Secondary batteries

Abstract

To provide a positive electrode active material having a high capacity and excellent charge / discharge cycle characteristics, a positive electrode active material with good productivity, a positive electrode active material in which capacity reduction is suppressed, etc. Or to provide a high-capacity secondary battery, a secondary battery with excellent charge / discharge characteristics, a secondary battery with high safety or reliability, etc. [Solution] A positive electrode active material is obtained by a first heating step of heating a mixture of a first material, a second material, and a third material, and a second heating step of heating a mixture of the first material, a fourth material, and a fifth material, the total amount of which is 15 g or more, wherein the first material is a halide compound containing an alkali metal, the second material contains magnesium, the third material is a metal oxide containing metal A and cobalt, the fourth material contains nickel, and the fifth material contains aluminum, and each heating is performed in an atmosphere containing oxygen, and the temperature in the first heating step is 20°C or more lower than the temperature in the second heating step.

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 4).

[0007] 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]

[0008] [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]

[0009] [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, 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]

[0010] 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. Another object of the present invention is to provide a method for manufacturing a positive electrode active material. When used in lithium-ion secondary batteries, the decrease in capacity during charge / discharge cycles is suppressed. Another object of one embodiment of the present invention is to provide a positive electrode active material having a high capacity. Another object of the present invention is to provide a secondary battery having excellent charge-discharge characteristics. Another object of the present invention is to provide a secondary battery that can maintain a charged state at a high voltage for a long time. The objective of the present invention is to provide a positive electrode active material in which the elution of transition metals such as cobalt is suppressed even when the positive electrode is maintained. Another aspect of the present invention is to provide a secondary battery with high safety or reliability. This is one of the challenges.

[0011] 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

[0012] 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]

[0013] One aspect of the present invention is a first mixture in which a first material, a second material, and a third material are mixed. a first step of forming a mixture and a second step of heating the first mixture to form a second mixture. and preparing a third mixture in which the second mixture, the fourth material, and the fifth material are mixed. a third step of preparing a fourth mixture; and a fourth step of heating the third mixture to prepare a fourth mixture. and a first material is a halide compound having an alkali metal, and a second material is the first material has magnesium, and the third material is a metal oxide having an alkali metal and cobalt. the fourth material comprises nickel, the fifth material comprises aluminum, and the fourth In the fourth step, the third mixture is heated in a processing chamber of an annealing device. In step (b), the total amount of the third mixture heated in the treatment chamber is 15 g or more, and the second In a first step, the heating is performed in an atmosphere having oxygen, and in a second step, the heating The temperature range is 600°C to 950°C, and the time is 1 hour to 100 hours. In the fourth step, the heating is carried out in an atmosphere containing oxygen, The heating temperature is between 600°C and 950°C, and the heating time is between 1 hour and 100 hours. The heating temperature in the fourth step is set to be lower than the heating temperature in the second step. This is a method for producing a positive electrode active material at a temperature 20°C or more lower than that of the conventional method.

[0014] In the above structure, the alkali metal is lithium, and the first material is lithium fluoride. and the second material is preferably magnesium fluoride.

[0015] In the above configuration, the third material is nickel hydroxide, and the fourth material is aluminum hydroxide. Preferably, it is a minium.

[0016] Alternatively, one embodiment of the present invention is a method for manufacturing a semiconductor device, comprising: A first step of preparing a mixed first mixture, a second step of heating the first mixture, and and a second step of preparing a compound, the first material being a halogen compound having an alkali metal. the second material is a magnesium compound, and the third material is nickel, aluminum, the fourth material is at least one selected from the group consisting of aluminum, titanium, vanadium, and chromium; In the second step, heating is performed to form a metal oxide having an alkali metal and cobalt. The temperature range is 600°C to 950°C, and the time is 1 hour to 100 hours. The first material, the second material, and the third material are The materials were mixed, and differential scanning calorimetry showed a minimum value in the range of 620°C to 920°C. a first peak corresponding to the first peak being a negative peak; .

[0017] In the above structure, the alkali metal is lithium, and the first material is lithium fluoride. and the second material is preferably magnesium fluoride.

[0018] In the above-mentioned configuration, the third material contains nickel, and the first mixture contains the first material, A mixture of a second material, a third material, a fourth material, and a fifth material. , the fifth material preferably comprises aluminum.

[0019] In the above structure, the third material is preferably nickel hydroxide.

[0020] In the above-mentioned configuration, the half width of the first peak is preferably less than 100°C.

[0021] In the above configuration, the measurement temperature range of the differential scanning calorimetry is at least 200°C or higher. It is preferable to include a range of 850°C or less.

[0022] In the above-mentioned structure, the heating atmosphere in the second step preferably contains oxygen. I wish.

[0023] Alternatively, one embodiment of the present invention is a method for manufacturing a semiconductor device, comprising: A first step of preparing a mixed first mixture, a second step of heating the first mixture, and and a second step of preparing a compound, the first material being a halogen compound having a metal A. the second material comprises magnesium, and the third material comprises nickel, aluminum, the fourth material is one or more selected from metal A and titanium, vanadium, and chromium; and cobalt, where metal A is an alkali metal, and in the second step Heating is carried out at a temperature range of 600°C to 950°C for 1 hour to 100 hours. The first material, the second material and the third material are and a third material, and the mixture is heated at a temperature of 600°C to 950°C for 1 hour or more. When heated for 00 hours or less and analyzed by X-ray diffraction, 2θ is 39.5° or more and 41° or less. The first diffraction peak has a maximum at 2θ=19.0°±0.25°, 2 θ=31.3°±0.25°, 2θ=36.9°±0.15° and 2θ=59.4°± This is a method for producing a positive electrode active material in which the four peaks at 0.25° are not observed.

[0024] In the above configuration, the metal A is lithium, and the first material is lithium fluoride. Preferably, the second material is magnesium fluoride.

[0025] In the above-mentioned configuration, the third material contains nickel, and the first mixture contains the first material, A mixture of a second material, a third material, a fourth material, and a fifth material. , the fifth material preferably comprises aluminum.

[0026] In the above structure, the third material is preferably nickel hydroxide. [Effects of the Invention]

[0027] 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. 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]

[0028] [Figure 1] 1A, 1B, and 1C are diagrams illustrating a method for inspecting a substance. [Figure 2] 2A, 2B, and 2C 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] 5A, 5B, and 5C are diagrams illustrating a coin-type secondary battery. [Figure 6] 6A, 6B, 6C, and 6D are diagrams illustrating a cylindrical secondary battery. [Figure 7] 7A and 7B are diagrams illustrating an example of a secondary battery. [Figure 8] 8A, 8B, 8C, and 8D are diagrams illustrating examples of secondary batteries. [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] 11A, 11B, and 11C are diagrams illustrating a laminated secondary battery. [Figure 12] 12A and 12B are diagrams 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] 15A, 15B, and 15C are diagrams illustrating a method for producing a secondary battery. [Figure 16] 16A, 16B1, 16B2, 16C, and 16D are diagrams illustrating a bendable secondary battery. [Figure 17] 17A and 17B are diagrams illustrating a bendable secondary battery. [Figure 18] 18A, 18B, 18C, 18D, 18E, 18F, 18G, and 18H are diagrams illustrating an example of an electronic device. [Figure 19] 19A, 19B, and 19C are diagrams illustrating an example of an electronic device. [Figure 20] FIG. 20 is a diagram illustrating an example of an electronic device. [Figure 21]21A, 21B, and 21C are diagrams illustrating an example of a vehicle. [Figure 22] 22A, 22B, and 22C are diagrams illustrating an example of an electronic device. [Figure 23] 23A, 23B, and 23C are diagrams showing the results of evaluation using DSC. [Figure 24] 24A and 24B are diagrams showing the results of evaluation using DSC. [Figure 25] FIG. 25 shows the results of evaluation using DSC. [Figure 26] FIG. 26 is a diagram showing cycle characteristics of a secondary battery. [Figure 27] FIG. 27 is a diagram showing the results of XRD evaluation. [Figure 28] FIG. 28 is a diagram showing the results of XRD evaluation. [Figure 29] FIG. 29 is a diagram showing the results of XRD evaluation. [Figure 30] FIG. 30 is a diagram showing the results of XRD evaluation. [Figure 31] 31A and 31B are graphs showing cycle characteristics of the secondary battery at a charging voltage of 4.60V. [Figure 32] 32A and 32B are graphs showing cycle characteristics of the secondary battery at a charging voltage of 4.62V. [Figure 33] 33A and 33B are graphs showing cycle characteristics of the secondary battery at a charging voltage of 4.64V. [Figure 34] 34A and 34B are graphs showing cycle characteristics of the secondary battery at a charging voltage of 4.66V. [Figure 35] Fig. 35A is a graph showing the cycle characteristics of a secondary battery using Sample 6. Fig. 35B is a graph showing the initial charge-discharge curve and the 50th charge-discharge curve of a secondary battery using Sample 6 at 50°C and a charge voltage of 4.60V. [Figure 36]Fig. 36A is a graph showing the cycle characteristics of a secondary battery using Sample 7. Fig. 36B is a graph showing the initial charge-discharge curve and the 50th charge-discharge curve of a secondary battery using Sample 7 at 50°C and a charge voltage of 4.60V. [Figure 37] Fig. 37A is a graph showing the cycle characteristics of a secondary battery using Sample 8. Fig. 37B is a graph showing the initial charge-discharge curve and the 50th charge-discharge curve of a secondary battery using Sample 8 at 50°C and a charge voltage of 4.60V. [Figure 38] 38A to 38C are diagrams showing the continuous charging characteristics of the secondary battery at a voltage of 4.60V. [Figure 39] 39A to 39C are diagrams showing continuous charging characteristics of the secondary battery at a voltage of 4.62V. [Figure 40] 40A to 40C are diagrams showing continuous charging characteristics of the secondary battery at a voltage of 4.64V. [Figure 41] 41A to 41C are diagrams showing continuous charging characteristics of a secondary battery at a voltage of 4.66V. [Figure 42] FIG. 42 is a diagram illustrating the endurance time in the continuous charging test. [Figure 43] 43A and 43B are diagrams showing the results of XRD evaluation. [Figure 44] 44A and 44B are diagrams showing the results of XRD evaluation. DETAILED DESCRIPTION OF THE INVENTION

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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 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.

