Method for producing positive electrode active material

Abstract

To provide a manufacturing method capable of improving powder physical properties while improving load resistance such as a rate and output resistance in utilization as a positive electrode active material used for a lithium ion secondary battery, and capable of shortening a manufacturing tact and reducing cost.SOLUTION: In order to perform the heat treatment at a temperature lower than the melting point of magnesium fluoride, lithium fluoride is mixed to melt magnesium fluoride, thereby modifying the surface of the lithium cobalt oxide powder. By mixing lithium fluoride, magnesium fluoride can be melted at a temperature lower than the melting point, and a positive electrode active material is manufactured by utilizing this eutectic phenomenon.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] In this specification, the term "power storage device" refers to elements and devices in general that have a power storage function. For example, lithium-ion secondary batteries and other storage batteries (also called secondary batteries) These include lithium-ion capacitors, all-solid-state batteries, 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 such as lithium-ion secondary batteries, lithium-ion capacitors, and air batteries have become available. In particular, lithium-ion batteries, which have high output and high energy density, are being developed. The secondary battery is used in mobile phones, smartphones, tablets, or laptop computers. Portable information terminals, portable music players, digital cameras, medical equipment, or hybrid vehicles ( HEV), electric vehicle (EV), or plug-in hybrid vehicle (PHEV), etc. Demand is expanding rapidly along with the development of the semiconductor industry, including next-generation clean energy vehicles. As a source of rechargeable energy, they have become indispensable in today's information society.

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

[0006] In particular, since a high voltage of 4V can be obtained, it is suitable as a positive electrode active material for lithium-ion secondary batteries. Lithium baltic oxide (LiCoO2) is widely used.

[0007] As a secondary battery for driving motors in electric vehicles, etc., it is more powerful than mobile phones and laptops. Therefore, high output characteristics, high energy density, and stable cycle characteristics are required. In addition, the secondary battery for driving the motor is a rapid charger that can be completed in a short time. There is also a demand for it to be rechargeable.

[0008] Positive electrode active material aiming at improving cycle characteristics and increasing capacity of lithium-ion secondary batteries Improvements have been investigated (Patent Documents 1 and 2). Research into this issue is also being conducted (Non-Patent Documents 1 to 4).

[0009] 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.

[0010] Patent Document 3 describes the Jahn-Teller effect in nickel-based layered oxides. There are.

[0011] Patent Document 4 has developed a positive electrode active material in which the crystal structure changes little between the charged and discharged states. is shown. [Prior art documents] [Patent documents]

[0012] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-216760 [Patent Document 2] Japanese Patent Application Laid-Open No. 2006-261132 [Patent Document 3] Japanese Patent Application Laid-Open No. 2017-188466 [Patent Document 4] International Publication No. 2018 / 211375 [Non-patent literature]

[0013] [Non-Patent Document 1] Toyoki Okumura et al, “Correlation of lithium ion distribution and X-ray absorption near-edge structure in O3-and O2-lithium cobalt oxides from first-principle calculation”, Journal of Materials Chemistry, 2012, 22, p.17340-17348 [Non-patent document 2] Motohashi, T. et al, “Electronic phase diagram of the layered cobalt oxide system LixCoO2(0.0≦x≦1.0)”, Physical Review B, 80(16);165114 [Non-patent document 3] Zhaohui Chen et al, “Staging Phase Transitions in LixCoO2”, Journal of The Electrochemical Society, 2002, 149(12) A1604-A1609 [Non-patent document 4] WE Counts et al, “Fluoride Model Systems:II, The Binary Systems CaF2-BeF22, MgF2-BeF2, and LiF-MgF2” Journal of the American Ceramic Society, (1953) 36[1] 12-17. Fig.01471 [Non-Patent Document 5] Belsky, A. et al., “New developments in the Inorganic Crystal Structure Database (ICSD): accessibility in support of materials research and design”, Acta Cryst., (2002) B58 364-369. Summary of the Invention [Problem to be solved by the invention]

[0014] If the charging voltage applied to the secondary battery can be increased, the time that it can be charged at a high voltage will be extended, and the unit The amount of charge per hour increases, shortening the charging time. In the field of electrochemical cells, when the voltage exceeds 4.5 V, Battery deterioration occurs.

[0015] Increasing the charging voltage applied to a secondary battery causes side reactions that significantly reduce battery performance. A side reaction is a reaction product that occurs when the active material or electrolyte undergoes a chemical reaction. This refers to the promotion of the formation or oxidation or decomposition of the electrolyte. Gas evolution and volume expansion may occur.

[0016] An object of one embodiment of the present invention is to provide a high-capacity secondary battery. Another object of the present invention is to provide a secondary battery with excellent charge-discharge characteristics. An object of one embodiment is to provide a secondary battery with high safety or reliability.

[0017] The capacity retention rate when repeatedly charging and discharging at a charging voltage of 4.5V or higher, preferably 4.6V or higher Another object of the present invention is to provide a positive electrode active material that can be improved and a method for producing the same.

[0018] Another embodiment of the present invention is a novel substance, active material particles, a secondary battery, or a manufacturing method thereof. One of our goals is to provide the following.

[0019] Specifically, one embodiment of the present invention is a method for producing a lithium ion secondary battery using a cathode active material. In this application, we have improved the powder properties while also improving load resistance such as rate and output resistance. Furthermore, the objective is to provide a manufacturing method that can shorten the manufacturing takt time and reduce costs. This is one of the topics.

[0020] The description of these problems does not preclude the existence of other problems. It is not necessary for the embodiments to solve all of these problems. It is possible to extract other problems from the description of the claim. [Means for solving the problem]

[0021] One aspect of the present invention is a method for producing a nickel-containing oxide comprising: magnesium fluoride, lithium fluoride, a nickel source, and aluminum. and a lithium source, which are each finely pulverized and then mixed with lithium cobalt oxide powder to form a first mixture. and a second step of heating the lithium cobalt oxide at a temperature lower than the heat-resistant temperature of the lithium cobalt oxide. and a second step of preparing a mixture of the above.

[0022] In this specification, the heat resistance temperature of lithium cobalt oxide is set to 1000°C. The melting point of lithium valence oxide is 1130°C, and Li begins to evaporate from just below that temperature, at around 1000°C. and cation mixing of Li and Co., etc., occurs easily. When cooling, it is desirable to keep the temperature below 1000°C. In order to perform the heat treatment at a temperature lower than 63°C, lithium fluoride (melting point 848°C) is mixed. By combining the magnesium fluoride and the lithium cobalt oxide powder, the surface of the powder is modified. By mixing lithium fluoride, magnesium fluoride melts at a temperature lower than its melting point. This eutectic phenomenon can be utilized to produce the positive electrode active material. Differential scanning calorimetry (DSC) or differential thermal analysis (DTA) or simultaneous differential thermal and thermogravimetry ( Measured using SDT.

[0023] Secondary batteries using positive electrode active materials manufactured using the eutectic phenomenon can achieve a charging voltage of 4.5V or higher. Preferably, the voltage is set to 4.6 V or higher to prevent battery deterioration.

[0024] In addition, by modifying the surface of the lithium cobalt oxide powder, a manufacturing process with low heating temperatures is provided. Providing a manufacturing process with a low heating temperature will reduce manufacturing costs. Connect.

[0025] In addition, in order to provide a manufacturing process with a low heating temperature, the nickel source and aluminum source are also melted. Use hydroxides with low melting points. Specifically, aluminum hydroxide (melting point 300°C) and hydroxide Nickel hydroxide (melting point 230°C) is used. The kel can co-melt near the eutectic point.

[0026] Furthermore, reducing the number of heat treatments also leads to a reduction in manufacturing costs. In this case, the heat treatment is performed once. The heat treatment conditions are below 1000°C, preferably The heating temperature is preferably 700°C or higher and 950°C or lower, and more preferably about 850°C. It is preferable that the time is 1 hour or more and 80 hours or less.

[0027] In the above manufacturing method, the heat treatment is performed once, but it is not particularly limited, and it may be performed up to two times. The heat treatment may be carried out twice or more times. Another composition is a mixture of magnesium fluoride and lithium fluoride, which are then pulverized into fine powders and then mixed with lithium cobalt oxide. A first step of mixing lithium cobalt oxide powder with lithium cobalt oxide powder to form a first mixture, A second step of heating the nickel source at a temperature below the thermal temperature to form a second mixture. a third step of pulverizing the powder and then mixing it with the second mixture to form a third mixture; After mixing the aluminum source into the mixture, the mixture is heated at a temperature below the heat resistance temperature of the lithium cobalt oxide. and a fourth step of preparing a fourth mixture by adding the above-mentioned components.

[0028] The heating temperature in the above two heat treatments is less than 1000°C, preferably 700°C or higher and 95°C or lower. It is preferable that the heating temperature is 0°C or lower and the heating time is 2 hours or more and 80 hours or less.

[0029] In the above manufacturing method, for example, the first heat treatment is performed at 900° C. for 20 hours, and then the second heat treatment is performed. If the first heat treatment is performed at 850°C for 2 hours, the total time required for heat treatment can be reduced. The above manufacturing method can be used without using a nickel source or aluminum source because magnesium fluoride has the highest melting point. The production flow is such that a sufficient reaction is carried out in advance to obtain a mixture before adding the aluminum source. I can say.

[0030] In each of the above-mentioned production methods, the aluminum source is not limited to hydroxide, and aluminum Aluminum isopropoxide can also be used. It is a type of nium alkoxide and can be expressed as Al[OCH(CH3)2]3. Aluminum isopropoxide is easily soluble in isopropanol and ethanol, but is easily dissolved in water. Disassemble.

[0031] In this specification, the eutectic point is the point at which two components become solid on the solid-liquid phase curve of the two components. This refers to the point at which materials are completely dissolved and mixed in a liquid state without forming a solution.

[0032] For example, when two metal elements A and B dissolve, A and B do not form a solid solution but remain as separate solids. A and B may form a phase or a molecular compound, and in the liquid phase, A and B may be completely soluble. A mixture of A and B has a melting point lower than that of A or B alone, and at a certain concentration ratio of A and B, When the mixture has the same melting point as the eutectic mixture, the lowest melting point is shown. It is not limited to two components, but may be three, four, or five or more components. good.

[0033] Lithium fluoride lowers the melting point of magnesium fluoride by adding it. It can also be said to be a co-melting agent for lithium fluoride (LiF) and magnesium fluoride (MgF2). The molar ratio is preferably LiF:MgF2=x:1 (0≦x≦1.9), and LiF :MgF2=x:1 (0.1≦x≦0.5) is more preferable, LiF:MgF2=x:1 (x=near 0.33) is more preferable. The value must be greater than 0.9 and less than 1.1.

[0034] If the amount of the co-melting agent used is greater than the above range, no effect will be obtained, and the co-melting agent will become an impurity. This will remain as it is, and when a secondary battery is fabricated, the battery characteristics will be deteriorated.

[0035] The secondary battery using the positive electrode active material obtained by the above-mentioned manufacturing method has a charging voltage of 4.5 V or more, preferably Even if the voltage is set to 4.6V or higher, battery deterioration can be suppressed.

[0036] The positive electrode active material obtained by the above-described manufacturing method is an oxide containing lithium and cobalt. The positive electrode active material of one embodiment of the present invention is represented by, for example, the space group R-3m.

[0037] In addition, the positive electrode active material of one embodiment of the present invention has a low reactivity, particularly when the depth of charge is deep. It preferably has a spinel structure.

[0038] In addition, the concentration of halogens such as fluorine in the surface layer of the positive electrode active material is higher than the average concentration of the whole particle. It is preferable that the halogen exists in the surface layer portion, which is the region in contact with the electrolyte, and therefore the hydrofluoric acid It is possible to effectively improve the corrosion resistance against

[0039] In this way, the surface layer of the positive electrode active material has a higher fluorine concentration than the inside, and has a different composition from the inside. It is preferable that the composition has a stable crystal structure at room temperature. Therefore, the surface layer may have a different crystal structure from the inside. At least a part of the surface layer may have a rock salt type crystal structure. When the crystal structure is different, it is preferable that the orientation of the crystals in the surface layer and the interior layer is roughly the same. It's nice.

[0040] The surface layer of the positive electrode active material contains at least element M, and also contains element A in the discharged state. It is necessary to have a path for insertion and desorption of element A. Element A acts as a carrier ion. Element A is, for example, an alkali metal such as lithium, sodium, or potassium, and and Group 2 elements such as calcium, beryllium, and magnesium.

[0041] The element M is, for example, a transition metal. Examples of the transition metal include cobalt, manganese, and nickel. The positive electrode material of one embodiment of the present invention can be, for example, a material containing an element M and at least one of the elements The alloy preferably contains one or more of cobalt, nickel, and manganese, and more preferably contains cobalt. In addition, it is preferable that the position of element M is replaced with a material such as aluminum that does not change the valence and is the same as element M. It may contain an element that can take a valence, more specifically, for example, a trivalent typical element.

[0042] Alternatively, one embodiment of the present invention is a positive electrode active material layer including any one of the above positive electrode active materials. The secondary battery has a positive electrode and a negative electrode supported on a current collector.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] In the present specification and the like, the pseudospinel type of the composite oxide containing lithium and a transition metal The crystal structure of this is in the space group R-3m, and is not a spinel-type crystal structure, but it is a cobalt-based Ions such as magnesium ions occupy the oxygen hexacoordinated positions, and the arrangement of cations is similar to that of spinel. It refers to a crystalline structure with symmetry. The pseudospinel type crystalline structure is characterized by the absence of light elements such as lithium. The atoms may occupy the oxygen tetracoordinate positions, and in this case the ionic arrangement is similar to that of the spinel type. It has symmetry.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] 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. [Effects of the Invention]

[0057] According to one aspect of the present invention, a lithium ion secondary battery having high capacity and excellent charge / discharge cycle characteristics is provided. Furthermore, it is possible to provide a positive electrode active material for a battery and a method for producing the same. It is also possible to provide a method for producing the material. This makes it 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 battery is kept in a high-voltage charged state for a long time, the cobalt It is possible to provide a positive electrode active material in which the elution of transition metals such as ZnO, Ni, and NiO is suppressed. It is possible to provide a highly reliable secondary battery. The present invention can provide a device or a method for making the same. [Brief explanation of the drawings]

