Positive electrode active material for lithium ion secondary battery and lithium ion secondary battery

Abstract

To increase the capacity per weight of a power storage device, increase the capacity per weight of an electrode, increase the capacity per weight of a particle with a positive electrode active material, achieve high energy density by increasing the amount of lithium ions per weight of a particle with a positive electrode active material, and stably perform a battery reaction at a higher potential in a positive electrode.SOLUTION: A particle includes a first region, a second region in contact with at least a part of a surface of the region and existing outside the first region, and a third region in contact with at least a part of a surface of the region and existing outside the second region. The first and second regions contain Li and O. At least one of the first and second regions contains Mn. At least one of the first and second regions contains an element expressed by M. The first region includes a first crystal with a layered rock salt structure. The second region includes a second crystal with a layered rock salt structure. The direction of the first crystal and the direction of the second crystal are different.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an article, a method, or a manufacturing method. Alternatively, the present invention relates to a process, a machine , a manufacture, or a composition of matter. In particular , one aspect of the present invention relates to a semiconductor device, a display device, a light-emitting device, an imaging device, 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 a power storage device structure and a manufacturing method thereof. In particular, it relates to a positive electrode active material of a lithium ion secondary battery .

Background Art

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

[0003] The basic configuration of a secondary 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 secondary battery, a material capable of occluding and releasing lithium is used as the active material of the positive electrode and the negative electrode.

[0004]

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

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] One aspect of the present invention aims to increase the capacity per unit volume and / or per unit weight of an energy storage device. Another aspect of the present invention aims to increase the capacity per unit volume and / or per unit weight of an electrode.

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

[0008] Alternatively, one aspect of the present invention aims to stably perform a battery reaction at a higher potential in a positive electrode having a positive electrode active material.

[0009] Alternatively, one aspect of the present invention is an energy storage device with suppressed capacity degradation during charge and discharge cycles. One of the problems is to provide it. Or, one aspect of the present invention is a positive electrode that can be manufactured at low cost One of the problems is to provide an active material.

[0010] In addition, as a positive electrode active material of a lithium-ion secondary battery, it is desired that the ionic conductivity and electric conductivity are high 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.

[0011] Or, one aspect of the present invention is to provide a method for manufacturing an electrode of an electric storage device as one of the problems Or, 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 of one.

[0012] Or, one aspect of the present invention is to provide a novel substance as one of the problems. Or, the present invention is to provide a novel positive electrode active material as one of the problems. Or, one aspect of the present invention is to provide novel particles having a positive electrode active material as one of the problems. Or, the present invention is to provide a novel electric storage device as one of the problems. Or, one aspect of the present invention is to provide a novel battery as one of the problems. Or, one aspect of the present invention is to provide a novel lithium-ion secondary battery as one of the problems.

[0013] 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 other problems will be obvious from the description in the specification, drawings, claims, etc., and it is possible to extract these other problems from the description in the specification, drawings, claims, etc.

Means for Solving the Problems

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

[0015] The particles having a lithium manganese composite oxide, which are one aspect of the present invention, have a first region and a second region. Further, the particles having a lithium manganese composite oxide, which are one aspect of the present invention, preferably have a third region. and 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, the outside indicates being closer to the surface of the particle. The third region is preferably in contact with at least a part of the surface of the second region and is located outside the second region.

[0016] When the particles of one aspect of the present invention have a second region, the discharge capacity may be improved when the particles of one aspect of the present invention are used as a positive electrode active material of a storage battery. Also, the discharge voltage may be increased. and When the particles of one aspect of the present invention have a third region, the discharge capacity may be improved when the particles of one aspect of the present invention are used as a positive electrode active material of a storage battery. Also, the discharge voltage may be increased.

[0017] When the particles of one aspect of the present invention have a second region, the discharge capacity may be improved when the particles of one aspect of the present invention are used as a positive electrode active material of a storage battery. Also, the discharge voltage may be increased. and When the particles of one aspect of the present invention have a third region, the discharge capacity may be improved when the particles of one aspect of the present invention are used as a positive electrode active material of a storage battery. Also, the discharge voltage may be increased.

[0018] When the particles of one aspect of the present invention have a third region, the discharge capacity may be improved when the particles of one aspect of the present invention are used as a positive electrode active material of a storage battery. Also, the discharge voltage may be increased. and When the particles of one aspect of the present invention have a third region, the discharge capacity may be improved when the particles of one aspect of the present invention are used as a positive electrode active material of a storage battery. Also, the discharge voltage may be increased.

[0019] The first region and the second region have lithium and oxygen. Further, at least one of the first region and the second region has manganese. Also, at least one of the first region and the second region has element M. Here, element M is preferably a metal element other than lithium and manganese, or silicon or phosphorus, and is preferably Ni, Ga, Fe, Mo and The first region and the second region have lithium and oxygen. Further, at least one of the first region and the second region has manganese. Also, at least one of the first region and the second region has element M. Here, element M is preferably a metal element other than lithium and manganese, or silicon or phosphorus, and is preferably Ni, Ga, Fe, Mo ​ An element selected from In, Nb, Nd, Co, Sm, Mg, Al, Ti, Cu, or Zn, Si, or P is more preferable, and nickel is even more preferable. Further, it is more preferable that both the first region and the second region have both manganese and element M.

[0020]

[0021] Further, the third region preferably includes the surface of particles having a lithium manganese composite oxide which is one aspect of the present invention.

[0022] When a power storage device is manufactured using particles having a lithium manganese composite oxide which is one aspect of the present invention, the third region is preferably more stable than the first region and the second region with respect to battery reactions such as charging and discharging.

[0023] Here, the second region may have a crystal structure different from that of the first region. Or, the second region may have crystals with different orientations from those of the first region. Here, different orientations mean that the orientations of the respective crystals are different by an angle greater than, for example, 10°.

[0024] 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. When the second region has a spinel-type structure, when particles of one aspect of the present invention are used as a positive electrode active material of a storage battery, the discharge capacity may be improved. Also, the discharge voltage may be increased.

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

[0026] 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. It may have.

[0027] Also, a transition layer may be provided between the second region and the first region. Alternatively, a mixed layer may be provided between the second region and the first region. It may have.

[0028] One aspect of the present invention is particles having a lithium manganese composite oxide, having a first region and a second region, the second region being in contact with at least a part of the first region, the first region and the second region having lithium and oxygen, at least one of the first region or the second region having manganese, at least one of the first region or the second region having an element represented by M, the first region having a first crystal with a layered rock salt structure, the second region having a second crystal with a layered rock salt structure, and the {0 0 1} plane of the first crystal being parallel to at least one of the {1 0 0} plane, {1 3 -1} plane, or {-1 3 1} plane of the second crystal. Here, two planes being parallel means, for example, that the angle between the normal vectors of the two planes is 10° or less, more preferably 5° or less, and even more preferably 3° or less. Also, two lines being parallel means, for example, that the angle between the two lines is 10° or less, more preferably 5° or less, and even more preferably 3° or less. and the second region having a second crystal with a layered rock salt structure, the {0 0 1} plane of the first crystal being parallel to at least one of the {1 0 0} plane, {1 3 -1} plane, or {-1 3 1} plane of the second crystal. Here, two planes being parallel means, for example, that the angle between the normal vectors of the two planes is 10° or less, more preferably 5° or less, and even more preferably 3° or less. Also, two lines being parallel means, for example, that the angle between the two lines is 10° or less, more preferably 5° or less, and even more preferably 3° or less. and the second region having lithium and oxygen, at least one of the first region or the second region having manganese, at least one of the first region or the second region having an element represented by M, the first region having a first crystal with a layered rock salt structure, the second region having a second crystal with a layered rock salt structure, and the {0 0 1} plane of the first crystal being parallel to at least one of the {1 0 0} plane, {1 3 -1} plane, or {-1 3 1} plane of the second crystal. Here, two planes being parallel means, for example, that the angle between the normal vectors of the two planes is 10° or less, more preferably 5° or less, and even more preferably 3° or less. Also, two lines being parallel means, for example, that the angle between the two lines is 10° or less, more preferably 5° or less, and even more preferably 3° or less. At least one of the first region or the second region has manganese, at least one of the first region or the second region has an element represented by M, the first region has a first crystal with a layered rock salt structure, the second region has a second crystal with a layered rock salt structure, and the {0 0 1} plane of the first crystal is parallel to at least one of the {1 0 0} plane, {1 3 -1} plane, or {-1 3 1} plane of the second crystal. Here, two planes being parallel means, for example, that the angle between the normal vectors of the two planes is 10° or less, more preferably 5° or less, and even more preferably 3° or less. Also, two lines being parallel means, for example, that the angle between the two lines is 10° or less, more preferably 5° or less, and even more preferably 3° or less. The first region has a first crystal with a layered rock salt structure, the second region has a second crystal with a layered rock salt structure, and the {0 0 1} plane of the first crystal is parallel to at least one of the {1 0 0} plane, {1 3 -1} plane, or {-1 3 1} plane of the second crystal. Here, two planes being parallel means, for example, that the angle between the normal vectors of the two planes is 10° or less, more preferably 5° or less, and even more preferably 3° or less. Also, two lines being parallel means, for example, that the angle between the two lines is 10° or less, more preferably 5° or less, and even more preferably 3° or less. The {0 0 1} plane of the first crystal is parallel to at least one of the {1 0 0} plane, {1 3 -1} plane, or {-1 3 1} plane of the second crystal. Here, two planes being parallel means, for example, that the angle between the normal vectors of the two planes is 10° or less, more preferably 5° or less, and even more preferably 3° or less. Also, two lines being parallel means, for example, that the angle between the two lines is 10° or less, more preferably 5° or less, and even more preferably 3° or less. At least one of the {1 0 0} plane, {1 3 -1} plane, or {-1 3 1} plane of the second crystal. Here, two planes being parallel means, for example, that the angle between the normal vectors of the two planes is 10° or less, more preferably 5° or less, and even more preferably 3° or less. Also, two lines being parallel means, for example, that the angle between the two lines is 10° or less, more preferably 5° or less, and even more preferably 3° or less. Here, two planes being parallel means, for example, that the angle between the normal vectors of the two planes is 10° or less, more preferably 5° or less, and even more preferably 3° or less. Also, two lines being parallel means, for example, that the angle between the two lines is 10° or less, more preferably 5° or less, and even more preferably 3° or less. Here, two planes being parallel means, for example, that the angle between the normal vectors of the two planes is 10° or less, more preferably 5° or less, and even more preferably 3° or less. Also, two lines being parallel means, for example, that the angle between the two lines is 10° or less, more preferably 5° or less, and even more preferably 3° or less. Here, two planes being parallel means, for example, that the angle between the normal vectors of the two planes is 10° or less, more preferably 5° or less, and even more preferably 3° or less. Also, two lines being parallel means, for example, that the angle between the two lines is 10° or less, more preferably 5° or less, and even more preferably 3° or less.

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

[0030] Also, in the above configuration, the {0 0 1} plane of the first crystal is at least one of the {1 0 0} plane, {1 3 -1} plane, or {-1 3 1} plane of the second crystal It is preferably parallel to any one of them.

[0031] Or, one aspect of the present invention is particles having a lithium manganese composite oxide, having a first region and a second region, the second region being in contact with at least a part of the first region, and the first region and the second region having lithium and oxygen, and at least one of the first region or the second region has manganese, and at least one of the first region or the second region has an element represented by M, the first region having a first crystal with a layered rock salt structure, and the second region is a particle having a second crystal with a spinel structure.

[0032] Or, one aspect of the present invention is particles having a lithium manganese composite oxide, having a first region and a second region, the second region being in contact with at least a part of the first region, and the first region and the second region having lithium and oxygen, and at least one of the first region or the second region ​​At least one of them contains manganese, and at least one of the first region or the second region contains an element represented by M, and the atomic number ratio of lithium, manganese, element M, and oxygen in the first region is represented as a1:b1:c1:d1, and the atomic number ratio of lithium, manganese, element M, and oxygen in the second region is represented as a2:b2:c2:d2, and d1÷(b1 + c1) (=A 1) is 2.2 or more, and d2÷(b2 + c2) (=A2) is less than 2.2 is a certain particle. Thus, when A2 is smaller than A1, in one aspect of the present invention when the particle is used as a positive electrode active material of a storage battery, the stability of the second region against charge and discharge can be enhanced compared to the first region in some cases. Also, when the particle of one aspect of the present invention is used as a positive electrode active material of a storage battery, the discharge capacity can be improved in some cases. Also the discharge voltage can be increased in some cases.

[0033] In addition, in the above configuration, it preferably has a third region in contact with at least a part of the second region and the third region preferably contains carbon.

[0034] In addition, in the above configuration, it is preferable that the thickness of the third region is 0.1 nm or more and 30 nm or less.

[0035] Or, one aspect of the present invention is a particle having a lithium manganese composite oxide, having a first region and a second region, the second region being in contact with at least a part of the first region, and the first region and the second region containing lithium, manganese, an element represented by M, and oxygen, and the atomic number ratio of lithium, manganese, element M, and oxygen in the first region is a1:b1: ​The atomic number ratio of lithium, manganese, element M, and oxygen in the second region, represented by c1:d1 is represented by a2:b2:c2:d2, d1÷(b1 + c1) is 2.2 or more, and d2÷ (b2 + c2) is less than 2.2. The first region has a first crystal with a layered rock salt structure and the second region has a second crystal with a layered rock salt structure. The {0 0 1} plane of the first crystal is a particle parallel to at least one of the {1 0 0} plane, {1 3 -1} plane, or {-1 3 1} plane of the second crystal.

[0036] Also, in the above configuration, the second region has a layered region, and the thickness of the layered region is preferably 0.1 nm or more and 30 nm or less.

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

[0038] Here, when a power storage device is manufactured using particles having a lithium manganese composite oxide, which is one aspect of the present invention, the amount of lithium in the particles changes due to a battery reaction, for example, charging or discharging. For example, when charging, lithium desorbs as lithium ions, the amount of lithium in the particles decreases, and the decrease amount also changes depending on the depth of charging.

[0039] One aspect of the present invention is to mix particles, a binder, and a solvent to prepare a mixture. The particles contain lithium, manganese, element M, and oxygen. Element M is one or more elements selected from chromium, cobalt, al uminum, nickel, iron, magnesium, molybdenum, zinc, indium, gallium, copper, titanium, niobium, silicon, and phosphorus. The mixture A mixture layer is formed on a current collector, and the mixture layer is subjected to a heat treatment to form an electrode layer. The electrode layer is made of at least one of lithium, manganese, element M, and oxygen, and a valence layer. Method for preparing an electrode layer having a compound having a bond with at least one element contained in an inhibitor In the above-mentioned structure, the compound is a compound containing lithium, manganese, or a small amount of the element M. Preferably, the particles contain at least one of lithium, fluorine, and It is preferred to have an oxide having manganese, the element M, and oxygen.

[0040] Another embodiment of the present invention is an electrode layer provided over a current collector. The electrode layer includes particles and The binder and the solvent are included, and the particles include lithium, manganese, an element M, and oxygen. The element M is chromium, cobalt, aluminum, nickel, iron, magnesium, molybdenum, etc. Choose from: tin, zinc, indium, gallium, copper, titanium, niobium, silicon, and phosphorus. The electrode layer is composed of lithium, manganese, element M, and a small amount of oxygen. A compound having a bond between at least one of the above and at least one element contained in the binder. In the above structure, the compound is an electrode layer having lithium, manganese, or It is preferable that the particles contain at least one of the elements M and fluorine. It is preferred to have an oxide having lithium, manganese, the element M, and oxygen.

[0041] Here, the present invention relates to a storage battery using particles having a lithium manganese composite oxide. When an electric device is produced, the amount of lithium contained in the particles is reduced by a battery reaction, for example, by charging or discharging. For example, when charging, lithium is released as lithium ions, and the particles The amount of lithium in the child decreases, and the amount of decrease also changes depending on the depth of charge.

Advantages of the Invention

[0042] According to one aspect of the present invention, the capacity per unit volume and / or per unit weight of the power storage device can be increased. Also, according to one aspect of the present invention, the capacity per unit volume and / or per unit weight of the electrode can be increased.

[0043] In addition, according to one aspect of the present invention, the capacity per unit volume and / or per unit weight of the particles having the positive electrode active material can be increased. Also, according to one aspect of the present invention, the amount of lithium ions per unit volume and / or per unit weight of the particles having the positive electrode active material is increased, and a high energy density can be realized.

[0044] In addition, according to one aspect of the present invention, in the positive electrode having the positive electrode active material, the battery reaction can be stably performed at a higher potential.

[0045] In addition, according to one aspect of the present invention, a power storage device with suppressed capacity degradation during charge and discharge cycles can be provided. Also, according to one aspect of the present invention, a positive electrode active material that can be manufactured at low cost can be provided.

[0046] In addition, as characteristics required for the positive electrode active material of a lithium ion secondary battery, it is desirable that the ionic conductivity and electric conductivity are high. According to one aspect of the present invention, a positive electrode active material having high ionic conductivity and / or electric conductivity can be provided.

[0047] In addition, according to one aspect of the present invention, a method for manufacturing the electrode of the power storage device can be provided. Also, According to one aspect of the present invention, a method for producing a positive electrode active material of a secondary battery can be provided.

[0048] Also, according to one aspect of the present invention, a novel substance can be provided. Also, according to one aspect of the present invention, a novel positive electrode active material can be provided. Also, according to one aspect of the present invention, novel particles having a positive electrode active material can be provided. Also, according to one aspect of the present invention, a novel power storage device can be provided. Also, according to one aspect of the present invention, a novel battery can be provided. Also, according to one aspect of the present invention, a novel lithium-ion secondary battery can be provided.

[0049] Note that the description of these effects does not prevent the existence of other effects. Note that one aspect of the present invention does not necessarily have to have all of these effects. Note that other effects will become apparent from the description in the specification, drawings, claims, etc., and it is possible to extract these other effects from the description in the specification, drawings, claims, etc.

Brief Description of the Drawings

[0050]

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MODE FOR CARRYING OUT THE INVENTION

[0051] 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. When explaining the configuration of the invention using drawings, the same reference numerals are commonly used even between different drawings. When referring to similar ones, the hatch patterns are the same, and there may be cases where they are not particularly labeled. Those skilled in the art will easily understand this. Also, the present invention is not to be construed as being limited to the description of the embodiments shown below. When explaining the configuration of the invention using drawings, the same reference numerals are commonly used even between different drawings. When referring to similar ones, the hatch patterns are the same, and there may be cases where they are not particularly labeled.

[0052] In the drawings, the size, thickness of the film (layer), or region may be exaggerated for clarity.

[0053] The ordinal numbers attached as the first, second, etc. are used for convenience and do not indicate the process order or the lamination order. Therefore, for example, "the first" can be appropriately replaced with "the second" or "the third" and explained. Also, the ordinal numbers described in this specification, etc., and the ordinal numbers used to specify an aspect of the present invention may not match. The active material refers only to the material related to the insertion and extraction of ions that are carriers, but in this specification, etc., it may include a layer covering the 'active material'.

[0054]

[0055] (Embodiment 1) In this embodiment, "particles having a lithium manganese composite oxide", which is an aspect of the present invention, will be described. Also, an electrode having such particles will be described.

[0056] A lithium manganese composite oxide according to an aspect of the present invention has a composition formula Li a Mn b M c O d represented by It is possible. Here, the element M is a metal element selected from elements other than lithium and manganese, or it is preferable to use silicon or phosphorus. Also, 0 ≦ a / (b + c) < 2, and c > 0 , and it is preferable to satisfy 0.26 ≦ (b + c) / d < 0.5. Note that the lithium man gan composite oxide refers to an oxide containing at least lithium and manganese, and chromium, co balt, aluminum, nickel, iron, magnesium, molybdenum, zinc, indium, gallium, copper, titanium, niobium, silicon, and phosphorus, etc., and may contain at least one element selected from the group consisting of. Also, the lithium manganese composite oxide preferably has a layered rock salt type crystal structure. Also, 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, for example, preferably has an average primary particle diameter of 5 nm or more and 50 μm or less .

[0057] <Synthesis> Next, a method for producing "particles having a lithium manganese composite oxide", which is one aspect of the present invention, will be described. In this embodiment, first, a lithium manganese composite oxide is synthesized. Thereafter, 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.

[0058] As raw materials for the lithium manganese composite oxide, manganese compounds and lithium compounds can be used. Also, together with the raw materials of the manganese compound and the lithium compound, chromium , cobalt, aluminum, nickel, iron, magnesium, molybdenum, zinc, indium Selected from the group consisting of mu, gallium, copper, titanium, niobium, silicon, phosphorus, etc. Raw materials of compounds containing at least one element can be used. As manganese compounds For example, manganese dioxide, trimanganese dioxide, manganese sesquioxide, hydrated manganese oxide Carbonate, manganese nitrate, etc. can be used. Also, as lithium compounds For example, lithium hydroxide, lithium carbonate, lithium nitrate, etc. can be used .

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

[0060] First, as shown in step S11 of FIG. 1, Li2CO3 and Mn CO3 and NiO are used as starting materials and weighed respectively.

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

[0062] 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.

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

[0064] Next, as shown in step S12 of FIG. 1, mix Li2CO3, MnCO3, and NiO. There is no particular limitation on the method of mixing the starting materials, and known crushers and grinders can be used. For example, a ball mill, a bead mill, a jet mill, a roller mill, etc. can be mentioned. Also, the crushing and grinding method may be dry or wet. When using a wet method, There is no particular limitation on the solvent that can be used, and for example, water, alcohol, acetone, etc. can be used.

[0065] When mixing the starting materials, if it is carried out wet, as shown in step S13 of FIG. 1, perform a heat treatment to evaporate the solvent contained in the mixed starting materials. The heat treatment performed here may be carried out at 50°C or higher and 150°C or lower. By performing the heat treatment, the solvent contained in the mixed starting materials is evaporated to obtain a mixed raw material.

[0066] Next, as shown in step S14 of FIG. 1, put the mixed raw material into a crucible and perform firing at 800°C or higher and 10 00°C or lower. The firing time is, for example, 5 hours or more and 20 hours or less, and dry air is used as the firing gas with a flow rate of 10 L / min. The firing atmosphere may be an air atmosphere or an atmosphere using oxygen gas. By firing the mixed raw material, a fired product (lithium manganese composite oxide) is formed.

[0067] As shown in FIG. 2(A), the lithium manganese composite oxide in which a plurality of primary particles synthesized by firing are sintered is in a state where a plurality of primary particles are sintered to form large secondary particles. That is. Therefore, as shown in step S15 of FIG. 1, a plurality of primary particles are sintered lithium The manganese composite oxide is subjected to a crushing treatment. By performing a crushing treatment on the fired product , the fired product is crushed into primary particles or into a powder close to the primary particles. In this specification and the like , the crushing treatment includes an operation in which the sintered product is crushed. Note that crushing means further crushing the primary particles The crushing treatment can be carried out using a known crusher or grinder, similar to the method of mixing the starting materials . For example, a ball mill, a bead mill, or the like can be used. Also, The crushing and grinding method may be dry or wet. There is no particular limitation on the solvent that can be used in the wet case, and for example, water, alcohol, acetone, etc. can be used .

[0068] Here, regarding the size of the particles after crushing and grinding, for example, it can be evaluated by measuring the specific surface area of the particles . 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 electrolyte can be increased. By increasing the contact area with the electrolyte , the reaction rate of the storage battery can be increased, and for example, the output characteristics can be improved .

[0069] It is preferable that the specific surface area of the particles may increase by performing a crushing treatment. The specific surface area of the particles having the lithium manganese composite oxide is preferably 0.1 m 2 / g or more. Also, if the specific surface area of the particles becomes too large, in the electrode manufactured using the particles, there may be a case where the amount of the binder is insufficient with respect to the surface area , and the strength may decrease. Here, the binder​​ Increasing the binder amount may decrease the capacity of the electrode per unit weight and unit volume. Therefore, the specific surface area of the particles having the lithium manganese composite oxide is, for example, 1 m 2 / g More than 50m 2 / g or less is preferable, and 5m 2 / g or more 30m 2 / g or less is more preferable.

[0070] In this embodiment, the lithium manganese composite oxide in which the primary particles are sintered is crushed by a crushing process using a bimetallic compound. This is done using a wet method with acetone in a rice mill.