[0036] 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 can be made from simple pure lithium cobalt oxide or cobalt-rich It is known that layered rock salt type positive electrode active materials do not usually have this crystal structure.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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 negative electrode to the positive 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.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] Constant current charging refers to a method of charging at a constant charge rate. For example, when the charging reaches the upper limit voltage, the voltage is kept constant and charging is continued. Discharging refers to, for example, a method of discharging at a constant discharge rate.

[0048] (Embodiment 1) In this embodiment, a manufacturing method and the like of a positive electrode active material of one embodiment of the present invention will be described.

[0049] The positive electrode active material of one embodiment of the present invention is a compound of a halogen compound containing an alkali metal A and magnesium. A compound containing ammonium and a metal oxide containing an alkali metal and a transition metal are mixed. This can be achieved by annealing (which may also be expressed as heating, heat treatment, etc.). In the annealing process, in addition to the three materials, a compound containing a metal M is added. By adding a compound containing a metal M, the structural stability of the positive electrode active material is improved. As a result, the charging voltage of the secondary battery can be increased. - The density increases. Also, the life of the secondary battery is extended.

[0050] In the metal oxides having an alkali metal A and a transition metal, the transition metal is, for example, cobalt. Preferably, the alkali metal A is one or more of manganese, nickel, and iron. The transition metal contained in the metal oxide is an element different from the metal M described below. It is preferable that:

[0051] Metal oxides containing alkali metals and transition metals have, for example, a layered rock salt structure. Alternatively, for example, it has a spinel structure.

[0052] The metal M is, for example, nickel, aluminum, manganese, titanium, vanadium, iron and One or more selected from chromium, especially one or more of nickel and aluminum is preferred.

[0053] mixing a halogen compound containing an alkali metal A with a compound containing magnesium; It is suggested that heating causes a eutectic reaction or lowers the eutectic point. Or, a eutectic reaction occurs. Or, the eutectic point decreases. For example, the melting point of an alkali metal A and a transition metal B is lower than that of the melting point of the other. Magnesium can be added to the surface and interior of the metal oxide having the formula:

[0054] On the other hand, halogen compounds containing alkali metal A, compounds containing magnesium, and In addition to the three metal oxides containing alkali metals A and transition metals, By adding a compound containing an alkali metal A, a halogen compound containing magnesium is The eutectic reaction of the compound having the above structure may be inhibited due to the following reasons: The compound containing metal M is formed by the reaction of magnesium at a temperature lower than the temperature at which the eutectic reaction is suggested. and at least one of a compound containing sodium and a halogen compound containing an alkali metal A. Reactions include:

[0055] The likelihood of the eutectic reaction occurring also depends on the annealing atmosphere, pressure, and the processing conditions of the annealing apparatus. This may vary depending on the total amount of material being annealed relative to the internal volume of the chamber.

[0056] The compound containing the metal M is a mag- netic compound at a temperature lower than the temperature at which the eutectic reaction is suggested. The reaction amount with compounds containing nesium and halogen compounds containing alkali metal A is small. It is preferable that

[0057] In addition, when the compound containing the metal M is likely to inhibit the eutectic reaction, for example, an alkali metal Group A halide compounds, magnesium compounds, and alkali metal A and and a metal oxide having a transition metal, and then annealing the mixture. and annealing the mixture.

[0058] The halogen with alkali metal A at a temperature lower than the temperature at which the eutectic reaction is suggested The reaction of a compound containing magnesium with a compound containing metal M is as follows: It can be inspected by the following method.

[0059] In addition, the substances that form a eutectic reaction with halogen compounds containing alkali metal A are , magnesium-containing compounds have been described, but instead of magnesium-containing compounds, A compound containing element X can be used. Element X can be calcium, zirconium, or the like. Elements such as copper, lanthanum, and barium can be used as the element X. Elements such as lithium, sodium, and zinc can be used. In addition to the element X, magnesium may be contained. The above may be used in combination.

[0060] <dsc> Figure 1A shows the reaction between substance 91 and substance 92 as measured by DSC (Differential Scanning Calorimetry). An example of testing using classical scanning calorimetry is shown below. Here, substance 91 is a halide compound with alkali metal A, and substance 92 is an element X. It is a compound having the formula:

[0061] In step S01, a substance 91 and a substance 92 are prepared.

[0062] Next, in step S02, the substance 91 and the substance 92 are mixed to obtain a mixture 81. .

[0063] Next, in step S03, an inspection is performed. Here, DSC is performed as the inspection. In step C, the measurement temperature is scanned and the change in the amount of heat is observed. This change in the amount of heat is, for example, due to melting. It is produced by endothermic reactions such as crystallization and exothermic reactions such as crystallization.

[0064] For materials 91 and 92, a change in heat quantity was observed at temperature T(1), suggesting an endothermic reaction. It is preferable that

[0065] Figure 1B shows an example of examining the reactions of substances 91, 92, and 93 using DSC. Here, the substance 93 is a compound having a metal M(1). The metal M(1) is The description of the metal M can be referred to.

[0066] The mixture 81 of materials 91, 92, and 93 is examined using DSC. The reaction at temperature T(1) observed in the test at A is Tests can be carried out to see how much inhibition there is.

[0067] More specifically, for example, in the test shown in FIG. 1A, DSC is performed, and an endothermic reaction occurs at temperature T(1). A peak indicating this is observed at peak intensity I(1). Here, the temperature T(1) is preferably is 620°C or higher and 920°C or lower, more preferably 700°C or higher and 850°C or lower, and even more preferably The temperature is generally between 700°C and 770°C.

[0068] In the test shown in FIG. 1B, a DSC is performed to obtain a temperature-heat flow curve, preferably [Temperature T(1) - 50℃] or more [Temperature T(1) + 50℃] or less, more preferably [Temperature T(1 ) -30℃] or more [temperature T(1) + 30℃] or less, 0.3 times the peak intensity I(1) If a peak indicating an endothermic reaction is observed at an intensity above this level, the inhibition of the eutectic reaction is significant. In this case, the half-width of the observed peak must not exceed 100°C. Preferably, the temperature is 50°C or lower, more preferably 30°C or lower.

[0069] Here, the peak intensity I(1) is the ratio of the weight of the mixture to the weight of the substances 91 and 92. It is preferable to perform calculation by normalizing the sum ratio.

[0070] Here, the scanning rate of the DSC is, for example, 20°C / min, preferably, for example, 2°C / min. n. or more and 30°C / min. or less is preferable.

[0071] In addition, the differential waveform of the DSC was obtained as the peak intensity, and the temperature-heat flow curve before differentiation was The heights of the maximum and minimum points observed in the differential waveform around the temperature at which the peak was observed The difference between the maximum point observed in the differential waveform and the peak position observed may be used as the peak intensity. The absolute value of the difference between the peak position of the temperature-heat flow curve and the half-width of the peak of the temperature-heat flow curve is It is preferable that the value is smaller than 0.5. The minimum point observed in the differential waveform is the peak position observed. The absolute value of the difference between the position and the peak position of the temperature-heat flow curve is also the half value of the peak of the temperature-heat flow curve. Preferably it is less than 0.5 times the width.

[0072] Figure 1C shows the reactions of substances 91, 92, 93, and 94, as determined by DSC. Here, the substance 94 is a compound containing a metal M(2). ) can refer to the description of metal M. Also, metal M(2) can be used as metal M(1). It is preferred that the metal contained in the SiO 2 layer is different from that of the SiO 2 layer.

[0073] The mixture 81 of substances 91, 92, 93 and 94 was examined using DSC. The reaction at temperature T(1) observed in the test in FIG. 1A is The degree to which the reaction is inhibited by adding the substance 94 can be examined. ) is inhibited, substitute substance 93 in Figure 1B. The substance 93 and the substance 94 are then inspected. ) contributes significantly to the inhibition of the reaction.

[0074] In step S01 of FIGS. 1A, 1B, and 1C, a metal oxide 95 is added and inspected. The metal oxide 95 may be a metal oxide having an alkali metal A and a transition metal A. It is an oxide.

[0075] When metal oxide 95 is added and DSC is performed, a peak is observed compared to when it is not added. The temperature T(1) may be about 100° C. higher, for example.

[0076] As the alkali metal A, for example, lithium, sodium, potassium, etc. may be used. It is preferable to use lithium as the metal oxide containing an alkali metal and a transition metal. For example, a metal oxide having a layered rock salt structure may be used. A metal oxide having a structure represented by the group R-3m may be used.

[0077] Metal oxides containing alkali metals and transition metals include lithium cobalt oxide, manganese oxide, and manganese oxide. Lithium nickel oxide, lithium nickel oxide, cobalt with some of the cobalt replaced by manganese lithium cobalt oxide, lithium cobalt oxide in which some of the cobalt is replaced by nickel, or nickel Lithium manganese cobalt oxide can be used.

[0078] When the metal oxide containing an alkali metal A and a transition metal A contains nickel, for example, The ratio of nickel atoms (Ni) to the sum of cobalt and nickel atoms (Co+Ni) is The ratio Ni / (Co+Ni) is preferably less than 0.1 and is 0.075 or less. If the charged state at a high voltage is maintained for a long time, the transition metals from the positive electrode active material are converted into the positive electrode active material. However, if the nickel content is in the above range, the metal may dissolve in the electrolyte, causing the crystal structure to collapse. By doing so, it may be possible to suppress the elution of the transition metal from the positive electrode active material 100.

[0079] Examples of halogen compounds containing an alkali metal A include lithium fluoride and sodium fluoride. Examples include ammonium, potassium fluoride, lithium chloride, sodium chloride, calcium chloride, etc. In particular, lithium fluoride is preferable because it melts easily in the annealing step described below.

