Lithium ion secondary battery

Abstract

To provide a power storage device whose decrease in capacity along with a charge-discharge cycle is small, a power storage device with a long life, or a power storage device with high reliability.SOLUTION: A power storage device includes a positive electrode, a negative electrode, and an electrolyte solution. The negative electrode includes a first element and carbon. The first element is any of silicon, tin, gallium, aluminum, germanium, lead, antimony, bismuth, silver, zinc, cadmium, and indium. The negative electrode includes an active material, and a first layer in contact with a surface of the active material. The first layer has a thickness of 10 nm or more and 1000 nm or less. The electrolyte solution includes a first cation and a second cation. The first cation is one or more selected from a lithium ion, a sodium ion, a calcium ion, and a magnesium ion. The second cation is an imidazolium cation or a tertiary sulfonium cation.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] In storage batteries that use the reaction of carrier ions, such as lithium ion batteries, charging and discharging The volume of the active material may change during the charging process. It is known that the interlayer distance of graphite increases from 0.336 nm to 0.370 nm. (See Non-Patent Document 1, p. 333-334).

[0005] For example, as described in Patent Document 1, in alloy materials such as silicon, By repeating this process, the shape and volume of the material may change. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2013-214501 A [Non-patent literature]

[0007] [Non-Patent Document 1] Masaki Yoshio et al., “Lithium-Ion Batteries Science and Technologies”, Springer, chapter 16, pp. 333-334. 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 embodiment of the present invention provides a power storage device in which a capacity reduction due to charge / discharge cycles is small. 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. One of the challenges we face is to:

[0010] 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. Alternatively, one embodiment of the present invention is a battery storage device that exhibits little deterioration in characteristics when an external force is repeatedly applied. One object of the present invention is to provide an apparatus.

[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 includes a positive electrode, a negative electrode, and an electrolyte solution. The negative electrode contains a first element and carbon. and the first element is silicon, tin, gallium, aluminum, germanium, It is either lead, antimony, bismuth, silver, zinc, cadmium, or indium. The negative electrode has an active material and a first layer in contact with a surface of the active material, and the first layer has a thickness of 1 The electrolyte has a first cation and a second cation. The first cation is a lithium ion, a sodium ion, a calcium ion, and the second cation is selected from one or more of an imidazolium ion and a magnesium ion. On, or a tertiary sulfonium cation, storage battery.

[0013] Alternatively, one embodiment of the present invention includes a positive electrode, a negative electrode, and an electrolyte solution, and the negative electrode contains a first element. and carbon, and the first element is silicon, tin, gallium, aluminum, germanium, nium, lead, antimony, bismuth, silver, zinc, cadmium, or indium The negative electrode has a first region, a second region in contact with the surface of the first region, and and a third region in contact with the surface of the first region, the second region and the third region having a layered shape. The thickness of the second region is 10 nm or more and 500 nm or less, and the thickness of the third region is 10 nm or more and 500 nm or less. m or more and 1000 nm or less, and the atomic ratio of carbon to the first element in the first region is The atomic ratio of carbon to the first element in the second region is x1:y1. Carbon:first element=x2:y2, and the atomic ratio of carbon to the first element in the third region is Carbon: first element = x3:y3, x1 / y1 is 3 or less, and x2 / y2 is 0.1 x3 / y3 is 5 or more and less than 10, and the electrolyte contains a first cation and a second cation. cations, the first cation being a lithium ion, a sodium ion, a calcium ion, and the second cation is selected from one or more of an imidazolium ion and a magnesium ion. The battery is a storage battery in which the cation is a ternary sulfonium cation.

[0014] In the above-mentioned structure, the second cation is an aromatic cation, an aliphatic onium cation, or As aromatic cations, pyridinium cations, As the aliphatic onium cation, tetrahydrofuran ... Ammonium cations, tertiary sulfonium cations, and quaternary phosphonium cations In the above-mentioned structure, the second cation may be a compound described later. It is preferable to use any of the cations shown in chemical formulas (1) to (17).

[0015] In the above-mentioned structure, the anion may be a monovalent amide anion, a monovalent methide anion, or Anion, fluorosulfonate anion, perfluoroalkylsulfonate anion, tetrafluoroethylene tetrafluoroborate anion, perfluoroalkylborate anion, hexafluoro perfluoroalkylphosphate anion, perfluoroalkylphosphate anion, etc. It is possible.

[0016] Another embodiment of the present invention is an electronic device including any of the above storage batteries. It is also preferable that the electronic device has a display device. It is preferable that the input / output terminal has a function of performing wireless communication.

[0017] Another embodiment of the present invention is a battery control unit including any one of the storage batteries described above. It is. Effect of the Invention

[0018] According to one embodiment of the present invention, a novel electrode can be provided. Thus, a novel power storage device can be provided.

[0019] According to one embodiment of the present invention, a power storage device in which a decrease in capacity due to charge and discharge cycles is small can be provided. According to one embodiment of the present invention, a power storage device having a long lifetime can be provided. According to one embodiment of the present invention, a highly reliable power storage device can be provided. .

[0020] According to one embodiment of the present invention, an electrode having a large capacity can be provided. According to one embodiment of the present invention, a power storage device with high energy density can be provided. According to one aspect of the present invention, there is provided a power storage device in which the characteristics are less deteriorated when an external force is repeatedly applied. It is possible.

[0021] 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]

[0022] [Figure 1] FIG. 2 is a diagram illustrating components of an electrolyte solution. [Diagram 2] 1A to 1C are diagrams illustrating particles according to one embodiment of the present invention. [Diagram 3] FIG. 4 is a diagram illustrating a part of a cross section of an electrode. [Figure 4] FIG. [Diagram 5] FIG. 1 is a cross-sectional view of a storage battery. [Figure 6] 1A to 1C are diagrams illustrating a method for manufacturing a storage battery. [Figure 7] 1A to 1C are diagrams illustrating a method for manufacturing a storage battery. [Figure 8] FIG. [Figure 9] 1A to 1C are diagrams illustrating a method for manufacturing a storage battery. [Figure 10] 1A to 1C are diagrams illustrating a method for manufacturing a storage battery. [Figure 11] 1A to 1C are diagrams illustrating a method for manufacturing a storage battery. [Figure 12] 1A to 1C are diagrams illustrating a method for manufacturing a storage battery. [Figure 13] FIG. 4 is a diagram for explaining the radius of curvature of a surface. [Figure 14] FIG. 2 is a diagram for explaining the radius of curvature of a film. [Figure 15]FIG. 1 is a diagram illustrating a coin-type storage battery. [Figure 16] FIG. 1 is a diagram illustrating a cylindrical storage battery. [Figure 17] FIG. 2 is a cross-sectional view illustrating a portion of a storage battery. [Figure 18] FIG. 2 is a cross-sectional view illustrating a portion of a storage battery. [Figure 19] FIG. 2 is a cross-sectional view illustrating a portion of a storage battery. [Figure 20] FIG. 1 shows an example of a storage battery. [Figure 21] FIG. 1 shows an example of a storage battery. [Figure 22] 1A and 1B are diagrams for explaining examples of power storage systems. [Diagram 23] 1A and 1B are diagrams for explaining examples of power storage systems. [Figure 24] 1A and 1B are diagrams for explaining examples of power storage systems. [Diagram 25] 1A to 1C are diagrams illustrating examples of electronic devices. [Figure 26] 1A to 1C are diagrams illustrating examples of electronic devices. [Figure 27] 1A to 1C are diagrams illustrating examples of electronic devices. [Figure 28] 1A to 1C are diagrams illustrating examples of electronic devices. [Figure 29] FIG. 1 is a block diagram illustrating one embodiment of the present invention. [Diagram 30] FIG. 1 is a conceptual diagram illustrating one embodiment of the present invention. [Diagram 31] FIG. 1 is a circuit diagram illustrating one embodiment of the present invention. [Diagram 32] FIG. 1 is a circuit diagram illustrating one embodiment of the present invention. [Diagram 33] FIG. 1 is a conceptual diagram illustrating one embodiment of the present invention. [Diagram 34] FIG. 1 is a block diagram illustrating one embodiment of the present invention. [Diagram 35] 1 is a flowchart illustrating one embodiment of the present invention. [Diagram 36] CV measurement results. [Figure 37] CV measurement results. [Figure 38] CV measurement results. [Figure 39] CV measurement results. [Diagram 40] CV measurement results. [Diagram 41] CV measurement results. [Diagram 42] FIG. [Diagram 43] FIG. [Diagram 44] XPS analysis results. [Diagram 45] XPS analysis results. [Figure 46] XPS analysis results. [Figure 47] Cross-sectional TEM observation results. [Figure 48] Cross-sectional TEM observation results. [Figure 49] Cross-sectional observation image and EDX analysis results. [Figure 50] Cross-sectional observation image and EDX analysis results. [Figure 51] EDX analysis results. [Figure 52] Cross-sectional image and EELS analysis results. [Figure 53] Cross-sectional image and EELS analysis results. [Figure 54] FIG. 2 illustrates a negative electrode of one embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] (Embodiment 1) In this embodiment, a storage battery according to one embodiment of the present invention will be described.

[0029] A storage battery according to one embodiment of the present invention includes a positive electrode, a negative electrode, and an electrolyte.

[0030] The electrolyte solution in the storage battery of one embodiment of the present invention preferably contains an ionic liquid. The storage battery according to one embodiment of the present invention has a first cation in addition to the ions constituting the ionic liquid. As the first cation, for example, an alkali metal ion and an alkali Alkali metal ions and alkaline earth metal ions can be used. The ions function as carrier ions in the battery.

[0031] Alkali metals include lithium, sodium, and potassium. The potassium earth metals include calcium, strontium, barium, beryllium, and magnesium. Examples include magnesium.

[0032] When lithium is used as the carrier ion, the ionic liquid may contain, for example, LiPF6, Li ClO4, LiAsF6, LiBF4, LiAlCl4, LiSCN, LiBr, LiI , Li2SO4, Li2B 10 Cl 10 , Li2B 12 Cl 12 , LiCF3SO3, L iC4F9SO3, LiC(CF3SO2)3, LiC(C2F5SO2)3, LiN( CF3SO2)2, LiN(C4F9SO2)(CF3SO2), LiN(C2F5SO 2) One or more of the lithium salts such as 2) in any combination and ratio. It can be dissolved at a rate of 1000 ppm.

[0033] Here, the concentration of the carrier ions is greater than 0.1 mol / L and less than 3 mol / L. It is preferable that the concentration is 0.3 mol / L or more and 2.5 mol / L or less. It is.

[0034] The electrolyte may contain a solvent other than the ionic liquid. For example, an aprotic organic solvent. The aprotic organic solvent may be, for example, ethylene carbonate (EC). , Propylene carbonate (PC), Butylene carbonate, Chloroethylene carbonate Vinylene carbonate, γ-butyrolactone, γ-valerolactone, dimethyl carbonate diethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EM C) Methyl formate, Methyl acetate, Methyl butyrate, 1,3-dioxane, 1,4-dioxane , dimethoxyethane (DME), dimethyl sulfoxide, diethyl ether, methyl diethyl Lime, acetonitrile, benzonitrile, tetrahydrofuran, sulfolane, sultone These may be used alone or in any combination and ratio of two or more of them. Cut.

[0035] During charging and discharging of the battery, decomposition reactions of the electrolyte may occur. The solution occurs primarily through electrical reactions near the surface of the electrodes.

[0036] Storage battery using alkali metal ions and alkaline earth metal ions as carrier ions In some cases, the reaction potential of the negative electrode is low and the decomposition reaction of the electrolyte may occur easily. For example, consider the case where the electrolyte decomposes due to a reduction reaction near the surface of the negative electrode. If the solution is an irreversible reaction, the irreversible capacity may increase. is the difference between the charge capacity and the discharge capacity. The increase in irreversible capacity reduces the capacity of the storage battery.

[0037] In order to suppress the decrease in the capacity of a storage battery, it is necessary to prevent the irreversible reaction of the electrolyte near the electrode surface. For example, it is preferable to suppress the main carrier ions among the components of the electrolyte. Promotes the reaction of certain alkali metal ions and alkaline earth metal ions and other components It is preferred to suppress reactions with elements such as the cations and anions of the ionic liquid.

