Collector for secondary battery

Abstract

To provide a novel electrode, a novel power storage device, an electrode of a large capacity, a power storage device having a large energy density, a power storage device having flexibility, a power storage device having a long life, a highly reliable power storage device, or a power storage device which is small in the worsening in characteristic when an external force is applied thereto repeatedly.SOLUTION: A collector hereof comprises a conductor having a sheet-like shape, of which the thickness is 800 nm or more and 2 0 μm or less, and the area is 25 mm2 or more and 10 m2 or less, in which the conductor has carbon and oxygen; the concentration of the carbon in the conductor is larger than 80 atomic%, and the concentration of the oxygen in the conductor is 2 atomic% or more and 20 atomic% or less.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an article, a method, or a manufacturing method. The present invention relates to a method, manufacture, or composition of matter. One embodiment of the present invention is a semiconductor device, a display device, a light-emitting device, a power storage device, a memory device, or any of these devices. In particular, one embodiment of the present invention relates to a power storage device and a driving method thereof, or a manufacturing method thereof. and a method for producing the same.

[0002] In this specification, the term "electricity storage device" refers to elements and devices in general that have an electricity storage function. That is why. [Background technology]

[0003] In recent years, secondary batteries such as lithium-ion secondary batteries, lithium-ion capacitors, air batteries, etc. In particular, the development of high-output, high-energy-density lithium-ion batteries has been in progress. Lithium-ion secondary batteries are used in mobile phones, smartphones, and laptops. Electronic devices such as portable information terminals, portable music players, digital cameras, and medical devices , Hybrid electric vehicle (HEV), Electric vehicle (EV), or Plug-in hybrid vehicle (P With the development of the semiconductor industry, next-generation clean energy vehicles such as hybrid electric vehicles (HEVs) are rapidly becoming Demand is expanding, and they have become an essential source of rechargeable energy in today's information society. It has become.

[0004] Graphene has also attracted a great deal of attention due to its excellent electrical conductivity, and is being used on a large scale. As shown in Non-Patent Document 1, graphene oxide (grap The compound obtained by reducing GO (r hene oxide) is called reduced GO (r It is sometimes called GO, and its physical properties are attracting attention.

[0005] The need for capacity of the power storage device is increasing year by year. For example, as shown in Patent Document 1, Development is underway to improve the electrodes of the device and increase its capacity. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent Publication No. 2012-009414 [Non-patent literature]

[0007] [Non-Patent Document 1] A. Bagri et al., “Structural evolution during the reduction of chemically derived graphene oxide”, NATURE CHEMISTRY, vol.2, 2010, pp.581-587. Summary of the Invention [Problem to be solved by the invention]

[0008] An object of one embodiment of the present invention is to provide a novel electrode. An object of one embodiment is to provide a novel power storage device.

[0009] Another object of one embodiment of the present invention is to provide an electrode with large capacitance. An object of one embodiment of the present invention is to provide a power storage device with high energy density. .

[0010] Another object of one embodiment of the present invention is to provide a flexible power storage device. Another object of one embodiment of the present invention is to provide a power storage device with a long lifetime. Another object of one embodiment of the present invention is to provide a highly reliable power storage device. According to one embodiment of the present invention, there is provided a power storage device in which deterioration in characteristics is small when an external force is repeatedly applied. One of our goals is to provide

[0011] The description of these problems does not preclude the existence of other problems. It is not necessary for one embodiment to solve all of these problems. The subject matter will be self-evident from the description, drawings, claims, etc. Other issues can be extracted from the drawings, claims, etc. [Means for solving the problem]

[0012] One embodiment of the present invention has a sheet shape and a thickness of 800 nm to 20 μm. The area is 25 mm 2 More than 10m 2 The carbon concentration is less than or equal to 1. , 80 atomic% or more, and the oxygen concentration is 2 atomic% or more and 20 atomic% or more. It is a conductor having a portion where the conductivity is omic % or less.

[0013] In the above configuration, the conductor has an electrical conductivity of 0.1 S / cm or more and 7 S / c It is preferred to have a portion that is m or less.

[0014] In the above structure, the conductor preferably has an aggregate of graphene. Here, having an aggregate of graphene means having a plurality of graphenes. Alternatively, the present invention has a plurality of graphene compounds.

[0015] In the above configuration, the conductor has a plurality of graphene layers of 2 to 100 layers, The length of the graphene in the longitudinal direction is preferably 50 nm or more and 100 μm or less. In the above configuration, the interlayer distance of the graphene is 0.335 nm or more and 0.7 nm or less. It is preferable that there is.

[0016] In the above structure, the concentration of oxygen in the conductor is measured by X-ray photoelectron spectroscopy. In the above structure, the conductor preferably has a bond between carbon and oxygen. is preferred.

[0017] In the above structure, the conductor may be an epoxy group, a carbonyl group, or a hydroxyl group bonded to carbon. It is preferable that the composition has at least one of the above.

[0018] In the above configuration, the conductor preferably contains sulfur in a range of 10 ppm to 5%. I wish.

[0019] Alternatively, one embodiment of the present invention has a positive electrode and a negative electrode, and either the positive electrode or the negative electrode is The present invention has a layer having any one of the above conductors and an active material, and the layer has at least It is an electricity storage device that is in contact with one surface.

[0020] Alternatively, one embodiment of the present invention includes a positive electrode and a negative electrode, and the positive electrode is any one of the above. The present invention relates to an energy storage device having the above-mentioned conductor.

[0021] Alternatively, one embodiment of the present invention includes a positive electrode and a negative electrode, and the positive electrode is any one of the above. The layer is in contact with at least one surface of the conductor, and the layer is a positive electrode active material. It is an energy storage device having a substance.

[0022] In the above-mentioned electricity storage device, the conductor is preferably laminated with a separator, The current collector is preferably wound.

[0023] Another embodiment of the present invention is an electronic device including the above power storage device.

[0024] In addition, the conductor of one embodiment of the present invention includes a plurality of graphene compounds that are partially overlapped with each other. Here, multiple graphene compounds are stacked while partially overlapping each other. When the graphene compound is formed into a single sheet, it is sometimes called a graphene compound sheet.

[0025] For example, in the conductor of one embodiment of the present invention, a plurality of graphene oxides are stacked so as to partially overlap each other. By doing so, the thickness is 50 nm or more and the area is 1 mm 2 The above sheet is prepared, and the sheet The conductor can be produced by subjecting the conductor to a reduction treatment of the carbon concentration. The concentration of oxygen is preferably greater than 80 atomic %, and the concentration of oxygen is preferably greater than 2 atomic %. It is preferable that the interlayer distance is 0.335 nm or more and 0.7 nm or less. It is preferable that the length is equal to or less than m.

[0026] Alternatively, in one embodiment of the present invention, a plurality of graphene oxides are stacked so as to partially overlap each other. This means that the thickness is 50 nm or more and the area is 1 mm 2 The above sheet is prepared, and The present invention relates to a method for producing a conductor, which comprises the steps of: The oxygen concentration is preferably 2 atomic % or more and 20 atomic % or more. tomic% or less, and the interlayer distance is 0.335 nm or more and 0.7 nm or less. It is preferable that: Effect of the Invention

[0027] According to one embodiment of the present invention, a novel electrode can be provided. Thus, a novel power storage device can be provided.

[0028] According to one embodiment of the present invention, an electrode having a large capacity can be provided. According to one embodiment, a power storage device with high energy density can be provided.

[0029] According to one embodiment of the present invention, a flexible power storage device can be provided. According to one embodiment of the present invention, a power storage device with a long lifetime can be provided. According to one embodiment of the present invention, a highly reliable power storage device can be provided. As a result, it is possible to provide an electricity storage device in which the characteristics are less deteriorated when an external force is repeatedly applied. Cut.

[0030] The description of these effects does not preclude the existence of other effects. An embodiment does not necessarily have to have all of these effects. The above will become apparent from the description in the specification, drawings, claims, etc. It is possible to extract other effects from the descriptions in the claims, etc. [Brief description of the drawings]

[0031] [Figure 1] FIG. 1 illustrates a part of a conductor according to one embodiment of the present invention. [Diagram 2] 1A to 1C are diagrams illustrating conductors according to one embodiment of the present invention. [Diagram 3] FIG. 1 is a diagram illustrating a graphene compound. [Figure 4] FIG. 1 illustrates a part of a conductor according to one embodiment of the present invention. [Diagram 5] FIG. 1 is a diagram illustrating a spray drying apparatus. [Figure 6] FIG. 2 illustrates a cross section of a power storage device. [Figure 7] FIG. 2 illustrates a cross section of a power storage device. [Figure 8] FIG. 2 illustrates a cross section of a power storage device. [Figure 9] FIG. 2 illustrates a cross section of a power storage device. [Figure 10] 1A to 1C are diagrams illustrating particles according to one embodiment of the present invention. [Figure 11] FIG. 4 is a diagram illustrating a part of a cross section of an electrode. [Figure 12] 1A and 1B are diagrams illustrating a power storage device. [Figure 13] 1A to 1C illustrate a method for manufacturing a power storage device. [Figure 14] 1A to 1C illustrate a method for manufacturing a power storage device. [Figure 15] 1A to 1C illustrate a power storage device and a method for manufacturing the power storage device. [Figure 16] 1A and 1B are diagrams illustrating a power storage device. [Figure 17] 1A and 1B are diagrams illustrating a power storage device. [Figure 18] FIG. 1 is a cross-sectional view of a power storage device. [Figure 19] 1A and 1B are diagrams illustrating a power storage device. [Figure 20] 1A and 1B are diagrams illustrating a power storage device. [Figure 21] FIG. 2 illustrates a cross section of a power storage device. [Figure 22] FIG. 2 illustrates a cross section of a power storage device. [Diagram 23] FIG. 2 illustrates a cross section of a power storage device. [Figure 24] 1A and 1B are diagrams illustrating a power storage device. [Diagram 25] FIG. 4 is a diagram for explaining the radius of curvature of a surface. [Figure 26] FIG. 2 is a diagram for explaining the radius of curvature of a film. [Figure 27] 1A and 1B are diagrams for explaining examples of power storage systems. [Figure 28] 1A and 1B are diagrams for explaining examples of power storage systems. [Figure 29] 1A and 1B are diagrams for explaining examples of power storage systems. [Diagram 30] 1A to 1C are diagrams illustrating examples of electronic devices. [Diagram 31] 1A to 1C are diagrams illustrating examples of electronic devices. [Diagram 32] 1A to 1C are diagrams illustrating examples of electronic devices. [Diagram 33] 1A to 1C are diagrams illustrating examples of electronic devices. [Diagram 34] FIG. 1 is a block diagram illustrating one embodiment of the present invention. [Diagram 35] FIG. 1 is a conceptual diagram illustrating one embodiment of the present invention. [Diagram 36] FIG. 1 is a circuit diagram illustrating one embodiment of the present invention. [Figure 37] FIG. 1 is a circuit diagram illustrating one embodiment of the present invention. [Figure 38] FIG. 1 is a conceptual diagram illustrating one embodiment of the present invention. [Figure 39] FIG. 1 is a block diagram illustrating one embodiment of the present invention. [Diagram 40] 1 is a flowchart illustrating one embodiment of the present invention. [Diagram 41] Photographs showing one embodiment of the present invention. [Diagram 42] Photographs showing one embodiment of the present invention. [Diagram 43] Photographs showing one embodiment of the present invention. [Diagram 44] FIG. [Diagram 45] FIG. [Diagram 46] FIG. [Figure 47] FIG. [Figure 48] FIG. [Figure 49] FIG. [Figure 50]FIG. 1 shows the results of FT-IR evaluation. [Figure 51] FIG. [Figure 52] FIG. [Figure 53] Optical microscope photograph. [Figure 54] Optical micrographs and SEM observations. [Figure 55] Optical microscope photograph. [Figure 56] SEM observation results. [Figure 57] Cross-sectional TEM observation results. [Figure 58] Cross-sectional TEM observation results. [Figure 59] Photographs showing experimental results. [Figure 60] FIG. [Figure 61] FIG. 1 is a top view illustrating one embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0032] The present invention will be described in detail below with reference to the accompanying drawings. The present invention is not limited to these descriptions, and various modifications in form and details are possible by those skilled in the art. Therefore, the present invention should not be construed as being limited to the description of the following embodiments. It is not something that is done.

[0033] In each figure described in this specification, the size and other details of each element such as a film, layer, substrate, region, etc. The thicknesses and the like may be exaggerated for clarity of explanation. The components are not limited by their size, nor are they limited by the relative size between each other. stomach.

[0034] In this specification, ordinal numbers such as 1st, 2nd, etc. are used for convenience. It does not indicate the order of processes or the order of layers. "The" can be appropriately replaced with "the second" or "the third" etc. Ordinal numbers described in the specification and the like and ordinal numbers used to specify one aspect of the present invention may not match.

[0035] In the configuration of the present invention described in this specification, etc., The same reference numerals are used for the same parts in different drawings, and the repeated explanations are omitted. In addition, when referring to parts having similar functions, the same hatch pattern is used and special symbols are attached. This may not be the case.

[0036] In this specification, both the positive and negative electrodes for a power storage device are collectively referred to as electrodes. In this case, the electrode refers to at least one of the positive electrode and the negative electrode. do.

[0037] Here, the charging and discharging rates of the storage device will be described. For example, When charging a secondary battery (Ah) at a constant current, a charge rate of 1C means that charging will finish in exactly one hour. The current value I [A] at which the charge ends is 0.2C, and a charge rate of 0.2C is I / 5 [A] (i.e. (That is, the current value at which charging is completed in exactly 5 hours.) Similarly, a discharge rate of 1C is is the current value I [A] at which the discharge ends in exactly one hour, and the discharge rate is 0.2C. This is I / 5[A] (i.e., the current value at which the discharge ends in exactly 5 hours). .

[0038] (Embodiment 1) In this embodiment, a graphene compound according to one embodiment of the present invention and a graphene A conductor having an anthracene compound will now be described.

[0039] Graphene is a single atomic layer of carbon atoms with π bonds between the carbon atoms. When two to 100 layers of graphene are stacked together, they are sometimes called multi-graphene. Graphene and multi-graphene are, for example, The length is 50 nm or more and 100 μm or less, or 800 nm or more and 50 μm or less.

[0040] In the present specification and the like, a compound having graphene or multi-graphene as a basic skeleton The material is called "graphene compound" ("graphene compound"). Graphene compounds include graphene and multi-graphene. nothing.

[0041] The graphene compound will be described in detail below.

[0042] For example, graphene or multi-graphene is a graphene compound having atoms other than carbon, or a compound modified with an atomic group having an atom other than carbon. In the present study, multi-graphene was modified with carbon-based atomic groups such as alkyl and alkylene groups. In addition, the compound may be a compound having an atomic group that modifies the graphene or multi-graphene. In this specification, modification may be referred to as a substituent, a functional group, a characteristic group, or the like. means a compound obtained by a substitution reaction, an addition reaction or other reaction to produce graphene, multi-graphene, Graphene compounds or graphene oxide (described below) that contain atoms other than carbon or This refers to the introduction of an atomic group having an atom of the formula:

[0043] The front and back surfaces of graphene are modified with different atoms or atomic groups. In the case of multi-graphene, each layer may be modified with a different atom or atomic group. It may be possible.

[0044] An example of graphene modified with the above-mentioned atoms or atomic groups is oxygen or The graphene or multi-graphene modified with a functional group containing oxygen is an example. Examples of the functional group include an epoxy group, a carbonyl group such as a carboxy group, a hydroxyl group, or The lactol group is an example of a group modified with oxygen or a functional group having oxygen. The graphene compound may be called graphene oxide. Also includes multi-layer graphene oxide.

[0045] Next, an example of a method for producing graphene oxide will be described. Alternatively, graphene oxide can be obtained by oxidizing graphene or multi-graphene. Graphite oxide can be obtained by separating the layers of graphite oxide. Here, the graphene oxide can be further oxidized to the above-mentioned atom or atoms. The group may be modified.

[0046] Methods for producing graphene oxide include, for example, the Hummers method and the Modified There are various synthesis methods, such as the Hummers method or oxidation of graphite.

[0047] For example, the Hummers method and the Modified Hummers method are This is a method of forming graphite oxide by oxidizing graphite such as carbide. The graphite oxide is made by oxidizing the graphite in places to form carbonyl groups, It is a compound having functional groups such as carboxyl groups, hydroxyl groups, and lactol groups bonded thereto, and has a graph The crystallinity of the quartz is impaired and the distance between the layers is large. This allows the layers to be easily separated to obtain graphene oxide.

[0048] Here, we explain an example of a method for producing graphene oxide using the modified Hummers method. Graphite powder is added to a sulfuric acid solution of potassium permanganate to cause an oxidation reaction. Form a mixture containing graphite oxide, which is the carbon part of graphite. Oxidation gives rise to functional groups such as epoxy groups, carbonyl groups, carboxy groups, and hydroxyl groups. Therefore, the interlayer distance of graphene oxide is longer than that of graphite. By applying ultrasonic vibration to a mixture containing graphite, graphite oxide with a long interlayer distance was produced. The graphene oxide can be separated by cleaving the sintered material, and the graphene oxide-containing dispersion can be obtained. A liquid can be formed.

[0049] By producing graphene oxide using the above-mentioned modified Hummers method, For example, the resulting graphene oxide may contain elements such as sulfur and nitrogen.

[0050] The concentration of sulfur in the graphene compound of one embodiment of the present invention is preferably, for example, 5% or less. , 3% or less is more preferable.

[0051] The graphene compound according to one embodiment of the present invention may have a concentration of, for example, 10 ppm or more and 5% or less, or 10 It may have between 0 ppm and 3%, or between 0.1% and 3% sulfur.

[0052] The concentration of sulfur in the graphene compound can be evaluated using elemental analysis such as XPS. It can be valued.

[0053] In addition, the graphene compound according to one embodiment of the present invention contains, for example, 0.1% or more and 3% or less of nitrogen. This may be the case.

[0054] The compound obtained by reducing graphene oxide is called "RGO (Reduced Graphene Oxide)." Here, RGO is referred to as “RGO-based ethylene oxide” as shown in Non-Patent Document 1. It is sometimes written as "rGO". Note that RGO has no oxygen in graphene oxide. In some cases, not all of the oxygen atoms are removed, and some of the oxygen atoms or atomic groups containing oxygen remain bonded. For example, RGO has carbonyl groups such as epoxy groups, carboxyl groups, or hydroxyl groups. The functional groups may include the above.

[0055] Graphene compounds are composed of multiple graphene compounds that overlap partially to form a single sheet. Such a graphene compound may be called a graphene compound sheet. The graphene compound sheet may have a thickness of, for example, 0.33 nm or more and 10 mm or less. More preferably, the graphene compound has a region larger than 0.34 nm and smaller than 10 μm. A group is an atom other than carbon, an atomic group containing atoms other than carbon, or a carbon atom such as an alkyl group. The graphene compound sheet may be modified with a main atomic group or the like. Each of the multiple layers may be modified with a different atom or atomic group.

[0056] Graphene compounds are composed of not only six-membered rings made of carbon, but also five-membered rings made of carbon and In this case, in the vicinity of the seven or more membered ring, In this case, there may be a region through which ions can pass. ions of alkali metals other than lithium, or ions used in electrolytes. anions and cations contained in the electrolyte, and anions and cations contained in the electrolyte. .

[0057] For example, a plurality of graphene compounds may be gathered together to form a sheet shape. Graphene compounds have a planar shape, which allows for surface contact.

[0058] Graphene compounds can be highly conductive even when they are thin, and can be grapheneized by surface contact. The contact area between the graphene compound and the active material or between the graphene compound and the active material can be increased. Therefore, even if the amount per volume is small, a conductive path can be formed efficiently.

[0059] In addition, a graphene compound can be used as an insulator. For example, a graphene compound The sheet can be used as a sheet-like insulator. For example, graphene oxide is In some cases, the insulating properties are higher than those of non-oxidized graphene compounds. Modified graphene compounds can improve their insulating properties depending on the type of atomic group modified. It may be possible.

[0060] FIG. 3(A) is a schematic diagram illustrating a single layer of graphene. FIG. 3(B) is a schematic diagram illustrating a single layer of graphene. The following shows examples of the case where functional groups such as epoxy groups, carboxy groups, and hydroxyl groups are added to the above. FIG. 3B is just an example, and the graphene to which a functional group is added is not limited to this.

[0061] <Conductor> FIG. 2 shows an external view of a conductor 201 according to one embodiment of the present invention. The conductor 201 is a sheet-shaped It is preferred that the shape is

[0062] The conductor 201 preferably comprises a graphene compound.

[0063] Here, the thickness of the conductor 201 is, for example, 0.33 nm or more and 100 μm or less, or 50 nm or more and 100 μm or less, or 800 nm or more and 20 μm or less.

[0064] The area of ​​the conductor 201 is, for example, 1 mm 2 More than 100m 2 Below, 25mm 2 Over 10 m 2 Below, 100mm 2 More than 3m 2 The following is acceptable.