[0071] When performing the crushing process in a wet manner, heating is required to evaporate the solvent after the crushing process. The heat treatment may be performed in the same manner as in step S13. Drying is carried out to obtain a powdered lithium manganese composite oxide.

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

[0073] Through the above process, the composition formula Li a Mn b M c O d Lithium manganese oxide composite represented by In this embodiment, the weight ratio (molar ratio) of the raw materials is expressed as L By setting the ratio of i2CO3:MnCO3:NiO=0.84:0.8062:0.318 The formula is Li 1.68 Mn 0.8062 M 0.318 Lithium manganese represented by O3 A complex oxide can be formed.

[0074] In addition, the lithium manganese composite oxide after the crushing treatment shown in step S15 is crushed. The impact of the crushing process may cause crystallinity to become disordered. Therefore, the powdered lithium manganese oxide after vacuum drying may have oxygen deficiencies. It is preferable to subject the calcium carbonate composite oxide to a heat treatment again.

[0075] By performing heat treatment on the lithium manganese composite oxide after crushing, oxygen deficiencies are repaired. In addition, the crystallinity disturbance caused by the crushing process can be restored. The powdered lithium manganese composite oxide after the crushing process may be crushed again. In this case, the crushing process can be performed using a method similar to that of step S15 in FIG. .

[0076] Here, the ratio of Li2CO3:MnCO3:NiO=0.84:0.8062:0.318 The raw material is used to produce a lithium manganese composite oxide in accordance with steps S11 to S16 shown in FIG. The temperature stability of the prepared sintered body was evaluated by differential scanning calorimetry. Figure 46 shows the differential scanning calorimetry (DSC) curve. The vertical axis shows heat flow and the horizontal axis shows temperature. As shown in Fig. 6, a peak indicating exothermic reaction was observed at 262.2°C. In this case, the lithium manganese compound according to one embodiment of the present invention was stable in the DSC evaluation. It can be seen that the composite oxide is stable even at a high temperature of 260 °C or lower.

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

[0078] Through the above steps, 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" means closer to the surface of the particle.

[0079] 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. Here, element M is preferably a metal element other than lithium and manganese, or silicon or phosphorus, and is more preferably selected from Ni, Ga, Fe, Mo , In, Nb, Nd, Co, Sm, Mg, Al, Ti, Cu, or Zn metal element, Si, or P, and even more preferably nickel.

[0080] <Coating layer> Next, a coating layer is provided on the obtained lithium manganese composite oxide. The coating layer preferably contains carbon. Since carbon has high conductivity, particles coated with carbon are used for the electrode of the storage battery. By doing so, for example, the resistance of the electrode can be lowered. Further, the coating layer may contain graphene oxide, or may contain reduced graphene oxide.

[0081] Alternatively, the coating layer may contain a metal compound. Here, examples of the metal include cobalt, aluminum, nickel, iron, manganese, titanium, zinc, lithium, carbon, etc. As an example of the metal compound, the coating layer may contain oxides, fluorides, etc. of these metals.

[0082] In the present embodiment, a carbon-containing layer is provided as the coating layer. As the carbon-containing layer, it is preferable to use graphene. Graphene has excellent electrical properties of having high conductivity, and excellent physical properties of having high flexibility and mechanical strength.

[0083] In this specification, graphene includes single-layer graphene or multilayer graphene having two or more and 100 or less single-layer graphene layers. Single-layer graphene refers to a sheet of a one-atom layer carbon molecule having a π bond. Further, graphene oxide refers to a compound obtained by oxidizing the above graphene. When graphene is formed by reducing graphene oxide, not all of the oxygen contained in graphene oxide is desorbed, and a part of the oxygen remains in the graphene. When graphene contains oxygen, the proportion of oxygen is 2 atomic% or more and 20 atomic% or less of the whole graphene when measured by X-ray photoelectron spectroscopy (XPS), preferably 3 atomic% or more and 15 atomic% or less.

[0084] The film thickness of the carbon-containing layer is preferably 1 nm or more and 50 nm or less.

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

[0086] Graphene oxide can be produced using various synthesis methods such as the Hummers method, the Modified Hummers method, or the oxidation of lead compounds. For example, the Hummers method is a technique for oxidizing graphite such as flaky graphite to form graphite oxide. The formed graphite oxide has functional groups such as carbonyl groups, carboxyl groups, and hydroxyl groups bonded thereto due to the oxidation of the graphite here and there, and the crystallinity of the graphite is impaired and the interlayer distance is increased. Therefore, the interlayer can be easily separated by ultrasonic treatment or the like to obtain graphene oxide.

[0087] For example, the Hummers method is a method of oxidizing graphite such as flaky graphite to form graphite oxide. The formed graphite oxide has functional groups such as carbonyl groups, carboxyl groups, and hydroxyl groups bonded thereto due to the oxidation of the graphite here and there, and the crystallinity of the graphite is impaired and the interlayer distance is increased. Therefore, the interlayer can be easily separated by ultrasonic treatment or the like to obtain graphene oxide. For example, the Hummers method is a technique for oxidizing graphite such as flaky graphite to form graphite oxide. The formed graphite oxide has functional groups such as carbonyl groups, carboxyl groups, and hydroxyl groups bonded thereto due to the oxidation of the graphite here and there, and the crystallinity of the graphite is impaired and the interlayer distance is increased. Therefore, the interlayer can be easily separated by ultrasonic treatment or the like to obtain graphene oxide. For example, the Hummers method is a method of oxidizing graphite such as flaky graphite to form graphite oxide. The formed graphite oxide has functional groups such as carbonyl groups, carboxyl groups, and hydroxyl groups bonded thereto due to the oxidation of the graphite here and there, and the crystallinity of the graphite is impaired and the interlayer distance is increased. Therefore, the interlayer can be easily separated by ultrasonic treatment or the like to obtain graphene oxide. For example, the Hummers method is a technique for oxidizing graphite such as flaky graphite to form graphite oxide. The formed graphite oxide has functional groups such as carbonyl groups, carboxyl groups, and hydroxyl groups bonded thereto due to the oxidation of the graphite here and there, and the crystallinity of the graphite is impaired and the interlayer distance is increased. Therefore, the interlayer can be easily separated by ultrasonic treatment or the like to obtain graphene oxide. For example, the Hummers method is a technique for oxidizing graphite such as flaky graphite to form graphite oxide. The formed graphite oxide has functional groups such as carbonyl groups, carboxyl groups, and hydroxyl groups bonded thereto due to the oxidation of the graphite here and there, and the crystallinity of the graphite is impaired and the interlayer distance is increased. Therefore, the interlayer can be easily separated by ultrasonic treatment or the like to obtain graphene oxide. For example, the Hummers method is a technique for oxidizing graphite such as flaky graphite to form graphite oxide. The formed graphite oxide has functional groups such as carbonyl groups, carboxyl groups, and hydroxyl groups bonded thereto due to the oxidation of the graphite here and there, and the crystallinity of the graphite is impaired and the interlayer distance is increased. Therefore, the interlayer can be easily separated by ultrasonic treatment or the like to obtain graphene oxide.

[0088] In addition, the length of one side of the graphene oxide (also referred to as the flake size) is 50 nm or more and 10 0 μm or less, preferably 800 nm or more and 20 μm or less. The larger the flake size, the more preferable it is because it is easier to cover the surface of the lithium manganese composite oxide. In addition, the length of one side of the graphene oxide (also referred to as the flake size) is 50 nm or more and 10

[0089] First, graphene oxide and water are put into a kneader to prepare a dispersion solution of graphene oxide. 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 However, when it exceeds 5 wt%, the electrode volume becomes bulky and the electrode weight becomes heavy.

[0090] Next, as shown in step S17 shown in FIG. 1, a lithium manganese composite oxide is put into the dispersion solution and kneaded. Note that kneading refers to kneading due to high viscosity. By performing kneading, aggregation of the lithium manganese composite oxide powder can be loosened, and graphene oxide and the lithium manganese composite oxide can be dispersed more uniformly. Next, as shown in step S17 shown in FIG. 1, a lithium manganese composite oxide is put into the dispersion solution and kneaded. Note that kneading refers to kneading due to high viscosity. By performing kneading, aggregation of the lithium manganese composite oxide powder can be loosened, and graphene oxide and the lithium manganese composite oxide can be dispersed more uniformly. Next, as shown in step S17 shown in FIG. 1, a lithium manganese composite oxide is put into the dispersion solution and kneaded. Note that kneading refers to kneading due to high viscosity. By performing kneading, aggregation of the lithium manganese composite oxide powder can be loosened, and graphene oxide and the lithium manganese composite oxide can be dispersed more uniformly. Next, as shown in step S17 shown in FIG. 1, a lithium manganese composite oxide is put into the dispersion solution and kneaded. Note that kneading refers to kneading due to high viscosity. By performing kneading, aggregation of the lithium manganese composite oxide powder can be loosened, and graphene oxide and the lithium manganese composite oxide can be dispersed more uniformly.

[0091] Next, after the mixture of graphene oxide and the lithium manganese composite oxide is dried under reduced pressure in a bell jar, it is crushed in a mortar to obtain a lithium manganese composite oxide coated with graphene oxide. Next, after the mixture of graphene oxide and the lithium manganese composite oxide is dried under reduced pressure in a bell jar, it is crushed in a mortar to obtain a lithium manganese composite oxide coated with graphene oxide. Next, after the mixture of graphene oxide and the lithium manganese composite oxide is dried under reduced pressure in a bell jar, it is crushed in a mortar to obtain a lithium manganese composite oxide coated with graphene oxide.

[0092] 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. 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. 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. 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.

[0093] 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 to form graphene. In addition, not all of the oxygen contained in graphene oxide is desorbed, and some oxygen may remain in the graphene. When graphene contains oxygen, the proportion of oxygen is 2 atomic% or more and 20 atomic% or less, preferably 3 atomic% or more and 15 atomic% or less of the entire graphene when measured by XPS. This reduction treatment is performed at room temperature or higher and 150°C or lower. 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 to form graphene. In addition, not all of the oxygen contained in graphene oxide is desorbed, and some oxygen may remain in the graphene. When graphene contains oxygen, the proportion of oxygen is 2 atomic% or more and 20 atomic% or less, preferably 3 atomic% or more and 15 atomic% or less of the entire graphene when measured by XPS. This reduction treatment is performed at room temperature or higher and 150°C or lower. 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 to form graphene. In addition, not all of the oxygen contained in graphene oxide is desorbed, and some oxygen may remain in the graphene. When graphene contains oxygen, the proportion of oxygen is 2 atomic% or more and 20 atomic% or less, preferably 3 atomic% or more and 15 atomic% or less of the entire graphene when measured by XPS. This reduction treatment is performed at room temperature or higher and 150°C or lower. 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 to form graphene. In addition, not all of the oxygen contained in graphene oxide is desorbed, and some oxygen may remain in the graphene. When graphene contains oxygen, the proportion of oxygen is 2 atomic% or more and 20 atomic% or less, preferably 3 atomic% or more and 15 atomic% or less of the entire graphene when measured by XPS. This reduction treatment is performed at room temperature or higher and 150°C or lower. 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 to form graphene. In addition, not all of the oxygen contained in graphene oxide is desorbed, and some oxygen may remain in the graphene. When graphene contains oxygen, the proportion of oxygen is 2 atomic% or more and 20 atomic% or less, preferably 3 atomic% or more and 15 atomic% or less of the entire graphene when measured by XPS. This reduction treatment is performed at room temperature or higher and 150°C or lower. 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 to form graphene. In addition, not all of the oxygen contained in graphene oxide is desorbed, and some oxygen may remain in the graphene. When graphene contains oxygen, the proportion of oxygen is 2 atomic% or more and 20 atomic% or less, preferably 3 atomic% or more and 15 atomic% or less of the entire graphene when measured by XPS. This reduction treatment is performed at room temperature or higher and 150°C or lower. , preferably at a temperature of not less than room temperature and not more than 80 °C. During the reduction treatment, heating can be carried out to promote the reduction reaction. Also, the reduction time of graphene oxide can be set to not less than 3 minutes and not more than 10 hours. By doing so, the reduction reaction can be promoted. Also, the reduction time of graphene oxide can be set to not less than 3 minutes and not more than 10 hours.

[0094] As the reducing agent, ascorbic acid, hydrazine, dimethylhydrazine, hydroquinone, sodium borohydride (NaBH4), tetrabutylammonium bromide (TBAB ), lithium aluminum hydride (LiAlH4), N,N-diethylhydroxylamine or derivatives thereof can be used. For example, ascorbic acid and hydro quinone are preferred in terms of high safety due to their weaker reducing power compared to hydrazine and sodium borohydride and ease of industrial use.

[0095] As the solvent, a polar solvent can be used. The material is not limited as long as it can dissolve the reducing agent. For example, water, methanol, ethanol, acetone, tetrahydro furan (THF), dimethylformamide (DMF), 1-methyl-2-pyrrolidone ( NMP) and dimethyl sulfoxide (DMSO), ethylene glycol, diethylene glycol or a mixed solution of any one or two or more of glycerin can be used.

[0096] 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, and lithium hydroxide will be described.

[0097] Reacting graphene oxide coated with lithium manganese composite oxide in a reducing solution Thereby, protons are added to the graphene oxide by ascorbic acid. Then, H2 O is desorbed, reducing the graphene oxide.

[0098] After the reduction treatment, as shown in step S19 in FIG. 1, powder recovery is performed. Here, filtration of the reducing solution is performed. The substance obtained here is referred to as substance A. For filtration, suction filtration or the like may be used. Or, substance A and the liquid may be separated using centrifugation.

[0099] Next, the obtained substance A is washed. The washing may be performed, for example, using a solvent listed as a solvent contained in the reducing solution. Note that it may be the same solvent as the solvent contained in the reducing solution, or a different solvent may be used.

[0100] Next, drying is performed. This drying step may be performed, for example, 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 longer and 48 hours or shorter. By this drying, polar solvents and moisture are evaporated or removed. Also in this drying step, the reduction of graphene oxide can be promoted. It may be performed under reduced pressure (vacuum) or in a reducing atmosphere, or may be performed at atmospheric pressure. Also, as the atmosphere during drying, air may be used, or nitrogen or other inert gases may be used.

[0101] Here, when substance A is particles, it is preferable that the particles form, for example, secondary particles.

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

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

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

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

[0106] Note that it is not necessary to desorb all the oxygen contained in graphene oxide, and some oxygen is contained in the g It may remain in the graphene. When oxygen is contained in the graphene, the ratio of oxygen is XP When measured by S, it is 2 atomic% or more and 20 atomic% or less of the whole graphene, preferably 3 atomic% or more and 15 atomic% or less.

[0107] By performing heat treatment after the reduction treatment, the electrical conductivity of the graphene obtained may be increased as compared with that before the heat treatment.

[0108] By performing heat treatment after the reduction treatment, for example, in the "particles having a lithium manganese composite oxide" of one aspect of the present invention, the first region to the third region may be formed. The first region to the third region of the "particles having a lithium manganese composite oxide" may be formed before the heat treatment. Alternatively, it may be formed during the heat treatment. Also for example, the thickness, composition, crystal structure, etc. of the first region to the third region formed before the formation of the coating layer, after the formation of the coating layer, and after the reduction treatment may change during the heat treatment.

[0109] Also, by performing heat treatment, for example, an element contained in the binder and a particle having a lithium manganese composite oxide may react. As an example, when PVd F is used as the binder, fluorine contained in PVdF and any one or more of lithium, manganese, and element M of the particle having a lithium manganese composite oxide may form a metal fluoride.

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

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

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

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

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

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

[0116] The second region is in contact with at least a part of the surface of the first region and is outside the first region​​​ is located. Here, the outer side indicates being closer to the surface of the particle. The third region preferably contacts at least a part of the surface of the second region and is located outside the second region. .

[0117] Also, when the second region has a layered region, for example, its thickness is preferably 0.1 nm or more and 30 nm or less, and more preferably 1 nm or more and 15 nm or less.

[0118] 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.

[0119] Also, it is more preferable that the first region and the second region contain both manganese and element M. .

[0120] Also, the third region preferably includes the surface of the particles having a lithium manganese composite oxide which is one aspect of the present invention.

[0121] Also, when the third region has a layered region, for example, its thickness is preferably 0.1 nm or more and 30 nm or less, more preferably 1 nm or more and 20 nm or less, and even more preferably 2 nm or more and 10 nm or less.

[0122] Fig. 2(A) shows an example in which the particle has region 131 as the first region, region 132 as the second region, and region 133 as the third region.

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

[0124] Further, as shown in FIG. 2(B), region 131 may have a region not covered by region 132. Also, region 132 may have a region not covered by region 133. Further, for example, region 131 may have a region in contact with region 133. Also, region 131 may have a region not covered by either of region 13 2 and region 133.

[0125] When a power storage device is manufactured using particles having a lithium manganese composite oxide, which is one aspect of the present invention, for battery reactions such as charging and discharging, the third region is preferably more stable compared to the first region and the second region.

[0126] Here, the second region may have a crystal structure different from that of the first region. Or, the second region may have crystals with a different orientation from those of the first region.

[0127] 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.

[0128] Or, for example, the first region and the second region have a layered rock salt-type structure, and the first plane of the crystal of the region and the second plane of the crystal of the second region are parallel to each other. This is preferable.

[0129] Here, when the first plane is the {0 0 1} plane of the layered rock salt-type structure, the {0 0 1} plane of the layered rock salt-type structure is preferably parallel to at least one of the {1 0 0} plane, {1 3 -1} plane or {-1 3 1} plane of the crystal of the second region. Also ​When the first surface is the {1 0 0} surface of the layered rock salt structure, the {1 0 0} surface of the layered rock salt structure is preferably parallel to at least one of the {0 0 1} surface, the {1 3 -1} surface, or the {-1 3 1} surface of the crystal in the second region. Or, when the first surface is the {1 3 -1} surface of the layered rock salt structure, the {1 3 -1 } surface of the layered rock salt structure is preferably parallel to at least one of the {0 0 1} surface, the {1 0 0} surface, or the {-1 3 1} surface of the crystal in the second region. Or, when the first surface is the {-1 3 1} surface of the layered rock salt structure, the {-1 3 1} surface of the layered rock salt structure is preferably parallel to at least one of the {0 0 1} surface, the {1 0 0} surface, or the {1 3 -1} surface of the crystal in the second region.

[0130] Also, for example, the first region and the second region have a layered rock salt structure, and the first orientation of the crystal in the region and the second orientation of the crystal in the second region are parallel, which is preferable. Here, the crystal orientation of the crystal in the first region and the crystal in the second region will be explained.

[0131] Here, three crystal orientations of <1 0 0>, <1 1 0>, and <-1 1 0> are set as the first group. Also, <0 0 1>, <0 1 1>, and <0 1 -1> are set as the second group and <-3 2 3>, <3 1 6>, and <6 -1 3> are set as the third group. Also, <3 2 -3>, <3 -1 6>, and <6 1 3> are set as the fourth group.

[0132] The crystal in the first region is selected from any one of the first group to the fourth group. It has an orientation. The crystal in the second region is selected from one of the three groups other than the group having the orientation of the crystal in the first region among the first to fourth groups, and has any orientation selected therefrom. For an example of the above combination, a specific example will be given and described below. Here, the (001) plane and the (100) plane will be described. In the following, for the sake of specific description, a notation method of indices without considering the symmetry of the crystal will be adopted.

[0133] Regarding an example of the above combination, a specific example will be given and described below. Here, the (001 ) plane and the (100) plane will be described. In the following, for the sake of specific description, a notation method of indices without considering the symmetry of the crystal will be adopted.

[0134] Fig. 3 shows a view of the crystal structure of Li2MnO3 as seen from the negative direction of the b-axis. Here, Fig. 4(A) shows a view of the layers A-1 and A-2 in the region surrounded by the broken line A shown in Fig. 3, as seen from the side of layer A-2 and in a direction perpendicular to layers A-1 and A-2. Here, layer A-1 has oxygen, and layer A-2 has lithium and manganese.

[0135] Also, Fig. 4(B) shows a view of the layers B-1 and B-2 in the region surrounded by the broken line B shown in Fig. 3, as seen from the side of layer B-2 and in a direction perpendicular to layers B-1 and B-2.

[0136] In Fig. 4(A), lithium or manganese is stacked shifted in the

[0110] direction or the [-100] direction or the [1-10] direction on top of the oxygen atoms. Similarly, in Fig. 4(B), lithium or manganese is stacked shifted in the [0-11] direction or the [00-1] direction or the

[0011] direction on top of the hexagonal structure formed by oxygen. Also, in the region surrounded by the broken line in Fig. 4(A), when manganese is changed to lithium, the configuration is the same as that in Fig. 4(B). That is, although the types of metal atoms are different, the positions of the metal atoms roughly coincide. These ​​​​​​​​​Therefore, the two structures have many common points and are considered to have good consistency when stacked.

[0137] Further, the second region preferably has a composition different from that of the first region.

[0138] 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, ma nganese, element M, and oxygen in the second region are represented by a2:b2:c2:d2, the case 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÷( b2 + 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.

[0139] Further, 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.

[0140] 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 as well.

[0141] Further, 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 crystal ​It is a region where the structure changes continuously or stepwise. Alternatively, the transition layer refers to the crystal lattice It is a region where the constants change continuously or stepwise.

[0142] Alternatively, a mixed layer may be provided between the second region and the first region. Here, the mixed layer refers to, for example, a layer in which two or more crystals having different crystal orientations are mixed. Alternatively, the mixed layer refers to, for example, a layer in which two or more crystals having different crystal structures are mixed. Alternatively, the mixed layer refers to, for example, a layer in which two or more crystals having different compositions are mixed.

[0143] 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 .

[0144] Here, for example, when manufacturing a rechargeable 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 rechargeable battery is manufactured.

[0145] For example, the first region to the third region 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. 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.

[0146] Also, the first region to the third region may be formed during the heat treatment in each step of manufacturing a rechargeable battery or the like.

[0147] In the process of manufacturing the lithium manganese composite oxide, as shown in S15, the primary particles are sintered The pulverization process of the lithium manganese composite oxide is an important process that affects the characteristics of the battery. In the pulverization process, the lithium manganese composite oxide in which the primary particles are sintered is subjected to shear (stress of crushing) to form powdered lithium manganese composite oxide. At this time, when the lithium manganese composite oxide has a layered rock salt-type crystal structure, the primary particles may split and crack on the plane parallel to the layer or the plane perpendicular to the layer. In this specification, etc., the primary particles that have split and cracked are called particles having a cleavage plane or particles with an exposed cleavage plane. Note that the cracked primary particles also include those without a cleavage plane. Also, when using particles having cleavage properties, such as a lithium manganese composite oxide having a layered rock salt-type crystal structure, as the active material, not only during the pulverization process but also in the electrode manufacturing process, when pressure is applied to the electrode for molding, the active material layer is pressurized, and the active material may crack further. In addition, when manufacturing a wound-type battery, a large stress acts during the winding of the electrode. Also, even when the wound body of the electrode is housed in a casing, a stress always acts toward the outside of the winding axis, so there is a risk that the active material will crack further. As described above, if the primary particles of the lithium manganese composite oxide, which is the active material, split and crack, it will cause a decrease in the discharge capacity and cycle characteristics of the battery. Even in such a case, on the cleavage plane of the lithium manganese composite oxide, a layer containing carbon is

[0148] formed. formed. formed. formed.

[0149] In addition, when manufacturing a wound-type battery, a large stress acts during the winding of the electrode. Also, even when the wound body of the electrode is housed in a casing, a stress always acts toward the outside of the winding axis, so there is a risk that the active material will crack further. In addition, when manufacturing a wound-type battery, a large stress acts during the winding of the electrode. Also, even when the wound body of the electrode is housed in a casing, a stress always acts toward the outside of the winding axis, so there is a risk that the active material will crack further. In addition, when manufacturing a wound-type battery, a large stress acts during the winding of the electrode. Also, even when the wound body of the electrode is housed in a casing, a stress always acts toward the outside of the winding axis, so there is a risk that the active material will crack further.

