Battery storage systems and battery storage system operator vehicles

Abstract

To provide a storage battery that is influenced less easily by environmental temperature, and a storage battery that can be charged and discharged even in the low-temperature environment.SOLUTION: A storage battery includes a secondary battery that can be charged and discharged even at low temperature and a general secondary battery, which are provided adjacent to each other. The storage battery with such a structure can use heat, which is generated as the secondary battery that can be charged and discharged even at low temperature in the low-temperature environment is charged and discharged, as an internal heat source. Specifically, the storage battery includes a first lithium ion secondary battery and a second lithium ion secondary battery that are provided adjacent to each other. The first lithium ion secondary battery includes at least one of ion liquid, a molecular crystal electrolyte, a semi-solid electrolyte, an all-solid electrolyte, and lithium titanate. The second lithium ion secondary includes an organic electrolyte solution.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This relates to storage batteries and methods for manufacturing them, or to vehicles, etc., that have storage batteries.

[0002] One aspect of the present invention relates to a product, a method, or a method of manufacture; or to a process, a machine, a manufacture, or a composition of matter. Another aspect of the present invention relates to a semiconductor device, a display device, a light-emitting device, a power storage device, a lighting device, an electronic device, or a method of manufacturing the same.

[0003] In this specification, "electronic equipment" refers to all devices that have an energy storage device, and all electro-optical devices with an energy storage device, information terminal devices with an energy storage device, etc., are considered electronic equipment.

[0004] In this specification, the term "energy storage device" refers to all elements and devices that have an energy storage function. For example, this includes energy storage devices such as lithium-ion secondary batteries (also called secondary batteries), lithium-ion capacitors, and electric double-layer capacitors. [Background technology]

[0005] In recent years, there has been a great deal of development on various energy storage devices, including lithium-ion secondary batteries, lithium-ion capacitors, and air batteries. In particular, lithium-ion secondary batteries, with their high output and high energy density, are seeing rapidly expanding demand in conjunction with the development of the semiconductor industry. They are used in mobile information terminals such as mobile phones, smartphones, and notebook computers, as well as portable music players, digital cameras, medical equipment, and next-generation clean energy vehicles such as hybrid vehicles (HV), electric vehicles (EV), and plug-in hybrid vehicles (PHV). As a rechargeable energy source, they have become indispensable to today's information society.

[0006] However, conventional lithium-ion secondary batteries have problems with charging and discharging at low or high temperatures. In particular, at sub-zero temperatures, secondary batteries containing organic solvents experience an increase in the viscosity of the organic solvent, resulting in insufficient charging and discharging characteristics. However, since it is desirable for secondary batteries to exhibit stable performance regardless of the environment, measures such as installing a heater around the secondary battery have been taken (for example, Patent Document 1). [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 08-138762 [Non-patent literature]

[0008] [Non-Patent Document 1] Shannon et al., Acta A 32 (1976) 751. [Overview of the project] [Problems that the invention aims to solve]

[0009] However, adding an external heat source such as a heater increases costs and raises the risk of failure. Therefore, one aspect of the present invention aims to provide a rechargeable battery that can regulate the temperature of a secondary battery without using an external heat source such as a heater, and that can exhibit stable performance regardless of the environment. Another aspect of the present invention is to provide a rechargeable battery with high safety.

[0010] Furthermore, one aspect of the present invention aims to provide a method for producing these.

[0011] Furthermore, the description of these problems does not preclude the existence of other problems. Moreover, one aspect of the present invention does not need to solve all of these problems. It is possible to extract other problems from the description, drawings, and claims. [Means for solving the problem]

[0012] To solve the above problems, one aspect of the present invention provides a storage battery in which a secondary battery capable of charging and discharging even at low temperatures and a general secondary battery are placed adjacent to each other. In a storage battery with such a configuration, the heat generated by the charging and discharging of the secondary battery capable of charging and discharging even at low temperatures can be used as an internal heat source in a low-temperature environment.

[0013] One aspect of the present invention is a storage battery comprising a first lithium-ion secondary battery and a second lithium-ion secondary battery adjacent to each other, wherein the first lithium-ion secondary battery has at least one of an ionic liquid, a molecular crystalline electrolyte, a semi-solid electrolyte, a fully solid electrolyte, and lithium titanate, and the second lithium-ion secondary battery has an organic electrolyte.

[0014] In the above, the storage battery further includes a temperature sensor and a control circuit, the first lithium-ion secondary battery has a first temperature range as its operating temperature range, the second lithium-ion secondary battery has a second temperature range that includes the upper limit of the first temperature range as its operating temperature range, the lower limit of the first temperature range is lower than the lower limit of the second temperature range, the temperature sensor has the function of detecting the temperature of the second lithium-ion secondary battery, and the control circuit may have the function of heating the first lithium-ion secondary battery by self-heating when the temperature of the temperature sensor is lower than the second temperature range, thereby bringing the temperature of the second lithium-ion secondary battery within the second temperature range.

