Method for producing positive electrode active material

Abstract

To provide a manufacturing method of a positive electrode active material of a lithium ion secondary battery.SOLUTION: A method for manufacturing a positive electrode active material includes a first step of placing a first container containing a mixture of a lithium oxide, a fluoride, and a magnesium compound in a heating furnace, a second step of making the inside of the heating furnace an atmosphere containing oxygen, and a third step of heating the inside of the heating furnace, in which the third step is performed after the first step and the second step are performed. Before the inside of the heating furnace is heated, the atmosphere in the heating furnace is preferably made to contain oxygen. More preferably, the fluoride is lithium fluoride and the magnesium compound is magnesium fluoride.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] One aspect of the present invention relates to a method for producing a positive electrode active material. Pertaining to a machine, manufacture, or composition of matter. One embodiment of the present invention is a semiconductor device, a display device, a light-emitting device, a power storage device, a lighting device, an electronic device, Or it relates to a method for producing them.

[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 silicon-ion capacitors, all-solid-state batteries, and electric double-layer capacitors.

[0003] In addition, in this specification, the term "electronic device" refers to a device in general 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, lithium-ion secondary batteries, lithium-ion capacitors, air batteries, and other all-solid-state batteries have become popular. The development of various types of energy storage devices is actively underway, especially lithium-ion batteries, which have high output and capacity. Secondary batteries are used in portable information terminals such as mobile phones, smartphones, and laptop computers. terminals, portable music players, digital cameras, medical equipment, or hybrid vehicles (HV), electric vehicles Next generation electric vehicles (EV) or plug-in hybrid vehicles (PHV or PHEV) 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] Therefore, in order to improve the cycle characteristics and increase the capacity of lithium-ion secondary batteries, Improvements to the active material have been investigated (Patent Documents 1 and 2).

[0006] In addition, the characteristics required for energy storage devices include safety in various operating environments and long-term reliability. Improvements include: [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-018914 [Patent Document 2] Japanese Patent Application Laid-Open No. 2016-076454 [Non-patent literature]

[0008] [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 Summary of the Invention [Problem to be solved by the invention]

[0009] Lithium ion secondary batteries and the positive electrode active materials used therein have various characteristics, such as capacity, cycle characteristics, Improvements are desired in various aspects such as charge / discharge characteristics, reliability, and safety, and LiCoO2 Development of a lithium composite oxide LiMO2 in which part of the lithium is replaced with a different element is underway. There is also a need to develop a method for producing LiMO2 cheaply and quickly.

[0010] In view of the above, an object of one embodiment of the present invention is to provide a method for manufacturing a positive electrode active material. Another object of one embodiment of the present invention is to provide a novel positive electrode active material. An object of one embodiment is to provide a novel power storage device.

[0011] 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]

[0012] In one aspect of the present invention, a mixture of lithium oxide, fluoride and magnesium compound is added to a heating furnace. a first step of placing a first container containing the compound; and a second step of creating an oxygen-containing atmosphere inside the heating furnace. and a third step of heating the inside of the heating furnace, and This is a method for producing a positive electrode active material, in which the third step is carried out after the first step.

[0013] In another aspect of the present invention, a lithium oxide, a fluoride, and a magnesium compound are mixed in a heating furnace. A first step of disposing a first container containing a mixture of materials, evacuating the inside of a heating furnace, and then The method includes a second step of introducing a nitrogen gas into the furnace and a third step of heating the inside of the furnace. and the second step, and then the third step.

[0014] In the above structure, the fluoride is preferably lithium fluoride (LiF).

[0015] In the above configuration, the inside of the heating furnace is preferably heated to 735°C or more and 1000°C or less. It's nice.

[0016] In the above configuration, the magnesium compound is preferably magnesium fluoride (MgF2). It's nice.

[0017] In the above configuration, it is preferable that the first container is covered with a lid. [Effects of the Invention]

[0018] According to one embodiment of the present invention, a method for manufacturing a positive electrode active material can be provided. According to one embodiment, novel positive electrode active material particles can be provided. Therefore, a novel power storage device can be provided. [Brief explanation of the drawings]

[0019] [Figure 1] FIG. 1 is a diagram illustrating an example of a method for producing a positive electrode active material. [Figure 2] FIG. 2 is a diagram illustrating the results of DSC measurement of a mixture of LiF and MgF2. [Figure 3] 3A and 3B illustrate a method for manufacturing a positive electrode active material of one embodiment of the present invention. [Figure 4] 4A and 4B illustrate a method for manufacturing a positive electrode active material of one embodiment of the present invention. [Figure 5] 5A and 5B illustrate a method for manufacturing a positive electrode active material of one embodiment of the present invention. [Figure 6] FIG. 6 is a diagram illustrating an example of a method for producing a positive electrode active material. [Figure 7] FIG. 7 is a diagram illustrating an example of a method for producing a positive electrode active material. [Figure 8] FIG. 8 is a diagram illustrating an example of a method for producing a positive electrode active material. [Figure 9] FIG. 9 is a diagram illustrating the crystal structure and magnetism of the positive electrode active material. [Figure 10] FIG. 10 is a diagram illustrating the crystal structure and magnetism of a conventional positive electrode active material. [Figure 11] 11A and 11B are cross-sectional views of an active material layer in which a graphene compound is used as a conductive additive. [Figure 12] 12A and 12B are perspective views illustrating a coin-type secondary battery. [Figure 13] 13A is a perspective view illustrating a cylindrical secondary battery, FIG. 13B is an exploded perspective view, FIG. 13C is a perspective view of the cylindrical secondary battery, and FIG. 13D is a top view illustrating the cylindrical secondary battery. [Figure 14] 14A and 14B are diagrams illustrating an example of a secondary battery. [Figure 15] 15A, 15B, 15C, and 15D are perspective views illustrating examples of secondary batteries. [Figure 16] 16A and 16B are perspective views illustrating an example of a secondary battery. [Figure 17] 17A and 17B are perspective views illustrating an example of a secondary battery. [Figure 18] FIG. 18 is a perspective view illustrating an example of a secondary battery. [Figure 19] 19A, 19B, and 19C are perspective views illustrating a laminated secondary battery. [Figure 20] FIG. 20A is a top view illustrating a laminated secondary battery, and FIG. 20B is a cross-sectional view illustrating a laminated secondary battery. [Figure 21] FIG. 21 is a diagram showing the appearance of a secondary battery. [Figure 22] FIG. 22 is a diagram showing the appearance of a secondary battery. [Figure 23] 23A, 23B, and 23C are diagrams illustrating a method for manufacturing a secondary battery. [Figure 24] FIG. 24A is a top view of a bendable secondary battery, and FIGS. 24B, 24C, 24D, and 24E are cross-sectional views illustrating the secondary battery. [Figure 25] 25A and 25B are perspective views illustrating a bendable secondary battery. [Figure 26] Figures 26A and 26B are perspective views illustrating an example of an electronic device, Figure 26C is a perspective view of a secondary battery, Figure 26D is a diagram illustrating an example of an electronic device, Figure 26E is a perspective view of a secondary battery, and Figures 26F and 26G are diagrams illustrating an example of an electronic device. [Figure 27] 27A and 27B are top views illustrating an example of an electronic device, and FIG. 27C is a block diagram. [Figure 28] FIG. 28 is a diagram illustrating an example of an electronic device. [Figure 29] FIG. 29A is a perspective view of the vehicle, FIG. 29B is a perspective view showing the vehicle during charging, and FIG. 29C is a perspective view for explaining the electric motorcycle. [Figure 30] 30A and 30B are diagrams illustrating the alumina crucible used during annealing. [Figure 31] FIG. 31 is a diagram illustrating the cycle characteristics according to the example. [Figure 32] FIG. 32 is a diagram illustrating the cycle characteristics according to the example. DETAILED DESCRIPTION OF THE INVENTION

[0020] 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.

[0021] In addition, crystal planes and directions are indicated by superscript bars in crystallography. The crystal planes and directions in the above are indicated by a bar instead of a number due to limitations in the application notation. , and are expressed by adding a - (minus sign) before the number. Also, individual orientations that indicate directions within the crystal is [ ], collective orientation indicating all equivalent directions is < >, individual faces indicating crystal faces are ( ) and the sets of surfaces with equivalent symmetry are represented by {}.

[0022] In this specification, an atmosphere containing a fluoride refers to an atmosphere in which at least one of the constituent components contains a fluoride. An atmosphere of a mixed gas containing fluorides.

[0023] (Embodiment 1) Using Fig. 1, lithium composite oxide LiMO2 (M is two or more metals including Co) (There is no particular limitation on the substitution position of the metal.) An example of a method for producing LiM is explained below. A positive electrode active material containing Mg as a metal element other than Co contained in O2 will be described as an example.

[0024] First, a halogen source is prepared as a material for the mixture 902. The halogen source may be a chloride, Bromides and iodides can be used, but fluorides are preferred. In this case, LiF, a fluorine source, is prepared as a halogen source. LiF is a common compound with LiCoO2. LiF is preferred because it has a cation. LiF can be used as both a lithium source and a fluorine source. In addition, LiF has a relatively low melting point of 848°C, and it melts during the annealing process described below. Similarly, the magnesium source used for LiMO2 is preferably The halogen source may be LiCl, MgF2, or the like. MgCl2 can also be used as a magnesium source. As a combination of sources, a combination with a eutectic point is used because the melting point depression described below can be utilized. The halogen source that can be used in one embodiment of the present invention is LiF and LiC. The magnesium source that can be used in one embodiment of the present invention is not limited to MgF 2 and MgCl2.

[0025] In this specification, the eutectic point is the point at which two components form a solid solution on the solid-liquid curve of the two components. For example, two metal elements A and B are When melted, A and B do not form a solid solution, but form separate solid phases or molecular compounds. However, when A and B are completely soluble in the liquid phase, the mixture of A and B has a higher melting point than A or B alone. The melting point is lower than that of the mixture with a certain concentration ratio of A and B. This temperature is called the eutectic point, and this mixture is also called a eutectic mixture. Instead, it may be three, four, five or more components.

[0026] In this embodiment, LiF, which is a fluorine source, is prepared as the halogen source. MgF2 is prepared as a source of Li and magnesium (Step S11 in FIG. 1). The molar ratio of F to MgF2 is preferably LiF:MgF2=u:1 (0≦u≦1.9). Preferably, LiF:MgF2=u:1 (0.1≦u≦0.5) is more preferable, and LiF:M More preferably, gF2=u:1 (u=near 0.33).

[0027] 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 does not easily react with lithium. In this embodiment, acetone is used (see step S11 in FIG. 1).

[0028] 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.

[0029] The mixed and crushed materials are collected (step S13 in FIG. 1) to obtain a mixture 902 ( Step S14 in Figure 1).

[0030] The mixture 902 has, for example, an average particle diameter (D50) of 600 nm or more and 20 μm or less. It is preferable that the particle size is 1 μm or more and 10 μm or less. If the mixture 902 is obtained, it is possible to use lithium, transition metals, and When mixed with a complex oxide containing oxygen, the mixture 902 is formed on the surface of the complex oxide particles. The mixture 902 is uniformly adhered to the surface of the composite oxide particles. After heating, halogen and magnesium are thoroughly distributed in the surface layer of the composite oxide particles. If there is a region in the surface layer that does not contain halogen and magnesium, There is a risk that the pseudospinel crystal structure described below may not be easily formed in the charged state.

[0031] <Step S25> 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.

[0032] 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 (GD-MS), the impurity concentration It is preferably 10,000 ppm wt or less, and more preferably 5000 ppm wt or less. It is particularly preferable that the total impurity concentration of transition metals such as titanium and arsenic is 3000 ppm or less. It is preferably 1500 ppm wt or less, and more preferably 1500 ppm wt or less.

[0033] 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) is approximately 12 μm, and impurity analysis by glow discharge mass spectrometry is In this case, the magnesium concentration and fluorine concentration are 50 ppm wt or less, the calcium concentration, Aluminum and silicon concentrations are 100 ppm wt or less, and nickel concentrations are 150 ppm wt or less, sulfur concentration 500 ppm wt or less, arsenic concentration 1100 ppm wt or less t or less, and the concentration of elements other than lithium, cobalt and oxygen is 150 ppm wt or less Below is lithium cobalt oxide.

[0034] 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.

[0035] Next, the mixture 902 is mixed with a composite oxide containing lithium, a transition metal, and oxygen. (Step S31 in FIG. 1) 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:v (0.005≦v≦0.05). TM:MgMix1=1:v (0.007≦v≦0.04) is more preferable. TM:MgMix1=1:0.02 is more preferable.

[0036] 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.

[0037] The mixed materials are collected (step S32 in FIG. 1) to obtain a mixture 903 (step S32 in FIG. 1). Step S33).

[0038] Next, the mixture 903 is heated (step S34 in FIG. 1). LiMO2 is generated by annealing. Therefore, the temperature, time, and atmosphere The conditions under which step S34 is performed, such as the temperature, the weight of the mixture 903 to be annealed, etc., are important. In this specification, annealing refers to heating the mixture 903 or at least the mixture 903. This also includes heating a heating furnace equipped with a heater.

[0039] If the conditions in S34 are not appropriate, a positive electrode active material with good properties may not be obtained. In addition, the processing time of step S34 is often longer than that of other steps. By shortening the processing time, it becomes possible to prepare the positive electrode active material in a short time. Therefore, a technique for shortening the processing time of step S34 is required.

[0040] Here, the inventors of the present invention use the fluoride (LiF in this embodiment) contained in the mixture 903 as By performing annealing in an atmosphere containing It has also been found that an embodiment of the present invention allows the annealing time to be shortened.

[0041] [Effect of annealing in a fluoride-containing atmosphere] The annealing temperature is preferably equal to or higher than the temperature at which the mixture 902 melts. It is assumed that the mixture 902 melts when annealed. For example, MgF2 (melting point 126 The mixture of LiF (melting point 848°C) and LiF (melting point 848°C) melts and is distributed on the surface of the composite oxide particles. It is thought that the melting of MgF2 promotes the reaction with LiCoO2, resulting in the formation of LiMO It is believed that 2 is produced. Therefore, the fluoride and the magnesium source form a eutectic mixture. A combination is preferred.

