and the carbon content is 9.9% by mass or more and 29.7% by mass or less, and tin and cobalt are used. A SnCoC-containing material having a cobalt content of 30% by mass or more and 70% by mass or less with respect to the total amount of cobalt is preferable. This is because a high energy density can be obtained in such a composition range and excellent cycle characteristics can be obtained.

This SnCoC-containing material may further contain other constituent elements, if necessary. As other constituent elements, for example, silicon, iron, nickel, chromium, indium, niobium, germanium, titanium, molybdenum, aluminum, phosphorus, gallium or bismuth are preferable, and two or more thereof may be contained. This is because the capacity or cycle characteristics can be further improved.

The SnCoC-containing material has a phase containing tin, cobalt, and carbon, and it is preferable that this phase has a low crystallinity or an amorphous structure. Further, in this SnCoC-containing material, it is preferable that at least a part of carbon which is a constituent element is bonded to a metal element or a metalloid element which is another constituent element. It is considered that the deterioration of the cycle characteristics is due to the aggregation or crystallization of tin or the like, but such aggregation or crystallization can be suppressed by binding carbon to other elements. ..

Examples of the measuring method for investigating the bonding state of elements include X-ray photoelectron spectroscopy (XPS). In XPS, the peak of the 1s orbital (C1s) of carbon appears at 284.5 eV in an energy calibrated device such that if graphite, the peak of the 4f orbital (Au4f) of the gold atom is obtained at 84.0 eV. .. Further, if it is a surface-contaminated carbon, it appears at 284.8 eV. On the other hand, when the charge density of the carbon element is high, for example, when carbon is bonded to a metal element or a metalloid element, the peak of C1s appears in a region lower than 284.5 eV. That is, when the peak of the synthetic wave of C1s obtained for the SnCoC-containing material appears in a region lower than 284.5 eV, at least a part of the carbon contained in the SnCoC-containing material is a metal element or a metalloid which is another constituent element. It is bound to a metal element.

In XPS measurement, for example, the peak of C1s is used to correct the energy axis of the spectrum. Normally, surface-contaminated carbon is present on the surface, so the peak of C1s of the surface-contaminated carbon is set to 284.8 eV, and this is used as the energy standard. In the XPS measurement, the waveform of the C1s peak is obtained as a form including the peak of surface-contaminated carbon and the peak of carbon in the SnCoC-containing material. Therefore, surface contamination is obtained by analysis using, for example, commercially available software. The carbon peak is separated from the carbon peak in the SnCoC-containing material. In the waveform analysis, the position of the main peak existing on the lowest binding energy side is set as the energy reference (284.8 eV).

Other negative electrode active materials include, for example, metal oxides or polymer compounds capable of occluding and releasing lithium. Examples of the metal oxide _{include lithium titanium oxide containing titanium and lithium such as lithium titanate (Li 4} Ti ₅ O ₁₂ ), iron oxide, ruthenium oxide or molybdenum oxide. Examples of the polymer compound include polyacetylene, polyaniline and polypyrrole.

(Binder)
As the binder, for example, at least one selected from resin materials such as polyvinylidene fluoride, polytetrafluoroethylene, polyacrylonitrile, styrene butadiene rubber and carboxymethyl cellulose, and copolymers mainly composed of these resin materials. Is used.

(Conducting agent)
Examples of the conductive agent include carbon materials such as graphite, carbon fiber, carbon black, Ketjen black or carbon nanotubes, and one of these may be used alone or two or more thereof may be mixed. May be used. Further, in addition to the carbon material, a metal material, a conductive polymer material, or the like may be used as long as it is a conductive material.

(Separator)
The separator 23 separates the positive electrode 21 and the negative electrode 22 and allows lithium ions to pass through while preventing a short circuit of current due to contact between the two electrodes. The separator 23 is made of, for example, a porous film made of a resin such as polytetrafluoroethylene, polypropylene, or polyethylene, and may have a structure in which two or more of these porous films are laminated. Above all, the porous film made of polyolefin is preferable because it has an excellent short-circuit prevention effect and can improve the safety of the battery by the shutdown effect. In particular, polyethylene is preferable as a material constituting the separator 23 because it can obtain a shutdown effect in the range of 100 ° C. or higher and 160 ° C. or lower and is also excellent in electrochemical stability. In addition, a material obtained by copolymerizing or blending a resin having chemical stability with polyethylene or polypropylene can be used. Alternatively, the porous membrane may have a structure of three or more layers in which a polypropylene layer, a polyethylene layer, and a polypropylene layer are sequentially laminated.

The separator 23 may have a structure including a base material and a surface layer provided on one side or both sides of the base material. The surface layer contains inorganic particles having an electrically insulating property and a resin material that binds the inorganic particles to the surface of the base material and also binds the inorganic particles to each other. This resin material may have, for example, a three-dimensional network structure in which fibrils are formed and the fibrils are continuously connected to each other. By being supported on the resin material having this three-dimensional network structure, the inorganic particles can maintain a dispersed state without being connected to each other. Further, the resin material may be bonded to the surface of the base material or the inorganic particles without being made into fibril. In this case, higher binding properties can be obtained. By providing the surface layer on one side or both sides of the base material as described above, oxidation resistance, heat resistance and mechanical strength can be imparted to the base material.

The base material is a porous layer having porosity. More specifically, the base material is a porous membrane composed of an insulating membrane having a large ion permeability and a predetermined mechanical strength, and the electrolytic solution is held in the pores of the base material. It is preferable that the base material has a predetermined mechanical strength as a main part of the separator, but has high resistance to an electrolytic solution, low reactivity, and resistance to expansion.

As the resin material constituting the base material, for example, a polyolefin resin such as polypropylene or polyethylene, an acrylic resin, a styrene resin, a polyester resin, a nylon resin, or the like is preferably used. In particular, polyethylene such as low-density polyethylene, high-density polyethylene and linear polyethylene, or their low-molecular-weight wax components, or polyolefin resins such as polypropylene are preferably used because they have an appropriate melting temperature and are easily available. Further, a structure in which these two or more kinds of porous films are laminated, or a porous film formed by melt-kneading two or more kinds of resin materials may be used. Those containing a porous film made of a polyolefin resin have excellent separability between the positive electrode 21 and the negative electrode 22, and can further reduce the decrease in internal short circuit.

As the base material, a non-woven fabric may be used. As the fiber constituting the non-woven fabric, aramid fiber, glass fiber, polyolefin fiber, polyethylene terephthalate (PET) fiber, nylon fiber and the like can be used. Further, these two or more kinds of fibers may be mixed to form a nonwoven fabric.