[0150] As described above, if the primary particles of the lithium manganese composite oxide, which is the active material, split and crack, it will cause a decrease in the discharge capacity and cycle characteristics of the battery. As described above, if the primary particles of the lithium manganese composite oxide, which is the active material, split and crack, it will cause a decrease in the discharge capacity and cycle characteristics of the battery.

[0151] Even in such a case, on the cleavage plane of the lithium manganese composite oxide, a layer containing carbon is It is preferably provided. Further, the carbon-containing layer may cover all of the cleavage planes or may cover the entire lithium manganese composite oxide having the cleavage planes. Here, the cleavage plane includes, for example, the plane exposed by cleavage. For example, it includes the plane exposed by cleavage. For example, it includes the plane exposed by cleavage.

[0152] In one aspect of the present invention, graphene is formed so as to cover the lithium manganese composite oxide. Graphene may be provided on the entire surface of the lithium manganese composite oxide or may be provided only on a part thereof. Further, in the particles, it is preferable that graphene is formed so as to cover the exposed cleavage plane. Further, it is sufficient that graphene is provided on at least a part of the cleavage plane of the lithium manganese composite oxide. By using the active material covered with graphene on at least a part of the cleavage plane as an 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 accompanying charge and discharge can be improved. In one aspect of the present invention, graphene is formed so as to cover the lithium manganese composite oxide. Graphene may be provided on the entire surface of the lithium manganese composite oxide or may be provided only on a part thereof. Further, in the particles, it is preferable that graphene is formed so as to cover the exposed cleavage plane. Further, it is sufficient that graphene is provided on at least a part of the cleavage plane of the lithium manganese composite oxide. By using the active material covered with graphene on at least a part of the cleavage plane as an 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 accompanying charge and discharge can be improved. In one aspect of the present invention, graphene is formed so as to cover the lithium manganese composite oxide. Graphene may be provided on the entire surface of the lithium manganese composite oxide or may be provided only on a part thereof. Further, in the particles, it is preferable that graphene is formed so as to cover the exposed cleavage plane. Further, it is sufficient that graphene is provided on at least a part of the cleavage plane of the lithium manganese composite oxide. By using the active material covered with graphene on at least a part of the cleavage plane as an 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 accompanying charge and discharge can be improved. In one aspect of the present invention, graphene is formed so as to cover the lithium manganese composite oxide. Graphene may be provided on the entire surface of the lithium manganese composite oxide or may be provided only on a part thereof. Further, in the particles, it is preferable that graphene is formed so as to cover the exposed cleavage plane. Further, it is sufficient that graphene is provided on at least a part of the cleavage plane of the lithium manganese composite oxide. By using the active material covered with graphene on at least a part of the cleavage plane as an 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 accompanying charge and discharge can be improved. In one aspect of the present invention, graphene is formed so as to cover the lithium manganese composite oxide. Graphene may be provided on the entire surface of the lithium manganese composite oxide or may be provided only on a part thereof. Further, in the particles, it is preferable that graphene is formed so as to cover the exposed cleavage plane. Further, it is sufficient that graphene is provided on at least a part of the cleavage plane of the lithium manganese composite oxide. By using the active material covered with graphene on at least a part of the cleavage plane as an 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 accompanying charge and discharge can be improved. In one aspect of the present invention, graphene is formed so as to cover the lithium manganese composite oxide. Graphene may be provided on the entire surface of the lithium manganese composite oxide or may be provided only on a part thereof. Further, in the particles, it is preferable that graphene is formed so as to cover the exposed cleavage plane. Further, it is sufficient that graphene is provided on at least a part of the cleavage plane of the lithium manganese composite oxide. By using the active material covered with graphene on at least a part of the cleavage plane as an 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 accompanying charge and discharge can be improved. In one aspect of the present invention, graphene is formed so as to cover the lithium manganese composite oxide. Graphene may be provided on the entire surface of the lithium manganese composite oxide or may be provided only on a part thereof. Further, in the particles, it is preferable that graphene is formed so as to cover the exposed cleavage plane. Further, it is sufficient that graphene is provided on at least a part of the cleavage plane of the lithium manganese composite oxide. By using the active material covered with graphene on at least a part of the cleavage plane as an 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 accompanying charge and discharge can be improved. In one aspect of the present invention, graphene is formed so as to cover the lithium manganese composite oxide. Graphene may be provided on the entire surface of the lithium manganese composite oxide or may be provided only on a part thereof. Further, in the particles, it is preferable that graphene is formed so as to cover the exposed cleavage plane. Further, it is sufficient that graphene is provided on at least a part of the cleavage plane of the lithium manganese composite oxide. By using the active material covered with graphene on at least a part of the cleavage plane as an 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 accompanying charge and discharge can be improved.

[0153] Graphene has excellent physical properties such as high flexibility and mechanical strength. Therefore, by using the electrode containing the active material in a battery, even if the lithium manganese composite oxide expands and contracts as the battery repeats charge and discharge, it is possible to prevent the lithium manganese composite oxide from further cleaving and cracking due to volume change. Graphene has excellent physical properties such as high flexibility and mechanical strength. Therefore, by using the electrode containing the active material in a battery, even if the lithium manganese composite oxide expands and contracts as the battery repeats charge and discharge, it is possible to prevent the lithium manganese composite oxide from further cleaving and cracking due to volume change. Graphene has excellent physical properties such as high flexibility and mechanical strength. Therefore, by using the electrode containing the active material in a battery, even if the lithium manganese composite oxide expands and contracts as the battery repeats charge and discharge, it is possible to prevent the lithium manganese composite oxide from further cleaving and cracking due to volume change. Graphene has excellent physical properties such as high flexibility and mechanical strength. Therefore, by using the electrode containing the active material in a battery, even if the lithium manganese composite oxide expands and contracts as the battery repeats charge and discharge, it is possible to prevent the lithium manganese composite oxide from further cleaving and cracking due to volume change.

[0154] Further, in the electrode manufacturing process, when pressure is applied to the electrode for molding, the pressure applied to the lithium manganese composite oxide can be relaxed by the mechanical strength of graphene. Thereby, it is possible to prevent the lithium manganese composite oxide from further cleaving and cracking. Further, in the electrode manufacturing process, when pressure is applied to the electrode for molding, the pressure applied to the lithium manganese composite oxide can be relaxed by the mechanical strength of graphene. Thereby, it is possible to prevent the lithium manganese composite oxide from further cleaving and cracking. Further, in the electrode manufacturing process, when pressure is applied to the electrode for molding, the pressure applied to the lithium manganese composite oxide can be relaxed by the mechanical strength of graphene. Thereby, it is possible to prevent the lithium manganese composite oxide from further cleaving and cracking. Further, in the electrode manufacturing process, when pressure is applied to the electrode for molding, the pressure applied to the lithium manganese composite oxide can be relaxed by the mechanical strength of graphene. Thereby, it is possible to prevent the lithium manganese composite oxide from further cleaving and cracking.

[0155] Furthermore, in a wound-type battery, when a large stress acts during winding of the electrode, or when the wound body is housed in the casing, assuming that a stress always acts on the electrode toward the outside of the winding axis it is possible to prevent the lithium manganese composite oxide from further splitting and cracking.

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

[0157] FIG. 5(A) is a plan view of the electrode 100, and FIG. 5(B) is a cross-sectional view of the portion enclosed by the broken line in FIG. 5(A). The electrode 100 has a structure in which an active material layer 102 is provided on a current collector 101. In FIG. 5(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.

[0158] The current collector 101 is not particularly limited 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, neodymium, titanium, tantalum, manganese, and alloys thereof, and sintered carbon can be used. Also, copper or stainless steel may be coated with carbon, nickel, titanium, etc. Furthermore, an aluminum alloy added with an element for improving heat resistance such as silicon, neodymium, scandium, molybdenum can be used. Also, it may be formed of a metal element capable of reacting with silicon to form a silicide. Examples of the metal element that reacts with silicon to form a silicide include zirconium, titanium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, cobalt, nickel, etc. ​​​​​Moreover, the current collector 101 can be in various forms such as foil, plate (sheet), net, column, coil, punched metal, expanded metal, porous, and non-woven fabric. And various shapes can be appropriately used. Further, in order to improve the adhesion with the active material layer, the current collector 101 may have fine irregularities on its surface. Also, it is preferable to use a current collector 101 with a thickness of 5 μm or more and 30 μm or less.

[0159] The active material layer 102 contains an active material. The active material refers only to a substance involved in the insertion and extraction of ions that are carriers. However, in this specification and the like, in addition to the material that is originally an "active material", those including a conductive aid, a binder, etc. are also referred to as the active material layer.

[0160] When using a negative electrode active material as the active material, for example, carbon-based materials, alloy-based materials, etc. can be used.

[0161] As the carbon-based materials, there are graphite, graphitizable carbon (soft carbon), non-graphitizable carbon (hard carbon), carbon nanotubes, graphene, carbon black, etc.

[0162] As the graphite, there are artificial graphite such as mesocarbon microbeads (MCMB), coke-based artificial graphite, pitch-based artificial graphite, etc., and natural graphite such as spheroidized natural graphite.

[0163] When lithium ions are inserted into graphite (when forming a lithium-graphite intercalation compound), the potential shows a relatively low potential similar to that of lithium metal (0.1 V or more and 0.3 V or less vs. Li / Li). i + As a result, the lithium-ion secondary battery can show a high operating voltage. Further, In this regard, graphite is preferable because it has advantages such as a relatively high capacity per unit volume, small volume expansion, low cost, and high safety compared to lithium metal.

[0164] As the negative electrode active material, an alloying material can be used. Here, as the alloying material, a material capable of performing charge and discharge reactions by forming an alloy with a metal that becomes a carrier ion can also be used. For example, a material containing at least one of Ga, Si, Al, Ge, Sn, Pb, Sb, Bi, Ag, Zn, Cd, In, etc. can be used. Such elements have a larger capacity than carbon. In particular, silicon has a high theoretical capacity of 4200 mAh / g, so that the capacity of the power storage device can be increased. Examples of alloy-based materials using such elements include SiO, Mg2Si, Mg2Ge, SnO, SnO2, Mg2Sn, SnS2, V2Sn3, FeSn2, CoSn2, Ni3Sn2, Cu6Sn5, Ag3Sn, Ag3Sb, Ni2MnSb, CeSb3, LaSn3, La3Co2Sn7, CoSb3, InSb, SbSn, etc.

[0165] Here, in order to increase the capacity of the power storage device, it is particularly preferable to use a material containing silicon, such as silicon or SiO, as the negative electrode active material. Here, SiO is a compound containing silicon and oxygen. When the atomic ratio of silicon to oxygen is silicon:oxygen = α:β, α preferably has a value near β. Here, having a value near means that, for example, the absolute value of the difference between α and β is preferably 20% or less, more preferably 10% or less, with respect to the value of β.

[0166] ​​​​​​​​​​In addition, titanium dioxide (TiO2) and lithium titanium oxide (Li4 Ti5O 12 ), lithium-graphite intercalation compound (Li x C6), niobium pentoxide (Nb2O5 ), tungsten oxide (WO2), molybdenum oxide (MoO2), etc. can be done.

[0167] In addition, the negative electrode active material is a composite nitride of lithium and transition metals, which has a Li3N structure. Li 3-x M x N (M=Co, Ni, Cu) can be used. For example, Li 2. 6Co 0.4 N3 has a large charge / discharge capacity (900mAh / g, 1890mAh / cm 3 )of This is preferable.

[0168] When a composite nitride of lithium and transition metals is used, the negative electrode active material contains lithium ions, In addition, materials that do not contain lithium ions, such as V2O5 and Cr3O8, are used as the positive electrode active material. In addition, when a material containing lithium ions is used as the positive electrode active material, However, by first removing the lithium ions contained in the positive electrode active material, As the lithium-transition metal nitride, a complex nitride of lithium and a transition metal can be used.

[0169] In addition, a material that undergoes a conversion reaction can be used as the negative electrode active material. For example, lithium oxide such as cobalt oxide (CoO), nickel oxide (NiO), and iron oxide (FeO) A transition metal oxide that does not undergo an alloying reaction with the metal may be used as the negative electrode active material. Further materials that can cause reactions include Fe2O3, CuO, Cu2O, RuO2, Cr2 Oxides such as O3, CoS 0.89, sulfides such as NiS and CuS, Zn3N2, Cu3N, nitrides such as Ge3N4, phosphides such as NiP2, FeP2, and CoP3, FeF3, BiF 3, etc., also occur with fluorides.

[0170] When using a positive electrode active material as the active material, as the positive electrode active material, a material capable of inserting and desorbing lithium ions can be used. For example, a material 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. can.

[0171] 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 also be used. Examples of other active materials include, for example, LiFeO2, LiCoO2, LiNiO2, LiMn2O4, V2O5, Cr2 O5, MnO2, etc. can be used as materials.

[0172] 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 Li MPO4 include LiFePO4, LiNiPO4, LiCoPO4, LiM nPO4, LiFe a Ni b PO4, LiFe a Co b PO4, LiFe a Mn b PO4 , LiNi a Co b PO4, LiNi a Mn b PO4 (a + b is 1 or less, 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 is 1 or less, 0 < c < 1, 0 < d < 1, 0 < e < 1), LiFe f Ni g Co h Mn i PO4 (where f + g + h + i is 1 or less, 0 < f < 1, 0 < g < 1, 0 < h < 1, 0 < i < 1), etc. Lithium metal phosphate compounds such as these can be mentioned.

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

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

[0175] Note that the carrier ion is an alkali metal ion other than lithium ion, alkaline earth metal In the case of group I ions, as the positive electrode active material, compounds in which lithium in the above lithium compound, lithium-containing composite phosphate salt and lithium-containing composite silicate is substituted with a carrier such as an alkali metal (e.g., sodium lithium, potassium, etc.), alkaline earth metal (e.g., calcium, strontium, barium ium, beryllium, magnesium, etc.) may be used.

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

[0177] Further, the active material layer 102 may contain a conductive assistant. As the conductive assistant, for example, natural graphite , artificial graphite such as mesocarbon microbeads, carbon fiber, etc. can be used. Carbon fiber, for example, carbon fiber such as mesophase pitch-based carbon fiber, isotropic pitch-based carbon fiber, etc. can be used. Further, as the carbon fiber, carbon nanofiber, carbon nanotube, etc. can be used. Carbon nanotube can be produced, for example, by a vapor phase growth method . Further, as the conductive assistant, for example, carbon materials such as carbon black (acetylene black (AB), etc.) or graphene can be used. Further, for example, metal powders such as copper, nickel, aluminum, silver, gold, etc., metal fibers, conductive ceramics x materials, etc. can be used.

[0178] Flaky graphene has excellent electrical properties such as high conductivity, and excellent physical properties such as flexibility and mechanical strength. Therefore, by using graphene as a conductive assistant , the contact points and contact areas between the active materials can be increased.

[0179] The active material layer 102 preferably has a binder, and the binder is a water-soluble polymer. More preferably, it has a binder. Further, the active material layer 102 may have a plurality of types of binders. It is also good.

[0180] Examples of the binder include polyvinylidene fluoride (PVdF), polystyrene, polymethyl acrylate, polymethyl methacrylate (PMMA), sodium polyacrylate, polyvinyl alcohol (PVA), polyethylene oxide (PEO), polypropylene oxide, polyimide (PI), polyvinyl chloride, polytetrafluoroethylene, polyethylene, polypropylene, isobutylene, polyethylene terephthalate, nylon, polyacrylonitrile (PAN), and the like. It is preferable to use such materials. Moreover, as the binder, rubber materials such as styrene-butadiene rubber (SBR), styrene-isoprene-styrene rubber, acrylonitrile-butadiene rubber, butadiene rubber, and 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 resistant to stress caused by the expansion and contraction of the active material during charge and discharge, and the bending of the electrode, etc., and a highly reliable electrode can be obtained. On the other hand, they may have a hydrophobic group and be insoluble in water. In such a case, since the particles are dispersed in a state where they do not dissolve 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 (also referred to as an electrode binder composition) 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, an effect of moderately increasing the viscosity of the solution can be expected.

[0181] 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. These rubber materials are more preferably used in combination with a water-soluble polymer. These rubber materials have rubber elasticity and are easy to stretch and contract. Therefore, they are resistant to stress caused by the expansion and contraction of the active material during charge and discharge, and the bending of the electrode, etc., and a highly reliable electrode can be obtained. On the other hand, they may have a hydrophobic group and be insoluble in water. In such a case, since the particles are dispersed in a state where they do not dissolve 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 (also referred to as an electrode binder composition) 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, an effect of moderately increasing the viscosity of the solution can be expected. and are strong against stress, and a highly reliable electrode can be obtained. However, they may have a hydrophobic group and be insoluble in water. In such a case, since the particles are dispersed in a state where they do not dissolve 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 composition) to a viscosity suitable for coating. In this case, when a water-soluble polymer with a high viscosity adjusting function, such as a polysaccharide, is used, an effect of moderately increasing the viscosity of the solution can be expected. For example, when a polysaccharide is used, an effect of moderately increasing the viscosity of the solution can be expected.​​​​ Moreover, it can be uniformly dispersed with the rubber material to obtain a good electrode with high uniformity, for example, an electrode with high uniformity in electrode film thickness or electrode resistance.

[0182] As the water-soluble polymer, for example, polysaccharides can be used. As the polysaccharides, carboxymethyl cellulose (CMC), methyl cellulose, ethyl cellulose, hydroxy propyl cellulose and diacetyl cellulose, cellulose derivatives such as regenerated cellulose, starch, etc. can be used.

[0183] The binders may be used alone or in combination of two or more. Yes.

[0184] <Method for manufacturing electrode> Next, a method for manufacturing the electrode 100 according to one aspect of the present invention will be described.

[0185] First, an electrode mixture composition is prepared. The electrode mixture composition can be prepared, for example, by using the above-described active material, adding a binder, a conductive aid, etc., and kneading with a solvent. . The electrode mixture composition may be in the form of a slurry or a paste. As the solvent, for example, water, NMP (N-methyl-2-pyrrolidone), etc. can be used. From the viewpoints of safety and cost, it is preferable to use water.

[0186] As an example, the case where the electrode 100 is a positive electrode for a storage battery will be described. Here, as the active material, the active material according to one aspect of the present invention is used, acetylene black is used as the conductive aid, and PVdF is used as the binder. An example using NMP as the solvent will be described.

[0187] First, a cathode active material according to one embodiment of the present invention, acetylene black, and polyvinylidene fluoride are mixed together. NMP is added to these mixtures until a predetermined viscosity is reached, and kneaded to form an electrode binder composition. In this step, kneading and addition of a polar solvent may be repeated a plurality of times. The electrode binder composition may be in the form of a slurry or a paste.

[0188] Through the above steps, an electrode binder composition with a uniform dispersion state of the cathode active material, conductive assistant, and binder can be formed.

[0189] 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 cathode active material layer. As the undercoat, for example, a carbon layer, a metal layer, a layer containing carbon and a polymer, and a layer containing a metal and a polymer can be used. By forming an undercoat on the current collector, the contact resistance between the current collector and the subsequently formed cathode active material layer can be reduced. Also, the adhesion between the current collector and the cathode active material layer can be enhanced. When graphene is used as the conductive assistant, it is preferable that the undercoat does not dissolve in the reducing solution in the reduction process of graphene oxide. For example, a dispersion aqueous solution of graphite or acetylene black, or a mixture obtained by mixing a polymer into the aqueous solution can be used as the undercoat. For example, a mixture of graphite and sodium polyacrylate (PAA), or a mixture of AB and PVdF can be used. Also, the weight ratio of graphite to PAA is from graphite:PAA = 95:5 to 50:

[0190] In the range of 50, the mixing ratio of AB and PVdF may be in the range of AB:PVdF = 70:30 to 50:50. It is sufficient to be in this range.

[0191] In addition, if there are no problems with the adhesion between the active material layer and the current collector, electrode strength, and contact resistance, the under -coat does not necessarily need to be formed on the current collector.

[0192] Next, the slurry is provided on one side or both sides of the current collector by a coating method such as the doctor blade method. It is provided by any of these methods.

[0193] Next, the slurry provided on the current collector is dried by a method such as ventilation drying or reduced pressure (vacuum) drying to form an active material layer. This drying may be performed, for example, using hot air at 50°C or higher and 180°C or lower. By this step, the polar solvent contained in the active material layer is evaporated. The atmosphere is not particularly limited.

[0194] 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 the roll press method or the flat plate press method. Also, when performing the press, by applying heat at 90°C or higher and 18 0°C or lower, preferably 120°C or lower, the binder (for example, PVdF) contained in the undercoat and the active material layer is softened to such an extent that the characteristics of the electrode are not changed to further enhance the adhesion between the current collector and the active material layer.

[0195] Next, a heat treatment is performed on the active material layer to evaporate the solvent. The heat treatment may be performed under reduced pressure (vacuum) or in a reducing atmosphere. This heat treatment step is, for example, at 50°C or higher and 600°C or lower , more preferably 120°C or higher and 500°C or lower, and even more preferably 200°C or higher and 400°C It is preferably carried out at the following temperature for 1 hour or more and 48 hours or less. By this heat treatment, the polar solvent and moisture present in the active material layer are evaporated or removed.

[0196] Here, for example, when an electrode is produced using "particles having a lithium manganese composite oxide" of one embodiment of the present invention, and a storage battery is produced using the electrode, the first region to the third region of the "particles having a lithium manganese composite oxide" may be formed in any of the production process of the "particles having a lithium manganese composite oxide" and the production process of the storage battery. The first region to the third region of the "particles having a lithium manganese composite oxide" may be formed in any of the production process of the "particles having a lithium manganese composite oxide" and the production process of the storage battery. It may also be formed in any of the production process of the "particles having a lithium manganese composite oxide" and the production process of the storage battery.

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

[0198] Note that the first region to the third region of the "particles having a lithium manganese composite oxide" may be formed before the production of the electrode, for example, after the synthesis of the particles. Alternatively, it may be formed during the process of forming the electrode. Moreover, for example, the thickness, composition, crystal structure, etc. of the first region to the third region formed after the synthesis of the particles may change during the process of forming the electrode. In addition, the first region to the third region may be formed during the heat treatment of each step of producing a storage battery or the like. It may be formed during the heat treatment of each step of producing a storage battery or the like.

[0199] In addition, by performing heat treatment, for example, an element contained in the binder and an element contained in the particles having a lithium manganese composite oxide may react with each other. As an example, the case where PVdF is used as the binder will be described. PVdF is a polymer compound having fluorine. As an example, the case where PVdF is used as the binder will be described. PVdF is a polymer compound having fluorine. PVdF is a polymer compound having fluorine. . By using a polymer compound having fluorine as a binder, a bond may be formed between fluorine and an element contained in other materials constituting the electrode, such as an active material, a conductive assistant, a current collector, etc. Here, having a bond refers to, for example, a bond state that can be observed by analysis using XPS or the like. Or, having a bond means, for example, having a material having such a bond. Further, examples of materials having such a bond include metal fluorides. As the metal fluoride, for example, a metal fluoride of lithium, manganese, and element M, which is the metal contained in the lithium manganese composite oxide of one embodiment of the present invention, may be formed. Or, there may be a possibility of forming a bond with the metal used for the current collector. Or, for example, as an example of a coating layer of lithium manganese composite oxide, a layer containing carbon is shown here, but a bond may be formed between an element contained in the coating layer and fluorine. For example, when a layer containing carbon is used as the coating layer, carbon fluoride may be formed. Here, the coating layer may contain a third region of "particles having lithium manganese composite oxide", or may have a third region and a part of the first region or the second region. Further, the second region of "particles having lithium manganese composite oxide" may have a part of the coating layer, for example. By forming such a bond, for example, the strength of the electrode may be further increased. Or, by forming a bond in advance, for example, when a storage battery is manufactured, an irreversible reaction may be suppressed during charge and discharge of the storage battery. Further, by charge and discharge,

[0200]

[0201] ​​​​​​​​​​​​​​​In addition, the volume of the active material may change, which may cause a decrease in the strength of the electrode. When the strength of the electrode decreases, for example, the adhesion between the active materials or between the active material and the conductive assistant decreases. Therefore, the conductive paths of the electrode decrease, which may lead to a reduction in capacity. In such a case, by forming such a bond the strength of the electrode can be improved, and the resistance of the electrode to volume changes may be improved. There may be cases.

