Lithium-ion rechargeable battery

Abstract

To provide a lithium ion secondary battery that achieves high energy density by increasing the amount of lithium ions per volume and / or per weight of particles having a positive electrode active material.SOLUTION: A particle has a first region, a second region in contact with at least a portion of the surface of the first region and located outside the first region, and a third region in contact with at least a portion of the surface of the second region and located outside the second region, and the first region and the second region contain lithium and oxygen, at least one of the first region and the second region contains manganese, and at least one of the first region and the second region contains an element represented by M, the first region has first crystals with a layered rock salt structure, and the second region has second crystals with a layered rock salt structure, and the orientation of the first crystals and the orientation of the second crystals are different.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This invention relates to a product, method, or method of manufacture. Or, this invention relates to a process, machine , relating to manufacture or composition of matter. In particular One aspect of the present invention relates to a semiconductor device, a display device, a light-emitting device, an imaging device, an energy storage device, and a memory device. The present invention relates to methods for driving them, or methods for manufacturing them. In particular, one aspect of the present invention relates to energy storage This relates to the structure of the device and its manufacturing method, particularly concerning the positive electrode active material of lithium-ion secondary batteries. ru. [Background technology]

[0002] In recent years, portable electronic devices such as smartphones and tablets have become widespread. Also, Due to growing concern about environmental issues, attention has been drawn to hybrid cars and electric vehicles, and The importance of energy storage devices, including secondary batteries, is increasing. Nickel-metal hydride batteries are one example of secondary batteries. Examples include batteries, lead-acid batteries, and lithium-ion rechargeable batteries. Among them, lithium-ion Because secondary batteries offer high capacity and miniaturization, development is progressing rapidly.

[0003] The basic structure of a secondary battery is one in which an electrolyte is interposed between the positive electrode and the negative electrode. Examples of materials possessing substance include solid electrolytes and electrolyte solutions. The positive and negative electrodes are as follows: Typical configurations include a current collector and an active material layer provided on the current collector. In the case of lithium-ion secondary batteries, a material capable of intercalating and releasing lithium is used as the positive electrode. It is also used as the active material for the negative electrode.

[0004] In a lithium-ion secondary battery, as the positive electrode active material, for example, as shown in Patent Document 1 Lithium iron phosphate (LiFePO4), lithium manganese phosphate (LiMnPO4) ), lithium cobalt phosphate (LiCoPO4), lithium nickel phosphate (LiNiP Lithium (Li) and iron (Fe), manganese (Mn), and cobalt (Co), such as O4. Other known examples include phosphate compounds having an olivine structure containing nickel (Ni). [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 11-25983 [Overview of the project] [Problems that the invention aims to solve]

[0006] One aspect of the present invention is to increase the capacity per unit volume and / or per unit weight of an energy storage device. One of the challenges is to address the following. Furthermore, one aspect of the present invention relates to the volume of the electrode, or / or the weight One of the challenges is to increase the capacity per unit volume.

[0007] Alternatively, one aspect of the present invention relates to the amount per volume of particles having a positive electrode active material, or / or by weight One of the challenges is to increase the capacity per unit volume. Alternatively, one aspect of the present invention relates to a positive electrode active material. To increase the amount of lithium ions per unit volume and / or per unit weight of particles having One of the challenges is to achieve a high energy density.

[0008] Alternatively, in one aspect of the present invention, in a positive electrode having a positive electrode active material, the battery reaction is at a higher potential. One of the challenges is to ensure stable response.

[0009] Alternatively, one aspect of the present invention provides an energy storage device in which capacity degradation during charge-discharge cycles is suppressed. One of the objectives is to provide a positive electrode that can be manufactured at low cost. Alternatively, one aspect of the present invention is a positive electrode that can be manufactured at low cost. One of our objectives is to provide active materials.

[0010] Furthermore, high ionic conductivity and electrical conductivity are desirable for use as positive electrode active materials in lithium-ion secondary batteries. It is desirable that... Therefore, one aspect of the present invention relates to ionic conductivity and / or electrical conductivity One of our challenges is to provide a positive electrode active material with high performance.

[0011] Alternatively, one aspect of the present invention aims to provide a method for manufacturing electrodes for an energy storage device. Alternatively, one aspect of the present invention aims to provide a method for producing a positive electrode active material for a secondary battery. It shall be one of them.

[0012] Alternatively, one aspect of the present invention aims to provide a novel substance. One aspect of the invention aims to provide a novel positive electrode active material. One embodiment aims to provide novel particles having a positive electrode active material. One aspect of the invention aims to provide a novel energy storage device. Or, one aspect of the present invention One aspect of this invention aims to provide a novel battery. Alternatively, one aspect of this invention aims to provide a novel battery. One of the objectives is to provide a lithium-ion secondary battery.

[0013] Furthermore, the description of these problems does not preclude the existence of other problems. One approach does not necessarily need to solve all of these problems. The title will become clear from the description in the specification, drawings, claims, etc. It is possible to extract other issues from the descriptions in the drawings, claims, etc. [Means for solving the problem]

[0014] One aspect of the present invention is a particle having a lithium manganese composite oxide.

[0015] In one aspect of the present invention, particles having a lithium manganese composite oxide are in a first region and It has a second region. Furthermore, according to one aspect of the present invention, it has a lithium manganese composite oxide. The particles preferably have a third region.

[0016] The second region is in contact with at least a portion of the surface of the first region and is located outside the first region. Here, "outside" refers to the area closer to the surface of the particle. The third region is the second region. It is preferable that it is in contact with at least a portion of the surface and located outside the second region.

[0017] The particles according to one aspect of the present invention have a second region, thereby enabling the particles according to one aspect of the present invention to store energy. When used as the positive electrode active material in a pond, it may be possible to improve the discharge capacity. In some cases, it is possible to increase the discharge voltage.

[0018] The particles according to one aspect of the present invention have a third region, thereby enabling the particles according to one aspect of the present invention to store energy. When used as the positive electrode active material in a pond, it may be possible to improve the discharge capacity. In some cases, it is possible to increase the discharge voltage.

[0019] The first region and the second region contain lithium and oxygen. At least one of the first and second regions contains manganese. At least one of the regions contains element M, where element M is lithium, manganese It is preferably a metal element other than those listed above, or silicon, phosphorus, Ni, Ga, Fe, Mo Gold selected from In, Nb, Nd, Co, Sm, Mg, Al, Ti, Cu, or Zn. It is more preferably one of the group elements, Si, or P, and more preferably nickel. It is preferable.

[0020] Furthermore, the first and second regions may contain both manganese and element M. More preferable.

[0021] Furthermore, the third region is a particle having lithium manganese composite oxide, which is one embodiment of the present invention. It is preferable that the surface is included.

[0022] One aspect of the present invention is a power storage device using particles having lithium manganese composite oxide. When fabricated, the third region is in relation to the battery reaction, such as charging and discharging, compared to the first region and the third region. It is preferable that it be more stable compared to region 2.

[0023] Here, the second region may have a different crystal structure from the first region. Or, the second region The region may have crystals oriented in a different direction from the first region. Here, different directions are each This refers to a difference in the orientation of the crystals, for example, at an angle greater than 10°.

[0024] For example, the second region has a spinel-type structure, and the first region has a layered salt-type structure. It is preferable that the second region has a spinel-type structure, in one aspect of the present invention When particles are used as the positive electrode active material of a storage battery, the discharge capacity can be improved. There are also cases where the discharge voltage can be increased.

[0025] Furthermore, it is preferable that the second region has a different composition from the first region.

[0026] Furthermore, the manganese in the second region has a different valence than the manganese in the first region. This is also acceptable. Furthermore, the element M in the second region has a different valence than the element M in the first region. You may have it.

[0027] Furthermore, a transition layer may be provided between the second region and the first region. Or, the second region A mixed layer may be present between the first region and the first region.

[0028] One aspect of the present invention is a particle having a lithium manganese composite oxide, wherein the first region and It has a second region, the second region adjoins at least a part of the first region, and the first region The first and second regions have lithium and oxygen, and less than the first or second region Both regions contain manganese, and at least one of the first or second region is represented by M. It has the element, the first region has a first crystal which is a layered rock salt type structure, and the second region is It has a second crystal with a layered rock salt structure, and the {0 0 1} face of the first crystal is the second The crystal has fewer {1 0 0} faces, {1 3 -1} faces, or {-1 3 1} faces. It is a particle that is at least one parallel to one of the planes. Here, two planes being parallel means, for example, two planes The angle of the normal is 10° or less, more preferably 5° or less, and even more preferably 3° or less. This means that two lines are parallel, for example, the angle between the two lines is 10° or less, or more preferably... "K" means 5° or less, and more preferably 3° or less.

[0029] Alternatively, one aspect of the present invention is a particle having a lithium manganese composite oxide, and the first It has a first region, a second region, and a third region, the second region being at least a part of the first region. The third region is adjacent to at least a portion of the second region, and the first region and the second region The region has lithium and oxygen, and at least one of the first region or the second region is It contains manganese, and at least one of the first or second region contains an element represented by M. The first region has a layered rock salt structure, and the second region has a layered rock salt structure. It has a second crystal structure, and the orientation of the first crystal and the orientation of the second crystal are different for the particles. Yes. The third region preferably contains carbon.

[0030] Furthermore, in the above configuration, the {0 0 1} plane of the first crystal is the same as the plane of the second crystal at least one of the {1 0 0} face, {1 3 -1} face, or {-1 3 1} face. It is preferable that it be parallel to the line.

[0031] Alternatively, one aspect of the present invention is a particle having a lithium manganese composite oxide, and the first It has a first region and a second region, the second region being adjacent to at least a part of the first region, and the first The first region and the second region have lithium and oxygen, and the first region or the second region At least one of them has manganese, and at least one of the first region or the second region is It has an element represented by M, and the first region has a first crystal which has a layered rock salt structure, and the second The region in question contains particles with a second crystal structure, which is a spinel-type structure.

[0032] Alternatively, one aspect of the present invention is a particle having a lithium manganese composite oxide, and the first It has a first region and a second region, the second region being adjacent to at least a part of the first region, and the first The first region and the second region have lithium and oxygen, and the first region or the second region At least one of them has manganese, and at least one of the first region or the second region is It has an element represented by M, and the first region contains lithium, manganese, element M, and oxygen. The ratio of atoms is expressed as a1:b1:c1:d1, and in the second region, lithium, manganese, element M, The atomic ratio of oxygen is given by a2:b2:c2:d2, where d1÷(b1+c1)(=A (Let's call it 1) is 2.2 or greater, and d2÷(b2+c2)(=A2) is less than 2.2. It is a certain particle. Thus, because A2 is smaller than A1, one aspect of the present invention When these particles are used as the positive electrode active material of a storage battery, the stability for charging and discharging in the second region is In some cases, the performance can be increased beyond the first region. Furthermore, the particles of one embodiment of the present invention can be used to store energy. When used as the positive electrode active material in a pond, it may be possible to improve the discharge capacity. In some cases, it is possible to increase the discharge voltage.

[0033] Furthermore, in the above configuration, there is a third region that is in contact with at least a part of the second region. Preferably, the third region has carbon.

[0034] Furthermore, in the above configuration, the thickness of the third region is 0.1 nm or more and 30 nm or less. It is preferable.

[0035] Alternatively, one aspect of the present invention is a particle having a lithium manganese composite oxide, and the first It has a first region and a second region, the second region being adjacent to at least a part of the first region, and the first The first region and the second region consist of lithium, manganese, the element represented by M, oxygen, and The atomic ratio of lithium, manganese, element M, and oxygen in the first region is a1:b1: Represented as c1:d1, this is the atomic ratio of lithium, manganese, element M, and oxygen in the second region. It is expressed as a2:b2:c2:d2, and d1÷(b1+c1) is 2.2 or greater, and d2÷ (b2+c2) is less than 2.2, and the first region has a first crystal with a layered rock-salt structure. Furthermore, the second region has a second crystal which is a layered rock salt structure, and the first crystal has {0 0 The {1} plane is the {1 0 0} plane, {1 3 -1} plane, or {-1} plane of the second crystal. 3. It is a particle parallel to at least one of the 1} planes.

[0036] Furthermore, in the above configuration, the second region has a layered region, and the thickness of the layered region is 0.1 It is preferable that the wavelength is between 30 nm and 30 nm.

[0037] Alternatively, one aspect of the present invention is a secondary battery using a positive electrode having the particles described above. Alternatively, one aspect of the present invention is an electronic device equipped with the secondary battery.

[0038] Here, according to one aspect of the present invention, using particles having lithium manganese composite oxide, When an electrical device is manufactured, the amount of lithium contained in the particles is affected by battery reactions, such as charging and discharging. The particles change. For example, when charging, lithium is released as lithium ions, and the particles change. The amount of lithium in the battery decreases, and the amount of decrease varies depending on the depth of charging.

[0039] One aspect of the present invention involves mixing particles, a binder, and a solvent to produce a mixture, and the particles It contains lithium, manganese, element M, and oxygen, and element M is chromium, cobalt, and Aluminum, nickel, iron, magnesium, molybdenum, zinc, indium, gallium, One or more elements selected from copper, titanium, niobium, silicon, and phosphorus, and a mixture A mixture layer is created by placing it on a current collector, and then the mixture layer is subjected to heat treatment to create an electrode layer. The electrode layer is composed of at least one of lithium, manganese, element M, and oxygen, and Method for producing an electrode layer having a compound having a bond with at least one element present in the inder. This is the law. Furthermore, in the above configuration, the compound is lithium, manganese, or a small amount of element M. Preferably, the particles contain at least one of the following: fluorine. Also, the particles contain lithium, It is preferable that the oxide contains manganese, element M, and oxygen.

[0040] Alternatively, one aspect of the present invention is an electrode layer provided on a current collector, wherein the electrode layer comprises particles and It has a binder and a solvent, and the particles contain lithium, manganese, element M, and oxygen. And element M is chromium, cobalt, aluminum, nickel, iron, magnesium, molybdenum Select from den, zinc, indium, gallium, copper, titanium, niobium, silicon, and phosphorus. It is one or more elements, and the electrode layer contains lithium, manganese, element M, and a small amount of oxygen. A compound having a bond between at least one of the elements of the binder and at least one element of the binder. The electrode layer has the following properties. In addition, in the above configuration, the compound is lithium, manganese, and It is preferable that the particles have at least one of the elements M and fluorine. Preferably, the oxide contains lithium, manganese, element M, and oxygen.

[0041] Here, according to one aspect of the present invention, using particles having lithium manganese composite oxide, When an electrical device is manufactured, the amount of lithium contained in the particles is affected by battery reactions, such as charging and discharging. The particles change. For example, when charging, lithium is released as lithium ions, and the particles change. The amount of lithium in the battery decreases, and the amount of decrease varies depending on the depth of charging. [Effects of the Invention]

[0042] According to one aspect of the present invention, the capacity per unit volume and / or per unit weight of an energy storage device is increased. It is possible to do so. Furthermore, according to one aspect of the present invention, per unit volume of the electrode, or / or weight It is possible to increase the volume per unit amount.

[0043] Furthermore, according to one aspect of the present invention, per unit volume of particles having a positive electrode active material, or / and The capacity per unit weight can be increased. Furthermore, according to one aspect of the present invention, the positive electrode active material is This increases the amount of lithium ions per unit volume and / or weight of the particles, and high This makes it possible to achieve high energy density.

[0044] Furthermore, according to one aspect of the present invention, in a positive electrode having a positive electrode active material, a battery is formed at a higher potential. The reaction can be carried out stably.

[0045] Furthermore, according to one aspect of the present invention, an energy storage device in which capacity degradation during charge-discharge cycles is suppressed. Furthermore, according to one aspect of the present invention, a positive electrode active material can be manufactured at low cost. We can provide quality.

[0046] Furthermore, as a required characteristic for the positive electrode active material of a lithium-ion secondary battery, ion conductivity High ionic conductivity and electrical conductivity are desirable. According to one aspect of the present invention, ionic conductivity and Alternatively, it is possible to provide a positive electrode active material with high electrical conductivity.

[0047] Furthermore, according to one aspect of the present invention, a method for manufacturing electrodes for an energy storage device can be provided. According to one aspect of the present invention, a method for producing a positive electrode active material for a secondary battery can be provided.

[0048] Furthermore, according to one aspect of the present invention, a novel substance can be provided. Depending on the embodiment, a novel positive electrode active material can be provided. Furthermore, according to one embodiment of the present invention, Novel particles having a positive electrode active material can be provided. Furthermore, according to one aspect of the present invention, A novel energy storage device can be provided. Furthermore, according to one aspect of the present invention, a novel battery can be provided. It can be provided. Furthermore, according to one aspect of the present invention, a novel lithium-ion secondary battery can be provided. It can be provided.

[0049] Furthermore, the description of these effects does not preclude the existence of other effects. One embodiment does not necessarily have to possess all of these effects. Furthermore, other effects may be considered. This will become clear from the description in the specification, drawings, claims, etc., and the specification, drawings It is possible to extract effects other than those mentioned above from the descriptions in the surfaces, claims, etc. [Brief explanation of the drawing]

[0050] [Figure 1] A flowchart illustrating the method for producing the active material. [Figure 2] A diagram showing particles according to one embodiment of the present invention. [Figure 3] A diagram illustrating the crystal structure. [Figure 4] A diagram illustrating the crystal structure. [Figure 5] A schematic diagram showing electrodes. [Figure 6] A diagram illustrating a slim battery. [Figure 7] A diagram illustrating a cross-sectional view of an electrode. [Figure 8] A diagram illustrating a slim battery. [Figure 9] A diagram illustrating a slim battery. [Figure 10] A diagram illustrating a slim battery. [Figure 11] A diagram illustrating the radius of curvature of a surface. [Figure 12] A diagram illustrating the radius of curvature of film. [Figure 13] A diagram illustrating a coin-type rechargeable battery. [Figure 14] A diagram illustrating a cylindrical storage battery. [Figure 15] A diagram illustrating an example of an energy storage device. [Figure 16] A diagram illustrating an example of an energy storage device. [Figure 17] A diagram illustrating an example of an energy storage device. [Figure 18] A diagram illustrating an example of an energy storage device. [Figure 19] A diagram illustrating an example of an energy storage device. [Figure 20] A diagram illustrating an example of an electronic device. [Figure 21] A diagram illustrating an example of an electronic device. [Figure 22] A diagram illustrating an example of an electronic device. [Figure 23] A diagram illustrating an example of an electronic device. [Figure 24] A block diagram illustrating one aspect of the present invention. [Figure 25] A conceptual diagram illustrating one aspect of the present invention. [Figure 26] A circuit diagram illustrating one aspect of the present invention. [Figure 27] A circuit diagram illustrating one aspect of the present invention. [Figure 28] A conceptual diagram illustrating one aspect of the present invention. [Figure 29] A block diagram illustrating one aspect of the present invention. [Figure 30] A flowchart illustrating one aspect of the present invention. [Figure 31] A diagram showing the charge and discharge characteristics. [Figure 32] A diagram illustrating a particle according to one embodiment of the present invention. [Figure 33] A diagram showing the measurement results of EDX. [Figure 34] HAADF-STEM observation results. [Figure 35] A diagram showing electron diffraction. [Figure 36] A diagram showing the charge and discharge characteristics. [Figure 37] Cross-sectional view of the electrode and separator. [Figure 38] A diagram showing the charge and discharge characteristics. [Figure 39] Results of transmission electron microscopy observation. [Figure 40] Results of transmission electron microscopy observation. [Figure 41] A diagram showing electron diffraction. [Figure 42] A diagram showing the particle size distribution. [Figure 43] Scanning electron microscope observation results. [Figure 44] Scanning electron microscope observation results. [Figure 45] A diagram showing the relationship between the number of charge / discharge cycles and discharge capacity. [Figure 46] A diagram showing differential scanning calorimetry curves. [Figure 47] A figure showing the results of EDX measurement. [Figure 48] A figure showing the results of EDX measurement. [Figure 49] A figure showing the results of EDX measurement. [Figure 50] A figure showing the results of EDX measurement. [Figure 51] A figure showing the results of EDX measurement. [Figure 52] A diagram showing the charge and discharge characteristics. [Figure 53] A figure showing the measurement results of XPS. [Figure 54] A figure showing the measurement results of XPS. [Figure 55] A diagram showing the charge and discharge characteristics. [Modes for carrying out the invention]

[0051] The embodiments of the present invention will be described in detail below with reference to the drawings. However, the present invention This is not limited to the description below, and its form and details can be changed in various ways, as is the case for those skilled in the art. This will be easily understood. Furthermore, the present invention shall be interpreted as being limited to the contents of the embodiments described below. It is not meant to be done. Furthermore, when explaining the structure of the invention using drawings, the same thing is referred to The symbol "su" is used consistently across different drawings. Note that when referring to similar items, the hatch pattern is used. The same character is used, and sometimes no special symbol is assigned to it.

[0052] Note that in the diagram, the size, thickness of the film (layer), or area may be exaggerated for clarity. There are cases where this is the case.

[0053] Note that the ordinal numbers "1st" and "2nd" are used for convenience only and do not necessarily indicate the order of the processes or the number of steps. This does not indicate a hierarchical order. Therefore, for example, "the first" could be "the second" or "the third." It can be explained by substituting it as appropriate. Also, the ordinal numbers and The ordinal numbers used to specify one aspect of the present invention may not always coincide.

[0054] Note that the term "active material" refers only to the substance involved in the insertion and removal of ions, which are carriers. The specification may include a layer that coats the "active material".

[0055] (Embodiment 1) In this embodiment, "particles having lithium manganese composite oxide" is one aspect of the present invention. This section will explain the "[specific term]". Furthermore, the electrode containing the particles will also be explained.

[0056] A lithium manganese composite oxide according to one aspect of the present invention has the compositional formula Li a Mn b M c O d Represented by This is possible. Here, element M is a metallic element selected from among lithium and manganese, It is preferable to use silicon or phosphorus. Also, 0 ≤ a / (b+c) < 2 and c > 0 It is preferable that the following conditions are met: and 0.26 ≤ (b+c) / d < 0.5. A complex oxide is an oxide containing at least lithium and manganese, as well as chromium and corn. Bals, aluminum, nickel, iron, magnesium, molybdenum, zinc, indium, A small number of elements selected from the group consisting of gallium, copper, titanium, niobium, silicon, and phosphorus. It may contain at least one element. Furthermore, lithium manganese composite oxide is found in layered rock salt. It is preferable that the crystalline structure is of a certain type. Furthermore, lithium manganese composite oxide is It may also have a layered rock salt type crystal structure and a spinel type crystal structure. Lithium manganese composite oxides, for example, have an average primary particle diameter of 5 nm to 50 μm. It is preferable that this be the case.

[0057] <Synthesis> Next, a method for producing "particles having lithium manganese composite oxide" according to one aspect of the present invention. This will be explained. In this embodiment, first, a lithium manganese composite oxide is synthesized. Subsequently, a coating layer is formed on the lithium manganese composite oxide, and the first region, the second region and A particle having a third region is obtained.

[0058] The raw materials for lithium manganese composite oxides are manganese compounds and lithium compounds. It can be used. In addition, chromium can be used together with the raw materials for manganese compounds and lithium compounds. Cobalt, aluminum, nickel, iron, magnesium, molybdenum, zinc, indigo Selected from the group consisting of um, gallium, copper, titanium, niobium, silicon, and phosphorus. A raw material for a compound containing at least one element can be used. As a manganese compound... Examples include manganese dioxide, manganese trioxide, manganese tetraoxide, and hydrated manganese oxide. Lithium compounds such as manganese carbonate and manganese nitrate can be used. For example, lithium hydroxide, lithium carbonate, lithium nitrate, etc., can be used. .

[0059] In this embodiment, MnCO3 is used as the manganese compound and Li2C is used as the lithium compound. O3 and NiO are used as starting materials.

[0060] First, as shown in step S11 of Figure 1, Li2CO3 and Mn are used as starting materials. CO3 and NiO are used, and each is weighed separately.

[0061] For example, when using Li2CO3, MnCO3, and NiO as starting materials, the weighing If the ratio (molar ratio) is Li2CO3:MnCO3:NiO = 1:0.7:0.3, then As the final product, lithium manganese composite oxide, Li2Mn 0.7 Ni 0.3 O3 It will be manufactured. In this case, the atomic ratio of lithium manganese composite oxide is Li:( The ratio of Mn + Ni becomes 2:1.

[0062] In this embodiment, the atomic ratio of the lithium manganese composite oxide is Li:(Mn+Ni)= Adjust the ratio (molar ratio) of the starting materials so that it deviates from 2:1.

[0063] In this embodiment, the ratio (molar ratio) of the starting materials is Li2CO3:MnCO3:N Weigh the materials so that iO = 0.84:0.8062:0.318.

[0064] Next, as shown in step S12 of Figure 1, Li2CO3, MnCO3, and NiO Mix the following. There are no particular restrictions on the method of mixing the starting materials; known crushers or pulverizers can be used. They can be used in various ways, such as ball mills, bead mills, jet mills, and roller mills. These include the following. Furthermore, the crushing and grinding method may be dry or wet. There are no particular restrictions on the solvents that can be used; for example, water, alcohol, acetone, etc. You can use these.

[0065] When mixing the starting materials using a wet process, as shown in step S13 of Figure 1, A heat treatment is performed to evaporate the solvent contained in the mixed starting materials. The process should be carried out at a temperature between 50°C and 150°C. By performing the heat treatment, the mixed The solvent contained in the starting materials is evaporated to obtain the mixed materials.

[0066] Next, as shown in step S14 of Figure 1, the mixed raw materials are placed in the crucible and heated to over 800°C for 10 minutes. The firing will be carried out at a temperature of 0°C or below. The firing time will be, for example, 5 hours or more and 20 hours or less, and the firing gas will be used. Use dry air and set the flow rate to 10 L / min. The firing atmosphere may also be an atmospheric atmosphere. Alternatively, an atmosphere using oxygen gas may be used. By firing the mixed raw materials, the fired product can be produced. (Lithium manganese composite oxide) is formed.

[0067] As shown in Figure 2(A), multiple primary particles synthesized by firing are sintered lithium Manganese composite oxides are formed when multiple primary particles are sintered to create larger secondary particles. Therefore, as shown in step S15 of Figure 1, multiple primary particles are sintered into lithium The ummanganese complex oxide is subjected to a crushing treatment. By performing the crushing treatment on the calcined material... The calcined material is crushed into primary particles, or into a powder that is close to primary particles. The disintegration process also includes operations in which the sintered material is crushed. Crushing refers to further crushing the primary particles. This refers to the operation. The crushing process is carried out using known crushers and pulverizers, similar to the mixing method of the starting materials. It is possible to do so. For example, a ball mill or a bead mill can be used. Also, The crushing and grinding method may be dry or wet. There are no particular restrictions on the medium used; for example, water, alcohol, acetone, etc., can be used. ru.

[0068] Here, the size of the particles after crushing and grinding can be measured, for example, by measuring the specific surface area of ​​the particles. It can be evaluated by determining the ratio of particles having lithium manganese composite oxide. By increasing the surface area, particles containing lithium manganese composite oxide are used as the positive electrode. When manufacturing a rechargeable battery, for example, it is possible to increase the contact area between the particles and the electrolyte. By increasing the contact area with the dissolution solution, the reaction rate of the battery can be increased, for example, It is possible to improve the force characteristics.

[0069] The crushing process may increase the specific surface area of ​​the particles, which is preferable. The specific surface area of ​​particles containing manganese composite oxide is, for example, 0.1 m². 2 A value of / g or more is preferable. Furthermore, if the specific surface area of ​​the particles becomes too large, the electrodes made using these particles will have a surface area that is too small. In some cases, the amount of binder may be insufficient relative to the area, which may result in a decrease in strength. Increasing the amount of indium may reduce the capacity of the electrode per unit weight and per unit volume. Therefore, the specific surface area of the particles having the lithium manganese composite oxide is, for example, 1 m 2 / g or more and 50 m 2 / g or less is preferable, and 5 m 2 / g or more and 30 m 2 / g or less is more preferable.

[0070] In this embodiment, the pulverization treatment of the sintered lithium manganese composite oxide of primary particles is performed by a wet method using acetone with a bead mill. When performing the pulverization treatment, when performing it wet, a heat treatment for evaporating the solvent after the pulverization treatment is performed. The heat treatment performed here may be performed in the same manner as in step S13. Thereafter, by performing vacuum drying, a powdery lithium manganese composite oxide is obtained.

[0071]

[0072] Next, a heat treatment is performed. As shown in step S16 of FIG. 1, the heat treatment is performed by putting the lithium manganese composite oxide after the pulverization treatment in a crucible and heating it at 300° C. or higher and 1000° C. or lower, preferably 600° C. or higher and 900° C. or lower. The heating time is, for example, 5 hours or more and 20 hours or less, dry air is used as the gas, and the flow rate is 10 L / min. The heating atmosphere may be an air atmosphere or an atmosphere using oxygen gas.

[0072] U By the above steps, a lithium manganese composite oxide represented by the composition formula Li a Mn b M c O d

[0073]

[0074] By setting i2CO3:MnCO3:NiO = 0.84:0.8062:0.318 Li, the composition formula 1.68 Mn 0.8062 M 0.318 Lithium manganese represented as O3 It is possible to form a complex oxide.

[0074] Furthermore, the lithium manganese composite oxide after the decomposition treatment shown in step S15 is The impact during crushing may cause crystalline disorder. Also, lithium manganese complex acid Oxygen deficiency may occur in the phosphate. Therefore, the powdered lithium phosphate after vacuum drying It is preferable to perform a heat treatment on the gangan complex oxide again.

[0075] By performing heat treatment on the lithium manganese composite oxide after crushing, oxygen deficiencies are repaired. Furthermore, it is possible to restore the crystalline disorder that occurred during the crushing process. The powdered lithium manganese composite oxide after processing can be subjected to crushing treatment again. In this case, the crushing process can be carried out using the same method as in step S15 of Figure 1. .

[0076] Here, Li2CO3:MnCO3:NiO = 0.84:0.8062:0.318 Using the raw materials, lithium manganese composite oxide is produced following steps S11 to S16 shown in Figure 1. A sample was fabricated and its temperature stability was evaluated. Specifically, the evaluation was performed using differential scanning calorimetry. Figure 46 shows the differential scanning calorific value (DSC) curve. The vertical axis represents heat flow, and the horizontal axis represents temperature. Figure 4 As shown in 6, a peak indicating exothermic reaction was observed at 262.2°C. In this case, it was stable in DSC evaluation. Therefore, one embodiment of the present invention of lithium man The gunn complex oxide is found to be stable even at high temperatures below 260°C.