[0038] FIG. 1(A) is a schematic diagram showing each component of the electrolyte on the surface of the negative electrode active material 671 of the storage battery. 1 is a schematic diagram of an electrolyte solution having a first cation 681 and an ionic liquid. has a cation 682 and an anion 683. As an example, the first cation 681 Lithium ion, cation 682, 1-ethyl-3-methylimidazole dazolium (EMI) can be used.

[0039] Lithium has an extremely low redox potential, with a potential of -3.045 V relative to the standard electrode potential. The lower the reaction potential of the negative electrode active material, the higher the voltage of the power storage device can be. On the other hand, when the potential is low, the power to reduce the electrolyte is also strong. The organic solvents used in the solution may be subject to reduction and decomposition. Compared to the redox potential of lithium, , the reaction potential at the negative electrode of a lithium-ion battery is the same or slightly higher. In this case, the voltage of the power storage device can be increased, which is preferable. For example, the reaction potential of the cation in the ionic liquid is higher than the redox potential of lithium. There are many matches.

[0040] The potential of the negative electrode active material 671 decreases as the storage battery is charged. A potential at which the reaction between the first cation 681, the cation 682, and the anion 683 occurs significantly Before reaching the negative electrode, charge is accumulated in the negative electrode. As the charge accumulates, the As shown in FIG. 1, the first cation 681 can form an electric double layer on the surface of the negative electrode active material 671. In addition, the surface of the electric double layer formed by the first cation 681 may contain, for example, an anion. In FIG. 1B, the cations 682 are arranged on the surface of the negative electrode active material 671. is suppressed from reaching

[0041] If the reaction potential of the cation 682 is higher than the reaction potential of the first cation 681, the reaction potential is negative. As the potential of the electrode decreases to the reaction potential of cation 682, the reaction of cation 682 becomes evident. However, as shown in FIG. 1(B), the arrival of cations 682 on the negative electrode surface is suppressed, the reaction potential of the first cation 681 is reached, and then the reaction potential of the cation 6 82 reactions can be suppressed.

[0042] Next, when the potential of the negative electrode is decreased to a potential at which the reaction of the first cation 681 occurs significantly, Consider the following. The reduction reaction of the first cation 681 consumes the first cation 681. With the reduction of the first cation 681, for example, the first cation 681 and the negative electrode active material 671 Alternatively, the first cation 681 may be reduced to form a compound of In some cases, the negative electrode active material 671 may be oxidized to form a precipitate layer 681b on the surface thereof.

[0043] Here, as the first cation 681 is consumed, the negative electrode active material 671 is formed on the surface of the negative electrode active material 671. The electric double layer disappears, and new cations reach the surface of the negative electrode active material 671. When the cation 682 reaches the surface of the negative electrode active material 671, the inclusion of the cation 682 Reversible reactions, such as reductive decomposition, may occur to form reactant 684. 4 may accumulate on the surface of the negative electrode active material 671 to form a coating 685 .

[0044] Therefore, the first cations 681 reach the surface of the negative electrode active material 671 faster than the cations 682. For example, as shown in FIG. 1(D), If the diffusion rate of thione 681 is faster than that of cation 682, the reaction of cation 682 This suppresses the reaction of the first cation 681, which is the main carrier ion, and promotes the reaction of the first cation 681. Cut.

[0045] Here, let us consider the case where an aprotic organic solvent is used as the solvent for the electrolyte. The solvent coordinates (solvates) with thione 681. Here, the main carrier ion is When the first cation 681 moves to the vicinity of the negative electrode surface and forms an electric double layer, the solution Since the solvent is neutral, it moves in a solvated state to the vicinity of the negative electrode surface and reacts with the first cation 68 1 may inhibit the formation of an electric double layer.

[0046] On the other hand, when an ionic liquid is used as a solvent for the electrolyte, the first cation 681 is an a It is believed that the anion 683 is coordinated. The first cation 681 moves to the vicinity of the negative electrode surface. However, when forming an electric double layer, the anion 683 has a negative charge, so it is removed from the negative electrode surface. Therefore, as the first cation 681 approaches the negative electrode surface, It is believed that the coordination force of the anion 683 weakens and is eliminated. Compared with the case where an aprotic organic solvent is used as the solvent, the electric double layer of the first cation 681 It is thought that the formation of

[0047] [Cation diffusion rate] In the electrolyte of the storage battery according to one embodiment of the present invention, the diffusion rate of the first cation 681 is The diffusion rate of the cation is preferably faster than that of thione 682. The diffusion rate of the cation depends on the molecular weight, the charge It is determined by load distribution, three-dimensional structure, etc.

[0048] For example, when the molecular weight of the cation 682 is large, the diffusion rate of the cation 682 is small. However, this leads to an increase in the viscosity of the electrolyte. The diffusion rate of the first cation 681 also decreases. As the temperature drops, the output characteristics of the storage battery decrease.

[0049] As the cation 682, an aromatic cation, an aliphatic onium cation, etc. can be used. As aromatic cations, pyridinium cations and imidazolium cations are available. As the aliphatic onium cation, a quaternary ammonium cation, Tertiary sulfonium cations, quaternary phosphonium cations, and the like can be used.

[0050] As an example of an ionic liquid having an imidazolium cation, there is used an ionic liquid represented by the following general formula (G1): In the general formula (G1), an ionic liquid having R 1 has one carbon atom R represents an alkyl group having 4 or more radicals; 2 ~R 4 each independently represents a hydrogen atom or a carbon atom R5 is an alkyl group or C, O, Si, N It represents a main chain composed of two or more atoms selected from the group consisting of R, S, and P. 5 Placed on the main chain of Substituents may be introduced. Examples of the substituents to be introduced include alkyl groups, aryl groups, and the like. Examples include a koxy group.

[0051] [ka]

[0052] As an example of an ionic liquid having a tertiary sulfonium cation, there is used an ionic liquid represented by the following general formula (G2): In the general formula (G2), R 25 ~R 27 each independently represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a phenyl group. represents a aryl group, or R 25 ~R 27 As atoms of C, O, Si, N, S, and P Alternatively, a main chain composed of two or more selected from the above may be used.

[0053] [ka]

[0054] As an example of an ionic liquid having a quaternary ammonium cation, there is an ionic liquid represented by the following general formula (G4): Ionic liquids represented by (G5) and (G6) can be used.

[0055] [ka]

[0056] In general formula (G4), R 12 ~R 17 each independently represents a group having 1 to 20 carbon atoms Any of an alkyl group, a methoxy group, a methoxymethyl group, a methoxyethyl group, or a hydrogen atom. Represents one of the following.

[0057] [ka]

[0058] In general formula (G5), R 18 ~R 24 each independently represents a group having 1 to 20 carbon atoms Any of an alkyl group, a methoxy group, a methoxymethyl group, a methoxyethyl group, or a hydrogen atom. Represents one of the following.

[0059] [ka]

[0060] In the general formula (G6), n and m are 1 or more and 3 or less. α is 0 or more and 6 or less. When n is 2, α is 0 to 5, and when n is 3, α is β is 0 to 6 inclusive, and when m is 1, β is 0 to 4 inclusive, and m When m is 2, β is 0 to 5, and when m is 3, β is 0 to 6. When α or β is 0, it means that the group is unsubstituted. In addition, the case where both α and β are 0 is excluded. X or Y is a straight-chain or branched-chain alkyl group having 1 to 4 carbon atoms as a substituent. an alkyl group having 1 to 4 carbon atoms, a linear or branched alkoxy group having 1 to 4 carbon atoms, or It represents a linear or branched alkoxyalkyl group having a number of 1 to 4.

[0061] As an example of an ionic liquid having a pyridinium cation, there is a compound represented by the following general formula (G3): In the general formula (G3), an ionic liquid having R 6 is an alkyl group, or represents a main chain composed of two or more atoms selected from the group consisting of C, O, Si, N, S, and P; R 7 ~R 11 each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. Also, R 6 A substituent may be introduced into the main chain of the above-mentioned compound. For example, an alkyl group or an alkoxy group can be mentioned.

[0062] [ka]

[0063] The anion 683 can be used as A- in the general formulas (G1) to (G6). See anion.

[0064] When a pyridinium cation having a molecular weight of 150 or less is used as the cation 682, Cation 682 diffuses quickly through the electrolyte, and reaches the negative electrode surface where it undergoes a decomposition reaction. On the other hand, cation 682 is a tertiary sulfonate with a molecular weight of 110 or more. imidazolium cations with molecular weights of 100 or more, and imidazolium cations with molecular weights of 130 or more By using the above quaternary ammonium cation, the cations were reduced compared to the first cation 681. This is preferable because it may be possible to reduce the diffusion rate of thione 682. and a molecular weight of 250 or less, more preferably 175 or less. By using the imidazolium cation, the increase in the viscosity of the electrolyte can be suppressed. This may be possible and is preferable.

[0065] Ionic liquids represented by general formulas (G1) to (G6) as an embodiment of the present invention It is preferable to use ionic liquids represented by the general formulas (G1) and (G2). It is more preferable to use an ionic liquid represented by general formula (G1). stomach.

[0066] Anion 683: Monovalent amide anions, monovalent methide anions, fluoro Sulfonate anion, perfluoroalkylsulfonate anion, tetrafluoroborane perfluoroalkylborate anion, hexafluorophosphate anion On (PF6 - ), or perfluoroalkyl phosphate anion, etc. can be used. can.

[0067] Examples of anion 683 include monovalent amide anions, monovalent methide anions, and fluorine anions. Fluorosulfonate anion (SOF - ), fluoroalkylsulfonate anion, etc. It is preferable to use

[0068] As monovalent amide anions, (C n F 2n+1 SO2)2N - (n=0 or more and 3 or more (Below) As a monovalent cyclic amide anion, (CF2SO2)2N - etc. 1 The methide anions of the valence are (C n F 2n+1 SO2)3C - (n=0 or more and 3 or less) As a monovalent cyclic methide anion, (CF2SO2)2C - (CF3SO2) Examples of fluoroalkylsulfonate anions include (C m F 2m+1 SO3) - (m = 0 to 4). Fluoroalkylborate anions include {BF n (C m H k F 2m+1-k ) 4-n} - (n=0 to 3, m=1 to 4, k= 0 to 2m). Fluoroalkyl phosphate anions include {PF n (C m H k F 2m+1-k )6-n} - (n=0 to 5, m=1 to 4, k= These anions include the first cation 681 and the cation The interaction between the first cation 681 and the anion 682 may be small, which is preferable. When the interaction with 3 is small, the diffusion rate of the first cation 681 can be increased. In addition, when the interaction between the cation 682 and the anion 683 is small, The melting point of the ionic liquid contained in the electrolyte may be lowered.

[0069] Examples of monovalent amide anions include bis(fluorosulfonyl)amide anion and and bis(trifluoromethanesulfonyl)amide anions can be used.

[0070] In addition, the anion 683 is the tetrafluoroborate anion (BF4 - ), Fluo Alternatively, fluoroalkylborate anions or fluoroalkylphosphate anions may be used. good.

[0071] The compound used in the power storage device of one embodiment of the present invention is a compound represented by General Formula (G7). The cation has a corresponding anion and a corresponding anion.

[0072] [ka]

[0073] In the formula, R 1 represents an alkyl group having 1 to 4 carbon atoms, and R 2 ~R 4 are respectively Each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. 1 No To A4 each independently represents a methylene group or an oxygen atom; A 1 or A 4 At least The other is an oxygen atom.

[0074] The substituent introduced to the nitrogen of the imidazolium cation (A in general formula (G7) 1 or A 4 The presence of a substituent containing aryl groups increases the steric bulkiness of the cationic species in the ionic liquid, which increases the charge transport. Side reactions in the battery (cation insertion and decomposition into graphite during charging, and the associated gas generation) However, A 1 or A 4 As the number of carbon atoms increases, The viscosity of the electrolyte also tends to increase, so depending on the desired charge / discharge efficiency and the desired viscosity, It is preferable to control it appropriately.

