Electrode and manufacturing method of the electrode

Abstract

To enhance of a capacity per weight of a power storage device, enhance of a capacity per weight of an electrode, enhance of a capacity per weight of a particle having a positive electrode active material, increase an amount of a lithium ion per weight of the particle having the positive electrode active material, and thus realize a high-energy density, in which a battery reaction is stably performed in a positive electrode at a higher potential.SOLUTION: By using a lithium manganese composite oxide containing lithium, manganese, an element expressed by M, and oxygen as an active material of a positive electrode of a secondary battery, it is coated with a graphene oxide to be feedback. The active material having the graphene oxide, a conductive assistant agent, and a binder is formed. After the active material layer is implanted into an alcohol, an electrode to which the graphene oxide is feed-backed by performing a heating processing.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] One aspect of the present invention relates to a semiconductor device, a display device, a light-emitting device, an imaging device, a power storage device, a memory device, a driving method thereof, or a manufacturing method thereof. In particular, one aspect of the present invention relates to the structure of a storage battery and a method for manufacturing the same. In particular, it relates to a positive electrode active material and a positive electrode active material layer of a lithium ion storage battery.

Background Art

[0002] In recent years, portable electronic devices such as smartphones and tablets have rapidly spread. In addition, due to the increasing interest in environmental problems, attention has been focused on hybrid cars and electric vehicles, and the importance of storage batteries has been increasing. Examples of storage batteries include nickel-metal hydride batteries, lead storage batteries, and lithium ion storage batteries. Among them, lithium ion storage batteries are being actively developed because they can achieve high capacity and miniaturization.

[0003] The basic configuration of a storage battery is one in which an electrolyte is interposed between a positive electrode and a negative electrode. Examples of objects having an electrolyte include solid electrolytes and electrolytic solutions. As the positive electrode and the negative electrode, a configuration having a current collector and an active material layer provided on the current collector is typical. In the case of a lithium ion storage battery, a material capable of occluding and releasing lithium ions is used as the active material of the positive electrode and the negative electrode. and the negative electrode.

[0004] In a lithium ion storage battery, as the positive electrode active material, for example, those shown in Patent Document 1 , lithium iron phosphate (LiFePO4), lithium manganese phosphate (LiMnPO4), lithium cobalt phosphate (LiCoPO4), lithium nickel phosphate (LiNiPO4 )such as a phosphate compound having an olivine structure containing lithium (Li) and iron (Fe), manganese (Mn), cobalt (Co) or nickel (Ni) are known.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] In order to improve the performance of a storage battery, development of a method for manufacturing an electrode capable of sufficiently securing the capacity has been required. In addition, development of storage batteries still has room for improvement in various aspects such as charge-discharge characteristics, cycle characteristics, reliability, safety, and cost.

[0007] One aspect of the present invention is to increase the capacity per volume and / or per weight of a storage device. This is one of the problems. One aspect of the present invention is to increase the capacity per volume and / or per weight of an electrode. This is one of the problems.

[0008] One aspect of the present invention is to increase the capacity per volume and / or per weight of particles having a positive electrode active material. This is one of the problems. One aspect of the present invention is to increase the amount of lithium ions per volume and / or per weight of particles having a positive electrode active material and to achieve a high energy density. This is one of the problems. This is one of the problems.

[0009] One aspect of the present invention is to stably perform a battery reaction at a higher potential in a positive electrode having a positive electrode active material. This is one of the problems.

[0010] One aspect of the present invention is to provide a power storage device with suppressed capacity degradation during charge and discharge cycles. This is one of the problems. One aspect of the present invention is to provide a positive electrode active material that can be manufactured at low cost. This is one of the problems.

[0011] It is desirable that the positive electrode active material of a lithium ion battery has high ionic conductivity and electric conductivity. Therefore, one aspect of the present invention is to provide a positive electrode active material having high ionic conductivity and / or electric conductivity as one of the problems. This is one of the problems.

[0012] One aspect of the present invention is to provide a method for manufacturing an electrode of a power storage device as one of the problems. One aspect of the present invention is to provide a method for manufacturing a positive electrode active material of a secondary battery as one of the problems. This is one of the problems.

[0013] One aspect of the present invention is to provide a novel substance, a novel positive electrode active material, or a novel positive electrode active material layer as one of the problems. One aspect of the present invention is to provide novel particles having a positive electrode active material as one of the problems. One aspect of the present invention is to provide a novel power storage device, a novel battery, or a novel lithium ion battery as one of the problems. This is one of the problems. This is one of the problems. This is one of the problems.

[0014] Note that the description of these problems does not prevent the existence of other problems. Note that one aspect of the present invention does not necessarily need to solve all of these problems. Note that it is possible to extract other problems from the descriptions in the specification, drawings, claims, etc. This is one of the problems. This is one of the problems.

Means for Solving the Problems

[0015] One aspect of the present invention is a method for manufacturing an electrode, comprising forming an active material layer on a current collector, impregnating the active material layer with alcohol, and then performing a heat treatment. The active material layer is an active material coated with a carbon-containing film. After that, it is heat-treated, which is a method for manufacturing an electrode. The active material layer is an active material coated with a carbon-containing film. Characterized by comprising a material particle, a conductive aid, graphene oxide, and a binder A method for manufacturing an electrode

[0016] In addition, one aspect of the present invention is a method for manufacturing an electrode, which includes forming an active material layer on a current collector and impregnating the active material layer with alcohol and then performing a heat treatment. The active material layer includes an active material particle coated with a carbon-containing film, a conductive aid, graphene oxide, and a binder, and the carbon-containing film has reduced graphene oxide. This is a method for manufacturing an electrode characterized by this

[0017] In addition, one aspect of the present invention is an electrode having an active material layer on a current collector. The active material layer includes an active material particle, a conductive aid, a first reduced graphene oxide, a second reduced graphene oxide, and a binder. The first reduced graphene oxide is in contact with a first region of the active material particle, the second reduced graphene oxide is in contact with a second region of the active material particle, and the second reduced graphene oxide has a region covering at least a part of the first reduced graphene oxide This is an electrode characterized by this In each of the above configurations, the active material particle is preferably a lithium manganese composite oxide represented by Li Mn M O

[0018] At this time, the element M is preferably selected from chromium, cobalt, aluminum, nickel, iron, magnesium, molybdenum, zinc, indium, gallium, copper, titanium, niobium, silicon, and phosphorus a Mn b M c O d In each of the above configurations, the alcohol is preferably methanol, ethanol, 1-propanol, 2- In each of the above configurations, the alcohol is preferably methanol, ethanol, 1-propanol, 2- propyl alcohol, etc This is preferably selected from the group consisting of methanol, ethanol, 1-propanol, 2-propanol, etc

[0019] propyl alcohol, etc It is preferably selected from propanol, 1-butanol, 2-butanol, isobutyl alcohol, and tert -butyl alcohol.

[0020] Also, one aspect of the present invention is a storage battery characterized by having the above electrode and a negative electrode. That's it.

[0021] Also, one aspect of the present invention is an electronic device characterized by having the above storage battery, a display panel, operation keys, a speaker, or a microphone.

Effects of the Invention

[0022] According to one aspect of the present invention, the capacity per unit volume or / and per unit weight of the power storage device can be increased. According to one aspect of the present invention, the capacity per unit volume or / and per unit weight of the electrode can be increased. According to one aspect of the present invention, the capacity per unit volume or / and per unit weight of the particles having the positive electrode active material can be increased. According to one aspect of the present invention, the amount of lithium ions per unit volume or / and per unit weight of the particles having the positive electrode active material can be increased, and a high energy density can be realized. According to one aspect of the present invention, in the positive electrode having the positive electrode active material, the battery reaction can be stably carried out at a higher potential.

[0023] According to one aspect of the present invention, a power storage device with suppressed capacity degradation during charge-discharge cycles can be provided. According to one aspect of the present invention, a positive electrode active material that can be manufactured at low cost can be provided. According to one aspect of the present invention, a power storage device with suppressed capacity degradation during charge-discharge cycles can be provided. According to one aspect of the present invention, a positive electrode active material that can be manufactured at low cost can be provided. According to one aspect of the present invention, a power storage device with suppressed capacity degradation during charge-discharge cycles can be provided. According to one aspect of the present invention, a positive electrode active material that can be manufactured at low cost can be provided. According to one aspect of the present invention, a power storage device with suppressed capacity degradation during charge-discharge cycles can be provided. According to one aspect of the present invention, a positive electrode active material that can be manufactured at low cost can be provided.

[0024] According to one aspect of the present invention, in the positive electrode having the positive electrode active material, the battery reaction can be stably carried out at a higher potential. According to one aspect of the present invention, in the positive electrode having the positive electrode active material, the battery reaction can be stably carried out at a higher potential.

[0025] According to one aspect of the present invention, a power storage device with suppressed capacity degradation during charge-discharge cycles can be provided. According to one aspect of the present invention, a positive electrode active material that can be manufactured at low cost can be provided. According to one aspect of the present invention, a power storage device with suppressed capacity degradation during charge-discharge cycles can be provided. According to one aspect of the present invention, a positive electrode active material that can be manufactured at low cost can be provided. According to one aspect of the present invention, a power storage device with suppressed capacity degradation during charge-discharge cycles can be provided. According to one aspect of the present invention, a positive electrode active material that can be manufactured at low cost can be provided.

[0026] According to one aspect of the present invention, a positive electrode active material having high ionic conductivity and / or electric conductivity is provided. This can be achieved.

[0027] According to one aspect of the present invention, a method for manufacturing an electrode of an electric storage device can be provided. According to one aspect of the present invention, a method for manufacturing a positive electrode active material of a secondary battery can be provided.

[0028] According to one aspect of the present invention, a novel substance, a novel positive electrode active material, or a novel positive electrode active material layer can be provided. According to one aspect of the present invention, novel particles having a positive electrode active material can be provided. According to one aspect of the present invention, a novel electric storage device, a novel battery, or a novel lithium-ion storage battery can be provided. It should be noted that the description of these effects does not prevent the existence of other effects. It should be noted that one aspect of the present invention does not necessarily have all of these effects. It should be noted that other effects can be extracted from the descriptions in the specification, drawings, claims, etc.

[0029]

Brief Description of the Drawings

[0030]

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Mode for Carrying Out the Invention

[0031] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the following description, and those skilled in the art can easily understand that its form and details can be variously changed. Also, the present invention is not construed as being limited to the description of the embodiments shown below. In describing the configuration of the invention with reference to the drawings, the same reference numerals are commonly used among different drawings. When referring to similar ones, the hatch patterns are the same, and there may be cases where no reference numerals are particularly assigned. In the drawings, the size, thickness of the film (layer), or region may be exaggerated for clarity. are the same, and there may be cases where no reference numerals are particularly assigned. are the same, and there may be cases where no reference numerals are particularly assigned.

[0032] In the drawings, the size, thickness of the film (layer), or region may be exaggerated for clarity. are exaggerated.

[0033] The ordinal numbers attached as the first and second are used for convenience and do not indicate the process order or the stacking order. Therefore, for example, "the first" can be appropriately replaced with "the second" or "the third" and so on for explanation. Also, the ordinal numbers described in this specification and the like and the ordinal numbers used to specify one aspect of the present invention may not match. and the ordinal numbers used to specify one aspect of the present invention may not match.

[0034] The active material refers only to the material related to the insertion and extraction of ions as carriers, but in this specification and the like it may include the layer covering the 'active material'.

[0035] (Embodiment 1) In this embodiment, "particles having a lithium manganese composite oxide" according to one aspect of the present invention will be described. Also, an active material layer having the particles and an electrode having the active material layer will be described. First, the "particles having a lithium manganese composite oxide" according to one aspect of the present invention will be described. Then, the active material layer having the particles and the electrode having the active material layer will be described.

[0036] The lithium manganese composite oxide according to one aspect of the present invention has a composition formula Li a Mn b M c O d and can be represented by Here, the element M is preferably a metal element selected from elements other than lithium and manganese, or silicon or phosphorus. Also, it is preferable to satisfy 0 ≦ a / (b + c) < 2, c > 0, and 0.26 ≦ (b + c) / d < 0.5. Note that the lithium manganese composite oxide refers to an oxide containing at least lithium and manganese, and may contain at least one element selected from the group consisting of chromium, cobalt, aluminum, nickel, iron, magnesium, molybdenum, zinc, indium, gallium, copper, titanium, niobium, silicon, and phosphorus. Also, the lithium manganese composite oxide preferably has a layered rock salt type crystal structure. Further, the lithium manganese composite oxide may have a layered rock salt type crystal structure and a spinel type crystal structure. Also, the lithium manganese composite oxide preferably has an average primary particle diameter of 5 nm or more and 50 μm or less, for example. When measuring the entire particles of the lithium manganese composite oxide, it is preferable to satisfy 0 < a / (b + c) < 2, c > 0, and 0.26 ≦ (b + c) / d < 0.5 during discharge. Note that in order to exhibit a high capacity, the crystal structure, crystal orientation, or oxygen content in the surface layer portion and the central portion is different. The lithium manganese composite oxide may have a layered rock salt type crystal structure and a spinel type crystal structure. Also, the lithium manganese composite oxide preferably has an average primary particle diameter of 5 nm or more and 50 μm or less, for example. Also, when measuring the entire particles of the lithium manganese composite oxide, it is preferable to satisfy 0 < a / (b + c) < 2, c > 0, and 0.26 ≦ (b + c) / d < 0.5 during discharge.

[0037] Also, when measuring the entire particles of the lithium manganese composite oxide, it is preferable to satisfy 0 < a / (b + c) < 2, c > 0, and 0.26 ≦ (b + c) / d < 0.5 during discharge. Note that in order to exhibit a high capacity, the crystal structure, crystal orientation, or oxygen It is preferable to use lithium manganese composite oxides with different contents. Such lithium manganese composite oxides are preferably prepared such that 1.6 ≦ a ≦ 1.848, 0.19 ≦ c / b

[0038] <Synthesis> Next, a method for producing "particles having a lithium manganese composite oxide" according to one aspect of the present invention will be described. In the present embodiment, first, a lithium manganese composite oxide is synthesized. Then a coating layer is formed on the lithium manganese composite oxide to obtain particles having a first region, a second region, and a third region.

[0039] As raw materials for the lithium manganese composite oxide, manganese compounds and lithium compounds can be used. Further, together with the raw materials of the manganese compound and the lithium compound, raw materials of compounds containing at least one element selected from the group consisting of chromium, cobalt, aluminum, nickel, iron, magnesium, molybdenum, zinc, indium gallium, copper, titanium, niobium, silicon, and phosphorus can be used. Examples of the manganese compound include manganese dioxide, trimanganese dioxide, heptamanganese trioxide, hydrated manganese oxide manganese carbonate, manganese nitrate, and the like. Examples of the lithium compound include lithium hydroxide, lithium carbonate, lithium nitrate, and the like.

[0040] In the present embodiment, MnCO3 is used as the manganese compound, Li2CO 3 is used as the lithium compound, and NiO is used as the starting material.

[0041] First, as shown in step S11 of FIG. 1, the starting materials are weighed.

[0042] For example, when using Li2CO3, MnCO3, and NiO as starting materials, if the weighing ratio (molar ratio) is set to Li2CO3:MnCO3:NiO = 1:0.7:0.3, then the final product, lithium manganese composite oxide, will be produced as Li2Mn Ni 0.7 Ni 0.3 O3. In this case, the atomic ratio of the lithium manganese composite oxide is Li:(M n+Ni)=2:1.

[0043] In this embodiment, the weighing ratio (molar ratio) of the starting materials is adjusted so that the atomic ratio of the lithium manganese composite oxide deviates from Li:(Mn+Ni)=2 :1.

[0044] In this embodiment, the starting materials are weighed so that the weighing ratio (molar ratio) is Li2CO3:MnCO3:Ni O = 0.84:0.8062:0.318.

[0045] Next, as shown in step S12 of FIG. 1, the starting materials (Li2CO3, MnCO3, and NiO) are mixed. There is no particular limitation on the method for mixing the starting materials, and known crushers and grinders can be used. For example, a ball mill, bead mill, jet mill, roller mill, etc. can be mentioned. Also, the crushing and grinding methods can be either dry or wet. There is no particular limitation on the solvent that can be used in the wet process. For example, water, alcohol, acetone, etc. can be used.

[0046] When mixing the starting materials, if it is carried out wet, as shown in step S13 of FIG. 1, heat treatment is performed to evaporate or vaporize the solvent contained in the mixed starting materials. The heat treatment may be performed at a temperature of 50° C. or higher and 150° C. or lower. The solvent contained in the mixed starting materials is evaporated to obtain a mixed material.

[0047] Next, as shown in step S14 of FIG. 1, the mixed raw material is placed in a crucible and heated to 800° C. or higher for 100 The firing process is carried out at 0°C or less. For example, the firing process time is set to 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 firing atmosphere is air. Alternatively, an atmosphere using oxygen gas may be used. A fired product (lithium manganese composite oxide) is formed.

[0048] As shown in FIG. 2(A), the lithium matrices are formed by sintering multiple primary particles synthesized by firing. The calcium carbonate complex oxide is in a state where multiple primary particles are sintered to form large secondary particles. Therefore, as shown in step S15 of FIG. 1, a lithium sintered material is prepared by sintering a plurality of primary particles. The manganese-manganese composite oxide is subjected to a crushing process, and the fired material is crushed into primary particles; or In this specification, the crushing process refers to a process in which the sintered material is crushed into powder similar to primary particles. The term "pulverization" refers to the process of further breaking down primary particles. As in the mixing method, a known crusher or pulverizer can be used. For example, a ball mill or A bead mill or the like can be used. The crushing and pulverizing method may be a dry method or A wet method may also be used. There is no particular limitation on the solvent that can be used in the wet method. For example, water, alcohol, etc. Coal, acetone, etc. can be used.

[0049] Here, the size of the particles after crushing and pulverization can be determined, for example, by measuring the specific surface area of ​​the particles. It can be evaluated by doing so. By increasing the specific surface area of the particles having the lithium manganese composite oxide, when manufacturing a storage battery using the particles having the lithium manganese composite oxide as a positive electrode, for example, the contact area between the particles and the electrolytic solution can be increased. By increasing the contact area with the electrolytic solution, the reaction rate of the storage battery can be increased, and for example, the output characteristics can be improved. It is preferable that the specific surface area of the particles having the lithium manganese composite oxide increases by performing a crushing treatment. When manufacturing a storage battery, for example, the contact area between the particles and the electrolytic solution can be increased. By increasing the contact area with the electrolytic solution, the reaction rate of the storage battery can be increased, and for example, the output characteristics can be improved.

[0050] It is preferable that the specific surface area of the particles increases by performing a crushing treatment. The specific surface area of the particles having the lithium manganese composite oxide is preferably, for example, 0.1 m / g or more. Also, 2 when the specific surface area of the particles becomes too large, in the electrode manufactured using the particles, the amount of binder may be insufficient with respect to the surface area, and the strength may decrease. Here, when the amount of binder is increased, the capacity of the electrode per unit weight and per unit volume may decrease. Therefore, the specific surface area of the particles having the lithium manganese composite oxide is preferably, for example, 1 m / g or more and 50 m / g or less, and more preferably 5 m / g or more and 30 m / g or less. 2 2 2 2

[0051] In the present embodiment, the crushing treatment of the lithium manganese composite oxide in which the primary particles are sintered is performed by a wet method using acetone with a bead mill.

[0052] When performing the crushing treatment, when performing it wet, a heat treatment for evaporating the solvent is performed after the crushing treatment. The heat treatment performed here may be performed in the same manner as in step S13. Then, by performing vacuum drying, powdery lithium manganese composite oxide is obtained.

[0053] Next, a heat treatment is performed. As shown in step S16 of FIG. 1, the crushed lithium manganese composite oxide is placed in a crucible, and the heat treatment is performed at a temperature of 300° C. or higher and 1000° C. or lower, preferably 600° C. or higher and 900° C. or lower. For example, the heating time is 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. Next, a heat treatment is carried out. As shown in step S16 of FIG. 1, the lithium manganese composite oxide after the crushing treatment is put into a crucible, and the heat treatment is carried out at 300 °C or higher and 1000 °C or lower, preferably 6 00 °C or higher and 900 °C or lower. For example, the heating time is 5 hours or more and 20 hours or less and 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.

[0054] Through the above steps, a lithium manganese composite oxide represented by the composition formula Li a Mn b M c O d can be formed. In this embodiment, by setting the weighing ratio (molar ratio) of the raw materials to Li 2CO3:MnCO3:NiO = 0.84:0.8062:0.318, a lithium manganese composite oxide represented by the composition formula Li 2CO3:MnCO3:NiO = 0.84:0.8062:0.318, a lithium manganese composite oxide represented by the composition formula Li Mn 1.68 Mn 0.8062 M 0.318 O3 can be formed. can be formed.

[0055] After the crushing treatment shown in step S15, the lithium manganese composite oxide may have its crystallinity disrupted due to the impact of the crushing treatment. In addition, oxygen deficiency may occur in the lithium manganese composite oxide. Therefore, it is preferable to perform a heat treatment again on the powdered lithium manganese composite oxide after vacuum drying. After the crushing treatment shown in step S15, the lithium manganese composite oxide may have its crystallinity disrupted due to the impact of the crushing treatment. In addition, oxygen deficiency may occur in the lithium manganese composite oxide. Therefore, it is preferable to perform a heat treatment again on the powdered lithium manganese composite oxide after vacuum drying. After the crushing treatment shown in step S15, the lithium manganese composite oxide may have its crystallinity disrupted due to the impact of the crushing treatment. In addition, oxygen deficiency may occur in the lithium manganese composite oxide. Therefore, it is preferable to perform a heat treatment again on the powdered lithium manganese composite oxide after vacuum drying. After the crushing treatment shown in step S15, the lithium manganese composite oxide may have its crystallinity disrupted due to the impact of the crushing treatment. In addition, oxygen deficiency may occur in the lithium manganese composite oxide. Therefore, it is preferable to perform a heat treatment again on the powdered lithium manganese composite oxide after vacuum drying.

[0056] By performing a heat treatment on the lithium manganese composite oxide after the crushing treatment, oxygen deficiency can be repaired and the crystallinity disorder during the crushing treatment can be restored. In addition, the powdered lithium manganese composite oxide after the heat treatment is performed again may be crushed again and the powdered lithium manganese composite oxide after the heat treatment is performed again may be crushed again In this case, the crushing process can be performed using the same method as step S15 in FIG. 1. .

[0057] The lithium manganese composite oxide shown in this embodiment is adjusted so that the atomic ratio Li:(Mn + Ni) deviates from 2:1. Therefore, compared with the case where a lithium manganese composite oxide with an atomic ratio of Li:(Mn + Ni) = 2 :1 is used for the electrode, the voltage increases and the discharge capacity also increases.

[0058] Through the above steps, a particulate lithium manganese composite oxide can be obtained. Here, the lithium manganese composite oxide preferably has a first region and a second region. The second region is in contact with at least a part of the surface of the first region and is located outside the first region. Here, "outside" indicates being closer to the surface of the particle.

[0059] The first region and the second region contain lithium and oxygen. Also, at least one of the first region and the second region contains manganese. Further, at least one of the first region and the second region contains element M. Here, element M is preferably a metal element other than lithium and manganese, or silicon or phosphorus, more preferably a metal element selected from Ni, Ga, Fe, Mo, In, N b, Nd, Co, Sm, Mg, Al, Ti, Cu, or Zn, S i, or P, and even more preferably nickel.

[0060] <Coating layer> Next, a coating layer is provided on the lithium manganese composite oxide obtained by the above steps. The coating layer Preferably has carbon. Since carbon has high conductivity, particles coated with carbon can be used for the electrodes of a battery, for example, to reduce the resistance of the electrodes. Also, the coating layer may have graphene oxide or reduced graphene oxide. Or the coating layer may have a metal compound. Here, examples of the metal include cobalt, aluminum, nickel, iron, manganese, titanium, zinc, lithium, etc. Examples of the metal compound include oxides and fluorides of these metals. In this embodiment, a layer containing carbon is provided as the coating layer. As the layer containing carbon, it is preferable to use a graphene compound. In particular, it is preferable to use graphene or reduced graphene oxide. Also, graphene or reduced graphene oxide may be a single layer or may be stacked in 2 or more layers and 100 or less layers. Graphene and reduced graphene oxide have excellent electrical properties of having high conductivity, and excellent physical properties of having high flexibility and mechanical strength.

[0061] Preferably has carbon. Since carbon has high conductivity, particles coated with carbon can be used for the electrodes of a battery, for example, to reduce the resistance of the electrodes. Also, the coating layer may have graphene oxide or reduced graphene oxide. Or the coating layer may have a metal compound. Here, examples of the metal include cobalt, aluminum, nickel, iron, manganese, titanium, zinc, lithium, etc. Examples of the metal compound include oxides and fluorides of these metals. In this embodiment, a layer containing carbon is provided as the coating layer. As the layer containing carbon, it is preferable to use a graphene compound. In particular, it is preferable to use graphene or reduced graphene oxide. Also, graphene or reduced graphene oxide may be a single layer or may be stacked in 2 or more layers and 100 or less layers. Graphene and reduced graphene oxide have excellent electrical properties of having high conductivity, and excellent physical properties of having high flexibility and mechanical strength.

[0062] In this embodiment, a layer containing carbon is provided as the coating layer. As the layer containing carbon, it is preferable to use a graphene compound. In particular, it is preferable to use graphene or reduced graphene oxide. Also, graphene or reduced graphene oxide may be a single layer or may be stacked in 2 or more layers and 100 or less layers. Graphene and reduced graphene oxide have excellent electrical properties of having high conductivity, and excellent physical properties of having high flexibility and mechanical strength. In this embodiment, a layer containing carbon is provided as the coating layer. As the layer containing carbon, it is preferable to use a graphene compound. In particular, it is preferable to use graphene or reduced graphene oxide. Also, graphene or reduced graphene oxide may be a single layer or may be stacked in 2 or more layers and 100 or less layers. Graphene and reduced graphene oxide have excellent electrical properties of having high conductivity, and excellent physical properties of having high flexibility and mechanical strength. Preferably has carbon. Since carbon has high conductivity, particles coated with carbon can be used for the electrodes of a battery, for example, to reduce the resistance of the electrodes. Also, the coating layer may have graphene oxide or reduced graphene oxide. Or the coating layer may have a metal compound. Here, examples of the metal include cobalt, aluminum, nickel, iron, manganese, titanium, zinc, lithium, etc. Examples of the metal compound include oxides and fluorides of these metals. In this embodiment, a layer containing carbon is provided as the coating layer. As the layer containing carbon, it is preferable to use a graphene compound. In particular, it is preferable to use graphene or reduced graphene oxide. Also, graphene or reduced graphene oxide may be a single layer or may be stacked in 2 or more layers and 100 or less layers. Graphene and reduced graphene oxide have excellent electrical properties of having high conductivity, and excellent physical properties of having high flexibility and mechanical strength. In this embodiment, a layer containing carbon is provided as the coating layer. As the layer containing carbon, it is preferable to use a graphene compound. In particular, it is preferable to use graphene or reduced graphene oxide. Also, graphene or reduced graphene oxide may be a single layer or may be stacked in 2 or more layers and 100 or less layers. Graphene and reduced graphene oxide have excellent electrical properties of having high conductivity, and excellent physical properties of having high flexibility and mechanical strength.

[0063] The thickness of the layer containing carbon is preferably 1 nm or more and 50 nm or less.

[0064] Hereinafter, the graphene compound, graphene, or graphene oxide will be described. Graphene is an arrangement of carbon atoms in a single atomic layer and has π bonds between carbon atoms. A compound having graphene as a basic skeleton is called a "graphene compound" (also referred to as "Graphene Compound"). Graphene is an arrangement of carbon atoms in a single atomic layer and has π bonds between carbon atoms.

[0065] A compound having graphene as a basic skeleton is called a "graphene compound" (also referred to as "Graphene Compound"). Hereinafter, the graphene compound, graphene, or graphene oxide will be described. Graphene is an arrangement of carbon atoms in a single atomic layer and has π bonds between carbon atoms. A compound having graphene as a basic skeleton is called a "graphene compound" (also referred to as "Graphene Compound").

[0066] The details of the graphene compound will be described below.

[0067] Among the graphene compounds, those in which two or more and 100 or fewer layers of graphene overlap may be referred to as multi-g raphene. Graphene and multi-graphene have, for example, a longitudinal length of 50 nm or more and 100 μm or less, or 800 nm or more and 50 μm or less.

[0068] The graphene compound may be, for example, a compound in which an atom other than carbon, or an atomic group having an atom other than carbon, is modified on graphene or multi-graphene. Further, a compound in which an atomic group mainly composed of carbon such as an alkyl group is modified on graphene or multi-graphene may be used. The atomic group may sometimes be referred to as a substituent, a functional group, or a characteristic group, etc.