[0202] 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.

[0203] In addition, as the atmosphere for the heat treatment, gases such as oxygen, air, nitrogen, and rare gases can be used. The heat treatment may be performed under atmospheric pressure or under reduced pressure. Here, for example, by using a gas containing oxygen the reaction between each material constituting the electrode, for example, particles having a lithium manganese composite oxide and the 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. This refers to such a situation. In addition, by using an inert gas such as nitrogen or a rare gas, each of the materials constituting the electrode such as the current collector can be prevented from being deteriorated in some cases. Also, by performing the heat treatment under reduced pressure each of the materials constituting the electrode, such as the current collector, can be prevented from being deteriorated in some cases. When the heat treatment temperature is too high, decomposition or the like of each material constituting the electrode may occur. There may be cases.

[0204] Here, when the heat treatment temperature is too high, decomposition or the like of each material constituting the electrode may occur. Yes. 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 preferably 600 ° C or lower, more preferably 500 ° C or lower, and even more preferably 400 ° C or lower.

[0205] <Press> 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 ° 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 or 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.

[0206] Finally, the electrode is manufactured by punching out the current collector and the active material layer to a predetermined size.

[0207] In addition, in this embodiment, one aspect of the present invention has been described. Or, in other embodiments, one aspect of the present invention is described. However, one aspect of the present invention is not limited to these. That is, in this embodiment and other embodiments, various aspects of the invention are described Therefore, one aspect of the present invention is not limited to a specific aspect. For example, as one aspect of the present invention, an example when applied to a lithium ion secondary battery is shown, but one aspect of the present invention is not limited to this. Depending on the case or the situation, one aspect of the present invention may be various secondary batteries, lead storage batteries, lithium ion polymer secondary batteries, nickel-hydrogen storage batteries, nickel Ruthenium-cadmium battery, nickel-iron battery, nickel-zinc battery, silver oxide-zinc battery, solid battery, air battery, primary battery, capacitor, or lithium-ion capacitor, etc. may be applied. Or for example, in some cases, or depending on the situation, one aspect of the present invention may not be applied to a lithium-ion secondary battery. Also, as one aspect of the present invention, although an example where the active material has graphene or graphene oxide has been shown, one aspect of the present invention is not limited to this. In some cases, or depending on the situation, in one aspect of the present invention, graphene or graphene oxide is used as an electrode for a supercapacitor (electric double layer capacitor) which is a capacitor with a very large capacitance, used as an oxygen reduction electrode catalyst, used as a material for dispersion water with lower friction than lubricating oil, used as a transparent electrode for display devices, solar cells, etc., used as a gas barrier material, used as a polymer material with high mechanical strength and low weight, used as a material for a highly sensitive nanosensor for detecting uranium or plutonium contained in radioactive contaminated water, or used as a material for removing radioactive substances.

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

[0209] (Embodiment 2) In this embodiment, an example of a power storage device using an electrode which is one aspect of the present invention is shown.

[0210] In this specification etc., the power storage device refers to elements and devices in general having a power storage function. For example, it includes power storage batteries such as lithium-ion secondary batteries, lithium-ion capacitors, and electric double layer capacitors, etc. ​​​​​​

[0211] <Thin battery> Fig. 6 shows an example of a thin battery as a power storage device. The thin battery can be mounted on an electronic device having at least a part of a flexible portion if it has a flexible configuration, and the battery can also be bent according to the deformation of the electronic device. If it has a flexible configuration, it can be mounted on an electronic device having at least a part of a flexible portion, and the battery can also be bent according to the deformation of the electronic device. If it has a flexible configuration, it can be mounted on an electronic device having at least a part of a flexible portion, and the battery can also be bent according to the deformation of the electronic device.

[0212] Fig. 6 shows an external view of the thin battery 500. Figs. 7(A) and 7(B) show a cross-section A1 - A2 and a cross-section B1 - B2 indicated by a dashed line in Fig. 6. 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. The separator 507 is installed between the positive electrode 503 and the negative electrode 506 provided in the exterior body 509. Also, the interior of the exterior body 509 is filled with the electrolytic solution 508. Fig. 6 shows an external view of the thin battery 500. Figs. 7(A) and 7(B) show a cross-section A1 - A2 and a cross-section B1 - B2 indicated by a dashed line in Fig. 6. 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. The separator 507 is installed between the positive electrode 503 and the negative electrode 506 provided in the exterior body 509. Also, the interior of the exterior body 509 is filled with the electrolytic solution 508. 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. 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. 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. The separator 507 is installed between the positive electrode 503 and the negative electrode 506 provided in the exterior body 509. Also, the interior of the exterior body 509 is filled with the electrolytic solution 508. 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. The separator 507 is installed between the positive electrode 503 and the negative electrode 506 provided in the exterior body 509. Also, the interior of the exterior body 509 is filled with the electrolytic solution 508. 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. The separator 507 is installed between the positive electrode 503 and the negative electrode 506 provided in the exterior body 509. Also, the interior of the exterior body 509 is filled with the electrolytic solution 508.

[0213] 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. 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. 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.

[0214] 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 of using the electrode 100 shown in Embodiment 2 for the positive electrode 503 is shown. 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 of using the electrode 100 shown in Embodiment 2 for the positive electrode 503 is shown. 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 of using the electrode 100 shown in Embodiment 2 for the positive electrode 503 is shown.

[0215] As the solvent of the electrolytic solution 508, an aprotic organic solvent is preferable. For example, ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate, chloro ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate, chloro Ethylene carbonate, vinylene carbonate (VC), γ-butyrolactone, γ-valero lactone, dimethyl carbonate (DMC), diethyl carbonate (DEC), eth yl methyl carbonate (EMC), methyl formate, methyl acetate, methyl butyrate, 1,3-dio xane, 1,4-dioxane, dimethoxyethane (DME), dimethyl sulfoxide, di ethyl ether, methyl diglyme, acetonitrile, benzonitrile, tetrahydrof ran, sulfolane, sultone, etc., one kind, or any combination of two or more of these and ratios can be used.

[0216] In addition, by using a polymer material that is gelled as a solvent for the electrolyte, the safety against leakage and the like is enhanced. Also, the secondary battery can be thinned and lightened. Representative examples of the polymer material to be gelled include silicone gel, acrylic gel, acrylonitrile gel, poly ethylene oxide-based gel, polypropylene oxide-based gel, gel of fluorine-based polymer

[0217] In addition, by using one or more ionic liquids (room temperature molten salts) that are flame retardant and hardly volatile as a solvent for the electrolyte, even if the internal temperature rises due to internal short circuit, overcharge, etc. of the power storage device, rupture or ignition of the power storage device can be prevented. Ionic liquids consist of cations and ani ons and contain organic cations and anions. As the organic cations used in the electrolyte, aliphatic onium cations such as quaternary ammonium cations, tertiary sulfonium cations, and quaternary phosphonium cations, and aromatic cations such as imidazolium cations and pyridinium Anions, monovalent methide-based anions, fluorosulfonate anions, perfluoroalkyl sulfonate anions, tetrafluoroborate, perfluoroalkyl borate, hexa fluorophosphate, or perfluoroalkyl phosphate, etc. may be mentioned.

[0218] In addition, as the electrolyte dissolved in the above solvent, when lithium ions are used as carriers For example, LiPF6, LiClO4, LiAsF6, LiBF4, LiAlCl4, L iSCN, LiBr, LiI, Li2SO4, Li2B 10 Cl 10 、Li2B 12 Cl 12 、LiCF3SO3, LiC4F9SO3, LiC(CF3SO2)3, LiC(C 2F5SO2)3, LiN(CF3SO2)2, LiN(C4F9SO2)(CF3SO 2), LiN(C2F5SO2)2 and other lithium salts can be used alone or in any combination and ratio of two or more of these. It can be used in any combination and ratio.

[0219] In addition, the electrolyte used in the power storage device is preferably a highly purified electrolyte with a low content of particulate dust and elements other than the constituent elements of the electrolyte (hereinafter, simply referred to as "impurities"). Specifically, the weight ratio of impurities to the electrolyte is preferably 1% or less, more preferably 0.1% or less and even more preferably 0.01% or less. It is preferable to set it as such.

[0220] In addition, vinylene carbonate (VC), propane sultone (PS), tert -butylbenzene (TBB), fluoroethylene carbonate (FEC), LiBOB, etc. Any additive may be added. The concentration of the additive is, for example, 0.1weig with respect to the entire solvent It may be 5 weight% or more and 50 weight% or less.

[0221] Alternatively, a gel electrolyte obtained by swelling a polymer with an electrolytic solution may be used. Examples of the gel electrolyte (polymer-gel electrolyte) include those using a host polymer as a carrier and containing the above-described electrolytic solution. Examples of the host polymer will be described below. As the host polymer, for example, polymers having a polyalkylene oxide structure such as polyethylene oxide (PEO), PVdF, and polyacrylonitrile, and copolymers containing them can be used.

[0222] Examples of the host polymer will be described below. As the host polymer, for example, polymers having a polyalkylene oxide structure such as polyethylene oxide (PEO), PVdF, and polyacrylonitrile, and copolymers containing them can be used. For example, PVdF-HFP, which is a copolymer of PVdF and hexafluoropropylene (HFP), can be used. Further, the formed polymer may have a porous shape. For example, PVdF-HFP, which is a copolymer of PVdF and hexafluoropropylene (HFP), can be used. Further, the formed polymer may have a porous shape. For example, PVdF-HFP, which is a copolymer of PVdF and hexafluoropropylene (HFP), can be used. Further, the formed polymer may have a porous shape.

[0223] Alternatively, 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 PEO (polyethylene oxide)-based material can be used. When using a solid electrolyte, it is not necessary to install a separator or a spacer. Further, since the entire battery can be solidified, there is no risk of leakage and the safety is significantly improved. since the entire battery can be solidified, there is no risk of leakage and the safety is significantly improved.

[0224] As the separator 507, for example, those formed of paper, non-woven fabric, glass fiber, ceramics, or nylon (polyamide), vinylon (polyvinyl alcohol-based fiber), polyester, acrylic, polyolefin, synthetic fiber using polyurethane, etc. can be used. can be used.

[0225] The separator 507 is processed into a bag shape and wraps either the positive electrode 503 or the negative electrode 506. It is preferably arranged as follows. For example, as shown in Fig. 8(A), the separator 507 is folded in two so as to sandwich the positive electrode 503, and is sealed by the sealing portion 514 outside the region overlapping with the positive electrode 503, whereby the positive electrode 503 can be surely supported within the separator 507. Then, as shown in Fig. 8(B), the positive electrode 503 and the negative electrode 506 wrapped by the separator 507 are alternately laminated, and these are arranged within the exterior body 509 to form a thin rechargeable battery 500. Here, an example will be described in which particles having the lithium manganese composite oxide shown in Embodiment 1 are used as the positive electrode active material, the electrode shown in Embodiment 1 is used as the positive electrode 503, and an active material having silicon is used as the negative electrode active material. The active 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 rechargeable battery. Here, in the charging and discharging of the rechargeable 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 because it has no 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. In such a case, the negative electrode 506 or the positive electrode 503 used in the rechargeable battery, the counter electrode, and the electrolytic solution

[0226]

[0227]

[0228]

[0229] , a battery provided in advance is fabricated, and after causing an irreversible reaction in advance, the negative electrode 506 or the positive electrode 503 is taken out from the battery to fabricate a storage battery, which is preferable because it can suppress the reduction in the capacity of the storage battery due to the irreversible reaction. 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. Examples of the metal having carrier ions include lithium and the like. Further, as the compound having carrier ions, for example, the materials mentioned as the positive electrode active material and the negative electrode active material in Embodiment 1 can be used. Next, the aging after fabricating the storage battery will be described. It is preferable to perform aging after fabricating the storage battery. An example of the aging conditions will be described below. First, charging is performed at a rate of 0.001C or more and 0.2C or less. The temperature may be, for example, room temperature or higher and 50 °C or lower. At this time, if the electrolytic solution decomposes and gas is generated, if the gas accumulates in the cell, a region where the electrolytic solution cannot contact the electrode surface will be generated. That is, it corresponds to a decrease in the effective reaction area of the electrode and an increase in the effective current density. Further, the particles having the lithium manganese composite oxide according to one aspect of the present invention have a high reaction potential when used as the positive electrode active material. When the positive electrode active material has a high reaction potential, the voltage of the storage battery can be increased, and the energy density of the storage battery can be increased, which is preferable. Here, the electrolytic solution may not have resistance to such a high reaction potential. For example, when the electrolytic solution decomposes and gas is generated, if the gas accumulates in the cell, a region where the electrolytic solution cannot contact the electrode surface will be generated.

[0230] That is, it corresponds to a decrease in the effective reaction area of the electrode and an increase in the effective current density. Further, the particles having the lithium manganese composite oxide according to one aspect of the present invention have a high reaction potential when used as the positive electrode active material. When the positive electrode active material has a high reaction potential, the voltage of the storage battery can be increased, and the energy density of the storage battery can be increased, which is preferable. First, charging is performed at a rate of 0.001C or more and 0.2C or less. The temperature may be, for example, room temperature or higher and 50 °C or lower. At this time, if the electrolytic solution decomposes and gas is generated, if the gas accumulates in the cell, a region where the electrolytic solution cannot contact the electrode surface will be generated. That is, it corresponds to a decrease in the effective reaction area of the electrode and an increase in the effective current density. Further, the particles having the lithium manganese composite oxide according to one aspect of the present invention have a high reaction potential when used as the positive electrode active material. When the positive electrode active material has a high reaction potential, the voltage of the storage battery can be increased, and the energy density of the storage battery can be increased, which is preferable. Here, the electrolytic solution may not have resistance to such a high reaction potential. For example, when the electrolytic solution decomposes and gas is generated, if the gas accumulates in the cell, a region where the electrolytic solution cannot contact the electrode surface will be generated. That is, it corresponds to a decrease in the effective reaction area of the electrode and an increase in the effective current density. Further, the particles having the lithium manganese composite oxide according to one aspect of the present invention have a high reaction potential when used as the positive electrode active material. When the positive electrode active material has a high reaction potential, the voltage of the storage battery can be increased, and the energy density of the storage battery can be increased, which is preferable.

[0231] Here, the electrolytic solution may not have resistance to such a high reaction potential. For example, If the electrolytic solution decomposes on the surface of the positive electrode and gas is generated. In such a case it is preferable to vent the gas.

[0232] Also, when the current density becomes excessively high, a voltage drop occurs according to the resistance of the electrode, and at the same time, lithium insertion into the graphite occurs, and lithium deposition on the graphite surface also occurs. This lithium deposition may cause a decrease in capacity. For example, after lithium is deposited, if a film or the like grows on the surface, the lithium deposited on the surface cannot be redissolved and the lithium that does not contribute to the capacity increases. Also, when the deposited lithium physically falls off and loses electrical connection with the electrode even then, lithium that does not contribute to the capacity is generated. Therefore, it is preferable to vent the gas before the electrode reaches the lithium potential due to the voltage drop.

[0233] Also, aging may be performed while applying pressure. For example, after manufacturing a thin rechargeable battery charging and discharging may be performed while applying pressure using a press.

[0234] The lithium manganese composite oxide according to one embodiment of the present invention has a large discharge capacity and is therefore preferable Also, the lithium manganese composite oxide according to one embodiment of the present invention has a high potential for the battery reaction and has a high energy density, which is preferable.

[0235] On the other hand, when an active material having a high battery reaction potential is used as the positive electrode of a rechargeable battery, the electrolytic solution may be easily decomposed. Here, when the electrolytic solution decomposes, gas may be generated near the surface of the positive electrode

[0236] By performing aging while applying pressure, the generated gas is being pressed ​​​​In some cases, it may be possible to expel the fuel to areas other than the designated area, for example to the periphery of the battery, which is preferable.

[0237] Here, for example, pressing may be performed while heating. Although pressing may be performed, it is more preferable to perform aging while pressing.

[0238] After degassing, the mixture is heated to a temperature higher than room temperature, preferably 30° C. to 60° C. More preferably, the temperature is 35° C. or higher and 50° C. or lower, for example, 1 hour or higher and 100 hours or lower. During the first charge, the electrolyte decomposed on the surface is transferred to the graphite surface. For example, by keeping the temperature higher than room temperature after degassing, In some cases, the formed coating may become dense.

[0239] As shown in FIG. 9A, the positive electrode current collector of the positive electrode 503 is welded by ultrasonic welding or the like. The negative electrode 506 is welded to the positive electrode lead electrode 510 at the welding area 512. It is welded to the negative electrode lead electrode 511. FIG. 9(B) shows an example in which a current collector is welded to a lead electrode. As an example, a positive electrode current collector is welded to a positive electrode lead electrode 510. The battery has a curved portion 513 as shown in FIG. 9B, so that the battery can be easily removed after the storage battery 500 is manufactured. This can reduce stress caused by the application of force from the outside, thereby improving the reliability of the storage battery 500. This can be done.

[0240] In the thin storage battery 500 shown in FIGS. 6 and 7, the positive electrode lead electrode 510 is The positive electrode current collector 501 of the negative electrode 506 is connected to the negative electrode lead electrode 511. 504 to form a positive lead electrode 510 and a negative lead electrode 511. It is exposed on the outside. Also, the role of the terminal for obtaining electrical contact with the outside can be served by both the positive electrode current collector 501 and the negative electrode current collector 504. In that case, without using lead electrodes, a part of the positive electrode current collector 501 and the negative electrode current collector 504 may be arranged so as to be exposed outside from the exterior body 509.

[0241] Also, in FIG. 6, the positive electrode lead electrode 510 and the negative electrode lead electrode 511 are arranged on the same side, but as shown in FIG. 10, the positive electrode lead electrode 510 and the negative electrode lead electrode 511 may be arranged on different sides. As described above, since the lead electrodes of the battery according to one aspect of the present invention can be freely arranged, the degree of design freedom is high. Therefore, the degree of design freedom of a product using the battery according to one aspect of the present invention can be increased. Also, the productivity of a product using the battery according to one aspect of the present invention can be increased.

[0242] In the thin battery 500, on the film made of a material such as polyethylene, polypropylene, polycarbonate, ionomer, polyamide, etc. of the exterior body 509, an aluminum, stainless steel, copper, nickel, etc. metal thin film with excellent flexibility is provided, and further, 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 on the metal thin film. A three-layer film can be used.

[0243] Also, in FIG. 6, as an example, the number of pairs of the facing positive and negative electrodes is set to 5 pairs, but of course, the number of pairs of electrodes is not limited to 5 pairs, and may be more or less. When the number of electrode layers is large, a battery having a larger capacity can be obtained. Also, when the number of electrode layers is small, a thin and flexible battery can be obtained. ​

[0244] In the above configuration, the exterior body 509 of the secondary battery can be deformed within a range having a curvature radius of 30 mm or more, preferably 10 mm or more. The film that is the exterior body of the secondary battery is composed of one or two sheets. In the case of a secondary battery having a laminated structure, the cross-sectional structure of the curved battery is a structure sandwiched between two curves of the film that is the exterior body. The curvature radius of the surface will be described with reference to FIG. 11. In FIG. 11(A), in the plane 1701 obtained by cutting the curved surface 170

[0245] 0, a part of the curve 1702 included in the curved surface 1700 is approximated by an arc of a circle, and the radius of the circle is defined as the curvature radius 1703 and the center of the circle is defined as the curvature center 1704. FIG. 11(B) shows a top view of the curved surface 1700. FIG. 11(C) shows a cross-sectional view obtained by cutting the curved surface 170 0 with the plane 1701. When the curved surface is cut by a plane, the curvature radius of the curve appearing in the cross-section varies depending on the angle of the plane with respect to the curved surface and the cutting position. In this specification and the like, the smallest curvature radius is defined as the curvature radius of the surface. When the secondary battery has two films as the exterior body and sandwiches 1805 such as electrodes and electrolytes and is curved, the curvature radius 1802 of the film 1801 closer to the curvature center 1800 of the secondary battery is smaller than the curvature radius 1804 of the film 1803 farther from the curvature center 1800 ( FIG. 12(A)). When the secondary battery is curved to form an arc-shaped cross-section, compressive stress is applied to the surface of the film closer to the curvature center 1800, and tensile stress is applied to the surface of the film farther from the curvature center 1800 (

[0246] FIG. 12(B)). When a pattern formed by concave or convex portions is formed on the surface of the exterior body, even if such compressive stress or tensile stress is applied, the influence of strain FIG. 12(A)). When the secondary battery is curved to form an arc-shaped cross-section, compressive stress is applied to the surface of the film closer to the curvature center 1800, and tensile stress is applied to the surface of the film farther from the curvature center 1800 ( FIG. 12(B)). When a pattern formed by concave or convex portions is formed on the surface of the exterior body, even if such compressive stress or tensile stress is applied, the influence of strain FIG. 12(A)). When the secondary battery is curved to form an arc-shaped cross-section, compressive stress is applied to the surface of the film closer to the curvature center 1800, and tensile stress is applied to the surface of the film farther from the curvature center 1800 ( FIG. 12(B)). When a pattern formed by concave or convex portions is formed on the surface of the exterior body, even if such compressive stress or tensile stress is applied, the influence of strain is small. is small. can be suppressed within an allowable range. Therefore, the secondary battery can be deformed within a range where the radius of curvature of the outer package on the side closer to the center of curvature is 30 mm or more, preferably 10 mm or more.

[0247] Note that the cross-sectional shape of the secondary battery is not limited to a simple arc shape, and can be a shape having a partial arc, for example, the shape shown in FIG. 12(C), a wavy shape (FIG. 12(D)), an S-shaped shape, etc. When the curved surface of the secondary battery has a shape having a plurality of centers of curvature, among the radii of curvature at each of the plurality of centers of curvature, in the curved surface having the smallest radius of curvature, the radius of curvature of the outer package closer to the center of curvature of the two outer packages is 10 mm or more, preferably 30 mm or more, and the secondary battery can be deformed.

[0248] 〈Coin-shaped storage battery〉 Next, as an example of the power storage device, an example of a coin-shaped storage battery will be described with reference to FIG. 13. FIG. 13(A) is an external view of a coin-shaped (single-layer flat type) storage battery, and FIG. 13(B) is its cross-sectional view.

[0249] The coin-shaped storage battery 300 has a positive electrode can 301 that also serves as a positive electrode terminal and a negative electrode can 302 that also serves as a negative electrode terminal, 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, refer to the description of the positive electrode active material layer 502.

[0250] 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, refer to the description of the negative electrode active material layer 505. ​​​For the separator 310, the description of the separator 507 may be referred to. For the solution, see the description of the electrolyte 508.

[0251] The positive electrode 304 and the negative electrode 307 used in the coin-type storage battery 300 are each an active material. The barrier layer need only be formed on one side.

[0252] The positive electrode can 301 and the negative electrode can 302 are made of nickel or aluminum, which is resistant to corrosion by the electrolyte. Metals such as aluminum and titanium, or their alloys or alloys of these with other metals (e.g. stainless steel In order to prevent corrosion by the electrolyte, nickel or aluminum can be used. The positive electrode can 301 is a positive electrode 304, and the negative electrode can 302 is a negative electrode. 307 and electrically connected to each other.

[0253] The negative electrode 307, the positive electrode 304 and the separator 310 are impregnated with an electrolyte, and the negative electrode 307, the positive electrode 304 and the separator 310 are impregnated with an electrolyte. As shown in Fig. 2B, the positive electrode can 301 is placed downward, and the positive electrode 304, the separator 310, and the negative electrode 307 are placed in the same position. The positive electrode can 301 and the negative electrode can 302 are stacked in this order, and the positive electrode can 301 and the negative electrode can 302 are secured together with a gasket 303. The coin-shaped storage battery 300 is manufactured by crimping the wires through a wire cutout.

[0254] <Cylindrical storage battery> Next, a cylindrical storage battery will be shown as an example of a power storage device. The cylindrical storage battery 600 has a positive electrode on the upper surface as shown in FIG. It has a cap (battery cover) 601 and a battery can (outer can) 602 on the side and bottom. The positive electrode cap and the battery can (outer can) 602 are connected with a gasket (insulating packing) 602. It is insulated by 10.