[0058] [Figure 1] 1A to 1C illustrate an example of a method for manufacturing a positive electrode active material of one embodiment of the present invention. [Figure 2] 1A to 1C illustrate an example of a method for manufacturing a positive electrode active material of one embodiment of the present invention. [Figure 3] 1A to 1C illustrate an example of a method for manufacturing a positive electrode active material of one embodiment of the present invention. [Figure 4] FIG. 2 is a diagram illustrating the depth of charge and the crystal structure of a positive electrode active material. [Figure 5] FIG. 2 is a diagram illustrating the depth of charge and the crystal structure of a positive electrode active material. [Figure 6] 1(A) and 1(B) are cross-sectional views of an active material layer in which a graphene compound is used as a conductive additive. [Figure 7] 1A and 1B are cross-sectional views illustrating an example of a secondary battery of one embodiment of the present invention. [Figure 8] 1A and 1B are cross-sectional views illustrating an example of a secondary battery of one embodiment of the present invention. [Figure 9] 1A and 1B illustrate a manufacturing example of a secondary battery according to one embodiment of the present invention, and FIG. 1C is an enlarged cross-sectional view. [Figure 10] 1A is a perspective view illustrating an example of a secondary battery of one embodiment of the present invention, and FIG. 1B is a cross-sectional view. [Figure 11] 1A and 1B are diagrams illustrating a coin-type secondary battery, and 1C is a diagram showing a cross section of the battery during charging. [Figure 12] 1A, 1B, and 1C are perspective views illustrating a cylindrical secondary battery, and 1D is a top view. [Figure 13] 1A and 1B are diagrams illustrating an example of a secondary battery. [Figure 14] 1A, 1B, 1C, 1D, and 1E are diagrams illustrating examples of secondary batteries. [Figure 15] 1A and 1B are diagrams illustrating an example of a secondary battery. [Figure 16] FIG. 1 is a diagram illustrating an example of a secondary battery. [Figure 17] 1A, 1B, and 1C are perspective views illustrating a laminated secondary battery. [Figure 18] FIG. 1A is a top view illustrating a laminated secondary battery, and FIG. 1B is a cross-sectional view. [Figure 19] FIG. 1 is a diagram showing the appearance of a secondary battery. [Figure 20] FIG. 1 is a diagram showing the appearance of a secondary battery. [Figure 21] 1A, 1B, and 1C are diagrams illustrating a method for producing a secondary battery. [Figure 22] (A) is a top view illustrating a bendable secondary battery, and (B1), (B2), (C) and (D) are cross-sectional views. [Figure 23] 1(A) and 1(B) are diagrams illustrating a bendable secondary battery. [Figure 24] 1A and 1B illustrate an example of a secondary battery of one embodiment of the present invention and a manufacturing method thereof. [Figure 25] (A), (B), (D), (F), (G), and (H) are perspective views illustrating an example of an electronic device, and (C) and (E) are diagrams illustrating an example of a secondary battery. [Figure 26] 1A and 1B are diagrams illustrating an example of an electronic device, and 1C is a block diagram. [Figure 27] FIG. 1 is a diagram illustrating an example of an electronic device. [Figure 28] 1A, 1B, and 1C are diagrams illustrating an example of a vehicle. [Figure 29] FIG. 1 is a graph showing cycle characteristics of a secondary battery. [Figure 30] FIG. 10 is a diagram showing the continuous charge tolerance of a secondary battery. [Figure 31] FIG. 1 is a graph showing cycle characteristics of a secondary battery. [Figure 32] 1A and 1B are graphs showing cycle characteristics of a secondary battery. [Figure 33] FIG. 1 is a view showing an SEM photograph of a positive electrode active material according to one embodiment of the present invention. [Figure 34] 1A and 1B are graphs showing cycle characteristics of a secondary battery. [Figure 35] 1A and 1B are graphs showing cycle characteristics of a secondary battery. [Figure 36] FIG. 10 is a diagram showing cycle characteristics of a secondary battery (comparative example). [Figure 37] 1A to 1C illustrate an example of a method for manufacturing a positive electrode active material of one embodiment of the present invention. [Figure 38] FIG. 10 is a graph showing the cycle characteristics of the secondary battery of Example 4. [Figure 39] Graph of dQ / dV vs V for the sample of Example 4. [Figure 40] 1 shows an XRD pattern (low angle side) of the sample of Example 5. [Figure 41] 1 shows an XRD pattern (high angle side) of the sample of Example 5. [Figure 42] XRD patterns (low-angle side and high-angle side) of the sample of Example 5. [Figure 43] XRD patterns (low-angle side and high-angle side) of a sample of a comparative example. DETAILED DESCRIPTION OF THE INVENTION

[0059] 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 various modifications in form and details are possible by those skilled in the art. Furthermore, the present invention should not be construed as being limited to the description of the following embodiments. It is not something that can be done.

[0060] (Embodiment 1) An example of a method for manufacturing a positive electrode active material of one embodiment of the present invention will be described with reference to FIG.

[0061] <Step S11> First, as materials for the mixture 902, a halogen source such as a fluorine source or a chlorine source and magnesium Preferably, a lithium source is also provided.

[0062] As the fluorine source, for example, lithium fluoride, magnesium fluoride, etc. can be used. Among these, lithium fluoride has a relatively low melting point of 848°C, and the annealing process described below It is preferable because it is easily melted. Examples of the chlorine source include lithium chloride, magnesium chloride, etc. Examples of magnesium sources that can be used include magnesium fluoride and magnesium oxide. The lithium source may be cadmium, magnesium hydroxide, magnesium carbonate, etc. For example, lithium fluoride and lithium carbonate can be used as the catalyst. Lithium can be used as both a lithium source and a fluorine source. Sium can be used as both a fluorine source and a magnesium source.

[0063] In this embodiment, lithium fluoride LiF is prepared as a fluorine source and a lithium source, Magnesium fluoride (MgF2) will be prepared as a fluorine source and magnesium source. (Step S11 in Figure 1).

[0064] Lithium fluoride (LiF) and magnesium fluoride (MgF2) have a ratio of LiF:MgF2=65:35 When mixed at a molar ratio of about 100,000 to 100,000, the effect of lowering the melting point is maximized (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 (nearby) is more preferred.

[0065] If the subsequent mixing and grinding steps are to be carried out wet, a solvent is prepared. ketones such as acetone, alcohols such as ethanol and isopropanol, ethers, di- Xanthan Gum, acetonitrile, N-methyl-2-pyrrolidone (NMP), etc. can be used. It is more preferable to use an aprotic solvent that is less likely to react with lithium. In this embodiment, acetone is used (see step S11 in FIG. 1).

[0066] <Step S12> Next, the materials of the mixture 902 are mixed and crushed (step S12 in FIG. 1). This can be done by either dry or wet grinding, but the wet grinding method allows for smaller grinding. For mixing, a ball mill, a bead mill, or the like can be used. When using a zirconia ball as the media, it is preferable to use a zirconia ball as the media. Preferably, the mixing and grinding steps are carried out sufficiently to pulverize the mixture 902 into fine particles.

[0067] The mixing means is preferably a blender, a mixer, or a ball mill.

[0068] <Steps S13 and S14> The mixed and crushed materials are collected (step S13 in FIG. 1) to obtain a mixture 902 ( Step S14 in Figure 1).

[0069] 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 crystals described above will form in the charged state. It may be difficult to achieve the structure.

[0070] <Steps S15, S16, and S17> In addition, finely powdered nickel hydroxide (Ni(OH)2) is added for mixing in step S31. The finely powdered nickel hydroxide is prepared by mixing nickel hydroxide with acetone in advance. Step S15 and step S16 are performed to collect the powder. Nickel hydroxide is obtained (step S17).

[0071] <Steps S18, S19, and S20> Also, finely powdered aluminum hydroxide (Al(OH)3 ) to prepare the finely powdered aluminum hydroxide. Step S18 of mixing and step S19 of collecting are carried out. As a result, finely powdered aluminum hydroxide is obtained (step S20).

[0072] <Step S25> Also, a lithium source is prepared for mixing in step S31. A composite oxide containing lithium, a transition metal, and oxygen that has been synthesized in advance is used.

[0073] When using a pre-synthesized composite oxide containing lithium, transition metal, and oxygen In this specification, lithium, transition metals, and and a composite oxide containing lithium and oxygen, and a cathode active material containing lithium, cobalt, and Nickel, manganese, aluminum and oxygen are used, and elements other than the above main components are considered impurities. For example, when analyzed by glow discharge mass spectrometry, the total impurity concentration is 10,000p It is preferably 5000 ppm wt or less, and more preferably 5000 ppm wt or less. The total impurity concentration of transition metals such as titanium and arsenic is 3000 ppm wt or less. It is preferable that the content of the hydroxybenzoate is 1500 ppm by weight or less, and more preferable that the content of the hydroxybenzoate is 1500 ppm by weight or less.

[0074] For example, as a pre-synthesized lithium cobalt oxide, Lithium cobalt oxide particles (product name: Cellseed C-10N) can be used. The average particle size (D50) of the powder was approximately 12 μm, and the particle size was measured by glow discharge mass spectrometry (GD-MS). In the impurity analysis, the magnesium concentration and fluorine concentration were 50 ppm wt or less, and Calcium concentration, aluminum concentration and silicon concentration are 100 ppm wt or less, nickel concentration is 100 ppm wt or less The concentration of arsenic is 11 ppm or less, the concentration of sulfur is 500 ppm or less, and the concentration of arsenic is 11 ppm or less. 00 ppm wt or less, and the concentration of other elements other than lithium, cobalt and oxygen is 150 It is lithium cobalt oxide, which is less than ppm wt.

[0075] The composite oxide containing lithium, a transition metal, and oxygen in step S25 is formed by removing defects and strain. It is preferable that the crystal structure of the layered rock salt type has few impurities. It is preferable that the composite oxide contains lithium, a transition metal, and oxygen. If a large amount of impurities is included, there is a high possibility that the crystal structure will have many defects or strains.

[0076] <Step S31> Next, the mixture 902, a composite oxide having lithium, a transition metal, and oxygen, and a finely pulverized The aluminum hydroxide and the finely powdered nickel hydroxide are mixed (step S3 in FIG. 1). 1) The number of transition metal atoms in a composite oxide containing lithium, a transition metal, and oxygen, TM, The ratio of the number of magnesium atoms in the mixture 902 to that in MgMix1 is TM:MgMix1 =1:y (0.005≦y≦0.05), and TM:MgMix1=1 :y (0.007≦y≦0.04) is more preferable, and TM:MgMix1=1 A value of about 0.02 is even more preferable.

[0077] The mixing in step S31 is carried out after the mixing in step S12 in order not to destroy the particles of the composite oxide. For example, it is preferable to set the rotation speed to be milder than that of the mixing in step S12. It is preferable to use conditions with less heat or shorter time. For mixing, a ball mill, a bead mill, etc. can be used. When using a ball mill, for example, zirconia balls should be used as the media. is preferred.

[0078] The mixed materials are collected (step S32 in FIG. 1) to obtain a mixture 903 (step S32 in FIG. 1). Step S33).

[0079] Next, the mixture 903 is heated. This step is sometimes called annealing or firing.

[0080] The annealing is preferably carried out at a suitable temperature and time. The particle size and the size of the composite oxide having lithium, transition metal and oxygen in step S25 The temperature and composition of the particles vary depending on the conditions. Small particles require lower temperatures or Shorter times may be more preferable.

[0081] 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, 700° 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.

[0082] The temperature drop time after annealing is preferably, for example, 10 hours or more and 50 hours or less.

[0083] When the mixture 903 is annealed, the material with a low melting point (e.g., fluorine) in the mixture 903 is first melted. It is thought that the lithium ion (lithium chloride, melting point 848°C) melts and is distributed in the surface layer of the composite oxide particles. The presence of this molten material then lowers the melting point of other materials, causing them to melt. For example, magnesium fluoride (melting point 1263°C) melts and turns into a composite oxide. It is thought to be distributed in the surface layer of the particles.

[0084] The diffusion of elements contained in the mixture 903 is more pronounced in the surface and inner layers of the composite oxide particles than in the inner layers. Therefore, magnesium and halogens are more likely to dissolve in the surface layer and near the grain boundaries. As will be described later, the magnesium concentration in the surface layer and near the grain boundaries is higher than that in the interior. When the temperature is high, the change in the crystal structure can be more effectively suppressed.

[0085] The annealed material is collected (step S35 in FIG. 1). By the above steps, the positive electrode active material 100A-1 according to one embodiment of the present invention is produced. (Step S36 in FIG. 1).

[0086] (Embodiment 2) An example of a method for manufacturing a positive electrode active material of one embodiment of the present invention will be described with reference to FIGS.

[0087] This embodiment is the same as the first embodiment except for some differences, so the same parts will be simplified. Therefore, it will be omitted.

[0088] <Step S21> As shown in step S21 of FIG. 2, first, a fluorine source and chlorine are used as materials for a mixture 901. A halogen source, a magnesium source, a nickel source, and an aluminum source are prepared. A source of lithium is also preferably provided.

[0089] In this embodiment, lithium fluoride LiF is prepared as a fluorine source and a lithium source, Magnesium fluoride (MgF2) was prepared as a fluorine source and a magnesium source, and nickel was prepared as a nickel source. Nickel hydroxide is prepared as the aluminum source, and aluminum hydroxide is prepared as the aluminum source. (Step S21).

[0090] Also, a solvent is prepared for the subsequent wet mixing and grinding process. Acetone is used as the solvent. Use.

[0091] <Step S22> Next, the above materials are mixed and crushed (step S22 in FIG. 2). The mixing can be performed by dry or wet crushing. The wet method is preferable because it allows for finer pulverization. For example, a ball mill, a bead mill, etc. can be used. When a ball mill is used, For example, it is preferable to use zirconia balls as the media. It is preferable to carry out the above-mentioned step sufficiently to pulverize the material.

[0092] <Steps S23 and S24> The mixed and crushed materials are collected (step S23) to obtain a mixture 901 (step (P S24).

[0093] In step S25, a compound having lithium, a transition metal, and oxygen synthesized in advance is used. A composite oxide is used.

[0094] <Step S31> Next, the mixture 901 is mixed with a composite oxide containing lithium, a transition metal, and oxygen. (step S31).

[0095] The manufacturing procedure from step S31 onwards is the same as that of the first embodiment, so detailed description will be omitted. If the manufacturing procedure from step S31 onwards is followed, the positive electrode active material 10 0A-1 is obtained.

[0096] In this embodiment, steps S15 to S20 in the first embodiment are omitted. This can be done.

[0097] This embodiment mode can be freely combined with Embodiment Mode 1.

[0098] (Embodiment 3) An example of a method for manufacturing a positive electrode active material of one embodiment of the present invention will be described with reference to FIGS.

[0099] As shown in step S11 of FIG. 3, first, as a material for the mixture 902, a fluorine source, fluorine Lithium fluoride and magnesium fluoride, which is a magnesium source, are prepared. The melting point of aluminum is relatively low at 848°C, making it preferable because it melts easily during the annealing process described below. Lithium fluoride can be used as both a lithium source and a fluorine source. Magnesium chloride can be used as both a fluorine source and a magnesium source.

[0100] In this embodiment, lithium fluoride LiF is prepared as a fluorine source and a lithium source, Magnesium fluoride (MgF2) will be prepared as a fluorine source and magnesium source. (Step S11 in FIG. 3) The mole fraction of lithium fluoride LiF and magnesium fluoride MgF2 The ratio is preferably LiF:MgF2=x:1 (0≦x≦1.9), and LiF:M LiF:MgF2=x:1 (0.1≦x≦0.5) is more preferable, and LiF:MgF2=x:1 (x =0.33) is more preferable.

[0101] If the subsequent mixing and grinding steps are to be carried out wet, a solvent is prepared. ketones such as acetone, alcohols such as ethanol and isopropanol, ethers, di- Xanthan Gum, acetonitrile, N-methyl-2-pyrrolidone (NMP), etc. can be used. It is more preferable to use an aprotic solvent that is less likely to react with lithium. In this embodiment, acetone is used (see step S11 in FIG. 3).

[0102] Next, the materials of the mixture 902 are mixed and crushed (step S12 in FIG. 3). This can be done by either dry or wet grinding, but the wet grinding method allows for smaller grinding. For mixing, a ball mill, a bead mill, or the like can be used. When using a zirconia ball as the media, it is preferable to use a zirconia ball as the media. Preferably, the mixing and grinding steps are carried out sufficiently to pulverize the mixture 902 into fine particles.

[0103] The mixed and crushed materials are collected (step S13 in FIG. 3) to obtain a mixture 902 ( Step S14 in Figure 3).

[0104] 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 crystals described above will form in the charged state. It may be difficult to achieve the structure.

[0105] Next, a lithium source is prepared as shown in step S25. A composite oxide containing lithium, a transition metal, and oxygen that has been synthesized in advance is used.

