Secondary battery

Abstract

To provide a positive electrode active material which is improved in powder physical properties while improving load resistance such as a rate and output resistance in use as a positive electrode active material used for a lithium ion secondary battery, and is manufactured in a short cycle time at low cost.SOLUTION: The positive electrode active material is formed through a first step in which a compound containing one or more elements selected from magnesium, calcium, zirconium, lanthanum, and barium, a compound containing a halogen and an alkali metal, and a fluoride containing one or more metals selected from nickel, aluminum, manganese, titanium, vanadium, iron, and chromium are each pulverized and then mixed with metal oxide powder to form a first mixture, and a second step in which heating is performed at a temperature higher than or equal to 700 °C and lower than or equal to 950 °C.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] One aspect of the present invention relates to an article, a method, or a manufacturing method. Process, machine, manufacture, or composition of matter One embodiment of the present invention relates to a semiconductor device, a display device, a light-emitting device, a power storage device, a lighting device, or a semiconductor device. In particular, the present invention relates to a secondary battery that can be used in an electronic device or a method for manufacturing the same. The present invention relates to a positive electrode active material, a secondary battery, and an electronic device having the secondary battery.

[0002] In this specification, the term "power storage device" refers to elements and devices in general that have a power storage function. For example, lithium-ion secondary batteries and other storage batteries (also called secondary batteries) This includes lithium ion capacitors and electric double layer capacitors.

[0003] In this specification, the term "electronic device" refers to any device that has a power storage device. Electro-optical devices having a power storage device, and information terminal devices having a power storage device are all electronic devices. [Background technology]

[0004] In recent years, various types of energy storage devices have become available, including lithium-ion secondary batteries, lithium-ion capacitors, and air batteries. The development of lithium-ion batteries, which have high output and high energy density, is particularly active. Secondary batteries are used in mobile phones, smartphones, tablets, or laptops. mobile information terminals, portable music players, digital cameras, medical equipment, next-generation clean energy Hybrid vehicles (HVs), electric vehicles (EVs), plug-in hybrid vehicles Demand for rechargeable electric vehicles (PHVs, etc.) is rapidly expanding along with the development of the semiconductor industry. As a source of energy, it has become an essential part of today's information society.

[0005] The characteristics required for lithium-ion secondary batteries are higher energy density and , improved cycle characteristics, safety in various operating environments, and improved long-term reliability.

[0006] Therefore, we developed a positive electrode with the aim of improving the cycle characteristics and increasing the capacity of lithium-ion secondary batteries. Improvements to the active material have been investigated (Patent Documents 1 and 2). Research into the crystal structure is also being conducted (Non-Patent Documents 1 to 3).

[0007] Non-Patent Document 4 describes the physical properties of metal fluorides.

[0008] X-ray diffraction (XRD) is one of the techniques used to analyze the crystalline structure of positive electrode active materials. ICSD (Inorganic Crystal Streptavidin) introduced in Non-Patent Document 5 Analysis of XRD data using the Structure Database can be done. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-216760 [Patent Document 2] Japanese Patent Application Laid-Open No. 2006-261132 [Non-patent literature]

[0010] [Non-Patent Document 1] Toyoki Okumura et al, “Correlation of lithium ion distribution and X-ray absorption near-edge structure in O3- and O2-lithium cobalt oxides from first-principle calculation”, Journal of Materials Chemistry, 2012, 22, p.17340-17348 [Non-patent document 2] Motohashi, T. et al, “Electronic phase diagram of the layered cobalt oxide system LixCoO2(0.0≦x≦1.0)”, Physical Review B, 80(16);165114 [Non-patent document 3] Zhaohui Chen et al, “Staging Phase Transitions in LixCoO2,” Journal of The Electrochemical Society, 2002, 149(12) A1604-A1609 [Non-patent document 4] WE Counts et al, “Fluoride Model Systems: II, The Binary Systems CaF2-BeF2, MgF2-BeF2, and LiF-MgF2,” Journal of the American Ceramic Society,(1953) 36[1] 12-17. Fig.01471 [Non-patent document 5] Belsky, A. et al., “New developments in the Inorganic Crystal Structure Database (ICSD): accessibility in support of materials research and design”, Acta Cryst., (2002) B58 364-369 Summary of the Invention [Problem to be solved by the invention]

[0011] One aspect of the present invention is a method for producing a lithium ion secondary battery having high capacity and excellent charge / discharge cycle characteristics. It is an object of the present invention to provide a positive electrode active material and a manufacturing method thereof. An object of one embodiment is to provide a method for manufacturing a positive electrode active material with high productivity. One embodiment of the present invention is to improve the efficiency of charge / discharge cycles by using the present invention in a lithium ion secondary battery. Another object of the present invention is to provide a positive electrode active material in which the decrease in the amount of the positive electrode active material is suppressed. Another object of the present invention is to provide a high-capacity secondary battery. Another object of the present invention is to provide a secondary battery having excellent charge-discharge characteristics. In this way, the elution of transition metals such as cobalt is suppressed even when the battery is kept in a high-voltage charged state for a long time. Another object of the present invention is to provide a positive electrode active material having a low temperature and a high resistance to shock. An object of the present invention is to provide a secondary battery with high performance and reliability.

[0012] Another embodiment of the present invention is a novel substance, active material particles, a power storage device, or a manufacturing method thereof. One of our goals is to provide a method for

[0013] The description of these problems does not preclude the existence of other problems. It is not necessary for one embodiment to solve all of these problems. It is possible to extract other problems from the claims. [Means for solving the problem]

[0014] One aspect of the present invention is a compound having an element X and a compound having a halogen and an alkali metal. The compound and the metal fluoride are each finely pulverized and then mixed with the metal oxide powder to form a first The first step is to prepare a mixture, and the second step is to heat the mixture at a temperature of 700°C or more and 950°C or less. and the element X is magnesium, calcium, zirconium, lanthanum, and and barium, and the metal fluoride is one or more selected from nickel, aluminum, manganese, The metal oxide has one or more selected from the group consisting of gallium, titanium, vanadium, iron, and chromium. Method for producing a positive electrode active material containing one or more selected from cobalt, manganese, nickel, and iron It is the law.

[0015] In the above configuration, the average particle diameter of the obtained positive electrode active material is 1 μm or more and 100 μm or less. In the above structure, the metal oxide is preferably represented by the space group R-3m. In the above structure, the metal oxide preferably has a structure in which lithium cobalt oxide is used. It is preferable that the compound is ammonium.

[0016] Alternatively, one embodiment of the present invention is a method for manufacturing a fluoride-containing electrolytic solution containing magnesium fluoride, lithium fluoride, and aluminum fluoride. and ammonium hydroxide are each finely pulverized and then mixed with a metal oxide powder to form a first mixture. and a second step of heating at a temperature of 700°C or higher and 950°C or lower. The metal oxide has a metal M, and the metal M is selected from the group consisting of cobalt, manganese, nickel, and iron. The present invention provides a method for producing a positive electrode active material selected from the above.

[0017] In the above-mentioned configuration, the magnesium fluoride contained in the first mixture The number of atoms of M is 0.005 to 0.05 times the number of atoms of the metal M contained in the metal oxide. In the above-mentioned configuration, it is preferable that the first mixture contains aluminum fluoride. The number of aluminum atoms in aluminum is the same as the number of metal M atoms in metal oxides. The total number of aluminum atoms in aluminum is 0.0005 to 0.02 times the total number of aluminum atoms in aluminum. In the above configuration, it is preferable that the average particle diameter of the obtained positive electrode active material is 1 μm or more. In the above structure, the metal oxide preferably has a particle size of at most 100 μm. In the above structure, the metal oxide preferably has a structure represented by R-3m. Lithium cobalt oxide is preferred.

[0018] Alternatively, one embodiment of the present invention is a method for manufacturing a nickel compound comprising magnesium fluoride, lithium fluoride, and a nickel compound. The material and aluminum fluoride were each finely pulverized and then mixed with metal oxide powder to form a The first step is to prepare a mixture of 1, and the second step is to heat the mixture at a temperature of 700°C or higher and 950°C or lower. 2, wherein the metal oxide comprises a metal M, and the metal M is selected from the group consisting of cobalt, manganese, nickel, and the like. The present invention provides a method for producing a positive electrode active material that is at least one selected from nickel and iron.

[0019] In the above structure, the nickel compound is preferably nickel hydroxide. In the above-mentioned configuration, in the first mixture, magnesium fluoride has magnesium The number of atoms of the metal M contained in the metal oxide is 0.005 times or more and 0.05 times or less. In the above-mentioned configuration, it is preferable that the first mixture contains aluminum fluoride. The number of aluminum atoms in the metal oxide is the number of metal M atoms in the aluminum fluoride. The number of aluminum atoms contained in the aluminum is 0.0005 to 0.02 times the sum of the number of aluminum atoms contained in the aluminum. In the above configuration, it is preferable that the average particle size of the obtained positive electrode active material is 1 μm or more and 1 μm or less. In the above structure, the metal oxide preferably has a particle size of 00 μm or less. In the above structure, the metal oxide preferably has a structure represented by the formula 3m. Lithium phosphate is preferred. [Effects of the Invention]

[0020] According to one aspect of the present invention, a lithium ion secondary battery having high capacity and excellent charge-discharge cycle characteristics is provided. The present invention provides a positive electrode active material for a battery and a method for producing the same. It is possible to provide a method for producing an active material. Therefore, it is possible to provide a positive electrode active material that suppresses the decrease in capacity during charge / discharge cycles. In addition, a high-capacity secondary battery can be provided. In addition, a secondary battery with excellent charge / discharge characteristics can be provided. Furthermore, even if the charged state at high voltage is maintained for a long time, cobalt It is possible to provide a positive electrode active material in which the elution of transition metals such as zinc is suppressed. In addition, the present invention provides a highly reliable secondary battery. Apparatuses or methods for making them may be provided. [Brief explanation of the drawings]

[0021] [Figure 1] Figure 1A and Figure 1B are diagrams illustrating a method for producing a substance. [Figure 2] 2A and 2B are diagrams illustrating a method for producing a positive electrode active material. [Figure 3] FIG. 3 is a diagram illustrating a method for producing a positive electrode active material. [Figure 4] FIG. 4 is a diagram illustrating a method for producing a positive electrode active material. [Figure 5]Fig. 5A is a diagram illustrating a coin-type secondary battery, Fig. 5B is a diagram illustrating a coin-type secondary battery, and Fig. 5C is a diagram illustrating charging of the secondary battery. [Figure 6] Fig. 6A is a diagram illustrating a cylindrical secondary battery. Fig. 6B is a diagram illustrating a cylindrical secondary battery. Fig. 6C is a diagram illustrating a cylindrical secondary battery. Fig. 6D is a diagram illustrating a cylindrical secondary battery. [Figure 7] Fig. 7A is a diagram illustrating an example of a secondary battery, and Fig. 7B is a diagram illustrating an example of a secondary battery. [Figure 8] Fig. 8A is a diagram illustrating an example of a secondary battery. Fig. 8B is a diagram illustrating an example of a secondary battery. Fig. 8C is a diagram illustrating an example of a secondary battery. Fig. 8D is a diagram illustrating an example of a secondary battery. [Figure 9] 9A and 9B are diagrams illustrating an example of a secondary battery. [Figure 10] FIG. 10 is a diagram illustrating an example of a secondary battery. [Figure 11] Figure 11A is a diagram illustrating a laminated secondary battery, Figure 11B is a diagram illustrating a laminated secondary battery, and Figure 11C is a diagram illustrating a laminated secondary battery. [Figure 12] Fig. 12A is a diagram illustrating a laminated secondary battery, and Fig. 12B is a diagram illustrating a laminated secondary battery. [Figure 13] FIG. 13 is a diagram showing the appearance of a secondary battery. [Figure 14] FIG. 14 is a diagram showing the appearance of a secondary battery. [Figure 15] Figure 15A is a diagram for explaining a method for manufacturing a secondary battery, Figure 15B is a diagram for explaining a method for manufacturing a secondary battery, and Figure 15C is a diagram for explaining a method for manufacturing a secondary battery. [Figure 16]Fig. 16A is a diagram illustrating a bendable secondary battery. Fig. 16B is a diagram illustrating a bendable secondary battery. Fig. 16C is a diagram illustrating a bendable secondary battery. Fig. 16D is a diagram illustrating a bendable secondary battery. Fig. 16E is a diagram illustrating a bendable secondary battery. [Figure 17] Figure 17A is a diagram illustrating a bendable secondary battery, and Figure 17B is a diagram illustrating a bendable secondary battery. [Figure 18] FIG. 18A is a diagram illustrating an example of an electronic device. FIG. 18B is a diagram illustrating an example of an electronic device. FIG. 18C is a diagram illustrating an example of a secondary battery. FIG. 18D is a diagram illustrating an example of an electronic device. FIG. 18E is a diagram illustrating an example of a secondary battery. FIG. 18F is a diagram illustrating an example of an electronic device. FIG. 18G is a diagram illustrating an example of an electronic device. FIG. 18H is a diagram illustrating an example of an electronic device. [Figure 19] Fig. 19A is a diagram illustrating an example of an electronic device, Fig. 19B is a diagram illustrating an example of an electronic device, and Fig. 19C is a diagram illustrating an example of an electronic device. [Figure 20] FIG. 20 is a diagram illustrating an example of an electronic device. [Figure 21] Fig. 21A is a diagram illustrating an example of a vehicle, Fig. 21B is a diagram illustrating an example of a vehicle, and Fig. 21C is a diagram illustrating an example of a vehicle. [Figure 22] Fig. 22A is a diagram illustrating an example of an electronic device, Fig. 22B is a diagram illustrating an example of an electronic device, and Fig. 22C is a diagram illustrating an example of an electronic device. [Figure 23] FIG. 23 shows a DSC. [Figure 24] FIG. 24 shows a DSC. [Figure 25] FIG. 25 shows a DSC. [Figure 26] 26A and 26B are graphs showing the cycle characteristics of a secondary battery. [Figure 27]27A and 27B are graphs showing the cycle characteristics of a secondary battery. DETAILED DESCRIPTION OF THE INVENTION

[0022] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The present invention is not limited to the following description, and it is understood by those skilled in the art that various modifications may be made to the modes and details thereof. The present invention will be easily understood by reading the following description of the embodiments. It is not something that is done.

[0023] In this specification, crystal planes and directions are expressed in Miller indices. In crystallography, numbers are usually marked with a superscript bar, but in this specification and other documents, due to limitations on the notation used in the application, numbers are marked with a superscript bar. Instead of putting a bar above the letter, a number may be expressed by putting a - (minus sign) before it. Also, individual orientations that indicate directions within a crystal are [ ], and collective orientations that indicate all equivalent directions are The symbols are < >, individual crystal faces are ( ), and collective faces with equivalent symmetry are {}. Each one expresses something.

[0024] In this specification, segregation refers to a phenomenon in which a solid consisting of multiple elements (e.g., A, B, C) This refers to the phenomenon in which a certain element (e.g., B) is distributed spatially non-uniformly.

[0025] In this specification, the surface layer of particles of active material or the like refers to the region from the surface to about 10 nm. The surface caused by cracks or fractures can also be called the surface. , called the inside.

[0026] In the present specification and the like, the layered rock salt type crystals of the composite oxide containing lithium and a transition metal The structure is a rock salt type ion arrangement in which cations and anions are arranged alternately, and The lithium atoms are regularly arranged to form a two-dimensional plane, allowing two-dimensional diffusion of lithium. It is possible for defects such as cation or anion deficiencies to exist. Strictly speaking, the layered rock salt crystal structure is a case where the lattice of the rock salt crystal is distorted. There is.

[0027] In this specification and the like, the rock salt type crystal structure refers to a structure in which cations and anions are arranged alternately. It is possible for there to be a deficiency of cations or anions.

[0028] In the present specification and the like, the pseudospinel type of the composite oxide containing lithium and a transition metal The crystal structure of this is in the space group R-3m, and is not a spinel-type crystal structure, but it is a cobalt-based Ions such as magnesium ions occupy the oxygen hexacoordinated positions, and the arrangement of cations is similar to that of spinel. It refers to a crystalline structure with symmetry. The pseudospinel type crystalline structure is characterized by the absence of light elements such as lithium. The atoms may occupy the oxygen tetracoordinate positions, and in this case the ionic arrangement is similar to that of the spinel type. It has symmetry.

[0029] The pseudospinel crystal structure has random Li between layers, but the CdCl2 type It can be said that this CdCl2-type similar crystal structure is The crystal structure is shown in Fig. 1 when lithium nickel oxide is charged to a charge depth of 0.94 (Li 0.06 Ni O2), but pure lithium cobaltate or cobalt-rich layered It is known that rock salt type positive electrode active materials do not usually have this crystal structure.

[0030] Layered rock salt crystals and the anions of rock salt crystals are in a cubic close-packed structure (face-centered cubic lattice structure) ) It is assumed that the anions in pseudospinel crystals also have a cubic close-packed structure. When they contact, there exists a crystal plane where the orientation of the cubic close-packed structure formed by the anions is aligned. However, the space group of layered rock salt crystals and pseudospinel crystals is R-3m, and The space groups of the rock salt crystals are Fm-3m (the common rock salt crystal space group) and Fd-3m (the simplest Since the space group is different from that of rock salt crystals, which have a perfect symmetry, the crystal plane must be The Lahr index is different between layered rock salt crystals and pseudospinel crystals and between rock salt crystals. In the layered rock salt crystal, pseudospinel crystal, and rock salt crystal, When the orientation of the cubic close-packed structure is aligned, the crystal orientation is roughly the same. There is.

[0031] The crystal orientation of the two regions roughly coincides with each other, as can be seen from TEM (transmission electron microscope) images and STE M (scanning transmission electron microscope) image, HAADF-STEM (high angle annular dark field scanning transmission electron microscope) image This should be judged from images such as annular bright-field scanning transmission electron microscope (ABF-STEM) images. X-ray diffraction (XRD), electron diffraction, neutron diffraction, etc. can also be used as a basis for judgment. In TEM images, the arrangement of cations and anions is observed as repeated bright and dark lines. When the orientation of the cubic close-packed structure in the layered rock salt crystal and the rock salt crystal is aligned, the crystal The angle between the repeated bright and dark lines is 5 degrees or less, preferably 2.5 degrees or less. In addition, light elements such as oxygen and fluorine can be clearly observed in TEM images. In some cases, it may not be possible to determine the alignment of the metal elements. do.

[0032] In this specification, the theoretical capacity of the positive electrode active material is the capacity of the positive electrode active material that can be inserted and removed. The theoretical capacity of LiCoO2 is 27 4mAh / g, the theoretical capacity of LiNiO2 is 274mAh / g, the theoretical capacity of LiMn2O4 is 148mAh / g.

[0033] In this specification, the depth of charge when all intercalable and detachable lithium is intercalated is The depth of charge when all the intercalable lithium in the positive electrode active material is deintercalated is 0, and the depth of charge when all the intercalable lithium in the positive electrode active material is deintercalated is 1. Let's assume that this is the case.

[0034] In this specification, charging refers to transferring lithium ions from the positive electrode to the negative electrode in the battery. The positive electrode active material moves electrons from the positive electrode to the negative electrode in an external circuit. In this case, the process of releasing lithium ions is called charging. Also, when the charge depth is 0.7 or more, Positive electrode active materials with a voltage of 0.9 or less are sometimes referred to as positive electrode active materials charged at a high voltage.