[0080] As the compound having the element X, a compound having magnesium can be used. Examples of magnesium-containing compounds include magnesium fluoride, magnesium oxide, and magnesium hydroxide. Examples of magnesium oxide include magnesium chloride, magnesium carbonate, and magnesium chloride.

[0081] In the preparation of the positive electrode active material according to one embodiment of the present invention, a halogen compound having an alkali metal A is Lithium fluoride was used as the substance, and magnesium fluoride was used as the compound containing magnesium. It is preferable to use lithium fluoride. By mixing lithium fluoride, the melting point of magnesium fluoride is lower than that of magnesium fluoride. This eutectic phenomenon can be utilized to produce the positive electrode active material.

[0082] As the compound having the metal M, for example, a hydroxide or oxide of the metal can be used. When one of the metals in metal M is nickel, for example, nickel hydroxide, nickel oxide, When one of the metals in the metal M is aluminum, for example, , aluminum hydroxide, aluminum oxide, etc. can be used. When one of the groups is manganese, for example, manganese hydroxide, manganese oxide, etc. can be used. can.

[0083] Alternatively, a metal alkoxide may be used as the compound containing the metal M. For example, Titanium isopropoxide, titanium tetramethoxy, etc. can be used.

[0084] The positive electrode active material of one embodiment of the present invention is the above-described positive electrode active material having an alkali metal A and a transition metal. It is preferable that the positive electrode active material of one embodiment of the present invention contains particles. For example, the particles may be composed of a metal having an alkali metal A and a transition metal B, as described above. It is preferable that the material contains an oxide.

[0085] The positive electrode active material according to one embodiment of the present invention preferably contains magnesium and a metal M. The positive electrode active material particles according to one embodiment of the present invention may further include the above-described alkali metal A In the case where the metal oxide containing a transition metal is included, the metal oxide is more Specifically, for example, a small amount of magnesium and metal M is present on the surface of the particle and in its vicinity. At least one of them.

[0086] <xrd> XRD may be performed as shown in FIG. 1B or FIG. 1C. , element X contained in substance 92 and metal elements contained in substance 93 and / or substance 94 If the presence of a compound containing one or more of and is suggested, a eutectic reaction of substance 91 and substance 92 is In the test, the temperature is first set at 600℃ or higher and 950℃ or lower. The sample was heated within the temperature range of 1 hour to 100 hours, and then XRD evaluation was performed. cormorant.

[0087] When the metal oxide containing an alkali metal A and a transition metal has a rock salt layer structure, for example, For example, when a peak due to the spinel structure is observed in XRD, the eutectic reaction is evident. More specifically, when aluminum is used as the metal M, In XRD, 2θ = 19.0° ± 0.25°, 2θ = 31.3° ± 0.25°, 2 Four peaks at θ=36.9°±0.15° and 2θ=59.4°±0.25° If at least one of these is observed, it is determined that the eutectic reaction is significantly inhibited. It is suggested that the peaks are due to MgAl2O4. It is preferable that the peak intensity is not high or is sufficiently low. The strongest peak is observed in the 2θ range of 15° to 90°. Compared with the intensity of the observed peaks, it is suggested that they are due to MgAl2O4, 2θ = 19.0°±0.25°, 2θ=31.3°±0.25°, 2θ=36.9°±0.15 All four peaks at 2θ=59.4°±0.25° and 2θ=59.4°±0.25° were 0.02 times or more intense. It is not desirable to be observed.

[0088] Here, the substance 91, the substance 92, and at least one of the substances 93 and 94 are mixed. After heating, XRD analysis was performed and no peaks were observed indicating that the eutectic reaction was significantly inhibited. Even if the measurement is performed, at least one of the substances 91, 92, 93, and 94 When metal oxide 95 is mixed in addition to the above and heated, The peak intensity due to the eutectic reaction is high, and the peak intensity is considered to be a significant inhibition of the eutectic reaction. In some cases, the peak may not be observed.

[0089] <Production method> 2A, 2B, and 2C show the substances 91, 92, 93, and 94 mentioned in FIG. 94 and a metal oxide 95. show.

[0090] For the sake of simplicity, some steps are omitted in the manufacturing flow shown in this specification. This may occur.

[0091] The flow shown in FIG. 2A is a flow chart of the process in which the substances 91, 92, and 93 are prepared in step S11. 93, a material 94 and a metal oxide 95 are mixed, and annealed in step S34. In step S36, the positive electrode active material 100 is obtained.

[0092] In the inspection of FIG. 1B or FIG. 1C, at least one of the substance 93 and the substance 94 is a substance If it is determined that the reaction suggesting the eutectic of 91 and substance 92 is significantly inhibited, It is preferable to obtain the positive electrode active material 100 using the flow shown in the following. If the total amount of acetone is large, the flow shown in Figure 2B can be used for more uniform processing. This may be preferable in some cases. Specifically, for example, the material is in the form of powder, and If the total amount of powder is 15 g or more, the flow shown in Figure 2B can be used. If the total amount is, for example, 15 g or more, the surface of the powder will be in the annealing atmosphere in one annealing. In such cases, the eutectic reaction is more inhibited. By using the flow shown in Figure 2B, the eutectic reaction can be more reliably generated. Alternatively, the annealing atmosphere, pressure, and annealing equipment may be adjusted. The total amount of material to be annealed relative to the volume of the processing chamber of the device may be adjusted. If the total amount is less than 15g, for example, the surface of the powder is easily exposed to the annealing atmosphere. This may prevent the eutectic reaction from being inhibited. If the volume of the heating furnace is, for example, 10 L or more, 20 L or more, or 30 L or more, Above.

[0093] The flow shown in FIG. 2B is for treating the materials 93 and 94 after annealing in step S34. In step S11, the material 91, the material 92, and the gold are prepared. The metal oxide 95 is mixed and annealed in step S34. The substance 93 and the substance 94 are added to the obtained mixture and mixed, and in step S55, an aniline is added. Then, in step S36, the positive electrode active material 100 is obtained.

[0094] By using the flow shown in FIG. 2B, the substance 91 and the substance 92 are The inhibition of the eutectic reaction of the substance 92 is suppressed.

[0095] In addition, it was determined that substance 94 significantly inhibits the reaction that suggests the eutectic formation of substances 91 and 92. If it is determined that the substance 93 does not significantly inhibit the activity, for example, the flow chart shown in FIG. 2C is used. - can also be used.

[0096] The flow shown in FIG. 2C is a flow chart of the process in which the substances 91, 92, and 93 are prepared in step S11. The metal oxide 95 is mixed with the silicon dioxide 93 and annealed in step S34. The substance 94 is added to the mixture obtained in step S34 and mixed, and annealed in step S55. Then, in step S36, the positive electrode active material 100 is obtained.

[0097] <Production method 2> An example of the manufacturing method shown in FIG. 2B is shown in FIG. 3. In the manufacturing method shown in FIG. Metal oxides containing metal A and transition metals, including alkali metals and cobalt An example of using a metal oxide is shown below. Also, as a compound having element X, magnesium An example in which a compound having the formula:

[0098] <Step S11> As shown in step S11 of Fig. 3, first, materials for the mixture 902 are prepared. Lithium fluoride (LiF) was prepared as a halogen compound containing an alkali metal (A), and magnesium Magnesium fluoride MgF2 is prepared as a compound containing lithium. LiF and magnesium fluoride MgF2 are in a molar ratio of LiF:MgF2=65:35. ) the effect of lowering the melting point of the mixture is greatest (Non-Patent Document 4). If the amount of lithium fluoride is too high, there is a concern that the lithium content will be too excessive and the cycle characteristics will deteriorate. Therefore, the molar ratio of lithium fluoride LiF to magnesium fluoride MgF2 is Li It is preferable that F: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=0.33 In this specification, "nearby" means more than 0.9 times the value. The value shall be less than 1.1 times.

[0099] 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 step S11 of 3, acetone is used.

[0100] <Step S12> Next, in step S12, the materials of the mixture 902 are mixed and crushed. The process can be carried out by either a dry method or a wet method, but the wet method is preferred because it allows for finer pulverization. For mixing, a ball mill, a bead mill, etc. can be used. When using zirconia balls as media, it is preferable to use zirconia balls as media. It is preferable to carry out the blending and grinding steps sufficiently to pulverize the mixture 902 into fine powder.

[0101] <Steps S13 and S14> In step S13, the mixed and crushed materials are collected, and in step S14, Thus, mixture 902 is obtained.

[0102] The mixture 902 preferably has a D50 of, for example, 600 nm or more and 20 μm or less. It is more preferable that the particle size is 1 μm or more and 10 μm or less. 2, when mixed with a composite oxide containing lithium, a transition metal, and oxygen in a later process, In addition, it is easy to uniformly attach the mixture 902 to the surface of the composite oxide particles. If the mixture 902 is uniformly attached to the surface of the composite oxide particles, the mixture 902 will leak onto the surface layer of the composite oxide particles after heating. This is preferable because it is easy to distribute halogen and magnesium in the surface layer. If there is a region that does not contain magnesium, the pseudospinel crystal described below will form in the charged state. It may be difficult to achieve the structure.

[0103] <Step S25> Next, in step S25, a metal oxide containing alkali metal A and cobalt is The metal oxide 95 is prepared by mixing a material having an alkali metal A with a surface thereof. It can be obtained by firing a mixture of materials having the same structure. Metal oxides may also be used.

[0104] <Step S31> Next, in step S31, the mixture 902 and the metal oxide 95 are mixed. The number of cobalt atoms in oxide 95, TM, and the number of magnesium atoms in mixture 902, Mg The ratio with Mix1 is TM:MgMix1 = 1:y (0.005≦y≦0.05). It is preferable that TM:MgMix1=1:y (0.007≦y≦0.04). A ratio of TM:MgMix1 of about 1:0.02 is more preferable, and a ratio of TM:MgMix1 of about 1:0.02 is even more preferable.

