JP2013222502A - Positive electrode active material, method of manufacturing the same, positive electrode, battery, battery pack, electronic apparatus, electric vehicle, power storage device and electric power system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a positive electrode active material capable of improving cycle characteristics.SOLUTION: A positive electrode active material contains secondary particles made by aggregation of primary particles. The primary particle contains lithium (Li) and manganese (Mn) and is a particle of a transition metal complex oxide having a spinel type structure. The primary particle is a polyhedron having a structural face exceeding eight faces, a ratio (B/A) is 2 or more and 20 or less, where A represents an average number of primary particles which are contained in the secondary particles and whose maximum length is 1 μm or more when one secondary particle is observed from one direction and B represents an average number of polyhedron structural faces contained on the surface of the secondary particle when one secondary particle is observed from one direction, and a specific surface area is 0.4 m/g or less.

Description

  The present technology relates to a positive electrode active material and a manufacturing method thereof, a positive electrode, a battery, a battery pack, an electronic device, an electric vehicle, a power storage device, and a power system. Specifically, the present invention relates to a positive electrode active material including secondary particles in which primary particles are aggregated.

In recent years, with the increase in functionality and performance of portable devices such as notebook computers and mobile phones, the power consumption of the devices has increased. For this reason, a much higher capacity is required for the battery serving as the power source. In addition, from the viewpoints of economy and reduction in size and weight of equipment, a secondary battery having a high energy density has been strongly demanded. Furthermore, there is an increasing demand for an electric vehicle or a hybrid electric vehicle that is actively spread to the general public as a low-pollution vehicle against the background of environmental problems. In response to such demands, non-aqueous secondary batteries, particularly lithium ion secondary batteries, have advantages such as high output and high energy density, and thus are attracting much attention. As a positive electrode active material for a lithium ion secondary battery, LiMn ₂ O ₄ having a spinel structure or a part of the Mn substituted with another element is being developed as an inexpensive material having high energy density and high voltage. It has been.

  Patent Document 1 describes a technique for obtaining a flat discharge voltage that facilitates device formation by using a lithium nickel manganate active material in which primary particles have a shape other than octahedron.

  In Patent Document 2, by using a lithium manganate active material having a polyhedral shape of twelve or more planes in which the shape of primary particles is not adjacent to the crystal plane equivalent to the (111) plane, Mn at high temperature is used. A technique for achieving both elution suppression and load characteristics is described.

JP 2008-293997 A

JP 2010-192428 A

In recent years, there has been a demand for a technique capable of improving cycle characteristics in a positive electrode active material in which LiMn ₂ O ₄ having a spinel structure or a part of Mn thereof is substituted with another element.

  Accordingly, an object of the present technology is to provide a positive electrode active material capable of improving cycle characteristics, a manufacturing method thereof, a positive electrode, a battery, a battery pack, an electronic device, an electric vehicle, a power storage device, and a power system.

In order to solve the above-mentioned problem, the first technique is:
Including secondary particles in which primary particles are aggregated,
The primary particles are composite oxide particles having a spinel structure, including lithium (Li) and manganese (Mn),
A primary particle is a polyhedron having more than eight constituent surfaces,
Ratio (B / A) (where A: when one secondary particle is observed from one direction, the average number of primary particles having a maximum length of 1 μm or more contained in the secondary particle, B: from one direction When observing one secondary particle, the average number of polyhedron constituting surfaces contained in the surface of the secondary particle) is 2 or more and 20 or less,
A specific surface area is a positive electrode active material which is 0.4 m < ² > / g or less.

The second technology is
Containing a positive electrode active material including secondary particles in which primary particles are aggregated;
The primary particles are composite oxide particles having a spinel structure, including lithium (Li) and manganese (Mn),
Primary particles are polyhedrons with more than eight faces,
Ratio (B / A) (where A: when one secondary particle is observed from one direction, the average number of primary particles having a maximum length of 1 μm or more contained in the secondary particle, B: from one direction When observing one secondary particle, the average number of polyhedron constituting surfaces contained in the surface of the secondary particle) is 2 or more and 20 or less,
A specific surface area is a positive electrode which is 0.4 m < ² > / g or less.

The third technology is
A positive electrode, a negative electrode, and an electrolyte;
The positive electrode contains a positive electrode active material including secondary particles in which primary particles are aggregated,
The primary particles are composite oxide particles having a spinel structure, including lithium (Li) and manganese (Mn),
Primary particles are polyhedrons with more than eight faces,
Ratio (B / A) (where A: when one secondary particle is observed from one direction, the average number of primary particles having a maximum length of 1 μm or more contained in the secondary particle, B: from one direction When observing one secondary particle, the average number of polyhedron constituting surfaces contained in the surface of the secondary particle) is 2 or more and 20 or less,
The battery has a specific surface area of 0.4 m ² / g or less.

The fourth technology is
A precursor is prepared by layering a carbonate containing manganese (Mn),
This is a method for producing a positive electrode active material, comprising producing particles of a composite oxide having a spinel structure containing lithium and manganese by reacting a precursor with a lithium source.

  The battery pack, the electronic device, the electric vehicle, the power storage device, and the power system according to the present technology include the positive electrode active material of the first technology, the positive electrode of the second technology, or the battery of the third technology.

In the present technology, the primary particles are polyhedrons having crystal faces exceeding eight faces, the ratio (B / A) is in the range of 2 to 20, and the specific surface area is 0.4 m ² / g or less. . Thereby, the exposure amount of the {111} plane where manganese (Mn) and other substitution elements are easily eluted can be reduced, and decomposition of the electrolytic solution by the positive electrode active material can be suppressed.

  As described above, according to the present technology, cycle characteristics can be improved.

FIG. 1 is a cross-sectional view illustrating a configuration example of a nonaqueous electrolyte secondary battery according to a second embodiment of the present technology. FIG. 2 is an enlarged cross-sectional view illustrating a part of the spirally wound electrode body illustrated in FIG. FIG. 3 is an exploded perspective view showing a configuration example of the nonaqueous electrolyte secondary battery according to the third embodiment of the present technology. FIG. 4 is a cross-sectional view taken along line IV-IV of the spirally wound electrode body illustrated in FIG. FIG. 5 is a block diagram illustrating a configuration example of the battery pack according to the fourth embodiment of the present technology. FIG. 6 is a schematic diagram illustrating an example in which the nonaqueous electrolyte secondary battery of the present technology is applied to a residential power storage system. FIG. 7 is a schematic diagram illustrating one configuration of a hybrid vehicle that employs a series hybrid system to which the present technology is applied. FIG. 8 is a characteristic diagram showing XRD patterns of the precursor particles of Example 1 and Comparative Example 3. FIG. 9 is a graph showing the evaluation results of the nonaqueous electrolyte secondary batteries of Examples 1 to 3 and Comparative Examples 1 to 4. FIG. 10A is a view showing an SEM image of the coprecipitated particles of Example 1. FIG. 10B is a diagram showing an SEM image of the positive electrode active material particles of Example 1. FIG. FIG. 10C is a diagram showing an SEM image of the coprecipitated particles of Example 2. 10D is a diagram showing an SEM image of the positive electrode active material particles of Example 2. FIG. FIG. 10E is a view showing an SEM image of the coprecipitated particles of Example 3. 10F is a view showing an SEM image of the positive electrode active material particles of Example 3. FIG. FIG. 11A is a diagram showing an SEM image of the coprecipitated particles of Example 4. FIG. 11B is a diagram showing an SEM image of the positive electrode active material particles of Example 4. FIG. 11C is a diagram showing an SEM image of the coprecipitated particles of Comparative Example 1. FIG. 11D is a diagram showing an SEM image of the positive electrode active material particles of Comparative Example 1. FIG. 11E is a diagram showing an SEM image of coprecipitated particles of Comparative Example 2. FIG. 11F is a diagram showing an SEM image of the positive electrode active material particles of Comparative Example 2. FIG. 12A is a diagram showing an SEM image of coprecipitated particles of Comparative Example 3. 12B is a view showing an SEM image of the positive electrode active material particles of Comparative Example 3. FIG. FIG. 12C is a diagram showing an SEM image of coprecipitated particles of Comparative Example 4. 12D is a diagram showing an SEM image of the positive electrode active material particles of Comparative Example 4. FIG. FIG. 12E is a view showing an SEM image of the coprecipitated particles of Comparative Example 5. 12F is a diagram showing an SEM image of the positive electrode active material particles of Comparative Example 5. FIG. FIG. 13 is a view showing an SEM image for explaining the maximum length Rm of the primary particles.

Embodiments of the present technology will be described in the following order with reference to the drawings.
1. First Embodiment (Example of positive electrode active material)
2. Second Embodiment (Example of Cylindrical Battery)
3. Third Embodiment (Example of flat battery)
4). Fourth embodiment (example of battery pack)
5. Fifth embodiment (example of power storage system)

<1. First Embodiment>
[Composition of cathode active material]
The positive electrode active material includes secondary particles in which primary particles are aggregated, and the primary particles include lithium (Li), manganese (Mn), and oxygen (O), and are composite oxide particles having a spinel structure. If necessary, a part of manganese (Mn) contained in this composite oxide may be substituted with another transition metal element. What substituted a part of manganese (Mn) with the other transition metal element is suitable as a 5V class battery material.

  Examples of other transition metal elements include chromium (Cr), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), titanium (Ti), aluminum (Al), At least one selected from the group consisting of germanium (Ge), gallium (Ga), magnesium (Mg), vanadium (V), and lithium (Li) can be used.

The composite oxide having the above spinel structure preferably has an average composition represented by the following formula (1).
Li _{1 + W} (Mn _2-XY A _X B _Y ) O _4-Z (1)
(In the formula, A (hereinafter referred to as “first transition metal A” as appropriate) is chromium (Cr), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn)). ) And titanium (Ti) and B (hereinafter referred to as “second transition metal B” as appropriate) represents aluminum (Al), germanium (Ge), gallium (Ga). Represents at least one member selected from the group consisting of magnesium (Mg), vanadium (V), and lithium (Li), and W, X, Y, and Z are −0.1 ≦ W ≦ 0.1 and 0 ≦ X. ≦ 0.6, 0 ≦ Y ≦ 0.3, −0.1 ≦ Z ≦ 0.1 The composition of lithium varies depending on the state of charge and discharge, and the value of W is a complete discharge. Represents the value in the state.)
However, when the composite oxide having the above spinel structure includes the first transition metal A as an essential component, X is a value within the range of 0 <X ≦ 0.6. In addition, when the composite oxide having the above spinel structure includes the second transition metal B as an essential component, Y is a value within the range of 0 <Y ≦ 0.3.

  The particle shape of the primary particles is a polyhedron having a flat crystal face exceeding 8 faces, preferably a polyhedron having a flat crystal face exceeding 8 faces and 50 faces or less. By making the shape of the primary particles into a polyhedron having crystal faces exceeding eight faces, the exposure amount of {111} face where manganese (Mn) and other substitution elements are easily eluted can be reduced. The characteristics can be improved. Moreover, since the acute angle part of the primary particle of a positive electrode active material can be reduced and the active point of a positive electrode active material can be reduced, cycling characteristics can be improved. Furthermore, since multiple types of crystal planes can be exposed as the crystal plane of the primary particles of the positive electrode active material, the primary particles of the positive electrode active material have multiple functions such as Mn elution suppression surfaces, Li diffusion promotion surfaces, and activity suppression surfaces. Can be granted.