[0065] The conductive material 201 will be described in more detail below. The region 202 shown by the dashed line in FIG. FIG. 1(A) shows a part of a cross section of a conductor 201. FIG. 1(B) is an enlarged view of a region 202. FIG. 1B is an enlarged view of the region 202a shown in FIG. 1A. The region 202a is a region including a plurality of graphs. It is preferable that the graphene compound 211 is partially It is preferable that the graphene compounds are stacked together. The resulting material may be called a graphene compound sheet. It is preferable to use a phenyl compound sheet.

[0066] Here, the length of one side of the graphene compound (also called the flake size) is The thickness is 50 nm or more and 100 μm or less, and preferably 800 nm or more and 20 μm or less.

[0067] A graphene compound sheet in which multiple graphene compounds are stacked can be formed by, for example, stacking adjacent graphene compounds. There may be an area between the phenyl compounds through which ions can pass. The graphene compound sheet may have excellent ion conductivity. In some cases, the material may be prone to adsorbing ions.

[0068] In addition, a graphene compound sheet in which multiple graphene compounds are stacked is stacked in a plane. The graphene compounds can slide against each other and deform when an external force is applied. It is considered that there are cases where cracks are less likely to occur.

[0069] Here, an example of a top view showing a part of the conductor 201 is shown in FIG. The compound 211 is stacked on top of one another. Therefore, the surface of the conductor 201 is graphite. In some cases, the surface of the conductor 201 has a step corresponding to the thickness of the silicon compound. The area of ​​the flat area may be approximately equal to or smaller than the step. In some cases, the area of ​​the compound may correspond to the area of ​​the

[0070] An example of the region 202a different from that shown in FIG. 1(B) is shown in FIG. 4(A) and FIG. 4(B). .

[0071] The conductor 201 contains a graphene compound, which makes the conductor 201 flexible and deformable. In addition, since the conductor 201 contains a graphene compound, This may increase the mechanical strength of the conductor 201.

[0072] In addition, the conductor 201 contains graphene or multi-graphene as the graphene compound. By having this, the conductivity of the conductor 201 can be increased.

[0073] The electrical conductivity of the conductor 201 according to one embodiment of the present invention is preferably 0.1 S / cm or more and 10 7 S / cm or less, more preferably 1S / cm or more to 10 6 S / cm or less, more preferably 10 S / cm or more 10 6 Here, the electrical conductivity of the conductor 201 is, for example, When the electric conductor 201 is in a sheet form, terminals are placed on the sheet surface and measurement is performed using the four-terminal method. It is possible.

[0074] An example of the interlayer distance of the graphene compound 211 in the conductor 201 is shown. The interlayer distance of the compound 211 is, for example, 0.335 nm or more and 0.7 nm or less, or 0.34 nm or more and 0.6 nm or less, or 0.34 nm or more and 0.5 nm or less, Alternatively, the graphene compound may have a diameter greater than 0.34 nm and smaller than 0.44 nm. Methods for calculating the interlayer distance of 211 include XRD, TEM, and the like.

[0075] Here, in TEM observation, observation of a very small area, for example, an area of ​​several nm to several μm square, is performed. In comparison, XRD evaluation evaluates average information over a wider range. It may be possible.

[0076] Next, the ratio of oxygen contained in the conductor 201 is measured by, for example, XPS (X-ray photoelectron spectroscopy), ED The oxygen ratio of the conductor 201 can be measured by XPS. In this case, the content is 2 atomic % or more and 20 atomic % or less of the entire conductor 201, preferably is 2 atomic% or more and 11 atomic% or less, more preferably 3 atomic% or more In addition, when the conductor 201 is measured by XPS, By analyzing the spectrum of binding energy corresponding to C1s through waveform separation, For the entire spectrum of s, sp 2 The ratio of the peaks that indicate Here, in the conductor 201, sp 2 The proportion of C1s in total It is preferable that the range is 50% to 90% of the spectrum.

[0077] The proportion of carbon in the conductor 201 is 80% or more relative to the entire conductor 201. The carbon ratio can be evaluated using, for example, XPS, EDX, etc. can be done.

[0078] The oxygen ratio of the graphene compound 211 in the conductor 201 is measured by XPS. The amount of the conductive material 201 is 2 atomic % or more and 20 atomic % or less, preferably 2 atomic % or less. omic% or more and 11 atomic% or less, more preferably 3 atomic% or more and 10 atomic% or less In addition, the carbon bonds in the graphene compound 211 are The ratio of double bonds is preferably, for example, 50% or more and 90% or less. In this case, for example, when measured by XPS, the spectrum of binding energies corresponding to the C1s of carbon is By analyzing the waveform of the C1s signal, 2 Show In some cases, the proportion of the peaks that correspond to the N peaks can be estimated as the area ratio. At MR 13 For example, when evaluating the C spectrum, the chemical shift is 130 ppm to 14 A peak suggesting a carbon double bond can be observed between 0 ppm and 10 ppm or in the vicinity. For example, COC bonds can be set between 50 ppm and 60 ppm or in the vicinity. , 70 ppm to 80 ppm or thereabouts, A peak indicating this can be observed. 2 The peaks that indicate this are, for example, those observed by NMR. The ratio of the area of ​​the peaks indicating carbon double bonds to the area of ​​all peaks showing carbon double bonds. For example, the sum of all peaks in the range of -50 ppm to 250 ppm may be calculated. Alternatively, the area of ​​the peak indicating a carbon double bond may be calculated as a ratio of the area of ​​the peak indicating a carbon double bond to the area of ​​the peak indicating a carbon double bond.

[0079] The ratio of carbon in the graphene compound 211 in the conductor 201 is The carbon content is preferably greater than 80% of the total. It can be evaluated using DX, etc.

[0080] <Interlayer compound> Alternatively, the conductor 201 may have a graphene compound having molecules or ions between layers. An intercalation compound may be used. When the graphene compound is an intercalation compound, the intercalation compound may be a The electrical conductivity can change depending on the type of molecules or ions. For example, In some cases, the electrical conductivity of the material can be increased. In addition, the size of the molecules and ions between the layers, Depending on the amount and content, the interlayer distance may increase.

[0081] <Method of manufacturing conductor> As an example, a method for producing the conductor 201 having the graphene compound 211 will be described below. do.

[0082] First, the graphene compound sheet 222 is prepared. The graphene compound sheet 222 is The material is a graphene compound, and it is produced using methods such as spray drying and coating. As an example, a graphene oxide dispersion is used as the raw material, and a spray d A graphene compound sheet 222 having graphene oxide is produced by the method A. At least a part of the graphene oxide contained in the graphene oxide dispersion is a multi-layer graphene oxide. It may also be a .

[0083] Using a graphene oxide dispersion as the raw material, multiple oxide films were formed on a plate using the spray drying method. Graphene is formed to obtain a graphene compound sheet 222 having graphene oxide. In the spray drying method, the film can be obtained by adjusting the film formation time, the concentration of the dispersion liquid, etc. In some cases, it may be possible to control the thickness of the graphene compound sheet to be produced, and the graphene compound according to one embodiment of the present invention may be used. The graphene compound sheet obtained is suitable for the production of graphene compound sheets. The solvent used for the dispersion of graphene oxide is preferably a polar solvent. For example, water, NMP, etc. can be used.

[0084] A schematic diagram of the spray dryer 280 is shown in FIG. The device has a chamber 281 and a nozzle 282. The nozzle 282 is connected to a tube 283. The dispersion liquid 284 is supplied from the nozzle 282 into the chamber 281. The nozzle 282 is connected to a heater 285. Here, the nozzle in the chamber 281 may be heated by the heater 285. The area close to 282, for example the area surrounded by the two-dot chain line in FIG. 5(A), is also heated. When a graphene oxide dispersion liquid is used as the dispersion liquid 284, the graphene oxide dispersion liquid is supplied. A part of the graphene oxide is collected as powder in a collection container 286 via a chamber 281. A part of the graphene compound is deposited on the wall surface of the chamber 281 as a graphene compound sheet 222. Here, the atmosphere in the chamber 281 is circulated by an aspirator or the like through a path indicated by an arrow 288. It may be sucked by.

[0085] Alternatively, a substrate is placed in the chamber 281, and a graphene compound sheet is placed on the substrate. The substrate may be flat or curved. For example, the nozzle 282 may be arranged parallel to the nozzle 282 or at an angle. In FIG. 5B, the substrate 287 is placed perpendicular to the nozzle 282. An example of forming a graphene compound sheet 222 is shown above. When film thickness uniformity can be improved by depositing the film while moving the film to the right Alternatively, the substrate 287 may be moved left and right. You may move both 87s.

[0086] The graphene compound sheet 222 thus produced has a 7° It is preferable that the peak is in the range of 10° or more. Alternatively, a peak may be, for example, a local maximum value.

[0087] Here, the interlayer distance of the graphene compound sheet 222 is, for example, greater than 0.8 nm and nm or less, or between 0.85 nm and 1.3 nm.

[0088] Here, in TEM observation, observation of a very small area, for example, an area of ​​several nm to several μm square, is performed. In comparison, XRD evaluation provides average information over a wider range, e.g. can be evaluated.

[0089] The interlayer distance observed by TEM is smaller than that calculated from XRD evaluation. For example, in the graphene compound sheet 222, The interlayer distance may be less than 0.5 nm.

[0090] Next, the graphene compound sheet 222 is subjected to a reduction treatment to obtain the conductor 201. The conductor 201 can also be called a graphene compound sheet. By subjecting the graphene compound sheet 22 to reduction, the graphene oxide contained in the graphene compound sheet 222 is Therefore, the conductor 201 is a graphene compound. The sheet-shaped conductor 201 is obtained by the above steps. For example, a sheet-like conductor 201 may be processed by cutting or the like to form a strip-like conductor 201.

[0091] The reduction process can be carried out by chemical reduction, which uses a reaction with a reducing agent, or by heat treatment. Thermal reduction or the like can be used.

[0092] Chemical reduction is explained. Reducing agents are ascorbic acid, hydrazine, and dimethyl Hydrazine, hydroquinone, sodium borohydride (NaBH4), aluminum hydride Lithium (LiAlH4), N,N-diethylhydroxylamine or their derivatives For example, ascorbic acid and hydroquinone can be used in combination with hydrazine and Its reducing power is weaker than that of sodium borohydride, making it safer and easier to use industrially. It is preferable in this case.

[0093] The solvent may be a polar solvent. Any solvent capable of dissolving the reducing agent may be used. The material is not limited to water, methanol, ethanol, acetone, tetrahydrofuran, etc. THF, dimethylformamide (DMF), 1-methyl-2-pyrrolidone ( NMP) and dimethyl sulfoxide (DMSO), ethylene glycol, diethylene glycol Licorice and glycerin can be used alone or in a mixture of two or more thereof.

[0094] The reducing solution containing a reducing agent and a solvent is a mixture of ethanol and ascorbic acid. Alternatively, a mixture of water, ascorbic acid and lithium hydroxide can be used.

[0095] Graphene oxide is protonated by ascorbic acid. H2O is then removed. By removing the graphene oxide, the graphene oxide is reduced.

[0096] The reduction temperature of the chemical reduction is, for example, from room temperature to 100° C., more preferably from 40° C. to 70° C. The treatment time can be set to 3 minutes or more and 10 hours or less.

[0097] After the reduction treatment, cleaning may be performed. For example, cleaning may be performed using a solvent such as that contained in the reduction solution. The solvent may be the same as that contained in the reducing solution, or A different solution may be used. Washing may be followed by drying.

[0098] Next, the thermal reduction will be described. The thermal reduction step is carried out at a temperature of, for example, 50° C. or higher and lower than 500° C. It is preferable to carry out the treatment at a temperature of 120° C. or more and 400° C. or less for 1 hour or more and 48 hours or less. The reaction may be carried out under reduced pressure (vacuum) or in a reducing atmosphere, or at atmospheric pressure. The gas may be air, nitrogen or other inert gas.

[0099] Here, when the conductor 201 obtained after reduction was evaluated by XRD, for example, it had a temperature of 21° It is preferable that the peak is in the range of 27° or more.

[0100] (Embodiment 2) In this embodiment, an example in which the conductor 201 of one embodiment of the present invention is used as an electrode will be described. 201 has a graphene compound 211 .

[0101] The conductor 201 of one embodiment of the present invention preferably functions as an active material of an electrode. That is, it is preferable that the conductor 201 contributes to the charging reaction or discharging reaction. When the conductor 201 of one embodiment is used as an electrode for a power storage device, the conductor 201 is reduced in oxidation. In this case, the redox reaction may involve the transfer of electrons. As a specific example, the redox reaction is a reaction between an ion, such as an anion or a cation, and Refers to the transfer of electrons during a reaction.

[0102] Alternatively, the conductor 201 according to one embodiment of the present invention can be formed on its surface as an electric double layer. Therefore, the conductor of one embodiment of the present invention can be used as an electrode of a capacitor. For example, the surface area of ​​the electrode may be larger than that of graphite. By using the same, the capacity of the power storage device can be increased.

[0103] The conductor 201 may be used as a current collector of an electrode. The electrode may have a conductor 201 and an active material other than the conductor 201. By using it as a current collector, it is possible to make the current collector thinner, which reduces the weight of the electrode. In addition, the electrodes may be easily deformed.

[0104] An example of the electrode will be described below.

[0105] <Electrode example 1> The inventors have reported that when the conductor 201 of one embodiment of the present invention is used as an electrode for a power storage device, As will be described in detail in the following examples, the conductor 201 is When used as an electrode, it has been reported that a discharge capacity of about 100 mAh / g can be obtained. Here, the discharge capacity of the conductor 201 is preferably 10 mAh / g or more, for example. More preferably, it is 40 mAh / g or more.

[0106] An example in which a conductor 201 of one embodiment of the present invention is used as an electrode for a power storage device is shown. The graphene compound 211 is the same as that of the above embodiment. It can be referred to.

[0107] The power storage device 100 shown in FIG. 6A includes a conductor 201, a separator 107, and an electrode 15. The separator 107 is sandwiched between the conductor 201 and the electrode 151. The electrochemical device 100 preferably has an electrolyte (not shown) between the conductor 201 and the electrode 151. As shown in FIG. 6B, the power storage device 100 includes a separator 107 sandwiched between the separator 107 and the power storage device 100. There may be a plurality of pairs of electrodes 151 and conductors 201 facing each other. For example, the electrodes 151 may be A current collector and a first layer on the current collector, the first layer having an active material. The components of the electrode 151 will be described in detail below.

[0108] The power storage device 100 shown in FIG. 7A includes a conductor 201, an electrolyte 158, and an electrode 151. The electrolyte 158 is sandwiched between the conductor 201 and the electrode 151. It is preferable to use, for example, a solid electrolyte as the electrolyte 158. 7B, the electricity storage device 100 is in contact with both the electrolyte 158 There may be a plurality of pairs of electrodes 151 and conductors 201 facing each other with the electrode 151 and conductor 201 sandwiched therebetween.

[0109] Here, by using a graphene compound sheet as the conductor 201, the current collector and the active Therefore, compared with the case where an active material is provided on a current collector such as a metal foil, This makes it possible to increase the capacity of the power storage device.

[0110] <Method of manufacturing conductor> Here, for example, a sheet-like or strip-like separator is used as the separator 107, and the separator 107 is conductive. The conductor 201 may be formed on at least one of the surfaces of the separator 107. The method for forming 201 may be, for example, a spray-dry method, a coating method, or the like. The coating method will be described later.

[0111] The electrolyte and the separator will be described in detail in the following embodiment. It is sufficient to use the

[0112] <Electrode example 2> Next, a conductor having the conductor 201 of one embodiment of the present invention and an active material different from the conductor 201 was 8 shows an example of an electrode. The electrode 101 shown in FIG. 8 includes a conductor 201 and a layer 102. The layer 102 has an active material 103. The layer 102 is provided on at least one surface of the conductor 201. In FIG. 8A, the layer 102 is provided on one side of the conductor 201. In FIG. 8B, the layer 102 is provided on both sides of the conductor 201.

[0113] The power storage device 100 shown in FIG. 9A includes an electrode 101, an electrode 151, and a separator 107. As shown in FIG. 9B, the power storage device 100 has a separator 107 sandwiched therebetween. The power storage device 10 shown in FIG. It is preferable that the electrode 101 and the electrode 151 are provided with an electrolyte (not shown). The energy storage device 100 may have an electrolyte 158 between the electrode 101 and the electrode 151 .

[0114] The layer 102 may contain a conductive additive, a binder, and the like.

[0115] When the electrode 101 is a positive electrode, the layer 102 has a positive electrode active material as the active material 103. In addition, when the electrode 101 is a negative electrode, the layer 102 is preferably It is preferable that the negative electrode has an active material.

[0116] In addition, when the electrode 101 is a positive electrode, the electrode 151 uses a negative electrode active material as an active material, When the electrode 101 is a negative electrode, the electrode 151 may have a positive electrode active material as an active material. preferable.

[0117] The electrode 151 may, for example, include a current collector and a first layer on the current collector. It is preferable that the first layer contains an active material. The first layer may contain a conductive assistant, a binder, etc. good.

[0118] The current collector of the electrode 151 may be made of stainless steel, gold, platinum, aluminum, titanium, or the like. Materials with high electrical conductivity, such as metals and their alloys, can be used. When used in a positive electrode, it is preferable that the current collector does not dissolve at the potential of the positive electrode. In the case of silicon, it is preferable that the silicon does not alloy with carrier ions such as lithium. Elements that improve heat resistance, such as zinc, titanium, neodymium, scandium, and molybdenum, are added. Aluminum alloys with added silicide can be used. The metal element may be a metal element that reacts with silicon to form a silicide. The elements include zirconium, titanium, hafnium, vanadium, niobium, tantalum, and chromium. The materials are aluminum, molybdenum, tungsten, cobalt, nickel, etc. The current collector is in foil, plate ( Sheet, mesh, punched metal, expanded metal, and other shapes can be used as appropriate. It is preferable to use a current collector having a thickness of 5 μm or more and 30 μm or less. The conductor 201 may be used as a current collector of the electrode 151 .

[0119] As the positive electrode active material, for example, an olivine type crystal structure, a layered rock salt type crystal structure, or a spin For example, a composite oxide having a Nemell type crystal structure can be used.

[0120] Positive electrode active materials include LiFeO2, LiCoO2, LiNiO2, LiMn2O4, and V Compounds such as 2O5, Cr2O5, and MnO2 can be used. In particular, LiCoO2 , large capacity, more stable in air than LiNiO2, It is preferable because it has the advantage of being thermally stable. The lithium-containing material has a spinel-type crystal structure containing calcium phosphate and a small amount of lithium nickel oxide. (LiNiO2 and LiNi 1-x M x When O2 (M=Co, Al, etc.) is mixed, This is preferable because it is possible to improve the characteristics of a secondary battery using this.

[0121] For example, the average particle size of the primary particles of the positive electrode active material is 5 nm or more and 50 μm or less. It is preferable that the specific surface area is 500 nm or more, and more preferable that the specific surface area is 500 nm or less. m 2 / g or more 15m 2 The average particle size of the secondary particles is preferably: The average particle size is preferably 5 μm or more and 50 μm or less. Observation using a microscope or TEM, or particle size distribution meter using laser diffraction / scattering method, etc. The specific surface area can be measured by a gas adsorption method.

[0122] In addition, the positive electrode active material is Li a Mn b M c O d Lithium ion can be expressed as In this case, the element M is any element other than lithium or manganese. It is preferable to use a metal element selected from the group consisting of silicon and phosphorus, and nickel is preferably used. It is more preferable to measure the entire particle of the lithium manganese composite oxide. When the voltage is applied <a / (b+c)<2、かつc>, the value is 0.0 and 0.26≦(b+c) / d<0.5. In order to realize high capacity, it is preferable that the crystal structure is ​The lithium manganese composite oxide has regions with different crystal orientations or oxygen contents. In order to obtain such a lithium manganese composite oxide, it is preferable that, for example, 1.6≦ It is preferable that a≦1.848, 0.19≦c / b≦0.935, and 2.5≦d≦3. In addition, Li 1.68 Mn 0.8062 Ni 0.318 The formula for the compound is O3. It is particularly preferable to use lithium manganese composite oxide. 1. 68 Mn 0.8062 Ni 0.318 Lithium manganese composite with the formula O3 The oxide is the ratio (molar ratio) of the amount of raw materials, Li2CO3:MnCO3:NiO=0 Lithium manganese oxide composite formed by mixing 0.84:0.8062:0.318 Therefore, the lithium manganese composite oxide has the composition formula Li 1.68 Mn 0.80 62 Ni 0.318 It is represented by O3, but the composition can deviate from this.