[0075] The anion in the ionic liquid is composed of an imidazolium cation and an ionic liquid. The anion is, for example, a monovalent amide anion, Monovalent methide anions, fluorosulfonate anions (SOF - ), Fluoroalkyl sulfonic acid anion, tetrafluoroborate anion (BF4 - ), Fluoroalkyl Boron anion, hexafluorophosphate anion (PF6 - ) or Fluoro Examples of the monovalent amide anion include alkyl phosphate anion and the like. is (C n F 2n+1 SO2)2N - (n = 0 to 3), monovalent cyclic amide aniline On is (CF2SO2)2N - As monovalent methide anions, (C n F 2n+1 SO2)3C - (n = 0 to 3), monovalent cyclic methide anion As for (CF2SO2)2C - (CF3SO2), etc. The phonate anion is (C m F 2m+1 SO3) - (m=0 to 4) Fluoroalkylborate anions include {BF n (C m H k F 2m+1-k )4 -n} - (n = 0 to 3, m = 1 to 4, k = 0 to 2m), etc. The fluoroalkyl phosphate anion is {PF n (C m H k F 2m+1-k )6 -n} - (n = 0 to 5, m = 1 to 4, k = 0 to 2m), etc. However, the anion is not limited to these.

[0076] The anion in the ionic liquid is a monovalent amide anion, bis(fulu). Preferably, the anion is a bis(fluorosulfonyl)amide anion. Ionic liquids using a combination of neutral anions and cations have high conductivity and relatively low The ionic liquid has a low viscosity. A storage device using this ionic liquid and graphite for the negative electrode is capable of charging and discharging. be.

[0077] A compound used in a power storage device of one embodiment of the present invention is represented by General Formula (G8): The cation has a corresponding anion and an anion corresponding to the cation.

[0078] [ka]

[0079] In the formula, R 1 represents an alkyl group having 1 to 4 carbon atoms, and R 2 ~R 4 are respectively Each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.

[0080] The anion in the ionic liquid is composed of an imidazolium cation and an ionic liquid. The anion is, for example, a monovalent amide anion, Monovalent methide anions, fluorosulfonate anions (SOF - ), Fluoroalkyl sulfonic acid anion, tetrafluoroborate anion (BF4 - ), Fluoroalkyl Boron anion, hexafluorophosphate anion (PF6 - ) or Fluoro Examples of the monovalent amide anion include alkyl phosphate anion and the like. is (C n F 2n+1 SO2)2N - (n = 0 to 3), monovalent cyclic amide aniline On is (CF2SO2)2N - As monovalent methide anions, (C n F 2n+1 SO2)3C - (n = 0 to 3), monovalent cyclic methide anion As for (CF2SO2)2C - (CF3SO2), etc. The phonate anion is (C m F 2m+1 SO3) -(m=0 to 4) Fluoroalkylborate anions include {BF n (C m H k F 2m+1-k )4 -n} - (n = 0 to 3, m = 1 to 4, k = 0 to 2m), etc. The fluoroalkyl phosphate anion is {PF n (C m H k F 2m+1-k )6 -n} - (n = 0 to 5, m = 1 to 4, k = 0 to 2m), etc. However, the anion is not limited to these.

[0081] The anion in the ionic liquid is preferably a monovalent amide anion. It is nice.

[0082] A compound used in a power storage device of one embodiment of the present invention is represented by General Formula (G9): The cation has a corresponding anion and an anion corresponding to the cation.

[0083] [ka]

[0084] In the formula, R 1 represents an alkyl group having 1 to 4 carbon atoms, and R 2 ~R 4 are respectively Each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.

[0085] The anion in the ionic liquid is composed of an imidazolium cation and an ionic liquid. The anion is, for example, a monovalent amide anion, Monovalent methide anions, fluorosulfonate anions (SOF - ), Fluoroalkyl sulfonic acid anion, tetrafluoroborate anion (BF4 - ), Fluoroalkyl Boron anion, hexafluorophosphate anion (PF6 - ) or Fluoro Examples of the monovalent amide anion include alkyl phosphate anion and the like. is (C n F 2n+1 SO2)2N - (n = 0 to 3), monovalent cyclic amide aniline On is (CF2SO2)2N - As monovalent methide anions, (C n F 2n+1 SO2)3C - (n = 0 to 3), monovalent cyclic methide anion As for (CF2SO2)2C - (CF3SO2), etc. The phonate anion is (C m F 2m+1 SO3) - (m=0 to 4) Fluoroalkylborate anions include {BF n (C m H k F 2m+1-k )4 -n} - (n = 0 to 3, m = 1 to 4, k = 0 to 2m), etc. The fluoroalkyl phosphate anion is {PF n (C m H k F 2m+1-k )6 -n} - (n = 0 to 5, m = 1 to 4, k = 0 to 2m), etc. However, the anion is not limited to these.

[0086] The anion in the ionic liquid is preferably a monovalent amide anion. It is.

[0087] The alkyl group of the ionic liquids represented by the general formulas (G7) to (G9) is It may be linear or branched. For example, ethyl group, tert-butyl group In addition, the ionic liquid represented by the general formula (G7) is 1 or A 4 is an oxygen-oxygen bond It is preferable to have no peroxides. The single bond between oxygen and oxygen is very fragile. However, it is highly reactive and may be explosive, making it unsuitable for use in power storage devices.

[0088] Specific examples of the cation of the above general formula (G1) include those represented by structural formulas (111) to ( 174) is one example.

[0089] [ka]

[0090] [ka]

[0091] [ka]

[0092] [ka]

[0093] [ka]

[0094] [ka]

[0095] [ka]

[0096] Specific examples of the cation of the above general formula (G2) include, for example, the following structural formulas (201) and (202): Examples include the formula (215).

[0097] [ka]

[0098] [Negative electrode active material] When a negative electrode active material is used as the active material, for example, an alloy-based material or a carbon-based material may be used. can.

[0099] 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.

[0100] As described in Patent Document 1, for example, alloy materials such as silicon are subject to alloying reactions with lithium. It is known that the volume of the lithium-ion battery expands due to the dealloying reaction with lithium. Contraction occurs due to the reaction. The negative electrode active material expands and contracts as the battery is charged and discharged. .

[0101] When the negative electrode active material is in an expanded state, a coating 685 is formed on the surface of the negative electrode active material. After that, the negative electrode active material shrinks with the coating 685 formed on the surface. Stress is generated from the coating 685 to the electrode active material, and cracks are likely to form in the negative electrode active material. In addition, during shrinkage, the coating 685 gets caught in the cracks, and It is considered that the negative electrode active material may crack or the active material may become pulverized. On the surface, there is a mixed region of finely powdered negative electrode active material and a coating film wrapped between the negative electrode active material. The finely pulverized negative electrode active material may lose electrical conductivity. Loss of charge / discharge reaction may not occur and may result in a decrease in the capacity of the storage battery. Therefore, it is preferable to suppress cracking and pulverization of the negative electrode active material.

[0102] In this specification, SiO refers to, for example, silicon monoxide. Alternatively, SiO refers to Si It can also be expressed as Ox, where x preferably has a value close to 1. For example, x is The ratio is preferably 0.2 or more and 1.5 or less, and more preferably 0.3 or more and 1.2 or less.

[0103] Carbon-based materials include graphite, graphitizable carbon (soft carbon), and non-graphitizable carbon (hard carbon). Carbon nanotubes, graphene, carbon black, etc. stomach.

[0104] 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.

[0105] 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.

[0106] When lithium ions are inserted into graphite, for example, the interlayer distance of the graphite is 0. It is known that the wavelength increases from 336 nm to 0.370 nm (Non-Patent Document 1, p. 33 3-334). In other words, the interlayer distance increases by about 11%.

[0107] 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.

[0108] 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.

[0109] 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.

[0110] 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 CoS0.89 , 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.

[0111] [Pre-Dope] In addition, when a film is formed during the first charge and discharge, an irreversible reaction occurs. If the irreversible reaction at either the positive or negative electrode is greater, the charge / discharge balance will be disrupted. After charging and discharging using the counter electrode, the electrodes should be recombined. For example, by combining a positive electrode with a negative electrode, the capacity loss can be suppressed. After charging or discharging the battery by combining the two, remove the positive electrode used for charging or discharging. By removing the old positive electrode and combining it with a new positive electrode to create a storage battery, the decrease in capacity of the storage battery can be suppressed. This method is sometimes called pre-doping or pre-aging.

[0112] By suppressing the formation of the coating 685 on the surface of the negative electrode active material, cracks in the negative electrode active material are prevented. , and pulverization may be suppressed.

[0113] The negative electrode of one embodiment of the present invention preferably contains the first element and carbon. The first elements are silicon, tin, gallium, aluminum, germanium, lead, and antimony. Preferably, the metal is one of tin, bismuth, silver, zinc, cadmium, or indium. stomach.

[0114] [Layer of negative electrode] The negative electrode of one embodiment of the present invention has a negative electrode active material and a first layer on the surface of the negative electrode active material. Here, the first layer may be called a coating. The thickness of the first layer is 10 nm or more and 1000 nm or less. Preferably, the thickness is 50 nm or less and 200 nm or less, more preferably, 50 nm or more and 100 nm or less. Bottom is even better.

[0115] Alternatively, the negative electrode of one embodiment of the present invention includes a first region and a second region in contact with a surface of the first region. The second region and the third region are in contact with a surface of the second region. The second region has a layer shape. The thickness of the second region is preferably 10 nm or more and 500 nm or less. More preferably, the thickness is 50 nm or more and 200 nm or less, and even more preferably, the thickness is 50 nm or more and 100 nm or less. The thickness of the third region is preferably 10 nm or more and 1000 nm or less, and more preferably 50 nm or more and 20 The thickness of the first region is preferably 0 nm or less, and more preferably 50 nm or more and 100 nm or less. The atomic ratio of carbon to the first element in the second region is x1:y1, and the atomic ratio of carbon to the first element in the second region is x1:y1. The atomic ratio of carbon and the first element in the third region is x2:y2. The numerical ratio is x3:y3. x1 / y1 is preferably 3 or less, and more preferably 1.5 or less. x2 / y2 is preferably 0.1 or more and less than 10, and more preferably 0.3 or more and 5 or less. y3 is preferably 5 or more, more preferably 10 or more, and even more preferably 20 or more.

[0116] The intensity ratio of carbon to the first element in the first region obtained by EDX analysis is defined as x1:y 1, the intensity ratio of carbon to the first element in the second region is x2:y2, and the intensity ratio of carbon to the first element in the third region is x2:y2. The intensity ratio of carbon to the first element is x3:y3. x1 / y1 is preferably 0.3 or less. x2 / y2 is preferably 0.1 or more and 5 or less, and more preferably 0.3 or more and 3 or less. x3 / y3 is preferably 2 or greater, more preferably 5 or greater, and even more preferably 10 or greater.

[0117] The intensity ratio of carbon to the first element in the first region obtained by the EELS analysis is x1: The intensity ratio of carbon and the first element in the second region is x2:y2, and the intensity ratio of carbon and the first element in the third region is x2:y2. The intensity ratio of carbon and the first element in the region is x3:y3. x1 / y1 is 0.3 or less. x2 / y2 is preferably 0.1 or more and 5 or less, and more preferably 0.3 or more and 3 or less. x3 / y3 is preferably 2 or more, more preferably 5 or more, and further preferably 10 or more.

[0118] In FIG. 54(A), the negative electrode is divided into a first region 551, a second region 552, and a third region 553. 54B, the second region 552 has a first region The material constituting the third region 553 may be a mixed region of the material constituting the third region 551. Here, for example, the first region 551 is a negative electrode active material, and the third region 553 is an electrolyte partition. The negative electrode active material contains a first element, for example, silicon. If the decomposition product of the electrolyte solution contains carbon, the first region 551 will have a carbon content in comparison to silicon. The third region 553 has a higher carbon content relative to silicon. That is, compared to x1 / y1, x3 / y3 has a larger value.

[0119] In addition, the negative electrode of one embodiment of the present invention has a S2p spectrum of 168 eV The spectral intensity in the vicinity is, for example, more than twice the spectral intensity in the vicinity of 163 eV, or More than three times, or even four times, more.

[0120] The current collectors of the positive and negative electrodes are made of stainless steel, gold, platinum, aluminum, titanium, etc. Materials with high electrical conductivity, such as metals and alloys thereof, can be used. When the current collector is used as a positive electrode, it is preferable that the current collector does not dissolve at the potential of the positive electrode. When used in the above, it is preferable that the material does not form an alloy with carrier ions such as lithium. Elements that improve heat resistance, such as silicon, titanium, neodymium, scandium, and molybdenum Aluminum alloys containing silicide can be used. The metal may be a metal element that reacts with silicon to form a silicide. The group elements are zirconium, titanium, hafnium, vanadium, niobium, tantalum, There are chromium, molybdenum, tungsten, cobalt, nickel, etc. The current collector is in foil or plate form. Shapes such as sheet, mesh, punched metal, and expanded metal are used as appropriate. It is preferable to use a current collector having a thickness of 5 μm or more and 30 μm or less.