  Examples of the polyhedron exceeding the octahedron include a 10-hedron, a 14-hedron, a 22-hedron, and a 48-hedron. Here, the polyhedron includes polyhedrons other than regular polyhedrons. In this specification, the entire crystallographically equivalent plane is represented by braces “{}”, for example, {111}, {100}, {110}.

  It is preferable that the crystal planes of the primary particles exceeding eight planes include at least one of {100} planes and {110} planes, and all of the primary crystal planes are {100} planes and {110} planes. } It is more preferable that it is one of the surfaces. From the viewpoint of suppressing the elution of manganese (Mn) and improving the cycle characteristics, it is preferable that the crystal plane constituting the polyhedron includes a {100} plane. From the viewpoint of promoting the diffusion of lithium (Li) and improving the load characteristics, it is preferable that the crystal plane constituting the polyhedron includes a {110} plane. From the viewpoint of imparting multifunctionality (functions such as improvement of cycle characteristics and load characteristics) to the primary particles of the positive electrode active material, the crystal planes constituting the polyhedron include both {100} planes and {110} planes. Preferably it is.

The specific surface area of the secondary particles, 0.40 m ² / g or less, preferably 0.05 m ² / g or more 0.40 m ² / g or less, more preferably 0.05 m ² / g or more 0.25 m ² / g or less , more preferably in the range of 0.10 m ² / g or more 0.20 m ² / g or less. When the specific surface area is 0.05 m ² / g or more, a decrease in load characteristics can be suppressed. On the other hand, when the specific surface area is 0.40 m ² / g or less, the reaction between the positive electrode active material and the electrolytic solution can be suppressed, and the cycle characteristics can be improved.

  The median diameter of the secondary particles is preferably in the range of 10 μm to 50 μm, more preferably 15 μm to 40 μm, and still more preferably 15 μm to 30 μm. When the median diameter is 10 μm or more, the reaction between the positive electrode active material and the electrolytic solution can be suppressed, and the cycle characteristics can be improved. On the other hand, when the median diameter is 50 μm or less, a decrease in load characteristics can be suppressed.

  The average number A of primary particles is preferably in the range of 1 to 50, more preferably 3 to 40, and still more preferably 5 to 30. Here, the average number A of primary particles refers to the average number of primary particles having a maximum length of 1 μm or more contained in the secondary particles when one secondary particle is observed from any one direction. Show. However, the maximum length means the maximum passing length of primary particles in an observable range when one secondary particle is observed from any one direction as described above. When the average number A is 50 or less, the reaction between the positive electrode active material and the electrolytic solution can be suppressed, and cycle characteristics can be improved.

  The average number B of crystal faces of the primary particles is preferably in the range of 10 to 200, more preferably 10 to 50, and still more preferably 20 to 50. Here, the average number B of crystal faces of the primary particles indicates the average number of crystal faces included in the surface of the secondary particles when one secondary particle is observed from any one direction. . When the average number of faces B is 10 or more, the exposure amount of {111} faces where manganese (Mn) and other substitutional elements are easily eluted can be reduced, so that the cycle characteristics can be improved. Moreover, since the acute angle part of the primary particle of a positive electrode active material can be reduced and the active point of a positive electrode active material can be reduced, cycling characteristics can be improved. Furthermore, since multiple types of crystal planes can be exposed as the crystal plane of the primary particles of the positive electrode active material, the primary particles of the positive electrode active material have multiple functions such as Mn elution suppression surfaces, Li diffusion promotion surfaces, and activity suppression surfaces. Can be granted. On the other hand, when the average number of faces B is 200 or less, it is possible to sufficiently secure the exposed area of the {110} face with good Li diffusibility and the {100} face where Mn elution can be expected.

  Ratio (B / A) (A: when one secondary particle is observed from any one direction, the average number of primary particles having a maximum length of 1 μm or more contained in the secondary particle, B: arbitrary The average number of crystal faces included in the surface of the secondary particle when one secondary particle is observed from one direction, where the maximum length is any one direction as described above. Means the maximum length of primary particles in the observable range when one secondary particle is observed from 2 to 20, preferably 2 to 10, more preferably 2 It is within the range of 4 or less. When the ratio (B / A) is 2 or more, it is possible to increase the crystal face of the primary particles that are polyhedrons and to suppress an increase in the specific surface area. Therefore, the exposure amount of the {111} plane where manganese (Mn) and other substitution elements are easily eluted can be reduced, and the reaction between the positive electrode active material and the electrolytic solution can be suppressed. That is, the cycle characteristics can be improved. On the other hand, when the ratio (B / A) is 20 or less, it is possible to sufficiently secure the exposed area of the {110} plane having good Li diffusibility and the {100} plane from which Mn elution can be expected.

A surface layer may be further provided on at least a part of the primary particles or secondary particles of the positive electrode active material. The surface layer functions as a reaction suppression layer for suppressing an oxidation reaction and the like. For example, lithium phosphate (Li ₃ PO ₄ ), lithium niobate (LiNbO ₃ ), lithium titanate (LTO), fluorine It contains at least one selected from the group consisting of aluminum fluoride (AlF ₃ ), aluminum phosphate (AlPO ₄ ), aluminum oxide (Al ₂ O ₃ ), zirconium oxide (ZrO ₂ ), and the like.

[Method for producing positive electrode active material]
Next, the manufacturing method of the positive electrode active material which has the above-mentioned structure is demonstrated.

(Precursor production process)
First, for example, ammonia water is put into a reaction vessel and stirred while being kept at a predetermined temperature (for example, 50 ° C.). Next, the following three types of chemicals (hereinafter referred to as “coprecipitation additive solution”) are added to the ammonia water in the reaction vessel to produce coprecipitate particles containing carbonate. At this time, the pH value in the reaction vessel is preferably set within a range of 6 or more and 10 or less. When the pH value is 6 or more, each metal ion is precipitated simultaneously, and co-precipitated particles having a uniform composition can be efficiently obtained. When the pH value is 10 or less, since the secondary particle size is large, coprecipitated particles having a small specific surface area can be obtained.

Below, three types of coprecipitation addition liquid (1)-(3) used at this process are shown.
(1) A solution containing a transition metal salt (manganese source) containing manganese (Mn) and a transition metal salt (transition metal source other than manganese) containing a transition metal element other than manganese (Mn) as necessary.
(2) Aqueous ammonia (3) Solution containing carbonate (ie carbonate ion)

  Examples of transition metal salts containing manganese (Mn) include transition metal sulfates, transition metal nitrates, transition metal acetates, transition metal chlorides, etc., and these transition metal salts can be used alone or in combination. Also good. As the transition metal salt, for example, at least one selected from the group consisting of manganese sulfate, manganese nitrate, manganese acetate, and manganese chloride can be used.

  Examples of transition metal salts containing transition metal elements other than manganese (Mn) include transition metal sulfates, transition metal nitrates, transition metal acetates, transition metal chlorides, and the like. Two or more kinds may be used in combination. The transition metal other than manganese (Mn) is the same as the transition metal other than manganese (Mn) contained in the positive electrode active material described above. For example, at least one of the first transition metal element A and the second transition metal element B One element. Examples of the transition metal sulfate include a group consisting of chromium sulfate, iron sulfate, cobalt sulfate, nickel sulfate, copper sulfate, zinc sulfate, titanium sulfate, aluminum sulfate, germanium sulfate, gallium sulfate, magnesium sulfate, vanadium sulfate, and lithium sulfate. At least one of them can be used. Examples of the transition metal nitrate include chromium nitrate, iron nitrate, cobalt nitrate, nickel nitrate, copper nitrate, zinc nitrate, titanium nitrate, aluminum nitrate, germanium nitrate, gallium nitrate, magnesium nitrate, vanadium nitrate, and lithium nitrate. At least one of them can be used. Examples of the transition metal acetate include a group consisting of chromium acetate, iron acetate, cobalt acetate, nickel acetate, copper acetate, zinc acetate, titanium acetate, aluminum acetate, germanium acetate, gallium acetate, magnesium acetate, vanadium acetate and lithium acetate. At least one of them can be used.

  It is preferable to prepare the atomic ratio of manganese: first transition metal element A: second transition metal element B in the solution to be, for example, 2-XY: X: Y. However, X and Y are in the range of 0 ≦ X ≦ 0.6 and 0 ≦ Y ≦ 0.3.

  Examples of the carbonate include sodium carbonate and potassium carbonate. These carbonates may be used alone or in combination of two or more.

  The coprecipitated particles produced as described above contain carbonate as a main component. As the carbonate, for example, a transition metal carbonate containing manganese (Mn) and, if necessary, a transition metal element other than manganese (Mn) can be used. The transition metal other than manganese (Mn) is the same as the transition metal other than manganese (Mn) contained in the positive electrode active material described above. For example, at least one of the first transition metal element A and the second transition metal element B One element.

  Next, the coprecipitation reaction liquid containing the coprecipitation particles is recovered from, for example, overflow. Next, the coprecipitated particles containing carbonate as a main component are formed into a layered compound. Specifically, after the recovered liquid is washed with water, the coprecipitated particles are immersed in a hydroxide solution, and then stirred, washed again with water, filtered, and dried. Thereby, precursor particles (precursor powder) as a layered compound are obtained. Examples of hydroxides that can be used include sodium hydroxide and potassium hydroxide. The precursor particles contain a hydroxide containing manganese (Mn) and, if necessary, a transition metal element other than manganese (Mn) as a main component. The average primary particle length of the precursor is preferably 0.01 μm or more and 0.2 μm or less. When the average primary particle length of the precursor is 0.01 μm or more, precursor particles having large secondary particles can be easily obtained, so that the specific surface area when the active material is used can be reduced. On the other hand, when the average primary particle length of the precursor is 0.2 μm or less, the specific surface area is high, so that the reactivity with the lithium compound is high and sintering can be promoted. The shape of the precursor particles is preferably spherical. When it is spherical, precursor particles having a high density can be easily obtained, and the active material particles produced using the precursor particles can be densified.

(Active material production process)
Next, the precursor particles and the lithium compound (lithium source) are weighed so as to have a predetermined molar ratio and mixed by a ball mill or the like. As the lithium compound, for example, lithium carbonate (Li ₂ CO ₃ ) can be used. Next, the mixture is fired in the air and cooled. Here, the firing temperature is preferably in the range of 800 ° C. to 1300 ° C., for example, 1000 ° C. When the firing temperature is 800 ° C. or higher, sintering proceeds, so that a desired crystal plane can be obtained and the specific surface area can be reduced. On the other hand, when the firing temperature is 1300 ° C. or lower, excessive sintering is prevented and a desired crystal plane is easily obtained. The firing time is preferably in the range of 2 hours to 20 hours, for example, 8 hours. If the firing time is less than 2 hours, the sintering is insufficient. On the other hand, if the firing time exceeds 20 hours, it is not preferable in terms of productivity.