[0077] The lithium manganese composite oxide shown in this embodiment has an atomic ratio of Li:(Mn+Ni) It is being adjusted so that it deviates from 2:1. Therefore, the atomic ratio is Li:(Mn+Ni)= Compared to the case where a lithium manganese composite oxide with a 2:1 ratio is used as the electrode, the voltage increases. The discharge capacity also increases.

[0078] Through the above process, particulate lithium manganese composite oxide can be obtained. Preferably, the lithium manganese composite oxide has a first region and a second region. The second region is in contact with at least a portion of the surface of the first region and is outside the first region. It is located. Here, "outside" refers to being closer to the surface of the particle.

[0079] The first region and the second region contain lithium and oxygen. At least one of the first and second regions contains manganese. At least one of the regions contains element M, where element M is lithium, manganese It is preferably a metal element other than those listed above, or silicon, phosphorus, Ni, Ga, Fe, Mo Gold selected from In, Nb, Nd, Co, Sm, Mg, Al, Ti, Cu, or Zn. It is more preferably one of the group elements, Si, or P, and more preferably nickel. It is preferable.

[0080] <Coating layer> Next, a coating layer is provided on the resulting lithium manganese composite oxide. The coating layer contains carbon. It is preferable to use carbon-coated particles as electrodes in a battery because carbon has high conductivity. This allows for, for example, lowering the resistance of the electrodes. Furthermore, the coating layer has an oxide graphite coating. It may contain graphene, or it may contain reduced graphene oxide.

[0081] Alternatively, the coating layer may contain a metal compound. Here, the metal may be, for example, cobalt. Examples include aluminum, nickel, iron, manganese, titanium, zinc, lithium, and carbon. As an example of a metal compound, the coating layer contains oxides or fluorides of these metals. That's good too.

[0082] In this embodiment, a layer containing carbon is provided as the coating layer. It is preferable to use graphene. Graphene has excellent electrical properties, including high conductivity. It possesses excellent physical properties, including high flexibility, high mechanical strength, and other desirable characteristics.

[0083] In this specification, graphene refers to single-layer graphene or graphene with 2 to 100 layers. It includes multilayer graphene with a single layer of graphene below. A single layer of graphene is a layer containing π bonds. It refers to a sheet of carbon molecules consisting of one atomic layer. Furthermore, graphene oxide is a type of graphene. This refers to a compound in which graphene has been oxidized. Furthermore, graphene is formed by reducing graphene oxide. In this case, not all of the oxygen contained in graphene oxide is removed, and some of the oxygen remains in the graphene. It remains in the graphene. If graphene contains oxygen, the proportion of oxygen is determined by X-ray photoelectron spectroscopy (XP When measured using S), the total amount of graphene is between 2 atomic% and 20 atomic%, Preferably, the atomic content is between 3% and 15%.

[0084] The thickness of the carbon-containing layer is preferably between 1 nm and 50 nm.

[0085] Next, a method for providing a carbon-containing layer in a lithium manganese composite oxide will be described. In this embodiment, the carbon-containing layer is graphene oxide. Graphene obtained by reducing (abbreviated as GO) Aphene oxide (abbreviated as RGO) is used.

[0086] Graphene oxide is produced using the Hummers method, the Modified Hummers method, or the Black It can be produced using various synthesis methods, such as the oxidation of lead compounds.

[0087] For example, the Hummers process oxidizes graphite such as flaky graphite, This is a method for forming graphite. The formed graphite oxide is graphite and Through oxidation at various points, functional groups such as carbonyl groups, carboxyl groups, and hydroxyl groups are formed. This is a bonded structure where the crystallinity of graphite is impaired and the distance between layers increases. Therefore, the interlayers can be easily separated by ultrasonic treatment, etc., to obtain graphene oxide. can.

[0088] Furthermore, the length of one side of graphene oxide (also called flake size) is 50 nm or more. The flake size is 0 μm or less, preferably 800 nm to 20 μm. This is preferable because it makes it easier to cover the surface of the lithium manganese composite oxide.

[0089] First, graphene oxide and water are placed in a kneader to prepare a dispersion solution of graphene oxide. In this case, the amount of graphene oxide is preferably 0.5 wt% to 5 wt%. If the concentration is less than 5 wt%, it becomes difficult to cover the surface of the lithium manganese composite oxide. Furthermore, if the concentration exceeds 5 wt%, the electrode volume becomes bulky, and the electrode weight increases.

[0090] Next, as shown in step S17 in Figure 1, the lithium manganese complex oxide is added to the dispersion solution. Add the ingredients and knead until stiff. Note that "stiff kneading" refers to mixing with high viscosity. This allows the aggregation of lithium manganese composite oxide powder to be undone, and graph oxide This allows for a more uniform dispersion of the lithium manganese composite oxide.

[0091] Next, the mixture of graphene oxide and lithium manganese composite oxide is subjected to reduced pressure in a bell jar. After drying, the lithium manganese coated with graphene oxide is crushed in a mortar. A composite oxide is obtained.

[0092] Next, as shown in step S18 in Figure 1, on the surface of the lithium manganese composite oxide The coated graphene oxide is subjected to a reduction treatment. The reduction treatment of graphene oxide is performed by heat treatment. You can do it that way, or you can use a reducing agent and carry out the reaction in a solvent. In this embodiment This involves reacting graphene oxide in a solvent using a reducing agent.

[0093] By reacting graphene oxide in a solvent with a reducing agent, lithium manganese The graphene oxide coating on the surface of the composite oxide is reduced, and graphene is formed. Oh, not all of the oxygen contained in graphene oxide is removed; some of the oxygen remains in the graphene. It is acceptable to do so. If graphene contains oxygen, the oxygen content is measured by XPS. In total, 2 to 20 atomic percent of the graphene, preferably 3 atomic percent. The concentration is between 0% and 15atomic%. This reduction treatment is performed at temperatures between room temperature and 150°C. Preferably, the process is carried out at a temperature between room temperature and 80°C. Heating is performed during the reduction treatment. This can accelerate the reduction reaction. Also, the reduction time of graphene oxide It can be between 3 minutes and 10 hours.

[0094] Reducing agents include ascorbic acid, hydrazine, dimethylhydrazine, and hydroquinone. Sodium borohydride (NaBH4), tetrabutylammonium bromide (TBAB ), lithium aluminum hydride (LiAlH4), N,N-diethylhydroxylamine Ascorbic acid and its derivatives can be used. For example, ascorbic acid and hydro Quinones have a weaker reducing power compared to hydrazine and sodium borohydride, making them safer. It is preferable in that it is easy to use for commercial purposes.

[0095] A polar solvent can be used as the solvent, as long as it can dissolve the reducing agent. However, the materials are not limited. For example, water, methanol, ethanol, acetone, tetrahydrogen Lofran (THF), Dimethylformamide (DMF), 1-Methyl-2-pyrrolidone ( NMP) and dimethyl sulfoxide (DMSO), ethylene glycol, diethylene glycol One or more of lycolin or glycerin, or a mixture of two or more, can be used.

[0096] A reducing solution containing a reducing agent and solvent is a mixture of ethanol and ascorbic acid. Alternatively, a solution of water, ascorbic acid, and lithium hydroxide can be used. In this embodiment, when a reducing solution containing ascorbic acid, water, and lithium hydroxide is used... I will explain this.

[0097] The process involves reacting graphene oxide coated with lithium manganese composite oxide in a reducing solution. As a result, graphene oxide undergoes protonation by ascorbic acid. Subsequently, H2 The elimination of oxygen reduces graphene oxide.

[0098] After the reduction treatment, the powder is recovered as shown in step S19 in Figure 1. Here, The reducing solution is filtered. The substance obtained here is called substance A. Suction filtration or similar methods are used for filtration. It is sufficient to leave it as is. Alternatively, substance A and the liquid can be separated using centrifugation.

[0099] Next, the obtained substance A is washed. For washing, for example, the solvent contained in the reducing solution is listed below. It is preferable to use a solvent. Alternatively, the solvent may be the same as the solvent contained in the reducing solution. A different solvent may be used.

[0100] Next, drying is performed. This drying process is, for example, at a temperature of 50°C or higher but less than 500°C, more preferably. This drying process should be carried out at a temperature between 120°C and 400°C for between 1 hour and 48 hours. This process evaporates or removes polar solvents and moisture. In this drying process, oxidation This can accelerate the reduction of rafen. It should be carried out under reduced pressure (vacuum) or a reducing atmosphere. It is also acceptable to do it at atmospheric pressure. Furthermore, air can be used as the atmosphere during drying. Nitrogen or other inert gases may be used.

[0101] Here, if substance A is a particle, it is preferable that the particle forms, for example, secondary particles. stomach.

[0102] Here, when substance A forms secondary particles, the particle size of the secondary particles is, for example, the average value of which is good Preferably 50 μm or less, more preferably 30 μm or less, still more preferably 1 μm or more and 20 μm or less. Here, the particle size refers to the particle size measured using, for example, a particle size distribution meter. Also when substance A forms secondary particles, it may refer to the particle size of the secondary particles. Secondary particles The particle size of can be calculated by observing the particles with a microscope, for example, in addition to the above-mentioned particle size distribution meter. Also, the particle size may be calculated by, for example, calculating the diameter in terms of a circle from the area of the cross section.

[0103] After washing substance A, a solution in which substance A is dispersed in a solvent may be prepared, and spray drying treatment may be performed to dry it. By performing spray drying treatment, substance A may form, for example, secondary particles and the particle size may change.

[0104] Also, it is preferable to perform further heat treatment after the spray drying treatment. For example, at 50 °C or higher and less than 500 °C, more preferably at a temperature of 120 °C or higher and 400 °C or lower, for 1 hour or more and 48 hours or less. By this heat treatment, polar solvents and moisture are evaporated or removed . In this heat treatment step, the reduction of graphene oxide can also be promoted. Also, the heat treatment may be performed under reduced pressure (vacuum) or at atmospheric pressure. Also, it may be performed under a reducing atmosphere 0 Also, as the atmosphere during heating, air may be used, or nitrogen or other inert gases may be used.

[0105] Through the above steps, graphene oxide is reduced, and graphene can be formed on the surface of the lithium manganese composite oxide.

[0106] <00009?19> Note that it is not necessary to desorb all the oxygen contained in graphene oxide, and some oxygen is It may remain in the graphene. If the graphene contains oxygen, the percentage of oxygen is XP When measured in S, the total amount of graphene is between 2 atomic% and 20 atomic%, Preferably, the amount is between 3 atomic% and 15 atomic%.

[0107] By performing heat treatment after reduction treatment, graphene obtained is compared to graphene obtained before heat treatment. In some cases, it may be possible to further increase the electrical conductivity.

[0108] By performing heat treatment after reduction treatment, for example, "lithium manganese" according to one aspect of the present invention In particles having a composite oxide, a first to a third region may be formed. The first to third regions of the "particles having lithium manganese composite oxide" are, It may be formed before heat treatment, or it may be formed during the heat treatment process. For example, the first region formed before the formation of the coating layer, after the formation of the coating layer, and after the reduction treatment. The thickness, composition, and crystal structure of the third region may change during the heat treatment process.

[0109] Furthermore, by performing heat treatment, for example, the elements contained in the binder and lithium manganese can be separated. Particles containing complex oxides may react with other materials. For example, PVd When using F, the fluorine contained in PVdF and the lithium manganese composite oxide are present. The particles consist of lithium, manganese, and one or more of the element M, and the metal fluoride It may form.

[0110] Alternatively, a coating layer of lithium manganese composite oxide, for example, a layer containing carbon, is shown here. However, elements contained in the coating layer and fluorine may form a bond. For example, the coating layer and When using a carbon-containing layer, fluorocarbon may be formed. Here, the coating layer may include a third region possessed by "particles having a lithium manganese composite oxide", and may have the third region and a part of the first region or the second region. Also the second region possessed by "particles having a lithium manganese composite oxide" may, for example, have a part of the coating layer .

[0111] Through the above steps, particles provided with graphene on at least a part of the surface of the lithium manganese composite oxide can be formed.

[0112] Graphene has excellent electrical properties such as high conductivity, and excellent physical properties such as flexibility and high mechanical strength. Therefore, by using an electrode containing the particles in a battery , for example, the electrical conductivity and physical properties of the electrode can be further enhanced.

[0113] Through the above steps, particles of one aspect of the present invention can be obtained. The particles of one aspect of the present invention have a lithium manganese composite oxide. Also, the particles of one aspect of the present invention preferably have a first region to a third region.

[0114] One aspect of the present invention is particles having a lithium manganese composite oxide.

[0115] The particles having a lithium manganese composite oxide, which are one aspect of the present invention, have a first region and a second region. Also, the particles having a lithium manganese composite oxide, which are one aspect of the present invention preferably have a third region.

[0116] The second region is in contact with at least a part of the surface of the first region and is outside the first region​​ It is located. Here, "outside" indicates that it is closer to the surface of the particle. The third region is the second region. It is preferable that it is in contact with at least a portion of the surface of the region and located outside the second region. .

[0117] Furthermore, if the second region has a layered structure, for example, its thickness is 0.1 nm or more and 30 It is preferably less than or equal to nm, and more preferably between 1 nm and 15 nm.

[0118] The first region and the second region contain lithium and oxygen. At least one of the first and second regions contains manganese. At least one of the regions contains element M.

[0119] Furthermore, the first and second regions may contain both manganese and element M. More preferable.

[0120] Furthermore, the third region is a particle having lithium manganese composite oxide, which is one embodiment of the present invention. It is preferable that the surface is included.

[0121] Furthermore, if the third region has a layered structure, for example, its thickness is 0.1 nm or more and 30 Preferably it is less than or equal to nm, more preferably 1 nm to 20 nm, 2 It is even more preferable that the wavelength is between 10 nm and 10 nm.

[0122] Figure 2(A) shows that the particle is located in region 131 as the first region, region 132 as the second region, and An example is shown in which region 133 is the third region.

[0123] As shown in Figure 2(A), region 132 is in contact with at least a portion of the surface of region 131. Furthermore, region 133 is in contact with the surface of region 132, at least in part.

[0124] Furthermore, as shown in Figure 2(B), region 131 has an area that is not covered by region 132. This is also fine. Furthermore, region 132 may have regions that are not covered by region 133. Also, for example, Region 131 may have a region adjacent to region 133. Also, region 131 may have a region adjacent to region 13 It may have regions that are not covered by either region 2 or region 133.

[0125] One aspect of the present invention is a power storage device using particles having lithium manganese composite oxide. When fabricated, the third region is in relation to the battery reaction, such as charging and discharging, compared to the first region and the third region. It is preferable that it be more stable compared to region 2.

[0126] Here, the second region may have a different crystal structure from the first region. Or, the second region The region may have crystals oriented differently from those in the first region.

[0127] For example, the second region has a spinel-type structure, and the first region has a layered salt-type structure. It is preferable to do so.

[0128] Alternatively, for example, the first and second regions have a layered salt rock structure, and the first The first plane of the crystal in the region and the second plane of the crystal in the second region are parallel. This is preferable.

[0129] Here, if the first face is the {0 0 1} face of the layered salt rock structure, then the {0 The {0 1} plane is the {1 0 0} plane and {1 3 -1} plane present in the crystal of the second region. It is preferable that it be parallel to at least one of the planes or the {-1 3 1} plane. If the first face is a {1 0 0} face of a layered salt rock structure, then the {1 0 The {0} plane is the {0 0 1} plane and the {1 3 -1} plane that the crystal possesses in the second region. It is preferable that it is parallel to at least one of the {-1 3 1} planes. Or, the If face 1 is a {1 3 -1} face of a layered salt rock structure, then the {1 3 -1} face of a layered salt rock structure The} plane is the {0 0 1} plane, {1 0 0} plane, or { It is preferable that it is parallel to at least one of the}-1 3 1} planes. Or, the first If the face is a {-1 3 1} face of layered salt rock structure, then the {-1 3 1} face of layered salt rock structure This refers to the {0 0 1} plane, {1 0 0} plane, or {1} plane of the crystal having the second region. It is preferable that it is parallel to at least one of the 3-1 planes.

[0130] Furthermore, for example, the first region and the second region have a layered salt rock structure, and the first region The first orientation of the crystal in the second region is parallel to the second orientation of the crystal in the second region. Preferably, the crystals of the first region and the crystals of the second region are Let me explain directions.

[0131] Here, we have three crystal orientations: <1 0 0>, <1 1 0>, and <-1 1 0>. This will be designated as Group 1. Additionally, <0 0 1>, <0 1 1>, and <0 1 -1> will be designated as Group 2. Let's assume that <-3 2 3>, <3 1 6>, and <6 -1 3> are the third group. Furthermore, <3 2 -3>, <3 -1 6>, and <6 1 3> are designated as the fourth group.

[0132] The crystals in the first region are selected from one of the groups from the first to the fourth group. It has orientation. The crystals in the second region are those in the first to fourth groups that the first region possesses. The orientation of the crystal is selected from one of the three groups other than the selected group. It has a sense of direction.

[0133] The above example of a combination will be explained below with specific examples. Here, (001 The (100) plane and the (100) plane will be explained below. To describe them in detail, the crystal symmetry is... We will use a method of describing indices that are not considered.

[0134] Figure 3 shows the crystal structure of Li2MnO3 viewed from the negative direction of the b-axis. Here, in Figure 3 The region enclosed by the dashed line A contains layers A-1 and A-2, and from the layer A-2 side, layer A-1 Figure 4(A) shows a view of layer A-2 from a direction perpendicular to it. Here, layer A-1 contains oxygen Layer A-2 contains lithium and manganese.

[0135] Furthermore, layers B-1 and B-2, which are located in the area enclosed by the dashed line B shown in Figure 3, are considered to be on the B-2 side. Figure 4(B) shows a view from a direction perpendicular to layers B-1 and B-2.

[0136] In Figure 4(A), lithium or manganese is located on an oxygen atom in the

[0110] direction or The layers are stacked with a shift in the [-100] direction or the [1-10] direction. Similarly, in Figure 4(B) On top of the hexagonal structure formed by oxygen, lithium or manganese is in the [0-11] direction or The layers are stacked with an offset in the [00-1] direction or the

[0011] direction. Also, the dashed lines in Figure 4(A) In the region enclosed by the symbol, replacing manganese with lithium results in a configuration similar to that shown in Figure 4(B). In other words, although the types of metal atoms are different, the positions of the metal atoms are roughly the same. Therefore, the two structures have many similarities, and it is thought that they will be compatible when stacked.

[0137] Furthermore, it is preferable that the second region has a different composition from the first region.

[0138] For example, the first region has lithium, manganese, element M and oxygen, and the second region is It contains lithium, manganese, element M and oxygen, and the first region contains lithium, manganese, element M The atomic ratio of oxygen is expressed as a1:b1:c1:d1, and lithium in the second region, ma When the atomic ratio of gan, element M, and oxygen is expressed as a²:b²:c²:d², Let me explain. Here, d1÷(b1+c1) is preferably 2.2 or greater, and preferably 2.3 or greater. It is more preferable that it be between 2.35 and 3. Also, d²÷( b2 + c2) is preferably less than 2.2, and more preferably less than 2.1. It is even more preferable that the value is between 1.1 and 1.9.

[0139] Furthermore, the manganese in the second region has a different valency than the manganese in the first region. It is also permissible. Furthermore, the element M present in the second region has a different value than the element M present in the first region. It may have a number.

[0140] Here, if there is a spatial distribution of the composition of each region or the valence of elements, for example, multiple locations The composition and valency of each region are evaluated, their average values ​​are calculated, and the composition and valency of that region are also evaluated. good.

[0141] Furthermore, a transition layer may be provided between the second region and the first region. Here, the transition layer is: For example, a region in which the composition changes continuously or stepwise. Alternatively, a transition layer is a crystal A transition layer is a region in which the structure changes continuously or stepwise. This is a region where the constant changes continuously or in steps.

[0142] Alternatively, a mixed layer may be present between the second region and the first region. Here, the mixed layer is For example, it refers to a layer in which two or more crystals with different crystal orientations are mixed. Alternatively, it refers to a mixed layer and This refers to a layer in which two or more crystals with different crystal structures are mixed. Alternatively, it can refer to a mixed layer. This refers to a layer in which two or more crystals with different compositions are mixed.

[0143] Here, the first region preferably has a layered rock salt structure. The second region is It is preferable that it has at least one of the following structures: spinel-type structure or layered salt-type structure. stomach.

[0144] Here, for example, using "particles having lithium manganese composite oxide" according to one aspect of the present invention When manufacturing a storage battery, etc., in each step of the process up to manufacturing the storage battery, the first area to the second area A region of 3 may be formed.

[0145] For example, the first to third regions are formed before electrode fabrication, for example, after particle synthesis. Alternatively, they may be formed during the electrode formation process. Also, for example, in the synthesis of particles. The thickness, composition, and crystal structure of the first to third regions formed later determine the electrode formation. It may change during the process.

[0146] Furthermore, the first to third regions are shaped during the heat treatment process in each step of manufacturing storage batteries, etc. It may be done.

[0147] In the process of producing lithium manganese composite oxide, as shown in S15, the primary particles are sintered. The disintegration process of lithium manganese composite oxide is a crucial step that affects the characteristics of the battery. In the crushing process, the primary particles are sintered into lithium manganese composite oxide, and shear ( By applying crushing stress, a powdered lithium manganese composite oxide is formed. In this case, if the lithium manganese composite oxide has a layered rock salt type crystal structure, the layers The cleavage and fracture of primary particles in planes parallel to each other or in planes perpendicular to each other. There are. In this specification, particles that have been cleaved and broken are referred to as grains having a cleavage surface. These are called particles, or particles with exposed cleavage planes. Note that the cleavage plane of a broken primary particle is also exposed. This also includes those who do not possess.

[0148] Furthermore, lithium manganese composite oxides having a layered rock salt-type crystal structure have cleavage properties. When using particles as an active material, this process is necessary not only during the crushing process but also during the electrode fabrication process. When pressure is applied to the electrodes during molding, the active material layer is subjected to pressure, causing the active material to... It can sometimes crack.

[0149] Furthermore, when manufacturing wound batteries, significant stress is applied to the electrodes during winding. Even when the electrode winding is housed in a casing, a stress always acts outward from the winding axis. Therefore, there is a risk that the active material may break further.

[0150] In this way, the primary particles of the lithium manganese composite oxide, which is the active material, cleave and break apart. This can lead to a decrease in the battery's discharge capacity and a deterioration in its cycle performance.

[0151] In such cases as well, a carbon-containing layer is formed on the cleavage surface of the lithium manganese composite oxide. It is preferable to provide it. Furthermore, the carbon-containing layer may cover the entire cleavage surface, or The entire lithium manganese composite oxide having an open surface may be covered. Here, an open surface is For example, including surfaces exposed by cleavage.

[0152] One aspect of the present invention is a configuration in which graphene is formed to cover a lithium manganese composite oxide. Graphene may be provided on the entire surface of the lithium manganese composite oxide, or in part. It may be provided only in the particle. It is preferable that the cleavage surface of the lithium manganese composite oxide be at least It is sufficient for graphene to be present in a portion of the material. At least a portion of the cleavage surface must be covered with graphene. By using a specially selected active material in the electrodes, the decrease in battery voltage and discharge capacity can be suppressed. This allows for improved battery cycle characteristics during charging and discharging. .

[0153] Graphene possesses excellent physical properties, including high flexibility and mechanical strength. Therefore, by using electrodes containing the active material in a battery, the battery undergoes repeated charging and discharging, Even if lithium manganese composite oxide expands and contracts, the volume change will affect the lithium manganese composite This prevents the oxide from further cleaving and cracking.

[0154] Furthermore, in the electrode manufacturing process, when pressure is applied to the electrode during shaping, lithium manganese compound The pressure on the composite oxide can be alleviated by the mechanical strength of graphene. This prevents the lithium manganese composite oxide from further cleaving and cracking. Cut.

[0155] Furthermore, in wound-type batteries, if a large stress is applied during the winding of the electrodes, or if the electrodes Assuming that when the winding body is housed in the casing, a constant stress is applied to the electrodes toward the outward direction of the winding axis Furthermore, it is possible to prevent the lithium manganese composite oxide from further cleaving and cracking. Cut.

[0156] <Electrode configuration> Next, an electrode using particles, which is one aspect of the present invention, will be described.

[0157] Figure 5(A) is an overhead view of electrode 100, and Figure 5(B) is the area enclosed by the dashed line in Figure 5(A). This is a diagram showing a cross-section of a part. The electrode 100 has an active material layer 102 provided on the current collector 101. This is the structure. In Figure 5(A), the active material layer 102 is provided on both sides of the current collector 101. As an example, the active material layer 102 may be provided on only one side of the current collector 101.

[0158] As long as the current collector 101 exhibits high conductivity without causing significant chemical changes within the energy storage device There are no special restrictions. For example, stainless steel, gold, platinum, zinc, iron, nickel, copper, aluminum. Metals such as nium, titanium, tantalum, and manganese, as well as their alloys, sintered carbon, etc. Alternatively, copper or stainless steel can be coated with carbon, nickel, titanium, etc. It is also possible to improve the heat resistance of materials such as silicon, neodymium, scandium, and molybdenum. Aluminum alloys to which elements that react with silicon can be used. It may be formed from a metallic element capable of forming a silicide by reacting with silicon. Metal elements that form silicides include zirconium, titanium, hafnium, and vanadium. These include chromium, niobium, tantalum, chromium, molybdenum, tungsten, cobalt, nickel, etc. Furthermore, the current collector 101 can be foil-shaped, plate-shaped (sheet-shaped), mesh-shaped, cylindrical, coil-shaped, or punch-shaped. Various forms including solid metal, expanded metal, porous, and nonwoven fabrics. The shape can be used as appropriate. Furthermore, to improve adhesion with the active material layer, the current collector 10 1 may have fine irregularities on its surface. Also, the current collector 101 has a thickness of 5 μm or more. It is best to use particles with a size of 0 μm or less.

[0159] The active material layer 102 contains an active material. The active material is responsible for the insertion and removal of ions, which are carriers. While it refers only to the substances involved, in this specification, in addition to the material that is originally the "active material," conductive aids The active material layer also includes agents and binders.

[0160] When using a negative electrode active material as the active material, for example, carbon-based materials, alloy-based materials, etc., are used. It is possible.

[0161] Furthermore, carbon-based materials include graphite, easily graphitizable carbon (soft carbon), and poorly graphitizable carbon. Examples include carbon (hard carbon), carbon nanotubes, graphene, and carbon black. .

[0162] Graphite includes mesocarbon microbeads (MCMB), coke-based artificial graphite, and pip There are artificial graphites such as cyanide-based artificial graphite and natural graphites such as spheroidized natural graphite.

[0163] The potential when lithium ions are inserted into graphite (during the formation of lithium-graphite intercalation compounds) is It exhibits a potential as low as lithium metal (0.1V to 0.3V vs. Li / L). i + This allows lithium-ion secondary batteries to exhibit a high operating voltage. Furthermore, graphite has a relatively high volume per unit volume, low volume expansion, and is inexpensive. It is preferable because it has advantages such as higher safety compared to um metals.

[0164] As the negative electrode active material, an alloying material can be used. Here, as the alloying material, A material capable of undergoing a charge-discharge reaction by providing an alloy with a metal that acts as a carrier ion. These can also be used. For example, Ga, Si, Al, Ge, Sn, Pb, Sb, Bi, A Materials containing at least one of g, Zn, Cd, In, etc. can be used. The elements have a larger capacity compared to carbon, and in particular, silicon has a theoretical capacity of 4200 mAh / g. Because of this high value, the capacity of energy storage devices can be increased. Alloy materials using such elements Examples include SiO, Mg2Si, Mg2Ge, SnO, SnO2, Mg2Sn, SnS2, V2Sn3, FeSn2, CoSn2, Ni3Sn2, Cu6Sn5, Ag3 Sn, Ag3Sb, Ni2MnSb, CeSb3, LaSn3, La3Co2Sn7, C Examples include oSb3, InSb, and SbSn.

[0165] Here, in order to increase the capacity of the energy storage device, a silicon-containing material is used as the negative electrode active material. For example, silicon or SiO is particularly preferred. Here, SiO refers to silicon It is a compound containing silicon and oxygen, and if the atomic ratio of silicon to oxygen is silicon:oxygen = α:β, then α It is preferable that the values ​​have a neighborhood to β. Here, having neighborhood values ​​means, for example, α and β. The absolute value of the difference is preferably 20% or less, more preferably 10% or less, with respect to the value of β. That's all you need to do.

[0166] Furthermore, titanium dioxide (TiO2) and lithium titanium oxide (Li4) are used as negative electrode active materials. Ti5O 12 ), lithium-graphite intercalation compound (Li x C6), niobium pentoxide (Nb2O5) ), use oxides such as tungsten oxide (WO2) and molybdenum oxide (MoO2). It is possible.

[0167] Furthermore, as the negative electrode active material, a Li3N type structure, which is a lithium and transition metal binitride, is also used. TsuLi 3-x M x N (M = Co, Ni, Cu) can be used. For example, Li 2. 6Co 0.4 The N3 has a large charge / discharge capacity (900mAh / g, 1890mAh / cm²). 3 )of This is preferable.

[0168] When using a lithium-transition metal binitride, lithium ions are included in the negative electrode active material. In combination with materials such as V2O5 and Cr3O8 that do not contain lithium ions as the positive electrode active material. It is preferable that this be done. Furthermore, when using a material containing lithium ions as the positive electrode active material, Also, by pre-desorbing the lithium ions contained in the positive electrode active material, the negative electrode active material and Therefore, a lithium-transition metal composite can be used.

[0169] Furthermore, materials that undergo a conversion reaction can also be used as the negative electrode active material. For example For example, lithium, such as cobalt oxide (CoO), nickel oxide (NiO), and iron oxide (FeO). Transition metal oxides that do not undergo alloying reactions with chromium may be used as the negative electrode active material. The materials that can react are also Fe2O3, CuO, Cu2O, RuO2, and Cr2 Oxides such as O3, CoS 0.89, sulfides such as NiS and CuS, Zn3N2, Cu3N, Nitrides such as Ge3N4, phosphides such as NiP2, FeP2, CoP3, FeF3, BiF This can also occur with fluorides of grade 3.

[0170] When a positive electrode active material is used as the active material, lithium ions are inserted into the positive electrode active material. and materials that can be detached can be used. For example, olivine type structure, layered rock salt type structure Materials with a spinel-type structure, NASICON-type crystal structure, etc. can be used. Cut.

[0171] In this embodiment, particles having a lithium manganese composite oxide are used as the positive electrode active material. I will explain the case where it is present, but it may also have other active materials. Examples of other active materials include For example, LiFeO2, LiCoO2, LiNiO2, LiMn2O4, V2O5, Cr2 Compounds such as O5 and MnO2 can be used as materials.