[0015] Furthermore, it is preferable that the first lithium-ion secondary battery has the function of a residual heat source, and the second lithium-ion secondary battery has the function of starting to discharge to the outside after the temperature has been brought within the second temperature range.

[0016] Furthermore, in the above, it is preferable that the number of first lithium-ion secondary batteries is less than the number of second lithium-ion secondary batteries.

[0017] Furthermore, in the above configuration, it is preferable that the first lithium-ion secondary battery and the second lithium-ion secondary battery are substantially rectangular parallelepipeds, and that their largest surfaces face each other.

[0018] Furthermore, in the above configuration, it is preferable to have a material with a higher thermal conductivity than air between the first lithium-ion secondary battery and the second lithium-ion secondary battery.

[0019] Furthermore, in the above, it is preferable that the first lithium-ion secondary battery and the second lithium-ion secondary battery are substantially cylindrical in shape, and that there be a material with a higher thermal conductivity than air between the first lithium-ion secondary battery and the second lithium-ion secondary battery.

[0020] Furthermore, in the above, it is preferable that the storage battery has a plurality of first lithium-ion secondary batteries and an inverter, and that the control circuit has the function of converting the discharge current of one of the first lithium-ion secondary batteries into an alternating current using the inverter when the temperature of the temperature sensor is lower than the second temperature range, and repeatedly charging and discharging another first lithium-ion secondary battery using the alternating current.

[0021] Furthermore, it is preferable that the control circuit has a function to detect at least one of overcharging, over-discharging, or overcurrent, and to protect the first lithium-ion secondary battery and the second lithium-ion secondary battery.

[0022] Furthermore, in the above, it is preferable that the first lithium-ion secondary battery has an ionic liquid and an organic electrolyte.

[0023] Another aspect of the present invention is a vehicle having the storage battery described above. [Effects of the Invention]

[0024] According to one aspect of the present invention, it is possible to provide a rechargeable battery that can regulate the temperature of a secondary battery without providing an external heat source, and that can exhibit stable performance regardless of the environment. Furthermore, it is possible to provide a rechargeable battery that reduces costs. Furthermore, it is possible to provide a rechargeable battery with a reduced risk of failure. Furthermore, it is possible to provide a rechargeable battery with high safety.

[0025] Furthermore, according to one aspect of the present invention, a method for producing these can be provided.

[0026] Furthermore, the description of these effects does not preclude the existence of other effects. Moreover, one aspect of the present invention does not necessarily have to possess all of these effects. Other effects will naturally become apparent from the description in the specification, drawings, and claims, and it is possible to extract other effects from the description in the specification, drawings, and claims. [Brief explanation of the drawing]

[0027] [Figure 1] Figures 1(A) through 1(E) illustrate the storage battery. [Figure 2] Figures 2(A) and 2(B) illustrate the storage battery. [Figure 3] Figures 3(A) through 3(D) illustrate the storage battery. [Figure 4] Figures 4(A) through 4(C) illustrate the storage battery. [Figure 5] Figures 5(A) and 5(B) illustrate the storage battery. [Figure 6] Figures 6(A) and 6(B) are perspective views of the secondary battery, and Figure 6(C) is a perspective view of the winding body. [Figure 7] Figure 7(A) is a perspective view of the wound body, Figure 7(B) shows the internal structure of the secondary battery, and Figure 7(C) shows the external appearance of the secondary battery. [Figure 8] Figures 8(A) and 8(B) show the external appearance of a secondary battery. [Figure 9]Figure 9(A) shows the positive and negative electrodes, Figure 9(B) shows how the electrode tabs are attached, and Figure 9(C) shows how they are enclosed in the outer casing. [Figure 10] Figure 10(A) shows the external appearance of a cylindrical secondary battery, and Figure 10(B) is an exploded perspective view of the cylindrical secondary battery. [Figure 11] Figure 11(A) shows a cross-sectional view of a semi-solid battery, Figure 11(B) shows a cross-sectional view of the positive electrode, and Figure 11(C) shows a cross-sectional view of the electrolyte. [Figure 12] Figures 12(A) to 12(D) are cross-sectional views of the positive electrode. [Figure 13] Figures 13(A) and 13(B) are block diagrams of a vehicle equipped with a battery. [Figure 14] Figure 14(A) is a diagram of an electric vehicle, Figures 14(B) and 14(C) illustrate examples of transport vehicles, and Figure 14(D) illustrates an example of an aircraft. [Figure 15] Figure 15(A) illustrates an example of a portable battery, Figure 15(B) illustrates an example of a stationary battery, and Figure 15(C) illustrates an example of a battery connected to a solar power generation system. [Figure 16] Figures 16(A) and 16(B) illustrate examples of buildings equipped with batteries. [Figure 17] Figure 17 is a graph showing the discharge capacity of the secondary battery in the example. [Modes for carrying out the invention]

[0028] Embodiments of the present invention will be described in detail below with reference to the drawings. However, it will be readily apparent to those skilled in the art that the present invention is not limited to the following description, and its form and details can be modified in various ways. Furthermore, the present invention is not to be interpreted as being limited to the embodiments described below.