Then, after remixing, baking is performed again in the atmosphere. Here, the firing temperature is preferably in the range of 600 ° C. or higher and 900 ° C. or lower, for example 700 ° C. When the firing temperature is 600 ° C. or higher and 900 ° C. or lower, an active material having a spinel structure in which oxygen defects are filled is obtained. The firing time is preferably in the range of 2 hours to 20 hours, for example, 8 hours. When the firing time is less than 2 hours, oxygen defects increase and a spinel structure is not formed. On the other hand, if the firing time exceeds 20 hours, it is not preferable in terms of productivity.
As a result, the intended positive electrode active material is obtained.

[effect]
According to the first embodiment, since the particle shape of the primary particles of the positive electrode active material is a polyhedron having a crystal face exceeding eight faces, {111} face where manganese (Mn) and other substitution elements are easily eluted. The amount of exposure can be reduced. Therefore, cycle characteristics can be improved. In addition, when the particle shape of the primary particles is an octahedron, many {111} faces from which manganese (Mn) and other substitution elements are easily eluted are exposed, so that the cycle characteristics are deteriorated.

Since the primary particle has a polyhedral shape exceeding octahedron and the aggregation of primary particles is reduced, the specific surface area of the positive electrode active material can be remarkably reduced (for example, it can be reduced to 0.1 m ² / g). Thus, by reducing the specific surface area of the positive electrode active material, it is possible to suppress decomposition of the electrolyte and improve cycle characteristics.

  Since the primary particle has a polyhedron shape with more than eight faces, the acute angle portion of the primary particle can be reduced and the active point of the positive electrode active material can be reduced. Therefore, electrolytic solution decomposition can be suppressed and cycle characteristics can be improved.

  Since the primary particle has a polyhedron shape with more than eight faces, the primary particles can have a plurality of types of crystal faces. That is, the primary particles can have multiple functions such as a Mn elution suppression surface, a Li diffusion promotion surface, and an activity suppression surface.

  The transition metal carbonate can be co-precipitated from a solution containing a transition metal salt containing manganese (Mn) and a carbonate without adding a precipitating agent or a complexing agent. Therefore, precursor particles can be produced without adding an additive such as a precipitating agent or a complexing agent at the time of carbonate precipitation.

  Since no additive for crystal control remains in the positive electrode active material, the mass per unit electrode and the capacity per unit electrode volume can be improved. Since the positive electrode active material can be produced without increasing the number of steps, an increase in production cost can be suppressed.

  By producing the positive electrode active material via the carbonate, the shape of the primary particles can be easily controlled. Therefore, it becomes easy to make the shape of the primary particle a polyhedron having more than eight faces (for example, a tetrahedron).

(Modification)
The positive electrode active material may include two or more positive electrode active materials capable of inserting and extracting lithium (Li). That is, the composite oxide having the above-mentioned spinel structure and one or more other positive electrode active materials may be included. As the positive electrode active material other than the composite oxide described above, for example, lithium-containing compounds such as lithium oxide, lithium phosphorus oxide, lithium sulfide, or an intercalation compound containing lithium are suitable, and two or more of these are mixed. May be used. In order to increase the energy density, a lithium-containing compound containing lithium, a transition metal element, and oxygen (O) is preferable. Examples of such a lithium-containing compound include a lithium composite oxide having a layered rock salt structure shown in Formula (A) and a lithium composite phosphate having an olivine structure shown in Formula (B). Can be mentioned. It is more preferable that the lithium-containing compound includes at least one member selected from the group consisting of cobalt (Co), nickel (Ni), manganese (Mn), and iron (Fe) as a transition metal element. Examples of such a lithium-containing compound include a lithium composite oxide having a layered rock salt type structure represented by the formula (C), formula (D), or formula (E), and a spinel type compound represented by the formula (F). Examples thereof include a lithium composite oxide having a structure, or a lithium composite phosphate having an olivine structure shown in the formula (G). Specifically, LiNi _0.50 Co _0.20 Mn _0.30 O ₂ , Li _a CoO ₂ (A≈1), Li _b NiO ₂ (b≈1), Li _c1 Ni _c2 Co _1-c2 O ₂ (c1≈1, 0 <c2 <1), Li _d Mn ₂ O ₄ (d≈1) or Li _e FePO ₄ (e≈1).

_{Li p Ni (1-qr)} Mn q M1 r O (2-y) X z ··· (A)
(In the formula (A), M1 represents at least one element selected from Groups 2 to 15 excluding nickel (Ni) and manganese (Mn). X represents Group 16 other than oxygen (O)) It represents at least one of elements and group 17. Elements p, q, y, and z are 0 ≦ p ≦ 1.5, 0 ≦ q ≦ 1.0, 0 ≦ r ≦ 1.0, −0.10. ≦ y ≦ 0.20 and 0 ≦ z ≦ 0.2.

Li _a M2 _b PO ₄ (B)
(In the formula (B), M2 represents at least one element selected from Groups 2 to 15. a and b are 0 ≦ a ≦ 2.0 and 0.5 ≦ b ≦ 2.0. It is a value within the range.)

Li _f Mn _(1-gh) Ni _g M3 _h O _(2-j) F _k (C)
(However, in formula (C), M3 is cobalt (Co), magnesium (Mg), aluminum (Al), boron (B), titanium (Ti), vanadium (V), chromium (Cr), iron (Fe ), Copper (Cu), zinc (Zn), zirconium (Zr), molybdenum (Mo), tin (Sn), calcium (Ca), strontium (Sr) and tungsten (W) F, g, h, j and k are 0.8 ≦ f ≦ 1.2, 0 <g <0.5, 0 ≦ h ≦ 0.5, g + h <1, −0.1 ≦ j. ≦ 0.2, 0 ≦ k ≦ 0.1 (The composition of lithium varies depending on the state of charge and discharge, and the value of f represents the value in the complete discharge state.)

Li _m Ni _(1-n) M4 _n O _(2-p) F _q (D)
(However, in formula (D), M4 is cobalt (Co), manganese (Mn), magnesium (Mg), aluminum (Al), boron (B), titanium (Ti), vanadium (V), chromium (Cr ), Iron (Fe), copper (Cu), zinc (Zn), molybdenum (Mo), tin (Sn), calcium (Ca), strontium (Sr), and tungsten (W). M, n, p and q are 0.8 ≦ m ≦ 1.2, 0.005 ≦ n ≦ 0.5, −0.1 ≦ p ≦ 0.2, 0 ≦ q ≦ 0.1. (Note that the composition of lithium varies depending on the state of charge and discharge, and the value of m represents a value in a fully discharged state.)

Li _r Co _(1-s) M5 _s O _{(2-t) Fu} (E)
(However, in formula (E), M5 is nickel (Ni), manganese (Mn), magnesium (Mg), aluminum (Al), boron (B), titanium (Ti), vanadium (V), chromium (Cr ), Iron (Fe), copper (Cu), zinc (Zn), molybdenum (Mo), tin (Sn), calcium (Ca), strontium (Sr), and tungsten (W). R, s, t, and u are ranges of 0.8 ≦ r ≦ 1.2, 0 ≦ s <0.5, −0.1 ≦ t ≦ 0.2, and 0 ≦ u ≦ 0.1. (Note that the composition of lithium varies depending on the state of charge and discharge, and the value of r represents a value in a fully discharged state.)

Li _v Mn _2-w M6 _w O _x F _y (F)
(However, in formula (F), M6 is cobalt (Co), nickel (Ni), magnesium (Mg), aluminum (Al), boron (B), titanium (Ti), vanadium (V), chromium (Cr ), Iron (Fe), copper (Cu), zinc (Zn), molybdenum (Mo), tin (Sn), calcium (Ca), strontium (Sr), and tungsten (W). V, w, x, and y are in the range of 0.9 ≦ v ≦ 1.1, 0 ≦ w ≦ 0.6, 3.7 ≦ x ≦ 4.1, and 0 ≦ y ≦ 0.1. (Note that the composition of lithium varies depending on the state of charge and discharge, and the value of v represents the value in a fully discharged state.)

Li _z M7PO ₄ (G)
(However, in formula (G), M7 is cobalt (Co), manganese (Mn), iron (Fe), nickel (Ni), magnesium (Mg), aluminum (Al), boron (B), titanium (Ti ), Vanadium (V), niobium (Nb), copper (Cu), zinc (Zn), molybdenum (Mo), calcium (Ca), strontium (Sr), tungsten (W) and zirconium (Zr) Z represents a value in a range of 0.9 ≦ z ≦ 1.1, wherein the composition of lithium varies depending on the state of charge and discharge, and the value of z is a value in a fully discharged state. Represents.)

In addition to these, examples of the positive electrode active material capable of inserting and extracting lithium include inorganic compounds not containing lithium, such as MnO ₂ , V ₂ O ₅ , V ₆ O ₁₃ , NiS, and MoS.

  The positive electrode material capable of inserting and extracting lithium may be other than the above. Moreover, the positive electrode active material illustrated above may be mixed 2 or more types by arbitrary combinations.

<2. Second Embodiment>
[Battery configuration]
FIG. 1 is a cross-sectional view illustrating a configuration example of a nonaqueous electrolyte secondary battery according to a second embodiment of the present technology. This non-aqueous electrolyte secondary battery has a so-called lithium ion secondary battery that has a high output potential of, for example, 5 V class, and whose negative electrode capacity is represented by a capacity component due to insertion and extraction of lithium (Li) as an electrode reactant. It is a battery. This non-aqueous electrolyte secondary battery is a so-called cylindrical type, and a pair of strip-like positive electrode 21 and strip-like negative electrode 22 are laminated and wound inside a substantially hollow cylindrical battery can 11 via a separator 23. The wound electrode body 20 is rotated. The battery can 11 is made of iron (Fe) plated with nickel (Ni), and has one end closed and the other end open. An electrolyte is injected into the battery can 11 and impregnated in the separator 23. In addition, a pair of insulating plates 12 and 13 are respectively disposed perpendicular to the winding peripheral surface so as to sandwich the winding electrode body 20.

  At the open end of the battery can 11, a battery lid 14, a safety valve mechanism 15 and a thermal resistance element (PTC element) 16 provided inside the battery lid 14 are provided via a sealing gasket 17. It is attached by caulking. Thereby, 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 reversed and wound around the battery lid 14. The electrical connection with the electrode body 20 is cut off. The sealing gasket 17 is made of, for example, an insulating material, and the surface 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 (Al) or the like is connected to the positive electrode 21 of the spirally 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 and electrically connected to the battery can 11.

  FIG. 2 is an enlarged cross-sectional view showing a part of the spirally wound electrode body 20 shown in FIG. Hereinafter, the positive electrode 21, the negative electrode 22, the separator 23, and the electrolytic solution constituting the secondary battery will be sequentially described with reference to FIG.

(Positive electrode)
The positive electrode 21 has, for example, a structure in which a positive electrode active material layer 21B is provided on both surfaces of a positive electrode current collector 21A. Although not shown, the positive electrode active material layer 21B may be provided only on one surface 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. The positive electrode active material layer 21B includes, for example, one or more positive electrode active materials capable of inserting and extracting lithium, and a conductive agent such as graphite and a binder such as polyvinylidene fluoride as necessary. It is composed of an adhesive.

  As the positive electrode active material capable of inserting and extracting lithium, those described in the first embodiment and the modifications thereof are used.