[0106] For example, as a pre-synthesized lithium cobalt oxide, Lithium cobalt oxide particles (product name: Cellseed C-10N) can be used. The average particle size (D50) of the powder was approximately 12 μm, and the particle size was measured by glow discharge mass spectrometry (GD-MS). In the impurity analysis, the magnesium concentration and fluorine concentration were 50 ppm wt or less, and Calcium concentration, aluminum concentration and silicon concentration are 100 ppm wt or less, nickel concentration is 100 ppm wt or less The concentration of arsenic is 11 ppm or less, the concentration of sulfur is 500 ppm or less, and the concentration of arsenic is 11 ppm or less. 00 ppm wt or less, and the concentration of other elements other than lithium, cobalt and oxygen is 150 It is lithium cobalt oxide, which is less than ppm wt.

[0107] The composite oxide containing lithium, a transition metal, and oxygen in step S25 is formed by removing defects and strain. It is preferable that the crystal structure of the layered rock salt type has few impurities. It is preferable that the composite oxide contains lithium, a transition metal, and oxygen. If a large amount of impurities is included, there is a high possibility that the crystal structure will have many defects or strains.

[0108] Next, the mixture 902 is mixed with a composite oxide containing lithium, a transition metal, and oxygen. (Step S31 in FIG. 3) The number of transition metal atoms TM and the number of magnesium atoms MgMix1 in the mixture 902 The ratio is preferably TM:MgMix1=1:y (0.005≦y≦0.05). TM:MgMix1=1:y (0.007≦y≦0.04) is more preferable. TM:MgMix1=1:0.02 is more preferable.

[0109] The mixing in step S31 is carried out after the mixing in step S12 in order not to destroy the particles of the composite oxide. For example, it is preferable to set the rotation speed to be milder than that of the mixing in step S12. It is preferable to use conditions with less heat or shorter time. For mixing, a ball mill, a bead mill, etc. can be used. When using a ball mill, for example, zirconia balls should be used as the media. is preferred.

[0110] The mixed materials are collected (step S32 in FIG. 3) to obtain a mixture 903 (step S32 in FIG. 3). Step S33).

[0111] Next, the mixture 903 is heated (step S34 in FIG. 3).

[0112] The annealing is preferably carried out at a suitable temperature and time. The particle size and the size of the composite oxide having lithium, transition metal and oxygen in step S25 The temperature and composition of the particles vary depending on the conditions. Small particles require lower temperatures or Shorter times may be more preferable.

[0113] 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.

[0114] 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.

[0115] The temperature drop time after annealing is preferably, for example, 10 hours or more and 50 hours or less.

[0116] When the mixture 903 is annealed, the material with a low melting point (e.g., fluorine) in the mixture 903 is first melted. It is thought that the lithium ion (lithium chloride, melting point 848°C) melts and is distributed in the surface layer of the composite oxide particles. The presence of this molten material then lowers the melting point of other materials, causing them to melt. For example, magnesium fluoride (melting point 1263°C) melts and turns into a composite oxide. It is thought to be distributed in the surface layer of the particles.

[0117] The diffusion of elements contained in the mixture 903 is more pronounced in the surface and inner layers of the composite oxide particles than in the inner layers. Therefore, magnesium and halogens are more likely to dissolve in the surface layer and near the grain boundaries. As will be described later, the magnesium concentration in the surface layer and near the grain boundaries is higher than that in the interior. When the temperature is high, the change in the crystal structure can be more effectively suppressed.

[0118] The annealed material is collected (step S35 in FIG. 3) to obtain a mixture 904 (FIG. 3, step S36).

[0119] Next, as shown in step S50, the mixture 904 is mixed with finely powdered nickel hydroxide. Then, the mixed material is collected (step S51). Step S15 of mixing nickel hydroxide and acetone and step S16 of recovering the mixture are performed in advance. In step S16, finely powdered nickel hydroxide is obtained (step S17).

[0120] The materials mixed in step S50 are collected in step S51 to obtain a mixture 905 (see FIG. 3). Step S52).

[0121] Next, steps S53 to S55 are carried out to obtain the positive electrode active material of one embodiment of the present invention. Metal Z is added by, for example, a liquid phase method such as a sol-gel method, a solid phase method, or the like. method, sputtering method, evaporation method, CVD (chemical vapor deposition) method, PLD (pulsed laser deposition) method Methods such as the filtration method can be applied.

[0122] As shown in FIG. 3, first, in step S52, a metal source is prepared. When the sol-gel method is applied, a solvent for the sol-gel method is prepared. The metal Z may be aluminum, a metal oxide, a metal hydroxide, a metal oxide, or the like. In this case, for example, the number of cobalt atoms in lithium cobalt oxide is 1, and the metal source is The amount of aluminum that is used should be between 0.001 and 0.02 times the amount of nickel. 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 content of nickel in the alloy should be 0.001 times or more and 0.02 times or less. In the case of nickel, for example, the number of cobalt atoms in lithium cobalt oxide is 1, The aluminum content of the metal source is 0.001 times or more and 0.02 times or less, and the aluminum content of the metal source is The nickel content should be between 0.001 and 0.02 times.

[0123] As an example, a sol-gel method is used, and aluminum isopropoxide is used as a metal source. An example in which isopropanol is used as a solvent will be shown (step S52 in FIG. 3).

[0124] Next, aluminum alkoxide is dissolved in alcohol, and then lithium cobalt oxide is added. The particles are mixed (step S53 in FIG. 3).

[0125] The amount of metal alkoxide required varies depending on the particle size of the lithium cobalt oxide. When aluminum isopropoxide is used, the particle size (D50) of lithium cobalt oxide is 20 If the number of cobalt atoms in lithium cobalt oxide is 1, then the number of cobalt atoms in aluminum is 1. The aluminum content of the isopropoxide is adjusted to 0.001 to 0.02 times. It is preferable to do so.

[0126] Next, the mixture of the alcohol solution of metal alkoxide and the lithium cobalt oxide particles was added to water. Stirring is performed in a steam-containing atmosphere. Stirring can be performed, for example, with a magnetic stirrer. The stirring time is determined based on the time it takes for the water in the atmosphere and the metal alkoxide to undergo hydrolysis and polycondensation reactions. For example, 4 hours, 25°C, 90% RH (relative humidity). It can be done under conditions of humidity (relative humidity). and in an atmosphere that is not temperature controlled, such as the atmospheric atmosphere in a draft chamber. In such a case, it is preferable to carry out the stirring for a longer period of time. For example, it may be left at room temperature for 12 hours or more.

[0127] By reacting water vapor in the atmosphere with metal alkoxide, the reaction is more efficient than when liquid water is added. The sol-gel reaction can be carried out slowly even at room temperature. This reaction allows for a higher yield than, for example, heating at a temperature above the boiling point of the alcohol solvent. The sol-gel reaction can be carried out slowly. By carrying out the sol-gel reaction slowly, This allows the formation of a high-quality coating layer with a uniform thickness.

[0128] After the above treatment, the precipitate is collected from the mixed solution (step S54 in FIG. 3). The method of filtration, centrifugation, evaporation to dryness, etc. can be applied. It can be washed with the same alcohol as the solvent used to dissolve the oxide. When using a solvent, separation of the solvent and the precipitate is not necessary in this step. For example, the precipitate may be collected in the drying step of the next step (step S54).

[0129] Next, the collected residue is dried to obtain a mixture 904 (Step S54 in FIG. 3). The drying process may be, for example, vacuum or forced air drying at 80° C. for 1 hour to 4 hours.

[0130] Next, the resulting mixture is heated (step S55 in FIG. 3).

[0131] The heating time is preferably 1 hour or more and 80 hours or less within the heating temperature range. Desirable.

[0132] The heating temperature is preferably less than 1000°C, more preferably 700°C or higher and 950°C or lower. , and more preferably about 850°C.

[0133] The heating is preferably carried out in an atmosphere containing oxygen.

[0134] In this embodiment, the heating temperature is set to 850° C. and maintained for 2 hours. °C / h, and the oxygen flow rate is 10 L / min.

[0135] The heating temperature in step S55 is lower than the heating temperature in step S34. preferable.

[0136] <Steps S56 and S57> Next, the cooled particles are collected (step S56 in FIG. 3). By the above steps, a positive electrode active material 100A-2 according to one embodiment of the present invention is prepared. This can be done (step S57 in FIG. 3).

[0137] The positive electrode active material 100A-2 obtained by the above-mentioned manufacturing method will be described. 00A-2 under a scanning electron microscope. A photograph taken using a scanning electron microscope (SEM) is shown in Figure 33.

[0138] [Positive electrode active material structure] Materials with a layered rock-salt crystal structure, such as lithium cobalt oxide (LiCoO2), are It has a high capacitance and is known to be an excellent positive electrode active material for secondary batteries. An example of a material with a crystalline structure is a composite oxide represented by LiMO2. An example of M is one or more selected from Co and Ni. In addition to one or more selected from Co and Ni, one or more selected from Al and Mn Examples include:

[0139] The Jahn-Teller effect in transition metal compounds depends on the number of electrons in the d orbital of the transition metal: The strength of the effect is known to vary.

[0140] In compounds containing nickel, distortion is likely to occur due to the Jahn-Teller effect. Therefore, when LiNiO2 is charged and discharged at high voltage, In LiCoO2, the Jahn-Teller effect is This suggests that the effect of the ion implantation is small, and the resistance to charging and discharging at high voltages may be superior, which is preferable. It's nice.

[0141] The positive electrode active material will be described with reference to Figs. 4 and 5. The case where cobalt is used as the transition metal in the substance will be described.

[0142] <Cathode active material> In the positive electrode active material of one embodiment of the present invention, the CoO2 layer is displaced during repeated high-voltage charge and discharge. Furthermore, the change in volume can be reduced. The positive electrode active material of one embodiment of the present invention can achieve excellent cycle characteristics. The positive electrode active material according to one embodiment of the present invention can have a stable crystal structure in a charged state at a high voltage. Therefore, the positive electrode active material of one embodiment of the present invention has a short circuit resistance when maintained in a charged state at a high voltage. In such cases, safety is improved, making it preferable. .

[0143] 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.

[0144] The crystal structure of the positive electrode active material 100A-1 before and after charge and discharge is shown in FIG. -1 is a composite oxide containing lithium, cobalt, and oxygen. It is preferable that the metal contains nesium. It is also preferable that the metal contains a halogen such as fluorine or chlorine. It is also preferable to include aluminum and nickel.

[0145] The crystal structure at charge depth 0 (discharged state) in Figure 5 is the same as that in Figure 4, R-3m(O3). On the other hand, the positive electrode active material 100A-1 and the mixture 904 are fully charged at a charge depth of H1 The crystal has a structure different from the R-3 type crystal structure. Although it is not a crystalline structure, ions such as cobalt and magnesium occupy the 6-coordinated oxygen sites. The arrangement of cations has a symmetry similar to that of the spinel type. In this case, it is called a pseudo-spinel crystal structure. The pseudo-spinel crystal structure shown in Figure 5 In the diagram, the lithium Although the display of cobalt is omitted, in reality, the amount of cobalt between the CoO2 layers is, for example, 20 atomic % or more. The lithium below is present. In addition, both the O3 type crystal structure and the pseudospinel type crystal structure In this case, magnesium is present in a dilute form between the CoO2 layers, i.e., at the lithium sites. It is also preferable that halogens such as fluorine are present randomly and dilutely at the oxygen sites. It is preferable that

[0146] In addition, in the pseudospinel crystal structure, light elements such as lithium occupy the four oxygen coordination positions. In this case, the ion arrangement also has a symmetry similar to that of the spinel type.

[0147] 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.

[0148] 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.

[0149] In the case of the positive electrode active material 100A-1 and the mixture 904, a large amount of lithium was released when the battery was charged at a high voltage. When the positive electrode active material 100C is used, the change in the crystal structure is suppressed more than in the positive electrode active material 100C of the comparative example. For example, as shown by the dotted line in Figure 5, there is almost no misalignment of the CoO2 layers in these crystal structures. .

[0150] More specifically, the positive electrode active material 100A-1 and the mixture 904 are For example, the comparative positive electrode active material 100C has a H1-3 type The charging voltage at which the crystal structure is formed is, for example, about 4.6V based on the potential of lithium metal. There is a charging voltage range where the crystal structure of R-3m(O3) can be maintained even at high charging voltages. High voltage region, for example, 4.65V to 4.7V based on the potential of lithium metal Even at a voltage of 0.1 V, there is a region where the pseudo-spinel crystal structure can be formed. When the temperature is increased, H1-3 type crystals can be observed. For example, when graphite is used as the negative electrode active material, the voltage of the secondary battery must be 4.3V or higher. There is a charging voltage range where the crystal structure of R-3m(O3) can be maintained even below 5V. Furthermore, in the region where the charging voltage is increased, for example, the potential of lithium metal is 4.35V or more. Even below 0.55V, there exists a region in which a pseudospinel crystal structure can be formed.

[0151] Therefore, in the positive electrode active material 100A-1 and the mixture 904, the charge and discharge were repeated at a high voltage. The crystal structure is not easily broken even when turned over.

[0152] The pseudospinel crystal structure has the coordinates of cobalt and oxygen in the unit cell as follows: Co (0,0,0.5), O(0,0,x), 0.20≦x≦0.25 can.

[0153] Magnesium exists randomly and dilutely between the CoO2 layers, i.e., at the lithium sites. This has the effect of suppressing the displacement of the CoO2 layers. Therefore, magnesium is a positive electrode active material 100% It is preferable that magnesium is distributed throughout the particles of A-1 and mixture 904. In order to distribute the positive electrode active material 100A-1 and the mixture 904 in the process of preparing the positive electrode active material 100A-1 and the mixture 904, It is preferable to carry out a heat treatment.

[0154] However, if the heat treatment temperature is too high, cation mixing occurs and magnesium When magnesium is present in the cobalt site, If the temperature of the heat treatment is too high, the effect of maintaining the structure of R-3m will be lost. However, there are concerns about adverse effects such as cobalt being reduced to a divalent state and lithium evaporating. can be.

[0155] Therefore, before the heat treatment to distribute magnesium throughout the particles, cobalt oxide It is preferable to add a halogen compound such as a fluorine compound to lithium. Adding substances to lithium cobalt oxide lowers its melting point. At a temperature where on-mixing is unlikely to occur, it is easy to distribute magnesium throughout the particles. Furthermore, if a fluorine compound is present, the electrolyte will have corrosion resistance to the hydrofluoric acid produced by decomposition. can be expected to improve.

[0156] If the magnesium concentration is increased above a desired value, the effect on stabilizing the crystal structure is reduced. In addition to the lithium site, magnesium may also be present at the cobalt site. This is thought to be because the magnesium contained in the positive electrode active material of one embodiment of the present invention also enters the matrix. The number of um atoms is preferably 0.001 times or more and 0.1 times or less the number of cobalt atoms, and more preferably 0.0 More preferably, it is greater than 1 and less than 0.04, and even more preferably about 0.02. The magnesium concentration shown in is determined by, for example, measuring the magnesium content of the entire particle of the positive electrode active material using ICP-MS or the like. It may be a value obtained by elementary analysis, or a value obtained by mixing raw materials in the process of producing the positive electrode active material. It may be based on.

[0157] Lithium cobalt oxide is added with metals other than cobalt (hereinafter referred to as metal Z), such as nickel, One or more metals selected from aluminum, manganese, titanium, vanadium and chromium They may be added, and it is particularly preferred to add one or more of nickel and aluminum. Manganese, titanium, vanadium, and chromium may easily take on a stable tetravalent state. The addition of the metal Z may contribute significantly to the stability of the positive electrode active material of one embodiment of the present invention. For example, in some materials, the crystalline structure may become more stable when charged at a high voltage. In the positive electrode active material 100A-1 according to one embodiment of the present invention, the metal Z is lithium cobalt oxide. It is preferable to add it at a concentration that does not significantly change the crystallinity of the polymer. It is preferable that the amount is such that the Jahn-Teller effect is not exhibited. This refers to a metal that is added to lithium cobalt oxide during the manufacturing process.