[0042] The annealing temperature is preferably equal to or higher than the temperature at which the mixture 903 melts. (e.g., LiF), a magnesium source (e.g., MgF2) and a lithium oxide (e.g., Li CoO2) forms a covalent mixture, which is thought to promote the formation of LiMO2. .

[0043] In addition, the annealing temperature must be below the decomposition temperature of LiCoO2 (1130°C). Therefore, it is necessary to heat the fluoride at a temperature above the eutectic point of the fluoride and magnesium source, but below 1130°C. is preferred.

[0044] As will be described later, the eutectic point of LiF and MgF2 is around 735°C. gF2 and LiCoO2 show an endothermic peak at around 820℃ by differential scanning calorimetry (DSC measurement). Therefore, the annealing temperature is preferably 735°C or higher, and 820°C or higher. The decomposition temperature of LiCoO2 is 1130°C, but At this temperature, there is a concern that LiCoO2 may decompose, even if only slightly. The temperature is preferably 1130°C or lower, and more preferably 1000°C or lower.

[0045] Therefore, the annealing temperature is preferably 735°C or higher and 1130°C or lower. The temperature is preferably 820°C or higher and 1130°C or lower. °C or higher and 1000 °C or lower is more preferable.

[0046] Here, we will explain the DSC measurement of a mixture of LiF and MgF2.

[0047] The measurement device used is ThermoplusEV02 manufactured by Rigaku Co., Ltd. The temperature range is 25 The temperature is increased from 1000°C to 1000°C at a rate of 20°C / min.

[0048] Figure 2 shows the DSC measurement results for a mixture of LiF and MgF2 (LiF / MgF2 = 0.33 mol%). The measurement results are shown in Figure 2. An endothermic peak is observed around 735°C. The mixture of these two has a eutectic point around 735°C.

[0049] In this embodiment, LiF, which is a fluoride, is thought to function as a flux. Therefore, when LiF evaporates and the amount of LiF in the mixture 903 decreases, MgF2 melts. It is expected that the formation of LiMO2 will be suppressed. It is preferable to heat the mixture while suppressing the polymerization.

[0050] Therefore, the mixture 903 is heated in an atmosphere containing LiF, that is, the Li By heating the mixture 903 under high F partial pressure, the amount of LiF in the mixture 903 This suppresses vaporization and allows the efficient production of LiMO2. A good positive electrode active material can be produced, and the annealing time can also be shortened.

[0051] Here, a mixture of LiF and MgF2 (LiF / MgF2 = 0.33 mol%) was added to the specified The weight loss rate when heated at a temperature can be investigated experimentally. The MgF2 mixture is heated to a predetermined temperature at 200°C / h and maintained at that temperature for 10 hours. After that, the temperature is lowered over 10 hours. Oxygen is supplied at a flow rate of 2.5 L / min. The results of the weight loss rate measurement are shown in Table 1. The weight loss rate (%) was calculated by dividing the weight of the mixture by the weight of the mixture before heating and multiplying it by 100. )

[0052] [Table 1]

[0053] As shown in Table 1, the mixture of LiF and MgF2 shows a confirmed weight loss at least at 700°C. Therefore, at least at temperatures above 700°C, the components of LiF and MgF2 It can be seen that it is evaporated and lost from the reaction system.

[0054] In this specification, a heating furnace is a furnace used to heat treat (anneal) a substance or mixture. The heater and the equipment are designed to withstand an atmosphere containing fluoride and temperatures of at least 600°C. The heating furnace has an inner wall. The heating furnace has at least one of the functions of reducing pressure and increasing pressure inside the heating furnace. A pump having the above structure may be provided.

[0055] [Annealing in a fluoride-containing atmosphere] An example of a method for annealing in a heating furnace with an atmosphere containing fluoride is shown in FIGS. 3A and 3B. and explain.

[0056] The heating furnace 120 shown in FIG. 3A and FIG. 3B includes a heating furnace space 102, a heating plate 104, a heater unit 105, and a heater element 106. 3A shows a container 116 containing a mixture 903 placed in a heating furnace. The figure shows the state in which the mixture 903 is placed in the space 102. The mixture 903 contains fluoride. The mixture 903 is heated to vaporize a portion of the fluoride contained in the mixture 903. The mixture 903 can be heated in an atmosphere containing a fluoride.

[0057] Here, the valence of Co (cobalt) in LiMO2 produced according to one embodiment of the present invention is 3 Co can be divalent or trivalent. Therefore, the reduction of Co is suppressed. In order to achieve this, the atmosphere in the heating furnace space 102 preferably contains oxygen. It is more preferable that the ratio of oxygen to nitrogen in the atmosphere is equal to or greater than that of the air atmosphere. It is more preferable that the oxygen concentration in the atmosphere of O2 is equal to or higher than that of the air atmosphere. It is necessary to introduce an oxygen-containing atmosphere into the furnace space.

[0058] In order to introduce an atmosphere containing oxygen into the space 102 inside the heating furnace, oxygen gas is supplied from the outside. However, the molecular weight of oxygen (O2) is about 32, and the molecular weight of fluorine is about 1000. The molecular weight of lithium fluoride (LiF) is about 26, so gaseous LiF is Therefore, when annealing is performed in a flow of oxygen gas, the Li vaporized by heating F is easily discharged to the outside of the heating furnace space 102, and annealing is performed in a LiF atmosphere. It may not be possible.

[0059] Therefore, in one embodiment of the present invention, as shown in FIGS. 3A and 3B, the anode is heated in an atmosphere containing fluoride. To perform the anneal, oxygen gas is not flowed or a lid 118 is placed on the container 116. Annealing is performed under either or both of the conditions.

[0060] In order to perform annealing without flowing oxygen gas, the space 102 inside the heating furnace is and a step of placing the container 116 containing the mixture 903 in the space 10 inside the heating furnace. 2. By performing the steps in this order, the mixture 903 is During annealing, the space 102 inside the heating furnace is sealed. Close the enclosure to prevent gas from being transported outside.

[0061] Alternatively, as shown in FIG. 3B, the container 116 is covered with a lid 118 and annealed. By this, the space 119 closed by the container 116 and the lid 118 is filled with an atmosphere containing fluoride. Since the volume of the space 119 is smaller than that of the space 102 in the heating furnace, By vaporizing a certain amount of fluoride, an atmosphere containing fluoride can be obtained. The reaction system can be converted into a fluoride-containing atmosphere without significantly reducing the amount of fluoride contained in the mixture 903. Therefore, LiMO2 can be produced efficiently. In addition, by using the lid 118, the mixture 903 can be easily and inexpensively heated in an atmosphere containing fluoride. can be annealed.

[0062] By providing the lid 118, it is possible to create an atmosphere containing a sufficient amount of fluoride without sealing the space 102 inside the heating furnace. Therefore, when the lid 118 is provided, oxygen gas is supplied to the annealing chamber. The deep features shown in Figures 3A and 3B can be easily annealed. Preferably, the container 116a is provided with a lid 118. The deep container 116a is a shallow container. When the mixture 903 is poured to the same depth as in the container 116, the space Therefore, it is difficult to maintain an atmosphere containing a sufficient amount of fluoride. can.

[0063] It is more preferable to perform annealing without flowing oxygen gas and with the lid 118 in place.

[0064] 4A and 4B show detailed steps in the case where oxygen gas is not flowed in step S34 shown in FIG. The step of creating an oxygen-containing atmosphere in the space 102 inside the heating furnace (the steps in FIGS. 4A and 4B) Step S34-1) and step S34-2) of placing the container 116 containing the mixture 903 in the space 102 inside the heating furnace. There is no particular limitation on the order of the steps (step S34-2 in FIGS. 4A and 4B). As shown in the figure, after the container 116 containing the mixture 903 is placed in the space 102 inside the heating furnace, A step of creating an atmosphere containing oxygen in the inner space 102 may be carried out. Thereafter, a step of heating the heating furnace 120 (S34-3 in FIGS. 4A and 4B) is performed.

[0065] There is no particular limitation on the method for creating an oxygen-containing atmosphere in the space 102 inside the heating furnace. After evacuating the furnace space 102, oxygen gas or dry air containing oxygen is introduced. Examples include a method of injecting oxygen gas or a gas containing oxygen, such as dry air, for a certain period of time. It is preferable to evacuate the space 102 inside the heating furnace and then introduce oxygen gas (oxygen substitution). The air may be an atmosphere containing oxygen.

[0066] As a step of placing the container 116 containing the mixture 903 in the space 102 inside the heating furnace, Although there is no specific method, for example, the container 116 may be directly placed in the space 102 inside the heating furnace, or the container 116 may be placed in the space 102 inside the heating furnace as shown in FIG. As shown in the figure, a device having a transport mechanism is used, and the container 116 is transported into the heating furnace by the transport mechanism. One method is to install it in the space 102.

[0067] There is no particular limitation on the process for heating the heating furnace 120. The heating can be performed using a mechanism.

[0068] There is no particular limitation on how the mixture 903 is arranged when placed in the container 116. 3B, the mixture 903 is placed in a container 116 so that the top surface of the mixture 903 is flat against the bottom surface of the container 116. In other words, it is preferable to arrange the mixture 903 so that the height of the upper surface of the mixture 903 is uniform. I wish.

[0069] The annealing is preferably carried out at an appropriate temperature and for an appropriate time. is the particle size of the composite oxide having lithium, a transition metal, and oxygen in step S25. The temperature varies depending on the conditions such as the size and composition of the particles. Small particles can be heated to a lower temperature than large particles. A longer or shorter time may be more preferable.

[0070] For example, if the average particle diameter (D50) of the particles in step S25 is about 12 μm, annealing The time is preferably, for example, 3 hours or more, more preferably 10 hours or more.

[0071] On the other hand, if the average particle diameter (D50) of the particles in step S25 is about 5 μm, The time is preferably, for example, from 1 hour to 10 hours, and more preferably about 2 hours.

[0072] The temperature drop time after annealing is preferably, for example, 10 hours or more and 50 hours or less.

[0073] The annealed material is collected (step S35 in FIG. 1) to obtain a positive electrode active material 904. (Step S36 in Figure 1).

[0074] An example of a heating furnace is shown in Figure 5. In Figure 5, the parts with the same functions as those in Figure 3 are marked with the same symbols. The hatch patterns are the same and the symbols may be omitted. The same reference numerals are used to denote the same parts, and detailed explanations thereof may be omitted.

[0075] <Heating furnace configuration> The heating furnace used in one embodiment of the present invention is not particularly limited, and various types of heating furnaces, such as batch type and continuous type, can be used. A heating furnace can be used, an example of which is shown in Figures 5A and 5B.

[0076] The heating furnace 130 shown in Figure 5A is an example of a continuous heating furnace. A container 134 containing a mixture 903 is placed on the belt conveyor 132, and By performing the treatment in the thermal furnace 130, continuous annealing can be performed. The annealing time can be adjusted by adjusting the conveyor movement speed. Fluoride 906 is placed in one of the containers 134 and annealed simultaneously with mixture 903. Therefore, the space 102 in the heating furnace can be made into a fluoride atmosphere. Then, it is preferable to cover the container 134. The mixture 903 is annealed in the heating furnace 130. In this way, positive electrode active material 904 can be obtained.

[0077] The heating furnace 140 shown in FIG. 5B is an example of a rotary heating furnace. 2, an atmosphere control section 144, and a recovery section 146. The mixture 903 is poured into the heating plate 104. The heating plate 104 has a mechanism for rotating. The flow path is inclined toward the collection section 146. By adopting this configuration, the mixture 903 flows By adjusting the tilt and rotation speed, annealing can be performed. The cooling time can be adjusted. The annealed mixture 903 is collected in the collection section 146. Positive electrode active material 904 can be obtained.

[0078] The atmosphere control unit 144 controls the oxygen atmosphere and the fluoride atmosphere in the heating furnace space 102. can be adjusted.

[0079] This embodiment mode can be implemented in appropriate combination with other embodiment modes.

[0080] (Embodiment 2) An example of a method for producing LiMO2 will be explained below. The fabrication method when multiple metal elements are used is explained using Figure 6. Reveal.

[0081] <<Positive electrode active material production method 2>> Figure 6 shows the process for producing LiMO2 composite oxide containing Mg, Ni, and Al in addition to Co. This is an example of the production method. Each metal element source other than Li and Co is mixed and crushed separately. Then, the finely pulverized metal element sources were mixed with lithium cobalt oxide and annealed. Steps S11 to S36 are the same as those described in the first embodiment and FIG. That is, in the step S34, the mixture 903-2 is annealed in an atmosphere containing LiF. This is preferable. Positive electrode active material 904-2 is obtained by the manufacturing process shown in FIG.

[0082] <Steps S15, S16, and S17> In addition, finely pulverized 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).

[0083] <Steps S18, S19, and S20> In addition, finely divided 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).

[0084] In the above steps S15 to S20, nickel hydroxide is used as a nickel (Ni) source. Aluminum hydroxide was used as the aluminum (Al) source, but the nickel source and aluminum The ammonium source is not limited to these. Oxides and halides containing each element can also be used. do.

[0085] <<Positive electrode active material production method 3>> Figure 7 shows the preparation of a composite oxide containing Mg, Ni, and Al in addition to Co as LiMO2. This is an example of a manufacturing method. The metal element sources other than Li and Co are simultaneously mixed (S21 ), and after grinding, mix with lithium cobalt oxide and anneal. S35 is the same as the step described in the first embodiment and FIG. It is preferable to anneal the mixture 903-3 in an atmosphere containing LiF. The positive electrode active material 904-3 is obtained by this manufacturing process.

[0086] <Steps S22 to S24> Similar to steps S15 to S17 and steps S18 to S20 described above Prepare finely powdered MgF2, Ni(OH)2, and Al(OH)3. Aluminum hydroxide is recovered in step S22 by mixing aluminum hydroxide with acetone in advance. Step S23 is performed to obtain the pulverized mixture 902- 3 is obtained (step S24).