[0121] 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.

[0122] 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 When MxO2 (M=Co, Al, etc.) is mixed, This is preferable because it is possible to improve the characteristics of a secondary battery using this.

[0123] 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 TEM (transmission electron microscope) or a laser diffraction / scattering method The specific surface area can be measured by a particle size distribution meter, etc. It can be determined.

[0124] 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.

[0125] 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:

[0126] 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 2.

[0127] As shown in FIG. 2(A), the crystal structure, crystal orientation, or oxygen content of the region is different. The lithium manganese composite oxide has a region 331, a region 332, and a region 333. Preferably, the region 332 contacts at least a part of the outside of the region 331. The region 333 is closer to the surface of the particle. It is preferred to have a region coincident with the surface of the grain that has a silicide.

[0128] As shown in FIG. 2B, 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. 2 and region 333.

[0129] Region 332 preferably has a different composition than region 331 .

[0130] 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 measured, for example, by EDX using a TEM. In some cases, it may be difficult to measure the lithium composition using the The difference in composition between region 331 and region 332 will be described with respect to elements other than lithium. Here, d 1 / (b1+c1) is preferably 2.2 or more, more preferably 2.3 or more, It is more preferable that d2 / (b2+c2) is less than 2.2. It is preferable that the ratio is less than 2.1, and more preferable that the ratio is 1.1 or more and 1.9 or less. Even in this case, the lithium ion including the region 331 and the region 332 is preferably The composition of the entire manganese-manganese composite oxide particle satisfies the above-mentioned 0.26≦(b+c) / d<0.5. It is preferable to add

[0131] 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.

[0132] 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.

[0133] 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.

[0134] 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 where the constant changes continuously or stepwise. Or, region 332 and region 331 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.

[0135] 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. .

[0136] 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.

[0137] 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.

[0138] The film thickness of the region 333 is preferably set to be not less than 0.4 nm and not more than 40 nm.

[0139] 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.

[0140] The positive electrode and the negative electrode may each contain a conductive additive. Examples of the conductive additive include carbon materials, Metal materials, conductive ceramic materials, etc. can be used. A fibrous material may be used. The content of the conductive assistant with respect to the total amount of the active material layer is 1 wt% or less. The content is preferably from 1 wt % to 10 wt %, and more preferably from 1 wt % to 5 wt %.

[0141] 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.

[0142] 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.

[0143] In addition, a graphene compound may be used as the conductive assistant.

[0144] 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, graphene or multi-graphene or reduced graphene It is particularly preferable to use RGO, which is, for example, an acid This refers to a compound obtained by reducing graphene oxide (GO). .

[0145] When using an active material with a small particle size, for example, 1 μm or less, the specific surface area of ​​the active material In such a case, the active material is required to have a large number of conductive paths. The use of a graphene compound that can efficiently form a conductive path even in a small amount is particularly advantageous. Preferred.

[0146] As an example, the following will describe a case where a graphene compound is used as a conductive assistant in an active material layer. An example of the surface configuration will be described.

[0147] 3A shows a vertical cross-sectional view of the active material layer. The active material layer is made of granular active material 103 and a conductive The graphene compound 321 as an auxiliary and a binder (not shown) are included. For example, graphene or multi-graphene may be used as the phene compound 321. Here, it is preferable that the graphene compound 321 has a sheet shape. The graphene compound 321 is a compound having a plurality of multi-graphenes or (and) a plurality of graphenes. The sheet may be partially overlapped to form a sheet.

[0148] In the vertical cross section of the active material layer, as shown in FIG. The sheet-like graphene compound 321 is uniformly dispersed. Compound 321 is shown in bold in schematic form, but in reality, the thickness of the single or multiple layers of carbon molecules is The graphene compound 321 wraps the active material particles 103. The active material 103 is formed so as to cover the active material 103 or to adhere to the surface of the active material 103. Therefore, they are in surface contact with each other.

[0149] 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.

[0150] Here, graphene oxide is used as the graphene compound 321, and is mixed with an active material to form an active material. It is preferable to form a layer to be a porous layer 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 active material layer. 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 active material layer 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.

[0151] 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 active material layer can be increased. This makes it possible to increase the discharge capacity of the power storage device.

[0152] The positive and negative electrodes may also contain a binder. For example, styrene-butadiene is used as the binder. Diene rubber (SBR), styrene-isoprene-styrene rubber, acrylonitrile-butadiene Rubber materials such as diene rubber, butadiene rubber, and ethylene-propylene-diene copolymer It is preferable to use fluororubber as the binder.

[0153] 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

[0154] Alternatively, the binder may be polystyrene, polymethyl acrylate, or polymethyl methacrylate. Polymethylmethacrylate (PMMA), Sodium polyacrylate, Polyvinyl alcohol (PVA), Poly Ethylene oxide (PEO), polypropylene oxide, polyimide, polyvinyl chloride, Polytetrafluoroethylene, polyethylene, polypropylene, polyisobutylene, poly Ethylene terephthalate, nylon, polyvinylidene fluoride (PVdF), polyacrylo Nitrile (PAN), Ethylene Propylene Diene Polymer, Polyvinyl Acetate, Nitrocel It is preferable to use a material such as loin.

[0155] The binder may be used in combination of two or more of the above.

[0156] 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.

[0157] 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.

[0158] 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. It is expected that the polymers will interact with each other and widely cover the surface of the active material.

[0159] 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.

[0160] [How to prepare electrodes] As an example of a method for producing the negative electrode and the positive electrode, a slurry is prepared and the slurry is applied. An example of a method for preparing a slurry used for preparing an electrode will be described below. Bell.

[0161] Here, the solvent used to prepare the slurry is preferably a polar solvent. For example, water , methanol, ethanol, acetone, tetrahydrofuran (THF), dimethylform Amides (DMF), N-methylpyrrolidone (NMP) and dimethylsulfoxide (DMS O) may be used alone or in a mixture of two or more thereof.

[0162] First, an active material, a conductive additive, and a binder are mixed to prepare a mixture A (step S1 10) Next, a solvent is added to mixture A, and the mixture is kneaded (mixed at high viscosity). The mixture B is prepared (step S120). Here, the mixture B is in a paste form, for example. It is preferable to add a second binder in the subsequent step S141. There may be a case where the first binder does not need to be added in step S110.

[0163] Next, a solvent is added to the mixture B, and the mixture is kneaded to prepare the mixture C (step S130 ).

[0164] Next, if a second binder is used, the second binder is added to prepare mixture D ( Step S141). At this time, a solvent may be added. Also, in the case where the second binder is not used, If necessary, a solvent is added to the mixture E to prepare a mixture E (step S142).

[0165] Next, for example, mixture D or mixture E prepared in a reduced pressure atmosphere is kneaded to prepare mixture F. (Step S150). At this time, a solvent may be added. In the mixing and kneading process of step S150, for example, a kneader can be used. .

[0166] Next, the viscosity of the mixture F is measured (step S160). By the above steps, a slurry for coating the active material layer is obtained. do.

[0167] Here, for example, in steps S130 to S160, mixtures C to The higher the viscosity of F, the better the dispersion of the active material, binder, and conductive additive in the mixture. Therefore, for example, the viscosity of mixture F is higher. On the other hand, if the viscosity of the mixture F is too high, for example, the coating speed of the electrode may become This may be undesirable from the viewpoint of productivity.

[0168] Next, a method for forming an active material layer on a current collector using the prepared slurry will be described. do.

[0169] First, the slurry is applied onto the current collector. Before applying the slurry, The surface may be subjected to a surface treatment. Examples of the surface treatment include a corona discharge treatment, a plasma treatment, Here, the undercoat treatment is a process in which a slurry is applied to the collector. Before coating, the active material layer is coated with a conductive material to reduce the interface resistance between the active material layer and the current collector and to prevent the interface resistance between the active material layer and the current collector from increasing. This refers to a film formed on the current collector to improve adhesion. Note that the term "undercoat" does not necessarily refer to a coating that is applied to the current collector. The undercoat does not have to be in the form of a film, and may be in the form of islands. The capacity can be expressed by using a carbon material as the undercoat. Examples of carbon materials include graphite, acetylene black, and ketjen black. (registered trademark), carbon black, carbon nanotubes, etc. can be used.

[0170] The slurry can be applied by the slot die method, gravure method, blade method, or a combination of these methods. A continuous coater or the like may be used for coating.

[0171] Next, the solvent of the slurry is volatilized, thereby forming the active material layer.

[0172] The solvent of the slurry is evaporated at a temperature of 50° C. to 200° C., preferably 60° C. to 150° C. It is recommended to carry out the process at a temperature range of 0.1 °C or less.

[0173] For example, heat the battery on a hot plate in an air atmosphere at 30°C to 70°C for 10 minutes or more. After the heat treatment, for example, the temperature is increased to 100°C and the temperature is increased to 1 hour or more and 10 hours or less. In this case, the heat treatment may be carried out in a reduced pressure environment.

[0174] Alternatively, the heat treatment may be performed using a drying oven or the like. When a drying oven is used, for example, Heat treatment may be performed at a temperature of 30° C. or higher and 120° C. or lower for 30 seconds or longer and 20 minutes or shorter.

[0175] Alternatively, the temperature may be increased stepwise. For example, heat treatment at 60°C or less for 10 minutes or less may be performed. After that, a further heat treatment may be carried out at a temperature of 65° C. or higher for 1 minute or more.

[0176] The thickness of the active material layer thus formed is preferably, for example, 5 μm to 300 μm. More preferably, the thickness is 10 μm or more and 150 μm or less. The mass loading is preferably, for example, 2 mg / cm 2 More than 50mg / cm 2 The following is acceptable.

[0177] The active material layer may be formed on both sides of the current collector, or on only one side. Alternatively, there may be regions where the active material layer is partially formed on both sides.

[0178] After the solvent is evaporated from the active material layer, the active material layer is compressed by a compression method such as a roll press method or a flat plate press method. Pressing may be performed. Heat may be applied during pressing.

[0179] The active material layer may be pre-doped. For example, but not limited to, the method may be electrochemical. For example, the method may be Using lithium metal as the counter electrode, lithium was propagated onto the active material layer in the electrolyte solution described below. Alternatively, a positive electrode for pre-doping can be prepared as a counter electrode for the negative electrode. The pre-doping may be performed by removing the positive electrode for pre-doping. By doing so, it is possible to suppress the decrease in charge / discharge efficiency, especially during the initial charging / discharging, and increase the capacity of the storage battery. Cut.

[0180] This embodiment mode can be implemented in appropriate combination with other embodiment modes.

[0181] (Embodiment 2) In this embodiment, a power storage device of one embodiment of the present invention will be described.

[0182] 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.

[0183] <Thin storage battery> FIG. 4 shows a thin storage battery as an example of a power storage device. If the structure has the above, when the device is mounted on an electronic device having at least a part having flexibility, This allows the battery to bend in accordance with the deformation of the electronic device.

[0184] FIG. 4 shows an external view of a storage battery 500, which is a thin storage battery. In addition, FIG. 5(A) and FIG. 4B shows a cross section taken along the line A1-A2 and a cross section taken along the line B1-B2 shown in FIG. 00 is a positive electrode 503 having a positive electrode current collector 501 and a positive electrode active material layer 502, and a negative electrode current collector 504 and a negative electrode 506 having a negative electrode active material layer 505, a separator 507, and an electrolyte 5 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 501 and the battery 6. The exterior body 509 contains an electrolyte 508. is filled with.

[0185] The electrolyte used in the electricity storage device is free of granular waste and elements other than the constituent elements of the electrolyte (hereinafter simply referred to as " It is preferable to use a highly purified electrolyte solution having a low content of impurities. Specifically, the weight ratio of impurities to the electrolyte is 1% or less, preferably 0.1% or less, more preferably 1% or less. It is preferably 0.01% or less.

[0186] 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.

[0187] Alternatively, a polymer gel electrolyte may be used in which a polymer is swollen with an electrolytic solution.

[0188] 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.

[0189] 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.

[0190] The separator 507 may be made of, 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.