[0029] (Embodiment 1) In this embodiment, an example of a storage battery according to one aspect of the present invention will be described using Figures 1(A) to 3(D).

[0030] Figure 1(A) shows an example of a storage battery 100 according to one aspect of the present invention. The storage battery 100 has a lithium-ion secondary battery 101 and a lithium-ion secondary battery 102 adjacent to each other. It is more preferable that the lithium-ion secondary battery 101 and the lithium-ion secondary battery 102 are in contact with each other.

[0031] The lithium-ion secondary battery 101 is a secondary battery that can be charged and discharged even at low temperatures. Low temperatures refer to, for example, 0°C or below, more preferably -20°C or below. In order to enable charging and discharging even at low temperatures, the lithium-ion secondary battery 101 preferably has an ionic liquid as the electrolyte. Alternatively, it is preferable to have a molecular crystalline electrolyte, a semi-solid electrolyte, or a fully solid electrolyte as the electrolyte. Alternatively, it is preferable to have lithium titanate as the negative electrode active material. Not only one of these features, but two or more can be used.

[0032] The lithium-ion secondary battery 102 is a secondary battery that can obtain high charge / discharge characteristics and cycle characteristics in the medium temperature range. The medium temperature range refers to, for example, 0°C to 45°C. In order to obtain high charge / discharge characteristics in the medium temperature range, it is preferable that the lithium-ion secondary battery 102 has an organic solvent as the electrolyte. Furthermore, by using an organic solvent as the electrolyte, it can be manufactured at a lower cost.

[0033] With this configuration, in low-temperature environments, the heat generated during the charging and discharging of the lithium-ion secondary battery 101 can be used as an internal heat source to warm the lithium-ion secondary battery 102. By warming the lithium-ion secondary battery 102 to a medium temperature range, or bringing it close to a medium temperature range, the high charge and discharge characteristics of the lithium-ion secondary battery 102 can be utilized.

[0034] In this specification, when A and B are described as being adjacent, they do not necessarily have to be touching, but they are close enough that heat conduction occurs. For example, if A and B are in the same container, box, or bundle, they can be said to be adjacent.

[0035] Ionic liquids, also known as room-temperature molten salts or low-melting-point molten salts, are salts that exist in a liquid state. Ionic liquids consist of cations and anions, including organic cations and anions. Examples of organic cations used in electrolytes include aliphatic onium cations such as quaternary ammonium cations, tertiary sulfonium cations, and quaternary phosphonium cations, as well as aromatic cations such as imidazolium cations and pyridinium cations. Examples of anions used in electrolytes include monovalent amide anions, monovalent methide anions, fluorosulfonic acid anions, perfluoroalkyl sulfonate anions, tetrafluoroborate anions, perfluoroalkyl borate anions, hexafluorophosphate anions, or perfluoroalkyl phosphate anions. Using one or more of these may improve charge-discharge characteristics at low temperatures. Furthermore, because ionic liquids are flame-retardant and non-volatile, they can prevent the secondary battery from rupturing or catching fire even if the internal temperature rises due to an internal short circuit or overcharging.

[0036] A molecular crystalline electrolyte is a material in which multiple molecules are bonded together by intermolecular interactions, has a crystalline structure, and is lithium ion conductive. Preferably, the molecular crystalline electrolyte is a composite material of a first compound and a second compound. As the first compound, a nitrile solvent can be used; for example, one or more of acetonitrile, succinonitrile, glutaronitrile, and adiponitrile can be used. As the second compound, one or more of lithium bis(fluorosulfonyl)imide (Li(FSO2)2N, abbreviation: LiFSI), lithium bis(trifluoromethanesulfonyl)imide (Li(CF3SO2)2N, abbreviation: LiTFSI), and lithium bis(pentafluoroethanesulfonyl)imide (Li(C2F5SO2)2N, abbreviation: LiBETI) can be used. Since the molecular crystalline electrolyte can also function as a binder, it can contribute to improving electrode density.

[0037] Furthermore, a semi-solid electrolyte refers to a dry (or intrinsic) polymer electrolyte or a polymer gel electrolyte. Here, "semi-solid" does not mean that the solid material makes up 50% of the electrolyte. A semi-solid electrolyte possesses solid properties, such as small volume change, while also exhibiting some liquid-like properties, such as flexibility. As long as these properties are met, it can be a single material or a combination of materials.

[0038] Using a semi-solid electrolyte enhances safety against leakage and other issues. Furthermore, it allows for thinner and lighter secondary batteries.

[0039] As the polymer gel electrolyte, silicone gel, acrylic gel, acrylonitrile gel, polyethylene oxide-based gel, polypropylene oxide-based gel, fluorine-based polymer gel, etc., can be used.

[0040] As the dry polymer electrolyte, for example, polymers having a polyalkylene oxide structure such as polyethylene oxide (PEO), PVDF, polyacrylonitrile, and copolymers containing these can be used. For example, PVDF-HFP, which is a copolymer of PVDF and hexafluoropropylene (HFP), can be used. Further, the polymer formed may have a porous shape.