[0069] Here, different atoms or atomic groups may be modified on the front and back surfaces of the graphene compound, respectively. Further, when the graphene compound has multi-layer graphene, different atoms or atomic groups may be modified on each layer.

[0070] As an example of the graphene modified with the above-described atomic group, graphene or multi-g raphene modified with oxygen may be used. Further, for example, graphene or multi-graphene modified with a functional group containing oxygen may be used. Here, examples of the functional group containing oxygen include a carbonyl group such as an epoxy group or a carboxyl group, or a hydroxyl group, etc. Graphene modified with oxygen may sometimes be referred to as oxidized graphene.

[0071] Oxidized graphene can be obtained by the Hummers method, the Modified Hummers method, or graphite It can be prepared using various synthesis methods such as oxidation of the class.

[0072] For example, the Hummers method is a technique for oxidizing graphite such as flaky graphite to form oxidized graphite. The formed oxidized graphite has functional groups such as carbonyl groups, carboxyl groups, and hydroxyl groups bonded due to oxidation here and there of the graphite, and the crystallinity of the graphite is impaired and the interlayer distance is increased. Therefore, by ultrasonic treatment or the like, the interlayer can be easily separated to obtain graphene oxide.

[0073] Also, a highly conductive graphene compound can be obtained by reducing graphene oxide. Also, when the graphene compound obtained by reducing graphene oxide is called reduced graphene oxide or "RGO (Reduced Graphene Oxide)". In reduced graphene oxide or RGO, the oxygen contained in graphene oxide may not be completely desorbed. Oxygen or an oxygen-containing atomic group may remain in the state of being bonded in reduced graphene oxide or RGO. For example, RGO may have carbonyl groups such as epoxy groups and carboxyl groups, or functional groups such as hydroxyl groups.

[0074] The graphene compound may be in the form of a single sheet with a plurality of graphene compounds partially overlapping. In some cases, such a graphene compound is called a graphene compound sheet. The graphene compound sheet has, for example, a region with a thickness of 0.33 nm or more and 50 μm or less, more preferably greater than 0.34 nm and 10 μm or less. The group is made up of an atom other than carbon, an atomic group having an atom other than carbon, or an alkyl group or other carbon-based group. The graphene compound sheet may be modified by adding an atomic group such as In each, different atoms or groups of atoms may be modified.

[0075] Graphene compounds are composed of not only six-membered rings made of carbon, but also five-membered rings made of carbon and In this case, in the vicinity of a multi-membered ring other than a six-membered ring, In some cases, regions through which lithium ions can pass may be generated.

[0076] Furthermore, for example, a plurality of graphene compounds may be gathered together to form a sheet shape.

[0077] The graphene compound has a planar shape, which allows for surface contact.

[0078] Also, graphene, multi-graphene, or reduced graphene oxide The compound has excellent electrical properties, including high conductivity, as well as high flexibility and high mechanical strength. Graphene compounds have excellent physical properties such as a planar shape. This allows for surface contact with low contact resistance. In some cases, the amount of the conductive material may be very high, and a small amount is enough to efficiently form a conductive path in the active material layer. Therefore, by using a conductive graphene compound as a conductive assistant, This is preferable because it is possible to increase the contact area between the substance and the conductive additive. This is preferable because it may be possible to reduce the resistance.

[0079] In addition, when using an active material with a small particle size, for example, an active material with an average particle size of 1 μm or less, The specific surface area of the active material is large, and more conductive paths connecting the active materials are required. In such a case, it is particularly preferable to use a graphene compound that can efficiently form conductive paths even in a small amount.

[0080] Some graphene compounds can be used as insulators. For example, a graphene compound sheet can be used as a sheet-like insulator. Here, for example, graphene oxide may have higher insulating properties compared to graphene. Also, a graphene compound modified with an atomic group may be able to enhance its insulating properties depending on the type of the modifying atomic group.

[0081] Here, the graphene compound according to one aspect of the present invention may have a graphene precursor. The graphene precursor may include, for example, the above-mentioned graphene oxide, graphite oxide, and the like.

[0082] Note that graphene having an alkali metal or graphene having an element other than carbon such as oxygen may be sometimes referred to as a graphene analog. The graphene compound according to one aspect of the present invention includes graphene analogs as well.

[0083] Further, the graphene compound according to one aspect of the present invention may have atoms, atomic groups, and their ions between its layers. For example, it may have a lithium compound or lithium ions between the layers of graphene. Note that when the graphene compound has atoms, atomic groups, and their ions between its layers, the physical properties of the graphene compound, such as electrical conductivity and ionic conductivity, may change. Also, for example, the interlayer distance may become larger compared to multi-graphene.

[0084] ​​​ Also, when the graphene compound is reduced graphene oxide, the interlayer distance between adjacent reduced graphene oxides is preferably 0.335 nm or more and 0.700 nm or less.

[0085] The interlayer distance of the reduced graphene oxide can be evaluated, for example, by observing the cross section of the reduced graphene oxide with a transmission electron microscope (TEM). Also, the interlayer distance of the reduced graphene oxide can be calculated using the interplanar spacing information in various orientations that can be measured by X-ray diffraction (XRD). ope). The graphene compound according to one aspect of the present invention uses reduced graphene oxide. However, with respect to the entire reduced graphene oxide, the oxygen concentration measured by XPS (X-ray photoelectron spectroscopy) is, for example, preferably 0.3 atomic% or more and 20 atomic% or less, more preferably 1 atomic% or more and 11 atomic% or less, and even more preferably 3 atomic% or more and 10 atomic% or less.

[0086]

[0087] Also, when the graphene compound is measured by XPS, by analyzing the spectrum of the binding energy corresponding to C1s of carbon by waveform separation, the ratio occupied by the peak suggesting sp can be estimated as the area ratio with respect to the entire spectrum of C1s. Here, 2 For the graphene compound according to one aspect of the present invention, the ratio of sp 2 is preferably 50% or more and 90% or less with respect to the entire spectrum of C1s. By increasing the ratio of sp 2 ​​​ For example, the conductivity of the graphene compound can be increased.

[0088] Note that the physical property values such as the interplanar spacing and oxygen concentration shown in the above description are merely examples, and the graphene compound according to one aspect of the present invention is not limited thereto. is not limited to this.

[0089] Next, a method for coating a layer containing carbon on the lithium manganese composite oxide will be described.

[0090] The length of one side of graphene oxide (also referred to as flake size) is 50 nm or more and 100 μm or less, preferably 800 nm or more and 50 μm or less. The larger the flake size, the easier it is to cover the surface of the lithium manganese composite oxide, which is preferable. The larger the flake size, the easier it is to cover the surface of the lithium manganese composite oxide, which is preferable. is preferable because it becomes easier to cover the surface of the lithium manganese composite oxide.

[0091] First, graphene oxide and water are put into a kneader to prepare a graphene oxide dispersion. At this time, the graphene oxide is preferably 0.5 wt% or more and 5 wt% or less. If it is less than 0.5 wt%, it becomes difficult to cover the surface of the lithium manganese composite oxide. Also, if it exceeds 5 wt%, the electrode volume increases and the electrode weight becomes heavy. At this time, the graphene oxide is preferably 0.5 wt% or more and 5 wt% or less. If it is less than 0.5 wt%, it becomes difficult to cover the surface of the lithium manganese composite oxide. Also, if it exceeds 5 wt%, the electrode volume increases and the electrode weight becomes heavy. %, it becomes difficult to cover the surface of the lithium manganese composite oxide. Also, if it exceeds 5 wt%, the electrode volume increases and the electrode weight becomes heavy.

[0092] Next, as shown in step S17 shown in FIG. 1, the lithium manganese composite oxide is put into the dispersion solution, mixed, and solid kneading is performed. Note that solid kneading refers to kneading due to high viscosity. By performing solid kneading, the aggregation of the powder of the lithium manganese composite oxide can be loosened, and graphene oxide and the lithium manganese composite oxide can be more uniformly dispersed. Next, as shown in step S17 shown in FIG. 1, the lithium manganese composite oxide is put into the dispersion solution, mixed, and solid kneading is performed. Note that solid kneading refers to kneading due to high viscosity. By performing solid kneading, the aggregation of the powder of the lithium manganese composite oxide can be loosened, and graphene oxide and the lithium manganese composite oxide can be more uniformly dispersed. By performing solid kneading, the aggregation of the powder of the lithium manganese composite oxide can be loosened, and graphene oxide and the lithium manganese composite oxide can be more uniformly dispersed. and the lithium manganese composite oxide can be more uniformly dispersed.

[0093] Next, the mixture of graphene oxide and the lithium manganese composite oxide is dried under reduced pressure in a Berger. After drying, the lithium manganese composite oxide coated with graphene oxide is obtained by crushing in a mortar.

[0094] Next, as shown in step S18 shown in FIG. 1, a reduction treatment is performed on the graphene oxide coated on the surface of the lithium manganese composite oxide. The reduction treatment of graphene oxide may be performed by heat treatment, or may be performed by reacting in a solvent using a reducing agent. In this embodiment, graphene oxide is reacted in a solvent using a reducing agent.

[0095] By reacting graphene oxide in a solvent using a reducing agent, the graphene oxide coated on the surface of the lithium manganese composite oxide is reduced, and reduced graphene oxide is formed. Note that not all of the oxygen contained in graphene oxide is desorbed, and some oxygen may remain in the reduced graphene oxide. When the reduced graphene oxide contains oxygen, the ratio of oxygen is 0.3 atomic% or more and 20 atomic% or less of the entire reduced graphene oxide when measured by XPS, preferably 3 atomic% or more and 15 at omic% or less. This reduction treatment with a reducing agent is preferably performed at a temperature of room temperature or higher and 150 ° C or lower, preferably room temperature or higher and 80 ° C or lower. During the reduction treatment, heating can be performed to promote the reduction reaction. The reduction treatment time is preferably 3 minutes or more and 10 hours or less. As the reducing agent, ascorbic acid, hydrazine, dimethylhydrazine, hydroquinone, sodium borohydride (NaBH4), lithium aluminum hydride (LiAlH4), N

[0096] ,N-diethylhydroxylamine or their derivatives can be used. For example ​​​​​​​​​ In addition, ascorbic acid and hydroquinone have a weaker reducing power compared to hydrazine and sodium borohydride, so they are highly safe and preferable in terms of being easily industrially applicable.

[0097] As the solvent of the reducing solution, a polar solvent can be used. The material is not limited as long as it can dissolve the reducing agent. For example, any one or a mixture of two or more of water, methanol, ethanol, acetone, tetrahydrofuran (THF), dimethylformamide (DMF), N-methyl-2-pyrrolidone (NMP), dimethyl sulfoxide (DMSO), ethylene glycol, diethylene glycol, and glycerin can be used.

[0098] As the reducing solution containing the reducing agent and the solvent, a solution obtained by mixing ethanol and ascorbic acid, or a solution obtained by mixing water, ascorbic acid, and lithium hydroxide can be used. In this embodiment, the case of using a reducing solution containing ascorbic acid, water, ethanol, and lithium hydroxide will be described.

[0099] By reacting graphene oxide coated with lithium manganese composite oxide in the reducing solution, protons are added to the graphene oxide by ascorbic acid. Then, by the desorption of H2O, the graphene oxide is reduced.

[0100] After the reduction treatment, the reducing solution is filtered. The substance obtained here is called Substance A. For filtration, suction filtration or the like can be used. Alternatively, Substance A and the liquid can be separated by using centrifugation.

[0101] Next, the obtained substance A is washed. The washing may be performed, for example, using the solvent mentioned as the solvent contained in the reducing solution. It may be the same solvent as the solvent contained in the reducing solution, or a different solvent may be used.

[0102] Next, as shown in step S19 shown in FIG. 1, heat treatment is performed. This heat treatment step is, for example, performed at a temperature of 50°C or higher and less than 500°C, more preferably 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 sufficiently evaporated or vaporized and removed. Also in this heat treatment step, the reduction of graphene oxide can be promoted. The heat treatment may be performed under reduced pressure (vacuum) or at atmospheric pressure, or may be performed in a reducing atmosphere. Also, as the atmosphere during heating, air may be used or nitrogen or other inert gases may be used.

[0103] Here, when substance A is particles, it is preferable that the particles form, for example, secondary particles.

[0104] Here, when substance A forms secondary particles, the average value of the particle size of the secondary particles is, for example, preferably 50 μm or less, more preferably 30 μm or less, and even 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. Or, when substance A forms secondary particles, it may refer to the particle size of the secondary particles. The particle size of the secondary particles can be calculated, for example, by observing the particles with a microscope in addition to the aforementioned particle size distribution meter. Also, the particle size may be calculated, for example, as the diameter in circular conversion from the area of its cross section.

[0105] Note that after washing substance A, a liquid in which substance A is dispersed in a solvent is prepared, and the solution is sprayed Drying may be performed by baking. By performing spray drying, Substance A may form, for example, secondary particles, and the particle size may change.

[0106] When spray drying is performed after washing Substance A, it is preferable to perform the heat treatment shown in Step S19 after the spray drying.

[0107] Through the above steps, graphene oxide is reduced, and reduced graphene oxide can be formed on the surface of the lithium manganese composite oxide.

[0108] As described above, it is not necessary to completely desorb all the oxygen contained in graphene oxide, and some oxygen may remain in the reduced graphene oxide.

[0109] By performing heat treatment after the reduction treatment, the electrical conductivity of the reduced graphene oxide obtained may be further increased as compared with before the heat treatment.

[0110] In addition, particles in which reduced graphene oxide is provided on at least a part of the surface of the lithium manganese composite oxide can be formed.

[0111] Reduced graphene oxide has excellent electrical properties of having high conductivity, and excellent physical properties of having high flexibility and high mechanical strength. Therefore, by using the electrode containing the particles in a battery, for example, the electrical conductivity of the electrode can be further increased.

[0112] Through the above steps, particles according to one embodiment of the present invention can be obtained. The particles according to one embodiment of the present invention have a lithium manganese composite oxide. Further, the particles of one embodiment of the present invention have a first ​​​​​​​​ Preferably, it has a first region to a third region.

[0113] When the second region has a layered region, for example, its thickness is preferably 0.1 nm or more and 30 n m or less, and more preferably 1 nm or more and 15 nm or less.

[0114] The first region and the second region contain lithium and oxygen. Further, at least one of the first region and the second region contains manganese. Also, at least one of the first region and the second region contains element M. Preferably, at least one of the first region and the second region contains both manganese and element M.

[0115] Preferably, the first region and the second region contain both manganese and element M.

[0116] The third region preferably includes the surface of particles having a lithium manganese composite oxide according to one aspect of the present invention.

[0117] When the third region has a layered region, for example, its thickness is preferably 0.1 nm or more and 30 n m or less, more preferably 1 nm or more and 20 nm or less, and even more preferably 2 n m or more and 10 nm or less.

[0118] Fig. 2(A) shows an example in which the particle has a region 151 as the first region, a region 152 as the second region, and a region 153 as the third region.

[0119] As shown in Fig. 2(A), the region 152 has a region that at least partially contacts the surface of the region 151. Also, the region 153 at least partially contacts the surface of the region 152.

[0120] ​​​​​Also, as shown in FIG. 2(B), the region 151 may have a region not covered by the region 152. Also, the region 152 may have a region not covered by the region 153. Also, for example the region 151 may have a region in contact with the region 153. Also, the region 151 may have a region not covered by either the region 152 or the region 153.

[0121] When a power storage device is manufactured using particles having a lithium manganese composite oxide according to one aspect of the present invention in the battery reaction, for example, charging or discharging, the third region is preferably more stable than the first region and the second region.

[0122] Here, the second region may have a crystal structure different from that of the first region. Or, the second region may have crystals oriented differently from those of the first region.

[0123] For example, it is preferable that the second region has a spinel-type structure and the first region has a layered rock salt-type structure in this case.

[0124] Or, for example, the first region and the second region have a layered rock salt-type structure, and the first surface of the crystal of the first region and the second surface of the crystal of the second region are preferably parallel.

[0125] Here, when the first surface is the {0 0 1} surface of the layered rock salt-type structure, the {0 0 1} surface of the layered rock salt-type structure is preferably parallel to at least one of the {1 0 0} surface, the {1 3 -1} surface or the {-1 3 1} surface of the crystal of the second region. Or when the first surface is the {1 0 0} surface of the layered rock salt-type structure, the {1 0 0 ​} plane is preferably parallel to at least one of the {0 0 1}, {1 3 -1}, or {-1 3 1} planes of the crystals in the second region. Or, when the first plane is the {1 3 -1} plane of the layered rock salt structure, the {1 3 -1} plane of the layered rock salt structure is preferably parallel to at least one of the {0 0 1}, {1 0 0}, or {- 1 3 1} planes of the crystals in the second region. Or, when the first plane is the {-1 3 1} plane of the layered rock salt structure, the {-1 3 1} plane of the layered rock salt structure is , and is preferably parallel to at least one of the {0 0 1}, {1 0 0}, or {1 3 -1} planes of the crystals in the second region.

[0126] Next, the crystal orientations of the crystals in the first region and the crystals in the second region will be described.

[0127] Here, three crystal orientations of <1 0 0>, <1 1 0>, and <-1 1 0> are grouped into the first group. Also, <0 0 1>, <0 1 1>, and <0 1 -1> are grouped into the second group . Also, <-3 2 3>, <3 1 6>, and <6 -1 3> are grouped into the third group . Also, <3 2 -3>, <3 -1 6>, and <6 1 3> are grouped into the fourth group.

[0128] The crystals in the first region have an orientation selected from one of the first to fourth groups. The crystals in the second region have an orientation selected from one of the three groups other than the group to which the orientation of the crystals in the first region belongs among the first to fourth groups.

[0129] ​​​​Further, the second region preferably has a composition different from that of the first region.

[0130] For example, when the first region has lithium, manganese, element M, and oxygen, and the second region has lithium, manganese, element M, and oxygen, and the atomic number ratios of lithium, manganese, element M, and oxygen in the first region are represented by a1:b1:c1:d1, and the atomic number ratios of lithium, manganese, element M, and oxygen in the second region are represented by a2:b2:c2:d2, it will be described. Here, d1÷(b1+c1) is preferably 2.2 or more, more preferably 2.3 or more, and even more preferably 2.35 or more and 3 or less. Also, d2÷(b 2+c2) is preferably less than 2.2, more preferably less than 2.1, and even more preferably 1.1 or more and 1.9 or less.

[0131] Also, the manganese in the second region may have a valence different from that of the manganese in the first region. Also, the element M in the second region may have a valence different from that of the element M in the first region.

[0132] Here, when there is a spatial distribution in the composition of each region and the valence of the element, for example, evaluate the composition and valence at a plurality of locations, calculate the average value, and use it as the composition and valence of the region.

[0133] Also, a transition layer may be provided between the second region and the first region. Here, the transition layer is, for example, a region where the composition changes continuously or stepwise. Or, the transition layer is a region where the crystal structure changes continuously or stepwise. Or, the transition layer is a region where the lattice constant of the crystal changes continuously or stepwise. ​​​

[0134] Alternatively, a mixed layer may be provided between the second region and the first region. Here, the mixed layer refers to a layer in which two or more crystals having different crystal orientations are mixed, for example. Alternatively, the mixed layer refers to a layer in which two or more crystals having different crystal structures are mixed, for example. Alternatively, the mixed layer refers to a layer in which two or more crystals having different compositions are mixed, for example.

[0135] Here, the first region preferably has a layered rock salt structure. Also, the second region preferably has at least one of a spinel structure or a layered rock salt structure .

[0136] Here, for example, when manufacturing a storage battery or the like using "particles having a lithium manganese composite oxide" according to one aspect of the present invention, the first region to the third region may be formed in each step until the storage battery is manufactured.

[0137] For example, the first region to the third region may be formed before manufacturing the electrode, for example, after synthesizing the particles . Alternatively, they may be formed during the process of forming the electrode. Also, for example, the thickness, composition, crystal structure, etc. of the first region to the third region formed after synthesizing the particles may change during the process of forming the electrode.

[0138] By performing a heat treatment after the reduction treatment, for example, in "particles having a lithium manganese composite oxide" according to one aspect of the present invention, the first region to the third region may be formed. The first region to the third region that "particles having a lithium manganese composite oxide" has may be formed before the heat treatment. Alternatively, they may be formed during the process of the heat treatment. Yes. Also, for example, before the formation of the coating layer, after the formation of the coating layer, and after the reduction treatment, the thickness, composition, crystal structure, etc. of the first region to the third region may change during the heat treatment process. That's okay.

[0139] In the production process of the lithium manganese composite oxide, the crushing treatment process of the sintered lithium manganese composite oxide shown in step S15, etc. is an important process that affects the characteristics of the battery. In the crushing treatment process, the sintered lithium manganese composite oxide of primary particles is subjected to shear (stress of grinding) to form powdered lithium manganese composite oxide. At this time, when the lithium manganese composite oxide has a layered rock salt-type crystal structure, on the plane parallel to the layer or the plane perpendicular to the layer, the primary particles may split and crack. What is split and cracked by the primary particles is referred to as particles having a cleavage plane or particles with an exposed cleavage plane in this specification, etc. Note that the cracked primary particles include those without a cleavage plane.

[0140] Thus, if the primary particles of the lithium manganese composite oxide as the active material split and crack, it will cause a decrease in the discharge capacity and cycle characteristics of the battery.

[0141] Even in such a case, it is preferable to provide a carbon-containing layer on the cleavage plane of the lithium manganese composite oxide. The carbon-containing layer may cover all of the cleavage plane or may cover the entire lithium manganese composite oxide having a cleavage plane. Here, the cleavage plane includes, for example, the plane exposed by cleavage.

[0142] In one aspect of the present invention, reduced graphene is formed so as to cover the lithium manganese composite oxide. The reduced graphene may be provided over the entire surface of the lithium manganese composite oxide or only on a part thereof. Further, in the particles, it is preferable that reduced graphene is formed so as to cover the exposed cleavage plane. Also, it is sufficient that at least a part of the cleavage plane of the lithium manganese composite oxide is covered with the reduced graphene. The reduced graphene may be provided over the entire surface of the lithium manganese composite oxide or only on a part thereof. Further, in the particles, it is preferable that reduced graphene is formed so as to cover the exposed cleavage plane. Also, it is sufficient that at least a part of the cleavage plane of the lithium manganese composite oxide is covered with the reduced graphene. The reduced graphene may be provided over the entire surface of the lithium manganese composite oxide or only on a part thereof. Further, in the particles, it is preferable that reduced graphene is formed so as to cover the exposed cleavage plane. Also, it is sufficient that at least a part of the cleavage plane of the lithium manganese composite oxide is covered with the reduced graphene. The reduced graphene may be provided over the entire surface of the lithium manganese composite oxide or only on a part thereof. Further, in the particles, it is preferable that reduced graphene is formed so as to cover the exposed cleavage plane. Also, it is sufficient that at least a part of the cleavage plane of the lithium manganese composite oxide is covered with the reduced graphene. The reduced graphene may be provided over the entire surface of the lithium manganese composite oxide or only on a part thereof. Further, in the particles, it is preferable that reduced graphene is formed so as to cover the exposed cleavage plane. Also, it is sufficient that at least a part of the cleavage plane of the lithium manganese composite oxide is covered with the reduced graphene.

[0143] The reduced graphene may have excellent physical properties such as high flexibility and mechanical strength. Therefore, by using an electrode containing an active material covered with reduced graphene on at least a part of the cleavage plane of the lithium manganese composite oxide in a battery, even if the lithium manganese composite oxide expands and contracts due to repeated charge and discharge, it is possible to suppress the further cleavage and cracking of the lithium manganese composite oxide due to volume change. As a result, it is possible to suppress a decrease in the voltage of the battery and a decrease in the discharge capacity. Also, the cycle characteristics of the battery associated with charge and discharge can be improved. The reduced graphene may have excellent physical properties such as high flexibility and mechanical strength. Therefore, by using an electrode containing an active material covered with reduced graphene on at least a part of the cleavage plane of the lithium manganese composite oxide in a battery, even if the lithium manganese composite oxide expands and contracts due to repeated charge and discharge, it is possible to suppress the further cleavage and cracking of the lithium manganese composite oxide due to volume change. As a result, it is possible to suppress a decrease in the voltage of the battery and a decrease in the discharge capacity. Also, the cycle characteristics of the battery associated with charge and discharge can be improved. The reduced graphene may have excellent physical properties such as high flexibility and mechanical strength. Therefore, by using an electrode containing an active material covered with reduced graphene on at least a part of the cleavage plane of the lithium manganese composite oxide in a battery, even if the lithium manganese composite oxide expands and contracts due to repeated charge and discharge, it is possible to suppress the further cleavage and cracking of the lithium manganese composite oxide due to volume change. As a result, it is possible to suppress a decrease in the voltage of the battery and a decrease in the discharge capacity. Also, the cycle characteristics of the battery associated with charge and discharge can be improved. The reduced graphene may have excellent physical properties such as high flexibility and mechanical strength. Therefore, by using an electrode containing an active material covered with reduced graphene on at least a part of the cleavage plane of the lithium manganese composite oxide in a battery, even if the lithium manganese composite oxide expands and contracts due to repeated charge and discharge, it is possible to suppress the further cleavage and cracking of the lithium manganese composite oxide due to volume change. As a result, it is possible to suppress a decrease in the voltage of the battery and a decrease in the discharge capacity. Also, the cycle characteristics of the battery associated with charge and discharge can be improved. The reduced graphene may have excellent physical properties such as high flexibility and mechanical strength. Therefore, by using an electrode containing an active material covered with reduced graphene on at least a part of the cleavage plane of the lithium manganese composite oxide in a battery, even if the lithium manganese composite oxide expands and contracts due to repeated charge and discharge, it is possible to suppress the further cleavage and cracking of the lithium manganese composite oxide due to volume change. As a result, it is possible to suppress a decrease in the voltage of the battery and a decrease in the discharge capacity. Also, the cycle characteristics of the battery associated with charge and discharge can be improved. The reduced graphene may have excellent physical properties such as high flexibility and mechanical strength. Therefore, by using an electrode containing an active material covered with reduced graphene on at least a part of the cleavage plane of the lithium manganese composite oxide in a battery, even if the lithium manganese composite oxide expands and contracts due to repeated charge and discharge, it is possible to suppress the further cleavage and cracking of the lithium manganese composite oxide due to volume change. As a result, it is possible to suppress a decrease in the voltage of the battery and a decrease in the discharge capacity. Also, the cycle characteristics of the battery associated with charge and discharge can be improved. The reduced graphene may have excellent physical properties such as high flexibility and mechanical strength. Therefore, by using an electrode containing an active material covered with reduced graphene on at least a part of the cleavage plane of the lithium manganese composite oxide in a battery, even if the lithium manganese composite oxide expands and contracts due to repeated charge and discharge, it is possible to suppress the further cleavage and cracking of the lithium manganese composite oxide due to volume change. As a result, it is possible to suppress a decrease in the voltage of the battery and a decrease in the discharge capacity. Also, the cycle characteristics of the battery associated with charge and discharge can be improved.

[0144] <Method for manufacturing an electrode> Next, a method for manufacturing an electrode according to one aspect of the present invention will be described with reference to FIG. 3.

[0145] First, as shown in step S101 of FIG. 3, an electrode binder paste is prepared. Hereinafter, an example of a method for preparing the electrode binder paste will be shown. The electrode binder paste can be prepared by, for example, mixing the above-described active material covered with reduced graphene, graphene, a binder, a conductive assistant, etc. and kneading them together with a solvent. The electrode binder paste is a slurry. First, as shown in step S101 of FIG. 3, an electrode binder paste is prepared. Hereinafter, an example of a method for preparing the electrode binder paste will be shown. The electrode binder paste can be prepared by, for example, mixing the above-described active material covered with reduced graphene, graphene, a binder, a conductive assistant, etc. and kneading them together with a solvent. The electrode binder paste is a slurry. First, as shown in step S101 of FIG. 3, an electrode binder paste is prepared. Hereinafter, an example of a method for preparing the electrode binder paste will be shown. The electrode binder paste can be prepared by, for example, mixing the above-described active material covered with reduced graphene, graphene, a binder, a conductive assistant, etc. and kneading them together with a solvent. The electrode binder paste is a slurry. First, as shown in step S101 of FIG. 3, an electrode binder paste is prepared. Hereinafter, an example of a method for preparing the electrode binder paste will be shown. The electrode binder paste can be prepared by, for example, mixing the above-described active material covered with reduced graphene, graphene, a binder, a conductive assistant, etc. and kneading them together with a solvent. The electrode binder paste is a slurry. It may be in a leaflike shape or a paste shape.

[0146] As an example, the case where the electrode is the positive electrode of a storage battery will be described. Here, as the active material, a lithium manganese composite oxide coated with reduced graphene is used. Also, acetylene black (AB) is used as the conductive aid, polyvinylidene fluoride ( PVdF) is used as the binder, NMP is used as the solvent, and an example of adding graphene oxide will be described.