Inorganic particles include at least one such as metal oxides, metal nitrides, metal carbides and metal sulfides. Metal oxides include aluminum oxide (alumina, Al ₂ O ₃ ), boehmite (hydrated aluminum oxide), magnesium oxide (magnesia, MgO), titanium oxide (titania, TiO ₂ ), zirconium oxide (zirconia, ZrO _2). ), Silicon oxide (silica, SiO ₂ ), yttrium oxide (itria, Y ₂ O ₃ ) and the like can be preferably used. As the metal nitride, silicon nitride (Si ₃ N ₄ ), aluminum nitride (AlN), boron nitride (BN), titanium nitride (TiN) and the like can be preferably used. As the metal carbide, silicon carbide (SiC), boron carbide (B4C) or the like can be preferably used. As the metal sulfide, barium sulfate (BaSO ₄ ) or the like can be preferably used. In addition, _{porous aluminosilicates such as zeolite (M 2 / n} O, Al ₂ O ₃ , xSiO ₂ , yH ₂ O, M is a metal element, x ≧ 2, y ≧ 0), layered silicate, and barium titanate. Minerals such as barium (BaTIO ₃ ) or strontium titanate (SrTiO ₃ ) may be used. Of these, alumina, titania (particularly those having a rutile-type structure), silica or magnesia are preferably used, and alumina is more preferable. The inorganic particles have oxidation resistance and heat resistance, and the surface layer on the side surface facing the positive electrode containing the inorganic particles has strong resistance to the oxidizing environment in the vicinity of the positive electrode during charging. The shape of the inorganic particles is not particularly limited, and any of spherical, plate-like, fibrous, cubic and random shapes can be used.

Examples of the resin material constituting the surface layer include fluororesins such as polyvinylidene fluoride and polytetrafluoroethylene, fluororubber containing vinylidene fluoride-tetrafluoroethylene copolymer, and fluororubber such as ethylene-tetrafluoroethylene copolymer, and styrene. -Butadiene copolymer or its hydride, acrylonitrile-butadiene copolymer or its hydride, acrylonitrile-butadiene-styrene copolymer or its hydride, methacrylic acid ester-acrylic acid ester copolymer, styrene-acrylic acid ester Copolymers, acrylonitrile-acrylic acid ester copolymers, rubbers such as ethylene propylene rubber, polyvinyl alcohol, vinyl acetate, cellulose derivatives such as ethyl cellulose, methyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, polyphenylene ether, polysulfone, polyether sulfone , Polyphenylene sulfide, polyetherimide, polyimide, polyamide such as total aromatic polyamide (aramid), polyamideimide, polyacrylonitrile, polyvinyl alcohol, polyether, acrylic acid resin or polyester, etc. Examples thereof include resins having high heat resistance of ℃ or higher. These resin materials may be used alone or in combination of two or more. Among them, a fluororesin such as polyvinylidene fluoride is preferable from the viewpoint of oxidation resistance and flexibility, and aramid or polyamide-imide is preferably contained from the viewpoint of heat resistance.

The particle size of the inorganic particles is preferably in the range of 1 nm to 10 μm. If it is smaller than 1 nm, it is difficult to obtain it, and even if it can be obtained, it is not worth the cost. On the other hand, if it is larger than 10 μm, the distance between the electrodes becomes large, the amount of active material filled cannot be sufficiently obtained in a limited space, and the battery capacity becomes low.

As a method for forming the surface layer, for example, a slurry composed of a matrix resin, a solvent and an inorganic substance is applied onto a base material (porous film), and the matrix resin is passed through a poor solvent and a parent solvent bath of the above solvent to form a phase. A method of separating and then drying can be used.

The above-mentioned inorganic particles may be contained in a porous membrane as a base material. Further, the surface layer may not contain inorganic particles and may be composed only of a resin material.

(Electrolytic solution)
The separator 23 is impregnated with an electrolytic solution which is a liquid electrolyte. The electrolytic solution contains a solvent and an electrolyte salt dissolved in the solvent. The electrolytic solution may contain known additives in order to improve the battery characteristics.

As the solvent, a cyclic carbonate ester such as ethylene carbonate or propylene carbonate can be used, and it is preferable to use one or a mixture of ethylene carbonate and propylene carbonate in particular. This is because the cycle characteristics can be improved.

As the solvent, in addition to these cyclic carbonate esters, it is preferable to mix and use a chain carbonate ester such as diethyl carbonate, dimethyl carbonate, ethylmethyl carbonate or methylpropyl carbonate. This is because high ionic conductivity can be obtained.

The solvent preferably further contains 2,4-difluoroanisole or vinylene carbonate. This is because 2,4-difluoroanisole can improve the discharge capacity, and vinylene carbonate can improve the cycle characteristics. Therefore, it is preferable to mix and use these because the discharge capacity and the cycle characteristics can be improved.

In addition to these, as solvents, butylene carbonate, γ-butyrolactone, γ-valerolactone, 1,2-dimethoxyethane, tetrahydrofuran, 2-methyltransferase, 1,3-dioxolane, 4-methyl-1,3- Dioxolane, Methyl Acetate, Methyl Propionate, acetonitrile, Glutaronitrile, Adiponitrile, methoxynitrile, 3-methoxypropyronitrile, N, N-dimethylformamide, N-methylpyrrolidinone, N-methyloxazolidinone, N, N-dimethyl Examples thereof include imidazolidinone, nitromethane, nitroethane, sulfolane, dimethylsulfoxide, trimethyl phosphate and the like.

It should be noted that a compound in which at least a part of hydrogen in these non-aqueous solvents is replaced with fluorine may be preferable because the reversibility of the electrode reaction may be improved depending on the type of the electrode to be combined.

Examples of the electrolyte salt include lithium salts, and one type may be used alone or two or more types may be mixed and used. Lithium salts include LiPF ₆ , LiBF ₄ , _{LiAsF 6} , LiClO ₄ , LiB (C ₆ H ₅ ) ₄ , LiCH ₃ SO ₃ , LiCF ₃ SO ₃ , LiN (SO ₂ CF ₃ ) ₂ , LiC (SO ₂ CF). ₃ ) ₃ , LiAlCl ₄ , LiSiF ₆ , LiCl, difluoro [oxorat-O, O'] lithium borate, lithium bisoxalate volate, LiBr and the like can be mentioned. Above all, LiPF ₆ is preferable because it can obtain high ionic conductivity and improve cycle characteristics.

[Positive potential]
The positive electrode potential (vsLi / Li ⁺ ) in the fully charged state preferably exceeds 4.20 V, more preferably 4.25 V or more, still more preferably more than 4.40 V, and particularly preferably 4.45 V or more, most preferably. Is 4.50V or higher. However, the positive electrode potential ( ^{vsLi / Li +} ) in the fully charged state may be 4.20 V or less. The upper limit of the positive electrode potential (vsLi / Li ⁺ ) in the fully charged state is not particularly limited, but is preferably 6.00 V or less, more preferably 5.00 V or less, and even more preferably 4.80 V or less. Particularly preferably, it is 4.70 V or less.

[Battery operation]
In the battery having the above configuration, when charging is performed, lithium ions are released from the positive electrode active material layer 21B and are occluded in the negative electrode active material layer 22B via the electrolytic solution. Further, when the electric discharge is performed, lithium ions are released from the negative electrode active material layer 22B and are occluded in the positive electrode active material layer 21B via the electrolytic solution.

[Battery manufacturing method]
Next, an example of a battery manufacturing method according to the second embodiment of the present disclosure will be described.

First, for example, a positive electrode mixture is prepared by mixing the positive electrode active material according to the first embodiment, a conductive agent, and a binder, and the positive electrode mixture is used as N-methyl-2-pyrrolidone (NMP). To prepare a paste-like positive electrode mixture slurry by dispersing it in a solvent such as. Next, this positive electrode mixture slurry is applied to the positive electrode current collector 21A, the solvent is dried, and the positive electrode active material layer 21B is formed by compression molding with a roll press machine or the like to form the positive electrode 21.