[0255] FIG. 14(B) is a diagram schematically showing a cross section of a cylindrical storage battery. A hollow cylindrical battery Inside the can 602, a strip-shaped positive electrode 604 and a negative electrode 606 are sandwiched with a separator 605 in between and a wound battery element is provided. Although not shown, the battery element is wound around a center pin The battery can 602 has one end closed and the other end open. The battery can 602 is made of a metal such as nickel, aluminum, titanium, etc. that is corrosion-resistant to the electrolytic solution, or an alloy of these or an alloy of these and other metals (for example, stainless steel, etc.) can be used . Further, in order to prevent corrosion by the electrolytic solution, it is preferable to coat with nickel or aluminum, etc . Inside the battery can 602, the battery element in which the positive electrode, the negative electrode, and the separator are wound is sandwiched between a pair of opposing insulating plates 608 and 609. Also, the inside of the battery can 602 where the battery element is provided is filled with a non-aqueous electrolytic solution (not shown). The non-aqueous electrolytic solution can be the same as that used for a coin-type storage battery

[0256] The positive electrode 604 and the negative electrode 606 may be manufactured in the same manner as the positive electrode and the negative electrode of the above-described thin storage battery . Also, since the positive electrode and the negative electrode used for 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) 60 3 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. The positive electrode terminal 603 and the negative electrode terminal 607 can both 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 a PTC element (Positive Tempe It is electrically connected to the positive electrode cap 601 via the 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. Also, the PTC element 611 is a thermal resistance element whose resistance increases when the temperature rises, and it limits the current flow to prevent abnormal heat generation. For the PTC element, barium titanate ( BaTiO3)-based semiconductor ceramics or the like can be used.

[0257] When winding the electrodes like in a cylindrical storage battery as shown in Fig. 14, a large stress acts on the electrodes during winding. Also, when the wound electrode body is housed in the casing, a stress always acts on the electrodes toward the outside of the winding axis. Even if such a large stress acts on the electrodes, it is possible to prevent the active material from splitting.

[0258] In this embodiment, coin-type, cylindrical, and thin-type storage batteries are shown as the storage battery, but storage batteries of various shapes such as other sealed-type storage 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 storage batteries are shown in Figs. 15 to 19.

[0259] 〈Configuration example of storage battery〉 Figs. 15 and 16 show a configuration example of a thin-type storage battery. The wound body 99 3 shown in Fig. 15(A) has a negative electrode 994, a positive electrode 995, and a separator 996.

[0260] In the wound body 993, the negative electrode 994 and the positive electrode 995 overlap with each other with the separator 996 in between. They are laminated and the laminated sheet is wound. By covering this wound body 993 with a rectangular sealing container, a rectangular secondary battery is manufactured.

[0261] Note that the number of laminations of the laminate 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.

[0262] The storage batteries 990 shown in FIGS. 15(B) and 15(C) are 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 thereby. The wound body 993 has lead electrodes 997 and 998 and is impregnated with an electrolytic solution inside the film 981 and the film 982 having a recess.

[0263] 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 storage battery having flexibility can be manufactured.

[0264] In FIGS. 15(B) and 15(C), an example using two films is shown. However, a space may be formed by bending one film, and the above-described wound body 993 may be housed in the space. ​​​​​​​​​​​​​​​

[0265] Also, by using a resin material or the like for the exterior body of the thin battery or the sealing container, flexibility can be achieved to produce a power storage device. However, when using a resin material for the exterior body or the sealing container, the portion for external connection shall be made of a conductive material.

[0266] For example, FIG. 16 shows an example of another thin battery having flexibility. Since the wound body 9 93 shown in FIG. 16(A) is the same as that shown in FIG. 15(A), detailed description thereof will be omitted. .

[0267] The batteries 990 shown in FIGS. 16(B) and 16(C) house the wound body 993 described above 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 992. The exterior bodies 991 and 992 can be made of, for example, a metal material such as aluminum or a resin material. If a resin material is used as the material of the exterior bodies 991 and 992, the exterior bodies 9 91 and 992 can be deformed when a force is applied from the outside, and a thin battery having flexibility can be produced.

[0268] By using the electrode containing the active material according to one aspect of the present invention in a thin battery having flexibility, even if stress acts on the electrode by repeatedly bending the thin battery, it is possible to prevent the active material from splitting.

[0269] As described above, by using, for the electrode, an active material covered with graphene on at least a part of the cleavage surface, 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.

[0270] 〈Structural example of the power storage system〉 In addition, a structural example of the power storage system will be described with reference to FIGS. 17 to 19. Here, the power storage system refers to, for example, a device equipped with a power storage device.

[0271] FIGS. 17(A) and 17(B) are diagrams showing the external views of the power storage system. The power storage system includes a circuit board 900 and a storage battery 913. A label 91 0 is attached to the storage battery 913. Further, as shown in FIG. 17(B), the power storage system includes a terminal 951 and , a terminal 952, an antenna 914, and an antenna 915.

[0272] The circuit board 900 includes a terminal 911 and a circuit 912. The terminal 911 is connected to the terminal 95 1, the terminal 952, the antenna 914, the antenna 915, and the circuit 912. Note that a plurality of terminals 911 may be provided, and each of the plurality of terminals 911 may be used as a control signal input terminal, a power supply terminal, etc.

[0273] 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 plane antennas, aperture antennas, traveling wave antennas, EH antennas, magnetic field antennas, inductive body antennas, etc. may be used. Alternatively, the antenna 914 or the antenna 91 5 may be a flat conductor. This flat conductor can function as one of the conductors of the capacitor. That is, as one of the two conductors of the capacitor, it can function as one of the two conductors of the capacitor. Antenna 914 or antenna 915 may be activated. As a result, power can be exchanged not only by an electromagnetic field and a magnetic field but also by an electric field.

[0274] The line width of antenna 914 is preferably larger than that of antenna 915. Thus, the amount of power received by antenna 914 can be increased.

[0275] The power storage system has layer 9 16 between antennas 914 and 915 and the storage battery 913. Layer 916 has a function of shielding, for example, the electromagnetic field generated by the storage battery 913. As layer 916, for example, a magnetic material can be used.

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

[0277] For example, as shown in FIGS. 18(A-1) and 18(A-2), antennas may be provided on each of a pair of opposing surfaces of the storage battery 913 shown in FIGS. 17(A) and 17(B). FIG. 18(A-1) is an external view seen from one side direction of the pair of surfaces, and FIG. 1 8(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. 17(A) and 17(B), the description of the power storage system shown in FIGS. 17(A) and 1 7(B) can be appropriately incorporated. As shown in FIG. 18(A-1), antenna 914 is provided with layer 916 interposed therebetween on one of the pair of surfaces of storage battery 913, and as shown in FIG. 18(A-2), antenna 915 is provided with layer 917 interposed therebetween on the other

[0278] of the pair of surfaces of storage battery 913. Layer 917 has a function of shielding, for example, the electromagnetic field generated by the storage battery 913. As shown in FIG. 18(A-2), antenna 915 is provided with layer 917 interposed therebetween on the other of the pair of surfaces of storage battery 913. Layer 917 has a function of shielding, for example, the electromagnetic field generated by the storage battery 913. It has a function capable of shielding the electromagnetic field generated thereby. As the layer 917, for example, a magnetic material can be used. can be used.

[0279] By adopting the above structure, the sizes of both the antenna 914 and the antenna 915 can be increased. can be increased.

[0280] Alternatively, as shown in FIGS. 18(B-1) and 18(B-2), another antenna may be provided on each of a pair of opposing surfaces of the storage battery 913 shown in FIGS. 17(A) and 17(B). FIG. 18(B-1) is an external view seen from one side direction of the pair of surfaces, and FIG. 18(B-2) is an external view seen from the other side direction of the pair of surfaces. For the same parts as those of the power storage system shown in FIGS. 17(A) and 17(B), the description of the power storage system shown in FIGS. 17(A) and 17(B) can be appropriately incorporated. For the same parts as those of the power storage system shown in FIGS. 17(A) and 17(B), the description of the power storage system shown in FIGS. 17(A) and 17(B) can be appropriately incorporated. Alternatively, as shown in FIGS. 18(B-1) and 18(B-2), another antenna may be provided on each of a pair of opposing surfaces of the storage battery 913 shown in FIGS. 17(A) and 17(B). FIG. 18(B-1) is an external view seen from one side direction of the pair of surfaces, and FIG. 18(B-2) is an external view seen from the other side direction of the pair of surfaces. For the same parts as those of the power storage system shown in FIGS. 17(A) and 17(B), the description of the power storage system shown in FIGS. 17(A) and 17(B) can be appropriately incorporated. Alternatively, as shown in FIGS. 18(B-1) and 18(B-2), another antenna may be provided on each of a pair of opposing surfaces of the storage battery 913 shown in FIGS. 17(A) and 17(B). FIG. 18(B-1) is an external view seen from one side direction of the pair of surfaces, and FIG. 18(B-2) is an external view seen from the other side direction of the pair of surfaces. For the same parts as those of the power storage system shown in FIGS. 17(A) and 17(B), the description of the power storage system shown in FIGS. 17(A) and 17(B) can be appropriately incorporated. Alternatively, as shown in FIGS. 18(B-1) and 18(B-2), another antenna may be provided on each of a pair of opposing surfaces of the storage battery 913 shown in FIGS. 17(A) and 17(B). FIG. 18(B-1) is an external view seen from one side direction of the pair of surfaces, and FIG. 18(B-2) is an external view seen from the other side direction of the pair of surfaces. For the same parts as those of the power storage system shown in FIGS. 17(A) and 17(B), the description of the power storage system shown in FIGS. 17(A) and 17(B) can be appropriately incorporated. Alternatively, as shown in FIGS. 18(B-1) and 18(B-2), another antenna may be provided on each of a pair of opposing surfaces of the storage battery 913 shown in FIGS. 17(A) and 17(B). FIG. 18(B-1) is an external view seen from one side direction of the pair of surfaces, and FIG. 18(B-2) is an external view seen from the other side direction of the pair of surfaces. For the same parts as those of the power storage system shown in FIGS. 17(A) and 17(B), the description of the power storage system shown in FIGS. 17(A) and 17(B) can be appropriately incorporated.

[0281] As shown in FIG. 18(B-1), the antennas 914 and 915 are provided with the layer 916 interposed therebetween on one of the pair of surfaces of the storage battery 913, and as shown in FIG. 18(A-2), the antenna 918 is provided with the layer 917 interposed therebetween on the other of the pair of surfaces of the storage battery 913. The antenna 918 has a function capable of, for example, performing data communication with an external device. The antenna 918 may be 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. As shown in FIG. 18(B-1), the antennas 914 and 915 are provided with the layer 916 interposed therebetween on one of the pair of surfaces of the storage battery 913, and as shown in FIG. 18(A-2), the antenna 918 is provided with the layer 917 interposed therebetween on the other of the pair of surfaces of the storage battery 913. The antenna 918 has a function capable of, for example, performing data communication with an external device. The antenna 918 may be 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. As shown in FIG. 18(B-1), the antennas 914 and 915 are provided with the layer 916 interposed therebetween on one of the pair of surfaces of the storage battery 913, and as shown in FIG. 18(A-2), the antenna 918 is provided with the layer 917 interposed therebetween on the other of the pair of surfaces of the storage battery 913. The antenna 918 has a function capable of, for example, performing data communication with an external device. The antenna 918 may be 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. As shown in FIG. 18(B-1), the antennas 914 and 915 are provided with the layer 916 interposed therebetween on one of the pair of surfaces of the storage battery 913, and as shown in FIG. 18(A-2), the antenna 918 is provided with the layer 917 interposed therebetween on the other of the pair of surfaces of the storage battery 913. The antenna 918 has a function capable of, for example, performing data communication with an external device. The antenna 918 may be 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. As shown in FIG. 18(B-1), the antennas 914 and 915 are provided with the layer 916 interposed therebetween on one of the pair of surfaces of the storage battery 913, and as shown in FIG. 18(A-2), the antenna 918 is provided with the layer 917 interposed therebetween on the other of the pair of surfaces of the storage battery 913. The antenna 918 has a function capable of, for example, performing data communication with an external device. The antenna 918 may be 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. As shown in FIG. 18(B-1), the antennas 914 and 915 are provided with the layer 916 interposed therebetween on one of the pair of surfaces of the storage battery 913, and as shown in FIG. 18(A-2), the antenna 918 is provided with the layer 917 interposed therebetween on the other of the pair of surfaces of the storage battery 913. The antenna 918 has a function capable of, for example, performing data communication with an external device. The antenna 918 may be 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. As shown in FIG. 18(B-1), the antennas 914 and 915 are provided with the layer 916 interposed therebetween on one of the pair of surfaces of the storage battery 913, and as shown in FIG. 18(A-2), the antenna 918 is provided with the layer 917 interposed therebetween on the other of the pair of surfaces of the storage battery 913. The antenna 918 has a function capable of, for example, performing data communication with an external device. The antenna 918 may be 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. As shown in FIG. 18(B-1), the antennas 914 and 915 are provided with the layer 916 interposed therebetween on one of the pair of surfaces of the storage battery 913, and as shown in FIG. 18(A-2), the antenna 918 is provided with the layer 917 interposed therebetween on the other of the pair of surfaces of the storage battery 913. The antenna 918 has a function capable of, for example, performing data communication with an external device. The antenna 918 may be 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.

[0282] Alternatively, as shown in FIG. 19(A), another antenna may be provided on each of a pair of opposing surfaces of the storage battery 913 shown in FIGS. 17(A) and 17(B). A display device 920 may be provided at 3. The display device 920 is electrically connected to the terminal 911 via the terminal 919. A label 910 may not be provided at the portion where the display device 920 is provided. Regarding the same parts as the power storage system shown in FIGS. 17(A) and 17(B), the description of the power storage system shown in FIGS. 17(A) and 17(B) can be appropriately incorporated. Regarding the same parts as the power storage system shown in FIGS. 17(A) and 17(B), the description of the power storage system shown in FIGS. 17(A) and 17(B) can be appropriately incorporated.

[0283] The display device 920 may display, for example, an image indicating whether it is charging or not, an image indicating the power storage amount, etc. As the display device 920, for example, electronic paper, a liquid crystal display device, an electroluminescence (EL) display device, etc. can be used. For example, by using electronic paper, the power consumption of the display device 920 can be reduced. For example, by using electronic paper, the power consumption of the display device 920 can be reduced.

[0284] Alternatively, as shown in FIG. 19(B), a sensor 921 may be provided in the battery 913 shown in FIGS. 17(A) and 17(B). The sensor 921 is electrically connected to the terminal 911 via the terminal 922. Regarding the same parts as the power storage system shown in FIGS. 17(A) and 17(B), the description of the power storage system shown in FIGS. 17(A) and 17(B) can be appropriately incorporated. Regarding the same parts as the power storage system shown in FIGS. 17(A) and 17(B), the description of the power storage system shown in FIGS. 17(A) and 17(B) can be appropriately incorporated. Regarding the same parts as the power storage system shown in FIGS. 17(A) and 17(B), the description of the power storage system shown in FIGS. 17(A) and 17(B) can be appropriately incorporated.

[0285] As the sensor 921, for example, those 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 line, flow rate, humidity, gradient, vibration, odor or infrared rays can be used. As the sensor 921, for example, those 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 line, flow rate, humidity, gradient, vibration, odor or infrared rays can be used. As the sensor 921, for example, those 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 line, 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. 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. 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.

[0286] In the battery and power storage system shown in this embodiment, the electrode according to one aspect of the present invention is used. Therefore, the capacity of the battery and the power storage system can be increased. In addition, the energy density can be increased. In addition, the reliability can be improved. In addition, the life can be extended long.

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

[0288] (Embodiment 3) In this embodiment, an example of mounting a flexible battery on an electronic device will be described.

[0289] An example of mounting the flexible battery shown in Embodiment 2 on an electronic device is shown in FIG. 20. The electronic devices to which a power storage device having a flexible shape is applied include, for example, a television set (also referred to as a television 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 mobile phone or a mobile phone device), a portable game machine, a portable information terminal, an audio reproduction device, a pachinko machine, and large game machines such as these.

[0290] In addition, it is also possible to incorporate a power storage device 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.

[0291] FIG. 20(A) shows an example of a mobile phone. The mobile phone 7400 includes, in addition to a display unit 7402 incorporated in a housing 740 1, operation buttons 7403, an external connection port 7404, a speaker 7405, a microphone 7406, and the like. Note that the mobile phone 7400 is a storage It has an electric device 7407.

[0292] FIG. 20(B) shows a state in which the mobile phone 7400 is bent. When the mobile phone 74 00 is deformed by an external force and bent as a whole, the power storage device 7407 provided inside it is also bent. Also, at that time, the state of the bent power storage device 7407 is shown in FIG. 20( C). The power storage device 7407 is a thin battery. The power storage device 7407 is fixed in a bent state. Incidentally, the power storage device 7407 has a lead electrode 7408 electrically connected to a current collector 7409.

[0293] FIG. 20(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. 20(E) shows the state of the bent power storage device 7104. 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. Incidentally, the value obtained by representing the degree of bending at an arbitrary point on the curve by the radius of the corresponding circle is the radius of curvature, and the reciprocal of the radius of curvature is called the curvature. Specifically, within the range where the radius of curvature is 40 mm or more and 150 mm or less, part or all of the main surface of the housing or the power storage device 7104 changes. 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.

[0294] FIG. 20(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 7 205, input / output terminals 7206, etc.

[0295] The mobile information terminal 7200 can execute various applications such as mobile phones, e-mails, text viewing and creation, music playback, Internet communication, and computer games. possible.

[0296] The display unit 7202 is provided with a curved display surface and can perform display along the curved display surface. In addition, the display unit 7202 is equipped with a touch sensor and can be operated by touching the screen with a finger or a stylus. For example, by touching the icon 7207 displayed on the display unit 7202, an application can be launched.

[0297] In addition to time setting, the operation button 7205 can have various functions such as power on / off, wireless communication on / off, execution and cancellation of the silent mode, and execution and cancellation of the power saving mode. For example, the function of the operation button 7205 can also be freely set by the operating system incorporated in the mobile information terminal 7200.

[0298] In addition, the mobile information terminal 7200 can execute communication-standardized short-range wireless communication. For example, by communicating with a wireless headset, hands-free calling is also possible.

[0299] In addition, the mobile information terminal 7200 is equipped with an input / output terminal 7206 and can directly exchange data with other information terminals via a connector. In addition, charging can also be performed via the input / output terminal 7206. Note that the charging operation may be performed by wireless power supply without passing through the input / output terminal 7206.

[0300] ​​​​​​​​ The display unit 7202 of the mobile information terminal 7200 is provided with a power storage device including the electrode member of one aspect of the present invention. For example, the power storage device 7104 shown in FIG. 20(E) can be incorporated inside the housing 7201 in a curved state or in a state where it can be curved inside the band 7203.

[0301] FIG. 20(G) shows an example of a bracelet-type display device. The display device 7300 has a display unit 7304 and includes a power storage device of one aspect of the present invention. In addition, the display device 7300 can be provided with a touch sensor on the display unit 7304 and can also function as a mobile information terminal.

[0302] The display surface of the display unit 7304 is curved, and display can be performed along the curved display surface. In addition, the display device 7300 can change the display status by means of communication-standardized short-range wireless communication or the like.

[0303] 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 passing through the input / output terminals.

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

[0305] (Embodiment 4) In this embodiment, an example of an electronic device capable of mounting a power storage device is shown.

[0306] FIGS. 21(A) and 21(B) show an example of a foldable tablet-type terminal. The tablet terminal 9600 shown in FIGS. 21(A) and 21(B) includes a housing 9630a, a housing 9630b, a movable part 9640 that connects the housing 9630a and the housing 9630b, a display unit 9 631a and a display unit 9631 having a display unit 9631b, a display mode switching switch 96 26, a power switch 9627, a power saving mode switching switch 9625, a fastener 9629 , and an operation switch 9628. FIG. 21(A) shows the state in which the tablet terminal 9600 is opened , and FIG. 21(B) shows the state in which the tablet terminal 9600 is closed.

[0307] Further, the tablet terminal 9600 has a power storage body 9635 inside the housing 9630a and the housing 9630b. The power storage body 9635 is provided through the movable part 9640 and extends across the housing 9630a and the housing 9630b.

[0308] A part of the display unit 9631a can be a touch panel area 9632a, and data can be input by touching the displayed operation keys 9638. Note that, in the display unit 96 31a, as an example, a configuration in which half of the area has only a display function and the other half of the area has a touch panel function is shown, but the present invention is not limited to this configuration. The entire area of the display unit 96 31a may also have a touch panel function. For example, the entire surface of the display unit 9 631a can be made to display keyboard buttons to serve as a touch panel, and the display unit 9631b can be used as a display screen. Further, in the display unit 9631b as well, similar to the display unit 9631a, a part of the display unit 9631b can be a touch panel area 9632b. Also, the keyboard of the touch panel buttons can be displayed and used as a touch panel, and the display unit 9631b can be used as a display screen.

[0309] Similarly, in the display unit 9631b, a part of the display unit 9631b can be made into a touch panel area 9632b. Also, the keyboard of the touch panel can be Touch the position where the display switching button 9639 is displayed with a finger, a stylus, etc. The keyboard buttons can be displayed on the display unit 9631b.

[0310] Also, touch input can be performed simultaneously on the touch panel area 9632a and the touch panel area 9632b.

[0311] Also, the display mode switching switch 9626 can select switching of 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 into the tablet terminal 9600 during use. The tablet terminal may incorporate other detection devices such as sensors for detecting inclination, such as a gyro and an acceleration sensor, in addition to the optical sensor.

[0312] Also, in FIG. 21(A), an example where the display areas of the display unit 9631b and the display unit 9631a are the same is shown, but it is not particularly limited, and one size and the other size may be different, and the display quality may also be different. For example, one may be a display panel that can perform higher-definition display than the other.

[0313] FIG. 21(B) shows a closed state, and the tablet terminal includes a housing 9630, a solar cell 9 633, and a charge / discharge control circuit 9634 including 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.

[0314] Since the tablet terminal 9600 can be folded in two, when not in use, the housing 9630a ​​​​​​The call housing 9630b can be folded so as to be overlapped. By folding, the display units 9631a and 9631b can be protected, thus enhancing the durability of the tablet terminal 9600. Further, the power storage body 9635 using the power storage body of one aspect of the present invention has flexibility and is less likely to have a reduced charge-discharge capacity even when repeatedly bent and stretched. Therefore, a tablet terminal with excellent reliability can be provided.

[0315] In addition, the tablet terminals shown in FIGS. 21(A) and 21(B) also have functions of displaying various information (such as still images, moving images, text images, etc.), a function of displaying a calendar, date, or time on the display unit, a touch input function of touch-inputting or editing the information displayed on the display unit, a function of controlling processing by various software (programs), and the like can be provided.

[0316] Power can be supplied to the touch panel, display unit, video signal processing unit, etc. by the solar cell 9633 mounted on the surface of the tablet 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 as the power storage body 9635, using a lithium-ion battery has advantages such as enabling miniaturization.

[0317] Further, the configuration and operation of the charge-discharge control circuit 9634 shown in FIG. 21(B) will be described with reference to the block diagram in FIG. 21 (C). FIG. 21(C) shows the solar cell 9633, the power storage body 96 35, the DCDC converter 9636, the converter 9637, the switches SW1 to SW3, and the display unit 9631. The power storage body 9635, the DCDC converter 9636, the co​​ The inverter 9637 and switches SW1 to SW3 correspond to the charging / discharging control circuit 9 shown in FIG. 21(B) at the corresponding location in 634.

[0318] 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 is stepped up or down by the DCDC converter 9636 so as to be a voltage for charging the power storage body 9635. And 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 963 7 steps up or down to the voltage required for the display unit 9631. Also, when the display on the display unit 963 1 is not performed, SW1 may be turned off and SW2 may be turned on to charge the power storage body 9635.

[0319] Note that the solar cell 9633 is shown as an example of a power generation means, but is not particularly limited, and the power storage body 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 wirelessly (non - contact) transmits and receives power for charging, or a configuration that combines other charging means may be used.