(Negative electrode)
The negative electrode 22 has, for example, a structure in which a negative electrode active material layer 22B is provided on both surfaces of a negative electrode current collector 22A. Although not shown, the negative electrode active material layer 22B may be provided only on one surface of the negative electrode current collector 22A. The anode current collector 22A is made of, for example, a metal foil such as a copper foil.

  The negative electrode active material layer 22B includes one or more negative electrode materials capable of inserting and extracting lithium as the negative electrode active material, and the positive electrode active material layer 21B as necessary. It is comprised including the binder similar to.

  In this secondary battery, the electrochemical equivalent of the negative electrode material capable of inserting and extracting lithium is larger than the electrochemical equivalent of the positive electrode 21, and lithium metal is deposited on the negative electrode 22 during charging. It is supposed not to.

  Examples of the negative electrode material capable of inserting and extracting lithium include non-graphitizable carbon, graphitizable carbon, graphite, pyrolytic carbons, cokes, glassy carbons, and fired organic polymer compounds And carbon materials such as carbon fiber and activated carbon. Among these, examples of coke include pitch coke, needle coke, and petroleum coke. An organic polymer compound fired body refers to a carbonized material obtained by firing a polymer material such as phenol resin or furan resin at an appropriate temperature, and part of it is non-graphitizable carbon or graphitizable carbon. Some are classified as: Examples of the polymer material include polyacetylene and polypyrrole. These carbon materials are preferable because the change in crystal structure that occurs during charge and discharge is very small, a high charge and discharge capacity can be obtained, and good cycle characteristics can be obtained. In particular, graphite is preferable because it has a high electrochemical equivalent and can provide a high energy density. Further, non-graphitizable carbon is preferable because excellent 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 a high energy density of the battery can be easily realized.

  Examples of the negative electrode material capable of inserting and extracting lithium include materials capable of inserting and extracting lithium and containing at least one of a metal element and a metalloid element as a constituent element. This is because a high energy density can be obtained by using such a material. In particular, the use with a carbon material is more preferable because a high energy density can be obtained and excellent cycle characteristics can be obtained. The negative electrode material may be a single element, alloy or compound of a metal element or metalloid element, or may have at least a part of one or more of these phases. In the present technology, the alloy includes an alloy including one or more metal elements and one or more metalloid elements in addition to an alloy composed of two or more metal elements. Moreover, the nonmetallic element may be included. Some of the structures include a solid solution, a eutectic (eutectic mixture), an intermetallic compound, or two or more of them.

  Examples of metal elements or metalloid elements constituting the negative electrode material include magnesium (Mg), boron (B), aluminum (Al), gallium (Ga), indium (In), silicon (Si), and germanium (Ge). ), Tin (Sn), lead (Pb), bismuth (Bi), cadmium (Cd), silver (Ag), zinc (Zn), hafnium (Hf), zirconium (Zr), yttrium (Y), palladium (Pd) ) Or platinum (Pt). These may be crystalline or amorphous.

  Among these, as the negative electrode material, a material containing a 4B group metal element or a semimetal element in the short-period type periodic table as a constituent element is preferable, and at least one of silicon (Si) and tin (Sn) is particularly preferable. It is included as an element. This is because silicon (Si) and tin (Sn) have a large ability to occlude and release lithium (Li), and a high energy density can be obtained.

  As an alloy of tin (Sn), for example, as a second constituent element other than tin (Sn), silicon (Si), nickel (Ni), copper (Cu), iron (Fe), cobalt (Co), manganese (Mn), zinc (Zn), indium (In), silver (Ag), titanium (Ti), germanium (Ge), bismuth (Bi), antimony (Sb), and chromium (Cr) The thing containing at least 1 sort is mentioned. As an alloy of silicon (Si), for example, as a second constituent element other than silicon (Si), tin (Sn), nickel (Ni), copper (Cu), iron (Fe), cobalt (Co), manganese (Mn), zinc (Zn), indium (In), silver (Ag), titanium (Ti), germanium (Ge), bismuth (Bi), antimony (Sb), and chromium (Cr). The thing containing 1 type is mentioned.

  Examples of the tin (Sn) compound or silicon (Si) compound include those containing oxygen (O) or carbon (C). In addition to tin (Sn) or silicon (Si), the above-described compounds are used. Two constituent elements may be included.

  Among these, as the negative electrode material, cobalt (Co), tin (Sn), and carbon (C) are included as constituent elements, and the carbon content is 9.9 mass% or more and 29.7 mass% or less. And the SnCoC containing material whose ratio of cobalt (Co) with respect to the sum total of tin (Sn) and cobalt (Co) is 30 mass% or more and 70 mass% or less is preferable. This is because, in such a composition range, a high energy density can be obtained and excellent cycle characteristics can be obtained.

  This SnCoC-containing material may further contain other constituent elements as necessary. Examples of other constituent elements include silicon (Si), iron (Fe), nickel (Ni), chromium (Cr), indium (In), niobium (Nb), germanium (Ge), titanium (Ti), and molybdenum. (Mo), aluminum (Al), phosphorus (P), gallium (Ga) or bismuth (Bi) are preferable and may contain two or more. This is because the capacity or cycle characteristics can be further improved.

  This SnCoC-containing material has a phase containing tin (Sn), cobalt (Co), and carbon (C), and this phase has a low crystallinity or an amorphous structure. It is preferable. In this SnCoC-containing material, it is preferable that at least a part of carbon (C) as a constituent element is bonded to a metal element or a metalloid element as another constituent element. The decrease in cycle characteristics is considered to be due to aggregation or crystallization of tin (Sn) or the like. However, the combination of carbon (C) with other elements suppresses such aggregation or crystallization. Because it can.

Further, examples of the negative electrode material capable of inserting and extracting lithium include other metal compounds or polymer materials. Other metal compounds include oxides such as lithium titanate (Li ₄ Ti ₅ O ₁₂ ), manganese dioxide (MnO ₂ ), vanadium oxide (V ₂ O ₅ , V ₆ O ₁₃ ), nickel sulfide (NiS), Examples thereof include sulfides such as molybdenum sulfide (MoS ₂ ) and lithium nitrides such as lithium nitride (Li ₃ N), and examples of the polymer material include polyacetylene, polyaniline, and polypyrrole.

(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. As the separator 23, for example, a porous film made of a synthetic resin such as polytetrafluoroethylene, polypropylene, or polyethylene, or a porous film made of a ceramic may be used as a single layer or a plurality of stacked layers. In particular, the separator 23 is preferably a polyolefin porous film. It is because it is excellent in the short-circuit prevention effect and can improve the safety of the battery by the shutdown effect. Further, as the separator 23, a separator in which a porous resin layer such as polyvinylidene fluoride (PVdF) or polytetrafluoroethylene (PTFE) is formed on a microporous film such as polyolefin may be used.

(Electrolyte)
The separator 23 is impregnated with an electrolytic solution that is a liquid electrolyte. This electrolytic solution contains a solvent and an electrolyte salt dissolved in the solvent.

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

  As the solvent, in addition to these cyclic carbonates, a chain carbonate such as diethyl carbonate, dimethyl carbonate, ethylmethyl carbonate or methylpropyl carbonate is preferably mixed and used. This is because high ionic conductivity can be obtained.

  It is preferable that the solvent further contains 2,4-difluoroanisole or vinylene carbonate. This is because 2,4-difluoroanisole can improve discharge capacity, and vinylene carbonate can improve cycle characteristics. Therefore, it is preferable to use a mixture of these because the discharge capacity and cycle characteristics can be improved.

  In addition to these, examples of the solvent include butylene carbonate, γ-butyrolactone, γ-valerolactone, 1,2-dimethoxyethane, tetrahydrofuran, 2-methyltetrahydrofuran, 1,3-dioxolane, 4-methyl-1,3- Dioxolane, methyl acetate, methyl propionate, acetonitrile, glutaronitrile, adiponitrile, methoxyacetonitrile, 3-methoxypropironitrile, N, N-dimethylformamide, N-methylpyrrolidinone, N-methyloxazolidinone, N, N-dimethyl Examples include imidazolidinone, nitromethane, nitroethane, sulfolane, dimethyl sulfoxide, and trimethyl phosphate.

  A compound obtained by substituting at least a part of hydrogen in these non-aqueous solvents with fluorine may be preferable because the reversibility of the electrode reaction may be improved depending on the type of electrode to be combined.

As electrolyte salt, lithium salt is mentioned, for example, 1 type may be used independently, and 2 or more types may be mixed and used for it. 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 [oxolato-O, O ′] lithium borate, lithium bisoxalate borate, or LiBr. Among them, LiPF ₆ is preferable because it can obtain high ion conductivity and can improve cycle characteristics.

[Battery manufacturing method]
Next, an example of a method for manufacturing a nonaqueous electrolyte secondary battery according to the second embodiment of the present technology will be described.
First, for example, a positive electrode active material, a conductive agent, and a binder are mixed to prepare a positive electrode mixture, and the positive electrode mixture is dispersed in a solvent such as N-methyl-2-pyrrolidone to obtain a paste-like material. A positive electrode mixture slurry is prepared. Next, this positive electrode mixture slurry is applied to the positive electrode current collector 21 </ b> A, the solvent is dried, and the positive electrode active material layer 21 </ b> B is formed by compression molding with a roll press or the like, thereby forming the positive electrode 21.

  Further, for example, a negative electrode active material and a binder are mixed to prepare a negative electrode mixture, and this negative electrode mixture is dispersed in a solvent such as N-methyl-2-pyrrolidone to obtain a paste-like negative electrode mixture slurry Is made. Next, the negative electrode mixture slurry is applied to the negative electrode current collector 22A, the solvent is dried, and the negative electrode active material layer 22B is formed by compression molding using a roll press or the like, 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 through the separator 23. Next, the front end of the positive electrode lead 25 is welded to the safety valve mechanism 15, and the front end of the negative electrode lead 26 is welded to the battery can 11, and the wound positive electrode 21 and negative electrode 22 are connected with the pair of insulating plates 12 and 13. It is housed inside the sandwiched battery can 11. Next, after the positive electrode 21 and the negative electrode 22 are accommodated in the battery can 11, the electrolytic solution is injected into the battery can 11 and impregnated in the separator 23. Next, the battery lid 14, the safety valve mechanism 15, and the heat sensitive resistance element 16 are fixed to the opening end of the battery can 11 by caulking through a sealing gasket 17. Thereby, the secondary battery shown in FIG. 1 is obtained.

  In the nonaqueous electrolyte secondary battery according to the second embodiment, since the positive electrode 21 includes the positive electrode active material according to the first embodiment described above, the cycle characteristics can be improved.

<3. Third Embodiment>
[Battery configuration]
FIG. 3 is an exploded perspective view showing a configuration example of the nonaqueous electrolyte secondary battery according to the third embodiment of the present technology. In this secondary battery, a wound electrode body 30 to which a positive electrode lead 31 and a negative electrode lead 32 are attached is accommodated in a film-like exterior member 40, and can be reduced in size, weight, and thickness. ing.

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

  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 together in this order. For example, the exterior member 40 is disposed so that the polyethylene film side and the wound electrode body 30 face each other, and the outer edge portions are in close contact with each other by fusion bonding or an adhesive. An adhesive film 41 is inserted between the exterior member 40 and the positive electrode lead 31 and the negative electrode lead 32 to prevent intrusion of outside air. 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 laminated film having another structure, a polymer film such as polypropylene, or a metal film instead of the above-described aluminum laminated film.