[0147] First, graphene oxide is dispersed in the solvent. With respect to the total weight of the electrode mixture paste (the total weight of the active material, graphene oxide, conductive aid, and binder), if the weight of graphene oxide is less than 0. 2 wt%, the conductivity will decrease when the active material layer is formed. Also, if the weight of graphene oxide exceeds 16 wt%, although it depends on the particle size of the active material, the viscosity of the paste will increase. Also, during the drying process after applying the paste to the current collector, a countercurrent is generated in the paste by heating, and the light and thin graphene oxide moves or aggregates, which may cause the active material layer to crack or the active material layer to peel off from the current collector. Therefore, the weight of graphene oxide is preferably 0.2 wt% or more and 16 wt% or less with respect to the paste. Note that since graphene oxide is reduced by a subsequent heat treatment process and its weight is approximately halved, the weight ratio of the reduced graphene oxide in the active material layer is 0.1 wt% or more and 8 wt% or less. or the active material layer to peel off from the current collector. Therefore, the weight of graphene oxide is preferably 0.2 wt% or more and 16 wt% or less with respect to the paste. Note that since graphene oxide is reduced by a subsequent heat treatment process and its weight is approximately halved, the weight ratio of the reduced graphene oxide in the active material layer is 0.1 wt% or more and 8 wt% or less. or the active material layer to peel off from the current collector. Therefore, the weight of graphene oxide is preferably 0.2 wt% or more and 16 wt% or less with respect to the paste. Note that since graphene oxide is reduced by a subsequent heat treatment process and its weight is approximately halved, the weight ratio of the reduced graphene oxide in the active material layer is 0.1 wt% or more and 8 wt% or less. or the active material layer to peel off from the current collector. Therefore, the weight of graphene oxide is preferably 0.2 wt% or more and 16 wt% or less with respect to the paste. Note that since graphene oxide is reduced by a subsequent heat treatment process and its weight is approximately halved, the weight ratio of the reduced graphene oxide in the active material layer is 0.1 wt% or more and 8 wt% or less. or the active material layer to peel off from the current collector. Therefore, the weight of graphene oxide is preferably 0.2 wt% or more and 16 wt% or less with respect to the paste. Note that since graphene oxide is reduced by a subsequent heat treatment process and its weight is approximately halved, the weight ratio of the reduced graphene oxide in the active material layer is 0.1 wt% or more and 8 wt% or less. graphene oxide is reduced by a subsequent heat treatment process and its weight is approximately halved, the weight ratio of the reduced graphene oxide in the active material layer is 0.1 wt% or more and 8 wt% or less. As the solvent, a polar solvent can be used. For example, any one or a mixture of two or more of methanol, ethanol, acetone, THF, DMF, NMP, and DMSO is used.

[0148] As the solvent, a polar solvent can be used. For example, any one or a mixture of two or more of methanol, ethanol, acetone, THF, DMF, NMP, and DMSO is used. As the solvent, a polar solvent can be used. For example, any one or a mixture of two or more of methanol, ethanol, acetone, THF, DMF, NMP, and DMSO is used. It is possible. In particular, NMP can disperse graphene oxide well, so it is preferable. preferable.

[0149] Next, an active material and a conductive aid are added. As the active material, the above-described active material may be used. Here, as an example, a lithium manganese composite oxide according to one aspect of the present invention is used as the active material. used.

[0150] As the conductive aid, for example, a carbon material, a metal material, or a conductive ceramic material can be used. Also, a fibrous material may be used as the conductive aid. The content of the conductive aid relative to the total amount of the active material layer is preferably 1 wt% or more and 10 wt% or less, and more preferably 1 wt% or more and 5 wt% or less. % or less.

[0151] The conductive aid can form an electric conduction network in the electrode. By the conductive aid, the electric conduction path between the positive electrode active materials can be maintained. By adding the conductive aid to the active material layer, an active material layer having high electric conductivity can be realized.

[0152] Next, by kneading these mixtures, aggregation of graphene oxide and the active material can be loosened. Also, in a polar solvent, the oxygen of the functional group of graphene oxide is negatively charged, so it is difficult for different graphene oxides to aggregate. Also, graphene oxide has a strong interaction with the active material. Therefore, graphene oxide can be more uniformly dispersed in the active material layer.

[0153] Next, a binder is added to these mixtures. The amount of the binder may be set according to the amounts of graphene oxide and the active material, and is 1 wt% with respect to the total weight of the paste. ​​​​​​​​​​ It may be added in an amount of 5 wt% or less. When graphene oxide is uniformly dispersed in a state of surface contact with a plurality of active material particles, by adding a binder, the dispersed state can be maintained, and the active material and graphene oxide can be bound together. Depending on the ratio of the active material to graphene oxide, it may not be necessary to add a binder, but when a binder is added, the strength of the electrode can be improved. Next, a solvent is added to these mixtures until a predetermined viscosity is reached, and kneading is performed to prepare a paste. By preparing a paste in the above steps, a paste with a uniform kneaded state of graphene oxide, active material, conductive assistant, and binder can be prepared. Next, as shown in step S102 of FIG. 3, the electrode mixture paste is applied to one or both sides of the current collector. For example, coating methods such as roll coating method using an applicator roll, screen printing method, doctor blade method, spin coating method, bar coating method, etc. can be applied. Also, the thickness of the electrode mixture paste during coating may be adjusted according to the desired loading amount of the active material of the electrode. Here, an undercoat may be formed on the current collector. The undercoat refers to a coating layer for reducing contact resistance and improving the adhesion between the current collector and the active material layer. As the undercoat, for example, a carbon layer, a metal layer, a layer containing carbon and polymer, and a layer containing metal and polymer 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. Also, the adhesion between the current collector and the active material layer can be improved.

[0154] Next, as shown in step S102 of FIG. 3, the electrode mixture paste is applied to one or both sides of the current collector. For example, coating methods such as roll coating method using an applicator roll, screen printing method, doctor blade method, spin coating method, bar coating method, etc. can be applied. Also, the thickness of the electrode mixture paste during coating may be adjusted according to the desired loading amount of the active material of the electrode. Next, as shown in step S102 of FIG. 3, the electrode mixture paste is applied to one or both sides of the current collector. For example, coating methods such as roll coating method using an applicator roll, screen printing method, doctor blade method, spin coating method, bar coating method, etc. can be applied. Also, the thickness of the electrode mixture paste during coating may be adjusted according to the desired loading amount of the active material of the electrode. Next, as shown in step S102 of FIG. 3, the electrode mixture paste is applied to one or both sides of the current collector. For example, coating methods such as roll coating method using an applicator roll, screen printing method, doctor blade method, spin coating method, bar coating method, etc. can be applied. Also, the thickness of the electrode mixture paste during coating may be adjusted according to the desired loading amount of the active material of the electrode. Next, as shown in step S102 of FIG. 3, the electrode mixture paste is applied to one or both sides of the current collector. For example, coating methods such as roll coating method using an applicator roll, screen printing method, doctor blade method, spin coating method, bar coating method, etc. can be applied. Also, the thickness of the electrode mixture paste during coating may be adjusted according to the desired loading amount of the active material of the electrode.

[0155] Next, as shown in step S102 of FIG. 3, the electrode mixture paste is applied to one or both sides of the current collector. For example, coating methods such as roll coating method using an applicator roll, screen printing method, doctor blade method, spin coating method, bar coating method, etc. can be applied. Also, the thickness of the electrode mixture paste during coating may be adjusted according to the desired loading amount of the active material of the electrode. Next, as shown in step S102 of FIG. 3, the electrode mixture paste is applied to one or both sides of the current collector. For example, coating methods such as roll coating method using an applicator roll, screen printing method, doctor blade method, spin coating method, bar coating method, etc. can be applied. Also, the thickness of the electrode mixture paste during coating may be adjusted according to the desired loading amount of the active material of the electrode. Next, as shown in step S102 of FIG. 3, the electrode mixture paste is applied to one or both sides of the current collector. For example, coating methods such as roll coating method using an applicator roll, screen printing method, doctor blade method, spin coating method, bar coating method, etc. can be applied. Also, the thickness of the electrode mixture paste during coating may be adjusted according to the desired loading amount of the active material of the electrode. Next, as shown in step S102 of FIG. 3, the electrode mixture paste is applied to one or both sides of the current collector. For example, coating methods such as roll coating method using an applicator roll, screen printing method, doctor blade method, spin coating method, bar coating method, etc. can be applied. Also, the thickness of the electrode mixture paste during coating may be adjusted according to the desired loading amount of the active material of the electrode. Next, as shown in step S102 of FIG. 3, the electrode mixture paste is applied to one or both sides of the current collector. For example, coating methods such as roll coating method using an applicator roll, screen printing method, doctor blade method, spin coating method, bar coating method, etc. can be applied. Also, the thickness of the electrode mixture paste during coating may be adjusted according to the desired loading amount of the active material of the electrode.

[0156] Here, an undercoat may be formed on the current collector. The undercoat refers to a coating layer for reducing contact resistance and improving the adhesion between the current collector and the active material layer. As the undercoat, for example, a carbon layer, a metal layer, a layer containing carbon and polymer, and a layer containing metal and polymer 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. Also, the adhesion between the current collector and the active material layer can be improved. Here, an undercoat may be formed on the current collector. The undercoat refers to a coating layer for reducing contact resistance and improving the adhesion between the current collector and the active material layer. As the undercoat, for example, a carbon layer, a metal layer, a layer containing carbon and polymer, and a layer containing metal and polymer 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. Also, the adhesion between the current collector and the active material layer can be improved. Here, an undercoat may be formed on the current collector. The undercoat refers to a coating layer for reducing contact resistance and improving the adhesion between the current collector and the active material layer. As the undercoat, for example, a carbon layer, a metal layer, a layer containing carbon and polymer, and a layer containing metal and polymer 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. Also, the adhesion between the current collector and the active material layer can be improved. Here, an undercoat may be formed on the current collector. The undercoat refers to a coating layer for reducing contact resistance and improving the adhesion between the current collector and the active material layer. As the undercoat, for example, a carbon layer, a metal layer, a layer containing carbon and polymer, and a layer containing metal and polymer 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. Also, the adhesion between the current collector and the active material layer can be improved. Here, an undercoat may be formed on the current collector. The undercoat refers to a coating layer for reducing contact resistance and improving the adhesion between the current collector and the active material layer. As the undercoat, for example, a carbon layer, a metal layer, a layer containing carbon and polymer, and a layer containing metal and polymer 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. Also, the adhesion between the current collector and the active material layer can be improved. The adhesion with the active material layer can be enhanced. When graphene is used as a conductive auxiliary agent, it is preferable that the undercoat does not dissolve in the reducing solution in the reduction process of graphene oxide. When graphene is used as a conductive auxiliary agent, it is preferable that the undercoat does not dissolve in the reducing solution in the reduction process of graphene oxide. is preferred.

[0157] In addition, as the undercoat, for example, a dispersion aqueous solution of graphite, acetylene black, etc., or a mixture obtained by mixing a polymer into the aqueous solution can be used. For example, a mixture of graphite and sodium polyacrylate (PAA), or a mixture of AB and PVdF can be used. In addition, as the undercoat, for example, a dispersion aqueous solution of graphite, acetylene black, etc., or a mixture obtained by mixing a polymer into the aqueous solution can be used. For example, a mixture of graphite and sodium polyacrylate (PAA), or a mixture of AB and PVdF can be used. can be used. Also, the weight ratio of graphite to PAA is in the range of graphite:PAA = 95:5 to 50:50, and the weight ratio of AB to PVdF is in the range of AB:PVdF = 70:30 to 50:50. can be used. Also, the weight ratio of graphite to PAA is in the range of graphite:PAA = 95:5 to 50:50, and the weight ratio of AB to PVdF is in the range of AB:PVdF = 70:30 to 50:50. 0, and the weight ratio of AB to PVdF is in the range of AB:PVdF = 70:30 to 50:50. range is sufficient.

[0158] In addition, if there are no problems with the adhesion between the active material layer and the current collector, the electrode strength, and the contact resistance, the undercoat does not necessarily need to be formed on the current collector. In addition, if there are no problems with the adhesion between the active material layer and the current collector, the electrode strength, and the contact resistance, the undercoat does not necessarily need to be formed on the current collector.

[0159] Next, as step S103, the solvent contained in the electrode mixture paste provided on the current collector is removed by vaporizing it by a method such as ventilation drying or reduced pressure (vacuum) drying to form an active material layer. Next, as step S103, the solvent contained in the electrode mixture paste provided on the current collector is removed by vaporizing it by a method such as ventilation drying or reduced pressure (vacuum) drying to form an active material layer. For example, it may be performed using hot air at 50°C or higher and 180°C or lower. The atmosphere is not particularly limited. is not particularly limited.

[0160] Here, the density of the active material layer may be increased by applying pressure to this active material layer by a compression method such as a roll press method or a flat press method. Also, when pressing, heat of 90°C or higher and 180°C or lower, preferably 120°C or lower, is applied to soften the binder (for example, PVdF) contained in the undercoat and the active material layer to such an extent that the characteristics of the electrode are not changed. Here, the density of the active material layer may be increased by applying pressure to this active material layer by a compression method such as a roll press method or a flat press method. Also, when pressing, heat of 90°C or higher and 180°C or lower, preferably 120°C or lower, is applied to soften the binder (for example, PVdF) contained in the undercoat and the active material layer to such an extent that the characteristics of the electrode are not changed. Here, the density of the active material layer may be increased by applying pressure to this active material layer by a compression method such as a roll press method or a flat press method. Also, when pressing, heat of 90°C or higher and 180°C or lower, preferably 120°C or lower, is applied to soften the binder (for example, PVdF) contained in the undercoat and the active material layer to such an extent that the characteristics of the electrode are not changed. is softened to such an extent that the characteristics of the electrode are not changed. This can further improve the adhesion between the current collector and the active material layer.

[0161] Next, in step S104, the active material layer is impregnated with alcohol. The method of applying the active material layer may be to immerse the current collector together with the active material layer in the liquid, or to spray the active material on the collector with an alkali solution. The temperature of the liquid may be between the melting point and the boiling point of the alcohol. The temperature is preferably between 40°C and 70°C, and more preferably between 40°C and 70°C. The impregnation time is 1 minute or more. Two hours or less is preferable, and from 30 minutes to one hour is more preferable.

[0162] Examples of alcohol include methanol, ethanol, 1-propanol, and 2-propanol. alcohol, 1-butanol, 2-butanol, isobutyl alcohol, or tert-butyl alcohol Alcohol with a low boiling point is easy to remove by evaporation. In addition, when a highly reducing alcohol is used, the reduction of graphene oxide is facilitated. Therefore, it is preferable to use ethanol, 1-propanol, 1-butanol, etc. It is more preferable to use

[0163] The liquid for impregnating the active material layer is a mixture of alcohol, water, or a stabilizer. A mixture of two or more alcohols may also be used. It may also be a mixed liquid with an organic solvent other than the above.

[0164] In this step, the active material layer is immersed in a solution containing a reducing agent (also called a reducing solution). In this manner, graphene oxide can be reduced.

[0165] However, when graphene oxide is reduced using a reducing solution, unexpected damage to the active material layer may occur. There is a possibility of damage. For example, the reducing agent may react with materials other than graphene oxide contained in the active material layer. In addition, the compound generated by the reduction of the solvent by the reducing agent may react with the materials contained in the active material layer.

[0166] Also, when using a reducing solution, depending on the nature of the reducing agent, the solution may become acidic or basic. Therefore, it is necessary to add a pH adjuster to adjust the pH of the solution, but the process becomes complicated. In addition, it may be difficult to keep the pH of the solution constant. If the pH of the solution cannot be kept constant, the materials contained in the active material layer may be damaged. For example, if the reducing solution is acidic and the active material layer contains a material that is unstable to acids or easily reacts with acids, it is likely to be damaged. Also, for example, if the reducing solution is basic and the active material layer contains a material that is unstable to bases or easily reacts with bases, it is likely to be damaged. In addition, by using a strong reducing agent as described above, unexpected reactions or damage may occur in the active material layer. Incidentally, examples of the active material that is unstable to acids include positive electrode active materials. Also, examples of the binder that easily reacts with bases include PVdF and the like.

[0167] Furthermore, when the active material layer is immersed in the reducing solution, the binder contained in the active material layer absorbs the solvent and swells or deforms. When the solvent of the reducing solution is water, since the molecules are small, it is easily absorbed by the binder. Also, when the solvent is an aprotic polar solvent such as NMP, it has a high affinity with binders such as PVdF and is easily absorbed by the binder. Therefore, the solvent of the reducing solution is water or NMP. When it is, for example, the phenomenon that the binder expands or deforms becomes remarkable. When the binder expands or deforms the network structure of the binder that binds the active material and graphene oxide in the active material layer may be cut or broken. Also, as the binder expands or deforms at this time, the active material layer may expand. In a state where the active material layer has expanded, reducing graphene oxide and constructing a three-dimensional network of electrical conduction in the active material layer may become difficult in some cases. Or, in a state where the active material layer has swollen, reducing graphene oxide and constructing a three-dimensional network of electrical conduction in the active material layer even if it is constructed, in the process of subsequently evaporating the solvent, since the active material layer shrinks, the network structure of electrical conduction may be damaged.

[0168] Due to the factors described above, when the damaged active material layer is immersed in an electrolyte or the like, the active material layer expands or deforms, so the network of electrical conduction formed in the active material layer is cut and becomes less.

[0169] Therefore, in one aspect of the present invention, after immersing the active material layer in alcohol in step S104 graphene oxide is reduced by heating in step S105 described later. Therefore there is no need to immerse the active material layer in a reducing solution. Alcohol is a substance that is easily reduced, and for graphene oxide, its reduction can be promoted, but for materials used for active materials, binders, etc. it is difficult to function to promote reduction, cause a reaction, etc. Therefore, the active material layer is less likely to be damaged. Also, since alcohol is neutral, even when the active material layer contains a material unstable to an acid or a base or a material likely to react with an acid or a base, the active material The layer is resistant to damage from acids and bases. It can also be used for alcohol, with pH adjustments. Since this is not necessary, step S104 can be said to be simple.

[0170] In addition, the binder does not easily absorb alcohol, or does not easily swell even if it absorbs alcohol. Therefore, it is possible to prevent the binder from absorbing the solvent and expanding. Before graphene is reduced, the network structure built by the binder is cut or destroyed. In addition, the active material layer can be prevented from expanding or shrinking. This allows the three-dimensional electrical conduction network constructed by graphene to be utilized. This can prevent the material layer from being destroyed due to expansion or contraction.

[0171] Next, in step S105, the active material layer is impregnated with the active material in step S104 by heat treatment. The excess alcohol is removed by heating under reduced pressure (vacuum) or in a reducing atmosphere. This heat treatment is preferably carried out at a temperature of 50° C. or higher and 300° C. or lower for 1 hour. The heat treatment is preferably performed for at least 48 hours. It evaporates or vaporizes water easily.

[0172] In addition, the graphene oxide is reduced by the heat treatment. The current collector may be heated. In this step, the remaining alcohol is converted to an acid by heating. To promote the reduction of graphene oxide, the reaction efficiency of the graphene oxide reduction reaction is increased. This makes it possible to fabricate an electrode with low internal resistance.

[0173] As described in this embodiment, according to one embodiment of the present invention, the active material layer is immersed in a reducing solution. Even without performing the process, graphene oxide can be reduced. That is, graphene oxide can be reduced under mild reaction conditions. Therefore, damage to the active material layer due to the reduction reaction can be reduced. As a result, an electrode that is less likely to have its electrical conduction path cut even when immersed in an electrolyte can be fabricated. Also, since alcohol promotes the reduction of graphene oxide by heating, the reaction efficiency of the reaction for reducing graphene oxide by heating can be increased. Thereby, an electrode with a small internal resistance can be manufactured. Therefore, by fabricating a storage battery using the method for manufacturing an electrode described in this embodiment, the cycle characteristics of the storage battery can be improved. Also, the rate characteristics of the storage battery can be improved.

[0174] Also, in one aspect of the present invention, a layered rock salt-type crystal structure active material used in this embodiment, such as a lithium manganese composite oxide having a cleavage property, is covered with graphene as described above, thereby suppressing cleavage due to pressure. However, in the electrode manufacturing process (for example, steps S101 or S102, etc.), when pressure is applied to the electrode mixture paste or the electrode to form it, pressure may be applied to the active material or the active material layer, causing the active material to further crack. Also, when pressure is applied to the active material, the reduced graphene oxide covering the surface of the active material when the active material particles are fabricated may be peeled off from the surface of the active material.

[0175] In this way, the primary particles of the active material split and crack, and the surface of the active material is covered. ​​​​​​​​​​​​​​​The peeling of graphene causes a decrease in the discharge capacity of the battery and a deterioration of the cycle characteristics. This becomes

[0176] In this embodiment, in step S101, when preparing the electrode binder paste, by adding oxidized graphene, the surface of the active material not covered by the reduced oxidized graphene formed in the step of FIG. 1 (for example, the surface where the active material is cracked or the surface where the reduced oxidized graphene on the surface of the active material is peeled off) can be covered with oxidized graphene. Further, in step S105, by reducing the oxidized graphene, the surface of the active material can be covered with the newly formed reduced oxidized graphene. In this way, the coverage rate of the reduced oxidized graphene on the surface of the active material can be increased. Thereby, a decrease in the voltage of the battery and a decrease in the discharge capacity can be suppressed. In addition, the cycle characteristics of the battery accompanying charge and discharge can be improved. Note that in this embodiment, the reduced oxidized graphene covering the active material may be a single layer or reduced oxidized graphene overlapping in 2 or more layers and 100 or less layers. Further, at least a part of the reduced oxidized graphene formed by step S105 only needs to be in contact with and cover the surface of the active material, and the reduced oxidized graphene may have a region overlapping with the reduced oxidized graphene formed in the step of FIG. 1. oxidized graphene may be a single layer or reduced oxidized graphene overlapping in 2 or more layers and 100 or less layers. Further, at least a part of the reduced oxidized graphene formed by step S105 only needs to be in contact with and cover the surface of the active material, and the reduced oxidized graphene may have a region overlapping with the reduced oxidized graphene formed in the step of FIG. 1.

[0177] Reduced oxidized graphene may have excellent electrical characteristics such as high conductivity, and excellent physical characteristics such as high flexibility and high mechanical strength. Therefore, by using the electrode in a battery, when the battery repeatedly charges and discharges, lithium manganese composite oxide ​​​​​​​​​​​Even if the object expands and contracts, it is possible to prevent the lithium manganese composite oxide from further splitting and cracking due to volume change. It can be prevented from cracking.

[0178] In addition, the pressure applied to the active material can be relaxed by the mechanical strength of the reduced graphene oxide. Thereby, for example, it is possible to suppress the further splitting and cracking of the lithium manganese composite oxide having cleavage properties. It can be suppressed from cracking.

[0179] Furthermore, for example, in a wound-type battery, when a large stress acts during winding of the electrode, or when the wound body of the electrode is housed in a casing, even if a stress always acts on the electrode toward the outside of the winding axis, it is possible to suppress the further splitting and cracking of the lithium manganese composite oxide. Even if stress is applied, it can be suppressed that the lithium manganese composite oxide further splits and cracks. It can be suppressed from cracking. It can be done.

[0180] Here, for example, when an electrode is manufactured using "particles having a lithium manganese composite oxide" according to one aspect of the present invention as an active material, and a storage battery is manufactured using the electrode, the first region to the third region of the "particles having a lithium manganese composite oxide" may be formed in any process of the manufacturing process of the "particles having a lithium manganese composite oxide" and the storage battery manufacturing process. When manufacturing an electrode using it as an active material and manufacturing a storage battery using the electrode, the first region to the third region of the "particles having a lithium manganese composite oxide" may be formed in any process of the manufacturing process of the "particles having a lithium manganese composite oxide" and the storage battery manufacturing process. The first region to the third region of the "particles having a lithium manganese composite oxide" may be formed in any process of the manufacturing process of the "particles having a lithium manganese composite oxide" and the storage battery manufacturing process. It may be formed in any process of the manufacturing process of the "particles having a lithium manganese composite oxide" and the storage battery manufacturing process. It may be formed.

[0181] In addition, the first region to the third region of the "particles having a lithium manganese composite oxide" may be formed before manufacturing the electrode, for example, after synthesizing the particles. Alternatively, it may be formed during the process of forming the electrode. Further, for example, the thickness, composition, crystal structure, etc. of the first region to the third region formed after synthesizing the particles may change during the process of forming the electrode. The first region to the third region of the "particles having a lithium manganese composite oxide" may be formed before manufacturing the electrode, for example, after synthesizing the particles. Alternatively, it may be formed during the process of forming the electrode. Further, for example, the thickness, composition, crystal structure, etc. of the first region to the third region formed after synthesizing the particles may change during the process of forming the electrode. It may be formed during the process of forming the electrode. Further, for example, the thickness, composition, crystal structure, etc. of the first region to the third region formed after synthesizing the particles may change during the process of forming the electrode. The thickness, composition, crystal structure, etc. of the first region to the third region may change during the process of forming the electrode. In addition, the first region to the third region may change in shape during the heat treatment in each process of manufacturing a storage battery or the like. It may be formed.

[0182] Further, in the electrode formation process, by performing heat treatment, for example, the elements contained in the binder and the particles having the lithium manganese composite oxide may react. As an example to explain the case where PVdF is used as the binder. PVdF is a polymer compound having fluorine atoms. By using a polymer compound having fluorine atoms as the binder, the elements contained in other materials constituting the electrode, such as the active material, the conductive assistant, the current collector, etc., and fluorine may form a bond. Here, having a bond means, for example, a bonding state that can be observed by analysis using XPS or the like. Or, having a bond means, for example, having a material having the bond. Further, as a material having such a bond, for example, metal fluorides and the like can be mentioned. As the metal fluoride, for example, lithium, manganese, and element M which are metals contained in the lithium manganese composite oxide according to one aspect of the present invention may form metal fluorides. Or, it may form a bond with the metal used for the current collector.

[0183] The elements contained in the coating layer of the lithium manganese composite oxide and fluorine may form a bond. For example, when a layer containing carbon is used as the coating layer, a compound containing fluorine and carbon may be formed. Here, the coating layer may coincide with the third region of the "particles having a lithium manganese composite oxide", or may have the third region and a part of the lithium manganese composite oxide. Further, the second region of the "particles having a lithium manganese composite oxide" may have, for example, a part of the coating layer.

[0184] ​​​ By forming such a bond, there are cases where, for example, the strength of the electrode can be increased further. Or, by forming a bond in advance, there are cases where, for example, irreversible reactions after manufacturing a storage battery can be suppressed.

[0185] The temperature of the heat treatment preferably for forming the bond is, for example, 120 °C or higher, more preferably 160 °C or higher, still more preferably 200 °C or higher, and even more preferably 250 °C or higher.

[0186] In addition, as the atmosphere for the heat treatment, gases such as oxygen, air, nitrogen, and rare gases can be used. Also, the heat treatment may be performed under atmospheric pressure or under reduced pressure. Here, for example, by using a gas having oxygen, the reaction between each material constituting the electrode, for example, particles having a lithium manganese composite oxide and a binder may be promoted. Here, the promotion of the reaction with the binder means that, for example, the elements contained in the binder and the elements contained in the particles having a lithium manganese composite oxide are observed by analysis such as XPS. Also, by using an inert gas such as nitrogen or a rare gas, the alteration of each material constituting the electrode, for example, the current collector, etc. may be suppressed in some cases. Also, by performing the heat treatment under reduced pressure, the alteration of each material constituting the electrode, for example, the current collector, etc. may be suppressed in some cases.

[0187] Here, when the heat treatment temperature is too high, decomposition etc. of each material constituting the electrode may occur. For example, particles having a lithium manganese composite oxide may undergo a decomposition reaction, and when used in a storage battery, its capacity may decrease. Therefore, the heat treatment temperature is 600 It is preferably below ℃, more preferably below 500℃, and even more preferably below 400℃.

[0188] Furthermore, the current collector on which the active material layer is formed may be pressed. Thereby, the adhesion between the active material layer and the current collector can be enhanced. Also, the density of the active material layer can be increased. Also, when pressing, heat of 90℃ or higher and 180℃ or lower, preferably 120℃ or lower is applied to soften the binder (for example, PVdF) contained in the undercoat and the active material layer to such an extent that the characteristics of the electrode are not changed, thereby further enhancing the adhesion between the current collector and the active material layer. can be further enhanced.

[0189] Finally, the electrode is manufactured by punching out the current collector and the active material layer to a predetermined size.

[0190] <Configuration of the electrode> Next, the electrode using the particles according to one aspect of the present invention will be described.