[0041] In this specification and the like, the all-solid electrolyte refers to a solid having lithium ion conductivity. For example, as the electrolyte of the lithium ion secondary battery 101, a sulfide-based solid electrolyte, an oxide-based solid electrolyte, a halide-based solid electrolyte, etc. can be used.

[0042] The sulfide-based solid electrolytes include thio-LISICON-based (Li 10 GeP2S 12 、Li 3.25 Ge 0.25 P 0.75 S4 etc.), sulfide glasses (70Li2S·30P2S5, 30Li2S·26B2S3·44LiI, 63Li2S·36SiS2·1Li3PO4, 57Li2S·38SiS2·5Li4SiO4, 50Li2S·50GeS2 etc.), sulfide crystallized glasses (Li7P3S 11 、Li 3.25 P 0.95 S4 etc.). Sulfide-based solid electrolytes have advantages such as having materials with high conductivity, being synthesizable at low temperatures, and being relatively soft so that the conductive path is likely to be maintained even after charge and discharge.

[0043] The oxide-based solid electrolytes include materials having a perovskite-type crystal structure (La 2 / 3-x Li 3x TiO3 etc.), materials having a NASICON-type crystal structure (Li 1-X Al X Ti 2-X (PO4)3 etc.), materials having a garnet-type crystal structure (Li7La3Zr2O 12 etc.), materials having a LISICON-type crystal structure (Li 14 ZnGe4O 16etc.), LLZO (Li7La3Zr2O 12 ), oxide glass (Li3PO4-Li4SiO4, 50Li4SiO4·50Li3BO3, etc.), oxide crystallized glass (Li 1.07 Al 0.69 Ti 1.46 (PO4)3, Li 1.5 Al 0.5 Ge 1.5 (PO4)3, etc.) are included. Oxide-based solid electrolytes have the advantage of being stable in the atmosphere.

[0044] Halide-based solid electrolytes include LiAlCl4, Li3InBr6, LiF, LiCl, LiBr, LiI, etc. Also, composite materials in which these halide-based solid electrolytes are filled in the pores of porous aluminum oxide or porous silica can be used as solid electrolytes.

[0045] Also, different solid electrolytes may be mixed and used.

[0046] Among them, Li 1+x Al x Ti 2-x (PO4)3 (0 < x < 1) (hereinafter, LATP) contains aluminum and titanium, elements that the positive electrode active material used in the secondary battery of one aspect of the present invention may have. Therefore, a synergistic effect can be expected for improving the cycle characteristics, which is preferable. Also, an improvement in productivity due to reduction of processes can be expected. In this specification, etc., the NASICON-type crystal structure refers to a compound represented by M2(XO4)3 (M: transition metal, X: S, P, As, Mo, W, etc.), which has a structure in which MO6 octahedra and XO4 tetrahedra share vertices and are three-dimensionally arranged.

[0047] Also, molecular crystal electrolytes, semi-solid electrolytes, and solid electrolytes are also flame-retardant and hardly volatile. Therefore, even if the internal temperature rises due to internal short circuit or overcharging of the secondary battery, rupture and ignition of the secondary battery can be prevented.

[0048] The electrolyte of the lithium-ion secondary battery 102 is preferably an aprotic organic solvent. For example, one of the following can be used as the organic solvent for the electrolyte: ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate, chloroethylene carbonate, vinylene carbonate, γ-butyrolactone, γ-valerolactone, dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), methyl formate, methyl acetate, ethyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, 1,3-dioxane, 1,4-dioxane, dimethoxyethane (DME), dimethyl sulfoxide, diethyl ether, methyl diglyme, acetonitrile, benzonitrile, tetrahydrofuran, sulfolane, sultone, etc., or two or more of these can be used in any combination and ratio.

[0049] Furthermore, examples of electrolytes to be dissolved in the above organic solvent include LiPF6, LiClO4, LiAsF6, LiBF4, LiAlCl4, LiSCN, LiBr, LiI, Li2SO4, and Li2B. 10 Cl 10 Li2B 12 Cl 12 Lithium salts such as LiCF3SO3, LiC4F9SO3, LiC(CF3SO2)3, LiC(C2F5SO2)3, LiN(CF3SO2)2, LiN(C4F9SO2)(CF3SO2), and LiN(C2F5SO2)2 can be used individually or in any combination and ratio of two or more of these salts.

[0050] It is preferable to use a highly purified electrolyte in lithium-ion secondary batteries 101 and 102 that contains little particulate matter and elements other than the constituent elements of the electrolyte (hereinafter also simply referred to as "impurities"). Specifically, it is preferable that the weight ratio of impurities to the electrolyte be 1% or less, preferably 0.1% or less, and more preferably 0.01% or less.

[0051] Furthermore, additives such as vinylene carbonate (VC), propane sultone (PS), tert-butylbenzene (TBB), fluoroethylene carbonate (FEC), lithium bis(oxalate) borate (LiBOB), and dinitrile compounds such as succinonitrile and adiponitrile may be added to the electrolyte. The concentration of the added material should be, for example, 0.1 wt% to 5 wt% relative to the total solvent. VC or LiBOB are particularly preferred because they readily form a good film.