[0172] Alternatively, lithium-containing complex phosphate (general formula LiMPO4(M is Fe(II), Mn (II), Co(II), Ni(II) (one or more) can be used. General formula Li Typical examples of MPO4 include LiFePO4, LiNiPO4, LiCoPO4, and LiM nPO4, LiFe a Ni b PO4, LiFe a Co b PO4, LiFe a Mn b PO4 Li Limited a Co b PO4, LiNi a Mn b PO4(a+b is less than or equal to 1, 0 <a<1、0 <b<1)、LiFe c Ni d Coe PO4, LiFe c Ni d Mn e PO4, LiNi c Co d Mn e PO4 (where c + d + e is less than or equal to 1, 0 < c < 1, 0 < d < 1, 0 < e < 1), LiFe f Ni g Co h Mn i PO4 (where f + g + h + i is less than or equal to 1, 0 < f < 1, 0 < g < 1, 0 < h < 1, 0 < i < 1), etc. Lithium metal phosphate compounds such as these can be mentioned.

[0173] Or, a lithium - containing complex silicate such as the general formula Li (2-j) MSiO4 (M is one or more of Fe(II), Mn(II), Co (II), Ni(II), 0 ≤ j ≤ 2) can be used. For the general formula Li (2-j) MSiO4, representative examples include Li (2-j) Fe SiO4, Li (2-j) NiSiO4, Li (2-j) CoSiO4, Li (2-j) MnSiO4, Li (2-j) Fe k Ni l SiO4, Li (2-j) Fe k Co l Si O4, Li (2-j) Fe k Mn l SiO4, Li (2-j) Ni k Co l SiO4, L i (2-j) Ni k Mn l SiO4 (where k + l is less than or equal to 1, 0 < k < 1, 0 < l < 1), Li (2-j) Fe m Ni n Co q SiO4, Li (2-j)Fe m Ni n Mn q SiO4, Li (2-j) Ni m Co n Mn q SiO4 (where m + n + q is 1 or less, 0 < m < 1, 0 < n < 1, 0 < q < 1), Li (2-j) Fe r Ni s Co t Mn u SiO4 (r + s + t + u is 1 or less, 0 < r < 1, 0 < s < 1, 0 < t < 1, 0 < u < 1), etc. Lithium silicate compounds are exemplified.

[0174] Also, as the active material, A x M2(XO4)3 (A = Li, Na, Mg, M = Fe, Mn , Ti, V, Nb, Al, X = S, P, Mo, W, As, Si) represented by the general formula NA SICON type compounds can be used. Examples of NASICON type compounds include Fe2( MnO4)3, Fe2(SO4)3, Li3Fe2(PO4)3, etc. Also, as the positive electrode active material, compounds represented by the general formula Li2MPO4F, Li2MP2O7, Li5MO4 (M = Fe, M n), perovskite type fluorides such as NaF3, FeF3, T iS2, MoS2 and other metal chalcogenides (sulfides, selenides, tellurides), LiM VO4 and other materials having an inverse spinel type crystal structure, vanadium oxide based (V2O5, V6 O 13 , LiV3O8, etc.), manganese oxides, organic sulfur compounds and other materials can be used. can be.

[0175] Note that the carrier ion is an alkali metal ion other than lithium ion, an alkaline earth metal In the case of group ions, the above lithium compound and lithium-containing composite phosphoric acid are used as positive electrode active materials. In salts and lithium-containing composite silicates, lithium is replaced with an alkali metal (e.g., sodium (e.g., lium and potassium), alkaline earth metals (e.g., calcium, strontium, burr) Compounds substituted with carriers such as um, beryllium, and magnesium may also be used.

[0176] The average particle size of the positive electrode active material is preferably, for example, 5 nm to 50 μm.

[0177] Furthermore, the active material layer 102 may contain a conductive additive. Examples of conductive additives include natural graphite. Artificial graphite such as mesocarbon microbeads, carbon fibers, etc. can be used. Examples of fibers include mesophase pitch carbon fibers, isotropic pitch carbon fibers, and other carbon fibers. Fibers can be used. In addition, carbon nanofibers and carbon Nanotubes can be used, for example. Carbon nanotubes can be grown using vapor phase growth methods. It can be manufactured in various ways. Also, as a conductive additive, for example, carbon black (acetylene Carbon materials such as amber black (AB) or graphene can be used. For example, metal powders and metal fibers such as copper, nickel, aluminum, silver, and gold, and conductive ceramics. Materials such as acrylic can be used.

[0178] Graphene in flake form has excellent electrical properties, including high conductivity, as well as flexibility. It possesses excellent physical properties, including mechanical strength. Therefore, graphene is used as a conductive additive. By using this method, the number of contact points and contact area between active materials can be increased.

[0179] The active material layer 102 preferably has a binder, and the binder is a water-soluble polymer. It is more preferable that the active material layer 102 has multiple types of binders. That's good too.

[0180] The binders used are polyvinylidene fluoride (PVdF), polystyrene, and polyacrylic. Methyl methacrylate, polymethyl methacrylate (PMMA), sodium polyacrylate, polymethyl methyl methacrylate Nyl alcohol (PVA), polyethylene oxide (PEO), polypropylene oxide Polyimide (PI), polyvinyl chloride, polytetrafluoroethylene, polyethylene, Polypropylene, isobutylene, polyethylene terephthalate, nylon, polyacrylo It is preferable to use materials such as nitrile (PAN).

[0181] Additionally, styrene-butadiene rubber (SBR) and styrene-isoprene are used as binders. Styrene rubber, acrylonitrile butadiene rubber, butadiene rubber, ethylene pro Rubber materials such as pyrene-diene copolymers can be used. These rubber materials are water It is even more preferable to use it in combination with a soluble polymer. These rubber materials have rubber elasticity. Because it is easily stretched and contracted, the active material expands and contracts during charging and discharging, and stretches due to bending of electrodes, etc. While it allows for the creation of highly reliable electrodes that are resistant to corrosion, it also has hydrophobic groups and is poorly soluble in water. In such cases, the particles are dispersed in an aqueous solution without dissolving in water. A composition containing a solvent used to form the active material layer 102 (also called an electrode mixture composition) is applied. It can be difficult to raise the viscosity to a level suitable for weaving. In this case, viscosity adjustment function Using highly water-soluble polymers, such as polysaccharides, can be expected to moderately increase the viscosity of the solution. Furthermore, the rubber material disperses uniformly with each other, resulting in a highly uniform and excellent electrode, such as an electrode film thickness. This allows for the creation of electrodes with high uniformity of electrode resistance.

[0182] As water-soluble polymers, for example, polysaccharides can be used. Examples of polysaccharides include: Carboxymethylcellulose (CMC), methylcellulose, ethylcellulose, hydro Celluloses such as xypropylcellulose, diacetylcellulose, and regenerated cellulose. Derivatives, starch, etc., can be used.

[0183] Each binder can be used individually, or two or more types can be used in combination. stomach.

[0184] <Method for fabricating electrodes> Next, a method for manufacturing an electrode 100, which is one aspect of the present invention, will be described.

[0185] First, an electrode mixture composition is prepared. The electrode mixture composition is prepared, for example, using the active material described above. It can be prepared by adding binders, conductive additives, etc., and kneading them together with a solvent. The electrode mixture composition may be in the form of a slurry or a paste. For example, water or NMP (N-methyl-2-pyrrolidone) can be used. From the standpoint of safety and cost, using water is preferable.

[0186] As an example, let's explain the case where electrode 100 is the positive electrode for a storage battery. Here, the active material is Using an active material according to one aspect of the present invention, acetylene black is used as a conductive additive, and This section describes an example using PVdF as the lead and NMP as the solvent.

[0187] First, an active material according to one aspect of the present invention, acetylene black, and polyvinylidene fluoride. Mix the two ingredients. Add NMP to these mixtures until the desired viscosity is reached, and knead the mixture. In this process, an electrode mixture composition can be formed. The addition can be repeated multiple times. The electrode mixture can be in slurry or paste form. That's fine.

[0188] Through the above process, an electrode mixture composition is obtained in which the active material, conductive additive, and binder are uniformly dispersed. It is possible to form this.

[0189] Here, an undercoat may be formed on the current collector. Note that the undercoat is... This refers to a coating layer designed to reduce contact resistance and improve adhesion between the current collector and the active material layer. Examples of layers include a carbon layer, a metal layer, a layer containing carbon and polymer, and a layer containing metal and polymer. A layer containing molecules can be used. By forming an undercoat on the current collector, The contact resistance between the current collector and the active material layer formed later can be reduced. This improves adhesion with the active material layer. The undercoat contains a conductive additive. When using graphene oxide, in the reduction step of graphene oxide, substances that do not dissolve in the reducing solution It is preferable to do so.

[0190] Furthermore, as an undercoat, for example, a dispersed aqueous solution of graphite or acetylene black can be used. Alternatively, a solution containing a polymer can be used, for example, graphite and polyamide. Using a mixture with sodium acrylate (PAA), or a mixture of AB and PVdF, etc. It is possible to do so. Also, the weight ratio of graphite to PAA is graphite:PAA = 95:5 to 50: Within the range of 50, the mixing ratio of AB to PVdF is AB:PVdF = 70:30 to 50:50. It should be within that range.

[0191] Furthermore, if there are no problems with the adhesion between the active material layer and the current collector, the electrode strength, or the contact resistance, then the undercarriage... - The coating does not necessarily need to be formed on the current collector.

[0192] Next, the slurry is applied to one or both sides of the current collector using a coating method such as the doctor blade method. It will be established by [means].

[0193] Next, the slurry placed on the current collector is dried by methods such as ventilation drying or reduced pressure (vacuum) drying. This process forms an active material layer. This drying is performed, for example, by heating to a temperature between 50°C and 180°C. This step is best done using air. This step evaporates the polar solvent contained in the active material layer. The atmosphere is not particularly limited.

[0194] Here, pressure is applied to this active material layer by compression methods such as the roll press method or the plate press method. The density of the active material layer may be increased by doing so. Also, when pressing, the temperature should be 90°C or higher for 18 minutes. By applying heat below 0°C, preferably below 120°C, the undercoat and active material layer are transformed. The binder (e.g., PVdF) contained in the electrode is softened to an extent that does not change the characteristics of the electrode. This further enhances the adhesion between the current collector and the active material layer.

[0195] Next, the active material layer is heat-treated to evaporate the solvent. The heat treatment is performed under reduced pressure (vacuum). This should be carried out under a reducing atmosphere. This heat treatment process should be, for example, between 50°C and 600°C. Furthermore, more preferably 120°C to 500°C, more preferably 200°C to 400°C This process should be carried out at the following temperatures for a period of 1 hour to 48 hours. This heat treatment will create an active material layer. To evaporate or remove polar solvents and water present in the solution.

[0196] Here, for example, using "particles having lithium manganese composite oxide" according to one aspect of the present invention When electrodes are fabricated and a storage battery is manufactured using these electrodes, the term "lithium manganese composite oxide" is used. The first to third regions of the "particle having" are "lithium manganese composite oxide It is formed in either the manufacturing process of the "particles having" or the manufacturing process of the storage battery. That's good too.

[0197] <Heat treatment> Here, by performing heat treatment, for example, one aspect of the present invention, "lithium manganese composite" In particles containing oxides, a first to a third region may be formed.

[0198] Furthermore, the first to third regions possessed by "particles having lithium manganese composite oxide" The region may be formed before electrode fabrication, for example, after particle synthesis. Alternatively, during electrode formation... It may be formed during the process. Also, for example, a first region formed after particle synthesis. The thickness, composition, and crystal structure of the third region may change during the electrode formation process. Furthermore, the first to third regions are shaped during the heat treatment process in each step of manufacturing the storage battery, etc. It may be done.

[0199] Furthermore, by performing heat treatment, for example, the elements contained in the binder and lithium manganese can be separated. Particles containing a complex oxide may react with elements present in them. For example, This section explains the case where PVdF is used as the lead. PVdF is a polymer compound containing fluorine. By using a polymer compound containing fluorine as a binder, the electrode is constructed from... The bonding between fluorine and elements in other materials, such as active materials, conductive additives, and current collectors, forms a shape This may occur. Here, having a bond means, for example, analyzing using XPS, etc. It refers to the observable bonding state. Alternatively, having a bond means, for example, a material having such a bond. It refers to having a material. For example, metal fluorides are materials that have such a bond. Examples include the lithium manganese composite acid according to one embodiment of the present invention, as a metal fluoride. The fluoride forms metallic fluorides with the metals lithium, manganese, and element M. In some cases, this may occur. Alternatively, it may form a bond with the metal used in the current collector.

[0200] Alternatively, a coating layer of lithium manganese composite oxide, for example, a layer containing carbon, is shown here. However, elements contained in the coating layer and fluorine may form a bond. For example, the coating layer and And when a layer containing carbon is used, fluorinated carbon may be formed. Here, the coating layer This may include the third region possessed by "particles having lithium manganese composite oxide". Furthermore, it may have a third region and a part of the first or second region. The second region of the "particles having lithium manganese composite oxide" is, for example, the coating layer. It may have a part of it.

[0201] By forming such bonds, for example, the strength of the electrodes can be increased. In some cases, a battery can be manufactured by forming a bond in advance. Afterward, irreversible reactions can sometimes be suppressed during the charging and discharging of the battery. The volume of the active material may change, which may lead to a decrease in electrode strength. When this decreases, for example, the adhesion between active materials themselves, or between active materials and conductive additives, decreases. The conductive paths of the electrodes may decrease, leading to a reduction in capacitance. In such cases, such coupling... By forming this, the strength of the electrode is improved, and the electrode's resistance to volume changes is enhanced. There are cases where this is the case.

[0202] A preferred heat treatment temperature for forming a bond is, for example, 120°C or higher, more preferably The temperature is 160°C or higher, more preferably 200°C or higher, and more preferably 250°C or higher.

[0203] Furthermore, the heat treatment atmosphere can use gases such as oxygen, air, nitrogen, and noble gases. Furthermore, the heat treatment may be performed under atmospheric pressure or under reduced pressure. Here, for example, oxygen By using the gas present, each material constituting the electrode, such as lithium manganese composite acid, can be controlled. The reaction between the monoxide-containing particles and the binder may be accelerated. Here the binder -The reaction is promoted, for example, between the elements of the binder and lithium manganese compound The bonding between elements in particles containing the composite oxide can be observed by analysis such as XPS. This refers to the use of inert gases such as nitrogen and noble gases to control the composition of each electrode. In some cases, it is possible to suppress the deterioration of materials, such as current collectors. Also, heat treatment under reduced pressure By performing this process, it is possible to suppress the deterioration of each material that makes up the electrodes, such as the current collector. It is sometimes possible.

[0204] If the heat treatment temperature is too high, decomposition of the materials constituting the electrodes may occur. Yes, for example, particles containing lithium manganese composite oxide undergo a decomposition reaction and become a storage battery. Using it may reduce its capacity. Therefore, the heat treatment temperature is 600°C. The following are preferred, 500°C or less is more preferred, and 400°C or less is even more preferred.

[0205] <Press> Furthermore, the current collector on which the active material layer has been formed may be subjected to pressing. This will result in the active material layer This improves adhesion with the current collector. Furthermore, it allows for an increase in the density of the active material layer. Furthermore, when pressing, heat is applied at a temperature of 90°C to 180°C, preferably 120°C or lower. By doing so, the binder (e.g., PVdF) contained in the undercoat and active material layer can be removed. By softening the electrode to an extent that does not change its properties, the adhesion between the current collector and the active material layer is improved. It can be further enhanced.

[0206] Finally, the electrodes are fabricated by punching out the current collector and active material layer to a predetermined size. ru.

[0207] In this embodiment, one aspect of the present invention has been described. Or, other embodiments may be described. In this context, one aspect of the present invention will be described. However, this aspect of the present invention is not limited to these. Not done. In other words, various aspects of the invention are described in this embodiment and other embodiments. Therefore, one aspect of the present invention is not limited to a specific aspect. For example, one aspect of the present invention As an example, an example of its application to lithium-ion secondary batteries has been shown, but one aspect of the present invention is this This is not limited to the present invention. Depending on the circumstances, one aspect of the present invention may apply to various situations. Secondary batteries, lead-acid batteries, lithium-ion polymer secondary batteries, nickel-metal hydride batteries, nickel Lu-cadmium batteries, nickel-iron batteries, nickel-zinc batteries, silver oxide-zinc batteries Ponds, solid-state batteries, air batteries, primary batteries, capacitors, or lithium-ion capacitors, This may also be applied to the following. Or, for example, depending on the circumstances, the present invention may be applied to the following. One embodiment of the present invention does not need to be applied to lithium-ion secondary batteries. The example shown was that the active material is graphene or graphene oxide, but this development One aspect of the present invention is not limited thereto. Depending on the circumstances, the present invention may also be described in some cases or situations. In one embodiment, graphene or graphene oxide is a capacitor with very large capacitance. It is used as an electrode for supercapacitors (electric double-layer capacitors), or as an oxygen reduction electrode. It can be used as an electrode catalyst, as a material for dispersed water with lower friction than lubricating oil, or in display devices and thick... It can be used as a transparent electrode for solar cells, as a gas barrier material, or for its mechanical strength. It is used as a high-quality, lightweight polymer material, and for uranium and plutonium contained in radioactive contaminated water. It is used as a material for highly sensitive nanosensors to detect um, or to remove radioactive materials. It can also be used as material for that purpose.

[0208] This embodiment can be implemented in appropriate combination with other embodiments.

[0209] (Embodiment 2) This embodiment shows an example of an energy storage device using electrodes, which is one aspect of the present invention.

[0210] In this specification, the term "energy storage device" refers to all elements and devices that have an energy storage function. For example, rechargeable batteries such as lithium-ion secondary batteries, lithium-ion capacitors, and This includes electric double-layer capacitors, etc.

[0211] <Thin-type rechargeable battery> Figure 6 shows a thin battery as an example of an energy storage device. The thin battery is flexible. If the configuration is such that it can be mounted on an electronic device having at least a part of a flexible component, Furthermore, the battery can be bent to match the deformation of the electronic device.

[0212] Figure 6 shows an external view of the thin battery 500. Also, Figures 7(A) and 7(B) are shown. Section 6 shows the A1-A2 and B1-B2 cross-sections, indicated by dashed lines. The thin battery 500 is A positive electrode 503 having a positive electrode current collector 501 and a positive electrode active material layer 502, and a negative electrode current collector 504 and a negative electrode 506 having a negative electrode active material layer 505, a separator 507, and an electrolyte 508. , comprising an outer casing 509 and a positive electrode 503 and a negative electrode 506 provided within the outer casing 509 A separator 507 is installed in between. Also, the inside of the outer casing 509 is filled with electrolyte 508. It is being done.

[0213] At least one of the positive electrode 503 and the negative electrode 506 is an electrode according to one aspect of the present invention. Furthermore, even if electrodes according to one aspect of the present invention are used for both the positive electrode 503 and the negative electrode 506, good.

[0214] First, the configuration of the positive electrode 503 will be described. The positive electrode 503 has an electric component according to one aspect of the present invention. It is preferable to use electrodes. Here, the positive electrode 503 is the electrode 100 shown in Embodiment 2. An example of its use is shown.

[0215] As the solvent for electrolyte 508, an aprotic organic solvent is preferred, for example, ethylene carbonate Carbonate (EC), propylene carbonate (PC), butylene carbonate, chloro Ethylene carbonate, vinylene carbonate (VC), γ-butyrolactone, γ-valence Lolactone, dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl Methyl carbonate (EMC), methyl formate, methyl acetate, methyl butyrate, 1,3-dimethyl carbonate Xane, 1,4-dioxane, dimethoxyethane (DME), dimethyl sulfoxide, di Ethyl ether, methyl diglyme, acetonitrile, benzonitrile, tetrahydrof One of the following: ran, sulfolane, sultone, etc., or any combination of two or more of these. It can also be used in ratios.

[0216] Furthermore, by using a polymer material that gels as the solvent for the electrolyte, leakage properties can be addressed. Safety is enhanced. Furthermore, it becomes possible to make secondary batteries thinner and lighter. The high-molecular-weight components that are gelled... Typical examples of these materials include silicone gel, acrylic gel, acrylonitrile gel, and poly Ethylene oxide gels, polypropylene oxide gels, fluorine polymer gels These include:

[0217] Furthermore, as the solvent for the electrolyte, an ionic liquid (a room-temperature molten salt) that is flame-retardant and non-volatile is used. By using one or more of these devices, the internal temperature of the energy storage device may rise due to internal short circuits or overcharging. However, this can prevent the rupture or ignition of the energy storage device. Ionic liquids are composed of cations and anions. It consists of and contains organic cations and anions. As organic cations used in the electrolyte, four quaternary ammonium cations, tertiary sulfonium cations, and quaternary phosphonium cations Aliphatic onium cations such as imidazolium cations and pyridinium cations, etc. Aromatic cations are an example. In addition, monovalent amides are used as anions in the electrolyte. Anions, monovalent methide anions, fluorosulfonate anions, perfluoroalkyl Anions of tetrafluoroborate, perfluoroalkylborate, hex Examples include safluorophosphates or perfluoroalkyl phosphates.

[0218] Furthermore, when using lithium ions as the carrier, the electrolyte to be dissolved in the above solvent... For example, LiPF6, LiClO4, LiAsF6, LiBF4, LiAlCl4, L iSCN, LiBr, LiI, Li2SO4, Li2B 10 Cl 10 Li2B 12 Cl 12 , LiCF3SO3, LiC4F9SO3, LiC(CF3SO2)3, LiC(C 2F5SO2)3, LiN(CF3SO2)2, LiN(C4F9SO2)(CF3SO 2) One type of lithium salt such as LiN(C2F5SO2)2, or two or more of these. These can be used in any combination and ratio.

[0219] Furthermore, the electrolyte used in the energy storage device may contain particulate debris and elements other than the constituent elements of the electrolyte (hereinafter, It is preferable to use a highly purified electrolyte with a low content of impurities (also simply called "impurities"). Specifically, the weight ratio of impurities to the electrolyte should be 1% or less, preferably 0.1% or less. More preferably, it is 0.01% or less.

[0220] In addition, the electrolyte contains vinylene carbonate (VC), propane sultone (PS), and tert -Butylbenzene (TBB), fluoroethylene carbonate (FEC), LiBOB Any additive may be added. The concentration of the additive should be, for example, 0.1 weig relative to the total solvent. It should be between ht% and 5weight%.

[0221] Alternatively, a gel electrolyte obtained by swelling a polymer with an electrolyte solution may be used. An example of a gel electrolyte is one in which a host polymer is used as the support and the above-mentioned electrolyte is contained. Examples include:

[0222] Examples of host polymers are described below. Polyethylene is an example of a host polymer. Polymers having polyalkylene oxide structures such as oxides (PEO), and PVdF, Polyacrylonitrile and the like, and copolymers containing them, can be used. For example, PVdF-HF is a copolymer of PVdF and hexafluoropropylene (HFP). P can be used. Furthermore, the resulting polymer may have a porous structure.

[0223] In addition, instead of an electrolyte, a solid electrolyte containing inorganic materials such as sulfide-based or oxide-based materials may be used. Solid electrolytes containing polymer materials such as PEO (polyethylene oxide) can be used. It is possible. When using a solid electrolyte, the installation of separators and spacers becomes unnecessary. Also, Because the entire battery can be made solid, the risk of leakage is eliminated, dramatically improving safety.

[0224] For example, the separator 507 may be paper, nonwoven fabric, glass fiber, ceramics, or Nylon (polyamide), Vinylon (polyvinyl alcohol-based fiber), polyester, A This product uses synthetic fibers made from acrylic, polyolefin, polyurethane, etc. It is possible.

[0225] The separator 507 is processed into a bag shape and encloses either the positive electrode 503 or the negative electrode 506. It is preferable to arrange them in such a way. For example, as shown in Figure 8(A), the positive electrode 503 is sandwiched between them. The sea urchin separator 507 is folded in half, and the sealing portion 51 is formed outside the area that overlaps with the positive electrode 503. By sealing with 4, the positive electrode 503 can be securely supported within the separator 507. Then, as shown in Figure 8(B), the positive electrode 503 and negative electrode 5 are enclosed in the separator 507. By alternately stacking 06 and 509 and arranging them inside the outer casing 509, a thin storage battery 500 is formed. It is good to form it.

[0226] Here, the positive electrode active material is a lithium manganese composite oxide as shown in Embodiment 1. Using particles, the electrode shown in Embodiment 1 is used as the positive electrode 503, and silica is used as the negative electrode active material. An example using an active material containing CON will be explained.

[0227] Active materials containing silicon, such as silicon or SiO, have active material weight and active material volume. The capacity per unit area is large, and it is possible to increase the capacity per unit weight and per unit volume of the storage battery. ru.

[0228] Here, in addition to the insertion and removal reactions of carrier ions during the charging and discharging of a rechargeable battery, Decomposition reactions of the electrolyte may occur. This decomposition reaction occurs at both the positive and negative electrodes. This can occur. In particular, at the negative electrode, the electrolyte may not be able to withstand the low potential of the battery reaction. In many cases, decomposition occurs without the presence of the original substance. Such decomposition reactions are often irreversible. The reversible reaction reduces the charge and discharge efficiency of the energy storage device, leading to a decrease in capacity. There is a match.

[0229] In such cases, the negative electrode 506 or positive electrode 503 used in the storage battery, the counter electrode, and the electrolyte A battery is prepared with a pre-installed element, and an irreversible reaction is pre-induced in the battery. By removing the negative electrode 506 or the positive electrode 503 and fabricating a storage battery, the irreversible reaction can be prevented. This is preferable because it can suppress the reduction in battery capacity caused by [something]. On the other hand, [something else] Materials containing rear ions can be used. For example, metals containing carrier ions, or Compounds having rear ions can be used. As a metal having a carrier ion, Examples include lithium. Also, as a compound having a carrier ion, for example, The materials listed as the positive electrode active material and the negative electrode active material in Embodiment 1 can be used.

[0230] Next, we will explain the aging process after the battery has been manufactured. It is preferable to perform aging. An example of aging conditions is described below. First, Charge at a rate of 0.001C to 0.2C. The temperature should be, for example, above room temperature, 50°C. It should be kept below °C. If decomposition of the electrolyte occurs at this time and gas is generated, When gas accumulates inside the cell, areas are created where the electrolyte cannot come into contact with the electrode surface. In other words, this corresponds to a decrease in the effective reaction area of ​​the electrode and an increase in the effective current density. Furthermore, particles having a lithium manganese composite oxide according to one aspect of the present invention are positive electrode active material and When used in this manner, it has a high reaction potential. When the positive electrode active material has a high reaction potential... This allows for an increase in the battery voltage and thus an increase in the battery's energy density. preferable.

[0231] In some cases, the electrolyte may not be able to withstand such high reaction potentials. For example... In some cases, the electrolyte may decompose on the surface of the positive electrode, generating gas. It is preferable to release the gas.

[0232] Furthermore, if the current density becomes excessively high, a voltage drop occurs depending on the resistance of the electrodes, causing a decrease in the graphite. Simultaneously with the lithium insertion, lithium deposition occurs on the graphite surface. Precipitation can lead to a decrease in capacity. For example, after lithium is deposited, a film or other substance may form on the surface. If left untreated, the lithium deposited on the surface cannot be re-eluted, and the lithium that does not contribute to the capacity... The amount of lithium increases. Also, if the deposited lithium physically collapses and loses conductivity with the electrode... However, lithium that does not contribute to the capacity is still produced. Therefore, the electrodes are subjected to a voltage drop. It is preferable to release the gas before reaching the thium potential.

[0233] Alternatively, aging can be performed while pressing. For example, a thin rechargeable battery can be manufactured. Afterward, charging and discharging may be performed while pressing using a press machine.

[0234] Lithium manganese composite oxide according to one aspect of the present invention is preferred because it has a large discharge capacity. Furthermore, the lithium manganese composite oxide according to one embodiment of the present invention has a high potential for its battery reaction. It has a high energy density, which is preferable.

[0235] On the other hand, when an active material with a high battery reaction potential is used as the positive electrode of a storage battery, the electrolyte is divided In some cases, it is easier to understand. Here, the electrolyte decomposes, generating gas near the positive electrode surface. It may happen.

[0236] By performing aging while pressing, the generated gas is pressed out. It is preferable that the components can be moved to areas other than the designated area, such as the periphery of the battery.

[0237] Here, for example, pressing may be performed while heating. Also, before and after aging... While aging can be performed while pressing, it is preferable to perform aging while pressing.

[0238] Furthermore, after degassing, the temperature should be higher than room temperature, preferably between 30°C and 60°C. More preferably, at a temperature of 35°C to 50°C, for example, for 1 hour to 100 hours. It may be held in an electrically charged state. During the initial charging, the electrolyte that decomposed on the surface is returned to the surface of the graphite. A coating is formed. Therefore, for example, by holding it at a temperature higher than room temperature after degassing, It is also possible that the formed coating may become denser.

[0239] As shown in Figure 9(A), the positive electrode current collector of the positive electrode 503 is made using ultrasonic welding or the like. The positive lead electrode 510 is welded in the welding area 512. The negative electrode current collector of the negative electrode 506 It is welded to the negative lead electrode 511. Figure 9(B) shows an example of welding the current collector to the lead electrode. This is shown. As an example, an example of welding the positive electrode current collector to the positive electrode lead electrode 510 is shown. The electrical body has the curved portion 513 shown in Figure 9(B), which allows the battery 500 to be removed after it has been manufactured. This can alleviate the stress caused by applied force, thereby improving the reliability of the 500 battery. It is possible.

[0240] In the thin storage battery 500 shown in Figures 6 and 7, the positive lead electrode 510 is the positive electrode 50 The positive electrode current collector 501 of 3 and the negative electrode lead electrode 511 are the negative electrode current collector of the negative electrode 506 The positive lead electrode 510 and the negative lead electrode 511 are ultrasonically bonded to 504 respectively. It is exposed to the outside. Furthermore, the positive electrode current collector 501 acts as a terminal for obtaining electrical contact with the outside. It can also be combined with the negative electrode current collector 504. In that case, the positive electrode is used without using lead electrodes. The current collector 501 and a portion of the negative electrode current collector 504 are arranged to be exposed to the outside from the outer casing 509. You may place it there.

[0241] Furthermore, in Figure 6, the positive lead electrode 510 and the negative lead electrode 511 are arranged on the same side. However, as shown in Figure 10, the positive lead electrode 510 and the negative lead electrode 511 are on different sides. They may be arranged as follows. Thus, in one aspect of the present invention, the storage battery allows for the free arrangement of the lead electrodes. Therefore, it offers a high degree of design flexibility. This allows for increased design flexibility. Furthermore, it improves the productivity of products using a battery according to one embodiment of the present invention. It can improve.