[0191] FIG. 4(A) is a top view of the electrode 100, and FIG. 4(B) is a cross-sectional view of the portion enclosed by the broken line in FIG. 4(A). The electrode 100 has a structure in which an active material layer 102 is provided on a current collector 101. In FIG. 4(A), an example is shown in which the active material layer 102 is provided on both sides of the current collector 101, but the active material layer 102 may be provided on only one side of the current collector 101.

[0192] The current collector 101 has no particular limitation as long as it exhibits high conductivity without causing a significant chemical change in the power storage device. For example, metals such as stainless steel, gold, platinum, zinc, iron, nickel, copper, aluminum, titanium, tantalum, manganese, and alloys thereof, sintered carbon, etc. Also, copper or stainless steel coated with carbon, nickel, titanium, etc. In addition, the heat resistance of silicon, neodymium, scandium, molybdenum, etc. can be improved. Aluminum alloys containing elements that react with silicon can be used. Alternatively, the insulating layer may be made of a metal element that reacts with silicon to form a silicide. The metallic elements that make up the alloy include zirconium, titanium, hafnium, vanadium, niobium, and tantalum. In addition, the current collector is made of The body 101 may be in the form of a foil, a plate (sheet), a net, a cylinder, a coil, a punched metal, or the like. Various shapes including expanded metal, porous and nonwoven fabric are used appropriately. Furthermore, in order to increase the adhesion with the active material layer, the current collector 101 has fine particles on its surface. The current collector 101 may have a thickness of 5 μm or more and 30 μm or less. It is a good idea to use the following.

[0193] The active material layer 102 includes an active material. The active material is a material that is involved in the insertion and desorption of ions, which serve as carriers. However, in this specification and the like, a layer containing an active material is called an active material layer. The material layer may contain a conductive assistant and a binder in addition to the active material.

[0194] When a negative electrode active material is used as the active material, for example, a carbon-based material, an alloy-based material, etc. is used. It is possible.

[0195] Carbon-based materials include graphite, graphitizable carbon (soft carbon), and non-graphitizable carbon (hard carbon). Examples of nanofibers include graphene, carbon nanotubes, graphene, and carbon black.

[0196] Graphite includes mesocarbon microbeads (MCMB), coke-based artificial graphite, and pitch. These include artificial graphite such as spheroidized artificial graphite, and natural graphite such as spheroidized natural graphite.

[0197] When lithium ions are inserted into graphite (when lithium-graphite intercalation compounds are formed), the potential is It has a low potential similar to that of lithium metal (0.1V to 0.3V vs. Li / Li + This allows lithium-ion batteries to exhibit high operating voltages. Graphite has a relatively high capacity per unit volume, small volume expansion, is inexpensive, and is a lithium It is preferable since it has advantages such as higher safety compared to metals.

[0198] An alloying material can be used as the negative electrode active material. There are also materials that can undergo charge and discharge reactions by providing an alloy with a metal that becomes a rear ion. For example, Ga, Si, Al, Ge, Sn, Pb, Sb, Bi, Ag A material containing at least one of Zn, Cd, In, etc. can be used. These elements have a larger capacity than carbon, and silicon in particular has a theoretical capacity of 4200mAh / g. Since the charge-discharge capacity of the battery is high, the capacity of the battery can be increased. Examples of such materials include Mg2Si, Mg2Ge, Mg2Sn, SnS2, V2Sn3, and FeS. n2, CoSn2, Ni3Sn2, Cu6Sn5, Ag3Sn, Ag3Sb, Ni2Mn Sb, CeSb3, LaSn3, La3Co2Sn7, CoSb3, InSb, SbSn etc.

[0199] In addition, the negative electrode active material is SiO, SnO, SnO2, titanium dioxide (TiO2), lithium Umm titanium oxide (Li4Ti5O 12 ), lithium-graphite intercalation compound (Li x C6), Oxides such as niobium pentoxide (Nb2O5), tungsten oxide (WO2), molybdenum oxide (MoO2 ) can be used.

[0200] Here, in order to increase the capacity of the power storage device, as the negative electrode active material, a material having silicon, For example, it is particularly preferable to use silicon, SiO, etc.

[0201] Also, as the negative electrode active material, a Li3N-type structure, which is a complex nitride of lithium and a transition metal, Li 3-x M x N (M = Co, Ni, Cu) can be used. For example, Li 2.6 Co 0.4 N3 shows a large charge-discharge capacity (900 mAh / g, 1890 mAh / cm 3 ) and is preferable. It is preferable.

[0202] When using a complex nitride of lithium and a transition metal, since the negative electrode active material contains lithium ions, It can be combined with materials such as V2O5 and Cr3O8 that do not contain lithium ions as the positive electrode active material It is preferable. Even when using a material containing lithium ions for the positive electrode active material , by previously desorbing the lithium ions contained in the positive electrode active material, A complex nitride of lithium and a transition metal can be used as the negative electrode active material.

[0203] Also, a material that causes a conversion reaction can be used as the negative electrode active material. For example , transition metal oxides such as cobalt oxide (CoO), nickel oxide (NiO), and iron oxide (FeO) that do not undergo an alloying reaction with lithium can be used as the negative electrode active material. Conversion reaction As materials in which stress occurs, further, oxides such as Fe2O3, CuO, Cu2O, RuO2, Cr2O 3, sulfides such as CoS 0.89 , NiS, CuS, nitrides such as Zn3N2, Cu3N, G e3N4, phosphides such as NiP2, FeP2, CoP3, fluorides such as FeF3, BiF3 also occur.

[0204] When a positive electrode active material is used as the active material, a material capable of inserting and desorbing lithium ions can be used as the positive electrode active material. For example, materials having an olivine-type structure, a layered rock salt-type structure , or a spinel-type structure, a NASICON-type crystal structure, etc. can be used .

[0205] In this embodiment, the case of using particles having a lithium manganese composite oxide as the positive electrode active material will be described, but other active materials may be included. Examples of other active materials include , compounds such as LiFeO2, LiCoO2, LiNiO2, LiMn2O4, V2O5, Cr2O 5, MnO2, etc. can be used as materials.

[0206] Or, a lithium-containing composite phosphate (general formula LiMPO4 (M is one or more of Fe(II), Mn( II), Co(II), Ni(II))) can be used. Representative examples of the general formula LiM PO4 include LiFePO4, LiNiPO4, LiCoPO4, LiMn PO4, LiFe a Ni b PO4, LiFe a Co b PO4, LiFe a Mn b PO4, LiNi a Co b PO4, LiNi a Mn bPO4 (where a + b ≤ 1, 0 < a < 1, 0 < b < 1), LiFe c Ni d Co e PO4, LiFe c Ni d Mn e PO4, LiNi c Co d Mn e PO4 (where c + d + e ≤ 1, 0 < c < 1, 0 < d < 1, 0 < e < 1), L iFe f Ni g Co h Mn i PO4 (where f + g + h + i ≤ 1, 0 < f < 1, 0 < g < 1 , 0 < h < 1, 0 < i < 1), etc. Lithium metal phosphate compounds are exemplified.

[0207] Or, a lithium - containing composite 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. As representative examples of the general formula Li MSiO4, there are Li (2-j) MSiO4, Li (2-j) FeS iO4, Li (2-j) NiSiO4, Li (2-j) CoSiO4, Li (2-j) M nSiO4, Li (2-j) Fe k Ni l SiO4, Li (2-j) Fe k Co l SiO 4, Li (2-j) Fe k Mn l SiO4, Li (2-j) Ni k Co l SiO4, Li (2-j) Ni k Mn l SiO4 (where k + l ≤ 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, L i (2-j) Ni m Co n Mn q SiO4 (m + n + q is 1 or less, 0 < m < 1, 0 < n < 1, 0 < q < 1), Li (2-j) Fe r Ni s Co t Mn u SiO4 (r + s + t + u is 1 or less, 0 < r < 1, 0 < s < 1, 0 < t < 1, 0 < u < 1), etc. lithium silicate compounds are exemplified.

[0208] 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 NAS ICON type compounds can be used. Examples of NASICON type compounds include Fe2(M nO4)3, Fe2(SO4)3, Li3Fe2(PO4)3, etc. Also, positive electrode active materials include compounds represented by the general formula Li2MPO4F, Li2MP2O7, Li5MO4 (M = Fe, Mn ), perovskite type fluorides such as FeF3, metal chalcogenides (sulfides, selenides, tellurides) such as TiS2, Mo S2, materials having an inverse spinel type crystal structure such as LiMVO4, vanadium oxide systems (V2O5, V6O ), manganese oxides, organic sulfur compounds, etc. can be used. 13 Li V3O8, etc.), manganese oxides, organic sulfur compounds, etc. can be used.

[0209] In addition, when the carrier ions are alkali metal ions or alkaline earth metal ions other than lithium ions, as the positive electrode active material, in the above lithium compound, lithium-containing composite phosphate, and lithium-containing composite silicate, a compound in which lithium is substituted with a carrier such as an alkali metal (e.g., sodium, potassium, etc.) or an alkaline earth metal (e.g., calcium, strontium, barium, beryllium, magnesium, etc.) may be used. In the case of ions, as the positive electrode active material, a compound in which lithium is substituted with a carrier such as an alkali metal (e.g., sodium, potassium, etc.) or an alkaline earth metal (e.g., calcium, strontium, barium, beryllium, magnesium, etc.) may be used in the above lithium compound, lithium-containing composite phosphate, and lithium-containing composite silicate. In the case of ions, as the positive electrode active material, a compound in which lithium is substituted with a carrier such as an alkali metal (e.g., sodium, potassium, etc.) or an alkaline earth metal (e.g., calcium, strontium, barium, beryllium, magnesium, etc.) may be used in the above lithium compound, lithium-containing composite phosphate, and lithium-containing composite silicate. In the case of ions, as the positive electrode active material, a compound in which lithium is substituted with a carrier such as an alkali metal (e.g., sodium, potassium, etc.) or an alkaline earth metal (e.g., calcium, strontium, barium, beryllium, magnesium, etc.) may be used in the above lithium compound, lithium-containing composite phosphate, and lithium-containing composite silicate. In the case of ions, as the positive electrode active material, a compound in which lithium is substituted with a carrier such as an alkali metal (e.g., sodium, potassium, etc.) or an alkaline earth metal (e.g., calcium, strontium, barium, beryllium, magnesium, etc.) may be used in the above lithium compound, lithium-containing composite phosphate, and lithium-containing composite silicate.

[0210] The average particle size of the positive electrode active material is preferably, for example, 5 nm or more and 50 μm or less.

[0211] The active material layer 102 may contain a conductive assistant. As the conductive assistant, any material that is an electronic conductor itself and does not cause a chemical change with other substances in the battery device may be used. For example, natural graphite, artificial graphite such as mesocarbon microbeads, carbon fibers, etc. can be used. As the conductive assistant, any material that is an electronic conductor itself and does not cause a chemical change with other substances in the battery device may be used. For example, natural graphite, artificial graphite such as mesocarbon microbeads, carbon fibers, etc. can be used. As the conductive assistant, any material that is an electronic conductor itself and does not cause a chemical change with other substances in the battery device may be used. For example, natural graphite, artificial graphite such as mesocarbon microbeads, carbon fibers, etc. can be used. As the carbon fiber, for example, carbon fibers such as mesophase pitch-based carbon fibers and isotropic pitch-based carbon fibers can be used. Also, as the carbon fiber, carbon nanofibers, carbon nanotubes, etc. can be used. As the carbon fiber, for example, carbon fibers such as mesophase pitch-based carbon fibers and isotropic pitch-based carbon fibers can be used. Also, as the carbon fiber, carbon nanofibers, carbon nanotubes, etc. can be used. As the carbon fiber, for example, carbon fibers such as mesophase pitch-based carbon fibers and isotropic pitch-based carbon fibers can be used. Also, as the carbon fiber, carbon nanofibers, carbon nanotubes, etc. can be used. As the carbon fiber, for example, carbon fibers such as mesophase pitch-based carbon fibers and isotropic pitch-based carbon fibers can be used. Also, as the carbon fiber, carbon nanofibers, carbon nanotubes, etc. can be used. As the conductive assistant, for example, carbon materials such as carbon black (acetylene black (AB), etc.), graphite (graphite) particles, fullerenes, graphene, etc. can be used. Also, for example, metal powders, metal fibers, conductive ceramic materials, etc. such as copper, nickel, aluminum, silver, gold, etc. can be used. As the conductive assistant, for example, carbon materials such as carbon black (acetylene black (AB), etc.), graphite (graphite) particles, fullerenes, graphene, etc. can be used. Also, for example, metal powders, metal fibers, conductive ceramic materials, etc. such as copper, nickel, aluminum, silver, gold, etc. can be used. As the conductive assistant, for example, carbon materials such as carbon black (acetylene black (AB), etc.), graphite (graphite) particles, fullerenes, graphene, etc. can be used. Also, for example, metal powders, metal fibers, conductive ceramic materials, etc. such as copper, nickel, aluminum, silver, gold, etc. can be used. In this embodiment, as an example, acetylene black (AB) is used as the conductive assistant. In this embodiment, as an example, acetylene black (AB) is used as the conductive assistant.

[0212] Sheet-like graphene has excellent electrical properties such as high conductivity, as well as excellent physical properties such as flexibility and mechanical strength. Therefore, by using graphene as a conductive aid, the electrical conductivity between active materials or between the active material and the current collector can be increased.

[0213] In addition, reduced graphene oxide obtained by reducing graphene oxide can be used as a conductive aid. For example, by heat-treating an active material layer in which graphene oxide is dispersed, the graphene oxide is reduced to form reduced graphene oxide. Since the reduced graphene oxide has a planar shape, it enables surface contact. It may also have excellent electrical properties such as high conductivity, as well as excellent physical properties such as flexibility and mechanical strength. Therefore, by using the reduced graphene oxide as a conductive aid, the electrical conductivity between active materials or between the active material and the current collector can be increased.

[0214] The active material layer 102 preferably has a binder, and the binder more preferably has a water-soluble polymer. Also, the active material layer 102 may have a plurality of types of binders.

[0215] Examples of the binder include PVdF, polystyrene, methyl polyacrylate, polymethyl methacrylate (PMMA), sodium polyacrylate, polyvinyl alcohol (PVA), polyethylene oxide (PEO), polypropylene oxide, polyimide, polyvinyl chloride, polytetrafluoroethylene, polyethylene, polypropylene, isobutylene, poly ethylene terephthalate, nylon, polyacrylonitrile (PAN), and other materials.​​ It is preferable to do so.

[0216] Also, as the binder, rubber materials such as styrene-butadiene rubber (SBR), styrene-isoprene- styrene rubber, acrylonitrile-butadiene rubber, butadiene rubber, ethylene-propylene- diene copolymer can be used. When these rubber materials are used in combination with a water-soluble polymer, it is more preferable. These rubber materials have rubber elasticity and are easy to stretch and contract. Therefore, they are strong against the expansion and contraction of the active material accompanying charge and discharge, and the stress accompanying bending of the electrode, etc., and a highly reliable electrode can be obtained. On the other hand, there are cases where they have a hydrophobic group and are insoluble in water. In such a case, since the particles are dispersed in a state of not dissolving in water in an aqueous solution, it may be difficult to increase the viscosity of the composition containing the solvent used for forming the active material layer 102 (also referred to as an electrode binder paste) to a viscosity suitable for coating. At this time, when a water-soluble polymer with a high viscosity adjusting function, such as a polysaccharide, is used, the effect of moderately increasing the viscosity of the solution can be expected, and a good electrode with high uniformity, for example, an electrode with high uniformity in electrode film thickness and electrode resistance, can be obtained by being uniformly dispersed with the rubber material. The binders may be used alone or in combination of two or more. One aspect of the present invention is not limited to these. For example, as one aspect of the present invention, an example when applied to a lithium-ion battery was shown, but one aspect of the present invention is not limited to this. One aspect of the present invention is applicable to various storage batteries, lead storage batteries, lithium-ion polymer storage batteries, nickel-

[0217] hydrogen storage batteries, nickel-cadmium storage batteries, nickel-iron storage batteries, nickel-zinc storage batteries.

[0218] One aspect of the present invention is not limited thereto. For example, as one aspect of the present invention, although an example when applied to a lithium-ion battery was shown, one aspect of the present invention is not limited to this. One aspect of the present invention is applicable to various storage batteries, lead storage batteries, lithium-ion polymer storage batteries, nickel- hydrogen storage batteries, nickel-cadmium storage batteries, nickel-iron storage batteries, nickel-zinc storage batteries, hydrogen storage batteries, nickel-cadmium storage batteries, nickel-iron storage batteries, nickel-zinc storage batteries​​ , silver oxide-zinc battery, solid-state battery, air battery, primary battery, capacitor, electric double layer capacitor, ultracapacitor, supercapacitor, or lithium-ion capacitor may be applied to any of them. In one aspect of the present invention, graphene or reduced graphene oxide is used as an electrode for a supercapacitor, which is a capacitor with a very large capacitance, an oxygen reduction electrode catalyst, a material for a dispersion liquid with lower friction than lubricating oil, a transparent electrode for a display device, a solar cell, etc., a gas barrier material, a polymer material with high mechanical strength and low weight, a material for a highly sensitive nanosensor for detecting uranium or plutonium contained in radioactive contaminated water, or a material for removing radioactive substances may also be used.

[0219] This embodiment can be implemented in appropriate combination with other embodiments.

[0220] (Embodiment 2) In this embodiment, an example of a power storage device using an electrode according to one aspect of the present invention is shown.

[0221] In this specification, etc., the power storage device refers to elements and devices having a power storage function in general. For example, it includes storage batteries such as lithium-ion secondary batteries, lithium-ion capacitors, and electric double layer capacitors.

[0222] <Thin-film battery> [Thin-film battery 1] Fig. 5 shows an example of a thin-film battery as a power storage device. If the thin-film battery has a flexible structure, it can be bent according to the deformation of the electronic device when mounted on an electronic device having at least a part of a flexible part.

[0223] Fig. 5 shows an external view of a thin battery 500. Figs. 6(A) and 6(B) show cross-sectional views between the dashed-dotted lines A1 - A2 and between B1 - B2 shown in Fig. 5. The thin battery 500 includes a positive electrode 503 having a positive electrode current collector 501 and a positive electrode active material layer 502, a negative electrode 506 having a negative electrode current collector 504 and a negative electrode active material layer 505, a separator 507, an electrolytic solution 508, and an exterior body 509. A separator 507 is installed between the positive electrode 5 03 and the negative electrode 506 provided in the region surrounded by the exterior body 509. Also, the region surrounded by the exterior body 509 is filled with the electrolytic solution 508. A separator 507 is installed between the positive electrode 503 and the negative electrode 506 provided in the region surrounded by the exterior body 509. Also, the region surrounded by the exterior body 509 is filled with the electrolytic solution 508. At least one of the positive electrode 503 and the negative electrode 506 uses the electrode according to one aspect of the present invention. Also, both the positive electrode 503 and the negative electrode 506 may use the electrode according to one aspect of the present invention.

[0224] First, the configuration of the positive electrode 503 will be described. It is preferable to use the electrode according to one aspect of the present invention for the positive electrode 503. Here, an example is shown in which the electrode 100 shown in Embodiment 1 is used for the positive electrode 503. As the solvent of the electrolytic solution 508, an aprotic organic solvent is preferable. For example, ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate, chloroethylene carbonate, vinylene carbonate (VC), γ-butyrolactone, γ-valerolactone, dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), methyl formate, methyl acetate, methyl butyrate, 1,3-dioxane, 1,4-dioxane, dimethoxyethane (DME), dimethyl sulfoxide, diethyl sulfoxide, etc. are used. It is also possible.

[0225] First, the configuration of the positive electrode 503 will be described. It is preferable to use the electrode according to one aspect of the present invention for the positive electrode 503. Here, an example is shown in which the electrode 100 shown in Embodiment 1 is used for the positive electrode 503. Here, an example is shown in which the electrode 100 shown in Embodiment 1 is used for the positive electrode 503. is shown.

[0226] As the solvent of the electrolytic solution 508, an aprotic organic solvent is preferable. For example, ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate, chloroethylene carbonate, vinylene carbonate (VC), γ-butyrolactone, γ-valerolactone, dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), methyl formate, methyl acetate, methyl butyrate, 1,3-dioxane, 1,4-dioxane, dimethoxyethane (DME), dimethyl sulfoxide, diethyl sulfoxide, etc. are used. carbonate (EC), propylene carbonate (PC), butylene carbonate, chloroethylene carbonate, vinylene carbonate (VC), γ-butyrolactone, γ-valerolactone, dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), methyl formate, methyl acetate, methyl butyrate, 1,3-dioxane, 1,4-dioxane, dimethoxyethane (DME), dimethyl sulfoxide, diethyl sulfoxide, etc. are used. carbonate, vinylidene carbonate (VC), γ-butyrolactone, γ-valerolactone, dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), methyl formate, methyl acetate, methyl butyrate, 1,3-dioxane, 1,4-dioxane, dimethoxyethane (DME), dimethyl sulfoxide, diethyl sulfoxide, etc. are used. lactone, dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), methyl formate, methyl acetate, methyl butyrate, 1,3-dioxane, 1,4-dioxane, dimethoxyethane (DME), dimethyl sulfoxide, diethyl sulfoxide, etc. are used. methyl carbonate (EMC), methyl formate, methyl acetate, methyl butyrate, 1,3-dioxane, 1,4-dioxane, dimethoxyethane (DME), dimethyl sulfoxide, diethyl sulfoxide, etc. are used. oxane, 1,4-dioxane, dimethoxyethane (DME), dimethyl sulfoxide, diethyl sulfoxide, etc. are used. Ethyl ether, methyl diglyme, acetonitrile, benzonitrile, tetrahydrofura n, sulfolane, sultone, etc., one kind, or any combination of two or more of these can be used in any ratio.

[0227] Also, by using a polymer material that gels as a solvent for the electrolytic solution, safety against leakage and the like is enhanced. Also, the battery can be made thinner and lighter. Representative examples of the polymer material that gels include silicone gel, acrylic gel, acrylonitrile gel, polyethylene oxide-based gel, polypropylene oxide-based gel, fluorine-based polymer gel, etc. There are.

[0228] Also, by using one or more ionic liquids (room temperature molten salts) that are flame-retardant and hardly volatile as a solvent for the electrolytic solution, even if the internal temperature rises due to an internal short circuit or overcharging of the power storage device etc., rupture or ignition of the power storage device can be prevented. An ionic liquid consists of a cation and an anion and contains an organic cation and an anion. As the organic cation used in the electrolytic solution, quaternary ammonium cation, tertiary sulfonium cation, and quaternary phosphonium cation, etc. aliphatic onium cations such as, and imidazolium cations and pyridinium cations, etc. aromatic cations. Also, as the anion used in the electrolytic solution, monovalent amide-based a nions, monovalent methide-based anions, fluorosulfonic acid anions, perfluoroalkyl sulfonic acid anions, tetrafluoroborate anions, perfluoroalkyl borate anions, hexafluorophosphate anions, or perfluoroalkyl phosphate anions, etc. can be mentioned.

[0229] ​In addition, when using lithium ions as carriers for the electrolyte dissolved in the above solvent , for example, LiPF6, LiClO4, LiAsF6, LiBF4, LiAlCl4, Li SCN, LiBr, LiI, Li2SO4, Li2B 10 Cl 10 , Li2B 12 Cl1 2, LiCF3SO3, LiC4F9SO3, LiC(CF3SO2)3, LiC(C2 F5SO2)3, LiN(CF3SO2)2, LiN(C4F9SO2)(CF3SO2 ), LiN(C2F5SO2)2, etc., can be used alone or in any combination and ratio of two or more of these .

[0230] In addition, it is preferable to use a highly purified electrolyte solution with a low content of particulate dust and elements other than the constituent elements of the electrolyte solution (hereinafter also simply referred to as "impurities"). Specifically, it is preferable that the weight ratio of impurities to the electrolyte solution is 1% or less, preferably 0.1% or less, more preferably 0.01% or less.

[0231] In addition, additives such as vinylene carbonate (VC), propane sultone (PS), tert- butylbenzene (TBB), fluoroethylene carbonate (FEC), LiBOB, etc. may be added to the electrolyte solution. The concentration of the additive may be, for example, 0.1 weight t% or more and 5 weight% or less based on the entire solvent.

[0232] In addition, a polymer gel electrolyte obtained by swelling a polymer with an electrolyte solution may be used.

[0233] Examples of the polymer include polyalkylene oxides such as polyethylene oxide (PEO). Polymers having a δ structure, such as PVdF and polyacrylonitrile, and copolymers containing them can be used. For example, PVdF-HFP, which is a copolymer of PVdF and hexafluoropropylene (H FP), can be used. Further, the formed polymer may have a porous shape. In addition, instead of the electrolytic solution, a solid electrolyte having an inorganic material such as a sulfide-based or oxide-based material, or a solid electrolyte having a polymer material such as a P EO (polyethylene oxide)-based material can be used. When using a solid electrolyte, it is not necessary to install a separator or a spacer. Also, since the entire battery can be solidified, the risk of leakage is eliminated and the safety is dramatically improved.

[0234] As the separator 507, for example, paper, non-woven fabric, glass fiber, ceramics, or synthetic fiber formed of nylon (polyamide), vinylon (polyvinyl alcohol-based fiber), polyester, acrylic, polyolefin, polyurethane, etc. can be used. The separator 507 is preferably processed into a bag shape and arranged to wrap either the positive electrode 503 or the negative electrode 506. For example, as shown in FIG. 7(A), the separator 507 is folded in half so as to sandwich the positive electrode 503, and sealed by a sealing portion 514 outside the region overlapping the positive electrode 503, so that the positive electrode 503 can be surely carried inside the bag of the separator 507 processed into a bag shape. Then, as shown in FIG. 7(B), the positive electrode 503 and the negative electrode 506 wrapped by the separator 507 are alternately laminated, and a thin battery 500 is preferably formed by arranging them inside the region surrounded by the exterior body 509. It is possible to use. Since the entire battery can be solidified, there is no risk of liquid leakage and the safety is dramatically improved.

[0235] As the separator 507, for example, those formed of paper, non-woven fabric, glass fiber, ceramics, or synthetic fibers using nylon (polyamide), vinylon (polyvinyl alcohol-based fiber), polyester, acrylic, polyolefin, polyurethane, etc. can be used. The separator 507 is preferably processed into a bag shape and arranged to wrap either the positive electrode 503 or the negative electrode 506. For example, as shown in FIG. 7(A), the separator 507 is folded in half so as to sandwich the positive electrode 503, and sealed by a sealing portion 514 outside the region overlapping the positive electrode 503, so that the positive electrode 503 can be surely carried inside the bag of the separator 507 processed into a bag shape. Then, as shown in FIG. 7(B), the positive electrode 503 and the negative electrode 506 wrapped by the separator 507 are alternately laminated, and a thin battery 500 is preferably formed by arranging them inside the region surrounded by the exterior body 509. It can be used. The separator 507 is preferably processed into a bag shape and arranged to wrap either the positive electrode 503 or the negative electrode 506. For example, as shown in FIG. 7(A), the separator 507 is folded in half so as to sandwich the positive electrode 503, and sealed by a sealing portion 514 outside the region overlapping the positive electrode 503, so that the positive electrode 503 can be surely carried inside the bag of the separator 507 processed into a bag shape. Then, as shown in FIG. 7(B), the positive electrode 503 and the negative electrode 506 wrapped by the separator 507 are alternately laminated, and a thin battery 500 is preferably formed by arranging them inside the region surrounded by the exterior body 509.

[0236] The separator 507 is preferably processed into a bag shape and arranged to wrap either the positive electrode 503 or the negative electrode 506. For example, as shown in FIG. 7(A), the separator 507 is folded in half so as to sandwich the positive electrode 503, and sealed by a sealing portion 514 outside the region overlapping the positive electrode 503, so that the positive electrode 503 can be surely carried inside the bag of the separator 507 processed into a bag shape. Then, as shown in FIG. 7(B), the positive electrode 503 and the negative electrode 506 wrapped by the separator 507 are alternately laminated, and a thin battery 500 is preferably formed by arranging them inside the region surrounded by the exterior body 509. For example, as shown in FIG. 7(A), the separator 507 is folded in half so as to sandwich the positive electrode 503, and sealed by a sealing portion 514 outside the region overlapping the positive electrode 503, so that the positive electrode 503 can be surely carried inside the bag of the separator 507 processed into a bag shape. The separator 507 is folded in half to sandwich the positive electrode 503, and sealed by a sealing portion 514 outside the region overlapping the positive electrode 503, so that the positive electrode 503 can be surely carried inside the bag of the separator 507 processed into a bag shape. The separator 507 is folded in half to sandwich the positive electrode 503, and sealed by a sealing portion 514 outside the region overlapping the positive electrode 503, so that the positive electrode 503 can be surely carried inside the bag of the separator 507 processed into a bag shape. Then, as shown in FIG. 7(B), the positive electrode 503 and the negative electrode 506 wrapped by the separator 507 are alternately laminated, and a thin battery 500 is preferably formed by arranging them inside the region surrounded by the exterior body 509. The positive electrode 503 and the negative electrode 506 wrapped by the separator 507 are alternately laminated, and a thin battery 500 is preferably formed by arranging them inside the region surrounded by the exterior body 509. A thin battery 500 is preferably formed by arranging them inside the region surrounded by the exterior body 509.