Further, for example, a negative electrode mixture is prepared by mixing a negative electrode active material and a binder, and this negative electrode mixture is dispersed in a solvent such as N-methyl-2-pyrrolidone to form a paste-like negative electrode mixture slurry. To make. Next, this negative electrode mixture slurry is applied to the negative electrode current collector 22A, the solvent is dried, and compression molding is performed by a roll press machine or the like to form the negative electrode active material layer 22B, and the negative electrode 22 is manufactured.

Next, the positive electrode lead 25 is attached to the positive electrode current collector 21A by welding or the like, and the negative electrode lead 26 is attached to the negative electrode current collector 22A by welding or the like. Next, the positive electrode 21 and the negative electrode 22 are wound around the separator 23. Next, the tip of the positive electrode lead 25 is welded to the safety valve mechanism 15, the tip of the negative electrode lead 26 is welded to the battery can 11, and the wound positive electrode 21 and the negative electrode 22 are formed by a pair of insulating plates 12 and 13. It is stored inside the sandwiched battery can 11. Next, after the positive electrode 21 and the negative electrode 22 are housed inside the battery can 11, the electrolytic solution is injected into the inside of the battery can 11 to impregnate the separator 23. Next, the battery lid 14, the safety valve mechanism 15, and the heat-sensitive resistance element 16 are fixed to the open end of the battery can 11 by caulking via the sealing gasket 17. As a result, the battery shown in FIG. 2 is obtained.

[effect]
In the battery according to the second embodiment, since the positive electrode active material layer 21B contains the positive electrode active material according to the first embodiment, the cycle characteristics can be improved. In particular, when the positive electrode potential (vsLi / Li ⁺ ) in the fully charged state exceeds 4.40 V, the above effect is remarkably exhibited.

Further, when the peak intensity ratio I _A / I _B satisfies the relationship of 1.4 ≤ I _A / I _B <2.5, the cycle characteristics are improved and the metal elution during high temperature storage is suppressed. be able to.

<3 Third embodiment>
[Battery configuration]
As shown in FIG. 4, the battery according to the third embodiment of the present disclosure is a so-called laminated film type battery, and the wound electrode body 30 to which the positive electrode lead 31 and the negative electrode lead 32 are attached has a film-like exterior. It is housed inside the member 40, and can be made smaller, lighter, and thinner.

The positive electrode lead 31 and the negative electrode lead 32 are respectively led out from the inside of the exterior member 40 toward the outside, for example, in the same direction. The positive electrode lead 31 and the negative electrode lead 32 are each made of a metal material such as aluminum, copper, nickel, or stainless steel, and have a thin plate shape or a mesh shape, respectively.

The exterior member 40 is made of, for example, a rectangular aluminum laminated film in which a nylon film, an aluminum foil, and a polyethylene film are bonded in this order. The exterior member 40 is arranged so that, for example, the polyethylene film side and the wound electrode body 30 face each other, and the outer edge portions thereof are brought into close contact with each other by fusion or adhesive. A close contact film 41 for preventing the intrusion of outside air is inserted between the exterior member 40 and the positive electrode lead 31 and the negative electrode lead 32. The adhesion film 41 is made of a material having adhesion to the positive electrode lead 31 and the negative electrode lead 32, for example, a polyolefin resin such as polyethylene, polypropylene, modified polyethylene or modified polypropylene.

The exterior member 40 may be made of a laminate film having another structure, a polymer film such as polypropylene, or a metal film instead of the aluminum laminate film described above. Alternatively, a laminated film in which an aluminum film is used as a core material and a polymer film is laminated on one side or both sides thereof may be used.

FIG. 5 is a cross-sectional view taken along the line VV of the wound electrode body 30 shown in FIG. The winding type electrode body 30 is formed by laminating and winding a positive electrode 33 and a negative electrode 34 via a separator 35 and an electrolyte layer 36, and the outermost peripheral portion thereof is protected by a protective tape 37.

The positive electrode 33 has a structure in which the positive electrode active material layer 33B is provided on one side or both sides of the positive electrode current collector 33A. The negative electrode 34 has a structure in which the negative electrode active material layer 34B is provided on one side or both sides of the negative electrode current collector 34A, and the negative electrode active material layer 34B and the positive electrode active material layer 33B are arranged so as to face each other. There is. The configurations of the positive electrode collector 33A, the positive electrode active material layer 33B, the negative electrode current collector 34A, the negative electrode active material layer 34B, and the separator 35 are the positive electrode current collector 21A, the positive electrode active material layer 21B, and the negative electrode, respectively, in the second embodiment. This is the same as the current collector 22A, the negative electrode active material layer 22B, and the separator 23.

The electrolyte layer 36 contains an electrolytic solution and a polymer compound serving as a retainer for holding the electrolytic solution, and is in the form of a so-called gel. The gel-like electrolyte layer 36 is preferable because it can obtain high ionic conductivity and can prevent liquid leakage from the battery. The electrolytic solution is the electrolytic solution according to the second embodiment. Examples of the polymer compound include polyacrylonitrile, polyvinylidene fluoride, a copolymer of vinylidene fluoride and hexafluoropropylene, polytetrafluoroethylene, polyhexafluoropropylene, polyethylene oxide, polypropylene oxide, polyphosphazene, and polysiloxane. , Polyvinylacetate, polyvinyl alcohol, polymethylmethacrylate, polyacrylic acid, polymethacrylic acid, styrene-butadiene rubber, nitrile-butadiene rubber, polystyrene or polycarbonate. Particularly from the viewpoint of electrochemical stability, polyacrylonitrile, polyvinylidene fluoride, polyhexafluoropropylene or polyethylene oxide are preferable.

The electrolyte layer 36 may contain inorganic particles. This is because the heat resistance can be further improved. As the inorganic particles, the same inorganic particles contained in the surface layer of the separator 23 of the second embodiment can be used. Further, an electrolytic solution may be used instead of the electrolyte layer 36.

[Battery manufacturing method]
Next, an example of a battery manufacturing method according to the third embodiment of the present disclosure will be described.

First, a precursor solution containing a solvent, an electrolyte salt, a polymer compound, and a mixed solvent is applied to each of the positive electrode 33 and the negative electrode 34, and the mixed solvent is volatilized to form the electrolyte layer 36. Next, the positive electrode lead 31 is attached to the end of the positive electrode current collector 33A by welding, and the negative electrode lead 32 is attached to the end of the negative electrode current collector 34A by welding. Next, the positive electrode 33 and the negative electrode 34 on which the electrolyte layer 36 is formed are laminated via the separator 35 to form a laminated body, and then the laminated body is wound in the longitudinal direction thereof, and a protective tape 37 is placed on the outermost peripheral portion thereof. They are adhered to form a wound electrode body 30. Finally, for example, the wound electrode body 30 is sandwiched between the exterior members 40, and the outer edge portions of the exterior members 40 are brought into close contact with each other by heat fusion or the like and sealed. At that time, the adhesion film 41 is inserted between the positive electrode lead 31 and the negative electrode lead 32 and the exterior member 40. This gives the batteries shown in FIGS. 4 and 5.