[0123] The composition of metals, silicon, phosphorus, etc. of the entire lithium manganese composite oxide particle is, for example, For example, it can be measured using an ICP-MS (inductively coupled plasma mass spectrometer). The oxygen composition of the entire lithium manganese oxide particle was measured using, for example, EDX (energy dispersion It can also be measured using ICP-MS analysis. This can be determined by using valence evaluation from melt gas analysis and XAFS (X-ray absorption fine structure) analysis. The lithium manganese composite oxide is a material that contains at least lithium and manganese. It refers to oxides containing chromium, cobalt, aluminum, nickel, iron, magnesium, Molybdenum, zinc, indium, gallium, copper, titanium, niobium, silicon, and phosphorus It may contain at least one element selected from the group consisting of:

[0124] Lithium manganese composite oxide having regions with different crystal structures, crystal orientations or oxygen contents An example of a cross-section of a particle of an object is shown in Figure 10.

[0125] As shown in FIG. 10(A), the crystal structure, crystal orientation, or oxygen content of the regions are different. The lithium manganese composite oxide has a region 331, a region 332, and a region 333. It is preferable that the region 332 contacts at least a part of the outside of the region 331. The side indicates that it is closer to the surface of the particle. Also, region 333 indicates that the lithium manganese composite It is preferred to have a region that coincides with the surface of the particle that has an oxide.

[0126] Also, as shown in FIG. 10B, the region 331 has an area that is not covered by the region 332. Also, the region 332 may have an area that is not covered by the region 333. For example, the region 331 may be adjacent to the region 333. 32 and area 333.

[0127] Region 332 preferably has a different composition than region 331 .

[0128] For example, the composition of region 331 and region 332 are measured separately, and region 331 contains lithium and manganese. region 332 contains lithium, manganese, element M, and oxygen; The atomic ratio of lithium, manganese, element M, and oxygen in region 331 is a1:b1: The atomic ratio of lithium, manganese, element M, and oxygen in region 332 is represented as c1:d1. The case where area 331 and area 332 are expressed as a2:b2:c2:d2 will be described. The composition of each of the 32 can be determined by, for example, EDX (energy dispersive x-ray diffraction) using a TEM (transmission electron microscope). The measurement using EDX can measure the composition of lithium. Therefore, in the following, we will focus on the difference in composition between region 331 and region 332. The following describes elements other than lithium. Here, d1 / (b1+c1) is 2.2 or more. is preferable, more preferably 2.3 or more, and even more preferably 2.35 or more and 3 or less. It is more preferable that d2 / (b2+c2) is less than 2.2. It is more preferable that the ratio is less than 1.1, and further more preferable that the ratio is 1.1 or more and 1.9 or less. Even in this case, the entire lithium manganese composite oxide particle including the regions 331 and 332 The composition preferably satisfies the above-mentioned condition 0.26≦(b+c) / d<0.5.

[0129] In addition, the manganese in region 332 has a different valence than the manganese in region 331. In addition, the element M in the region 332 may have a different valence from the element M in the region 331. The number may be any number.

[0130] More specifically, the region 331 is a lithium manganese composite having a layered rock salt type crystal structure. The region 332 is preferably a lithium oxide having a spinel type crystal structure. It is preferable that the metal oxide is a manganese-manganese composite oxide.

[0131] Here, when there is a spatial distribution in the composition of each region or the valence of an element, for example, The composition and valence of each area are evaluated, and the average value is calculated. good.

[0132] A transition layer may be provided between the region 332 and the region 331. For example, a transition layer is a region where the composition changes continuously or stepwise. A transition layer is a region where the structure changes continuously or stepwise. A region in which the constant changes continuously or stepwise. Or, the second region and the first region A mixed layer may be provided between the two layers. Here, the mixed layer is, for example, a layer having two layers with different crystal orientations. The mixed layer refers to a mixture of the above crystals. Alternatively, the mixed layer may be a layer of crystals having different crystal structures. Alternatively, a mixed layer may refer to a mixture of two or more crystals having different compositions, e.g. This refers to the case where two or more crystals are mixed together.

[0133] Region 333 can be made of carbon or a metal compound, where the metal is For example, cobalt, aluminum, nickel, iron, manganese, titanium, zinc, lithium, etc. Examples of metal compounds include oxides and fluorides of these metals. and the like.

[0134] Of the above, it is particularly preferable that the region 333 contains carbon. Carbon has high electrical conductivity. Therefore, by using carbon-coated particles in the electrodes of a power storage device, the resistance of the electrodes can be reduced, for example. In addition, the region 333 preferably includes a graphene compound. By using a graphene compound in the region 333, the particles of lithium manganese composite oxide The graphene compound will be described later. More specifically, 33 may include graphene or graphene oxide. In addition, graphene obtained by reducing graphene oxide is used as the graphene. Graphene has excellent electrical properties, such as high electrical conductivity, and high flexibility. The region 333 has excellent physical properties, such as high mechanical strength and oxidation. By using laphene to perform reduction, the region 332 adjacent to the region 333 may be oxidized. be.

[0135] The region 333 has a graphene compound, so that the lithium manganese composite oxide can be used as a positive electrode. The cycle characteristics of a secondary battery using this material can be improved.

[0136] The film thickness of the region 333 is preferably set to be not less than 0.4 nm and not more than 40 nm.

[0137] In addition, the lithium manganese composite oxide has, for example, an average particle size of the primary particles of 5 nm or more. It is preferably 50 μm or less, and more preferably 100 nm or more and 500 nm or less. In addition, the specific surface area is 5m 2 / g or more 15m 2 / g or less. The average particle size of the secondary particles is preferably 5 μm or more and 50 μm or less.

[0138] As the negative electrode active material, for example, a carbon-based material or an alloy-based material can be used.

[0139] Carbon-based materials include graphite, graphitizable carbon (soft carbon), and non-graphitizable carbon (hard carbon). Carbon nanotubes, graphene, carbon black, etc. stomach.

[0140] Examples of graphite include artificial graphite and natural graphite. Examples of artificial graphite include meso graphite. Examples include carbon microbeads (MCMB), coke-based artificial graphite, and pitch-based artificial graphite. Here, as the artificial graphite, spherical graphite having a spherical shape can be used. For example, the MCMB may have a spherical shape, which is preferred. It is relatively easy to reduce the product, which may be preferable. , flake graphite, and spherical natural graphite.

[0141] Graphite is formed when lithium ions are inserted into graphite (lithium-graphite intercalation compound is formed) It shows a low potential similar to that of lithium metal (0.1 to 0.3 V vs. Li / Li + This allows the lithium-ion secondary battery to exhibit a high operating voltage. Graphite has a relatively high capacity per unit volume, a relatively small volume expansion, and is inexpensive. It is preferable because it has advantages such as higher safety compared to lithium metal.

[0142] As a negative electrode active material, it can carry out charge and discharge reactions by alloying and dealloying reactions with lithium. Any possible element can be used, for example silicon, tin, gallium, aluminum, Germanium, lead, antimony, bismuth, silver, zinc, cadmium, indium, etc. Materials containing at least one of these elements can be used. These elements have a low capacity compared to carbon. Silicon has a high theoretical capacity of 4200mAh / g. It is preferable to use silicon, and compounds containing these elements may also be used. For example, SiO, Mg2Si, Mg2Ge, SnO, SnO2, Mg2Sn, SnS2, V2Sn3, FeSn2, CoSn2, Ni3Sn2, Cu6Sn5, Ag3Sn, Ag 3Sb, Ni2MnSb, CeSb3, LaSn3, La3Co2Sn7, CoSb3, InSb, SbSn, etc. Here, charging and discharging are performed by alloying and dealloying reactions with lithium. Elements capable of undergoing a reaction and compounds containing such elements are sometimes called alloy materials. be.

[0143] In this specification and the like, SiO refers to, for example, silicon monoxide. Alternatively, SiO refers to, It can also be expressed as SiOx, where x preferably has a value close to 1. For example, x is preferably 0.2 or more and 1.5 or less, and more preferably 0.3 or more and 1.2 or less.

[0144] 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.

[0145] 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.

[0146] 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.

[0147] 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 form an alloy with the metal may be used as the negative electrode active material. Further materials that cause this include Fe2O3, CuO, Cu2O, RuO2, and Cr2O3. Oxides such as CoS 0.89 , NiS, CuS and other sulfides, Zn3N2, Cu3N, Ge Nitrides such as 3N4, phosphides such as NiP2, FeP2, CoP3, FeF3, BiF3, etc. This also occurs with fluoride.

[0148] The negative electrode active material is preferably such that the lower the reaction potential is, the higher the voltage of the power storage device can be increased. On the other hand, when the potential is low, the power to reduce the electrolyte is also strong. The range of potentials within which the electrolyte does not decompose is called the potential window. The negative electrode is essentially a potential window where the electrode potential is equal to that of the electrolyte. It is necessary to be within the potential window, but for example, lithium ion secondary batteries and lithium ion capacitors The potential of most of the active materials used in the negative electrodes of batteries exceeds the potential window of almost all electrolytes. In particular, materials with low reaction potential such as graphite and silicon have the advantage of being able to increase the voltage of the storage device. However, there is a problem in that the electrolyte is more susceptible to reductive decomposition.

[0149] In addition, carrier ions such as lithium are absorbed in the negative electrode active material in advance. Good too.

[0150] The electrodes 101 and 151 may also contain a conductive additive. For example, a carbon material, a metal material, or a conductive ceramic material can be used. A fibrous material may be used as the conductive assistant. The content of the conductive assistant relative to the total amount of the active material layer is preferably 1 wt% or more and 10 wt% or less, and more preferably 1 wt% or more and 5 wt% or less. .

[0151] The conductive additive can form an electrically conductive network in the electrode. This allows the positive electrode active material layer to maintain an electrical conduction path between the positive electrode active materials. By adding an auxiliary, an active material layer having high electrical conductivity can be realized.

[0152] Examples of the conductive assistant include natural graphite, artificial graphite such as mesocarbon microbeads, carbon Examples of carbon fibers include mesophase pitch carbon fibers. Carbon fibers such as isotropic pitch-based carbon fibers can be used. Carbon nanofibers, carbon nanotubes, etc. can be used. The nanotubes can be produced, for example, by a vapor phase growth method. For example, carbon black (acetylene black (AB) etc.), graphite particles Carbon materials such as graphene and fullerene can be used. Metal powders and fibers such as nickel, aluminum, silver, and gold, as well as conductive ceramic materials, etc. can be used.

[0153] In addition, a graphene compound may be used as the conductive assistant.

[0154] Graphene compounds have excellent electrical properties, including high electrical conductivity, as well as high flexibility and In addition, the graphene may have excellent physical properties such as high mechanical strength. Graphene compounds have a planar shape. Graphene compounds enable surface contact with low contact resistance. In addition, even if the material is thin, it can have very high conductivity, and a small amount can be used efficiently in the active material layer. A conductive path can be formed. Therefore, graphene compounds are used as conductive additives. This is preferable because it is possible to increase the contact area between the active material and the conductive assistant. In addition, it is preferable because it may be possible to reduce electrical resistance. For example, it is particularly preferred to use graphene or multi-graphene or RGO.

[0155] When using an active material with a small average particle size, for example, 1 μm or less, use the active material ratio table The area is large, and more conductive paths connecting the active materials are required. In such cases, The graphene compound can efficiently form a conductive path even in a small amount. , is particularly preferred.

[0156] As an example, the following describes a case where a graphene compound is used as a conductive additive in the layer 102. An example of the surface configuration will be described.

[0157] FIG. 11A shows a vertical cross-sectional view of the layer 102. The layer 102 is made of a granular active material 103 and a conductive material. The graphene compound 321 is an electrochemical assistant, and the binder 104 is included. For example, graphene or multi-graphene may be used as the graphene compound 321. Preferably, the graphene compound 321 has a sheet shape. Compound 321 is a compound having a plurality of multi-graphenes or / and a plurality of graphenes in part. The sheet may be in the form of overlapping sheets. An enlarged view of the affected area is shown.

[0158] In the longitudinal section of the layer 102, as shown in FIG. 11(A), the inside of the layer 102 is generally The sheet-like graphene compound 321 is dispersed almost uniformly. The phenylene compound 321 is shown in bold in schematic form, but in reality it is a single or multiple layer structure of carbon molecules. The plurality of graphene compounds 321 are a thin film having a plurality of granular active materials 103. The active material 103 is wrapped, covered, or stuck to the surface of the active material 103. Since the electrodes are formed in the same shape, they are in surface contact with each other.

[0159] Here, a plurality of graphene compounds are bonded to each other to form a mesh-like graphene compound. The graphene compound is then bonded to a graphene sheet (hereinafter referred to as a graphene compound net or a graphene net). When the active material is covered with a graphene net, the graphene net can Therefore, the amount of binder can be reduced. Since it is possible to use or not use the active material in the electrode volume and weight, The ratio of the power storage capacity to the power consumption can be improved. In other words, the capacity of the power storage device can be increased. do.

[0160] Here, graphene oxide is used as the graphene compound 321 and is mixed with an active material to form a layer 1. It is preferable to form a layer of the graphene compound 321 and then reduce the layer. By using graphene oxide, which has extremely high dispersibility in aqueous solvents, The acid 321 can be dispersed almost uniformly in the layer 102. In order to reduce graphene oxide by volatilizing and removing the solvent from the dispersion medium containing the graphene oxide, The graphene compound 321 remaining in the layer 102 partially overlaps with each other and is in surface contact with each other. By dispersing the oxides at a high degree, a three-dimensional conductive path can be formed. The reduction of the phene may be carried out, for example, by heat treatment or by using a reducing agent.

[0161] Therefore, unlike granular conductive additives such as acetylene black, which come into point contact with the active material, Since the phenyl compound 321 enables surface contact with low contact resistance, it is not a conventional conductive additive. Improves electrical conductivity between the granular active material 103 and the graphene compound 321 with a smaller amount than that of Therefore, the ratio of the active material 103 in the layer 102 can be increased. This makes it possible to increase the discharge capacity of the power storage device.

[0162] The electrode 101 and the electrode 151 may have a binder. Styrene-butadiene rubber (SBR), styrene-isoprene-styrene rubber, acrylonitrile tolyl-butadiene rubber, butadiene rubber, ethylene-propylene-diene copolymer, etc. It is preferable to use a rubber material such as fluororubber as a binder. do.

[0163] As the binder, it is preferable to use, for example, a water-soluble polymer. As the molecule, for example, polysaccharides can be used. CMC, methyl cellulose, ethyl cellulose, hydroxypropyl cellulose Cellulose derivatives such as cellulose, diacetyl cellulose, regenerated cellulose, and starch These water-soluble polymers can be used in combination with the above-mentioned rubber materials. It is even better if there is a

[0164] Alternatively, the binder may be polystyrene, polymethyl acrylate, or polymethyl methacrylate. Polymethylmethacrylate (PMMA), Sodium polyacrylate, Polyvinyl alcohol (PVA), Poly Ethylene oxide (PEO), polypropylene oxide, polyimide, polyvinyl chloride, Polytetrafluoroethylene, polyethylene, polypropylene, isobutylene, polyethylene Polyethylene terephthalate, nylon, polyvinylidene fluoride (PVdF), polyacrylonitrile Polyvinyl (PAN), Polyvinyl chloride, Ethylene propylene diene polymer, Polyacetic acid It is preferable to use materials such as vinyl and nitrocellulose.

[0165] The binder may be used in combination of two or more of the above.

[0166] For example, a material having a particularly excellent viscosity adjusting effect may be used in combination with another material. For example, rubber materials have excellent adhesive strength and elasticity, but it is difficult to adjust the viscosity when mixed with a solvent. In such cases, for example, it is possible to mix the material with a particularly excellent viscosity adjusting effect. As a material having a particularly excellent viscosity adjusting effect, for example, a water-soluble polymer is preferably used. In addition, examples of water-soluble polymers that are particularly effective in adjusting viscosity include the above-mentioned polysaccharides, such as cellulose, polysaccharides, and polysaccharides such as cellulose. Carboxymethylcellulose (CMC), methylcellulose, ethylcellulose, hydroxy Cellulose derivatives such as dipropyl cellulose, diacetyl cellulose, and regenerated cellulose Conductive materials and starch can be used.

[0167] In addition, cellulose derivatives such as carboxymethyl cellulose are, for example, The solubility of cellulose is increased by converting it into a salt such as sodium salt or ammonium salt. The higher the solubility, the easier it becomes to exert the effect of a viscosity adjuster. It is also possible to improve the dispersibility of the active material and other components when preparing a battery. In this study, the cellulose and cellulose derivatives used as binders for electrodes include and salts thereof.

[0168] Water-soluble polymers stabilize viscosity by dissolving in water, and also serve as active materials and binders. Other materials to be combined, such as styrene butadiene rubber, are stable in aqueous solution. In addition, since it has a functional group, it is easy to stably adsorb on the surface of the active material. It is expected that cellulose derivatives such as carboxymethyl cellulose, for example, For example, many materials have functional groups such as hydroxyl groups and carboxyl groups, and because of these functional groups, It is expected that the molecules will interact with each other and widely cover the surface of the active material.

[0169] When the binder that covers or contacts the surface of the active material forms a film, it is called a passive film. It is expected that the passive film will act as a barrier to prevent the decomposition of the electrolyte. , a film with no electronic conductivity or a film with extremely low electrical conductivity, e.g., the surface of an active material When a passive film is formed on the electrolyte, the decomposition of the electrolyte can be suppressed at the battery reaction potential. In addition, the passive film suppresses electrical conductivity and does not allow lithium ions to be conducted. It would be even better if this could be achieved.

[0170] <How to make electrodes> An example of a method for producing an electrode is shown below. First, a conductor 201 is prepared. Here, a sheet The conductive material 201 is formed in a rectangular shape. The conductive material 201 is manufactured by referring to the above embodiment. do.

[0171] Next, the active material 103 and a solvent are mixed to prepare a first mixture. Alternatively, a binder may be added and mixed. A polar solvent may be used as the solvent. For example, For example, water, methanol, ethanol, acetone, tetrahydrofuran (THF), dimethyl Dimethylformamide (DMF), N-methylpyrrolidone (NMP) and dimethylsulfoxide (DMSO) or a mixture of two or more of the first material and When a rubber material is used as the first material and a water-soluble polymer is used as the second material, water is used as the solvent. It is preferable.

[0172] Next, the prepared first mixture is applied onto the conductor 201. After that, the first mixture is heated or otherwise treated. The solvent in the first mixture is then evaporated to form layer 102 .

[0173] (Embodiment 3) In this embodiment, a power storage device of one embodiment of the present invention will be described.

[0174] As an example of a power storage device of one embodiment of the present invention, a lithium-ion battery or the like that uses an electrochemical reaction secondary batteries, electric double layer capacitors, redox capacitors and other electrochemical capacitors, Examples of the battery include a gas battery and a fuel cell.

[0175] <Wound-type storage battery> As an example of the power storage device, a wound type storage battery will be described. FIG. 12 shows a wound type storage battery. Here is an example.

[0176] The power storage device 980 shown in FIG. 12 includes a wound body 993 and an outer casing 983. The battery 993 includes an electrode 101, an electrode 151, and a separator 996. An electrolyte is poured into the inside of the capacitor 983. The power storage device 980 is connected to the conductor 201. It is preferable that the electrode 151 has a lead electrode 997 connected to the lead electrode 997 and a lead electrode 998 connected to the electrode 151. For the electrodes 101 and 151, the above-described embodiments can be referred to.

[0177] Here, the electrode 101 is an electrode in which a layer 102 is formed on a strip-shaped conductor 201. In this example, the layer 102 is a lithium manganese composite oxide (LiMnO2) as an active material. Here is an example of having an object.

[0178] Here, the area of ​​the conductor 201 is, for example, 1 mm 2 More than 100m 2 Below, 25mm 2 1 more 0m 2 Below, 100mm 2 More than 3m 2 The following is acceptable.

[0179] In this example, the electrode 101 is an electrode in which a layer 102 is formed on a strip-shaped conductor 201. In the above, an example in which the layer 102 is not provided has been described, but the power storage device shown in FIG. 980 may be applied.

[0180] First, the electrode 101 and the electrode 151 are prepared. Here, the strip-shaped electrode 151 is a strip-shaped collection The active material layer may be formed on at least one surface of the electrode. As the active material, copper is used for the current collector, and graphite is used as the active material of the active material layer. As shown in FIG. 3(A), a lead electrode 997 is attached to the conductor 201 of the electrode 101, and A lead electrode 998 is joined to the current collector of 51. For example, ultrasonic Wave welding or the like may be used.

[0181] Next, as shown in FIG. 13B, the electrode 101, the separator 996, and the electrode 151 are stacked from the bottom. 14(A), the laminated electrodes are laminated in this order. 101, the electrode 151, and the separator 996 are wound together to produce a wound body 993. In this case, a core may be used for winding.

[0182] Next, as shown in FIG. 14(B), the wound body 993 is wrapped around the outer casing 983a and the outer casing 983b. Then, the exterior body 983a and the exterior body 983b are joined together. The assembled exterior body is called exterior body 983. The exterior body 983 is provided with a It is advisable to leave the part where 983a and the exterior body 983b are not joined. Sometimes called an inlet. The electrolyte is injected through the inlet. After that, the inlet is joined and the battery is charged. A device 980 is prepared.