[0237] Here, as the positive electrode active material, particles having the lithium manganese composite oxide shown in Embodiment 1 are used, and as the positive electrode 503, the electrode shown in Embodiment 1 is used. An example in which a material having silicon is used as the negative electrode active material will be described. Here, as the positive electrode active material, particles having the lithium manganese composite oxide shown in Embodiment 1 are used, and as the positive electrode 503, the electrode shown in Embodiment 1 is used. An example in which a material having silicon is used as the negative electrode active material will be described. Here, as the positive electrode active material, particles having the lithium manganese composite oxide shown in Embodiment 1 are used, and as the positive electrode 503, the electrode shown in Embodiment 1 is used. An example in which a material having silicon is used as the negative electrode active material will be described.

[0238] A material having silicon, such as silicon or SiO, has a large capacity per active material weight and per active material volume, and can increase the capacity per weight and per volume of the storage battery. A material having silicon, such as silicon or SiO, has a large capacity per active material weight and per active material volume, and can increase the capacity per weight and per volume of the storage battery. A material having silicon, such as silicon or SiO, has a large capacity per active material weight and per active material volume, and can increase the capacity per weight and per volume of the storage battery.

[0239] Here, in the charge and discharge of the storage battery, in addition to the insertion / desorption reaction of carrier ions, a decomposition reaction of the electrolytic solution may occur. This decomposition reaction may occur at both the positive electrode and the negative electrode. Particularly at the negative electrode, the electrolytic solution often decomposes without having resistance to the low potential of the battery reaction. Such a decomposition reaction is often an irreversible reaction. The occurrence of an irreversible reaction reduces the charge / discharge efficiency of the power storage device and may cause a reduction in capacity. Here, in the charge and discharge of the storage battery, in addition to the insertion / desorption reaction of carrier ions, a decomposition reaction of the electrolytic solution may occur. This decomposition reaction may occur at both the positive electrode and the negative electrode. Particularly at the negative electrode, the electrolytic solution often decomposes without having resistance to the low potential of the battery reaction. Such a decomposition reaction is often an irreversible reaction. The occurrence of an irreversible reaction reduces the charge / discharge efficiency of the power storage device and may cause a reduction in capacity. Here, in the charge and discharge of the storage battery, in addition to the insertion / desorption reaction of carrier ions, a decomposition reaction of the electrolytic solution may occur. This decomposition reaction may occur at both the positive electrode and the negative electrode. Particularly at the negative electrode, the electrolytic solution often decomposes without having resistance to the low potential of the battery reaction. Such a decomposition reaction is often an irreversible reaction. The occurrence of an irreversible reaction reduces the charge / discharge efficiency of the power storage device and may cause a reduction in capacity. Here, in the charge and discharge of the storage battery, in addition to the insertion / desorption reaction of carrier ions, a decomposition reaction of the electrolytic solution may occur. This decomposition reaction may occur at both the positive electrode and the negative electrode. Particularly at the negative electrode, the electrolytic solution often decomposes without having resistance to the low potential of the battery reaction. Such a decomposition reaction is often an irreversible reaction. The occurrence of an irreversible reaction reduces the charge / discharge efficiency of the power storage device and may cause a reduction in capacity. Here, in the charge and discharge of the storage battery, in addition to the insertion / desorption reaction of carrier ions, a decomposition reaction of the electrolytic solution may occur. This decomposition reaction may occur at both the positive electrode and the negative electrode. Particularly at the negative electrode, the electrolytic solution often decomposes without having resistance to the low potential of the battery reaction. Such a decomposition reaction is often an irreversible reaction. The occurrence of an irreversible reaction reduces the charge / discharge efficiency of the power storage device and may cause a reduction in capacity. Here, in the charge and discharge of the storage battery, in addition to the insertion / desorption reaction of carrier ions, a decomposition reaction of the electrolytic solution may occur. This decomposition reaction may occur at both the positive electrode and the negative electrode. Particularly at the negative electrode, the electrolytic solution often decomposes without having resistance to the low potential of the battery reaction. Such a decomposition reaction is often an irreversible reaction. The occurrence of an irreversible reaction reduces the charge / discharge efficiency of the power storage device and may cause a reduction in capacity.

[0240] In such a case, it is preferable to prepare a battery provided in advance with the negative electrode 506 or the positive electrode 503 used in the storage battery, the counter electrode, and the electrolytic solution, cause an irreversible reaction to occur in advance, and then take out the negative electrode 506 or the positive electrode 503 from the battery to prepare the storage battery, because the reduction in the capacity of the storage battery due to the irreversible reaction can be suppressed. Here, as the counter electrode, a material having carrier ions may be used. For example, a metal having carrier ions or a compound having carrier ions can be used. As the metal having carrier ions, for example, In such a case, it is preferable to prepare a battery provided in advance with the negative electrode 506 or the positive electrode 503 used in the storage battery, the counter electrode, and the electrolytic solution, cause an irreversible reaction to occur in advance, and then take out the negative electrode 506 or the positive electrode 503 from the battery to prepare the storage battery, because the reduction in the capacity of the storage battery due to the irreversible reaction can be suppressed. Here, as the counter electrode, a material having carrier ions may be used. For example, a metal having carrier ions or a compound having carrier ions can be used. As the metal having carrier ions, for example, In such a case, it is preferable to prepare a battery provided in advance with the negative electrode 506 or the positive electrode 503 used in the storage battery, the counter electrode, and the electrolytic solution, cause an irreversible reaction to occur in advance, and then take out the negative electrode 506 or the positive electrode 503 from the battery to prepare the storage battery, because the reduction in the capacity of the storage battery due to the irreversible reaction can be suppressed. Here, as the counter electrode, a material having carrier ions may be used. For example, a metal having carrier ions or a compound having carrier ions can be used. As the metal having carrier ions, for example, In such a case, it is preferable to prepare a battery provided in advance with the negative electrode 506 or the positive electrode 503 used in the storage battery, the counter electrode, and the electrolytic solution, cause an irreversible reaction to occur in advance, and then take out the negative electrode 506 or the positive electrode 503 from the battery to prepare the storage battery, because the reduction in the capacity of the storage battery due to the irreversible reaction can be suppressed. Here, as the counter electrode, a material having carrier ions may be used. For example, a metal having carrier ions or a compound having carrier ions can be used. As the metal having carrier ions, for example, In such a case, it is preferable to prepare a battery provided in advance with the negative electrode 506 or the positive electrode 503 used in the storage battery, the counter electrode, and the electrolytic solution, cause an irreversible reaction to occur in advance, and then take out the negative electrode 506 or the positive electrode 503 from the battery to prepare the storage battery, because the reduction in the capacity of the storage battery due to the irreversible reaction can be suppressed. Here, as the counter electrode, a material having carrier ions may be used. For example, a metal having carrier ions or a compound having carrier ions can be used. As the metal having carrier ions, for example, In such a case, it is preferable to prepare a battery provided in advance with the negative electrode 506 or the positive electrode 503 used in the storage battery, the counter electrode, and the electrolytic solution, cause an irreversible reaction to occur in advance, and then take out the negative electrode 506 or the positive electrode 503 from the battery to prepare the storage battery, because the reduction in the capacity of the storage battery due to the irreversible reaction can be suppressed. Here, as the counter electrode, a material having carrier ions may be used. For example, a metal having carrier ions or a compound having carrier ions can be used. As the metal having carrier ions, for example, For example, lithium can be mentioned. In addition, examples of compounds having carrier ions include The materials exemplified as the positive electrode active material and the negative electrode active material in the first embodiment can be used.

[0241] Next, aging after the storage battery is manufactured will be described. An example of the aging conditions is described below. Charge at a rate of 0.001C to 0.2C. The temperature is, for example, above room temperature, 50℃ If the electrolyte decomposes and gas is generated, the gas should be If gas accumulates in the cell, areas will be created where the electrolyte cannot come into contact with the electrode surface. In other words, the effective reaction area of ​​the electrode decreases, which corresponds to an increase in effective resistance. In addition, the particles having the lithium manganese composite oxide according to one embodiment of the present invention can be used as a positive electrode active material. When the positive electrode active material has a high reaction potential, This is preferable because it can increase the voltage of the storage battery and increase the energy density of the storage battery. I wish.

[0242] Here, there are cases where the electrolyte does not have resistance to such a high reaction potential. For example, In some cases, the electrolyte may decompose on the surface of the positive electrode, generating gas. It is preferable to degas the mixture.

[0243] In addition, if the resistance becomes too high, the negative electrode potential will decrease, preventing lithium from being inserted into the graphite. At the same time, lithium deposition occurs on the graphite surface. This lithium deposition causes a decrease in capacity. For example, if a film or the like grows on the surface after lithium is deposited, the surface The lithium deposited on the surface cannot be redissolved, and the amount of lithium that does not contribute to the capacity increases. Also , even when the deposited lithium physically collapses and loses electrical connection with the electrode, lithium that does not contribute to the capacity is still generated. Therefore, it is preferable to vent the gas before the negative electrode potential reaches the lithium potential due to the increase in the charging voltage.

[0244] Also, aging may be performed while applying pressure. For example, after manufacturing a thin rechargeable battery, charge and discharge may be performed while applying pressure using a press.

[0245] The lithium manganese composite oxide according to one aspect of the present invention has a large discharge capacity, which is preferable. Also, the lithium manganese composite oxide according to one aspect of the present invention has a high potential for the battery reaction and a high energy density, which is preferable.

[0246] On the other hand, when using an active material with a high battery reaction potential as the positive electrode of a rechargeable battery, the electrolyte may be easily decomposed. Here, when the electrolyte decomposes, gas may be generated near the surface of the positive electrode.

[0247] By performing aging while applying pressure, the generated gas may be expelled to a region other than the region where pressure is being applied, for example, the peripheral portion of the rechargeable battery, which is preferable.

[0248] Here, for example, pressure may be applied while heating. Also, pressure may be applied before and after aging, but it is more preferable to perform aging while applying pressure.

[0249] Also, after venting the gas, at a temperature higher than room temperature, preferably 30°C or higher and 60°C or lower, ​​​​​​​​​More preferably, it may be maintained at 35°C or higher and 50°C or lower for, for example, 1 hour or longer and 100 hours or shorter, in a charged state. During the first charging, the electrolytic solution decomposed on the surface forms a coating on the surface of the graphite. Therefore, for example, by maintaining at a temperature higher than room temperature after gas venting, the formed coating may become denser.

[0250] As shown in FIG. 8(A), the positive electrode current collector of the positive electrode 503 is welded to the positive electrode lead electrode 510 in the welding region 512 using ultrasonic welding or the like. The negative electrode current collector of the negative electrode 506 is welded to the negative electrode lead electrode 511. FIG. 8(B) shows an example of welding a current collector to a lead electrode. As an example, an example of welding a positive electrode current collector to the positive electrode lead electrode 510 is shown. Further, since the positive electrode current collector has the curved portion 513 shown in FIG. 8(B), the stress generated by an external force applied after the production of the storage battery 500 can be relaxed, and the reliability of the storage battery 500 can be improved.

[0251] In the thin storage battery 500 shown in FIGS. 5 and 6, the positive electrode lead electrode 510 is ultrasonically welded to the positive electrode current collector 501 of the positive electrode 503, and the negative electrode lead electrode 511 is ultrasonically welded to the negative electrode current collector 504 of the negative electrode 506, respectively. Also, the role of the terminal for obtaining electrical contact with the outside can be served by the positive electrode current collector 501 and the negative electrode current collector 504. In that case, in any case of using a lead electrode, a part of the positive electrode current collector 501 and the negative electrode current collector 504 may be arranged to be exposed to the outside from the exterior body 509.

[0252] Also, in FIG. 5, the positive electrode lead electrode 510 and the negative electrode lead electrode 511 are arranged on the same side, but as shown in FIG. 9, the positive electrode lead electrode 510 and the negative electrode lead electrode 511 are arranged on different sides. ​​​​​​​​​​​may be used. Thus, in one aspect of the present invention, the storage battery can freely arrange the lead electrodes Therefore, the degree of design freedom is high. Therefore, the degree of design freedom of products using the storage battery according to one aspect of the present invention can be increased. In addition, the productivity of products using the storage battery according to one aspect of the present invention can be increased. Moreover, the productivity of products using the storage battery according to one aspect of the present invention can be increased. In the thin storage battery 500, for the exterior body 509, for example, on a film made of a material such as polyethylene, polypropylene

[0253] , polycarbonate, ionomer, polyamide, etc., a metal thin film excellent in flexibility such as aluminum , stainless steel, copper, nickel, etc. is provided, and further on the metal thin film an insulating synthetic resin film such as a polyamide-based resin or a polyester-based resin is provided as the outer surface of the exterior body and a three-layer film can be used. In FIG. 6, as an example, the number of pairs of the facing positive electrode active material layer and negative electrode active material layer is set to 5 pairs

[0254] , but of course, the number of pairs of the active material layers is not limited to 5 pairs, and may be more or less. When the number of active material layers is large, a storage battery having a larger capacity can be obtained. Also, when the number of active material layers is small, it can be made thinner and a storage battery excellent in flexibility can be obtained. In the above configuration, the exterior body 509 of the storage battery 500 can be deformed within a range where the radius of curvature is 30 mm or more, preferably

[0255] the radius of curvature is 10 mm or more. The film that is the exterior body of the storage battery is composed of one or two sheets. In the case of a laminated storage battery, the cross-sectional structure of the curved battery is a structure sandwiched between two curves of the film that is the exterior body. The radius of curvature of the surface will be described with reference to FIG. 10. In FIG. 10(A), the curved surface 1700

[0256] will be described with reference to FIG. 10. In FIG. 10(A), the curved surface 1700 A part of a curve 1702 included in the surface 1700 is cut into a plane 1701 by an arc of a circle. The radius of the circle is the radius of curvature 1703, and the center of the circle is the center of curvature 1704. FIG. 10B shows a top view of the curved surface 1700. FIG. 10C shows the curved surface 1 When cutting a curved surface with a plane, the angle of the plane to the curved surface and The radius of curvature of the curve that appears in the cross section varies depending on the cutting position. , the smallest radius of curvature is taken as the radius of curvature of the surface.

[0257] When a storage battery with two sheets of film as the exterior body and electrodes, electrolyte, etc. sandwiched between 1805 is curved The radius of curvature 1802 of the film 1801 on the side closer to the center of curvature 1800 of the battery is The radius of curvature 1804 of the film 1803 on the side farther from the center of curvature 1800 is smaller than that of the film 1803 (FIG. 11 (A) When the battery is bent to make the cross section an arc, the film close to the center of curvature 180° The surface is subjected to compressive stress, and the surface of the film far from the center of curvature 1800 is subjected to tensile stress. (Fig. 11(B)) A pattern consisting of concave or convex parts is formed on the surface of the exterior body. Even if compressive or tensile stress is applied, the effect of strain is within the acceptable range. Therefore, the storage battery can be kept within the radius of curvature of the exterior body on the side closer to the center of curvature. The deformation can be in the range of 30 mm or more, preferably the radius of curvature can be in the range of 10 mm or more.

[0258] The cross-sectional shape of the storage battery is not limited to a simple arc shape, and may be a shape that includes a partial arc. For example, the shape shown in FIG. 11(C), a wavy shape (FIG. 11(D)), an S-shape, etc. If the curved surface of the storage battery has a shape with multiple centers of curvature, Among the radii of curvature at each rate center, on the surface with the smallest radius of curvature, for the two outer packages, the radius of curvature of the outer package closer to the center of curvature is preferably 30 mm or more, more preferably 10 mm or more, and within this range, the storage battery can be deformed.

[0259] [Thin-type storage battery 2] In FIG. 12, as an example of a thin-type storage battery different from FIG. 5, a storage battery 100a is shown. FIG. 12(A) is a perspective view of the storage battery 100a, and FIG. 12(B) is a top view of the storage battery 100a. FIG. 12(C ) is a cross-sectional view taken along the dashed line D1-D2 in FIG. 12(B). In FIG. 12(C), for clarity of the figure, the positive electrode 111, the negative electrode 115, the separator 103, the positive electrode lead 121 , the negative electrode lead 125, and the sealing layer 120 are shown in an extracted manner.

[0260] Here, using FIG. 13, a part of the manufacturing method of the storage battery 100a shown in FIG. 12 will be described. .

[0261] First, the negative electrode 115 is disposed on the separator 103 (FIG. 13(A)). At this time, the negative electrode active material layer of the negative electrode 1 15 is disposed so as to overlap the separator 103.

[0262] Next, the separator 103 is bent and the separator 103 is placed on the negative electrode 115. Next, , the positive electrode 111 is placed on the separator 103 (FIG. 13(B)). At this time, the positive electrode active material layer of the positive electrode 1 11 is disposed so as to overlap the separator 103 and the negative electrode active material layer. When using an electrode in which an active material layer is formed on one side of the current collector, the positive electrode active material layer of the positive electrode 111 and the negative electrode active material layer of the negative electrode 115 are disposed so as to face each other with the separator 103 interposed therebetween.

[0263] When a material capable of heat welding such as polypropylene is used for the separator 103, by heat welding the overlapping regions of the separators 103 and then stacking the next electrode, the displacement of the electrodes during the manufacturing process can be suppressed. Specifically, it is preferably to heat weld the region where the separators 103 overlap but do not overlap with the negative electrode 115 or the positive electrode 111, for example, the region 103a shown in FIG. 13(B). By heat welding the overlapping regions of the separators 103 and then stacking the next electrode, the displacement of the electrodes during the manufacturing process can be suppressed. Specifically, it does not overlap with the negative electrode 115 or the positive electrode 111, and it is preferable to heat weld the region where the separators 103 overlap, for example, the region shown by 103a in FIG. 13(B). By repeating this process, as shown in FIG. 13(C), the positive electrode 111 and the negative electrode 115 can be stacked with the separator 103 in between. It should be noted that a plurality of negative electrodes 115 and a plurality of positive electrodes 111 may be alternately arranged and sandwiched between the separators 103 that have been repeatedly bent in advance.

[0264] By repeating this process, as shown in FIG. 13(C), the positive electrode 111 and the negative electrode 115 can be stacked with the separator 103 in between. Specifically, it does not overlap with the negative electrode 115 or the positive electrode 111, and it is preferable to heat weld the region where the separators 103 overlap, for example, the region shown by 103a in FIG. 13(B).

[0265] It should be noted that a plurality of negative electrodes 115 and a plurality of positive electrodes 111 may be alternately arranged and sandwiched between the separators 103 that have been repeatedly bent in advance. Next, as shown in FIG. 13(C), cover the plurality of positive electrodes 111 and the plurality of negative electrodes 115 with the separator 103.

[0266] Next, as shown in FIG. 13(C), cover the plurality of positive electrodes 111 and the plurality of negative electrodes 115 with the separator 103. Next, as shown in FIG. 13(D), by heat welding the overlapping regions of the separators 103, for example, the region 103b shown in FIG. 13(D), the plurality of positive electrodes 111 and the plurality of negative electrodes 115 are covered and bound by the separator 103.

[0267] Next, as shown in FIG. 13(D), by heat welding the overlapping regions of the separators 103, for example, the region 103b shown in FIG. 13(D), the plurality of positive electrodes 111 and the plurality of negative electrodes 115 are covered and bound by the separator 103. Next, as shown in FIG. 13(D), by heat welding the overlapping regions of the separators 103, for example, the region 103b shown in FIG. 13(D), the plurality of positive electrodes 111 and the plurality of negative electrodes 115 are covered and bound by the separator 103. It should be noted that the plurality of positive electrodes 111, the plurality of negative electrodes 115, and the separator 103 may be bound using a binding material.

[0268] It should be noted that the plurality of positive electrodes 111, the plurality of negative electrodes 115, and the separator 103 may be bound using a binding material. It should be noted that the plurality of positive electrodes 111, the plurality of negative electrodes 115, and the separator 103 may be bound using a binding material.

[0269] In order to stack the positive electrode 111 and the negative electrode 115 in such a process, the separator 103, within one separator 103, has the region sandwiched between the positive electrode 111 and the negative electrode 115, and a plurality of In order to stack the positive electrode 111 and the negative electrode 115 in such a process, the separator 103, within one separator 103, has the region sandwiched between the positive electrode 111 and the negative electrode 115, and a plurality of It has a region that is arranged to cover the positive electrode 111 and the plurality of negative electrodes 115.

[0270] In other words, the separator 103 included in the storage battery 100a in FIG. 12 is a single separator that is partially folded. A plurality of positive electrodes 111 and a plurality of negative electrodes 115 are sandwiched between the folded regions of the separator 103.

[0271] Regarding the bonding region of the exterior body 107 of the storage battery 100a, and the shapes of the positive electrode 111, the negative electrode 115, the separator 103, and the exterior body 107, and the positional shapes of the positive electrode lead 121 and the negative electrode lead 125, the description in Embodiment 1 can be referred to. Further, regarding the manufacturing method of the storage battery 100a other than the step of stacking the positive electrode 111 and the negative electrode 115, the manufacturing methods described in other embodiments can be referred to.

[0272] [Thin-type storage battery 3] FIG. 14 shows a storage battery 100b as an example of a thin-type storage battery different from that in FIG. 12. FIG. 14(A) is a perspective view of the storage battery 100b, and FIG. 14(B) is a top view of the storage battery 100b. FIG. 14(C1) is a cross-sectional view of the first electrode assembly 130, and FIG. 14(C2) is a cross-sectional view of the second electrode assembly 131. FIG. 14(D) is a cross-sectional view taken along the dashed line E1-E2 in FIG. 14(B). Note that in FIG. 14(D), for clarity of the drawing, the first electrode assembly 130, the second electrode assembly 131, and the separator 103 are shown in an extracted manner.

[0273] In the storage battery 100b shown in FIG. 14, the arrangements of the positive electrode 111 and the negative electrode 115 and the arrangement of the separator 103 are different from those of the storage battery 100a in FIG. 12.

[0274] As shown in FIG. 14(D), the storage battery 100b has a plurality of first electrode assemblies 130 and a plurality of second electrode assemblies 131.

[0275] As shown in FIG. 14(C1), in the first electrode assembly 130, a positive electrode 111a having a positive electrode active material layer on both sides of a positive electrode current collector, a separator 103, a negative electrode 115a having a negative electrode active material layer on both sides of a negative electrode current collector, a separator 103, and a positive electrode 111a having a positive electrode active material layer on both sides of a positive electrode current collector are laminated in this order. Further, as shown in FIG. 14(C2), in the second electrode assembly 131, a negative electrode 115a having a negative electrode active material layer on both sides of a negative electrode current collector, a separator 103, a positive electrode 111a having a positive electrode active material layer on both sides of a positive electrode current collector, a separator 103, and a negative electrode 115a having a negative electrode active material layer on both sides of a negative electrode current collector are laminated in this order.

[0276] Furthermore, as shown in FIG. 14(D), the plurality of first electrode assemblies 130 and the plurality of electrode assemblies 131 are covered with a wound separator 103.

[0277] Here, using FIG. 15, a part of the manufacturing method of the storage battery 100b shown in FIG. 14 will be described.

[0278] First, the first electrode assembly 130 is disposed on the separator 103 (FIG. 15(A)).

[0279] Next, the separator 103 is bent and the separator 103 is overlapped on the first electrode assembly 130. Next, two sets of second electrode assemblies 131 are overlapped via the separator 103 above and below the first electrode assembly 130 (FIG. 15(B)).

[0280] Next, the separator 103 is wound so as to cover the two sets of second electrode assemblies 131. Further, above and below the two sets of second electrode assemblies 131, two sets of first electrode assemblies 130 are stacked via separators 103 (FIG. 15(C)).

[0281] Next, the separator 103 is wound so as to cover the two sets of first electrode assemblies 130 (FIG. 15(D)).

[0282] In such a process, in order to stack a plurality of first electrode assemblies 130 and a plurality of second electrode assemblies 131, these electrode assemblies are arranged between the separators 103 wound in a spiral shape.

[0283] Note that it is preferable that the positive electrode 111a of the first electrode assembly 130 arranged on the outermost side does not have a positive electrode active material layer on the outside.

[0284] Also, in FIGS. 14(C1) and (C2), the configuration in which the electrode assembly has three electrodes and two separators is shown, but one aspect of the present invention is not limited to this. The configuration may have four or more electrodes and three or more separators. By increasing the number of electrodes, the capacity of the storage battery 100b can be further improved. Also, the configuration may have two electrodes and one separator. When the number of electrodes is small, the storage battery 100b can be made more resistant to bending. Also, in FIG. 14(D), the configuration in which the storage battery 100b has three sets of first electrode assemblies 130 and two sets of second electrode assemblies 131 is shown, but one aspect of the present invention is not limited to this. A configuration having an even larger number of electrode assemblies may be used. By increasing the number of electrode assemblies, the capacity of the storage battery 100b can be further improved. Also, a configuration having an even smaller number of electrode assemblies may be used. When the number of electrode assemblies is small, the storage battery 100b can be made more resistant to bending. ​​​​​​​​​​​​

[0285] The arrangement of the positive electrode 111a and the negative electrode 115a of the storage battery 100b, and the arrangement of the separator 103 For the rest, the description about FIG. 12 can be referred to.

[0286] 〈Coin-type storage battery〉 Next, as an example of the power storage device, an example of a coin-type storage battery will be described with reference to FIG. 16. FIG. 16(A) is an external view of a coin-type (single-layer flat type) storage battery, and FIG. 16(B) is its cross-sectional view.

[0287] The coin-type storage battery 300 has a positive electrode can 301 that also serves as a positive electrode terminal and a negative electrode can 3 02 that also serves as a negative electrode terminal, which are insulated and sealed with a gasket 303 made of polypropylene or the like. The positive electrode 304 is formed by a positive electrode current collector 305 and a positive electrode active material layer 306 provided in contact therewith. For the positive electrode active material layer 306, reference may be made to the description of the positive electrode active material layer 502.

[0288] Also, the negative electrode 307 is formed by a negative electrode current collector 308 and a negative electrode active material layer 309 provided in contact therewith. For the negative electrode active material layer 309, reference may be made to the description of the negative electrode active material layer 505. Also, for the separator 310, reference may be made to the description of the separator 507. Also, for the electrolyte reference may be made to the description of the electrolyte 508.

[0289] Note that for the positive electrode 304 and the negative electrode 307 used in the coin-type storage battery 300, the active material layers may be formed only on one side.

[0290] The positive electrode can 301 and the negative electrode can 302 are made of metals such as nickel, aluminum, titanium, etc. that are corrosion-resistant to the electrolyte, or alloys of these or alloys of these and other metals (for example, stainless steel Steel or the like can be used. Also, in order to prevent corrosion by the electrolytic solution, it is preferable to coat with nickel, aluminum, or the like. The positive electrode can 301 is electrically connected to the positive electrode 304, and the negative electrode can 302 is electrically connected to the negative electrode 307. These negative electrode 307, positive electrode 304, and separator 310 are impregnated with the electrolyte, and as shown in FIG. 16(B), with the positive electrode can 301 facing downwards, the positive electrode 304, separator 310, negative electrode 307, negative electrode can 302 are laminated in this order, and the positive electrode can 301 and the negative electrode can 302 are crimped via the gasket 303 to manufacture the coin-shaped battery 300.

[0291] These negative electrode 307, positive electrode 304, and separator 310 are impregnated with the electrolyte, and as shown in FIG. 16(B), with the positive electrode can 301 facing downwards, the positive electrode 304, separator 310, negative electrode 307, ) to manufacture the coin-shaped battery 300. negative electrode can 302 are laminated in this order, and the positive electrode can 301 and the negative electrode can 302 are crimped via the gasket 303 to manufacture the coin-shaped battery 300. negative electrode can 302 are laminated in this order, and the positive electrode can 301 and the negative electrode can 302 are crimped via the gasket 303 to manufacture the coin-shaped battery 300.

[0292] 〈Cylindrical battery〉 Next, as an example of the power storage device, a cylindrical battery is shown. The cylindrical battery will be described with reference to FIG. 17. The cylindrical battery 600 has a positive electrode cap (battery lid) 601 on the upper surface and a battery can (outer can) 602 on the side surface and the bottom surface as shown in FIG. 17(A). These positive electrode cap 601 and battery can (outer can) 602 are insulated by a gasket (insulating packing) 610. These positive electrode cap 601 and battery can (outer can) 602 are insulated by a gasket (insulating packing) 610. These positive electrode cap 601 and battery can (outer can) 602 are insulated by a gasket (insulating packing) 610. These positive electrode cap 601 and battery can (outer can) 602 are insulated by a gasket (insulating packing) 610.