[0087] <<Method 4 for preparing positive electrode active material>> Figure 8 shows the preparation of a composite oxide containing Mg, Ni, and Al in addition to Co as LiMO2. This is an example of a manufacturing process. This manufacturing method produces a composite oxide represented by LiMO2 containing Mg. Then, a Ni source and an Al source are added to prepare a composite oxide containing Mg, Ni, and Al. S11 to S14 and S31 to S36 are the steps described in the first embodiment and FIG. That is, in the step S34, the mixture 903 is annealed in an atmosphere containing LiF. It is preferable to perform the steps S15 to S17 described with reference to FIG. Positive electrode active material 904-4 is obtained by the manufacturing process shown in FIG.

[0088] As shown in step S50, the positive electrode active material 904 and finely powdered nickel hydroxide are mixed together. Then, the mixed material is collected (step S51). To do this, step S15 of mixing nickel hydroxide and acetone and step S16 of recovering the nickel hydroxide are performed. In step S16, finely divided nickel hydroxide is obtained (step S1 7).

[0089] The materials mixed in step S50 are collected in step S51 to obtain a mixture 908 (see FIG. 8). Step S52).

[0090] Next, through steps S53 to S55, Al is added. For example, liquid phase methods such as the sol-gel method, solid phase methods, sputtering methods, vapor deposition methods, CVD (chemical vapor deposition) Chemical Vapor Deposition (CVD) and Pulsed Laser Deposition (PLD) methods can be applied. do.

[0091] As shown in FIG. 8, first, in step S52, a metal source is prepared. When the sol-gel method is applied, a solvent to be used in the sol-gel method is prepared. Lithium cobalt oxide, Al hydroxide, Al oxide, etc. can be used. The number of cobalt atoms contained in the metal source is 1, and the concentration of aluminum contained in the metal source is 0.001 times or more. The upper limit should be 0.02 times or less.

[0092] As an example, a sol-gel method is used, and aluminum isopropoxide is used as a metal source. An example using 2-propanol as the solvent is shown below.

[0093] Next, aluminum alkoxide was dissolved in 2-propanol, and the mixture was are mixed (step S53 in FIG. 8).

[0094] 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 concentration in the isopropoxide is 0.001 to 0.02 times. It is preferable to add

[0095] Next, the mixture of the alcohol solution of metal alkoxide and the lithium cobalt oxide particles was added to water. The mixture is stirred in an atmosphere containing HCl. Stirring can be performed, for example, with a magnetic stirrer. The stirring time is determined based on the time at which the water in the atmosphere and the metal alkoxide undergo hydrolysis and polycondensation reactions. Any time sufficient for this is sufficient, for example, 4 hours, 25°C, 90% RH (relative humidity). Humidity (relative humidity) conditions. In an atmosphere where the temperature is not controlled, such as in a draft chamber, In such a case, it is preferable to carry out the stirring for a longer period of time, e.g. For example, it may be left at room temperature for 12 hours or more.

[0096] By reacting atmospheric moisture with metal alkoxide, the The sol-gel reaction can proceed slowly. Also, the reaction between metal alkoxide and water at room temperature can be This allows for a gentler reaction than, for example, heating at a temperature above the boiling point of the alcohol solvent. By proceeding with the sol-gel reaction slowly, A coating layer of uniform thickness and high quality can be formed.

[0097] After the above treatment, the precipitate is collected from the mixed solution (step S54 in FIG. 8). 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).

[0098] Next, the collected residue is dried to obtain a mixture 909 (Step S55 in FIG. 8). The drying process may be, for example, vacuum or forced air drying at 80° C. for 1 hour to 4 hours.

[0099] Next, the resulting mixture is heated (Step S56 in FIG. 8).

[0100] The heating time is preferably 1 hour or more and 80 hours or less within the heating temperature range. I wish.

[0101] 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.

[0102] The heating is preferably carried out in an atmosphere containing oxygen.

[0103] 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.

[0104] The heating temperature in step S56 is lower than the heating temperature in step S34. preferable.

[0105] <Steps S57 and S58> Next, the cooled particles are collected (step S57 in FIG. 8). By the above steps, the positive electrode active material 904-4 can be produced ( Step S58 in FIG. 8).

[0106] This embodiment mode can be implemented in appropriate combination with other embodiment modes.

[0107] (Embodiment 3) In this embodiment, one structure of a positive electrode active material manufactured by a manufacturing method according to one embodiment of the present invention will be described. An example will be described.

[0108] [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 Mg Examples include:

[0109] 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.

[0110] 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.

[0111] The positive electrode active material will be described with reference to Figs. 9 and 10. The case where cobalt is used as the transition metal contained in the electrode active material will be described.

[0112] The positive electrode active material produced in one embodiment of the present invention has a high resistance to CoO This can reduce the displacement between the two layers and also reduce the change in volume. Therefore, the compound can achieve excellent cycle characteristics. Also, the compound can have a stable crystal structure in a high-voltage charged state. Therefore, when the compound is in a high-voltage charged state, short circuits may be less likely to occur. In such cases, since safety is further improved, it is preferable. In particular, a compound represented by the chemical formula Li (1-x-y) Co (1-a-b ) Ni (x+a) Mg (y+b) O2 has good characteristics when 0 < x + a ≤ 0.015 and 0 < y + b ≤ 0.06, so it is preferable.

[0113] In this compound, the change in crystal structure between the fully discharged state and the state charged at a high voltage, and the volume difference when compared per the same number of transition metal atoms are small.

[0114] The crystal structure of the positive electrode active material 904 before and after charge and discharge is shown in FIG. 9. The positive electrode active material 904 is a composite oxide having lithium, cobalt, and oxygen. In addition to the above, it is preferable to have magnesium. Also, it is preferable to have a halogen such as fluorine or chlorine. Also, it is preferable to have aluminum and nickel.

[0115] The crystal structure at a charge depth of 0 (discharged state) in FIG. 9 is the same R-3m (O3) as in FIG. 10. On the other hand, when the positive electrode active material 904 is at a fully charged charge depth, it has a crystal with a structure different from the H1-3 type crystal structure. This structure has a space group of R-3m. Although it is not a spinel-type crystal structure, ions such as cobalt and magnesium occupy the oxygen six-coordination positions, and the arrangement of cations has symmetry similar to that of the spinel type. Therefore, in this specification, etc., this structure is referred to as a pseudo-spinel type In the diagram of the pseudospinel crystal structure shown in Figure 9, cobalt In order to explain the symmetry of the atom and the symmetry of the oxygen atom, the lithium is omitted. However, in reality, lithium exists between the CoO2 layers at a ratio of, for example, 20 atomic % or less relative to cobalt. In addition, in both the O3 type crystal structure and the pseudospinel type crystal structure, CoO2 It is preferable that magnesium exists dilutely between the layers, i.e., at the lithium site. A halogen such as fluorine may be present randomly and dilutely at the oxygen site.

[0116] 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.

[0117] 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.

[0118] 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.

[0119] In the positive electrode active material 904, when a large amount of lithium is released by charging at a high voltage, the crystal structure The change is more suppressed than in the positive electrode active material 100C described later. As can be seen, there is almost no misalignment of the CoO2 layers in these crystal structures.

[0120] More specifically, the positive electrode active material 904 has a stable structure even when the charging voltage is high. For example, the charge voltage at which the positive electrode active material 100C becomes an H1-3 type crystal structure, e.g. For example, the R-3m(O3) result is observed even at a voltage of about 4.6 V based on the potential of lithium metal. There is a region of charging voltage where the crystal structure can be maintained, and there is a region where the charging voltage is further increased, for example, The pseudospinel type is also observed at a voltage of about 4.65V to 4.7V relative to the potential of aluminum metal. If the charging voltage is further increased, the H1-3 type crystal structure can be obtained. In secondary batteries, for example, when graphite is used as the negative electrode active material, crystals may be observed. If the voltage of the secondary battery is between 4.3V and 4.5V, for example, R-3m( There is a region of charging voltage where the crystal structure of O3 can be maintained, and there is a region where the charging voltage is further increased. For example, the pseudo-spin potential is between 4.35V and 4.55V based on the potential of lithium metal. There is a region where a crystalline structure of the crystalline form can be formed.

[0121] Therefore, the crystal structure of the positive electrode active material 904 does not collapse even when it is repeatedly charged and discharged at a high voltage. It is difficult to get rid of.

[0122] 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.

[0123] 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. In order to achieve this, it is preferable to perform a heat treatment in the process of producing the positive electrode active material 100A-1. stomach.

[0124] 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.

[0125] 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.

[0126] 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 positive electrode active material prepared according to one embodiment of the present invention also becomes incorporated into the The number of magnesium atoms is between 0.001 and 0.1 times the number of cobalt atoms. It is preferable that the ratio is more than 0.01 times and less than 0.04 times, and more preferable that the ratio is about 0.02 times. The magnesium concentration shown here is preferably determined by measuring the concentration of the positive electrode active material using, for example, ICP-MS or the like. The value may be obtained by elemental analysis of the entire particle of the positive electrode active material, or may be obtained by the elemental analysis of the entire particle of the positive electrode active material during the manufacturing process. It may be based on the value of the raw material composition.

[0127] The number of nickel atoms in the positive electrode active material 904 is preferably 7.5% or less of the number of cobalt atoms. The content is preferably 0.05% or more and 4% or less, and more preferably 0.1% or more and 2% or less. The nickel concentration indicated by is determined by, for example, measuring the elemental composition of the entire particle of the positive electrode active material using ICP-MS or the like. It may be a value obtained by performing an analysis, or may be a value based on the blending of raw materials in the process of producing the positive electrode active material. It's fine.

[0128] ≪Particle size≫ If the particle size of the positive electrode active material 904 is too large, it becomes difficult for lithium to diffuse. On the other hand, if the size is too small, the surface of the active material layer becomes too rough. Problems include difficulty in supporting the active material layer when coating on the body, and excessive reaction with the electrolyte. Therefore, the average particle size (D50: also called the median size) is 1 μm or more. Preferably, the thickness is 0.00 μm or less, more preferably 2 μm to 40 μm, and more preferably 5 μm or less. More preferably, it is at most 30 μm.

[0129] <Analysis method> Whether a certain positive electrode active material exhibits a pseudospinel crystal structure when charged at a high voltage can be determined by The positive electrode charged at high voltage was analyzed by XRD, electron diffraction, neutron diffraction, and electron spin resonance (ES This can be determined by analyzing the positive electrode using XRD, nuclear magnetic resonance (NMR), etc. High crystallinity and high resolution analysis of the symmetry of transition metals such as cobalt in the active material It is possible to compare the orientation of the crystals and analyze the periodic distortion of the lattice and the crystallite size. This method is preferred in that sufficient accuracy can be obtained even if the positive electrode obtained by disassembling the secondary battery is measured as it is. It's nice.

[0130] As described above, the positive electrode active material 904 has a crystal structure that changes depending on whether it is charged at a high voltage or discharged. The characteristic of this battery is that there is little change in structure between the high voltage charged state and the discharged state. Materials with a crystalline structure of 50 wt% or more are not preferred because they cannot withstand high voltage charging and discharging. Furthermore, there are cases where the desired crystal structure cannot be achieved simply by adding impurity elements. For example, lithium cobalt oxide with magnesium and fluorine, Although they have in common the point that the pseudo-spinel crystal structure is 60 wt% when charged at high voltage, or more, or the H1-3 type crystal structure accounts for 50 wt% or more. At a predetermined voltage, the pseudo-spinel crystal structure becomes almost 100 wt %. Increasing the voltage may result in the formation of an H1-3 type crystal structure. It is preferable to analyze the crystal structure by XRD or the like.

[0131] 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 should be stored in an inert atmosphere such as an argon-containing atmosphere. It is preferable to handle it with care.

[0132] <Comparative Example Positive Electrode Active Material 100C> The positive electrode active material 100C shown in FIG. 10 is a material containing halogen and magnesium by a manufacturing method described later. The cobalt oxide shown in Figure 10 is lithium cobalt oxide (LiCoO2) with no added zinc. As described in Non-Patent Documents 1 and 2, lithium has a charge depth of 1000 volts. The crystal structure changes.

[0133] As shown in FIG. 10, 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 an octahedral structure in which oxygen atoms are six-coordinated to each other is connected on a plane in an edge-sharing state. do.

[0134] 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.

[0135] 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 of the other structures. In this specification, the c-axis of the H1-3 type crystal structure is expressed as 0 for ease of comparison with other structures. It will be shown as a diagram of half of a unit cell.

[0136] 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.

[0137] 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.

[0138] However, these two crystal structures have a large misalignment of the CoO2 layers. As shown by the arrows, in the H1-3 type crystal structure, the CoO2 layer is Such dynamic structural changes have a negative effect on the stability of the crystal structure. Can be given.

[0139] 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%.

[0140] 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.

[0141] 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.

[0142] This embodiment mode can be implemented in appropriate combination with other embodiment modes.

[0143] (Fourth embodiment) In this embodiment, a secondary battery including a positive electrode active material manufactured by a manufacturing method according to one embodiment of the present invention will be described. Examples of materials that can be used in the battery will be described. The following description will be given taking as an example a secondary battery in which the battery and electrolyte are enclosed in an exterior body.

[0144] [Positive electrode] The positive electrode has a positive electrode active material layer and a positive electrode current collector.

[0145] <Cathode active material layer> The positive electrode active material layer contains positive electrode active material particles. The positive electrode active material layer also contains a conductive additive and a biomaterial. The sensor may have a fin.

[0146] The positive electrode active material particles are made of a positive electrode active material produced by the production method of one embodiment of the present invention. You can be there.

[0147] As the conductive additive, a carbon material, a metal material, a conductive ceramic material, or the like can be used. A fibrous material may also be used as the conductive additive. The content of the electrical auxiliary agent is preferably 1 wt% or more and 10 wt% or less, and more preferably 1 wt% or more and 5 wt% or less. is more preferred.

[0148] The conductive additive can form an electrically conductive network in the electrode. This allows the electrical conduction path between the positive electrode active materials to be maintained. By adding the agent, an active material layer having high electrical conductivity can be realized.