[0183] Here, for example, a conductor 201 is formed on one side of a strip-shaped separator 996, and then the conductor The layer 102 may be formed on the conductor 201. That is, the conductor 201 may be formed on the separator 996. and layer 102 are laminated, and after fixing separator 996, conductor 201 and layer 102, Then, electrode 151 and separator 996 may be laminated.

[0184] When an aprotic organic solvent is used as the solvent for the electrolyte, for example, ethylene Carbonate (EC), Propylene Carbonate (PC), Butylene Carbonate, Chloro Polyethylene carbonate, vinylene carbonate, γ-butyrolactone, γ-valerolactone ton, dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl meth Ethylene glycol monocarbonate (EMC), methyl formate, methyl acetate, methyl butyrate, 1,3-dioxane , 1,4-dioxane, dimethoxyethane (DME), dimethyl sulfoxide, diethyl Ether, methyl diglyme, acetonitrile, benzonitrile, tetrahydrofuran, Sulfolane, sultone, or any combination of two or more of these. Can be used in ratios.

[0185] In addition, by using a polymer material that gels as a solvent for the electrolyte, the resistance to leakage, etc. Safety is improved. In addition, it is possible to make the secondary battery thinner and lighter. Representative examples of materials include silicone gel, acrylic gel, acrylonitrile gel, and poly Ethylene oxide gel, polypropylene oxide gel, fluorine polymer gel etc.

[0186] In addition, a flame-retardant and non-volatile ionic liquid (room-temperature molten salt) is used as the solvent for the electrolyte. By using one or more, the internal temperature of the storage device can be increased due to an internal short circuit or overcharging. Even if the battery is heated, it can prevent the battery from bursting or catching fire. The electrolyte solution is made of cations and anions. Ammonium cations, tertiary sulfonium cations, and quaternary phosphonium cations Aliphatic onium cations such as imidazolium cations and pyridinium cations The aromatic cations are also used as anions in the electrolyte. Anions, monovalent methide anions, fluorosulfonate anions, perfluoroalkyl sulfonic acid anion, tetrafluoroborate anion, perfluoroalkyl borate anion phosphate anion, hexafluorophosphate anion, or perfluoroalkyl phosphat ate anion, etc.

[0187] When lithium ions are used as the carrier, the salt used in the electrolyte is LiPF6. , LiClO4, LiAsF6, LiBF4, LiAlCl4, LiSCN, LiBr, LiI, Li2SO4, Li2B 10 Cl 10 , Li2B 12 Cl 12 , LiCF3SO 3, LiC4F9SO3, LiC(CF3SO2)3, LiC(C2F5SO2)3, L iN(CF3SO2)2, LiN(C4F9SO2)(CF3SO2), LiN(C2F 5SO2)2 or any combination of two or more of these lithium salts. and ratios can be used.

[0188] In addition, the electrolyte used in the electricity storage device is free of granular waste and elements other than the constituent elements of the electrolyte (hereinafter referred to as It is preferable to use a highly purified electrolyte solution with a low content of impurities. Specifically, impurities in the electrolyte should be 1 weight % or less, preferably 0.1 weight % or less. It is preferable to set it to eight percent or less, and more preferably to set it to 0.01 percent or less by weight.

[0189] In addition, the electrolyte contains vinylene carbonate, propane sultone (PS), and tert-butyl Addition of benzene (TBB), fluoroethylene carbonate (FEC), LiBOB, etc. The concentration of the additive may be, for example, 0.1 weight % or more relative to the total solvent. The upper limit should be 5 weight % or less.

[0190] Alternatively, a polymer gel electrolyte may be used in which a polymer is swollen with an electrolytic solution.

[0191] The polymer may be, for example, a polyalkylene oxide such as polyethylene oxide (PEO). Polymers with side structures, PVDF, polyacrylonitrile, etc., and their For example, a copolymer containing PVDF and hexafluoropropylene ( PVDF-HFP, a copolymer of PVDF and HFP, can be used. The polymer may have a porous shape.

[0192] In addition, instead of the electrolyte solution, a solid electrolyte having an inorganic material such as a sulfide or oxide is used. It is possible to use a solid electrolyte containing a polymer material such as PEO (polyethylene oxide). When a solid electrolyte is used, the installation of a separator or spacer becomes unnecessary. Since the entire battery can be made solid, there is no risk of leakage, and safety is dramatically improved.

[0193] The separator 996 may be, for example, paper, nonwoven fabric, glass fiber, ceramics, or Nylon (polyamide), Vinylon (polyvinyl alcohol fiber), polyester, a Use synthetic fibers such as acrylic, polyolefin, and polyurethane. This can be done.

[0194] The storage battery 990 shown in FIG. 15(A) has an exterior body 991 and an exterior body 992 having a different shape from those shown in FIG. FIG. 15B shows components of the storage battery 990. The above-mentioned wound body 993 is housed in the portion.

[0195] The exterior body 983, the exterior body 991, and the exterior body 992 are made of a metal material such as aluminum. Resin materials can be used. If a resin material is used as the material for the exterior body, it is possible to prevent external forces from being applied. The exterior body can be deformed when a load is applied, and a flexible storage battery can be produced. The exterior can be made of polyethylene, polypropylene, polycarbonate, ion Aluminum, stainless steel, copper, nickel, etc. are applied to the membrane made of materials such as mercaptan and polyamide. A thin metal film having excellent flexibility such as a polyamide is further provided on the thin metal film as the outer surface of the exterior body. The film has a three-layer structure with an insulating synthetic resin film such as acrylic resin, polyester resin, etc. It is possible.

[0196] For example, when the electrode 101 is used as a positive electrode, the electrode 151 may be used as a negative electrode. When the electrode 101 is used as a negative electrode, the electrode 151 is used as a positive electrode.

[0197] Specifically, for example, an electrode 101 is used as a positive electrode, and the active material 103 of the electrode 101 is The positive electrode active material shown in the second embodiment is used as the active material 103. For example, Li a Mn b M c O d A lithium manganese composite oxide represented by the following formula is used. Electrode 151 is used as the negative electrode. The electrode 151 includes the negative electrode active material described in Embodiment 2.

[0198] Examples of various forms of storage batteries are shown below. In the storage batteries shown below, The description of the electrode 101 and the electrode 151 can be referred to. For example, the positive electrode shown in FIG. 13 as negative electrode 506, and the description of electrode 151 in FIG. Please refer to the description regarding this.

[0199] As another example of a wound type storage battery, a cylindrical storage battery is shown in FIG. As shown in FIG. 16(A), the battery 600 has a positive electrode cap (battery lid) 601 on the upper surface. The battery can (outer can) 602 is provided on the side and bottom. It is insulated from the outer can 602 by a gasket (insulating packing) 610.

[0200] FIG. 16(B) is a schematic diagram showing a cross section of a cylindrical storage battery. Inside the can 602, a strip-shaped positive electrode 604 and a negative electrode 606 are sandwiched between a separator 605. A wound battery element is provided. Although not shown, the battery element is wound around a center pin. The battery can 602 is closed at one end and open at the other end. The material is nickel, aluminum, titanium, or other metals that are resistant to corrosion by the electrolyte. These and their alloys with other metals (e.g., stainless steel, etc.) can be used. In addition, in order to prevent corrosion by the electrolyte, it is preferable to coat the electrode with nickel, aluminum, or the like. A battery element in which a positive electrode, a negative electrode, and a separator are wound inside a battery can 602. The battery element is sandwiched between a pair of opposing insulating plates 608 and 609. A non-aqueous electrolyte (not shown) is poured into the battery can 602. A coin-type storage battery or the like can be used.

[0201] The positive and negative electrodes used in cylindrical storage batteries are wound, so active material is formed on both sides of the current collector. A positive electrode terminal (positive electrode current collecting lead) 603 is connected to the positive electrode 604, and a negative A negative electrode terminal (negative electrode current collecting lead) 607 is connected to the positive electrode 606. The positive terminal 607 may be made of a metal material such as aluminum. 03 is resistance welded to the safety valve mechanism 612, and the negative terminal 607 is resistance welded to the bottom of the battery can 602. The safety valve mechanism 612 is a PTC (Positive Temperature Coefficient) The positive electrode cap 601 is electrically connected to the positive electrode cap 601 via a capacitance 611. The safety valve mechanism 612 is a mechanism for releasing the positive electrode cap 601 when the internal pressure of the battery increases beyond a predetermined threshold. The PTC element 611 cuts off the electrical connection between the positive electrode 604 and the positive electrode 604. It is a thermal resistor element whose resistance increases when the temperature rises, and the amount of current is limited by the increase in resistance. It prevents abnormal heat generation. The PTC element is made of barium titanate (BaTiO3) Semiconductor ceramics and the like can be used.

[0202] When winding electrodes in a cylindrical storage battery as shown in Figure 16, large amounts of In addition, when the electrode winding body is housed in a housing, the electrode always has a winding shaft. Even if a large stress acts on the electrode, the active material This can prevent the material from cleaving.

[0203] <Thin storage battery> As an example of a power storage device, a thin storage battery is shown in FIG. 17. The thin storage battery has flexibility. If the structure is such that the flexible portion is at least partially mounted on an electronic device, the flexible portion can be electrically The battery can also be bent to match the deformation of the secondary device.

[0204] FIG. 17 shows an external view of a thin storage battery 500. Also, FIGS. 18(A) and 18(B) show 17 shows a cross section taken along the line A1-A2 and a cross section taken along the line B1-B2 shown by dashed lines in FIG. 500 is a positive electrode 503 having a positive electrode current collector 501 and a positive electrode active material layer 502, and a negative electrode current collector A negative electrode 506 having a negative electrode active material layer 505 and a separator 507, and an electrolyte The battery has a positive electrode 503 and a negative electrode 508 provided in the exterior body 509. A separator 507 is provided between the battery and the battery 506. The inside of the exterior body 509 contains an electrolyte 50 It is filled with 8.

[0205] The separator 507 is processed into a bag shape and encases either the positive electrode 503 or the negative electrode 506. For example, as shown in FIG. 19(A), the positive electrode 503 is sandwiched between the electrodes. The separator 507 is folded in half so that the sealing portion 5 is located outside the area where the separator 507 overlaps with the positive electrode 503. By sealing with the separator 507, the positive electrode 503 can be reliably supported within the separator 507. Then, as shown in FIG. 19(B), the positive electrode 503 and the negative electrode 504 wrapped in the separator 507 are The electrodes 506 are alternately stacked and disposed in an exterior body 509 to form a thin storage battery 50 It is a good idea to form 0.

[0206] In addition, in FIG. 17, the positive electrode lead electrode 510 and the negative electrode lead electrode 511 are arranged on the same side. However, as shown in FIG. 20, the positive electrode lead electrode 510 and the negative electrode lead electrode 511 are connected to different sides. In this way, the storage battery according to one embodiment of the present invention allows the lead electrodes to be freely arranged. Therefore, the degree of design freedom is high. In addition, the manufacturing method of a product using the storage battery according to one embodiment of the present invention can be improved. It can improve sexuality.

[0207] The material and structure of exterior body 509 can be referred to for exterior body 983, etc.

[0208] In FIG. 18, as an example, the number of pairs of facing positive electrode active material layers and negative electrode active material layers is set to five. However, the number of electrode active material layers is not limited to five, and may be more or less. When the number of electrode active material layers is large, a storage battery having a larger capacity can be obtained. In addition, when the number of electrode active material layers is small, the battery can be made thin and has excellent flexibility. It is possible.

[0209] For example, the positive electrode 503 shown in FIG. 17 is a conductor 201 and a layer 102 on the conductor 201. 18, the case where the layer 102 has a positive electrode active material is considered. In this case, the area of ​​the conductor 201 of the positive electrode 503 is, for example, 1mm 2 More than 1m 2 Below, 25mm 2 More than 1m 2 Below, 100mm 2 More than 0.1m 2 Below As long as it's below, that's fine.

[0210] Next, various examples of lamination of the positive electrode, the negative electrode and the separator are shown.

[0211] FIG. 21A shows an example in which six layers of positive electrodes 111 and six layers of negative electrodes 115 are stacked. A positive electrode active material layer 122 is provided on one surface of a positive electrode current collector 121 of the electrode 111. The negative electrode 115 has a negative electrode current collector 125 on one surface of which a negative electrode active material layer 126 is provided.

[0212] In the configuration shown in FIG. 21(A), the positive electrode 111 does not have a positive electrode active material layer 122. The positive electrode 115 is placed on the positive electrode 11 so that the surfaces of the negative electrode 115 that do not have the negative electrode active material layer 126 are in contact with each other. 1 and the negative electrode 115 are laminated in this order. The surfaces of the negative electrodes 115 that do not have the negative electrode active material layer 122 are called the surfaces of the negative electrodes 115 that do not have the negative electrode active material layer 126. The contact surface between the metals can be created by the active material and the separator. The coefficient of friction can be reduced compared to the contact surface of the other surface.

[0213] Therefore, when the secondary battery 10 is curved, the positive electrode 111 does not have the positive electrode active material layer 122. The surfaces of the negative electrodes 115 that do not have the negative electrode active material layer 126 slide against each other, so that the inner diameter of the curve and The stress caused by the difference in the outer diameter can be released. When the storage battery 500 is curved, the exterior body 509 of the thin storage battery 500 has a curved portion. This refers to the radius of curvature of the surface located on the inside of the thin storage battery 500. In addition, the storage battery 500 can be made thin and highly reliable.

[0214] FIG. 21(B) shows an example of lamination of a positive electrode 111 and a negative electrode 115 different from that shown in FIG. 21(A). In the configuration shown in FIG. 21(B), a positive electrode active material layer 122 is provided on both sides of a positive electrode current collector 121. As shown in FIG. 21(B), the positive electrode current collector By providing the positive electrode active material layer 122 on both sides of the positive electrode active material layer 121, This allows for a larger capacity.

[0215] FIG. 21C shows an example of lamination of a positive electrode 111 and a negative electrode 115 different from that shown in FIG. 21B. In the configuration shown in FIG. 13(C), a negative electrode active material layer 126 is provided on both sides of a negative electrode current collector 125. As shown in FIG. 13(C), the negative electrode current collector By providing the negative electrode active material layer 126 on both sides of the negative electrode active material layer 125, The capacity can be further increased.

[0216] In the configuration shown in FIG. 21 and FIG. 22, the separator 123 encloses the positive electrode 111 in a bag shape. However, the present invention is not limited to this. 22(A) shows an example having a separator 123 having a different structure from that shown in FIG. Then, a sheet-like separator 123 is placed between the positive electrode active material layer 122 and the negative electrode active material layer 126. The difference from the configuration shown in FIG. 21(A) is that one sheet is provided. In the configuration, six layers of positive electrodes 111 and six layers of negative electrodes 115 are laminated, and six layers of separators 123 are laminated. It has been established.

[0217] FIG. 22(B) shows an example in which a separator 123 different from that in FIG. 22(A) is provided. In the configuration shown in FIG. 22(B), one separator 123 is provided between the positive electrode active material layer 122 and the negative electrode active material layer 123. The point where the layer 126 is folded back multiple times so as to be sandwiched between the layers 126 is shown in FIG. The structure shown in FIG. 22(B) is different from the structure shown in FIG. 22(A). It can also be said that the layer is connected by extending the connector 123. In the configuration, six layers of positive electrodes 111 and six layers of negative electrodes 115 are laminated, and a small number of separators 123 are used. The separator 123 is folded at least five times. The active material layer 126 is not only sandwiched between the positive electrodes 111 and the negative electrodes 112 but is also extended to form a The poles 115 may be tied together.

[0218] Alternatively, the positive electrode, the negative electrode and the separator may be laminated as shown in FIG. FIG. 23(A) is a cross-sectional view of the first electrode assembly 130, and FIG. 23(B) is a cross-sectional view of the second electrode assembly 131. 23(C) is a cross-sectional view taken along dashed line A1-A2 in FIG. 1(A). In order to clarify the drawing, in Fig. 3C, the first electrode assembly 130, the electrode assembly 131 and the separator An excerpt from data 123 is shown below.

[0219] As shown in FIG. 23C, the thin storage battery 500 includes a plurality of first electrode assemblies 130 and and a plurality of electrode assemblies 131.

[0220] As shown in FIG. 23(A), in the first electrode assembly 130, the positive electrode current collector 121 has a A positive electrode 111a having a positive electrode active material layer 122, a separator 123, and both sides of a negative electrode current collector 125 The negative electrode 115a having the negative electrode active material layer 126 on both sides of the separator 123 and the positive electrode current collector 121 The positive electrode 111a having the positive electrode active material layer 122 on its surface is laminated in this order. As shown in FIG. 1B, in the second electrode assembly 131, a negative electrode active material is provided on both sides of the negative electrode current collector 125. A layer 126 is formed on both sides of the negative electrode 115a, the separator 123, and the positive electrode current collector 121. A positive electrode 111a having a porous layer 122, a separator 123, and a negative electrode current collector 125 are provided on both sides thereof. A negative electrode 115a having a material layer 126 is laminated in this order.

[0221] Further, as shown in FIG. 23(C), a plurality of first electrode assemblies 130 and a plurality of electrode sets The solid body 131 is covered with a rolled separator 123 .

[0222] <Coin-type battery> An example of a coin-type storage battery will be described with reference to FIG. 24. FIG. 24(A) shows a coin FIG. 24(B) is a cross-sectional view of a coin-type (single-layer flat type) storage battery. In this type of storage battery, a positive electrode can and a negative electrode can are used as the exterior body.

[0223] The coin-type storage battery 300 has a positive electrode can 301 that also serves as a positive electrode terminal and a negative electrode can 302 that also serves as a negative electrode terminal. 302 is insulated and sealed by a gasket 303 made of polypropylene or the like. The positive electrode 304 is composed of a positive electrode current collector 305 and a positive electrode active material layer 306 provided in contact with the positive electrode current collector 305. It is formed by:

[0224] The negative electrode 307 is made up of a negative electrode current collector 308 and a negative electrode active material It is formed by layer 309 .

[0225] 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.

[0226] The positive electrode can 301 and the negative electrode can 302 are made of nickel or aluminum, which are resistant to corrosion by the electrolyte. Metals such as 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 for covering the positive electrode 304, and the negative electrode can 302 is for covering the negative electrode 305. 07 and electrically connect them to each other.

[0227] The negative electrode 307, the positive electrode 304, and the separator 310 are impregnated with an electrolyte, and the negative electrode 307, the positive electrode 304, and the separator 310 are then placed in a vacuum chamber as shown in FIG. 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.

[0228] <Curvature of exterior body> The exterior body of the electricity storage device has a minimum radius of curvature of, for example, 3 mm or more and 30 mm or less, more preferably The outer casing of the power storage device can be deformed to a value between 3 mm and 10 mm. The film is made up of one or two sheets, and the cross-sectional structure of the curved battery is The structure is sandwiched between two curves of a film.

[0229] The radius of curvature of a surface will be described with reference to FIG. 25. In FIG. 25(A), a curved surface 170 A part of a curve 1702 included in a surface 1700 is cut into a plane 1701 that cuts through 0. Approximate the arc and set the radius of the circle as the radius of curvature 1703 and the center of the circle as the center of curvature 1704. FIG. 25(B) shows a top view of the curved surface 1700. FIG. 25(C) shows the curved surface 1700 on a flat surface 1701. The cross-sectional view of 1700 is shown. When cutting a curved surface with a plane, the angle of the plane to the curved surface is The radius of curvature of the curve that appears in the cross section will differ depending on the cutting position and the cutting angle. The smallest radius of curvature is taken as the radius of curvature of the surface.

[0230] The battery device is curved and sandwiches electrodes, electrolyte, etc., 1805 between two sheets of film as the exterior body. In this case, the radius of curvature 1802 of the film 1801 on the side closer to the center of curvature 1800 of the storage device is smaller than the radius of curvature 1804 of the film 1803 on the side farther from the center of curvature 1800 ( FIG. 26(A). When the power storage device is curved to have an arc-shaped cross section, the center of curvature 1800 is close to the center of curvature 1800. The surface of the film is subjected to compressive stress, and the surface of the film far from the center of curvature 1800 is subjected to tension stress. Tensile stress is applied (Figure 26(B)). The pattern formed on the surface of the exterior body is a concave or convex pattern. When this is formed, even if compressive or tensile stress is applied, the effects of strain are not observed. Therefore, the electric storage device can be prevented from being damaged by the external casing on the side closer to the center of curvature. The minimum radius of curvature is, for example, 3 mm or more and 30 mm or less, more preferably 3 mm or more and 10 mm or less. It can be modified so that it is less than m.

[0231] The cross-sectional shape of the electricity storage device is not limited to a simple arc shape, and may be a shape that includes a partial arc. For example, the shape shown in FIG. 26(C), a wavy shape (FIG. 26(D)), an S-shape, etc. When the radius of curvature changes due to the application of an external force to the storage device, The radius of curvature may be in the range of, for example, 3 mm to 30 mm. In the most curved state, i.e., the state where the radius of curvature is smallest, the radius of curvature is preferably The thickness is preferably 3 mm or more and 10 mm or less, and more preferably 3 mm or more and 6 mm or less. When the curved surface of the power storage device has a shape having a plurality of centers of curvature, the radius of curvature of the device is set to a plurality of Among the radii of curvature at the centers of curvature, the surface with the smallest radius of curvature is the surface with two It is sufficient to use the smallest radius of curvature of the exterior body that is closer to the center of curvature of the exterior body.