[0035] Similarly, discharging involves transferring lithium ions from the negative electrode to the positive electrode within the battery and discharging them into the external circuit. The positive electrode active material is lithium. The insertion of ions is called discharging. The positive electrode active material is fully discharged from a high voltage charged state to 90% or more of its charge capacity. This refers to the positive electrode active material that has been discharged in minutes.

[0036] In this specification, a non-equilibrium phase change refers to a phenomenon that causes a non-linear change in a physical quantity. For example, the capacitance (Q) can be obtained by differentiating it with respect to the voltage (V) (dQ / dV). A non-equilibrium phase change occurs before and after the peak in the dQ / dV curve, and the crystal structure changes significantly. It is believed that this is the case.

[0037] The secondary battery has, for example, a positive electrode and a negative electrode. The positive electrode active material is, for example, a material that undergoes a reaction that contributes to the charge / discharge capacity. The active material may partially contain a substance that does not contribute to the charge / discharge capacity.

[0038] In this specification and the like, the positive electrode active material of one embodiment of the present invention is a positive electrode material or a material for a secondary battery. In this specification and the like, the positive electrode active material of one embodiment of the present invention may be referred to as a positive electrode material. The substance preferably has a compound. The electrode active material preferably has a composition. The positive electrode active material preferably has a composite.

[0039] The discharge rate is the relative ratio of the discharge current to the battery capacity, and is expressed in units of C. For a battery with a rated capacity of X (Ah), the current equivalent to 1C is X (A). When a battery is discharged at a current of X / 5(A), it is said to be discharged at 2C, and when a battery is discharged at a current of X / 5(A), it is said to be discharged at 2C. When the battery was charged, it was discharged at 0.2C. The charging rate was also the same, 2X(A). If it is charged at a current of X / 5(A), it is said to be charged at 2C. In this case, it was charged at 0.2C.

[0040] Constant current charging refers to a method of charging at a constant charge rate. For example, this refers to a method in which, once the upper limit voltage is reached during charging, the voltage is kept constant and charging is continued. Constant current discharge refers to a method of discharging at a constant discharge rate, for example.

[0041] (Embodiment 1) In this embodiment, a positive electrode active material of one embodiment of the present invention and a manufacturing method thereof will be described.

[0042] The positive electrode active material of one embodiment of the present invention comprises a metal A, a transition metal Mt, an element X, a metal M(2), and The positive electrode active material of one embodiment of the present invention may contain a metal M(1).

[0043] Metal A is an alkali metal. Alternatively, metal A may be an alkaline earth metal. stomach.

[0044] The transition metal Mt may be, for example, one or more of cobalt, manganese, nickel, and iron. preferable.

[0045] Element X is, for example, magnesium, calcium, zirconium, lanthanum and barium. One or more of the following may be selected:

[0046] The positive electrode active material of one embodiment of the present invention contains the element X, For example, in secondary batteries using positive electrode active materials, the structure of the positive electrode active material is stable even at high charging voltages. By increasing the charging voltage, the discharge capacity and energy density can be improved. In addition, the increased stability of the structure improves cycle characteristics, etc. It can be done.

[0047] Metal M(2) is, for example, nickel, aluminum, manganese, titanium, vanadium, iron and chromium, in particular one or more of nickel and aluminum. The metal M(1) is preferably nickel, and more preferably aluminum. one selected from nickel, aluminum, manganese, titanium, vanadium, iron and chromium It is preferable that the metal is the above and different from the metal M(2).

[0048] The transition metal Mt is preferably a metal different from the metal M(2). More preferably, metal M(1) and metal M(2) are different metals.

[0049] The positive electrode active material of one embodiment of the present invention contains the metal M(2) in addition to the element X, In a secondary battery using the positive electrode active material of one embodiment, for example, safety may be improved. In addition, the structural stability of the positive electrode active material can be further improved at high charging voltages. In some cases, the charging voltage can be further increased.

[0050] The positive electrode active material of one embodiment of the present invention contains a metal M(1) in addition to the element X and the metal M(2). By doing so, a secondary battery using the positive electrode active material of one embodiment of the present invention can achieve, for example, high charging. In some cases, the stability of the structure of the positive electrode active material can be further improved under high voltage. In addition, the discharge capacity may further increase.

[0051] <Method 1 for producing positive electrode active material> A method for producing a positive electrode active material according to one embodiment of the present invention will be described below with reference to FIGS. 1A and 1B. I will explain.

[0052] In the production flow shown in FIG. 1A, a metal oxide (hereinafter, Metal oxide 95) and several substances (hereinafter referred to as substances 91, 92, 93, and 94) ) are mixed and annealed (step S34), to obtain the positive electrode active material 100 (step Here, four substances are used as an example of multiple substances, but multiple substances can also be three or less. For example, the plurality of substances may be three substances 91, 92, and 94. Good too.

[0053] In the manufacturing flow shown in FIG. 1B, materials 91 to 94 are prepared, and in step S12, The mixture 902 is mixed and crushed (step S14). The metal oxide 95 is mixed and annealed (step 34), to obtain the positive electrode active material 100 (step Step S36).

[0054] By crushing the materials 91 to 94 in advance, the annealing process of step S34 can be performed. In this process, the substances 91 to 94 may easily adhere to the surface of the metal oxide 95 . Furthermore, the contact area between the metal oxide 95 and the substances 91 to 94 may increase. When it is easy to add one or more elements contained in the substances 91 to 94 to the metal oxide 95, There is.

[0055] In FIG. 1B, a solvent is prepared together with the substances 91 to 94, and the substances are mixed by a wet method. However, if mixing is performed by a dry method, it is not necessary to prepare a solvent.

[0056] The metal oxide 95 is preferably in the form of particles.

[0057] Alternatively, the metal oxide 95 may be formed by chemical vapor deposition (CVD). The thin film may be formed by a deposition method, a sputtering method, a vapor deposition method, or the like. For example, the substrate is formed on a material that can be used for a current collector, as described later. Various forms can be used, such as a foil of a material, a glass substrate, a resin substrate, etc.

[0058] As the metal oxide 95, for example, an oxide having a layered rock salt type crystal structure can be used. Alternatively, for example, an oxide having a spinel-type crystal structure can be used. Alternatively, for example, a phosphate compound, a silicate compound, etc. may be used as the metal oxide 95. .

[0059] When the metal oxide 95 has a layered rock salt type crystal structure, the transition metal Mt For example, cobalt, manganese, nickel, aluminum, etc. may be used. Examples of materials containing a transition metal Mt include lithium cobalt oxide, lithium manganese oxide, Lithium nickel oxide, lithium cobalt oxide in which some of the cobalt is replaced with manganese, Lithium cobalt oxide, in which some of the cobalt is replaced by nickel, or nickel-manganese-cobalt oxide Lithium valite is an example.

[0060] For example, an oxide having a structure represented by the space group R-3m may be used as the metal oxide 95. That's fine.

[0061] When the metal oxide 95 is an oxide having a spinel-type crystal structure, the transition metal Mt For example, manganese, nickel, etc. may be used.

[0062] Some of the elements contained in the materials 91 to 94 are converted into metals by the above-mentioned mixing and annealing. It is preferable that the oxide 95 is doped in the surface and near-surface regions or in the interior. By the above-mentioned mixing and annealing, some of the elements contained in the metal oxide 95 are converted into the substance 91. It may be substituted for some of the elements contained in the ultimate substance 94.

[0063] By adding some of the elements contained in the substances 91 to 94 to the metal oxide 95, In a secondary battery using the positive electrode active material of one embodiment of the present invention, for example, the capacity can be improved, and energy It is possible to achieve improved density, improved cycle characteristics, improved reliability, improved safety, etc. This can be done.

[0064] As the substance 91, a halogen compound having a metal A can be used.

[0065] When lithium is used as the metal A, the substance 91 may be, for example, lithium fluoride, salt, or the like. In particular, lithium fluoride is used in the annealing step described later. It is preferable because it melts easily. When sodium is used as metal A, For example, sodium fluoride, sodium chloride, etc. can be used. When sodium is used, for example, potassium fluoride can be used as the substance 91. When calcium is used as metal A, for example, calcium chloride is used as substance 91. , etc. can be used.

[0066] Substance 92 is a compound having element X.

[0067] When magnesium is used as element X, the substance 92 may be, for example, magnesium fluoride. magnesium, magnesium oxide, magnesium hydroxide, magnesium carbonate, magnesium chloride, etc. can be used.

[0068] A mixture of the compound having the element X and the halogen compound having the metal A is By annealing, a eutectic reaction occurs, and the temperature is lower than the melting point of the compound containing element X. At this temperature, melting can occur in at least some regions of the mixture.

[0069] If element X is an element that does not contribute to the charge / discharge reaction of the positive electrode active material, the amount of element X added can be increased. If the amount is too small, there is a concern that the resulting discharge capacity may be significantly reduced. By using the manufacturing method, in the metal oxide 95, the amount of element X on the surface and near the surface can be The concentration of element X in metal oxide 95 can be made higher than the concentration in the interior. By creating a concentration gradient of , and increasing the concentration at the surface and near the surface, Even if the amount of element X added to the entire positive electrode active material is small, there are cases where an efficient effect can be obtained. do.

[0070] For example, the original in the first region at a distance of 20 nm or more and 200 nm or less from the surface The ratio of the number of atoms of element X (Ax1) to the number of atoms of transition metal Mt (Am1) is {(Ax1) / (A m1)} is the element X in the second region at a distance of 1 μm or more and 3 μm or less from the surface. The ratio of the number of atoms of the transition metal Mt (Ax2) to the number of atoms of the transition metal Mt (Am2) is {(Ax2) / (Am2 )} higher.

[0071] The materials 91 and 92 may undergo a eutectic reaction by mixing and annealing. It is preferable that the eutectic point is lowered. Alternatively, it is preferable that the eutectic reaction is prevented from occurring. It is preferable that the eutectic point is lowered. When describing the eutectic reaction of the above, the description should be expressed as eutectic point depression, eutectic reaction, eutectic point depression It may also be applied to.

[0072] When materials 91 and 92 are mixed and annealed, a eutectic is formed between materials 91 and 92. The reaction occurs such that the melting point of substance 91 is lower than the melting point of substance 92. The melting of the mixture of substances 91 and 92 occurs, and one or more of the elements contained in substances 91 and 92 becomes gold. It is easily added to metal oxide 95.

[0073] Substance 93 is a compound containing metal M(1). Substance 94 is a compound containing metal M(2). Substances 93 and 94 are used in the preparation of the positive electrode active material of one embodiment of the present invention. It is preferred that it serves as a gene source.

[0074] A concentration gradient of metal M(2) is generated in the metal oxide 95, and the metal M(2) is By increasing the concentration of the metal M(2) in the positive electrode active material, the amount of the metal M(2) added to the positive electrode active material can be increased. At the very least, it may be possible to achieve efficient results.

[0075] For example, in the first region at a distance of 20 nm or more and 200 nm or less from the surface, The ratio of the number of atoms of the group M(2) (Amb1) to the number of atoms of the transition metal Mt (Am1) {(Amb 1) / (Am1)} is the distance from the surface to the second region of 1 μm or more and 3 μm or less. The ratio of the number of atoms of element X (Amb2) to the number of atoms of transition metal Mt (Am2) {(Amb 2) / (Am2)}.

[0076] One or both of substances 93 and 94 significantly promote the eutectic reaction between substances 91 and 92. If this occurs, annealing can be divided into two steps as shown in Figures 2A and 2B. More specifically, a material other than the material that inhibits the eutectic reaction is mixed and annealed ( In step S34, one or more elements contained in at least one of the substance 91 and the substance 92 are converted into a metal oxide. After adding the compound 95, a substance that inhibits the eutectic reaction is added and mixed, and annealing is performed (S A positive electrode active material 100 is obtained (step S36).

[0077] In FIG. 2A, a material 91, a material 92, and a metal oxide 95 are mixed and annealed. (Step S34), the material 93, the material 94, and the annealed mixture are mixed and annealed. Then, the cathode active material 100 is obtained (step S36). In this method, a material 91, a material 92, a material 93, and a metal oxide 95 are mixed and annealed. (Step S34), the material 94 and the annealed mixture are mixed and annealed ( Step S55), and the positive electrode active material 100 is obtained (Step S36).

[0078] For example, if the eutectic reaction is significantly inhibited by the substance 94, the process of FIG. 2A or FIG. 2B may be repeated. In addition, for example, both the substance 93 and the substance 94 significantly inhibit the eutectic reaction. In this case, the process shown in FIG. 2A can be used.

[0079] Annealing twice reduces productivity and increases costs, so we performed the following process as shown in Figure 1A. Therefore, it is preferable to perform the annealing step only once. It is preferable to minimize the inhibition of the eutectic reaction between the substance 91 and the substance 92. More specifically, for example, The materials 93 and 94 are heated at a temperature lower than the temperature at which the eutectic reaction between the materials 91 and 92 occurs. For example, it is preferable that the stability is high at a temperature lower than the temperature at which the eutectic reaction occurs. It is preferable that the reactivity with element X is low at the temperature.

[0080] On the other hand, if the stability of the materials 93 and 94 is too high, the metal oxide may be easily removed during the annealing process. Therefore, the melting points of the substances 93 and 94 are It is preferable that the temperature is not too high than the annealing temperature. For example, If the melting point is higher than the temperature of the annealing step, the difference between the temperature of the annealing step and the melting point is not preferable. or 500°C or less, more preferably 400°C or less, and even more preferably 300°C or less. In addition to substances 91 and 92, either or both of substances 93 and 94 are present. , a eutectic reaction may occur.

[0081] For example, DSC (Differential Scanning Calorimetry) is used to measure eutectic reactions. It can be evaluated using scanning calorimetry.

[0082] <dsc> In DSC, the measurement temperature is scanned and the change in the amount of heat is observed. It occurs due to endothermic reactions such as solution or exothermic reactions such as crystallization.

[0083] When a eutectic reaction occurs between materials 91 and 92, the reaction temperature and its vicinity For example, a change in heat quantity is observed, which indicates an endothermic reaction.

[0084] Below, we will use magnesium as the element X and aluminum as the metal M(2). Examples of substances 91, 92, and 94 and the results of their DSC evaluation are shown in Figures 23 and 24. and 25. The horizontal axis of Fig. 23, Fig. 24 and Fig. 25 represents temperature (Temperature e), and the vertical axis indicates heat flow.

[0085] Figure 23 shows an example of DSC of a mixture of substances 91 and 92. Lithium fluoride is used as the material 91, and magnesium fluoride is used as the material 92.

[0086] FIG. 24 shows an example of a DSC of a mixture of substances 91, 92, and 94. So, substance 91 is lithium fluoride, substance 92 is magnesium fluoride, and substance 94 is Aluminum hydroxide is used.

[0087] FIG. 25 shows an example of a DSC of a mixture of substances 91, 92, and 94. So, substance 91 is lithium fluoride, substance 92 is magnesium fluoride, and substance 94 is Aluminum fluoride is used.

[0088] Table 1 shows substances 91, 92 and 94 corresponding to Figs. 23, 24 and 25. Shows.

[0089] [Table 1]

[0090] First, from Figure 23, a peak suggesting an endothermic reaction was observed at approximately 735°C. The melting point of lithium is 848°C, and that of magnesium fluoride is 1263°C. The peak observed at 5°C is thought to suggest a decrease in the melting point of lithium fluoride due to the eutectic reaction. can be obtained.

[0091] Next, from Figure 24, a slight peak suggesting an endothermic reaction was observed at approximately 727°C. However, the peak is significantly smaller than the peak at approximately 735°C observed in Figure 23. In other words, the energy change at that temperature is small. The addition of ammonium inhibits the eutectic reaction between lithium fluoride and magnesium fluoride. On the other hand, a peak suggesting an exothermic reaction was observed at approximately 490°C, suggesting that fluorine The magnesium in magnesium chloride is the aluminum in aluminum hydroxide. Therefore, the presence of aluminum hydroxide is thought to be responsible for the There is a shortage of magnesium fluoride to react eutectic with lithium, and lithium fluoride and magnesium fluoride It is thought that the eutectic reaction with the aluminum is inhibited.

[0092] Next, in Figure 25, a peak suggesting an endothermic reaction was observed at approximately 752°C. In comparison, no significant decrease in peak intensity was observed. has little effect on the eutectic reaction between lithium fluoride and magnesium fluoride, and is therefore preferred as a material 94. It turns out to be appropriate.

[0093] The reason why aluminum fluoride exhibits the characteristics shown in Figure 25 is that, for example, is a eutectic reaction between substance 91 and substance 92, for example, lithium fluoride and magnesium fluoride. It is highly stable at temperatures lower than the temperature at which the eutectic reaction of It is thought that this is because it is difficult for the reaction to occur with the magnesium contained in the solution.

[0094] The scanning rate of the measurement temperature in the DSC shown in Figures 23, 24, and 25 was 20°C / min. n.

[0095] 23, 24, and 25 show the results of the method for preparing the positive electrode active material according to one embodiment of the present invention. In this method, compounds containing metal M(2) include halogen compounds containing metal A and elements A fluoride having high stability at temperatures lower than the temperature at which the eutectic reaction of the compound having X occurs It is preferred to use aluminum.

[0096] <Method 2 for producing positive electrode active material> An example of a method for manufacturing a positive electrode active material of one embodiment of the present invention will be described below with reference to FIGS. .

[0097] <Step S11> First, the materials for the mixture 902 are prepared.

[0098] When a compound containing fluorine is used as the substance 91, for example, lithium fluoride, Among them, it is preferable to use lithium fluoride. It's nice.

[0099] When a compound containing magnesium is used as the substance 92, for example, magnesium fluoride is used. Magnesium, magnesium oxide, magnesium hydroxide, magnesium carbonate, etc. can be used. As the lithium source, for example, lithium fluoride or lithium carbonate can be used.

[0100] In this embodiment, lithium fluoride (LiF) is prepared as the substance 91, and fluorine is prepared as the substance 92. Magnesium fluoride MgF2 is prepared (step S11 in FIG. 3).

[0101] Lithium fluoride (LiF) and magnesium fluoride (MgF2) have a ratio of LiF:MgF2=65:3 Mixing at a molar ratio of about 5 results in the greatest effect of lowering the melting point (Non-Patent Document 4). However, if the amount of lithium fluoride is too high, there is a concern that the lithium content will be too high, which could lead to deterioration of cycle characteristics. Therefore, the molar ratio of lithium fluoride LiF to magnesium fluoride MgF2 is L Preferably, LiF:MgF2=x:1 (0≦x≦1.9), and LiF:MgF2= x:1 (0.1≦x≦0.5) is more preferable, and LiF:MgF2=x:1 (x=0.3 3) is more preferable.

[0102] If the subsequent mixing and grinding steps are to be carried out wet, a solvent is prepared. ketones such as acetone, alcohols such as ethanol and isopropanol, ethers, di- Xanthan Gum, acetonitrile, N-methyl-2-pyrrolidone (NMP), etc. can be used. It is more preferable to use an aprotic solvent that is less likely to react with lithium. In this embodiment, acetone is used (see step S11 in FIG. 3).

[0103] <Step S12> Next, the materials of the mixture 902 are mixed and crushed (step S12 in FIG. 3). This can be done by either dry or wet grinding, but the wet grinding method allows for smaller grinding. For mixing, a ball mill, a bead mill, or the like can be used. When using a zirconia ball as the media, it is preferable to use a zirconia ball as the media. By thoroughly performing the mixing and grinding process, a finely pulverized mixture 902 can be obtained in the subsequent process. It is possible.