[0293] FIG. 17(B) is a diagram schematically showing a cross section of the cylindrical battery. Inside the hollow cylindrical battery can 602, a battery element in which a strip-shaped positive electrode 604 and a negative electrode 606 are wound with a separator 605 in between is provided. Although not shown, the battery element is wound around a center pin. One end of the battery can 602 is closed and the other end is open. For the battery can 602, metals such as nickel, aluminum, and titanium that are corrosion-resistant to the electrolytic solution, or alloys of these or alloys of these and other metals (for example, stainless steel or the like) can be used. Inside the hollow cylindrical battery can 602, a battery element in which a strip-shaped positive electrode 604 and a negative electrode 606 are wound with a separator 605 in between is provided. Although not shown, the battery element is wound around a center pin. One end of the battery can 602 is closed and the other end is open. For the battery can 602, metals such as nickel, aluminum, and titanium that are corrosion-resistant to the electrolytic solution, or alloys of these or alloys of these and other metals (for example, stainless steel or the like) can be used. Inside the hollow cylindrical battery can 602, a battery element in which a strip-shaped positive electrode 604 and a negative electrode 606 are wound with a separator 605 in between is provided. Although not shown, the battery element is wound around a center pin. One end of the battery can 602 is closed and the other end is open. For the battery can 602, metals such as nickel, aluminum, and titanium that are corrosion-resistant to the electrolytic solution, or alloys of these or alloys of these and other metals (for example, stainless steel or the like) can be used. Inside the hollow cylindrical battery can 602, a battery element in which a strip-shaped positive electrode 604 and a negative electrode 606 are wound with a separator 605 in between is provided. Although not shown, the battery element is wound around a center pin. One end of the battery can 602 is closed and the other end is open. For the battery can 602, metals such as nickel, aluminum, and titanium that are corrosion-resistant to the electrolytic solution, or alloys of these or alloys of these and other metals (for example, stainless steel or the like) can be used. Inside the hollow cylindrical battery can 602, a battery element in which a strip-shaped positive electrode 604 and a negative electrode 606 are wound with a separator 605 in between is provided. Although not shown, the battery element is wound around a center pin. One end of the battery can 602 is closed and the other end is open. For the battery can 602, metals such as nickel, aluminum, and titanium that are corrosion-resistant to the electrolytic solution, or alloys of these or alloys of these and other metals (for example, stainless steel or the like) can be used. Inside the hollow cylindrical battery can 602, a battery element in which a strip-shaped positive electrode 604 and a negative electrode 606 are wound with a separator 605 in between is provided. Although not shown, the battery element is wound around a center pin. One end of the battery can 602 is closed and the other end is open. For the battery can 602, metals such as nickel, aluminum, and titanium that are corrosion-resistant to the electrolytic solution, or alloys of these or alloys of these and other metals (for example, stainless steel or the like) can be used. In addition, in order to prevent corrosion by the electrolytic solution, it is preferable to coat nickel, aluminum, or the like. Inside the battery can 602, the battery element in which the positive electrode, negative electrode, and separator are wound is sandwiched between a pair of opposing insulating plates 608 and 609. Further, the inside of the battery can 602 where the battery element is provided is filled with a non-aqueous electrolytic solution (not shown). As the non-aqueous electrolytic solution, the same one as that used in a coiled type storage battery can be used.

[0294] The positive electrode 604 and the negative electrode 606 may be manufactured in the same manner as the positive electrode and negative electrode of the thin type storage battery described above. Further, since the positive electrode and negative electrode used in the cylindrical storage battery are wound, it is preferable to form the active material on both sides of the current collector. A positive electrode terminal (positive electrode current collecting lead) 603 is connected to the positive electrode 604, and a negative electrode terminal (negative electrode current collecting lead) 607 is connected to the negative electrode 606. Both the positive electrode terminal 603 and the negative electrode terminal 607 can be made of a metal material such as aluminum. The positive electrode terminal 603 is resistance welded to the safety valve mechanism 612, and the negative electrode terminal 607 is resistance welded to the bottom of the battery can 602, respectively. The safety valve mechanism 612 is electrically connected to the positive electrode cap 601 via a PTC element (Positive Temperature Coefficient) 611. The safety valve mechanism 612 disconnects the electrical connection between the positive electrode cap 601 and the positive electrode 604 when the internal pressure of the battery rises above a predetermined threshold value. Further, the PTC element 611 is a thermal sensing resistance element whose resistance increases when the temperature rises, and restricts the electric current flow to prevent abnormal heat generation by the increase in resistance. As the PTC element, barium titanate (BaTiO3)-based semiconductor ceramics or the like can be used.

[0295] When winding electrodes like a cylindrical battery as shown in Fig. 17, large stress acts on the electrodes during winding. Also, when the wound electrode body is housed in a casing, stress always acts on the electrodes toward the outside of the winding axis. Even if such large stress acts on the electrodes, it is possible to prevent the active material from splitting.

[0296] In this embodiment, coin-type, cylindrical, and thin-type batteries are shown as the battery, but batteries of various shapes such as other sealed batteries and rectangular batteries can be used. Also, a structure in which a plurality of positive electrodes, negative electrodes, and separators are stacked, or a structure in which a positive electrode, a negative electrode, and a separator are wound may be used. For example, examples of other batteries are shown in Figs. 18 to 22.

[0297] 〈Configuration Example of Battery〉 Figs. 18 and 19 show a configuration example of a thin battery. The wound body 993 shown in Fig. 18(A) has a negative electrode 994, a positive electrode 995, and a separator 996.

[0298] In the wound body 993, the negative electrode 994 and the positive electrode 995 overlap with each other with the separator 996 in between and are stacked, and the stacked sheet is wound. By covering this wound body 993 with a rectangular sealed container or the like a rectangular battery is manufactured.

[0299] Note that the number of stacked layers of the stack composed of the negative electrode 994, the positive electrode 995, and the separator 996 may be appropriately designed according to the required capacity and the element volume. The negative electrode 994 is connected to a negative electrode current collector (not shown) via one of the lead electrodes 997 and 998, and the positive electrode 995 is connected to a positive electrode current collector (not shown) via the other of the lead electrodes 997 and 998. ​​​​

[0300] The storage battery 990 shown in FIGS. 18(B) and 18(C) is formed by thermocompression bonding or the like a film 981 serving as an exterior body and a film 982 having a recess, and the above-described wound body 993 is housed in the space formed. The wound body 993 has lead electrodes 997 and lead electrodes 998, and is impregnated with an electrolytic solution inside the film 981 and the film 982 having a recess.

[0301] As the film 981 and the film 982 having a recess, a metal material such as aluminum or a resin material can be used. If a resin material is used as the material of the film 981 and the film 982 having a recess, when a force is applied from the outside, the film 981 and the film 982 having a recess can be deformed, and a flexible storage battery can be manufactured.

[0302] Also, FIGS. 18(B) and 18(C) show an example using two films, but a space may be formed by bending a single film, and the above-described wound body 99 3 may be housed in the space.

[0303] Further, in a power storage device in which only the flexible portion is a thin power storage battery, a flexible power storage device can be manufactured by using a resin material or the like for the exterior body and the sealing container. However, when the exterior body and the sealing container are made of a resin material, the portion connected to the outside is made of a conductive material.

[0304] For example, FIG. 19 shows an example of another thin flexible storage battery. Since the wound body 99 3 shown in FIG. 19(A) is the same as that shown in FIG. 18(A), detailed description will be omitted. ​​​​​​​​​​

[0305] The storage battery 990 shown in FIGS. 19(B) and 19(C) has the above-described wound body 993 housed inside the exterior body 991. The wound body 993 has lead electrodes 997 and lead electrodes 998, and is impregnated with an electrolytic solution inside the exterior bodies 991 and 9 92. As the exterior bodies 991 and 9 92, a metal material such as aluminum or a resin material can be used. If a resin material is used as the material of the exterior bodies 99 1 and 992, the exterior bodies 991 and 992 can be deformed when an external force is applied, and a thin flexible storage battery can be manufactured. .

[0306] By using the electrode containing the active material according to one aspect of the present invention in a thin flexible storage battery, even if stress acts on the electrode by repeatedly bending the thin flexible storage battery, it is possible to prevent the active material from splitting.

[0307] As described above, by using the active material covered with graphene on at least a part of the cleavage surface for the electrode, it is possible to suppress a decrease in the voltage of the battery and a decrease in the discharge capacity. Thereby, the cycle characteristics of the battery associated with charge and discharge can be improved.

[0308] <Example of the structure of the power storage system> In addition, an example of the structure of the power storage system will be described with reference to FIGS. 20 to 22. Here, the power storage system refers to, for example, a device equipped with a power storage device.

[0309] FIGS. 20(A) and 20(B) are external views of the power storage system. The power storage system has a circuit substrate 900 and a storage battery 913. A label 910 is attached to the storage battery 913. is provided. Further, as shown in FIG. 20(B), the power storage system includes a terminal 951, a terminal 95 2, an antenna 914, and an antenna 915.

[0310] The circuit board 900 includes a terminal 911 and a circuit 912. The terminal 911 is connected to the terminal 951 , the terminal 952, the antenna 914, the antenna 915, and the circuit 912. Note that , a plurality of terminals 911 may be further provided, and each of the plurality of terminals 911 may be used as a control signal input terminal, a power supply terminal, etc.

[0311] The circuit 912 may be provided on the back surface of the circuit board 900. Note that the antenna 914 and the antenna 915 are not limited to a coil shape, and may be, for example, linear or plate-shaped. Also , an antenna such as a planar antenna, an aperture antenna, a traveling wave antenna, an EH antenna, a magnetic field antenna, a dielectric body antenna, etc. may be used. Or, the antenna 914 or the antenna 915 may be a flat conductor. This flat conductor can function as one of the conductors for electric field coupling. That is, the antenna 914 or the antenna 915 may function as one of the two conductors of the capacitor. Thereby, not only electromagnetic fields and magnetic fields , but also power exchange can be performed by an electric field.

[0312] The line width of the antenna 914 is preferably larger than the line width of the antenna 915. Thereby , the amount of power received by the antenna 914 can be increased.

[0313] The power storage system has a layer 91 6 between the antennas 914 and 915 and the battery 913. The layer 916 can function to shield, for example, the electromagnetic field generated by the battery 913. It has. As the layer 916, for example, a magnetic material can be used.

[0314] Note that the structure of the power storage system is not limited to the structure shown in FIG. 20.

[0315] For example, as shown in FIGS. 21(A-1) and 21(A-2), among the storage batteries 913 shown in FIGS. 20(A) and 20(B), antennas may be provided on each of a pair of opposing surfaces. FIG. 21(A-1) is an external view seen from one side direction of the pair of surfaces, and FIG. 21 (A-2) is an external view seen from the other side direction of the pair of surfaces. Note that for the same parts as the power storage system shown in FIGS. 20(A) and 20(B), the description of the power storage system shown in FIGS. 20(A) and 20 (B) can be appropriately incorporated.

[0316] As shown in FIG. 21(A-1), an antenna 914 is provided with a layer 916 sandwiched between a pair of surfaces of the storage battery 913, and as shown in FIG. 21(A-2), an antenna 915 is provided with a layer 917 sandwiched between the other of the pair of surfaces of the storage battery 913. The layer 917 has a function of being able to shield the electromagnetic field caused by, for example, the storage battery 913. As the layer 917, for example, a magnetic material can be used

[0317] By adopting the above structure, the sizes of both the antenna 914 and the antenna 915 can be increased

[0318] Alternatively, as shown in FIGS. 21(B-1) and 21(B-2), among the storage batteries 913 shown in FIGS. 20(A) and 20(B), different antennas may be provided on each of a pair of opposing surfaces. FIG. 21(B-1) is an external view seen from one side direction of the pair of surfaces, and FIG. 21(B-2) is an external view seen from the other side direction of the pair of surfaces. ​​​​21(B-2) is an external view seen from the other side direction of the pair of surfaces. For the same parts as the power storage system shown in FIGS. 20(A ) and 20(B), the description of the power storage system shown in FIGS. 20(A) and 20(B) can be appropriately incorporated by reference.

[0319] As shown in FIG. 21(B-1), antennas 914 and 915 are provided with a layer 916 sandwiched between one of the pair of surfaces of the storage battery 913, and as shown in FIG. 21(B-2), an antenna 918 is provided with a layer 917 sandwiched between the other of the pair of surfaces of the storage battery 9 13. The antenna 918 has a function of, for example, being able to perform data communication with an external device. The antenna 918 can be applied with an antenna having a shape applicable to, for example, the antennas 914 and 915. As a communication method between the power storage system and other devices via the antenna 918 , a response method or the like that can be used between the power storage system and other devices, such as NFC, can be applied. , a response method or the like that can be used between the power storage system and other devices, such as NFC, can be applied.

[0320] Alternatively, as shown in FIG. 22(A), a display device 920 may be provided on the storage battery 913 shown in FIGS. 20(A) and 20(B). The display device 920 is electrically connected to the terminal 911 via the terminal 919. Note that a label 910 may not be provided at the portion where the display device 920 is provided. For the same parts as the power storage system shown in FIGS. 20(A) and 20(B), the description of the power storage system shown in FIGS. 20(A) and 20(B) can be appropriately incorporated by reference. 20(B) can be appropriately incorporated by reference.

[0321] The display device 920 may display, for example, an image indicating whether charging is in progress, an image indicating the remaining charge amount, etc. As the display device 920, for example, electronic paper, a liquid crystal display device, an electr onic A luminescence (also referred to as EL) display device or the like can be used. For example, by using an electronic paper the power consumption of the display device 920 can be reduced.

[0322] Alternatively, as shown in Fig. 22(B), a sensor 921 may be provided in the storage battery 913 shown in Figs. 20(A) and 20(B). The sensor 921 is electrically connected to the terminal 911 via the terminal 922. Note that for the same parts as the power storage system shown in Figs. 20(A) and 20(B), the description of the power storage system shown in Figs. 20(A) and 20(B) can be appropriately incorporated.

[0323] As the sensor 921, for example, one including a function of measuring force, displacement, position, speed, acceleration, angular velocity, rotation speed, distance , light, liquid, magnetism, temperature, chemical substance, sound, time, hardness, electric field, current, voltage, power, radiation , flow rate, humidity, gradient, vibration, odor or infrared rays can be used. By providing the sensor 921, for example, data (such as temperature) indicating the environment where the power storage system is placed can be detected and stored in the memory in the circuit 912.

[0324] The storage battery and the power storage system shown in this embodiment use electrodes according to one aspect of the present invention. Therefore, the capacity of the storage battery and the power storage system can be increased. In addition, the energy density can be increased. Also, the reliability can be enhanced. Also, the lifespan can be extended.

[0325] This embodiment can be implemented in appropriate combination with other embodiments.

[0326] (Embodiment 3) ​​​​​​​In this embodiment, an example of mounting a flexible storage battery on an electronic device will be described.

[0327] An example of mounting the flexible storage battery shown in Embodiment 2 on an electronic device is shown in FIG. 23. The As an electronic device to which a storage battery having a flexible shape is applied, for example, a television set ( also referred to as a TV or a television receiver), a monitor for a computer, a digital camera, a digital video camera, a digital photo frame, a mobile phone (also referred to as a cellular phone or a mobile phone device), a portable game machine, a portable information terminal, an audio reproduction device, a pachinko machine, and other large game machines and the like can be mentioned.

[0328] In addition, it is also possible to incorporate a storage battery having a flexible shape along the inner wall or outer wall of a house or building, or along the curved surface of the interior or exterior of an automobile. It is also possible to incorporate a storage battery having a flexible shape along the inner wall or outer wall of a house or building, or along the curved surface of the interior or exterior of an automobile.

[0329] FIG. 23(A) shows an example of a mobile phone. The mobile phone 7400 includes a display unit 7402 incorporated in a housing 7401, as well as operation buttons 7403, an external connection port 7404, a speaker 7405, a microphone 7406, and the like. Note that the mobile phone 7400 has a power storage device 7407.

[0330] FIG. 23(B) shows a state in which the mobile phone 7400 is bent. When the mobile phone 740 0 is deformed by an external force and bent as a whole, the power storage device 7407 provided inside it also bends. The state of the power storage device 7407 in the bent state is shown in FIG. 23(C). The power storage device 7407 is a thin storage battery. The power storage device 7407 is fixed in a bent state Note that the power storage device 7407 is a lead electrode 740 electrically connected to a current collector 7409 It has 8. For example, the current collector 7409 is a copper foil, and a part of it is alloyed with gallium to improve the adhesion with the active material layer in contact with the current collector 7409, and the power storage device 7407 has a configuration with high reliability in a bent state.

[0331] Figure 23(D) shows an example of a bangle-type display device. The portable display device 7100 includes a housing 7101, a display unit 7102, operation buttons 7103, and a power storage device 7104. Also, FIG. 23(E) shows the state of the power storage device 7104 bent. When the power storage device 7104 is bent and worn on the user's arm, the housing deforms and the curvature of part or all of the power storage device 7104 changes. Note that the degree of bending at any point on the curve is represented by the value of the radius of the corresponding circle, which is called the radius of curvature, and the reciprocal of the radius of curvature is called the curvature. Specifically, part or all of the main surface of the housing or the power storage device 7104 changes within the range where the radius of curvature is 40 mm or more and 150 mm or less. If the radius of curvature of the main surface of the power storage device 7104 is in the range of 40 mm or more and 150 mm or less, high reliability can be maintained.

[0332] Figure 23(F) shows an example of a wristwatch-type portable information terminal. The portable information terminal 7200 includes a housing 7201, a display unit 7202, a band 7203, a buckle 7204, operation buttons 72 05, input / output terminals 7206, etc.

[0333] The portable information terminal 7200 can execute various applications such as mobile phones, e-mails, text viewing and creation, music playback, Internet communication, and computer games.

[0334] The display unit 7202 is provided with a curved display surface, and performs display along the curved display surface.​​​​​ The display portion 7202 is provided with a touch sensor, and can be used to input a touch signal to the screen using a finger or a stylus. For example, the icon 72 displayed on the display unit 7202 can be operated by touching it. You can launch the application by touching 07.

[0335] The operation button 7205 is used to set the time, turn the power on and off, and turn wireless communication on and off. It has various functions such as operation, silent mode activation and deactivation, power saving mode activation and deactivation, etc. For example, an operating system installed in the portable information terminal 7200 can The function of the operation button 7205 can also be freely set using the stem.

[0336] In addition, the mobile information terminal 7200 is capable of performing short-distance wireless communication according to a communication standard. For example, by communicating with a wireless headset, You can also make calls.

[0337] The portable information terminal 7200 also includes an input / output terminal 7206, and a connector for connecting to other information terminals. Data can be exchanged directly through the input / output terminal 7206. The charging operation can be performed by wireless power supply without going through the input / output terminal 7206. This is also possible.

[0338] The display portion 7202 of the portable information terminal 7200 includes a power storage device having an electrode according to one embodiment of the present invention. For example, the power storage device 7104 in FIG. 23E is included in a housing 7201. It can be installed in a curved state in the part of the band 7203 or in a curved state inside the band 7203. Cut.

[0339] FIG. 23(G) shows an example of a wristband-type display device. The display device 7300 has a display unit 7 304 and has a power storage device according to one aspect of the present invention. Further, the display device 7300 can also be provided with a touch sensor on the display unit 7304 and can also function as a portable information terminal .

[0340] The display surface of the display unit 7304 is curved, and display can be performed along the curved display surface . Further, the display device 7300 can change the display state by means of communication-standardized short-range wireless communication or the like .

[0341] In addition, the display device 7300 is provided with input / output terminals and can directly exchange data with other information terminals via a connector . Charging can also be performed via the input / output terminals . Note that the charging operation may be performed by wireless power supply without going through the input / output terminals

[0342] This embodiment can be implemented in appropriate combination with other embodiments

[0343] (Embodiment 4) In this embodiment, an example of an electronic device capable of mounting a power storage device is shown

[0344] FIGS. 24(A) and 24(B) show an example of a foldable tablet-type terminal. The tablet-type terminal 9600 shown in FIGS 24(A) and 24(B) includes a housing 9630a, a housing 9630b, a movable part 9640 connecting the housing 9630a and the housing 9630b, a display unit 96 31a and a display unit 9631 having a display unit 9631b, a display mode changeover switch 962 6, a power switch 9627, a power saving mode changeover switch 9625, a fastener 9629 , FIG. 24A shows the tablet terminal 9600 in an open state. 24(A) shows the tablet terminal 9600 in a closed state, and FIG. 24(B) shows the tablet terminal 9600 in a closed state.

[0345] The tablet terminal 9600 also includes a battery storage device inside the housing 9630a and the housing 9630b. The power storage unit 9635 is connected to the housing 9630a through the movable portion 9640. It is located across 9630b.

[0346] A part of the display unit 9631a can be used as a touch panel area 9632a. By touching the operation keys 9638, data can be input. In 1a, for example, half of the area has a display function, and the other half The display area has a touch panel function, but is not limited to this. The entire area of ​​9631a may have a touch panel function. The entire surface of the display unit 9631a is used as a touch panel by displaying keyboard buttons. b can be used as a display screen.

[0347] In addition, in the display unit 9631b, as in the display unit 9631a, The area 9632b of the touch panel can be used as the keyboard of the touch panel. By touching the area where the display switch button 9639 is displayed with your finger or a stylus, A keyboard button can be displayed on the display portion 9631b.

[0348] In addition, the touch panel area 9632a and the touch panel area 9632b can be touched simultaneously. You can also input the character.

[0349] In addition, the display mode switching switch 9626 can select switching the display orientation such as vertical display or horizontal display, switching between black-and-white display and color display, etc. The power saving mode switching switch 9625 can optimize the display brightness according to the amount of external light detected by the optical sensor built in the tablet terminal 9600 during use. The tablet terminal may incorporate not only an optical sensor but also other detection devices such as sensors for detecting inclination such as gyroscopes and acceleration sensors. Also, although FIG. 24(A) shows an example where the display areas of the display unit 9631b and the display unit 9631a are the same, it is not particularly limited, and the size of one display unit and the size of the other display unit may be different, and the display quality may also be different. For example, one may be a display panel capable of performing higher-definition display than the other. FIG. 24(B) shows a closed state, and the tablet terminal has a charging / discharging control circuit 9634 including a housing 9630, a solar cell 9633, and a DCDC converter 9636. Also, as the power storage body 9635, a power storage body according to one aspect of the present invention is used. Since the tablet terminal 9600 is foldable in two, it can be folded so that the housing 9630a and the housing 9630b are overlapped when not in use. By folding, the display units 9631a and 9631b can be protected, so that the durability of the tablet terminal 9600 can be enhanced. Also, the power storage body 9635 using the power storage body according to one aspect of the present invention has flexibility, and the charge / discharge capacity is less likely to decrease even when repeated bending and stretching. Therefore, a tablet terminal with excellent reliability can be provided. In addition, the display mode switching switch 9626 can select switching the display orientation such as vertical display or horizontal display, switching between black-and-white display and color display, etc. The power saving mode switching switch 9625 can optimize the display brightness according to the amount of external light detected by the optical sensor built in the tablet terminal 9600 during use. The tablet terminal may incorporate not only an optical sensor but also other detection devices such as sensors for detecting inclination such as gyroscopes and acceleration sensors. Also, although FIG. 24(A) shows an example where the display areas of the display unit 9631b and the display unit 9631a are the same, it is not particularly limited, and the size of one display unit and the size of the other display unit may be different, and the display quality may also be different. For example, one may be a display panel capable of performing higher-definition display than the other.

[0350] FIG. 24(B) shows a closed state, and the tablet terminal has a charging / discharging control circuit 9634 including a housing 9630, a solar cell 9633, and a DCDC converter 9636. Also, as the power storage body 9635, a power storage body according to one aspect of the present invention is used. Since the tablet terminal 9600 is foldable in two, it can be folded so that the housing 9630a and the housing 9630b are overlapped when not in use. By folding, the display units 9631a and 9631b can be protected, so that the durability of the tablet terminal 9600 can be enhanced. Also, the power storage body 9635 using the power storage body according to one aspect of the present invention has flexibility, and the charge / discharge capacity is less likely to decrease even when repeated bending and stretching. Therefore, a tablet terminal with excellent reliability can be provided. In addition, the display mode switching switch 9626 can select switching the display orientation such as vertical display or horizontal display, switching between black-and-white display and color display, etc. The power saving mode switching switch 9625 can optimize the display brightness according to the amount of external light detected by the optical sensor built in the tablet terminal 9600 during use. The tablet terminal may incorporate not only an optical sensor but also other detection devices such as sensors for detecting inclination such as gyroscopes and acceleration sensors. Also, although FIG. 24(A) shows an example where the display areas of the display unit 9631b and the display unit 9631a are the same, it is not particularly limited, and the size of one display unit and the size of the other display unit may be different, and the display quality may also be different. For example, one may be a display panel capable of performing higher-definition display than the other.

[0351] FIG. 24(B) shows a closed state, and the tablet terminal has a charging / discharging control circuit 9634 including a housing 9630, a solar cell 9633, and a DCDC converter 9636. Also, as the power storage body 9635, a power storage body according to one aspect of the present invention is used. Since the tablet terminal 9600 is foldable in two, it can be folded so that the housing 9630a and the housing 9630b are overlapped when not in use. By folding, the display units 9631a and 9631b can be protected, so that the durability of the tablet terminal 9600 can be enhanced. Also, the power storage body 9635 using the power storage body according to one aspect of the present invention has flexibility, and the charge / discharge capacity is less likely to decrease even when repeated bending and stretching. Therefore, a tablet terminal with excellent reliability can be provided. In addition, the display mode switching switch 9626 can select switching the display orientation such as vertical display or horizontal display, switching between black-and-white display and color display, etc. The power saving mode switching switch 9625 can optimize the display brightness according to the amount of external light detected by the optical sensor built in the tablet terminal 9600 during use. The tablet terminal may incorporate not only an optical sensor but also other detection devices such as sensors for detecting inclination such as gyroscopes and acceleration sensors.

[0352] Since the tablet terminal 9600 is foldable in two, it can be folded so that the housing 9630a and the housing 9630b are overlapped when not in use. By folding, the display units 9631a and 9631b can be protected, so that the durability of the tablet terminal 9600 can be enhanced. Also, the power storage body 9635 using the power storage body according to one aspect of the present invention has flexibility, and the charge / discharge capacity is less likely to decrease even when repeated bending and stretching. Therefore, a tablet terminal with excellent reliability can be provided. In addition, the display mode switching switch 9626 can select switching the display orientation such as vertical display or horizontal display, switching between black-and-white display and color display, etc. The power saving mode switching switch 9625 can optimize the display brightness according to the amount of external light detected by the optical sensor built in the tablet terminal 9600 during use. The tablet terminal may incorporate not only an optical sensor but also other detection devices such as sensors for detecting inclination such as gyroscopes and acceleration sensors. Since the tablet terminal 9600 is foldable in two, it can be folded so that the housing 9630a and the housing 9630b are overlapped when not in use. By folding, the display units 9631a and 9631b can be protected, so that the durability of the tablet terminal 9600 can be enhanced. Also, the power storage body 9635 using the power storage body according to one aspect of the present invention has flexibility, and the charge / discharge capacity is less likely to decrease even when repeated bending and stretching. Therefore, a tablet terminal with excellent reliability can be provided. In addition, the display mode switching switch 9626 can select switching the display orientation such as vertical display or horizontal display, switching between black-and-white display and color display, etc. The power saving mode switching switch 9625 can optimize the display brightness according to the amount of external light detected by the optical sensor built in the tablet terminal 9600 during use. The tablet terminal may incorporate not only an optical sensor but also other detection devices such as sensors for detecting inclination such as gyroscopes and acceleration sensors. Since the tablet terminal 9600 is foldable in two, it can be folded so that the housing 9630a and the housing 9630b are overlapped when not in use. By folding, the display units 9631a and 9631b can be protected, so that the durability of the tablet terminal 9600 can be enhanced. Also, the power storage body 9635 using the power storage body according to one aspect of the present invention has flexibility, and the charge / discharge capacity is less likely to decrease even when repeated bending and stretching. Therefore, a tablet terminal with excellent reliability can be provided. In addition, the display mode switching switch 9626 can select switching the display orientation such as vertical display or horizontal display, switching between black-and-white display and color display, etc. The power saving mode switching switch 9625 can optimize the display brightness according to the amount of external light detected by the optical sensor built in the tablet terminal 9600 during use. The tablet terminal may incorporate not only an optical sensor but also other detection devices such as sensors for detecting inclination such as gyroscopes and acceleration sensors.