[0158] As the magnesium concentration of the positive electrode active material 100A-1 according to one embodiment of the present invention increases, the positive electrode active material 100A-1 The capacity of the electrode active material may decrease. For example, the lithium site may contain magnesium. It is possible that the inclusion of sodium reduces the amount of lithium that contributes to charging and discharging. In addition, excess magnesium may produce magnesium compounds that do not contribute to charging and discharging. The positive electrode active material of one embodiment of the present invention contains nickel as the metal Z in addition to magnesium. By doing so, it may be possible to increase the capacity per weight and per volume. Furthermore, the positive electrode active material of one embodiment of the present invention may contain aluminum as the metal Z in addition to magnesium. Having a high capacity per weight and volume may be possible Furthermore, the positive electrode active material of one embodiment of the present invention may contain nickel and aluminum in addition to magnesium. By having a high density, it may be possible to increase the capacity per weight and volume. do.

[0159] The concentrations of elements such as magnesium and metal Z contained in the positive electrode active material of one embodiment of the present invention are as follows: is expressed using the number of atoms.

[0160] The number of nickel atoms in the positive electrode active material 100A-1 of one embodiment of the present invention is 7.5% or less of the number of children is preferable, 0.05% to 4% is preferable, 0.1% to 2% The nickel concentration shown here is preferably as follows: The value may be obtained by elemental analysis of the entire particles of the active material, or may be obtained during the process of producing the positive electrode active material. The value may be based on the blend of ingredients in the

[0161] The number of aluminum atoms in the positive electrode active material 100A-1 of one embodiment of the present invention is The content of the atoms is preferably 0.05% or more and 4% or less, more preferably 0.1% or more and 2% or less of the total number of atoms. The aluminum concentration shown here is determined by measuring the aluminum concentration of the entire particles of the positive electrode active material using, for example, ICP-MS. The value may be a value obtained by elemental analysis of the positive electrode active material, or a value obtained by blending raw materials in the process of producing the positive electrode active material. It may be based on value.

[0162] If the electrolyte contains LiPF6, hydrogen fluoride may be generated due to hydrolysis. In addition, hydrogen fluoride is produced by the reaction of PVDF, which is used as a component of the positive electrode, with alkali. The decrease in hydrogen fluoride concentration in the electrolyte may cause corrosion of the current collector. In addition, it may be possible to prevent the adhesion of PVDF from gelling or becoming insoluble. It may be possible to suppress the decline.

[0163] <Particle size> If the particle size of the positive electrode active material 100A-1 and the mixture 904 is too large, it becomes difficult for lithium to diffuse. When the active material layer is applied to the current collector, the surface of the active material layer becomes too rough. If the particle size is too small, it becomes difficult to support the active material layer when it is applied to the current collector, and the reaction with the electrolyte may be excessive. Therefore, the average particle size (D50: also called the median diameter) ) is preferably 1 μm or more and 100 μm or less, and more preferably 2 μm or more and 40 μm or less. It is preferable that the thickness is 5 μm or more and 30 μm or less, more preferable.

[0164] <Analysis method> According to one aspect of the present invention, a positive electrode active material exhibits a pseudospinel crystal structure when charged at a high voltage. The positive electrode active material 100A-1 of the embodiment, whether or not the mixture 904 is used, is determined by the positive electrode charged at a high voltage. XRD, electron diffraction, neutron diffraction, electron spin resonance (ESR), nuclear magnetic resonance (NM XRD can be used to analyze the cobalt in the positive electrode active material. The symmetry of transition metals such as ZnO can be analyzed with high resolution, and the degree of crystallinity and crystal orientation can be compared. It is possible to analyze the periodic distortion of the lattice and the crystallite size. This is preferable in that sufficient accuracy can be obtained even when the positive electrode is measured as it is.

[0165] As described above, the positive electrode active material 100A-1 and the mixture 904 according to one embodiment of the present invention have high It is characterized by the fact that there is little change in the crystal structure between the charged and discharged states. Materials with a crystal structure that changes significantly between the charged and discharged states and that accounts for 50 wt% or more of the material are: It is not desirable because it cannot withstand high voltage charging and discharging. It is important to note that the desired crystal structure may not be achieved. Although they have in common the fact that they are lithium cobalt oxides containing fluorine and fluorine, when they are charged at high voltages, In the case of the pseudo-spinel type crystal structure being 60 wt% or more, and the H1-3 type crystal structure being 50 wt% or more, In addition, at a certain voltage, a pseudo-spinel crystal structure is formed. It becomes nearly 100 wt%, and when the voltage is further increased, the H1-3 type crystal structure is generated. Therefore, the positive electrode active material 100A-1 according to one embodiment of the present invention and the mixture 904 To determine whether or not this is the case, analysis of the crystal structure, including XRD, is required.

[0166] However, when the positive electrode active material is in a high-voltage charged or discharged state, its crystalline structure changes when it comes into contact with the air. For example, the crystal structure may change from a pseudo-spinel type to an H1-3 type. Therefore, all samples were stored in an inert atmosphere such as argon. It is preferable to use a bonding method.

[0167] <Comparative Example Positive Electrode Active Material 100C> The comparative positive electrode active material 100C shown in FIG. 5 was prepared by the method described later. The cobalt oxide shown in Figure 5 is lithium cobalt oxide (LiCoO2) with no added nesium. As described in Non-Patent Documents 1 and 2, lithium nitrate has a charge depth of The crystal structure changes depending on the

[0168] As shown in Figure 5, lithium cobalt oxide at a charge depth of 0 (discharged state) is in the space group R- It has a region with a 3m crystal structure, and there are three CoO2 layers in the unit cell. Therefore, this crystal structure is sometimes called an O3 type crystal structure. The term "octahedral structure" refers to a structure in which six oxygen atoms are coordinated to form a single octahedron, which is connected to the plane by edge-sharing. .

[0169] At a charge depth of 1, the crystal structure has the space group P-3m1, and there is Co in the unit cell. There is one O2 layer, so this crystal structure is sometimes called an O1-type crystal structure.

[0170] In addition, when the charge depth is about 0.88, lithium cobalt oxide has a crystal structure of the space group R-3m. This structure is similar to the structure of CoO2, such as P-3m1(O1), and R-3m(O 3) and the structure of LiCoO2, and the structure of The crystal structure is sometimes called the H1-3 type crystal structure. has twice the number of cobalt atoms per unit cell as the other structures. In this specification, the c-axis of the H1-3 type crystal structure is used as a unit to facilitate comparison with other structures. This will be shown in a diagram of half the size of a knit cell.

[0171] As an example, the H1-3 type crystal structure has a unit cell as described in Non-Patent Document 3. The coordinates of cobalt and oxygen in 1(0, 0, 0.27671±0.00045), O2(0, 0, 0.11535±0. 00045), where O1 and O2 are oxygen atoms. The H1-3 crystal structure is formed by a unit cell with one cobalt and two oxygen atoms. On the other hand, as will be described later, the pseudospinel crystal structure of one embodiment of the present invention is preferably is represented by a unit cell with one cobalt and one oxygen. The symmetry between cobalt and oxygen is different between the spinel structure and the H1-3 structure. The pseudospinel structure is less different from the O3 structure than the H1-3 type structure. It is more preferable to use any one of the unit cells to represent the crystal structure of the positive electrode active material. For example, in the Rietveld analysis of XRD, the selection of GOF (Goodness of Field) s of fit) should be selected to be smaller.

[0172] High-voltage charging where the charging voltage is 4.6V or higher based on the oxidation-reduction potential of lithium metal When the battery is repeatedly charged or discharged to a deep depth of charge of 0.8 or more, Lithium cobalt oxide has a H1-3 type crystal structure and a R-3m(O3) structure in the discharged state. The crystal structure changes (i.e., non-equilibrium phase changes) between these two states.

[0173] However, these two crystal structures have a large misalignment of the CoO2 layers. As shown by the arrows and the lines, in the H1-3 type crystal structure, the CoO2 layer is larger than the R-3m(O3) layer. Such dynamic structural changes have a negative effect on the stability of the crystal structure. Yes.

[0174] Furthermore, the difference in volume is large. When comparing the same number of cobalt atoms, the H1-3 type crystal The difference in volume between the structure and the O3-type crystal structure in the discharged state is more than 3.0%.

[0175] In addition, the H1-3 type crystal structure has continuous CoO2 layers such as P-3m1(O1). The resulting structure is likely to be unstable.

[0176] Therefore, repeated high-voltage charging and discharging causes the crystal structure of lithium cobalt oxide to collapse. The breakdown of the crystal structure causes a deterioration in cycle characteristics. , the number of sites where lithium can exist stably decreases, and lithium insertion and desorption becomes difficult. This is thought to be the reason.

[0177] (Fourth embodiment) In this embodiment, the positive electrode active material 100A-1 and the mixture 904 described in the previous embodiment are Examples of materials that can be used in secondary batteries having the above structure will be described.

[0178] <Configuration example 1 of secondary battery> The following description will be given taking as an example a secondary battery in which a positive electrode, a negative electrode, and an electrolyte are enclosed in an exterior body. do.

[0179] [Positive electrode] The positive electrode has a positive electrode active material layer and a positive electrode current collector.

[0180] <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.

[0181] As the positive electrode active material, the positive electrode active materials 100A-1 and 100A-2 described in the previous embodiment are used. The positive electrode active materials 100A-1 and 100A-2 described in the previous embodiments can be used. By using -2, a secondary battery with high capacity and excellent cycle characteristics can be obtained.

[0182] 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.

[0183] 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.

[0184] 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.

[0185] A graphene compound may also be used as the conductive additive.

[0186] 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).

[0187] 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.

[0188] In the following, as an example, a graphene compound is used as a conductive additive in the active material layer 200. An example of the cross-sectional configuration in this case will be described.

[0189] 6(A) shows a vertical cross-sectional view of the active material layer 200. The active material layer 200 is made of granular positive electrode active material. The conductive material 100, the graphene compound 201 as a conductive additive, and a binder (not shown) are Here, the graphene compound 201 may be, for example, graphene or multi-graphene. Here, the graphene compound 201 preferably has a sheet shape. In addition, the graphene compound 201 may be a multi-graphene or (and) a composite. A number of graphenes may be partially overlapped to form a sheet.

[0190] In the vertical cross section of the active material layer 200, as shown in FIG. 6(B), In FIG. 6(B), the sheet-like graphene compound 201 is dispersed almost uniformly. The graphene compound 201 is shown in bold in the figure, but in reality it is a single layer of carbon molecules or The graphene compounds 201 are thin films having a thickness of multiple layers. The positive electrode active material 100 is partially covered with the material 100 or is attached to the surface of a plurality of particles of the positive electrode active material 100. Since they are formed so as to be parallel to each other, they are in surface contact with each other.

[0191] 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.

[0192] Here, graphene oxide is used as the graphene compound 201, and is mixed with an active material to form an active material. After forming the layer that will become the graphene compound layer 200, it is preferable to reduce the layer. By using graphene oxide, which has extremely high dispersibility in polar solvents, The compound 201 can be dispersed approximately uniformly inside the active material layer 200. The solvent is evaporated from the dispersion medium containing the graphene oxide dispersed in the solution, and the graphene oxide is reduced. Therefore, the graphene compound 201 remaining in the active material layer 200 partially overlaps with each other. By dispersing the particles so that they come into surface contact with each other, a three-dimensional conductive path can be formed. The reduction of graphene oxide may be carried out by, for example, heat treatment or by using a reducing agent. You may go.

[0193] Therefore, unlike granular conductive additives such as acetylene black, which come into point contact with the active material, Since the phenyl compound 201 enables surface contact with low contact resistance, it is not necessary to use a conventional conductive additive. The electrical conductivity between the granular positive electrode active material 100 and the graphene compound 201 can be improved with a smaller amount than that of the graphene compound 201. Therefore, the ratio of the positive electrode active material 100 in the active material layer 200 can be increased. This makes it possible to increase the discharge capacity of the secondary battery.

[0194] 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.

[0195] 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.

[0196] 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

[0197] 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.

[0198] The binder may be used in combination with two or more of the above.

[0199] 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.

[0200] 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.

[0201] 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.

[0202] 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

[0203] <Positive electrode current collector> The positive electrode current collector may be made of metals such as stainless steel, gold, platinum, aluminum, titanium, etc. Highly conductive materials such as these alloys can be used. It is preferable that silicon, titanium, neodymium, scavenger, etc. are not eluted at the potential of the positive electrode. Aluminum alloys containing elements such as indium and molybdenum that improve heat resistance are used. It can also be formed from a metal element that reacts with silicon to form silicide. Metal elements that react with silicon to form silicide include zirconium, titanium, and Tantalum, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten , cobalt, nickel, etc. Current collectors are available in foil, plate (sheet), mesh, and punched shapes. The current collector may be in the form of a metal, an expanded metal, or the like. It is recommended to use a thickness of 5 μm or more and 30 μm or less.

[0204] [Negative electrode] The negative electrode has a negative electrode active material layer and a negative electrode current collector. and a binder.

[0205] <Negative electrode active material> As the negative electrode active material, for example, an alloy-based material or a carbon-based material can be used.

[0206] 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.

[0207] 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.

[0208] Carbon materials include graphite, easily graphitizable carbon (soft carbon), and non-graphitizable carbon (hard carbon). carbon nanotubes, graphene, carbon black, etc. stomach.

[0209] 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.

[0210] 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.

[0211] 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.

[0212] 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 / cm3 )of This is preferable.

[0213] 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.

[0214] 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.

[0215] 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.

[0216] <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.

[0217] [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:

[0218] 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.

[0219] 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.

[0220] 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.

[0221] 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%.

[0222] Alternatively, a polymer gel electrolyte may be used in which a polymer is swollen with an electrolytic solution.

[0223] The use of polymer gel electrolyte increases safety against leakage etc. The pond can be made thinner and lighter.

[0224] 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.

[0225] 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.

[0226] 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.

[0227] [Separator] The secondary battery preferably has a separator. Examples of the separator include: Paper, nonwoven fabric, glass fiber, ceramics, or nylon (polyamide), vinylon (polyamide) vinyl alcohol fiber), polyester, acrylic, polyolefin, polyurethane The separator can be made of synthetic fibers or the like. It is preferable to process the electrode into a shape and place it so as to wrap either the positive electrode or the negative electrode.

[0228] 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.

[0229] 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.

[0230] 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. .

[0231] 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,

[0232] [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.

[0233] <Configuration example 2 of secondary battery> As an example of the configuration of a secondary battery, the configuration of a secondary battery using a solid electrolyte layer will be described below. Reveal.

[0234] As shown in FIG. 7A, a secondary battery 400 of one embodiment of the present invention includes a positive electrode 410, a solid electrolyte layer 420 and a negative electrode 430 .

[0235] The positive electrode 410 includes a positive electrode current collector 413 and a positive electrode active material layer 414. The positive electrode active material layer 414 has a positive electrode active material 411 and a solid electrolyte 421. It may also contain auxiliaries and binders.

[0236] The solid electrolyte layer 420 includes a solid electrolyte 421. The solid electrolyte layer 420 is connected to the positive electrode 410. The negative electrode 430 is located between the positive electrode active material 411 and the negative electrode active material 431. It is an area.

[0237] The negative electrode 430 includes a negative electrode current collector 433 and a negative electrode active material layer 434. The negative electrode active material layer 434 has a negative electrode active material 431 and a solid electrolyte 421. The negative electrode 430 may contain an auxiliary agent and a binder. 7B, the negative electrode 430 may be a negative electrode 430 that does not have a solid electrolyte 421. When metallic lithium is used for the negative electrode 430, the energy density of the secondary battery 400 can be improved. This is preferable.