[0104] The mixing means is preferably a blender, a mixer, or a ball mill.

[0105] <Steps S13 and S14> The mixed and crushed materials are collected (step S13 in FIG. 3) to obtain a mixture 902 ( Step S14 in Figure 3).

[0106] The mixture 902 has, for example, an average particle size (D50) of 600 nm or more and 20 μm or less. The particle size is preferably 1 μm or more and 10 μm or less, and more preferably 1 μm or more and 10 μm or less. If the mixture 902 is made of the metal oxide 95, when it is mixed with the metal oxide 95 in a later step, The mixture 902 can be easily adhered uniformly to the surface of the particles. If the substance 902 is uniformly attached, the surface layer of the metal oxide 95 particles is completely covered with the substance 902 after heating. This is preferred because it allows for easy distribution of halogen and magnesium.

[0107] <Steps S15, S16, and S17> Furthermore, a substance 93 is prepared for mixing in step S31. Nickel hydroxide is mixed with acetone and crushed (slurry). The nickel hydroxide is then collected (step S15) and recovered (step S16). Step S17).

[0108] <Steps S18, S19, and S20> Also, a substance 94 is prepared for mixing in step S31. Prepare aluminum fluoride. Mix aluminum fluoride and acetone and crush (slurry). The aluminum fluoride is then collected (step S18) and recovered (step S19). (Step S20).

[0109] The aluminum fluoride is mixed with the material 91 during the subsequent annealing in step S34. The material 92 has an extremely small effect on the eutectic reaction and is therefore suitable as the material 94 .

[0110] <Step S25> In addition, a metal oxide 95 is prepared in step S25 for mixing in step S31. do.

[0111] It is preferable to use metal oxide 95 with few impurities. Metal oxide 95 containing metal A and transition metal Mt: The elements other than the above main components are considered impurities. For example, glow discharge mass spectrometry When analyzed by the method described above, it is preferable that the total concentration of impurities is 10,000 ppm wt or less. It is preferable that the content of the transition metals such as titanium and arsenic is 5000 ppm by weight or less. The total impurity concentration is preferably 3000 ppm wt or less, and 1500 ppm wt or less. It is more preferably m wt or less.

[0112] For example, as the metal oxide 95, lithium cobalt oxide particles ( The product name is Cellseed C-10N. This has an average particle size (D50) of The particle size is approximately 12 μm, and in the impurity analysis by glow discharge mass spectrometry (GD-MS), Magnesium and fluorine concentrations are 50 ppm wt or less, calcium and aluminum concentrations are The nickel concentration is 150 ppm wt or less. t or less, sulfur concentration is 500 ppm wt or less, arsenic concentration is 1100 ppm wt or less, The concentration of elements other than lithium, cobalt, and oxygen is 150 ppm wt or less. It is lithium cobalt oxide.

[0113] The metal oxide 95 in step S25 has a layered rock-salt type crystal structure with few defects and strains. Therefore, it is preferable that the metal oxide contains few impurities. If metal oxide 95 contains a large amount of impurities, it may result in a crystal structure with many defects or distortions. is high.

[0114] <Step S31> Next, the mixture 902, the metal oxide 95, the finely divided aluminum fluoride, and the finely divided aluminum fluoride are mixed. The nickel hydroxide is mixed (step S31 in FIG. 3).

[0115] The number of atoms TM of the transition metal Mt in the metal oxide 95 and the number of atoms of the element X in the mixture 902 The ratio of TM to TX is preferably TM:TX=1:y (0.005≦y≦0.05). , TM:TX=1:y (0.007≦y≦0.04), and more preferably TM: A ratio of TX=1:0.02 is more preferable.

[0116] The number of atoms of the transition metal Mt in the metal oxide 95 is TM, and the number of atoms of the metal M(2) in the material 94 is In step S31, (TM+T2):T2=1:z(0.000 5≦z≦0.02), and (TM+T2):T2=1:z(0.001 ≦y≦0.015), and (TM+T2):T2=1:z(0.0 01≦y≦0.009) is more preferred.

[0117] The number of atoms of the transition metal Mt in the metal oxide 95 is TM, and the number of atoms of the metal M(1) in the material 94 is In step S31, (TM+T1):T1=1:z(0.000 5≦z≦0.02), and (TM+T1):T1=1:z(0.001 ≦y≦0.015), and (TM+T1):T1=1:z(0.0 01≦y≦0.009) is more preferred.

[0118] The mixing in step S31 is carried out after the mixing in step S12 in order not to destroy the particles of the composite oxide. For example, it is preferable to set the rotation speed to be milder than that of the mixing in step S12. It is preferable to use conditions with less heat or shorter time. For mixing, a ball mill, a bead mill, etc. can be used. When using a ball mill, for example, zirconia balls should be used as the media. is preferred.

[0119] <Steps S32 and S33> The mixed materials are collected (step S32 in FIG. 3) to obtain a mixture 903 (step S32 in FIG. 3). Step S33).

[0120] <Step S34> Next, the mixture 903 is heated (step S34 in FIG. 3). It may be called baking.

[0121] The annealing is preferably carried out at a suitable temperature and time. The particle size and composition of the metal oxide 95 in step S25 vary depending on the conditions. Smaller offspring may prefer lower temperatures or shorter times than larger offspring. .

[0122] The annealing temperature is preferably equal to or higher than the temperature at which the mixture 902 melts. It is assumed that when the mixture 902 is annealed, the mixture 902 melts. For example, MgF2 (melting point 12 A mixture of LiF (melting point 63°C) and LiF (melting point 848°C) melts and distributes on the surface of the composite oxide particles. It is thought that the melting of MgF2 promotes the reaction with LiCoO2, resulting in the formation of LiM Therefore, the fluoride and the magnesium source form a eutectic mixture. A combination of the above is preferable.

[0123] The annealing temperature is preferably equal to or higher than the temperature at which the mixture 903 melts. A magnesium source (e.g., LiF), a magnesium source (e.g., MgF2), and a lithium oxide (e.g., L iCoO2) forms a covalent mixture, which is thought to promote the production of LiMO2. do.

[0124] The annealing temperature is set to a temperature at which an endothermic peak is observed by DSC as shown in FIG. 23, for example, The decomposition temperature of LiCoO2 is preferably 735°C or higher, and more preferably 820°C or higher. The temperature is about 1100℃, but at temperatures around that temperature, a small amount of LiCoO2 Therefore, for example, the annealing temperature should be 1050°C or less. is preferable, and 1000°C or less is more preferable.

[0125] Therefore, the annealing temperature is preferably 735°C or higher and 1050°C or lower. The temperature is preferably 820°C or higher and 1050°C or lower, and more preferably 820°C or higher and 1050°C or lower. A temperature of 0°C or higher and 1000°C or lower is more preferable.

[0126] The annealing time is preferably, for example, 3 hours or more, and more preferably 10 hours or more.

[0127] The temperature drop time after annealing is preferably, for example, 10 hours or more and 50 hours or less.

[0128] The diffusion of the elements contained in the mixture 903 occurs in the surface layer of the metal oxide 95 particles rather than in the interior of the particles. Therefore, magnesium and halogen atoms are more rapidly oxidized in the surface layer and near the grain boundaries. As will be described later, magnesium in the surface layer and near the grain boundaries is more highly concentrated than in the interior. When the concentration of cellulose is high, the change in the crystal structure can be more effectively suppressed. A positive electrode active material having a smooth surface and small surface roughness can be obtained.

[0129] <Steps S35 and S36> The annealed material is collected (step S35 in FIG. 3). The positive electrode active material 100 according to one embodiment of the present invention is produced by the above process. This can be done (step S36 in FIG. 3).

[0130] <Method 3 for producing positive electrode active material> An example of a method for manufacturing a positive electrode active material of one embodiment of the present invention will be described below with reference to FIGS. .

[0131] The manufacturing method shown in FIG. 4 is the same as that shown in FIG. 3 except for some differences, so the same parts will not be explained here. For the sake of brevity, we will omit it.

[0132] <Step S21> As shown in step S21 of FIG. 4, first, as materials for the mixture 904, the substance 91, the substance 92, a substance 93 and a substance 94 are prepared.

[0133] In this embodiment, lithium fluoride (LiF) is prepared as the substance 91, and fluorine is prepared as the substance 92. Prepare magnesium fluoride MgF2, prepare nickel hydroxide as substance 93, and prepare nickel hydroxide as substance 94. As the aluminum fluoride, aluminum fluoride is prepared (step S21).

[0134] The aluminum fluoride is mixed with the material 91 during the subsequent annealing in step S34. The material 92 has an extremely small effect on the eutectic reaction and is therefore suitable as the material 94 .

[0135] The likelihood of a eutectic reaction occurring also depends on the annealing atmosphere, pressure, and the processing conditions of the annealing device. This may vary depending on the total amount of material being annealed relative to the volume of the chamber. If the total amount of material being poured is large, then for more uniform processing, fill the It is preferable to use aluminum fluoride.

[0136] For example, if the total amount of powder is large, the surface of the powder is less likely to be exposed to the annealing atmosphere. Even in such a case, each reaction in the production of the positive electrode active material can be carried out more stably. To achieve this, it is preferable to use aluminum fluoride as material 94.

[0137] Also, a solvent is prepared for the subsequent wet mixing and grinding process. Acetone is used as the solvent. Use.

[0138] <Step S22> Next, the above materials are mixed and crushed (step S22 in FIG. 4). The mixing can be performed by dry or wet crushing. The wet method is preferable because it allows for finer pulverization. For example, a ball mill, a bead mill, etc. can be used. When a ball mill is used, For example, it is preferable to use zirconia balls as the media. It is preferable to carry out the above-mentioned step sufficiently to pulverize the material.

[0139] <Steps S23 and S24> The mixed and crushed materials are collected (step S23) to obtain a mixture 904 (step (P S24).

[0140] <Step S25> Furthermore, metal oxide 95 is used in step S25.

[0141] <Step S31> Next, the mixture 904 and the metal oxide 95 are mixed together (step S31).

[0142] The manufacturing procedure from step S31 onwards is the same as that shown in FIG. 3, so detailed explanations will be omitted. By following the manufacturing procedure from step S31 onwards, the positive electrode active material can be obtained in step S36. .

[0143] In this embodiment, steps S15 to S20 in FIG. 3 can be omitted. Cut.

[0144] <Cathode active material> Next, an example of the structure of the positive electrode active material will be described.

[0145] [Positive electrode active material structure 1] The positive electrode active material preferably contains a metal (hereinafter, element A) that serves as a carrier ion. Element A includes, for example, alkali metals such as lithium, sodium, and potassium, and calcium. Group 2 elements such as aluminum, beryllium, and magnesium can be used.

[0146] In the positive electrode active material, carrier ions are released from the positive electrode active material during charging. If there is a large amount of desorption, there are many ions that contribute to the capacity of the secondary battery, and the capacity increases. If there is a large amount of A elimination, the crystal structure of the compound contained in the positive electrode active material is likely to collapse. The collapse of the crystal structure may lead to a decrease in discharge capacity due to charge-discharge cycles. In one embodiment, the positive electrode active material contains the element X, and thus carrier ions are The collapse of the crystal structure during desorption may be suppressed. For example, element X may be partially Substituted at the A position. Element X is magnesium, calcium, zirconium, lanthanum. For example, elements such as copper, potassium, sodium, etc. can be used as the element X. Elements such as thorium and zinc can be used. Two or more of them may be used in combination.

[0147] The positive electrode active material of one embodiment of the present invention preferably contains a halogen in addition to the element X. It is preferable that the positive electrode active material of one embodiment of the present invention contains a halogen such as fluorine or chlorine. The presence of the halogen may promote substitution of element X at the position of element A. .

[0148] In addition, the positive electrode active material of one embodiment of the present invention has a valence that changes with charging and discharging of the secondary battery. The element Me is, for example, a transition metal. The positive electrode active material contains, for example, one or more of cobalt, nickel, and manganese as the element Me. In particular, cobalt is present. In addition, the element Me can be replaced with aluminum or other elements that do not change valence. and elements that can have the same valence as element Me, more specifically, trivalent typical elements, The aforementioned element X may be substituted at the position of the element Me. When the positive electrode active material of one embodiment is an oxide, the element X may substitute at the oxygen position.

[0149] As an example of the positive electrode active material of one embodiment of the present invention, a lithium composite having a layered rock salt crystal structure may be used. It is preferable to use an oxide. More specifically, for example, lithium oxide having a layered rock salt crystal structure is preferable. As for manganese composite oxides, lithium cobalt oxide, lithium nickel oxide, nickel, manganese and lithium composite oxides containing nickel, cobalt, and aluminum. In addition, these positive electrode active materials can be used as the space It is preferably represented by the group R-3m.

[0150] In the positive electrode active material with a layered rock salt crystal structure, the crystal structure collapses as the charge depth increases. Here, the breakdown of the crystal structure may be, for example, a shift in the layers. If this is irreversible, the capacity of the secondary battery may decrease with repeated charging and discharging. be.

[0151] By including the element X in the positive electrode active material of one embodiment of the present invention, for example, the depth of charge becomes deeper. By suppressing the misalignment, the volume of the layer can be reduced during charging and discharging. Therefore, the positive electrode active material of one embodiment of the present invention has excellent cycle life. Furthermore, the positive electrode active material of one embodiment of the present invention can achieve high charging characteristics. Therefore, the positive electrode active material of one embodiment of the present invention can have a stable crystal structure in a high voltage state. When the battery is kept in a charged state, short circuits may be less likely to occur. This is preferable because it further improves safety.

[0152] The positive electrode active material of one embodiment of the present invention has a sufficient discharge state and a high voltage charged state. The change in the crystal structure and the difference in volume when compared per the same number of transition metal atoms in small.

[0153] The positive electrode active material of one embodiment of the present invention has the chemical formula AM y O Z When expressed as (y>0, z>0) For example, lithium cobalt oxide is sometimes expressed as LiCoO2. Lithium nickelate is sometimes represented as LiNiO2.

[0154] In the positive electrode active material of one embodiment of the present invention containing element X, when the depth of charge is 0.8 or more, Although it is not a spinel-type crystal structure, it is represented by the space group R-3m and contains the element Me (e.g. ions of element X (e.g., magnesium) occupy the oxygen hexacoordinate positions, and cations In some cases, the arrangement of the ions has a symmetry similar to that of the spinel type. It is called a spinel-type crystal structure. In addition, the pseudo-spinel-type crystal structure is Oxygen may occupy 4-coordinated sites, and in this case the ionic arrangement also has a symmetry similar to that of the spinel type. It has.

[0155] The structure of the positive electrode active material becomes unstable due to the detachment of carrier ions during charging. The crystalline structure of the tetrahedron can maintain high stability even after the carrier ions are removed. It can be said that this structure can be used.

[0156] In the case of a high depth of charge of the present invention, the positive electrode active material having a pseudo-spinel structure is used as a secondary electrode. By using it in a battery, for example, at a voltage of about 4.6 V based on the potential of lithium metal, More preferably, the structure of the positive electrode active material is such that the voltage is about 4.65 V to 4.7 V. It is stable and can suppress the capacity decrease due to charging and discharging. For example, when graphite is used as the negative electrode active material, the voltage of the secondary battery must be 4.3V or higher. 5V or less, more preferably 4.35V or more and 4.55V or less, the positive electrode active material The structure is stable, and the capacity decrease due to charging and discharging can be suppressed.

[0157] The pseudospinel crystal structure has random Li between layers, but the CdCl2 type It can be said that this CdCl2-type similar crystal structure is The crystal structure is shown in Fig. 1 when lithium nickel oxide is charged to a charge depth of 0.94 (Li 0.06 Ni O2), but pure lithium cobaltate or cobalt-rich layered It is known that rock salt type positive electrode active materials do not usually have this crystal structure.

[0158] Layered rock salt crystals and the anions of rock salt crystals are in a cubic close-packed structure (face-centered cubic lattice structure) ) It is assumed that the anions in pseudospinel crystals also have a cubic close-packed structure. When they contact, there exists a crystal plane where the orientation of the cubic close-packed structure formed by the anions is aligned. However, the space group of layered rock salt crystals and pseudospinel crystals is R-3m, and The space groups of the rock salt crystals are Fm-3m (the common rock salt crystal space group) and Fd-3m (the simplest Since the space group is different from that of rock salt crystals, which have a perfect symmetry, the crystal plane must be The Lahr index is different between layered rock salt crystals and pseudospinel crystals and between rock salt crystals. In the layered rock salt crystal, pseudospinel crystal, and rock salt crystal, When the orientation of the cubic close-packed structure is aligned, the crystal orientation is roughly the same. There is.

[0159] The pseudospinel crystal structure has the coordinates of cobalt and oxygen in the unit cell as Co(0 ,0,0.5), O(0,0,x), 0.20≦x≦0.25. do.

[0160] In the positive electrode active material of one embodiment of the present invention, the volume of the unit cell at the depth of charge of 0 The difference in volume per unit cell between the pseudospinel crystal structure with a charge depth of 0.82 and the % or less, and more preferably 2.2% or less.

[0161] In the pseudospinel crystal structure, 2θ=19.30±0.20° (19.10° or more, 19 0.50° or less), and 2θ=45.55±0.10° (45.45° or more, 45.65° More specifically, a diffraction peak appears at 2θ=19.30±0.10° ( 19.20° or more and 19.40° or less), and 2θ=45.55±0.05° (45.5 A sharp diffraction peak appears at 0° or more and 45.60° or less.

[0162] Note that the positive electrode active material of one embodiment of the present invention has a pseudospinel crystal structure when charged at a high voltage. However, not all of the particles need to have a pseudospinel crystal structure. However, the XRD pattern may be read as follows: When belt analysis is performed, it is preferable that the pseudo-spinel type crystal structure is 50 wt% or more. It is more preferable that the content is 60 wt% or more, and even more preferable that the content is 66 wt% or more. The pseudo-spinel crystal structure is preferably 50 wt% or more, more preferably 60 wt% or more, and even more preferably If the content is preferably 66 wt % or more, the positive electrode active material will have sufficiently excellent cycle characteristics. can be done.

[0163] The number of atoms of the element X is preferably 0.001 times or more and 0.1 times or less the number of atoms of the element Me, and 0 More preferably, it is greater than 0.01 and less than 0.04, and even more preferably, it is about 0.02. The concentration of element X shown here is determined by, for example, measuring the element concentration of the entire particle of the positive electrode active material using ICP-MS or the like. It may be a value obtained by analysis, or may be a value based on the blending of raw materials in the process of producing the positive electrode active material. It's okay to do that.

[0164] When the element Me has cobalt and nickel, the atoms of cobalt and nickel The ratio of the number of nickel atoms (Ni) to the total number of atoms (Co+Ni) is Ni / (Co+Ni). is preferably less than 0.1, and more preferably 0.075 or less.

[0165] <Metal Oxide 95> Next, an example of a material that can be used as the metal oxide 95 will be described.

[0166] Various composite oxides can be used as the metal oxide 95. For example, LiFeO 2, LiCoO2, LiNiO2, LiMn2O4, Li2MnO3, V2O5, Cr2 Compounds such as O5 and MnO2 can be used.

[0167] As an example of a material with a layered rock salt crystal structure, the composite oxide represented by LiMO2 is The element M is preferably at least one selected from Co and Ni. LiCoO2 has a large capacity, is stable in the atmosphere, and is relatively thermally stable. In addition, the element M is preferably selected from Co and Ni. In addition to one or more of the above, it may contain one or more selected from Al and Mn.