[0232] <Curvature of conductor> Moreover, the conductor of one embodiment of the present invention has a sheet-like shape and a minimum radius of curvature of, for example, The deformation is from 3 mm to 30 mm, and more preferably from 3 mm to 10 mm. Therefore, the conductor of one embodiment of the present invention is free from cracks and the like caused by winding or bending. Therefore, the conductor of one embodiment of the present invention is suitable for a wound power storage device. The device can be deformed as the device is deformed by an external force. By using a conductor in a flexible power storage device, the reliability of the power storage device can be improved. can be done.

[0233] <Example of energy storage system structure> A structural example of the power storage system will be described with reference to Figs. 27 to 29. The power system refers to, for example, a device equipped with a power storage device.

[0234] 27(A) and 27(B) are diagrams showing the external appearance of the power storage system. The system includes a circuit board 900 and a storage battery 913. The storage battery 913 is provided with a label 91. 27B, the power storage system has a terminal 951 and , a terminal 952 , an antenna 914 , and an antenna 915 .

[0235] The circuit board 900 has a terminal 911 and a circuit 912. The terminal 911 is connected to the terminal 95. 1, terminal 952, antenna 914, antenna 915, and circuit 912. A plurality of terminals 911 are provided, and each of the plurality of terminals 911 is connected to a control signal input terminal, a power supply terminal, It may also be a terminal.

[0236] The circuit 912 may be provided on the back surface of the circuit board 900. The antenna 915 is not limited to a coil shape, but may be, for example, a wire or plate shape. Planar antennas, aperture antennas, traveling wave antennas, EH antennas, magnetic field antennas, induction Alternatively, an antenna such as an electric antenna may be used. 5 may be a flat conductor. This flat conductor functions as one of the conductors for electric field coupling. In other words, one of the two conductors of the capacitor is The antenna 914 or the antenna 915 may be activated. Not only that, but it is also possible to exchange power using an electric field.

[0237] The line width of antenna 914 is preferably larger than the line width of antenna 915. This allows the amount of power received by the antenna 914 to be increased.

[0238] The storage system includes a layer 9 between the antenna 914 and the antenna 915 and the storage battery 913. The layer 916 has a function of shielding the electromagnetic field caused by the battery 913, for example. The layer 916 may be made of, for example, a magnetic material.

[0239] The structure of the power storage system is not limited to the structure shown in FIG.

[0240] For example, as shown in Figs. 28(A-1) and 28(A-2), In the storage battery 913 shown in FIG. 27(B), an antenna is provided on each of a pair of opposing surfaces. FIG. 28(A-1) is an external view seen from one side of the pair of faces. FIG. 27(A-2) is an external view seen from the other side of the pair of surfaces. 27(A) and 27(B) are the same as those in the storage system shown in FIG. The explanation of the energy storage system shown in FIG. 7(B) can be used as appropriate.

[0241] As shown in FIG. 28(A-1), a layer 916 is sandwiched between one of a pair of surfaces of a storage battery 913. As shown in FIG. 28(A-2), an antenna 914 is provided on one side of the storage battery 913, and the other side of the storage battery 913 is provided on the other side of the storage battery 913. An antenna 915 is provided on the opposite side of the layer 917. The layer 917 is, for example, a storage battery 913. The layer 917 has a function of blocking electromagnetic fields caused by the electromagnetic waves. There can be.

[0242] By adopting the above structure, the size of both antenna 914 and antenna 915 can be increased. It can be heard.

[0243] Or, as shown in FIG. 28(B-1) and FIG. 28(B-2), In the storage battery 913 shown in FIG. 27(B), a separate antenna is attached to each of a pair of opposing faces. FIG. 28(B-1) is an external view of the pair of surfaces as viewed from one side, FIG. 28(B-2) is an external view seen from the other side of the pair of faces. The same parts as those in the storage system shown in FIG. 27(A) and FIG. 27(B) are shown in FIG. The description of the power storage system shown in Figure 27(B) can be used as appropriate.

[0244] As shown in FIG. 28(B-1), a layer 916 is sandwiched between one of a pair of surfaces of a storage battery 913. An antenna 914 and an antenna 915 are provided, and as shown in FIG. An antenna 918 is provided on the other of the pair of surfaces of the antenna 913 with a layer 917 sandwiched therebetween. The antenna 91 has a function of performing data communication with an external device, for example. 8, for example, an antenna having a shape applicable to antenna 914 and antenna 915 is applied. As a communication method between the power storage system and other devices via the antenna 918, The system applies a response method such as NFC that can be used between the energy storage system and other devices. It is possible.

[0245] Alternatively, as shown in FIG. 29(A), the storage battery 91 shown in FIG. 27(A) and FIG. 27(B) may be used. A display device 920 may be provided on the input side of the input terminal 911 via a terminal 919. The label 910 is electrically connected to the display device 920. It is not necessary to use the same parts as those in the power storage system shown in FIG. 27(A) and FIG. 27(B). For this purpose, the description of the power storage system shown in FIG. 27(A) and FIG. 27(B) can be used as appropriate.

[0246] The display device 920 displays, for example, an image indicating whether charging is in progress, an image indicating the amount of stored power, etc. The display device 920 may be, for example, an electronic paper, a liquid crystal display device, an electronic For example, electroluminescence (EL) display devices can be used. By using the polarizer, the power consumption of the display device 920 can be reduced.

[0247] Or, as shown in FIG. 29(B), the storage battery 91 shown in FIG. 27(A) and FIG. 27(B) A sensor 921 may be provided on the terminal 911 via a terminal 922. Note that the same parts as the power storage system shown in FIG. 27(A) and FIG. 27(B) are used. For this part, the explanation of the power storage system shown in FIG. 27(A) and FIG. 27(B) can be used as appropriate. Cut.

[0248] The sensor 921 may be, for example, a sensor for detecting force, displacement, position, velocity, acceleration, angular velocity, rotation speed, distance, etc. Distance, light, liquid, magnetic, temperature, chemicals, sound, time, hardness, electric field, current, voltage, power, radiation Use devices that include the function of measuring line, flow rate, humidity, gradient, vibration, odor, or infrared rays. By providing the sensor 921, for example, Data indicative of the temperature can be detected and stored in the memory of the circuit 912. .

[0249] The battery and the power storage system described in this embodiment include an electrode according to one embodiment of the present invention. This allows the capacity of storage batteries and power storage systems to be increased. It is possible to increase the energy density. It is also possible to improve reliability. It is also possible to extend the life. It can be made easier.

[0250] This embodiment mode can be implemented in appropriate combination with other embodiment modes.

[0251] (Embodiment 4) In this embodiment, an example in which a flexible power storage device is mounted on an electronic device will be described. .

[0252] FIG. 30 illustrates an example in which the flexible power storage device described in Embodiment 2 is mounted in an electronic device. As an example of an electronic device to which a flexible power storage device is applied, a television Equipment (also called television or television receiver), monitors for computers, digital digital cameras, digital video cameras, digital photo frames, mobile phones (mobile phones, Mobile phone devices, portable game machines, portable information terminals, audio playback devices, pachinko machines, etc. Examples include large gaming consoles.

[0253] In addition, the flexible energy storage device can be attached to the inner or outer walls of a house or building, or to an automobile. It can also be incorporated into curved interior or exterior surfaces of a vehicle.

[0254] FIG. 30A shows an example of a mobile phone. A mobile phone 7400 includes a housing 740. In addition to the display unit 7402 incorporated in the 1, the operation buttons 7403, the external connection port 7404, The mobile phone 7400 includes a speaker 7405, a microphone 7406, and the like. The device has an electrical device 7407.

[0255] FIG. 30B shows the mobile phone 7400 in a curved state. When the 00 is deformed by an external force and curved, the storage battery installed inside The storage device 7407 is also bent. At this time, the bent state of the storage device 7407 is shown in FIG. The power storage device 7407 is a thin storage battery. The power storage device 7407 is fixed in a resistor connected electrically to the current collector 7409. For example, the current collector 7409 is made of copper foil, some of which is made of gallium. The adhesion between the current collector 7409 and the active material layer in contact therewith is improved by alloying the current collector 7409 and the active material layer in contact therewith. This structure is highly reliable even when the cable is bent.

[0256] FIG. 30D shows an example of a bangle-type display device. The portable display device 7100 is 7101, a display unit 7102, operation buttons 7103, and a power storage device 7104. FIG. 30E shows the bent state of the power storage device 7104. When the device is bent and worn on the user's arm, the housing may deform and cause a part of the power storage device 7104 or The total curvature changes. The degree of curvature at any point on the curve is expressed as the radius of the corresponding circle. The value expressed as the radius of curvature is called the curvature, and the reciprocal of the radius of curvature is called the curvature. A part of the main surface of the housing or the power storage device 7104 within a range of 40 mm to 150 mm in diameter Or the entire surface of the power storage device 7104 changes. High reliability can be maintained if the deviation is within the range of 0 mm or less.

[0257] FIG. 30F shows an example of a wristwatch-type portable information terminal. Portable information terminal 7200 The housing 7201, the display unit 7202, the band 7203, the buckle 7204, the operation button 7 205, an input / output terminal 7206, etc.

[0258] The portable information terminal 7200 is capable of carrying out mobile phone calls, e-mails, viewing and creating documents, playing music, and internet connections. It can run various applications such as internet communication and computer games. Cut.

[0259] The display unit 7202 has a curved display surface, and displays information along the curved display surface. The display unit 7202 is equipped with a touch sensor, and the screen can be operated by touching it with a finger or a stylus. For example, the icon 7 displayed on the display unit 7202 can be operated by touching the By touching 207, the application can be launched.

[0260] The operation button 7205 is used to set the time, turn the power on and off, and turn wireless communication on and off. It supports various functions such as auto-start, silent mode and power saving mode. For example, an operating system built into the portable information terminal 7200 can be Depending on the system, the functions of the operation buttons 7205 can be freely set.

[0261] In addition, the mobile information terminal 7200 is capable of performing short-distance wireless communication according to a communication standard. For example, by communicating with a wireless headset, a hands-free You can also make calls.

[0262] The portable information terminal 7200 also includes an input / output terminal 7206 and is connected to other information terminals via a connector. Data can be exchanged directly through the input / output terminal 7206. The charging operation can be performed by wireless power supply without going through the input / output terminal 7206. You may go.

[0263] The display portion 7202 of the portable information terminal 7200 includes a storage device having the electrode member of one embodiment of the present invention. For example, the power storage device 7104 in FIG. It can be installed in a curved state inside or in a curved state inside the band 7203. can.

[0264] The portable information terminal 7200 preferably has a sensor. For example, a fingerprint sensor may be used as the sensor. Human body sensors such as sensors for measuring body temperature, touch sensors, pressure sensors, and acceleration sensors. It is preferable that the sensor, etc. be mounted.

[0265] FIG. 30G shows an example of a wristband-type display device. The display device 7300 has a display unit The display device 7300 includes a power storage device of one embodiment of the present invention. The display portion 7304 may be provided with a touch sensor, and may function as a portable information terminal. It is also possible.

[0266] The display surface of the display unit 7304 is curved, and the display is performed along the curved display surface. In addition, the display device 7300 can display the image by short-distance wireless communication according to a communication standard. You can change the situation.

[0267] The display device 7300 also has an input / output terminal, and can directly connect to other information terminals via a connector. It is possible to exchange data. It is also possible to charge the device via the input / output terminal. The charging operation may be performed by wireless power supply without using the input / output terminals.

[0268] This embodiment mode can be implemented in appropriate combination with other embodiment modes.

[0269] (Embodiment 5) In this embodiment, an example of an electronic device in which a power storage device can be mounted will be described.

[0270] FIG. 31(A) and FIG. 31(B) show an example of a tablet terminal that can be folded in two. The tablet terminal 9600 shown in FIG. 31(A) and FIG. 31(B) includes a housing 9630a, A housing 9630b, a movable part 9640 connecting the housings 9630a and 9630b, and a display unit 9 A display unit 9631 having a display unit 9631a and a display unit 9631b, a display mode changeover switch 96 26, power switch 9627, power saving mode switch 9625, fastener 9629 31(A) shows the tablet terminal 9600 in an open state. FIG. 31(B) shows the tablet terminal 9600 in a closed state.

[0271] The tablet terminal 9600 also includes a housing 9630a and a housing 9630b. The power storage unit 9635 is connected to the housing 9630a through the movable portion 9640. It is provided across the body 9630b.

[0272] A part of the display unit 9631a can be used as a touch panel area 9632a. By touching the operation keys 9638 displayed on the display unit 96, data can be input. In 31a, as an example, half of the area has a display function only, and the other half The display unit 96 has a touch panel function, but is not limited to this. The entire area of ​​the display unit 931a may have a touch panel function. The entire surface of 631a is made to display keyboard buttons to serve as a touch panel, and the display section 9631b is made to display It can be used as a display screen.

[0273] In addition, in the display unit 9631b, as in the display unit 9631a, The part of the touch panel can be the area 9632b of the touch panel. Touch the area where the mode display switch button 9639 is displayed with your finger or a stylus. A keyboard button can be displayed on the display portion 9631b.

[0274] In addition, the touch panel area 9632a and the touch panel area 9632b are simultaneously You can also use touch input.

[0275] A display mode changeover switch 9626 is used to change the display orientation, such as vertical or horizontal. You can choose between black and white and color display. The switch 9625 detects the usage of the light detected by the light sensor built into the tablet terminal 9600. The display brightness can be optimized according to the amount of external light at the time. In addition to optical sensors, other sensors such as gyros and acceleration sensors that detect tilt are also used. An ejection device may be built in.

[0276] FIG. 31A shows an example in which the display area of ​​the display portion 9631b is the same as that of the display portion 9631a. However, there is no particular limitation, and one size may be different from the other size. The quality of the display may also be different. For example, one display panel may provide a higher resolution display than the other. It may also be used as a rule.

[0277] FIG. 31(B) shows the tablet terminal in a closed state. The tablet terminal includes a housing 9630 and a solar cell 9 633, a charge / discharge control circuit 9634 including a DCDC converter 9636. The power storage unit according to one embodiment of the present invention is used as the power storage unit 9635.

[0278] In addition, since the tablet terminal 9600 can be folded in two, when not in use, The housing 9630b can be folded so that the housing 9630b and the housing 9630b overlap each other. Since the display units 9631a and 9631b can be protected, the tablet terminal 9600 The durability can be improved. In addition, the power storage unit 9635 using the power storage unit of one embodiment of the present invention It has flexibility and the charge / discharge capacity does not decrease easily even if it is repeatedly bent and stretched. Therefore, it has high reliability. It can provide an excellent tablet device.

[0279] In addition, the tablet terminals shown in Fig. 31(A) and Fig. 31(B) are used in various Functions that display useful information (still images, videos, text images, etc.), calendars, dates, or times A function to display the information on the display unit, and a function to input or edit the information displayed on the display unit. It has a function to input data, a function to control processing by various software (programs), etc. It is possible.

[0280] The solar cell 9633 attached to the surface of the tablet device supplies power to the touch panel. The solar cell 9633 can supply the solar cell 9633 with the following components: The battery 9635 can be efficiently charged by providing the battery on one or both sides of the housing 9630. The power storage unit 9635 may be a lithium-ion battery. This has the advantage of being compact.

[0281] The configuration and operation of the charge / discharge control circuit 9634 shown in FIG. A block diagram is shown in FIG. 31(C) and will be described. FIG. 31(C) shows a solar cell 9633, a power storage unit 96 35, DC-DC converter 9636, converter 9637, switches SW1 to SW3, The display unit 9631 is shown, along with a storage battery 9635, a DC-DC converter 9636, and a The inverter 9637 and the switches SW1 to SW3 are connected to the charge / discharge control circuit 9 This corresponds to 634.

[0282] First, an example of operation in which power is generated by the solar cell 9633 using external light will be described. The power generated by the solar cell is converted to a voltage to charge the storage battery 9635. The converter 9636 increases or decreases the voltage. When power from the battery 9633 is used, the switch SW1 is turned on, and the converter 963 7, the voltage is increased or decreased to a voltage required for the display unit 9631. When not displaying in 1, turn SW1 off and SW2 on to turn on the power storage unit 9635. It is sufficient to configure the device so as to perform charging.

[0283] The solar cell 9633 is shown as an example of a power generating means, but is not limited thereto. Storage by other power generation means such as piezoelectric elements and thermoelectric conversion elements For example, the power may be transmitted and received wirelessly (contactlessly). The configuration is a non-contact power transmission module that charges the battery by connecting the battery to the battery, or by combining it with other charging means. You may do so.

[0284] Another example of electronic equipment is shown in FIG. 32. In FIG. 32, a display device 8000 is a display device according to the present invention. 8 is an example of an electronic device including a power storage device 8004 according to one embodiment. 8000 corresponds to a display device for receiving TV broadcasts, and includes a housing 8001, a display unit 8002, a speaker, The power storage device 8004 according to one embodiment of the present invention includes: The display device 8000 is provided inside a housing 8001. The display device 8000 is supplied with power from a commercial power source. It is also possible to use the power stored in the power storage device 8004. Therefore, even when power cannot be supplied from a commercial power source due to a power outage or the like, the present invention according to one aspect of the present invention can be used. The display device 8000 can be used by using the power storage device 8004 as an uninterruptible power supply. become.

[0285] The display unit 8002 is a display device having a light emitting element such as a liquid crystal display device or an organic EL element in each pixel. Optical devices, electrophoretic displays, DMD (Digital Micromirror Devices) ice), PDP (Plasma Display Panel), FED (Field A semiconductor display device such as a 3D Emission Display can be used.

[0286] In addition, display devices are used for TV broadcast reception, personal computers, advertising displays, etc. This includes all display devices for displaying information, such as

[0287] In FIG. 32, a stationary lighting device 8100 includes a power storage device 8 according to one embodiment of the present invention. 8101 is an example of an electronic device using the lighting device 8100. The light source 8102 and the power storage device 8103 are included. In FIG. For example, the light source 101 and the light source 8102 are installed inside a ceiling 8104. 8, the power storage device 8103 may be provided inside the housing 8101. The device 8100 can receive power from a commercial power source, or can store power in a power storage device 8103. The stored power can also be used. Therefore, in the event of a power outage, the supply of power from the commercial power source is not possible. Even when power cannot be received, the power storage device 8103 of one embodiment of the present invention can be used as an uninterruptible power source. This enables the lighting device 8100 to be used.

[0288] In addition, FIG. 32 illustrates a lighting device 8100 that is installed on a ceiling 8104. However, in the power storage device of one embodiment of the present invention, in addition to the ceiling 8104, for example, the side wall 8105, the floor The present invention can be applied to a lighting device installed in a fixed position such as a desk 8106 or a window 8107. It can also be used in upper lighting devices.

[0289] In addition, the light source 8102 can be an artificial light source that artificially obtains light using electricity. Specifically, this applies to incandescent lamps, discharge lamps such as fluorescent lamps, and light-emitting diodes and organic electroluminescence (EL) elements. An example of the artificial light source is a light element.

[0290] In FIG. 32, an air conditioner having an indoor unit 8200 and an outdoor unit 8204 is 8 is an example of an electronic device including a power storage device 8203 according to one embodiment of the present invention. The indoor unit 8200 includes a housing 8201, an air outlet 8202, a power storage device 8203, and the like. In the example shown in FIG. 1, the power storage device 8203 is provided in the indoor unit 8200. The electric device 8203 may be provided in an outdoor unit 8204. The power storage device 8203 may be provided in both the outdoor units 8204. The power supply can be supplied from a commercial power source, or the power stored in the power storage device 8203 can be used. In particular, both the indoor unit 8200 and the outdoor unit 8204 are provided with a power storage device 8 If 203 is installed, when power cannot be supplied from the commercial power source due to a power outage, etc. However, by using the power storage device 8203 of one embodiment of the present invention as an uninterruptible power supply, The use of conditioners will be possible.

[0291] In addition, in Figure 32, a separate type air conditioner consisting of an indoor unit and an outdoor unit is shown. However, an integrated air conditioner that has both the indoor and outdoor functions in a single housing is also shown. The power storage device of one embodiment of the present invention can also be used for the conditioner.

[0292] In FIG. 32 , an electric refrigerator-freezer 8300 includes a power storage device 8304 according to one embodiment of the present invention. Specifically, an electric refrigerator-freezer 8300 includes a housing 8301, The door for a refrigerator 8302, the door for a freezer 8303, a power storage device 8304, and the like are included. A power storage device 8304 is provided inside a housing 8301. The power supply can be received from a commercial power source, or the power stored in the power storage device 8304 can be used. Therefore, when power cannot be supplied from commercial power sources due to a power outage, etc. Even in such a case, the power storage device 8304 of one embodiment of the present invention can be used as an uninterruptible power supply. It will be possible to use 8300 refrigerators / freezers.