[0105] The mixing in step S31 is carried out in a manner similar to that in step S12 in order not to destroy the particles of the metal oxide 95. It is preferable to set the conditions milder than those of the mixing in step S12. It is preferable to use conditions with a low number of revolutions or a short time. These are mild conditions. For mixing, a ball mill, bead mill, etc. can be used. When using a ball mill, for example, zirconia balls are used as the media. It is preferable.

[0106] <Steps S32 and S33> Next, in step S32, the mixed materials are collected, and in step S33, Mixture 903 is obtained.

[0107] <Step S34> Next, in step S34, the mixture 903 is annealed.

[0108] The annealing is preferably carried out at a suitable temperature and time. It varies depending on the size and composition of the metal oxide 95 particles. , a lower temperature or shorter time may be more preferable than a larger temperature.

[0109] For example, if the average particle diameter (D50) of the particles in step S25 is about 12 μm, annealing The temperature is preferably, for example, 600° C. or higher and 950° C. or lower. The annealing time is, for example, 3 hours or longer. It is preferable that the heating time is 10 hours or more, more preferable that the heating time is 60 hours or more.

[0110] On the other hand, when the average particle diameter (D50) of the particles in step S25 is about 5 μm, the annealing temperature The annealing temperature is preferably, for example, 600° C. or higher and 950° C. or lower. The annealing time is, for example, 1 hour or higher and 10 Preferably, it is less than 1 hour, and more preferably about 2 hours.

[0111] The temperature drop time after annealing is preferably, for example, 10 hours or more and 50 hours or less.

[0112] When the mixture 903 is annealed, the material with a low melting point (e.g., fluorine) in the mixture 902 is first annealed. It is thought that the lithium oxide (lithium chloride, melting point 848°C) melts and is distributed on the surface of the metal oxide particles. The presence of this molten material then causes a drop in the melting point of other materials, It is assumed that it will melt. For example, magnesium fluoride (melting point 1263℃) will melt and become a metal. It is thought to be distributed in the surface layer of the oxide 95 particles.

[0113] The elements contained in the mixture 902 distributed in the surface layer are dissolved in the particles of the metal oxide 95. It is thought that this is the case.

[0114] The diffusion of the elements contained in the mixture 902 occurs more in the surface layer than in the interior of the particles of the metal oxide 95. 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 ruthenium is high, the change in the crystal structure can be more effectively suppressed.

[0115] <Steps S35 and S36> Next, in step S35, the annealed material is collected, and in step S36, This gives a mixture 904.

[0116] <Step S41> Next, in step S41, a source of metal M is prepared. When metal M is aluminum, For example, the number of cobalt atoms in lithium cobalt oxide is 1, and the number of aluminum atoms in the metal source is 1. The molar concentration of nickel should be between 0.001 and 0.02 times. In this case, for example, the number of cobalt atoms in the lithium cobalt oxide is 1, and the number of cobalt atoms in the metal source is 1. The molar concentration of nickel in the solution should be between 0.001 and 0.02 times. In the case of nium and nickel, for example, the number of cobalt atoms in lithium cobalt oxide is is set to 1, and the molar concentration of aluminum in the metal source is 0.001 times or more and 0.02 times or less, At the same time, it is preferable that the molar concentration of nickel contained in the metal source is 0.001 times or more and 0.02 times or less. stomach.

[0117] In the subsequent step S42, when wet mixing is performed, the solvent is dissolved in the step S41. The medium is also prepared.

[0118] In step S41 of FIG. 3, for example, nickel hydroxide is used as the metal source and ammonia is used as the solvent. An example using seton is shown below.

[0119] <Step S42> Next, in step S42, the metal source and the solvent are mixed and pulverized. For the crushing, the conditions in step S12 etc. can be referred to.

[0120] <Step S43> Next, in step S43, the metal M source pulverized in step S42 is recovered.

[0121] <Step S44> Next, in step S44, a metal different from the metal contained in the metal M source prepared in step S41 is added. In the subsequent step S45, the metal M source is wet mixed. In this case, a solvent is also prepared in step S44. Then, aluminum hydroxide is prepared as a metal source, and acetone is prepared as a solvent.

[0122] <Step S45> Next, in step S45, the metal source and the solvent are mixed and pulverized. For the crushing, the conditions in step S12 etc. can be referred to.

[0123] <Step S46> Next, in step S46, the metal M source pulverized in step S45 is recovered.

[0124] <Step S53> Next, in step S53, the mixture 904, the metal M source recovered in step S43, and and the metal M source recovered in step S46 are mixed.

[0125] <Steps S54 and S55> Next, in step S54, the mixture is collected, and in step S55, the mixture 905 get.

[0126] <Step S56> Next, in step S56, the mixture 905 is annealed. The retention time within the temperature range is preferably 1 hour or more and 50 hours or less, and more preferably 2 hours or more. If the firing time is too short, the metal M formed on the surface layer will be The crystallinity of the compound may be low, or the diffusion of the metal M may be insufficient. However, if the baking time is too long, the metal M may expand. If the diffusion proceeds too much, the concentration in the surface layer and near the grain boundaries may become low. Decreases.

[0127] The specified temperature is preferably 500°C or higher and 1200°C or lower, and more preferably 700°C or higher and 920°C or lower. It is more preferable that the temperature is 800°C or higher and 900°C or lower, and it is even more preferable that the temperature is 800°C or higher and 900°C or lower. The crystallinity of the compound containing the metal M formed in the layer portion may be low. Diffusion may be insufficient, or organic matter may remain on the surface.

[0128] It is also preferable that the firing is carried out in an atmosphere containing oxygen. When the oxygen partial pressure is low, the firing temperature If the temperature is not lowered, there is a risk of cobalt being reduced.

[0129] In this embodiment, the specified temperature is set to 850° C. and is maintained for 2 hours. °C / h, and the oxygen flow rate is 10 L / min.

[0130] Regarding cooling after firing, it is preferable to take a long cooling time, as this makes it easier to stabilize the crystal structure. For example, it is preferable that the time required for the temperature to drop from the specified temperature to room temperature is 10 hours or more and 50 hours or less. Here, the baking temperature in step S56 is set to be lower than the baking temperature in step S34. For example, the baking temperature in step S56 is preferably lower than that in step S34. 20℃ or more lower, 30℃ or more lower, or 45℃ or more lower than the baking temperature in It is preferable that

[0131] <Steps S57 and S58> Next, in step S57, the cooled particles are collected. In the above process, positive electrode active material 100 is obtained in step S58.

[0132] <Production Method 3> Next, an example of the manufacturing method shown in FIG. 2C is shown in FIG. 4. In the manufacturing method shown in FIG. As metal oxides with alkali metals A and transition metals, alkali metals and cobalt In addition, as a compound containing element X, a compound containing magnesium is used. An example of using a compound containing sodium will be shown below.

[0133] <Step S11> Step S11 shown in FIG. 4 is a step of reacting a halogen compound containing an alkali metal A, magnesium This differs from FIG. 3 in that a gold electrode M(1) source is prepared in addition to the compound having M(1) and the solvent.

[0134] <Steps S12 to S14> Next, through steps S12, S13 and S14, an alkali metal A A mixture of a halide compound containing Mg(1), a compound containing Mg(1), and a gold electrode M(1) source A mixture 906 is obtained. The conditions of steps S12 to S14 are shown in FIG. You can refer to the description.

[0135] After step S14, the mixture 906 may be inspected.

[0136] <Step S25> Next, in step S25, a metal oxide containing alkali metal A and cobalt is The metal oxide 95 is prepared by mixing a material having an alkali metal A with a surface thereof. It can be obtained by firing a mixture of materials having the same structure. Metal oxides may also be used.

[0137] <Steps S31 to S33> Next, through steps S31, S32 and S33, a mixture 906 and A mixture 907, which is a mixture of metal oxides 95, is obtained. Steps S31 to S33 For the conditions, etc., please refer to the description in Figure 3.

[0138] After step S33, the mixture 907 may be inspected.

[0139] <Step S34> Next, in step S34, the mixture 907 is annealed. For details, please refer to the description of Figure 3.

[0140] <Step S35> Next, in step S35, the annealed powder is collected and mixed in step S36. Obtain compound 908.

[0141] <Step S47> Next, in step S47, a metal M(2) source and a solvent are prepared. The sol-gel method was applied to the metal M(2) source, aluminum isopropoxide, and the An example using isopropanol as the solvent is shown below.

[0142] <Step S53> Next, in step S53, aluminum isopropoxide is dissolved in isopropanol. The metal alkoxide 908 is dissolved and mixed further. The required amount of silane varies. If the particle size (D50) is about 20 μm, the metal oxide 95 The concentration of aluminum in aluminum isopropoxide is calculated by taking the number of cobalt atoms as 1. It is preferable to add the mixture 908 so that the amount of the soluble solids is 0.001 times or more and 0.02 times or less. It is preferable to stir the mixture in an atmosphere containing water vapor. The stirring time is determined based on the hydrolysis and reaction of the water and metal alkoxide in the atmosphere. The time may be long enough to cause the polycondensation reaction, for example, 4 hours, 25°C, and 90% humidity. This can be done under RH (Relative Humidity) conditions. In addition, in an atmosphere where humidity and temperature are not controlled, such as in a draft chamber Stirring may be carried out under an air atmosphere. In such a case, the stirring time may be longer. For example, it is preferable to leave the mixture at room temperature for 12 hours or more.

[0143] By reacting atmospheric moisture with metal alkoxide, the The sol-gel reaction can proceed slowly. Also, the reaction between metal alkoxide and water at room temperature can be This allows for a gentler reaction than, for example, heating at a temperature above the boiling point of the alcohol solvent. By proceeding with the sol-gel reaction slowly, A coating layer of uniform thickness and high quality can be formed.