Further, this battery may be manufactured as follows. First, the positive electrode 33 and the negative electrode 34 are manufactured as described above, and the positive electrode lead 31 and the negative electrode lead 32 are attached to the positive electrode 33 and the negative electrode 34. Next, the positive electrode 33 and the negative electrode 34 are laminated and wound via the separator 35, and the protective tape 37 is adhered to the outermost peripheral portion to form a wound body. Next, the wound body is sandwiched between the exterior members 40, and the outer peripheral edge portion excluding one side is heat-sealed to form a bag shape, which is stored inside the exterior member 40. Next, an electrolyte composition containing a solvent, an electrolyte salt, a monomer as a raw material for a polymer compound, a polymerization initiator, and other materials such as a polymerization inhibitor, if necessary, is prepared, and an exterior member is prepared. Inject into the inside of 40.

Next, after the electrolyte composition is injected into the exterior member 40, the opening of the exterior member 40 is heat-sealed and sealed in a vacuum atmosphere. Next, heat is applied to polymerize the monomers to form a polymer compound, thereby forming a gel-like electrolyte layer 36. As a result, the batteries shown in FIGS. 4 and 5 can be obtained.

<4 Application example 1>
"Battery packs and electronic devices as application examples"
In Application Example 1, a battery pack and an electronic device including a battery according to a second or third embodiment will be described.

[Battery pack and electronic device configuration]
Hereinafter, a configuration example of the battery pack 300 and the electronic device 400 as application examples will be described with reference to FIG. The electronic device 400 includes an electronic circuit 401 of the main body of the electronic device and a battery pack 300. The battery pack 300 is electrically connected to the electronic circuit 401 via the positive electrode terminal 331a and the negative electrode terminal 331b. The electronic device 400 has, for example, a configuration in which the battery pack 300 can be freely attached and detached by the user. The configuration of the electronic device 400 is not limited to this, and has a configuration in which the battery pack 300 is built in the electronic device 400 so that the battery pack 300 cannot be removed from the electronic device 400 by the user. You may.

When charging the battery pack 300, the positive electrode terminal 331a and the negative electrode terminal 331b of the battery pack 300 are connected to the positive electrode terminal and the negative electrode terminal of the charger (not shown), respectively. On the other hand, when the battery pack 300 is discharged (when the electronic device 400 is used), the positive electrode terminal 331a and the negative electrode terminal 331b of the battery pack 300 are connected to the positive electrode terminal and the negative electrode terminal of the electronic circuit 401, respectively.

Examples of the electronic device 400 include a notebook personal computer, a tablet computer, a mobile phone (for example, a smartphone), a personal digital assistant (PDA), a display device (LCD, EL display, electronic paper, etc.), and an image pickup. Devices (eg digital still cameras, digital video cameras, etc.), audio equipment (eg portable audio players), gaming equipment, cordless phone handsets, electronic books, electronic dictionaries, radios, headphones, navigation systems, memory cards, pacemakers, hearing aids, etc. Electric tools, electric shavers, refrigerators, air conditioners, TVs, stereos, water heaters, microwave ovens, dishwashers, washing machines, dryers, lighting equipment, toys, medical equipment, robots, road conditioners, traffic lights, etc. It is not limited to.

(Electronic circuit)
The electronic circuit 401 includes, for example, a CPU, a peripheral logic unit, an interface unit, a storage unit, and the like, and controls the entire electronic device 400.

(Battery pack)
The battery pack 300 includes an assembled battery 301 and a charge / discharge circuit 302. The assembled battery 301 is configured by connecting a plurality of secondary batteries 301a in series and / or in parallel. The plurality of secondary batteries 301a are connected, for example, in n parallel m series (n and m are positive integers). Note that FIG. 6 shows an example in which six secondary batteries 301a are connected in two parallels and three series (2P3S). As the secondary battery 301a, the battery according to the second or third embodiment is used.

Here, a case where the battery pack 300 includes an assembled battery 301 composed of a plurality of secondary batteries 301a will be described, but the battery pack 300 includes one secondary battery 301a instead of the assembled battery 301. It may be adopted.

The charge / discharge circuit 302 is a control unit that controls the charge / discharge of the assembled battery 301. Specifically, at the time of charging, the charging / discharging circuit 302 controls the charging of the assembled battery 301. On the other hand, at the time of discharging (that is, when the electronic device 400 is used), the charge / discharge circuit 302 controls the discharge to the electronic device 400.

<5 Application example 2>
"Power storage system in vehicles as an application example"
An example in which the present disclosure is applied to a power storage system for a vehicle will be described with reference to FIG. 7. FIG. 7 schematically shows an example of the configuration of a hybrid vehicle adopting the series hybrid system to which the present disclosure applies. The series hybrid system is a vehicle that runs on a power drive power converter using the electric power generated by a generator powered by an engine or the electric power temporarily stored in a battery.

The hybrid vehicle 7200 includes an engine 7201, a generator 7202, a power driving force conversion device 7203, a drive wheel 7204a, a drive wheel 7204b, a wheel 7205a, a wheel 7205b, a battery 7208, a vehicle control device 7209, various sensors 7210, and a charging port 7211. Is installed. The above-mentioned power storage device of the present disclosure is applied to the battery 7208.

The hybrid vehicle 7200 travels by using the electric power driving force conversion device 7203 as a power source. An example of the power driving force conversion device 7203 is a motor. The electric power of the battery 7208 operates the electric power driving force conversion device 7203, and the rotational force of the electric power driving force conversion device 7203 is transmitted to the drive wheels 7204a and 7204b. By using direct current-AC (DC-AC) or reverse conversion (AC-DC conversion) at necessary locations, the power driving force conversion device 7203 can be applied to either an AC motor or a DC motor. The various sensors 7210 control the engine speed via the vehicle control device 7209, and control the opening degree (throttle opening degree) of a throttle valve (not shown). The various sensors 7210 include a speed sensor, an acceleration sensor, an engine speed sensor, and the like.

The rotational force of the engine 7201 is transmitted to the generator 7202, and the electric power generated by the generator 7202 by the rotational force can be stored in the battery 7208.

When the hybrid vehicle decelerates due to a braking mechanism (not shown), the resistance force during deceleration is applied to the power driving force conversion device 7203 as a rotational force, and the regenerative power generated by the power driving force conversion device 7203 by this rotational force is applied to the battery 7208. Accumulate.

By connecting the battery 7208 to an external power source of the hybrid vehicle, it is possible to receive electric power from the external power source using the charging port 211 as an input port and store the received electric power.

Although not shown, an information processing device that performs information processing related to vehicle control based on information related to the secondary battery may be provided. As such an information processing device, for example, there is an information processing device that displays the remaining battery level based on information on the remaining battery level.

In the above, a series hybrid vehicle that runs on a motor using the electric power generated by the generator operated by the engine or the electric power temporarily stored in the battery has been described as an example. However, the present disclosure is also valid for a parallel hybrid vehicle in which the outputs of the engine and the motor are used as drive sources, and the three methods of running only with the engine, running only with the motor, and running with the engine and the motor are appropriately switched. Applicable. Further, the present disclosure can be effectively applied to a so-called electric vehicle that travels by being driven only by a drive motor without using an engine.

The example of the hybrid vehicle 7200 to which the technology according to the present disclosure can be applied has been described above. The technique according to the present disclosure can be suitably applied to the battery 7208 among the configurations described above.