[0320] FIG. 22 shows an example of another electronic device. In FIG. 22, 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 80 00 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 is supplied with power from a commercial power source ​​​​ It can also receive power and use the power stored in the power storage device 8004. Therefore, even when power supply from the commercial power supply cannot be received due to a power outage or the like, by using the power storage device 8004 according to one aspect of the present invention as an uninterruptible power supply, the display device 8000 can be used.

[0321] The display unit 8002 includes a light-emitting device having a light-emitting element such as a liquid crystal display device or an organic EL element in each pixel, an electrophoretic display device, a DMD (Digital Micromirror Device), a PDP (Plasma Display Panel), an FED (Field Emission Display), etc., and a semiconductor display device can be used.

[0322] In addition to those for receiving TV broadcasts, the display device includes all display devices for information display such as those for personal computers and for advertising displays.

[0323] In FIG. 22, the installed lighting device 8100 is an example of an electronic device using the power storage device 8 103 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. 22, the case where the power storage device 8103 is provided inside the ceiling 8104 where the housing 8 101 and the light source 8102 are installed is shown as an example, but the power storage device 8103 may be provided inside the housing 8101. The lighting device 8100 can receive power supply from the commercial power supply and can also use the power stored in the power storage device 8103. Therefore, even when power supply from the commercial power supply 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 display device 8000 can be used. ​​​​By doing so, the lighting device 8100 can be used.

[0324] In addition, in FIG. 22, an example of a fixed-type lighting device 8100 provided on the ceiling 8104 is illustrated. However, the power storage device according to one aspect of the present invention can be used not only for the ceiling 8104 but also for fixed-type lighting devices provided on, for example, side walls 8105, floors 8106, windows 8107, etc., and can also be used for table-top lighting devices and the like.

[0325] In addition, 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.

[0326] In FIG. 22, an air conditioner having an indoor unit 8200 and an outdoor unit 8204 is an example of an electronic device using the 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, and the like. FIG. 22 illustrates a 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 can use the power stored in the power storage device 8203. In particular, when the power storage device 8 203 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. ​

[0327] Note that in FIG. 22, a separate type air conditioner composed of an indoor unit and an outdoor unit is exemplified. However, the power storage device according to one aspect of the present invention can also be used for an integrated type air conditioner having the functions of the indoor unit and the outdoor unit in one housing. In FIG. 22, an electric refrigerator 8300 is an example of an electronic device using the power storage device 8304 according to one aspect of the present invention. Specifically, the electric refrigerator 8300 has a housing 8301,

[0328] a door 8302 for the refrigerator compartment, a door 8303 for the freezer compartment, a power storage device 8304, etc. In FIG. 22, the power storage device 8304 is provided inside the housing 8301. The electric refrigerator 8300 can receive power supply from a commercial power source, and can also 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 the power storage device according to one aspect of the present invention as an auxiliary power supply to supplement the power that cannot be covered by the commercial power source, it is possible to prevent the breaker of the commercial power source from tripping when the electronic device is in use.

[0329] Note that 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 the power storage device according to one aspect of the present invention as an auxiliary power supply to supplement the power that cannot be covered by the commercial power source, it is possible to prevent the breaker of the commercial power source from tripping when the electronic device is in use. In addition, during the time when the electronic device is not in use, particularly during the time 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, the storage

[0330] Also, during the time when the electronic device is not in use, particularly during the time 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, the storage In addition, during the time when the electronic device is not in use, particularly during the time 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, the storage By storing power in the electrical device, it is possible to suppress an increase in the power usage rate outside the above time period. For example, in the case of the electric refrigerator 8300, during the night when the temperature is low and the doors 83 02 for the refrigerator compartment and 8303 for the freezer compartment are not opened or closed, power is stored in the power storage device 8304. Then, during the day when the temperature rises and the doors 8302 for the refrigerator compartment and 8303 for the freezer compartment are opened and closed, by using the power storage device 8304 as an auxiliary power source, the power usage rate during the day can be kept low.

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

[0332] (Embodiment 5) In this embodiment, an example of mounting a power storage device on a vehicle is shown.

[0333] 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.

[0334] In FIG. 23, a vehicle using one aspect of the present invention is illustrated. The automobile 8400 shown in FIG. 23(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 can not only drive the electric motor 8406, but also supply power to lighting devices such as headlights 8401 and a room light (not shown).

[0335] In addition, the power storage device can supply power to display devices such as a speedometer and a tachometer of the vehicle 8400. In addition, the power storage device can supply power to semiconductor devices such as a navigation system of the vehicle 8400.

[0336] The vehicle 8500 shown in Fig. 23(B) can be charged by receiving power supply from an external charging facility by a plug-in method, a non-contact power supply method, or the like to the power storage device of the vehicle 8500. Fig. 23(B) shows a state in which charging is being performed from a ground-mounted charging device 8021 to a power storage device 8024 mounted on the vehicle 8500 via a cable 8022. At the time of charging, the charging method, the connector standard, etc. may be appropriately performed in a predetermined method such as CHAdeMO (registered trademark) or Combo. The charging device 8021 may be a charging station provided in a commercial facility or may be a household power source. For example, by plug-in technology, the power storage device 8024 mounted on the 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.

[0337] Although not shown, a power receiving device can be mounted on the vehicle, and power can be supplied and charged non-contact from a power transmission device on the ground. In the case of this non-contact power supply method, by incorporating a power transmission 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. In addition, power transmission and reception may be performed between vehicles using this non-contact power supply method. Furthermore, a solar cell may be provided on the exterior of the vehicle to charge the power storage device when the vehicle is stopped or running. For power supply, electromagnetic induction or magnetic field resonance can be used.

[0338] 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 power storage device itself can be made smaller and lighter. If the power storage device itself can be made smaller and lighter, it contributes to the weight reduction of the vehicle, and the cruising range can be improved. In addition, the power 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.

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

[0340] (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. 24 to 30. In this embodiment, the battery control unit of a power storage device having battery cells connected in series will be particularly described. When repeatedly charging and discharging a plurality of battery cells connected in series, variations in charge and discharge characteristics occur between the battery cells, and the capacities (output voltages) of the respective battery cells become different.

[0341] When repeatedly charging and discharging a plurality of battery cells connected in series, variations in charge and discharge characteristics occur between the battery cells, and the capacities (output voltages) of the respective battery cells become different. Among 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 respective battery cells, the overall capacity during discharge becomes smaller. ​​​​​​​However, if charging is performed based on a battery cell with a small capacity, there is a risk of undercharging. Also, if charging is performed based on a battery cell with a large capacity, there is a risk of overcharging.

[0342] Therefore, the battery control unit of a power storage device having battery cells connected in series has a function of equalizing the capacity variations between the battery cells that cause undercharging or overcharging. Circuit configurations for equalizing the capacity variations between battery cells include a resistance method, a capacitor method, or 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 a 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 leaking from the battery can be reduced, and the decrease in capacity over time can be suppressed. As the oxide semiconductor used in the channel formation region, In-M-Zn oxide (M is Ga, Sn

[0343] , Y, Zr, La, Ce, or Nd) is used. In the target used for forming the oxide semiconductor film, the atomic ratio of the metal elements is set to In:M:Zn = x1:y1:z1 and x1 / y1 is 1 / 3 or more and 6 or less, further 1 or more and 6 or less, and z1 / y1 is preferably 1 / 3 or more and 6 or less, further 1 or more and 6 or less. By setting z1 / y1 to 1

[0344] or more and 6 or less, a CAAC-OS film is likely to be formed as the oxide semiconductor film. For forming the oxide semiconductor film, the target used has an atomic ratio of metal elements of In:M:Zn = x1:y1:z1. where x1 / y1 is 1 / 3 or more and 6 or less, and preferably 1 or more and 6 or less, and z1 / y1 is 、 1 / 3 or more and 6 or less, and preferably 1 or more and 6 or less. By setting z1 / y1 to 1 or more and 6 or less, a CAAC-OS film is likely to be formed as the oxide semiconductor film. .

[0345] Here, the CAAC-OS film will be described.

[0346] The CAAC-OS film is one of the oxide semiconductor films having a plurality of c-axis oriented crystal parts. .

[0347] By using a transmission electron microscope (TEM: Transmission Electron Micr oscope), a plurality of crystal parts can be confirmed by observing a composite analysis image of a bright-field image and a diffraction pattern of the CAAC-OS film (also referred to as a high-resolution TEM image). On the other hand, clear boundaries between crystal parts, that is, grain boundaries (also referred to as grain boundaries), cannot be confirmed by a high-resolution TEM image. Therefore, it can be said that the CAAC-OS film is less likely to cause a decrease in electron mobility due to grain boundaries. When observing a high-resolution TEM image of the cross section of the CAAC-OS film from a direction substantially parallel to the sample surface,

[0348] it can be confirmed that metal atoms are arranged in layers in the crystal part. Each layer of metal atoms has a shape that reflects the unevenness of the surface (also referred to as the formed surface) or the upper surface of the CAAC-OS film, and is arranged parallel to the formed surface or the upper surface of the CAAC-OS film. On the other hand, when observing a high-resolution TEM image of the plane of the CAAC-OS film from a direction substantially perpendicular to the sample surface,

[0349] it can be confirmed that metal atoms are arranged in a triangular shape or a hexagonal shape in the crystal part. However, no regularity is seen in the arrangement of metal atoms between different crystal parts. When performing structural analysis on the CAAC-OS film using an X-ray diffraction (XRD: X-Ray Diffraction) apparatus, for example, a CAAC-OS having a crystal of InGaZnO4

[0350] When performing structural analysis on the CAAC-OS film using an X-ray diffraction (XRD: X-Ray Diffraction) apparatus, for example, a CAAC-OS having a crystal of InGaZnO4 In the analysis of the film by the out-of-plane method, a peak may appear near a diffraction angle (2θ) of 31°. Since this peak is attributed to the (009) plane of the InGaZnO4 crystal, it can be confirmed that the crystal of the CAAC-OS film has c-axis orientation, and the c-axis is oriented in a direction substantially perpendicular to the formed surface or the upper surface.

[0351] In addition, in the analysis of the CAAC-OS film having the InGaZnO4 crystal by the out-of-plane method, in addition to the peak near 2θ of 31°, a peak may also appear near 2θ of 36°. The peak near 2θ of 36° indicates that a part of the CAAC-OS film contains crystals that do not have c-axis orientation. It is preferable that the CAAC-OS film shows a peak near 2θ of 31° and does not show a peak near 2θ of 36°.

[0352] 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 such as silicon, which have a stronger binding force with oxygen than the metal elements constituting the oxide semiconductor film, disrupt the atomic arrangement of the oxide semiconductor film by taking oxygen from the oxide semiconductor film, leading to a decrease in crystallinity. In addition, 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 disrupt the atomic arrangement of the oxide semiconductor film and become a factor in reducing crystallinity. Note that impurities contained in the oxide semiconductor film may be carrier traps or carrier generation sources.

[0353] In addition, the CAAC-OS film is an oxide semiconductor film with a low density of defect levels. For example, oxidation ​​​​​​​​​​Oxygen deficiencies in the oxide semiconductor film can act as carrier traps or generate carriers by capturing hydrogen.

[0354] 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 can have a low carrier density because there are few carrier generation sources. Therefore, a transistor using such an oxide semiconductor film is less likely to have an electrical characteristic where the threshold voltage becomes negative (also called normally on). Also, an oxide semiconductor film that is high-purity intrinsic or substantially high-purity intrinsic has few carrier traps. Therefore, a transistor using such an oxide semiconductor film has small fluctuations in electrical characteristics and becomes a highly reliable transistor. Note that the charge trapped in the carrier traps 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. Also, a transistor using a CAAC-OS film has small fluctuations in electrical characteristics due to irradiation with visible light or ultraviolet light.

[0355] In addition, a transistor using a CAAC-OS film has small fluctuations in electrical characteristics due to irradiation with visible light or ultraviolet light.

[0356] 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 in the circuit configuration of a battery control unit applied to such battery cells in a power storage device, the above ​​​​​​​​It is suitable to be composed of the above-described OS transistor.

[0357] FIG. 24 shows an example of a block diagram of a power storage device. The power storage device BT00 shown in FIG. 24 includes a terminal pair BT01, a terminal pair BT02, a switching control circuit BT03, a switching circuit BT 04, a switching circuit BT05, a voltage conversion control circuit BT06, a voltage conversion circuit BT07, and a battery unit BT08 including a plurality of battery cells BT09 connected in series.

[0358] Also, in the power storage device BT00 of FIG. 24, the terminal pair BT01, the terminal pair BT02, and the switching control circuit BT03, the switching circuit BT04, the switching circuit BT05, and the voltage conversion control circuit BT06 and the voltage conversion circuit BT07 can be referred to as a battery control unit.

[0359] 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 a battery cell to be discharged (discharging battery cell group) and a battery cell to be charged (charging battery cell group) based on the voltages measured for each battery cell BT09.

[0360] Furthermore, the switching control circuit BT03 outputs a control signal S1 and a control signal S2 based on the determined discharging battery cell group and charging 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 discharging 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 charging battery cell group. ​​​​It is a signal for controlling the switching circuit BT05 so as to connect with the

[0361] Also, based on the configurations of the switching circuit BT04, the switching circuit BT05, and the transformer circuit BT07, between the terminal pair BT01 and the discharge battery cell group, or between the terminal pair BT02 and the charge battery cell group, control signals S1 and S2 are generated so that terminals of the same polarity are connected to each other.

[0362] The details of the operation of the switching control circuit BT03 will be described.

[0363] First, the switching control circuit BT03 measures the voltage of each of the plurality of battery cells BT09. Then, the switching control circuit BT03 determines, for example, a battery cell BT09 with a voltage equal to or higher than a predetermined threshold as a high-voltage battery cell (high-voltage cell), and a battery cell BT09 with a voltage lower than the predetermined threshold as a low-voltage battery cell (low-voltage cell).

[0364] Note that various methods can be used to determine the high-voltage cells and low-voltage cells. For example, the switching control circuit BT03 can determine whether each battery cell BT09 is a high-voltage cell or a low-voltage cell based on the voltage of the battery cell BT09 with the highest or lowest voltage among the plurality of battery cells BT09. In this case, the switching control circuit BT0 3 can determine whether each battery cell BT09 is a high-voltage cell or a low-voltage cell by determining whether the voltage of each battery cell BT09 is equal to or higher than a predetermined ratio with respect to the reference voltage. 3. Then, based on this determination result, the switching control circuit BT03 determines the discharge battery cell group and the charge battery cell group.

[0365] ​​​​​Among a plurality of battery cells BT09, high-voltage cells and low-voltage cells may be mixed in various states. For example, the switching control circuit BT03 determines a portion where the high-voltage cells are most continuously connected in series as the discharge battery cell group among the mixture of high-voltage cells and low-voltage cells. Further, the switching control circuit BT03 determines a portion where the low-voltage cells are most continuously connected in series as the charge battery cell group. Also, the switching control circuit BT03 may preferentially select a battery cell BT09 that is close to overcharge or over-discharge as the discharge battery cell group or the charge battery cell group. Here, an operation example of the switching control circuit BT03 in the present embodiment will be described with reference to FIG. 25. FIG. 25 is a diagram for explaining the operation example of the switching control circuit BT03. For convenience of explanation, in FIG. 25, a case where four battery cells BT09 are connected in series will be described as an example.

[0366] First, in the example of FIG. 25(A), assuming that the voltages of battery cells a to d are voltage Va to voltage Vd, a case where Va = Vb = Vc > Vd is shown. 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 discharge battery cell group. Also, the switching control circuit BT03 determines the low-voltage cell d as the charge battery cell group.

[0367] Next, in the example of FIG. 25(B), a case where Vc > Va = Vb >> Vd is shown. That is, two consecutive low-voltage cells a, b, one high-voltage cell c, and one over-discharged In this case, the switching control circuit BT03 determines the high-voltage cell c as the discharge battery cell group. Also, the switching control circuit BT03 determines the two low-voltage cells a and b and the over-discharged cell as the charge battery cell group.

[0368] cell are shown. That is, two consecutive low-voltage cells a, b, one high-voltage cell c, and one over-discharged cell are shown. The adjacent low-voltage cell d is connected in series. In this case, the switching control circuit BT03 determines the high-voltage cell c as the discharge battery cell group. Also, the switching control circuit BT03 determines the low-voltage cell d as the charge battery cell group preferentially because the low-voltage cell d is near over-discharge, rather than the two consecutive low-voltage cells a and b.

[0369] Finally, the example of FIG. 25(C) shows the 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.

[0370] Based on the results determined as in the examples of FIGS. 25(A) to (C) above, the switching control circuit BT03 outputs the control signal S1 in which the information indicating the discharge battery cell group that is the connection destination of the switching circuit BT04 is set, and the control signal S2 in which the information indicating the charge battery cell group that is the connection destination of the switching circuit BT05 is set, to the switching circuit BT04 and the switching circuit BT05, respectively.

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

[0372] 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.

[0373] The terminal pair BT01 is composed of the paired terminals A1 and A2. The switching circuit BT0 4 connects either one of the terminals A1 and A2 to the positive terminal of the battery cell BT09 located at the most upstream (high potential side) in the discharge battery cell group, and the other to the negative terminal of the battery cell BT09 located at the 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.

[0374] The switching circuit BT05 sets the connection destination of the terminal pair BT02 to the charge battery cell group determined by the switching control circuit BT03 according to the control signal S2 output from the switching control circuit BT03.

[0375] The terminal pair BT02 is composed of the paired terminals B1 and B2. The switching circuit BT0 5 connects either one of the terminals B1 and B2 to the positive terminal of the battery cell BT09 located at the most upstream (high potential side) in the charge battery cell group, and the other to the negative terminal of the battery cell BT09 located at the most downstream (low potential side) in the charge 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 charge battery cell group using the information set in the control signal S2.

[0376] Circuit diagrams showing configuration examples of the switching circuit BT04 and the switching circuit BT05 are shown in FIGS. 26 and 27.

[0377] In FIG. 26, the switching circuit BT04 includes a plurality of transistors BT10 and a bus BT11 and BT12. The bus BT11 is connected to the terminal A1. Also, the bus BT 12 is connected to the terminal A2. One of the sources or drains of the plurality of transistors BT10 is connected to the buses BT11 and BT12 alternately, one by one. Also the other of the sources or drains of the plurality of transistors BT10 is connected between every two adjacent battery cells BT09.

[0378] Note that, among the plurality of transistors BT10, the other of the source or drain of the transistor BT10 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 transistors BT10, the other of the source or drain of the transistor BT10 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 The switching circuit BT04 connects the discharge battery cell group and the terminal pair BT01 by making 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 conductive according to the control signal S1 applied to the gates of the plurality of transistors BT10. Thereby, the positive terminal of the battery cell BT09 located at the 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 terminal of the battery cell BT09 located at the 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 terminal.

[0379] The switching circuit BT04 connects the discharge battery cell group and the terminal pair BT01 by making 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 conductive according to the control signal S1 applied to the gates of the plurality of transistors BT10. Accordingly, 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 are made conductive respectively to connect the discharge battery cell group and the terminal pair BT01. Thereby, the positive terminal of the battery cell BT09 located at the 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 terminal of the battery cell BT09 located at the 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 terminal. Accordingly, the positive terminal of the battery cell BT09 located at the 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 terminal of the battery cell BT09 located at the 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 terminal. Accordingly, the positive terminal of the battery cell BT09 located at the 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 terminal of the battery cell BT09 located at the 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 terminal.

[0380] It is preferable to use an OS transistor for the transistor BT10. Since the OS transistor has a small off-current, it is possible to reduce the amount of charge leaking from a battery cell that does not belong 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 if the output voltage of the discharge battery cell group is

[0381] large, it is possible to insulate the battery cell BT09 to which the transistor BT10 in the non-conducting state is connected from the terminal pair BT01. Also, in FIG. 26, 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 BT16 are arranged between the plurality of transistors BT13 and the current control switch BT14. One of the source or drain of the plurality of transistors BT13 is connected to the buses BT15 and BT16 alternately, one by

[0382] one. Also, the other of the source or drain of the plurality of transistors BT13 is connected between two adjacent battery cells BT09. Note that the other of the source or drain of the transistor BT13 located furthest upstream among the plurality of transistors BT13 is connected to the positive terminal of the battery cell BT09 located furthest upstream in the

[0383] battery unit BT08. Also, the other of the source or drain of the transistor This is preferable. Since the OS transistor has a small off-current, it does not belong to the rechargeable battery cell group and can reduce the amount of charge leaking from the battery cell and suppress the capacity degradation 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 to which the non-conducting transistor B T13 is connected and the terminal pair BT02 can be insulated. .

[0384] The current control switch BT14 has a switch pair BT17 and a switch pair BT18. One end of the switch pair BT17 is connected to the terminal B1. Also, the other end of the switch pair BT17 branches into 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 into two switches, one switch is connected to the bus BT15, and the other switch is connected to the bus BT16 .

[0385] The switches of the switch pair BT17 and the switch pair BT18 preferably use OS transistors, similar to the transistor BT1 0 and the transistor BT13.

[0386] 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 and the terminal pair BT02.

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

[0388] The switching circuit BT05 turns on the transistor BT13 connected to the positive terminal of the battery cell BT09 located most upstream in the rechargeable battery cell group according to the control signal S2 applied to the gates of the plurality of transistors BT13 . Also, the switching circuit BT05 turns on the transistor BT1 3 connected to the negative terminal of the battery cell BT09 located most downstream in the rechargeable battery cell group according to the control signal S2 applied to the gates of the plurality of transistors BT13 .

[0389] 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 allow a current to flow 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 . 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 B T18 according to the polarity of the voltage applied to the terminal pair BT02 .

[0390] 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 BT0 9 at the most downstream of the battery unit BT08 is a rechargeable battery cell group, the switch pair BT17 is controlled by the control signal S2 to be connected to the positive 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 bus BT of the switch pair BT17 The switch connected to 15 is turned off. On the other hand, the switch pair BT18 is controlled by the control signal S 2 to be connected to the negative 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 pair the switch connected to the bus BT16 of BT18 is turned off. In this way, between the terminal pair BT02 and the rechargeable battery cell group, terminals with the same polarity are connected. And the direction of the current flowing from the terminal pair BT02 is controlled so as to be in the direction of charging the rechargeable battery cell group is controlled.

[0391] Also, the current control switch BT14 may be included in the switching circuit BT04 instead of the switching circuit BT05. In this case, by controlling the polarity of the voltage applied to the terminal pair BT01 according to the current control switch BT14 and the control signal S1, the polarity of the voltage applied to the terminal pair BT02 is controlled. And the current control switch BT14 controls the direction of the current flowing from the terminal pair BT0 2 to the rechargeable battery cell group.

[0392] FIG. 27 is a circuit diagram showing a configuration example of the switching circuit BT04 and the switching circuit BT05 different from FIG. 26.

[0393] In FIG. 27, the switching circuit BT04 has a plurality of transistor pairs BT21, and buses BT2 4 and bus BT25. The bus BT24 is connected to the terminal A1. Also, the ba s BT25 is connected to the terminal A2. One ends of the plurality of transistor pairs BT21 are each branched by a transistor BT22 and a transistor BT23. One of the source or drain of the transistor BT22 is connected to the bus BT24. Also, the tra​​ 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 respectively connected between two adjacent battery cells BT09 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

[0394] The switching circuit BT04 switches the conduction / non - conduction states of the transistors BT22 and BT23 according to the control signal S1, thereby switching the connection destination of the transistor pair BT21 to either terminal A1 or terminal A2. Specifically, if the transistor BT22 is in the conduction state, the transistor BT23 is in the non - conduction state, and its connection destination is terminal A1. On the other hand, if the transistor BT23 is in the conduction state, the transistor BT22 is in the non - conduction state, and its connection destination is terminal A2. Which of the transistors BT22 and BT23 is in the conduction state is determined by the control signal S1 terminal A1. On the other hand, if the transistor BT23 is in the conduction state, the transistor BT22 is in the non - conduction state, and its connection destination is terminal A2. Which of the transistors BT22 and BT23 is in the conduction state is determined by the control signal S1 terminal A1. On the other hand, if the transistor BT23 is in the conduction state, the transistor BT22 is in the non - conduction state, and its connection destination is terminal A2. Which of the transistors BT22 and BT23 is in the conduction state is determined by the control signal S1 22 is in the non - conduction state, and its connection destination is terminal A2. Whether the transistor BT22 or the transistor BT23 is in the conduction state is determined by the control signal S1

[0395] To connect the terminal pair BT01 and the discharge battery cell group, two transistor pairs BT21 are used. Specifically, based on the control signal S1, the connection destinations of the two transistor pairs BT21 are respectively determined, whereby the discharge battery cell group and the terminal pair BT01 are connected The connection destination of each of the two transistor pairs BT21 is such that one becomes terminal A1 and the other becomes terminal ​​​​It is controlled by the control signal S1 so as to be sub A2.