[0052] Figure 1(A) shows an example where the lithium-ion secondary batteries 101 and 102 of the storage battery 100 are both rectangular parallelepipeds, and their largest faces are facing each other. This arrangement can improve the efficiency of heat conduction.

[0053] A rectangular prism is a six-sided shape in which all faces are rectangles. In this specification, these rectangles do not have to be strictly rectangular, nor do they have to be strictly flat. For example, one face may have a positive terminal and / or a negative terminal, or it may have bumps or grooves to increase its strength. Such a shape may also be called a roughly rectangular prism.

[0054] Figure 1(B) shows an example in which both the lithium-ion secondary battery 101 and the lithium-ion secondary battery 102 in the storage battery 100 are cylindrical.

[0055] In this specification, a cylindrical shape refers to a solid whose base and top surfaces are circles. These circles do not have to be perfectly circular or perfectly flat. For example, there may be positive and / or negative terminals, or there may be irregularities to increase strength. Such a shape may also be called a substantially cylindrical shape.

[0056] Figure 1(C) shows an example of a storage battery 100a having a rectangular lithium-ion secondary battery 101 and a lithium-ion secondary battery 102, in addition to a foil-shaped thermal conductive material 110. Figure 1(D) shows an example of a storage battery 100a having a cylindrical lithium-ion secondary battery 101 and a lithium-ion secondary battery 102, in addition to a wire-shaped thermal conductive material 110. Figure 1(E) shows an example of a storage battery 100a having a rectangular lithium-ion secondary battery 101 and a lithium-ion secondary battery 102, in addition to a liquid thermal conductive material 110 and a container 111.

[0057] The storage batteries 100a shown in Figures 1(C) to 1(E) can all improve the efficiency of heat conduction by having a heat conductive material 110 between the lithium-ion secondary battery 101 and the lithium-ion secondary battery 102.

[0058] The thermal conductive material 110 can be any material with a higher thermal conductivity than air. For example, metal foils such as copper foil, metal wires, graphite sheets, silicone oil, antifreeze such as ethylene glycol, etc., can be used. These can also be used in combination. For example, a configuration in which a liquid with high thermal conductivity is circulated inside a metal tube can be used. When the secondary battery and the liquid thermal conductive material 110 are in contact as shown in Figure 1(E), using an insulating thermal conductive material 110 is preferable to improve safety.

[0059] Furthermore, while Figures 1(A) to 1(E) illustrate an example having two types of lithium-ion secondary batteries with different operating temperature ranges, the present invention is not limited to this. It may have three or more types of lithium-ion secondary batteries with different operating temperature ranges.

[0060] Figure 2(A) shows an example of a storage battery 100b having lithium-ion secondary batteries 101a, lithium-ion secondary batteries 101b, and lithium-ion secondary batteries 102. Lithium-ion secondary battery 101a is a secondary battery that operates even in low temperature ranges, for example below 0°C. Lithium-ion secondary battery 101b is a secondary battery that operates even in extremely low temperature ranges, for example below -20°C. Lithium-ion secondary battery 102 is a secondary battery that can obtain high charge and discharge characteristics in the medium temperature range.

[0061] Figure 2(B) shows an example of a storage battery 100c having lithium-ion secondary batteries 101a, 101b, 102a, and 103. Lithium-ion secondary battery 101a is a secondary battery that operates in low temperature ranges, for example below 0°C. Lithium-ion secondary battery 101b is a secondary battery that operates in extremely low temperature ranges, for example below -20°C. Lithium-ion secondary battery 102a is a secondary battery that can obtain high charge / discharge characteristics and cycle characteristics in the medium-low temperature range, for example in the temperature range of 0°C to 25°C. Lithium-ion secondary battery 103 is a secondary battery that can obtain high charge / discharge characteristics and cycle characteristics in the medium-high temperature range, for example in the temperature range of 25°C to 50°C.

[0062] Secondary batteries with different operating temperature ranges can be manufactured, for example, by changing the mixing ratio of ionic liquid and organic solvent in the electrolyte. For example, lithium-ion secondary battery 101b that operates in the cryogenic range uses only ionic liquid as the electrolyte, while lithium-ion secondary battery 101a that operates in the low temperature range can use a mixture of ionic liquid and organic solvent as the electrolyte. Furthermore, for example, lithium-ion secondary battery 103 that operates in the medium-to-high temperature range can use ionic liquid, semi-solid electrolyte, and all-solid electrolyte as the electrolyte and / or electrolyte. Increasing the proportion of conductive material compared to lithium-ion secondary batteries that operate in the lower temperature range suppresses the internal resistance of the lithium-ion secondary battery and allows for better performance in the medium-to-high temperature range. It is also preferable to use conductive materials with good conductivity, such as carbon nanotubes, graphene, and graphene compounds, as the conductive material.