<6 Application example 3>
"Power storage system in a house as an application example"
An example in which the present disclosure is applied to a power storage system for a house will be described with reference to FIG. For example, in the power storage system 9100 for a residential 9001, power is stored from a centralized power system 9002 such as thermal power generation 9002a, nuclear power generation 9002b, and hydroelectric power generation 9002c via a power network 9009, an information network 9012, a smart meter 9007, a power hub 9008, and the like. It is supplied to the device 9003. At the same time, electric power is supplied to the power storage device 9003 from an independent power source such as the home power generation device 9004. The electric power supplied to the power storage device 9003 is stored. The electric power used in the house 9001 is supplied by using the power storage device 9003. The same power storage system can be used not only for the house 9001 but also for the building.

The house 9001 is provided with a power generation device 9004, a power consumption device 9005, a power storage device 9003, a control device 9010 for controlling each device, a smart meter 9007, and a sensor 9011 for acquiring various information. Each device is connected by a power grid 9009 and an information network 9012. A solar cell, a fuel cell, or the like is used as the power generation device 9004, and the generated power is supplied to the power consumption device 9005 and / or the power storage device 9003. The power consuming device 9005 includes a refrigerator 9005a, an air conditioner 9005b, a television receiver 9005c, a bath 9005d, and the like. Further, the power consuming device 9005 includes an electric vehicle 9006. The electric vehicle 9006 is an electric vehicle 9006a, a hybrid car 9006b, and an electric motorcycle 9006c.

The battery unit of the present disclosure described above is applied to the power storage device 9003. The power storage device 9003 is composed of a secondary battery or a capacitor. For example, it is composed of a lithium ion battery. The lithium ion battery may be a stationary type or may be used in the electric vehicle 9006. The smart meter 9007 has a function of measuring the usage of commercial power and transmitting the measured usage to the electric power company. The power grid 9009 may be a combination of any one or a plurality of DC power supply, AC power supply, and non-contact power supply.

The various sensors 9011 are, for example, a human sensor, an illuminance sensor, an object detection sensor, a power consumption sensor, a vibration sensor, a contact sensor, a temperature sensor, an infrared sensor, and the like. The information acquired by the various sensors 9011 is transmitted to the control device 9010. With the information from the sensor 9011, the state of the weather, the state of a person, and the like can be grasped, and the power consumption device 9005 can be automatically controlled to minimize the energy consumption. Further, the control device 9010 can transmit information about the house 9001 to an external electric power company or the like via the Internet.

The power hub 9008 performs processing such as branching of power lines and DC / AC conversion. As a communication method of the information network 9012 connected to the control device 9010, a method using a communication interface such as UART (Universal Asynchronous Receiver-Transmitter), Bluetooth (registered trademark), ZigBee (registered trademark). , Wi-Fi, etc. There is a method of using a sensor network based on a wireless communication standard. The Bluetooth® method is applied to multimedia communication and can perform one-to-many connection communication. ZigBee® uses the physical layer of the Institute of Electrical and Electronics Engineers (IEEE) 802.15.4. IEEE802.154 is the name of a short-range wireless network standard called PAN (Personal Area Network) or W (Wireless) PAN.

The control device 9010 is connected to an external server 9013. The server 9013 may be managed by any of the housing 9001, the electric power company, and the service provider. The information sent and received by the server 9013 is, for example, power consumption information, life pattern information, power charges, weather information, natural disaster information, and power transaction information. This information may be transmitted and received from a power consuming device in the home (for example, a television receiver), or may be transmitted and received from a device outside the home (for example, a mobile phone). This information may be displayed on a device having a display function, for example, a television receiver, a mobile phone, a PDA (Personal Digital Assistants), or the like.

The control device 9010 that controls each unit is composed of a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), and the like, and is stored in the power storage device 9003 in this example. The control device 9010 is connected to a power storage device 9003, a home power generation device 9004, a power consumption device 9005, various sensors 9011, and a server 9013 by an information network 9012, and has, for example, a function of adjusting the amount of commercial power used and the amount of power generated. have. In addition, it may be provided with a function of conducting electric power transactions in the electric power market.

As described above, not only the centralized power system 9002 such as thermal power 9002a, nuclear power 9002b, and hydraulic power 9002c, but also the power generated by the domestic power generation device 9004 (solar power generation, wind power generation) can be stored in the power storage device 9003. can. Therefore, even if the generated power of the home power generation device 9004 fluctuates, it is possible to control the amount of power sent to the outside to be constant or to discharge as much as necessary. For example, the electric power obtained by solar power generation is stored in the power storage device 9003, the late-night power with a low charge is stored in the power storage device 9003 at night, and the power stored by the power storage device 9003 is discharged during the time when the charge is high in the daytime. You can also use it.

In this example, although the example in which the control device 9010 is stored in the power storage device 9003 has been described, it may be stored in the smart meter 9007 or may be configured independently. Further, the power storage system 9100 may be used for a plurality of homes in an apartment house, or may be used for a plurality of detached houses.

The example of the power storage system 9100 to which the technique according to the present disclosure can be applied has been described above. The technique according to the present disclosure can be suitably applied to the secondary battery included in the power storage device 9003 among the configurations described above.

Hereinafter, the present disclosure will be specifically described with reference to Examples, but the present disclosure is not limited to these Examples.

[Example 1-1]
(Process for producing powder of core particles (1))
Commercially available lithium carbonate and cobalt oxide are mixed so that the molar ratio (Li: Co) of Li and Co is 1: 1 and fired in air at 1000 ° C. for 6 hours and slowly cooled to average. A powder of core particles (1) having a particle diameter of 20 μm and a specific surface area of 0.3 m ² _{/ g (a powder of LiCoO 2} particles) was obtained.

(Manufacturing step of covering material (1))
By mixing cobalt oxide and lithium carbonate so that the molar ratio (Li: Co) of Li and Co is 0.98: 1, firing in air at 1000 ° C for 6 hours, and quenching at room temperature. , A coating material (1) ( _{a powder of LiCoO 2} particles) was obtained.

(Step of surface modification (1))
First, powder (powder of LiCoO ₂ particles) of the obtained powder of core particles (1) (LiCoO ₂ particles of the powder) 97 wt% and the coating material (1) 3 blended mass% and, a high speed rotary impact milling It was put into a high-speed stirring and mixing machine (Nobilta, manufactured by Hosokawa Micron Co., Ltd.), which is a kind of machine. Next, the rotary blade is rotated at 1500 rpm and treated for 10 minutes, and the coating material (1) is adhered to the surface of the core particles (1) to obtain positive electrode active material particles (coated composite particles). Obtained powder.

[Example 1-2]
The same as in Example 1-1, except that 98% by mass of the core particle powder (1) (LiCoO ₂ particle powder) and 2% by mass of the coating material (1) (LiCoO _{2 particle powder) were blended.} A powder of positive electrode active material particles was obtained.

[Example 1-3]
The same as in Example 1-1, except that 99% by mass of the core particle powder (1) (LiCoO ₂ particle powder) and 1% by mass of the coating material (1) (LiCoO _{2 particle powder) were blended.} A powder of positive electrode active material particles was obtained.

[Comparative Example 1-1]
The same as in Example 1-1 except that the core particle powder (1) (LiCoO ₂ particle powder) 95% by mass and the coating material (1) (LiCoO ₂ particle powder) 5% by mass were blended. A powder of positive electrode active material particles was obtained.

[Comparative Example 1-2]
Example 1-1 except that the powder of the core particles (1) (powder of LiCoO ₂ particles) 99.5% by mass and the coating material (1) ( _{powder of LiCoO 2} particles) 0.5% by mass were blended. In the same manner as above, a powder of positive electrode active material particles was obtained.