[0238] As shown in FIG. 8(A), a combination of a positive electrode 410, a solid electrolyte layer 420, and a negative electrode 430 A secondary battery may be formed by stacking a plurality of cathodes 410, solid electrolyte layers 420, and By stacking the negative electrode 430 and the negative electrode 430, the voltage of the secondary battery can be increased. , when a combination of a positive electrode 410, a solid electrolyte layer 420, and a negative electrode 430 is stacked in four layers, FIG.

[0239] The secondary battery 400 of one embodiment of the present invention may be a thin-film all-solid-state battery. The battery is manufactured by gas phase methods (vacuum deposition, pulsed laser deposition, aerosol deposition, spa It can be produced by depositing the positive electrode, solid electrolyte, negative electrode, wiring electrode, etc. using the deposition method. For example, as shown in FIG. 8B, a wiring electrode 441 and a wiring electrode 442 are provided on a substrate 440. After forming the wiring electrode 441, the positive electrode 410 is formed on the wiring electrode 441, and the solid electrolyte layer 42 is formed on the positive electrode 410. 0 is formed, and a negative electrode 430 is formed on the solid electrolyte layer 420 and the wiring electrode 442 to form a secondary battery. The pond 400 can be produced. The substrate 440 can be a ceramic substrate or a glass substrate. , a plastic substrate, a metal substrate, or the like can be used.

[0240] The solid electrolyte 421 of the solid electrolyte layer 420 may be, for example, a sulfide-based solid electrolyte, an acid A carbide-based solid electrolyte, a halide-based solid electrolyte, or the like can be used.

[0241] Sulfide-based solid electrolytes include thiosilicon-based (Li 10 GeP2S 12 , Li 3.25 Ge 0.25 P 0.75 S4, etc.), sulfide glass (70Li2S・30P2S5, 30Li2 S·26B2S3·44LiI, 63Li2S·38SiS2·1Li3PO4, 57L i2S・38SiS2・5Li4SiO4, 50Li2S・50GeS2, etc.), sulfide crystals Crystallized glass (Li7P3S 11 , Li 3.25 P 0.95 S4, etc.) are included. Solid electrolytes have high conductivity, can be synthesized at low temperatures, and are relatively soft. This has the advantage that the conductive path is easily maintained even after charging and discharging.

[0242] Oxide-based solid electrolytes include materials with a perovskite crystal structure (La 2 / 3-x Li 3x TiO3, etc.), materials with NASICON-type crystal structure (Li 1+x Al x Ti 2- x (PO4)3, etc.), materials with garnet-type crystal structure (Li7La3Zr2O 12 etc. ) Materials having a LISICON-type crystal structure (Li 14 ZnGe4O 16 etc.), LLZO (Li7La3Zr2O 12 ), oxide glasses (Li3PO4-Li4SiO4, 50L i4SiO4·50Li3BO3 etc.), oxide crystallized glasses (Li 1.07 Al 0.69 Ti 1.46 (PO4)3, Li 1.5 Al 0.5 Ge 1.5 (PO4)3 etc.) are included . Oxide-based solid electrolytes have the advantage of being stable in the atmosphere.

[0243] Halide-based solid electrolytes include LiAlCl4, Li3InBr6, LiF, LiCl , LiBr, LiI, etc. Also, composite materials in which these halide-based solid electrolytes are filled in the pores of porous aluminum oxide or porous silica can also be used as solid electrolytes .

[0244] Also, different solid electrolytes may be mixed and used.

[0245] Among them, Li 1+x Al x Ti 2-x (PO4)3( 0<x<1) (hereinafter, LATP) contains aluminum and titanium, which are elements that the positive electrode active material used in the secondary battery 400 of one aspect of the present invention may have. Therefore, a synergistic effect can be expected for improving the cycle characteristics, which is preferable. Also, an improvement in productivity due to reduction of processes can be expected . In the present specification etc., the NASICON-type crystal structure is a compound represented by M2(XO4)3 (M: transition metal, X: S, P, As, Mo, W, etc.), and MO6 octahedra and XO . . metal, X: S, P, As, Mo, W, etc.), and is a compound represented by MO6 octahedra and XO It refers to a structure in which four tetrahedrons are arranged three-dimensionally with their vertices shared.

[0246] [Shape of exterior body and secondary battery] The exterior body of the secondary battery 400 according to one embodiment of the present invention can be made of various materials and in various shapes. However, it is preferable that the positive electrode, the solid electrolyte layer, and the negative electrode have a function of applying pressure thereto.

[0247] For example, Figure 9 shows an example of a cell for evaluating materials for all-solid-state batteries.

[0248] FIG. 9(A) is a cross-sectional view of the test cell. The test cell is made up of a lower member 761 and an upper member 762. 62 and a fixing screw and a wing nut 764 for fixing them. By rotating the electrode plate 753, the evaluation material is fixed in place. An insulator 766 is provided between the lower member 761 and the upper member 762. An O-ring 76 is provided between the upper member 762 and the holding screw 763 for sealing. 5 is provided.

[0249] The material to be evaluated is placed on an electrode plate 751, surrounded by an insulating tube 752, and an electric It is pressed by the electrode plate 753. The figure is shown in Figure 9(B).

[0250] As an example of the evaluation material, a laminate of a positive electrode 750a, a solid electrolyte layer 750b, and a negative electrode 750c is shown. The cross-sectional view is shown in Figure 9(C). Note that the same The same symbols are used for the locations.

[0251] The electrode plate 751 and the lower member 761 electrically connected to the positive electrode 750a are It can be said that the electrode plate electrically connected to the negative electrode 750c corresponds to a terminal. The electrode plate 753 and the upper member 762 can be said to correspond to the negative terminal. The electrical resistance etc. is measured by applying pressure to the evaluation material through the electrode plate 751 and the electrode plate 753. can be measured.

[0252] In addition, a package with excellent airtightness may be used for the exterior body of the secondary battery according to one embodiment of the present invention. For example, a ceramic package or a resin package can be used. In addition, when sealing the exterior body, it is necessary to shut out the outside air and seal it in a sealed atmosphere, for example, in a glove box. It is preferable to carry out the process in a gas chamber.

[0253] FIG. 10(A) shows a perspective view of a secondary battery according to one embodiment of the present invention, which has an exterior body and a shape different from those shown in FIG. The secondary battery in FIG. 10(A) has external electrodes 771 and 772 and is made up of a plurality of packages. The device is sealed in an exterior body having a housing member.

[0254] An example of a cross section taken along the dashed line in FIG. 10(A) is shown in FIG. 10(B). The laminate having the solid electrolyte layer 750b and the negative electrode 750c is formed by providing an electrode layer 773a on a flat plate. The package member 770a is a frame-shaped package member 770b, and the electrode layer 7 The package member 770c on which the semiconductor device 73b is provided is enclosed and sealed. The package members 770a, 770b, and 770c are made of an insulating material, such as a resin material or ceramic. Mix can be used.

[0255] The external electrode 771 is electrically connected to the positive electrode 750a via the electrode layer 773a, The external electrode 772 functions as a positive terminal. It is electrically connected to electrode 750c and functions as the negative terminal.

[0256] This embodiment mode can be implemented in appropriate combination with other embodiment modes.

[0257] (Embodiment 5) 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.

[0258] [Coin-type secondary battery] First, an example of a coin-type secondary battery will be described. 11(B) is a cross-sectional view of the secondary battery of the present invention.

[0259] 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.

[0260] 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.

[0261] 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.

[0262] The negative electrode 307, the positive electrode 304, and the separator 310 are impregnated with an electrolyte, and the negative electrode 307, the positive electrode 304, and the separator 310 are then immersed in an electrolyte. As shown in Fig. 1B, the positive electrode can 301 is placed downward, and the positive electrode 304, separator 310, and negative electrode 307 are placed in the same container. The positive electrode can 301 and the negative electrode can 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. The coin-type secondary battery 300 is manufactured by crimping the battery.

[0263] 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.

[0264] Here, the flow of current during charging of the secondary battery will be explained using FIG. When a secondary battery is considered as a closed circuit, the movement of lithium ions and the flow of current go 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.

[0265] A charger is connected to the two terminals shown in FIG. 11(C), and the secondary battery 300 is charged. As the charging of the secondary battery 300 progresses, the potential difference between the electrodes increases.

[0266] [Cylindrical secondary battery] Next, an example of a cylindrical secondary battery will be described with reference to FIG. 12. Cylindrical secondary battery 60 FIG. 12(A) shows an external view of the cylindrical secondary battery 600. FIG. 12(B) shows a cross section of the cylindrical secondary battery 600. As shown in FIG. 12(B), the cylindrical secondary battery 600 has a It has a positive electrode cap (battery lid) 601 and a battery can (external can) 602 on the side and bottom. The positive electrode cap and the battery can (external can) 602 are connected by a gasket (insulating packing) )610.

[0267] 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.

[0268] 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.

[0269] 12(C), a plurality of secondary batteries 600 are mounted on a conductive plate 613 and a conductive plate 61 4 to form a module 615. The plurality of secondary batteries 600 may be connected in parallel. They may be connected in series, or may be connected in parallel and then in series. By configuring a module 615 having a plurality of secondary batteries 600, , a large amount of power can be extracted.

[0270] 12(D) is a top view of module 615. For clarity, conductive plate 613 As shown in FIG. 12(D), the module 615 is made up of a plurality of secondary batteries 600. The conductive plate may be placed on the conductive wire 616. In addition, even if a temperature control device 617 is provided between the plurality of secondary batteries 600, When the secondary battery 600 is overheated, the temperature control device 617 cools it down. If 600 is too cold, it can be heated by the temperature control device 617. Therefore, the performance of the module 615 is less affected by the outside temperature. The heat transfer medium is preferably insulating and non-flammable.

[0271] 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.

[0272] [Example of secondary battery structure] Another structural example of the secondary battery will be described with reference to FIGS.

[0273] 13(A) and 13(B) are diagrams showing the external appearance of the secondary battery. are connected to antennas 914 and 915 via circuit board 900. A label 910 is attached to the secondary battery 913. In this way, the secondary battery 913 is connected to the terminal 951 and the terminal 952 .

[0274] 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.

[0275] 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.

[0276] 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.

[0277] 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.

[0278] The structure of the secondary battery is not limited to that shown in FIG.

[0279] For example, as shown in FIGS. 14(A1) and 14(A2), In the secondary battery 913 shown in FIG. 9B, an antenna may be provided on each of a pair of opposing surfaces. FIG. 14(A1) is an external view showing one of the pair of surfaces, and FIG. 14(A2) is an external view showing one of the pair of surfaces. 13(A) and 13(B) are external views showing the other of the pair of surfaces. For the same parts as the secondary battery, please refer to the description of the secondary battery shown in Figures 13(A) and 13(B). It can be used as appropriate.

[0280] As shown in FIG. 14(A1), a layer 916 is sandwiched between one of the two surfaces of a secondary battery 913. As shown in FIG. 14(A2), an antenna 914 is provided on both sides of the secondary battery 913. An antenna 918 is provided on the opposite side with a layer 917 sandwiched therebetween. The layer 917 is, for example, a secondary battery 913. The layer 917 has a function of shielding the electromagnetic field caused by the magnetic material. It can be used.

[0281] 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.

[0282] Alternatively, as shown in FIG. 14(B1), the secondary battery 9 shown in FIG. 13(A) and FIG. 13(B) A display device 920 may be provided in the display device 13. The display device 920 is electrically connected to the terminal 911. It is not necessary to provide the label 910 in the area where the display device 920 is provided. 13(A) and 13(B), the same parts as those of the secondary battery shown in FIG. 13(A) and The explanation of the secondary battery shown in FIG. 13(B) can be used as appropriate.

[0283] 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.

[0284] Alternatively, as shown in FIG. 14(B2), the secondary battery 9 shown in FIG. 13(A) and FIG. 13(B) may be 13 may be provided with a sensor 921. The sensor 921 is connected to the terminal 911 via a terminal 922. It is electrically connected to the same part as the secondary battery shown in Fig. 13(A) and Fig. 13(B). In this regard, the description of the secondary battery shown in FIGS. 13(A) and 13(B) can be used as appropriate.

[0285] 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.

[0286] Furthermore, an example of the structure of the secondary battery 913 will be described with reference to FIGS.

[0287] The secondary battery 913 shown in FIG. 15(A) has a terminal 951 and a terminal 952 inside a housing 930. The winding 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. It is not in contact with the housing 930. For convenience, in FIG. 15(A), the housing 930 is shown separated. However, in reality, the winding body 950 is covered by the housing 930, and the terminals 951 and 952 are 52 extends outside the housing 930. The housing 930 is made of a metal material (e.g., aluminum). For example, a material such as aluminum or a resin material can be used.

[0288] As shown in FIG. 15(B), the housing 930 shown in FIG. 15(A) can be made of a plurality of materials. For example, the secondary battery 913 shown in FIG. 15B may be formed by a housing 930a and a housing The area surrounded by the housing 930a and the housing 930b is where the wound body is placed. 950 is provided.

[0289] 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.

[0290] Furthermore, the structure of the wound body 950 is shown in FIG. 16. The wound body 950 includes a negative electrode 931, 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.

[0291] The negative electrode 931 is connected to the terminal 911 shown in FIG. 13 via one of the terminals 951 and 952. The positive electrode 932 is connected to the terminal 951 shown in FIG. Connected to 11.

[0292] 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.

[0293] [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.

[0294] A laminated secondary battery 980 will be described with reference to FIG. The secondary battery 980 has a wound body 993 shown in FIG. 4, a positive electrode 995, and a separator 996. The wound body 993 is the same as that described in FIG. Similar to the wound body 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.

[0295] 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 may be designed appropriately according to the required capacitance and element volume. 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. .

[0296] As shown in FIG. 17(B), a film 981 that serves as an exterior body and a film 982 having a recess are The above-mentioned wound body 993 is housed in a space formed by bonding the above-mentioned wound body 993 and the above-mentioned wound body 82 together by thermocompression bonding or the like. By doing so, a secondary battery 980 can be fabricated as shown in FIG. 93 has a lead electrode 997 and a lead electrode 998, a film 981, and a recessed portion. The inside of the film 982 is impregnated with an electrolyte.

[0297] 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.

[0298] In addition, although Fig. 17(B) and Fig. 17(C) show examples using two films, A space is formed by folding one film, and the above-mentioned wound body 9 is inserted into the space. 93 may also be accommodated.

[0299] 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.

[0300] In addition, in FIG. 17, a secondary battery having a wound body in a space formed by a film that serves as an exterior body is shown. For example, as shown in Figure 18, the shape of the outer film is 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.

[0301] The laminated secondary battery 500 shown in FIG. 18(A) includes a positive electrode current collector 501 and a positive electrode active material. A positive electrode 503 having a material layer 502 and a negative electrode current collector 504 and a negative electrode active material layer 505 are provided. The battery includes a negative 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 housing 509. The exterior body 509 is filled with an electrolyte 508. The electrolyte 508 contains The electrolyte solution shown in Embodiment Mode 2 can be used.

[0302] In the laminated secondary battery 500 shown in FIG. 18(A), a positive electrode current collector 501 and The negative electrode current collector 504 also serves as a terminal for electrical contact with the outside. A part of the electrode current collector 501 and the negative electrode current collector 504 is exposed to the outside from the outer casing 509. In addition, the positive electrode current collector 501 and the negative electrode current collector 504 may be disposed in the outer casing 509. The lead electrode is connected to the positive electrode current collector 501 or the negative electrode current collector 502 by using the lead electrode. The lead electrode may be exposed to the outside by ultrasonic bonding to the electrode current collector 504 .