[0396] The switching circuit BT05 has a plurality of transistor pairs BT31, a bus BT34, and a bus BT35. The bus BT34 is connected to the terminal B1. Also, the bus BT35 is connected to the terminal B2. One end of each of the plurality of transistor pairs BT31 branches into a transistor BT32 and a transistor BT33. One end that branches into the transistor BT32 is connected to the bus BT34. Also, one end that branches by the transistor BT33 is connected to the bus BT35. Also, the other ends of the plurality of transistor pairs BT31 are connected between two adjacent battery cells BT09, respectively. Note that, among the plurality of transistor pairs BT31, the other end of the transistor pair BT31 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 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 in the battery unit BT08.

[0397] The switching circuit BT05 switches the connection destination of the transistor pair BT31 to either the terminal B1 or the terminal B2 by switching the conduction / non-conduction states of the transistor BT32 and the transistor BT33 according to the control signal S2. 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. The transistor BT32 and the transistor BT ​ Which of the diodes BT33 becomes conductive is determined by the control signal S2.

[0398] 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 ends of the two transistor pairs BT31 are respectively determined, whereby the rechargeable battery cell group and the terminal pair BT02 are connected. For each of the two transistor pairs BT31, one connection end becomes terminal B1 and the other becomes the terminal B2, and is controlled by the control signal S2.

[0399] Also, the connection ends 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 terminal B1 is the positive electrode and terminal B2 is the negative electrode is applied to the terminal pair BT02, the upstream transistor pair BT31 is controlled by the control signal S2 such that the transistor BT32 becomes conductive and the transistor BT33 becomes non-conductive. On the other hand, the downstream transistor pair BT31 is controlled by the control signal S2 such that the transistor BT33 becomes conductive and the transistor BT32 becomes non-conductive. 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 such that the transistor BT33 becomes conductive and the transistor BT32 becomes non-conductive. On the other hand, the downstream transistor pair BT31 is controlled by the control signal S2 such that the transistor BT32 becomes conductive and the transistor BT33 becomes non-conductive. In this way, between the terminal pair BT02 and the rechargeable battery cell group, the same connection is achieved. Terminals having the same polarity are connected. And the direction of the current flowing from the terminal pair BT02 is controlled so as to be the direction of charging the rechargeable battery cell group.

[0400] The voltage conversion control circuit BT06 controls the operation of the voltage conversion circuit BT07. The voltage conversion control circuit BT06 generates a voltage conversion signal S3 for controlling the operation of the voltage conversion 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 conversion circuit BT07.

[0401] 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 excessively large charging voltage from being applied to the rechargeable battery cell group. Therefore, the voltage conversion control circuit BT06 outputs a voltage conversion signal S3 for controlling the voltage conversion circuit BT07 so as to step down the discharge voltage (Vdis) within a range where the rechargeable battery cell group can be charged.

[0402] When the number of battery cells BT09 included in the discharge battery cell group is equal to or less than the number of battery cells BT09 included in the rechargeable battery cell group, it is necessary to ensure the charging voltage required for charging the rechargeable battery cell group. Therefore, the voltage conversion control circuit BT06 outputs a voltage conversion signal S3 for controlling the voltage conversion circuit BT07 so as to step up the discharge voltage (Vdis) within a range where an excessive charging voltage is not applied to the rechargeable battery cell group.

[0403] The voltage value for the excessive charging voltage can be determined in view of the product specifications of the battery cell BT09 used in the battery unit BT08. Also, the voltage conversion circuit BT07 steps up and steps down ​​​​​​​​​​​​The applied voltage is applied to the terminal pair BT02 as the charging voltage (Vcha).

[0404] Here, an operation example of the voltage conversion control circuit BT06 in the present embodiment will be described with reference to FIGS. 28(A) to (C ). FIGS. 28(A) to (C) are conceptual diagrams for explaining an operation example of the voltage conversion control circuit BT06 corresponding to the discharging battery cell group and the charging battery cell group described with reference to FIGS. 25(A) to (C . Note that FIGS. 28(A) to (C) show 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 BT 05, the voltage conversion control circuit BT06, and the voltage conversion circuit BT07, as described above . In the example shown in FIG. 28(A), as described with reference to FIG. 25(A), three consecutive high-voltage cells a to c and one low-voltage cell d are connected in series . In this case, as described with reference to FIG. 25(A), the switching control circuit BT03 determines the high-voltage cells a to c as the discharging battery cell group and the low-voltage cell d as the charging battery cell group

[0405] . Then, the voltage conversion control circuit BT06 calculates the conversion ratio N from the discharging voltage (Vdis) to the charging voltage (Vcha) based on the ratio of the number of battery cells BT09 included in the charging battery cell group to the number of battery cells BT09 included in the discharging battery cell group, with the number of battery cells BT09 included in the discharging battery cell group as a reference . When the number of battery cells BT09 included in the discharging battery cell group is larger than the number of battery cells BT09 included in the charging battery cell group, if the discharging voltage is directly applied to the terminal pair BT02 without voltage conversion, the battery cells BT09 included in the charging battery cell group will be damaged through the terminal pair BT02 . Therefore, the voltage conversion control circuit BT06 is used to calculate the conversion ratio N to ensure the safety of the charging battery cell group . And, the voltage conversion control circuit BT06 determines the high-voltage cells a to c as the discharging battery cell group and the low-voltage cell d as the charging battery cell group . Then, based on the ratio of the number of battery cells BT09 included in the charging battery cell group to the number of battery cells BT09 included in the discharging battery cell group, with the number of battery cells BT09 included in the discharging battery cell group as a reference , the voltage conversion control circuit BT06 calculates the conversion ratio N from the discharging voltage (Vdis) to the charging voltage (Vcha ).

[0406] . When the number of battery cells BT09 included in the discharging battery cell group is larger than the number of battery cells BT09 included in the charging battery cell group , if the discharging voltage is directly applied to the terminal pair BT02 without voltage conversion , the battery cells BT09 included in the charging battery cell group will be damaged through the terminal pair BT02 There is a possibility that an excessive voltage may be applied. Therefore, in the case as shown in Fig. 28(A) it is necessary to step down the charging voltage (Vcha) applied to the terminal pair BT02 below the discharging voltage Furthermore, in order to charge the rechargeable battery cell group, the charging voltage needs to be larger than the total voltage of the battery cells BT09 included in the rechargeable battery cell group Therefore, the transformer control circuit BT06 sets the conversion ratio N to be larger than the ratio of the number of battery cells BT09 included in the rechargeable battery cell group based on the number of battery cells BT09 included in the discharging battery cell group

[0407] The transformer control circuit BT06 sets the conversion ratio N to be about 1 to 10% larger than the ratio of the number of battery cells BT09 included in the rechargeable battery cell group based on the number of battery cells BT09 included in the discharging battery cell group At this time, the charging voltage becomes larger than the voltage of the rechargeable battery cell group, but actually the charging voltage becomes equal to the voltage of the rechargeable battery cell group. However, in order for the transformer control circuit BT06 to make the voltage of the rechargeable battery cell group equal to the charging voltage according to the conversion ratio N a current for charging the rechargeable battery cell group will flow. This current becomes the value set in the transformer control circuit BT06

[0408] In the example shown in Fig. 28(A), since the number of battery cells BT09 included in the discharging 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 conversion ratio N. Then, the transformer control circuit BT06 steps down the discharging voltage according to the conversion ratio N and outputs a transformer signal S 3 for converting it into the charging voltage to the transformer circuit BT07. Then, the transformer circuit BT07 responds to the transformer signal S3 ​​​​​Apply the transformed charging voltage to terminal pair BT02. Then, the battery cell BT09 included in the rechargeable battery cell group is charged by the charging voltage applied to terminal pair BT02.

[0409] Also, in the examples shown in FIGS. 28(B) and 28(C), similar to FIG. 28(A), the conversion ratio N is calculated. In the examples shown in FIGS. 28(B) and 28(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 conversion ratio N is 1 or more. Therefore, in this case, the voltage conversion control circuit BT06 outputs a voltage conversion signal S3 for boosting the discharge voltage and converting it into a charging voltage.

[0410] Based on the voltage conversion signal S3, the voltage conversion circuit BT07 converts the discharge voltage applied to terminal pair BT01 into a charging voltage. Then, the voltage conversion circuit BT07 applies the converted charging voltage to terminal pair BT 02. Here, the voltage conversion circuit BT07 electrically insulates between terminal pair BT01 and terminal pair BT02. Thereby, the voltage conversion circuit BT07 prevents a short circuit due to the difference in the absolute voltage of the negative terminal of the battery cell BT09 located most downstream in the discharge battery cell group and the absolute voltage of the negative terminal of the battery cell BT09 located most downstream in the rechargeable battery cell group. Further, as described above, the voltage conversion circuit BT07 converts the discharge voltage, which is the total voltage of the discharge battery cell group, into a charging voltage based on the voltage conversion signal S3.

[0411] Also, the voltage conversion circuit BT07 can use, for example, an isolated DC (Direct Current)-D C converter or the like. In this case, the voltage conversion control circuit BT06 uses, as the voltage conversion signal S3, a signal for controlling the on / off ratio (duty ratio) of the isolated DC -DC converter. ​​​​​​​​​By outputting, the charging voltage converted by the transformer circuit BT07 is controlled.

[0412] Note that for isolated DC-DC converters, there are flyback, forward, RCC (Ringing Choke Converter), push-pull, half bridge, and full bridge methods, etc. However, an appropriate method is selected according to the magnitude of the target output voltage.

[0413] The configuration of the transformer circuit BT07 using an isolated DC-DC converter is shown in FIG. 29. 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 realized using a MOSFET (Metal-Oxide-Semicondu ctor Field-Effect Transistor) or a bipolar transistor, etc. Also, the switch section BT52 periodically switches the on state and off state of the isolated DC-DC converter BT51 based on the transformer control signal S3 that is output from the transformer control circuit BT06 and controls the on / off ratio. Note that the switch section BT52 can have various configurations depending on the method of the isolated DC-DC converter used. The transformer section BT53 converts the discharge voltage applied from the terminal pair BT01 into a charging voltage. Specifically, the transformer section BT53 operates in conjunction with the on / off state of the switch section BT52 and converts the discharge voltage into a charging voltage according to its on / off ratio. This charging voltage becomes larger as the time in the on state is longer during the switching period of the switch section BT 52. On the other hand, the charging voltage is converted into a charging voltage according to its on / off ratio. This charging voltage becomes larger as the time in the on state is longer during the switching period of the switch section BT52. On the other hand, the charging section BT53 operates in conjunction with the on / off state of the switch section BT52 and converts the discharge voltage into a charging voltage according to its on / off ratio. This charging voltage becomes larger as the time in the on state is longer during the switching period of the switch section BT 52. That is, the longer the time in the on state, the larger the charging voltage. On the other hand, the charging The power supply voltage becomes smaller as the time during which it is in the on state is shorter in the switching period of the switch unit BT52. In the case of 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.

[0414] The flow of processing of the power storage device BT00 in this embodiment will be described with reference to FIG. 30. FIG. 3 0 is a flowchart showing the flow of processing of the power storage device BT00.

[0415] First, the power storage device BT00 acquires the voltages measured for each of the plurality of battery cells BT09 ( step S101). 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 S102). This start condition can be, for example, whether or not the difference between the maximum value and the minimum value of the voltages measured for each of the plurality of battery cells BT09 is equal to or greater than a predetermined threshold value. If this start condition is not satisfied (step S 102: 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 S102: YES), the power storage device BT00 performs a process of equalizing the voltages of the respective battery cells BT09. In this process, 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 S103). Then the power storage device BT00 determines a discharge battery cell group and a charge battery cell group based on the determination result ( step S104). Further, the power storage device BT00 sets a control signal S1 for setting the determined discharge battery cell group as the connection destination of the terminal pair BT01, and the determined charge battery cell group as the terminal pair BT02. Generate a control signal S2 to be set as the connection destination of the sub-pair BT02 (step S105). 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 to the discharge battery cell group, and the switching circuit BT05 connects the terminal pair BT0 2 to the discharge battery cell group (step S106). Also, the power storage device BT00 generates a voltage conversion 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 rechargeable battery cell group (step S107). Then the power storage device BT00 converts the discharge voltage applied to the terminal pair BT01 into a charging voltage based on the voltage conversion signal S3 and applies it to the terminal pair BT02 (step S108). As a result, the charge of the discharge battery cell group is transferred to the rechargeable battery cell group.

[0416] Also, in the flowchart of FIG. 30, although a plurality of steps are described in order, the execution order of each step is not limited to the described order.

[0417] As described above, according to the present embodiment, when moving charge from the discharge battery cell group to the rechargeable battery cell group it is not necessary to have a configuration such as a capacitor method in which the charge from the discharge battery cell group is temporarily stored and then released to the rechargeable battery cell group. As a result, the charge transfer efficiency per unit time can be improved. Also, by the switching circuit BT04 and the switching circuit BT05 the battery cells connected to the voltage conversion circuit in the discharge battery cell group and the rechargeable battery cell group can be switched individually.

[0418] Furthermore, 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 recharge battery cell group, the discharge voltage applied to the terminal pair BT01 is converted into a recharge voltage and applied to the terminal pair BT02. As a result, regardless of how the battery cells BT09 on the discharge side and the recharge side are selected, charge transfer can be achieved without problems. and applied. Regardless of how the battery cells BT09 on the discharge side and the recharge side are selected, charge transfer can be achieved without problems.

[0419] Furthermore, by using OS transistors for the transistors BT10 and BT13, the amount of charge leaking from the battery cells BT09 that do not belong to the recharge battery cell group and the discharge battery cell group can be reduced. As a result, a decrease in the capacity of the battery cells BT09 that do not contribute to charging and discharging can be suppressed. In addition, the OS transistor has less variation in characteristics with respect to heat than an Si transistor. As a result, even when the temperature of the battery cells BT09 rises, normal operations such as switching between the conducting state and the non-conducting state according to the control signals S1 and S2 can be performed. from the battery cells BT09 that do not belong to the recharge battery cell group and the discharge battery cell group can be reduced. As a result, a decrease in the capacity of the battery cells BT09 that do not contribute to charging and discharging can be suppressed. In addition, the OS transistor has less variation in characteristics with respect to heat than an Si transistor. As a result, even when the temperature of the battery cells BT09 rises, normal operations such as switching between the conducting state and the non-conducting state according to the control signals S1 and S2 can be performed.

Example

[0420] In this example, "particles having a lithium manganese composite oxide" according to one aspect of the present invention were produced and their characteristics were evaluated. The production procedure will be described based on the flowchart of FIG. 1.

[0421] <Synthesis> First, particles having a lithium manganese composite oxide were produced.

[0422] (Step S11) First, as starting materials, Li2CO3, MnCO3, and NiO were used, and the ratio (molar ratio) of the starting materials was Li2CO3:MnCO3:NiO = 0.84:0.8062:0 ​​It was weighed so as to be 0.318.

[0423] (Step S12) Next, after adding ethanol to the starting materials, they were mixed using a bead mill. The mixing process was carried out by rotating the processing chamber of the bead mill at a peripheral speed of 10 m / s for a mixing time of 30 minutes, to obtain a mixed raw material.

[0424] (Step S13) Next, the mixed raw material was heat-treated. The heat treatment was carried out in an air atmosphere at a heating temperature of 7 5 °C to evaporate the ethanol contained in the mixed raw material, and a mixed raw material was obtained.

[0425] (Step S14) Next, the mixed raw material was placed in a crucible and fired. The firing process was carried out in a dry air atmosphere with a flow rate of 10 L / min at a firing temperature of 1000 °C for a firing time of 10 hours, to synthesize a lithium manganese composite oxide.

[0426] (Step S15) Next, a crushing process was carried out to break the sintering of the lithium manganese composite oxide in which the primary particles were sintered. The crushing process was carried out by adding ethanol to the sintered lithium manganese composite oxide and then rotating the processing chamber of the bead mill at a peripheral speed of 12 m / s for 4 hours to obtain a powdered lithium manganese composite oxide.

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

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

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

[0430] (Step S18) Next, the graphene oxide coated on the surface of the lithium manganese composite oxide was reduced. Ascorbic acid was used as the reducing agent, and a mixed solution of ethanol and water was used as the solvent. In the mixed solution, the concentration of ethanol was 80% by volume. The lithium With respect to the weight of the ummanganese composite oxide, 16.87 wt% of ascorbic acid and 3.9 wt% of lithium hydroxide were added to prepare a reducing solution. The obtained powder was put into the reducing solution and treated at 60 °C for 3 hours for reduction.

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

[0432] Next, the powder obtained by filtration was ground in a mortar. Then, it was dried at 170 °C under reduced pressure for 10 hours.

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

[0434] <Fabrication of Electrode> Next, an electrode was fabricated using the obtained Sample C. Sample C was used as the active material, acetylene black (AB) was used as the conductive assistant, and PVdF was used as the binder.

[0435] First, PVdF and AB were kneaded with NMP (N-methyl-2-pyrrolidone), a polar solvent. The rotation speed of kneading was 2000 rpm, and the kneading time was 5 minutes. Further, Sample C was added as the active material and kneaded. The rotation speed of kneading was 2000 rpm, and the kneading time was 5 minutes for 1 time, and this was repeated 5 times. Further, NMP was added and kneaded. The rotation speed of kneading was 2000 rpm, and the kneading time was 10 minutes for 1 time, and this was repeated 2 times. Through the above steps, a slurry-like electrode binder composition was obtained. The formulation of the electrode binder composition was Sample C:AB:PVdF = 90:5:5 by weight ratio.

[0436] Next, the electrode binder composition was applied onto an aluminum foil which is a current collector. Note that an undercoat was applied to the surface of the aluminum foil in advance. Thereafter, it was dried at 80 °C for 30 minutes in a ventilation drying oven. Next, the electrode was pressed using a roll press machine. The pressing pressure was adjusted so that the film thickness was reduced by 20% with respect to the film thickness after electrode coating. Also, the pressing temperature was set to 120 °C. Thereafter, heat treatment was further performed. As the heat treatment conditions, a treatment was carried out at 270 °C for 10 hours in a reduced pressure atmosphere (1 kPa). Through the above steps, electrode X having "particles having a lithium manganese composite oxide" which is one aspect of the present invention was obtained.

[0437] Next, a half cell was fabricated using the obtained electrode X. A coin cell was used for the cell. Also, lithium was used for the counter electrode of the half cell. Further, as the electrolytic solution, a mixed solution in which LiPF6 was used as an electrolyte and ethylene carbonate (EC) and diethyl carbonate (DEC), which are aprotic organic solvents, were mixed at a volume ratio of 1:1 was used. Also, polypropylene (PP) was used as the separator. Next, the fabricated half cell was aged at 25 °C. Specifically, as the first charge and discharge, constant current charging was performed at 0.1 C (current density 30 mA / g) to 150 mAh / g, and then constant current discharging was performed at 0.1 C with a lower limit of 2 V. As the second time, constant current charging was performed at 0.1 C to 180 mAh / g, and then constant current discharging was performed at 0.1 C with a lower limit of 2 V. As the third time,

[0438]

[0439] <Half cell characteristics>

[0440] As a target, after performing constant current charging at 0.1C and 210 mAh / g, constant current discharging was performed at 0.1C with a lower limit of 2V. After that, constant current charging at 0.1C and 240 mAh / g was performed for the fourth time, and then constant current discharging was performed at 0.1C with a lower limit of 2V. For the fifth time, after performing constant current charging at 0.1C and 270 mAh / g, constant current discharging was performed at 0.1C with a lower limit of 2V.

[0441] After performing the above aging, the charge-discharge characteristics were measured at 25°C. Charging was performed at a constant current of 0.1C and an upper limit voltage of 4.8V, and discharging was performed at a constant current of 0.1C and a lower limit voltage of 2V. The obtained charge-discharge curve is shown in FIG. 31. By using the particles having a lithium manganese composite oxide according to one aspect of the present invention, a high discharge capacity exceeding 300 mAh / g could be obtained.

Example

[0442] In this example, "particles having a lithium manganese composite oxide", which is one aspect of the present invention, was evaluated by scanning transmission electron microscopy (STEM), energy dispersive X-ray spectroscopy (EDX), and selected area electron diffraction.

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

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

[0445] For electrode H-3, after performing steps S11 to S19 shown in FIG. 1,​​​​​​​ Using the obtained sample (hereinafter referred to as sample H-2), electrode H-3 was fabricated. For the fabrication conditions of the electrode, refer to electrode X shown in Example 1.

[0446] For sample H-1 and electrode H-3, after performing thinning processing using a FIB (Focused Ion Beam System: focused ion beam processing and observation apparatus), observation was carried out using scanning transmission electron microscopy (STEM: Scanning Transmission Elect ron Microscopy). The TEM observation image is shown in Fig. 32. Fig. 32(A) shows the observation result of sample H-1, and (B) shows the observation result of electrode H-3. In both cases, a cross-section of particle 141 having a lithium manganese composite oxide, which is one aspect of the present invention, was observed.

[0447] Next, EDX evaluation was performed on the locations numbered 1 to 5 shown in Figs. 32(A) and (B). The evaluation results for sample H-1 are shown in Table 1, and the evaluation results for electrode H-3 are shown in Table 2, respectively. Also, Table 1 and Table 2 show the distance from the particle surface at each measurement location. Also, Figs. 47 to 51 show the spectra at each measurement point. For sample H-1, the spectrum of measurement point 1 is shown in Fig. 47(A ), that of measurement point 2 is shown in (B), that of measurement point 3 is shown in Fig. 48(A), that of measurement point 4 is shown in (B), and that of measurement point 5 is shown in Fig. 49(A). For electrode H-3, the spectrum of measurement point 1 is shown in Fig. 49(B), that of measurement point 2 is shown in Fig. 50(A), that of measurement point 3 is shown in (B), that of measurement point 4 is shown in Fig. 51(A), and that of measurement point 5 is shown in (B).

[0448] [Table 1]

[0449] ​

Table 2

[0450] Here, in Table 1 and Table 2, the values were normalized so that the sum of the atomic number ratios of manganese, nickel, and oxygen was approximately 100%. was approximately 100%.

[0451] Next, the atomic number ratios of manganese, nickel, and oxygen obtained from EDX were denoted as b, c , and d, respectively, and the value of d÷(b + c) (let it be A) was calculated for each evaluation point. The horizontal axis was the distance from the particle surface, and the vertical axis was the value of A. The graphs plotted for sample H-1 and electrode H-3 are shown in Fig. 33. was the value of A. The graphs plotted for sample H-1 and electrode H-3 are shown in Fig. 33.

[0452] First, the region less than 10 nm from the surface will be described. For sample H-1, the value of A was 1.6 at the measurement point 1.2 nm from the surface, and for electrode H-3, the value of A was 1.9 at the measurement point 2.2 nm from the surface.

[0453] Next, the region 20 nm or more from the surface will be described. For sample H-1, the value of A was 2.4 at the measurement point 26 n m from the surface, and the value of A was greater than 2.4 at the measurement points where the distance from the surface was greater than that. Also, for electrode H-3, the value of A was 2.9 at the measurement point 22 nm from the surface, and the value of A was also greater than 2. 9 at the measurement points where the distance from the surface was greater than that.

[0454] From the above, it can be seen that the ratio A of the number of oxygen atoms to the sum of the number of manganese and nickel atoms is different between the region near the surface and the region closer to the inside of the particle than that region. The particles having a lithium manganese composite oxide according to one aspect of the present invention have different values of A, at least two regions where the value of A is different. It has two regions, and among the two regions, in the region closer to the surface, the value of A may be smaller. There are cases.