[Example 2-1]
(Process for producing powder of core particles (2))
Commercially available lithium carbonate and cobalt oxide are mixed so that the molar ratio (Li: Co) of the amount of Li and the amount of Co is 1.05: 1, and the mixture is fired in air at 1000 ° C. for 6 hours and slowly cooled. _{A powder (LiCoO 2} particle powder) of core particles (2) having an average particle diameter of 20 μm and a specific surface area of 0.3 m ^{2 / g was obtained.}

(Step of surface modification (2))
First, 1000 ml of ultrapure water, 14 g of citric acid and 27 g of disodium hydrogen phosphate were mixed to obtain a solution, and then 100 g of the powder of the core particles (2) was dispersed in the obtained solution. Next, the solution was stirred for 60 minutes and suction filtered. Then, it was heat-treated at 120 ° C. for 12 hours in a vacuum atmosphere to obtain a powder of _{positive electrode active material particles (powder of surface-modified LiCoO 2 particles).}

[Example 2-2]
A powder of positive electrode active material particles was obtained in the same manner as in Example 2-1 except that the stirring time in the step of surface modification (2) was 30 min.

[Example 2-3]
A powder of positive electrode active material particles was obtained in the same manner as in Example 2-1 except that the stirring time in the step of surface modification (2) was 20 min.

[Comparative Example 2-1]
A powder of positive electrode active material particles was obtained in the same manner as in Example 2-1 except that the stirring time in the step of surface modification (2) was 90 min.

[Comparative Example 2-2]
A powder of positive electrode active material particles was obtained in the same manner as in Example 2-1 except that the stirring time in the step of surface modification (2) was 5 min.

[Example 3-1]
(Process for producing powder of core particles (1))
A powder of core particles (1) (powder of LiCoO ₂ particles) was prepared in the same manner as in Example 1-1.

(Step of surface modification (3))
First, 100 parts by weight of the powder of the core particles (1) (powder of ₂ LiCoO particles) is stirred and dispersed in 3000 parts by weight of a 2N lithium hydroxide (LiOH) aqueous solution at 65 ° C. for 1 hour to obtain a first solution. rice field. Then, nickel nitrate commercial reagents _{(Ni (NO 3) 2 ·} 6H 2 O) 3.33 parts by weight of manganese nitrate _{(Mn (NO 3) 2 ·} 6H 2 O) 1.12 parts by weight and 100 parts by weight A second solution dissolved in pure water was prepared, the second solution was added to the first solution over 2 hours, and then stirring and dispersion were continued at 65 ° C. for 1 hour, and the mixture was allowed to cool to form a dispersion system. Obtained. Subsequently, this dispersion system was filtered and dried at 120 ° C. to obtain a precursor. The obtained precursor sample 100 parts by weight of the obtained, in order to adjust the amount of lithium, impregnated with ₍₂ CO ₃ Li) solution 100 parts by weight of lithium carbonate 2N, was uniformly mixed dry, a calcination precursor rice field. Next, the firing precursor was heated at a rate of 5 ° C. per minute using an electric furnace, held at 850 ° C. for 5 hours, and then cooled to room temperature at 30 ° C./min. As a result, a powder of positive electrode active material particles (powder of surface-modified LiCoO ₂ particles) was obtained.

(Example 3-2)
A powder of positive electrode active material particles was obtained in the same manner as in Example 3-1 except that the cooling after coating firing in the step of surface modification (3) was 20 ° C./min.

(Example 3-3)
A powder of positive electrode active material particles was obtained in the same manner as in Example 3-1 except that the cooling after coating firing in the step of surface modification (3) was 10 ° C./min.

(Comparative Example 3-1)
A powder of positive electrode active material particles was obtained in the same manner as in Example 3-1 except that the cooling after coating firing in the step of surface modification (3) was 50 ° C./min.

(Comparative Example 3-2)
A powder of positive electrode active material particles was obtained in the same manner as in Example 3-1 except that the cooling after coating firing in the step of surface modification (3) was performed at 5 ° C./min.

(Comparative Example 4)
The powder of the core particles (1) (powder of LiCoO ₂ particles) was prepared in the same manner as in Example 1-1, and the powder in the as-is state was used as the powder of the positive electrode active material particles.

(evaluation)
The powder of the positive electrode active material particles obtained as described above was evaluated as follows.

(Surface oxygen state of positive electrode active material particles)
The oxygen state on the surface of the positive electrode active material particles obtained as described above was measured as follows.
Using the beamline BL16XU (SPring-8), the spectrum of the O1s orbital on the surface of the positive electrode active material particles was measured by HAXPES using hard X-rays with an incident energy of 7.94 keV.

The energy calibration of the photoelectron spectrum was as follows. The line obtained by linearly approximating the spectrum of the upper part of the valence band was defined as L1, the tangent line at the inflection point of the edge portion was defined as L2, and the intensity of the intersection was defined as I0. The energy at which the intensity becomes I0 / 2 on L2 was defined as the Fermi level EF. In the measurement of this evaluation, it was 7944.054 eV. The difference from this EF was calculated as the binding energy BE.

Although it is difficult to distinguish between the shift due to charging and the Fermi level shift of the material, the carbon tape was shifted so that the CC peak was 285 eV, and the effects of charging were recalibrated and compared.

As a result of the above measurement, the positive electrode active material particles showed peaks in the region A having a binding energy of 528 eV or more and 532 eV or less and the region B having a binding energy of more than 532 eV and 536 eV or less. The maximum intensities of the peaks in the regions A and B were defined as I _A and I _B , and the peak intensity ratio I _A / I _B was determined. The results are shown in Table 1.

(Capacity maintenance rate)
Using the positive electrode active material obtained as described above, a non-aqueous electrolyte secondary battery was produced as follows.

The positive electrode was prepared as follows. First, a positive electrode mixture was prepared by mixing 98% by mass of the positive electrode active material, 0.8% by mass of amorphous carbon powder (Ketchen Black), and 1.2% by mass of polyvinylidene fluoride (PVdF). Next, this positive electrode mixture was dispersed in N-methyl-2-pyrrolidone (NMP) to prepare a positive electrode mixture slurry. Subsequently, this positive electrode mixture slurry was uniformly applied to a positive electrode current collector made of strip-shaped aluminum foil, and the obtained coated material was dried with warm air and then stamped to φ15 mm and compression-molded with a hydraulic press. As a result, a positive electrode was obtained.

The negative electrode was prepared as follows. First, 95% by mass of graphite powder and 5% by mass of PVdF were mixed to prepare a negative electrode mixture. Next, this negative electrode mixture was dispersed in N-methyl-2-pyrrolidone to prepare a negative electrode mixture slurry. Subsequently, the negative electrode mixture slurry was uniformly applied to the negative electrode current collector made of strip-shaped copper foil, dried with warm air, and then compressed to φ16 mm by compression molding. As a result, a negative electrode was obtained.

Using the positive and negative electrodes prepared as described above, a battery was manufactured as follows. First, an electrode body was produced by laminating a positive electrode and a negative electrode via a porous polyolefin film. Next, ethylene carbonate and propylene carbonate were mixed so that the volume mixing ratio was 1: 1 to prepare a mixed solution. _{Subsequently, LiPF 6} was dissolved in this mixed solution to a concentration of ^{1 mol / dm 3} to prepare a non-aqueous electrolyte solution. Finally, a CR2032 coin-type non-aqueous electrolyte secondary battery was produced using the above-mentioned electrode body and electrolytic solution.