[0063] With this configuration, for example, in extremely low-temperature environments, the heat generated during the charging and discharging of the lithium-ion secondary battery 101b can be used as an internal heat source to warm the other secondary batteries. Furthermore, in environments with moderate or higher temperatures, it can exhibit high charge / discharge characteristics and cycle characteristics. As a result, it is possible to create a storage battery with an even wider operating temperature range.

[0064] Furthermore, it is preferable that the storage battery 100 is arranged such that the lithium-ion secondary battery 102 surrounds or sandwiches the lithium-ion secondary battery 101 which operates in a low-temperature environment. It could also be said that it is preferable to place the lithium-ion secondary battery 101 on the inside.

[0065] Figure 3(A) shows an example of a storage battery 100 having six lithium-ion secondary batteries 102 flanking one lithium-ion secondary battery 101. Figure 3(B) shows an example of a storage battery 100 having three lithium-ion secondary batteries 101 and four lithium-ion secondary batteries 102 alternately. Figure 3(C) shows an example of a storage battery 100 having eight lithium-ion secondary batteries 102 surrounding one lithium-ion secondary battery 101. Figure 3(D) shows an example of a storage battery 100 having fourteen lithium-ion secondary batteries 102 surrounding four lithium-ion secondary batteries 101.

[0066] This configuration allows heat generated from the lithium-ion secondary battery 101 to be efficiently transferred to the lithium-ion secondary battery 102. Furthermore, even with a small number of lithium-ion secondary batteries 101, which tend to be costly, a battery with a wide operating temperature range can be created.

[0067] Similarly, when there are three or more lithium-ion secondary batteries with different operating temperature ranges, it is preferable to place the secondary batteries with lower operating temperature ranges on the inside.

[0068] Furthermore, it is preferable that the storage battery 100 also includes a temperature sensor and a control circuit. The temperature sensor has at least the function of detecting the temperature of the lithium-ion secondary battery 102. It is preferable that the control circuit has the function of causing the lithium-ion secondary battery 101 to self-heat and heat the lithium-ion secondary battery 102 until it reaches the operating temperature range when the lithium-ion secondary battery 102 is at a temperature lower than the operating temperature range.

[0069] For example, in the case of a storage battery 100 having a lithium-ion secondary battery 101 with an operating temperature range of -20°C to 0°C, a lithium-ion secondary battery 102 with an operating temperature range of 0°C to 45°C, a temperature sensor, and a control circuit, it is preferable that the control circuit has a function to self-heat the lithium-ion secondary battery 101 and heat it up to the range of 0°C to 45°C when the temperature sensor detects that the temperature of the lithium-ion secondary battery 102 has fallen below 0°C, thereby bringing the lithium-ion secondary battery 102 within the range of 0°C to 45°C.

[0070] Furthermore, when the lithium-ion secondary battery 102 is within its operating temperature range, the lithium-ion secondary battery 101 may or may not be driven, i.e., it may be charged and discharged. For example, the control circuit may have a function to drive the lithium-ion secondary battery 101 when the temperature is below 25°C and not drive the lithium-ion secondary battery 101 when the temperature is 25°C or higher.

[0071] The method for causing the lithium-ion secondary battery 101 to generate its own heat is not particularly limited. Self-heating of the lithium-ion secondary battery 101 can occur even during normal charging and discharging.

[0072] Furthermore, the battery 100 may consist of multiple lithium-ion secondary batteries 101 and an inverter. With this configuration, the discharge current of one lithium-ion secondary battery 101 can be converted into an alternating current by the inverter, and this alternating current can be used to repeatedly charge and discharge another lithium-ion secondary battery 101. This operation also generates self-heating of the lithium-ion secondary battery 101.

[0073] For example, in the case of a storage battery 100 having two or more lithium-ion secondary batteries 101 with an operating temperature range of -20°C or more and 0°C or less, lithium-ion secondary batteries 102 with an operating temperature range of 0°C or more and 45°C, a temperature sensor, a control circuit, and an inverter, it is preferable that the control circuit has a function in which, when the temperature sensor detects that the temperature of one lithium-ion secondary battery 102 is below 0°C, it converts the discharge current of one lithium-ion secondary battery 101 into an alternating current using the inverter, and heats up the other lithium-ion secondary battery 101 by repeatedly charging and discharging it using the alternating current, thereby causing it to self-heat and bring the lithium-ion secondary battery 102 within the range of 0°C or more and 45°C or less.

[0074] Furthermore, it is more preferable that the control circuit not only controls the temperature but also has the function of detecting at least one of overcharging, over-discharging, or overcurrent to protect the lithium-ion secondary battery 101 and lithium-ion secondary battery 102.

[0075] Alternatively, the storage battery 100 may not discharge to the outside if the lithium-ion secondary battery 102 is below its operating temperature range, and may only begin discharging to the outside after the lithium-ion secondary battery 102 has been heated by the lithium-ion secondary battery 101 and is within its operating temperature range. In this case, the lithium-ion secondary battery 101 can be said to function as a residual heat source.