[0144] <Steps S54 and S55> Next, in step S54, the precipitate is collected from the mixture, and in step S55, the precipitate is collected from the mixture. Compound 909 is obtained. The recovery method can be filtration, centrifugation, evaporation to dryness, etc. The precipitate can be washed with the same alcohol as the solvent used to dissolve the metal alkoxide. The collected residue is then dried to obtain a mixture 909. The drying process may be carried out at 80°C, for example. The mixture can be dried in a vacuum or by ventilation for 1 hour or more and 4 hours or less.

[0145] <Step S56> Next, in step S56, the mixture 909 is baked. The baking time is set within a specified temperature range. The retention time within the range of 1 hour to 50 hours is preferable, and the retention time within the range of 2 hours to 20 hours is preferable. If the baking time is too short, the compound containing the metal M(2) formed in the surface layer will The crystallinity of the material may be low, or the diffusion of metal M(2) may be insufficient. Or organic matter may remain on the surface. However, if the baking time is too long, the metal M( 2) The diffusion of the element 2 may proceed too far, resulting in a low concentration in the surface layer and near the grain boundaries. Productivity decreases.

[0146] The specified temperature is preferably 500°C or higher and 1200°C or lower, and more preferably 700°C or higher and 920°C or lower. It is more preferable that the temperature is 800°C or higher and 900°C or lower, and it is even more preferable that the temperature is 800°C or higher and 900°C or lower. The crystallinity of the compound containing the metal M(2) formed in the layer may be low. The diffusion of genus M(2) may be insufficient, or organic matter may remain on the surface. do.

[0147] It is also preferable that the firing is carried out in an atmosphere containing oxygen. When the oxygen partial pressure is low, the firing temperature If the temperature is not lowered, there is a risk that Co will be reduced.

[0148] In this embodiment, the specified temperature is set to 850° C. and is maintained for 2 hours. °C / h, and the oxygen flow rate is 10 L / min.

[0149] Regarding cooling after firing, it is preferable to take a long cooling time, as this makes it easier to stabilize the crystal structure. For example, it is preferable that the time required for the temperature to drop from the specified temperature to room temperature is 10 hours or more and 50 hours or less. Here, the baking temperature in step S56 is set to be lower than the baking temperature in step S34. Preferably, it is low.

[0150] <Steps S57 and S58> Next, in step S57, the cooled particles are collected. In the above process, positive electrode active material 100 is obtained in step S58.

[0151] 2 to 4, the metal M, the material 93, the material 94, and the material containing nickel or aluminum are used. However, one embodiment of the present invention is not limited to this. As described at the beginning of the embodiment, the positive electrode active material of one embodiment of the present invention contains an alkali metal A. Halide compounds containing magnesium, compounds containing alkali metals and transition metals and annealing (which may be expressed as heating, heat treatment, etc.) It is not necessary to have the metal M. When the metal M is not present, In some cases, a single annealing process is most preferable. This can improve productivity compared to multiple times.

[0152] This embodiment mode can be implemented in appropriate combination with other embodiment modes.

[0153] (Embodiment 2) In this embodiment, a positive electrode active material of one embodiment of the present invention will be described.

[0154] <Cathode active material> By using the positive electrode active material of one embodiment of the present invention, the capacity of a secondary battery can be increased and the charge / discharge This suppresses the decrease in discharge capacity due to charging and discharging cycles.

[0155] [Positive electrode active material structure] 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.

[0156] 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.

[0157] 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. .

[0158] 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.

[0159] 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.

[0160] 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.

[0161] 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.

[0162] 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.

[0163] 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.

[0164] 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.

[0165] 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.

[0166] 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 4.62 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.

[0167] 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.

[0168] 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.

[0169] 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.

[0170] 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.

[0171] 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.

[0172] 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.

[0173] 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 about 0.02. The concentration of element X shown in the figure is determined by elemental analysis of the entire particle of the positive electrode active material using, for example, ICP-MS. It may be a value obtained by the calculation, or it may be a value based on the composition of raw materials in the process of producing the positive electrode active material. Good too.

[0174] 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.

[0175] This embodiment mode can be implemented in appropriate combination with other embodiment modes.

[0176] (Embodiment 3) 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.

[0177] [Positive electrode] The positive electrode has a positive electrode active material layer and a positive electrode current collector.

[0178] <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.

[0179] 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.

[0180] 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. Bottom is more preferable.

[0181] 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.

[0182] 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.

[0183] A graphene compound may also be used as the conductive additive.

[0184] 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).

[0185] 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.

[0186] 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.

[0187] 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.

[0188] 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.

[0189] 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.

[0190] 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.

[0191] 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.

[0192] 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.

[0193] 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

[0194] 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.

[0195] The binder may be used in combination with two or more of the above.

[0196] 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.

[0197] 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.

[0198] 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.

[0199] 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

[0200] <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 the material does not dissolve at the potential of the positive electrode. Aluminum alloys with added elements such as candium and molybdenum that improve heat resistance 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, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungste The current collectors are available in foil, plate (sheet), mesh, punched, etc. The current collector may be in the form of a metal, an expanded metal, or the like. It is preferable to use one with a thickness of 5 μm or more and 30 μm or less.

[0201] [Negative electrode] The negative electrode has a negative electrode active material layer and a negative electrode current collector. and a binder.

[0202] <Negative electrode active material> As the negative electrode active material, for example, an alloy-based material or a carbon-based material can be used.

[0203] 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.

[0204] In this specification, SiO refers to, for example, silicon monoxide. Alternatively, SiO refers to Si O x Here, it is preferable that x has a value close to 1. For example, x can be expressed as The ratio is preferably 0.2 or more and 1.5 or less, and more preferably 0.3 or more and 1.2 or less.

[0205] Carbon materials include graphite, easily graphitizable carbon (soft carbon), and non-graphitizable carbon (hard carbon). carbon nanotubes, graphene, carbon black, etc. stomach.

[0206] 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.

[0207] 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.

[0208] 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.

[0209] 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.

[0210] 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.

[0211] 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.

[0212] 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.

[0213] <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.

[0214] [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:

[0215] 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.

[0216] 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.

[0217] 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.

[0218] 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%.

[0219] Alternatively, a polymer gel electrolyte may be used in which a polymer is swollen with an electrolytic solution.

[0220] The use of polymer gel electrolyte increases safety against leakage etc. The pond can be made thinner and lighter.

[0221] 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.

[0222] 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.

[0223] 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.

[0224] 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.

[0225] 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 glass (Li3PO4-Li4SiO4, 50 Li4SiO4·50Li3BO3, etc.), oxide crystallized glass (Li 1.07 Al 0.6 9Ti 1.46 (PO4)3, Li 1.5 Al 0.5 Ge 1.5 (PO4)3, etc.) It can be obtained. Oxide-based solid electrolytes have advantages such as being stable in the atmosphere.

[0226] Halide-based solid electrolytes include LiAlCl4, Li3InBr6, LiF, LiC l, LiBr, LiI, etc. Also, composite materials obtained by filling these halide-based solid electrolytes into the pores of porous alumina or porous silica can also be used as solid electrolytes.

[0227] Also, different solid electrolytes may be mixed and used.

[0228] Among them, Li 1+x Al x Ti 2-x (PO4)3 (0 < x < 1) (hereinafter referred to as LATP) contains elements that the cathode active material used in the secondary battery of one aspect of the present invention may have, such as aluminum and titanium. Therefore, a synergistic effect can be expected for improving the cycle characteristics, which is preferable. Also, an improvement in productivity due to reduction of processes can be expected. In this specification and the like, the NASICON-type crystal structure refers to a compound represented by M2(XO4)3 (M: transition metal, X: S, P, As, Mo, W, etc.), and has a structure in which MO6 octahedrons and XO4 tetrahedrons share vertices and are three-dimensionally arranged. <{ addition, in this specification and the like, 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 octahedrons and XO4 tetrahedrons share vertices and are three-dimensionally arranged.

[0229] [Separator] Also, the secondary battery preferably has a separator. As the separator, for example, paper, non-woven fabric, glass fiber, ceramics, or synthetic fibers made of nylon (polyamide), vinylon (polyvinyl alcohol-based fiber), polyester, acrylic, polyolefin, polyurethane can be used. The separator is an envelope 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.

[0230] 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.

[0231] 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.

[0232] 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. .

[0233] 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,

[0234] [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.

[0235] (Fourth embodiment) 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.

[0236] [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.

[0237] 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.

[0238] 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.

[0239] 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.

[0240] 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.

[0241] 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.

[0242] 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.

[0243] 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.

[0244] [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.

[0245] 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.

[0246] 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 Coefficient) element. The positive electrode cap 601 is electrically connected to the positive electrode cap 601 via a positive electrode coefficient 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.

[0247] 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.

[0248] 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.

[0249] 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.

[0250] [Example of secondary battery structure] Another structural example of the secondary battery will be described with reference to FIGS.

[0251] 7A and 7B are diagrams showing the external appearance of a secondary battery. 900, the antenna 914 and the antenna 915 are connected. A label 910 is attached to the secondary battery 913. Furthermore, as shown in FIG. 13 is connected to terminal 951 and terminal 952.

[0252] The circuit board 900 has a terminal 911 and a circuit 912. The terminal 911 is connected to the terminal 95. 1, terminal 952, antenna 914, antenna 915, and circuit 912. 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, It can also be a child.

[0253] The circuit 912 may be provided on the back surface of the circuit board 900. The antenna 915 is not limited to a coil shape, but may be, for example, a wire shape or a plate shape. , Planar antenna, Aperture antenna, Traveling wave antenna, EH antenna, Magnetic field antenna, Dielectric Alternatively, an antenna such as a body antenna may be used. The flat conductor may be a flat conductor. This flat conductor functions as one of the conductors for electric field coupling. In other words, the capacitor has two conductors, one of which is an anode. The antenna 914 or the antenna 915 may be activated. Furthermore, electric power can be exchanged using an electric field.

[0254] The line width of antenna 914 is preferably larger than the line width of antenna 915. This allows the amount of power received by the antenna 914 to be increased.