[0168] For example, LiNi x Mn y Co z O w (x, y, z and w are respectively, for example, x=y= z=1 / 3 or its vicinity, w=2 or its vicinity) can be used. Ba, LiNi x Mn y Co z O w (x, y, z and w are respectively, for example, x=0.8 or is its vicinity, y=0.1 or its vicinity, z=0.1 or its vicinity, w=2 or its vicinity In addition, for example, LiNi x Mn y Co z O w (x, y, z and w are, for example, x=0.5 or its vicinity, y=0.3 or its vicinity, and z= 0.2 or thereabouts, w=2 or thereabouts) can be used. LiNi x Mn y Co z O w (x, y, z and w are respectively, e.g. x=0.6 or neighborhood, y=0.2 or its neighborhood, z=0.2 or its neighborhood, w=2 or its neighborhood ) can be used. For example, LiNi x Mn y Co z O w (x, y, z and and w are, for example, x=0.4 or its vicinity, y=0.4 or its vicinity, and z=0. 2 or thereabouts, w=2 or thereabouts) can be used.

[0169] The neighborhood is, for example, a value that is greater than 0.9 times and less than 1.1 times the value.

[0170] In addition, as the metal oxide 95, for example, a solid solution of a combination of multiple composite oxides may be used. For example, LiNi x Mn y Co z O2(x, y, z>0, x+y+z=1) and Li2MnO3 solid solutions can be used.

[0171] An example of a material with a spinel-type crystal structure is a composite oxide represented by LiM2O4. It is preferable to use Mn as the element M. For example, LiMn2 Furthermore, by including Ni in addition to Mn as the element M, This is preferable because it may improve the discharge voltage of the secondary battery and improve the energy density. A lithium-containing material having a spinel-type crystal structure containing manganese, such as LiMn2O4, A small amount of lithium nickel oxide (LiNiO2 or LiNi 1-x M x O2(M=Co, Al etc. )) is preferably mixed, since it is possible to improve the characteristics of the secondary battery.

[0172] For example, the average particle diameter of the primary particles of the metal oxide 95 is 1 nm or more and 100 μm or less. It is preferable that the thickness is 50 nm or more and 50 μm or less, and more preferable that the thickness is 1 μm or more and 30 μm or less. It is more preferable that the specific surface area is 1 m or less. 2 / g or more 20m 2 / g or less It is preferable that the average particle size of the secondary particles is 5 μm or more and 50 μm or less. The average particle size is preferably measured by observation using a SEM (scanning electron microscope) or a TEM. Alternatively, it can be measured by a particle size distribution analyzer using a laser diffraction / scattering method. The specific surface area can be measured by a gas adsorption method.

[0173] A conductive material such as a carbon layer may be provided on the surface of the metal oxide 95. The conductivity of the electrode can be improved by providing a material such as metal oxide 95 The carbon layer coating on the metal oxide 95 is achieved by mixing carbohydrates such as glucose during the calcination process. In addition, the conductive material can be graphene, multi-graphene, acid Reduced graphene (GO) or RGO (Reduced Graphene Oxide) Here, RGO is, for example, grafted olefin oxide. It refers to a compound obtained by reducing GO.

[0174] The surface of the metal oxide 95 may be provided with a layer having one or more of an oxide or a fluoride. The oxide may have a different composition than the metal oxide 95. They may have the same composition.

[0175] For example, a polyanion-based material having oxygen, element X, metal A, and metal M may be used. The metal M can be Fe, Mn, Co, Ni, Ti, V, or Nb. The metal A is one or more of Li, Na, and Mg, and the element X is S, P, Mo, or W. , As, and Si.

[0176] Examples of materials having an olivine-type crystal structure include composite materials (general formula LiMPO4(M This can be achieved by using one or more of Fe(II), Mn(II), Co(II), and Ni(II). This is possible. Representative examples of the general formula LiMPO4 include LiFePO4, LiNiPO4, LiCoPO4, LiMnPO4, LiFe a Ni b PO4, LiFe a Co b PO4, LiFe a Mn b PO4, LiNi a Co b PO4, LiNi a Mn b PO4 (a + b is 1 or less, 0 < a < 1, 0 < b < 1), LiFe c Ni d Co e PO4, LiFe c Ni d Mn e PO4, LiNi c Co d Mn e PO4 (c + d + e is 1 or less, 0 < c < 1, 0 < d < 1, 0 < e < 1), LiFe f Ni g Co h Mn i PO4 (f + g + h + i is 1 or less , 0 < f < 1, 0 < g < 1, 0 < h < 1, 0 < i < 1), etc. Lithium compounds can be used. This is possible.

[0177] Materials having an olivine-type crystal structure, for example, preferably have an average particle diameter of primary particles of 1 nm or more and 2 0 μm or less, more preferably 10 nm or more and 5 μm or less, even more preferably 50 nm or more and 2 μm or less. Also, the specific surface area is preferably 1 m 2 / g or more and 20 m 2 / g or less. Further, the average particle diameter of secondary particles is preferably 5 μm or more and 50 μ m or less.

[0178] Also, the general formula Li (2-j) MSiO4 (M is Fe(II), Mn(II), Co( A composite material such as one or more of Ni(II), Ni(II), 0≦j≦2) can be used. Formula Li (2-j) A typical example of MSiO4 is Li (2-j) FeSiO4, Li (2 -j) NiSiO4, Li (2-j) CoSiO4, Li (2-j) MnSiO4, Li (2-j) Fe k Ni l SiO4, Li (2-j) Fe k Co l SiO4, Li (2-j ) Fe k Mn l SiO4, Li (2-j) Ni k Co l SiO4, Li (2-j) Ni k Mn l SiO4 (k+l is 1 or less, 0 <k<1、0<l<1)、Li (2-j) Fe m N i n Co q SiO4, Li (2-j) Fe m Ni n Mn q SiO4, Li (2-j) Ni m Co n Mn q SiO4 (m+n+q is 1 or less, 0 <m<1、0<n<1、0<q<1) , Li (2-j) Fe r Ni s Co t Mn u SiO4 (r+s+t+u is less than 1, 0 <r <1, 0 < s < 1, 0 < t < 1, 0 < u < 1), etc. lithium compounds can be used as materials and can be achieved.

[0179] Also, A x M2(XO4)3 (A = Li, Na, Mg, M = Fe, Mn, Ti, V, N b, X = S, P, Mo, W, As, Si) of the general formula can be used as the NASICON-type compound. Examples of NASICON-type compounds include Fe2(MnO4)3, Fe2(SO4)3 , Li3Fe2(PO4)3, etc. Also, as the metal oxide 95, compounds represented by the general formula Li2MPO4F , Li2MP2O7, Li5MO4 (M = Fe, Mn) can be used and can be achieved.

[0180] Also, as the metal oxide 95, perovskite-type fluorides such as NaFeF3, FeF3 , metal chalcogenides (sulfides, selenides, tellurides) such as TiS2, MoS2, L iMVO4 and other oxides having an inverse spinel-type crystal structure, vanadium oxide-based (V2O5 , V6O 13 , LiV3O8, etc.), manganese oxide, organic sulfur compounds, etc. can be used and can be achieved.

[0181] Also, as the metal oxide 95, borate-based cathode materials represented by the general formula LiMBO3 (M is Fe(II), Mn(II ), Co(II)) can be used.

[0182] Also, as the metal oxide 95, the lithium a manganese composite oxide which can be represented by the composition formula Li b M c O d can be used. Here, the element M is lithium, manganese, etc. and can be achieved. It is preferable to use a metal element selected from the outside, silicon, or phosphorus, and nickel is the preferred It is more preferable to measure the entire particle of the lithium manganese composite oxide. , 0 <a / (b+c)<2、かつc>0 during discharge, and 0.26≦(b+c) / d<0. It is preferable that the crystallinity is 5.0 in the surface layer and the center in order to realize high capacity. A lithium manganese composite oxide having regions with different structures, crystal orientations, or oxygen contents. To obtain such a lithium manganese composite oxide, for example, 1. It is preferable that 6≦a≦1.848, 0.19≦c / b≦0.935, and 2.5≦d≦3. It's nice.

[0183] Examples of materials containing sodium include NaFeO2 and Na 2 / 3 [Fe 1 / 2 Mn 1 / 2 ]O2, Na 2 / 3 [Ni 1 / 3 Mn 2 / 3 ]O2, Na2Fe2(SO4)3, Na3V2(PO4)3, Na2FePO4F, NaVPO4F, NaMPO4 (M is Fe(II), Mn(II), Co(II), Ni(II)), Na2FePO4F, N Sodium-containing oxides such as a4Co3(PO4)2P2O7 are used as metal oxides 95. It can be used.

[0184] Furthermore, lithium-containing metal sulfide can be used as the metal oxide 95. For example, , Li2TiS3, Li3NbS4, etc.

[0185] This embodiment mode can be implemented in appropriate combination with other embodiment modes.

[0186] (Embodiment 2) ​In this embodiment, a secondary battery having the positive electrode active material 100 described in the previous embodiment is used. In this embodiment, examples of materials that can be used for the positive electrode, the negative electrode, and the electrolyte will be described. A secondary battery in which the electrolyte is enclosed in an exterior body will be described as an example.

[0187] [Positive electrode] The positive electrode has a positive electrode active material layer and a positive electrode current collector.

[0188] <Cathode active material layer> The positive electrode active material layer contains at least a positive electrode active material. In addition, other substances such as a coating on the surface of the active material, a conductive additive, or a binder may be included.

[0189] As the positive electrode active material, the positive electrode active material 100 described in the previous embodiment can be used. By using the positive electrode active material 100 described in the previous embodiment, it is possible to achieve high capacity and cycle characteristics. Therefore, a secondary battery having excellent properties can be obtained.

[0190] As the conductive additive, a carbon material, a metal material, a conductive ceramic material, or the like may be used. Furthermore, a fibrous material may be used as the conductive additive. The content of the conductive additive is preferably 1 wt% or more and 10 wt% or less, and more preferably 1 wt% or more and 5 wt% or less. Below is more preferable.

[0191] The conductive additive can form an electrically conductive network in the active material layer. The auxiliary agent can maintain the electrical conduction path between the positive electrode active materials. By adding a conductive additive, it is possible to realize an active material layer with high electrical conductivity. do.

[0192] Examples of the conductive additive include natural graphite, artificial graphite such as mesocarbon microbeads, and carbon. Examples of carbon fibers include mesophase pitch carbon fibers. Carbon fibers such as carbon fibers, isotropic pitch-based carbon fibers, etc. can be used. Carbon nanofibers, carbon nanotubes, etc. can be used. The nanotubes can be produced by, for example, a vapor phase growth method. For example, carbon black (acetylene black (AB) etc.), graphite particles Carbon materials such as silicon, graphene, and fullerene can be used. Metal powders and fibers such as nickel, aluminum, silver, and gold, as well as conductive ceramic materials can be used.

[0193] A graphene compound may also be used as the conductive additive.

[0194] Graphene compounds have excellent electrical properties, such as high conductivity, as well as high flexibility and In some cases, the graphene has excellent physical properties, such as high mechanical strength. Graphene compounds have a planar shape. Graphene compounds enable surface contact with low contact resistance. In addition, even if the material is thin, it can have very high conductivity, and a small amount can be used efficiently in the active material layer. Therefore, graphene compounds are used as conductive additives. This is preferable because it is possible to increase the contact area between the active material and the conductive additive. By using a spray-drying device, the entire surface of the active material is covered with graphene, a conductive additive. It is preferable to form the compound as a coating. In addition, electrical resistance may be reduced. Here, examples of the graphene compound include graphene, multigraphene, and the like. It is particularly preferable to use RGO, which may be, for example, graphene oxide ( This refers to a compound obtained by reducing graphene oxide (GO).

[0195] When using an active material with a small particle size, for example, an active material with a particle size of 1 μm or less, the specific surface area of ​​the active material Therefore, a large amount of conductive additive is required. This tends to result in a relatively reduced amount of active material carried. If the amount of the conductive additive decreases, the capacity of the secondary battery will decrease. When graphene compounds are used, they can efficiently form conductive paths even in small amounts. This is particularly preferable because it is possible to avoid reducing the amount of the active material carried.

[0196] As the graphene compound, for example, graphene or multi-graphene may be used. Therefore, it is preferable that the graphene compound has a sheet-like shape. The composite is composed of multiple multi-graphenes or (and) multiple graphenes partially overlapping each other. It may be in the form of a sheet.

[0197] In the vertical cross section of the active material layer, sheet-like graphite is distributed almost uniformly inside the active material layer. It is preferable that the plurality of graphene compounds are dispersed in the plurality of granular positive electrode active materials. The positive electrode active material is formed so as to partially cover the surface of the positive electrode active material or to adhere to the surface of multiple granular positive electrode active material. Preferably, they are in surface contact with each other.

[0198] Here, a plurality of graphene compounds are bonded to each other to form a mesh-like graphene compound. forming a graphene compound net or graphene net. When the active material is covered with a graphene net, the graphene net can Therefore, the amount of binder can be reduced. This allows for the active material to be used in a smaller amount or not in a larger amount, reducing the proportion of the active material in the electrode volume or weight. The ratio can be improved, that is, the capacity of the secondary battery can be increased.

[0199] Here, graphene oxide is used as the graphene compound and mixed with an active material to form an active material layer. It is preferable to form a layer of the graphene compound and then reduce the layer. By using graphene oxide, which has extremely high dispersibility, the graphene compound can be easily incorporated into the active material layer. It can be dispersed uniformly inside. It contains uniformly dispersed graphene oxide. The solvent is evaporated from the dispersion medium and graphene oxide is reduced, so that the remaining graphene in the active material layer is The graphene compounds are dispersed to the extent that they overlap and come into surface contact with each other, The reduction of graphene oxide can be achieved by, for example, heat treatment. This may be done by conventional methods or by using a reducing agent.

[0200] Therefore, unlike granular conductive additives such as acetylene black, which come into point contact with the active material, Since the phene compound enables surface contact with low contact resistance, it is more effective than ordinary conductive additives. A small amount can improve the electrical conductivity between the granular positive electrode active material and the graphene compound. Therefore, the ratio of the positive electrode active material in the active material layer can be increased. The discharge capacity of the secondary battery can be increased.

[0201] In addition, by using a spray dryer in advance, the entire surface of the active material is covered with the conductive additive. The graphene compound is formed as a coating, and the active material is further bonded to the graphene compound. A conductive path can also be formed.

[0202] Examples of binders include styrene-butadiene rubber (SBR) and styrene-isopropyl Ethylene-styrene rubber, acrylonitrile-butadiene rubber, butadiene rubber, ethylene- It is preferable to use a rubber material such as a propylene-diene copolymer. For this purpose, fluororubber can be used.

[0203] As the binder, it is preferable to use, for example, a water-soluble polymer. As the molecule, for example, polysaccharides can be used. cellulose (CMC), methylcellulose, ethylcellulose, hydroxypropyl Cellulose, diacetyl cellulose, regenerated cellulose and other cellulose derivatives, as well as starch In addition, these water-soluble polymers can be used in combination with the above-mentioned rubber materials. It is more preferable to use

[0204] Alternatively, the binder may be polystyrene, polymethyl acrylate, or polymethacrylic acid. Methyl (Polymethyl methacrylate, PMMA), Sodium polyacrylate, Polyvinyl Polyvinyl alcohol (PVA), polyethylene oxide (PEO), polypropylene oxide, Polyimide, polyvinyl chloride, polytetrafluoroethylene, polyethylene, polypropylene Polyethylene, polyisobutylene, polyethylene terephthalate, nylon, polyvinylidene fluoride Polyvinyl chloride (PVDF), polyacrylonitrile (PAN), ethylene propylene diene polymer It is preferable to use materials such as polyvinyl acetate and nitrocellulose.

[0205] The binder may be used in combination with two or more of the above.

[0206] For example, a material having a particularly excellent viscosity adjusting effect may be used in combination with other materials. For example, rubber materials have excellent adhesive strength and elasticity, but it is difficult to adjust the viscosity when mixed with a solvent. In such cases, for example, mixing with a material that has a particularly excellent viscosity adjusting effect can be As a material having a particularly excellent viscosity adjusting effect, for example, a water-soluble polymer is preferably used. Furthermore, examples of water-soluble polymers that are particularly effective in adjusting viscosity include the aforementioned polysaccharides, such as cellulose, cellulose acetate, and the like. Carboxymethylcellulose (CMC), methylcellulose, ethylcellulose, hydroxymethylcellulose Cellulose derivatives such as hydroxypropyl cellulose, diacetyl cellulose, and regenerated cellulose Conductive materials and starch can be used.

[0207] The cellulose derivatives such as carboxymethyl cellulose are, for example, The solubility increases when cellulose is converted into salts such as sodium salts or ammonium salts. The increased solubility of the solubility of the electrode makes it easier to achieve the desired viscosity. It is also possible to improve the dispersibility of the active material and other components when preparing the battery. In the present invention, the cellulose and cellulose derivatives used as binders for the electrodes include: The salts thereof are also included.

[0208] Water-soluble polymers stabilize viscosity by dissolving in water, and also work well with active materials and binders. Other materials to be combined, such as styrene butadiene rubber, are stable in aqueous solution. In addition, since it has functional groups, it is easily and stably adsorbed onto the surface of the active material. It is expected that cellulose derivatives such as carboxymethyl cellulose can be Many materials have functional groups such as hydroxyl groups and carboxyl groups. It is expected that the polymers will interact with each other and widely cover the surface of the active material.

[0209] When the binder that covers or contacts the surface of the active material forms a film, it is called a passive film. It is expected that the passive film will also act as a barrier to prevent the decomposition of the electrolyte. A film with no electrical conductivity or extremely low electrical conductivity, for example, on the surface of an active material When a passive film is formed, it is possible to suppress the decomposition of the electrolyte at the battery reaction potential. In addition, the passive film suppresses electrical conductivity and does not allow lithium ions to be conducted. It is even more desirable to

[0210] <Positive electrode current collector> The positive electrode current collector may be made of metals such as stainless steel, gold, platinum, aluminum, titanium, etc. Highly conductive materials such as these alloys can be used. It is preferable that silicon, titanium, neodymium, scavenger, etc. are not eluted at the potential of the positive electrode. Aluminum alloys containing elements such as indium and molybdenum that improve heat resistance are used. It can also be formed from a metal element that reacts with silicon to form silicide. Metal elements that react with silicon to form silicide include zirconium, titanium, and Tantalum, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten , cobalt, nickel, etc. Current collectors are available in foil, plate (sheet), mesh, and punched shapes. The current collector may be in the form of a metal, an expanded metal, or the like. It is recommended to use a thickness of 5 μm or more and 30 μm or less.

[0211] [Negative electrode] The negative electrode has a negative electrode active material layer and a negative electrode current collector. and a binder.

[0212] <Negative electrode active material> As the negative electrode active material, for example, an alloy-based material or a carbon-based material can be used.

[0213] As a negative electrode active material, it can carry out charge-discharge reactions by alloying and dealloying reactions with lithium. Any element can be used, such as silicon, tin, gallium, aluminum, Germanium, lead, antimony, bismuth, silver, zinc, cadmium, indium, etc. Materials containing at least one of these elements can be used. These elements have a higher capacity than carbon. Silicon has a particularly high theoretical capacity of 4200mAh / g. Silicon is preferably used, and compounds containing these elements may also be used. For example, SiO, Mg2Si, Mg2Ge, SnO, SnO2, Mg2Sn, SnS2, V2Sn3, FeSn2, CoSn2, Ni3Sn2, Cu6Sn5, Ag3Sn, Ag 3Sb, Ni2MnSb, CeSb3, LaSn3, La3Co2Sn7, CoSb3, Examples include InSb and SbSn. Here, charging and discharging occurs through alloying and dealloying reactions with lithium. Elements that can undergo a reaction and compounds containing such elements are sometimes called alloy materials. be.