  4 is a cross-sectional view taken along line IV-IV of the spirally wound electrode body 30 shown in FIG. The wound electrode body 30 is obtained by stacking and winding a positive electrode 33 and a negative electrode 34 with a separator 35 and an electrolyte layer 36 interposed therebetween, and the outermost peripheral portion is protected by a protective tape 37.

  The positive electrode 33 has a structure in which a positive electrode active material layer 33B is provided on one or both surfaces of a positive electrode current collector 33A. The negative electrode 34 has a structure in which a negative electrode active material layer 34B is provided on one surface or both surfaces of a negative electrode current collector 34A, and the negative electrode active material layer 34B and the positive electrode active material layer 33B are arranged to face each other. Yes. The configurations of the positive electrode current 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 respectively the positive electrode current collector 21A, the positive electrode active material layer 21B, and the negative electrode 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 includes an electrolytic solution and a polymer compound serving as a holding body that holds the electrolytic solution, and has a so-called gel shape. The gel electrolyte layer 36 is preferable because high ion conductivity can be obtained and battery leakage can be prevented. The composition of the electrolytic solution is the same as that of the secondary battery 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. , Polyvinyl acetate, polyvinyl alcohol, polymethyl methacrylate, polyacrylic acid, polymethacrylic acid, styrene-butadiene rubber, nitrile-butadiene rubber, polystyrene or polycarbonate. In particular, polyacrylonitrile, polyvinylidene fluoride, polyhexafluoropropylene or polyethylene oxide is preferable from the viewpoint of electrochemical stability.

[Battery manufacturing method]
Next, an example of a method for manufacturing a nonaqueous electrolyte secondary battery according to the third embodiment of the present technology 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 portion of the positive electrode current collector 33A by welding, and the negative electrode lead 32 is attached to the end portion 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 a separator 35 to form a laminated body, and then the laminated body is wound in the longitudinal direction, and a protective tape 37 is attached to the outermost peripheral portion. The wound electrode body 30 is formed by bonding. Finally, for example, the wound electrode body 30 is sandwiched between the exterior members 40, and the outer edges of the exterior members 40 are sealed and sealed by heat fusion or the like. 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. Thereby, the secondary battery shown in FIG. 3 and FIG. 4 is obtained.

  Further, this secondary battery may be manufactured as follows. First, the positive electrode 33 and the negative electrode 34 are produced 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 a protective tape 37 is adhered to the outermost peripheral portion to form a wound body that is a precursor of the wound electrode body 30. Next, the wound body is sandwiched between the exterior members 40, and the outer peripheral edge except for one side is heat-sealed to form a bag shape, which is then stored inside the exterior member 40. Next, an electrolyte composition including a solvent, an electrolyte salt, a monomer that is a raw material of the polymer compound, a polymerization initiator, and other materials such as a polymerization inhibitor as necessary is prepared, and the exterior member Inject into 40.

  Next, after injecting the electrolyte composition into the exterior member 40, the opening of the exterior member 40 is heat-sealed in a vacuum atmosphere and sealed. Next, the gelled electrolyte layer 36 is formed by applying heat to polymerize the monomer to obtain a polymer compound. Thus, the secondary battery shown in FIG. 3 is obtained.

  The operation and effect of the nonaqueous electrolyte secondary battery according to the third embodiment are the same as those of the nonaqueous electrolyte secondary battery according to the second embodiment.

<4. Fourth Embodiment>
(Example of battery pack)
FIG. 5 is a block diagram illustrating a circuit configuration example when a nonaqueous electrolyte secondary battery of the present technology (hereinafter appropriately referred to as a secondary battery) is applied to a battery pack. The battery pack includes a switch unit 304 including an assembled battery 301, an exterior, a charge control switch 302a, and a discharge control switch 303a, a current detection resistor 307, a temperature detection element 308, and a control unit 310.

  In addition, the battery pack includes a positive electrode terminal 321 and a negative electrode terminal 322. During charging, the positive electrode terminal 321 and the negative electrode terminal 322 are connected to the positive electrode terminal and the negative electrode terminal of the charger, respectively, and charging is performed. Further, when the electronic device is used, the positive electrode terminal 321 and the negative electrode terminal 322 are connected to the positive electrode terminal and the negative electrode terminal of the electronic device, respectively, and discharge is performed.

  The assembled battery 301 is formed by connecting a plurality of secondary batteries 301a in series and / or in parallel. The secondary battery 301a is a secondary battery of the present technology. In addition, in FIG. 5, the case where six secondary batteries 301a are connected in two parallel three series (2P3S) is shown as an example, but in addition, n parallel m series (n and m are integers) Any connection method may be used.

  The switch unit 304 includes a charge control switch 302a and a diode 302b, and a discharge control switch 303a and a diode 303b, and is controlled by the control unit 310. The diode 302b has a reverse polarity with respect to the charging current flowing from the positive terminal 321 in the direction of the assembled battery 301 and the forward polarity with respect to the discharging current flowing from the negative terminal 322 in the direction of the assembled battery 301. The diode 303b has a forward polarity with respect to the charging current and a reverse polarity with respect to the discharging current. In the example, the switch portion is provided on the + side, but may be provided on the − side.

  The charge control switch 302 a is turned off when the battery voltage becomes the overcharge detection voltage, and is controlled by the charge / discharge control unit so that the charge current does not flow in the current path of the assembled battery 301. After the charge control switch is turned off, only discharging is possible through the diode 302b. Further, it is turned off when a large current flows during charging, and is controlled by the control unit 310 so that the charging current flowing in the current path of the assembled battery 301 is cut off.

  The discharge control switch 303a is turned off when the battery voltage becomes the overdischarge detection voltage, and is controlled by the control unit 310 so that the discharge current does not flow through the current path of the assembled battery 301. After the discharge control switch 303a is turned off, only charging is possible via the diode 303b. Further, it is turned off when a large current flows during discharging, and is controlled by the control unit 310 so as to cut off the discharging current flowing in the current path of the assembled battery 301.

  The temperature detection element 308 is, for example, a thermistor, is provided in the vicinity of the assembled battery 301, measures the temperature of the assembled battery 301, and supplies the measured temperature to the control unit 310. The voltage detection unit 311 measures the voltage of the assembled battery 301 and each secondary battery 301a constituting the assembled battery 301, performs A / D conversion on the measured voltage, and supplies the voltage to the control unit 310. The current measurement unit 313 measures the current using the current detection resistor 307 and supplies this measurement current to the control unit 310.

  The switch control unit 314 controls the charge control switch 302a and the discharge control switch 303a of the switch unit 304 based on the voltage and current input from the voltage detection unit 311 and the current measurement unit 313. The switch control unit 314 sends a control signal to the switch unit 304 when any voltage of the secondary battery 301a falls below the overcharge detection voltage or overdischarge detection voltage, or when a large current flows suddenly. By sending, overcharge, overdischarge, and overcurrent charge / discharge are prevented.

  Here, for example, when the secondary battery 301a is a lithium ion secondary battery, the overcharge detection voltage is determined to be, for example, 4.20V ± 0.05V, and the overdischarge detection voltage is determined to be, for example, 2.4V ± 0.1V. It is done.

  As the charge / discharge switch, for example, a semiconductor switch such as a MOSFET can be used. In this case, the parasitic diode of the MOSFET functions as the diodes 302b and 303b. When a P-channel FET is used as the charge / discharge switch, the switch control unit 314 supplies control signals DO and CO to the gates of the charge control switch 302a and the discharge control switch 303a, respectively. When the charge control switch 302a and the discharge control switch 303a are P-channel type, they are turned on by a gate potential that is lower than the source potential by a predetermined value or more. That is, in normal charging and discharging operations, the control signals CO and DO are set to the low level, and the charging control switch 302a and the discharging control switch 303a are turned on.

  For example, during overcharge or overdischarge, the control signals CO and DO are set to a high level, and the charge control switch 302a and the discharge control switch 303a are turned off.

  The memory 317 includes a RAM and a ROM, and includes, for example, an EPROM (Erasable Programmable Read Only Memory) that is a nonvolatile memory. In the memory 317, the numerical value calculated by the control unit 310, the internal resistance value of the battery in the initial state of each secondary battery 301a measured in the manufacturing process, and the like are stored in advance, and can be appropriately rewritten. . (Also, by storing the full charge capacity of the secondary battery 301a, for example, the remaining capacity can be calculated together with the control unit 310.

  The temperature detection unit 318 measures the temperature using the temperature detection element 308, performs charge / discharge control during abnormal heat generation, and performs correction in the calculation of the remaining capacity.

<5. Fifth Embodiment>
The nonaqueous electrolyte secondary battery and the battery pack using the nonaqueous electrolyte battery described above can be used for mounting or supplying power to devices such as electronic devices, electric vehicles, and power storage devices.

  Examples of electronic devices include notebook computers, PDAs (personal digital assistants), mobile phones, cordless phones, video movies, digital still cameras, electronic books, electronic dictionaries, music players, radios, headphones, game consoles, navigation systems, Memory card, pacemaker, hearing aid, electric tool, electric shaver, refrigerator, air conditioner, TV, stereo, water heater, microwave oven, dishwasher, washing machine, dryer, lighting equipment, toys, medical equipment, robots, road conditioners, traffic lights Etc.

  In addition, examples of the electric vehicle include a railway vehicle, a golf cart, an electric cart, an electric vehicle (including a hybrid vehicle), and the like, and are used as a driving power source or an auxiliary power source.

  Examples of the power storage device include a power storage power source for buildings such as houses or power generation facilities.

  Below, the specific example of the electrical storage system using the electrical storage apparatus to which the nonaqueous electrolyte secondary battery of this technique mentioned above is applied among the application examples mentioned above is demonstrated.

  This power storage system has the following configuration, for example. The first power storage system is a power storage system in which a power storage device is charged by a power generation device that generates power from renewable energy. The second power storage system is a power storage system that includes a power storage device and supplies power to an electronic device connected to the power storage device. The third power storage system is an electronic device that receives power supply from the power storage device. These power storage systems are implemented as a system for efficiently supplying power in cooperation with an external power supply network.

  Furthermore, the fourth power storage system includes an electric vehicle having a conversion device that receives power supplied from the power storage device and converts the power into a driving force of the vehicle, and a control device that performs information processing related to vehicle control based on information related to the power storage device. It is. The fifth power storage system is a power system that includes a power information transmission / reception unit that transmits / receives signals to / from other devices via a network, and performs charge / discharge control of the power storage device described above based on information received by the transmission / reception unit. . The sixth power storage system is a power system that receives power from the power storage device described above or supplies power from the power generation device or the power network to the power storage device. Hereinafter, the power storage system will be described.