[0255] The secondary battery is provided with a layer 916 between the antenna 914 and the antenna 915 and the secondary battery 913. The layer 916 has a function of shielding an electromagnetic field generated by the secondary battery 913, for example. The layer 916 may be made of, for example, a magnetic material.

[0256] The structure of the secondary battery is not limited to that shown in FIG.

[0257] 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.

[0258] 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.

[0259] 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.

[0260] 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.

[0261] 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.

[0262] 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.

[0263] 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.

[0264] Furthermore, an example of the structure of the secondary battery 913 will be described with reference to FIGS.

[0265] 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, 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.

[0266] 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.

[0267] 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 Antennas such as antenna 914 and antenna 915 may be provided inside the housing 930b. For example, a metal material can be used as the material.

[0268] 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.

[0269] 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.

[0270] 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.

[0271] [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.

[0272] 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.

[0273] 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. .

[0274] 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.

[0275] 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.

[0276] 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.

[0277] 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.

[0278] 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.

[0279] 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.

[0280] 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 .

[0281] 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.

[0282] 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.

[0283] 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.

[0284] 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.

[0285] 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.

[0286] [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.

[0287] 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.

[0288] Next, the negative electrode 506 , the separator 507 and the positive electrode 503 are placed on the exterior body 509 .

[0289] 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.

[0290] 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.

[0291] 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.

[0292] [Bendable secondary battery] Next, an example of a bendable secondary battery will be described with reference to FIGS. 16 and 17. do.

[0293] FIG. 16A shows a schematic top view of a bendable secondary battery 250. 16B2 and 16C are cut along the lines C1-C2 and C3-C4 in FIG. 16A, respectively. The secondary battery 250 is a schematic cross-sectional view taken along the line A1-A2. and an electrode stack 210 housed inside the body 251. The electrode stack 210 includes at least At least the positive electrode 211a and the negative electrode 211b are stacked. a lead 212a electrically connected to the negative electrode 211b; b extends to the outside of the package 251. In addition, in the area surrounded by the package 251, In addition to 211a and negative electrode 211b, an electrolyte (not shown) is enclosed.

[0294] 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.

[0295] 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.

[0296] 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 is formed are in contact with each other. will be done.

[0297] In addition, the surface on which the positive electrode active material of the positive electrode 211a is formed and the surface on which the negative electrode active material of the negative electrode 211b is formed are A separator 214 is provided between the surfaces. The data 214 is shown by a dotted line.

[0298] 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.

[0299] Next, the exterior body 251 will be described with reference to FIGS. 16B1, 16B2, 16C, and 16D. Reveal.

[0300] 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.

[0301] 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.

[0302] FIG. 16B1 is a cross section cut at the part overlapping with the ridge line 271, and FIG. 16B2 is a cross section cut at the part overlapping with the valley line 271. 16B1 and 16B2 are cross sections cut at the part overlapping with the secondary battery 25. 0 and corresponds to the cross section in the width direction of the positive electrode 211a and the negative electrode 211b.

[0303] 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. .

[0304] 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.

[0305] 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.

[0306] 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.

[0307] 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.

[0308] FIG. 16C is a cross section including the lead 212a, and shows the secondary battery 250, the positive electrode 211a, and 16C, 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.

[0309] FIG. 16D 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.

[0310] 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.

[0311] Furthermore, as shown in FIG. 16D, 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.

[0312] 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.

[0313] 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.

[0314] (Embodiment 5) 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.

[0315] 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.

[0316] 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.

[0317] 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.

[0318] 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.

[0319] 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.

[0320] 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.

[0321] 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.

[0322] 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.

[0323] 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.

[0324] 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.

[0325] 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.

[0326] 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.

[0327] 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.

[0328] 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.

[0329] 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.

[0330] The display device 7300 is also provided 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.

[0331] 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.

[0332] 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.

[0333] 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.

[0334] 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.

[0335] 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.

[0336] 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.

[0337] 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.

[0338] 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

[0339] 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.

[0340] 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.

[0341] 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.

[0342] 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.

[0343] 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.

[0344] 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.

[0345] 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.

[0346] 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.

[0347] 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.

[0348] 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.

[0349] 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.

[0350] 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.

[0351] 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:

[0352] 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.

[0353] 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, the side wall 8105, the floor 8106, and the like are not included in the ceiling 8104. 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.

[0354] 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.

[0355] 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.

[0356] 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.

[0357] 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.

[0358] Among the above-mentioned electronic devices, high-frequency heating devices such as microwave ovens and electric rice cookers The sub-devices require high power for a short period of time, so the power that cannot be supplied by the commercial power supply is supplemented. By using a secondary battery according to one embodiment of the present invention as an auxiliary power source for supporting This can prevent the commercial power breaker from tripping when using the

[0359] 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.

[0360] 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 above-mentioned in the electronic device, it is possible to make the electronic device lighter and with a longer life span. This embodiment can be implemented in appropriate combination with other embodiments.

[0361] (Embodiment 6) 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.

[0362] When a secondary battery is installed in a vehicle, it becomes a hybrid vehicle (HV), an electric vehicle (EV), or a powertrain. This will enable the realization of next-generation clean energy vehicles such as plug-in hybrid vehicles (PHVs).

[0363] 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 one embodiment of the present invention, it is possible to realize a hybrid vehicle with a long driving range. The vehicle 8400 can be realized. The automobile 8400 also has a secondary battery. The secondary battery is The secondary battery modules shown in Figures 6C and 6D are arranged on the floor of the vehicle. In addition, a battery pack consisting of multiple secondary batteries as shown in Figure 9 can be installed on the floor of the vehicle. The secondary battery not only drives the electric motor 8406 but also It can supply power to light emitting devices such as light 8401 and room lights (not shown). do.

[0364] 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.

[0365] 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 mounted on the automobile 8500 can be charged by the power supply. This can be done by converting AC power to DC power via a conversion device such as an AC / DC converter. can.

[0366] 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.

[0367] 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. .

[0368] 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.

[0369] 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.

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

[0371] (Embodiment 7) 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.

[0372] FIG. 22A shows an example of a wearable device. In addition, the user must be able to use the device in daily life or outdoors without being exposed to water. To improve the reliability, we have implemented wireless charging in addition to wired charging, where the connector is exposed. There is a demand for wearable devices that can also be charged.

[0373] 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.

[0374] 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.

[0375] 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.

[0376] 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.

[0377] It can also be mounted on a belt-type device 406. The belt-type device 406 includes: The belt portion 406a and the wireless power receiving portion 406b are included. A secondary battery can be mounted on the

[0378] 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.

[0379] The display unit 405a displays not only the time but also various information such as incoming emails and phone calls. It is possible.

[0380] 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.

[0381] The wristwatch type device 405 shown in FIG. 22A will be described in detail below.

[0382] FIG. 22B shows a perspective view of the wristwatch type device 405 removed from the wrist.

[0383] 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.

[0384] This embodiment mode can be implemented in appropriate combination with other embodiment modes. [Example]

[0385] In this example, the positive electrode active material was prepared using the DSC test described in the previous embodiment. We conducted an examination of the substances used.

[0386] Using the method shown in FIG. 1A, Sample 1, which is a mixture of substance 91 and substance 92, Lithium fluoride was used as substance 91 and magnesium fluoride was used as substance 92. The magnesium in magnesium fluoride is The molar ratio of lithium in the aluminum was 0.33. Used.

[0387] Next, using the method shown in FIG. 1C, substances 91 to 94 were examined. Lithium fluoride as substance 91, magnesium fluoride as substance 92, nickel hydroxide as substance 93 Aluminum hydroxide was used as Substance 91, Substance 92, and Substance 94, respectively. The mixture of 3 and substance 94 is called Sample 2. In Sample 2, The molar ratio of magnesium in magnesium fluoride to lithium in lithium fluoride The amount of nickel in nickel hydroxide is 0.33 times that of aluminum hydroxide. The aluminum content was adjusted to 0.5 times that of the original. DSC was used as the inspection method.

[0388] Temperature of Sample 1 and Sample 2 measured by DSC The heat flow curve is shown in Figure 23A. A peak indicating an endothermic reaction was observed around 730°C, and the reaction It is thought that a eutectic reaction of magnesium occurs. No significant peaks suggesting an endothermic reaction are observed around ℃. Any of the substances 94 may tend to inhibit the endothermic reaction.

[0389] Also, Figure 23B shows the DSC temperature-heat flow curve for Sample 1. Figure 23C shows the differential waveform of the heat flow curve of Sample 2. The differential waveforms of the temperature-heat flow curves are shown in Fig. 1. A maximum and minimum point were observed around 730°C where the peak was observed. In 2, no significant peak was observed or was extremely weak.

[0390] Next, a mixture of Sample 1 and nickel hydroxide was named Sample 3. The mixture of le 1 and aluminum hydroxide was named Sample 4. DSC was performed on the nickel hydroxide in Sample 3. The mole ratio of nickel in magnesium fluoride is 0.5 times the mole ratio of magnesium in magnesium fluoride. In Sample 4, the aluminum contained in the aluminum hydroxide was The molar ratio of magnesium in magnesium fluoride is set to 0.5 times the molar ratio of magnesium in magnesium fluoride. The differential waveform of the DSC of Sample 3 is shown in Figure 24A, and the differential waveform of the DSC of Sample 4 is shown in Figure 24B. The waveforms are shown in Figure 24B. It can be seen that the peak suggesting endothermic activity around 730°C becomes smaller. In e4, a peak indicating an exothermic reaction was observed around 500°C, suggesting crystallization or magma. There is a possibility that reactions such as the production of compounds by reaction with nesium, etc. Aluminum hydroxide may be the inhibitor of the endothermic reaction between lithium fluoride and magnesium fluoride. This is a possibility.

[0391] When the method of FIG. 2B or FIG. 2C is used as the method of producing the positive electrode active material, the method of FIG. 2A is different from the method of FIG. It was suggested that a positive electrode active material of even higher quality could be obtained in this case.