[0191] 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. 6(A), the positive electrode 503 is sandwiched between the positive electrode 503 and the positive electrode 504. The separator 507 is folded in half as shown in FIG. 1, and the sealing portion 51 is formed on the outer side of the area overlapping with the positive electrode 503. By sealing with 4, the positive electrode 503 can be reliably supported within the separator 507. Then, as shown in FIG. 6(B), the positive electrode 503 and the negative electrode 505 wrapped in a separator 507 are 06 are alternately stacked and placed in an exterior body 509 to form a storage battery 500. It would be good to do so.

[0192] Next, aging after the storage battery is manufactured will be described. It is preferable to carry out aging. An example of the aging conditions is described below. The charging rate is between 0.001C and 0.2C. The temperature is, for example, above room temperature and 50 Here, if the reaction potential of the positive electrode or the negative electrode exceeds the range of the potential window of the electrolyte 508, In this case, the electrolyte may decompose due to charging and discharging of the battery. If gas is generated, it accumulates in the cell and the electrolyte comes into contact with the electrode surface. In other words, the effective reaction area of ​​the electrode is reduced, and the effective This corresponds to a higher resistance.

[0193] In addition, if the resistance becomes too high, the negative electrode potential will drop, causing lithium intercalation into the graphite. At the same time as the lithium penetration occurs, lithium deposition on the graphite surface also occurs. For example, after lithium is deposited, a film may grow on the surface, causing a decrease in the amount of lithium. If the lithium is removed, the lithium deposited on the surface cannot be re-eluted, and the amount of lithium that does not contribute to the capacity increases. In addition, if the deposited lithium physically collapses and loses electrical continuity with the electrode, However, lithium that does not contribute to the capacity is generated. Therefore, the potential of the negative electrode increases the charging voltage. It is preferable to degas the battery before it reaches the lithium potential by means of the pressure reduction method.

[0194] After degassing, the mixture is heated to a temperature higher than room temperature, preferably 30° C. to 60° C. More preferably, the temperature is 35° C. or higher and 50° C. or lower, for example, 1 hour or higher and 100 hours or lower. During the first charge, the electrolyte decomposed on the surface is transferred to the graphite surface. For example, by keeping the temperature higher than room temperature after degassing, In some cases, the formed coating may become dense.

[0195] FIG. 7 shows an example in which a current collector is welded to a lead electrode. As shown in FIG. 7(A), The positive electrode 503 wrapped in the current collector 507 and the negative electrode 506 are stacked alternately. 501 to a positive electrode lead electrode 510, and the negative electrode current collector 504 to a negative electrode lead electrode 511, An example of welding the positive electrode current collector 501 to the positive electrode lead electrode 510 is shown in FIG. The positive electrode current collector 501 is attached to the positive electrode lead electrode 510 at a welding area 512 by ultrasonic welding or the like. The positive electrode current collector 501 has a curved portion 513 as shown in FIG. This makes it possible to reduce stress caused by external force being applied to the storage battery 500 after it is manufactured. This can improve the reliability of the storage battery 500.

[0196] In the storage battery 500 shown in FIG. 4 and FIG. 5, the positive electrode lead electrode 510 has a positive electrode 503. The positive electrode current collector 501 is connected to the negative electrode lead electrode 511, and the negative electrode current collector 504 is connected to the negative electrode 506. The positive electrode serves as a terminal for electrical contact with the outside. The negative electrode current collector 501 and the negative electrode current collector 504 can also serve as the same. In that case, a lead electrode is not used. The positive electrode current collector 501 and the negative electrode current collector 504 are partially exposed to the outside from the exterior body 509. The components may be arranged so that

[0197] In addition, in FIG. 4, the positive electrode lead electrode 510 and the negative electrode lead electrode 511 are arranged on the same side. However, as shown in FIG. 8, the positive electrode lead electrode 510 and the negative electrode lead electrode 511 are arranged on 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 design freedom is high. In addition, the productivity of a product using the storage battery of one embodiment of the present invention can be improved. It can be improved.

[0198] In the storage battery 500, the exterior body 509 is made of, for example, polyethylene, polypropylene, Aluminium, steel, etc. are applied to a membrane made of a material such as polycarbonate, ionomer or polyamide. A thin metal film made of stainless steel, copper, nickel, or other material with excellent flexibility is applied, and then an exterior is applied to the thin metal film. The outer surface of the body is covered with an insulating synthetic resin film made of polyamide resin, polyester resin, etc. A layered film may be used.

[0199] In FIG. 5, as an example, the number of pairs of the positive electrode active material layers and the negative electrode active material layers facing each other 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.

[0200] [Pre-Dope] Here, an example of a case where pre-doping is performed on the negative electrode 506 of the storage battery 500 will be described. FIG. 9(A) shows the top surface of a laminate in which a positive electrode, a negative electrode, and a separator are laminated, and FIG. 9(B) shows the top surface of a laminate in which a positive electrode, a negative electrode, and a separator are laminated. A separator 507i is laminated on the negative electrode 506, and the separator 507 A positive electrode 503i for pre-doping is laminated on the positive electrode 503i, and a separator 507 is laminated on the positive electrode 503i. Then, the positive electrode 503 is laminated on the separator 507. The description of the positive electrode 503i can be referred to. The positive electrode 503i has a positive electrode active material layer 502i and a positive electrode current collector 501i. and the positive electrode current collector 501i are the positive electrode 503, the positive electrode active material layer 502, and the positive electrode current collector The description of the body 501 can be referred to. The positive electrode 503 and the positive electrode 503i are Different positive electrode active materials may be used.

[0201] Next, the laminate shown in FIGS. 9(A) and (B) is laminated as shown in the perspective view of FIG. 10(A). The sheet 509a is sandwiched between the sheet 509a, which serves as an outer casing.

[0202] Next, as shown in the top view of FIG. 10(B), three sides of the sheet 509a are sealed by heat or the like. Then, an exterior body 509 is formed, and the thin storage battery 500 is manufactured. FIG. 11A shows a cross-sectional view of the storage battery taken along dashed line B1-B2 shown in FIG.

[0203] Next, pre-doping is performed using the negative electrode 506 and the positive electrode 503i of the storage battery 500 thus fabricated. The pre-doping may be, for example, charging only, or charging and discharging.

[0204] After the pre-doping, one side of the exterior body 509 is cut and opened. As shown in the cross-sectional view of FIG. 5, the positive electrode 503i and the separator 503 are removed from the opened exterior body 509. At this time, take out separator 507, not separator 507i. Alternatively, the separator 507i may be left in the storage battery 500 without being removed.

[0205] Thereafter, as shown in the cross-sectional view of FIG. 11(C), the opened side of the exterior body 509 is sealed. Through the above steps, pre-doping can be carried out.

[0206] 9 to 11, a pair of a positive electrode active material layer and a negative electrode active material layer facing each other is shown. However, when pre-doping is performed, the positive electrode active material layer and the negative electrode active material layer do not have to be a single pair. FIG. 12 shows an example in which three pairs of positive and negative electrode active material layers face each other. In (A), the positive electrode 503i is disposed between the positive electrode 503 and the negative electrode 506 facing each other. First, pre-doping is performed using the positive electrode 503i and the negative electrode 506. Then, as shown in FIG. As shown in FIG. 12(C), the positive electrode 503i is removed, and the positive electrode active material layer and the negative electrode The battery has three sets of electrode active material layers facing each other.

[0207] In the above configuration, the exterior body 509 of the storage battery has a minimum curvature radius of, for example, 3 mm or more. 0 mm or less, and more preferably 3 mm to 10 mm. The exterior film of the secondary battery is made up of one or two sheets, forming a laminated structure. In the case of a battery, the cross-sectional structure of a curved battery is sandwiched between two curved films that are the exterior body. This results in a structure that is unique.

[0208] The radius of curvature of a surface will be described with reference to FIG. 13. In FIG. 13(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. 13B shows a top view of the curved surface 1700. FIG. 13C 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.

[0209] The secondary battery, which sandwiches electrodes and electrolyte (1805) between two films as the exterior body, is curved. In this case, the radius of curvature 1802 of the film 1801 on the side closer to the center of curvature 1800 of the secondary battery is smaller than the radius of curvature 1804 of the film 1803 on the side farther from the center of curvature 1800 ( FIG. 14(A). When a secondary battery is curved to have an arc-shaped cross section, the center of curvature is 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 14(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 secondary battery 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.

[0210] The cross-sectional shape of the secondary battery is not limited to a simple arc shape, and may be a shape that includes a partial arc. For example, the shape shown in FIG. 14(C), a wavy shape (FIG. 14(D)), an S-shape, etc. In the case where the curved surface of the secondary battery has a shape having a plurality of centers of curvature, Among the radii of curvature at each of the centers of curvature, the surface with the smallest radius of curvature is 2 For example, the minimum radius of curvature of the outer casing closest to the center of curvature of one outer casing is 3 mm or more and 30 mm or less. The deformation can be more preferably within the range of 3 mm to 10 mm.

[0211] Next, various examples of lamination of the positive electrode, the negative electrode and the separator are shown.

[0212] FIG. 17A 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.

[0213] In the configuration shown in FIG. 17(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.

[0214] Therefore, when the storage battery 500 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 bent, the exterior body 509 of the storage battery 500 is located on the inside of the bent portion. This refers to the radius of curvature of the surface that is in contact with the battery. Therefore, deterioration of the storage battery 500 can be suppressed. Moreover, the storage battery 500 can be made highly reliable.

[0215] FIG. 17(B) shows an example of lamination of a positive electrode 111 and a negative electrode 115 different from that shown in FIG. 17(A). In the configuration shown in FIG. 17(B), a positive electrode active material layer 122 is provided on both sides of a positive electrode current collector 121. As shown in FIG. 17(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, the capacity per unit volume of the storage battery 500 is The amount can be increased.

[0216] FIG. 17(C) shows an example of lamination of a positive electrode 111 and a negative electrode 115 different from that shown in FIG. 17(B). In the configuration shown in FIG. 17(C), a negative electrode active material layer 126 is provided on both sides of a negative electrode current collector 125. As shown in FIG. 17(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 per unit volume of the storage battery 500 is increased. The amount can be increased further.

[0217] In the configuration shown in FIG. 17, the separator 123 wraps the positive electrode 111 in a bag shape. However, the present invention is not limited to this. An example having a separator 123 with a different structure is shown. In the structure shown in FIG. 18(A), the positive electrode active A sheet-like separator 123 is provided between each of the material layers 122 and the negative electrode active material layers 126. The configuration shown in FIG. 18(A) differs from the configuration shown in FIG. Six layers of electrodes 111 and six layers of negative electrodes 115 are laminated, and six layers of separators 123 are provided.

[0218] FIG. 18B shows an example in which a separator 123 different from that in FIG. 18A is provided. In the configuration shown in FIG. 18(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. 18(B) is different from the structure shown in FIG. 18(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 must be folded at least five times. The negative electrode active material layer 126 is not only sandwiched between the negative electrode active material layers 126, but also extends to multiple positive electrodes 111. and the negative electrode 115 may be bound together.

[0219] Alternatively, the positive electrode, the negative electrode and the separator may be laminated as shown in FIG. FIG. 19(A) is a cross-sectional view of the first electrode assembly 130, and FIG. 19(B) is a cross-sectional view of the second electrode assembly 131. 19(C) is a cross-sectional view taken along dashed line A1-A2 in FIG. For clarity of illustration, the first electrode assembly 130, the second electrode assembly 131 and the separator An excerpt from data 123 is shown below.

[0220] As shown in FIG. 19(C), the storage battery 500 includes a plurality of first electrode assemblies 130 and a plurality of The electrode assembly 131 has a number of second electrode assemblies 131.

[0221] As shown in FIG. 19(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.

[0222] Further, as shown in FIG. 19(C), a plurality of first electrode assemblies 130 and a plurality of second The electrode assembly 131 is covered by a wound separator 123 .

[0223] [Coin-type battery] Next, as an example of the power storage device, an example of a coin-type storage battery will be described with reference to FIG. FIG. 15(A) is an external view of a coin-type (single-layer flat) storage battery, and FIG. 15(B) is , its cross-sectional view.

[0224] 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:

[0225] 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 .

[0226] The positive electrode 304 may be the same as that described for the positive electrode 503. The positive electrode active material layer 306 is For the negative electrode 307, see negative electrode 506. The layer 309 may be described with reference to the negative electrode active material layer 505. For the electrolyte, see the description of electrolyte 508.