[0214] In this specification, SiO refers to, for example, silicon monoxide. Alternatively, SiO refers to Si O x Here, x preferably has a value close to 1. Alternatively, x is, for example, preferably 0.2 or more and 1.5 or less, and more preferably 0.3 or more and 1.2 or less.

[0215] Carbon materials include graphite, easily graphitizable carbon (soft carbon), and non-graphitizable carbon (hard carbon). carbon nanotubes, graphene, carbon black, etc. stomach.

[0216] Examples of graphite include artificial graphite and natural graphite. Examples include carbon microbeads (MCMB), coke-based artificial graphite, and pitch-based artificial graphite. Here, spherical graphite having a spherical shape can be used as the artificial graphite. For example, the MCMB may have a spherical shape, which is preferable. It is relatively easy to reduce the product, which is sometimes preferable. , flake graphite, and spherical natural graphite.

[0217] When lithium ions are inserted into graphite (the formation of lithium-graphite intercalation compounds), ) shows a low potential similar to that of lithium metal (0.05V to 0.3V vs.Li / Li + This allows lithium-ion secondary batteries to exhibit high operating voltages. Furthermore, graphite has a relatively high capacity per unit volume, a relatively small volume expansion, and is inexpensive. It is preferable because it has advantages such as higher safety compared to lithium metal.

[0218] In addition, titanium dioxide (TiO2) and lithium titanium oxide (Li4 Ti5O 12 ), lithium-graphite intercalation compound (Li x C6), niobium pentoxide (Nb2O5 ), tungsten oxide (WO2), molybdenum oxide (MoO2), etc. can be done.

[0219] In addition, the negative electrode active material is a composite nitride of lithium and transition metals, which has a Li3N structure. つLi 3-x M x N (M=Co, Ni, Cu) can be used. For example, Li 2. 6Co 0.4 N3 has a large charge / discharge capacity (900mAh / g, 1890mAh / cm 3 )of This is preferable.

[0220] When a composite nitride of lithium and transition metals is used, lithium ions are included in the negative electrode active material, As a positive electrode active material, materials that do not contain lithium ions, such as V2O5 and Cr3O8, are used. In addition, when a material containing lithium ions is used as the positive electrode active material, However, by first removing the lithium ions contained in the positive electrode active material, As the lithium-transition metal nitride, a complex nitride of lithium and a transition metal can be used.

[0221] In addition, a material that undergoes a conversion reaction can also be used as the negative electrode active material. For example, lithium oxides such as cobalt oxide (CoO), nickel oxide (NiO), and iron oxide (FeO) A transition metal oxide that does not form an alloy with aluminum may be used as the negative electrode active material. Further materials that produce this include Fe2O3, CuO, Cu2O, RuO2, and Cr2O3 oxides such as CoS 0.89 , NiS, CuS and other sulfides, Zn3N2, Cu3N, Ge Nitrides such as 3N4, phosphides such as NiP2, FeP2, CoP3, FeF3, BiF3, etc. This also occurs with fluoride.

[0222] The conductive additive and binder that the negative electrode active material layer can have are: The same materials as the conductive additive and binder that can be used can be used.

[0223] <Negative electrode current collector> The negative electrode current collector can be made of the same material as the positive electrode current collector. It is preferable to use a material that does not alloy with carrier ions such as lithium.

[0224] [Electrolyte] The electrolytic solution contains a solvent and an electrolyte. The solvent for the electrolytic solution is preferably an aprotic organic solvent. Preferably, for example, ethylene carbonate (EC), propylene carbonate (PC), Ethylene carbonate, chloroethylene carbonate, vinylene carbonate, gamma-butyro Lactone, γ-valerolactone, dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), methyl formate, methyl acetate, ethyl acetate methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, 1,3-dioxane, 1,4-dioxane, dimethoxyethane (DME), dimethyl sulfone oxide, diethyl ether, methyl diglyme, acetonitrile, benzonitrile, tetrahydrofuran One of tetrahydrofuran, sulfolane, sultone, etc., or two or more of these can be used in combinations and ratios of:

[0225] In addition, a flame-retardant and non-volatile ionic liquid (room-temperature molten salt) is used as the solvent for the electrolyte. By using one or more, the internal temperature of the secondary battery can be prevented from rising due to an internal short circuit or overcharging. Even if the battery is heated, it can prevent explosion and fire of the secondary battery. The electrolyte solution is made of tetravalent cations and anions. ammonium cations, tertiary sulfonium cations, and quaternary phosphonium cations Aliphatic onium cations such as imidazolium cations and pyridinium cations The following aromatic cations are also used as anions in electrolytes: monovalent amide-based Anions, monovalent methide anions, fluorosulfonate anions, perfluoroalkanes perfluoroalkyl borate anion, tetrafluoroborate anion, perfluoroalkyl bo ... phosphate anion, hexafluorophosphate anion, or perfluoroalkyl phosphate hydrate anions, etc.

[0226] The electrolyte to be dissolved in the solvent is, for example, LiPF6, LiClO4, L iAsF6, LiBF4, LiAlCl4, LiSCN, LiBr, LiI, Li2SO 4. Li2B 10 Cl 10 , Li2B 12 Cl 12 , LiCF3SO3, LiC4F9S O3, LiC(CF3SO2)3, LiC(C2F5SO2)3, LiN(CF3SO2 )2, LiN(C4F9SO2)(CF3SO2), LiN(C2F5SO2)2, etc. One or more of these titanium salts may be used in any combination and ratio. This can be done.

[0227] The electrolyte used in secondary batteries is free from granular dust and elements other than the constituent elements of the electrolyte (hereinafter simply referred to as " It is preferable to use a highly purified electrolyte solution with a low content of impurities. Specifically, the weight ratio of impurities to the electrolyte is 1% or less, preferably 0.1% or less, more preferably 1% or less. It is preferably 0.01% or less.

[0228] In addition, the electrolyte contains vinylene carbonate, propane sultone (PS), and tert-butyl Benzene (TBB), Fluoroethylene carbonate (FEC), Lithium bis(oxa) Lithium borate (LiBOB), as well as dinitriles such as succinonitrile and adiponitrile The concentration of the additives may be, for example, The content should be between 0.1 wt% and 5 wt%.

[0229] Alternatively, a polymer gel electrolyte may be used in which a polymer is swollen with an electrolytic solution.

[0230] The use of polymer gel electrolyte increases safety against leakage etc. The pond can be made thinner and lighter.

[0231] Gelled polymers include silicone gel, acrylic gel, and acrylonitrile gel. , polyethylene oxide gel, polypropylene oxide gel, fluorine-based polymer A gel or the like can be used.

[0232] Examples of polymers include polyalkylene oxides such as polyethylene oxide (PEO). Polymers with side structures, PVDF, polyacrylonitrile, etc., and their For example, a copolymer containing PVDF and hexafluoropropylene ( PVDF-HFP, a copolymer of PVDF and HFP, can be used. The polymer may have a porous shape.

[0233] In addition, instead of the electrolytic solution, a solid electrolyte containing an inorganic material such as a sulfide or oxide, It is possible to use a solid electrolyte containing a polymer material such as PEO (polyethylene oxide). When a solid electrolyte is used, there is no need to install a separator or spacer. Since the entire battery can be solidified, there is no risk of leakage, dramatically improving safety.

[0234] Sulfide-based solid electrolytes include thiosilicon-based (Li 10 GeP2S 12 , Li 3.25 G e 0.25 P 0.75 S4, etc.), sulfide glass (70Li2S・30P2S5, 30Li 2S·26B2S3·44LiI, 63Li2S·38SiS2·1Li3PO4, 57 Li2S・38SiS2・5Li4SiO4, 50Li2S・50GeS2, etc.), sulfides Glass-ceramic (Li7P3S 11 , Li 3.25 P 0.95 S4, etc.) are included. Solid electrolytes based on ZnO have high conductivity, can be synthesized at low temperatures, and are relatively soft. Because it is soft, it has the advantage of easily maintaining conductive paths even after charging and discharging.

[0235] Oxide-based solid electrolytes include materials with a perovskite crystal structure (La 2 / 3-x L i 3x TiO3, etc.), materials with NASICON-type crystal structure (Li 1+x Al x Ti2 -x (PO4)3, etc.), materials with garnet-type crystal structure (Li7La3Zr2O 12 etc.), materials with LISICON-type crystal structure (Li 14 ZnGeO 16 etc.), LLZ O(Li7La3Zr2O 12 ), oxide glasses (Li3PO4-Li4SiO4, 50 Li4SiO4·50Li3BO3, etc.), oxide crystallized glasses (Li 1.07 Al 0.6 9Ti 1.46 (PO4)3, Li 1.5 Al 0.5 Ge 1.5 (PO4)3, etc.) are included. Oxide-based solid electrolytes have the advantage of being stable in the atmosphere.

[0236] Halide-based solid electrolytes include LiAlCl4, Li3InBr6, LiF, LiC l, LiBr, LiI, etc. Also, composite materials in which these halide-based solid electrolytes are filled in the pores of porous alumina or porous silica can also be used as solid electrolytes.

[0237]

[0238] Also, different solid electrolytes may be mixed and used.

[0238] Among them, Li 1+x Al x Ti 2-x (PO4)3 (0 < x < 1) (hereinafter, LATP) contains aluminum and titanium, which are elements that the cathode active material used in the secondary battery of one aspect of the present invention may have. Therefore, a synergistic effect can be expected for improving the cycle characteristics, which is preferable. Also, an improvement in productivity due to the reduction of processes can be expected. In this specification, etc., the NASICON-type crystal structure is a compound represented by M2(XO4)3 (M: transition metal, X: S, P, As, Mo, W, etc.), and refers to a structure in which MO6 octahedra and XO4 tetrahedra share vertices and are three-dimensionally arranged. ​​​​​​​​ The secondary battery preferably has a separator. Examples of the separator include: Paper, nonwoven fabric, glass fiber, ceramics, or nylon (polyamide), vinylon (polyamide) vinyl alcohol fiber), polyester, acrylic, polyolefin, polyurethane The separator can be made of synthetic fibers or the like. It is preferable to process the electrode into a shape and place it so as to wrap either the positive electrode or the negative electrode.

[0240] The separator may have a multi-layer structure. For example, the separator may be made of an organic material such as polypropylene or polyethylene. The material film is made of ceramic material, fluorine material, polyamide material, or a combination of these. The ceramic material can be, for example, aluminum oxide. Examples of the fluorine-based material include aluminum particles, silicon oxide particles, etc. For example, PVDF, polytetrafluoroethylene, etc. can be used. For example, nylon, aramid (meta-aramid, para-aramid), etc. can be done.

[0241] Coating with ceramic materials improves oxidation resistance, making it possible to use separators during high-voltage charging and discharging. This suppresses the deterioration of the battery and improves the reliability of the secondary battery. Coating the separator and electrodes makes them adhere more easily, improving output characteristics. Coating polyamide materials, especially aramid, improves heat resistance, making it suitable for secondary batteries. Safety can be improved.

[0242] For example, a mixture of aluminum oxide and aramid is coated on both sides of a polypropylene film. Alternatively, aluminum oxide may be applied to the surface of the polypropylene film that comes into contact with the positive electrode. The surface that comes into contact with the negative electrode may be coated with a mixed material of rubber and aramid, and a fluorine-based material may be coated on the surface that comes into contact with the negative electrode. .

[0243] By using a multilayer separator, the safety of the secondary battery can be maintained even if the overall thickness of the separator is thin. Since the capacity per unit volume of the secondary battery can be increased,

[0244] [Exterior body] The exterior of the secondary battery is made of a metal material such as aluminum or a resin material. Also, a film-like outer casing can be used. , such as polyethylene, polypropylene, polycarbonate, ionomer, polyamide On the film made of such material, a highly flexible material such as aluminum, stainless steel, copper, or nickel is applied. A metal thin film is provided, and a polyamide resin or polyester is further provided on the metal thin film as the outer surface of the exterior body. A film having a three-layer structure provided with an insulating synthetic resin film such as a terephthalate resin can be used.

[0245] (Embodiment 3) In this embodiment, the secondary battery having the positive electrode active material 100 described in the previous embodiment is The materials used in the secondary battery described in this embodiment are the same as those in the previous embodiment. The description of the form can be taken into consideration.

[0246] [Coin-type secondary battery] First, an example of a coin-type secondary battery will be described. Figure 5A shows a coin-type (single-layer flat type) FIG. 5B is a cross-sectional view of the secondary battery.

[0247] The coin-type secondary battery 300 has a positive electrode can 301 that also serves as a positive electrode terminal and a negative electrode can 302 that also serves as a negative electrode terminal. The can 302 is insulated and sealed with a gasket 303 made of polypropylene or the like. The positive electrode 304 is composed of a positive electrode current collector 305 and a positive electrode active material layer 30 provided in contact with the positive electrode current collector 305. The negative electrode 307 is formed by a negative electrode current collector 308 and a negative electrode current collector 308 which is set in contact with the negative electrode current collector 308. The negative electrode active material layer 309 is formed by the bonding.

[0248] The positive electrode 304 and the negative electrode 307 used in the coin-type secondary battery 300 are active The material layer only needs to be formed on one side.

[0249] The positive electrode can 301 and the negative electrode can 302 are made of nickel and aluminum, which are corrosion-resistant to the electrolyte. Metals such as aluminum and titanium, or alloys of these and other metals (e.g., stainless steel) In addition, nickel or aluminum can be used to prevent corrosion by the electrolyte. The positive electrode can 301 is preferably coated with a positive electrode 304, and the negative electrode can 302 is preferably coated with a negative electrode 305. 07 and electrically connect to each other.

[0250] The negative electrode 307, the positive electrode 304, and the separator 310 are impregnated with an electrolyte, and as shown in FIG. 5B As shown, the positive electrode can 301 is placed downwards, and the positive electrode 304, separator 310, negative electrode 307, and negative electrode The cans 302 are stacked in this order, and the positive electrode can 301 and the negative electrode can 302 are secured together with a gasket 303 interposed therebetween. The coin-type secondary battery 300 is manufactured by crimping.

[0251] By using the positive electrode active material described in the previous embodiment for the positive electrode 304, high capacity and cycle The coin-type secondary battery 300 can have excellent battery characteristics.

[0252] Here, the flow of current during charging of a secondary battery will be explained using FIG. 5C. When the battery is considered as a closed circuit, the movement of lithium ions and the flow of current 78i are in the same direction. In secondary batteries that use lithium, the anode and cathode are connected by charging and discharging. The cathode and the oxidation reaction are reversed, and the reaction potential is The electrode with a higher reaction potential is called the positive electrode, and the electrode with a lower reaction potential is called the negative electrode. In this case, even during charging, discharging, or when a reverse pulse current is applied, Even when a charging current is flowing, the positive electrode is called the "positive electrode" or "+ electrode (plus electrode)" and the negative electrode is called the "+ electrode (plus The electrode is called the "negative electrode" or "-electrode (minus electrode)." The terms anode and cathode are used to describe the relationship between the two electrodes during charging and discharging. Therefore, the anode and cathode are not The term "anode" (negative electrode) will not be used in this specification. When using the terms "positive electrode" or "negative electrode," specify whether it is during charging or discharging. It will also be noted whether it corresponds to the positive pole or the negative pole.

[0253] A charger is connected to the two terminals shown in FIG. 5C, and the secondary battery 300 is charged. As the battery 300 is charged, the potential difference between the electrodes increases.

[0254] [Cylindrical secondary battery] Next, an example of a cylindrical secondary battery will be described with reference to FIG. 6. Cylindrical secondary battery 600 6A shows an external view of the cylindrical secondary battery 600. FIG. 6B is a schematic cross-sectional view of the cylindrical secondary battery 600. As shown in FIG. 6B, the cylindrical secondary battery 600 has a positive electrode cap (battery cover) on the top surface. The positive electrode cap has a positive electrode cap 601, and a battery can (external can) 602 on the side and bottom. The cap and the battery can (external can) 602 are insulated by a gasket (insulating packing) 610. It has been done.

[0255] Inside the hollow cylindrical battery can 602, a strip-shaped positive electrode 604 and a negative electrode 606 are placed with a separator. The battery element is wound with the battery 605 sandwiched between them. The battery can 602 is closed at one end and open at the other. The battery can 602 is made of nickel, aluminum, or titanium, which is resistant to corrosion by the electrolyte. or alloys of these with other metals (e.g., stainless steel, etc.) In addition, nickel, aluminum, etc. can be used to prevent corrosion by the electrolyte. It is preferable to coat the battery can 602. Inside the battery can 602, the positive electrode, the negative electrode, and The battery element, in which the separator and the battery cell are wound, is sandwiched between a pair of opposing insulating plates 608 and 609. The inside of the battery can 602 in which the battery element is provided is filled with a non-aqueous electrolyte (not shown). The non-aqueous electrolyte can be the same as that used in coin-type secondary batteries. do.

[0256] The positive and negative electrodes used in cylindrical storage batteries are wound, so active material is formed on both sides of the current collector. A positive electrode terminal (positive electrode current collecting lead) 603 is connected to the positive electrode 604, and a negative A negative electrode terminal (negative electrode current collecting lead) 607 is connected to the positive electrode 603. The positive electrode terminal 607 can be made of a metal material such as aluminum. 603 is resistance-welded to the safety valve mechanism 612, and the negative terminal 607 is resistance-welded to the bottom of the battery can 602. The safety valve mechanism 612 is a PTC (Positive Temperature Coupling) It is electrically connected to the positive electrode cap 601 via an effective element 611 . The safety valve mechanism 612 releases the positive electrode cap 601 when the internal pressure of the battery exceeds a predetermined threshold. The PTC element 611 cuts off the electrical connection between the positive electrode 604 and the positive electrode 604. It is a thermal resistor whose resistance increases when the temperature rises, and the increase in resistance limits the amount of current. It prevents abnormal heat generation. The PTC element is made of barium titanate (BaTiO3) Semiconductor ceramics and the like can be used.

[0257] 6C, a plurality of secondary batteries 600 are disposed between conductive plates 613 and 614. The secondary batteries 600 may be sandwiched between the secondary batteries 600 to form a module 615. They may be connected in series or in parallel and then in series. By configuring a module 615 having a plurality of secondary batteries 600, a large It is possible to extract sufficient power.

[0258] 6D is a top view of module 615. Conductive plate 613 is shown with dashed lines for clarity. As shown in FIG. 6D, a module 615 electrically connects a plurality of secondary batteries 600. A conductive plate may be provided over the conductive wire 616. Furthermore, a temperature control device 617 may be provided between the plurality of secondary batteries 600. When the secondary battery 600 is overheated, it is cooled by the temperature control device 617. If it is too hot, it can be heated by the temperature control device 617. The performance of 615 is less affected by the outside temperature. It is preferable that the material is non-flammable and non-combustible.

[0259] By using the positive electrode active material described in the above embodiment for the positive electrode 604, high capacity and cycle The cylindrical secondary battery 600 can be made to have excellent battery characteristics.

[0260] [Example of secondary battery structure] Another structural example of the secondary battery will be described with reference to FIGS.