[0392] Next, the mixture of substance 91 and substance 92 (Sample 1) was further treated with metal oxide 9 5, lithium cobalt oxide was added and mixed to prepare Sample 5. This shows the differential waveform of the DSC of Sample 5. By adding lithium cobalt oxide, The peak indicating endothermic activity observed by DSC at around 730°C is about 100°C on the positive side. I found that it shifts. [Example]

[0393] In this example, a positive electrode active material was manufactured by the manufacturing method described in the previous embodiment. In order to evaluate the characteristics of the positive electrode using the positive electrode active material, a secondary battery was fabricated.

[0394] Three secondary batteries, Cell 1, Cell 2, and Cell 3, were fabricated.

[0395] The positive electrode active material used in Cell 1 was prepared using the method shown in Figure 2B. More specifically, the method shown in FIG. 3 was used. Lithium fluoride was used as the substance 91, and Magnesium fluoride was used as the ion exchanger. The molar ratio of substance 91 to substance 92 was e 1. The powder weight of Mixture 904 was 30 g.

[0396] The positive electrode active material used in Cell 2 and Cell 3 was prepared by the method shown in Figure 2A. The electrode active materials were prepared. Material 91 was lithium fluoride, and material 92 was magnesium fluoride. Nickel hydroxide was used as material 93, and aluminum hydroxide was used as material 94. The molar ratio of substance 91 to substance 92 was determined by referring to Sample 1. The molar ratio of nickel in magnesium fluoride is 0.5 times the molar ratio of magnesium in magnesium fluoride. The aluminum hydroxide has a molar ratio of magnesium fluoride. The molar ratio of magnesium in the material was set to 0.5 times the molar ratio of magnesium in the material. The total weight of the powder was 30 g for Cell 2 and 2.4 g for Cell 3.

[0397] Cell 1, Cell 2 and Cell 3 are CR2032 type (diameter 2 A coin-type secondary battery (diameter 1.0 mm, height 3.2 mm) was fabricated.

[0398] The positive electrode was made of the positive electrode active material prepared above, acetylene black (AB), and polyfluoride. The positive electrode active material was mixed with PVDF in a ratio of AB:PVDF=95:3:2 (by weight). The combined slurry was applied to a current collector.

[0399] The counter electrode was made of lithium metal.

[0400] 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.

[0401] The separator was made of polypropylene with a thickness of 25 μm.

[0402] The positive electrode can and the negative electrode can were made of stainless steel (SUS).

[0403] [Cycle characteristics] The secondary battery was charged at 45°C using CCCV (0.5C, 4.6V, The battery was repeatedly charged and discharged at CC (0.5C, 2.5V) and the final current was 0.05C. The cycle characteristics were evaluated.

[0404] The results of the cycle characteristics of each secondary battery are shown in Figure 26. Regarding aluminum hydroxide, which is thought to be likely to inhibit the eutectic reaction of magnesium, In the preparation method of 3, that is, in the preparation of the mixture to be annealed for the second time, aluminum hydroxide In Cell 1, which has a positive electrode active material prepared by the method adding Compared to the manufacturing method using aluminum hydroxide in the cell, the cycle characteristics are superior. It was also shown that when aluminum hydroxide was added in the first annealing, It was shown that a lower powder weight during annealing resulted in better properties. [Example]

[0405] In this example, the positive electrode active material was prepared using the XRD test described in the previous embodiment. We conducted an examination of the substances used.

[0406] Sample 2, Sample 3 and Sample 4 prepared in the previous example After heat treatment at 850°C in an oxygen atmosphere, each sample was evaluated by XRD. The spectra of D are shown in Figures 27, 28, 29 and 30. The vertical axis of Figures 27 to 30 The horizontal axis shows the intensity of the spectrum, and the horizontal axis shows 2θ. The graphs in FIG. 30 have different ranges of 2θ indicated on the horizontal axis.

[0407] For the XRD measurement, a Bruker D8ADVANCE was used. The X-ray output was set to 40 kV and 40 mA, and the scanning angle was set to the range of 15° to 90°. The measurement interval was 0.01°, the scanning speed was 0.5 sec / step, and the sample was scanned for 15 r The measurements were taken while rotating at 1000 rpm.

[0408] The obtained XRD patterns were analyzed using DIFFRAC.EVA (Bruker XRD data analysis software). Analysis software was used to remove background and Kα2.

[0409] Based on the XRD results of Sample 2, the peak positions of the main peaks were calculated. k position, half width and peak intensity The peak intensity is shown in Table 1. Here, the peak position is the maximum value of the peak. Although not shown in Table 1, an intensity of about 37 was observed at a position of 37.03°.

[0410] [Table 1]

[0411] In Sample 2, 2θ is 19.08°, 31.44°, 59.60°, etc. MgAl with spinel structure (2-x) Ni x Possibility corresponding to O4 (x is 0 to 2) These peaks were also observed to be significantly smaller than the peak at 40.43°. The peak intensities were 0.05, 0.04, and 0.06 times, respectively.

[0412] From the results of Figures 27 to 30 and Table 1, it can be seen that the magnesium in magnesium fluoride and the water The aluminum in aluminum oxide may have reacted to produce a product. The formation of this substance may have weakened the eutectic reaction between lithium fluoride and magnesium fluoride. There is a gender.

[0413] Next, XRD measurement was carried out on the positive electrode active material used in Cell 2 shown in Example 2. The spectra are shown in Figures 43A, 43B, 44A and 44B. The vertical axis of Figures 44A and 44B represents the intensity of the spectrum. The horizontal axis represents 2θ. The range of 2θ shown on the horizontal axis differs.

[0414] For the XRD measurement, a Bruker D8ADVANCE was used. The X-ray output was set to 40 kV and 40 mA, and the scanning angle was set to the range of 15° to 90°. The measurement interval was 0.01°, the scanning speed was 5 sec / step, and the sample was rotated at 15 rpm. The measurement was carried out while rotating the sensor.

[0415] The obtained XRD patterns were analyzed using DIFFRAC.EVA (Bruker XRD data analysis software). Analysis software was used to remove background and Kα2.

[0416] Based on the obtained XRD results, the peak positions of the main peaks were determined. n), half width and peak intensity y) are shown in Table 2. Here, the peak position was taken as the maximum value of the peak.

[0417] [Table 2]

[0418] This is suggested to be due to the spinel structure suggested by the XRD of Sample 2 above. As described in the first embodiment, the peak was not clearly observed. The peak due to 5 was strong, and a peak suggesting that it was due to a spinel structure was observed. It may be difficult to do so. [Example]

[0419] In this example, a positive electrode active material was prepared using the method shown in FIG. 2B, more specifically, the method shown in FIG. The initial charge-discharge characteristics, high-voltage cycle characteristics, high-temperature cycle characteristics, and continuous charge characteristics were measured. Evaluated.

[0420] Using the method shown in Figure 3, when the number of cobalt atoms in lithium cobalt oxide is 1, The molar concentration of nickel is 0.005, the molar concentration of aluminum is 0.005, and the molar concentration of magnesium is The positive electrode active material prepared so that the molar concentration of was 0.01 was designated as Sample 6. The mixing ratio of magnesium fluoride and lithium fluoride is LiF:MgF2=1:3 (molar ratio). The first annealing (Fig. 3S34) was performed at 900°C for 20 hours, and the second annealing (Fig. 3 S56) was carried out at 850°C for 10 hours in an oxygen atmosphere (oxygen gas flow rate 10 L / min). Ta.

[0421] Magnesium fluoride and lithium fluoride were added to lithium cobalt oxide and annealed once. The positive electrode active material was Sample 7. The number of cobalt atoms in lithium cobalt oxide was When the molar concentration of magnesium is set to 1, the molar concentration of magnesium is set to 0.005. The mixing ratio of lithium fluoride and lithium fluoride was LiF:MgF2 = 1:3 (molar ratio). The annealing was carried out at 900°C for 20 hours in an oxygen atmosphere (the heating furnace was purged with oxygen gas before annealing). went.

[0422] Lithium cobalt oxide without other element additions and annealing was used as Sample 8 (comparison example). It was decided.

[0423] Using the positive electrode active materials of Samples 6 to 8, coin cells were fabricated. The mixture ratio of the positive electrode active material, conductive additive and binder, the electrolyte, the electrolyte solution, the separator, the positive electrode can and The negative electrode can was the same as in Example 2.

[0424] <Initial charge / discharge characteristics at charging voltages of 4.60V, 4.62V, 4.64V, and 4.66V Cycle characteristics> Using the coin cell, charging voltages were set to 4.60 V, 4.62 V, 4.64 V, and 4 The cycle characteristics were evaluated at 25°C and 45°C. CCCV (100mA / g, various voltages, final current 10mA / g), discharge CC (100 The battery was repeatedly charged and discharged at a constant current of 2.5 V (mA / g, cut-off voltage 2.5 V).

[0425] Figure 31A shows the cycle characteristics at 25°C and a charging voltage of 4.60V. 32A shows the cycle characteristics at 25°C and a charge voltage of 4.60V. Figure 32B shows the cycle characteristics at 45°C and a charging voltage of 4.62V. Figure 33A shows the cycle characteristics at 25°C and a charging voltage of 4.64V. Figure 33B shows the cycle characteristics at 45°C and a charging voltage of 4.64V. 34B shows the cycle characteristics at 45°C and a charge voltage of 4.66V. The cycle characteristics at 6V are shown.

[0426] Table 3 shows the initial charge capacity and initial discharge capacity at 25°C or 45°C and each charge voltage. It is the capacity per weight of active material, and the unit is mAh / g.

[0427] [Table 3]

[0428] As is clear from FIGS. 31 to 34, the sample without adding other elements and annealing is Compared with e8, Sample 6 and Sample 7 have very good cycle characteristics. At 25°C and a charging voltage of 4.6V, Sample 6 and Sample There is no significant difference between Sample 7, but as the temperature and voltage increase, the size of Sample 6 The curve characteristics tended to be better.