[0076] In the description of the temperature sensor and control circuit, a storage battery having two types of lithium-ion secondary batteries was used as an example, but the present invention is not limited to this. In the case of a storage battery having three or more types of lithium-ion secondary batteries, a temperature sensor, and a control circuit, the functions of the temperature sensor and control circuit can also be set in reference to the above description.

[0077] This embodiment can be used in combination with other embodiments.

[0078] (Embodiment 2) In this embodiment, a more specific example of a storage battery according to one aspect of the present invention will be described using Figures 4(A) to 5(B).

[0079] Figure 4(A) shows an example of a storage battery according to one embodiment of the present invention. The storage battery 220 includes a plurality of secondary batteries 200, a case 222 in which the plurality of secondary batteries 200 are housed, and a control circuit 221. The combination of the plurality of secondary batteries 200 can be considered in reference to the previous embodiment.

[0080] Figure 4(B) is a perspective view of a storage battery according to one embodiment of the present invention, and Figure 4(C) is a top view of a storage battery according to one embodiment of the present invention. The storage battery 230 has a plurality of secondary batteries 600 and a heat conductive material 231. For simplicity, Figure 4(B) shows only a selection of secondary batteries 600. Some of the secondary batteries 600 are electrically connected by conductors 232. The heat conductive material 231 shown in Figure 4(C) has a configuration in which a liquid with high thermal conductivity is circulated inside a metal tube. By providing the heat conductive material 231 so as to run between the secondary batteries 600 in this way, the efficiency of heat conduction can be increased. The combination of the plurality of secondary batteries 600 can be considered in the previous embodiment.

[0081] Figure 5(A) is a diagram illustrating the configuration of a storage battery according to one embodiment of the present invention, and Figure 5(B) is a perspective view of a storage battery according to one embodiment of the present invention. The storage battery 240 includes a plurality of secondary batteries 241, conductive materials 242a and 242b electrically connected to the plurality of secondary batteries 241, and retaining materials 243a, 243b and 243c for housing these. Preferably, a part of the retaining material is provided with positive and negative terminals electrically connected to the conductive materials 242a and 242b. The combination of the plurality of secondary batteries 241 can be considered in reference to the previous embodiment.

[0082] The strength of the storage battery 240 can be increased by arranging multiple elongated secondary batteries, such as secondary battery 241, in a single array.

[0083] This embodiment can be used in combination with other embodiments.

[0084] (Embodiment 3) In this embodiment, examples of secondary batteries and their materials that can be used in a storage battery according to one aspect of the present invention will be described using Figures 6(A) to 10(B).

[0085] First, an example of the structure of a roughly rectangular secondary battery will be explained using Figures 6(A) to 7(C). The secondary battery 913 shown in Figure 6(A) has a wound body 950 with terminals 951 and 952 inside a housing 930. Terminal 952 is in contact with the housing 930, while terminal 951 is not in contact with the housing 930 due to the use of insulating material or the like. In Figure 6(A), the housing 930 is shown separated for convenience, but in reality, the wound body 950 is covered by the housing 930, and terminals 951 and 952 extend outside the housing 930. The housing 930 can be made of a metal material (e.g., aluminum) or a resin material.

[0086] Furthermore, as shown in Figure 6(B), the housing 930 shown in Figure 6(A) may be formed from multiple materials. For example, in the secondary battery 913 shown in Figure 6(B), housing 930a and housing 930b are bonded together, and the winding body 950 is provided in the area surrounded by housing 930a and housing 930b.

[0087] For the housing 930a, an insulating material such as organic resin can be used. In particular, by using a material such as organic resin on the surface where the antenna is formed, shielding of the electric field by the secondary battery 913 can be suppressed. If the shielding of the electric field by housing 930a is small, the antenna may be placed inside housing 930a. For housing 930b, for example, a metal material can be used.

[0088] Furthermore, the structure of the wound body 950 is shown in Figure 6(C). The wound body 950 has a negative electrode 931, a positive electrode 932, and a separator 933. The wound body 950 is a wound body in which the negative electrode 931 and the positive electrode 932 are stacked on top of each other with the separator 933 in between, and the stacked sheets are wound up. Note that multiple stacks of the negative electrode 931, positive electrode 932, and separator 933 may be stacked.

[0089] Alternatively, the secondary battery 913 may have a wound body 950a as shown in Figure 7. The wound body 950a shown in Figure 7(A) has a negative electrode 931, a positive electrode 932, and a separator 933. The negative electrode 931 has a negative electrode active material layer 931a. The positive electrode 932 has a positive electrode active material layer 932a.

[0090] The separator 933 has a wider width than the negative electrode active material layer 931a and the positive electrode active material layer 932a, and is wound so as to overlap with the negative electrode active material layer 931a and the positive electrode active material layer 932a. Furthermore, it is preferable from a safety standpoint that the negative electrode active material layer 931a is wider than the positive electrode active material layer 932a. A wound body 950a of this shape is also preferable due to its good safety and productivity.