[0149] Examples of the conductive additive include natural graphite, artificial graphite such as mesocarbon microbeads, and carbon fiber. Examples of carbon fibers that can be used include mesophase pitch carbon fibers. Carbon fibers such as isotropic pitch-based carbon fibers can be used. Carbon nanofibers and carbon nanotubes can be used. The tube can be produced by, for example, vapor phase growth method. For example, carbon black (acetylene black (AB) etc.), graphite particles Carbon materials such as graphene and fullerene can be used. Metal powders and fibers such as nickel, aluminum, silver, and gold, as well as conductive ceramic materials, etc. It can be used.

[0150] A graphene compound may also be used as the conductive additive.

[0151] Graphene compounds have excellent electrical properties, such as high conductivity, as well as high flexibility and high In addition, graphene may have excellent physical properties such as high mechanical strength. The graphene compound has a planar shape, which allows for surface contact with low contact resistance. In addition, even if they are thin, they can have very high conductivity, and even a small amount can be used to efficiently conduct electricity within the active material layer. Therefore, the graphene compound can be used as a conductive additive. This is preferable because it is possible to increase the contact area between the active material and the conductive additive. This is preferable because it may be possible to reduce the electrical resistance. For example, graphene, multi-graphene, or reduced graphene O It is particularly preferred to use RGO oxide. This refers to a compound obtained by reducing graphene (GO: Graphene Oxide).

[0152] When using active material particles with a small particle size, for example, active material particles with a particle size of 1 μm or less, The specific surface area of ​​the active material particles is large, and therefore more conductive paths are required to connect the active material particles together. In such cases, graphene compounds that can efficiently form conductive paths even in small amounts are used. It is particularly preferred to use

[0153] As an example, in the case where a graphene compound is used as a conductive additive in the active material layer 200, An example of the cross-sectional structure will be described.

[0154] 11A shows a vertical cross-sectional view of the active material layer 200. FIG. 11B shows the area surrounded by the dotted line in FIG. 11A. The active material layer 200 is made of granular positive electrode active material 101 and a conductive additive The graphene compound 201 includes a binder (not shown). For example, graphene or multi-graphene may be used as the compound 201. The graphene compound 201 preferably has a sheet shape. The object 201 is a multi-graphene or (and) a plurality of graphenes partially overlapping each other. It may be in the form of a sheet.

[0155] In the vertical cross section of the active material layer 200, as shown in FIG. 11A, In FIG. 11A, the sheet-like graphene compound 201 is dispersed almost uniformly. The phene compound 201 is shown in bold as a schematic diagram, but in reality it is a single or multilayer structure of carbon molecules. The plurality of graphene compounds 201 are thin films having a thickness. 101, or is attached to the surface of a plurality of granular positive electrode active materials 101. Since they are formed to be attached to each other, they are in surface contact with each other.

[0156] Here, a plurality of graphene compounds are bonded to each other to form a mesh-like graphene compound. It is possible to form a graphene sheet (hereinafter referred to as a graphene compound net or graphene net). When the active material is covered with a graphene net, the graphene net can connect the active material to each other. It can also function as a binder to bind the particles together. Since it is possible to reduce the ratio of active material to the electrode volume or weight, or it is not necessary to use In other words, the capacity of the power storage device can be increased.

[0157] 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 layer 200, it is preferable to reduce it. By using graphene oxide, which has extremely high dispersibility in polar solvents, The mixture 201 can be dispersed approximately uniformly inside the active material layer 200. The solvent is removed from the dispersion medium containing the dispersed graphene oxide, and the graphene oxide is reduced. Therefore, the graphene compounds 201 remaining in the active material layer 200 are partially overlapped with each other. By dispersing the particles so that they are in surface contact, a three-dimensional conductive path can be formed. The reduction of graphene oxide may be carried out, for example, by heat treatment or by using a reducing agent. Good too.

[0158] Therefore, unlike granular conductive additives such as acetylene black, which come into point contact with the active material, graphite Since the compound 201 enables surface contact with low contact resistance, it is more effective than ordinary conductive additives. The amount of the granular positive electrode active material 101 and the graphene compound 201 is small, and the electrical conductivity between the granular positive electrode active material 101 and the graphene compound 201 is improved. Therefore, the ratio of the positive electrode active material 101 in the active material layer 200 can be increased. This makes it possible to increase the discharge capacity of the power storage device.

[0159] Examples of binders include styrene-butadiene rubber (SBR) and styrene-isoprene. Acrylonitrile-styrene rubber, acrylonitrile-butadiene rubber, butadiene rubber, ethylene-propylene It is preferable to use a rubber material such as a propylene-diene copolymer. Fluorine rubber can be used.

[0160] 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), methyl cellulose, ethyl cellulose, hydroxypropyl cellulose Cellulose derivatives such as cellulose, diacetyl cellulose, and regenerated cellulose, as well as starch These water-soluble polymers can be used in combination with the rubber materials described above. It is even better if there is one.

[0161] Alternatively, the binder may be polystyrene, polymethyl acrylate, or polymethyl methacrylate. Polymethylmethacrylate (PMMA), sodium polyacrylate, polyvinyl alcohol (PVA), poly Ethylene oxide (PEO), polypropylene oxide, polyimide, polyvinyl chloride, Polytetrafluoroethylene, polyethylene, polypropylene, polyisobutylene, poly Ethylene terephthalate, nylon, polyvinylidene fluoride (PVDF), polyacrylo Nitrile (PAN), Ethylene Propylene Diene Polymer, Polyvinyl Acetate, Nitrocel It is preferable to use a material such as loin.

[0162] The binder may be used in combination with two or more of the above.

[0163] 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 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 carbohydrates. Carboxymethylcellulose (CMC), methylcellulose, ethylcellulose, hydroxy Cellulose derivatives such as propyl cellulose, diacetyl cellulose, and regenerated cellulose Carbohydrates and starches can be used.

[0164] The cellulose derivatives such as carboxymethyl cellulose are, for example, By converting cellulose into salts such as sodium salts or ammonium salts, the solubility increases, It is easier to exert its effect as a viscosity adjuster. The increased solubility makes it easier to make electrode slurry. When preparing a substrate, it is also possible to improve the dispersibility of the active material and other components. In this case, the cellulose and cellulose derivatives used as binders for electrodes include These salts are also included.

[0165] Water-soluble polymers stabilize viscosity by dissolving in water, and also act as active materials and binders. Other materials to be combined, such as styrene butadiene rubber, are stably dispersed in aqueous solution. In addition, since it has functional groups, it can be easily and stably adsorbed onto the surface of the active material. It is expected that cellulose derivatives such as carboxymethyl cellulose will For example, 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.

[0166] 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 play a role in suppressing the decomposition of the electrolyte. It is a film with no electrical conductivity or extremely low electrical conductivity, and is When a dynamic membrane 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 while allowing lithium ions to conduct. And even more desirable.

[0167] <Positive electrode current collector> The positive electrode current collector may be made of metals such as stainless steel, gold, platinum, aluminum, titanium, or the like. Highly conductive materials such as alloys of these 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.

[0168] [Negative electrode] The negative electrode has a negative electrode active material layer and a negative electrode current collector. The negative electrode active material layer contains a conductive additive and and a binder.

[0169] <Negative electrode active material> As the negative electrode active material, for example, an alloy-based material or a carbon-based material can be used.

[0170] As a negative electrode active material, it is possible to carry out charge-discharge reactions by alloying and dealloying reactions with lithium. Any suitable element can be used, such as silicon, tin, gallium, aluminum, Rumanium, lead, antimony, bismuth, silver, zinc, cadmium, indium, etc. Materials containing at least one of these elements can be used. These elements have a large capacity compared to carbon. Silicon has a particularly high theoretical capacity of 4200mAh / g. It is preferable to use silicon. Alternatively, compounds containing these elements may be used. For example, SiO, Mg2Si, Mg2Ge, SnO, SnO2, Mg2Sn, SnS2, V 2Sn3, FeSn2, CoSn2, Ni3Sn2, Cu6Sn5, Ag3Sn, Ag3 Sb, Ni2MnSb, CeSb3, LaSn3, La3Co2Sn7, CoSb3, I nSb, SbSn, etc. Here, the charge / discharge reaction occurs due to alloying and dealloying reactions with lithium. Elements capable of undergoing a reaction and compounds containing such elements are sometimes called alloy materials. do.

[0171] In this specification and the like, SiO refers to, for example, silicon monoxide. Alternatively, SiO refers to SiO x Here, x preferably has a value of 1 or close to 1. For example, x is preferably 0.2 or more and 1.5 or less, and more preferably 0.3 or more and 1.2 or less.

[0172] Carbon materials include graphite, easily graphitizable carbon (soft carbon), and non-graphitizable carbon (hard carbon). carbon nanotubes, graphene, carbon black, etc. may be used. .

[0173] Examples of graphite include artificial graphite and natural graphite. Examples include carbon microbeads (MCMB), coke-based artificial graphite, and pitch-based artificial graphite. Here, as the artificial graphite, spherical graphite having a spherical shape can be used. For example, the MCMB may have a spherical shape, which is preferable. It is relatively easy to reduce the particle size, which is sometimes preferable. Examples include flake graphite and spherical natural graphite.

[0174] When lithium ions are inserted into graphite (when lithium-graphite intercalation compounds are formed), It exhibits a low potential similar to that of lithium metal (0.05V to 0.3V vs. Li / L i + This allows the lithium-ion secondary battery to exhibit a high operating voltage. In addition, 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.

[0175] In addition, titanium dioxide (TiO2) and lithium titanium oxide (Li4T i5O 12 ), lithium-graphite intercalation compound (Li x C6), niobium pentoxide (Nb2O5) Oxides such as tungsten oxide (WO2) and molybdenum oxide (MoO2) can be used. can.

[0176] In addition, the negative electrode active material is a composite nitride of lithium and transition metals, which has a Li3N structure. Li 3-x M x N (M=Co, Ni, Cu) can be used. For example, Li 2.6 Co 0.4 N3 has a large charge / discharge capacity (900mAh / g, 1890mAh / cm 3 ) And preferable.

[0177] When a composite nitride of lithium and a transition metal is used, the negative electrode active material contains lithium ions, The positive electrode active material is a combination of materials such as V2O5 and Cr3O8 that do not contain lithium ions. It is preferable that a material containing lithium ions is used as the positive electrode active material. By first removing the lithium ions contained in the positive electrode active material, A complex nitride of lithium and a transition metal can be used.

[0178] In addition, a material that undergoes a conversion reaction can also be used as the negative electrode active material. , cobalt oxide (CoO), nickel oxide (NiO), iron oxide (FeO), etc. A transition metal oxide that does not form an alloy with the metal may be used as the negative electrode active material. Further materials that can be produced include Fe2O3, CuO, Cu2O, RuO2, Cr2O3, etc. oxide, CoS 0.89 , NiS, CuS and other sulfides, Zn3N2, Cu3N, Ge3 Nitrides such as N4, phosphides such as NiP2, FeP2, CoP3, FeF3, BiF3, etc. Fluoride is one example.

[0179] The conductive additive and binder that can be contained in the negative electrode active material layer are the same as those that can be contained in the positive electrode active material layer. The same materials as the conductive additive and binder can be used.

[0180] <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.

[0181] [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:

[0182] 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 storage device can be prevented from rising due to an internal short circuit or overcharging. Even if the battery is damaged, it can prevent the battery from exploding or catching fire. 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.

[0183] 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.

[0184] The electrolyte used in the electricity storage device is free from granular waste 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.

[0185] 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 Additives such as methyl methyl acrylate compounds may be added. The concentration of the additives may be, for example, 0. It is sufficient to set the content to 1 wt% or more and 5 wt% or less.

[0186] Alternatively, a polymer gel electrolyte may be used in which a polymer is swollen with an electrolytic solution.

[0187] The use of polymer gel electrolyte increases safety against leakage etc. The pond can be made thinner and lighter.

[0188] Gelled polymers include silicone gel, acrylic gel, and acrylonitrile gel. , polyethylene oxide gel, polypropylene oxide gel, fluorine-based polymer For example, a gel of a polyalcohol such as polyethylene oxide (PEO) can be used. Polymers with an alkylene oxide structure, PVDF, polyacrylonitrile, etc. For example, PVDF and hexafluoropropylene copolymers containing PVDF can be used. PVDF-HFP, a copolymer of propylene and propylene (HFP), can be used. The resulting polymer may have a porous shape.

[0189] 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.

[0190] Therefore, the positive electrode active material manufactured by the manufacturing method of one embodiment of the present invention can be applied to all-solid-state batteries. By applying this positive electrode active material to all-solid-state batteries, high safety and excellent characteristics are possible. Therefore, an all-solid-state battery with good electrical conductivity can be obtained.

[0191] This embodiment mode can be implemented in appropriate combination with other embodiment modes.

[0192] (Embodiment 5) In this embodiment, the positive electrode active material manufactured by the manufacturing method described in the previous embodiment is An example of the shape of the secondary battery will be described. For the materials, the description of the previous embodiments can be referred to.

[0193] [Coin-type secondary battery] First, an example of a coin-type secondary battery will be described. FIG. 12A shows a coin-type (single-layer flat type) FIG. 12B is a cross-sectional view of the secondary battery.

[0194] 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. 302 is insulated and sealed by 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 306 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 The negative electrode active material layer 309 is formed by bonding the negative electrode active material layer 309 to the negative electrode active material layer 309 .

[0195] The positive electrode 304 and the negative electrode 307 used in the coin-type secondary battery 300 are each an active material. The barrier layer need only be formed on one side.

[0196] The positive electrode can 301 and the negative electrode can 302 are made of nickel and aluminum, which are corrosion-resistant to the electrolyte. , titanium, or alloys thereof or alloys of these with 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 304. 7 and electrically connect to each other.

[0197] The negative electrode 307, the positive electrode 304, and the separator 310 are impregnated with an electrolyte, and as shown in FIG. 12B As shown, the positive electrode can 301 is placed downwards, and the positive electrode 304, separator 310, negative electrode 307, and negative electrode The cans 302 are stacked in this order, and the positive electrode can 301 and the negative electrode can 302 are secured together with a gasket 303 interposed therebetween. The coin-type secondary battery 300 is manufactured by crimping.