(Power storage system in a house as an application example)
An example in which a power storage device using the nonaqueous electrolyte secondary battery of the present technology is applied to a residential power storage system will be described with reference to FIG. For example, in the power storage system 100 for the house 101, electric power is stored from the centralized power system 102 such as the thermal power generation 102a, the nuclear power generation 102b, and the hydroelectric power generation 102c through the power network 109, the information network 112, the smart meter 107, the power hub 108, and the like. Supplied to the device 103. At the same time, power is supplied to the power storage device 103 from an independent power source such as the home power generation device 104. The electric power supplied to the power storage device 103 is stored. Electric power used in the house 101 is fed using the power storage device 103. The same power storage system can be used not only for the house 101 but also for buildings.

  The house 101 is provided with a power generation device 104, a power consumption device 105, a power storage device 103, a control device 110 that controls each device, a smart meter 107, and a sensor 111 that acquires various types of information. Each device is connected by a power network 109 and an information network 112. A solar cell, a fuel cell, or the like is used as the power generation device 104, and the generated power is supplied to the power consumption device 105 and / or the power storage device 103. The power consuming device 105 is a refrigerator 105a, an air conditioner 105b, a television receiver 105c, a bath 105d, or the like. Furthermore, the electric power consumption device 105 includes an electric vehicle 106. The electric vehicle 106 is an electric vehicle 106a, a hybrid car 106b, and an electric motorcycle 106c.

  The nonaqueous electrolyte secondary battery of the present technology is applied to the power storage device 103. The nonaqueous electrolyte secondary battery of the present technology may be configured by, for example, the above-described lithium ion secondary battery. The smart meter 107 has a function of measuring the usage amount of commercial power and transmitting the measured usage amount to an electric power company. The power network 109 may be one or a combination of DC power supply, AC power supply, and non-contact power supply.

  The various sensors 111 are, for example, human sensors, illuminance sensors, object detection sensors, power consumption sensors, vibration sensors, contact sensors, temperature sensors, infrared sensors, and the like. Information acquired by various sensors 111 is transmitted to the control device 110. Based on the information from the sensor 111, the weather state, the state of a person, and the like can be grasped, and the power consumption device 105 can be automatically controlled to minimize the energy consumption. Furthermore, the control device 110 can transmit information regarding the house 101 to an external power company or the like via the Internet.

  The power hub 108 performs processing such as branching of power lines and DC / AC conversion. Communication methods of the information network 112 connected to the control device 110 include a method using a communication interface such as UART (Universal Asynchronous Receiver-Transceiver), and wireless communication such as Bluetooth, ZigBee, and Wi-Fi. There is a method of using a sensor network according to the standard. The Bluetooth method is applied to multimedia communication and can perform one-to-many connection communication. ZigBee uses the physical layer of IEEE (Institute of Electrical and Electronics Engineers) 802.15.4. IEEE 802.15.4 is the name of a short-range wireless network standard called PAN (Personal Area Network) or W (Wireless) PAN.

  The control device 110 is connected to an external server 113. The server 113 may be managed by any one of the house 101, the power company, and the service provider. The information transmitted and received by the server 113 is, for example, information related to power consumption information, life pattern information, power charges, weather information, natural disaster information, and power transactions. These pieces of information may be transmitted / received from a power consuming device in the home (for example, a television receiver) or may be transmitted / received from a device outside the home (for example, a mobile phone). Such information may be displayed on a device having a display function, such as a television receiver, a mobile phone, or a PDA (Personal Digital Assistants).

  The control device 110 that controls each unit includes 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 103 in this example. The control device 110 is connected to the power storage device 103, the home power generation device 104, the power consumption device 105, the various sensors 111, the server 113 and the information network 112, and adjusts, for example, the amount of commercial power used and the amount of power generation. It has a function. In addition, you may provide the function etc. which carry out an electric power transaction in an electric power market.

  As described above, the electric power can be stored not only in the centralized power system 102 such as the thermal power 102a, the nuclear power 102b, and the hydropower 102c but also in the power storage device 103 from the home power generation device 104 (solar power generation, wind power generation). it can. Therefore, even if the generated power of the home power generation device 104 fluctuates, it is possible to perform control such that the amount of power to be sent to the outside is constant or discharge is performed as necessary. For example, the electric power obtained by solar power generation is stored in the power storage device 103, and midnight power with a low charge is stored in the power storage device 103 at night, and the power stored by the power storage device 103 is discharged during a high daytime charge. You can also use it.

  In this example, the example in which the control device 110 is stored in the power storage device 103 has been described. However, the control device 110 may be stored in the smart meter 107 or may be configured independently. Furthermore, the power storage system 100 may be used for a plurality of homes in an apartment house, or may be used for a plurality of detached houses.

(Power storage system in vehicles as an application example)
An example in which the present technology is applied to a power storage system for a vehicle will be described with reference to FIG. FIG. 7 schematically shows an example of the configuration of a hybrid vehicle that employs a series hybrid system to which the present technology is applied. A series hybrid system is a car that runs on an electric power driving force conversion device using electric power generated by a generator driven by an engine or electric power once stored in a battery.

  The hybrid vehicle 200 includes an engine 201, a generator 202, a power driving force conversion device 203, driving wheels 204a, driving wheels 204b, wheels 205a, wheels 205b, a battery 208, a vehicle control device 209, various sensors 210, and a charging port 211. Is installed. The above-described nonaqueous electrolyte secondary battery of the present technology is applied to the battery 208.

  The hybrid vehicle 200 runs using the power driving force conversion device 203 as a power source. An example of the power driving force conversion device 203 is a motor. The electric power / driving force converter 203 is operated by the electric power of the battery 208, and the rotational force of the electric power / driving force converter 203 is transmitted to the driving wheels 204a and 204b. In addition, by using a direct current-alternating current (DC-AC) or reverse conversion (AC-DC conversion) where necessary, the power driving force conversion device 203 can be applied to either an AC motor or a DC motor. The various sensors 210 control the engine speed via the vehicle control device 209 and control the opening (throttle opening) of a throttle valve (not shown). The various sensors 210 include a speed sensor, an acceleration sensor, an engine speed sensor, and the like.

  The rotational force of the engine 201 is transmitted to the generator 202, and the electric power generated by the generator 202 by the rotational force can be stored in the battery 208.

  When the hybrid vehicle 200 decelerates by a braking mechanism (not shown), the resistance force at the time of deceleration is applied as a rotational force to the power driving force conversion device 203, and the regenerative electric power generated by the power driving force conversion device 203 by this rotational force is used as the battery 208. Accumulated in.

  The battery 208 can be connected to a power source external to the hybrid vehicle 200 to receive power supply from the external power source using the charging port 211 as an input port and store the received power.

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

  In the above description, a series hybrid vehicle that runs on a motor using electric power generated by a generator that is driven by an engine or electric power that is temporarily stored in a battery has been described as an example. However, the present technology is also effective for a parallel hybrid vehicle in which the engine and motor outputs are both driving sources, and the system is switched between the three modes of driving with only the engine, driving with the motor, and engine and motor. Applicable. Furthermore, the present technology can be effectively applied to a so-called electric vehicle that travels only by a drive motor without using an engine.

  Hereinafter, the present technology will be specifically described by way of examples. However, the present technology is not limited only to these examples.

Example 1
<Nickel Manganese Precursor Production Process>
First, ammonia water having a concentration of 3% was charged into a 2 L cylindrical reaction vessel, and the temperature was kept at 50 ° C. and stirred at a constant speed. Next, three types of coprecipitation additive liquid (chemical) were added to the reaction vessel to produce nickel manganese coprecipitation particles mainly composed of nickel manganese carbonate (Ni _0.25 Mn _0.75 CO ₃ ). Below, three types of coprecipitation addition liquid (1)-(3) used in this process and its addition conditions are shown.
Coprecipitation liquid (1):
Type: A mixed aqueous solution of 1.5 mol / l of manganese sulfate and nickel sulfate (Ni: Mn atomic ratio is 1: 3) was used.
Addition conditions: The reaction vessel was continuously added at a flow rate of 2 cc / min.
Coprecipitation additive (2)
Type: Ammonia water having a concentration of 5% was used.
Addition conditions: Continuously added to the reaction vessel at a flow rate of 0.27 cc / min.
Coprecipitation additive (3)
Type: A sodium carbonate aqueous solution having a concentration of 2 mol / l was used.
Addition conditions: Added to the reaction vessel intermittently so that the pH was 8.

Next, the coprecipitation reaction liquid containing nickel manganese coprecipitation particles was recovered by overflow. Next, nickel manganese coprecipitated particles (nickel manganese carbonate) were layered. Specifically, after the recovered liquid was washed with water, nickel manganese coprecipitated particles were immersed in a 2.5 vol% sodium hydroxide aqueous solution, stirred for 15 hours, and then washed again with water. Thereby, nickel manganese hydroxide (Ni _0.25 Mn _0.75 (OH) ₂ ) as a layered compound was obtained. Next, the obtained nickel manganese hydroxide was filtered and dried at 120 ° C. for 10 hours to obtain a nickel manganese precursor powder.

<Production process of lithium nickel manganate active material>
Next, the nickel manganese precursor powder and Li ₂ CO ₃ were weighed so as to have a predetermined molar ratio and mixed by a ball mill. Next, after baking for 8 hours at 1000 ° C. in the air (first baking), after cooling and remixing, baking again in the air for 8 hours at 700 ° C. (second baking) The spinel type positive electrode active material (LiNi _0.5 Mn _1.5 O ₄ ) was obtained.

(Example 2)
A positive electrode active material was produced in the same manner as Example 1 except for the following points.
Coprecipitation liquid (3):
Addition conditions: Added to the reaction vessel intermittently so that the pH was 10.

(Example 3)
A positive electrode active material was produced in the same manner as Example 1 except for the following points.
Coprecipitation liquid (1):
Type: A mixed aqueous solution in which NaI was additionally added to the mixed aqueous solution of Example 1 (nickel manganese mixed aqueous solution) at a concentration of 1.5 mol / l was used.
Coprecipitation additive (3)
Addition conditions: Added to the reaction vessel intermittently so that the pH was 10.

Example 4
A spinel-type positive electrode active material (LiNi _0.48 Mn _1.48 Al _0.04 O ₄ ) in which manganese sites were replaced with nickel and aluminum was obtained in the same manner as Example 1 except for the following points.
Coprecipitation additive (1)
Type: In addition to manganese sulfate as the nickel source and nickel sulfate as the manganese source, a 1.5 mol / l mixed solution in which aluminum nitrate as the aluminum source was further added (the atomic ratio of Ni: Mn: Al is 24:74: 2) was used.

(Comparative Example 1)
A positive electrode active material was produced in the same manner as Example 1 except for the following points.
Coprecipitation liquid (2):
Type: An ammonium sulfate aqueous solution having a concentration of 1.2 mol / l was used.
Coprecipitation additive (3)
Type: A sodium hydroxide aqueous solution having a concentration of 25% by mass was used.
Addition conditions: Added to the reaction vessel intermittently so that the pH was 10.

(Comparative Example 2)
A positive electrode active material was produced in the same manner as in Example 1 except that the first firing temperature in the production process of the lithium nickel manganate active material was 900 ° C.

(Comparative Example 3)
A positive electrode active material was produced in the same manner as Example 1 except for the following points.
The carbonate obtained by coprecipitation was used as a precursor without being layered.
The first firing temperature in the production process of the nickel nickel manganate active material was set to 1000 ° C.