[0261] 7A and 7B are diagrams showing the appearance of the battery pack. 00 and a secondary battery 913. A label 910 is attached to the secondary battery 913. Furthermore, as shown in FIG. 7B, the secondary battery 913 has a terminal 951 and a terminal 952. The circuit board 900 is also fixed with a seal 915 .

[0262] The circuit board 900 has a terminal 911 and a circuit 912. The terminal 911 is 900 is connected to a terminal 951, a terminal 952, an antenna 914, and a circuit 912. In addition, a plurality of terminals 911 are provided, and each of the plurality of terminals 911 is used as a control signal input terminal. , a power supply terminal, etc.

[0263] The circuit 912 may be provided on the back surface of the circuit board 900. The shape of the antenna is not limited to a coil, but may be, for example, a wire or a plate. Antennas such as face antennas, traveling wave antennas, EH antennas, magnetic field antennas, and dielectric antennas Alternatively, the antenna 914 may be a flat conductor. The body can function as one of the conductors for electric field coupling. The antenna 914 may function as one of the two conductors. This means that power can be exchanged not only through electromagnetic fields and magnetic fields, but also through electric fields.

[0264] The battery pack has a layer 916 between the antenna 914 and the secondary battery 913. Layer 916 has a function of shielding an electromagnetic field generated by, for example, a secondary battery 913. For example, a magnetic material can be used as 6.

[0265] The structure of the secondary battery is not limited to that shown in FIG.

[0266] For example, as shown in FIGS. 8A and 8B, the secondary battery 913 shown in FIGS. 7A and 7B That is, an antenna may be provided on each of a pair of opposing surfaces. 8A is an external view showing one of the pair of surfaces, and FIG. 8B is an external view showing the other of the pair of surfaces. 7A and 7B, the same parts as those of the secondary battery shown in FIG. 7A and 7B are the same as those of the secondary battery shown in FIG. The description of the battery can be used as appropriate.

[0267] As shown in FIG. 8A, a layer 916 is sandwiched between one of the two surfaces of a secondary battery 913 and an antenna 9 8B, a layer 917 is sandwiched between the other of the pair of surfaces of the secondary battery 913. The layer 917 is provided with an antenna 918. The layer 917 is used to shield the electromagnetic field generated by the secondary battery 913, for example. The layer 917 has a function of shielding the film. For example, a magnetic material can be used. do.

[0268] By adopting the above structure, the size of both the antenna 914 and the antenna 918 can be increased. The antenna 918 can perform data communication with an external device, for example. The antenna 918 has a function of being able to receive the signal. A method for communication between a secondary battery and other devices via an antenna 918 can be applied. The method is to use NFC (near field communication) between secondary batteries and other devices. It is possible to apply a response method that can be used.

[0269] Alternatively, as shown in FIG. 8C, a display device 920 may be connected to the secondary battery 913 shown in FIGS. 7A and 7B. The display device 920 is electrically connected to the terminal 911. The label 910 may not be provided in the portion where the label 920 is provided. 7A and 7B are used as appropriate for the same parts as those of the secondary battery shown in FIG. can.

[0270] The display device 920 displays, for example, an image indicating whether charging is in progress or not, an image indicating the amount of stored power, etc. The display device 920 may be, for example, an electronic paper, a liquid crystal display, an electronic For example, an electroluminescence (EL) display device can be used. By using the polarizer, the power consumption of the display device 920 can be reduced.

[0271] Alternatively, as shown in FIG. 8D, a sensor 921 may be attached to the secondary battery 913 shown in FIGS. 7A and 7B. The sensor 921 is electrically connected to the terminal 911 via the terminal 922. Note that the same parts as those of the secondary battery shown in FIGS. 7A and 7B are shown in FIGS. The description of the secondary battery can be used as appropriate.

[0272] The sensor 921 may be, for example, a sensor for measuring displacement, position, velocity, acceleration, angular velocity, number of rotations, distance, Light, liquid, magnetism, temperature, chemical substances, sound, time, hardness, electric field, current, voltage, power, radiation, It is sufficient if it has the function of measuring flow rate, humidity, gradient, vibration, odor, or infrared. By providing the sensor 921, for example, data indicating the environment in which the secondary battery is placed can be obtained. It is also possible to detect data (such as temperature) and store it in memory within the circuit 912.

[0273] Furthermore, an example of the structure of the secondary battery 913 will be described with reference to FIGS.

[0274] The secondary battery 913 shown in FIG. 9A has terminals 951 and 952 provided inside the housing 930. The battery has a wound body 950. The wound body 950 is impregnated with an electrolyte inside the housing 930. The terminal 952 is in contact with the housing 930, and the terminal 951 is in contact with the housing 930 by using an insulating material or the like. 9A, for the sake of convenience, the housing 930 is not in contact with the housing 930. However, in reality, the winding body 950 is covered by the housing 930, and the terminals 951 and 952 are The housing 930 may be made of a metal material (for example, aluminum) or A resin material can be used.

[0275] As shown in FIG. 9B, the housing 930 shown in FIG. 9A may be formed from a plurality of materials. For example, a secondary battery 913 shown in FIG. 9B is made by bonding a housing 930a and a housing 930b together. A wound body 950 is provided in the area surrounded by the housing 930a and the housing 930b. There are.

[0276] The housing 930a can be made of an insulating material such as organic resin. By using a material such as organic resin on the surface on which the capacitor is formed, the electric field generated by the secondary battery 913 If the shielding of the electric field by the housing 930a is small, the housing 930a An antenna such as antenna 914 may be provided inside the housing 930b. A metallic material can be used.

[0277] Furthermore, the structure of the wound body 950 is shown in FIG. 10. The wound body 950 includes a negative electrode 931 and The wound body 950 has a positive electrode 932 and a separator 933. The wound body 950 has the separator 933 sandwiched therebetween. Then, the negative electrode 931 and the positive electrode 932 are stacked one on top of the other, and the laminated sheet is wound. The negative electrode 931, the positive electrode 932, and the separator 933 may be further laminated. Multiple layers may be stacked.

[0278] The negative electrode 931 is connected to the terminal 911 shown in FIG. 7 via one of the terminals 951 and 952. The positive electrode 932 is connected to the terminal 911 shown in FIG. 7 via the other of the terminals 951 and 952. is connected to.

[0279] By using the positive electrode active material described in the above embodiment for the positive electrode 932, a high capacity and cycle life can be achieved. This makes it possible to obtain a secondary battery 913 with excellent battery characteristics.

[0280] [Laminated secondary battery] Next, an example of a laminated secondary battery will be described with reference to FIGS. If the laminated secondary battery is made flexible, it can be made with fewer flexible parts. If the secondary battery is mounted in an electronic device that has some of the same characteristics, the secondary battery can be bent in accordance with the deformation of the electronic device. It is also possible.

[0281] A laminated secondary battery 980 will be described with reference to FIG. The secondary battery 980 has a wound body 993 shown in FIG. 11A. The wound body 993 has a negative electrode 994 and 10. The wound body 993 has a positive electrode 995 and a separator 996. As with the case 950, a negative electrode 994 and a positive electrode 995 are stacked with a separator 996 sandwiched therebetween. The laminated sheet is then wound up.

[0282] The number of layers of the negative electrode 994, the positive electrode 995, and the separator 996 may be as many as necessary. The negative electrode 994 is connected to the lead electrode 997 and the lead electrode 998. The positive electrode 995 is connected to a negative electrode current collector (not shown) via one of the lead electrodes 998. The positive electrode 997 is connected to a positive electrode current collector (not shown) via the other of the electrode 997 and the lead electrode 998. .

[0283] As shown in FIG. 11B, a film 981 serving as an exterior body and a film 982 having a recess are provided. The above-mentioned wound body 993 is housed in a space formed by bonding the above-mentioned wound body 993 together by thermocompression bonding or the like. 11C, a secondary battery 980 can be fabricated. The lead electrode 997 and the lead electrode 998 are provided. The film 981 and the film 982 are provided with a recess. The interior of the glass 982 is impregnated with an electrolyte.

[0284] The film 981 and the film 982 having the recesses are made of a metal material such as aluminum. The film 981 and the film 982 having the recesses can be made of a metal or resin material. If a resin material is used as the material for the recess, when an external force is applied, the film 981 and the recess The film 982 having the above structure can be deformed to produce a flexible storage battery. can be done.

[0285] Although two films are used in FIGS. 11B and 11C, one film may be used. A space is formed by folding the film, and the above-mentioned wound body 993 is accommodated in the space. You may also pay.

[0286] By using the positive electrode active material described in the previous embodiment for the positive electrode 995, it is possible to achieve high capacity and cycle. The secondary battery 980 can have excellent battery characteristics.

[0287] In addition, in FIG. 11, a secondary battery having a wound body in a space formed by a film that serves as an exterior body is shown. We have explained the example of 980, but as shown in Figure 12, the shape is determined by the film that forms the exterior. It can also be used as a secondary battery having a plurality of rectangular positive electrodes, separators, and negative electrodes in the space formed. good.

[0288] The laminated secondary battery 500 shown in FIG. 12A includes a positive electrode current collector 501 and a positive electrode active material a positive electrode 503 having a layer 502, and a negative electrode having a negative electrode current collector 504 and a negative electrode active material layer 505. The battery includes an electrode 506, a separator 507, an electrolyte 508, and an exterior body 509. A separator 507 is provided between a positive electrode 503 and a negative electrode 506 provided in a battery 509. The exterior body 509 is filled with an electrolyte 508. The electrolyte solution shown in Form 2 can be used.

[0289] In the laminated secondary battery 500 shown in FIG. 12A, a positive electrode current collector 501 and a negative electrode The current collector 504 also serves as a terminal for electrical contact with the outside. The current collector 501 and the negative electrode current collector 504 are arranged so as to be partially exposed to the outside from the exterior body 509. In addition, the positive electrode current collector 501 and the negative electrode current collector 504 may be disposed outside the outer casing 509. The lead electrode is not exposed to the positive electrode current collector 501 or the negative electrode current collector 502. The lead electrode may be exposed to the outside by ultrasonic bonding to the electric body 504 .

[0290] In the laminated secondary battery 500, the exterior body 509 is made of, for example, polyethylene, polypropylene, or the like. On a membrane made of a material such as polypropylene, polycarbonate, ionomer, or polyamide, A thin metal film with excellent flexibility, such as aluminum, stainless steel, copper, or nickel, is applied. On the metal thin film, an insulating composite such as polyamide resin or polyester resin is used as the outer surface of the exterior body. A laminate film having a three-layer structure provided with a resin film can be used.

[0291] An example of the cross-sectional structure of a laminated secondary battery 500 is shown in FIG. For simplicity, an example consisting of two current collectors is shown in Fig. 12B. It is composed of multiple electrode layers.

[0292] In FIG. 12B, as an example, the number of electrode layers is set to 16. In FIG. 12B, the negative electrode current collector 504 has eight layers and the positive electrode current collector The structure shown is 16 layers in total, with 8 layers of the conductive material 501. The cross section shows eight layers of negative electrode current collectors 504 that are ultrasonically bonded together. The number is not limited to 16, and may be more or less. In addition, when the number of electrode layers is small, the secondary battery can be thin. This allows the secondary battery to be molded and has excellent flexibility.

[0293] An example of an external view of a laminated secondary battery 500 is shown in FIGS. 13 and 14. 13 and 14 show a positive electrode 503, a negative electrode 506, a separator 507, an outer casing 509, a positive electrode lead The positive electrode 510 and the negative electrode 511 are provided.

[0294] 15A shows an external view of the positive electrode 503 and the negative electrode 506. The positive electrode 503 is a positive electrode current collector 501. The positive electrode active material layer 502 is formed on the surface of the positive electrode current collector 501. The negative electrode 503 has a region where the positive electrode current collector 501 is partially exposed (hereinafter referred to as the tab region). 06 has a negative electrode current collector 504, and a negative electrode active material layer 505 is formed on the surface of the negative electrode current collector 504. The negative electrode 506 has a region where the negative electrode current collector 504 is partially exposed, i.e., a tab region. The area and shape of the tab regions of the positive electrode and negative electrode are not limited to the example shown in FIG. 15A. stomach.

[0295] [Method for manufacturing laminated secondary batteries] Here, an example of a method for manufacturing a laminated secondary battery, the external view of which is shown in FIG. 13, will be described with reference to FIG. 5B and 15C.

[0296] First, the negative electrode 506, the separator 507, and the positive electrode 503 are stacked. The negative electrode 506, separator 507, and positive electrode 503 are shown. Here, five pairs of negative electrodes and four pairs of positive electrodes are shown. Next, the bonding of the tab regions of the positive electrode 503 and the bonding of the tab region of the positive electrode on the outermost surface are shown. The positive electrode lead electrode 510 is joined to the electrode region 510. For example, ultrasonic welding or the like may be used for joining. Similarly, the tab regions of the negative electrodes 506 are joined together, and the negative electrode leads to the tab regions of the negative electrodes on the outermost surface are Then, the electrode 511 is bonded.

[0297] Next, the negative electrode 506 , the separator 507 and the positive electrode 503 are placed on the exterior body 509 .

[0298] Next, as shown in Fig. 15C, exterior body 509 is folded at the portion indicated by the dashed line. The outer periphery of the exterior body 509 is bonded. For example, thermocompression bonding may be used for bonding. The electrode is connected to a part (or one side) of the exterior body 509 so that the electrolyte 508 can be poured in later. An area where the two components are not mixed (hereinafter referred to as an inlet) is provided.

[0299] Next, electrolyte 508 (not shown) is introduced into the exterior body 509 through an inlet provided in the exterior body. The electrolyte solution 508 is introduced into the inside of the electrode 509 under a reduced pressure atmosphere or an inert atmosphere. Finally, the inlet is bonded. A secondary battery 500 of this type can be fabricated.

[0300] By using the positive electrode active material described in the previous embodiment for the positive electrode 503, it is possible to achieve high capacity and cycle. The secondary battery 500 can have excellent battery characteristics.

[0301] [Bendable secondary battery] Next, an example of a bendable secondary battery will be described with reference to FIGS. 16 and 17. do.

[0302] 16A shows a schematic top view of a bendable secondary battery 250. 16C and 16D are cut along the lines C1-C2, C3-C4, and C5 in FIG. 16A, respectively. A secondary battery 250 is a schematic cross-sectional view taken along the line A1-A2. The electrode stack 210 includes at least a positive electrode The positive electrode 211a and the negative electrode 211b are electrically connected to the lead 212. a and the lead 212b electrically connected to the negative electrode 211b are attached to the outside of the exterior body 251. In addition, in the area surrounded by the exterior body 251, the positive electrode 211a and the negative electrode 211b are In addition, an electrolyte (not shown) is enclosed.

[0303] The positive electrode 211a and the negative electrode 211b of the secondary battery 250 will be explained with reference to FIG. FIG. 17A illustrates the stacking order of the positive electrode 211a, the negative electrode 211b, and the separator 214. FIG. 17B is a perspective view illustrating the structure of the lead 211 in addition to the positive electrode 211a and the negative electrode 211b. 2a and lead 212b.

[0304] As shown in FIG. 17A, the secondary battery 250 includes a plurality of rectangular positive electrodes 211a, a plurality of rectangular positive electrodes 211b, a plurality of rectangular positive electrodes 211c, a plurality of rectangular positive electrodes 211d, a plurality of rectangular positive electrodes 211e, a plurality of rectangular positive electrodes 211f, a plurality of rectangular positive electrodes 211g, a plurality of rectangular positive electrodes 211h ... The positive electrode 211a and the negative electrode 211b have a rectangular shape and a plurality of separators 214. 1b each have a protruding tab portion and a portion other than the tab. A positive electrode active material layer is formed on the portion other than the tab of the negative electrode 211b. A negative electrode active material layer is formed on the negative electrode.

[0305] The surfaces of the positive electrodes 211a on which the positive electrode active material layer is not formed and the surfaces of the negative electrodes 211b on which the negative electrode active material layer is not formed are The positive electrode 211a and the negative electrode 211b are stacked so that the surfaces on which no material layer is formed are in contact with each other. It is layered.

[0306] In addition, the surface of the positive electrode 211a on which the positive electrode active material layer is formed and the surface of the negative electrode 211b on which the negative electrode active material layer is formed are A separator 214 is provided between the formed surfaces. The parameter 214 is shown in dotted lines.

[0307] As shown in FIG. 17B, the positive electrodes 211a and the leads 212a are connected to each other at the joints 215a. The negative electrodes 211b and the leads 212b are electrically connected at the joints 21 5b are electrically connected.

[0308] Next, the exterior body 251 will be described with reference to FIGS. 16B, 16C, 16D, and 16E. do.

[0309] The exterior body 251 has a film-like shape and is configured to sandwich the positive electrode 211a and the negative electrode 211b. The exterior body 251 is folded in two as shown in FIG. The pair of sealing portions 262 are connected to the positive electrode 211a and the sealing portion 263. The seal portion 2 is provided on either side of the negative electrode 211b and can also be called a side seal. 63 has a portion overlapping with the lead 212a and the lead 212b, and is also called a top seal. It is possible.

[0310] The exterior body 251 has ridge lines 271 and valley lines at the portions overlapping the positive electrode 211a and the negative electrode 211b. It is preferable that the sealing portion 272 of the exterior body 251 has a wave shape in which the sealing portions 272 are arranged alternately. 62 and the seal portion 263 are preferably flat.

[0311] FIG. 16B is a cross section cut at the portion overlapping with the ridge line 271, and FIG. 16C is a cross section cut at the portion overlapping with the valley line 272. 16B and 16C are cross sections cut at the overlapping portion of the secondary battery 250 and the positive electrode 252. 1 corresponds to a cross section in the width direction of the anode 211a and the cathode 211b.

[0312] Here, the widthwise ends of the positive electrode 211a and the negative electrode 211b, i.e., the positive electrode 211a and the negative electrode 211b, The distance between the end of the negative electrode 211b and the seal portion 262 is defined as La. When deformation such as bending is applied to the positive electrode 211a and the negative electrode 211b, as will be described later, If the distance La is too short, the outer casing 251 The positive electrode 211a and the negative electrode 211b may rub strongly against each other, and the exterior body 251 may be damaged. In particular, if the metal film of the exterior body 251 is exposed, the metal film may be easily damaged by the electrolyte. Therefore, it is preferable to set the distance La as long as possible. On the other hand, if the distance La is made too large, the volume of the secondary battery 250 increases. .

[0313] In addition, the greater the total thickness of the stacked positive electrode 211a and negative electrode 211b, the greater the It is preferable to increase the distance La between the negative electrode 211a and the seal portion 262. stomach.

[0314] More specifically, the stacked positive electrode 211a, negative electrode 211b, and separator (not shown) When the total thickness of the actuator 214 is t, the distance La is 0.8 to 3.0 times the thickness t. Preferably, the ratio is 0.9 to 2.5 times, more preferably 1.0 to 2.0 times. By setting the distance La in this range, it is possible to make the device compact and resistant to bending. This makes it possible to realize a highly reliable battery.

[0315] Furthermore, when the distance between the pair of seal portions 262 is a distance Lb, the distance Lb is a and the width of the negative electrode 211b (here, the width Wb of the negative electrode 211b). This is preferable because it prevents the secondary battery 250 from being deformed by repeated bending or other deformation. Even if the positive electrode 211a and the negative electrode 211b come into contact with the exterior body 251, Since a part of the negative electrode 211b can be shifted in the width direction, the positive electrode 211a and the negative electrode 211 This effectively prevents the outer casing 251 from rubbing against the outer casing 251.