The capacity retention rate of the non-aqueous electrolyte secondary battery produced as described above was determined as follows. First, charging is performed under charging conditions of an ambient temperature of 23 ° C., a charging voltage of 4.45 V, a charging current of 0.5 mA, and a charging time of 10 hours, and then discharging is performed under a discharge condition of a discharge current of 2.5 mA and a final voltage of 3.0 V. The initial discharge capacity (discharge capacity in the first cycle) was measured. Next, after repeating charging and discharging under the charging conditions of a charging voltage of 4.35 V, a charging current of 2.5 mA, a charging time of 2 hours, a discharging current of 2.5 mA, and a final voltage of 3.0 V, the 50th cycle is reached. The discharge capacity was measured. Next, using the discharge capacity of the first cycle and the discharge capacity of the 50th cycle, the capacity retention rate after 50 cycles was calculated from the following formula. The results are shown in Table 1.
Capacity retention rate after 50 cycles [%] = (Discharge capacity in the 50th cycle / Discharge capacity in the 1st cycle) x 100

(High temperature storage characteristics)
Except for arranging two porous polyolefin films between the positive electrode and the negative electrode, a non-aqueous electrolyte secondary battery was produced in the same manner as in the evaluation of the “capacity retention rate” described above, and the high temperature of this secondary battery was obtained. The storage characteristics were evaluated as shown below. First, charging was performed under the conditions of an ambient temperature of 23 ° C., a charging voltage of 4.35 V, a charging current of 0.5 mA, and a charging time of 10 hours, and then discharging was performed under the conditions of a discharge current of 0.5 mA and a final voltage of 3.0 V. .. Next, the battery was charged under the conditions of an environment temperature of 23 ° C., a charging voltage of 4.35 V, a charging current of 0.5 mA, and a charging time of 10 hours, and then stored in an environment of a high temperature of 60 ° C. for 168 hours. The cell after storage is disassembled, the negative electrode and the separator are boiled in 15 ml of hydrochloric acid 1M for 15 minutes, the solution is filtered, and the solution is contained in the solution by an SPS3100 sequential ICP emission spectrophotometer (manufactured by Hitachi High-Tech Science). The concentration of Co was measured, and the amount of Co elution during storage was measured by the following formula. The results are shown in Table 1. The measurement results are shown as relative values with the Co elution amount of Example 1 as 100.
Co elution amount = (Co concentration) / (weight of active substance contained in positive electrode)

Table 1 shows the production conditions and evaluation results of the positive electrode active materials of Examples 1-1 to 2-2 and Comparative Examples 1-1 to 4.

The following can be seen from the above evaluation results.
When the peak intensity ratio I _A / I _B is 2.5 or more, the cycle characteristics may deteriorate. On the other hand, if the peak intensity ratio I _A / I _B is less than 1.4, a large amount of Co may be eluted.
In _{the powder of the positive electrode active material particles in which LiCoO 2} particles are coated with a coating layer containing Ni and Mn, the elution of Co can be particularly suppressed.

Although the embodiments of the present disclosure, variations thereof, and examples have been specifically described above, the present disclosure is not limited to the above-described embodiments, variations thereof, and examples, and the present disclosure is not limited to the above-mentioned embodiments. Various modifications based on technical ideas are possible.

For example, the above-described embodiments and modifications thereof, as well as the configurations, methods, processes, shapes, materials, numerical values, and the like given in the embodiments are merely examples, and different configurations, methods, processes, and shapes may be used as necessary. , Materials and numerical values may be used. Further, the chemical formula of a compound or the like is typical, and if it is a general name of the same compound, it is not limited to the stated valence and the like.

In addition, the above-described embodiments and modifications thereof, as well as the configurations, methods, processes, shapes, materials, numerical values, and the like of the embodiments can be combined with each other as long as they do not deviate from the gist of the present disclosure.

Further, in the above-described embodiments and examples, examples of applying the present disclosure to cylindrical and laminated film type secondary batteries have been described, but the shape of the battery is not particularly limited. For example, the present disclosure can be applied to secondary batteries such as square type and coin type, and can be applied to flexible batteries mounted on smart watches, head-mounted displays, wearable terminals such as iGlass (registered trademark), and the like. It is also possible to apply the disclosure.

Further, in the above-described embodiments and examples, an example in which the present disclosure is applied to a wound type secondary battery has been described, but the structure of the battery is not limited to this, and for example, a positive electrode and a negative electrode are described. The present disclosure is also applicable to a laminated battery (stack type battery) in which the batteries are laminated via a separator, or a battery in which a positive electrode and a negative electrode are folded with a separator sandwiched between them.

Further, in the above-described embodiments and examples, an example in which the present disclosure is applied to a lithium ion secondary battery and a lithium ion polymer secondary battery has been described, but the types of batteries to which the present disclosure can be applied are limited to this. Not a thing. For example, the present disclosure may be applied to an all-solid-state battery such as an all-solid-state lithium-ion secondary battery.

Further, in the above-described embodiments and examples, the configuration in which the electrode includes the current collector and the active material layer has been described as an example, but the configuration of the electrode is not limited to this. For example, the electrode may be configured to consist only of an active material layer.