(Comparative Example 4)
A positive electrode active material was produced in the same manner as Example 1 except for the following points.
The carbonate obtained by coprecipitation was used as a precursor without being layered.
The first firing temperature in the production process of the nickel nickel manganate active material was set to 900 ° C.

(Comparative Example 5)
A positive electrode active material was produced in the same manner as Example 1 except for the following points.
Coprecipitation additive (1)
Addition conditions: Continuously added to the reaction vessel at a flow rate of 1 cc / min.
Coprecipitation additive (2)
Addition conditions: Continuously added to the reaction vessel at a flow rate of 0.16 cc / min.
Coprecipitation additive (3)
Type: A sodium hydroxide aqueous solution having a concentration of 25% by mass was used.
Addition conditions: Added to the reaction vessel intermittently so that the pH was 11.

(Evaluation method)
The following evaluation was performed about the precursor particle and positive electrode active material particle of Examples 1-4 and Comparative Examples 1-5 which were produced as mentioned above.

(Particle shape)
The shapes of the precursor particles and the positive electrode active material particles were observed using a field emission scanning electron microscope (FE-SEM).

(Crystal structure)
The crystal structures of the precursor particles and the positive electrode active material particles were identified by X-ray diffraction (XRD) measurement using CuKα as an X-ray source. Among the results, the XRD patterns of the precursor particles (layered compound) of Example 1 and the precursor particles (carbonate) of Comparative Example 3 are shown in FIG.

(Crystal plane orientation)
The plane orientation of the crystal plane was identified as follows.
The crystal plane (polygonal surface) of the primary particles was observed using a transmission electron microscope (TEM), and the plane orientation of the crystal plane was identified from the electron diffraction pattern. In addition, since it is difficult to prepare a sample for identifying all crystal planes with respect to one primary particle, the crystal plane was measured for a plurality of primary particles, and the plane orientation of the crystal plane was specified.

(Average length of precursor primary particles)
Precursor particles are observed using a field emission scanning electron microscope (FE-SEM), and the maximum length Rm of any of the plurality of particles is averaged to determine the average length of the primary particles of the precursor. Asked. Here, the maximum length Rm means the maximum passing length of the primary particles in a range that can be observed in the SEM image (that is, a range that can be observed from any one direction).

(Median diameter of positive electrode active material particles)
The particle diameter of the positive electrode active material particles was measured with a laser diffraction particle size distribution analyzer (manufactured by Shimadzu Corporation, model name: SALD-7100), and the median diameter (D50) was determined.

(Average number of primary particles A)
The average number A of primary particles was determined as follows.
First, using a field emission scanning electron microscope (FE-SEM), the secondary particles of the positive electrode active material can be arbitrarily observed at a magnification (for example, 5000 times if the secondary particle size is about 15 μm). Observation from one direction gave an SEM image of secondary particles of the positive electrode active material. Next, from the SEM image (that is, an observation image in an arbitrary direction), among the primary particles that can be confirmed to be included in one secondary particle, the number a of primary particles having a maximum length Rm of 1 μm or more is determined. I counted. Therefore, even primary particles contained in one secondary particle are primary particles whose maximum length Rm is less than 1 μm and primary particles that cannot be confirmed from SEM images (that is, cannot be observed from any one direction). Primary particles) were excluded from the count. Here, the maximum length Rm means the maximum passing length of the primary particles in the range that can be observed in the SEM image (that is, the range that can be observed from any one direction) as shown in FIG. To do. The above observation and measurement were performed on 10 randomly selected secondary particles to obtain the numbers a ₁ , a ₂ ,..., A ₁₀ . Next, the obtained numbers a ₁ , a ₂ ,..., A ₁₀ were simply averaged (arithmetic average) to obtain the average number A of primary particles.

(Average number of crystal faces B)
The average number B of crystal faces was determined as follows.
First, an SEM image of secondary particles of the positive electrode active material was obtained in the same manner as the above-described “average number of primary particles A”. Next, the number b of flat crystal faces (flat crystal faces of primary particles) included in the surface of one secondary particle was counted from this SEM image (that is, an observation image in an arbitrary direction). In addition, curved surfaces with indefinite crystal faces and fine crystal faces were excluded from the count. Here, the fine crystal plane means a crystal plane included in primary particles having a maximum length Rm of less than 1 μm. The definition of the maximum length Rm is the same as the definition in the above-mentioned “average number of primary particles A”. The above observations and measurements were performed on 10 randomly selected secondary particles, and the number of faces b ₁ , b ₂ ,..., B ₁₀ was obtained. Next, the obtained number of faces b ₁ , b ₂ ,..., B ₁₀ was simply averaged (arithmetic mean) to obtain the average face number B of crystal faces.

(Ratio (B / A))
The ratio (B / A) was determined as follows.
First, as described above, an average number A of primary particles and an average number B of crystal faces were obtained. Next, the ratio (B / A = (average number of crystal faces) / (average number of primary particles)) was determined using the average number A of primary particles and the average number B of crystal faces obtained. .

(Specific surface area)
The specific surface area of the positive electrode active material particles was determined using a BET specific surface area measuring device (manufactured by Nippon Bell, model name: BELSORP-miniII).

(Cycle characteristics)
Using the positive electrode active material particles obtained as described above, a coin-type non-aqueous electrolyte secondary battery (hereinafter referred to as “coin cell”) is manufactured, and the cycle characteristics (discharge capacity retention rate) of the battery are set. evaluated.

First, 90% by mass of the positive electrode active material, 5% by mass of a conductive carbon material having a specific surface area of 60 m ² / g, and 5% by mass of polyvinylidene fluoride were kneaded with an appropriate amount of NMP and dried at 100 ° C. Thus, a positive electrode mixture powder was obtained. Next, this mixture powder was fixed to an aluminum mesh having a diameter of 15 mm by pressing to obtain a positive electrode.

Next, a Li metal foil punched into a disk shape having a predetermined size was prepared as the negative electrode. Next, a microporous film made of polyethylene having a thickness of 25 μm was prepared as a separator. Next, a non-aqueous electrolyte is prepared by dissolving LiPF ₆ as an electrolyte salt to a concentration of 1 mol / kg in a solvent in which ethylene carbonate (EC) and dimethyl carbonate (DMC) are mixed at a mass ratio of 1: 1. Was prepared.

  Next, the produced positive electrode and negative electrode were laminated | stacked through the microporous film, and it was set as the laminated body, the nonaqueous electrolyte solution was accommodated in the exterior cup and the exterior can together with this laminated body, and it crimped via the gasket. As a result, a coin cell of 2016 size (diameter 20 mm, height 1.6 mm) was obtained.

(Evaluation results)
FIG. 9 shows the evaluation results of the cycle characteristics of Examples 1 to 3 and Comparative Examples 1 to 4. 10A to 12F show SEM images of the coprecipitated particles and positive electrode active materials of Examples 1 to 4 and Comparative Examples 1 to 5.

Table 1 shows the evaluation results of the coprecipitated particles of Examples 1 to 4 and Comparative Examples 1 to 5.

Table 2 shows the evaluation results of the positive electrode active material particles of Examples 1 to 4 and Comparative Examples 1 to 5 and coin cells using the positive electrode active material particles.

(Discussion)
The following can be understood from Tables 1 and 2 and FIG.
<Examples 1-4>
Precursor: Since the precursor (layered compound) is produced via carbonate, spherical particles having an average primary particle length of 0.2 μm or less are obtained.
Positive electrode active material particles: The primary particles are polyhedrons having a crystal plane exceeding 8 faces, the ratio (B / A) satisfies the relationship of 2 or more and 20 or less, and the specific surface area is 0.4 m ² / g or less. Become. Further, the median diameter of secondary particles is 10 μm or more and 50 μm or less, the average number A of primary particles is 50 or less, and the average total B of the constituent surfaces of the primary particles is 10 or more and 200 or less.
Cycle characteristics: The capacity retention rate hardly changes even when the number of cycles increases, and is maintained at a high value of 96% or more after 20 cycles.

<Comparative Example 1>
Precursor: Since the precursor particles (layered compound) are not produced via carbonate, the shape of the precursor particles is plate-like, and the average length of the primary particles of the precursor is increased to 2 μm.
Positive electrode active material particles: The primary particles are octahedral and the ratio (B / A) is less than 2.
Cycle characteristics: As the number of cycles increases, the capacity retention rate decreases, and after 20 cycles, it decreases to 93%.

<Comparative example 2>
Precursor: Since the precursor (layered compound) is produced via carbonate, spherical particles having an average primary particle length of 0.2 μm or less are obtained.
Positive electrode active material particles: A positive electrode active material is produced using the above precursor particles, but the specific surface area exceeds 0.4 m ² / g because the first firing temperature is as low as 900 ° C. Further, the average number A of primary particles exceeds 50.
Cycle characteristics: As the number of cycles increases, the capacity retention rate decreases. In particular, the capacity retention rate is remarkably reduced at 13 cycles or more, and is reduced to 80% after 20 cycles.

<Comparative Example 3>
Precursor: Carbonate is used as precursor particles without forming a layered compound.
Positive electrode active material particles: Since the above precursor particles are used, the primary particles have an octahedral shape, a ratio (B / A) of less than 2, and a specific surface area of 0.4 m ² / g. Exceed.
Cycle characteristics: As the number of cycles increases, the capacity retention rate decreases. In particular, the capacity retention rate is remarkably reduced at 12 cycles or more, and is reduced to 73% after 20 cycles.

<Comparative example 4>
Precursor: Carbonate is used as precursor particles without forming a layered compound.
Positive electrode active material particles: Since the above precursor particles are used and the first firing temperature is as low as 900 ° C., the primary particles have a spherical shape (indefinite shape), and the ratio (B / A) is 2 and the specific surface area also exceeds 0.4 m ² / g. Moreover, the average number A of primary particles exceeds 50, and the average number B of crystal faces of the primary particles is less than 10.
Cycle characteristics: As the number of cycles increases, the capacity retention rate decreases remarkably, and after 20 cycles it decreases to 88%.

<Comparative Example 5>
Precursor: Since the precursor particles (layered compound) are not prepared via carbonate, the shape of the precursor particles is indefinite.
Positive electrode active material particles: The primary particles have an octahedral particle shape and a specific surface area of 0.665 m ² / g. In addition, the median diameter of the secondary particles is less than 10 μm.
Cycle characteristics: As the number of cycles increases, the capacity retention rate decreases, and after 20 cycles it decreases to 81%.

(Conclusion)
As described above, the primary particle has a polyhedron shape having a crystal face exceeding 8 faces, the ratio (B / A) is 2 or more and 20 or less, and the specific surface area is 0.4 m ² / g or less. Is preferred.
The median diameter of the secondary particles is preferably 10 μm or more and 50 μm or less.
The average number A of primary particles is preferably 1 or more and 50 or less, and the average number B of crystal faces of the primary particles is preferably 10 or more and 200 or less.

As a method for producing a positive electrode active material satisfying the particle shape, ratio (B / A) and specific surface area of the primary particles described above, precursor particles (layered compounds) are produced via carbonates, and then the precursors are produced. It is preferable to use a method of mixing and baking the particles with a lithium source (lithium carbonate).
As the primary particles of the precursor particles, spherical particles having an average length of 0.01 μm or more and 0.2 μm or less are preferably used.