[0227] 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.

[0228] 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 to each other.

[0229] The negative electrode 307, the positive electrode 304 and the separator 310 are impregnated with an electrolyte, and the negative electrode 307, the positive electrode 304 and the separator 310 are impregnated with an electrolyte. As shown in Fig. 2B, the positive electrode can 301 is placed downward, and the positive electrode 304, the separator 310, and the negative electrode 307 are placed in the same position. The positive electrode can 301 and the negative electrode can 302 are stacked in this order, and the positive electrode can 301 and the negative electrode can 302 are secured together with a gasket 303. The coin-shaped storage battery 300 is manufactured by crimping the wires through a wire cutout.

[0230] [Cylindrical storage battery] Next, a cylindrical storage battery will be shown as an example of a power storage device. The cylindrical storage battery 600 has a positive electrode on the upper surface as shown in FIG. It has a cap (battery cover) 601 and a battery can (outer can) 602 on the side and bottom. The positive electrode cap 601 and the battery can (outer can) 602 are connected with a gasket (insulating packing). The device is insulated by 610.

[0231] 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.

[0232] The positive electrode 604 may be referred to as the positive electrode 503. The negative electrode 606 may be referred to as the negative electrode 506. The positive electrode 604 and the negative electrode 606 may be formed by the method for preparing the electrodes shown in, for example, Embodiment 1. The positive and negative electrodes used in cylindrical storage batteries are wound, It is preferable to form an active material on both sides of the current collector. A negative electrode terminal (negative electrode current collecting lead) 607 is connected to the negative electrode 606. The positive electrode terminal 603 and the negative electrode terminal 607 are both made of a metal material such as aluminum. The positive terminal 603 is connected to a safety valve mechanism 612, and the negative terminal 607 is connected to a battery can 602. The safety valve mechanism 612 is a positive temperature coefficient (PTC) element. Temperature Coefficient) 611 via the positive electrode cap 601 The safety valve mechanism 612 is electrically connected to the battery when the internal pressure of the battery exceeds a predetermined threshold. In this case, the electrical connection between the positive electrode cap 601 and the positive electrode 604 is cut off. The PTC element 611 is a thermal resistance element whose resistance increases when the temperature increases. The PTC element is made of titanium oxide. Barium (BaTiO3) based semiconductor ceramics and the like can be used.

[0233] 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.

[0234] In this embodiment, the storage battery is a coin type, a cylindrical type, and a thin type. However, other types of batteries, such as sealed batteries and rectangular batteries, can be used. In addition, a structure in which a positive electrode, a negative electrode, and a separator are laminated in multiple layers, For example, other examples of the storage battery are shown in Figs. vinegar.

[0235] [Example of a thin storage battery configuration] 20 and 21 show an example of the configuration of a thin storage battery. The battery 3 has a negative electrode 994 , a positive electrode 995 , and a separator 996 .

[0236] The wound body 993 has a negative electrode 994 and a positive electrode 995 overlapped with a separator 996 sandwiched therebetween. The laminated sheet is then wound. The wound body 993 is placed in a rectangular sealed container or the like. A square secondary battery is produced by covering the battery with a material such as a plastic.

[0237] The number of layers of the negative electrode 994, the positive electrode 995, and the separator 996 may be as large as necessary. The negative electrode 994 is connected to the lead electrode 997 and the The positive electrode 995 is connected to a negative electrode collector (not shown) via one of the leads 998. The other of the electrode 997 and the lead electrode 998 is connected to a positive electrode collector (not shown). .

[0238] The storage battery 990 shown in FIG. 20(B) and FIG. 20(C) is a film 981 that serves as an exterior body. The film 982 having the recess is bonded to the film 982 by thermocompression or the like to form a space. The winding body 993 includes a lead electrode 997 and a lead The film 981 and the film 982 having the recesses are electrically connected to each other. It is impregnated with liquid.

[0239] The film 981 and the film 982 having the recesses are made of a metal material such as aluminum. The film 981 and the film 982 having the recesses can be made of a metal or resin material. If a resin material is used as the material for the recess 981, when an external force is applied, the recess 981 and the film 982 are The film 982 having the above structure can be deformed to produce a flexible storage battery. can be done.

[0240] In addition, although Fig. 20(B) and Fig. 20(C) show examples using two films, A space is formed by folding one sheet of film, and the above-mentioned wound body 9 is inserted into the space. 93 may also be accommodated.

[0241] In addition, the exterior body of the power storage device and the sealing container are made of a resin material, etc., so that the device has flexibility. However, when the exterior body or the sealing container is made of a resin material, The parts that are connected to the outside are made of conductive material.

[0242] For example, another example of a thin storage battery having flexibility is shown in FIG. 21. The wound body 9 in FIG. 93 is the same as that shown in FIG. 20(A), so detailed description will be omitted. .

[0243] The storage battery 990 shown in FIG. 21(B) and FIG. 21(C) has the above-described The winding body 993 includes a lead electrode 997 and a lead The electrode 998 is impregnated with an electrolyte inside the exterior bodies 991 and 992. The outer casing 992 can be made of a metal material such as aluminum or a resin material. If resin material is used as the material of 991 and 992, the exterior body 9 91, 992 can be deformed to produce a thin storage battery having flexibility. do.

[0244] By using an electrode including an active material according to one embodiment of the present invention in a flexible thin storage battery, This means that even if stress is applied to the electrodes by repeatedly bending a thin storage battery, the battery will remain active. This can prevent the material from being cleaved.

[0245] As a result, the active material having at least a part of the cleavage plane covered with graphene can be used for an electrode. As a result, it is possible to suppress a decrease in the battery voltage and a decrease in the discharge capacity. The cycle characteristics of the battery during charging and discharging can be improved.

[0246] [Example of energy storage system structure] A structural example of the power storage system will be described with reference to FIGS. The power system refers to, for example, a device equipped with a power storage device.

[0247] 22(A) and 22(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. 22(B), the power storage system has a terminal 951 and , a terminal 952 , an antenna 914 , and an antenna 915 .

[0248] 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.

[0249] 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.

[0250] 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.

[0251] 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.

[0252] The structure of the power storage system is not limited to the structure shown in FIG.

[0253] For example, as shown in Figs. 23(A-1) and 23(A-2), In the storage battery 913 shown in FIG. 22(B), an antenna is provided on each of a pair of opposing surfaces. FIG. 23(A-1) is an external view seen from one side of the pair of faces. FIG. 22(A-2) is an external view seen from the other side of the pair of surfaces. 22(A) and 22(B) are the same as those in the power storage system shown in FIG. The explanation of the energy storage system shown in 2(B) can be used as appropriate.

[0254] As shown in FIG. 23(A-1), a layer 916 is sandwiched between one of a pair of surfaces of a storage battery 913. As shown in FIG. 23(A-2), an antenna 914 is provided on one 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.

[0255] By adopting the above structure, the size of both antenna 914 and antenna 915 can be increased. It can be heard.

[0256] Or, as shown in FIG. 23(B-1) and FIG. 23(B-2), In the storage battery 913 shown in FIG. 22(B), a separate antenna is attached to each of a pair of opposing surfaces. FIG. 23(B-1) is an external view of the pair of surfaces as viewed from one side, FIG. 23(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. 22(A) and FIG. 22(B) are shown in FIG. The description of the power storage system shown in FIG. 22B can be used as appropriate.

[0257] As shown in FIG. 23(B-1), a layer 916 is sandwiched between one of the 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.

[0258] 24(A), the storage battery 91 shown in FIG. 22(A) and FIG. 22(B) 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. In addition, the same parts as those of the power storage system shown in FIG. 22(A) and FIG. 22(B) may be used. For this purpose, the description of the power storage system shown in FIG. 22(A) and FIG. 22(B) can be used as appropriate.

[0259] 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.

[0260] 24(B), the storage battery 91 shown in FIG. 22(A) and FIG. 22(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. 22(A) and FIG. 22(B) are used. For this, the explanation of the power storage system shown in FIG. 22(A) and FIG. 22(B) can be used as appropriate. Cut.

[0261] 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. .

[0262] 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.

[0263] This embodiment mode can be implemented in appropriate combination with other embodiment modes.

[0264] (Embodiment 3) In this embodiment, an example in which a flexible power storage device is mounted on an electronic device will be described. .

[0265] FIG. 25 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.

[0266] 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.

[0267] FIG. 25A 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.

[0268] FIG. 25B 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.

[0269] FIG. 25(D) 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. 25E 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.

[0270] FIG. 25(F) 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.

[0271] 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.

[0272] 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.

[0273] 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.

[0274] 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.

[0275] 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.

[0276] The display portion 7202 of the portable information terminal 7200 includes an electrode according to one embodiment of the present invention. For example, the power storage device 7104 shown in FIG. It can be installed in a curved state or in a curved state inside the band 7203. do.

[0277] 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.

[0278] FIG. 25G 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.

[0279] 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.

[0280] 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.

[0281] This embodiment mode can be implemented in appropriate combination with other embodiment modes.

[0282] (Embodiment 4) In this embodiment, an example of an electronic device in which a power storage device can be mounted will be described.

[0283] FIG. 26(A) and FIG. 26(B) show an example of a tablet terminal that can be folded in two. The tablet terminal 9600 shown in FIG. 26(A) and FIG. 26(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 26(A) shows the tablet terminal 9600 in an open state. 26(A) shows a state in which the tablet terminal 9600 is opened, and FIG. 26(B) shows a state in which the tablet terminal 9600 is closed.

[0284] 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.

[0285] 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.

[0286] 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.

[0287] In addition, the touch panel area 9632a and the touch panel area 9632b are simultaneously You can also use touch input.

[0288] 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.

[0289] FIG. 26A 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.

[0290] FIG. 26(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 of one embodiment of the present invention is used as the power storage unit 9635.

[0291] 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.

[0292] In addition, the tablet terminals shown in Fig. 26(A) and Fig. 26(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.

[0293] 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.

[0294] The configuration and operation of the charge / discharge control circuit 9634 shown in FIG. A block diagram is shown in FIG. 26C. 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.

[0295] 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.

[0296] 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.

[0297] Another example of electronic equipment is shown in FIG. 27. In FIG. 27, 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.

[0298] 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.

[0299] 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

[0300] In FIG. 27, 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.

[0301] In addition, FIG. 27 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.

[0302] 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.

[0303] In FIG. 27, 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.

[0304] In addition, Figure 27 shows a separate type air conditioner consisting of an indoor unit and an outdoor unit. 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.

[0305] In FIG. 27, 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 refrigerator door 8302, the freezer door 8303, the 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.

[0306] 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.

[0307] 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.

[0308] This embodiment mode can be implemented in appropriate combination with other embodiment modes.

[0309] (Embodiment 5) In this embodiment, an example in which a power storage device is mounted on a vehicle will be described.

[0310] 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.

[0311] 28A and 28B 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.

[0312] 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.

[0313] The automobile 8500 shown in FIG. 28B 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. 28(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.

[0314] 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.

[0315] 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.

[0316] This embodiment mode can be implemented in appropriate combination with other embodiment modes.

[0317] (Embodiment 6) 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 buffer control unit, see Figures 29 to 35. 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.

[0318] When multiple battery cells connected in series are repeatedly charged and discharged, In this case, variation occurs in the charge and discharge characteristics, and the capacity (output voltage) of each battery cell differs. In a series-connected battery cell, the total capacity during discharge is proportional to the capacity of the battery cell with the smallest capacity. If there is variation in the capacity of each battery cell, the overall capacity during discharge will be smaller. If charging is performed based on the battery cell with the smallest capacity, there is a risk of insufficient charging. If charging is performed based on the battery cell with the larger capacity, there is a risk of overcharging.

[0319] 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.

[0320] 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.

[0321] 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. .

[0322] Here, the CAAC-OS film will be described.

[0323] The CAAC-OS film is one of the oxide semiconductor films that has multiple crystal parts aligned along the c-axis. .

[0324] 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.

[0325] 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.

[0326] 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.

[0327] 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.

[0328] 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 2θ of around 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°.

[0329] 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. An element such as ZnO that has a stronger bond to oxygen than a metal element that constitutes an oxide semiconductor film is an oxide. 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.

[0330] 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.

[0331] 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.

[0332] 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.