[0316] For example, the difference between the distance Lb between the pair of seal portions 262 and the width Wb of the negative electrode 211b is The thickness is 1.6 times or more and 6.0 times or less, preferably 1.8 times or more, the thickness t of the positive electrode 211a and the negative electrode 211b. It is preferable that the ratio is 2.0 times or more and 5.0 times or less, and more preferably 2.0 times or more and 4.0 times or less. stomach.

[0317] FIG. 16D is a cross section including the lead 212a, and shows the secondary battery 250, the positive electrode 211a, and 16D, the bent portion 26 corresponds to the cross section of the negative electrode 211b in the longitudinal direction. 1, between the ends of the positive electrode 211a and the negative electrode 211b in the length direction and the exterior body 251 It is preferable to have a space 273 therebetween.

[0318] FIG. 16E shows a schematic cross-sectional view of the secondary battery 250 when bent. This corresponds to the cross section taken along the line B1-B2 in FIG. 16A.

[0319] When the secondary battery 250 is bent, a part of the exterior body 251 located on the outside of the bend stretches, and More specifically, the other part located on the outside of the exterior body 251 is deformed so as to shrink. The part where the wave is generated is deformed so that the amplitude of the wave is small and the period of the wave is large. The part located inside 251 changes so that the wave amplitude is large and the wave period is small. In this way, the exterior body 251 is deformed, and as it is bent, Since this stress is alleviated, the material that constitutes exterior body 251 itself does not need to expand or contract. As a result, the exterior body 251 is not damaged and the secondary battery 250 can be bent with a small force. can.

[0320] Furthermore, as shown in FIG. 16E, when the secondary battery 250 is bent, the positive electrode 211a and the negative electrode 211b are bent. At this time, the plurality of stacked positive electrodes 211a and negative electrodes 11b are displaced relative to each other. The pole 211b is fixed at one end on the seal portion 263 side by the fixing member 217, so that the pole 211b is not bent. The amount of deviation increases as the distance approaches the edge 261. The stress applied to the positive electrode 211a and the negative electrode 211b is relieved, and the positive electrode 211a and the negative electrode 211b themselves As a result, the positive electrode 211a and the negative electrode 211b are not damaged. The secondary battery 250 can be easily bent.

[0321] In addition, a space 273 is provided between the positive electrode 211a and the negative electrode 211b and the exterior body 251. By this, the positive electrode 211a and the negative electrode 211b located on the inner side when bent are attached to the exterior body 25. It can move relative to 1 without touching it.

[0322] The secondary battery 250 illustrated in FIGS. 16 and 17 has a good external appearance even when repeatedly bent and stretched. Damage to the housing, the positive electrode 211a and the negative electrode 211b, etc., is unlikely to occur, and the battery characteristics are also unlikely to deteriorate. The secondary battery 250 has a positive electrode 211a that is not easily broken down. By using such a positive electrode active material, a battery with even better cycle characteristics can be obtained.

[0323] (Fourth embodiment) In this embodiment, an example in which a secondary battery according to one embodiment of the present invention is mounted in an electronic device will be described. Reveal.

[0324] First, as explained in part of the third embodiment, a bendable secondary battery is mounted on an electronic device. Examples of such a device are shown in Figures 18A to 18G. For example, television equipment (also called television or television receiver), computers, Computer monitors, digital cameras, digital video cameras, digital photo frames systems, mobile phones (also called mobile phones or mobile phone devices), portable game machines, personal digital assistants, Examples include audio playback devices and large game machines such as pachinko machines.

[0325] In addition, the flexible secondary battery can be attached to the inner or outer wall of a house or building, or to an automobile. It can also be incorporated into curved surfaces of the interior or exterior of a vehicle.

[0326] FIG. 18A shows an example of a mobile phone. A mobile phone 7400 is provided in a housing 7401. In addition to the built-in display unit 7402, operation buttons 7403, external connection port 7404, The mobile phone 7400 is equipped with a speaker 7405, a microphone 7406, etc. The secondary battery 7407 is a secondary battery according to one embodiment of the present invention. This makes it possible to provide a lightweight mobile phone with a long lifespan.

[0327] FIG. 18B shows the mobile phone 7400 in a bent state. When the battery is deformed by an external force and curved, the secondary battery 7 disposed inside the battery The secondary battery 7407 is also bent. At this time, the state of the bent secondary battery 7407 is shown in FIG. 18C. The secondary battery 7407 is a thin storage battery. The secondary battery 7407 is fixed in a bent state. The secondary battery 7407 has a lead electrode electrically connected to the current collector. For example, the current collector is made of copper foil, and some of it is alloyed with gallium to form an active material in contact with the current collector. This improves adhesion with the polymer layer, resulting in a highly reliable configuration even when the secondary battery 7407 is bent. It is.

[0328] FIG. 18D shows an example of a bangle-type display device. The portable display device 7100 is The device includes a body 7101, a display unit 7102, operation buttons 7103, and a secondary battery 7104. FIG. 18E shows the bent state of the secondary battery 7104. When the device is worn on the user's arm with the case closed, the case may deform and cause a part or all of the secondary battery 7104 to break. The curvature changes. The degree of curvature at any point on the curve is expressed by the value of the radius of the corresponding circle. The radius of curvature is called the radius of curvature, and the reciprocal of the radius of curvature is called the curvature. Part or all of the main surface of the casing or secondary battery 7104 within the range of 150 mm or more The radius of curvature of the main surface of the secondary battery 7104 is 40 mm or more and 150 mm or less. High reliability can be maintained within the range below. By using such a secondary battery, a lightweight, long-life portable display device can be provided.

[0329] FIG. 18F shows an example of a wristwatch-type mobile information terminal. The mobile information terminal 7200 includes: Housing 7201, display unit 7202, band 7203, buckle 7204, operation button 720 5, and has an input / output terminal 7206, etc.

[0330] The portable information terminal 7200 is capable of performing functions such as mobile phone calls, e-mails, document browsing and creation, music playback, internet connection, and so on. It can run various applications such as internet communication and computer games. Cut.

[0331] The display surface of the display unit 7202 is curved, and the display is performed along the curved display surface. The display portion 7202 is provided with a touch sensor, and the screen can be touched with a finger or a stylus. For example, the icon 7 displayed on the display unit 7202 can be operated by touching the You can launch the application by touching 207.

[0332] The operation button 7205 is used to set the time, turn the power on and off, and turn wireless communication on and off. It has various functions such as auto-start, silent mode activation and deactivation, power saving mode activation and deactivation, etc. For example, an operating system built into the mobile information terminal 7200 can be The system also allows the functions of the operation buttons 7205 to be freely set.

[0333] In addition, the mobile information terminal 7200 is capable of performing standardized short-range wireless communication. For example, by communicating with a wireless headset, hands-free You can also make calls.

[0334] The portable information terminal 7200 also has an input / output terminal 7206, and can be connected to other information terminals via a connector. Data can be exchanged directly through the input / output terminal 7206. The charging operation can be performed by wireless power supply without going through the input / output terminal 7206. You may go.

[0335] The display portion 7202 of the portable information terminal 7200 includes the secondary battery of one embodiment of the present invention. By using the secondary battery of one embodiment of the present invention, a lightweight and long-life portable information terminal can be provided. For example, the secondary battery 7104 shown in FIG. 18E is curved and inserted into the housing 7201. , or may be incorporated into the band 7203 in a bendable state.

[0336] The mobile information terminal 7200 preferably has a sensor. For example, a fingerprint sensor may be used as the sensor. Human body sensors such as sensors, pulse sensors, and body temperature sensors, as well as touch sensors, pressure sensors, and acceleration sensors It is preferable that a sensor, etc. be installed.

[0337] FIG. 18G shows an example of a wristband-type display device. The display device 7300 includes a display unit 73 04 and includes the secondary battery of one embodiment of the present invention. The unit 7304 may be provided with a touch sensor, and may function as a mobile information terminal. It can also be done as follows.

[0338] The display surface of the display unit 7304 is curved, and images are displayed along the curved display surface. The display device 7300 can also communicate with the display device 7300 by short-distance wireless communication according to a communication standard. You can change the situation.

[0339] The display device 7300 is also equipped with an input / output terminal, and can be directly connected to other information terminals via a connector. It is possible to exchange data and also charge via the input / output terminal. The charging operation may be performed by wireless power supply without using the input / output terminals.

[0340] When the secondary battery of one embodiment of the present invention is used as the secondary battery included in the display device 7300, A lightweight, long-life display device can be provided.

[0341] In addition, an example in which the secondary battery with good cycle characteristics shown in the above embodiment is mounted on an electronic device will be described. This will be explained using Figures 18H, 19 and 20.

[0342] By using the secondary battery of one embodiment of the present invention as a secondary battery in everyday electronic devices, it is possible to achieve lighter weight and a longer life. For example, we can provide daily electronic products such as electric toothbrushes, electric shavers, Examples include electric beauty devices, and the secondary batteries for these products are designed to be easy for users to hold. Therefore, there is a demand for a secondary battery that is stick-shaped, small, lightweight, and has a large capacity.

[0343] FIG. 18H is a perspective view of a device also known as a tobacco-containing smoking device (electronic cigarette). The electronic cigarette 7500 in 8H includes an atomizer 7501 containing a heating element; a secondary battery 7504 for supplying power to the cartridge including a liquid supply bottle, a sensor, etc. To enhance safety, the secondary battery 7504 is designed to prevent overcharging and over-discharging. A protection circuit for preventing the secondary battery 7504 from being damaged may be electrically connected to the secondary battery 7504. The secondary battery 7504 has an external terminal so that it can be connected to a charging device. Since this becomes the tip when the device is used, it is desirable that the total length is short and the weight is light. The secondary battery according to one embodiment of the present invention has a high capacity and good cycle characteristics, and therefore can be used for a long period of time. This allows us to provide a small and lightweight electronic cigarette 7500 that can be used for long periods of time.

[0344] Next, an example of a foldable tablet terminal is shown in FIGS. 19A and 19B. The tablet terminal 9600 shown in FIGS. 19A and 19B includes a housing 9630a, a housing 963 0b, a movable part 9640 connecting the housing 9630a and the housing 9630b, a display part 9631a, and A display unit 9631 having a display unit 9631b, a switch 9625, a switch 9626, and It has a switch 9627, a fastener 9629, and an operation switch 9628. By using a flexible panel, it is possible to create a tablet terminal with a larger display area. FIG. 19A shows a tablet terminal 9600 in an open state, and FIG. B shows the tablet terminal 9600 in a closed state.

[0345] The tablet terminal 9600 also includes a housing 9630a and a housing 9630b. The power storage unit 9635 is connected to the housing 9630a through a movable part 9640. It is provided across the body 9630b.

[0346] The entire or a part of the display portion 9631 can be used as a touch panel. By touching images, text, input forms, etc. containing icons displayed in the area, data can be For example, the entire surface of the display portion 9631a on the housing 9630a side is covered with keys. The board buttons are displayed, and information such as characters and images is displayed on the display unit 9631b on the housing 9630b side. The information may be displayed.

[0347] In addition, a keyboard is displayed on the display unit 9631b on the housing 9630b side. The display unit 9631a on the a side may be used to display information such as characters and images. The keyboard display switch button of the touch panel is displayed in the section 9631. Touching the buttons with your finger or a stylus will display a keyboard on the display 9631. It can also be set to

[0348] In addition, the touch panel area of ​​the display unit 9631a on the housing 9630a side and the touch panel area of ​​the display unit 9631b on the housing 9630b side are It is also possible to simultaneously perform touch inputs to the touch panel area of ​​the display portion 9631b.

[0349] In addition, switches 9625 to 9627 are used to operate the tablet terminal 9600. It is not only an interface for switching between various functions, but also an interface for For example, at least one of the switches 9625 to 9627 may be an interface. The other functions as a power on / off switch for the tablet device 9600. Also, for example, at least one of the switches 9625 to 9627 may The ability to switch between portrait and landscape display, or between black and white and color display For example, at least one of the switches 9625 to 9627 may have a function of switching the At least one of the display units 9631 may have a function to adjust the brightness of the display unit 9631. The brightness of 31 is the brightness detected by the light sensor built into the tablet terminal 9600 during use. It can be optimized according to the amount of external light. In addition, other detection devices such as gyro, acceleration sensor, etc. that detect tilt are also included. It may be stored.

[0350] In addition, in FIG. 19A, the display unit 9631a on the housing 9630a side and the display unit 9631b on the housing 9630b side are 9631b has almost the same display area, The display area of ​​each of the display areas 31b is not particularly limited, and the size of one is different from the size of the other. For example, one may have a higher resolution display than the other. It may also be a display panel that can perform this function.

[0351] FIG. 19B shows the tablet terminal 9600 in a folded state. The terminal 9600 includes a housing 9630, a solar cell 9633, and a DC-DC converter 9636. A charge / discharge control circuit 9634 is also provided. Use a storage battery.

[0352] As mentioned above, the tablet terminal 9600 can be folded in half, so when not in use, The housing 9630a and the housing 9630b can be folded together. By folding the tablet terminal 9600, the display portion 9631 can be protected. Furthermore, the power storage unit 9635 using the secondary battery of one embodiment of the present invention can With its high capacity and good cycle characteristics, this tablet can be used for a long period of time. A mobile terminal 9600 can be provided.

[0353] In addition, the tablet terminal 9600 shown in FIGS. 19A and 19B can be used in various Functions that display important information (still images, videos, text images, etc.), calendars, dates, or times The function to display the information on the display unit, and the function to touch input or edit the information displayed on the display unit. It has functions such as inputting characters, controlling processes using various software (programs), etc. It is possible.

[0354] The tablet terminal 9600 is equipped with a solar cell 9633 on its surface, which generates power. The solar cell 96 can supply the power to the panel, the display unit, the video signal processing unit, etc. 33 can be provided on one or both sides of the housing 9630, and can efficiently charge the power storage unit 9635. The power storage unit 9635 can be configured to use a lithium ion battery. The use of such a device has the advantage of enabling miniaturization.

[0355] The configuration and operation of the charge / discharge control circuit 9634 shown in FIG. 19B are shown in FIG. 19C. A block diagram is shown and explained. FIG. 19C shows a solar cell 9633, a power storage body 9635, a DCD C Converter 9636, Converter 9637, Switches SW1, SW2 and SW3, Table The display unit 9631 is shown, and the storage battery 9635, the DC-DC converter 9636, 19B. This corresponds to the part.

[0356] First, an example of operation when power is generated by the solar cell 9633 using external light will be described. The power generated by the solar cell is converted into a voltage to charge the storage battery 9635. The converter 9636 increases or decreases the voltage. When power is used from the battery 9633, the switch SW1 is turned on, and the converter 963 7, the voltage is increased or decreased to the voltage required for the display unit 9631. When not displaying in 1, turn SW1 off and SW2 on to turn on the power storage unit 9635. It is sufficient to configure the device so that charging is performed.

[0357] The solar cell 9633 is shown as an example of a power generating means, but is not particularly limited thereto. Storage by other power generation means such as piezoelectric elements and thermoelectric conversion elements (Peltier elements) For example, the power supply 9635 may be configured to transmit and receive power wirelessly (contactlessly). It is also possible to combine it with a contactless power transmission module that charges the battery, or other charging means. You may do so.

[0358] Another example of electronic equipment is shown in FIG. 20. In FIG. 20, a display device 8000 is a display device according to the present invention. 8 is an example of an electronic device using a secondary battery 8004 according to one embodiment. 8000 corresponds to a display device for receiving TV broadcasts, and includes a housing 8001, a display unit 8002, a speaker, and The secondary battery 8004 according to one embodiment of the present invention includes: The display device 8000 is provided inside a housing 8001. The display device 8000 is supplied with power from a commercial power source. It is also possible to use the power stored in the secondary battery 8004. Therefore, even when power cannot be supplied from a commercial power source due to a power outage or the like, the present invention can be used. The display device 8000 can be used by using the secondary battery 8004 as an uninterruptible power supply. become.

[0359] The display unit 8002 is a display device having a light emitting element such as a liquid crystal display device or an organic EL element in each pixel. Optical devices, electrophoretic displays, DMD (Digital Micromirror Devices) ice), PDP (Plasma Display Panel), FED (Field A semiconductor display device such as a reflective LED (emission display) can be used.

[0360] In addition to TV broadcast reception, display devices are also used for personal computers and advertising displays. This includes all display devices for displaying information, such as:

[0361] In FIG. 20, a stationary lighting device 8100 includes a secondary battery 8 according to one embodiment of the present invention. 8103. Specifically, the lighting device 8100 includes a housing 8101, 20, the secondary battery 8103 is disposed in the housing 8. 101 and a light source 8102 are installed inside a ceiling 8104. 8, the secondary battery 8103 may be provided inside the housing 8101. The device 8100 can be supplied with power from a commercial power source or can be powered by a secondary battery 8103. The stored power can also be used. Therefore, in the event of a power outage, the power supply from the commercial power source can be reduced. Even when power is not available, the secondary battery 8103 according to one embodiment of the present invention can be used as an uninterruptible power supply. This allows the lighting device 8100 to be used.

[0362] In addition, FIG. 20 illustrates a lighting device 8100 of a fixed type provided on a ceiling 8104. However, in the secondary battery according to one embodiment of the present invention, in addition to the ceiling 8104, for example, the side wall 8105, the floor It can be used for a fixed lighting device provided in a window 8107 or a desk. It can also be used in upper lighting devices.

[0363] The light source 8102 can be an artificial light source that artificially obtains light using electricity. Specifically, this applies to incandescent lamps, discharge lamps such as fluorescent lamps, and light-emitting devices such as LEDs and organic EL elements. An example of the artificial light source is a light element.

[0364] In FIG. 20, an air conditioner having an indoor unit 8200 and an outdoor unit 8204 is 8 is an example of an electronic device using a secondary battery 8203 of one embodiment of the present invention. The indoor unit 8200 includes a housing 8201, an air outlet 8202, a secondary battery 8203, and the like. In the example shown, the secondary battery 8203 is provided in the indoor unit 8200. The secondary battery 8203 may be provided in the outdoor unit 8204. Both the outdoor units 8204 may be provided with a secondary battery 8203. The battery can be supplied with power from a commercial power source or stored in a secondary battery 8203. In particular, both the indoor unit 8200 and the outdoor unit 8204 are equipped with secondary batteries 8 If 203 is installed, when power cannot be supplied from the commercial power source due to a power outage, etc. However, by using the secondary battery 8203 of one embodiment of the present invention as an uninterruptible power supply, Conditioner can be used.

[0365] In addition, Figure 20 shows a separate type air conditioner consisting of an indoor unit and an outdoor unit. However, it is an integrated air conditioner that has the functions of both an indoor unit and an outdoor unit in a single housing. The secondary battery according to one embodiment of the present invention can also be used for the conditioner.

[0366] In FIG. 20, an electric refrigerator-freezer 8300 includes a secondary battery 8304 according to one embodiment of the present invention. Specifically, an electric refrigerator-freezer 8300 includes a housing 8301, It has a refrigerator door 8302, a freezer door 8303, a secondary battery 8304, etc. A secondary battery 8304 is provided inside the housing 8301. The power can be supplied from a commercial power source or can be stored in a secondary battery 8304. Therefore, when power cannot be supplied from the commercial power source due to a power outage, etc. Even in this case, by using the secondary battery 8304 of one embodiment of the present invention as an uninterruptible power supply, 8300 refrigerators and freezers will be available for use.