  As mentioned above, although embodiment of this technique was described concretely, this technique is not limited to the above-mentioned embodiment, Various deformation | transformation based on the technical idea of this technique is possible.

  For example, the configurations, methods, processes, shapes, materials, numerical values, and the like given in the above-described embodiments are merely examples, and different configurations, methods, processes, shapes, materials, numerical values, and the like are used as necessary. Also good.

  The configurations, methods, processes, shapes, materials, numerical values, and the like of the above-described embodiments can be combined with each other without departing from the gist of the present technology.

The present technology can also employ the following configurations.
(1)
Including secondary particles in which primary particles are aggregated,
The primary particles are composite oxide particles having a spinel structure, including lithium (Li) and manganese (Mn),
The primary particle is a polyhedron having a crystal face exceeding eight faces,
Ratio (B / A) (where A: when one secondary particle is observed from one direction, the average number of primary particles having a maximum length of 1 μm or more contained in the secondary particle, B: from one direction When observing one secondary particle, the average number of crystal faces included in the surface of the secondary particle) is 2 or more and 20 or less,
A positive electrode active material having a specific surface area of 0.4 m ² / g or less.
(2)
The positive electrode active material according to (1), wherein the median diameter of the secondary particles is 10 μm or more and 50 μm or less.
(3)
The average number A of the primary particles is 1 or more and 50 or less,
The positive electrode active material according to (1) or (2), wherein the average number B of crystal faces of the primary particles is 10 or more and 200 or less.
(4)
The positive electrode active material according to any one of (1) to (3), wherein the crystal plane exceeding eight faces includes at least one of a {100} plane and a {110} plane.
(5)
The primary particles include chromium (Cr), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), titanium (Ti), aluminum (Al), germanium (Ge), The positive electrode active material according to any one of (1) to (4), further including at least one member selected from the group consisting of gallium (Ga), magnesium (Mg), vanadium (V), and lithium (Li).
(6)
The said composite oxide is a positive electrode active material in any one of (1) to (5) which has the average composition shown to the following formula | equation (1).
Li _{1 + W} (Mn _2-XY A _X B _Y ) O _4-Z (1)
(In the formula, A is at least one selected from the group consisting of chromium (Cr), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), and titanium (Ti)). B represents at least one selected from the group consisting of aluminum (Al), germanium (Ge), gallium (Ga), magnesium (Mg), vanadium (V), and lithium (Li). , Y and Z are values within the ranges of −0.1 ≦ W ≦ 0.1, 0 ≦ X ≦ 0.6, 0 ≦ Y ≦ 0.3, and −0.1 ≦ Z ≦ 0.1. .)
(7)
Containing a positive electrode active material including secondary particles in which primary particles are aggregated;
The primary particles are composite oxide particles having a spinel structure, including lithium (Li) and manganese (Mn),
The primary particle is a polyhedron having a crystal face exceeding eight faces,
Ratio (B / A) (where A: when one secondary particle is observed from one direction, the average number of primary particles having a maximum length of 1 μm or more contained in the secondary particle, B: from one direction When observing one secondary particle, the average sum of crystal planes contained on the surface of the secondary particle is 2 or more and 20 or less,
The positive electrode has a specific surface area of 0.4 m ² / g or less.
(8)
A positive electrode, a negative electrode, and an electrolyte;
The positive electrode contains a positive electrode active material including secondary particles in which primary particles are aggregated,
The primary particles are composite oxide particles having a spinel structure, including lithium (Li) and manganese (Mn),
The primary particle is a polyhedron having a crystal face exceeding eight faces,
Ratio (B / A) (where A: when one secondary particle is observed from one direction, the average number of primary particles having a maximum length of 1 μm or more contained in the secondary particle, B: from one direction When observing one secondary particle, the average sum of crystal planes contained on the surface of the secondary particle is 2 or more and 20 or less,
A battery having a specific surface area of 0.4 m ² / g or less.
(9)
A precursor is prepared by layering a carbonate containing manganese (Mn),
A method for producing a positive electrode active material, comprising producing particles of a composite oxide having a spinel structure containing lithium and manganese by reacting the precursor with a lithium source.
(10)
The average length of the primary particles of the precursor is the method for producing a positive electrode active material according to (9), which is spherical particles having a diameter of 0.01 μm to 0.2 μm.
(11)
The said precursor particle is a manufacturing method of the positive electrode active material as described in (9) or (10) which has a hydroxide containing manganese (Mn) as a main component.
(12)
The positive electrode active material according to any one of (9) to (11), further comprising co-precipitating the carbonate containing manganese from a solution containing a metal salt containing manganese (Mn) and carbonate ions. Production method.
(13)
The solution further includes a metal salt containing a transition metal element other than manganese (Mn),
When coprecipitating the carbonate, manganese and manganese (Mn) from a solution containing a metal salt containing manganese (Mn), a metal salt containing a transition metal element other than manganese (Mn), and carbonate. The method for producing a positive electrode active material according to (12), wherein the carbonate containing a transition metal element other than (Mn) is coprecipitated.
(14)
A battery pack comprising the battery according to (8).
(15)
(8) provided with the battery according to
An electronic device that receives power from the battery.
(16)
A battery according to (8);
A conversion device that receives supply of electric power from the battery and converts it into driving force of the vehicle;
An electric vehicle comprising: a control device that performs information processing related to vehicle control based on information related to the battery.
(17)
(8) provided with the battery according to
A power storage device that supplies electric power to an electronic device connected to the battery.
(18)
A power information control device that transmits and receives signals to and from other devices via a network,
The power storage device according to (17), wherein charge / discharge control of the battery is performed based on information received by the power information control device.
(19)
A power system that receives power from the battery according to (8) or that supplies power to the battery from a power generation device or a power network.

DESCRIPTION OF SYMBOLS 11 Battery can 12, 13 Insulation board 14 Battery cover 15 Safety valve mechanism 15A Disk board 16 Heat sensitive resistance element 17 Gasket 20, 30 Winding electrode body 21, 33 Positive electrode 21A, 33A Positive electrode collector 21B, 33B Positive electrode active material layer 22 , 34 Negative electrode 22A, 34A Negative electrode current collector 22B, 34B Negative electrode active material layer 23, 35 Separator 24 Center pin 25, 31 Positive electrode lead 26, 32 Negative electrode lead 36 Electrolyte layer 37 Protective tape 40 Exterior member 41 Adhesive film

Claims (19)

Including secondary particles in which primary particles are aggregated,
The primary particles are composite oxide particles having a spinel structure, including lithium (Li) and manganese (Mn),
The primary particle is a polyhedron having a crystal face exceeding eight faces,
Ratio (B / A) (where A: when one secondary particle is observed from one direction, the average number of primary particles having a maximum length of 1 μm or more contained in the secondary particle, B: from one direction When observing one secondary particle, the average number of crystal faces included in the surface of the secondary particle) is 2 or more and 20 or less,
A positive electrode active material having a specific surface area of 0.4 m ² / g or less.   The positive electrode active material according to claim 1, wherein the median diameter of the secondary particles is 10 μm or more and 50 μm or less. The average number A of the primary particles is 1 or more and 50 or less,
2. The positive electrode active material according to claim 1, wherein an average number B of crystal faces of the primary particles is 10 or more and 200 or less.   2. The positive electrode active material according to claim 1, wherein the crystal plane exceeding eight faces includes at least one of a {100} plane and a {110} plane.   The primary particles include chromium (Cr), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), titanium (Ti), aluminum (Al), germanium (Ge), The positive electrode active material according to claim 1, further comprising at least one member selected from the group consisting of gallium (Ga), magnesium (Mg), vanadium (V), and lithium (Li). The positive electrode active material according to claim 5, wherein the composite oxide has an average composition represented by the following formula (1).
Li _{1 + W} (Mn _2-XY A _X B _Y ) O _4-Z (1)
(In the formula, A is at least one selected from the group consisting of chromium (Cr), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), and titanium (Ti)). B represents at least one selected from the group consisting of aluminum (Al), germanium (Ge), gallium (Ga), magnesium (Mg), vanadium (V), and lithium (Li). , Y and Z are values within the ranges of −0.1 ≦ W ≦ 0.1, 0 ≦ X ≦ 0.6, 0 ≦ Y ≦ 0.3, and −0.1 ≦ Z ≦ 0.1. .) Containing a positive electrode active material including secondary particles in which primary particles are aggregated;
The primary particles are composite oxide particles having a spinel structure, including lithium (Li) and manganese (Mn),
The primary particle is a polyhedron having a crystal face exceeding eight faces,
Ratio (B / A) (where A: when one secondary particle is observed from one direction, the average number of primary particles having a maximum length of 1 μm or more contained in the secondary particle, B: from one direction When observing one secondary particle, the average sum of crystal planes contained on the surface of the secondary particle is 2 or more and 20 or less,
The positive electrode has a specific surface area of 0.4 m ² / g or less. A positive electrode, a negative electrode, and an electrolyte;
The positive electrode contains a positive electrode active material including secondary particles in which primary particles are aggregated,
The primary particles are composite oxide particles having a spinel structure, including lithium (Li) and manganese (Mn),
The primary particle is a polyhedron having a crystal face exceeding eight faces,
Ratio (B / A) (where A: when one secondary particle is observed from one direction, the average number of primary particles having a maximum length of 1 μm or more contained in the secondary particle, B: from one direction When observing one secondary particle, the average sum of crystal planes contained on the surface of the secondary particle is 2 or more and 20 or less,
A battery having a specific surface area of 0.4 m ² / g or less. A precursor is prepared by layering a carbonate containing manganese (Mn),
A method for producing a positive electrode active material, comprising producing particles of a composite oxide having a spinel structure containing lithium and manganese by reacting the precursor with a lithium source.   The method for producing a positive electrode active material according to claim 9, wherein an average length of primary particles of the precursor is a spherical particle having a diameter of 0.01 μm to 0.2 μm.   The method for producing a positive electrode active material according to claim 9, wherein the precursor particles have a hydroxide containing manganese (Mn) as a main component.   The method for producing a positive electrode active material according to claim 9, further comprising co-precipitating the carbonate containing manganese from a solution containing a metal salt containing manganese (Mn) and carbonate ions. The solution further includes a metal salt containing a transition metal element other than manganese (Mn),
When coprecipitating the carbonate, manganese and manganese (Mn) from a solution containing a metal salt containing manganese (Mn), a metal salt containing a transition metal element other than manganese (Mn), and carbonate. The method for producing a positive electrode active material according to claim 12, wherein the carbonate containing a transition metal element other than (Mn) is coprecipitated.   A battery pack comprising the battery according to claim 8. A battery according to claim 8,
An electronic device that receives power from the battery. A battery according to claim 8;
A conversion device that receives supply of electric power from the battery and converts it into driving force of the vehicle;
An electric vehicle comprising: a control device that performs information processing related to vehicle control based on information related to the battery. A battery according to claim 8,
A power storage device that supplies electric power to an electronic device connected to the battery. A power information control device that transmits and receives signals to and from other devices via a network,
The power storage device according to claim 17, wherein charge / discharge control of the battery is performed based on information received by the power information control device.   The electric power system which receives supply of electric power from the battery of Claim 8, or supplies electric power to the said battery from a generator or an electric power network.