[0303] 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.

[0304] An example of the cross-sectional structure of a laminated secondary battery 500 is shown in FIG. For simplicity, (A) shows an example of a structure with two current collectors, but in reality, as shown in Figure 18(B ) it is composed of multiple electrode layers.

[0305] In FIG. 18(B), as an example, the number of electrode layers is set to 16. In FIG. 18(B), the negative electrode current collector 504 is made up of eight layers. 18(B) shows a structure of 16 layers in total, with 8 layers of the positive electrode current collector 501. The cross section of the extraction part is shown, and eight layers of negative electrode current collector 504 are ultrasonically bonded. Of course, the number of electrode layers is not limited to 16, and may be more or less. In this case, a secondary battery having a larger capacity can be obtained. In this case, a secondary battery can be made thin and highly flexible.

[0306] An example of an external view of a laminated secondary battery 500 is shown in FIGS. 19 and 20. 19 and 20 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.

[0307] 21(A) shows an external view of the positive electrode 503 and the negative electrode 506. The positive electrode 503 is connected to the positive electrode current collector 5 01, and the positive electrode active material layer 502 is formed on the surface of the positive electrode current collector 501. The electrode 503 has a region where the positive electrode current collector 501 is partially exposed (hereinafter referred to as a tab region). The electrode 506 has a negative electrode current collector 504, and the negative electrode active material layer 505 is formed on the surface of the negative electrode current collector 504. The negative electrode 506 is formed in a region where the negative electrode current collector 504 is partially exposed, i.e., a tab. The area and shape of the tab regions of the positive electrode and negative electrode are the same as those in the example shown in FIG. Not limited to.

[0308] [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. 19, will be described with reference to FIG. This will be explained using 1(B) and (C).

[0309] 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. Next, the bonding of the tab regions of the positive electrode 503 and the bonding of the tabs of the positive electrode on the outermost surface are shown. The positive electrode lead electrode 510 is bonded to the bonding region. For example, ultrasonic welding or the like is used for bonding. Similarly, the tab regions of the negative electrodes 506 are bonded to each other, and the negative electrode is bonded to the tab region of the negative electrode on the outermost surface. The lead electrode 511 is bonded.

[0310] Next, the negative electrode 506 , the separator 507 and the positive electrode 503 are placed on the exterior body 509 .

[0311] Next, as shown in FIG. 21(C), the exterior body 509 is folded at the portions indicated by the broken lines. After that, the outer periphery of the exterior body 509 is bonded. For example, thermocompression bonding may be used for bonding. At this time, a part (or one side) of the outer casing 509 is provided so that the electrolyte 508 can be poured therein later. A region (hereinafter referred to as an inlet) that is not joined to the substrate is provided.

[0312] 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.

[0313] 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.

[0314] [Bendable secondary battery] Next, an example of a bendable secondary battery will be described with reference to FIGS. 22 and 23. do.

[0315] Fig. 22(A) shows a schematic top view of a bendable secondary battery 250. 1), (B2), and (C) are the cutting lines C1-C2 and C3- in FIG. 22(A), respectively. C4 is a schematic cross-sectional view taken along the cutting line A1-A2. The battery has a positive electrode 211a and a negative electrode 211b housed inside an exterior body 251. A lead 212a electrically connected to the negative electrode 211a, and a lead 212b electrically connected to the negative electrode 211b. The cord 212b extends outside the exterior body 251. In addition to the positive electrode 211a and the negative electrode 211b, an electrolyte (not shown) is enclosed in the .

[0316] The positive electrode 211a and the negative electrode 211b of the secondary battery 250 will be explained with reference to FIG. 23(A) shows the stacking order of the positive electrode 211a, the negative electrode 211b, and the separator 214. FIG. 23(B) is a perspective view illustrating a structure in which, in addition to the positive electrode 211a and the negative electrode 211b, a FIG. 2 is a perspective view showing a lead 212a and a lead 212b.

[0317] As shown in FIG. 23(A), the secondary battery 250 includes a plurality of rectangular positive electrodes 211a, a plurality of positive electrodes 211b, and a plurality of positive electrodes 211c. The negative electrode 211b has a rectangular shape and a plurality of separators 214. Each of the positive electrodes 211a and 211b has a protruding tab portion and a portion other than the tab. A positive electrode active material layer is formed on the surface of the negative electrode 211b except for the tab. A negative electrode active material layer is formed on the portion.

[0318] The surfaces of the positive electrodes 211a on which the positive electrode active material layer is not formed and the surfaces of the negative electrodes 211b on which the negative electrode active material layer is not formed are The positive electrode 211a and the negative electrode 211b are stacked so that the surfaces on which no material layer is formed are in contact with each other. It is layered.

[0319] In addition, the surface on which the positive electrode active material layer of the positive electrode 211a is formed and the surface on which the negative electrode active material layer of the negative electrode 211b is formed are A separator 214 is provided between the formed surfaces. The separator 214 is shown by a dotted line.

[0320] As shown in FIG. 23(B), the positive electrodes 211a and the leads 212a are connected to each other at the joints 21. The negative electrodes 211b and the leads 212b are electrically connected at the joints 5a. Electrical connection is made at 215b.

[0321] Next, the exterior body 251 will be described with reference to FIGS. 22(B1), (B2), (C), and (D). do.

[0322] 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.

[0323] 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.

[0324] FIG. 22(B1) is a cross section cut at the part overlapping with the ridge line 271, and FIG. 22(B2) is 22(B1) and (B2) are cross sections cut at the part where the valley line 272 overlaps. It corresponds to a cross section in the width direction of the secondary battery 250, the positive electrode 211a and the negative electrode 211b.

[0325] 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. .

[0326] 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.

[0327] 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.

[0328] 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.

[0329] 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.

[0330] In other words, it is preferable that the distance Lb, the width Wb, and the thickness t satisfy the relationship of the following formula 1: Desirable.

[0331]

number

[0332] Here, a is 0.8 or more and 3.0 or less, preferably 0.9 or more and 2.5 or less, and more preferably The value must be between 1.0 and 2.0.

[0333] 22(C) is a cross section including the lead 212a, and shows the secondary battery 250, the positive electrode 211, 22(C), the bending portion 211a corresponds to the cross section of the negative electrode 211b in the longitudinal direction. At the end portion 261, the ends of the positive electrode 211a and the negative electrode 211b in the length direction and the outer casing 25 It is preferable to have a space 273 between the first and second electrodes.

[0334] FIG. 22(D) shows a schematic cross-sectional view of the secondary battery 250 when bent. ) corresponds to the cross section taken along the cutting line B1-B2 in FIG. 22(A).

[0335] 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.

[0336] Furthermore, as shown in FIG. 22(D), 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 211b are displaced relative to each other. The negative electrode 211b is fixed at one end on the seal portion 263 side by the fixing member 217, so that it is not broken. The deviation increases as the distance gets closer to the bent portion 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 211 As a result, the positive electrode 211a and the negative electrode 211b do not need to be able to expand or contract. Therefore, the secondary battery 250 can be bent without any trouble.

[0337] 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.

[0338] The secondary battery 250 illustrated in FIGS. 22 and 23 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.

[0339] FIG. 24(A) shows three laminated secondary batteries 500 attached to a first plate 521 and a second plate 522. 24(B) is a perspective view showing how the plate 524 is sandwiched and fixed. The first plate 521 and the second plate 522 are fixed to each other using the fixing fixtures 525a and 525b. By fixing the distance between the port 524, it is possible to apply pressure to the three secondary batteries 500. do.

[0340] 24(A) and 24(B) show an example in which three laminated secondary batteries 500 are used. However, it is not particularly limited, and four or more secondary batteries 500 may be used, and ten or more If more than 100 units are used, it can be used as a power source for small vehicles. It can also be used as a large power source. It also has a protection circuit to prevent overcharging and a temperature rise. A temperature sensor for monitoring the temperature may be provided in the laminated secondary battery 500.

[0341] In all-solid-state batteries, a certain amount of pressure is applied in the stacking direction of the stacked positive and negative electrodes. The contact state of the interface at the stacking portion can be maintained in a good condition. Applying force can suppress expansion in the stacking direction due to charging and discharging of the all-solid-state battery. This makes it possible to improve the reliability of the all-solid-state battery.

[0342] This embodiment mode can be implemented in appropriate combination with other embodiment modes.

[0343] (Sixth embodiment) In this embodiment, an example in which a secondary battery according to one embodiment of the present invention is mounted in an electronic device will be described. Reveal.

[0344] First, as explained in part of the fifth embodiment, a bendable secondary battery is mounted on an electronic device. Examples of such a battery are shown in Fig. 25(A) to Fig. 25(G). As a child device, for example, a television device (also called a television or television receiver) , computer monitors, digital cameras, digital video cameras, digital photo frame, mobile phone (also called mobile phone, mobile phone device), portable game machine, portable information Examples include information terminals, audio playback devices, and large game machines such as pachinko machines.

[0345] 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.

[0346] FIG. 25A shows an example of a mobile phone. The mobile phone 7400 has a housing 740 1, in addition to a display unit 7402, operation buttons 7403, an external connection port 7404, The mobile phone 7400 is equipped with a speaker 7405, a microphone 7406, and the like. The secondary battery 7407 is a secondary battery of one embodiment of the present invention. This allows us to provide lightweight, long-lasting mobile phones.

[0347] FIG. 25(B) shows the mobile phone 7400 in a bent state. When the entire 00 is deformed by an external force and curved, the secondary battery installed inside The secondary battery 7407 is also bent. At this time, the state of the bent secondary battery 7407 is as shown in FIG. The secondary battery 7407 is a thin storage battery. The secondary battery 7407 is bent. The secondary battery 7407 is fixed in a state where the lead electrode is 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 a contact with the current collector. This improves adhesion with the active material layer, making the secondary battery 7407 highly reliable when bent. It is composed of:

[0348] FIG. 25(D) shows an example of a bangle-type display device. The portable display device 7100 is , a housing 7101, a display unit 7102, operation buttons 7103, and a secondary battery 7104. FIG. 25(E) shows the bent state of the secondary battery 7104. When the device is bent and worn on the user's arm, the housing may deform and damage part of the secondary battery 7104 or The total curvature changes. The degree of curvature at any point on the curve is expressed as the radius of the corresponding circle. The value expressed as the radius of curvature is called the radius of curvature, and the reciprocal of the radius of curvature is called the curvature. A part of the main surface of the housing or secondary battery 7104 within the range of 40 mm to 150 mm in diameter The radius of curvature of the main surface of the secondary battery 7104 is 40 mm or more. If the thickness is within the range of 0 mm or less, high reliability can be maintained. By using the secondary battery of one embodiment of the present invention, a lightweight and long-life portable display device can be provided.

[0349] FIG. 25(F) shows an example of a wristwatch-type portable information terminal. The watch includes a housing 7201, a display unit 7202, a band 7203, a buckle 7204, and an operation button 7 205, an input / output terminal 7206, etc.

[0350] 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.

[0351] 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.

[0352] 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.

[0353] 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.

[0354] 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.

[0355] 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. 25(E) is curved and inserted into the housing 7201. The flexible support 7204 may be incorporated into the band 7203 in a flexible state or may be incorporated into the band 7203 in a flexible state.

[0356] 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.

[0357] FIG. 25G shows an example of a wristband-type display device. The display device 7300 has a display unit The display device 7300 includes a secondary battery 7304 according to one embodiment of the present invention. The display portion 7304 may be provided with a touch sensor, and may function as a portable information terminal. It is also possible to do so.

[0358] 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.

[0359] The display device 7300 is also equipped with an input / output terminal, and can be directly connected to other information terminals via a connector. It is possible to exchange data and also charge via the input / output terminal. The charging operation may be performed by wireless power supply without using the input / output terminals.

[0360] 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.

[0361] 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 with reference to FIG. 25(H), FIG. 26 and FIG.

[0362] 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.

[0363] FIG. 25(H) is a perspective view of a device also called a tobacco-containing smoking device (electronic cigarette). In FIG. 25(H), an electronic cigarette 7500 includes an atomizer 7501 including a heating element and an atomizer 7502. The secondary battery 7504 supplies power to the tomizer, and the car battery contains the liquid supply bottle, sensors, etc. To enhance safety, the secondary battery 7504 is A protection circuit for preventing over-discharge 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. The 7504 is the tip when held, so the total length is short and the weight is light. It is desirable that the secondary battery according to one embodiment of the present invention has a high capacity and good cycle characteristics. The 7500 is a small and lightweight electronic cigarette that can be used for long periods of time. We can provide it.

[0364] Next, Fig. 26(A) and Fig. 26(B) show an example of a foldable tablet terminal. The tablet terminal 9600 shown in FIGS. 26(A) and 26(B) includes a housing 963 0a, a housing 9630b, a movable part 9640 connecting the housings 9630a and 9630b, a table A display unit 9631 having a display unit 9631a and a display unit 9631b, switches 9625 to The display unit 9631 has a latch 9627, a fastener 9629, and an operation switch 9628. By using a flexible panel, the tablet terminal has a larger display area. FIG. 26(A) shows a state in which the tablet terminal 9600 is open, and FIG. (B) shows the tablet terminal 9600 in a closed state.

[0365] 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.

[0366] 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.

[0367] 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

[0368] 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.

[0369] 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.

[0370] In FIG. 26A, a display portion 9631a on the housing 9630a side and a display portion 9631b on the housing 9630b side are 9631a and 9631b have almost the same display area. The display area of ​​each of the 9631b is not particularly limited, and one size may be different from the other. The display quality may be different, e.g. one may have a higher resolution display than the other. It may also be a display panel that can display

[0371] FIG. 26(B) shows the tablet terminal 9600 in a folded state. The portable terminal 9600 includes a housing 9630, a solar cell 9633, and a DC-DC converter 9636. In addition, a charge / discharge control circuit 9634 including a power storage unit 9635 is provided. Such a power storage unit is used.

[0372] 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.

[0373] In addition, the tablet terminal 9600 shown in FIG. 26(A) and FIG. 26(B) It has the function to display various information (still images, videos, text images, etc.), calendar, date Or a function to display the time etc. on the display, or to touch input or edit the information displayed on the display Touch input function, function to control processing by various software (programs), etc.

[0374] 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.

[0375] The configuration and operation of the charge / discharge control circuit 9634 shown in FIG. A block diagram is shown in FIG. 26(C) and will be explained. In FIG. 26(C), a solar cell 9633, a power storage unit 96 35, DC-DC converter 9636, converter 9637, switches SW1 to SW3, The display unit 9631 is shown, along with a power storage unit 9635, a DC-DC converter 9636, and a The inverter 9637 and the switches SW1 to SW3 are connected to the charge / discharge control circuit 9 shown in FIG. This corresponds to 634.

[0376] 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.

[0377] 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.

[0378] Another example of electronic equipment is shown in FIG. 27. In FIG. 27, 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.

[0379] 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.

[0380] 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:

[0381] In FIG. 27, 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, 27, 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.

[0382] In addition, FIG. 27 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.

[0383] 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.

[0384] In FIG. 27, 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.

[0385] In addition, Figure 27 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.

[0386] In FIG. 27, 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.

[0387] 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

[0388] 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.

[0389] According to one embodiment of the present invention, the cycle characteristics of a secondary battery can be improved, and the reliability can be improved. Furthermore, according to one aspect of the present invention, a high-capacity secondary battery can be obtained. This improves the characteristics of the secondary battery, thereby making the secondary battery itself smaller and lighter. Therefore, the secondary battery according to one embodiment of the present invention can be used in the electronic devices described in this embodiment. By incorporating the technology into the electronic device, it is possible to create an electronic device with a longer lifespan and lighter weight.