[0353] In addition, the tablet-type terminals shown in FIGS. 24(A) and 24(B) can also have various functions such as a function to display information (still images, moving images, text images, etc.) on the display unit, a function to display a calendar, date, or time on the display unit, a touch input function to touch-input or edit the information displayed on the display unit, a function to control processing by various software (programs), etc. can have.

[0354] Power can be supplied to the touch panel, display unit, or video signal processing unit, etc. by the solar cell 9633 mounted on the surface of the tablet-type terminal. Note that the solar cell 9633 can be provided on one side or both sides of the housing 9630, and can be configured to efficiently charge the power storage body 9635. Note that when a lithium-ion battery is used as the power storage body 9635, there are advantages such as being able to achieve miniaturization.

[0355] Also, the configuration and operation of the charge / discharge control circuit 9634 shown in FIG. 24(B) will be illustrated and explained with a block diagram in FIG. 24( C). FIG. 24(C) shows the solar cell 9633, power storage body 963 5, DCDC converter 9636, converter 9637, switches SW1 to SW3, and display unit 9631, and the power storage body 9635, DCDC converter 9636, con verter 9637, and switches SW1 to SW3 correspond to the locations of the charge / discharge control circuit 96 34 shown in FIG. 24(B).

[0356] First, an example of the operation when power is generated by the solar cell 9633 due to external light will be described. The power generated by the solar cell becomes a voltage for charging the power storage body 9635 by the DCDC co ​​Voltage boosting or bucking is performed by the converter 9636. When the power from the solar cell 9633 is used for the operation of the display unit 9631, the switch SW1 is turned on, and the converter 9637 boosts or bucks the voltage to the voltage required for the display unit 9631. Also, when the display is not performed on the display unit 9631, the switch SW1 is turned off and the switch SW2 is turned on to charge the capacitor 9635.

[0357] Note that the solar cell 9633 is shown as an example of the power generation means, but is not particularly limited, and the capacitor 9635 may be charged by other power generation means such as a piezoelectric element (piezo element) or a thermoelectric conversion element (Peltier element). For example, a contactless power transmission module that charges by wireless (non-contact) power transmission and reception, or a configuration that combines other charging means may be used.

[0358] Fig. 25 shows an example of another electronic device. In Fig. 25, the display device 8000 is an example of an electronic device using the power storage device 8004 according to one aspect of the present invention. Specifically, the display device 800 0 corresponds to a display device for receiving TV broadcasts, and includes a housing 8001, a display unit 8002, a speaker unit 8003, a power storage device 8004, etc. The power storage device 8004 according to one aspect of the present invention is provided inside the housing 8001. The display device 8000 can be supplied with power from a commercial power source, or can use the power stored in the power storage device 8004. Therefore, even when power supply from a commercial power source cannot be received due to a power

[0359] The display unit 8002 includes a light-emitting element such as a liquid crystal display device or an organic EL element in each pixel. Devices, electrophoretic display devices, DMD (Digital Micromirror Devi ce), PDP (Plasma Display Panel), FED (Field Emission Display), etc., can use a semiconductor display device.

[0360] In addition to being used for receiving TV broadcasts, the display device also includes display devices for personal computers, advertising displays, etc. All display devices for information display are included.

[0361] In FIG. 25, the installed lighting device 8100 is an example of an electronic device using the power storage device 81 03 according to one aspect of the present invention. Specifically, the lighting device 8100 includes a housing 8101, a light source 8102, a power storage device 8103, etc. In FIG. 25, the case where the power storage device 8103 is provided inside the ceiling 81 01 and the light source 8102 are installed is illustrated However, the power storage device 8103 may be provided inside the housing 8101. The lighting device 8100 can receive power supply from a commercial power source, or can use the power stored in the power storage device 8103. Therefore, even when the power supply from the commercial power source cannot be received due to a power outage or the like, by using the power storage device 8103 according to one aspect of the present invention as an uninterruptible power supply, the lighting device 8100 can be used. In FIG. 25, the installed lighting device 8100 provided on the ceiling 8104 is illustrated

[0362] However, although the installed lighting device 8100 provided on the ceiling 8104 is illustrated in FIG. 25, the power storage device according to one aspect of the present invention can also be used for installed lighting devices provided on, for example, side walls 8105, floors 8 106, windows 8107, etc., other than the ceiling 8104, and can also be used for desktop It can also be used in lighting devices of this type, etc.

[0363] Moreover, as the light source 8102, an artificial light source that artificially obtains light using electric power can be used. Specifically, incandescent bulbs, discharge lamps such as fluorescent lamps, and light-emitting elements such as LEDs and organic EL elements can be cited as examples of the above artificial light sources.

[0364] In FIG. 25, an air conditioner having an indoor unit 8200 and an outdoor unit 8204 is an example of an electronic device using a power storage device 8203 according to one aspect of the present invention. Specifically, the indoor unit 8200 has a housing 8201, an air outlet 8202, a power storage device 8203, etc. FIG. 25 illustrates the case where the power storage device 8203 is provided in the indoor unit 8200, but the power storage device 8203 may be provided in the outdoor unit 8204. Alternatively, the power storage device 8203 may be provided in both the indoor unit 8200 and the outdoor unit 8204. The air conditioner can receive power supply from a commercial power source or use the power stored in the power storage device 8203. In particular, when the power storage device 8203 is provided in both the indoor unit 8200 and the outdoor unit 8204, even when power supply from the commercial power source cannot be received due to a power outage or the like, by using the power storage device 8203 according to one aspect of the present invention as an uninterruptible power supply, the air conditioner can be used.

[0365] Note that in FIG. 25, a separate type of air conditioner composed of an indoor unit and an outdoor unit is illustrated, but a power storage device according to one aspect of the present invention can also be used in an integrated type of air conditioner having the functions of the indoor unit and the outdoor unit in one housing.

[0366] ​​​​​​​​​​​​​In FIG. 25, an electric refrigerator 8300 is an example of an electronic device using a power storage device 8304 according to one aspect of the present invention. Specifically, the electric refrigerator 8300 includes a housing 8301, a door 8302 for a refrigerating compartment, a door 8303 for a freezing compartment, a power storage device 8304, and the like. In FIG. 25, the power storage device 8304 is provided inside the housing 8301. The electric refrigerator 8300 can receive power supply from a commercial power source or use the power stored in the power storage device 8304. Therefore, even when power supply from the commercial power source cannot be received due to a power outage or the like, by using the power storage device 8304 according to one aspect of the present invention as an uninterruptible power supply, the electric refrigerator 8300 can be used. Among the above-described electronic devices, high-frequency heating devices such as microwave ovens and electronic devices such as electric rice cookers require high power in a short time. Therefore, by using a power storage device according to one aspect of the present invention as an auxiliary power supply to supplement power that cannot be covered by the commercial power source, it is possible to prevent the breaker of the commercial power source from tripping during the use of the electronic device. In addition, during a time period when the electronic device is not in use, particularly during a time period when the ratio of the actually used power amount to the total power amount that can be supplied by the commercial power source (referred to as the power utilization rate) is low, by storing power in the power storage device, it is possible to suppress an increase in the power utilization rate outside the above time period. For example, in the case of the electric refrigerator 8300, at night when the temperature is low and the doors 8302 and 8303 of the refrigerating compartment and the freezing compartment are not opened or closed, power is stored in the power storage device 8304. Then, when the temperature rises and the doors 8302 and 8303 of the refrigerating compartment and the freezing compartment are opened or closed,

[0367]

[0368] ​​​​​​​​​​​​​​​During the daytime, by using the power storage device 8304 as an auxiliary power source, the daytime power utilization rate can be kept low.

[0369] This embodiment can be implemented in appropriate combination with other embodiments.

[0370] (Embodiment 5) In this embodiment, an example of mounting a power storage device on a vehicle is shown.

[0371] Also, when a power storage device is mounted on a vehicle, next-generation clean energy vehicles such as hybrid electric vehicles (HEVs), electric vehicles (EVs), or plug-in hybrid electric vehicles (PHEVs) can be realized. It can be done.

[0372] In FIG. 26, a vehicle using one aspect of the present invention is illustrated. The automobile 8 400 shown in FIG. 26(A) is an electric vehicle that uses an electric motor as a power source for running. Or, it is a hybrid vehicle that can appropriately select and use an electric motor and an engine as power sources for running. By using one aspect of the present invention, a vehicle with a long cruising range can be realized. Also, the automobile 8400 has a power storage device. The power storage device not only drives the electric motor 8 406, but can also supply power to light-emitting devices such as a headlight 8401 and a room light (not shown). It can supply power to the light-emitting device.

[0373] In addition, the power storage device can supply power to display devices such as a speedometer and a tachometer that the automobile 8400 has. Also, the power storage device can supply power to semiconductor devices such as a navigation system that the automobile 8400 has. It can supply power to the semiconductor device.

[0374] The motor vehicle 8500 shown in Fig. 26(B) can be charged by receiving power supply from an external charging facility by means of a plug-in method, a non-contact power supply method, or the like, from the power storage device of the motor vehicle 8500. Fig. 26(B) shows a state in which charging is being performed from a ground-installed charging device 8021 to a power storage device 8024 mounted on a motor vehicle 8500 via a cable 8022. When charging, the charging method, the connector specifications, etc. may be appropriately carried out in a predetermined manner such as CHAdeMO (registered trademark) or Combo. The charging device 8021 may be a charging station provided in a commercial facility, or may also be a household power source. For example, by means of plug-in technology, the power storage device 8024 mounted on the motor vehicle 8500 can be charged by external power supply. Charging can be performed by converting AC power into DC power via a conversion device such as an AC / DC converter.

[0375] Although not shown, a power receiving device can be mounted on the vehicle, and power can be supplied non-contact from a power transmitting device on the ground for charging. In the case of this non-contact power supply method, by incorporating a power transmitting device into a road or an outer wall, charging can be performed not only while the vehicle is stopped but also while it is running. Also, using this non-contact power supply method, power can be transmitted and received between vehicles. Furthermore, a solar cell can be provided on the exterior of the vehicle to charge the power storage device when the vehicle is stopped or running. For such non-contact power supply, an electromagnetic induction method or a magnetic field resonance method can be used.

[0376] According to one aspect of the present invention, the cycle characteristics of the power storage device can be improved, and the reliability can be enhanced. Also, according to one aspect of the present invention, the characteristics of the power storage device can be improved, and ​​​​​​Thus, the storage device itself can be made smaller and lighter. If the storage device itself can be made smaller and lighter, it contributes to the weight reduction of the vehicle, so that the cruising range can be improved. In addition, the storage device mounted on the vehicle can also be used as a power supply source other than the vehicle. In this case, it is possible to avoid using the commercial power supply at the peak of the power demand.

[0377] This embodiment can be implemented in appropriate combination with other embodiments.

[0378] (Embodiment 6) A battery control unit (Battery Management Unit: BMU) that can be used in combination with a battery cell including the material described in the above embodiment, and a transistor suitable for the circuit constituting the battery control unit will be described with reference to FIGS. 27 to 33. In this embodiment, the battery control unit of a storage device having battery cells connected in series will be particularly described.

[0379] When charging and discharging are repeatedly performed on a plurality of battery cells connected in series, variations occur in the charge and discharge characteristics among the battery cells, and the capacities (output voltages) of the battery cells become different. In a plurality of battery cells connected in series, the overall capacity during discharge depends on the battery cell with the smallest capacity. If there are variations in the capacities of the battery cells, the overall capacity during discharge becomes smaller. Also, if charging is performed based on the battery cell with the smallest capacity,

[0380] there is a risk of undercharging. Also, if charging is performed based on the battery cell with the It also has a function of equalizing the capacity variations between battery cells, which are the cause of overcharging. Battery cells Circuit configurations for equalizing the capacity variations between battery cells include a resistance method, a capacitor method, an inductor method, etc. Here, as an example, a circuit configuration capable of equalizing the capacity variations by using a transistor with a small off-current will be described. As the transistor with a small off-current, a transistor having an oxide semiconductor in the channel formation region (OS transistor) is preferable. By using an OS transistor with a small off-current in the circuit configuration of the battery control unit of the power storage device, the amount of charge leaked from the battery cells can be reduced, and the decrease in capacity over time can be suppressed.

[0381] For the oxide semiconductor used in the channel formation region, In-M-Zn oxide (M is Ga, Sn, Y, Zr, La, Ce, or Nd) is used. In the target used for forming the oxide semiconductor film, when the atomic ratio of the metal elements is In:M:Zn = x1:y1:z1, x1 / y1 is 1 / 3 or more and 6 or less, further 1 or more and 6 or less, and z1 / y1 is 1 / 3 or more and 6 or less, further 1 or more and 6 or less. By setting z1 / y1 to 1 or more and 6 or less, it becomes easier to form a CAAC-OS film as the oxide semiconductor film.

[0382] Here, the CAAC-OS film will be described. The CAAC-OS film is one of the oxide semiconductor films having a plurality of c-axis oriented crystal parts. The bright-field image and diffraction pattern of the CAAC-OS film are obtained by a transmission electron microscope (TEM). 、 x1 / y1 is 1 / 3 or more and 6 or less, further 1 or more and 6 or less, and z1 / y1 is 1 / 3 or more and 6 or less, further 1 or more and 6 or less. By setting z1 / y1 to 1 or more and 6 or less, it becomes easier to form a CAAC-OS film as the oxide semiconductor film. Here, the CAAC-OS film will be described.

[0383] Here, the CAAC-OS film will be described.

[0384] The CAAC-OS film is one of the oxide semiconductor films having a plurality of c-axis oriented crystal parts.

[0385] The bright-field image and diffraction pattern of the CAAC-OS film are obtained by a transmission electron microscope (TEM). By observing the composite analysis image (also referred to as a high-resolution TEM image), a plurality of crystal portions can be confirmed. On the other hand, the boundaries between distinct crystal portions, i.e., crystal grain boundaries (also referred to as grain boundaries), cannot be confirmed by high-resolution TEM images. Therefore, it can be said that in the CAAC -OS film, a decrease in electron mobility due to crystal grain boundaries is less likely to occur.

[0386] When observing the high-resolution TEM image of the cross-section of the CAAC-OS film from a direction substantially parallel to the sample surface, it can be confirmed that metal atoms are arranged in layers in the crystal portion. Each layer of metal atoms has a shape that reflects the unevenness of the surface (also referred to as the surface to be formed) or the upper surface of the CAAC-OS film, and is arranged parallel to the surface to be formed or the upper surface of the CAAC-OS film.

[0387] On the other hand, when observing the high-resolution TEM image of the plane of the CAAC-OS film from a direction substantially perpendicular to the sample surface, it can be confirmed that metal atoms are arranged in a triangular or hexagonal shape in the crystal portion. However, no regularity is observed in the arrangement of metal atoms between different crystal portions.

[0388] When performing structural analysis on the CAAC-OS film using an X-ray diffraction (XRD) apparatus, for example, in the out-of-plane method analysis of a CAAC-OS film having In nGaZnO4 crystals, a peak may appear near a diffraction angle (2θ) of 31°. Since this peak is attributed to the (009) plane of the In GaZnO4 crystal, it can be confirmed that the crystal of the CAAC-OS film has a c axis orientation, and the c axis is oriented in a direction substantially perpendicular to the surface to be formed or the upper surface.

[0389] Note that in the out-of-plane method of the CAAC-OS film having InGaZnO4 crystals In the analysis by , in addition to the peak where 2θ is near 31°, a peak may also appear where 2θ is near 36°. The peak where 2θ is near 36° indicates that a part of the CAAC-OS film contains crystals that do not have c-axis orientation. The CAAC-OS film preferably shows a peak where 2θ is near 31° and does not show a peak where 2θ is near 36°.

[0390] The CAAC-OS film is an oxide semiconductor film with a low impurity concentration. Impurities are elements other than the main components of the oxide semiconductor film, such as hydrogen, carbon, silicon, and transition metal elements. In particular, elements with a stronger binding force with oxygen than the metal elements constituting the oxide semiconductor film, such as silicon, will disrupt the atomic arrangement of the oxide semiconductor film by taking oxygen from the oxide semiconductor film, leading to a decrease in crystallinity. Also, heavy metals such as iron and nickel, argon, carbon dioxide, etc., have a large atomic radius (or molecular radius), so when they are contained inside the oxide semiconductor film, they will disrupt the atomic arrangement of the oxide semiconductor film and lead to a decrease in crystallinity. Note that impurities contained in the oxide semiconductor film may become carrier traps or carrier generation sources.

[0391] Moreover, the CAAC-OS film is an oxide semiconductor film with a low defect level density. For example, oxygen deficiencies in the oxide semiconductor film may become carrier traps or carrier generation sources by capturing hydrogen.

[0392] A low impurity concentration and a low defect level density (few oxygen deficiencies) are referred to as high-purity intrinsic or substantially high-purity intrinsic. An oxide semiconductor film that is high-purity intrinsic or substantially high-purity intrinsic has few carrier generation sources, so the carrier density can be lowered. Therefore, A transistor using the oxide semiconductor film rarely has electrical characteristics in which the threshold voltage becomes negative ( also referred to as normally-on).) Also, an oxide semiconductor film having high-purity intrinsic or substantially high-purity intrinsic has few carrier traps. Therefore, a transistor using the oxide semiconductor film has small fluctuations in electrical characteristics and becomes a highly reliable transistor. Note that the charge trapped in the carrier trap of the oxide semiconductor film takes a long time to be released and may behave like a fixed charge. Therefore, a transistor using an oxide semiconductor film with a high impurity concentration and a high defect level density may have unstable electrical characteristics.

[0393] Also, a transistor using a CAAC-OS film has small fluctuations in electrical characteristics due to irradiation with visible light or ultraviolet light.

[0394] Note that an OS transistor has a larger bandgap than a transistor having silicon in the channel formation region (Si transistor), so breakdown is less likely to occur when a high voltage is applied. When battery cells are connected in series, a voltage of several hundred volts will occur, but for the circuit configuration of a battery control unit applied to such battery cells in a power storage device, it is suitable to be composed of the aforementioned OS transistors.

[0395] FIG. 27 shows an example of a block diagram of a power storage device. The power storage device BT00 shown in FIG. 27 includes a terminal pair BT01, a terminal pair BT02, a switching control circuit BT03, a switching circuit BT0 4, a switching circuit BT05, a voltage control circuit BT06, a voltage circuit BT07, and a battery unit BT08 including a plurality of battery cells BT09 connected in series. ​​​​​​​​​

[0396] Also, in the power storage device BT00 of FIG. 27, the part composed of the terminal pair BT01, the terminal pair BT02, the switching control circuit BT03, the switching circuit BT04, the switching circuit BT05, the voltage control circuit BT06, and the voltage conversion circuit BT07 can be called a battery control unit. The switching control circuit BT03 controls the operations of the switching circuit BT04 and the switching circuit BT05. Specifically, the switching control circuit BT03 determines the battery cells to be discharged (discharge battery cell group) and the battery cells to be charged (charge battery cell group) based on the voltage measured for each battery cell BT09. Furthermore, the switching control circuit BT03 outputs a control signal S1 and a control signal S2 based on the determined discharge battery cell group and charge battery cell group. The control signal S1 is output to the switching circuit BT04. This control signal S1 is a signal for controlling the switching circuit BT04 to connect the terminal pair BT01 and the discharge battery cell group. Also, the control signal S2 is output to the switching circuit BT05. This control signal S2 is a signal for controlling the switching circuit BT05 to connect the terminal pair BT02 and the charge battery cell group.

[0397] In addition, the switching control circuit BT03 generates the control signal S1 and the control signal S2 so that terminals of the same polarity are connected between the terminal pair BT01 and the discharge battery cell group or between the terminal pair BT02 and the charge battery cell group, taking into account the configurations of the switching circuit BT04, the switching circuit BT05, and the voltage conversion circuit BT07.

[0398]

[0399]

[0400] ​​​​​​​​​​​​​​The operation of the switching control circuit BT03 will now be described in detail.

[0401] First, the switching control circuit BT03 measures the voltage of each of the multiple battery cells BT09. The switching control circuit BT03 then selects, for example, the battery cell BT09 having a voltage equal to or higher than a predetermined threshold. High voltage battery cells (high voltage cells), battery cells BT09 with voltages below a certain threshold are classified as low voltage It is determined to be a battery cell (low voltage cell).

[0402] There are various methods for determining whether a cell is a high-voltage cell or a low-voltage cell. For example, the switching control circuit BT03 selects the most highly charged battery cell BT09 from among multiple battery cells. The voltage of each battery cell BT0 is set based on the voltage of the battery cell BT09 with the highest or lowest voltage. 9 may be determined to be a high-voltage cell or a low-voltage cell. In this case, the switching control circuit BT03 determines whether the voltage of each battery cell BT09 is equal to or greater than a predetermined ratio 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, the switching control circuit BT03 switches between the discharging battery cell group and the charging battery cell group based on the result of this judgment. The pond cell group is determined.

[0403] In addition, among the multiple battery cells BT09, high voltage cells and low voltage cells are mixed in various states. For example, the switching control circuit BT03 can select the voltage between high-voltage cells and low-voltage cells. The part with the largest number of high-voltage cells connected in series is the discharge battery cell group. The switching control circuit BT03 charges the part with the most low-voltage cells connected in series. The switching control circuit BT03 detects battery cells that are close to being overcharged or overdischarged. It is also possible to preferentially select the BT09 as a discharging battery cell group or a charging battery cell group. This is acceptable.

[0404] Here, an operation example of the switching control circuit BT03 in the present embodiment will be described with reference to FIG. 28. FIG. 28 is a diagram for explaining an operation example of the switching control circuit BT03. For the sake of convenience of explanation, in FIG. 28, a case where four battery cells BT09 are connected in series will be described as an example. For the sake of convenience of explanation, in FIG. 28, a case where four battery cells BT09 are connected in series will be described as an example. will be described.

[0405] First, in the example of FIG. 28(A), assuming that the voltages of battery cells BT09 from a to d are voltage Va to voltage Vd, it shows a case where Va = Vb = Vc > Vd. That is, three consecutive high-voltage cells a to c and one low-voltage cell d are connected in series. In this case, the switching control circuit BT03 determines the three consecutive high-voltage cells a to c as the discharging battery cell group. Also, the switching control circuit BT03 determines the low-voltage cell d as the charging battery cell group. d, it shows a case where Va = Vb = Vc > Vd. That is, three consecutive high-voltage cells a to c and one low-voltage cell d are connected in series. In this case, the switching control circuit BT03 determines the three consecutive high-voltage cells a to c as the discharging battery cell group. Also, the switching control circuit BT03 determines the low-voltage cell d as the charging battery cell group. will be described. will be described. will be described. will be described.

[0406] Next, in the example of FIG. 28(B), it shows a case where Vc > Va = Vb >> Vd. That is, two consecutive low-voltage cells a, b, one high-voltage cell c, and one low-voltage cell d near over-discharge are connected in series. In this case, the switching control circuit BT03 determines the high-voltage cell c as the discharging battery cell group. Also, since the low-voltage cell d is near over-discharge, the switching control circuit BT03 preferentially determines the low-voltage cell d as the charging battery cell group instead of the two consecutive low-voltage cells a and b. will be described. will be described. will be described. will be described. will be described.

[0407] Finally, in the example of FIG. 28(C), it shows a case where Va > Vb = Vc = Vd. That is, one high-voltage cell a and three consecutive low-voltage cells b to d are connected in series. In this case, the switching control circuit BT03 determines the high-voltage cell a as the discharge battery cell group. Also, the switching control circuit BT03 determines the three consecutive low-voltage cells b to d as the charge battery cell group.

[0408] Based on the determined result as in the examples of FIGS. 28(A) to (C) above, the switching control circuit BT03 sets the control signal S1 indicating the discharge battery cell group which is the connection destination of the switching circuit BT04, and the control signal S2 indicating the charge battery cell group which is the connection destination of the switching circuit BT05, and outputs them to the switching circuit BT04 and the switching circuit BT05 respectively.

[0409] The above is the detailed description of the operation of the switching control circuit BT03.

[0410] The switching circuit BT04 sets the connection destination of the terminal pair BT01 to the discharge battery cell group determined by the switching control circuit BT03 according to the control signal S1 output from the switching control circuit BT03.

[0411] The terminal pair BT01 is composed of the paired terminals A1 and A2. The switching circuit BT04 connects one of the terminals A1 and A2 to the positive terminal of the battery cell BT09 located most upstream (high potential side) in the discharge battery cell group, and the other to the negative terminal of the battery cell BT09 located most downstream (low potential side) in the discharge battery cell group, thereby setting the connection destination of the terminal pair BT01. Note that the switching circuit BT04 can recognize the position of the discharge battery cell group using the information set in the control signal S1.

[0412] The switching circuit BT05, according to the control signal S2 output from the switching control circuit BT03, sets the connection destination of the terminal pair BT02 to the rechargeable battery cell group determined by the switching control circuit BT03.

[0413] The terminal pair BT02 is composed of paired terminals B1 and B2. The switching circuit BT05 connects one of the terminals B1 and B2 to the positive terminal of the battery cell BT09 located most upstream (higher potential side) in the rechargeable battery cell group, and the other to the negative terminal of the battery cell BT09 located most downstream (lower potential side) in the rechargeable battery cell group, thereby setting the connection destination of the terminal pair BT02. Note that the switching circuit BT05 can recognize the position of the rechargeable

[0414] circuit diagrams showing configuration examples of the switching circuit BT04 and the switching circuit BT05 are shown in FIGS. 29 and 30.

[0415] In FIG. 29, the switching circuit BT04 has a plurality of transistors BT10, and buses BT11 and BT12. The bus BT11 is connected to the terminal A1. Also, the bus BT1 2 is connected to the terminal A2. One of the sources or drains of the plurality of transistors BT10 is alternately connected to the buses BT11 and BT12 every other one. Also the other of the sources or drains of the plurality of transistors BT10 is connected between every two adjacent battery cells BT09.

[0416] Among the plurality of transistors BT10, the source of the transistor BT10 located most upstream The other of the source or drain is connected to the positive electrode terminal of the battery cell BT09 located at the most upstream of the battery unit BT08. Among the plurality of transistors BT10, the other of the source or drain of the transistor BT10 located at the most downstream is connected to the negative electrode terminal of the battery cell BT09 located at the most downstream of the battery unit BT08.

[0417] The switching circuit BT04, according to the control signal S1 applied to the gates of the plurality of transistors BT10, conducts one of the plurality of transistors BT10 connected to the bus BT11 and one of the plurality of transistors BT10 connected to the bus BT12, respectively, to connect the discharge battery cell group and the terminal pair BT01. As a result, the positive electrode terminal of the battery cell BT09 located most upstream in the discharge battery cell group is connected to either one of the terminals A1 or A2 of the terminal pair. Also, the negative electrode terminal of the battery cell BT09 located most downstream in the discharge battery cell group is connected to the other of the terminals A1 or A2 of the terminal pair, that is, the terminal not connected to the positive electrode terminal.

[0418] It is preferable to use an OS transistor for the transistor BT10. Since the OS transistor has a small off-current, it can reduce the amount of charge leaking from the battery cells not belonging to the discharge battery cell group and suppress the decrease in capacity over time. Also, the OS transistor is less likely to suffer dielectric breakdown when a high voltage is applied. Therefore, even when the output voltage of the discharge battery cell group is large, the battery cell BT09 and the terminal pair BT01 to which the non-conducting transistor BT10 is connected can be kept in an insulated state.

[0419] ​​​​​​​​​​​Also, in FIG. 29, the switching circuit BT05 includes a plurality of transistors BT13, a current control switch BT14, a bus BT15, and a bus BT16. The buses BT15 and BT 16 are arranged between the plurality of transistors BT13 and the current control switch BT14. One of the sources or drains of the plurality of transistors BT13 is alternately connected to the buses BT15 and BT16 every other one. Also, the other of the sources or drains of the plurality of transistors BT13 is connected between two adjacent battery cells BT09.

[0420] Among the plurality of transistors BT13, the other of the source or drain of the transistor BT13 located most upstream is connected to the positive terminal of the battery cell BT09 located most upstream in the battery unit BT08. Also, among the plurality of transistors BT13, the other of the source or drain of the transistor BT13 located most downstream is connected to the negative terminal of the battery cell BT09 located most downstream in the battery unit BT08.

[0421] Similar to the transistor BT10, it is preferable to use an OS transistor for the transistor BT13. Since the OS transistor has a small off-current, it can reduce the amount of charge leaking from battery cells that do not belong to the rechargeable battery cell group and suppress the capacity reduction over time. Also, the OS transistor is less likely to suffer dielectric breakdown when a high voltage is applied. Therefore, even if the voltage for charging the rechargeable battery cell group is large, the battery cell BT09 and the terminal pair BT02 to which the non-conducting transistor BT 13 is connected can be insulated. 13 is connected can be insulated.