[0242] In the thin battery 500, the outer casing 509 is made of, for example, polyethylene, polypropylene Aluminum is applied to a film made of materials such as cellulose, polycarbonate, ionomer, and polyamide. A highly flexible metal thin film such as aluminum, stainless steel, copper, or nickel is provided, and further on the metal thin film An insulating synthetic resin film, such as polyamide resin or polyester resin, is provided on the outer surface of the exterior body. A film with a three-layer structure can be used.

[0243] Also, in Figure 6, as an example, the number of pairs of opposing positive and negative electrodes is set to 5, but of course The number of electrode sets is not limited to 5; it can be more or fewer. This allows for the creation of a battery with a larger capacity. Also, when the number of electrode layers is small... This allows for a thinner design and enables the creation of a rechargeable battery with excellent flexibility.

[0244] In the above configuration, the casing 509 of the secondary battery has a radius of curvature of 30 mm or more, preferably a radius of curvature It can be deformed within a radius of 10 mm or more. The film that forms the outer casing of the secondary battery is If it is a secondary battery consisting of one or two layers and has a stacked structure, the bending of the battery will cause it to break. The surface structure is a structure sandwiched between two curves of the outer film.

[0245] The radius of curvature of a surface will be explained using Figure 11. In Figure 11(A), the curved surface 170 In the plane 1701 that cuts through 0, a portion of the curve 1702 contained in the curved surface 1700 is a circle Approximating it as an arc, let the radius of the circle be the radius of curvature 1703, and the center of the circle be the center of curvature 1704. Figure 11(B) shows a top view of the curved surface 1700. Figure 11(C) shows the curved surface on plane 1701. The cross-sectional view of 1700 is shown. When a curved surface is cut by a plane, the angle of the plane relative to the curved surface... The radius of curvature of the curve appearing in the cross-section will differ depending on the cutting position, but in this specification, etc. The smallest radius of curvature is defined as the radius of curvature of the surface.

[0246] A curved secondary battery was constructed using two films as an outer casing, sandwiching the electrodes, electrolyte, and other components of the 1805 battery. In this case, the radius of curvature 1802 of the film 1801 on the side closer to the center of curvature 1800 of the secondary battery. This is smaller than the radius of curvature 1804 of film 1803 on the side farther from the center of curvature 1800. Figure 12(A)). When the secondary battery is curved to make the cross-section arc-shaped, the center of curvature is close to 1800. Compressive stress is applied to the surface of the film, and tension is present on the surface of the film far from the center of curvature of 1800. Tension stress is applied (Figure 12(B)). Patterns are formed on the surface of the exterior body by recesses or protrusions. Once formed, even if compressive or tensile stresses are applied, the effects of strain remain. This can be kept within an acceptable range. Therefore, the secondary battery has an outer casing that is closer to the center of curvature. It can be deformed within a range where the radius of curvature is 30 mm or more, preferably 10 mm or more.

[0247] Furthermore, the cross-sectional shape of a secondary battery is not limited to a simple arc shape, but can also have a shape in which part of it is an arc. It is possible to create shapes such as the one shown in Figure 12(C), or wavy (Figure 12(D)), or S-shaped. It is also possible to do so. If the curved surface of the secondary battery has a shape with multiple centers of curvature, Among the radii of curvature at each of the number of curvature centers, in the surface with the smallest radius of curvature, 2 The radius of curvature of the outer casing closest to the center of curvature of each outer casing is 10 mm or more, preferably 30 mm. The secondary battery can be deformed within the range described above.

[0248] <Coin-type rechargeable battery> Next, as an example of an energy storage device, we will explain an example of a coin-type battery with reference to Figure 13. Figure 13(A) is an external view of a coin-type (single-layer flat-type) storage battery, and Figure 13(B) is This is a cross-section of it.

[0249] The coin-type rechargeable battery 300 consists of a positive electrode can 301 which also serves as the positive terminal and a negative electrode can which also serves as the negative terminal. 302 is insulated and sealed by a gasket 303 made of polypropylene or the like. The positive electrode 304 consists of a positive electrode current collector 305 and a positive electrode active material layer 306 provided in contact with it. It is formed by [the following]. For the positive electrode active material layer 306, please refer to the description of the positive electrode active material layer 502. .

[0250] Furthermore, the negative electrode 307 consists of a negative electrode current collector 308 and a negative electrode active material provided in contact with it. It is formed by layer 309. For details of the negative electrode active material layer 309, refer to the description of the negative electrode active material layer 505. That should be done. Also, for separator 310, refer to the description for separator 507. For the dissolution solution, refer to the description for electrolyte 508.

[0251] Furthermore, the positive electrode 304 and negative electrode 307 used in the coin-type storage battery 300 are each live metal The layers only need to be formed on one side.

[0252] The positive electrode can 301 and negative electrode can 302 are made of nickel and aluminum, which are corrosion-resistant to the electrolyte. Metals such as um, titanium, or alloys thereof, or alloys of these with other metals (for example, stainless steel) Steel (such as aluminum) can be used. In addition, nickel and aluminum can be used to prevent corrosion by the electrolyte. It is preferable to coat with nium or the like. The positive electrode can 301 is the positive electrode 304, and the negative electrode can 302 is the negative electrode Connect each of the 307s electrically.

[0253] These negative electrode 307, positive electrode 304, and separator 310 are impregnated with the electrolyte, as shown in Figure 13. As shown in B), with the positive electrode can 301 at the bottom, the positive electrode 304, separator 310, and negative electrode 307... The negative electrode can 302 is stacked in this order, and the positive electrode can 301 and the negative electrode can 302 are connected by a gasket 303. The coin-shaped rechargeable battery 300 is manufactured by crimping the components together.

[0254] <Cylindrical storage battery> Next, as an example of an energy storage device, a cylindrical battery is shown. Figure 14 shows the cylindrical battery. The cylindrical storage battery 600 has a positive electrode on its top surface, as shown in Figure 14(A). It has a cap (battery cover) 601 and battery cans (outer cans) 602 on the sides and bottom. These positive electrode caps and battery can (outer can) 602 are connected by a gasket (insulating packing) 6 It is insulated by 10.

[0255] Figure 14(B) is a schematic diagram showing a cross-section of a cylindrical storage battery. Inside can 602, a strip-shaped positive electrode 604 and a negative electrode 606 are separated by a separator 605. A wound battery element is provided. Although not shown in the diagram, the battery element is centered around the center pin. It is wound up. Battery can 602 is closed at one end and open at the other end. This is a metal such as nickel, aluminum, or titanium that is corrosion-resistant to the electrolyte, or this These alloys or alloys of these with other metals (for example, stainless steel) can be used. Furthermore, to prevent corrosion from the electrolyte, it is preferable to coat the components with nickel, aluminum, etc. Inside the battery can 602, the positive electrode, negative electrode, and separator are wound together to form a battery element. It is sandwiched between a pair of opposing insulating plates 608 and 609. Furthermore, a battery element is provided. The inside of the battery can 602 is filled with a non-aqueous electrolyte (not shown). The non-aqueous electrolyte is A battery similar to a coin-type rechargeable battery can be used.

[0256] The positive electrode 604 and the negative electrode 606 are manufactured in the same manner as the positive and negative electrodes of the thin battery described above. This is sufficient. Also, since the positive and negative electrodes used in cylindrical storage batteries are wound, both sides of the current collector It is preferable to form the active material on the surface. The positive electrode 604 has a positive electrode terminal (positive electrode current collector lead) 60 3 is connected, and the negative terminal (negative current collector lead) 607 is connected to the negative terminal 606. Positive terminal Both the sub-terminal 603 and the negative terminal 607 can be made of metal materials such as aluminum. The positive terminal 603 is connected to the safety valve mechanism 612, and the negative terminal 607 is connected to the bottom of the battery can 602. They are resistance welded. The safety valve mechanism 612 has a PTC element (Positive Temperature) The positive electrode cap 601 is electrically connected via the coefficient 611. It is connected. The safety valve mechanism 612 activates when the rise in the internal pressure of the battery exceeds a predetermined threshold. This disconnects the electrical connection between the electrode cap 601 and the positive electrode 604. Also, the PTC element... Child 611 is a thermosensitive resistance element whose resistance increases when the temperature rises, and as the resistance increases... This prevents abnormal heat generation by limiting the current. The PTC element contains barium titanate. BaTiO3-based semiconductor ceramics can be used.

[0257] When winding electrodes, such as in a cylindrical storage battery as shown in Figure 14, large stresses are placed on the electrodes during winding. Large stresses act upon it. Also, when the electrode winding is housed in the casing, the electrode is always subjected to the winding axis. A stress acts outward. Even if a large stress acts on the electrode in this way, the active material This prevents the material from cleaving.

[0258] In this embodiment, coin-type, cylindrical, and thin-type rechargeable batteries are shown. However, various types of batteries, such as sealed batteries and prismatic batteries, can be used. Furthermore, a structure in which multiple positive electrodes, negative electrodes, and separators are stacked, positive electrodes, negative electrodes, and separators The structure may also be one in which the data is wound. For example, other examples of storage batteries are shown in Figures 15 to 19. vinegar.

[0259] <Example of battery configuration> Figures 15 and 16 show examples of the configuration of a thin storage battery. The wound body 99 shown in Figure 15(A) 3 has a negative electrode 994, a positive electrode 995, and a separator 996.

[0260] The wound body 993 has the negative electrode 994 and the positive electrode 995 overlapping with the separator 996 in between. The laminated sheets are stacked and then wound up. This wound body 993 is placed in a rectangular sealed container. By covering it with a material, a rectangular secondary battery is created.

[0261] The number of layers in the stack consisting of the negative electrode 994, positive electrode 995, and separator 996 is required. The design should be appropriate depending on the capacitance and element volume. The negative electrode 994 is connected to the lead electrode 997 and One end of electrode 998 is connected to a negative electrode current collector (not shown), and positive electrode 995 is connected to a lead The electrode 997 and the other lead electrode 998 are connected to a positive electrode current collector (not shown). .

[0262] The storage battery 990 shown in Figures 15(B) and 15(C) is enclosed by a film 981. The space formed by bonding the film 982 having a recess to the above by heat-pressing or the like This houses the wound body 993 described above. The wound body 993 contains the lead electrode 997 and It has a hard electrode 998 and electrolysis occurs inside the film 981 and the film 982 which has a recess. It is impregnated with liquid.

[0263] Film 981 and film 982 having a recess are made of a metal material such as aluminum. Materials and resins can be used. Film 981 and film 982 having recesses If a resin material is used as the material, when an external force is applied, the film 981 and the recess will be affected. The film 982 having the property can be deformed, and a flexible storage battery can be manufactured. It is possible.

[0264] Furthermore, Figures 15(B) and 15(C) show examples where two films are used. By folding a single film, a space is formed, and the aforementioned wound body 9 is placed in that space. You may store 93.

[0265] Furthermore, by using resin materials for the outer casing and sealing container of the thin battery, flexibility can be increased. It is possible to manufacture an energy storage device. However, the outer casing and sealing container must be made of resin material. In this case, the parts that connect to the outside shall be made of conductive material.

[0266] For example, Figure 16 shows an example of another thin, flexible battery. Figure 16(A) shows the wound body 9 Since 93 is identical to the one shown in Figure 15(A), a detailed explanation will be omitted. .

[0267] The storage battery 990 shown in Figures 16(B) and 16(C) is located inside the outer casing 991 as described above. This houses the wound body 993. The wound body 993 contains the lead electrode 997 and lead It has an electrode 998 and is impregnated with an electrolyte inside the outer casings 991 and 992. Outer casing 991, 992 can be made of metal materials such as aluminum or resin materials. If resin material is used as the material for 991 and 992, when an external force is applied, the outer casing 9 By deforming 91 and 992, a flexible, thin storage battery can be fabricated. ru.

[0268] An electrode containing an active material according to one aspect of the present invention is used in a flexible, thin storage battery. Furthermore, even if stress is applied to the electrodes by repeatedly bending the thin battery, This prevents the material from cleaving.

[0269] Therefore, using an active material in which at least a portion of the cleavage surface is covered with graphene as an electrode... This makes it possible to suppress the drop in battery voltage and the decrease in discharge capacity. This can improve the battery's cycle characteristics during charging and discharging.

[0270] <Example of an energy storage system structure> Furthermore, an example of the structure of an energy storage system will be explained using Figures 17 to 19. An electrical system refers to, for example, equipment equipped with an energy storage device.

[0271] Figures 17(A) and 17(B) show external views of the energy storage system. The system comprises a circuit board 900 and a storage battery 913. The storage battery 913 has a label 91 A 0 is attached. Furthermore, as shown in Figure 17(B), the energy storage system has terminal 951 and It has terminal 952, antenna 914, and antenna 915.

[0272] The circuit board 900 has terminal 911 and circuit 912. Terminal 911 is connected to terminal 95 1. It is connected to terminal 952, antenna 914, antenna 915, and circuit 912. Oh, multiple terminals 911 are provided, and each of the multiple terminals 911 is a control signal input terminal, a power supply terminal, etc. It can also be used as a terminal, etc.

[0273] Circuit 912 may be provided on the back surface of circuit board 900. Note that antenna 914 And the antenna 915 is not limited to a coil shape, but may be, for example, linear or plate-shaped. Planar antenna, aperture antenna, traveling wave antenna, EH antenna, magnetic field antenna, induction An antenna such as an electrostatic antenna may be used. Alternatively, antenna 914 or antenna 91 5 may be a flat conductor. This flat conductor functions as one of the conductors for electric field coupling. This is possible. In other words, as one of the two conductors of the capacitor, Antenna 914 or antenna 915 may be activated. This will generate an electromagnetic field and a magnetic field. Furthermore, it is also possible to exchange power using an electric field.

[0274] The line width of antenna 914 is preferably larger than the line width of antenna 915. This allows for a greater amount of power to be received by antenna 914.

[0275] The energy storage system has a layer 9 between antennas 914 and 915 and the battery 913. It has 16. Layer 916 can shield electromagnetic fields, for example, from a storage battery 913. It has the ability to do so. For layer 916, for example, a magnetic material can be used.

[0276] Note that the structure of the energy storage system is not limited to the structure shown in Figure 17.

[0277] For example, as shown in Figures 18(A-1) and 18(A-2), Figure 17(A) and In the battery 913 shown in Figure 17(B), antennas are provided on each of the two opposing sides. This is also acceptable. Figure 18(A-1) is an external view of the pair of surfaces as seen from one side, and Figure 1 8(A-2) is an external view of the pair of surfaces as seen from the other side. Note that Figure 17(A) And for the same parts as the energy storage system shown in Figure 17(B), see Figures 17(A) and 1 The explanation of the energy storage system shown in 7(B) can be used as appropriate.

[0278] As shown in Figure 18(A-1), a layer 916 is sandwiched between one of the pair of surfaces of the storage battery 913. An incubator 914 is provided, and as shown in Figure 18(A-2), on the other side of the battery 913 An antenna 915 is provided on one side, with layer 917 in between. Layer 917 is, for example, connected to a storage battery 913. It has the function of shielding electromagnetic fields. For layer 917, for example, a magnetic material is used. It is possible to be there.

[0279] By adopting the above structure, the size of both antenna 914 and antenna 915 can be increased. It is possible to hear.

[0280] Alternatively, as shown in Figures 18(B-1) and 18(B-2), Figure 17(A) and Of the battery 913 shown in Figure 17(B), each of the two opposing sides has a different antenna. It may be provided. Figure 18(B-1) is an external view of the pair of surfaces as seen from one side. Figure 18(B-2) is an external view of the pair of surfaces as seen from the other side. Note that Figure 17( For the same parts as the energy storage system shown in A) and Figure 17(B), see Figure 17(A) and The explanation of the energy storage system shown in Figure 17(B) can be used as appropriate.

[0281] As shown in Figure 18(B-1), a layer 916 is sandwiched between one of the pair of surfaces of the storage battery 913. An antenna 914 and an antenna 915 are provided, and as shown in Figure 18(A-2), the storage battery An antenna 918 is provided on the other side of the pair of faces of 913, with layer 917 in between. Antenna 91 8, for example, has the function of being able to communicate data with external devices. Antenna 91 For example, antennas with shapes applicable to antennas 914 and 915 can be applied to 8. This is possible. It is a communication method between the energy storage system and other devices via antenna 918. This involves applying response methods that can be used between the energy storage system and other devices, such as NFC. It is possible.

[0282] Alternatively, as shown in Figure 19(A), the storage battery 91 shown in Figures 17(A) and 17(B) A display device 920 may be provided at 3. The display device 920 is connected to terminal 911 via terminal 919. It is electrically connected to the display device 920. It is not necessary. Furthermore, the same parts as the energy storage system shown in Figures 17(A) and 17(B) In this regard, the explanation of the energy storage system shown in Figures 17(A) and 17(B) can be appropriately referenced.

[0283] The display device 920 may display, for example, an image indicating whether or not it is charging, an image indicating the amount of stored power, etc. It may be displayed. The display device 920 may be, for example, electronic paper, liquid crystal display device, etc. A trollescent (also known as EL) display device can be used. For example, an electronic paper By using a supercharger, the power consumption of the display device 920 can be reduced.

[0284] Alternatively, as shown in Figure 19(B), the storage battery 91 shown in Figures 17(A) and 17(B) A sensor 921 may be provided at 3. The sensor 921 receives power from terminal 911 via terminal 922. It is electrically connected. Note that it is the same part as the energy storage system shown in Figures 17(A) and 17(B). For details, please refer to the explanation of the energy storage system shown in Figures 17(A) and 17(B) as appropriate. Cut.

[0285] Examples of sensors 921 include force, displacement, position, velocity, acceleration, angular velocity, rotational speed, and distance. Separation, light, liquid, magnetism, temperature, chemical substances, sound, time, hardness, electric field, electric current, voltage, power, radiation Use a device that includes functions for measuring radiation, flow rate, humidity, gradient, vibration, odor, or infrared radiation. This is possible. By providing the sensor 921, for example, the environment in which the energy storage system is located can be detected. It is also possible to detect data indicating this (such as temperature) and store it in the memory within circuit 912. .

[0286] The battery and energy storage system shown in this embodiment use electrodes according to one aspect of the present invention. Therefore, the capacity of batteries and energy storage systems can be increased. Energy density can be increased. Reliability can be improved. Furthermore, lifespan can be extended. It can be done.

[0287] This embodiment can be implemented in appropriate combination with other embodiments.

[0288] (Embodiment 3) This embodiment describes an example of mounting a flexible storage battery in an electronic device.

[0289] Figure 20 shows an example of mounting the flexible battery described in Embodiment 2 into an electronic device. Electronic devices that utilize energy storage devices with a flexible shape include, for example, television equipment. Televisions (also called televisions or television receivers), monitors for computers, digital cameras, etc. Cameras, digital video cameras, digital photo frames, mobile phones (mobile phones, portable cameras) (Also known as mobile phone devices), portable game consoles, personal digital assistants, sound playback devices, pachinko machines, etc. Examples include large game consoles.

[0290] Furthermore, energy storage devices with flexible shapes can be installed in the interior or exterior walls of houses and buildings, or in automated systems. It can also be integrated to conform to the curved surfaces of the car's interior or exterior.

[0291] Figure 20(A) shows an example of a mobile phone. The mobile phone 7400 has a housing 740 In addition to the display unit 7402 incorporated into 1, there are also operation buttons 7403, an external connection port 7404, It is equipped with speaker 7405, microphone 7406, etc. Note that the mobile phone 7400 is a storage It has an electrical device 7407.

[0292] Figure 20(B) shows the mobile phone 7400 in a curved state. When 00 is deformed by an external force and the whole thing is bent, the power storage device located inside it The 7407 is also bent. Figure 20 shows the state of the bent energy storage device 7407 at that time. As shown in C), the energy storage device 7407 is a thin battery. The energy storage device 7407 is bent. It is fixed in place. Furthermore, the energy storage device 7407 is electrically connected to the current collector 7409. It has a 7408 electrode.

[0293] Figure 20(D) shows an example of a bangle-type display device. The portable display device 7100 is It comprises a housing 7101, a display unit 7102, operation buttons 7103, and a power storage device 7104. Figure 20(E) also shows the state of the bent energy storage device 7104. The energy storage device 7104 is When worn on the user's arm in a bent state, the casing deforms, causing part of the power storage device 7104 to be damaged. The curvature of the curve changes across the entire curve. Note that the degree of curvature at any point in the curve is the radius of the corresponding circle. The value expressed as is the radius of curvature, and the reciprocal of the radius of curvature is called the curvature. Specifically, the half of the radius of curvature A portion of the main surface of the housing or energy storage device 7104, within the range of 40 mm to 150 mm in diameter Or the whole thing changes. The radius of curvature on the main surface of the energy storage device 7104 is 40 mm or more 15 High reliability can be maintained within a range of 0 mm or less.

[0294] Figure 20(F) shows an example of a wristwatch-type personal information terminal. Personal information terminal 7200 The components are: housing 7201, display unit 7202, band 7203, buckle 7204, and operation button 7 It is equipped with terminals 205 and input / output terminals 7206, etc.

[0295] The 7200 mobile information terminal offers mobile phone calls, email, document viewing and creation, music playback, and more. It can run various applications such as internet communication and computer games. Cut.

[0296] The display unit 7202 has a curved display surface, and displays information along the curved surface. It is possible to do so. In addition, the display unit 7202 is equipped with a touch sensor, and the screen can be touched with a finger or stylus. It can be operated by touching it. For example, icon 7 displayed on the display unit 7202 Touching 207 will launch the application.

[0297] The 7205 control button is used for time setting, as well as power on / off, wireless communication on, and more. Various functions such as operation, activation and deactivation of silent mode, and activation and deactivation of power saving mode. It can be made to hold. For example, the operating system built into the personal digital assistant 7200 The system also allows you to freely configure the function of the control button 7205.

[0298] Furthermore, the 7200 portable information terminal 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.

[0299] Furthermore, the portable information terminal 7200 is equipped with an input / output terminal 7206, and can connect to other information terminals. Data can be exchanged directly via this. Also, charging is possible via input / output terminal 7206. It can also perform electrical operations. Note that charging is done wirelessly without using input / output terminal 7206. You may go.

[0300] The display unit 7202 of the portable information terminal 7200 is equipped with an electrode member according to one aspect of the present invention for energy storage. It has a device. For example, the energy storage device 7104 shown in Figure 20(E) is housed in a casing 7201. It can be incorporated in a curved state internally, or in a state that allows it to be curved internally within the band 7203. can.

[0301] Figure 20(G) shows an example of an armband-type display device. The display device 7300 is a display unit The device has 7304 and has an energy storage device according to one aspect of the present invention. Furthermore, the display device 7300 is The display unit 7304 can also be equipped with a touch sensor, and it can also function as a portable information terminal. It is also possible to do so.

[0302] The display unit 7304 has a curved display surface, and displays are performed along the curved display surface. This is possible. In addition, the display device 7300 can display information via standardized short-range wireless communication. The situation can be changed.

[0303] Furthermore, the display device 7300 is equipped with input / output terminals and can be directly connected to other information terminals via connectors. It can exchange data. It can also be charged via its input / output terminals. Furthermore, charging may be performed wirelessly without using input / output terminals.

[0304] This embodiment can be implemented in appropriate combination with other embodiments.

[0305] (Embodiment 4) This embodiment shows an example of an electronic device that can be equipped with an energy storage device.

[0306] Figures 21(A) and 21(B) show an example of a foldable tablet device. The tablet terminal 9600 shown in Figures 21(A) and 21(B) has a housing 9630a, Housing 9630b, movable part 9640 connecting housing 9630a and housing 9630b, display unit 9 Display unit 9631 having 631a and display unit 9631b, display mode switching switch 96 26. Power switch 9627, power saving mode switch 9625, fastener 9629 It has an operating switch 9628. Figure 21(A) shows the tablet terminal 9600 opened. Figure 21(B) shows the state in which the tablet terminal 9600 is closed.

[0307] Furthermore, the tablet terminal 9600 stores inside the housings 9630a and 9630b. It has an electric body 9635. The electric body 9635 passes through the movable part 9640 and the housing 9630a and the housing It is provided across body 9630b.

[0308] The display unit 9631a can be partially designated as a touch panel area 9632a, and the display will Data can be entered by touching the operation key 9638. Note that the display unit 96 In 31a, as an example, one half of the area has a display-only function, and the other half of the area The area indicates a configuration having touch panel functionality, but is not limited to this configuration. Display unit 96 The entire area of ​​31a may also be configured to have touch panel functionality. For example, the display unit 9 The entire surface of 631a is used as a touch panel with keyboard buttons, and the display unit 9631b is displayed It can be used as a display screen.

[0309] In addition, in the display unit 9631b, similar to the display unit 9631a, one of the display units 9631b The area can be designated as the touch panel area 9632b. Also, the touch panel keyboard Touch the location where the display toggle button 9639 is displayed using your finger or stylus. This allows keyboard buttons to be displayed on the display unit 9631b.

[0310] Furthermore, simultaneously with respect to the touch panel area 9632a and the touch panel area 9632b You can also use touch input.

[0311] Additionally, the display mode switch 9626 changes the display orientation, such as portrait or landscape. You can switch between modes, such as switching between black and white and color displays. Power saving mode switching... The switch 9625 is used by the light sensor built into the tablet terminal 9600. The display brightness can be optimized according to the amount of ambient light at the time. (Tablet device) In addition to optical sensors, other sensors such as gyroscopes and accelerometers that detect tilt are also used. An output device may be built into the unit.

[0312] Furthermore, Figure 21(A) shows an example where the display area of ​​display unit 9631b and display unit 9631a are the same. However, this is not particularly limited, and one size may be different from the other. The quality of the display may also differ. For example, one display panel can provide a higher resolution display than the other. You can also use "ru".

[0313] Figure 21(B) shows the closed state, and the tablet terminal consists of a housing 9630 and a solar cell 9 633, it has a charge / discharge control circuit 9634 including a DC-DC converter 9636. As the power body 9635, a power storage body according to one aspect of the present invention is used.

[0314] Furthermore, since the tablet device 9600 is foldable, the casing 9630a can be folded in half when not in use. The casing 9630b can be folded so that it overlaps with the other casing. Therefore, the display unit 9631a and the display unit 9631b can be protected, thus the tablet terminal 9600 Durability can be increased. Furthermore, the energy storage body 9635 using the energy storage body according to one aspect of the present invention is It is flexible and its charge / discharge capacity does not easily decrease even after repeated bending and stretching. Therefore, reliability We can provide excellent tablet devices.

[0315] In addition, there are various other tablet devices, as shown in Figures 21(A) and 21(B). Features that display information (still images, videos, text images, etc.), calendar, date or time. Functions that display such information on the display unit, and touch input operations or editing of the information displayed on the display unit. It has features such as input functionality and the ability to control processing through various software (programs). It is possible.

[0316] The touch panel is powered by a solar cell 9633 mounted on the surface of the tablet device. It can be supplied to the display unit or the video signal processing unit, etc. The solar cell 9633 is It can be installed on one or both sides of the housing 9630, and efficiently charges the energy storage unit 9635. This configuration can be achieved. Furthermore, if a lithium-ion battery is used as the energy storage element 9635, This offers advantages such as the ability to miniaturize the device.

[0317] Furthermore, the configuration and operation of the charge / discharge control circuit 9634 shown in Figure 21(B) are shown in Figure 21. (C) shows a block diagram and provides an explanation. Figure 21(C) shows a solar cell 9633 and a power storage unit 96 35. DC-DC converter 9636, converter 9637, switch SW1 to SW3, The display unit 9631 is shown, along with the energy storage unit 9635, the DC-DC converter 9636, and Converter 9637, switches SW1 to SW3, and the charge / discharge control circuit 9 shown in Figure 21(B) This corresponds to the section for 634.

[0318] First, let's explain an example of how the solar cell 9633 operates when generating electricity using ambient light. The electricity generated by the solar cells is converted into a DC-DC converter to provide the voltage necessary to charge the 9635 energy storage unit. The converter 9636 performs voltage boosting or bucking. Then, the solar power is used to control the operation of the display unit 9631. When power from pond 9633 is used, switch SW1 is turned ON, and converter 963 In step 7, the voltage is increased or decreased to the required voltage for the display unit 9631. Also, the display unit 963 If you do not want to display in step 1, turn SW1 off and turn SW2 on to enable the storage unit 9635. The configuration should include charging capabilities.

[0319] While solar cell 9633 is shown as an example of a power generation method, it is not particularly limited to this method. Storage using other power generation methods such as piezoelectric elements (piezo elements) and thermoelectric elements (Peltier elements) The configuration may also involve charging the battery 9635. For example, power may be transmitted and received wirelessly (contactlessly). This includes contactless power transmission modules that charge via this method, as well as configurations that combine this with other charging methods. You may do so.

[0320] Figure 22 shows an example of another electronic device. In Figure 22, the display device 8000 is the present invention. This is an example of an electronic device using a power storage device 8004 according to one embodiment. Specifically, the display device 80 00 corresponds to a display device for receiving TV broadcasts, and consists of a housing 8001, a display unit 8002, and a speaker. It has part 8003, a power storage device 8004, etc. A power storage device 8004 according to one aspect of the present invention is It is located inside the enclosure 8001. The display device 8000 receives power from the commercial power supply. You can receive power from it, or you can use the power stored in the energy storage device 8004. Therefore, even when power cannot be supplied from the commercial power source due to a power outage or the like, according to one aspect of the present invention By using the energy storage device 8004 as an uninterruptible power supply, the display device 8000 can be used. Yes.

[0321] The display unit 8002 has light-emitting elements such as liquid crystal display devices and organic EL elements in each pixel. Optical devices, electrophoresis display devices, DMDs (Digital Micromirror Dev ice), PDP (Plasma Display Panel), FED (Field Semiconductor display devices such as Emission Displays can be used.

[0322] In addition to being used for receiving TV broadcasts, the display devices are also used for personal computers and for displaying advertisements. This includes all information display devices.

[0323] In Figure 22, the fixed lighting device 8100 is a power storage device 8 according to one aspect of the present invention. This is an example of an electronic device using 103. Specifically, the lighting device 8100 has a housing 8101, It has a light source 8102, a power storage device 8103, etc. In Figure 22, the power storage device 8103 is located in the housing 8 For example, consider the case where 101 and the light source 8102 are installed inside the ceiling 8104. Although shown, the energy storage device 8103 may be located inside the housing 8101. The device 8100 can receive power from the commercial power supply, or from the energy storage device 8103. It is also possible to use stored power. Therefore, in the event of a power outage, etc., power supply from commercial power source Even when it is not possible to receive a power supply, the energy storage device 8103 according to one aspect of the present invention can be used as an uninterruptible power supply. This makes it possible to use the lighting device 8100.