[0333] 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 applied to such a battery cell in the power storage device includes the following: It is suitable to configure the semiconductor memory device using the OS transistor described above.

[0334] FIG. 29 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.

[0335] In addition, in the power storage device BT00 of FIG. 29, 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.

[0336] 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.

[0337] 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

[0338] 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.

[0339] The operation of the switching control circuit BT03 will now be described in detail.

[0340] 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.

[0341] 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.

[0342] 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.

[0343] Here, an example of the operation of the switching control circuit BT03 in this embodiment will be described with reference to FIG. FIG. 30 is a diagram for explaining an example of the operation of the switching control circuit BT03. For convenience of explanation, FIG. 30 shows an example in which four battery cells BT09 are connected in series. explain.

[0344] First, in the example of FIG. 30(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.

[0345] Next, the example of FIG. 30(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.

[0346] Finally, the example in FIG. 30(C) shows a case where the relationship is Va>Vb=Vc=Vd. That is, one high-voltage cell a and three consecutive low-voltage cells b to d are connected in series. In this case, the switching control circuit BT03 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:

[0347] The switching control circuit BT03 determines the results as shown in the examples of FIGS. 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.

[0348] The above is a detailed explanation of the operation of the switching control circuit BT03.

[0349] 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.

[0350] 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.

[0351] 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.

[0352] 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.

[0353] FIG. 31 and FIG. 32 are circuit diagrams showing configuration examples of the switching circuits BT04 and BT05. Shown in Figure 32.

[0354] In FIG. 31, 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

[0355] 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.

[0356] The switching circuit BT04 supplies a control signal S1 to the gates of the multiple transistors BT10. In response to the signal, 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.

[0357] 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.

[0358] In addition, in FIG. 31, 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.

[0359] 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.

[0360] 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. .

[0361] 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.

[0362] 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.

[0363] 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.

[0364] As an example, the switching circuit BT05 connects the charging battery cell group and the terminal pair BT Connect to 02.

[0365] 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.

[0366] 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.

[0367] 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 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.

[0368] In addition, the current control switch BT14 is not the switching circuit BT05 but the switching circuit B It may be included in T04.

[0369] FIG. 32 shows a configuration of the switching circuit BT04 and the switching circuit BT05, which is different from that shown in FIG. FIG.

[0370] In FIG. 32, 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 BT21 are connected to the two adjacent battery cells BT09. Among the multiple transistor pairs BT21, the transistor located at the most upstream The other end of the transistor pair BT21 is connected to the upstream end of the battery cell BT09 located at the most upstream of the battery unit BT08. The positive terminal of the transistor pair BT21 is connected to the positive terminal of the transistor pair BT22. The other end of the transistor pair BT21 is connected to the battery cell BT It is connected to the negative terminal of 09.

[0371] 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.

[0372] 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.

[0373] 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.

[0374] 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.

[0375] 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.

[0376] 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.

[0377] 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.

[0378] 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

[0379] 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.

[0380] 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).

[0381] Here, an example of the operation of the transformer control circuit BT06 in this embodiment will be described with reference to FIGS. 33(A) to (C) are diagrams showing the radiation pattern described in FIG. 30(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. 33(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.

[0382] In the example shown in FIG. 33(A), three consecutive high voltages are generated as described in FIG. 30(A). 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).

[0383] 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.

[0384] 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

[0385] In the example shown in FIG. 33(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.

[0386] In the examples shown in FIG. 33(B) and FIG. 33(C), the conversion ratio is the same as in FIG. 33(A). In the examples shown in FIG. 33(B) and FIG. 33(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.

[0387] 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.

[0388] 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.

[0389] 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.

[0390] The configuration of the transformer circuit BT07 using an isolated DC-DC converter is shown in Figure 34. 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.

[0391] The flow of processing by the power storage device BT00 in this embodiment will be described with reference to FIG. 5 is a flowchart showing the flow of processing by the power storage device BT00.

[0392] 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.

[0393] In addition, in the flowchart of FIG. 35, multiple steps are described in order, but each step The order in which the steps are performed is not limited to the order listed.

[0394] 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.

[0395] Furthermore, the number of battery cells BT09 included in the discharge battery cell group is and the number of battery cells BT09 included in the charging battery cell group, The applied discharge voltage is converted to a charge voltage and applied to the terminal pair BT02. Regardless of the selection of the battery cell BT09 on the power supply side and the charging side, the charge transfer can be performed without any problem. It can be realized.

[0396] 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.

[0397] This embodiment mode can be implemented in appropriate combination with other embodiment modes. EXAMPLES

[0398] In this example, CV (cyclic voltammetry) measurement of the electrolyte was carried out.

[0399] Four types of electrolytes, electrolyte A-1, electrolyte A-2, electrolyte A-3 and electrolyte A-4, were prepared. All four electrolytes were prepared using EMI-FSA (1-ethyl-3-methylimide) as a solvent. Electrolyte A-2 and Electrolyte A-3 were used. In electrolyte A-4, LiFSA (lithium bis(fluorosulfonyl)acetate) was used as the electrolyte. The electrolyte A-1 did not contain any electrolyte. The concentration of electrolyte A-2 is 1 mol / L, and that of electrolyte A-3 is 0.1 mol / L. , and was 0.01 mol / L in electrolyte A-4.

[0400] The reference electrode was lithium, the working electrode was copper, and the counter electrode was platinum. The area of ​​the working electrode was 0.02c m 2 The electrolyte for the reference electrode was PP13-TFSA (N-methyl-N- Propyl piperidinium bis(trifluoromethanesulfonyl)amide) was used as an electrolyte. LiTFSA (lithium bis(trifluoromethanesulfonyl)amide) was used as the The electrolyte concentration in the electrolytic solution was set to 0.4 mol / L.

[0401] The scan rate was 50 mV / sec. and the voltage range was 3 V to -0.5 V. Electrolyte A The CV measurement results for electrolytes A-1, A-2, A-3 and A-4 are shown in Figure 36(A). (B), as shown in Figures 37(A) and (B). The horizontal axis is Li / Li + The vertical axis shows the potential relative to indicates the current density.

[0402] In electrolyte A-1, which does not contain lithium salt, a reduction current was observed at about 0.7 V, and EM This suggests a reduction reaction of I-FSA. In electrolyte A-2, the 0.7% ion concentration was lower than that in electrolyte A-1. The reduction current near V was suppressed, and the reduction current and oxidation current near 0 V were observed, It was suggested that this corresponds to the deposition and dissolution of lithium. In electrolyte A-2, Lithium ions form an electric double layer on the surface of the electrode, and EMI cations and FS It is believed that the reduction reaction of either or both of the A anions could be suppressed.

[0403] In electrolyte A-3, no significant reduction current was observed up to around 0 V, indicating that the decomposition of EMI was suppressed. However, no oxidation current was observed, which would suggest the deposition of lithium. In solution A-4, a reduction current was observed at potentials higher than 0 V, and the reduction current was observed for the EMI cation and FS It was suggested that reduction reactions of either or both of the A anions occurred.

[0404] Figure 38 (A) and (B) show the second and third cycles in electrolyte A-4. The CV measurement results for the second and third cycles are shown in Fig. 1. The results were almost the same as those of the CV measurement waveform of electrolyte A-1 without salt. In this case, the concentration of lithium salt is low, and the electric double layer cannot be sufficiently formed on the surface of the electrode, resulting in E It is believed that the concentration of lithium salt is insufficient to suppress the reduction reaction of the MI cation, etc. do.

[0405] In addition, in electrolyte A-4, the sweep rate was set to 0.5 mV / sec. and the voltage range was set to 3 V. It was found that the reduction reaction was suppressed by performing CV measurements at a potential of -0.3 V from The results are shown in Figure 39.

[0406] Next, electrolytic solution A-5 and electrolytic solution A-6 were prepared. In this study, EMI-TFSA was used as the solvent and LiTFSA was used as the electrolyte. The electrolyte concentration in the solution was 1 mol / L for electrolyte A-5 and 1 mol / L for electrolyte A-6. The concentration was set at 2 mol / L.

[0407] In Figure 40, the sweep speed is 0.5mV / s and the voltage range is 3V to - 0.15V, and in FIG. 41(A), the sweep speed is 0.5 mV / s in electrolyte A-6. The range is from 3 V to 0 V, and in Figure 41(B), the sweep speed is 0.1 mV / The results are shown for a range of voltages from 3 V to 0 V. The lithium salt concentration was 2 mol / In the electrolyte A-6 with 0.1% solubility, a peak indicating the dissolution of lithium was observed and It is possible that the electric double layer suppressed the reduction reaction of EMI cations, etc. EXAMPLES

[0408] In this example, a storage battery was produced and the charge / discharge cycle was measured.

[0409] First, electrolyte solution A-7 and electrolyte solution AC-1 were prepared. In electrolyte solution A-7, B was used as a solvent. MI-FSA was used, and LiFSA was used as the electrolyte. The concentration of the electrolyte in the electrolyte solution was 1 The comparative electrolyte, electrolyte AC-1, contained EC and DEC as solvents. The solvent was a mixture of EC:DEC = 3:7 by volume, and LiPF6 was used as the electrolyte. The electrolyte concentration in the electrolytic solution was 1 mol / L.

[0410] [Preparation of electrodes] Next, a negative electrode E1, a positive electrode E2, and a positive electrode E3 were prepared.

[0411] The composition and preparation method of the negative electrode E1 will be described. The active material is carbon-coated Si O was used, polyimide was used as a binder, and acetylene black was used as a conductive additive. The composition of the slurry for preparing the electrodes is SiO: acetylene black: polyimide = The ratio was 80:5:15 (by weight).

[0412] First, acetylene black and the solvent NMP were mixed using a mixer to produce the first mixture. A compound was obtained.

[0413] Next, an active material was added to the first mixture to obtain a second mixture.

[0414] Next, the NMP solution of polyimide was added to the second mixture, and the mixture was kneaded using a kneader. A slurry was prepared according to the above process.

[0415] Next, the prepared slurry was applied to one side of a 10 μm-thick stainless steel current collector. A continuous coater was used for coating, and the coating speed was 0.15 m / min. Then, a drying oven was used. The drying conditions were 40°C and 20 minutes.

[0416] Next, the prepared electrode was heat-treated to convert it into imidation. A muffle furnace was used for the heat treatment. The heat treatment was carried out in a nitrogen atmosphere at 400°C for 5 hours. It was made.

[0417] Next, positive electrodes E2 and E3 were prepared.

[0418] The composition and preparation conditions of the positive electrode E2 are explained. The active material is Li with an average particle diameter of 10 μm. CoO2 is used, PVdF is used as a binder, and acetylene black is used as a conductive additive. The composition of the slurry for preparing the electrode was LiCoO2: acetylene black: P The VdF ratio was 90:5:5 (wt%).

[0419] The active material, the binder, and the conductive additive were mixed to prepare a slurry. The solution was applied to one side of an aluminum current collector with a thickness of 20 μm. The solvent was then evaporated. The active material layer was pressed. Through the above steps, a positive electrode E2 was produced.

[0420] The composition and preparation conditions of the positive electrode E3 are explained below. The active material has a specific surface area of ​​15.6 m 2 / g LiFePO4 is used, PVdF is used as a binder, and acetylene black is used as a conductive additive. The slurry used to prepare the electrode was formulated as follows: LiFePO4: acetylene bromide The ratio of lac:PVdF was 85:8:7 (wt %).

[0421] First, acetylene black and PVdF, which is a binder, are mixed in a mixer. A mixture of the following was obtained:

[0422] Next, an active material was added to the first mixture to obtain a second mixture.

[0423] Next, NMP, a solvent, was added to the second mixture, and the mixture was kneaded using a kneader. A slurry was produced by this process.

[0424] Next, the mixture was mixed in a large mixer.

[0425] Next, the prepared slurry was applied to a 20 μm-thick aluminum alloy that had previously been undercoated. The coating was applied to one side of the current collector using a continuous coater at a coating speed of 0.2 m / min. The solvent was then evaporated in a drying oven. The drying oven conditions were 70°C for 7.5 minutes. This was followed by a treatment at 90°C for 7.5 minutes.

[0426] Next, the positive electrode active material layer was pressed by a roll press method to compact it. Thus, a positive electrode E3 was prepared.