[0422] The current control switch BT14 has a switch pair BT17 and a switch pair BT18. The one end of the switch pair BT17 is connected to the terminal B1. Also, the other end of the switch pair BT17 branches out with two switches, one switch is connected to the bus BT15, and the other switch is connected to the bus BT16. One end of the switch pair BT18 is connected to the terminal B2. Also, the other end of the switch pair BT18 branches out with two switches, one switch is connected to the bus BT15, and the other switch is connected to the bus BT16. .

[0423] The switches of the switch pair BT17 and the switch pair BT18 preferably use OS transistors, similar to the transistor BT10 and the transistor BT13.

[0424] The switching circuit BT05 controls the combination of the on / off states of the transistor BT13 and the current control switch BT14 according to the control signal S2, thereby connecting the rechargeable battery cell group to the terminal pair BT02.

[0425] The switching circuit BT05, as an example, connects the rechargeable battery cell group to the terminal pair BT0 2 as follows.

[0426] The switching circuit BT05 makes the transistor BT13 connected to the positive terminal of the battery cell BT09, which is located most upstream in the rechargeable battery cell group, conductive according to the control signal S2 applied to the gates of the plurality of transistors BT13. Also, the switching circuit BT05 makes the transistor BT13 connected to the negative terminal of the battery cell BT09, which is located most downstream in the rechargeable battery cell group, conductive according to the control signal S2 applied to the gates of the plurality of transistors BT13 . And, the switching circuit BT05, according to the control signal S2 applied to the gates of the plurality of transistors BT13, connects the rechargeable battery cell group to the terminal pair BT02. connected to the negative terminal of the battery cell BT09. Set it to the conducting state.

[0427] The polarity of the voltage applied to the terminal pair BT02 can vary depending on the discharge battery cell group connected to the terminal pair BT01 , and the configuration of the transformer circuit BT07. Also, in order to flow a current in the direction of charging the rechargeable battery cell group, it is necessary to connect terminals of the same polarity between the terminal pair BT02 and the rechargeable battery cell group to each other. Therefore, the current control switch BT14 is controlled by the control signal S2 to switch the connection destinations of the switch pair BT17 and the switch pair BT 18 according to the polarity of the voltage applied to the terminal pair BT02, respectively.

[0428] As an example, a state will be described in which a voltage such that terminal B1 is the positive electrode and terminal B2 is the negative electrode is applied to the terminal pair BT02. At this time, when the battery cell BT09 at the most downstream of the battery unit BT08 is the rechargeable battery cell group, the switch pair BT17 is controlled by the control signal S2 to be connected to the positive electrode terminal of the battery cell BT09. That is, the switch connected to the bus BT16 of the switch pair BT17 is turned on, and the switch connected to the bus BT1 5 of the switch pair BT17 is turned off. On the other hand, the switch pair BT18 is controlled by the control signal S2 to be connected to the negative electrode terminal of the battery cell BT09. That is, the switch connected to the bus BT15 of the switch pair BT18 is turned on, and the switch connected to the bus BT1 6 of the switch pair BT18 is turned off. In this way, terminals of the same polarity are connected between the terminal pair BT02 and the rechargeable battery cell group. And the direction of the current flowing from the terminal pair BT02 is controlled to be in the direction of charging the rechargeable battery cell group.

[0429] Also, the current control switch BT14 may be included in the switching circuit BT04 instead of the switching circuit BT05.

[0430] FIG. 30 is a circuit diagram showing a configuration example of the switching circuit BT04 and the switching circuit BT05, which is different from FIG. 29.

[0431] In FIG. 30, the switching circuit BT04 has a plurality of transistor pairs BT21, a bus BT24, and a bus BT25. The bus BT24 is connected to the terminal A1. Also, the bus BT25 is connected to the terminal A2. One end of each of the plurality of transistor pairs BT21 branches into a transistor BT22 and a transistor BT23, respectively. One of the source or drain of the transistor BT22 is connected to the bus BT24. Also, one of the source or drain of the transistor BT23 is connected to the bus BT25. Also, the other ends of the plurality of transistor pairs BT21 are connected between two adjacent battery cells BT09, respectively. Note that, among the plurality of transistor pairs BT21, the other end of the transistor pair BT21 located at the most upstream is connected to the positive terminal of the battery cell BT09 located at the most upstream of the battery unit BT08. Also, among the plurality of transistor pairs BT21, the other end of the transistor pair BT21 located at the most downstream is connected to the negative terminal of the battery cell BT09 located at the most downstream of the battery unit BT08.

[0432] The switching circuit BT04 switches the conduction / non-conduction states of the transistor BT22 and the transistor BT23 according to the control signal S1, thereby switching the connection destination of the transistor pair BT21 to either the terminal A1 or the terminal A2. Specifically, the transistor B ​​​​​​​ If T22 is conductive, transistor BT23 is non-conductive and is connected to terminal On the other hand, if the transistor BT23 is in a conductive state, the transistor BT22 The transistors BT22 and BT23 are non-conductive and connected to the terminal A2. Which of the transistors BT23 is turned on is determined by a control signal S1.

[0433] Two transistor pairs BT21 are used to connect the terminal pair BT01 to the discharge battery cell group. In detail, the connection destination of the two transistor pairs BT21 is determined based on the control signal S1. are determined, the discharge battery cell group and the terminal pair BT01 are connected. One of the transistor pairs BT21 is connected to the terminal A1, and the other is connected to the terminal A2 by the control signal S1.

[0434] The switching circuit BT05 includes a plurality of transistor pairs BT31, a bus BT34, and a bus BT The bus BT34 is connected to the terminal B1. The bus BT35 includes: One end of each of the transistor pairs BT31 is connected to the terminal B2. The transistor BT32 branches off the transistor BT33. One end of the branched signal is connected to a bus BT34. One of the branched ends is connected to a bus BT35. The other ends of the BT09 are connected between two adjacent battery cells BT09. The other end of the transistor pair BT31 located at the most upstream of the transistor pairs BT31 is It is connected to the positive terminal of the battery cell BT09 located at the most upstream of the battery unit BT08. Among the plurality of transistor pairs BT31, the other end of the transistor pair BT31 located most downstream is connected to the negative terminal of the battery cell BT09 located most downstream of the battery unit BT08. The other end of the transistor pair BT31 located most downstream is connected to the negative terminal of the battery cell BT09 located most downstream of the battery unit BT08. .

[0435] The switching circuit BT05 switches the conduction / non-conduction states of the transistor BT32 and the transistor BT33 to switch the connection destination of the transistor pair BT31 to either the terminal B1 or the terminal B2. Specifically, if the transistor BT32 is in the conduction state, the transistor BT33 is in the non-conduction state, and its connection destination is the terminal B1. Conversely, if the transistor BT33 is in the conduction state, the transistor BT32 is in the non-conduction state, and its connection destination is the terminal B2. Whether the transistor BT32 or the transistor BT33 is in the conduction state is determined by the control signal S2. Whether the transistor BT32 or the transistor

[0436] To connect the terminal pair BT02 and the rechargeable battery cell group, two transistor pairs BT31 are used. Specifically, based on the control signal S2, the connection destinations of the two transistor pairs BT31 are respectively determined, whereby the rechargeable battery cell group and the terminal pair BT02 are connected. The connection destination of each of the two transistor pairs BT31 is controlled by the control signal S2 such that one becomes the terminal B1 and the other becomes the terminal B2. The connection destinations of each of the two transistor pairs BT31 are determined by the polarity of the voltage applied to the terminal pair BT02. Specifically, when a voltage such that the terminal B1 is the positive electrode and the terminal B2 is the negative electrode is applied to the terminal pair BT02, the upstream transistor pair BT31 is

[0437] Also, the connection destinations of each of the two transistor pairs BT31 are determined by the polarity of the voltage applied to the terminal pair BT02. Specifically, when a voltage such that the terminal B1 is the positive electrode and the terminal B2 is the negative electrode is applied to the terminal pair BT02, the upstream transistor pair BT31 is When a voltage such that the terminal B1 is the positive electrode and the terminal B2 is the negative electrode is applied to the terminal pair BT02, the upstream transistor pair BT31 , the transistor BT32 is turned on and the transistor BT33 is turned off, and it is controlled by the control signal S2. On the other hand, the downstream transistor pair BT31 is controlled by the control signal S2 so that the transistor BT33 is turned on and the transistor BT32 is turned off. Also, when a voltage such that terminal B1 is the negative electrode and terminal B2 is the positive electrode is applied to the terminal pair BT02, the upstream transistor pair BT31 is controlled by the control signal S2 so that the transistor BT33 is turned on and the transistor BT32 is turned off. On the other hand, the downstream transistor pair BT31 is controlled by the control signal S2 so that the transistor BT32 is turned on and the transistor BT33 is turned off. In this way, terminals with the same polarity are connected between the terminal pair BT02 and the rechargeable battery cell group. And the direction of the current flowing from the terminal pair BT02 is controlled to be in the direction of charging the rechargeable battery cell group. Thus, it is controlled by the control signal S2. The transistor BT33 is turned on and the transistor BT32 is turned off. Also, when a voltage such that terminal B1 is the negative electrode and terminal B2 is the positive electrode is applied to the terminal pair BT02, the upstream transistor pair BT31 is controlled by the control signal S2 so that the transistor BT33 is turned on and the transistor BT32 is turned off. On the other hand, the downstream transistor pair BT31 is controlled by the control signal S2 so that the transistor BT32 is turned on and the transistor BT33 is turned off. The transistor BT33 is turned on and the transistor BT32 is turned off. Thus, it is controlled by the control signal S2. On the other hand, the downstream transistor pair BT31 is controlled by the control signal S2 so that the transistor BT32 is turned on and the transistor BT33 is turned off. In this way, terminals with the same polarity are connected between the terminal pair BT02 and the rechargeable battery cell group. And the direction of the current flowing from the terminal pair BT02 is controlled to be in the direction of charging the rechargeable battery cell group.

[0438] The voltage control circuit BT06 controls the operation of the voltage circuit BT07. The voltage control circuit BT06 generates a voltage control signal S3 for controlling the operation of the voltage circuit BT07 based on the number of battery cells BT09 included in the discharge battery cell group and the number of battery cells BT09 included in the rechargeable battery cell group, and outputs it to the voltage circuit BT07. The number of battery cells BT09 included in the discharge battery cell group and the number of battery cells BT09 included in the rechargeable battery cell group. Generates a voltage control signal S3 for controlling the operation of the voltage circuit BT07 based on the number of battery cells BT09 included in the discharge battery cell group and the number of battery cells BT09 included in the rechargeable battery cell group, and outputs it to the voltage circuit BT07.

[0439] Note that when the number of battery cells BT09 included in the discharge battery cell group is larger than the number of battery cells BT09 included in the rechargeable battery cell group, it is necessary to prevent an excessive charging voltage from being applied to the rechargeable battery cell group. Therefore, the voltage control circuit BT06 is the rechargeable battery. When the number of battery cells BT09 included in the discharge battery cell group is larger than the number of battery cells BT09 included in the rechargeable battery cell group, it is necessary to prevent an excessive charging voltage from being applied to the rechargeable battery cell group. Therefore, the voltage control circuit BT06 is the rechargeable battery. ​​The transformer circuit BT07 is configured to step down the discharge voltage (Vdis) within the range where the cell group can be charged. A transformer control signal S3 for controlling this is output.

[0440] Also, when the number of battery cells BT09 included in the discharge battery cell group is less than or equal to the number of battery cells BT09 included in the charge battery cell group, it is necessary to ensure the charging voltage required to charge the charge battery cell group. Therefore, the transformer control circuit BT06 outputs a transformer control signal S3 for controlling the transformer circuit BT07 to step up the discharge voltage (Vdis) within the range where an excessive charging voltage is not applied to the charge battery cell group. 07.

[0441] Note that the voltage value for the excessive charging voltage can be determined in consideration of the product specifications of the battery cell BT09 used in the battery unit BT08. Also, the voltage stepped up and down by the transformer circuit BT07 is applied to the terminal pair BT02 as the charging voltage (Vcha).

[0442] Here, an operation example of the transformer control circuit BT06 in the present embodiment will be described with reference to FIGS. 31(A) to (C). FIGS. 31(A) to (C) are conceptual diagrams for explaining an operation example of the transformer control circuit BT06 corresponding to the discharge battery cell group and the charge battery cell group described in FIGS. 28(A) to (C). Note that FIGS. 31(A) to (C) illustrate the battery control unit BT41. The battery control unit BT41 is composed of the terminal pair BT01, the terminal pair BT02, the switching control circuit BT03, the switching circuit BT04, the switching circuit BT05, the transformer control circuit BT06, and the transformer circuit BT07 as described above.

[0443] In the example shown in FIG. 31(A), as described in FIG. 28(A), three consecutive high voltages ​​​​​​​​​​​Cells a to c and one low-voltage cell d are connected in series. In this case, as shown in FIG. As explained above with reference to FIG. 1, the switching control circuit BT03 controls the high voltage cells a to c to a discharge voltage The low-voltage cell d is determined as the battery cell group, and the low-voltage cell d is determined as the charging battery cell group. The control circuit BT06 is based on the number of battery cells BT09 included in the discharge battery cell group. , the discharge voltage (Vdi s) to charging voltage (Vcha) is calculated.

[0444] The number of battery cells BT09 included in the discharge battery cell group is equal to the number of battery cells BT09 included in the charge battery cell group. When the number of the battery cells is larger than the number of the BT09, the discharge voltage is directly applied to the terminal pair BT02 without being transformed. When this voltage is applied, a current is applied to the battery cell BT09 in the charging battery cell group via the terminal pair BT02. There is a possibility that an excessive voltage is applied. Therefore, in the case shown in FIG. In this case, the charge voltage (Vcha) applied to the terminal pair BT02 must be lower than the discharge voltage. Furthermore, in order to charge the battery cell group, the charging voltage must be It must be greater than the total voltage of the battery cells BT09 included. Therefore, the transformer control circuit B T06 is the charging current based on the number of battery cells BT09 included in the discharge battery cell group. The conversion ratio N is set to be larger than the ratio of the number of battery cells BT09 included in the battery cell group.

[0445] The transformer control circuit BT06 determines the number of battery cells BT09 included in the discharge battery cell group as a standard. The conversion ratio N is set to 1 for the ratio of the number of battery cells BT09 included in the charging battery cell group when At this time, the charging voltage is preferably set to be about 10% higher than the voltage of the charging battery cell group. Although it also increases, in reality, the charging voltage becomes equal to the voltage of the rechargeable battery cell group. However, the transformer control circuit BT06 makes the voltage of the rechargeable battery cell group equal to the charging voltage according to the turns ratio N and causes a current to flow through the rechargeable battery cell group for charging. This current becomes the value set in the transformer control circuit BT06.

[0446] In the example shown in Fig. 31(A), since the number of battery cells BT09 included in the discharge battery cell group is 3 and the number of battery cells BT09 included in the rechargeable battery cell group is 1, the transformer control circuit BT06 calculates a value slightly larger than 1 / 3 as the turns ratio N. Then, the transformer control circuit BT06 steps down the discharge voltage according to the turns ratio N and outputs a transformer signal S3 that converts it to the charging voltage to the transformer circuit BT07. Then, the transformer circuit BT07 applies the stepped-up charging voltage according to the transformer signal S3 to the terminal pair BT02. And the charging voltage applied to the terminal pair BT02 charges the battery cell BT09 included in the rechargeable battery cell group.

[0447] Also, in the examples shown in Fig. 31(B) and Fig. 31(C), similar to Fig. 31(A), the turns ratio N is calculated. In the examples shown in Fig. 31(B) and Fig. 31(C), since the number of battery cells BT09 included in the discharge battery cell group is less than or equal to the number of battery cells BT09 included in the rechargeable battery cell group, the turns ratio N is 1 or more. Therefore, in this case, the transformer control circuit BT06 outputs a transformer signal S3 that steps up the discharge voltage and converts it to the charging voltage. The transformer circuit BT07 converts the discharge voltage applied to the terminal pair BT01

[0448] to the charging voltage based on the transformer signal S3. Then, the transformer circuit BT07 applies the converted charging voltage to the terminal pair BT0 ​Apply it to 2. Here, the transformer circuit BT07 electrically insulates between the terminal pair BT01 and the terminal pair BT02. As a result, the transformer circuit BT07 prevents a short circuit caused by the difference in the absolute voltage of the negative terminal of the battery cell BT09 located at the lowest current in the discharge battery cell group and the absolute voltage of the negative terminal of the battery cell BT09 located at the most downstream in the charge battery cell group. Further, as described above, the transformer circuit BT07 converts the discharge voltage, which is the total voltage of the discharge battery cell group, into a charge voltage based on the transformer signal S3.

[0449] Also, the transformer circuit BT07 can use, for example, an isolated DC (Direct Current)-DC converter or the like. In this case, the transformer control circuit BT06 outputs a signal for controlling the on / off ratio (duty ratio) of the isolated DC-DC converter as the transformer signal S3, thereby controlling the charge voltage converted by the transformer circuit BT07.

[0450] Note that the isolated DC-DC converter includes a flyback method, a forward method, an RCC ( Ringing Choke Converter) method, a push-pull method, a half-bridge ridge method, and a full-bridge method, etc. An appropriate method is selected according to the magnitude of the target output voltage.

[0451] The configuration of the transformer circuit BT07 using an isolated DC-DC converter is shown in FIG. 32. The isolated DC-DC converter BT51 has a switch section BT52 and a transformer section BT53. The switch section BT52 is a switch that switches the on / off of the operation of the isolated DC-DC converter. For example, it is a MOSFET (Metal-Oxide-Semiconduc ​​​​​​​​​​a field-effect transistor, a bipolar transistor, etc. It is realized by using, for example, a switch unit BT52, etc. The switch unit BT52 periodically switches between the on state and the off state of the isolated DC-DC converter BT51 based on a voltage conversion signal S3 output from the voltage control circuit BT06 and used to control the on / off ratio. Note that the switch unit BT52 can have various configurations depending on the type of isolated DC-DC converter used. It is realized by using, for example, a switch unit BT52, etc. The switch unit BT52 periodically switches between the on state and the off state of the isolated DC-DC converter BT51 based on a voltage conversion signal S3 output from the voltage control circuit BT06 and used to control the on / off ratio. Note that the switch unit BT52 can have various configurations depending on the type of isolated DC-DC converter used. It is realized by using, for example, a switch unit BT52, etc. The switch unit BT52 periodically switches between the on state and the off state of the isolated DC-DC converter BT51 based on a voltage conversion signal S3 output from the voltage control circuit BT06 and used to control the on / off ratio. Note that the switch unit BT52 can have various configurations depending on the type of isolated DC-DC converter used. It is realized by using, for example, a switch unit BT52, etc. The switch unit BT52 periodically switches between the on state and the off state of the isolated DC-DC converter BT51 based on a voltage conversion signal S3 output from the voltage control circuit BT06 and used to control the on / off ratio. Note that the switch unit BT52 can have various configurations depending on the type of isolated DC-DC converter used. The transformer unit BT53 converts the discharge voltage applied from the terminal pair BT01 into a charging voltage. Specifically, the transformer unit BT53 operates in conjunction with the on / off state of the switch unit BT52 and converts the discharge voltage into a charging voltage according to its on / off ratio. This charging voltage increases as the time in the on state becomes longer during the switching period of the switch unit BT52. On the other hand, the charging voltage decreases as the time in the on state becomes shorter during the switching period of the switch unit BT52. When using an isolated DC-DC converter, the terminal pair BT01 and the terminal pair BT02 can be insulated from each other inside the transformer unit BT53. The transformer unit BT53 converts the discharge voltage applied from the terminal pair BT01 into a charging voltage. Specifically, the transformer unit BT53 operates in conjunction with the on / off state of the switch unit BT52 and converts the discharge voltage into a charging voltage according to its on / off ratio. This charging voltage increases as the time in the on state becomes longer during the switching period of the switch unit BT52. On the other hand, the charging voltage decreases as the time in the on state becomes shorter during the switching period of the switch unit BT52. When using an isolated DC-DC converter, the terminal pair BT01 and the terminal pair BT02 can be insulated from each other inside the transformer unit BT53. The transformer unit BT53 converts the discharge voltage applied from the terminal pair BT01 into a charging voltage. Specifically, the transformer unit BT53 operates in conjunction with the on / off state of the switch unit BT52 and converts the discharge voltage into a charging voltage according to its on / off ratio. This charging voltage increases as the time in the on state becomes longer during the switching period of the switch unit BT52. On the other hand, the charging voltage decreases as the time in the on state becomes shorter during the switching period of the switch unit BT52. When using an isolated DC-DC converter, the terminal pair BT01 and the terminal pair BT02 can be insulated from each other inside the transformer unit BT53. The transformer unit BT53 converts the discharge voltage applied from the terminal pair BT01 into a charging voltage. Specifically, the transformer unit BT53 operates in conjunction with the on / off state of the switch unit BT52 and converts the discharge voltage into a charging voltage according to its on / off ratio. This charging voltage increases as the time in the on state becomes longer during the switching period of the switch unit BT52. On the other hand, the charging voltage decreases as the time in the on state becomes shorter during the switching period of the switch unit BT52. When using an isolated DC-DC converter, the terminal pair BT01 and the terminal pair BT02 can be insulated from each other inside the transformer unit BT53. The transformer unit BT53 converts the discharge voltage applied from the terminal pair BT01 into a charging voltage. Specifically, the transformer unit BT53 operates in conjunction with the on / off state of the switch unit BT52 and converts the discharge voltage into a charging voltage according to its on / off ratio. This charging voltage increases as the time in the on state becomes longer during the switching period of the switch unit BT52. On the other hand, the charging voltage decreases as the time in the on state becomes shorter during the switching period of the switch unit BT52. When using an isolated DC-DC converter, the terminal pair BT01 and the terminal pair BT02 can be insulated from each other inside the transformer unit BT53. When using an isolated DC-DC converter, the terminal pair BT01 and the terminal pair BT02 can be insulated from each other inside the transformer unit BT53. When using an isolated DC-DC converter, the terminal pair BT01 and the terminal pair BT02 can be insulated from each other inside the transformer unit BT53.

[0452] The processing flow of the power storage device BT00 in this embodiment will be described with reference to FIG. 33. FIG. 33 is a flowchart showing the processing flow of the power storage device BT00. The processing flow of the power storage device BT00 in this embodiment will be described with reference to FIG. 33. FIG. 33 is a flowchart showing the processing flow of the power storage device BT00.

[0453] First, the power storage device BT00 acquires the voltages measured for each of the plurality of battery cells BT09 (step S1001). Then, the power storage device BT00 determines whether or not the start condition for the operation of equalizing the voltages of the plurality of battery cells BT09 is satisfied (step S1002). This start condition is, for example, that the difference between the maximum value and the minimum value of the voltages measured for each of the plurality of battery cells BT09 is within a certain range. First, the power storage device BT00 acquires the voltages measured for each of the plurality of battery cells BT09 (step S1001). Then, the power storage device BT00 determines whether or not the start condition for the operation of equalizing the voltages of the plurality of battery cells BT09 is satisfied (step S1002). This start condition is, for example, that the difference between the maximum value and the minimum value of the voltages measured for each of the plurality of battery cells BT09 is within a certain range. First, the power storage device BT00 acquires the voltages measured for each of the plurality of battery cells BT09 (step S1001). Then, the power storage device BT00 determines whether or not the start condition for the operation of equalizing the voltages of the plurality of battery cells BT09 is satisfied (step S1002). This start condition is, for example, that the difference between the maximum value and the minimum value of the voltages measured for each of the plurality of battery cells BT09 is within a certain range. First, the power storage device BT00 acquires the voltages measured for each of the plurality of battery cells BT09 (step S1001). Then, the power storage device BT00 determines whether or not the start condition for the operation of equalizing the voltages of the plurality of battery cells BT09 is satisfied (step S1002). This start condition is, for example, that the difference between the maximum value and the minimum value of the voltages measured for each of the plurality of battery cells BT09 is within a certain range. It can be set to whether it is equal to or greater than a certain threshold value. If this start condition is not satisfied (step S1002: NO), since the voltages of the respective battery cells BT09 are balanced, the power storage device BT00 does not execute the subsequent processing. On the other hand, if the start condition is satisfied (step S1002: YES), the power storage device BT00 executes processing to equalize the voltages of the respective battery cells BT09. In this processing, the power storage device BT00 determines whether each battery cell BT09 is a high-voltage cell or a low-voltage cell based on the measured voltage for each cell (step S1003 ). Then, the power storage device BT00 determines a discharge battery cell group and a charge battery cell group based on the determination result (step S1004). Further, the power storage device BT00 generates a control signal S1 for setting the determined discharge battery cell group as the connection destination of the terminal pair BT01, and a control signal S2 for setting the determined charge battery cell group as the connection destination of the terminal pair BT02 (step S100 5). The power storage device BT00 outputs the generated control signal S1 and control signal S2 to the switching circuit BT04 and the switching circuit BT05, respectively. Then, the switching circuit BT04 connects the terminal pair BT01 and the discharge battery cell group, and the switching circuit BT05 connects the terminal pair BT02 and the charge battery cell group (step S1006). Also, the power storage device BT00 generates a transformer signal S3 based on the number of battery cells BT09 included in the discharge battery cell group and the number of battery cells BT09 included in the charge battery cell group (step S1 007). Then, the power storage device BT00 converts the discharge voltage applied to the terminal pair BT01 into a charge voltage based on the transformer signal S3 and applies it to the terminal pair BT02 (step S1008 ). Thereby, the charge of the discharge battery cell group is moved to the charge battery cell group. )

[0454] Also, in the flowchart of FIG. 33, although a plurality of steps are described in order, the execution order of each step is not limited to the described order. That is, the execution order of each step is not limited to the order of the description.

[0455] As described above, according to the present embodiment, when moving charge from the discharge battery cell group to the charge battery cell group, it is not necessary to have a configuration such as a capacitor method that temporarily stores the charge from the discharge battery cell group and then discharges it to the charge battery cell group. Thereby, the charge transfer efficiency per unit time can be improved. Further, by the switching circuit BT04 and the switching circuit BT05, among the discharge battery cell group and the charge battery cell group, the battery cells connected to the transformer circuit can be individually switched. That is, the battery cells connected to the transformer circuit among the discharge battery cell group and the charge battery cell group can be individually switched.

[0456] Furthermore, by the transformer circuit BT07, based on the number of battery cells BT09 included in the discharge battery cell group and the number of battery cells BT09 included in the charge battery cell group, the discharge voltage applied to the terminal pair BT01 is converted into a charge voltage and applied to the terminal pair BT02. Thereby, regardless of how the battery cells BT09 on the discharge side and the charge side are selected, charge transfer can be realized without problems. That is, regardless of how the battery cells BT09 on the discharge side and the charge side are selected, charge transfer can be realized without problems. That is, charge transfer can be achieved without any problems regardless of how the battery cells BT09 on the discharge side and the charge side are selected.

[0457] Furthermore, by using OS transistors for the transistor BT10 and the transistor BT13, the amount of charge leaking from the battery cell BT09 that does not belong to the charge battery cell group and the discharge battery cell group can be reduced. Thereby, a decrease in the capacity of the battery cell BT09 that does not contribute to charging and discharging can be suppressed. Also, the OS transistor has less variation in characteristics with respect to heat compared to the Si transistor. Thereby, when the temperature of the battery cell BT09 rises, Normal operations such as switching between the conducting state and the non-conducting state according to the control signals S1 and S2 ca...

Claims

1. The present invention relates to an active material having a lithium manganese composite oxide, a conductive additive, a first reduced graphene oxide, a second reduced graphene oxide, and a binder, the active material particles have a cleavage surface; the first reduced graphene oxide is in contact with a first region of the active material particle; the second reduced graphene oxide has a second region covering the cleavage plane; The first reduced graphene oxide has a region in contact with the second reduced graphene oxide.

2. A first step of preparing an electrode mixture paste by kneading a lithium manganese composite oxide coated with reduced graphene oxide, a conductive assistant, graphene oxide, a binder, and a solvent, In the first step, the content of the conductive assistant is 1 wt % or more and 5 wt % or less with respect to the total amount of the lithium manganese composite oxide, In the first step, a weight of the graphene oxide is 0.2 wt % or more and 16 wt % or less with respect to a total weight of the electrode mixture paste; a second step of applying the electrode mixture paste to a current collector after the first step and drying the electrode mixture paste with hot air at a temperature of 50° C. or higher and 180° C. or lower to form an active material layer; a third step of immersing the active material layer in alcohol for 30 minutes to 1 hour after the second step; a fourth step of performing a heat treatment at a temperature of 50° C. or more and 300° C. or less for 1 hour or more and 48 hours or less after the third step, thereby producing an electrode.

3. In claim 2, The method for producing an electrode, wherein the alcohol is selected from the group consisting of methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, isobutyl alcohol, and tert-butyl alcohol.

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