[0429] From Table 3, it is clear that Sample 8 has a large irreversible capacity due to the initial charge / discharge. As the temperature and voltage increased, the irreversible capacity tended to increase. In contrast, Sample 6 and Sample 7 exhibited good characteristics with little irreversible capacity. Ta.

[0430] <Cycle characteristics at 25℃, 45℃, 50℃, 55℃ and 60℃> Next, coin cells were fabricated using the positive electrode active materials of Samples 6 to 8. The cycle characteristics were evaluated at 25°C, 45°C, 50°C, 55°C and 60°C using Specifically, at each temperature, charging was performed using CCCV (100mA / g, 4.6V, final current Repeated charge and discharge at CC (100mA / g, final voltage 2.5V). went.

[0431] Figure 35A shows the cycle characteristics of Sample 6 at each temperature. The initial charge-discharge curve and the 50th charge-discharge curve at a voltage of 4.60 V are shown in Figure 36A. Figure 36B shows the cycle characteristics of Ple 7 at various temperatures. The initial charge-discharge curve and the 50th charge-discharge curve are shown in Fig. 37A. The cycle characteristics at 50°C and a charge voltage of 4.60V are shown in Fig. 37B. The line and the 50th charge / discharge curve are shown.

[0432] As is clear from Figures 35 to 37, at any temperature, the results are comparable to Sample 8. In comparison, Sample 6 and Sample 7 showed good cycle characteristics. Sample 6, which has nickel and aluminum, was heated to 25°C, 45°C, and 50°C. As shown in the discharge curve of FIG. 35B, the cycle characteristics were extremely good. The discharge voltage remained high even at a voltage of 4.60 V and 50°C.

[0433] For Sample 6, the initial discharge capacity was 220.0 mA / The discharge capacity at the 50th cycle was 204.0 mA / g, and the decrease in discharge capacity was less than 8%. At a charging voltage of 4.6 V and 50°C, the initial discharge capacity was 223.1 mA / g. The discharge capacity at the 50th cycle was 191.9 mA / g, and the decrease in discharge capacity was less than 14%. The decrease rate was as follows: the discharge capacity at the first cycle was 100%, and the decrease rate was This number represents the decrease in capacity in the second cycle from the discharge capacity in the first cycle.

[0434] <Continuous charging test> Next, coin cells were fabricated using the positive electrode active materials of Samples 6 to 8. A continuous charging test was conducted using a secondary battery at a constant voltage for a long period of time. This test involves charging the battery and evaluating its stability and safety.

[0435] First, one cycle of charge and discharge was performed, followed by continuous charging. The first charge and discharge was performed using CCCV ( 38mA / g, 4.5V, end current 4mA / g), discharge is CC (38mA / g, end voltage The continuous charging was performed at CCCV (96 mA / g, 4.60 V, 4.6 The test was performed at 60°C (2V, 4.64V or 4.66V). The test was measured for up to 250 hours. did.

[0436] 38A to 38C show the results for a voltage of 4.60 V, and the horizontal axis shows the charging time (Charge The vertical axis indicates voltage or current. Figure 38A shows Sample 6, Figure 38B shows Sample 7, and Figure 38C shows Sample e 8 shows the results of the continuous charging test.

[0437] 39A to 39C show the results for a voltage of 4.62 V, and the horizontal axis shows the charging time (Charge The vertical axis indicates voltage or current. Similarly, Sample 6 is shown in Figure 39A, Sample 7 in Figure 39B, and Sample 8 in Figure 39C. The results of the continuous charging test of the ample 8 are shown below.

[0438] 40A to 40C show the results for a voltage of 4.64 V, and the horizontal axis shows the charging time (Charge The vertical axis indicates voltage or current. Similarly, Sample 6 is shown in Figure 40A, Sample 7 in Figure 40B, and Sample 8 in Figure 40C. The results of the continuous charging test of the ample 8 are shown below.

[0439] 41A to 41C show the results for a voltage of 4.66 V, and the horizontal axis shows the charging time (Charge The vertical axis indicates voltage or current. Similarly, Sample 6 is shown in Figure 41A, Sample 7 in Figure 41B, and Sample 8 in Figure 41C. The results of the continuous charging test of the ample 8 are shown below.

[0440] As shown in FIGS. 38 to 41, Sample 8, which is a comparative example, exhibits a relatively low voltage at 4.6 V. While stable continuous charging characteristics were demonstrated, the battery showed no signs of deterioration within 200 hours at 4.62V or higher. An increase in current was observed, which was thought to be due to the

[0441] On the other hand, Sample 6 exhibits stable continuous charging characteristics as the voltage increases, and It has been revealed that the safety is extremely high even under high temperature and high voltage conditions of 4.62V or more. It became.

[0442] Next, the endurance time of the secondary battery was calculated from Figures 38 to 41. The horizontal axis of Figure 42 represents charging time, and the vertical axis represents Indicates voltage or current.

[0443] Endurance time T E is the short circuit time T S CC charging completion time T F The short circuit time is reduced. T S is the approximate line L1 during the period when a stable low current is maintained after the start of CV charging, and the short The time and the intersection point P of the approximate line L2, which is the period during which the current rise thought to be due to did.

[0444] The endurance times of Samples 6 to 8 are shown in Table 4. The unit is hours.

[0445] [Table 4]

[0446] As shown in Table 4, Sample 6 had a durability of over 200 hours under all conditions. In particular, the endurance time was 250 hours at charging voltages of 4.62V, 4.64V, and 4.66V. This demonstrates that the device is extremely safe even at high temperatures and high voltages. [Explanation of symbols]

[0447] SW1: Switch, SW2: Switch, SW3: Switch, 78i: Current, 81: Mixture , 91: Substance, 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, 2 12b: Lead, 214: Separator, 215a: Joint, 215b: Joint, 217: Fixing member, 250: secondary battery, 251: exterior body, 261: bent portion, 262: sealing portion 263: Sealing portion, 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 assembly Electric body, 306: Positive electrode active material layer, 307: Negative electrode, 308: Negative electrode current collector, 309: Negative electrode active material Layer, 310: separator, 400: eyeglass-type device, 400a: frame, 400b: surface display unit, 401: headset type device, 401a: microphone unit, 401b: flexible Pipe, 401c: earphone part, 402: device, 402a: housing, 402b: secondary Battery, 403: device, 403a: housing, 403b: secondary battery, 405: wristwatch type device Chair, 405a: display unit, 405b: belt unit, 406: belt-type device, 406a: Belt part, 406b: wireless power receiving part, 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, 5 06: negative electrode, 507: separator, 508: electrolyte, 509: outer casing, 510: positive electrode lead 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 terminal, 608: insulating plate, 609: insulating plate, 611: PTC element, 612: safety valve structure, 613: conductive plate, 614: conductive plate, 615: module, 616: conductor, 617: temperature Degree control device, 900: circuit board, 902: mixture, 903: mixture, 904: mixture, 9 05:Mixture, 906:Mixture, 907:Mixture, 908:Mixture, 909:Mixture, 9 10: Label, 911: Terminal, 912: Circuit, 913: Secondary battery, 914: Antenna, 9 15: Antenna, 916: Layer, 917: Layer, 918: Antenna, 920: Display device, 92 1: sensor, 922: terminal, 930: housing, 930a: housing, 930b: housing, 931: Negative electrode, 932: positive electrode, 933: separator, 950: wound body, 951: terminal, 952: terminal Child, 980: secondary battery, 981: film, 982: film, 993: wound body, 994 : 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 , 7104: Secondary battery, 7200: Portable information terminal, 7201: Housing, 7202: Display unit, 7203: Band, 7204: Buckle, 7205: Operation buttons, 7206: Input / output terminals , 7207: Icon, 7300: Display device, 7304: Display unit, 7400: Mobile phone , 7401: Housing, 7402: Display unit, 7403: Operation buttons, 7404: External connection port 7405: Speaker, 7406: Microphone, 7407: Secondary battery, 7500: Electronic cigarette Ko, 7501: atomizer, 7502: cartridge, 7504: secondary battery, 8000: Display device, 8001: housing, 8002: display unit, 8003: speaker unit, 8004: secondary Battery, 8021: Charging device, 8022: Cable, 8024: Secondary battery, 8100: Lighting Device, 8101: Housing, 8102: Light source, 8103: Secondary battery, 8104: Ceiling, 810 5: Side wall, 8106: Floor, 8107: Window, 8200: Indoor unit, 8201: Housing, 8202 : Air outlet, 8203: Secondary battery, 8204: Outdoor unit, 8300: Electric refrigerator / freezer, 830 1: Housing, 8302: Refrigerator door, 8303: Freezer door, 8304: Secondary battery, 840 0:Automobile, 8401:Headlight, 8406:Electric motor, 8500:Automobile, 8 600: Scooter, 8601: Side mirror, 8602: Secondary battery, 8603: Direction indicator Light, 8604: Under-seat storage, 9600: Tablet terminal, 9625: Switch, 962 6: Switch, 9627: Switch, 9628: Operation switch, 9629: Fastener, 96 30: Housing, 9630a: Housing, 9630b: Housing, 9631: Display unit, 9631a: Table display unit, 9631b: display unit, 9633: solar cell, 9634: charge / discharge control circuit, 9635 : Storage battery, 9636: DCDC converter, 9637: Converter, 9640: Moving part< / xrd> < / dsc>

Claims

[Claim 1] A secondary battery having a positive electrode active material, the positive electrode active material contains lithium and magnesium, the positive electrode active material contains one or more of cobalt, nickel, and manganese, The positive electrode active material has a layered rock salt structure, The positive electrode active material has a structure represented by the space group R-3m, The battery is charged and discharged 50 times at a charging voltage of 4.60 V and a temperature of 50° C., and the decrease in discharge capacity at the 50th cycle from the first cycle is 14% or less, assuming that the discharge capacity at the first cycle is 100%. Secondary battery.

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