[0198] By using the positive electrode active material particles described in the above embodiment for the positive electrode 304, deterioration is reduced. This makes it possible to provide a highly safe coin-type secondary battery 300.

[0199] [Separator] The secondary battery preferably has a separator. The separator may be made of, for example, paper. Cellulose-containing fibers, nonwoven fabrics, glass fibers, ceramics, or nanofibers, including Ilon (polyamide), Vinylon (polyvinyl alcohol fiber), polyester, acrylic Use synthetic fibers such as styrene, polyolefin, and polyurethane. The separator is made into a bag shape and placed so that it encases either the positive or negative electrode. It is preferable to do so.

[0200] 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 mixture of these. As a ceramic material, for example, aluminum oxide can be used. Examples of the fluorine-based material include fluorine particles, silicon oxide particles, etc. PVDF, polytetrafluoroethylene, etc. can be used. For example, nylon, aramid (meta-aramid, para-aramid), etc. can be used. can.

[0201] Coating with ceramic materials improves oxidation resistance, making it suitable for separators during high-voltage charging and discharging. This can suppress the deterioration of the battery and improve the reliability of the secondary battery. By coating, the separator and electrodes can be more easily attached to each other, improving output characteristics. Coating polyamide materials, especially aramid, improves heat resistance, which contributes to the safety of secondary batteries. Safety can be improved.

[0202] For example, a polypropylene film is coated on both sides with a mixture of aluminum oxide and aramid. Alternatively, aluminum oxide may be applied to the surface of the polypropylene film that comes into contact with the positive electrode. Alternatively, the surface of the negative electrode that comes into contact with the carbon black may be coated with a mixed material of carbon black and aramid, and then coated with a fluorine-based material.

[0203] 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 temperature can be maintained, the capacity per volume of the secondary battery can be increased.

[0204] [Cylindrical secondary battery] An example of a cylindrical secondary battery will be described with reference to FIGS. 13A to 13D. As shown in FIGS. 13A and 13B, the battery 600 has a positive electrode cap (battery lid) 60 on the top surface. 1, and a battery can (external can) 602 on the side and bottom. and the battery can (external can) 602 are insulated by a gasket (insulating packing) 610. There are.

[0205] FIG. 13B is a schematic diagram showing a cross section of a cylindrical secondary battery. Inside the battery can 602, a strip-shaped positive electrode 604 and a negative electrode 606 are sandwiched with a separator 605 between them. Although not shown, the battery element is wound around a center pin. The battery can 602 is closed at one end and open at the other end. The material is nickel, aluminum, titanium, or other metals that are resistant to corrosion by the electrolyte. Alloys of these and alloys of these with other metals (e.g., stainless steel, etc.) can be used. In addition, to prevent corrosion by the electrolyte, it is preferable to coat the electrode with nickel, aluminum, etc. A battery element in which a positive electrode, a negative electrode, and a separator are wound inside the battery can 602 is preferably formed. The element is sandwiched between a pair of opposing insulating plates 608 and 609. The inside of the battery can 602 is filled with a non-aqueous electrolyte (not shown). A coin-type secondary battery can be used.

[0206] The positive and negative electrodes used in cylindrical secondary 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.

[0207] 13C, a plurality of secondary batteries 600 are disposed between conductive plates 613 and 614. The secondary batteries 600 may be sandwiched between the secondary batteries 600 to form a module 615. They may be connected in series or in parallel and then in series. By configuring a module 615 having a plurality of secondary batteries 600, a large It is possible to extract sufficient power.

[0208] 13D is a top view of module 615. Conductive plate 613 is shown with dashed lines for clarity. As shown in FIG. 13D, the module 615 electrically connects a plurality of secondary batteries 600. A conductive plate 613 is provided on the conductive wire 616. Furthermore, a temperature control device 617 may be provided between the plurality of secondary batteries 600. When the secondary battery 600 is overheated, the temperature control device 617 cools the secondary battery 600. If the temperature controller 617 is too cold, it can be heated. The performance of the Joule 615 is less affected by the outside temperature.

[0209] The positive electrode 604 is formed using the positive electrode active material manufactured by the manufacturing method described in the above embodiment. As a result, the cylindrical secondary battery 600 can be made less susceptible to deterioration and highly safe.

[0210] [Structure example of power storage device] Another structural example of the power storage device will be described with reference to FIGS.

[0211] 14A and 14B are diagrams showing the appearance of the power storage device. 0 and a secondary battery 913. A label 910 is attached to the secondary battery 913. Furthermore, as shown in FIG. 14B, the power storage device has a terminal 951, a terminal 952, an antenna 914 and an antenna 915.

[0212] The circuit board 900 has a terminal 911 and a circuit 912. The terminal 911 is connected to a terminal 951. , 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, etc. may also be used.

[0213] 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, antenna 914 or antenna 915 may be used. The flat conductor may function as one of the conductors for electric field coupling. In other words, the capacitor has two conductors, one of which is an annulus. The antenna 914 or the antenna 915 may be activated. Instead, power can be exchanged using an electric field.

[0214] 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.

[0215] The power storage device has a layer 916 between the antenna 914 and the secondary battery 913 and an antenna 915. The layer 916 has a function of shielding an electromagnetic field generated by the secondary battery 913, for example. For example, a magnetic material can be used as 16 .

[0216] The structure of the power storage device is not limited to that shown in FIG.

[0217] For example, as shown in FIGS. 15A and 15B, the secondary battery 91 shown in FIGS. 14A and 14B 3, an antenna may be provided on each of a pair of opposing surfaces. 15A is an external view seen from one side of the pair of surfaces, and FIG. 15B is an external view seen from the other side of the pair of surfaces. 14A and 14B are the same as those of the power storage device shown in FIG. The description of the power storage device shown in FIGS. 14A and 14B can be used as appropriate.

[0218] As shown in FIG. 15A, a layer 916 is sandwiched between one of the two surfaces of a secondary battery 913 and an antenna 9 15B, a layer 917 is provided on the other of the pair of surfaces of the secondary battery 913. The layer 917 is provided to receive the electromagnetic field from the secondary battery 913, for example. The layer 917 has a shielding function. For example, a magnetic material can be used as the layer 917.

[0219] By adopting the above structure, the size of both the antenna 914 and the antenna 915 can be increased. It is possible.

[0220] 15C and 15D, the secondary battery 913 shown in FIGS. 14A and 14B Of these, a separate antenna may be provided on each of the pair of opposing surfaces. FIG. 15D is an external view seen from one side of the pair of surfaces, and FIG. 15C is an external view seen from the other side of the pair of surfaces. 14A and 14B are the same as those of the power storage device shown in FIG. The description of the power storage device shown in FIGS. 14A and 14B can be used as appropriate.

[0221] As shown in FIG. 15C, a layer 916 is sandwiched between one of the two surfaces of the secondary battery 913 and an antenna 9 14 and an antenna 915 are provided, and as shown in FIG. 15D, a pair of surfaces of the secondary battery 913 An antenna 918 is provided on the other side of the layer 917. The antenna 918 has a function of performing data communication with external devices. Antennas of applicable shapes can be applied to the antenna 914 and the antenna 915. As a communication method between the power storage device and other devices via the antenna 918, NFC or the like is used. A response method that can be used between the device and other devices can be applied.

[0222] Alternatively, as shown in FIG. 16A, the display device 9 is connected to the secondary battery 913 shown in FIGS. 14A and 14B. The display device 920 is electrically connected to the terminal 911 via the terminal 919. It is not necessary to provide the label 910 in the area where the display device 920 is provided. 14A and 14B. The same parts as those in the power storage device shown in FIG. 14A and 14B are shown in FIG. The description of the power storage device shown in 2. above can be used as appropriate.

[0223] 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 electrophotographic display, or the like. For example, an electroluminescence (EL) display device can be used. By using the par, the power consumption of the display device 920 can be reduced.

[0224] 16B, the sensor 92 is connected to the secondary battery 913 shown in FIGS. 14A and 14B. The sensor 921 is electrically connected to the terminal 911 via the terminal 922. 14A and 14B. The description of the power storage device shown in 14B can be used as appropriate.

[0225] The sensor 921 may be, for example, a sensor for detecting displacement, position, velocity, acceleration, angular velocity, rotation speed, distance, light, etc. , liquid, magnetic, temperature, chemical, sound, time, hardness, electric field, current, voltage, power, radiation, flow It is sufficient if it has the function of measuring volume, humidity, gradient, vibration, odor, or infrared. By providing the sensor 921, for example, data indicating the environment in which the power storage device is placed can be acquired. It is also possible to detect a signal (such as temperature) and store it in memory within the circuit 912.

[0226] Furthermore, an example of the structure of the secondary battery 913 will be described with reference to FIGS.

[0227] The secondary battery 913 shown in FIG. 17A has a terminal 951 and a terminal 952 provided inside a housing 930. The battery has a wound body 950. The wound body 950 is impregnated with an electrolyte inside the housing 930. The terminal 952 is in contact with the housing 930, and the terminal 951 is in contact with the housing 930 by using an insulating material or the like. 17A, for the sake of convenience, the housing 930 is shown separately. However, in reality, the wound body 950 is covered by the housing 930, and the terminals 951 and 952 are The housing 930 is made of a metal material (for example, aluminum) Alternatively, a resin material can be used.

[0228] As shown in FIG. 17B, the housing 930 shown in FIG. 17A may be formed from a plurality of materials. For example, the secondary battery 913 shown in FIG. 17B may be formed by bonding a housing 930a and a housing 930b together. The housings 930a and 930b are joined together, and a winding body 950 is provided in the area surrounded by the housings 930a and 930b. It is being done.

[0229] 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 secondary battery 913 is formed, If the shielding of the electric field by the housing 930a is small, the shielding of the electric field by the housing 930a can be suppressed. Antennas such as antenna 914 and antenna 915 may be provided inside the housing 930b. For example, a metal material can be used.

[0230] Furthermore, the structure of the wound body 950 is shown in Fig. 18. The wound body 950 is made up of a negative electrode 931 and a positive electrode 932. The winding body 950 has a pole 932 and a separator 933. The negative electrode 931 and the positive electrode 932 are stacked one on top of the other, and the laminated sheet is wound to form a wound body. The negative electrode 931, the positive electrode 932, and the separator 933 may be further laminated. You can stack several of them.

[0231] The negative electrode 931 is connected to the terminal 911 shown in FIG. 14 via one of the terminals 951 and 952. The positive electrode 932 is connected to the terminal 91 shown in FIG. 14 via the other of the terminals 951 and 952. Connected to 1.

[0232] By using the positive electrode active material particles described in the above embodiment for the positive electrode 932, deterioration is reduced. This makes it possible to provide a highly safe secondary battery 913.

[0233] [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 will have at least one flexible portion. If the secondary battery is mounted in an electronic device that also has a battery, it can be bent according to the deformation of the electronic device. can.

[0234] A laminated secondary battery 980 will be described with reference to Figures 19A to 19C. The Nate type secondary battery 980 has a wound body 993 shown in FIG. 19A. The wound body 993 is The wound body 993 includes a negative electrode 994, a positive electrode 995, and a separator 996. As in the case of the wound body 950 described above, a separator 996 is sandwiched between a negative electrode 994 and a positive electrode 995. are stacked one on top of the other, and the laminated sheet is wound up.

[0235] The number of layers of the negative electrode 994, the positive electrode 995, and the separator 996 is determined as required. The negative electrode 994 is connected to the lead electrode 997 and the lead 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 and the lead electrode 998 are connected to a positive electrode current collector (not shown).

[0236] As shown in FIG. 19B, a film 981 serving 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 together by thermocompression bonding or the like. Thus, a secondary battery 980 can be fabricated as shown in FIG. 19C. The film 981 has a lead electrode 997 and a lead electrode 998, and the film 981 has a recess. The inside of the tube 982 is impregnated with an electrolyte.

[0237] 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 material such as a resin. If a resin material is used as the material, when external force is applied, the film 981 and the recessed portion The film 982 can be deformed to produce a flexible secondary battery. can be done.

[0238] Although Fig. 19B and Fig. 19C show an example using two films, it is also possible to use one film. The film is folded to form a space, and the above-mentioned wound body 993 is housed in the space. That's fine.

[0239] By using the positive electrode active material particles described in the previous embodiment for the positive electrode 995, deterioration is reduced. This makes it possible to provide a highly safe secondary battery 980.

[0240] 19A to 19C, a wound body is provided in a space formed by a film that serves as an exterior body. 20, for example, as shown in FIG. 20, A secondary battery having a plurality of rectangular positive electrodes, separators, and negative electrodes is placed in the space formed by the film. It may also be a battery.

[0241] The laminated secondary battery 500 shown in FIG. 20A includes a positive electrode current collector 501 and a positive electrode active material layer a positive electrode 503 having a negative electrode current collector 504 and a negative electrode active material layer 505; 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 the battery 09. The exterior body 509 is filled with an electrolyte 508. The electrolyte solution shown in form 2 can be used.

[0242] In the laminated secondary battery 500 shown in FIG. 20A, a positive electrode current collector 501 and a negative electrode current collector The current collector 504 also serves as a terminal for electrical contact with the outside. The body 501 and the negative electrode current collector 504 are arranged so as to be partially exposed to the outside from the exterior body 509. In addition, the positive electrode current collector 501 and the negative electrode current collector 504 may be disposed outside the outer casing 509. Instead, a lead electrode is used to connect the lead electrode to the positive electrode current collector 501 or the negative electrode current collector The lead electrode may be exposed to the outside by ultrasonic bonding to the body 504 .

[0243] In the laminated secondary battery 500, the exterior body 509 is made of, for example, polyethylene, poly A film made of propylene, polycarbonate, ionomer, polyamide, etc. is coated with an A thin metal film with excellent flexibility, such as aluminum, stainless steel, copper, or nickel, is applied, and the metal is further On the metallic thin film, an insulating synthetic resin such as polyamide resin or polyester resin is applied as the outer surface of the exterior body. A three-layer laminate film provided with an oil film can be used.