[0293] Among the above-mentioned electronic devices, high-frequency heating devices such as microwave ovens and electric rice cookers The child devices require high power for a short period of time. Therefore, the power that cannot be supplied by the commercial power supply is supplemented. By using a power storage device according to one embodiment of the present invention as an auxiliary power source for supporting This can prevent the commercial power breaker from tripping when using the device.

[0294] In addition, during periods when electronic devices are not in use, the total amount of power that can be supplied by commercial power suppliers is also During periods when the ratio of the amount of electricity actually used (called the electricity usage rate) is low, By storing electricity in the electrical equipment, it is possible to prevent the power usage rate from increasing outside the above-mentioned time periods. For example, in the case of the electric refrigerator-freezer 8300, when the temperature is low, the refrigerator compartment door 83 02, during the night when the freezer door 8303 is not opened or closed, power is supplied to the power storage device 8304. Then, as the temperature rises, the refrigerator door 8302 and the freezer door 8303 open and close. During the daytime, when the electricity is consumed, the power storage device 8304 is used as an auxiliary power source. The rate can be kept low.

[0295] This embodiment mode can be implemented in appropriate combination with other embodiment modes.

[0296] (Embodiment 6) In this embodiment, an example in which a power storage device is mounted on a vehicle will be described.

[0297] In addition, by installing a power storage device in a vehicle, it can be used as a hybrid vehicle (HEV) or electric vehicle (EV). or next-generation clean energy vehicles such as plug-in hybrid vehicles (PHEVs) It can be realized.

[0298] 33A and 33B show examples of vehicles using one embodiment of the present invention. The 8400 is an electric vehicle that uses an electric motor as a power source for running. The vehicle can be powered by either an electric motor or an engine. A hybrid vehicle. By using one embodiment of the present invention, a vehicle with a long driving range can be realized. The automobile 8400 also has a power storage device. The power storage device can be an electric motor. It not only drives the 8406, but also the headlights 8401 and room lights (not shown). It is possible to supply power to the light emitting device.

[0299] In addition, the power storage device can be used to store information such as a speedometer and a tachometer of the automobile 8400. The power storage device can supply power to the navigation device of the automobile 8400. The present invention can provide power to semiconductor devices such as gating systems.

[0300] The automobile 8500 shown in FIG. 33B is a power storage device that is plugged in to the automobile 8500. It is possible to charge the battery by receiving power from an external charging facility using a contactless charging method or other methods. FIG. 33(B) shows a case where a charging device mounted on a vehicle 8500 is connected to a ground-mounted charging device 8021. The power storage device 8024 is shown being charged via a cable 8022. For charging methods and connector specifications, please refer to the specifications of CHAdeMO (registered trademark) and Combo. The charging device 8021 is a charging station installed in a commercial facility. For example, plug-in technology can be used to connect the power source to the outside. The power storage device 8024 mounted on the automobile 8500 can be charged by the power supply. Charging is performed by converting AC power to DC power via a converter such as an AC / DC converter. It is possible to do so.

[0301] Although not shown, a power receiving device is mounted on the vehicle and receives power from a ground power transmitting device in a non-contact manner. In this case, the power transmission device is installed on the road or on the exterior wall. By incorporating this, charging can be done not only when the vehicle is stopped but also while the vehicle is moving. In addition, the vehicle exterior may be provided with a power supply. A solar cell may be provided in the vehicle so that the power storage device can be charged when the vehicle is stopped or traveling. To supply power in the above, an electromagnetic induction method or a magnetic resonance method can be used.

[0302] According to one embodiment of the present invention, the cycle characteristics of a power storage device can be improved, and the reliability can be improved. Furthermore, according to one embodiment of the present invention, the characteristics of the power storage device can be improved, Therefore, the power storage device itself can be made smaller and lighter. This contributes to reducing the weight of the vehicle, which can improve the cruising distance. The on-board power storage device can also be used as a power supply source for something other than the vehicle. This allows avoiding the use of commercial power during peak hours.

[0303] This embodiment mode can be implemented in appropriate combination with other embodiment modes.

[0304] (Embodiment 7) Batteries that can be used in combination with battery cells containing the materials described in the above embodiments A control unit (Battery Management Unit: BMU) and the battery For transistors suitable for the circuits constituting the pond control unit, see Figures 34 to 40. In this embodiment, the power supply of a power storage device having battery cells connected in series will be described. The pond control unit will now be described.

[0305] When multiple battery cells connected in series are repeatedly charged and discharged, the characteristics between the battery cells The capacity (output voltage) varies depending on the variation in the characteristics of the battery cells connected in series. In the case of a battery with a large capacity, the total discharge capacity depends on the battery cell with the smallest capacity. The capacity during discharge will be smaller. Also, if charging is performed based on a battery cell with a smaller capacity, In addition, if the battery is charged based on the battery cell with the larger capacity, it may be overcharged. There is a risk that this may happen.

[0306] Therefore, the battery control unit of the power storage device having battery cells connected in series It has the function of aligning the capacity variations between battery cells, which can cause short circuits and overcharging. There are several circuit configurations that can be used to equalize the capacitance variation between the capacitors: resistors, capacitors, and insulators. There are other methods such as ductor type, but here we use transistors with low off-current to reduce capacitance variation. An example of a circuit configuration that can achieve uniformity will be described below.

[0307] As a transistor with low off-state current, a transistor having an oxide semiconductor in a channel formation region is An OS transistor with a small off-state current is preferred. By using it in the circuit configuration of the device's battery control unit, the amount of charge leaking from the battery is reduced, It is possible to suppress the decrease in capacity over time.

[0308] The oxide semiconductor used in the channel formation region is In-M-Zn oxide (M is Ga, Sn , Y, Zr, La, Ce, or Nd) is used. In the target, the atomic ratio of metal elements is In:M:Zn=x1:y1:z1. and 、 x1 / y1 is 1 / 3 or more and 6 or less, and further 1 or more and 6 or less, and z1 / y1 is It is preferable that z1 / y1 is 1 / 3 or more and 6 or less, and more preferably 1 or more and 6 or less. When the content is 6 or less, a CAAC-OS film is easily formed as the oxide semiconductor film. .

[0309] Here, the CAAC-OS film will be described.

[0310] The CAAC-OS film is one of the oxide semiconductor films that has multiple crystal parts aligned along the c-axis. .

[0311] Transmission Electron Microscope (TEM) A combined analysis image of the bright-field image and diffraction pattern of the CAAC-OS film was obtained by a microscope. (also called high-resolution TEM image) allows multiple crystals to be identified. On the other hand, the high-resolution TEM image also clearly shows the boundaries between crystals, i.e., grain boundaries. Therefore, the CAAC-OS film is It can be said that the decrease in electron mobility caused by the grain boundaries is unlikely to occur.

[0312] When a high-resolution TEM image of the cross section of the CAAC-OS film was observed from a direction approximately parallel to the sample surface, It can be seen that the metal atoms are arranged in layers in the crystal part. Each layer of metal atoms is The CAAC-OS film is formed on the surface (also called the surface on which the film is formed) or on the upper surface. The CAAC-OS film has a shape similar to that of the crystalline silicon film, and is aligned parallel to the surface on which the CAAC-OS film is formed or the upper surface.

[0313] On the other hand, a high-resolution TEM image of the plane of the CAAC-OS film was observed from a direction almost perpendicular to the sample surface. They then confirmed that the metal atoms in the crystals were arranged in triangular or hexagonal shapes. However, there is no regularity in the arrangement of metal atoms between different crystal parts.

[0314] X-ray diffraction (XRD) of CAAC-OS film When the structure was analyzed using the device, for example, CAAC-OS with InGaZnO4 crystals was In the out-of-plane analysis of the film, the diffraction angle (2θ) peaked at around 31°. This peak is attributed to the (009) plane of the InGaZnO4 crystal. Therefore, the crystals of the CAAC-OS film have a c-axis orientation, and the c-axis faces the surface on which the film is formed or the upper surface. It can be seen that it is oriented in a substantially vertical direction.

[0315] In addition, the out-of-plane crystal structure of the CAAC-OS film with InGaZnO4 crystals In the analysis by the method, in addition to the peak at 2θ near 31°, a peak also appeared at 2θ near 36°. The peak at 2θ of around 36° may be due to the c-axis orientation in some parts of the CAAC-OS film. The CAAC-OS film contains crystals that do not have the 2θ value of about 31°. It is preferable that the spectrum shows a peak at 2θ of about 36° and does not show a peak at 2θ of about 36°.

[0316] The CAAC-OS film is an oxide semiconductor film with a low concentration of impurities. The oxide semiconductor film is preferably made of silicon or a transition metal element other than the main component of the oxide semiconductor film. The elements that bond to oxygen stronger than the metal elements that form the oxide semiconductor film, such as Zn, By removing oxygen from the oxide semiconductor film, the atomic arrangement of the oxide semiconductor film is disturbed, and the crystallinity is reduced. In addition, heavy metals such as iron and nickel, argon, and carbon dioxide are Since the diameter (or molecular radius) of the ions is large, when the ions are contained inside the oxide semiconductor film, the oxide semiconductor film The impurities contained in the oxide semiconductor film are likely to disturb the atomic arrangement of the oxide semiconductor film, which leads to deterioration of the crystallinity. Pure materials may act as carrier traps or carrier generation sources.

[0317] The CAAC-OS film is an oxide semiconductor film with a low density of defect states. Oxygen vacancies in semiconductor films act as carrier traps and trap hydrogen. This can become a carrier generation source.

[0318] The low impurity concentration and low defect level density (low oxygen vacancies) are called high purity intrinsic or The term "high-purity intrinsic" refers to a substantially high-purity intrinsic oxide semiconductor. Since the film has a small number of carrier generation sources, the carrier density can be reduced. The transistor including the oxide semiconductor film has an electrical characteristic in which the threshold voltage is negative. (also called normally-on). An oxide semiconductor film having an intrinsic purity has few carrier traps. Transistors using conductor films have little fluctuation in electrical characteristics and are highly reliable. Note that it takes a certain amount of time for charges trapped in the carrier traps in the oxide semiconductor film to be released. The time it takes for the charge to reach the charge state is long, and it may behave as if it were a fixed charge. A transistor using an oxide semiconductor film having a high density of defect states has unstable electrical characteristics. This may be the case.

[0319] In addition, the electrical characteristics of transistors using CAAC-OS films are improved by irradiation with visible light or ultraviolet light. Gender variation is small.

[0320] Note that an OS transistor is a transistor having silicon in a channel formation region (Si Since the band gap is larger than that of semiconductor transistors, the dielectric breakdown occurs less when high voltage is applied. When battery cells are connected in series, a voltage of several hundred volts is generated. The circuit configuration of the battery control unit of the power storage device applied to such a battery cell includes the above-mentioned O It is suitable to configure it with an S transistor.

[0321] FIG. 34 shows an example of a block diagram of a power storage device. The power storage device BT00 shown in FIG. A terminal pair BT01, a terminal pair BT02, a switching control circuit BT03, and a switching circuit BT 04, a switching circuit BT05, a transformer control circuit BT06, and a transformer circuit BT07, and a battery unit BT08 including a plurality of battery cells BT09 connected to the battery unit BT08.

[0322] In addition, in the power storage device BT00 of FIG. 34, the terminal pair BT01 and the terminal pair BT02 are A switching control circuit BT03, a switching circuit BT04, a switching circuit BT05, and a transformer control circuit The part consisting of the control circuit BT06 and the transformer circuit BT07 is called the battery control unit. You can do it.

[0323] The switching control circuit BT03 controls the operation of the switching circuits BT04 and BT05. Specifically, the switching control circuit BT03 controls the voltage measured for each battery cell BT09. Based on the voltage, the battery cells to be discharged (discharge battery cell group) and the battery cells to be charged (charge Determine the battery cell group.

[0324] Furthermore, the switching control circuit BT03 controls the determined discharge battery cell group and charge battery cell group. The control signal S1 and the control signal S2 are output based on the group of switching signals. This control signal S1 is output to the circuit BT04. The control signal S2 is a signal that controls the switching circuit BT04 to connect the This control signal S2 is output to the switching circuit BT05. This is a signal that controls the switching circuit BT05 so as to connect the

[0325] The switching control circuit BT03 includes a switching circuit BT04, a switching circuit BT05, Considering the configuration of the transformer circuit BT07, between the terminal pair BT01 and the discharge battery cell group, or The control is performed so that terminals of the same polarity are connected between the terminal pair BT02 and the charging battery cell group. The control signal S1 and the control signal S2 are generated.

[0326] The operation of the switching control circuit BT03 will now be described in detail.

[0327] First, the switching control circuit BT03 measures the voltage of each of the multiple battery cells BT09. Then, the switching control circuit BT03, for example, selects the battery cell BT09 having a voltage equal to or higher than a predetermined threshold. A high-voltage battery cell (high-voltage cell), a battery cell with a voltage below a certain threshold BT09 is a low-voltage It is determined that the battery cell is a low voltage cell.

[0328] In addition, various methods can be used to distinguish between high-voltage cells and low-voltage cells. For example, the switching control circuit BT03 selects the most The voltage of each battery cell BT09, which has the highest or lowest voltage, is used as the reference. 09 may be a high-voltage cell or a low-voltage cell. In this case, the switching control circuit BT0 3. Determine whether the voltage of each battery cell BT09 is equal to or greater than a predetermined ratio of the reference voltage. By doing so, it is possible to determine whether each battery cell BT09 is a high-voltage cell or a low-voltage cell. Then, based on the result of this determination, the switching control circuit BT03 switches between the discharge battery cell group and the charge battery cell group. The battery cell group is determined.

[0329] In addition, among the multiple battery cells BT09, high voltage cells and low voltage cells are mixed in various states. For example, the switching control circuit BT03 can The part with the largest number of high-voltage cells connected in series is the discharge battery cell group. The switching control circuit BT03 charges the part with the most low-voltage cells connected in series. The switching control circuit BT03 detects whether a battery is close to being overcharged or overdischarged. The cell BT09 is preferentially selected as a discharge battery cell group or a charge battery cell group. Good too.

[0330] Here, an example of the operation of the switching control circuit BT03 in this embodiment will be described with reference to FIG. FIG. 35 is a diagram for explaining an example of the operation of the switching control circuit BT03. For convenience of explanation, FIG. 35 shows an example in which four battery cells BT09 are connected in series. explain.

[0331] First, in the example of FIG. 35(A), the voltages of the battery cells a to d are voltages Va to Vd. This shows the case where the relationship Va=Vb=Vc>Vd is satisfied. In other words, three consecutive high The high-voltage cells a to c and one low-voltage cell d are connected in series. The control circuit BT03 determines three consecutive high voltage cells a to c as a discharge battery cell group. In addition, the switching control circuit BT03 determines the low-voltage cell d as the charging battery cell group. do.

[0332] Next, the example of FIG. 35(B) shows a case where the relationship is Vc>Va=Vb>>Vd. That is, two consecutive low voltage cells a and b, one high voltage cell c, and one over-discharged cell The nearby low-voltage cell d is connected in series. In this case, the switching control circuit BT03 , the high-voltage cell c is determined as the discharge battery cell group. Since the low-voltage cell d is close to being over-discharged, it is not the two consecutive low-voltage cells a and b that are The voltage cell d is preferentially determined as the charging battery cell group.

[0333] Finally, the example in FIG. 35(C) shows a case where the relationship Va>Vb=Vc=Vd is satisfied. 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 selects the high-voltage cell a as the discharge battery cell group. The switching control circuit BT03 also determines whether to charge three consecutive low-voltage cells b to d. The battery cell group is determined as:

[0334] The switching control circuit BT03 determines the results as shown in the examples of FIGS. 35(A) to 35(C). Based on the result, information indicating the discharge battery cell group to which the switching circuit BT04 is connected is set. The control signal S1 and information indicating the charging battery cell group to which the switching circuit BT05 is connected are The set control signal S2 is sent to the switching circuit BT04 and the switching circuit BT05. Each is output.

[0335] The above is a detailed explanation of the operation of the switching control circuit BT03.

[0336] The switching circuit BT04 responds to a control signal S1 output from the switching control circuit BT03. Therefore, the connection destination of the terminal pair BT01 is changed to the discharge battery determined by the switching control circuit BT03. Set to a group of cells.

[0337] The terminal pair BT01 is composed of a pair of terminals A1 and A2. 4, either one of the terminals A1 and A2 is connected to the most upstream (highest) of the discharge battery cell group. The positive terminal of the battery cell BT09 located in the discharge battery cell group is connected to the positive terminal of the battery cell BT09 located in the discharge By connecting it to the negative terminal of the battery cell BT09 located at the most downstream (low potential side), The connection destination of the child pair BT01 is set. The switching circuit BT04 is set to the control signal S1. The obtained information can be used to identify the location of the discharged battery cell group.

[0338] The switching circuit BT05 responds to a control signal S2 output from the switching control circuit BT03. The connection destination of the terminal pair BT02 is then changed to the rechargeable battery determined by the switching control circuit BT03. Set to a group of cells.

[0339] The terminal pair BT02 is composed of a pair of terminals B1 and B2. 5, either one of the terminals B1 and B2 is connected to the most upstream (highest) of the charging battery cell group. The positive terminal of the battery cell BT09 located in the positive potential side is connected to the positive terminal of the battery cell BT09 located in the positive potential side. By connecting it to the negative terminal of the battery cell BT09 located at the most downstream (low potential side), The connection destination of the child pair BT02 is set. The switching circuit BT05 is set to the control signal S2. The position of the rechargeable battery cell group can be recognized using the obtained information.

[0340] FIG. 36 and FIG. 37 are circuit diagrams showing configuration examples of the switching circuits BT04 and BT05. Shown in Figure 37.

[0341] In FIG. 36, the switching circuit BT04 includes a plurality of transistors BT10 and a bus BT11. The bus BT11 is connected to the terminal A1. 12 is connected to the terminal A2. One of the two is alternately connected to the bus BT11 and the other to the bus BT12. In addition, the other of the sources or drains of the multiple transistors BT10 is connected to two adjacent The battery cell BT09 is connected between the

[0342] Among the multiple transistors BT10, the transistor BT10 located at the most upstream The other of the source and drain is connected to the positive terminal of the battery cell BT09 located at the most upstream of the battery module BT08. The terminals of the transistors BT10 are connected to the downstream terminals of the transistors BT10. The other of the source and drain of the transistor BT10 is located at the most downstream of the battery section BT08. The negative terminal of the battery cell BT09 is connected to the negative terminal of the battery cell BT09.

[0343] The switching circuit BT04 supplies a control signal S1 to the gates of the multiple transistors BT10. In response to the above, one of the plurality of transistors BT10 connected to the bus BT11 and the bus One of the transistors BT10 connected to BT12 is in a conductive state. This connects the discharge battery cell group to the terminal pair BT01. The positive terminal of the battery cell BT09 located most upstream in the cell group is connected to the terminal A1 of the terminal pair or A2. Also, the battery located most downstream in the discharge battery cell group is connected to either The negative terminal of cell BT09 is the other of the terminals A1 and A2 of the terminal pair, i.e., the positive terminal The terminal that is not connected to the input is connected to the other terminal.

[0344] It is preferable to use an OS transistor for the transistor BT10. Since the off-state current of the discharge cell is small, the amount of charge leaking from the battery cells that do not belong to the discharge cell group is small. This reduces the capacitance loss over time. Dielectric breakdown is unlikely to occur when high voltage is applied. Therefore, the output voltage of the discharge battery cell group is large. Even if the voltage is large, the transistor BT10 is in a non-conducting state. The pair BT01 can be insulated.

[0345] In addition, in FIG. 36, the switching circuit BT05 includes a plurality of transistors BT13 and a current control The buses BT15 and BT16 are connected to the control switch BT14 and the bus BT15. T16 is disposed between the plurality of transistors BT13 and the current control switch BT14. The sources or drains of the multiple transistors BT13 are alternately connected to each other. The transistors BT13 are connected to the buses BT15 and BT16. The other of the source and drain of each of the BT09 is connected between two adjacent battery cells BT09. It is being done.

[0346] Among the multiple transistors BT13, the transistor BT13 located at the most upstream The other of the source and drain is connected to the positive terminal of the battery cell BT09 located at the most upstream of the battery module BT08. The terminals of the transistors BT13 are connected to the downstream terminals of the transistors BT13. The other of the source and drain of the transistor BT13 is located at the most downstream of the battery section BT08. The negative terminal of the battery cell BT09 is connected to the negative terminal of the battery cell BT09.

[0347] The transistor BT13 is an OS transistor, similar to the transistor BT10. Since the off-state current of the OS transistor is small, it is preferable that the OS transistor does not belong to the rechargeable battery cell group. This reduces the amount of charge leaking from battery cells and suppresses the loss of capacity over time. In addition, OS transistors are less susceptible to dielectric breakdown when high voltages are applied. , a transistor B that is in a non-conducting state even if the voltage for charging the charging battery cell group is large The battery cell BT09 to which T13 is connected can be insulated from the terminal pair BT02. .