[0324] In Figure 22, a fixed lighting device 8100 installed on the ceiling 8104 is shown as an example. However, in one aspect of the present invention, the energy storage device can be used not only on the ceiling 8104, but also on the side walls 8105, floor, etc. It can also be used in fixed lighting devices installed in windows such as 8106 and 8107, and also in tables It can also be used in overhead lighting fixtures and other applications.

[0325] Furthermore, the light source 8102 can use an artificial light source that artificially obtains light using electricity. Yes, it is possible. Specifically, this includes discharge lamps such as incandescent light bulbs and fluorescent lamps, and LEDs and organic EL elements. Optical elements are an example of the artificial light sources mentioned above.

[0326] In Figure 22, the air conditioner having an indoor unit 8200 and an outdoor unit 8204 is This is an example of an electronic device using the energy storage device 8203 according to one aspect of the present invention. Specifically, the room The internal unit 8200 includes a housing 8201, an air outlet 8202, a power storage device 8203, etc. (Figure 22) The example given is that the energy storage device 8203 is installed in the indoor unit 8200, The electrical device 8203 may be installed on the outdoor unit 8204. Alternatively, it may be installed on the indoor unit 8200 and the room Both outdoor units 8204 may be equipped with energy storage devices 8203. - It can receive power from the commercial power supply, or stored in the energy storage device 8203 Electricity can also be used. In particular, both the indoor unit 8200 and the outdoor unit 8204 are equipped with energy storage devices 8 If 203 is installed, when power cannot be supplied from the commercial power source due to a power outage, etc. However, by using the energy storage device 8203 according to one aspect of the present invention as an uninterruptible power supply, Conditioner can be used.

[0327] Figure 22 shows a separate-type air conditioner consisting of an indoor unit and an outdoor unit. The example shown is an integrated air conditioner that has both the indoor and outdoor unit functions in a single housing. A power storage device according to one aspect of the present invention can also be used as the conditioner.

[0328] In Figure 22, the electric refrigerator 8300 is a power storage device 8304 according to one aspect of the present invention. This is an example of an electronic device using [a specific component]. Specifically, the electric refrigerator 8300 has a casing 8301, It has a refrigerator door 8302, a freezer door 8303, an energy storage device 8304, etc. In Figure 22, The energy storage device 8304 is located inside the casing 8301. The electric refrigerator 8300 is It can also receive power from the commercial power supply, or the power stored in the energy storage device 8304 It is also possible to use this. Therefore, if power cannot be supplied from the commercial power source due to a power outage, etc. Even at times, by using the energy storage device 8304 according to one aspect of the present invention as an uninterruptible power supply, The 8300 refrigerator / freezer will become available for use.

[0329] Of the electronic devices mentioned above, high-frequency heating devices such as microwave ovens and electric rice cookers are included. Sub-devices require high power for short periods. Therefore, they need to supplement the power that cannot be supplied by the commercial power supply. By using an energy storage device according to one aspect of the present invention as an auxiliary power source to assist, electronic equipment This prevents the commercial power circuit breaker from tripping when using it.

[0330] Furthermore, during periods when electronic devices are not in use, especially the total amount of electricity that can be supplied by the commercial power source... Of these, during the time periods when the proportion of electricity actually used (called the electricity usage rate) is low, storage By storing electricity in the electrical equipment, the rate of electricity use outside of the above-mentioned time period can be suppressed. It is possible. For example, in the case of the electric refrigerator 8300, when the temperature is low, the refrigerator door 83 02. At night when the freezer door 8303 is not opened or closed, power is supplied to the energy storage device 8304. Store. Then, as the temperature rises, the refrigerator door 8302 and the freezer door 8303 are opened and closed. During the daytime, by using the energy storage device 8304 as an auxiliary power source, daytime electricity usage The rate can be kept low.

[0331] This embodiment can be implemented in appropriate combination with other embodiments.

[0332] (Embodiment 5) This embodiment shows an example in which a power storage device is installed in a vehicle.

[0333] Furthermore, when a battery storage device is installed in a vehicle, hybrid electric vehicles (HEVs) and electric vehicles (EVs) or next-generation clean energy vehicles such as plug-in hybrid vehicles (PHEVs) It can be expressed.

[0334] Figure 23 illustrates a vehicle using one embodiment of the present invention. The automobile shown in Figure 23(A) The 8400 is an electric vehicle that uses an electric motor as its power source for propulsion. It is possible to appropriately select and use an electric motor and an engine as the power source for propulsion. This is a hybrid vehicle. By using one aspect of the present invention, a vehicle with a long driving range can be realized. It is possible. Furthermore, the automobile 8400 has a power storage device. The power storage device is an electric motor In addition to driving the 8406, it also powers the headlights 8401 and interior lights (not shown), etc. It can supply power to the light-emitting device.

[0335] Furthermore, the energy storage device is used for the speedometer, tachometer, and other displays of the 8400 automobile. It can supply power to the display device. In addition, the energy storage device is the navigation system of the automobile 8400. It can supply power to semiconductor devices such as gate systems.

[0336] The automobile 8500 shown in Figure 23(B) plugs into the energy storage device of the automobile 8500. It can be charged by receiving power from an external charging facility using methods such as contactless power supply. It can be done. Figure 23(B) shows the ground-mounted charging device 8021 being mounted on the automobile 8500. This shows the state in which the energy storage device 8024 is being charged via cable 8022. Therefore, charging methods and connector specifications are subject to the standards of CHAdeMO (registered trademark) and Combo, etc. This can be done as appropriate. The charging device 8021 is a charging station installed in a commercial facility. However, it is also fine to use a household power supply. For example, plug-in technology allows external power to be supplied. The power supply can be used to charge the energy storage device 8024 installed in the automobile 8500. Charging is performed by converting AC power to DC power via a conversion device such as an AC / DC converter. It is possible.

[0337] Although not shown in the diagram, a power receiving device is mounted on the vehicle, and power is supplied wirelessly from a ground-based power transmission device. It can also be charged by supplying power. In this contactless power supply method, the power transmission equipment is installed on the road or exterior wall. By incorporating this, charging can be performed not only when the vehicle is stopped but also while it is in motion. The electric system may be used to transmit and receive power between vehicles. Furthermore, the exterior of the vehicle Solar panels may be installed to charge the energy storage device when the vehicle is stopped or in motion. Electromagnetic induction and magnetic resonance methods can be used to supply power in this environment.

[0338] According to one aspect of the present invention, the cycle characteristics of the energy storage device are improved, and its reliability is enhanced. It is possible to do so. Furthermore, according to one aspect of the present invention, the characteristics of the energy storage device can be improved. Therefore, the energy storage device itself can be made smaller and lighter. This contributes to reducing the vehicle's weight, thus improving its driving range. The installed energy storage device can also be used as a power source other than the vehicle. In this case, the power demand This allows us to avoid using commercial power during peak hours.

[0339] This embodiment can be implemented in appropriate combination with other embodiments.

[0340] (Embodiment 6) A battery that can be used in combination with a battery cell containing the materials described in the above embodiment. Control unit (Battery Management Unit: BMU), and the power For transistors suitable for the circuits constituting the pond control unit, refer to Figures 24 to 30. This will be explained. In this embodiment, in particular, the power of a storage device having battery cells connected in series Let me explain the pond control unit.

[0341] When multiple battery cells connected in series are repeatedly charged and discharged, between each battery cell... As a result, variations occur in charge and discharge characteristics, causing the capacity (output voltage) of each battery cell to differ. In a series connection of multiple battery cells, the total discharge capacity is less than that of the smallest battery cell. It depends on the capacity of each battery cell. If there is variation in the capacity of each battery cell, the overall capacity during discharge will be smaller. Furthermore, charging based on a battery cell with a smaller capacity may result in insufficient charging. Charging based on a larger capacity battery cell may lead to overcharging.

[0342] Therefore, the battery control unit of an energy storage device having battery cells connected in series is unable to charge. It has a function to equalize the capacity variations between battery cells, which can cause problems such as overcharging. Circuit configurations to equalize the capacitance variations between components include resistor methods, capacitor methods, or inverter methods. There are duct-type methods, but here we use a transistor with a small off-current to handle capacitance variations. I will explain by giving an example of a circuit configuration that can provide these features.

[0343] As a transistor with a low off-current, a transistor having an oxide semiconductor in the channel formation region is... A transistor (OS transistor) is preferred. An OS transistor with a small off-current is used for energy storage. By using it in the circuit configuration of the device's battery control unit, the amount of charge leaking from the battery is reduced. This can suppress the decrease in capacity over time.

[0344] The oxide semiconductor used in the channel formation region is In-M-Zn oxide (where M is Ga, Sn (Y, Zr, La, Ce, or Nd) are used. Used to form oxide semiconductor films. In the target, the atomic ratio of the metal elements is In:M:Zn = x1:y1:z1. and 、 x1 / y1 is between 1 / 3 and 6, and moreover, between 1 and 6, and z1 / y1 is It is preferable that z1 / y1 is between 1 / 3 and 6, and more preferably between 1 and 6. By setting the value to 6 or less, the CAAC-OS film is more easily formed as an oxide semiconductor film. .

[0345] Now, let's discuss the CAAC-OS membrane.

[0346] CAAC-OS film is an oxide semiconductor film having multiple c-axis oriented crystalline regions. .

[0347] Transmission Electron Microscope (TEM) A composite image of the bright-field image and diffraction pattern of the CAAC-OS film was obtained using an optical scope. By observing (also known as high-resolution TEM images), multiple crystalline regions can be identified. On the other hand, high-resolution TEM images also clearly show the boundaries between crystal parts, i.e., grain boundaries. It is not possible to confirm the boundary (also called the boundary). Therefore, the CAAC-OS membrane is This means that a decrease in electron mobility due to grain boundaries is less likely to occur.

[0348] When observing a high-resolution TEM image of the cross-section of the CAAC-OS film from a direction approximately parallel to the sample surface, In the crystalline region, it can be confirmed that the metal atoms are arranged in layers. Each layer of metal atoms is This reflects the unevenness of the surface (also called the surface to be formed) or the upper surface of the CAAC-OS film. It has a specific shape and is arranged parallel to the surface or top surface of the CAAC-OS film to be formed.

[0349] On the other hand, a high-resolution TEM image of the CAAC-OS film plane was observed from a direction approximately perpendicular to the sample surface. Then, it was confirmed that the metal atoms in the crystalline region are arranged in a triangular or hexagonal shape. Yes, it is possible. However, no regularity is observed in the arrangement of metal atoms between different crystalline regions.

[0350] X-ray diffraction (XRD) of CAAC-OS film When structural analysis is performed using the instrument, for example, CAAC-OS having InGaZnO4 crystals is found. Out-of-plane analysis of the film showed a peak at a diffraction angle (2θ) of around 31°. This peak may appear. This peak is attributed to the (009) plane of the InGaZnO4 crystal. Therefore, the crystals of the CAAC-OS film have c-axis orientation, and the c-axis is on the surface to be formed or on the upper surface. It can be confirmed that it is facing in a nearly vertical direction.

[0351] Furthermore, the out-of-plane CAAC-OS film having InGaZnO4 crystals Analysis using this method revealed that in addition to the peak near 2θ = 31°, there is also a peak near 2θ = 36°. In some cases, this may occur. Peaks near 2θ of 36° indicate c-axis orientation in a portion of the CAAC-OS film. This indicates the presence of crystals that do not possess properties. The CAAC-OS film has a 2θ of approximately 31°. It is preferable that a peak is shown and that no peak is shown near 36° for 2θ.

[0352] CAAC-OS films are oxide semiconductor films with low impurity concentrations. The impurities include hydrogen and carbon. These are elements other than the main components of oxide semiconductor films, such as silicon and transition metal elements. In particular, silicon Elements such as condensate, which have a stronger bonding force with oxygen than the metal elements that make up oxide semiconductor films, are acidic. By removing oxygen from the oxide semiconductor film, the atomic arrangement of the oxide semiconductor film is disrupted, reducing its crystallinity. This is a contributing factor. Also, heavy metals such as iron and nickel, argon, and carbon dioxide have a high atomic ratio. Because of its large diameter (or molecular radius), when it is contained within an oxide semiconductor film, the oxide semiconductor film This disrupts the atomic arrangement and reduces crystallinity. Pure substances can act as carrier traps or carrier sources.

[0353] Furthermore, CAAC-OS films are oxide semiconductor films with a low defect level density. For example, oxidation Oxygen vacancies in semiconductor films can act as carrier traps or capture hydrogen. This can sometimes become a source of carrier transmission.

[0354] A low impurity concentration and low defect level density (few oxygen vacancies) are referred to as high-purity intrinsic or This is essentially called high-purity intrinsic. Oxide semiconductors that are high-purity intrinsic or substantially high-purity intrinsic. Because membranes have fewer carrier sources, they can have lower carrier densities. Therefore The transistor using the oxide semiconductor film exhibits electrical characteristics such as a negative threshold voltage. It rarely becomes (also called normally-on). Also, it is of high purity and is essentially high purity. Intrinsically pure oxide semiconductor films have few carrier traps. Therefore, the oxide semiconductor film Transistors using conductive films exhibit less variation in electrical characteristics and are highly reliable. Yes. Furthermore, the charge trapped in the carrier trap of the oxide semiconductor film requires time to be released. This process can last for a long time, sometimes behaving as if it were a fixed charge. Therefore, the impurity concentration... Transistors using oxide semiconductor films with high defect level density have unstable electrical properties. This can sometimes happen.

[0355] Furthermore, transistors using CAAC-OS films exhibit electrical properties when irradiated with visible light or ultraviolet light. Sexual variation is small.

[0356] OS transistors are transistors that have silicon in the channel formation region (Si Because it has a larger band gap compared to a transistor, dielectric breakdown when a high voltage is applied is It is unlikely to occur. When battery cells are connected in series, a voltage of several hundred volts will be generated, In energy storage devices, the circuit configuration of the battery control unit applied to such battery cells includes the following: It is suitable to construct it using the OS transistors described above.

[0357] Figure 24 shows an example of a block diagram of an energy storage device. The energy storage device BT00 shown in Figure 24 is Terminal pair BT01, terminal pair BT02, switching control circuit BT03, switching circuit BT 04, switching circuit BT05, transformer control circuit BT06, transformer circuit BT07, in series It has a battery section BT08 which includes a plurality of connected battery cells BT09.

[0358] Furthermore, in the energy storage device BT00 shown in Figure 24, terminal pair BT01 and terminal pair BT02 are connected. Switching control circuit BT03, switching circuit BT04, switching circuit BT05, and transformer control The part consisting of the control circuit BT06 and the transformer circuit BT07 is called the battery control unit. It can be done.

[0359] The switching control circuit BT03 controls the operation of switching circuits BT04 and BT05. It controls the following. Specifically, the switching control circuit BT03 measures each battery cell BT09 and Based on the voltage, the battery cells to be discharged (discharge battery cell group) and the battery cells to be charged (charge battery cell group) are selected. Determine the battery cell group.

[0360] Furthermore, the switching control circuit BT03 controls the determined group of discharged battery cells and the rechargeable battery cells. Based on the group, control signals S1 and S2 are output. Control signal S1 is a switching signal. The signal is output to circuit BT04. This control signal S1 connects terminal pair BT01 and the group of discharge battery cells. This is a signal that controls the switching circuit BT04 to connect. Also, the control signal S2 is, The signal is output to the switching circuit BT05. This control signal S2 is connected to the terminal pair BT02 and the rechargeable battery. This is a signal that controls the switching circuit BT05 to connect the group of elements.

[0361] Furthermore, the switching control circuit BT03 is connected to the switching circuit BT04, the switching circuit BT05, And based on the configuration of the transformer circuit BT07, between the terminal pair BT01 and the group of discharge battery cells, The terminals of the BT02 and the group of rechargeable battery cells are controlled to connect terminals of the same polarity. The system generates the official signal S1 and the control signal S2.

[0362] This section describes the operation of the switching control circuit BT03 in detail.

[0363] First, the switching control circuit BT03 measures the voltage of each of the multiple battery cells BT09. Then, the switching control circuit BT03, for example, switches the battery cell BT09 with a voltage above a predetermined threshold. High-voltage battery cells (high-voltage cells), BT09 battery cells with a voltage below a predetermined threshold, and low-voltage It is determined to be a battery cell (low-voltage cell).

[0364] Furthermore, various methods are used to determine whether a cell is high-voltage or low-voltage. This is possible. For example, the switching control circuit BT03 is the most important among the multiple battery cells BT09. Each battery cell BT09 is measured using the voltage of the highest or lowest voltage battery cell as a reference. It may also be possible to determine whether 09 is a high-voltage cell or a low-voltage cell. In this case, the switching control circuit BT0 Step 3 determines whether the voltage of each battery cell BT09 is above a predetermined percentage of the reference voltage. By doing so, it is possible to determine whether each battery cell BT09 is a high-voltage cell or a low-voltage cell. Then, based on this determination, the switching control circuit BT03 switches between the discharge battery cell group and the charging battery group. Determine the battery cell group.

[0365] Note that within multiple BT09 battery cells, high-voltage and low-voltage cells are mixed in various states. It is possible. For example, the switching control circuit BT03 is used when high-voltage cells and low-voltage cells are mixed together. The portion where the most high-voltage cells are connected in series is designated as the discharge battery cell group. The switching control circuit BT03 charges the portion where the most low-voltage cells are connected in series. This is a group of battery cells. Furthermore, the switching control circuit BT03 is used for batteries that are close to being overcharged or over-discharged. Cell BT09 is preferentially selected as either a discharge battery cell group or a recharge battery cell group. That's good too.

[0366] Here, an example of the operation of the switching control circuit BT03 in this embodiment will be explained using Figure 25. To clarify, Figure 25 is a diagram illustrating an example of the operation of the switching control circuit BT03. For the sake of explanation, Figure 25 shows an example where four BT09 battery cells are connected in series. explain.

[0367] First, in the example shown in Figure 25(A), the voltages of battery cells a through d are defined as voltages Va through Vd. This shows the case where Va=Vb=Vc>Vd. In other words, three consecutive high Voltage cells a through c and one low-voltage cell d are connected in series. In this case, switching The control circuit BT03 determines three consecutive high-voltage cells a to c as a discharge battery cell group. The switching control circuit BT03 also determines the low-voltage cell d as part of the rechargeable battery cell group. ru.

[0368] Next, the example in Figure 25(B) shows the case where Vc > Va = Vb >> Vd. In other words, two consecutive low-voltage cells a and b, one high-voltage cell c, and one over-discharge A nearby low-voltage cell d is connected in series. In this case, the switching control circuit BT03 The high-voltage cell c is determined to be the discharge battery cell group. Furthermore, the switching control circuit BT03 is... Because low-voltage cell d is close to over-discharge, instead of using the two consecutive low-voltage cells a and b, Voltage cell d is given priority as the group of rechargeable battery cells.

[0369] Finally, the example in Figure 25(C) shows the case where Va > Vb = Vc = Vd. In other words, one high-voltage cell a is connected in series with three consecutive low-voltage cells b through d. In this case, the switching control circuit BT03 switches the high-voltage cell a to the discharge battery cell group. The decision is made. Furthermore, the switching control circuit BT03 charges three consecutive low-voltage cells b through d. This will be determined as a group of battery cells.

[0370] The switching control circuit BT03 is determined as shown in the examples in Figures 25(A) to (C) above. Based on the results, information indicating the group of discharge battery cells to which the switching circuit BT04 is connected is set. The signal control S1 and information indicating the group of rechargeable battery cells to which the switching circuit BT05 is connected The set control signal S2 is sent to switching circuits BT04 and BT05. Output each separately.

[0371] The above is a detailed explanation of the operation of the switching control circuit BT03.

[0372] The switching circuit BT04 responds to the control signal S1 output from the switching control circuit BT03. Then, the destination of the terminal pair BT01 is determined by the switching control circuit BT03, which is the discharge battery. Set it to a group of cells.

[0373] Terminal pair BT01 is composed of the paired terminals A1 and A2. Switching circuit BT0 4. Of these terminals A1 and A2, one is the upstream (high) of the group of discharged battery cells. Connect the positive terminal of battery cell BT09 located on the potential side, and the other end within the group of discharge battery cells. By connecting to the negative terminal of the battery cell BT09, which is located furthest downstream (low potential side), the terminal Set the connection destination for the child BT01. Note that the switching circuit BT04 is set to control signal S1. The location of the discharge battery cells can be recognized using the collected information.

[0374] The switching circuit BT05 responds to the control signal S2 output from the switching control circuit BT03. Then, the connection destination of terminal pair BT02 is determined by the switching control circuit BT03 to the rechargeable battery. Set it to a group of cells.

[0375] Terminal pair BT02 consists of the paired terminals B1 and B2. Switching circuit BT0 5. Of these terminals B1 and B2, one is the upstream (high) of the rechargeable battery cell group. Connect the positive terminal of battery cell BT09 located on the potential side, and the other end within the group of rechargeable battery cells. By connecting to the negative terminal of the battery cell BT09, which is located furthest downstream (low potential side), the terminal Set the connection destination for the child BT02. Note that the switching circuit BT05 is set to control signal S2. The information obtained can be used to recognize the location of the battery cell group.

[0376] Figures 26 and 26 show circuit diagrams illustrating example configurations of switching circuits BT04 and BT05. This is shown in 27.

[0377] In Figure 26, the switching circuit BT04 consists of multiple transistors BT10 and bus BT11 It also has BT12. Bus BT11 is connected to terminal A1. Terminal 12 is connected to terminal A2. Multiple transistors BT10 are either source or drain. One of them is connected to buses BT11 and BT12 alternately, one after the other. Furthermore, the source or drain of each of the multiple transistors BT10 is connected to two adjacent ones. It is connected between the BT09 battery cells.

[0378] Of the multiple transistors BT10, the transistor BT10 located at the very top The other end of the source or drain is the positive terminal of battery cell BT09, which is located at the uppermost part of battery section BT08. It is connected to the polarity terminal. Also, it is located at the downstream end of the multiple transistors BT10. The source or drain of transistor BT10 is located at the furthest downstream end of the battery section BT08. It is connected to the negative terminal of the BT09 battery cell.

[0379] The switching circuit BT04 provides control signals S1 to the gates of multiple transistors BT10. Accordingly, one of the multiple transistors BT10 connected to bus BT11, and bus One of the multiple transistors BT10 connected to BT12 is set to conduction. This connects the discharge battery cell group and the terminal pair BT01. The positive terminal of battery cell BT09, which is located in the uppermost part of the cell group, is terminal A1 of the terminal pair or It is connected to either A2. It is also the battery located at the downstream end of the discharge battery cell group. The negative terminal of cell BT09 is the other terminal of the terminal pair, either A1 or A2, i.e., the positive terminal. It connects to the terminal that is not connected to the child.

[0380] It is preferable to use an OS transistor for transistor BT10. Because the off-current is small, the amount of charge leaking from battery cells that do not belong to the discharge battery cell group is small. This reduces the amount of power required, thus suppressing the decrease in capacity over time. Furthermore, OS transistors... Dielectric breakdown is less likely to occur when high voltage is applied. Therefore, the output voltage of the discharge battery cell group is large. Even if you hear it, the transistor BT10, which is in a non-conductive state, is connected to the battery cell BT09 and terminals. It is possible to isolate it from BT01.

[0381] Furthermore, in Figure 26, the switching circuit BT05 consists of multiple transistors BT13 and a current control It has a switch BT14, a bus BT15, and a bus BT16. Buses BT15 and B T16 is positioned between multiple transistors BT13 and the current control switch BT14. The source or drain of each of the multiple transistors BT13 is alternated every other one. They are connected to buses BT15 and BT16. Also, multiple transistors BT13 The source or drain of the other is connected between two adjacent battery cells BT09, respectively. It is being done.

[0382] Of the multiple transistors BT13, the transistor BT13 located at the very top The other end of the source or drain is the positive terminal of battery cell BT09, which is located at the uppermost part of battery section BT08. It is connected to the polarity terminal. Also, it is located at the downstream end of the multiple transistors BT13. The source or drain of transistor BT13 is located at the furthest downstream end of the battery section BT08. It is connected to the negative terminal of the BT09 battery cell.

[0383] Transistor BT13 uses an OS transistor, similar to transistor BT10. It is preferable that the OS transistor has a small off-current and therefore does not belong to the rechargeable battery cell group. This reduces the amount of charge leaking from the battery cell and suppresses the decrease in capacity over time. Yes, it is possible. Furthermore, OS transistors are less prone to dielectric breakdown when high voltage is applied. Therefore... Even if the voltage for charging the battery cells is high, transistor B will remain in a non-conductive state. T13 can be used to insulate the battery cell BT09 to which it is connected from the terminal pair BT02. .

[0384] The current control switch BT14 has a switch pair BT17 and a switch pair BT18. One end of the switch to BT17 is connected to terminal B1. Also, the switch to BT17 The other end is branched by two switches; one switch is connected to bus BT15, and the other... The switch is connected to bus BT16. One end of the switch to BT18 is connected to terminal B2. They are connected. Also, the other end of the switch to BT18 is branched by two switches, One switch is connected to bus BT15, and the other switch is connected to bus BT16. ru.

[0385] The switches in switch pair BT17 and switch pair BT18 are transistor BT1 Similar to transistor 0 and transistor BT13, it is preferable to use an OS transistor.

[0386] The switching circuit BT05 controls the transistor BT13 and the current control according to the control signal S2. By controlling the on / off state combination of the BT14 switch, the rechargeable battery cells Connect the group to the terminal pair BT02.

[0387] The switching circuit BT05, as an example, connects the rechargeable battery cell group and terminal pair BT as follows. Connect to 02.

[0388] The switching circuit BT05 provides control signals S2 to the gates of multiple transistors BT13. Accordingly, connect to the positive terminal of battery cell BT09, which is the most upstream battery cell in the rechargeable battery cell group. The transistor BT13 is made conductive. Also, the switching circuit BT05 is multiple In accordance with the control signal S2 applied to the gates of the transistors BT13, among the group of rechargeable battery cells Transistor BT1 is connected to the negative terminal of battery cell BT09, which is located furthest downstream. Connect 3 to a conductive state.

[0389] The polarity of the voltage applied to terminal pair BT02 is the same as that of the discharge battery cell connected to terminal pair BT01. This can vary depending on the group and the configuration of the BT07 transformer circuit. Also, the charging of the battery cell group To allow current to flow in one direction, terminals of the same polarity must be connected between the BT02 terminal pair and the group of rechargeable battery cells. They need to be connected. Therefore, the current control switch BT14 is controlled by the control signal S2. Depending on the polarity of the voltage applied to terminal pair BT02, switch pair BT17 and switch pair B The T18 is controlled to switch between different connection destinations.

[0390] As an example, a voltage is applied to terminal pair BT02 such that terminal B1 is positive and terminal B2 is negative. Let's explain by listing the conditions under which it is applied. At this time, the battery cell BT0, which is the downstream of the battery unit BT08 If 9 is a group of rechargeable battery cells, the switch to BT17 will, by the control signal S2, control the battery It is controlled to connect to the positive terminal of cell BT09, i.e., switch to BT17. The switch connected to bus BT16 is turned ON, and the switch is connected to bus BT17. The switch connected to 15 is turned off. Meanwhile, the switch to BT18 receives the control signal S. According to 2, it is controlled to connect to the negative terminal of the battery cell BT09. That is, The switch connected to the BT15 bus of the switch to BT18 is turned ON, and the switch to The switch connected to the BT16 bus of BT18 is turned off. In this way, the terminal Between the BT02 and the rechargeable battery cell group, terminals with the same polarity are connected. The direction of the current flowing from the terminal pair BT02 is controlled to charge the battery cells. To be controlled.

[0391] Furthermore, the current control switch BT14 is not the switching circuit BT05, but the switching circuit B It may be included in T04. In this case, the current control switch BT14 and the control signal S1 are in response to each other. By controlling the polarity of the voltage applied to terminal pair BT01, the voltage applied to terminal pair BT02 is controlled. It controls the polarity of the applied voltage. The current control switch BT14 controls the terminals of BT0 The direction of the current flowing from the battery cell group is controlled from point 2.

[0392] Figure 27 shows the configurations of switching circuits BT04 and BT05, which differ from those in Figure 26. This is a circuit diagram illustrating an example.

[0393] In Figure 27, the switching circuit BT04 consists of multiple transistor pairs BT21 and bus BT2 It has 4 and bus BT25. Bus BT24 is connected to terminal A1. BT25 is connected to terminal A2. One end of the multiple transistor pair BT21 is connected to... The signal branches off from transistors BT22 and BT23. Either the source or drain of the BT22 is connected to the BT24 bus. Either the source or drain of the converter BT23 is connected to the bus BT25. The other end of each pair of transistors BT21 is connected to two adjacent battery cells BT09. It is connected in between. Of the multiple transistor pairs BT21, the one located at the uppermost position The other end of the transistor pair BT21 is connected to the battery cell BT09, which is located at the uppermost part of the battery section BT08. It is connected to the positive terminal. Also, it is located at the downstream end of the multiple transistor pairs BT21. The other end of the transistor pair BT21 is connected to the battery cell BT located at the downstream end of the battery section BT08. It is connected to the negative terminal of 09.

[0394] The switching circuit BT04 controls transistor BT22 and transistor BT22 in response to the control signal S1. By switching the conduction / non-conduction state of BT23, the relationship between the transistor and BT21 is Switch the connection destination to either terminal A1 or terminal A2. For details, see the transistor. If BT22 is conducting, transistor BT23 will be non-conducting, and its connection point is Terminal A1. On the other hand, if transistor BT23 is conducting, then transistor BT2 Terminal 2 becomes non-conductive, and its connection point is terminal A2. Transistor BT22 and Transistor Which of the BT23 resistors becomes conductive is determined by the control signal S1.

[0395] To connect terminal pair BT01 to the group of discharge battery cells, two transistor pairs BT21 are used. It is used. In detail, the connection of two transistors to BT21 is based on the control signal S1. Once the destinations are determined, the group of discharge battery cells and the terminal pair BT01 are connected. The connections of the two transistor pairs BT21 are such that one is to terminal A1 and the other is to terminal A1. It is controlled by the control signal S1 so that it becomes child A2.