[0244] An example of the cross-sectional structure of a laminated secondary battery 500 is shown in FIG. For simplicity, an example consisting of two current collectors is shown, but in reality, it is composed of multiple electrode layers. do.

[0245] In FIG. 20B, as an example, the number of electrode layers is set to 16. The secondary battery 500 is flexible. In FIG. 20B, the negative electrode current collector 504 has eight layers and the positive electrode current collector The structure shown in FIG. 20B is a structure of 16 layers in total, with 8 layers of the body 501. The cross section shows eight layers of negative electrode current collector 504 ultrasonically bonded together. The number of electrode layers is not limited to 16, and may be more or less. In addition, when the number of electrode layers is small, a thin secondary battery can be obtained. This allows the secondary battery to be made highly flexible.

[0246] An example of the external appearance of a laminated secondary battery 500 is shown in FIGS. 21 and 22. 1 and 22 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.

[0247] 23A shows the external appearance of the positive electrode 503 and the negative electrode 506. The positive electrode 503 has a positive electrode current collector 501. The positive electrode active material layer 502 is formed on the surface of the positive electrode current collector 501. The negative electrode 50 has a region where the positive electrode current collector 501 is partially exposed (hereinafter referred to as a tab region). 6 has a negative electrode current collector 504, and a negative electrode active material layer 505 is formed on the surface of the negative electrode current collector 504. The negative electrode 506 has a region where the negative electrode current collector 504 is partially exposed, i.e., a tab region. The area and shape of the tab regions of the positive electrode and negative electrode are not limited to the example shown in FIG. .

[0248] [Method for manufacturing laminated secondary batteries] Here, an example of a method for manufacturing the laminated secondary battery shown in FIG. 21 will be described with reference to FIG. This will be explained using Figure 23B and Figure 23C.

[0249] First, the negative electrode 506, the separator 507, and the positive electrode 503 are stacked. The negative electrode 506, separator 507, and positive electrode 503 are shown. Here, five pairs of negative electrodes and four pairs of positive electrodes are shown. Next, the bonding of the tab regions of the positive electrode 503 and the tab region of the positive electrode on the outermost surface are shown. The positive lead electrode 510 is joined to the substrate 510. For the joining, ultrasonic welding or the like may be used. Similarly, the tab regions of the negative electrodes 506 are joined together, and the negative electrode lead is connected to the tab region of the negative electrode on the outermost surface. The electrodes 511 are bonded.

[0250] Next, the negative electrode 506 , the separator 507 and the positive electrode 503 are placed on the exterior body 509 .

[0251] Next, as shown in Figure 23C, exterior body 509 is folded at the portion indicated by the dashed line. The outer periphery of the exterior body 509 is bonded. For example, thermocompression bonding may be used for bonding. The electrode 504 is joined to a part (or one side) of the exterior body 509 so that the electrolyte 508 can be poured into the electrode 504. An area where the air is not blown into the tank (hereinafter referred to as an inlet) is provided.

[0252] Next, the electrolyte 508 is introduced into the inside of the exterior body 509 through an inlet provided in the exterior body 509. The introduction of the electrolytic solution 508 is preferably carried out under a reduced pressure atmosphere or an inert atmosphere. Finally, the inlet is joined. In this way, a laminated secondary battery is completed. A secondary battery 500 can be fabricated.

[0253] By using the positive electrode active material particles described in the above embodiment for the positive electrode 503, deterioration is reduced. This makes it possible to provide a highly safe secondary battery 500.

[0254] [Bendable secondary battery] Next, an example of a bendable secondary battery will be described with reference to FIGS.

[0255] Figure 24A shows a schematic top view of a bendable battery 250. 24A and 24D show the cut lines C1-C2, C3-C4, and A in FIG. 24A, respectively. The battery 250 includes an exterior body 251 and a battery pack 252 therein. The positive electrode 211a and the negative electrode 211b are electrically connected to each other. The lead 212a electrically connected to the negative electrode 211b and the lead 212b electrically connected to the negative electrode 211b are externally connected. The positive electrode 211a extends outside the outer casing 251. In addition to the negative electrode 211b, an electrolyte (not shown) is enclosed.

[0256] The positive electrode 211a and the negative electrode 211b of the battery 250 will be described with reference to FIG. 25. FIG. 25A illustrates the stacking order of the positive electrode 211a, the negative electrode 211b, and the separator 214. FIG. 25B shows the positive electrode 211a and the negative electrode 211b, as well as the leads 212a and 2 is a perspective view showing the lead 212b.

[0257] As shown in FIG. 25A, the battery 250 includes a plurality of strip-shaped positive electrodes 211a, a plurality of strip-shaped negative electrodes 211b, and a plurality of strip-shaped negative electrodes 211c. The positive electrode 211a and the negative electrode 211b have a plurality of separators 214. Each of the positive electrodes 211a has a protruding tab portion and a portion other than the tab. A positive electrode active material layer is formed on the other part of the negative electrode 211b, and a negative electrode active material layer is formed on the other part of the negative electrode 211b. An active material layer is formed.

[0258] The surfaces of the positive electrode 211a on which the positive electrode active material layer is not formed and the surfaces of the negative electrode 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 the porous layer is not formed are in contact with each other. will be done.

[0259] 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. Data 214 is shown by a dotted line.

[0260] As shown in FIG. 25B, the positive electrodes 211a and the leads 212a are connected to the joints 215a. The negative electrodes 211b and the leads 212b are electrically connected at the joints 215. Electrically connected at b.

[0261] Next, exterior body 251 will be described with reference to FIGS. 24B, 24C, 24D, and 24E. do.

[0262] 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 at the folded portion 261 and a pair of sealing portions 2 The pair of sealing portions 262 are connected to the positive electrode 211a and the negative electrode 211b. The seal portion 26 is provided on either side of the pole 211b and can also be called a side seal. 3 has a portion overlapping with the lead 212a and the lead 212b, and is also called a top seal. This can be done.

[0263] The exterior body 251 has a ridge line 271 and a valley line 272 at the portion overlapping the positive electrode 211a and the negative electrode 211b. It is preferable that the sealing portion 26 of the exterior body 251 has a wave shape in which the grooves 72 are arranged alternately. 2 and the seal portion 263 are preferably flat.

[0264] FIG. 24B is a cross section cut at the part overlapping with the ridge line 271, and FIG. 24C is a cross section cut at the part overlapping with the valley line 272. 24B and 24C are cross sections cut at the overlapping portion. 11a and the negative electrode 211b in the width direction.

[0265] Here, the end of the negative electrode 211b in the width direction, i.e., the end of the negative electrode 211b and the seal portion 262 The distance between the battery 250 and the electrode 251 is defined as La. In this way, the positive electrode 211a and the negative electrode 211b are deformed so as to be displaced from each other in the length direction. In this case, if the distance La is too short, the exterior body 251 will rub strongly against the positive electrode 211a and the negative electrode 211b. In particular, if the metal film of the exterior body 251 is exposed, In this case, the metal film may be corroded by the electrolyte. It is preferable to set the distance La as long as possible. On the other hand, if the distance La is set too large, , the volume of the battery 250 increases.

[0266] 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 b and the seal portion 262.

[0267] More specifically, the total thickness of the stacked positive electrode 211a and negative electrode 211b is defined as thickness t. When the distance La is 0.8 times or more and 3.0 times or less, preferably 0.9 times or more and 2.0 times or less, of the thickness t, It is preferable that the distance La is 5 times or less, and more preferably 1.0 to 2.0 times. By setting the thickness within this range, a compact battery with high reliability against bending can be realized. .

[0268] In addition, when the distance between the pair of seal portions 262 is a distance Lb, the distance Lb is and is sufficiently larger than the width of the negative electrode 211b (here, the width Wb of the negative electrode 211b). This is preferable because the positive electrode Even if the positive electrode 211a and the negative electrode 211b come into contact with the exterior body 251, Since a part of 11b can be shifted in the width direction, the positive electrode 211a and the negative electrode 211b can be shifted in the width direction. This effectively prevents the attachment body 251 from rubbing against each other.

[0269] 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 1.6 times or more and 6.0 times or less, preferably 1.8 times, the thickness t of 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. .

[0270] 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: It's nice.

[0271]

number

[0272] 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 is between 1.0 and 2.0.

[0273] FIG. 24D is a cross section including the lead 212a, showing the battery 250, the positive electrode 211a, and the negative electrode 212b. As shown in FIG. 24D, the bending portion 261 corresponds to the cross section of the pole 211b in the longitudinal direction. In this case, a space is formed between the end portions of the positive electrode 211a and the negative electrode 211b in the length direction and the exterior body 251. It is preferred to have 273.

[0274] FIG. 24E shows a cross-sectional schematic diagram of the battery 250 when bent. This corresponds to the cross section taken along the line B1-B2 in the figure.

[0275] When the battery 250 is bent, the part of the exterior body 251 located on the outside of the bend stretches, and the part located on the inside More specifically, the part located on the outside of the exterior body 251 is deformed so as to shrink. On the other hand, the outer casing 251 is deformed so that the amplitude of the wave becomes smaller and the period of the wave becomes larger. The part located inside the In this way, the deformation of the exterior body 251 causes the load acting on the exterior body 251 due to bending. Since the stress is relieved, the material that constitutes the exterior body 251 itself does not need to expand or contract. As a result, the battery 250 can be bent with a small force without damaging the exterior body 251.

[0276] Furthermore, as shown in FIG. 24E, when the battery 250 is bent, the positive electrode 211a and the negative electrode 211b At this time, the plurality of stacked positive electrodes 211a and negative electrodes 21 1b, one end of the seal portion 263 side is fixed by the fixing member 217, so that the bent portion 2 The deviation amount is larger the closer to the positive electrode 211a. The stress applied to the positive electrode 211a and the negative electrode 211b is alleviated, and the positive electrode 211a and the negative electrode 211b themselves are expanded. As a result, the positive electrode 211a and the negative electrode 211b can be easily compressed without being damaged. You can bend a 250.

[0277] In addition, a space 273 is provided between the positive electrode 211a and the negative electrode 211b and the exterior body 251. When the battery is bent, the positive electrode 211a and the negative electrode 211b located on the inside are bent by the outer casing 25. It can move relative to 1 without touching it.

[0278] The battery 250 illustrated in FIGS. 24 and 25 does not break the exterior body even when repeatedly bent and stretched. Damage to the positive electrode 211a and the negative electrode 211b is unlikely to occur, and the battery characteristics are unlikely to deteriorate. The battery 250 has a positive electrode 211a containing the positive electrode active material described in the previous embodiment. By using particles, it is possible to obtain a secondary battery that is even less susceptible to deterioration and is highly safe.

[0279] This embodiment mode can be implemented in appropriate combination with other embodiment modes.

[0280] (Sixth embodiment) In this embodiment, an example in which a secondary battery according to one embodiment of the present invention is mounted on an electronic device will be described. do.

[0281] First, as explained in part of the fourth embodiment, a bendable secondary battery is mounted on an electronic device. An example is shown in Figure 26. An example of an electronic device that uses a bendable secondary battery is a Revision equipment (also called television or television receiver), computer monitors, etc. Digital cameras, digital video cameras, digital photo frames, mobile phones ( Mobile phones, also known as mobile phone devices, portable game machines, portable information terminals, sound reproducing devices, Examples include large game machines such as dick machines.

[0282] In addition, the flexible secondary battery can be mounted on the inner or outer wall of a house or building, or on the inside or outside of a car. It is also possible to incorporate it along the curved surface of the interior or exterior of the vehicle.

[0283] FIG. 26A shows an example of a mobile phone. A mobile phone 7400 is assembled in a housing 7401. In addition to the built-in display 7402, operation buttons 7403, external connection port 7404, speaker The mobile phone 7400 is equipped with a power supply 7405, a microphone 7406, and the like. It has 7407.

[0284] FIG. 26B shows the mobile phone 7400 in a bent state. When the entire structure is deformed and curved by an external force, the secondary battery 74 disposed inside the structure is The secondary battery 7407 is also bent. At this time, the state of the bent secondary battery 7407 is shown in FIG. 26C. The secondary battery 7407 is a thin secondary battery. The secondary battery 7407 is fixed in a bent state. The secondary battery 7407 has a lead electrode electrically connected to the current collector. There are.

[0285] FIG. 26D shows an example of a bangle-type display device. The portable display device 7100 has a housing 7101, a display unit 7102, operation buttons 7103, and a secondary battery 7104. FIG. 26E shows the bent state of the secondary battery 7104. When the device is worn on the user's arm in this state, the housing may deform, causing part or all of the secondary battery 7104 to bend. The degree of curvature at any point on the curve is expressed by the value of the radius of the corresponding circle. The radius of curvature is called the radius of curvature, and the reciprocal of the radius of curvature is called the curvature. Part or all of the main surface of the casing or secondary battery 7104 within a range of 150 mm or more The radius of curvature of the main surface of the secondary battery 7104 is 40 mm or more and 150 mm or less. Within this range, high reliability can be maintained.

[0286] FIG. 26F shows an example of a wristwatch-type mobile information terminal. Body 7201, display unit 7202, band 7203, buckle 7204, operation button 7205 , input / output terminal 7206, etc.

[0287] The portable information terminal 7200 is capable of carrying out mobile phone calls, e-mails, viewing and creating documents, playing music, and internet access. - It can run various applications such as internet communication and computer games. do.

[0288] 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 can be touched with a finger or a stylus. For example, the icon 72 displayed on the display unit 7202 can be operated by touching it. You can launch the application by touching 07.

[0289] 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 operation, silent mode activation and deactivation, power saving mode activation and deactivation, etc. For example, an operating system installed in the portable information terminal 7200 can The function of the operation button 7205 can also be freely set using the stem.

[0290] 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 operation is possible. You can also make calls.

[0291] The portable information terminal 7200 also has an input / output terminal 7206, and a connector for connecting to other information terminals. Data can be exchanged directly via the input / output terminal 7206. The charging operation can be performed by wireless power supply without going through the input / output terminal 7206. It is also possible.

[0292] The display portion 7202 of the portable information terminal 7200 includes the secondary battery of one embodiment of the present invention. For example, if the secondary battery 7104 shown in FIG. 26E is curved inside the housing 7201, Alternatively, it can be incorporated into the band 7203 in a bendable state.