[0390] This embodiment mode can be implemented in appropriate combination with other embodiment modes.

[0391] (Embodiment 7) 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.

[0392] When a secondary battery is installed in a vehicle, it becomes a hybrid vehicle (HEV), an electric vehicle (EV), or It will be possible to realize next-generation clean energy vehicles such as plug-in hybrid vehicles (PHEVs). do.

[0393] FIG. 28 illustrates a vehicle using a secondary battery according to one embodiment of the present invention. The automobile 8400 shown in FIG. 1 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 as the power source for driving. The hybrid vehicle is capable of using the secondary battery according to one embodiment of the present invention. This allows for a vehicle with a long driving range. The secondary battery is mounted on the floor of the vehicle in the two positions shown in Fig. 12(C) and Fig. 12(D). In addition, multiple secondary batteries shown in Figure 15 can be combined. The combined battery pack may be installed on the floor of the vehicle. 06, but also lights such as headlights 8401 and room lights (not shown). The light device can be powered.

[0394] 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.

[0395] The car 8500 shown in FIG. 28(B) has a plug-in secondary battery. It can be charged by receiving power from an external charging facility using a method such as contactless power supply. FIG. 28(B) shows a diagram of a charging device 8021 mounted on a ground and a charging system 8022 mounted on a vehicle 8500. The secondary battery 8024 is shown being charged via a cable 8022. For charging methods and connector specifications, please refer to the specifications of CHAdeMO (registered trademark) and Combo. The charging device 8021 may be a charging station installed in a commercial facility. For example, plug-in technology can be used to The secondary battery 8024 mounted on the automobile 8500 can be charged by the power supply of Charging is performed by converting AC power to DC power via a converter such as an AC / DC converter. It is possible to do so.

[0396] 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.

[0397] 28C 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. 8(C) includes a secondary battery 8602, side mirrors 8601, and a directional indicator. The secondary battery 8602 supplies electricity to the direction indicator light 8603. can be done.

[0398] In addition, the scooter 8600 shown in FIG. 28(C) has a secondary battery 86 in the storage under the seat 8604. The secondary battery 8602 can be stored in the under-seat storage 8604, which is small. The secondary battery 8602 can be stored in the under-seat storage 8604. When charging, the secondary battery 8602 is brought indoors, charged, and then stored away before driving. Just pay it.

[0399] 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.

[0400] This embodiment mode can be implemented in appropriate combination with other embodiment modes. [Example]

[0401] In this example, the positive electrode active material 100A-1, the mixture 904, and the positive electrode active material 100A-2 of the comparative example were used. 0C and evaluated the battery cell characteristics.

[0402] <Preparation of positive electrode active material> [Sample 1] As the positive electrode active material 100A-1, Sample 1 was prepared according to the flow shown in FIG. Ta.

[0403] First, a mixture 902 containing magnesium and fluorine was prepared (steps S11 to S15). Step S14) Weigh out LiF and MgF2 so that the molar ratio of LiF:MgF2 is 1:3. Acetone was added as a solvent and the mixture was mixed and crushed in a wet manner. The treatment was carried out in a ball mill using conical balls at 400 rpm for 12 hours. was collected and designated as mixture 902.

[0404] Next, nickel hydroxide, which is a metal source, is mixed with acetone to obtain finely powdered nickel hydroxide. A tube was fabricated (steps S15 to S17).

[0405] Next, aluminum hydroxide, which is a metal source, is mixed with acetone to obtain finely powdered aluminum hydroxide. Aluminum was produced (steps S18 to S20).

[0406] Next, lithium cobalt oxide was prepared as a composite oxide containing lithium and cobalt. More specifically, Cellseed C-10N manufactured by Nippon Chemical Industry Co., Ltd. was prepared (S Step S25).

[0407] Next, in step S31, the atomic weight of cobalt contained in the lithium cobalt oxide is The atomic weight of magnesium in the mixture 902 was weighed out to be 1.0%. The atomic weight of nickel in nickel oxide is the atomic weight of cobalt in lithium cobalt oxide. The amount of hydroxide was weighed out so that it was 0.5% of the sum of the amount of hydroxide and the atomic weight of nickel. The atomic weight of aluminum in aluminum is the atomic weight of cobalt in lithium cobalt oxide. The weight of the mixture was 0.5% of the sum of the atomic weight of the nickel and the atomic weight of the iron. Compound 902, nickel hydroxide, aluminum hydroxide and lithium cobalt oxide were mixed. The mixing was carried out in a dry manner using a ball mill with zirconia balls. rpm for 1 hour.

[0408] Next, the processed material was collected to obtain a mixture 903 (steps S32 and S 33).

[0409] Next, the mixture 903 was placed in an aluminum oxide crucible and heated in a muffle furnace in an oxygen atmosphere for 85 The film was annealed at 0° C. for 60 hours (step S34). The crucible was covered with a lid. The oxygen flow rate was 10 L / min. The temperature was increased at 200°C / hr and decreased at 100°C / hr. The heating was carried out for more than 10 hours. After the heating treatment, the material was collected and sieved (Step S 35), and a positive electrode active material 100A-1 was obtained (step S36).

[0410] [Sample 2] A sample was prepared using the mixture 904 as the positive electrode active material. See the part of the flow shown in Figure 3. Sample 2 was prepared.

[0411] First, a mixture 902 containing magnesium and fluorine was prepared (step S11). (up to step S14) The molar ratio of LiF and MgF2 is LiF:MgF2=1:3. The mixture was weighed, and acetone was added as a solvent, followed by wet mixing and grinding. The treatment was carried out in a ball mill using zirconia balls at 400 rpm for 12 hours. The material was collected and designated mixture 902.

[0412] Next, a positive electrode active material containing cobalt was prepared (step S25). The lithium cobalt oxide synthesized for this purpose was Cellseed C-10 manufactured by Nippon Chemical Industry Co., Ltd. CellSeed C-10N is a cobalt alloy with a D50 of approximately 12 μm and few impurities. It is lithium oxide.

[0413] Next, the mixture 902 and lithium cobalt oxide were mixed (step S31). The atomic weight of magnesium in mixture 902 is The atomic weight was weighed to be 0.5%. Mixing was done by dry mixing. The mixture was mixed in a ball mill using a roller at 150 rpm for 1 hour.

[0414] Next, the treated material was collected to obtain a mixture 903 (steps S32 and S3 3).

[0415] Next, the mixture 903 was placed in an aluminum oxide crucible and heated in a muffle furnace in an oxygen atmosphere for 85 The film was annealed at 0° C. for 60 hours (step S34). The crucible was covered with a lid. The oxygen flow rate was 10 L / min. The temperature was increased at 200°C / hr and decreased at 100°C / hr. The heating was carried out for 10 hours or more. The material after the heat treatment was collected (step S35) and sieved. The mixture 904 was obtained by the same procedure as in step S36. Compared to 1, no aluminum or nickel is added, which shortens the manufacturing process. The mixture 904 is also produced by utilizing the eutectic phenomenon, and is therefore included in one embodiment of the present invention. .

[0416] Cellseed C-10N was used as the comparative positive electrode active material 100C.

[0417] <Battery cell production> Next, Sample 1 and Sample 2 obtained above were used as positive electrode active materials. The positive electrode active materials were AB and PVDF, and the ratio of active material was AB:PV. The slurry was mixed at a weight ratio of DF=95:3:2 and coated onto the current collector. NMP was used as the solvent for the slurry.

[0418] After the slurry was applied to the current collector, the solvent was evaporated and then a pressure of 210 kN / m was applied. After this, a pressure of 1467 kN / m was applied. Through these steps, a positive electrode was obtained. The amount of electrode active material carried is approximately 20 mg / cm 2 It was decided.

[0419] Using the prepared positive electrode, a CR2032 type (diameter 20 mm, height 3.2 mm) carp was We fabricated a battery cell with a 1000-milliwatt capacity.

[0420] The counter electrode was made of lithium metal.

[0421] The electrolyte contained 1 mol / L of lithium hexafluorophosphate (LiPF6). The electrolyte used was ethylene carbonate (EC) and diethyl carbonate (DEC). The mixture was EC:DEC = 3:7 (volume ratio). The secondary batteries tested contained 2 wt% vinylene carbonate (VC) in the electrolyte. did.

[0422] The separator was made of polypropylene with a thickness of 25 μm.

[0423] The positive electrode can and the negative electrode can were made of stainless steel (SUS).

[0424] <Cycle characteristics> The obtained positive electrode active material 100A-1, the mixture 904, and the positive electrode active material 100C of the comparative example were Battery cells were fabricated using each material and the cycle characteristics (45°C) were measured. The results are shown in Figure 29 and Figure 30. Figure 29 is a graph with the discharge capacity on the vertical axis and the number of cycles on the horizontal axis. Using the same measurement results, a graph is shown in FIG. 31, with the capacity retention rate on the vertical axis and the number of cycles on the horizontal axis. In addition, all the samples used in FIGS. 29 and 31 had a positive electrode active material loading of 7 mg / cm 2 It was decided.

[0425] The cycle characteristics were measured under the conditions of CCCV (0.5C, 4.6V) at 45°C. The battery was repeatedly charged and discharged at CC (0.5C, 2.5V). The C rate was set to 200 mA / g.

[0426] As shown in FIG. 31, the positive electrode active material 100A-1 and the mixed positive electrode active material 100B-1 were significantly higher than the positive electrode active material 100C of the comparative example. The positive electrode active material 100A has a significantly higher capacity retention rate after 50 cycles. The capacity retention rate of mixture 904 was approximately 79%. After 0 cycles, the positive electrode active material 100A-1 maintained approximately 10% more capacity than the mixture 904. The retention rate has improved.

[0427] Next, the cathode active material 100A-1, the mixture 904, and the cathode active material 100C of the comparative example were compared. The results of measuring the cycle characteristics (25°C) of battery cells made using these materials are shown in Figure 32(A). The cycle characteristics were measured under the conditions of charging at 25°C. CCCV (0.5C, 4.6V, final current 0.05C), discharge CC(0.5C, 2.5 The charge and discharge were repeated at a rate of 200 mA / g. The graph shows the discharge capacity on the left axis and the number of cycles on the right axis. (B) shows a graph in which the capacity retention rate is on the vertical axis and the number of cycles is on the horizontal axis. All the samples used in FIG. 32(B) had a positive electrode active material loading of 7 mg / cm 2 year Ta.

[0428] As shown in FIG. 32(A), the positive electrode active material 100A-1 is superior to the positive electrode active material 100C of the comparative example. Mixture 904 has a significantly higher capacity retention rate. The capacity retention rate of 00A-1 was approximately 98%, and that of mixture 904 was approximately 96%. Ta.

[0429] <Rate characteristics> Regarding secondary batteries using mixture 904, positive electrode active material 100A-1, and a comparative example, The results of the rate characteristic evaluation are shown in Table 1.

[0430] [Table 1]

[0431] The coin cell for evaluating rate characteristics had a positive electrode active material layer loading of 8 mg / cm 2 and density 3 .8g / cc or more, LCO:AB:PVDF blend ratio 95:3:2, electrolytic The substrate is 1 mol / L lithium hexafluorophosphate (LiPF6), and the electrolyte is ethyl acetate. Ethylene carbonate (EC) and diethyl carbonate (DEC) were mixed in a ratio of EC:DEC=3:7 ( The electrolyte was mixed with vinylene carbonate (VC). 2 wt% was added.

[0432] The upper limit for the initial charge is 4.5V or 4.6V, and the following conditions are met: CCCV, 0.2C, 4.6V, The cut-off current was 0.02 C. The first discharge was CC, 0.2 C, and the cut-off voltage was 2.5 V. Here, 1C is a current value per weight of the positive electrode active material of 200 mA / g. From the second charge and discharge onwards, only the discharge rate was changed, 0.2C charge / 0.2C discharge, 0.2 C charge / 0.5C discharge, 0.2C charge / 1.0C discharge, 0.2C charge / 2.0C discharge, 0 .2C charge / 3.0C discharge, 0.2C charge / 4.0C discharge, 0.2C charge / 5.0C discharge The measurement was performed in this order with a 10-minute rest period and at a temperature of 25°C.

[0433] As can be seen from Table 1, the comparative example had a large capacity deterioration, and the sample using mixture 904 and the normal The sample using the electrode active material 100A-1 showed little deterioration.

[0434] <Powder resistivity and conductivity> Powder resistance and The conductivity was measured using a measuring device, MCP-PD51 manufactured by Mitsubishi Chemical Analytech Co., Ltd. The four-probe method was performed using either Loresta GP or Hiresta GP. The volume resistivity of 904 is 8.2.E+04 (Ω·cm) and the conductivity is 1.2.E-0 The volume resistivity of the positive electrode active material 100A-1 was 8.0E+. The resistance was 1.3E-07 (Ω·cm) and the conductivity was 1.3E-08 (S / cm). The volume resistivity of the example is 9.9E+02 (Ω·cm) and the conductivity is 1.0E-03 ( The volume resistivity and conductivity were measured when a load of 20 kN was applied to the powder. It is a fixed value.

[0435] In addition, when the composite layer of Mixture 904 was measured using a HIOKI electrode resistance measuring device, it was found to be 0. 9 (Ω·cm), and the interface resistance is 0.003 (Ω·cm 2 ) In addition, the positive electrode activity When the composite layer of material 100A-1 was measured, the interfacial resistance was 1.6 (Ω·cm). 0.005(Ω·cm 2 ) Furthermore, when the mixture layer of the comparative example was measured, it was 4.2 ( Ω·cm), and the interface resistance is 0.009(Ω·cm 2 ) was.

[0436] <Continuous charging durability> Next, the obtained positive electrode active material 100A-1, the mixture 904, and the positive electrode active material 100A-1 of the comparative example were mixed. Battery cells were fabricated using each of the materials C and the results of measuring the continuous charge durability are shown in FIG. In addition, all samples used in Figure 30 had a positive electrode active material loading of 20 mg / cm 2 and .

[0437] As a measurement condition for continuous charge tolerance, first, charge is CCCV (0.2C, 4.5V, final current 0.02C), discharge CC (0.2C, 2.5V) at 25°C for one cycle 1C was set to 191.7mA / g.

[0438] After that, charging was performed at 60°C with CCCV (0.5C). The upper limit voltage of 4.6V was reached. Then it becomes CV charging, the current value gradually decreases, then stabilizes at a low current value, and then the current value Measurements were continued until the current value increased significantly. If it rises, it may be due to a short circuit or other problem. The value was set to 0.7mA / g.

[0439] 136 hours of continuous charge time compared to 74 hours for Mix 904 The positive electrode active material 100A-1 showed better results. This refers to the time obtained by subtracting the full charge time from the short circuit time.

[0440] A positive electrode active material that combines both cycle characteristics at 45°C and continuous charging resistance is essential for the reliability of secondary batteries. From these experimental results, it was found that the positive electrode active material 100A-1 was the best. It can also be said to be an excellent material. [Example]

[0441] In this example, a coin-type half-cell sample was prepared using the positive electrode active material 100A-2. The measurement conditions were changed to 45℃, 65℃, and 85℃, and the cycle characteristics (50 The results are shown in Figure 34(A). Other measurement conditions were a charging voltage of 4 .6V, charging CCCV (0.5C, final current 0.05C), resting for 10 minutes, discharging CC( The voltage was 0.2 C, 2.5 V, and the C rate was 200 mA / g.

[0442] In addition, the cycle characteristics (50 cycles) were measured when the charging voltage was set to 4.4V. is shown in Figure 34(B).