The present disclosure may also adopt the following configuration.
(1)
A positive electrode containing powder of positive electrode active material particles, a negative electrode, and an electrolyte are provided.
The positive electrode active material particles contain at least one of lithium cobalt oxide and a part of lithium cobalt oxide substituted with other metal elements, and hard X-rays using 7.94 keV hard X-rays. When the spectrum of the O1s orbital on the surface of the positive electrode active material particles was measured by photoelectron spectroscopy, peaks were shown in the region A with a coupling energy of 528 eV or more and 532 eV or less and the region B of more than 532 eV and 536 eV or less.
A battery in which the peak intensity ratio I _A / I _B satisfies the relationship of I _A / I _B <2.5 when the maximum intensities of the peaks in the regions A and B are I _A and I _{B, respectively.}
(2)
The battery according to (1), wherein the powder of the positive electrode active material particles has an average composition represented by the following formula (1).
_{Li x Co 1-y M y} O 2-z ··· (1)
(M is of magnesium, aluminum, boron, titanium, vanadium, chromium, iron, copper, zinc, molybdenum, tin, tungsten, zirconium, yttrium, niobium, calcium, strontium, bismuth, sodium, potassium, silicon and phosphorus. At least one kind. X, y and z satisfy 0 ≦ x ≦ 1, 0 ≦ y <0.5 and −0.1 ≦ z ≦ 0.2).
(3)
The positive electrode active material particles are
The particles containing lithium cobalt oxide and
A coating layer covering at least a part of the surface of the particles is provided.
The coating layer is made of lithium, nickel, manganese, magnesium, aluminum, boron, titanium, vanadium, chromium, iron, cobalt, copper, zinc, molybdenum, tin, tungsten, zirconium, ittrium, niobium, calcium and strontium. The battery according to (1) or (2), which comprises an oxide containing at least one element in the group.
(4)
The positive electrode active material particles are
The particles containing lithium cobalt oxide and
A coating layer covering at least a part of the surface of the particles is provided.
The battery according to any one of (1) to (3), wherein the coating layer contains an oxide containing lithium, nickel, and manganese.
(5)
The battery according to any one of (1) to (4), wherein the peak intensity ratio I _A / I _B satisfies the relationship of 1.4 ≤ I _A / I _{B <2.5.}
(6)
The battery according to any one of (1) to (5), wherein the peak intensity ratio I _A / I _B satisfies the relationship of 1.4 ≤ I _A / I _{B ≤ 2.}
(7)
The battery according to any one of (1) to (6), wherein the surface of the positive electrode active material particles is in a state of lacking oxygen as compared with the inside of the positive electrode active material particles.
(8)
Contains powder of positive electrode active material particles,
The positive electrode active material particles contain at least one of lithium cobalt oxide and a part of lithium cobalt oxide substituted with other metal elements, and hard X-rays using 7.94 keV hard X-rays. When the spectrum of the O1s orbital on the surface of the positive electrode active material particles was measured by photoelectron spectroscopy, peaks were shown in the region A with a coupling energy of 528 eV or more and 532 eV or less and the region B of more than 532 eV and 536 eV or less.
When the maximum intensities of the peaks in the regions A and B are I _A and I _B , the peak intensity ratio I _A / I _B satisfies the relationship of I _A / I _{B <2.5.} ..
(9)
Contains powder of positive electrode active material particles,
The positive electrode active material particles contain at least one of lithium cobalt oxide and a part of lithium cobalt oxide substituted with other metal elements, and hard X-rays using 7.94 keV hard X-rays. When the spectrum of the O1s orbital on the surface of the positive electrode active material particles was measured by photoelectron spectroscopy, peaks were shown in the region A with a coupling energy of 528 eV or more and 532 eV or less and the region B of more than 532 eV and 536 eV or less.
A positive electrode in which the peak intensity ratio I _A / I _B satisfies the relationship of I _A / I _B <2.5 when the maximum intensities of the peaks in the regions A and B are I _A and I _{B, respectively.}
(10)
The battery according to any one of (1) to (7) and
A control unit that controls the battery and
Battery pack with.
(11)
Equipped with the battery according to any one of (1) to (7),
An electronic device that receives power from the battery.
(12)
The battery according to any one of (1) to (7) and
A conversion device that receives electric power from the battery and converts it into vehicle driving force.
An electric vehicle including a control device that processes information related to vehicle control based on the information on the battery.
(13)
Equipped with the battery according to any one of (1) to (7),
A power storage device that supplies electric power to an electronic device connected to the battery.
(14)
Equipped with the battery according to any one of (1) to (7),
A power system that receives power from the battery.

11 Battery can 12, 13 Insulation plate 14 Battery lid 15 Safety valve mechanism 15A Disc plate 16 Heat-sensitive resistance element 17 Gasket 20 Winding type electrode body 21 Positive electrode 21A Positive electrode collector 21B Positive electrode active material layer 22 Negative electrode 22A Negative electrode current collector 22B Negative electrode active material layer 23 Separator 24 Center pin 25 Positive electrode lead 26 Negative electrode lead

Claims (12)

A positive electrode containing powder of positive electrode active material particles, a negative electrode, and an electrolyte are provided.
The positive electrode active material particles contain at least one of lithium cobaltate and a part of cobalt of lithium cobaltate substituted with other metal elements, and the surface of the positive electrode active material particles is the positive electrode active material. Oxygen is deficient compared to the inside of the particles, and the bond energy is measured when the spectrum of the O1s orbital on the surface of the positive electrode active material particles is measured by hard X-ray photoelectron spectroscopy using 7.94 keV hard X-rays. Peaks were shown in the region A of 528 eV or more and 532 eV or less and the region B of more than 532 eV and 536 eV or less.
The region A, the region B a maximum intensity of the peak in each _I A, when the _{I B,} the peak intensity ratio _I A / _{I B is, 1.4 ≦ I A / I B} <2.5 in the relationship Batteries to fill. The battery according to claim 1, wherein the powder of the positive electrode active material particles has an average composition represented by the following formula (1).
_{Li x Co 1-y M y} O 2-z ··· (1)
(M is of magnesium, aluminum, boron, titanium, vanadium, chromium, iron, copper, zinc, molybdenum, tin, tungsten, zirconium, yttrium, niobium, calcium, strontium, bismuth, sodium, potassium, silicon and phosphorus. At least one kind. X, y and z satisfy 0 ≦ x ≦ 1, 0 ≦ y <0.5 and −0.1 ≦ z ≦ 0.2). The positive electrode active material particles are
The particles containing lithium cobalt oxide and
A coating layer covering at least a part of the surface of the particles is provided.
The coating layer is made of lithium, nickel, manganese, magnesium, aluminum, boron, titanium, vanadium, chromium, iron, cobalt, copper, zinc, molybdenum, tin, tungsten, zirconium, ittrium, niobium, calcium and strontium. The battery according to claim 1, which comprises an oxide containing at least one element in the group. The positive electrode active material particles are
The particles containing lithium cobalt oxide and
A coating layer covering at least a part of the surface of the particles is provided.
The battery according to claim 1, wherein the coating layer contains an oxide containing lithium, nickel, and manganese. The peak intensity ratio _I A / _{I B} is, 1.4 ≦ _I A / _I cell according to any one of claims 1 4 satisfying _B ≦ 2 relationship. Contains powder of positive electrode active material particles,
The positive electrode active material particles contain at least one of lithium cobaltate and a part of cobalt of lithium cobaltate substituted with other metal elements, and the surface of the positive electrode active material particles is the positive electrode active material. Oxygen is deficient compared to the inside of the particles, and the bond energy is measured when the spectrum of the O1s orbital on the surface of the positive electrode active material particles is measured by hard X-ray photoelectron spectroscopy using 7.94 keV hard X-rays. Peaks were shown in the region A of 528 eV or more and 532 eV or less and the region B of more than 532 eV and 536 eV or less.
The region A, the region B a maximum intensity of the peak in each _I A, when the _{I B,} the peak intensity ratio _I A / _{I B is, 1.4 ≦ I A / I B} <2.5 in the relationship Positive electrode active material to meet. Contains powder of positive electrode active material particles,
The positive electrode active material particles contain at least one of lithium cobaltate and a part of cobalt of lithium cobaltate substituted with other metal elements, and the surface of the positive electrode active material particles is the positive electrode active material. Oxygen is deficient compared to the inside of the particles, and the bond energy is measured when the spectrum of the O1s orbital on the surface of the positive electrode active material particles is measured by hard X-ray photoelectron spectroscopy using 7.94 keV hard X-rays. Peaks were shown in the region A of 528 eV or more and 532 eV or less and the region B of more than 532 eV and 536 eV or less.
The region A, the region B a maximum intensity of the peak in each _I A, when the _{I B,} the peak intensity ratio _I A / _{I B is, 1.4 ≦ I A / I B} <2.5 in the relationship Positive electrode to meet. The battery according to any one of claims 1 to 5.
A control unit that controls the battery and
Battery pack with. The battery according to any one of claims 1 to 5 is provided.
An electronic device that receives power from the battery. The battery according to any one of claims 1 to 5.
A conversion device that receives electric power from the battery and converts it into vehicle driving force.
An electric vehicle including a control device that processes information related to vehicle control based on the information on the battery. The battery according to any one of claims 1 to 5 is provided.
A power storage device that supplies electric power to an electronic device connected to the battery. The battery according to any one of claims 1 to 5 is provided.
A power system that receives power from the battery.

Images