[0348] The current control switch BT14 includes a switch pair BT17 and a switch pair BT18. One end of the switch pair BT17 is connected to the terminal B1. The other end is branched by two switches, one of which is connected to bus BT15 and the other The switch pair BT16 is connected to the bus BT16. One end of the switch pair BT18 is connected to the terminal B2. The other end of the switch pair BT18 is branched into two switches. One switch is connected to bus BT15 and the other switch is connected to bus BT16. do.

[0349] The switches in the switch pairs BT17 and BT18 are transistors BT1 It is preferable to use an OS transistor as in transistors BT10 and BT13.

[0350] The switching circuit BT05 switches the transistor BT13 and the current control By controlling the combination of on / off states of the control switch BT14, Connect the group to terminal pair BT02.

[0351] As an example, the switching circuit BT05 connects the charging battery cell group and the terminal pair BT Connect to 02.

[0352] The switching circuit BT05 supplies a control signal S2 to the gates of the multiple transistors BT13. Depending on the charging status, the positive terminal of the battery cell BT09 located most upstream in the charging battery cell group is connected. The switching circuit BT05 also switches the transistor BT13, which is connected to the In response to a control signal S2 applied to the gate of a number of transistors BT13, The transistor BT1 connected to the negative terminal of the battery cell BT09 located most downstream 3 is put into a conductive state.

[0353] The polarity of the voltage applied to terminal pair BT02 is the same as that of the discharge battery cell connected to terminal pair BT01. The configuration of the battery cell group and the transformer circuit BT07 may vary. To make the current flow in the same direction, the terminals of the same polarity must be connected between the terminal pair BT02 and the charging battery cells. Therefore, the current control switch BT14 is , switch pair BT17 and switch pair B It is controlled to switch the connection destination of T18 respectively.

[0354] As an example, a voltage is applied to terminal pair BT02 such that terminal B1 is positive and terminal B2 is negative. In this case, the most downstream battery cell BT0 When the battery cell group 9 is a charging battery cell group, the switch pair BT17 is connected to the battery cell group 9 by the control signal S2. The switch pair BT17 is controlled to be connected to the positive terminal of the cell BT09. The switch connected to the bus BT16 of the switch pair BT17 of the bus BT On the other hand, the switch pair BT18 is in the OFF state when the control signal S 2, the negative terminal of the battery cell BT09 is controlled to be connected to the negative terminal of the battery cell BT09. The switch connected to the bus BT15 of the switch pair BT18 is turned on, The switch connected to the bus BT16 of BT18 is turned off. Terminals having the same polarity are connected between pair BT02 and the charging battery cell group. The direction of the current flowing from the terminal pair BT02 is controlled so that it is in the direction that charges the rechargeable battery cell group. To be controlled.

[0355] In addition, the current control switch BT14 is connected to the switching circuit B instead of the switching circuit BT05. In this case, the current control switch BT14 responds to the control signal S1. By controlling the polarity of the voltage applied to the terminal pair BT01, The current control switch BT14 controls the polarity of the applied voltage. 2 controls the direction of current flowing to the charging battery cell group.

[0356] FIG. 37 shows a configuration of the switching circuit BT04 and the switching circuit BT05, which is different from that shown in FIG. FIG.

[0357] In FIG. 37, the switching circuit BT04 includes a plurality of transistor pairs BT21 and a bus BT2. The bus BT24 is connected to the terminal A1. The transistor pair BT25 is connected to the terminal A2. Each of them is branched by a transistor BT22 and a transistor BT23. One of the source and drain of the transistor BT22 is connected to the bus BT24. One of the source and drain of the transistor BT23 is connected to the bus BT25. The other ends of the transistor pairs are connected between two adjacent battery cells BT09. Among the multiple transistor pairs BT21, the transistor located at the most upstream The other end of the pair BT21 is connected to the positive terminal of the battery cell BT09 located at the most upstream of the battery unit BT08. In addition, the transistor pair BT21 located at the most downstream The other end of the transistor pair BT21 is connected to the negative terminal of the battery cell BT09 located at the most downstream of the battery section BT08. It is connected to the pole terminal.

[0358] The switching circuit BT04 switches the transistors BT22 and BT31 in response to a control signal S1. By switching the conductive / non-conductive state of the transistor pair BT23, The connection destination is switched to either terminal A1 or terminal A2. If BT22 is conductive, transistor BT23 is non-conductive and is connected to On the other hand, if the transistor BT23 is in a conductive state, the transistor BT2 Transistor BT22 and Transistor BT23 are connected to terminal A2. Which of the resistors BT23 is in a conductive state is determined by a control signal S1.

[0359] To connect the terminal pair BT01 to the discharge battery cell group, two transistor pairs BT21 are used. In detail, the connection of the two transistor pairs BT21 is controlled based on the control signal S1. By determining the destinations, the discharge battery cell group and terminal pair BT01 are connected. The two transistor pairs BT21 are connected to terminal A1 and terminal A2 is controlled by the control signal S1.

[0360] The switching circuit BT05 includes a plurality of transistor pairs BT31, a bus BT34, and a bus B The bus BT34 is connected to the terminal B1. The bus BT35 is 1 and the terminal B2. The output of the transistor BT32 is branched off by the transistor BT33. One end of the second branch is connected to a bus BT34. One end of the branched transistor pair BT3 is connected to a bus BT35. The other end of each of the terminals 1 is connected between two adjacent battery cells BT09. Among the transistor pairs BT31, the other end of the transistor pair BT31 located at the most upstream position is The positive terminal of the battery cell BT09 located at the most upstream of the battery unit BT08 is connected to the positive terminal of the battery cell BT09. In addition, among the plurality of transistor pairs BT31, the transistor pair BT31 located at the most downstream The other end is connected to the negative terminal of the battery cell BT09 located at the most downstream side of the battery unit BT08. do.

[0361] The switching circuit BT05 switches the transistors BT32 and BT33 in response to a control signal S2. By switching the conductive / non-conductive state of the transistor pair BT33, The connection destination is switched to either terminal B1 or terminal B2. If BT32 is conductive, transistor BT33 is non-conductive and is connected to Conversely, if the transistor BT33 is in a conductive state, the transistor BT3 Transistor BT32 and Transistor BT33 are connected to terminal B2. Which of the resistors BT33 is in a conductive state is determined by a control signal S2.

[0362] To connect the terminal pair BT02 to the charging battery cells, two transistor pairs BT31 are used. In detail, the connection of the two transistor pairs BT31 is controlled based on the control signal S2. By determining the destinations, the rechargeable battery cell group and terminal pair BT02 are connected. The two transistor pairs BT31 are connected to terminal B1 and terminal The slave B2 is controlled by the control signal S2.

[0363] The two transistor pairs BT31 are connected to the terminal pair BT02. Specifically, terminal B1 is the positive terminal and terminal B2 is the negative terminal. When a voltage such as this is applied to the terminal pair BT02, the upstream transistor pair BT31 When the transistor BT32 is turned on, the transistor BT33 is turned off. On the other hand, the downstream transistor pair BT31 is controlled by the control signal S2 as follows: The transistor BT33 is turned on and the transistor BT32 is turned off. The terminal B1 is controlled by the control signal S2. The terminal B2 is controlled by the control signal S3. When voltage is applied to terminal pair BT02, the upstream transistor pair BT31 so that the transistor BT33 is in a conductive state and the transistor BT32 is in a non-conductive state. The transistor pair BT31 on the downstream side is controlled by the control signal S2. A control signal S is supplied to the transistor BT32 so that the transistor BT32 is in a conductive state and the transistor BT33 is in a non-conductive state. In this way, the same power supply is provided between the terminal pair BT02 and the charging battery cell group. The terminals with the same polarity are connected together. The direction of the current flowing from the terminal pair BT02 is as follows: The charge battery cell group is controlled in a charging direction.

[0364] The transformer control circuit BT06 controls the operation of the transformer circuit BT07. is the number of battery cells BT09 included in the discharge battery cell group and the number of battery cells BT09 included in the charge battery cell group. A transformer signal S3 for controlling the operation of the transformer circuit BT07 is generated based on the number of the buffer cells BT09. This is generated and output to the transformer circuit BT07.

[0365] The number of battery cells BT09 included in the discharge battery cell group is the number of battery cells BT09 included in the charge battery cell group. If the number of battery cells is greater than the number of BT09, an excessively large charging current may be applied to the charging battery cell group. Therefore, the transformer control circuit BT06 is The transformer circuit BT07 is designed to step down the discharge voltage (Vdis) to a level that allows the battery cells to be charged. The transformer outputs a transformer signal S3 that controls the

[0366] In addition, the number of battery cells BT09 included in the discharge battery cell group is If the number of battery cells BT09 is less than or equal to the number of charging Therefore, the voltage transformer control circuit BT06 controls the charging battery cell group so that Transformer circuit B is designed to boost the discharge voltage (Vdis) to a level where excessive charging voltage is not applied. It outputs a transformer signal S3 that controls T07.

[0367] The voltage value that is considered to be the excessive charging voltage is the voltage value of the battery cell BT09 used in the battery unit BT08. The voltage can be determined based on the product specifications. The applied voltage is applied to the terminal pair BT02 as the charging voltage (Vcha).

[0368] Here, an example of the operation of the transformer control circuit BT06 in this embodiment will be described with reference to FIGS. 38(A) to (C) are diagrams showing the radiation pattern described in FIG. 35(A) to (C). An example of the operation of the transformer control circuit BT06 corresponding to the power battery cell group and the charge battery cell group will be described. 38(A) to (C) are conceptual diagrams showing the battery control unit BT41. As described above, the battery control unit BT41 includes the terminal pair BT01 and the terminal pair BT02, a switching control circuit BT03, a switching circuit BT04, and a switching circuit BT 05, a transformer control circuit BT06, and a transformer circuit BT07.

[0369] In the example shown in FIG. 38(A), three consecutive high voltages are The high-voltage cells a to c and one low-voltage cell d are connected in series. As explained using A), the switching control circuit BT03 discharges the high voltage cells a to c. The low-voltage cell d is determined as the battery cell group, and the low-voltage cell d is determined as the charging battery cell group. The control circuit BT06 is configured to determine the number of battery cells BT09 included in the discharge battery cell group. Based on the ratio of the number of battery cells BT09 included in the charging battery cell group, the discharge voltage (Vd Calculate the conversion ratio N from the current (Vis) to the charging voltage (Vcha).

[0370] The number of battery cells BT09 included in the discharge battery cell group is the same as the number of battery cells BT09 included in the charge battery cell group. If the number of battery cells is greater than BT09, the discharge voltage is not transformed and is applied to the terminal pair BT02. If the voltage is applied as is, the battery cell BT09 in the charging battery cell group will be charged via the terminal pair BT02. Therefore, in the case shown in FIG. So, the charge voltage (Vcha) applied to the terminal pair BT02 is lower than the discharge voltage. Furthermore, in order to charge the battery cell group, the charging voltage must be The voltage of the battery cell BT09 must be greater than the total voltage of the battery cell BT09. BT06 is the charge ratio based on the number of battery cells BT09 included in the discharge battery cell group. The conversion ratio N is set to be greater than the ratio of the number of battery cells BT09 included in the battery cell group.

[0371] The transformer control circuit BT06 determines the number of battery cells BT09 included in the discharge battery cell group as a standard. The conversion ratio N is calculated based on the ratio of the number of battery cells BT09 included in the charging battery cell group. It is preferable to make the charging voltage 1 to 10% higher. At this time, the charging voltage is higher than the voltage of the charging battery cell group. However, the charging voltage is actually equal to the voltage of the battery cell group. The voltage control circuit BT06 converts the voltage of the battery cells into the charging voltage according to the conversion ratio N. This current is supplied to the transformer control circuit BT06 to charge the battery cell group. The value set in

[0372] In the example shown in FIG. 38(A), the number of battery cells BT09 included in the discharge battery cell group is Since the number of battery cells in the charging battery cell group is 1, the voltage control circuit The circuit BT06 calculates a conversion ratio N that is slightly larger than 1 / 3. A circuit BT06 converts the discharge voltage into a charge voltage by converting the discharge voltage into a charge voltage in accordance with the conversion ratio N. 3 to the transformer circuit BT07. The transformer circuit BT07 then outputs The transformed charging voltage is applied to the terminal pair BT02. The battery cell BT09 included in the charging battery cell group is charged by the charging voltage.

[0373] In the examples shown in FIG. 38(B) and FIG. 38(C), the conversion ratio is the same as in FIG. 38(A). In the examples shown in FIG. 38(B) and FIG. 38(C), the number of cells included in the discharge battery cell group is calculated. The number of battery cells BT09 included in the charging battery cell group is less than or equal to the number of battery cells BT09 included in the charging battery cell group. Therefore, the conversion ratio N is equal to or greater than 1. In this case, the transformer control circuit BT06 is It outputs a transformation signal S3 that boosts the discharge voltage and converts it into a charge voltage.

[0374] The transformer circuit BT07 converts the discharge voltage applied to the terminal pair BT01 into a discharge voltage The transformer circuit BT07 converts the converted charging voltage to the terminal pair BT 02. Here, the transformer circuit BT07 applies a voltage between the terminal pair BT01 and the terminal pair BT02. This electrically isolates the BT07 transformer circuit from the most powerful The absolute voltage of the negative terminal of the downstream battery cell BT09 and the lowest This prevents a short circuit caused by the difference in absolute voltage between the negative terminal of the battery cell BT09 located in the downstream. Furthermore, as described above, the transformer circuit BT07 transforms the voltage of the discharge battery cell group based on the transformer signal S3. The total voltage, the discharge voltage, is converted to a charge voltage.

[0375] The transformer circuit BT07 is, for example, an isolated DC (Direct Current)-D In this case, the transformer control circuit BT06 is an isolated DC -The signal that controls the on / off ratio (duty ratio) of the DC converter is the transformation signal S3. By outputting this signal, the charging voltage converted by the transformer circuit BT07 is controlled.

[0376] In addition, there are three types of isolated DC-DC converters: flyback type, forward type, and RCC type. (Ring Choke Converter) method, push-pull method, half There are bridge and full bridge types, but depending on the desired output voltage, An appropriate method is selected depending on the situation.

[0377] The configuration of the transformer circuit BT07 using an isolated DC-DC converter is shown in Figure 39. The DC-DC converter BT51 includes a switch unit BT52 and a transformer unit BT53. The switch unit BT52 switches the operation of the isolated DC-DC converter on and off. A switch, such as a MOSFET (Metal-Oxide-Semiconductor ctor field-effect transistor) and bipolar transistor The switch unit BT52 is realized by using a transformer or the like. Based on the input transformer signal S3, which controls the on / off ratio, the isolated DC-DC converter The switch unit BT51 periodically switches between the on and off states. Various configurations are possible depending on the type of isolated DC-DC converter used. The unit BT53 converts the discharge voltage applied from the terminal pair BT01 into a charge voltage. The transformer unit BT53 operates in conjunction with the on / off state of the switch unit BT52. The discharge voltage is converted to a charge voltage according to the on / off ratio. This charge voltage is In the switching period of 52, the longer the ON time, the larger the capacitance becomes. The time during which the switch unit BT52 is in the ON state is short in the switching period of the switch unit BT52. When using an isolated DC-DC converter, the transformer BT53 Within the terminal pair BT01 and the terminal pair BT02 can be insulated from each other.

[0378] The flow of processing by the power storage device BT00 in this embodiment will be described with reference to FIG. 10 is a flowchart showing the flow of processing by the power storage device BT00.

[0379] First, the power storage device BT00 acquires the voltage measured for each of the multiple battery cells BT09 ( Step S101). Then, the power storage device BT00 aligns the voltages of the multiple battery cells BT09. It is determined whether or not a start condition for the operation is satisfied (step S102). For example, the difference between the maximum and minimum voltages measured for each of the battery cells BT09 is a predetermined If the start condition is not met (step S 102: NO), the voltages of the battery cells BT09 are balanced, so the storage On the other hand, if the start condition is met (step S102: YES), the power storage device BT00 executes a process for making the voltages of the battery cells BT09 uniform. In this process, the power storage device BT00 performs the following on the basis of the measured voltage of each cell: It is determined whether each battery cell BT09 is a high-voltage cell or a low-voltage cell (step S103). The power storage device BT00 then determines the discharge battery cell group and the charge battery cell group based on the determination result. Further, the power storage device BT00 determines the discharge battery cell group A control signal S1 sets the terminal pair BT01 to the connection destination of the terminal pair BT01, and a control signal S2 sets the determined rechargeable battery cell group to the terminal A control signal S2 is generated to set the connection destination of the child pair BT02 (step S105). The device BT00 outputs the generated control signal S1 and control signal S2 to the switching circuits BT04 and The output of the terminals is then output to the switching circuit BT05. The terminal pair BT01 is connected to the discharge battery cell group, and the terminal pair BT0 2 is connected to the discharge battery cell group (step S106). The number of battery cells BT09 included in the discharge battery cell group and the number of battery cells Based on the number of the BT09, a transformed signal S3 is generated (step S107). Based on the transformation signal S3, the power storage device BT00 changes the discharge voltage applied to the terminal pair BT01. The charge voltage is converted to a charging voltage and applied to the terminal pair BT02 (step S108). The charge in the battery cells is transferred to the battery cells.

[0380] In addition, in the flowchart of FIG. 40, multiple steps are listed in order, but each step The order in which the steps are performed is not limited to the order listed.

[0381] As described above, according to this embodiment, when transferring charges from the discharge battery cell group to the charge battery cell group, Like the capacitor method, the charge from the discharged battery cells is first stored and then transferred to the rechargeable battery cells. This eliminates the need for a structure that emits charge to a group of electrons. In addition, the switching circuit BT04 and the switching circuit BT05 can improve the switching efficiency. Therefore, among the discharge battery cell group and the charge battery cell group, the battery cells connected to the transformer circuit are individually can be switched to.

[0382] Furthermore, the number of battery cells BT09 included in the discharge battery cell group is Based on the number of battery cells BT09 included in the charging battery cell group, The applied discharge voltage is converted into a charge voltage and applied to the terminal pair BT02. Regardless of the selection of the discharge and charge side battery cells BT09, the charge can be transferred without any problems. It can be achieved.

[0383] Furthermore, an OS transistor is used for the transistor BT10 and the transistor BT13. As a result, leakage from the battery cell BT09 that does not belong to the charging battery cell group or the discharging battery cell group occurs. This reduces the amount of charge in the battery cell BT0 that does not contribute to charging or discharging. In addition, the OS transistor can suppress the capacitance reduction of the Si transistor. This causes the temperature of the battery cell BT09 to rise. However, normal operation such as switching between conductive and non-conductive states in response to control signals S1 and S2 is possible. It can be used to create works.

[0384] This embodiment mode can be implemented in appropriate combination with other embodiment modes. EXAMPLES

[0385] Example 1 In this example, an example of a method for manufacturing a conductor shown in Embodiment 1 and physical properties of the obtained conductor will be described. and characteristics are described.

[0386] <Preparation of conductor> A method for manufacturing the conductor 201 of one embodiment of the present invention will be described.

[0387] First, graphene oxide is prepared. Graphene oxide is made from flake graphite and Mo The oxidized Hummers process is used, and potassium permanganate and sulfur are used in the oxidation process. The silicon nitride film was formed on the silicon wafer. A solution of graphene oxide dispersed in water was applied to the substrate, and the graphene oxide was observed using an optical microscope. It was estimated that the flake size of graphene oxide is, for example, about 15 μm to 50 μm. Many of the graphene oxide particles were observed. Here is an example.

[0388] Next, the graphene oxide is dispersed in a solvent to prepare a graphene oxide dispersion. Add 600 ml of water to 200 ml of a dispersion of 100% graphene oxide in water. The mixture was added and stirred at 600 rpm for 12 hours to prepare dispersion A.

[0389] Next, graphene oxide dispersion was used as the raw material and graphene was obtained by spray drying. A compound sheet (GO-1) is formed in the chamber of the spray dryer. A GO-1 film is formed on the wall of the device. The details are explained below.

[0390] The spray drying device used was a BUCHI mini spray dryer B-290. The inlet temperature was set to 160°C. The area near the nozzle was heated to a temperature of over 100°C. Dispersion A was fed to the nozzle of the spray dryer at a rate of about 65 ml / min. Dispersion liquid A was injected into the chamber from a nozzle together with nitrogen gas at a flow rate of 60 L / min. was supplied as a spray.

[0391] Dispersion A was supplied to the chamber as a spray, and some of it was converted into graphene oxide powder. The mixture is collected in a collection container, and a part of it is formed as a film on the inner wall of the wall 281a of the cylindrical chamber as GO-1. Figure 41 shows a photograph of the GO-1 film formed on the inner wall.

[0392] Next, the GO-1 is peeled off from the inner wall of the chamber. The GO-1 is made up of multiple oxides stacked on top of each other. The average thickness of the GO-1 was 8.6 μm. Ten points were measured within the range, and the average was calculated. The results are described below. An example of a photograph of GO-1 is shown in Figure 42. Moreover, an optical microscope photograph of GO-1 is shown in FIG. 54(A), and an SEM image is shown in FIG. 54(B).