[0367] In addition, electronic devices such as microwave ovens and electric rice cookers generate high voltage for a short period of time. Therefore, it is used as an auxiliary power source to supplement the power that cannot be supplied by commercial power. By using the secondary battery according to one embodiment of the present invention, fluctuations in the commercial power supply can be reduced when using an electronic device. This can prevent the car from falling.

[0368] In addition, during times when electronic devices are not in use, the total amount of power that can be supplied by commercial power suppliers is also During the time period when the ratio of the amount of electricity actually used (called the electricity usage rate) is low, By storing power in the secondary battery, it is possible to prevent power usage rates from increasing outside the above time periods. For example, in the case of the electric refrigerator-freezer 8300, when the temperature is low, the refrigerator compartment door 83 02, during the night when the freezer door 8303 is not opened or closed, power is supplied to the secondary battery 8304. Then, as the temperature rises, the refrigerator door 8302 and the freezer door 8303 open and close. During the daytime, when the vehicle is in operation, the secondary battery 8304 is used as an auxiliary power source, thereby reducing the power consumption during the daytime. The rate can be kept low.

[0369] According to one embodiment of the present invention, the cycle characteristics of a secondary battery can be improved, and the reliability can be improved. Furthermore, according to one aspect of the present invention, a high-capacity secondary battery can be obtained. This improves the characteristics of the secondary battery, thereby making the secondary battery itself smaller and lighter. Therefore, the secondary battery according to one embodiment of the present invention can be used in the electronic devices described in this embodiment. By incorporating the technology into the electronic device, it is possible to create an electronic device with a longer lifespan and lighter weight.

[0370] This embodiment mode can be implemented in appropriate combination with other embodiment modes.

[0371] (Embodiment 5) In this embodiment, an example in which a secondary battery according to one embodiment of the present invention is mounted on a vehicle will be described.

[0372] When a secondary battery is installed in a vehicle, it becomes a hybrid vehicle (HEV), an electric vehicle (EV), or It will be possible to realize next-generation clean energy vehicles such as plug-in hybrid vehicles (PHEVs). do.

[0373] FIG. 21A illustrates a vehicle using a secondary battery according to one embodiment of the present invention. The automobile 8400 shown is an electric automobile that uses an electric motor as a power source for driving. Alternatively, an electric motor and an engine can be selected and used as the power source for driving. By using the secondary battery of one embodiment of the present invention, It is possible to realize a vehicle with a long driving range. In addition, the automobile 8400 has a secondary battery. The secondary battery is mounted on the floor of the vehicle using the secondary battery module shown in Figs. 6C and 6D. In addition, a battery pack consisting of multiple secondary batteries as shown in Figure 9 can be used. It may be installed on the floor of the vehicle. The secondary battery only drives the electric motor 8406. 8401 and room lights (not shown) It is possible.

[0374] In addition, the secondary battery is used for the displays of the car 8400, such as the speedometer and tachometer. The secondary battery can supply power to the navigation system of the automobile 8400. The power supply can be used to power semiconductor devices such as gating systems.

[0375] The automobile 8500 shown in FIG. 21B is a plug-in type secondary battery. It can be charged by receiving power from an external charging facility using a wireless power supply system. FIG. 21B shows a diagram of a secondary battery mounted on a vehicle 8500 being charged from a ground-mounted charging device 8021. 8024 shows the state in which charging is being performed via cable 8022. Charging methods and connector standards are specified by CHAdeMO (registered trademark) and Combo. The charging device 8021 may be a charging station installed in a commercial facility. It may also be a household power source. For example, plug-in technology allows the power source to be connected to an external power supply. The secondary battery 8024 and the secondary battery 8025 mounted on the automobile 8500 are charged by the power supply. Charging is performed by converting AC power to DC power via a converter such as an AC-DC converter. It can be converted into a force.

[0376] Although not shown, a power receiving device is mounted on the vehicle, and power is supplied contactlessly from a power transmitting device on the ground. In this case, the power transmission device is installed on the road or on the exterior wall. By incorporating this, charging can be done not only when the vehicle is stopped but also while the vehicle is moving. The vehicle may transmit and receive power between them using the same method. A solar cell may be provided in the vehicle so that the secondary battery can be charged when the vehicle is stopped or running. To supply power in the above, an electromagnetic induction method or a magnetic field resonance method can be used.

[0377] 21C shows an example of a two-wheeled vehicle using the secondary battery of one embodiment of the present invention. The scooter 8600 shown in FIG. 1 includes a secondary battery 8602, a side mirror 8601, a turn signal light 86 03. The secondary battery 8602 can supply electricity to the turn signal light 8603. .

[0378] In addition, the scooter 8600 shown in FIG. 21C has a secondary battery 8602 in the storage space under the seat 8604. The secondary battery 8602 can be stored even if the under-seat storage 8604 is small. It can be stored in the under-seat storage 8604. The secondary battery 8602 is removable. When charging, the secondary battery 8602 is brought indoors, charged, and stored before driving. That's fine.

[0379] According to one aspect of the present invention, the cycle characteristics of the secondary battery are improved, and the capacity of the secondary battery is increased. Therefore, the secondary battery itself can be made smaller and lighter. If the battery itself can be made smaller and lighter, it will contribute to reducing the vehicle's weight, which will improve the cruising range. In addition, the secondary battery installed in the vehicle can be used as a power supply source for other purposes. In this case, for example, it is possible to avoid using commercial power sources during peak power demand periods. If we can avoid using commercial power sources during peak power demand periods, we can save energy and This can contribute to reducing carbon dioxide emissions. Since the secondary battery can be used for a long period of time, the amount of rare metals used, including cobalt, can be reduced. It is possible.

[0380] This embodiment mode can be implemented in appropriate combination with other embodiment modes.

[0381] (Embodiment 6) In this embodiment, a secondary battery including the positive electrode active material of one embodiment of the present invention is mounted. An example of a wearable device is shown below.

[0382] FIG. 22A shows an example of a wearable device. In addition, when the user uses the secondary battery in daily life or outdoors, To improve water resistance, the device can be charged not only via wired charging, but also via an exposed connector. Therefore, there is a demand for wearable devices that can be easily charged wirelessly.

[0383] For example, it can be mounted on a glasses-type device 400 as shown in FIG. The device 400 has a frame 400a and a display unit 400b. By installing a secondary battery in the temple of the 400a, it is lightweight and has good weight balance. Therefore, the eyeglass-type device 400 can be used for a long time.

[0384] It can also be installed in a headset type device 401. The microphone 401 includes at least a microphone part 401a, a flexible pipe 401b, and an earphone. The flexible pipe 401b and the earphone section 401c have a secondary A battery may be provided.

[0385] It can also be mounted on a device 402 that can be attached directly to the body. A secondary battery 402b can be provided inside a thin housing 402a of the device 02.

[0386] It can also be mounted on a device 403 that can be attached to clothing. A secondary battery 403b can be provided inside the thin housing 403a.

[0387] It can also be mounted on a belt-type device 406. The belt-type device 406 includes: It has a belt part 406a and a wireless power receiving part 406b, and inside the belt part 406a A secondary battery can be mounted on the

[0388] It can also be installed in a wristwatch type device 405. The wristwatch type device 405 is The display unit 405a and the belt unit 405b are , a secondary battery may be provided.

[0389] The display unit 405a displays not only the time but also various information such as incoming emails and phone calls. It is possible.

[0390] The wristwatch type device 405 is a wearable device that is worn directly on the wrist. Therefore, sensors for measuring the user's pulse, blood pressure, etc. may be installed. It can also accumulate health-related data and be used to help maintain good health.

[0391] The wristwatch type device 405 shown in FIG. 22A will be described in detail below.

[0392] FIG. 22B shows a perspective view of the wristwatch type device 405 removed from the wrist.

[0393] A side view is shown in Fig. 22C. Fig. 22C shows a device with a built-in secondary battery 913. The secondary battery 913 is provided at a position overlapping the display unit 405a. It is compact and lightweight.

[0394] This embodiment mode can be implemented in appropriate combination with other embodiment modes. [Example]

[0395] In this example, a secondary battery was fabricated using the positive electrode active material of one embodiment of the present invention and evaluated. .

[0396] <Preparation of positive electrode active material> Referring to the production flow shown in Figure 3, the positive electrode active materials Sample 1 and Sample 2 were prepared. Sample 2, Sample 3 and Sample 4 were prepared.

[0397] First, a mixture 902 containing magnesium and fluorine was prepared (steps S11 to S16). Step S14) The molar ratio of LiF and MgF2 was adjusted to LiF:MgF2 = 1:3. The mixture was weighed, and acetone was added as a solvent, followed by wet mixing and grinding. The treatment was carried out in a ball mill using ruthenium balls at 400 rpm for 12 hours. The material was recovered and designated mixture 902.

[0398] Next, nickel hydroxide, which is a metal source, is mixed with acetone to obtain finely powdered nickel hydroxide. A cell was fabricated (steps S15 to S17).

[0399] Next, for Sample 1 and Sample 2, the metal source, aluminum fluoride, was used. Aluminum fluoride was prepared by mixing aluminum with acetone (step Steps S18 to S20). On the other hand, for Sample 3 and Sample 4, In this case, aluminum fluoride is not used as the metal source, but aluminum hydroxide is used instead. Micronized aluminum hydroxide was prepared.

[0400] Next, lithium cobalt oxide was prepared as a composite oxide containing lithium and cobalt. More specifically, Cellseed C-10N manufactured by Nippon Chemical Industry Co., Ltd. was prepared (S Step S25).

[0401] Next, in step S31, the mixture 902, nickel hydroxide, and aluminum fluoride are mixed. Aluminum or aluminum hydroxide was mixed with lithium cobalt oxide. The moles of lithium in Mixture 902 are 0.0033 times the moles of nickel hydroxide. 0.005 times the moles of nickel in Kel, aluminum fluoride or aluminum hydroxide The aluminum mole ratio was 0.005 times that of the aluminum mole ratio ... The mixture was mixed in a ball mill using zirconia balls at 150 rpm for 1 hour. went.

[0402] Next, the processed material was collected to obtain a mixture 903 (steps S32 and S 33).

[0403] Next, the mixture 903 was placed in an aluminum oxide crucible and heated in a muffle furnace in an oxygen atmosphere for 90 Annealing was carried out at 0° C. for 20 hours (step S34).

[0404] The amount of mixture 903 to be annealed was 30 g for Sample 1 and 30 g for Sample 2. Sample 2 was 2.4g, Sample 3 was 30g, and Sample 4 was 2.4g.

[0405] During annealing, the aluminum oxide crucible was covered with a lid. The oxygen flow rate was 10 L / min. The temperature was increased at a rate of 200°C / hr, and the temperature was decreased over a period of 10 hours or more. The material is collected and sieved (step S35), and the positive electrode active material, Sample 1, is obtained. , Sample 2, Sample 3 and Sample 4 were obtained (step S36 ).

[0406] <Preparation of secondary battery> Sample 1, Sample 2, Sample 3 and Sample 4 are correct. Used as the electrode active material, CR2032 type (diameter 20 mm, height 3.2 mm) coin type A secondary battery was fabricated.

[0407] Sample 1, Sample 2, Sample 3 and Sample ple 4 was used as the positive electrode active material, and acetylene black (AB) and polypropylene (PP) were used. Polyvinylidene fluoride (PVDF) and positive electrode active material: AB:PVDF = 95:3:2 (weight ratio) The components were mixed in a ratio of 1 to 10, and a slurry was prepared. The slurry was then applied to a current collector to prepare a positive electrode.

[0408] The counter electrode was made of lithium metal.

[0409] The electrolyte contained 1 mol / L of lithium hexafluorophosphate (LiPF6). The electrolyte used was ethylene carbonate (EC) and diethyl carbonate (DEC). EC:DEC = 3:7 (volume ratio), vinylene carbonate (VC) was mixed at 2 wt%. The following was used.

[0410] The separator was made of polypropylene with a thickness of 25 μm.

[0411] The positive electrode can and the negative electrode can were made of stainless steel (SUS).

[0412] <Cycle characteristics> The secondary battery was charged at 25°C or 45°C using CCCV (0.5 C , 4.6V, final current 0.05C), discharge CC (0.5C, 2.5V) repeatedly charged and discharged. The results are shown in Figures 26A, 26B, 27A, and 27B. The horizontal axis of Figures 26A, 26B, 27A and 27B represents cycles, and the vertical axis represents discharge. Capacity.

[0413] 26A and 26B show the positive and negative polarities of Sample 1 and Sample 2, respectively. The graph shows the cycle characteristics of secondary batteries using the electrode active material. Sample 1 is shown by the solid line, and Sample The dotted lines indicate the cycle characteristics at 25°C. , and FIG. 26B shows the results of the cycle characteristics at 45°C.

[0414] 27A and 27B show the positive and negative polarities of Sample 3 and Sample 4, respectively. The graph shows the cycle characteristics of secondary batteries using the electrode active material. Sample 3 is shown by the solid line, and Sample The dotted lines indicate the cycle characteristics at 25°C. , and FIG. 27B shows the results of the cycle characteristics at 45°C.

[0415] When the amount of mixture 903 in the annealing was 2.4 g, fluorine was used as the aluminum source. Both aluminum chloride and aluminum hydroxide were used. The cycle characteristics were obtained.

[0416] On the other hand, when comparing the cycle characteristics when the amount of mixture 903 in the annealing is 30 g, When aluminum fluoride is used, the As mentioned above, the DSC results show that aluminum fluoride It has been suggested that this does not inhibit the eutectic reaction between aluminum fluoride and magnesium fluoride. When aluminum fluoride is used in manufacturing the positive electrode active material of one embodiment of the present invention, In the production of positive electrode active materials, the reaction can be favorably controlled and two-component catalysts with excellent properties can be obtained. The following battery was obtained. [Explanation of symbols]

[0417] SW1: Switch, SW2: Switch, SW3: Switch, 78i: Current, 91: Material, 92: Substance, 93: Substance, 94: Substance, 95: Metal oxide, 100: Positive electrode active material, 210 : Electrode laminate, 211a: Positive electrode, 211b: Negative electrode, 212a: Lead, 212b: Lead , 214: separator, 215a: joint, 215b: joint, 217: fixing member, 25 0: secondary battery, 251: exterior body, 261: bent portion, 262: seal portion, 263: seal 271: Ridge line; 272: Valley line; 273: Space; 300: Secondary battery; 301: Positive electrode can 302: negative electrode can, 303: gasket, 304: positive electrode, 305: positive electrode current collector, 306: Positive electrode active material layer, 307: negative electrode, 308: negative electrode current collector, 309: negative electrode active material layer, 310: Parameter, 400: eyeglass-type device, 400a: frame, 400b: display unit, 401: Headset type device, 401a: microphone part, 401b: flexible pipe, 401 c: earphone unit, 402: device, 402a: housing, 402b: secondary battery, 403: Device, 403a: housing, 403b: secondary battery, 405: wristwatch-type device, 405a : display unit, 405b: belt unit, 406: belt-type device, 406a: belt unit, 40 6b: wireless power receiving unit, 500: secondary battery, 501: positive electrode current collector, 502: positive electrode active Material layer, 503: Positive electrode, 504: Negative electrode current collector, 505: Negative electrode active material layer, 506: Negative electrode, 5 07: separator, 508: electrolyte, 509: exterior body, 510: positive electrode lead electrode, 511 : negative electrode lead electrode, 600: secondary battery, 601: positive electrode cap, 602: battery can, 603 : positive electrode terminal, 604: positive electrode, 605: separator, 606: negative electrode, 607: negative electrode terminal, 6 08: Insulating plate, 609: Insulating plate, 610: Gasket, 611: PTC element, 612: Safety All valve mechanisms, 613: conductive plate, 614: conductive plate, 615: module, 616: conductor, 61 7: Temperature control device, 900: Circuit board, 902: Mixture, 903: Mixture, 904: Mixture Object, 910: Label, 911: Terminal, 912: Circuit, 913: Secondary battery, 914: Antenna Na, 915: seal, 916: layer, 917: layer, 918: antenna, 920: display device, 921: sensor, 922: terminal, 930: housing, 930a: housing, 930b: housing, 93 1: negative electrode, 932: positive electrode, 933: separator, 950: wound body, 951: terminal, 952 : terminal, 980: secondary battery, 981: film, 982: film, 993: winding body, 9 94: negative electrode, 995: positive electrode, 996: separator, 997: lead electrode, 998: lead Electrode, 7100: Portable display device, 7101: Housing, 7102: Display unit, 7103: Operation button Tan, 7104: Secondary battery, 7200: Portable information terminal, 7201: Housing, 7202: Display Part, 7203: Band, 7204: Buckle, 7205: Operation button, 7206: Input / output Terminal, 7207: Icon, 7300: Display device, 7304: Display unit, 7400: Mobile phone Handset, 7401: Housing, 7402: Display, 7403: Operation buttons, 7404: External connection Port, 7405: Speaker, 7406: Microphone, 7407: Secondary battery, 7500: Electronic Cigarettes, 7501: Atomizers, 7502: Cartridges, 7504: Secondary batteries, 800 0: Display device, 8001: Housing, 8002: Display unit, 8003: Speaker unit, 8004: Secondary battery, 8021: charging device, 8022: cable, 8024: secondary battery, 8025: Secondary battery, 8100: lighting device, 8101: housing, 8102: light source, 8103: secondary battery ,8104: Ceiling, 8105: Side wall, 8106: Floor, 8107: Window, 8200: Indoor unit, 8201: Housing, 8202: Air outlet, 8203: Secondary battery, 8204: Outdoor unit, 8300 : Electric refrigerator-freezer, 8301: Housing, 8302: Refrigerator door, 8303: Freezer door, 8 304: Secondary battery, 8400: Automobile, 8401: Headlight, 8406: Electric motor -, 8500: Automobile, 8600: Scooter, 8601: Side mirror, 8602: Secondary Battery, 8603: Turn signal light, 8604: Under-seat storage, 9600: Tablet device, 9 625: Switch, 9626: Switch, 9627: Switch, 9628: Operation switch , 9629: fastener, 9630: housing, 9630a: housing, 9630b: housing, 9631 :Display part, 9631a:Display part, 9631b:Display part, 9633:Solar cell, 9634: Charge / discharge control circuit, 9635: Storage battery, 9636: DCDC converter, 9637: Converter Data, 9640: Moving parts< / dsc>

Claims

1. A secondary battery having a positive electrode, the positive electrode has a positive electrode active material, the positive electrode active material includes lithium cobalt oxide, an element X substituted at a lithium position of the lithium cobalt oxide, and a halogen; the element X is magnesium, calcium, zirconium, lanthanum or barium; When the depth of charge is 0.8 or more, the positive electrode has a positive electrode active material having a pseudospinel crystal structure, The pseudospinel crystal structure has a space group of R-3m, and the coordinates of cobalt in a unit cell are Co(0,0,0.5), and the coordinates of oxygen are O(0,0,x), with 0.20≦x≦0.

25.

2. A secondary battery having a positive electrode, the positive electrode has a positive electrode active material, the positive electrode active material includes lithium cobalt oxide, an element X substituted at a lithium position of the lithium cobalt oxide, and a halogen; the element X is magnesium, calcium, zirconium, lanthanum or barium; When the depth of charge is 0.8 or more, the positive electrode has a positive electrode active material having a pseudospinel crystal structure, The pseudospinel crystal structure has a first diffraction peak in the 2θ range of 19.10° to 19.50°, and a second diffraction peak in the 2θ range of 45.45° to 45.65°.

3. In claim 1 or claim 2, The number of atoms of the element X is 0.001 to 0.1 times the number of atoms of cobalt.

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