[0455] Also, the value of A in the region near the surface, for example, the region within less than 10 nm from the surface, is smaller than the value of A in the region closer to the inside of the particle than this region, for example, the region within 20 nm or more from the surface. Smaller.

[0456] Next, the results of observing the high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM :High-Angle Annular Dark Field Scanning Transmission Electron Microscopy) image of electrode H-3 are shown in Fig. 34. Fig. 34(A) shows the observation results of the region 142 surrounded by the solid line in Fig. 32(B), and Fig. 34 (B) shows the observation results of the region 143 surrounded by the solid line in Fig. 32(B). Here, for the observation of the HAADF-STEM image, a TEM image using a spherical aberration corrector function was observed. In addition, the composite analysis image of the bright-field image and the diffraction pattern by TEM observation is called a high-resolution TEM image. And the high-resolution TEM image using the spherical aberration correction function is particularly called a Cs-corrected high-resolution TEM image. For the acquisition of the Cs-corrected high-resolution TEM image, a JEOL ARM200F atomic-resolution analytical electron microscope manufactured by JEOL Ltd. was used. The acceleration voltage was 200 kV. Here, in Fig. 34(A), for the side farther from the surface of the particle, layers V1 and V2 where bright spots are formed, and layer T1 which is located between layer V1 and V2 and where darker spots are formed compared to layers V1 and V2 are shown. The distance between layer V1 and T1 and the distance between layer T1 and V2 are approximately equal. Here, for example, manganese Compared with manganese and nickel, lithium has a smaller atomic number and appears darker in HAADF-STEM observations. Therefore, for example, layer T1 in the layered rock salt structure may mainly be a layer formed by lithium among the (0 0 1) planes. In the (0 0 1) plane, for example, layer T1 may mainly be a layer formed by lithium in the layered rock salt structure. In the (0 0 1) plane, for example, layer T1 may mainly be a layer formed by lithium in the layered rock salt structure.

[0457] Next, layers U1 to U3, which are located in a region closer to the surface of the particles than layers V1, V2, and T1, are shown. Here, each of layers U1 to U3 is a layer formed by bright spots with approximately the same brightness. Here, the distance between layers U1 and U3 is approximately equal to the distance between layers V1 and V2. Also, in layer U2 sandwiched between layers U1 and U3, the brightness of the bright spots is brighter compared to layer T1. Next, layers U1 to U3, which are located in a region closer to the surface of the particles than layers V1, V2, and T1, are shown. Here, each of layers U1 to U3 is a layer formed by bright spots with approximately the same brightness. Here, the distance between layers U1 and U3 is approximately equal to the distance between layers V1 and V2. Also, in layer U2 sandwiched between layers U1 and U3, the brightness of the bright spots is brighter compared to layer T1. Next, layers U1 to U3, which are located in a region closer to the surface of the particles than layers V1, V2, and T1, are shown. Here, each of layers U1 to U3 is a layer formed by bright spots with approximately the same brightness. Here, the distance between layers U1 and U3 is approximately equal to the distance between layers V1 and V2. Also, in layer U2 sandwiched between layers U1 and U3, the brightness of the bright spots is brighter compared to layer T1. Next, layers U1 to U3, which are located in a region closer to the surface of the particles than layers V1, V2, and T1, are shown. Here, each of layers U1 to U3 is a layer formed by bright spots with approximately the same brightness. Here, the distance between layers U1 and U3 is approximately equal to the distance between layers V1 and V2. Also, in layer U2 sandwiched between layers U1 and U3, the brightness of the bright spots is brighter compared to layer T1. Next, layers U1 to U3, which are located in a region closer to the surface of the particles than layers V1, V2, and T1, are shown. Here, each of layers U1 to U3 is a layer formed by bright spots with approximately the same brightness. Here, the distance between layers U1 and U3 is approximately equal to the distance between layers V1 and V2. Also, in layer U2 sandwiched between layers U1 and U3, the brightness of the bright spots is brighter compared to layer T1. Therefore, for example, the abundance ratio of manganese and nickel may be higher in layer U2 compared to layer T1.

[0458] Next, microelectron diffraction was evaluated at measurement points 1 (*1) and 2 (*2) in the TEM photograph shown in Fig. 39. Measurement point 2 shown in Fig. 39 is closer to the surface of the particle and is in a region within 10 nm from the surface of the particle. Measurement point 1 is in a region closer to the inside of the particle compared to measurement point 2. The microelectron diffraction results for each measurement point are shown in Fig. 35. Fig. 35(A) shows the microelectron diffraction result of measurement point 1 shown in Fig. 39, and Fig. 35(B) shows that of measurement point 2. Next, microelectron diffraction was evaluated at measurement points 1 (*1) and 2 (*2) in the TEM photograph shown in Fig. 39. Measurement point 2 shown in Fig. 39 is closer to the surface of the particle and is in a region within 10 nm from the surface of the particle. Measurement point 1 is in a region closer to the inside of the particle compared to measurement point 2. The microelectron diffraction results for each measurement point are shown in Fig. 35. Fig. 35(A) shows the microelectron diffraction result of measurement point 1 shown in Fig. 39, and Fig. 35(B) shows that of measurement point 2. Next, microelectron diffraction was evaluated at measurement points 1 (*1) and 2 (*2) in the TEM photograph shown in Fig. 39. Measurement point 2 shown in Fig. 39 is closer to the surface of the particle and is in a region within 10 nm from the surface of the particle. Measurement point 1 is in a region closer to the inside of the particle compared to measurement point 2. The microelectron diffraction results for each measurement point are shown in Fig. 35. Fig. 35(A) shows the microelectron diffraction result of measurement point 1 shown in Fig. 39, and Fig. 35(B) shows that of measurement point 2. Next, microelectron diffraction was evaluated at measurement points 1 (*1) and 2 (*2) in the TEM photograph shown in Fig. 39. Measurement point 2 shown in Fig. 39 is closer to the surface of the particle and is in a region within 10 nm from the surface of the particle. Measurement point 1 is in a region closer to the inside of the particle compared to measurement point 2. The microelectron diffraction results for each measurement point are shown in Fig. 35. Fig. 35(A) shows the microelectron diffraction result of measurement point 1 shown in Fig. 39, and Fig. 35(B) shows that of measurement point 2. Next, microelectron diffraction was evaluated at measurement points 1 (*1) and 2 (*2) in the TEM photograph shown in Fig. 39. Measurement point 2 shown in Fig. 39 is closer to the surface of the particle and is in a region within 10 nm from the surface of the particle. Measurement point 1 is in a region closer to the inside of the particle compared to measurement point 2. The microelectron diffraction results for each measurement point are shown in Fig. 35. Fig. 35(A) shows the microelectron diffraction result of measurement point 1 shown in Fig. 39, and Fig. 35(B) shows that of measurement point 2.

[0459] Also, the measured values of the positional relationships (distance, angle) of the spots in the obtained diffraction pattern showed a good correspondence with the crystal structure of Li2MnO3 described in JCPDS Card No. 84-1634. More specifically, the diffraction pattern of measurement point 1 (Fig. 35(A)) was the same as the diffraction pattern with an incident direction of [-1 -1 0] in the above crystal structure, and that of measurement point 2 (Fig. 35( Also, the measured values of the positional relationships (distance, angle) of the spots in the obtained diffraction pattern showed a good correspondence with the crystal structure of Li2MnO3 described in JCPDS Card No. 84-1634. More specifically, the diffraction pattern of measurement point 1 (Fig. 35(A)) was the same as the diffraction pattern with an incident direction of [-1 -1 0] in the above crystal structure, and that of measurement point 2 (Fig. 35( Also, the measured values of the positional relationships (distance, angle) of the spots in the obtained diffraction pattern showed a good correspondence with the crystal structure of Li2MnO3 described in JCPDS Card No. 84-1634. More specifically, the diffraction pattern of measurement point 1 (Fig. 35(A)) was the same as the diffraction pattern with an incident direction of [-1 -1 0] in the above crystal structure, and that of measurement point 2 (Fig. 35( Also, the measured values of the positional relationships (distance, angle) of the spots in the obtained diffraction pattern showed a good correspondence with the crystal structure of Li2MnO3 described in JCPDS Card No. 84-1634. More specifically, the diffraction pattern of measurement point 1 (Fig. 35(A)) was the same as the diffraction pattern with an incident direction of [-1 -1 0] in the above crystal structure, and that of measurement point 2 (Fig. 35( The diffraction pattern of B) showed good correspondence with the diffraction pattern with an incident direction of [3 2 -3]. On the right side of each figure, the distances and angles corresponding to JCPDS Card No. 84-1634 are shown. On the left side of each figure, the measured values are shown.

[0460] In addition, electron beam diffraction was observed for particles different from those in Fig. 39. Specifically, at measurement points 1 (*1) and 2 (*2) in the TEM photograph shown in Fig. 40, nanobeam electron diffraction was evaluated. Measurement point 2 shown in Fig. 40 is closer to the surface of the particle and is in the region within 10 nm from the surface of the particle. Measurement point 1 is a region closer to the inside of the particle compared to measurement point 2. The nanobeam electron diffraction results for each measurement point are shown in Fig. 41. Fig. 41(A) shows the nanobeam electron diffraction result of measurement point 1 shown in Fig. 40, and Fig. 41(B) shows that of measurement point 2.

[0461] In addition, the measured values of the positional relationships (distances, angles) of the spots in the obtained diffraction pattern showed good correspondence with the crystal structure of Li2MnO3 described in JCP DS Card No. 84-1634. More specifically, the diffraction pattern of measurement point 1 (Fig. 41(A)) corresponded well with the diffraction pattern with an incident direction of

[0100] in the above crystal structure, and the diffraction pattern of measurement point 2 (Fig. 41(B) ) corresponded well with the diffraction pattern with an incident direction of [3 2 -3]. On the right side of each figure, the distances and angles corresponding to JCPDS Card No. 84-1634 are shown. On the left side of each figure, the measured values are shown.

[0462] Here, as described in Embodiment 1, the first region and the second region are layered rock salt It preferably has a type structure, and the <1 1 0> orientation of the first region is parallel to the <3 2 -3> orientation of the second region. By these orientations being parallel it is possible to maintain approximately the in-plane arrangement of, for example, a layer containing lithium and manganese, or a layer of oxygen, while joining, so it can be said that the two regions have good alignment.

Example

[0463] In this example, the relationship between the surface area and characteristics of the particles of one aspect of the present invention will be described.

[0464] Regarding the step S15 shown in Example 1, the crushing conditions were examined, and the relationship with the surface area of the obtained particles was evaluated.

[0465] Particles of one aspect of the present invention were produced along steps S11 to S19 in FIG. 1 . Here, regarding the crushing step shown in step S15, using the crushing conditions shown in Table 2, samples Z-1 to sample Z-6 were produced. Also, regarding samples Z-4 to Z-6, the coating layer was not formed.

[0466]

Table 3

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

[0468] Next, electrodes were produced using the obtained samples Z-1 to Z-6. The production conditions of the electrodes are referred to Example 1.

[0469] Next, using the same electrolyte, separator, and counter electrode as the conditions shown in Example 1 with the produced electrodes a half cell was produced using a coin cell.

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

[0471] As the peripheral speed increased, the specific surface area tended to increase. Under the conditions in which the composition was performed, the larger the specific surface area, the higher the capacity. 4.0m 2 / g, the discharge capacity was 274mAh / g, and the specific surface area of sample Z-3 was 14 .8m 2 The discharge capacity was 291mAh / g, both of which were very high values. .

[0472] On the other hand, in the case of the sample without the coating layer, the specific surface area increases as the peripheral speed increases. However, sample Z-5 had a specific surface area of 14.6 m 2 / g, discharge capacity is 91mAh / g , and 30.3 m for sample Z-6. 2 The discharge capacity is low at 101mAh / g for 100mAh / g. The crushing treatment with the sieve may have resulted in a damaged layer being formed on the particle surface, or It is possible that part of the surface layer has been scraped off. By forming a coating layer, the surface area It was possible to increase the efficiency and obtain a high capacity. EXAMPLES

[0473] In this example, the "particles having lithium manganese composite oxide" of one embodiment of the present invention was used. Then, a thin storage battery described in Embodiment 2 was manufactured.

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

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

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

[0477] (Step S16) Next, the lithium manganese composite oxide after the crushing treatment was heat-treated and dried. After drying , the obtained powder was designated as sample A2. Thereafter, the obtained lithium manganese composite oxide was placed in a crucible and fired. The firing conditions were 8 00 °C for 3 hours in a dry air atmosphere of 10 L / min.

[0478] (Step S17) Next, a carbon-containing layer was formed on the obtained sample A2. First, with respect to 4 g of graphene oxide , 50 ml of water was added and kneaded using a kneader to prepare a dispersion solution of graphene oxide . Next, 200 g of sample A2 was added to the prepared dispersion solution, and 90 ml of water was further added and solid kneading was performed twice. The solid kneading was performed using a kneader at a rotation speed of 80 rpm, and the kneading time was 30 minutes per time and repeated twice. The obtained mixture was dried at 50 °C using a ventilation drying furnace, and then crushed in an alumina mortar to obtain sample B2, which is a lithium manganese composite oxide coated with graphene oxide.

[0479] (Step S18) Next, the graphene oxide coated on the surface of the lithium manganese composite oxide was reduced. Reduction Ascorbic acid was used as the agent, and an ethanol aqueous solution with a concentration of 80% by volume was used as the solvent. Based on the weight of the lithium manganese composite oxide coated with graphene oxide, 16.87 wt% of ascorbic acid and 3.9 wt% of lithium hydroxide were added to prepare a reducing solution. The obtained sample B2 was put into the reducing solution and treated at 60 °C for 3 hours for reduction.

[0480] (Step S19) Next, the solvent was separated from the obtained solution by a centrifuge, and the separated liquid was discarded. Then, the process of adding pure water for washing, performing centrifugation, and then discarding the separated liquid was repeated 4 times. The rotation speed of centrifugation was 9000 rpm, and the time for each time was 3 minutes. Next, pure water was added to the sample from which the solvent was separated and adjusted to a concentration of 121 g / l to obtain a solution. Then, the obtained solution was heated to 150 °C and spray-dried.

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

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

[0483] Next, a positive electrode of a storage battery was prepared using Sample C2. Sample C2 was used as the active material, acetylene black (AB) was used as the conductive aid, and PVdF was used as the binder. The mixing ratio of the active material, AB, and PVdF was active material:AB:PVdF = 90:5:5 (wei ght%).

[0484] Using a kneader, the active material, AB, PVdF, and NMP were kneaded to prepare a slurry. . Then, on an aluminum foil with a thickness of 20 μm that has undergone undercoating treatment, a slurry was applied to one side of the aluminum foil using a continuous coater. Then, after drying at 70 °C for 1 0 minutes using a drying furnace, it was dried at 90 °C for 10 minutes.

[0485] After that, further heat treatment was performed. As the heat treatment conditions, a treatment was carried out for 10 hours at 250 °C in a reduced-pressure atmosphere (1 KPa). Then, the press pressure was set to 1.5 MPa and the press temperature was set to 120 °C. Through the above steps, the positive electrode X2 having "particles having a lithium manganese composite oxide", which is one embodiment of the present invention, was obtained. The loading amount of the active material of the obtained positive electrode was 7.2 mg / cm 2 .

[0486] Next, using the fabricated positive electrode X2 and a negative electrode using graphite as the active material, a battery A, which is a thin battery shown in Embodiment 2, was fabricated, and the positive electrode X2 was aged. An aluminum film covered with a heat-sealing resin was used as the exterior of the battery A. As the electrolyte,

[0487] LiPF6 was used as the salt, and a solvent in which EC, DEC, and EMC were mixed was used as the solvent. In addition, PP was used for the separator.

[0488] Next, while applying a pressure of 20 MPa to the fabricated battery A using a press, charge and discharge was performed 3 times. The lower limit voltage of discharge was set to 2 V.

[0489] <Fabrication of the negative electrode> Next, a negative electrode used for the battery was fabricated. SiO was used as the active material, AB was used as the conductive assistant, and polyimide was used as the binder.

[0490] First, weigh SiO, AB, and the polyimide precursor so that the ratio of SiO:AB:polyimide precursor is 80:5:15 (weight%). Weigh SiO, AB, and the polyimide precursor. As the polyimide precursor, a solution with a concentration of 13.7 weight% using NMP as the solvent was used.

[0491] First, mix SiO and AB using a kneader. Then, gradually add NMP and perform solid kneading using a planetary type kneader to prepare a paste. The total amount of NMP added to prepare the paste was adjusted so that the solid content ratio of the paste was about 60%. Here, solid kneading refers to kneading at high viscosity. By performing solid kneading, the dispersibility of the active material and the conductive assistant can be enhanced.

[0492] Next, add the polyimide precursor solution using NMP as the solvent to the prepared paste and perform kneading using a kneader. Through the above steps, a slurry was prepared. The solid content ratio of the obtained slurry was 40 weight%.

[0493] Next, using a continuous coater, coat the slurry on one side of a rolled copper foil with a thickness of 18 μm. Then, evaporate the solvent by heat treatment using a drying furnace. As the heat treatment conditions, perform heat treatment at 50°C for 180 seconds, and then perform heat treatment at 75°C for 180 seconds. The negative electrode obtained through the above steps is designated as negative electrode Y. The loading amount of the active material of the obtained negative electrode Y was 1.9 mg / cm 2

[0494] Next, using the prepared negative electrode Y and a positive electrode using lithium cobaltate as the active material, a thin rechargeable battery B was fabricated, and the negative electrode Y was aged.

[0495] ​​​​​​​​​An aluminum film covered with a heat-sealing resin was...

Claims

1. having a composite oxide containing lithium and manganese, the composite oxide having a first region and a second region, the second region being located on the surface side of the first region and in the surface layer portion of the composite oxide, the first region and the second region having lithium and oxygen, the first region and the second region having manganese and an element represented by M, the element represented by M being a metal element selected from Ni, Ga, Fe, Mo, In, Nb, Nd, Co, Sm, Mg, Al, Ti, Cu, or Zn, Si, or P, a positive electrode active material for a lithium ion secondary battery, wherein a ratio of the number of oxygen atoms to the sum of the number of manganese atoms and the number of element M atoms in the second region is smaller than a ratio of the number of oxygen atoms to the sum of the number of manganese atoms and the number of element M atoms in the first region.

2. having a composite oxide containing lithium and manganese, the composite oxide having a first region and a second region, the second region being located on the surface side of the first region and in the surface layer portion of the composite oxide, the first region and the second region having lithium and oxygen, the first region and the second region having manganese and an element represented by M, the element represented by M being a metal element selected from Ni, Ga, Fe, Mo, In, Nb, Nd, Co, Sm, Mg, Al, Ti, Cu, or Zn, Si, or P, the first region having a first crystal with a layered rock salt type structure, the second region having a second crystal with a layered rock salt type structure, an orientation of the first crystal being different from an orientation of the second crystal, a positive electrode active material for a lithium ion secondary battery, wherein a ratio of the number of oxygen atoms to the sum of the number of manganese atoms and the number of element M atoms in the second region is smaller than a ratio of the number of oxygen atoms to the sum of the number of manganese atoms and the number of element M atoms in the first region.

3. having particles having a composite oxide containing lithium and manganese, the particles having a composite oxide having a first region, a second region, and a third region, the second region and the third region being located on the surface side of the first region and in the surface layer portion of the particles having the composite oxide, the third region being located on the surface side of the second region, the first region and the second region having lithium and oxygen, the first region and the second region having manganese and an element represented by M, The element represented by M is a metal element selected from Ni, Ga, Fe, Mo, In, Nb, Nd, Co, Sm, Mg, Al, Ti, Cu, or Zn, Si, or P, The third region has carbon and oxygen, The first region has a first crystal with a layered rock salt structure, The second region has a second crystal with a layered rock salt structure, The orientation of the first crystal is different from that of the second crystal, The ratio of the number of oxygen atoms to the sum of the number of manganese and element M atoms in the second region is smaller than the ratio of the number of oxygen atoms to the sum of the number of manganese and element M atoms in the first region, which is a positive electrode active material for a lithium ion secondary battery.

4. In claim 3, The thickness of the third region is 0.1 nm or more and 30 nm or less, which is a positive electrode active material for a lithium ion secondary battery.

5. In claim 3 or claim 4, The proportion of oxygen in the third region is 2 atomic % or more and 20 atomic % or less, which is a positive electrode active material for a lithium ion secondary battery.

6. In any one of claims 1 to 5, The thickness of the second region is 0.1 nm or more and 30 nm or less, which is a positive electrode active material for a lithium ion secondary battery.

7. It includes a positive electrode and a negative electrode, The positive electrode has a positive electrode active material and a conductive assistant, The positive electrode active material has a composite oxide containing lithium and manganese, The composite oxide has a first region and a second region, The second region is located on the surface side of the first region and in the surface layer part of the composite oxide, The first region and the second region have lithium and oxygen, The first region and the second region have manganese and an element represented by M, The element represented by M is a metal element selected from Ni, Ga, Fe, Mo, In, Nb, Nd, Co, Sm, Mg, Al, Ti, Cu, or Zn, Si, or P, The ratio of the number of oxygen atoms to the sum of the number of manganese and element M atoms in the second region is smaller than the ratio of the number of oxygen atoms to the sum of the number of manganese and element M atoms in the first region, The conductive assistant has carbon fiber or graphene, The negative electrode has a negative electrode active material, The negative electrode active material has a carbon-based material, which is a lithium ion secondary battery.

8. It includes a positive electrode and a negative electrode, The positive electrode has a positive electrode active material and a conductive assistant, The positive electrode active material has a composite oxide containing lithium and manganese, The composite oxide has a first region and a second region, The second region is located on the surface side of the first region and in the surface layer portion of the composite oxide, The first region and the second region have lithium and oxygen, The first region and the second region have manganese and an element represented by M, The element represented by M is a metal element selected from Ni, Ga, Fe, Mo, In, Nb, Nd, Co, Sm, Mg, Al, Ti, Cu, or Zn, Si, or P, The first region has a first crystal having a layered rock salt structure, The second region has a second crystal having a layered rock salt structure, The orientation of the first crystal is different from the orientation of the second crystal, The ratio of the number of oxygen atoms to the sum of the number of manganese atoms and the number of element M atoms in the second region is smaller than the ratio of the number of oxygen atoms to the sum of the number of manganese atoms and the number of element M atoms in the first region, The conductive assistant has carbon fiber or graphene, The negative electrode has a negative electrode active material, The negative electrode active material has a carbon-based material, a lithium ion secondary battery.

9. A positive electrode and a negative electrode, The positive electrode has a positive electrode active material and a conductive assistant, The positive electrode active material has particles having a composite oxide containing lithium and manganese, The particles having the composite oxide have a first region, a second region, and a third region, The second region and the third region are located on the surface side of the first region and in the surface layer portion of the particles having the composite oxide, The third region is located on the surface side of the second region, The first region and the second region have lithium and oxygen, The first region and the second region have manganese and an element represented by M, The element represented by M is a metal element selected from Ni, Ga, Fe, Mo, In, Nb, Nd, Co, Sm, Mg, Al, Ti, Cu, or Zn, Si, or P, The third region has carbon and oxygen, The first region has a first crystal having a layered rock salt structure, The second region has a second crystal having a layered rock salt structure, The orientation of the first crystal is different from the orientation of the second crystal, The ratio of the number of oxygen atoms to the sum of the number of manganese atoms and the number of atoms of element M in the second region is smaller than the ratio of the number of oxygen atoms to the sum of the number of manganese atoms and the number of atoms of element M in the first region. The conductive assistant has carbon fiber or graphene. The negative electrode has a negative electrode active material. The negative electrode active material has a carbon-based material, a lithium ion secondary battery.

10. In claim 9, The thickness of the third region is 0.1 nm or more and 30 nm or less, a lithium ion secondary battery.

11. In claim 9 or claim 10, The proportion of oxygen in the third region is 2 atomic% or more and 20 atomic% or less, a lithium ion secondary battery.

12. In any one of claims 7 to 11, The thickness of the second region is 0.1 nm or more and 30 nm or less, a lithium ion secondary battery.

13. In any one of claims 7 to 12, The carbon fiber is carbon fiber or carbon nanotube, a lithium ion secondary battery.

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