[0396] The switching circuit BT05 consists of multiple transistor pairs BT31 and buses BT34 and B Bus BT34 has T35. Bus BT34 is connected to terminal B1. Bus BT35 is , connected to terminal B2. One end of each pair of transistors BT31 is connected to the transistor It branches off from transistor BT32 and transistor BT33. Transistor BT32 One of the branches is connected to bus BT34. Also, transistor BT33 One of the branched ends is connected to bus BT35. Also, multiple transistors are paired with BT35. The other end of 1 is connected between two adjacent battery cells BT09. Of the number of transistor pairs BT31, the other end of the upstream transistor pair BT31 is It is connected to the positive terminal of battery cell BT09, which is located at the uppermost part of the battery section BT08. Furthermore, among the multiple pairs of transistors BT31, the pair of transistors BT31 located at the furthest downstream The other end is connected to the negative terminal of battery cell BT09, which is located at the downstream end of battery section BT08. ru.

[0397] The switching circuit BT05 switches between transistors BT32 and transistors according to the control signal S2. By switching the conduction / non-conduction state of BT33, the relationship between the transistor and BT31 is Switch the connection destination to either terminal B1 or terminal B2. For details, see the transistor. If BT32 is conducting, transistor BT33 will be non-conducting, and its connection point is Terminal B1. Conversely, if transistor BT33 is conducting, then transistor BT3 Terminal 2 becomes non-conductive, and its connection point is terminal B2. Transistor BT32 and Transistor Which of the BT33 resistors becomes conductive is determined by the control signal S2.

[0398] To connect the terminal pair BT02 to the battery cell group, two transistor pairs BT31 are used. It is used. In detail, the connection of two transistors to BT31 is based on the control signal S2. Once the destinations are determined, the rechargeable battery cells are connected to the BT02 terminal pair. The connections of the two transistor pairs BT31 are such that one is to terminal B1 and the other is to the terminal It is controlled by the control signal S2 to become child B2.

[0399] Furthermore, the connections of the two transistor pairs BT31 are applied to the terminal pair BT02. It is determined by the polarity of the applied voltage. Specifically, terminal B1 is the positive terminal and terminal B2 is the negative terminal. If such a voltage is applied to terminal pair BT02, then the upstream transistor pair BT31 This results in transistor BT32 becoming conductive and transistor BT33 becoming non-conductive. Thus, it is controlled by the control signal S2. On the other hand, the downstream transistor pair BT31 is The control is set such that transistor BT33 is in a conductive state and transistor BT32 is in a non-conductive state. It is controlled by signal S2. Also, terminal B1 is the negative terminal and terminal B2 is the positive terminal. When voltage is applied to terminal pair BT02, the upstream transistor pair BT31 is Transistor BT33 becomes conductive and transistor BT32 becomes non-conductive. It is controlled by the control signal S2. On the other hand, the downstream transistor pair BT31 is Control signal S such that transistor BT32 is in a conducting state and transistor BT33 is in a non-conducting state. Controlled by 2. In this way, between the terminal pair BT02 and the group of rechargeable battery cells, Terminals with opposite polarity are connected. Then, the direction of the current flowing from terminal to terminal BT02 is, The system is controlled to charge the battery cells.

[0400] The transformer control circuit BT06 controls the operation of the transformer circuit BT07. Transformer control circuit BT06 This refers to the number of BT09 battery cells included in the discharge battery cell group and the number of BT09 battery cells included in the recharge battery cell group. Based on the number of battery cells BT09, a transform signal S3 is generated to control the operation of the transformer circuit BT07. It generates the signal and outputs it to the transformer circuit BT07.

[0401] Note that the number of BT09 battery cells included in the discharge battery cell group is the same as the number of BT09 battery cells included in the recharge battery cell group. If the number of battery cells exceeds the number of BT09 cells, the charging power will be excessively large for the battery cell group. It is necessary to prevent pressure from being applied. Therefore, the voltage transformer control circuit BT06 controls the charging power The transformer circuit BT07 reduces the discharge voltage (Vdis) to a level that allows the battery cells to be charged. It outputs a transform signal S3 to control the voltage.

[0402] Furthermore, the number of BT09 battery cells included in the discharge battery cell group is the same as the number of BT09 battery cells included in the recharge battery cell group. If the number of BT09 battery cells is less than or equal to the number of BT09 battery cells, the amount of charge required to charge the battery cell group will be used. It is necessary to ensure sufficient voltage. Therefore, the transformer control circuit BT06 overloads the battery cell group. Transformer circuit B is configured to increase the discharge voltage (Vdis) within a range where no excess charging voltage is applied. Outputs a transformer signal S3 to control T07.

[0403] Note that the voltage value that constitutes excessive charging voltage is the BT09 battery cell used in the BT08 battery unit. The specifications can be determined in consideration of the product specifications, etc. Furthermore, the BT07 transformer circuit can be used for both step-up and step-down voltage conversion. The applied voltage is then applied to the terminal pair BT02 as the charging voltage (Vcha).

[0404] Here, an example of the operation of the transformer control circuit BT06 in this embodiment is shown in Figures 28(A) to (C) This will be explained using Figures 25(A) to (C). This section describes an example of the operation of the BT06 transformer control circuit, which corresponds to a group of electric battery cells and a group of rechargeable battery cells. This is a conceptual diagram for the purpose of [doing something]. Figures 28(A) to (C) show the battery control unit BT41. As shown above, the battery control unit BT41 has terminal pair BT01 and terminal pair BT02, switching control circuit BT03, switching circuit BT04, and switching circuit BT It consists of 05, the transformer control circuit BT06, and the transformer circuit BT07.

[0405] In the example shown in Figure 28(A), as explained in Figure 25(A), three consecutive high-voltage Voltage cells a through c and one low-voltage cell d are connected in series. In this case, see Figure 25( As explained using A), the switching control circuit BT03 discharges high-voltage cells a to c. The battery cell group is determined, and the low-voltage cell d is determined to be the rechargeable battery cell group. Then, the voltage is transformed. The control circuit BT06 is based on the number of battery cells BT09 included in the discharge battery cell group. Based on the ratio of the number of BT09 battery cells included in the rechargeable battery cell group, the discharge voltage (Vd Calculate the conversion ratio N from is to charging voltage (Vcha).

[0406] Note that the number of BT09 battery cells included in the discharge battery cell group is the same as the number of BT09 battery cells included in the recharge battery cell group. If the number of battery cells exceeds the number of BT09 cells, the discharge voltage is not transformed and is applied to the terminal pair BT02. When applied as is, the battery cell BT09 included in the rechargeable battery cell group is transmitted via terminal pair BT02. This could result in an excessive voltage being applied. Therefore, in cases like the one shown in Figure 28(A) Next, we will reduce the charging voltage (Vcha) applied to the terminal pair BT02 to a level lower than the discharge voltage. It is necessary. Furthermore, in order to charge the battery cell group, the charging voltage is the battery cell group The total voltage of the BT09 battery cells included must be greater than that of the transformer control circuit. BT06 is based on the number of BT09 battery cells included in the discharge battery cell group, and the charge The conversion ratio N is set to be greater than the ratio of the number of BT09 battery cells included in the battery cell group.

[0407] The voltage transformer control circuit BT06 is based on the number of battery cells BT09 included in the discharge battery cell group. When this is done, the conversion ratio N is applied to the ratio of the number of BT09 battery cells included in the group of rechargeable battery cells. It is preferable to increase it by about 1 to 10%. At this time, the charging voltage is different from the voltage of the battery cell group. Although the voltage will also increase, in reality the charging voltage will be equal to the voltage of the battery cell group. However, The voltage control circuit BT06 adjusts the voltage of the battery cell group to be equal to the charging voltage according to the conversion ratio N. This will supply current to charge the battery cells. This current is supplied by the BT06 transformer control circuit. The value set will be used.

[0408] In the example shown in Figure 28(A), the number of battery cells BT09 included in the discharge battery cell group is With 3 units, and since there is 1 BT09 battery cell in the rechargeable battery cell group, the voltage transformation control cycle For circuit BT06, the conversion ratio N is calculated to be slightly larger than 1 / 3. Then, the voltage transformation control cycle The circuit BT06 converts the discharge voltage into a charging voltage by stepping down the discharge voltage according to the conversion ratio N, and the resulting transform signal S The signal 3 is output to the transformer circuit BT07. Then, the transformer circuit BT07 responds to the transformer signal S3. The transformed charging voltage is applied to terminal pair BT02. The BT09 battery cell included in the rechargeable battery cell group is charged by the charging voltage.

[0409] Furthermore, in the examples shown in Figures 28(B) and 28(C), the conversion ratio is the same as in Figure 28(A). N is calculated. In the examples shown in Figures 28(B) and 28(C), the discharge battery cell group is The number of BT09 battery cells is less than or equal to the number of BT09 battery cells included in the rechargeable battery cell group. Therefore, the conversion ratio N will be 1 or greater. Thus, in this case, the voltage transformer control circuit BT06 is A transform signal S3 is output, which increases the discharge voltage and converts it into a charging voltage.

[0410] The transformer circuit BT07 applies a discharge voltage to the terminal pair BT01 based on the transformer signal S3. It converts the voltage to a charging voltage. Then, the transformer circuit BT07 converts the charged voltage to the terminals BT Apply to 02. Here, the transformer circuit BT07 is between terminal pair BT01 and terminal pair BT02. It is electrically isolated. As a result, the transformer circuit BT07 is the most in the group of discharge battery cells. The absolute voltage of the negative terminal of battery cell BT09 located downstream, and the lowest voltage among the group of rechargeable battery cells. This prevents short circuits caused by the difference in absolute voltage between the negative terminal of battery cell BT09 located in the current. Furthermore, as described above, the transformer circuit BT07 transforms the group of discharge battery cells based on the transformer signal S3. The discharge voltage, which is the total voltage, is converted to the charge voltage.

[0411] Furthermore, the BT07 transformer circuit is, for example, an isolated DC (Direct Current)-D transformer. A C converter or the like can be used. In this case, the transformer control circuit BT06 is an isolated DC converter. -The signal that controls the on / off ratio (duty cycle) of the DC converter is the transform signal S3. By outputting this signal, the charging voltage converted by the BT07 transformer circuit is controlled.

[0412] Isolated DC-DC converters include flyback, forward, and RCC types. (Ringing Choke Converter) method, push-pull method, half Bridge and full-bridge designs exist, but they depend on the desired output voltage level. The appropriate method will then be selected.

[0413] Figure 29 shows the configuration of the BT07 transformer circuit using an isolated DC-DC converter. The DC-DC converter BT51 has a switch section BT52 and a transformer section BT53. The BT52 switch unit switches the operation of the isolated DC-DC converter on and off. It is a switch, for example, a MOSFET (Metal-Oxide-Semiconductor) Field-effect transistors and bipolar transistors This is achieved using a switch, etc. Furthermore, the switch unit BT52 is connected to the transformer control circuit BT06. Based on the transform signal S3 that controls the on / off ratio, an isolated DC-DC converter is used. The ON and OFF states of BT51 are periodically switched. Note that the switch unit BT52 is... Various configurations are possible depending on the type of isolated DC-DC converter used. Part BT53 converts the discharge voltage applied from terminal pair BT01 into a charging voltage. The transformer section BT53 operates in conjunction with the on / off state of the switch section BT52, and The discharge voltage is converted to a charging voltage according to the on / off ratio. This charging voltage is used in the switch section BT. In a 52-period switching cycle, the longer the time spent in the ON state, the larger the value. The voltage is such that the ON state time is short during the switching cycle of the switch unit BT52. It becomes smaller. Note that when using an isolated DC-DC converter, the transformer section BT53 Within the structure, terminal pair BT01 and terminal pair BT02 can be isolated from each other.

[0414] The processing flow of the energy storage device BT00 in this embodiment will be explained using Figure 30. Figure 3 0 is a flowchart showing the processing flow of the energy storage device BT00.

[0415] First, the energy storage device BT00 acquires the voltage measured for each of the multiple battery cells BT09. Step S101). Then, the energy storage device BT00 equalizes the voltage of multiple battery cells BT09. It is determined whether the start condition for the operation is met (step S102). This start condition is, For example, the difference between the maximum and minimum voltage measured for each of the multiple battery cells BT09 is predetermined This can be determined by whether or not it is above a threshold, etc. If this starting condition is not met, (step S 102:NO), Since the voltage of each battery cell BT09 is balanced, storage The electrical device BT00 will not perform the subsequent processing. On the other hand, if the start condition is met (step S102:YES), the energy storage device BT00 performs a process to equalize the voltage of each battery cell BT09. The process is carried out. In this process, the energy storage device BT00 performs the following based on the measured voltage of each cell: It is determined whether each battery cell BT09 is a high-voltage cell or a low-voltage cell (step S103). Based on the determination result, the energy storage device BT00 determines the discharge battery cell group and the recharge battery cell group. Determine (step S104). Furthermore, the energy storage device BT00 determines the group of discharged battery cells. Control signal S1 sets the terminal pair BT01 as the connection destination, and the determined group of rechargeable battery cells is connected to the terminal A control signal S2 is generated to be set as the connection destination for the child BT02 (step S105). The BT00 unit receives the generated control signals S1 and S2 from the switching circuit BT04 and The output is sent to the switching circuit BT05. Then, the switching circuit BT04 sends the terminals The terminals BT01 and the group of discharge battery cells are connected, and the switching circuit BT05 switches the terminals BT0 2 is connected to the group of discharge battery cells (step S106). Also, the energy storage device BT00 is The number of BT09 battery cells included in the discharge battery cell group and the number of BT09 battery cells included in the recharge battery cell group Based on the number of BT09 units, a transform signal S3 is generated (step S107). Based on the voltage transformation signal S3, the energy storage device BT00 applies a discharge voltage to the terminal pair BT01. This is converted to a charging voltage and applied to the terminal pair BT02 (step S108). Charge is transferred from the group of battery cells to the group of rechargeable battery cells.

[0416] Also, although the flowchart in Figure 30 shows multiple steps in order, each step The execution order of the steps is not limited to the order in which they are listed.

[0417] As described above, according to this embodiment, when transferring charge from a group of discharge battery cells to a group of rechargeable battery cells Unlike the capacitor system, which temporarily stores charge from a group of discharge battery cells, the rechargeable battery cells... It does not require a configuration that releases to the group. This eliminates the charge transfer efficiency per unit time. The efficiency can be improved. Also, the switching circuits BT04 and BT05 Therefore, among the discharge battery cell group and the rechargeable battery cell group, the battery cells connected to the transformer circuit are, respectively They can be switched individually.

[0418] Furthermore, the transformer circuit BT07 controls the number of battery cells BT09 included in the discharge battery cell group. Based on the number of battery cells BT09 included in the rechargeable battery cell group, markings are made on the terminal pair BT01. The applied discharge voltage is converted into a charging voltage and applied to the terminal pair BT02. Regardless of how the BT09 battery cells on the charging and discharging sides are selected, charge transfer is performed without any problems. It can be expressed.

[0419] Furthermore, OS transistors are used for transistors BT10 and BT13. As a result, leakage occurs from battery cell BT09, which does not belong to the rechargeable battery cell group or the dischargeable battery cell group. This reduces the amount of charge that does not contribute to charging and discharging. The decrease in capacitance 9 can be suppressed. Also, OS transistors are Si transistors Compared to that, the variation in thermal properties is smaller. As a result, the temperature of the battery cell BT09 rises. However, normal operation such as switching between conductive and non-conductive states according to control signals S1 and S2 It can be made to work. [Examples]

[0420] In this example, particles having a lithium manganese composite oxide according to one aspect of the present invention were produced. The characteristics were then evaluated. The manufacturing procedure will be explained based on the flowchart in Figure 1.

[0421] <Synthesis> First, particles containing lithium manganese composite oxide were fabricated.

[0422] (Step S11) First, we use Li2CO3, MnCO3, and NiO as starting materials. The ratio (molar ratio) is Li2CO3:MnCO3:NiO = 0.84:0.8062:0 The weight was measured to be 0.318.

[0423] (Step S12) Next, ethanol was added to the starting material and then mixed using a bead mill. The mixing process was as follows: By rotating the processing chamber of the bead mill at a peripheral speed of 10 m / s and performing the mixing for 30 minutes, A mixture of raw materials was obtained.

[0424] (Step S13) Next, the mixed raw materials were subjected to heat treatment. The heat treatment was carried out in an air atmosphere at a heating temperature of 7 By performing the process at 5°C, the ethanol contained in the mixed raw materials is evaporated, and the mixed raw material I received payment.

[0425] (Step S14) Next, the mixed raw materials were placed in the crucible and fired. The firing process involved drying at a flow rate of 10 L / min. By firing in an air atmosphere at a temperature of 1000°C for a firing time of 10 hours, A lithium manganese composite oxide was synthesized.

[0426] (Step S15) Next, a crushing process is performed to dissolve the sintered lithium manganese composite oxide in which the primary particles have been sintered. The process was carried out. The crushing treatment involved adding ethanol to the sintered lithium manganese composite oxide, and then... The processing chamber of the lithium mill is rotated at a peripheral speed of 12 m / s and processed for 4 hours to produce a powdered lithium manifold. A cancerous composite oxide was obtained.

[0427] (Step S16) Next, the lithium manganese composite oxide after the crushing process was subjected to heat treatment. By heating at a temperature of 75°C in an air atmosphere, the contents of the mixed raw materials are extracted. The ethanol was evaporated. Next, the resulting lithium manganese composite oxide was placed in a crucible and baked. Firing was carried out. The firing conditions were 800 °C for 3 hours in a dry air atmosphere of 10 L / min. After firing, the obtained powder was designated as Sample A. Sample A has a composition formula of Li 1.68 Mn0 .8062 Ni 0.318 O3, although it may deviate from this composition.

[0428] <Coating layer> Next, a carbon-containing layer was formed on the obtained Sample A. First, 1 g of water was added to 0.1 g of graphene oxide and kneaded using a kneader to prepare a dispersion solution of graphene oxide. The rotation speed of kneading was 2000 rpm, and the kneading time was 5 minutes per cycle, repeated 4 times. In the first kneading, the amount of water was 3 / 10 of the total amount, in the second kneading, an additional 3 / 10 was added, in the third kneading, an additional 3 / 10 was added, and in the fourth kneading, an additional 1 / 10 was added for kneading.

[0429] (Step S17) Next, 5 g of Sample A was added to the prepared dispersion solution, and 1.1 g of water was further added, followed by performing solid kneading 4 times. The solid kneading was carried out using a kneader with a rotation speed of 2000 rpm and a kneading time of 5 minutes per cycle. The obtained mixture was dried under reduced pressure at 50 °C using a Berger, then crushed in an alumina mortar to obtain Sample B, which is a lithium manganese composite oxide coated with graphene oxide.

[0430] (Step S18) Next, the graphene oxide coated on the surface of the lithium manganese composite oxide was reduced. Ascorbic acid was used as the reducing (Step S18) agent, and a mixed solution of ethanol and water was used as the solvent. In the mixed solution, the concentration of ethanol was 80% by volume. The lithium The ummanganese complex oxide was mixed with 16.87 wt% ascorbic acid and lysyl hydroxide. A reducing solution was prepared by adding 3.9 wt% of lithium. The resulting powder was placed in the reducing solution and heated at 60°C. It was processed for 3 hours and then reduced.

[0431] (Step S19) Next, the obtained solution was filtered by suction filtration. For filtration, a filtration system with a particle retention capacity of 1 μm was used. Filter paper was used. Afterwards, it was washed and filtered again.

[0432] Next, the powder obtained by filtration was ground in a mortar. Then, it was fermented at 170°C under reduced pressure for 10 minutes. After some time, it was allowed to dry.

[0433] Through the above process, a lithium manganese composite oxide powder with graphene formed on its surface is obtained. Sample (C) was prepared.

[0434] <Electrode fabrication> Next, electrodes were fabricated using the obtained sample C. Sample C was used as the active material, and a conductive additive was used. Acetylene black (AB) was used as the binder, and PVdF was used as the binder.

[0435] First, PVdF and AB are combined with the polar solvent NMP (N-methyl-2-pyrrolidone) The mixture was kneaded. The kneading speed was 2000 rpm, and the kneading time was 5 minutes. Furthermore, the active ingredients Sample C was added as a component and kneaded. The kneading speed was 2000 rpm, and the kneading time was 1 The process was repeated 5 times, with each cycle lasting 5 minutes. NMP was then added and the mixture was kneaded. The kneading rotation speed was... The mixing was performed at 2000 rpm, with each mixing session lasting 10 minutes, and this was repeated twice. A slurry-like electrode mixture composition was obtained. The composition of the electrode mixture was in the weight ratio of sample C:A. B:PVdF = 90:5:5

[0436] Next, the electrode mixture composition was applied onto the aluminum foil, which served as the current collector. The surface of the aluminum foil was pre-coated with an undercoat. Then, it was dried in a ventilated drying oven at 80°C. Then, I let it dry for 30 minutes.

[0437] Next, the electrodes were pressed using a roll press machine. The film thickness after electrode coating was compared to the film thickness. The press pressure was adjusted to reduce the thickness by 20%. The press temperature was set to 120°C. did.

[0438] Further heat treatment was then performed. The heat treatment conditions were a reduced pressure atmosphere (1 kPa) and 270°C. A 10-hour treatment was performed. Through the above steps, one aspect of the present invention, "Lithium An electrode X having "particles containing manganese composite oxide" was obtained.

[0439] <Half-cell characteristics> Next, a half-cell was fabricated using the obtained electrode X. A coin cell was used for the cell. Furthermore, lithium was used as the counter electrode of the half-cell. The electrolyte was LiP Using F6, a mixture of aprotic organic solvents EC and DEC was prepared in a 1:1 volume ratio. A composite solution was used. Polypropylene (PP) was used as the separator.

[0440] Next, the fabricated half-cells were aged at 25°C. Specifically, For the first charge / discharge cycle, a constant voltage of 150mAh / g was applied at 0.1C (current density 30mA / g). After the initial current charge, a constant current discharge was performed at 0.1C with a lower limit of 2V, followed by a second discharge at 0.1C. After constant current charging at 80mAh / g, constant current discharge at 0.1C with a lower limit of 2V was performed three times. As an example, constant current charging was performed at 0.1C at 210mAh / g, and then at 0.1C with a lower limit of 2V. After discharging with current, and then performing a constant current charge of 240mAh / g at 0.1C for the fourth time, 0 Constant current discharge was performed at 0.1C with a lower limit of 2V, and for the fifth time, a constant current of 270mAh / g was measured at 0.1C. After charging with current, constant current discharge was performed at 0.1C with a lower limit of 2V.

[0441] After the above aging process, the charge and discharge characteristics were measured at 25°C. Charging was 0 The procedure was performed with a constant current of 0.1C and an upper voltage limit of 4.8V, and the discharge was performed with a constant current of 0.1C and a lower voltage limit of 2V. The obtained charge-discharge curve is shown in Figure 31. One embodiment of the present invention, lithium manganese composite acid By using particles containing ionized compounds, a high discharge capacity exceeding 300 mAh / g can be obtained. And it was done. [Examples]

[0442] In this embodiment, "particles having lithium manganese composite oxide," which is one aspect of the present invention, Scanning transmission electron microscopy (STEM) (Lectron Microscopy), Energy Dispersive X-ray Spectroscopy (EDX:En (Dispersive X-ray spectroscopy) and microscopic The results were evaluated using electron diffraction.

[0443] First, we prepared sample H-1 and electrode H-3 for observation.

[0444] For sample H-1, steps S11 to S17 shown in Figure 1 were performed. Refer to Example 1 for the conditions of the top.

[0445] Furthermore, for electrode H-3, after performing steps S11 to S19 as shown in Figure 1... Then, electrode H-3 was prepared using the obtained sample (the sample obtained here will be called sample H-2). For the electrode fabrication conditions, refer to electrode X shown in Example 1.

[0446] For sample H-1 and electrode H-3, FIB (Focused Ion Beam) After thinning the section using a focused ion beam processing and observation system, scanning light Over-electron microscopy (STEM: Scanning Transmission Electron Microscopy) Observations were performed using TEM (Telescopic Microscopy). Figure 32 shows the TEM observation image. Figure 32(A) shows the observation results for sample H-1, and (B) shows the observation results for electrode H-3. In this also represents one aspect of the present invention: a cross-section of a particle 141 having a lithium manganese composite oxide. This was observed.

[0447] Next, EDX evaluation was performed on the locations marked with numbers 1 to 5 in Figures 32(A) and (B). The evaluation results for sample H-1 are shown in Table 1, and the evaluation results for electrode H-3 are shown in Table 2. These are shown separately. Tables 1 and 2 also show the distance from the particle surface to each measurement point. Figures 47 to 51 show the spectra at each measurement point. For sample H-1, see Figure 47(A (A) is measurement point 1, (B) is measurement point 2, Figure 48 (A) is measurement point 3, (B) is measurement point 4, Figure 49 (A) shows the spectrum at measurement point 5. For electrode H-3, Figure 49(B) shows the spectrum at measurement point 1. Figure 50(A) shows measurement point 2, (B) shows measurement point 3, Figure 51(A) shows measurement point 4, (B) shows measurement point The spectrum of 5 is shown.

[0448] [Table 1]

[0449] [Table 2]

[0450] Here, in Tables 1 and 2, the sum of the atomic ratios of manganese, nickel, and oxygen is The values ​​were standardized to be approximately 100%.

[0451] Next, the atomic ratios of manganese, nickel, and oxygen obtained from EDX are b and c, respectively. Let , and d be the values, and for each evaluation score, the value of d÷(b+c)(=A) was calculated. Horizontal axis The distance from the particle surface is plotted on the vertical axis, and the value of A is plotted on the vertical axis. For sample H-1 and electrode H-3, a program is developed. The resulting graph is shown in Figure 33.

[0452] First, let's explain the region less than 10 nm from the surface. In sample H-1, the region is 1.2 nm from the surface. At the measurement point of nm, the value of A is 1.6, and at electrode H-3, at the measurement point of 2.2 nm from the surface, the value of A is It was 1.9.

[0453] Next, we will explain the region above 20 nm from the surface. In sample H-1, this region extends from 26 nm from the surface. At measurement point m, the value of A is 2.4, and at measurement points where the distance from the surface is greater than that, The value of A was also greater than 2.4. Furthermore, at electrode H-3, A was measured at a measurement point 22 nm from the surface. The value of is 2.9, and even at measurement points at a greater distance from the surface, the value of A is 2. It was greater than 9.

[0454] From the above, the ratio A of the number of oxygen atoms to the sum of the number of manganese and nickel atoms is, It can be seen that the value differs between the immediate vicinity and the region closer to the interior of the particle. In one embodiment of the invention, particles having lithium manganese composite oxide have different values ​​of A, Both regions have two areas, and in the region closer to the surface, the value of A is smaller. There are cases where this is the case.

[0455] Furthermore, the A value of a region near the surface, for example, a region less than 10 nm from the surface, is... The A value in the region closer to the interior of the particle, for example, the region 20 nm or more from the surface, is greater than small.

[0456] Next, high-angle scattering annular dark-field scanning transmission electron microscopy (HAADF-STEM) of electrode H-3. :High-Angle Annular Dark Field Scanning Observation of images (Transmission Electron Microscopy) The results are shown in Figure 34. Figure 34(A) shows the region 142 enclosed by a solid line in Figure 32(B), and Figure 34 (B) shows the observation results for each of the regions 143 enclosed by solid lines in Figure 32(B). For observing HAADF-STEM images, spherical aberration correction is required. TEM images were observed using the TEM Corrector function. The combined bright-field image and diffraction pattern analysis image obtained by TEM is called a high-resolution TEM image. High-resolution TEM images obtained using surface aberration correction are specifically called Cs-corrected high-resolution TEM images. To acquire s-corrected high-resolution TEM images, an atomic-resolution analytical electron microscope (JE) manufactured by JEOL Ltd. is used. The M-ARM200F was used. The acceleration voltage was set to 200kV. Here, Figure 34(A) shows the particles. On the side further from the surface of the child, there are layers V1 and V2 where bright spots are formed, and layer V1 and It shows layer T1, which is located between layers V1 and V2 and forms dimmer bright spots compared to layers V1 and V2. The distance between layer V1 and T1 is approximately equal to the distance between layer T1 and V2. Here, for example, manga Compared to nickel and other metals, lithium has a smaller atomic number, and HAADF-STEM observations show that In this case, the brightness becomes dimmer. Therefore, for example, layer T1 is in a layered salt rock structure. Furthermore, it is possible that this is a layer within the (0 0 1) plane that is mainly formed of lithium.

[0457] Next, layers U1 to are located in a region closer to the particle surface than layers V1, V2, and T1. Layer U3 is shown. Here, layers U1 to U3 all form bright spots of roughly the same brightness. This is a layer. Here, the distance between layers U1 and U3 is approximately equal to the distance between layers V1 and V2. Also, In layer U2, which is sandwiched between layers U1 and U3, the brightness of the bright spots is brighter compared to layer T1. Therefore, for example, compared to layer T1, layer U2 has a higher abundance of manganese and nickel. There is a possibility.

[0458] Next, at measurement point 1 (*1) and measurement point 2 (*2) in the TEM photograph shown in Figure 39, the pole Microelectron diffraction was evaluated. Measurement point 2, shown in Figure 39, is closer to the surface of the particle, and the particle surface This is the region within 10 nm. Measurement point 1 is closer to the interior of the particle compared to measurement point 2. This is the region. The results of micro-electron diffraction at each measurement point are shown in Figure 35. Figure 35(A) is shown in Figure 39. Figure 35(B) shows the results of micro-electron diffraction at measurement point 1, and Figure 35(B) shows the results at measurement point 2.

[0459] Furthermore, the measured values ​​of the positional relationship (distance, angle) of the spots in the obtained diffraction pattern are from JCP. The crystal structure of Li2MnO3 described on DS card No. 84-1634 is a good match. A response was observed. More specifically, the diffraction pattern at measurement point 1 (Figure 35(A)) was as described above. In the crystal structure, the diffraction pattern with the incident direction [-1 -1 0] and measurement point 2 (Figure 35) The diffraction pattern of B)) is similar to the diffraction pattern with the incident direction [3 2 -3], and each is good. Correspondence was observed. On the right side of each diagram is the corresponding JCPDS card No. 84-1634. The corresponding distance and angle are shown. Additionally, the measured values ​​are shown on the left side of each diagram.

[0460] Furthermore, electron diffraction observations were performed on particles different from those shown in Figure 39. Specifically, see Figure 40. At measurement point 1 (*1) and measurement point 2 (*2) in the TEM image shown, ultra-low electron diffraction was measured. The evaluation was performed. Measurement point 2, shown in Figure 40, is closer to the surface of the particle, and is within 10 nm of the particle surface. This is an internal region. Measurement point 1 is a region closer to the interior of the particle compared to measurement point 2. Figure 41 shows the results of micro-electron diffraction at each measurement point. Figure 41(A) shows the results for measurement point 1 shown in Figure 40. Figure 41(B) shows the results of micro-electron diffraction at measurement point 2.