[0293] 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 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.

[0294] FIG. 26G shows an example of a wristband-type display device. The display device 7300 includes a display unit 730 4 and includes the secondary battery of one embodiment of the present invention. The 7304 can also be equipped with a touch sensor and function as a mobile information terminal. It is also possible.

[0295] The display surface of the display unit 7304 is curved, and images can be 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. The situation can be changed.

[0296] 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 also possible to charge the device via the input / output terminals. The charging operation may be performed by wireless power supply without using the input / output terminals.

[0297] Next, an example of a foldable tablet terminal is shown in Figures 27A and 27B. The tablet terminal 9600 shown in FIGS. 27A and 27B includes a housing 9630a, a housing 9630b, A movable part 9640 that connects the housing 9630a and the housing 9630b, a display part 9631, a display mode Mode selector switch 9626, power switch 9627, power saving mode selector switch 9 625, a fastener 9629, and an operation switch 9628. The display unit 9631 has a flexible By using a panel with this property, it is possible to create a tablet terminal with a larger display area. FIG. 27A shows the tablet terminal 9600 in an open state, and FIG. 27B shows the tablet terminal 9600 in an open state. The retina terminal 9600 is shown in a closed state.

[0298] The tablet terminal 9600 also includes a battery storage device inside the housing 9630a and the housing 9630b. The power storage unit 9635 is connected to the housing 9630a through the movable portion 9640. It is located across 9630b.

[0299] A part of the display unit 9631 can be used as a touch panel area, and the user can operate the displayed operation keys. You can input data by touching the screen. You can also switch the keyboard display on the touch panel. By touching the area where the replacement button is displayed with your finger or a stylus, the display 9631 Keyboard buttons can be displayed.

[0300] A display mode changeover switch 9626 changes the display orientation between portrait and landscape. You can select between black and white and color display. The touch 9625 detects when in use by the light sensor built into the tablet terminal 9600. The display brightness can be optimized according to the amount of external light. In addition to optical sensors, other sensors such as gyros and acceleration sensors that detect tilt are also available. The device may be built-in.

[0301] FIG. 27B shows the tablet terminal in a closed state. The tablet terminal includes a housing 9630, a solar cell 9633, and a 9636. The charge / discharge control circuit 9634 includes a DC / DC converter 9636. As the battery 35, a secondary battery according to one embodiment of the present invention is used.

[0302] In addition, since the tablet terminal 9600 can be folded in half, when not in use, the housing 9630a and The housing 9630b can be folded so that the housing 9630a and the housing 9630b overlap each other. Since the display portion 9631 can be protected, the durability of the tablet terminal 9600 can be improved. Furthermore, the power storage unit 9635 using the secondary battery of one embodiment of the present invention has a high capacity and a good cycle life. Because of its excellent thermal properties, it is possible to provide a tablet device that can be used for a long period of time. do.

[0303] In addition, the tablet terminals shown in FIGS. 27A and 27B can display various information (static Functions that display images, videos, text images, etc., calendars, dates, or times, etc. A function to display information on the display unit, and a function to operate or edit information displayed on the display unit by touch input. It has the function of controlling the processing by various software (programs), etc. This can be done.

[0304] The solar cell 9633 attached to the surface of the tablet terminal supplies power to the touch panel, The solar cell 9633 can be supplied to a display unit, a video signal processor, or the like. The structure can be provided on one or both sides of the power storage unit 9630, and can efficiently charge the power storage unit 9635. It can be concluded that

[0305] The configuration and operation of the charge / discharge control circuit 9634 shown in FIG. 27B are shown in block form in FIG. 27C. A block diagram is shown and explained. In FIG. 27C, a solar cell 9633, a power storage body 9635, a DC / DC converter Converter 9636, converter 9637, switches SW1 to SW3, display unit 9631 The figure shows the storage battery 9635, the DC-DC converter 9636, and the converter 963 7. The switches SW1 to SW3 correspond to the charge / discharge control circuit 9634 shown in FIG. 27B. It becomes a place.

[0306] 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 for charging the storage battery 9635. The voltage is increased or decreased by a inverter 9636. When power is used from the 9633, switch SW1 is turned on and the converter 9637 The voltage is increased or decreased to the voltage required for the display unit 9631. When not displaying the data, turn switch SW1 off and switch SW2 on. The configuration may be such that the electric body 9635 is charged.

[0307] The solar cell 9633 is shown as an example of a power generating means, but is not particularly limited thereto. Power storage using other power generation methods such as piezoelectric elements and thermoelectric conversion elements For example, the power may be transmitted and received wirelessly (contactlessly). It is also possible to combine it with a contactless power transmission module that charges the battery, or other charging means. That's fine.

[0308] Another example of electronic equipment is shown in FIG. 28. In FIG. 28, a display device 8000 is a display device according to one embodiment of the present invention. 8 is an example of an electronic device using a secondary battery 8004 according to an embodiment. 8000 corresponds to a display device for receiving TV broadcasts, and includes a housing 8001, a display unit 8002, and a speaker unit. The secondary battery 8004 according to one embodiment of the present invention includes a housing 8003 and a secondary battery 8004. The display device 8000 is provided inside a body 8001. The display device 8000 receives power from a commercial power source. Alternatively, the power stored in the secondary battery 8004 can be used. Even when power cannot be supplied from a commercial power source due to a power outage or the like, the present invention The display device 8000 can be used by using the secondary battery 8004 as an uninterruptible power supply. do.

[0309] The display unit 8002 includes a liquid crystal display device, an emitting device having a light emitting element such as an organic EL element in each pixel, and Device, electrophoretic display device, DMD (Digital Micromirror Device) ce), PDP (Plasma Display Panel), FED (Field A semiconductor display device such as a reflective LED (emission display) can be used.

[0310] In addition to TV broadcast reception, display devices are also used for personal computers and advertising displays. , including all display devices for displaying information.

[0311] In FIG. 28, a stationary lighting device 8100 includes a secondary battery 81 according to one embodiment of the present invention. 8101, a housing 8102, a light source 8103, and a light source 8104. 28, the secondary battery 8103 is mounted in the housing 81. 8101 and a light source 8102 are installed inside a ceiling 8104. However, the secondary battery 8103 may be provided inside the housing 8101. The device 8100 can receive power from a commercial power source or can store power in a secondary battery 8103. Therefore, if the power supply from the commercial power source is interrupted due to a power outage, etc., Even when the 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.

[0312] 28 shows an example of a fixed lighting device 8100 provided on a ceiling 8104. However, the secondary battery according to one embodiment of the present invention is not limited to the ceiling 8104, but may be installed on other parts such as the side wall 8105 and the floor 8106. 106, it can be used for a fixed lighting device provided in a window 8107, etc., or it can be used for a tabletop lighting device. It can also be used in lighting devices of this type.

[0313] The light source 8102 may be an artificial light source that artificially obtains light using electricity. Specifically, incandescent lamps, fluorescent lamps and other discharge lamps, and light-emitting devices such as LEDs and organic EL elements The element is an example of the artificial light source.

[0314] In FIG. 28, 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 according to one embodiment of the present invention. The device 8200 includes a housing 8201, an air outlet 8202, a secondary battery 8203, and the like. 8 illustrates an example in which the secondary battery 8203 is provided in the indoor unit 8200. The battery 8203 may be provided in the outdoor unit 8204. Both the power supply 8201 and the power supply 8204 may be provided with a secondary battery 8203. The power supply can be supplied from a commercial power source, or the power stored in the secondary battery 8203 can be used. In particular, both the indoor unit 8200 and the outdoor unit 8204 may be equipped with secondary batteries 82 If 03 is installed, when power cannot be supplied from the commercial power source due to a power outage, etc. In addition, by using the secondary battery 8203 of one embodiment of the present invention as an uninterruptible power supply, The conditioner can be used.

[0315] In Figure 28, a separate type air conditioner consisting of an indoor unit and an outdoor unit is shown. As an example, it is an all-in-one air conditioner that has the functions of both the indoor unit and the outdoor unit in a single housing. The secondary battery according to one embodiment of the present invention can also be used in the conditioner.

[0316] In FIG. 28, 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, a refrigerator It has a storage compartment door 8302, a freezer compartment door 8303, a secondary battery 8304, etc. A secondary battery 8304 is provided inside the housing 8301. The electric refrigerator-freezer 8300 is It can receive power from a commercial power source, or use the power stored in the secondary battery 8304. Therefore, when power cannot be supplied from the commercial power source due to a power outage, etc. However, by using the secondary battery 8304 of one embodiment of the present invention as an uninterruptible power supply, It will be possible to use the 8300-capacity refrigerator.

[0317] In addition, during times when electronic devices are not in use, especially when the total amount of power that can be supplied by the commercial power supplier is low, 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 battery, it is possible to prevent power usage rates from increasing outside of the above time periods. For example, in the case of the electric refrigerator-freezer 8300, when the temperature is low and the refrigerator compartment door 830 2. During the night when the freezer door 8303 is not opened or closed, the secondary battery 8304 stores power. Then, as the temperature rises, the refrigerator door 8302 and the freezer door 8303 are opened and closed. By using the secondary battery 8304 as an auxiliary power source during the daytime, the daytime power usage rate can be kept low.

[0318] In addition to the electronic devices described above, the secondary battery according to one embodiment of the present invention can be mounted in various electronic devices. According to one embodiment of the present invention, a secondary battery with little deterioration and high safety can be provided. Therefore, when the secondary battery according to one embodiment of the present invention is installed in the electronic device described in this embodiment, This makes it possible to make electronic devices with a longer life and higher safety.

[0319] This embodiment mode can be implemented in appropriate combination with other embodiment modes.

[0320] (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.

[0321] When a secondary battery is installed in a vehicle, it becomes a hybrid vehicle (HV), an electric vehicle (EV), or a plastic vehicle (PVE). Next-generation clean energy vehicles such as hybrid electric vehicles (PHV or PHEV) It can be achieved.

[0322] FIG. 29A illustrates a vehicle using a secondary battery according to one embodiment of the present invention. The car 8400 is an electric car that uses an electric motor as a power source for driving. Alternatively, an electric motor and an engine can be selected and used as the power source for driving. By using the secondary battery according to one embodiment of the present invention, A vehicle with a long range can be realized. The automobile 8400 also has a secondary battery. The secondary battery not only drives the electric motor 8406 but also the headlights 8401 and the room light. Power can be supplied to a light emitting device such as a light (not shown).

[0323] In addition, the secondary battery is used to power the speedometer, tachometer, and other displays of the automobile 8400. The secondary battery can supply power to the navigation device of the automobile 8400. The present invention can provide power to semiconductor devices such as mobile terminals.

[0324] The car 8500 shown in FIG. 29B has a secondary battery 8024 that is plugged in. It can be charged by receiving power from an external charging facility using a contactless power supply system or other methods. FIG. 29B shows a diagram of a charging device 8021 mounted on a ground and a charging station 8500. The secondary battery 8024 is shown being charged via a cable 8022. For charging methods and connector specifications, please refer to the specified CHAdeMO (registered trademark) or Combo. The charging device 8021 is a charging station installed in a commercial facility. For example, plug-in technology can be used to The secondary battery 8024 installed in the automobile 8500 can be charged by the power supply. Charging is performed by converting AC power to DC power via a converter such as an AC-DC converter. It is possible.

[0325] 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, a power transmission device is installed on the road or exterior wall. By incorporating this technology, charging can be carried out not only when the vehicle is stopped but also while the vehicle is moving. This method may be used to transmit and receive power between vehicles. A solar cell may be provided to charge the secondary battery when the vehicle is stopped or running. The power can be supplied by an electromagnetic induction method or a magnetic resonance method.

[0326] FIG. 29C shows an example of a two-wheeled vehicle using the secondary battery of one embodiment of the present invention. The scooter 8600 shown includes a secondary battery 8602, side mirrors 8601, and a turn signal light 860. 3. The secondary battery 8602 can supply electricity to the direction indicator light 8603.

[0327] In addition, the scooter 8600 shown in FIG. 29C has a secondary battery 8602 in the storage space under the seat 8604. The secondary battery 8602 can be stored in the under-seat storage 8604 even if it is small. It can be stored in under-seat storage space 8604.

[0328] According to one embodiment of the present invention, a secondary battery that is less prone to deterioration and highly safe can be obtained. Therefore, by installing it in a vehicle, it is possible to prevent a decrease in cruising range and acceleration performance. Furthermore, the vehicle can be made highly safe. In this case, for example, during peak power demand, It is possible to avoid using commercial power sources during peak power demand periods. If this can be avoided, it will contribute to energy conservation and reduction of carbon dioxide emissions. In addition, cobalt is used as a secondary battery because it has little deterioration and can be used for a long period of time. This will reduce the amount of rare metals used, including

[0329] This embodiment mode can be implemented in appropriate combination with other embodiment modes. [Example]

[0330] In this example, LiMO2 manufactured by a manufacturing method according to one embodiment of the present invention will be described. The manufacturing method will be described with reference to FIG. 1, FIG. 3B and Table 2.

[0331] <Preparation of Each Sample of LiMO2> First, a mixture 902 containing magnesium and fluorine was prepared (Steps S11 to Step S14). Lithium fluoride and magnesium fluoride were weighed so that the molar ratio of LiF:MgF2 = 1:3, and acetone was added as a solvent, followed by wet mixing and pulverization. The mixing and pulverization were performed using a ball mill with zirconia balls at 400 rpm for 12 hours. The processed material was recovered to obtain the mixture 902.

[0332] Next, lithium cobaltate was prepared as a composite oxide containing lithium and cobalt. More specifically, Celsid C-10N manufactured by Nippon Chemical Industry Co., Ltd. was prepared (Step S25).

[0333] Next, in Step S31, the mixture 902 was weighed so that the atomic weight of magnesium in the mixture 902 was 0.5 mol% relative to the atomic weight of cobalt in lithium cobaltate. The mixing was performed dry using a ball mill with zirconia balls at 150 rpm for 1 hour. Thereafter, the mixture was recovered (Step S32) to obtain the mixture 903 (Step S33).