[0427] [Making a storage battery] Next, the negative electrode E1, the positive electrode E2, and the positive electrode E3 are cut, and lead electrodes are attached to the tab regions. The negative electrode E1 had an area of ​​23.8 cm 2 , the area of ​​positive electrode E2 and positive electrode E3 is 20.5 cm 2 It was decided.

[0428] Next, the negative electrode E1 and the positive electrode E2 are arranged to face each other with the first separator interposed therebetween, and further A second separator was then placed on the positive electrode E2, and a positive electrode E3 was then placed on the second separator. Between the positive electrode E3 and the negative electrode E1, a second separator, a positive electrode E2 and a first separator are arranged. The TF40 manufactured by Lurose was used.

[0429] The sheet used to form the exterior body is an aluminum sheet coated with resin on both sides. A laminate of a negative electrode E1, a first separator, a positive electrode E2, a second separator, and a positive A laminate consisting of pole E3 was wrapped in the sheet folded in half.

[0430] Next, two of the three sides of the folded sheet are sealed by heat to form an exterior body. The ends of the lead electrodes attached to each electrode were positioned on the outside of the sheet. Then, it was dried at 80°C.

[0431] Next, in a reduced pressure atmosphere of -60 kPa or less, electrolytic The amount of electrolyte injected was about 0.6 ml. The battery BA and the comparative battery using the comparative electrolyte AC-1 are designated as battery BC.

[0432] The loading amount of the negative electrode E1, the positive electrode E2, and the positive electrode E3 used in the storage battery BA was 2.0 mg / cm 2 , 20mg / cm 2 , and 9.3 mg / cm 2 The density was 0.55g / cm c, approximately 2.2 g / cc and 1.0 g / cc.

[0433] The loading amount of the negative electrode E1, the positive electrode E2, and the positive electrode E3 used in the storage battery BC was 2.0 mg / cm 2 , 20mg / cm 2 and 9.4 mg / cm 2 The density was 0.63g / cc. , 2.1g / cc and 1.1g / cc. Here, the loading amount is the amount per unit area. This refers to the weight of active material.

[0434] Next, the unsealed side was sealed by heat. A storage battery was produced by the above steps. .

[0435] [Pre-Dope] At 25°C, constant current charging was performed using the positive electrode E2 as the positive electrode and the negative electrode E1 as the negative electrode. The charging conditions were a current density of 17.9 mA / g (corresponding to approximately 0.01 C relative to the capacity of the negative electrode active material). The battery was charged to 600mAh / g with a constant current (Vpn) of 1000mAh / g. After charging, a rest period of 0.5 hours was allowed.

[0436] After charging, one side of the exterior body was cut. Then, the positive electrode E2 and The second separator was removed.

[0437] Next, electrolyte A-7 was added to battery BA, and electrolyte AC-1 was added to battery BC. .3ml was injected.

[0438] The cut and opened side was then sealed by heat.

[0439] [aging] Next, an aging process was performed. First, the positive electrode was treated with the positive electrode E3 and the negative electrode was treated with the negative electrode E4 at 25°C. The charging conditions were a current density of 1.7 mA / g (positive electrode active material volume) and The maximum voltage was set to 3.2 V. The rest time after charging was set to 1.0 V. It was set for two hours.

[0440] After charging, one side of the exterior body was cut to release the gas. The sides were sealed by heat.

[0441] Next, the current density was set to 8.5 mA / g (equivalent to approximately 0.05 C) and the upper voltage limit was set to 4 V. The battery was charged with a current of 34mA / g (equivalent to approximately 0.2C) and the lower limit voltage was The constant current discharge was performed at 2 V. After charging and discharging, the rest time was set to 2 hours. I did.

[0442] Next, the current density was set to 34 mA / g, and constant current charging and discharging was performed for two cycles. The charge and discharge curves of the battery are shown in Figure 42. The solid line in the figure shows the first charge and discharge, and the dotted line shows the second charge and discharge. Figure 42(A) shows the charge and discharge cycles of battery BC, and Figure 42(B) shows the charge and discharge cycles of battery BA. The upper limit of the charge voltage was set to 4 V, and the lower limit of the discharge voltage was set to 2 V. After charging and discharging, A rest period of 2 hours was set for each step. The above steps were used as the aging process.

[0443] [Charge / discharge cycle] The charge-discharge cycle characteristics of the storage batteries BA and BC that were subjected to the aging process were The charge and discharge were performed at a constant current density of 51 mA / g (equivalent to approximately 0.3 C). The upper limit of the charge voltage was 4 V, and the lower limit of the discharge voltage was 2 V. After charging and discharging, The rest period was 0.5 hours. Figure 43 shows the charge / discharge cycle characteristics. The vertical axis indicates the number of cycles, and the vertical axis indicates the discharge capacity. For battery BC, the discharge capacity at 500 cycles The capacity of the battery BA decreased to about 60% of the initial discharge capacity after 500 cycles. The discharge capacity at the first charge / discharge cycle was more than 80% of the initial discharge capacity, demonstrating excellent charge / discharge cycle characteristics. I realized that. EXAMPLES

[0444] The storage batteries BA and BC prepared in Example 2 were charged and discharged. The surface of the negative electrode was subjected to XPS analysis.

[0445] After the charge-discharge cycle, the storage batteries BA and BC were disassembled. After disassembly, deuterium replacement was performed. Acetonitrile was added and mixed with the electrolyte remaining in the battery, and the mixture was extracted with a pipette. After that, the negative electrode was immersed in DMC in a petri dish and washed. The DMC was replaced twice, and the total The substrate was washed three times, and then the solvent was evaporated in a reduced pressure atmosphere.

[0446] Next, XPS analysis was performed on the negative electrodes of the batteries BA and BC. The percentages (atomic %) of F, S, Li, P, N, Al and Si are shown in Table 1.

[0447] [Table 1]

[0448] Figure 44(A) shows C1s, Figure 44(B) shows O1s, Figure 45(A) shows F1s, Figure 45 (B) shows the spectrum of S2p, and Figure 46 shows the spectrum of Li1s.

[0449] A significant difference was observed in the peak of S2p. The Ox peak was more than three times larger than the metal-S peak. EXAMPLES

[0450] The storage batteries BA and BC prepared in Example 2 were charged and discharged. The cross section of the negative electrode was observed.

[0451] After the charge-discharge cycle, the storage batteries BA and BC were disassembled. After disassembly, deuterium replacement was performed. Acetonitrile was added and mixed with the electrolyte remaining in the battery, and the mixture was extracted with a pipette. After that, the negative electrode was immersed in DMC in a petri dish and washed. The DMC was replaced twice, and the total The substrate was washed three times, and then the solvent was evaporated in a reduced pressure atmosphere.

[0452] Next, in order to observe the cross section of the negative electrode, a thin section was made using FIB. The cross section of the negative electrode was observed using a sintered body. Observation results of the negative electrodes of storage batteries BC and BA is shown in Figures 47 and 48.

[0453] Next, the cross section of the negative electrode was observed by STEM, and STEM-EDX line analysis was performed for elemental analysis. A total of six elements were analyzed: carbon, oxygen, fluorine, silicon, phosphorus and sulfur. For the storage battery BC, the STEM image of the area where the line analysis was performed is shown in Figure 49(A), and the obtained line The spectra of the analysis are shown in FIG. 49(B) and FIG. 51(A). For the storage battery BA, the line segment The STEM image of the area where the analysis was performed is shown in Figure 50(A), and the spectrum of the obtained line analysis is shown in Figure 50(B). The vertical axis of Fig. 49(B) and Fig. 50(B) is the signal strength. The vertical axis in Figure 51(A) and Figure 51(B) indicates the abundance ratio of each element in units of is shown as atomic%.

[0454] In FIG. 49(B) and FIG. 51(A), the region from the surface to about 0.2 μm is the third The region from about 0.2 μm to about 0.45 μm is the second region. The region deeper than 0.45 μm is defined as the first region. The first region is mainly It is believed that the SiO component, which is the negative electrode active material, is detected in the third region. It is believed that the components of the film formed by the decomposition of the electrolyte were detected. This is considered to be a mixed region of the negative electrode active material and the coating. In the results, the intensity of carbon in the third region is more than 10 times that of silicon. In contrast, in the second region it is approximately one time and in the first region it is less than one-sixth. In the EDX analysis results shown in FIG. 51(A), the number of carbon atoms in the third region is The number of atoms in the first region is about 4 times that of the first region, while the number of atoms in the second region is about 20 times that of the first region. In the region, it is about 1x.

[0455] In FIG. 50(B) and FIG. 51(B), the region from the surface to about 0.1 μm is the third The region from about 0.1 μm to about 0.2 μm is the second region. The region deeper than 0.2 μm is defined as the first region. The analysis results showed that the intensity of carbon in the third region was more than 10 times that of silicon, and In the second region, it is about 1x, and in the first region, it is less than 1 / 6. In the EDX analysis results shown in (B), the number of carbon atoms in the third region is 1 / 2 the number of silicon atoms. In the first region, the difference is more than 20 times, whereas in the second region, it is about 3 times and in the first region, In some cases, it is approximately 1x.

[0456] Next, EELS line analysis was performed as an elemental analysis. Line analysis was performed on the storage battery BC. The SEM image of the area is shown in FIG. 52(A), and the obtained line analysis spectrum is shown in FIG. 52(B). For the storage battery BA, the SEM image of the area where the line analysis was performed is shown in FIG. The spectrum of the analysis is shown in Figure 53(B), where the vertical axis indicates signal intensity.

[0457] In FIG. 52(B), the region from the surface to about 0.2 μm is defined as the third region. The region from about 0.2 μm to about 0.45 μm is defined as the second region. The region deeper than about 1 μm is defined as the first region. In the third region, the carbon intensity is more than 10 times that of silicon, In the second region, it is about half, and in the first region, it is less than one-tenth.

[0458] In FIG. 53(B), the region from the surface to about 0.1 μm is defined as the third region. The region from about 0.1 μm to about 0.2 μm is defined as the second region. The region deeper than the vicinity is defined as the first region. The intensity of carbon in the third region is more than 10 times that of silicon, and in the first region, is approximately one-tenth or less.

[0459] 47 to 53, the negative electrode of the storage battery BA is in the second region compared to the negative electrode of the storage battery BC. It was suggested that the thin thickness would suppress cracks and pulverization on the surface of the active material. [Explanation of symbols]

[0460] 103 Active material 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 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 501i positive electrode current collector 502 Positive electrode active material layer 502i positive electrode active material layer 503 Positive electrode 503i positive electrode 504 Negative electrode current collector 505 Negative electrode active material layer 506 negative electrode 507 Separator 507i Separator 508 Electrolyte 509 Exterior body 551 First Area 552 Second Area 553 The Third Region 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 671 Negative electrode active material 681 Cation 681b Precipitated layer 682 Cation 683 Anions 684 Reactants 685 Coating 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 981 Film 982 Film 990 Battery 991 Exterior body 992 Exterior body 993 Wound body 994 negative electrode 995 positive electrode 996 Separator 997 Lead Electrode 998 Lead Electrode 1700 curved surface 1701 Plane 1702 Curve 1703 Radius of curvature 1704 Center of curvature 1800 Center of curvature 1801 Film 1802 radius of curvature 1803 Film 1804 Radius of curvature 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. The battery has a positive electrode, a negative electrode, and an electrolyte solution, The negative electrode has a negative electrode active material which is SiO coated with carbon and a conductive assistant, The negative electrode has a first region, a second region in contact with a surface of the first region, and a third region in contact with a surface of the second region, The electrolyte comprises 1-ethyl-3-methylimidazolium (fluorosulfonyl)amide, the third region is a region extending from the surface to a depth of 0.2 μm, the second region is a region from 0.2 μm to 0.45 μm; the first region is a region deeper than 0.45 μm; In the line analysis of EELS, the third region has a carbon strength that is 10 times or more greater than a silicon strength; the second region has a carbon intensity lower than a silicon intensity; A lithium ion secondary battery, wherein the strength of carbon in the first region is 1 / 10 or less than the strength of silicon.

2. In claim 1, The negative electrode is a lithium ion secondary battery, in which a spectral intensity near 168 eV in an S2p spectrum of an XPS analysis is at least twice as high as a spectral intensity near 163 eV.

3. In claim 1 or 2, A lithium-ion secondary battery that was charged with an upper limit voltage of 3.2 V and then aged with a rest period of 2 hours.

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