[0461] Furthermore, the measured values ​​of the positional relationship (distance, angle) of the spots in the obtained diffraction pattern are from JCP. The crystal structure of Li2MnO3 described on DS card No. 84-1634 is a good match. A response was observed. More specifically, the diffraction pattern at measurement point 1 (Figure 41(A)) was as described above. In the crystal structure, the diffraction pattern with the incident direction

[0100] and measurement point 2 (Figure 41(B)) The diffraction patterns of ) correspond well with the diffraction patterns of the incident direction [3 2 -3]. This was observed. On the right side of each figure is the corresponding JCPDS card No. 84-1634. The distance and angle are shown. The measured values ​​are also shown on the left side of each diagram.

[0462] Here, as described in Embodiment 1, the first region and the second region are layered rock salt. It is preferable that the structure has a molded form and that the <1 1 0> orientation of the first region and the <3 2 -3> orientation of the second region are parallel. For example, the arrangement of layers containing lithium and manganese, or layers of oxygen, in a plane is roughly maintained. Because they can be joined together, it can be said that the two domains have good consistency. [Examples]

[0463] In this embodiment, the relationship between the surface area and properties of particles according to one aspect of the present invention is described.

[0464] For step S15 shown in Example 1, the crushing conditions were varied, and the surface of the resulting particles was... We evaluated the relationship with the product.

[0465] Particles according to one embodiment of the present invention were prepared according to steps S11 to S19 in Figure 1. Here, for the crushing process shown in step S15, the crushing conditions shown in Table 2 are used, and the sample Samples Z-1 to Z-6 were prepared. Furthermore, for samples Z-4 to Z-6, the coating layer was prepared. The formation was not performed.

[0466] [Table 3]

[0467] The specific surface area of ​​the obtained samples Z-1 to Z-6 was evaluated. The results are shown in Table 3.

[0468] Next, electrodes were fabricated using the obtained samples Z-1 to Z-6. The electrode fabrication conditions were as follows: See Example 1.

[0469] Next, using the fabricated electrodes, the same electrolyte, separator, and counter electrode conditions as shown in Example 1 were used. Using this method, half-cells were fabricated using coin cells.

[0470] Next, the fabricated half-cells were charged and discharged. The charging conditions were a constant current of 30 mA / g for 4 The upper limit was set at 0.8V, and the discharge conditions were a constant current of approximately 30mA / g with a lower limit of 2.0V. The obtained discharge capacities are shown in Table 3.

[0471] As peripheral speed increased, there was a tendency for the specific surface area to increase. Also, the shape of the coating layer Under the conditions observed, the larger the specific surface area, the higher the capacity, and in sample Z-2, the specific surface area was 1 4.0m 2 The obtained discharge capacity was 274 mAh / g, and the specific surface area of ​​sample Z-3 was 14 0.8m 2 The obtained discharge capacity was 291 mAh / g, both of which are very high values. .

[0472] On the other hand, in samples without a coating layer, the specific surface area increases as the peripheral speed increases. However, in sample Z-5, the specific surface area is 14.6 m². 2 Discharge capacity is 91mAh / g In sample Z-6, the result was 30.3 m 2 With a discharge capacity of 101mAh / g compared to / g, the beads For example, a damage layer may be formed on the particle surface due to the crushing process by the rubbing, or the particle surface Possible causes include partial wear of the surface layer. By forming a coating layer, the surface area can be improved. We were able to increase the capacity and achieve a higher level of performance. [Examples]

[0473] In this example, "particles having lithium manganese composite oxide" according to one aspect of the present invention are used. A thin storage battery, as shown in Embodiment 2, was fabricated.

[0474] <Fabrication of the positive electrode> First, "particles having a lithium manganese composite oxide" according to one aspect of the present invention were prepared.

[0475] First, steps S11 to S14 shown in Example 1 were performed.

[0476] (Step S15) Next, a crushing process was performed. The processing conditions for the bead mill were lithium manganese composite oxide 24 The procedure was performed at a peripheral speed of 8 m / s per 0 g for 12 hours. Ethanol was used as the solvent.

[0477] (Step S16) Next, the lithium manganese composite oxide after the crushing process was heat-treated and dried. The resulting powder is designated as sample A2. Then, the obtained lithium manganese composite oxide is subjected to a crucible. It was placed in a container and fired. The firing conditions were under a dry air atmosphere of 10 L / min. I set it to 0°C for 3 hours.

[0478] (Step S17) Next, a layer containing carbon was formed on the obtained sample A2. First, 4g of graphene oxide was added. Then, 50 ml of water was added and the mixture was kneaded using a kneader to prepare a dispersion solution of graphene oxide. Next, 200g of sample A2 was added to the prepared dispersion solution, and then 90ml of water was added. Then, the mixture was kneaded twice. For the kneading, a mixing machine was used, with a rotation speed of 80 rpm and a kneading time of The process was repeated twice, with each cycle lasting 30 minutes. The resulting mixture was dried in a forced-air drying oven at 50°C. After drying, it is crushed in an alumina mortar and pestle, and lithium manganese compound coated with graphene oxide. Sample B2, a composite oxide, was obtained.

[0479] (Step S18) Next, the graphene oxide coated on the surface of the lithium manganese composite oxide was reduced. Ascorbic acid was used as the agent, and an 80% by volume aqueous ethanol solution was used as the solvent. The weight of the lithium manganese composite oxide coated with graphene oxide was ascorbic acid. A reducing solution was prepared by adding 16.87 wt% of nitrate and 3.9 wt% of lithium hydroxide. The sample B2 was placed in a reducing solution and reduced by treating it at 60°C for 3 hours.

[0480] (Step S19) Next, the solvent was separated from the obtained solution using a centrifuge, and the separated liquid was discarded. After that, The process of adding pure water for washing, centrifuging, and then discarding the separated liquid was repeated four times. The separation rotation speed was set to 9000 rpm, and each cycle lasted 3 minutes. Next, the solvent was added to the separated sample. The solution was obtained by adding pure water to adjust the concentration to 121 g / l. The liquid was heated to 150°C and then spray-dried.

[0481] Next, the powder obtained by spray drying was dried under reduced pressure for 10 hours.

[0482] Through the above process, a lithium manganese composite oxide powder with graphene formed on its surface is obtained. Sample C2 was prepared.

[0483] Next, the positive electrode of the battery was fabricated using sample C2. Sample C2 was used as the active material, and the conductive Acetylene black (AB) was used as an auxiliary agent, and PVdF was used as a binder. The composition of the active material, AB, and PVdF is active material:AB:PVdF=90:5:5(wei It was set to ght%).

[0484] A slurry was prepared by mixing the active material, AB, PVdF, and NMP using a kneader. Then, a continuous coating machine is applied to the 20 μm thick aluminum foil that has been treated with an undercoat. The slurry was applied to one side of the aluminum foil using [a specific method / tool]. Then, it was dried in a drying oven at 70°C. After drying for 0 minutes, the machine was dried again at 90°C for 10 minutes.

[0485] Subsequently, further heat treatment was performed. The heat treatment conditions were a reduced pressure atmosphere (1 kPa) and 250°C. The process was carried out at °C for 10 hours. After that, the press pressure was set to 1.5 MPa and the press temperature was changed. The temperature was set to 120°C. Through the above process, one aspect of the present invention, "Lithium Manganese Composite," was produced. A positive electrode X2 having oxide-containing particles was obtained. The amount of active material supported in the obtained positive electrode was 7.2 mg / cm 2 That was the case.

[0486] Next, using the fabricated positive electrode X2 and the negative electrode using graphite as the active material, we will proceed as shown in Embodiment 2. A thin-profile battery, battery A, was fabricated, and the positive electrode X2 was subjected to aging.

[0487] An aluminum film covered with heat-sealable resin was used as the outer casing for battery A. The electrolyte was: LiPF6 was used as the salt, and a solvent consisting of a mixture of EC, DEC, and EMC was used. They were there. Also, PP was used for the separator.

[0488] Next, the fabricated battery A is subjected to a 20 MPa press using a press machine while being charged and discharged. The discharge was performed three times. The lower limit voltage of the discharge was set to 2V.

[0489] <Fabrication of the negative electrode> Next, a negative electrode for use in a rechargeable battery was fabricated. SiO was used as the active material, and A was used as the conductive additive. Polyimide was used as the binder for component B.

[0490] First, the ratio of SiO:AB:polyimide precursor is 80:5:15 (weight%). Weighed out sea urchin SiO, AB, and polyimide precursors. As for the polyimide precursor, A 13.7 weight% solution was used, with NMP as the solvent.

[0491] First, SiO and AB were mixed in a kneader. Then, NMP was added little by little, and the planetary method The mixture was kneaded using a kneading machine to produce a paste. N was added to make the paste. The total amount of MP was adjusted so that the solid content ratio of the paste was approximately 60%. Here, "stiff paste" refers to... This refers to mixing at high viscosity. This process improves the dispersibility of the active material and the conductive additive. It is possible.

[0492] Next, a polyimide precursor solution using NMP as the solvent is added to the prepared paste and mixed. The mixture was kneaded using a mixing machine. A slurry was prepared through the above process. The solid content ratio was 40% by weight.

[0493] Next, the slurry was applied to one side of an 18 μm thick rolled copper foil using a continuous coating machine. Afterward, the solvent was evaporated by heat treatment using a drying oven. The heat treatment conditions were 50°C and 180°C. The material was heat-treated for 180 seconds, followed by another heat treatment at 75°C for 180 seconds. The material obtained through the above process was... Let the negative electrode be denoted as negative electrode Y. The amount of active material loaded onto the obtained negative electrode Y is 1.9 mg / cm³. 2 That was the case.

[0494] Next, using the fabricated negative electrode Y and the positive electrode using lithium cobalt oxide as the active material, a thin-walled device was constructed. Battery B, a storage battery, was fabricated, and the negative electrode Y underwent aging.

[0495] An aluminum film covered with heat-sealable resin was used as the outer casing for battery B. In this study, LiPF6 was used as the salt, and a solvent mixture of EC and DEC was used. Furthermore, PP was used for the separator.

[0496] Next, the fabricated battery B was charged and discharged.

[0497] <Fabrication of storage battery C> The casing of battery A was opened and the positive electrode X2 was removed. The casing of battery B was also opened. Then, the negative electrode Y was removed.

[0498] Next, a storage battery C was fabricated using the extracted positive electrode X2 and negative electrode Y.

[0499] An aluminum film covered with heat-sealable resin was used as the outer casing for battery C. This method uses LiPF6 as the electrolyte and a ratio of 3:7 for the aprotic organic solvents EC and DEC. A mixed solution was used, prepared by mixing the ingredients in the specified volume ratio. PP was used as the separator.

[0500] Next, the fabricated battery C was charged and discharged. At 25°C, the current density was 0.1C (25°C). Charging was performed at a constant current of mA / g, with an upper limit of 4.6V and a lower limit of 1.5V. The discharge curve is shown in Figure 36. Here, the horizontal axis represents the capacity per unit weight of the positive electrode active material.

[0501] Using superior materials with high capacity per unit weight for the positive electrode active material and the negative electrode active material. This allowed us to obtain a storage battery with high capacity. [Examples]

[0502] In this example, "particles having lithium manganese composite oxide" according to one aspect of the present invention are used. A thin storage battery as shown in Embodiment 2 was fabricated. In this embodiment, multiple positive electrode active materials were used. By providing layers and multiple negative electrode active material layers and stacking them, a larger capacity storage battery can be manufactured. Ta.

[0503] <Fabrication of the positive electrode> A positive electrode active material for use in a storage battery was synthesized. First, steps S11 to S11 shown in Example 1 were synthesized. We performed 14 steps.

[0504] (Step S15) Next, a crushing process was performed. The processing conditions for the bead mill were lithium manganese composite oxide 60 The parameters were 0g, circumferential speed 12m / s, and 10 hours.

[0505] (Step S16) Next, the lithium manganese composite oxide after crushing was heat-treated and dried. The sample was heated on a hot plate at 75°C, then dried at 100°C under reduced pressure. The obtained lithium manganese composite oxide was placed in a crucible and calcined. The calcination conditions were 10 The process was carried out at 800°C for 3 hours under a dry air atmosphere of L / min. After firing, the obtained... Let the powder be sample A3.

[0506] (Step S17) Next, a layer containing carbon was formed on the obtained sample A3. First, the aqueous dispersion of graphene oxide... The solution was prepared. The water was divided into three equal parts, and a kneading machine was used to mix each time it was added to the graphene oxide. A dispersion solution of graphene oxide was prepared by mixing and kneading the mixture. 10g of graphene oxide to water The solution was added in a proportion that made up 150 ml. Next, sample A2 was added to the 150 ml of the prepared dispersion solution. 500g of the mixture was added to 200mL of water, and kneaded until a solid paste was formed. Next, the resulting mixture was prepared. The mixture was dried at 70°C using a ventilated drying oven, then crushed in an alumina mortar and pestle, and graphite oxide was produced. Sample B3, a lithium manganese composite oxide coated with a special coating, was obtained.

[0507] (Step S18) Next, the graphene oxide coated on the surface of the lithium manganese composite oxide was reduced. Ascorbic acid was used as the agent, and an 80% by volume aqueous ethanol solution was used as the solvent. The weight of the lithium manganese composite oxide coated with graphene oxide was ascorbic acid. A reducing solution was prepared by adding 16.87 wt% of nitrate and 3.9 wt% of lithium hydroxide. The sample B3 was placed in a reducing solution and reduced by treating it at 60°C for 3 hours.

[0508] (Step S19) Next, the solvent was separated from the obtained solution using a centrifuge, and the separated liquid was discarded. After that, The process of adding pure water for washing, centrifuging, and then discarding the separated liquid was repeated five times. The separation rotation speed was set to 2000 rpm to 6000 rpm, and each cycle lasted 3 minutes. Next, dissolution Pure water was added to the sample from which the medium had been separated. For every 80g of sample B3 before reduction, water was added. The solution was obtained by adding it at a ratio of 1 L. Then, the obtained solution was heated to 150°C and sprayed. - Drying treatment was performed.

[0509] Next, the powder obtained by spray drying was dried at 170°C under reduced pressure for 10 hours. did.

[0510] Through the above process, a lithium manganese composite oxide powder with graphene formed on its surface is obtained. Sample C3 was prepared.

[0511] Next, the positive electrode of the battery was fabricated using sample C3. Sample C3 was used as the active material, and the conductive Acetylene black (AB) was used as an auxiliary agent, and PVdF was used as a binder. The composition of the active material, AB, and PVdF is active material:AB:PVdF=90:5:5(wei It was set to ght%).

[0512] A slurry was prepared by mixing the active material, AB, PVdF, and NMP using a kneader. Next, a continuous coating machine is used on a 20 μm thick aluminum foil that has been treated with an undercoat. A slurry was applied using [a specific method]. The positive electrode had active material layers on both sides of the aluminum foil, and one side had active material [another specific method]. A positive electrode with a material layer was prepared. Next, the solvent was evaporated using a drying oven at 70°C for 10 minutes. Afterward, the solvent was evaporated at 90°C for 10 minutes.

[0513] Next, heat treatment was performed at a reduced pressure atmosphere (1 kPa) and 250°C for 10 hours. Then, pressing was performed using a press machine. Through the above process, one aspect of the present invention, "Lithium A positive electrode X3 was obtained having "particles containing a manganese composite oxide". The dosage is 15.5 mg / cm² per side. 2 That was the case.

[0514] Next, the fabricated positive electrode X3 was charged and discharged using lithium metal as the counter electrode. Electrolyte This method used LiPF6 as the salt and polyethylene carbonate (PC) as the solvent. The discharge condition was limited to a minimum of 2V.

[0515] After that, the positive electrode X3 was removed from the electrolyte.

[0516] <Fabrication of the negative electrode> Next, a negative electrode for use in a rechargeable battery was fabricated. SiO was used as the active material, and A was used as the conductive additive. Polyimide was used as the binder for component B.

[0517] First, the ratio of SiO:AB:polyimide precursor is 80:5:15 (weight%). Weighed out sea urchin SiO, AB, and polyimide precursors. As for the polyimide precursor, A 13.7% solution using NMP as the solvent was used.

[0518] A slurry was prepared by mixing SiO, AB, a polyimide precursor, and NMP. For the preparation of the rally, refer to the process for preparing the negative electrode Y shown in Example 4.

[0519] Next, the slurry was applied to 18 μm thick rolled copper foil using a continuous coating machine. The tempered layer was applied to both sides of the copper foil. Afterward, drying was performed using a drying oven. The drying conditions were as follows: 5 The material was heat-treated at 0°C for 180 seconds, followed by heat treatment at 75°C for 180 seconds. The resulting negative electrode is designated as negative electrode Y2. The amount of active material supported on the resulting negative electrode Y is 1.8 per side. mg / cm 2 That was the case.

[0520] Next, the fabricated negative electrode Y2 was charged with lithium metal as the counter electrode. The electrolyte was LiPF6 was used as the salt, and polyethylene carbonate (PC) was used as the solvent. Afterward, the negative electrode Y2 was removed from the electrolyte.

[0521] <Battery manufacturing> Next, a thin storage battery C2, as shown in Embodiment 2, was fabricated. As the positive electrode, both One positive electrode X3 with an active material layer on one side and two positive electrodes X3 with an active material layer on one side were prepared. In addition, two negative electrodes, Y2, were prepared, each having an active material layer on both sides.

[0522] The positive electrode X3, negative electrode Y2, and separator 507 are as shown in Figure 37, positive electrode active material layer 50 2 and a positive electrode X3 having aluminum foil as a positive electrode current collector 501, and a negative electrode active material layer 5 A separator 507 is placed between 05 and the negative electrode Y2, which has copper foil as a negative electrode current collector 504. It was constructed and layered.

[0523] An aluminum film covered with heat-sealed resin was used as the outer casing for the storage battery C2. The solution uses LiPF6 as the electrolyte, and contains EC, DEC, and ethyl methyl carbonate. A mixed solution of (EMC) in a weight ratio of 3:6:1 was used. In addition, the separator was Polypropylene (PP) was used. In addition, less than 1% of VC (vinyl carbonate) was added as an additive. (Nate) and less than 1% propanesultone (PS) were added.

[0524] Next, the fabricated battery C2 was charged and discharged. At 25°C, the current density was 0.1C (1 Charging was performed at a constant current of 2mA / g, with an upper limit of 4.6V and a lower limit of 1.5V for discharging. The charge-discharge curve is shown in Figure 38(A). Here, the horizontal axis represents the capacity per unit weight of positive electrode active material. Furthermore, Figure 38(B) shows the weight of the positive electrode current collector and the negative electrode current collector, calculated from the sum of the weights of the positive and negative electrodes. The charge-discharge curve is shown with the normalized capacity on the horizontal axis, using the value obtained by subtracting the sum of the quantities.

[0525] Using superior materials with high capacity per unit weight for the positive electrode active material and the negative electrode active material. This allowed us to obtain a storage battery with high capacity. [Examples]

[0526] In this embodiment, we will describe a case in which particles according to one aspect of the present invention form secondary particles.

[0527] First, steps S11 to S16 shown in Figure 1 are performed, and lithium manganese composite oxide is obtained. Sample A4 was obtained. For steps S11 to S16, refer to Example 1. This is possible. Further details regarding the conditions are described below.

[0528] In step S11, the starting materials are selected in a weight ratio of Li2CO3:MnCO3:NiO= The weights were measured so that the ratio was 0.84:0.8062:0.318.

[0529] In step S12, the processing conditions for the bead mill are a peripheral speed of 10 m / s and a time of 30 minutes. Ta.

[0530] In step S13, drying is performed under an atmospheric atmosphere at 75°C, followed by drying under reduced pressure at 100°C. The drying process took 1 hour.

[0531] In step S14, the firing conditions are 10 L / min, dry air atmosphere, 1000°C. I set it to 10 hours.

[0532] In step S15, the processing conditions for the bead mill are lithium manganese composite oxide 600 For g, the temperature was set to 4 m / s for 25 hours. After that, it was dried at 75°C and then at 100°C. It was dried.

[0533] In step S16, the firing conditions are 10 L / min, dry air atmosphere, and 800°C. The time was set to 3 hours. The powder obtained in step S16 is designated as sample A4.

[0534] (Step S17) Next, a layer containing carbon was formed on the obtained sample A4. First, the aqueous dispersion of graphene oxide... The solution was prepared. The water was divided into three equal parts, and a kneading machine was used to mix each time it was added to the graphene oxide. Mix and knead to prepare a dispersion solution of graphene oxide. Add to 10 g of graphene oxide The total volume of water was 150 ml. Next, sample A4 and water were added to the prepared aqueous dispersion solution. The mixture was then kneaded to a solid consistency. The amount of sample A4 added was 500g, and the amount of water was 200ml. Next, the resulting mixture was dried at 70°C using a ventilated drying oven, and then crushed in an alumina mortar. Thus, sample B4 was obtained, which is a lithium manganese composite oxide coated with graphene oxide.

[0535] (Step S18) Next, the graphene oxide in sample B4 was reduced. Ascorbyl was used as the reducing agent. An acid was used, and an 80% by volume aqueous ethanol solution was used as the solvent. Graphene oxide was covered. The weight of the overturned lithium manganese composite oxide was 16.87 wt% ascorbic acid and A reducing solution was prepared by adding 3.9 wt% lithium hydroxide. The resulting sample B4 was then reduced in the reducing solution. It was placed in a container and treated at 60°C for 3 hours to reduce it.

[0536] (Step S19) Next, the solvent was separated from the obtained solution using a centrifuge, and the separated liquid was discarded. Afterward, the process of adding pure water for washing, centrifuging, and discarding the separated liquid was repeated five times. The centrifugation speed was set to 6000 rpm, and each cycle lasted 3 minutes. Next, the solvent was separated. Pure water was added to the sample to obtain solutions of four different concentrations. The solutions of different concentrations were designated as Solution A and Solution B. Let C and D be the two terms.

[0537] Solution A was prepared by adjusting the amount of pure water relative to sample B4 to 10 g / L. Solution B Solution C is prepared to be 100g / L, Solution D to be 300g / L, and Solution D to be 500g / L. Prepared. Then, solutions A through D were heated to 60°C. The temperature at the inlet of the spray drying apparatus. The temperature was set to 150°C, and each solution was subjected to spray drying.

[0538] Next, each solution was treated by spray drying, and the resulting powders were then heated at 170°C for 10 minutes. The samples were dried under reduced pressure for a specified time. Using a solution in which each dried sample was dispersed in NMP, the particle size distribution was measured. The following measurements were taken. Note that the particle size measured here is mainly that of secondary particles. Particle size distribution A laser diffraction particle size distribution analyzer (SALD-2200 model, manufactured by Shimadzu Corporation) was used for the measurement. The particle size was calculated using the laser diffraction and scattering method. From the obtained results, the average particle size was determined. Diameter, and D90 (In the cumulative particle amount curve of particle size distribution measurement results, the cumulative amount is 90%). The value of the particle size (at which it occupies) was evaluated. Figure 4 shows a plot with particle size on the x-axis and frequency on the y-axis. This is shown in 2. The results for the sample recovered from solution A are shown by a solid line, solution B by a dashed line, and solution C by a dashed line. Solution D is shown by the dashed lines.

[0539] The average particle size was 3.26 μm for the sample recovered from solution A, 2.45 μm for solution B, and C The particle size of solution D was 3.84 μm, and the particle size of solution D was 3.40 μm.

[0540] Furthermore, the D90 values ​​were 7.94 μm for the sample recovered from solution A and 9.73 μm for solution B. The diametrically opposed levels of solution C were 13.92 μm and solution D was 13.18 μm.

[0541] The samples recovered from solutions C and D had a large D90 value of 13 μm or more, as shown in Figure 4. As shown in 2, a tail is visible in regions larger than 20 μm.

[0542] From Figure 43(A) solution A, (B) solution B, Figure 44(A) solution C, and (B) solution D The results of observing the obtained samples by SEM are shown. In solutions B to D, the particle size was 15 μm. Secondary particles exceeding m were observed.

[0543] From the results in Figures 42 to 44, the concentration of the solution used during the spray-drying process is, for example, 10 A concentration of 0 g / L or less is preferred, and 10 g / L or less is considered more preferable. [Examples]

[0544] In this example, the release of gas from the battery during charging and discharging was measured.

[0545] <Fabrication of the positive electrode> A positive electrode active material for use in a storage battery was synthesized. Steps S11 to S11 shown in Example 6 I did 14.

[0546] (Step S15) Next, a crushing process was performed. The processing conditions for the bead mill were lithium manganese composite oxide 48 After processing 0g at a peripheral speed of 8m / s for 20 minutes, it was processed again at 12m / s for 10 hours. Then, It was dried.

[0547] (Step S16) Next, firing was performed. The firing conditions were 10 L / min, dry air atmosphere, 800°C, 3 Time was set. The powder obtained in step S16 is designated as sample A5.

[0548] (Step S17) Next, a layer containing carbon was formed on the obtained sample A5. First, water and graphene oxide were mixed. A mixture was prepared to create an aqueous dispersion of graphene oxide. (2g graphene oxide, total amount of water added) The volume was 10 mL. Next, 100 g of sample A5 and 20 ml of water were added to the prepared aqueous dispersion solution. L was added and the mixture was kneaded into a solid mass. Next, the resulting mixture was dried and then crushed in an alumina mortar. Then, sample B5 was obtained, which is a lithium manganese composite oxide coated with graphene oxide.

[0549] (Step S18) Next, the graphene oxide containing sample B5 was reduced. Ascorbyl was used as the reducing agent. An acid was used, and a mixed solvent of ethanol and water was used as the solvent. In the mixed solvent, ethanol The concentration of the substance was 80% by volume. Lithium manganese composite oxide coated with graphene oxide. For the weight of [the substance], 16.87 wt% ascorbic acid and 3.9 wt% lithium hydroxide are added. A reducing solution was prepared. The obtained sample B5 was placed in the reducing solution and treated at 60°C for 3 hours. I did it.

[0550] (Step S19) Next, the obtained solution was filtered to separate the solvent and obtain the sample. Afterward, it was dried to obtain sample C. I got a 5.

[0551] A positive electrode was fabricated using the obtained sample C5. Sample C5 was used as the active material, and a conductive additive was used. Acetylene black (AB) was used, and PVdF was used as the binder. Active material The composition of AB and PVdF is active material:AB:PVdF=90:5:5 (weight A slurry was prepared using NMP as the solvent, with the concentration set to %).

[0552] Next, the prepared slurry is placed on a 20 μm thick aluminum undercoat. The coating was applied to one side of the foil. Next, it was heated to evaporate the solvent. Then, it was pressed. Subsequently, heat treatment was performed. The heat treatment conditions were 1 kPa pressure, 250°C, and 10 hours.

[0553] The positive electrode obtained through the above process is designated as positive electrode X4. The amount of active material supported in positive electrode X4 is 6.5 mg / cm³ 2 That was the case.

[0554] <Fabrication of the negative electrode> Next, a negative electrode was fabricated using graphite as the active material. Graphite, carbon fiber, CMC and SBR A slurry was prepared by mixing water and graphite using a kneader. Graphite, carbon fiber, CMC and The ratio of SBR is graphite:carbon fiber:CMC:SBR = 96:1:1:2 (weight%). That's what I decided.

[0555] Next, the prepared slurry was applied to one side of a rolled copper foil with a thickness of 18 μm. Then, it was dried. The negative electrode active material layer was formed by performing the following procedure. The resulting negative electrode is referred to as negative electrode Y3. The substance load is 8.8 mg / cm³. 2 That was the case.

[0556] <Fabrication of reference electrodes> Next, a positive electrode was fabricated using LiFePO4 as the active material as a reference electrode. Aluminum foil was used. The fabricated positive electrode is designated as positive electrode X5. The amount of active material supported on positive electrode X5 is 1 0.8 mg / cm³ 2 That was the case.

[0557] <Fabrication of the negative electrode> Next, a negative electrode was fabricated using graphite as the active material. Graphite, carbon fiber, CMC and SBR A slurry was prepared by mixing water and graphite using a kneader. Graphite, carbon fiber, CMC and The ratio of SBR is graphite:carbon fiber:CMC:SBR = 96:1:1:2 (weight%). Next, the prepared slurry was applied to one side of a rolled copper foil with a thickness of 18 μm. Then, drying was performed to form a negative electrode active material layer. The obtained negative electrode is referred to as negative electrode Y4. The amount of active material carried is 7.5 mg / cm³. 2 That was the case.

[0558] <Battery manufacturing> Next, a storage battery C3 was constructed using six of the fabricated positive electrodes X4 and six of the negative electrodes Y3. A storage battery C4 was fabricated using six positive electrodes X5 and six negative electrodes Y4, which serve as reference electrodes.

[0559] Aluminum film covered with heat-sealed resin is used as the outer casing for batteries C3 and C4. It was used. The electrolyte was LiPF6, and the solvent was EC:DEC:EM. A mixed solvent prepared by mixing C in a volume ratio of 3:6:1 was used, with PS and VC as additives. They were there. Also, PP was used for the separator.

[0560] The positive electrode, negative electrode, and separator consist of six sets of positive electrode active material layers and negative electrode active material layers, and the separator is... They were stacked facing each other with an intervening barrier.

[0561] Next, the fabricated battery C3 was charged and discharged. At 25°C, the current density was 0.1C (1 After constant current charging at 7mA / g and an upper limit of 4.6V, 0.01C was applied at a constant voltage of 4.6V. Charging was performed as the termination condition. Subsequently, constant current discharge was performed at a lower limit of 2.0V. The discharge capacity was The value was 207 mAh / g. By using particles according to one embodiment of the present invention as a positive electrode active material... High capacity was obtained.

[0562] In addition, battery C4 was also charged and discharged. At 25°C, the current density was 0.01C. After constant current charging at 24mA / g and an upper limit of 3.2V, constant current charging at 0.1C and an upper limit of 4V is performed. The electric current was applied. Afterwards, a constant current discharge was performed at 0.2C and a lower limit of 2.0V. Next, 0.2C, After constant current charging with an upper limit of 4V, constant current discharge was performed at 0.2C with a lower limit of 2V. Here, the battery was charged. For both batteries C3 and C4, the current density and capacity were standardized per unit weight of positive electrode active material. The discharge capacity of the eye was 109 mAh / g, and the discharge capacity of the second discharge was 123 mAh / g.

[0563] Next, gases were collected from inside battery C3 and battery C4 after charging and discharging.