[0443] In addition, all the samples used in Figures 34(A) and 34(B) had a positive electrode active material loading amount 7 mg / cm 2 , density 3.8g / cc or more, LCO:AB:PVDF blend ratio 95:3: 2. Lithium bis(fluorosulfonyl)amide (Li(FSO2)2N) as electrolyte, The EMI-FSA solution was prepared by dissolving 1.5 mol / L of LiFSA. The chemical formula of I-FSA is shown below.

[0444] [ka]

[0445] The electrolyte used in this example partially decomposes at 85°C, so the cycle at 85°C was The electrolyte used in this example contains multiple types of materials. When one of these combinations or their ratios is used, some of the components will separate at 85°C. It is simply dissolved, and the combination or ratio can be changed by adding other additives. This may result in an electrolyte that does not partially decompose at 85°C. [Example]

[0446] In this example, a different electrolyte from that in Example 2 was used, and the cycle when the charging voltage was 4.4 V was The characteristics of the battery were measured (50 cycles).

[0447] The electrolyte used in the electrolytic solution is 1 mol / L lithium hexafluorophosphate (LiPF6). The electrolyte is ethylene carbonate (EC) and diethyl carbonate (DEC). The electrolyte was a mixture of ethylenediaminetetraacetic acid (DEC) and vinylene glycol (VPE) at a volume ratio of 3:7. Carbonate (VC) was added at 2 wt%.

[0448] A coin-type half-cell sample was prepared using the positive electrode active material 100A-3, and the measurement conditions were as follows: The cycle characteristics (50 cycles) were measured under different conditions, 45°C and 85°C. The results are shown in FIG. 35(A). A sample of the battery was prepared, and the cycle characteristics (50 cycles) were measured at 65°C. The results are shown in FIG. 35(B).

[0449] The flow diagram for obtaining the positive electrode active material 100A-3 is shown in FIG. 37. The flow in FIG. The mixture is the same up to the mixture 904 obtained in step 6, and then the nickel obtained in steps S41 to S43. The Kel mixture and the aluminum mixture obtained in S44 to S46 are mixed in S53. Then, through steps S53 to S57, positive electrode active material 100A-3 is obtained in step S58. do.

[0450] As a comparative example, lithium cobalt oxide particles (product name: Cellseed C-10) were used as the positive electrode active material. N) to prepare a coin-type half-cell sample, and the sample was measured at a charging voltage of 4.4V. The cycle characteristics (50 cycles) were measured, and the results are shown in Figure 36.

[0451] In Figures 35(A) and 35(B), the results at 45°C and 65°C are almost the same. In addition, in FIG. 35(A), the The cycle characteristics at 85°C are superior to those of the comparative example shown in FIG. do. [Example]

[0452] In this example, the cycle characteristics (50 cycles) when the charging voltage was 4.6 V, which is different from that in Example 3, were measured. The cycle was measured.

[0453] In this example, a positive electrode active material 100A-1 and a mixture 904 were prepared, and the characteristics of the battery cell were evaluated. The sample prepared according to the flow chart shown in FIG. 1 for obtaining the positive electrode active material 100A-1 was measured. The conditions for producing the positive electrode active material 100A-1 were as follows: Lithium fluoride particles (C-10N), magnesium fluoride, lithium fluoride, nickel hydroxide Nickel and aluminum hydroxide were mixed together and then annealed (80°C under oxygen gas flow). The cathode active material 100A-1 was magnesium fluoride. The molar ratio of magnesium in lithium fluoride to lithium in lithium fluoride is 0.33. 100 times the amount of nickel in nickel hydroxide, 0.5 times the amount of aluminum in aluminum hydroxide The lithium cobalt oxide particles manufactured by Nippon Chemical Industry Co., Ltd. were weighed so that the amount of the lithium was 0.5 times that of the ammonium hydroxide. (Product name: Cell Seed C-10N) and mix.

[0454] The obtained positive electrode active material 100A-1, AB and PVDF were mixed in a ratio of AB:PVDF=95 The slurry was mixed in a weight ratio of 3:2 and applied to a current collector, which was then pressed to form the positive electrode. The results are shown in Figure 38. The white circles in Figure 38 represent the positive electrode active material 100A of this example. The black circle indicates the mixture 904. Also, in FIG. 0 mg / cm 2 The mixture 904 is also good, but the positive electrode active material The value of 100A-1 shows a better value.

[0455] The measurement conditions were 25°C and the loading was 20 mg / cm 2 The density was set to 3.8 g / cc or more.

[0456] The electrolyte used in the electrolytic solution is 1 mol / L LiPF6, and the electrolytic solution is ethylene carbonate. Carbonate (EC) and diethyl carbonate (DEC) are mixed in a volume ratio of 3:7. The electrolyte solution was mixed with 2 wt% vinylene carbonate (VC). Added.

[0457] Also, dQ / dVvs, which represents the change in voltage relative to the charge capacity, was calculated from the data in Figure 38. The V curve is shown in Figure 39. In Figure 39, a small peak is observed at about 4.55 V. However, it was not clear. In the dQ / dV vs V curve shown in Figure 39, some peaks were extremely In such cases, two crystal structures coexist. For example, two phases of O3 and pseudospinel coexist, or two phases of pseudospinel and H1-3 coexist. There is a possibility that they are in phase coexistence, etc. [Example]

[0458] In this example, a sample was prepared according to the flow chart shown in FIG. 3 for obtaining the positive electrode active material 100A-2. The process for producing the positive electrode active material 100A-2 was to first mix cobalt in a dry ball mill. Lithium fluoride particles (C-10N), magnesium fluoride, and lithium fluoride were mixed. After that, the mixture was heat treated at 850°C for 60 hours, and the resulting mixture was mixed with nickel hydroxide and dry ball mill. Then, the sol-gel method is applied, and aluminum isopropanol is used as the metal source. The cid was mixed with isopropanol as a solvent and then heated at 850°C for 2 hours. The obtained positive electrode active material 100A-2, AB, and A slurry of AB and PVDF mixed at a weight ratio of 95:3:2 was prepared. The coated current collector was used as the positive electrode. 2 In addition, X To make the RD peaks easier to see, the electrodes were not pressed.

[0459] Mixture 904 was used as a comparative example. The mixture is made of aluminum particles (C-10N), magnesium fluoride, and lithium fluoride. The temperature was 850°C for 60 hours.

[0460] The electrolyte of each sample secondary battery is ethylene carbonate (EC) and diethylene A mixture of ethylenediamine dicarbonate (EC) and diethyl ether (DEC) at a volume ratio of 3:7 was used. Ta.

[0461] The secondary battery using the positive electrode active material 100A-2 or the mixture 904 was charged at 4.6 V by CCCV. Specifically, after charging at a constant current of 0.5C up to 4.6V, the current value was reduced to 0.01C. The charged secondary battery was then placed in an argon atmosphere in a glove box. The cathode is removed by disassembling it inside the container, and the electrolyte is removed by washing it with DMC (dimethyl carbonate). The sample was then placed in a sealed container under an argon atmosphere and subjected to XRD analysis. The cathode was measured using a Bruker D8 Advance. Powder XRD analysis was carried out using a powder XRD. The XRD was measured by sealing the sample in a sealed container under an argon atmosphere. The pole was attached to a glass plate to maintain flatness. The height of the sample was adjusted to fit the measurement surface required by the instrument.

[0462] The CuKα1 line calculated from the pseudo-spinel crystal structure and H1-3 crystal structure model The ideal powder XRD patterns are shown in Figures 40 and 41. For comparison, the charge depth is also shown. The ideal XRD pattern calculated from the crystal structure of CoO2(O1) of 1 is also shown. The pattern of CoO2(O1) is ICSD (Inorganic Crystal Structure Diagram). The crystal structure information was obtained from the Materials Reflex Powder, one of the modules in Studio (BIOVIA) The 2θ range was 15° to 75°, and the St ep size=0.01, wavelength λ1=1.540562 Å, λ2 is set None, Monochromator was single. H1-3 type crystal structure pattern The pattern was similarly created from the crystal structure information described in Non-Patent Document 3. The pseudospinel pattern was The crystal structure of the positive electrode active material according to one embodiment of the present invention was estimated from the XRD pattern, and the crystal structure was analyzed using TOPAS ver. .3 (Bruker crystal structure analysis software) was used for fitting, and the results were the same as those of other The XRD patterns were generated in the same manner.

[0463] After charging the secondary battery using the positive electrode active material 100A-2 or the mixture 904 at 4.65 V The XRD patterns of the positive electrodes are also shown. For comparison, the pseudospinel crystal structure and H1-3 The crystal structure pattern is also shown.

[0464] Figure 40 shows the XRD pattern on the low angle side, and Figure 41 shows the XRD pattern on the high angle side. This shows the

[0465] Both the mixture 904 and the positive electrode active material 100A-2 were mostly pseudospinel at 4.6 V charge. When charged at a charging voltage of 4.65 V, the mixture 904 exhibited a H1 The peaks of the CoO2(O1) type crystal structure were observed along with the -3 type crystal structure. The peak was broad, suggesting that the crystallinity had decreased significantly.

[0466] On the other hand, the positive electrode active material 100A-2 showed no pseudo-spin even at charging voltages of 4.6V and 4.65V. Therefore, the positive electrode active material 100A-2 has a more It is believed that the cycle characteristics are good.

[0467] In addition, to explain in more detail the structural change from the crystal structure (R-3m) in the discharged state, 2 and 43 are used. Figure 42 shows the results of the positive electrode active material 100A-2 before charging, when it was charged to 4.5 V, and when it was charged to 4 Figure 43 shows the XRD patterns of the commercially available 1000mAh lithium ion battery at 0.55V and 4.6V. XRD patterns of LCO before charging, at 4.5V, 4.55V, and 4.6V Indicates a turn.

[0468] In Figure 43, large changes to H1-3 are observed at multiple locations on both the low-angle and high-angle sides. At around 37°C, a new peak due to stacking misalignment appears at 4.55V and 4.6V charging states. In the comparative example in Figure 43, the crystal structure is destroyed by charging.

[0469] On the other hand, in Figure 42, no significant change in the peak is observed, which indicates that the shift in the Co-O layer is small. This means that the crystal structure is less likely to collapse. [Explanation of symbols]

[0470] 100 Cathode active material 100A-1 Cathode active material 100A-2 Cathode active material 100A-3 Cathode active material 100C Comparative positive electrode active material 200 Active material layer 201 Graphene Compounds 211a positive electrode 211b negative electrode 212a Lead 212b Lead 214 Separator 215a Joint 215b Joint 217 Fixing member 250 Secondary battery 251 Exterior body 261 Bending part 262 Seal part 263 Seal part 271 Ridgeline 272 Valley Line 273 Space 300 Secondary battery 301 Positive electrode can 302 Anode can 303 Gasket 304 Positive electrode 305 Positive electrode current collector 306 Positive electrode active material layer 307 Negative electrode 308 Negative electrode current collector 309 Negative electrode active material layer 310 Separator 400 Secondary battery 410 Positive electrode 411 Cathode active material 413 Positive electrode current collector 414 Cathode active material layer 420 Solid electrolyte layer 421 Solid electrolyte 430 negative electrode 431 Negative electrode active material 433 Negative electrode current collector 434 Negative electrode active material layer 440 board 441 Wiring electrode 442 Wiring electrode 500 secondary battery 501 Positive electrode current collector 502 Positive electrode active material layer 503 Positive electrode 504 Negative electrode current collector 505 Negative electrode active material layer 506 negative electrode 507 Separator 508 Electrolyte 509 Exterior body 510 Positive lead electrode 511 Negative lead electrode 521 Plate 524 Plate 525a Fixtures 525b Fixtures 600 Secondary battery 601 Positive electrode cap 602 Battery can 603 Positive terminal 604 Positive electrode 605 Separator 606 negative electrode 607 Negative terminal 608 Insulating plate 609 Insulating board 611 PTC element 612 Safety valve mechanism 613 Conductive Plate 614 Conductive Plate 615 Module 616 Conductor 617 Temperature Control Device 750a positive electrode 750b solid electrolyte layer 750c negative pole 751 Electrode Plate 752 Insulating tube 753 Electrode Plate 761 Lower member 762 Upper member 763 Cap screw 764 Wing Nut 765 O-ring 766 Insulator 770a Packaging material 770b Packaging material 770c packaging material 771 External electrode 772 External electrode 773a Electrode layer 773b Electrode layer 900 Circuit Board 901 mixture 902 mixture 903 mixture 904 Mixture 905 mixture 910 Label 911 terminal 912 circuits 913 Secondary battery 914 Antenna 915 Antenna 916 layers 917 layers 918 Antenna 920 Display device 921 Sensor 922 terminal 930 chassis 930a housing 930b housing 931 negative electrode 932 Positive electrode 933 Separator 950 Wound body 951 terminal 952 terminals 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 devices 7101 Housing 7102 Display section 7103 Operation button 7104 Secondary battery 7200 Personal Digital Assistant 7201 Case 7202 Display section 7203 band 7204 Buckle 7205 Operation button 7206 Input / output terminal 7207 Icon 7300 display device 7304 Display section 7400 mobile phone 7401 Housing 7402 Display section 7403 Operation button 7404 External connection port 7405 Speaker 7406 Microphone 7407 Secondary battery 7500 e-cigarettes 7501 Atomizer 7502 Cartridge 7504 Secondary battery 8000 display device 8001 Case 8002 Display section 8003 Speaker section 8004 Secondary battery 8021 Charging device 8022 cable 8024 Secondary battery 8100 Lighting equipment 8101 Housing 8102 Light source 8103 Secondary battery 8104 Ceiling 8105 Side wall 8106 beds 8107 Window 8200 indoor unit 8201 Housing 8202 Ventilation outlet 8203 Secondary battery 8204 Outdoor unit 8300 Electric refrigerator-freezer 8301 Housing 8302 Refrigerator door 8303 Freezer door 8304 Secondary battery 8400 Automobiles 8401 Headlight 8406 Electric motor 8500 cars 8600 Scooter 8601 Side mirror 8602 Secondary battery 8603 Turn signal light 8604 Under-seat storage 9600 tablet device 9625 Switch 9627 Switch 9628 Operation Switch 9629 Fasteners 9630 chassis 9630a housing 9630b housing 9631 Display section 9631a Display section 9631b Display section 9633 Solar Cells 9634 Charge / Discharge Control Circuit 9635 Electricity storage unit 9636 DC / DC Converter 9637 Converter 9640 Moving parts

Claims

1. a first step of finely pulverizing magnesium fluoride, lithium fluoride, a nickel source, and an aluminum source, and then mixing the resulting powder with lithium cobalt oxide to form a first mixture; a second step of heating the first mixture to form a second mixture; the heating temperature in the second step is 700°C or higher and 950°C or lower; the nickel source is nickel hydroxide; the aluminum source is aluminum hydroxide or aluminum isopropoxide; In the first mixture, the ratio of the number of cobalt atoms to the number of magnesium atoms is cobalt atomic number:magnesium atomic number=1:y (0.005≦y≦0.05). A method for producing a positive electrode active material.

2. a first step of finely pulverizing magnesium fluoride and lithium fluoride and then mixing them with lithium cobalt oxide to form a first mixture; a second step of heating the first mixture to form a second mixture; a third step of finely pulverizing a nickel source and then mixing it with the second mixture to form a third mixture; a fourth step of mixing an aluminum source with the third mixture to form a fourth mixture; a fifth step of heating the fourth mixture to form a fifth mixture; the nickel source is nickel hydroxide; the aluminum source is aluminum hydroxide or aluminum isopropoxide; In the first mixture, the ratio of the number of cobalt atoms to the number of magnesium atoms is cobalt atomic number:magnesium atomic number=1:y (0.005≦y≦0.05). A method for producing a positive electrode active material.

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