[0334] Next, the mixture 903 was placed in an alumina crucible (aluminum oxide crucible) and annealed in a muffler furnace (Step S34). The annealing conditions vary depending on each sample and are as shown in Table 2. The temperature increase was set at 200 °C / h, and the temperature decrease was performed over 10 hours or more. The heat-treated material was recovered and sieved (Step S35) to obtain each sample (Comparative Sample 1, Comparative Sample 2, and Sample 3) (Step S36). Also, the actually used alumina crucible was [[]]recovered.​​​​​​ It is shown in FIG. 30. FIG. 30A shows the state before covering the alumina crucible with a lid, and FIG. 30B shows the state when the alumina crucible is covered. As shown in FIG. 30B, Sample 3 was prepared by covering the alumina crucible.

[0335] Sample 3 was prepared by the production method of one aspect of the present invention. Comparative Sample 1 and Sample 3 differ in annealing time and O2 conditions. Comparative Sample 2 and Sample 3 differ in O2 conditions . Note that Comparative Sample 1 and Comparative Sample 2 were prepared under an O2 condition of "flow".

[0336]

Table 2

[0337] <Annealing Method of Each Sample of LiMO2> Up to S33, it is the same for all samples. The annealing method of S34 is different for each sample. The conceptual diagram at the time of annealing is as shown in FIG. 3B.

[0338] In Table 2, "sample weight" is the weight of the annealed mixture 903.

[0339] In Table 2, "annealing temperature" is the temperature at the time of annealing, and "annealing time" is the time for maintaining the annealing temperature.

[0340] In Table 2, "O2 condition" is the method of introducing O2 into the space 102 in the heating furnace, and "flow" means annealing was performed while introducing O2 at a flow rate of 10 L / min, and "purge" means that the space 102 in the heating furnace was replaced with O2 before annealing, and then annealing was performed.

[0341] <Production of Battery Cell> Next, the comparative samples 1, 2 and 3 obtained above were used as positive electrodes. The positive electrodes were fabricated using AB and PVDF as the active materials. A slurry of AB:PVDF = 95:3:2 (weight ratio) was applied to the current collector. NMP was used as the solvent for the slurry.

[0342] 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 electrode loading is approximately 7 mg / cm 2 The electrode density was set to >3.8 g / cc.

[0343] Using the prepared positive electrode, a CR2032 type coin (diameter 20 mm, height 3.2 mm) was A battery cell of this type was fabricated.

[0344] The counter electrode was made of lithium metal.

[0345] 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). For the secondary battery, 2 wt% vinylene carbonate (VC) was added to the electrolyte. .

[0346] The separator was made of polypropylene with a thickness of 25 μm.

[0347] The positive electrode can and the negative electrode can were made of stainless steel (SUS).

[0348] <Charge / discharge efficiency measurement> Batteries fabricated using the obtained Comparative Sample 1, Comparative Sample 2, and Sample 3, respectively The cycle characteristics of the cells were measured. Charging was performed under CCCV (1.0 C, 4.6 V, termination current 0.1 C), and discharging was performed under CC (1.0 C, 2.5 V) to evaluate the cycle characteristics at 25°C . The results are shown in Fig. 31

[0349] From Fig. 31, it was found that Sample 3 fabricated according to one aspect of the present invention exhibited better cycle characteristics than Comparative Sample 2. Also, Sample 3 exhibited cycle characteristics equivalent to those of Comparative Sample 1 . However, from Table 2, it can be seen that Sample 3 can fabricate the positive electrode active material with an annealing time one-third that of Comparative Sample 1. Therefore, it can be said that Sample 3 can fabricate a positive electrode active material with good characteristics in a short time. From the above, it was found that according to one aspect of the present invention, a positive electrode active material exhibiting good characteristics can be fabricated in a short time. Also, it was found that Sample 3 can process a relatively large mass of 30 g at one time. Therefore, it was found that according to one aspect of the present invention, a large amount of positive electrode active material having good characteristics can be fabricated in a short time . <EXAMPLE> In this example, LiMO2 fabricated by a fabrication method according to one aspect of the present invention different from that of Example 1 will be described. The fabrication method will be described using Figs. 1, 3B, and Table 3 .

Example

[0350] In this example, LiMO2 fabricated by a fabrication method according to one aspect of the present invention different from that of Example 1 will be described. The fabrication method will be described using Figs. 1, 3B, and Table 3 The mixture 902 was fabricated through steps S11 to S14 in Fig. 1. Mixing and pulverization

[0351] <Fabrication of Each Sample of LiMO2> were performed in the same manner as in Example 1, except that they were performed dry. Next, step S3 of Example 1 was performed As in steps S1 to S33, CellSeed C-10N and mixture 902 are mixed, and mixture 9 I got 03.

[0352] Next, the mixture 903 was placed in an alumina crucible and annealed in a muffle furnace (step S34 The annealing conditions differed for each sample and are shown in Table 3. The alumina crucible is a small, deep container as shown in container 116a in FIG. 1.5 g of sample was placed in each deep container, and 12 such containers were lined up in a muffle furnace and annealed. The other conditions were the same as in Example 1.

[0353] [Table 3]

[0354] <Battery cell production> Next, the same procedure as in Example 1 was carried out using the comparative sample 4 and sample 5 obtained above. A battery cell was fabricated.

[0355] <Charge / discharge efficiency measurement> The cycle characteristics of the battery cells of the obtained comparative sample 4 and sample 5 were measured. CCV (0.2C, 4.6V, final current 0.02C), discharge CC (0.2C, 2.5V The cycle characteristics were evaluated at 25°C. The results are shown in Figure 32.

[0356] As shown in Figure 32, Sample 5, which was annealed with the lid on, exhibited a significantly higher temperature than the comparison sample, which was annealed without the lid on. It was found that the cycle characteristics were much better than those of Sample 4. Even if the container is deep and covered, the cathode active material exhibits good characteristics. I found out that it can be made. [Explanation of symbols]

[0357] 101: Positive electrode active material, 100A-1: Positive electrode active material, 100C: Positive electrode active material, 102: Heating Furnace space, 116: Container, 116a: Container, 119: Space, 119a: Space, 120: Addition Heating furnace, 130: heating furnace, 132: belt conveyor, 134: container, 140: heating furnace, 14 2: material input section, 144: atmosphere control section, 146: recovery section, 200: active material layer, 201: Graphene compound, 211a: positive electrode, 211b: negative electrode, 212a: lead, 212b: lead 214: separator; 215a: joint; 215b: joint; 217: fixing member; 250: battery, 251: exterior body, 261: folding portion, 262: sealing portion, 263: seal 271: Ridge line; 272: Valley line; 273: Space; 300: Secondary battery; 301: Positive electrode can 302: negative electrode can, 303: gasket, 304: positive electrode, 305: positive electrode current collector, 306: Positive electrode active material layer, 307: negative electrode, 308: negative electrode current collector, 309: negative electrode active material layer, 310: Palator, 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: Outer casing, 510: Positive electrode lead, 511: Negative electrode lead, 600: secondary battery, 601: positive electrode cap, 602: battery can, 603: positive electrode terminal, 604 : positive electrode, 605: separator, 606: negative electrode, 607: negative electrode terminal, 608: insulating plate, 60 9: insulating plate, 611: PTC element, 612: safety valve mechanism, 613: conductive plate, 614: conductive board, 615: module, 616: conductor, 617: temperature control device, 900: circuit board, 9 02:Mixture, 902-3:Mixture, 903:Mixture, 903-2:Mixture, 903-3 : mixture, 904: positive electrode active material, 904-2: positive electrode active material, 904-3: positive electrode active material, 9 04-4: Positive electrode active material, 905: Mixture, 908: Mixture, 909: Mixture, 910: La Bell, 911: terminal, 912: circuit, 913: secondary battery, 914: antenna, 915: Antenna, 916: Layer, 917: Layer, 918: Antenna, 919: Terminal, 920: Display device , 921: sensor, 922: terminal, 930: housing, 930a: housing, 930b: housing, 9 31: negative electrode, 932: positive electrode, 933: separator, 950: wound body, 951: terminal, 95 2: terminal, 980: secondary battery, 981: film, 982: film, 993: wound body, 994: negative electrode, 995: positive electrode, 996: separator, 997: lead electrode, 998: lead electrode, 7100: portable display device, 7101: housing, 7102: display unit, 7103: operation Button, 7104: Secondary battery, 7200: Portable information terminal, 7201: Housing, 7202: Surface Display unit, 7203: Band, 7204: Buckle, 7205: Operation button, 7206: Input / output Input terminal, 7207: icon, 7300: display device, 7304: display unit, 7400: mobile phone Telephone, 7401: Housing, 7402: Display, 7403: Operation buttons, 7404: External connection port, 7405: speaker, 7406: microphone, 7407: secondary battery, 8000: table Display device, 8001: housing, 8002: display unit, 8003: speaker unit, 8004: secondary battery Battery, 8021: Charging device, 8022: Cable, 8024: Secondary battery, 8100: Lighting equipment Placement, 8101: Housing, 8102: Light source, 8103: Secondary battery, 8104: Ceiling, 8105 : Side wall, 8106: Floor, 8107: Window, 8200: Indoor unit, 8201: Housing, 8202: Air outlet, 8203: Secondary battery, 8204: Outdoor unit, 8300: Electric refrigerator-freezer, 8301 : Housing, 8302: Refrigerator door, 8303: Freezer door, 8304: Secondary battery, 8400 :Automobile, 8401:Headlight, 8406:Electric motor, 8500:Automobile, 86 00: Scooter, 8601: Side mirror, 8602: Secondary battery, 8603: Turn signal light , 8604: Under-seat storage, 9600: Tablet terminal, 9625: Switch, 9626 : Switch, 9627: Power switch, 9628: Operation switch, 9629: Fastener, 9 630: Housing, 9630a: Housing, 9630b: Housing, 9631: Display unit, 9633: Thick Solar cell, 9634: Charge / discharge control circuit, 9635: Power storage body, 9636: DCDC converter , 9637: Converter, 9640: Moving parts

Claims

1. forming a first mixture having a fluorine source and a magnesium source; a first container containing the first mixture and the lithium cobalt oxide is covered with a lid, and then the first container is placed in a heating furnace; After the inside of the heating furnace is made into an oxygen-containing atmosphere, the inside of the heating furnace is heated to form a composite oxide; a method for preparing a positive electrode active material, the method comprising heating a second mixture containing the composite oxide, a nickel source, and an aluminum source, the second mixture is heated to a temperature lower than a temperature at which the interior of the heating furnace is heated.

2. forming a first mixture having a fluorine source and a magnesium source; a first container containing the first mixture and the lithium cobalt oxide is covered with a lid, and then the first container is placed in a heating furnace; the inside of the heating furnace is evacuated, oxygen gas is introduced, and then the inside of the heating furnace is heated to form a composite oxide; a method for preparing a positive electrode active material, the method comprising heating a second mixture containing the composite oxide, a nickel source, and an aluminum source, the second mixture is heated to a temperature lower than a temperature at which the interior of the heating furnace is heated.

3. placing a lid on a first container containing a first mixture having lithium cobalt oxide, a fluorine source, and a magnesium source in a furnace; After the inside of the heating furnace is made into an oxygen-containing atmosphere, the inside of the heating furnace is heated to form a composite oxide; a method for preparing a positive electrode active material, the method comprising heating a second mixture containing the composite oxide, a nickel source, and an aluminum source, the second mixture is heated to a temperature lower than a temperature at which the interior of the heating furnace is heated.

4. placing a lid on a first container containing a first mixture having lithium cobalt oxide, a fluorine source, and a magnesium source in a furnace; the inside of the heating furnace is evacuated, oxygen gas is introduced, and then the inside of the heating furnace is heated to form a composite oxide; a method for preparing a positive electrode active material, the method comprising heating a second mixture containing the composite oxide, a nickel source, and an aluminum source, the second mixture is heated to a temperature lower than a temperature at which the interior of the heating furnace is heated.

5. forming a first mixture having lithium fluoride and magnesium fluoride; a first container containing the first mixture and the lithium cobalt oxide is covered with a lid, and then the first container is placed in a heating furnace; After the inside of the heating furnace is made into an oxygen-containing atmosphere, the inside of the heating furnace is heated to form a composite oxide; a method for preparing a positive electrode active material, the method comprising heating a second mixture containing the composite oxide, a nickel source, and an aluminum source, the second mixture is heated to a temperature lower than a temperature at which the interior of the heating furnace is heated.

6. forming a first mixture having lithium fluoride and magnesium fluoride; a first container containing the first mixture and the lithium cobalt oxide is covered with a lid, and then the first container is placed in a heating furnace; the inside of the heating furnace is evacuated, oxygen gas is introduced, and then the inside of the heating furnace is heated to form a composite oxide; a method for preparing a positive electrode active material, the method comprising heating a second mixture containing the composite oxide, a nickel source, and an aluminum source, the second mixture is heated to a temperature lower than a temperature at which the interior of the heating furnace is heated.

7. placing a lid on a first container containing a first mixture having lithium cobalt oxide, lithium fluoride, and magnesium fluoride, and then placing the first container in a furnace; After the inside of the heating furnace is made into an oxygen-containing atmosphere, the inside of the heating furnace is heated to form a composite oxide; a method for preparing a positive electrode active material, the method comprising heating a second mixture containing the composite oxide, a nickel source, and an aluminum source, the second mixture is heated to a temperature lower than a temperature at which the interior of the heating furnace is heated.

8. placing a lid on a first container containing a first mixture having lithium cobalt oxide, lithium fluoride, and magnesium fluoride, and then placing the first container in a furnace; the inside of the heating furnace is evacuated, oxygen gas is introduced, and then the inside of the heating furnace is heated to form a composite oxide; a method for preparing a positive electrode active material, the method comprising heating a second mixture containing the composite oxide, a nickel source, and an aluminum source, the second mixture is heated to a temperature lower than a temperature at which the interior of the heating furnace is heated.

9. 9. The method for producing a positive electrode active material according to claim 1, wherein the inside of the heating furnace is heated to 735°C or more and 1000°C or less.

Images