[0564] Next, each of the collected gases is processed using GC-TCD (Gas Chromatography). Measured using a y-Thermal Conductivity Detector. The types and relative abundances of the gases obtained are shown in Table 4. Here in Table 4, H2, O2, N2, C The sum of the relative abundances of the eight gases O, CH4, CO2, C2H4, and C2H6 is 100. The ratio is shown as a percentage. Here, for gases where no numerical value is given, it is below the detection limit, or This shows a case where CO2 was detected but in a trace amount and difficult to quantify. Here, CO2 from battery C4 was not detected. Although some was produced, it was only a small amount.

[0565] [Table 4]

[0566] Table 4 shows that in battery C4, which uses LiFePO4 as the positive electrode, the CO2 value was negligible. In contrast, in battery C3, which uses sample C5 as the positive electrode, CO2 accounts for 30% of the eight types of gases. It showed a high value. In addition, 45% hydrogen was detected in battery C3 and 64% in battery C4. The total amount of gas produced was greater with battery C3.

[0567] Battery C3 has a high charge and discharge potential, increasing its energy density as a battery. This is preferable because it allows for the following: On the other hand, when the charging and discharging potentials are high, oxidation of the electrolyte occurs. Decomposition can occur easily. In the case of battery C3, the upper limit of the charging voltage is 4.6V, which is high. It is thought that the electrolyte decomposed during the charging process, making it prone to generating gases such as CO2. Therefore, when using the particles of one embodiment of the present invention as a positive electrode active material, Examples 4 and 5 As shown, this occurs when the battery is opened after the positive electrode of the battery has been charged and discharged. By releasing the gas and then reassembling the battery, the gas generated by the battery is eliminated. This is preferable because it can minimize the impact on the characteristics. [Examples]

[0568] In this example, coating with graphene oxide and treatment with a reducing solution affect the characteristics of the storage battery. We investigated the effects of this.

[0569] First, particles containing lithium manganese composite oxide were prepared. The steps are shown in Example 6. Steps S11 through S14 were performed.

[0570] (Step S15) Next, a crushing process was performed. The processing conditions for the bead mill were lithium manganese composite oxide 24 After treating 0g at a peripheral speed of 8m / s for 10 minutes, it was treated at 4m / s for 10 hours. Then, drying... Drying was performed. The powder obtained here is designated as sample A6.

[0571] Next, the conditions for treating sample A6 with a reducing solution (sample B6), and the oxidation graph. Conditions for coating with graphene (sample C6), conditions for coating with graphene oxide and performing reduction treatment (sample D6) The following samples were prepared.

[0572] (Step S17) A layer containing carbon was formed on sample A6. First, water and graphene oxide were mixed, and then the graphene oxide was formed. A dispersion solution of graphene was prepared. The total volume of water added was 3 mL and the amount of graphene oxide was 0.3 g. Next, 15g of sample A6 and 3mL of water were added to the prepared aqueous dispersion solution, and a paste was formed. The process was carried out. Next, the resulting mixture was dried and then crushed in an alumina mortar to obtain sample C6.

[0573] (Step S18 / S19) Next, samples C6 and A6 were treated with an ascorbic acid solution. A mixed solvent of ethanol and water was used as the solvent. In the mixed solvent, the concentration of ethanol It was 80% by volume. Ascorbic acid was approximately 1% of the weight of sample C6 and sample A6. A reducing solution was prepared by adding 7 wt% of the substance and approximately 4 wt% of lithium hydroxide.

[0574] Sample C6 was placed in a reducing solution and treated at 60°C for 3 hours. The solution was then filtered and dried. Sample D6 was obtained by performing the following procedure. Additionally, sample A6 was placed in a reducing solution and treated at 60°C for 3 hours. The solution was then filtered and dried to obtain sample B6.

[0575] <Electrode fabrication> The obtained samples A6, B6, C6, and D6 were used as active materials to create electrodes. It was manufactured using acetylene black (AB) as a conductive additive and PVd as a binder. F was used. The ratio of active material, AB, and PVdF was active material:AB:PVdF = 90:5 A slurry was prepared using NMP as the solvent, with a weight of 5%.

[0576] Next, the prepared slurry is placed on a 20 μm thick aluminum undercoat. The foil was coated on one side. Next, it was dried. Then, it was pressed. After that, it was heat-treated. The heat treatment conditions were 1 kPa pressure, 250°C, and 10 hours.

[0577] The electrodes obtained using samples A6, B6, C6, and D6 are each designated as electrode A. 6. Let's call them electrodes B6, C6 and D6. Electrode A6, electrode B6, electrode C6 and The amount of active material loaded onto electrode D6 is 3.2 mg / cm³. 2 , 4.1 mg / cm³ 2 , 3.0 mg / cm 2 and 3.7 mg / cm³ 2 That was the case.

[0578] <Half-cell characteristics> Next, half-cells were fabricated using the obtained electrodes A6, B6, C6, and D6. Coin cells were used for this. Lithium was used for the counter electrode of the half cell. Also, electrolysis The solution uses LiPF6 as the electrolyte and a ratio of EC and DEC, which are aprotic organic solvents. A mixed solution prepared by mixing in a volume ratio of 1 was used. Polypropylene was used as the separator. PP was used.

[0579] Next, the charge-discharge cycle evaluation of the fabricated half-cell was performed. Charging was performed using a constant current of 0.1C. The procedure was performed with an upper voltage limit of 4.8V, and discharge was carried out with a constant current of 0.1C and a lower voltage limit of 2V. Figure 45 shows the results. The graph shows the number of charge-discharge cycles on the horizontal axis and the discharge capacity on the vertical axis.

[0580] Electrode A6 that was not coated with graphene oxide or treated with ascorbic acid solution. However, a significant decrease in volume was observed from the third cycle onwards, while using ascorbic acid solution... In electrode B6, which underwent this treatment, the decrease in capacity was suppressed, and the capacity at the 10th cycle was the same as the initial capacity. The capacity was 88%. Furthermore, in electrode C6, which was coated with graphene oxide, the 10-size The volume of the crust is more than 90% of the initial volume, further suppressing the volume decrease, and graphene oxide In electrode D6, which was treated with a reducing solution after coating, the volume at the 10th cycle was The highest value was obtained, at 98% of the initial capacity.

[0581] Based on the above, when particles according to one embodiment of the present invention are treated with an ascorbic acid solution, For example, a region that is more stable than the interior may be formed on at least a portion of the surface of the particle. It is possible. Also, a coating layer having graphene oxide or reduced graphene is The overturned region is more stable compared to the interior region of the particles, improving the stability of battery charging and discharging. This suggests that they did so. [Examples]

[0582] In this example, particles having a lithium manganese composite oxide according to one aspect of the present invention were produced. The characteristics were then evaluated. The manufacturing procedure will be explained based on the flowchart in Figure 1.

[0583] <Synthesis> First, particles containing lithium manganese composite oxide were fabricated.

[0584] (Step S11) First, we use Li2CO3, MnCO3, and NiO as starting materials. The ratio (molar ratio) is Li2CO3:MnCO3:NiO = 0.84:0.8062:0 The weight was measured to be 0.318.

[0585] (Step S12) Next, ethanol was added to the starting material and then mixed using a bead mill. The peripheral speed in the processing chamber was set to 10 m / s.

[0586] (Step S13) Next, the mixed raw materials were subjected to heat treatment. The heat treatment was carried out in an atmospheric environment, at a heating temperature. By performing the process at 75°C, the ethanol contained in the mixed raw materials is evaporated, and the mixture We obtained the raw materials.

[0587] (Step S14) Next, the mixed raw materials were placed in the crucible and fired. The firing process involved drying at a flow rate of 10 L / min. By firing in an air atmosphere at a temperature of 1000°C for a firing time of 10 hours, A lithium manganese composite oxide was synthesized.

[0588] (Step S15) Next, a crushing process is performed to dissolve the sintered lithium manganese composite oxide in which the primary particles have been sintered. The process was carried out. The crushing treatment involved adding ethanol to the sintered lithium manganese composite oxide, and then... The processing chamber of the mill was rotated at a peripheral speed of 8 m / s for 10 minutes, and then rotated at 4 m / s for 10 hours. The process was carried out to obtain a powdered lithium manganese composite oxide.

[0589] (Step S16) Next, the lithium manganese composite oxide after the crushing process was subjected to heat treatment. By performing the procedure at 75°C in an air atmosphere, the ethanol contained in the mixed raw materials is removed. The urethane was evaporated. Next, the obtained lithium manganese composite oxide was placed in a crucible and calcined. The firing conditions were 700°C for 3 hours in a dry air atmosphere of 10 L / min. After calcination, the resulting powder was designated as Sample A. Sample A has the compositional formula Li 1.68 Mn 0.806 2Ni 0.318 It is represented as O3, but the composition may deviate from this.

[0590] <Coating layer> Next, a layer containing carbon was formed on the obtained sample A. First, 0.1 g of graphene oxide was added. In contrast, the mixture is kneaded using a kneader to obtain a dispersion solution of graphene oxide, with the amount of water being 1g. I made it.

[0591] (Step S17) Next, sample A was added to the prepared aqueous dispersion and mixed. Here, graphene oxide was added. The ratio of sample A to sample A was adjusted to 50g for every 1g of sample A. The resulting mixture was then measured using a bell jar. After being dried under reduced pressure at 50°C, the lithium was crushed in an alumina mortar and pestle and coated with graphene oxide. Sample B, a manganese composite oxide, was obtained.

[0592] (Step S18) Next, the graphene oxide coated on the surface of the lithium manganese composite oxide was reduced. Ascorbic acid was used as the agent, and a mixed solvent of ethanol and water was used as the solvent. In the solvent, the concentration of ethanol was 80% by volume. Lithium coated with graphene oxide The ummanganese complex oxide was mixed with 16.87 wt% ascorbic acid and lysyl hydroxide. A reducing solution was prepared by adding 3.9 wt% of lithium. The resulting powder was placed in the reducing solution and heated at 60°C. It was processed for 3 hours and then reduced.

[0593] (Step S19) Next, the obtained solution was filtered by suction filtration. For filtration, a filtration system with a particle retention capacity of 1 μm was used. Filter paper was used. Afterwards, it was washed and filtered again.

[0594] Next, add pure water to the sample from which the solvent has been separated to adjust the concentration to 15 g / l, and then the solution The obtained solution was then heated to 60°C and supplied to a spray drying apparatus. The material was heated to 0°C and then spray-dried.

[0595] Next, the powder obtained by spray drying was dried under reduced pressure at 170°C for 10 hours. did.

[0596] Next, the obtained powder was ground in a mortar. Then, it was dried at 170°C under reduced pressure for 10 hours. went.

[0597] Through the above process, a lithium manganese composite oxide powder with graphene formed on its surface is obtained. Sample (C) was prepared.

[0598] <Electrode fabrication> Next, electrodes were fabricated using the obtained sample C. Sample C was used as the active material, and a conductive additive was used. Acetylene black (AB) was used as the binder, and PVdF was used as the binder.

[0599] First, PVdF, AB, and the polar solvent NMP (N-methyl-2-pyrrolidone) The mixture was kneaded using a kneader to obtain a slurry. The composition of the electrode mixture was C:A by weight ratio. B:PVdF = 90:5:5

[0600] Next, the electrode mixture composition was applied onto the aluminum foil, which served as the current collector. The surface of the aluminum foil was pre-coated with an undercoat. Then, it was dried in a ventilated drying oven at 80°C. Then, it was dried for 30 minutes. The electrode obtained here will be called electrode X1. Using a roll press machine, The electrodes were pressed. The film thickness was reduced by 20% compared to the film thickness after electrode coating. The press pressure was adjusted, and the press temperature was set to 120°C.

[0601] Subsequently, electrode X1 was subjected to heat treatment. The heat treatment conditions were a reduced pressure atmosphere (1 kPa), 2 The sample was treated at 50°C for 10 hours. Electrode X2 was obtained through the above process.

[0602] <Half-cell characteristics> Next, half-cells were fabricated using the obtained electrodes X1 and X2. The cells contained carp A half-cell was used. Lithium was used as the counter electrode of the half-cell. The electrolyte was electrolytic. LiPF6 is used as the substrate, and the aprotic organic solvents EC and DEC are mixed in a 1:1 volume ratio. A mixed solution prepared using the above was used. Polypropylene (PP) was used as the separator. there was.

[0603] Next, the charge and discharge characteristics were measured at 25°C. Charging was performed with a constant current of 30 mA / g, and above The procedure was performed with a voltage limit of 4.8V, and discharge was carried out with a constant current of 30mA / g and a lower voltage limit of 2V. The charge and discharge curves are shown in Figure 52. The dashed line represents the charge and discharge curve of electrode X1, and the solid line represents the charge and discharge curve of electrode X2. The results are shown below. It was found that a higher capacity could be obtained with electrode X2, which was heat-treated. . [Examples]

[0604] In this example, the results of XPS analysis of an electrode according to one embodiment of the present invention will be described.

[0605] <Synthesis> First, particles containing lithium manganese composite oxide are fabricated following the steps shown in Figure 1. did.

[0606] (Step S11) First, we use Li2CO3, MnCO3, and NiO as starting materials. The ratio (molar ratio) is Li2CO3:MnCO3:NiO = 0.84:0.8062:0 The weight was measured to be 0.318.

[0607] (Step S12) Next, ethanol was added to the starting material and then mixed using a bead mill. The peripheral speed in the processing chamber was set to 10 m / s.

[0608] (Step S13) Next, the mixture was obtained by heating it to a temperature of 100°C or lower to evaporate the ethanol.

[0609] (Step S14) Next, the mixed raw materials were placed in the crucible and fired. The firing process involved drying at a flow rate of 10 L / min. Under an air atmosphere, the firing temperature was 1000°C and the firing time was 10 hours.

[0610] (Step S15) Next, the lithium manganese composite oxide, which was formed from sintered primary particles, was subjected to a crushing treatment. This involves adding ethanol to 600g of sintered lithium manganese composite oxide, and then... The processing chamber of the mill was subjected to a 10-hour treatment at a peripheral speed of 12 m / s.

[0611] (Step S16) Next, the ethanol was evaporated by heating to a temperature below 100°C. Then, the obtained lithium The ummanganese composite oxide was placed in a crucible and calcined. The calcination conditions were 10 L / min dry The mixture was heated to 800°C for 3 hours in a dry air atmosphere. After firing, the resulting powder was mixed with sample A2. Sample A2 has the composition formula Li 1.68 Mn 0.8062 Ni 0.318 It is represented as O3. However, this composition may deviate from the actual composition.

[0612] <Coating layer> Next, a carbon-containing layer was formed on the surface of the obtained sample A2. First, graphene oxide 1 Mix the ingredients in a kneader in a ratio of 15 mL of water to 1 g of graphene oxide. A dispersion solution was prepared.

[0613] (Step S17) Next, sample A2 was added to the prepared aqueous dispersion and mixed. Here, graphite oxide The ratio of sample A2 to 1g of n was adjusted to 50g. The resulting mixture was then placed in a bell jar. After being dried under reduced pressure at 70°C, it was crushed in an alumina mortar and pestle, and then coated with graphene oxide. Sample B2, a thium-manganese composite oxide, was obtained.

[0614] (Step S18) Next, the graphene oxide coated on the surface of the lithium manganese composite oxide was reduced. Ascorbic acid was used as the agent, and a mixed solvent of ethanol and water was used as the solvent. In the solvent, the concentration of ethanol was 80% by volume. Lithium coated with graphene oxide Ascorbic acid is present in 16.87 weight percent relative to the weight of the ummanganese complex oxide. A reducing solution was prepared by adding 3.9% lithium hydroxide. The resulting powder was then reduced. The sample was placed in a solution and reduced by treating it at 60°C for 3 hours.

[0615] (Step S19) Next, the obtained solution was treated with a centrifuge to separate the solvent from the sample. Next, add pure water to the sample from which the solvent has been separated to adjust the concentration to 24 g / l, and then the solution The obtained solution was then heated to 60°C and then fed into the supply port of the spray dryer. The material was heated to 0°C and then spray-dried.

[0616] Next, the powder obtained by spray drying was dried under reduced pressure at 170°C for 10 hours. did.

[0617] Through the above process, a lithium manganese composite oxide powder with graphene formed on its surface is obtained. Sample C2 was prepared.

[0618] <Electrode fabrication> Next, electrodes were fabricated using the obtained sample C2. Sample C2 was used as the active material, acetylene black (AB) was used as the conductive assistant, and PVdF was used as the binder.

[0619] First, PVdF, AB, and the polar solvent NMP (N-methyl-2-pyrrolidone) were kneaded using a kneader to obtain a slurry. The formulation of the electrode mixture composition was such that the weight ratio of sample C: A:B:PVdF = 90:5:5.

[0620] Next, the electrode mixture composition was coated on an aluminum foil serving as a current collector. Note that the surface of the aluminum foil was pre-coated in advance. Then, it was dried in a ventilation drying oven at 80 °C for 30 minutes. The electrode obtained here was designated as electrode X3. Next, the electrode X3 was pressed using a roll press machine. The pressing pressure was adjusted so as to reduce the film thickness by 20% with respect to the film thickness after electrode coating was performed. Also, the pressing temperature was set at 120 °C.

[0621] Thereafter, heat treatment was performed on electrode X3. The electrode subjected to heat treatment at 1 kPa, 170 °C for 10 hours was designated as electrode X4. Also, the electrode subjected to heat treatment at 1 kPa, 250 °C for 10 hours was designated as electrode X5.

[0622] <XPS analysis> XPS analysis of the obtained electrodes X3, X4, and X5 was performed. The narrow spectra of Li1s, O1s, C1s and F1s are shown in FIGS. 53(A), (B), FIG. 54(A), and (B). Also, the abundance ratios of Ni, Mn, Li, O, C, and F are shown in Table 5. In Table 5, the numerical values were normalized such that the sum of the abundance ratios of the six elements became 100 atomic%. The numerical values were normalized so that the sum of the abundance ratios of the six elements was 100 atomic%.

[0623] [Table 5]

[0624] Figure 53(A) shows that the peak intensity at electrode X5 is greater than that at X3 and X4, due to factors such as LiF. It is increasing. From Figure 54(A), the heat treatment of electrodes X3, X4, and X5 further increases The high temperature of the heat treatment reduces the number of CF2 and O-CF bonds. From Figure 54(B), X 3. X4, X5 and the heat treatment of the electrodes, and further increasing the temperature of the heat treatment, the metal-F bond This is increasing. Therefore, by heat treatment of the electrodes, and further increasing the temperature, PVdF The contained CF2, the O-CF bond is broken, and the Li of sample C, the CF2 bond and O-CF bond It is thought that a Li-F bond was formed between the F atoms that were created when the bond was broken. Li-F bond The formation of this layer may have improved the strength of the electrode. [Examples]

[0625] In this embodiment, a half-cell was fabricated using an electrode according to one aspect of the present invention, and its characteristics were evaluated. Ta.

[0626] <Electrode fabrication> An electrode was fabricated using sample C2 obtained using the process shown in Example 2. Using sample C2, acetylene black (AB) was used as a conductive additive, and as a binder... Polyimide was used.

[0627] First, we have a precursor of polyimide (PI), and AB and a polar solvent called NMP (N-methyl-2 -Pyrrolidone) was kneaded using a kneader to obtain a slurry. The composition of the electrode mixture was as follows: The sample was prepared so that the weight ratio of C:AB:PI = 90:5:5. The N of the polyimide precursor was also adjusted. MP solution was used. The solution concentration was 13.7 weight%.

[0628] Next, the electrode mixture composition was applied onto the aluminum foil, which served as the current collector. The surface of the aluminum foil was pre-coated with an undercoat. Then, it was dried in a drying oven at 80°C for 30 minutes. The mixture was heated and the solvent evaporated. The electrode obtained here is designated as electrode Z1. Next, the electrode A press conference was held.

[0629] Subsequently, electrode Z1 was subjected to heat treatment at 1 kPa and 300°C for 10 hours. The resulting electrode was then electrostatically treated. Let's call it extreme Z2.

[0630] <Half-cell characteristics> Next, a half-cell was fabricated using electrode Z2. The fabrication conditions for the half-cell were actually... The same conditions as in Example 1 were used.

[0631] Next, the charge and discharge characteristics were measured at 25°C. Charging was performed with a constant current of 30 mA / g, and above The procedure was performed with a voltage limit of 4.8V, and discharge was carried out with a constant current of 30mA / g and a lower voltage limit of 2V. The charge-discharge curve is shown in Figure 55. Electrode Z2, which was heat-treated at a high temperature of 300°C, It was found that it can achieve a very high discharge capacity of 281 mAh / g. [Explanation of Symbols]

[0632] 100 electrodes 101 Current collector 102 Active material layer 120a Graphene 131 areas 132 areas 133 areas 141 particles 142 areas 143 areas 300 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 Separator 500 Battery 501 Positive electrode current collector 502 Positive electrode active material layer 503 Positive electrode 504 Negative electrode current collector 505 Negative electrode active material layer 506 negative electrode 507 Separator 508 Electrolyte 509 Exterior 510 Positive lead electrode 511 Negative lead electrode 512 Welding Area 513 Curved section 514 Sealing part 600 Battery 601 Positive Cap 602 Battery Can 603 Positive terminal 604 Positive electrode 605 Separator 606 negative electrode 607 Negative terminal 608 Insulating board 609 Insulating board 611 PTC element 612 Safety valve mechanism 900 Circuit Boards 910 Labels 911 terminal 912 Circuit 913 Storage Battery 914 Antenna 915 Antenna 916 layers 917 layers 918 Antenna 919 terminal 920 Display device 921 Sensor 922 terminals 951 terminal 952 terminals 981 film 982 film 990 Battery 991 Exterior 992 Exterior 993 Wound body 994 negative electrode 995 positive electrode 996 Separator 997 Lead Electrode 998 Lead Electrode 1700 curved surface 1701 Plane 1702 Curve 1703 Radius of curvature 1704 Center of curvature 1800 Center of curvature 1801 film 1802 radius of curvature 1803 film 1804 Radius of curvature 1805 Electrodes, electrolytes, etc. 7100 Portable Display Device 7101 enclosure 7102 Display section 7103 Operation Buttons 7104 Energy storage device 7200 Mobile Information Terminal 7201 enclosure 7202 Display section 7203 Band 7204 Buckle 7205 Operation Buttons 7206 Input / output terminal 7207 Icons 7300 display device 7304 Display section 7400 mobile phones 7401 enclosure 7402 Display section 7403 Operation Buttons 7404 External connection port 7405 Speaker 7406 Microphone 7407 Energy storage device 7408 Lead Electrode 7409 Current collector 8000 display device 8001 enclosure 8002 Display section 8003 Speaker section 8004 Energy Storage Device 8021 Charging device 8022 Cable 8024 Energy storage device 8100 Lighting device 8101 enclosure 8102 Light source 8103 Energy Storage Device 8104 Ceiling 8105 Side wall 8106 floor 8107 Window 8200 indoor unit 8201 enclosure 8202 Air outlet 8203 Energy storage device 8204 Outdoor unit 8300 Electric Refrigerator / Freezer 8301 enclosure 8302 Refrigerator door 8303 Freezer door 8304 Energy storage device 8400 automobiles 8401 Headlight 8406 Motor 8500 automobiles 9600 Tablet devices 9625 Switch 9626 Switch 9627 Power switch 9628 Operation switch 9629 Fastener 9630 cabinet 9630a enclosure 9630b enclosure 9631 Display section 9631a Display section 9631b Display section 9632a area 9632b area 9633 Solar Cell 9634 Charge / Discharge Control Circuit 9635 Energy Storage Unit 9636 DC-DC converter 9637 Converter 9638 Operation Keys 9639 button 9640 Moving parts S1 Control signal S2 control signal S3 Transformed signal BT00 Power storage device BT01 terminal pair BT02 terminal pair BT03 Switching Control Circuit BT04 Switching Circuit BT05 Switching Circuit BT06 Transformer Control Circuit BT07 Transformer Circuit BT08 battery part BT09 battery cell BT10 Transistor BT11 bus BT12 bus BT13 Transistor BT14 Current Control Switch BT15 bus BT16 bus BT17 Switch vs BT18 Switch vs BT21 Transistor Pair BT22 Transistor BT23 Transistor BT24 bus BT25 bus BT31 transistor pair BT32 Transistor BT33 Transistor BT34 bus BT35 bus BT41 Battery Control Unit BT51 Isolated DC-DC Converter BT52 Switch Section BT53 Transformer Section

Claims

1. A lithium-ion secondary battery having a positive electrode, The positive electrode comprises a current collector and an active material layer on the current collector. The active material layer comprises a composite oxide containing lithium and manganese, and graphene covering at least a portion of the composite oxide. The composite oxide has a first region and a second region, The second region is located on the surface side of the first region and in the surface layer of the composite oxide, The first region and the second region each contain lithium and oxygen, The first region and the second region each contain manganese and an element represented by M, The element represented by M is a metallic element selected from Ni, Ga, Fe, Mo, In, Nb, Nd, Co, Sm, Mg, Al, Ti, Cu, or Zn, Si, or P. The first region has a first crystal which has a layered rock salt structure, The second region has a second crystal which has a layered rock salt structure. The orientation of the first crystal is different from the orientation of the second crystal. The ratio of the number of oxygen atoms to the sum of the number of manganese atoms and the element represented by M in the second region is smaller than the ratio of the number of oxygen atoms to the sum of the number of manganese atoms and the element represented by M in the first region. The graphene in question is a lithium-ion secondary battery, including multilayer graphene.

2. A lithium-ion secondary battery having a positive electrode, The positive electrode comprises a current collector and an active material layer on the current collector. The active material layer comprises a composite oxide containing lithium and manganese, and graphene covering at least a portion of the surface of the composite oxide. The composite oxide has a first region and a second region, The second region is located on the surface side of the first region and in the surface layer of the composite oxide, The first region and the second region each contain lithium and oxygen, The first region and the second region each contain manganese and an element represented by M, The element represented by M is a metallic element selected from Ni, Ga, Fe, Mo, In, Nb, Nd, Co, Sm, Mg, Al, Ti, Cu, or Zn, Si, or P. The first region has a first crystal which has a layered rock salt structure, The second region has a second crystal which has a layered rock salt structure. The orientation of the first crystal is different from the orientation of the second crystal. The ratio of the number of oxygen atoms to the sum of the number of manganese atoms and the element represented by M in the second region is smaller than the ratio of the number of oxygen atoms to the sum of the number of manganese atoms and the element represented by M in the first region. The graphene in question is a lithium-ion secondary battery, including multilayer graphene.

3. A lithium-ion secondary battery having a positive electrode, The positive electrode comprises a current collector and an active material layer on the current collector. The active material layer comprises a composite oxide containing lithium and manganese, and graphene covering at least a portion of the cleavage surface of the composite oxide. The composite oxide has a first region and a second region, The second region is located on the surface side of the first region and in the surface layer of the composite oxide, The first region and the second region each contain lithium and oxygen, The first region and the second region each contain manganese and an element represented by M, The element represented by M is a metallic element selected from Ni, Ga, Fe, Mo, In, Nb, Nd, Co, Sm, Mg, Al, Ti, Cu, or Zn, Si, or P. The first region has a first crystal which has a layered rock salt structure, The second region has a second crystal which has a layered rock salt structure. The orientation of the first crystal is different from the orientation of the second crystal. The ratio of the number of oxygen atoms to the sum of the number of manganese atoms and the element represented by M in the second region is smaller than the ratio of the number of oxygen atoms to the sum of the number of manganese atoms and the element represented by M in the first region. The graphene in question is a lithium-ion secondary battery, including multilayer graphene.

4. A lithium-ion secondary battery having a positive electrode, The positive electrode comprises a current collector and an active material layer on the current collector. The active material layer comprises a composite oxide containing lithium and manganese, and graphene covering at least a portion of the composite oxide. The composite oxide has a first region and a second region, The second region is located on the surface side of the first region and in the surface layer of the composite oxide, The first region and the second region each contain lithium and oxygen, The first region and the second region each contain manganese and an element represented by M, The element represented by M is a metallic element selected from Ni, Ga, Fe, Mo, In, Nb, Nd, Co, Sm, Mg, Al, Ti, Cu, or Zn, Si, or P. The first region has a first crystal which has a layered rock salt structure, The second region has a second crystal which has a spinel-type structure. The ratio of the number of oxygen atoms to the sum of the number of manganese atoms and the element represented by M in the second region is smaller than the ratio of the number of oxygen atoms to the sum of the number of manganese atoms and the element represented by M in the first region. The graphene in question is a lithium-ion secondary battery, including multilayer graphene.

5. A lithium-ion secondary battery having a positive electrode, The positive electrode comprises a current collector and an active material layer on the current collector. The active material layer comprises a composite oxide containing lithium and manganese, and graphene covering at least a portion of the surface of the composite oxide. The composite oxide has a first region and a second region, The second region is located on the surface side of the first region and in the surface layer of the composite oxide, The first region and the second region each contain lithium and oxygen, The first region and the second region each contain manganese and an element represented by M, The element represented by M is a metallic element selected from Ni, Ga, Fe, Mo, In, Nb, Nd, Co, Sm, Mg, Al, Ti, Cu, or Zn, Si, or P. The first region has a first crystal which has a layered rock salt structure, The second region has a second crystal which has a spinel-type structure. The ratio of the number of oxygen atoms to the sum of the number of manganese atoms and the element represented by M in the second region is smaller than the ratio of the number of oxygen atoms to the sum of the number of manganese atoms and the element represented by M in the first region. The graphene in question is a lithium-ion secondary battery, including multilayer graphene.

6. A lithium-ion secondary battery having a positive electrode, The positive electrode comprises a current collector and an active material layer on the current collector. The active material layer comprises a composite oxide containing lithium and manganese, and graphene covering at least a portion of the cleavage surface of the composite oxide. The composite oxide has a first region and a second region, The second region is located on the surface side of the first region and in the surface layer of the composite oxide, The first region and the second region each contain lithium and oxygen, The first region and the second region each contain manganese and an element represented by M, The element represented by M is a metallic element selected from Ni, Ga, Fe, Mo, In, Nb, Nd, Co, Sm, Mg, Al, Ti, Cu, or Zn, Si, or P. The first region has a first crystal which has a layered rock salt structure, The second region has a second crystal which has a spinel-type structure. The ratio of the number of oxygen atoms to the sum of the number of manganese atoms and the element represented by M in the second region is smaller than the ratio of the number of oxygen atoms to the sum of the number of manganese atoms and the element represented by M in the first region. The graphene in question is a lithium-ion secondary battery, including multilayer graphene.

7. In any one of claims 1 to 6, A lithium-ion secondary battery wherein the graphene contains oxygen, and the proportion of oxygen contained in the graphene is 2 atomic% or more and 20 atomic% or less.

8. In any one of claims 1 to 7, A lithium-ion secondary battery in which the thickness of the second region is 0.1 nm or more and 30 nm or less.

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