[0393] Next, GO-1 was subjected to reduction treatment to obtain a conductor. The reduction treatment was carried out under three conditions. Among the obtained conductors, the one that was only thermally reduced at 250°C was named RGO- RGO-1A was thermally reduced at 300°C, while RGO-1B was chemically reduced at 250°C. The product that was thermally reduced at ℃ was named RGO-1C. An example of a photograph of RGO-1C is shown in Figure 43. In addition, optical micrographs of RGO-1A and RGO-1C are shown in Figure 55(A) and (B). In addition, SEM images of RGO-1A and RGO-1C are shown in Figure 56(A) and (B). Show image.

[0394] The reduction treatment reduces the graphene oxide in GO-1, decreasing the oxygen content. RGO-1A to RGO-1C have graphene compounds. RGO-1C is a graphene compound sheet.

[0395] The conditions for chemical reduction are explained below. Ascorbic acid is used as a reducing agent, and An 80% ethanol solution was used. A reducing solution was prepared by adding 0.3375 g of rubic acid and 0.078 g of lithium hydroxide.

[0396] The obtained GO-1 was placed in a reducing solution and reduced at 60 °C for 3 hours. Washing was carried out using ethanol.

[0397] The conditions for thermal reduction are as follows. The heat treatment conditions are 250°C under a reduced pressure of 1 kPa. The above steps were carried out for 0 hours. The sheet-shaped conductors RGO-1A to RGO-1 I got a C.

[0398] <Evaluation of conductors, etc.> Next, the physical properties and characteristics of GO-1, RGO-1A, and RGO-1C are evaluated. explain.

[0399] The electrical conductivity of the obtained sample was measured. The Loresta GP (model number: MCP-T610) manufactured by Epson Corporation was used. The probe was MCP-TP0 Measurements were performed at room temperature using 6P.

[0400] The electrical conductivities of GO-1, RGO-1A, and RGO-1C are 0.0021, 4, and 5, respectively. .2, 6.3 and 25 [S / cm].

[0401] Next, XRD evaluation was performed. XRD evaluation of GO-1, RGO-1A, and RGO-1B The results are shown in Figure 44(A), (B), and (C), respectively. For -1B, samples were produced from different lots with n=2, as shown in Figure 44(B). and (C) shown by solid and dashed lines.

[0402] In Fig. 44(A), (B), and (C), the peaks are located near 9°, 22°, and 23°, respectively. The average interlayer distances were approximately 0.98 nm, 0.40 nm, and 0.75 nm, respectively. 0.39 nm. Here, the vicinity is, for example, the "2θ" obtained by XRD evaluation. In other words, the range of the angle is about 9°. For example, the range of 8.3° to 9.7° or 8.5° to 9.5°. The range is.

[0403] Next, we performed XPS evaluation. First, we show the results for GO-1.

[0404] The quantitative values ​​of elements in GO-1 were evaluated and found to be approximately equal for carbon, oxygen, sulfur, and nitrogen. The results were 63.7, 33.5, 2.3, and 0.6 (units: atomic %), respectively.

[0405] The carbon C1s spectrum is shown in Figure 45(A), and the oxygen O1s spectrum is shown in Figure 45(B). The sulfur S2p spectrum is shown in Figure 46(A), and the nitrogen N1s spectrum is shown in Figure 46(B). , respectively.

[0406] Next, the XPS evaluation results of RGO-1A and RGO-1C are shown.

[0407] The quantitative values ​​of elements in RGO-1A were evaluated and found to be carbon, oxygen, sulfur, and nitrogen. The results were 80.7, 15.8, 1.4, and 2.1 (unit: atomic%), respectively. .

[0408] The quantitative values ​​of elements in RGO-1C were evaluated and found to be carbon, oxygen, sulfur, and nitrogen. The results were 89.5, 9.2, 0.2, and 1.2 (units: atomic%), respectively.

[0409] The carbon c1s spectra of RGO-1A and RGO-1C are shown in Figure 47(A). The oxygen O1s spectrum is shown in Figure 47(B), and the sulfur S2p spectrum is shown in Figure 48(A). The nitrogen N1s spectrum is shown in FIG. 48(B). EXAMPLES

[0410] Example 1 In this example, a manufacturing method of a conductor according to one embodiment of the present invention and its physical properties and characteristics will be described. Reveal.

[0411] <Solvent-based treatment> A solvent was applied to the graphene compound sheet: GO-1 obtained in Example 1. Specifically, NMP was dropped onto GO-1, and then coated with a blade with a gap of 100 μm. The solvent was then evaporated (the graphene compound sheet obtained by the solvent treatment was (This is referred to as GO-2.) NMP was used as the solvent.

[0412] <Reducing> Next, reduction treatment was performed on GO-2. The reduction treatment was performed under two conditions. The first condition was heat-treated at 250℃ for 10 hours, and the second condition was RGO-2A. The product was subjected to a heat treatment at 300°C for 10 hours and named RGO-2B.

[0413] <Evaluation of conductors, etc.> Next, the evaluation results of the physical properties and characteristics of GO-2, RGO-2A, and RGO-2B explain.

[0414] The electrical conductivity of RGO-2A and RGO-2B was 86 and 101 [S / cm]. In addition, the electrical conductivity of GO-2 was below the lower limit of measurement.

[0415] The XRD characterization results of GO-2 and RGO-2A are shown in Figure 49(A) and (B).

[0416] In Figure 49(A), a peak is observed near 8°, and there is also a broader peak near 16°. A sharp peak is observed when the interlayer distance at the peak is about 1.1 nm and about 0.50 nm. This suggests that there is.

[0417] In addition, in FIG. 49(B), a peak is observed near 25°, and the average interlayer distance is about 0.3 Suggested to be 6nm.

[0418] Here, FT The results of the -IR evaluation are shown in Figure 50(A). The dashed line shows the results for GO-1, and the solid line shows the results for GO-2. . The FT-IR technique and measurement conditions were as follows: Attenuated Total The total reflection measurement method is used, and the detector is a cadmium telluride mercury detector. It was used as a vessel.

[0419] As shown in Figure 50(A), GO-1 has C-O, C=C and C=O bonds. The wave numbers that are thought to indicate this are 1250 to 1000 cm -1 , 1620-168 0cm -1 and 1750 to 1650 cm -1 A peak was observed in the range of In GO-2, the intensity ratio and position of the peaks changed, and the peak at 1640 cm -1 Nearby In addition, a strong peak was observed at 1045 cm in GO-1. -1 Nearby The peak was observed. The peak may be due to, for example, a sulfur compound. I believe there is.

[0420] After applying NMP and drying, GO-2 was evaluated by FT-IR, and it was found that, for example, CO bonds This suggests that the types and concentrations of functional groups have changed, such as the decrease in the number of functional groups. The distance between the layers may be expanding. In addition, elements such as nitrogen may be present between the layers, forming intercalation compounds. In Figure 50(B), the 3000 cm -1 Zoom to neighborhood The figure shows the result. -1 Nearby and 2950cm -1 A peak is seen near CH For example, H derived from NMP may be involved. It is possible. EXAMPLES

[0421] In this example, RGO-1A and RGO-1B prepared in Example 1 were used as electrodes. , and constructed a storage battery.

[0422] <Production and evaluation of storage batteries> A storage battery was fabricated using RGO-1A or RGO-1B as the electrode and lithium metal as the counter electrode. The characteristics were evaluated using a CR2032 type (diameter 20 mm, height 3.2 mm) coin-shaped storage battery. A battery was used. The separator was polypropylene. The electrolyte was ethylene glycol. Carbonate (EC) and diethyl carbonate (DEC) were mixed in a volume ratio of 1:1. Dissolve lithium hexafluorophosphate (LiPF6) in the mixed solution at a concentration of 1 mol / L. The positive and negative electrode cans were made of stainless steel (SUS). was used.

[0423] Next, the storage battery was charged and discharged. The measurement temperature was 25°C. The charging was The battery was charged at a constant current with a current density per unit weight of 30 mA / g and an upper limit of 4.8 V. Discharge was performed at a constant current with a current density of 30 mA / g and a lower limit of 2 V. went.

[0424] The charge-discharge characteristics of RGO-1A and RGO-1B are shown in Figure 51(A) and (B). The solid lines represent the samples shown in Figs. 44(B) and (C), and the dashed lines represent the samples shown in Figs. The vertical axis corresponds to the voltage and the horizontal axis corresponds to the sample indicated by the dashed line in (A) and (B). The capacity per weight of RGO-1A or RGO-1B is shown.

[0425] As shown in Figures 51(A) and (B), good charge-discharge characteristics were obtained.

[0426] Here, during charging and discharging, conductors such as RGO-1A and RGO-1B undergo redox reactions. The origin of the high capacity is thought to be the conductive charge generated by the charging and discharging of the storage device. There is a possibility that anions and cations are inserted into and removed from the dielectric 201. The insertion and removal of anions and cations may result in redox reactions. The cation may be a lithium ion or an ion other than the lithium ion contained in the electrolyte. Alternatively, for example, a decomposition product of the electrolyte, such as L, may be applied to the surface of the sheet-like conductor. It is possible that i2CO3 and Li2O are precipitated, and an electrochemical reaction occurs due to peroxide ions. I believe there is. EXAMPLES

[0427] In this example, the GO-1 prepared in Example 1 is used as a current collector, and An example electrode was fabricated as shown in the figure.

[0428] <Synthesis of lithium manganese composite oxide> The active material shown in the second embodiment is used as a raw material, and Li2CO3, MnCO3, and NiO are used. The ratio of Li2CO3:MnCO3:NiO is 0.84:0.8062:0.318. Then, it was sintered at 1000℃ to obtain a lithium manganese composite material with nickel. Sample A, which is an oxide, was prepared.

[0429] <Coating> Next, a graphene oxide dispersion was prepared. The solvent was water. The concentration of graphene oxide was The content was set to 2% by weight.

[0430] The graphene oxide dispersion was adjusted to a content of 6 g. 300 g of sample A was added and mixed to obtain solution A. Then, solution A was heated for 5 minutes under reduced pressure. Heat treatment at 0° C. was carried out to obtain mixture B.

[0431] Next, the heat-treated mixture B is added to the reducing solution and heat-treated at 60°C for 3 hours, and solution C is The reducing solution was prepared by using ascorbic acid as a reducing agent and 80% by volume of ethanol as a solvent. Using an aqueous ethanol solution, lithium hydroxide with a concentration of 3.90 weight% was added to sample A. Ascorbic acid was added to the sample so that the concentration of ascorbic acid was 16.87% by weight based on the sample A.

[0432] Next, solution C was collected using a centrifuge to obtain mixture D. Then, mixture D was poured into a mortar and pestle. The crushed mixture D was then heat-treated at 170°C for 10 hours under reduced pressure to obtain sample E. Sample E had a lithium manganese composite oxide. The lithium manganese composite oxide has nickel and the surface of the lithium manganese composite oxide is coated with a graphene compound. It has been done.

[0433] <Preparation of electrodes> Next, sample E, AB, and PVDF were mixed with NMP to prepare mixture F. The composition of sample E:AB:PVDF=90:5:5 (weight%). Mixture F, which will be 102, was applied onto GO-1. It was then heat-treated at 80°C for 30 minutes and then cooled under N The MP was evaporated. Then, the electrode was pressed using a roll press. Further, a heat treatment was performed at 250° C. for 10 hours to obtain an electrode having a layer 102 on the heat-treated GO-1. The electrode G was obtained. Here, the heat-treated GO-1 was used as a conductive material as shown in the first embodiment. The heat-treated GO-1 is hereafter referred to as conductor 201. Posted.

[0434] Mixture F was applied to an aluminum foil, and then the NMP was evaporated, pressed, and The heat treatment after that was carried out under the same conditions as for electrode G to fabricate electrode H.

[0435] <TEM Observation> The TEM photograph of the cross-section of electrode G is shown in Fig. 57. Also, the photograph observed at a higher magnification is shown in Fig. 58.

[0436] <Evaluation of Electrodes> A storage battery was fabricated using the obtained electrodes G and H. The counter electrode was made of lithium metal. For the evaluation of characteristics, a coin-type storage battery of CR2032 type (diameter 20 mm, height 3.2 mm) was used. Polypropylene was used as the separator. Also, as the electrolyte, a mixed solution of ethylene carbonate (EC) and diethyl carbonate (DEC) mixed at a volume ratio of 1:1 was used, and lithium hexafluorophosphate (LiPF6) was dissolved in the mixed solution at a concentration of 1 mol / liter. Stainless steel (SUS)-formed ones were used as the positive electrode can and the negative electrode can. Here, in terms of per unit area, the weight ratio of sample E to conductor 201 in electrode G was approximately sample E:conductor 201 = 1:0.54.

[0437] Next, charging and discharging of the fabricated storage battery were performed. The measurement temperature was set at 25°C. For charging, the current density per unit weight of sample E was set at 30 mA / g, and constant-current charging was performed with 4.8 V as the upper limit. For discharging, constant-current discharging was performed at 30 mA / g with 2 V as the lower limit.

[0438] The charge-discharge characteristics of the storage battery using electrodes G and H are shown in Fig. 52. Here, electrode G is shown by a solid line, and electrode H is shown by a dotted line, respectively. Fig. 52(A) shows the charge and discharge curves for the first cycle, and Fig. 52(B) shows the charge and discharge curves for the tenth cycle, respectively. ​​Here, the vertical axis indicates the voltage, and the horizontal axis indicates the capacity normalized by the weight of sample E.

[0439] In FIG. 52(B), the discharge capacities of electrodes G and H are 322 mAh / g and 322 mAh / g, respectively. Conductor 201 (corresponding to RGO-1A) had a maximum of 48 mAh / g. Therefore, the maximum contribution of the conductor 201 was 48×0.54=30 [mAh / g]. Therefore, the capacity of electrode G is 30 mAh / g compared to electrode H. However, in FIG. 52(B), electrode G is estimated to be higher than electrode H. The capacity was 63mAh / g, which is large. For example, with the charge / discharge cycle, The capacitance of the conductor 201 may have increased. Alternatively, the capacitance of the conductor 201 and the samples E and AB may have increased. PVDF reacted with the charge and discharge, or NMP used in the preparation of electrode G It is possible that the reaction is somehow contributing to this.

[0440] Next, to investigate the reaction between the layer 102 and the conductor 201, an undercoat was applied to an aluminum current collector. The mixture F was applied onto the sheet 1103 to form a layer 1102. GO-1 was placed on 1102 and heat-treated at 250℃. The conductor is designated as 1201.

[0441] Then, the conductor 1201 was peeled off. The photograph is shown in Figure 59. The area where the conductor 1201 overlapped on the layer 1102 is called area 1. The non-overlapping area is called area2.

[0442] Figure 60 shows the XPS measurement results for area 1 and area 2. Figure 60(A) shows sulfur. Figure 60(B) shows the spectrum of S2P of manganese, and Figure 60(C) shows the spectrum of Mn2p of manganese.

[0443] In the area overlapping with the conductor 1201, a peak was detected suggesting the presence of a sulfur compound. The sulfur concentration detected by XPS was 5.7 atomic % in area 1 and 5.7 atomic % in area 2. was 0 atomic%.

[0444] In addition, in the area overlapping with the conductor 1201, there were few peaks suggesting the presence of manganese. Therefore, in area 1, a layer containing sulfur is formed on layer 1102. The manganese concentration detected by XPS was 0 atomic % in area 1, The sulfur in GO-1 is in contact with the layer 1102. It is possible that the conductor 1201 and layer 1102 reacted with each other. This suggests the possibility. [Explanation of symbols]

[0445] 100 Electricity storage device 101 Electrode 102 layers 103 Active material 107 Separator 111 Positive electrode 111a positive electrode 115 Negative electrode 115a negative electrode 121 Positive electrode current collector 122 Cathode active material layer 123 Separator 125 Negative electrode current collector 126 Negative electrode active material layer 130 Electrode assembly 131 Electrode assembly 151 Electrode 158 Electrolytes 201 Conductors 202 areas 202a area 211 Graphene Compounds 222 Graphene compound sheet 280 Spray Drying Equipment 281 Chamber 282 Nozzle 283 Tube 284 Dispersion 285 Heater 286 Collection Container 287 Substrate 300 Battery 301 Positive electrode can 302 Anode can 303 Gasket 304 Positive electrode 305 Positive electrode current collector 306 Positive electrode active material layer 307 Negative electrode 308 Negative electrode current collector 309 Negative electrode active material layer 310 Separator 321 Graphene Compounds 331 areas 332 areas 333 areas 500 Battery 501 Positive electrode current collector 502 Positive electrode active material layer 503 Positive electrode 504 Negative electrode current collector 505 Negative electrode active material layer 506 negative electrode 507 Separator 508 Electrolyte 509 Exterior body 510 Positive lead electrode 511 Negative lead electrode 514 Sealing part 600 Battery 601 Positive electrode cap 602 Battery Can 603 Positive terminal 604 Positive electrode 605 Separator 606 negative electrode 607 Negative terminal 608 Insulating plate 609 Insulating plate 611 PTC element 612 Safety valve mechanism 900 Circuit Board 910 Label 911 Terminal 912 Circuit 913 Storage battery 914 Antenna 915 Antenna 916 layers 917 layers 918 Antenna 919 Terminal 920 Display device 921 Sensor 922 Terminal 951 Terminal 952 Terminal 980 Energy Storage Device 983 Exterior body 983a Exterior body 983b Exterior body 990 Battery 991 Exterior body 992 Exterior body 993 Wound body 996 Separator 997 Lead Electrode 998 Lead Electrode 1102 layers 1201 Conductors 1700 curved surface 1701 Plane 1702 Curve 1703 Radius of curvature 1704 Center of curvature 1800 Center of curvature 1801 Film 1802 radius of curvature 1803 Film 1804 radius of curvature 7100 Portable display devices 7101 Case 7102 Display section 7103 Operation button 7104 Energy storage devices 7200 Portable Information Terminal 7201 Case 7202 Display section 7203 Band 7204 Buckle 7205 Operation button 7206 Input / output terminal 7207 Icon 7300 display device 7304 Display section 7400 Mobile Phone 7401 Case 7402 Display section 7403 Operation button 7404 External connection port 7405 Speaker 7406 Mike 7407 Energy storage devices 7408 Lead electrode 7409 Current collector 8000 display device 8001 Case 8002 Display section 8003 Speaker section 8004 Electricity storage device 8021 Charging device 8022 Cable 8024 Electricity storage device 8100 Lighting equipment 8101 Case 8102 Light source 8103 Energy storage devices 8104 Ceiling 8105 Side wall 8106 Bed 8107 Window 8200 indoor unit 8201 Case 8202 Ventilator 8203 Energy storage devices 8204 Outdoor unit 8300 Electric refrigerator-freezer 8301 Case 8302 Refrigerator door 8303 Freezer door 8304 Energy storage devices 8400 Automobiles 8401 Headlight 8406 Electric Motor 8500 Automobiles 9600 Tablet PC 9625 Switch 9626 Switch 9627 Power Switch 9628 Operation Switch 9629 Fastener 9630 Case 9630a Case 9630b Case 9631 Display section 9631a Display section 9631b Display section 9632a area 9632b area 9633 Solar Cells 9634 Charge / discharge control circuit 9635 Electric storage unit 9636 DC-DC Converter 9637 Converter 9638 Operation key 9639 Button 9640 Moving parts

Claims

1. carbon atoms are arranged in one atomic layer, and a six-membered ring composed of the carbon atoms is provided; The carbon concentration measured by X-ray photoelectron spectroscopy is greater than 80 atomic % and the oxygen concentration is greater than 2 atomic % and less than 20 atomic %, Electrical conductivity is 0.1 S / cm or more ７ A current collector for a secondary battery, having a portion having a specific surface area of ​​0.2 S / cm or less.

2. carbon atoms are arranged in one atomic layer, and a six-membered ring composed of the carbon atoms and a seven- or higher-membered ring composed of the carbon atoms are included; a region in the vicinity of the poly-membered ring through which lithium ions can pass; The carbon concentration measured by X-ray photoelectron spectroscopy is greater than 80 atomic % and the oxygen concentration is greater than 2 atomic % and less than 20 atomic %, Electrical conductivity is 0.1 S / cm or more ７ A current collector for a secondary battery, having a portion having a specific surface area of ​​0.2 S / cm or less.

3. carbon atoms are arranged in one atomic layer, and a six-membered ring composed of the carbon atoms and a seven- or higher-membered ring composed of the carbon atoms are included; a region in the vicinity of the poly-membered ring through which lithium ions can pass; The carbon concentration measured by X-ray photoelectron spectroscopy is greater than 80 atomic %, and the oxygen concentration is greater than or equal to 2 atomic % and less than or equal to 20 atomic %, and the sulfur concentration is greater than or equal to 10 ppm and less than or equal to 5%. Electrical conductivity is 0.1 S / cm or more ７ A current collector for a secondary battery, having a portion having a specific surface area of ​​0.2 S / cm or less.

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