[0091] As shown in Figure 7(B), the negative electrode 931 is electrically connected to terminal 951. Terminal 951 is electrically connected to terminal 911a. The positive electrode 932 is electrically connected to terminal 952. Terminal 952 is electrically connected to terminal 911b. As shown in Figure 7(B), two winding bodies 950a are housed in a single housing 930.

[0092] As shown in Figure 7(C), the coiled body 950a and the like are covered by the housing 930, forming a secondary battery 913. It is preferable to provide a safety valve, an overcurrent protection element, etc., in the housing 930. The safety valve is a valve that opens the inside of the housing 930 at a predetermined internal pressure in order to prevent the battery from rupturing.

[0093] As shown in Figure 7(B), the secondary battery 913 may have multiple windings 950a. By using multiple windings 950a, a secondary battery 913 with a larger charge / discharge capacity can be made. Other elements of the secondary battery 913 shown in Figures 7(A) and (B) can be considered in reference to the description of the secondary battery 913 shown in Figures 6(A) to (C).

[0094] Next, an example of a laminate-type secondary battery is shown in Figures 8(A) and 8(B), which show an example of its external appearance. The secondary battery 500 shown in Figures 8(A) and 8(B) has a positive electrode 503, a negative electrode 506, a separator 507, an outer casing 509, a positive electrode lead electrode 510, and a negative electrode lead electrode 511.

[0095] Figure 9(A) shows the external views of the positive electrode 503 and the negative electrode 506. The positive electrode 503 has a positive electrode current collector 501, and the positive electrode active material layer 502 is formed on the surface of the positive electrode current collector 501. The positive electrode 503 also has a region where the positive electrode current collector 501 is partially exposed (hereinafter referred to as the tab region). The negative electrode 506 has a negative electrode current collector 504, and the negative electrode active material layer 505 is formed on the surface of the negative electrode current collector 504. The negative electrode 506 also has a region where the negative electrode current collector 504 is partially exposed, i.e., the tab region. The area and shape of the tab regions of the positive and negative electrodes are not limited to the example shown in Figure 9(A).

[0096] Here, an example of a method for manufacturing a laminate-type secondary battery, whose external view is shown in Figure 8(A), will be explained using Figures 9(B) and 9(C).

[0097] First, the negative electrode 506, separator 507, and positive electrode 503 are stacked. Figure 9(B) shows the stacked negative electrode 506, separator 507, and positive electrode 503. Here, an example using 5 sets of negative electrodes and 4 sets of positive electrodes is shown. This can also be called a laminate consisting of negative electrodes, separators, and positive electrodes. Next, the tab regions of the positive electrode 503 are joined together, and the positive electrode lead electrode 510 is joined to the tab region of the outermost positive electrode. For joining, ultrasonic welding, for example, can be used. Similarly, the tab regions of the negative electrode 506 are joined together, and the negative electrode lead electrode 511 is joined to the tab region of the outermost negative electrode.

[0098] Next, the negative electrode 506, separator 507, and positive electrode 503 are placed on the outer casing 509.

[0099] Next, an example of a cylindrical secondary battery will be described with reference to Figure 10. As shown in Figure 10(A), the cylindrical secondary battery 600 has a positive electrode cap (battery cover) 601 on the top surface and a battery casing (outer casing) 602 on the sides and bottom. These positive electrode cap and battery casing (outer casing) 602 are insulated by a gasket (insulating packing) 610.

[0100] Figure 10(B) is a schematic diagram showing a cross-section of a cylindrical secondary battery. Inside the hollow cylindrical battery casing 602, a battery element is provided, in which a strip-shaped positive electrode 604 and a negative electrode 606 are wound with a separator 605 in between. Although not shown, the battery element is wound around a center pin. The battery casing 602 is closed at one end and open at the other. The battery casing 602 can be made of a metal such as nickel, aluminum, or titanium, which is corrosion-resistant to solvents, or an alloy of these metals or an alloy of these metals with other metals (for example, stainless steel). Furthermore, it is preferable to coat it with nickel or aluminum to prevent corrosion by solvents. Inside the battery casing 602, the battery element, in which the positive electrode, negative electrode, and separator are wound, is sandwiched between a pair of opposing insulating plates 608 and 609. In addition, a non-aqueous electrolyte (not shown) is injected into the inside of the battery casing 602 in which the battery element is provided. The non-aqueous electrolyte can be the same as that used in the secondary battery of the previous embodiment.

[0101] Since the positive and negative electrodes used in cylindrical storage batteries are wound, it is preferable to form active material on both sides of the current collector. A positive electrode terminal (positive electrode current collector lead) 603 is connected to the positive electrode 604, and a negative electrode terminal (negative electrode current collector lead) 607 is connected to the negative electrode 606. Both the positive electrode terminal 603 and the negative electrode terminal 607 can be made of metal materials such as aluminum. The positive electrode terminal 603 is resistance-welded to the safety valve mechanism 613, and the negative electrode terminal 607 is resistance-welded to the bottom of the battery can 602. The safety valve mechanism 613 is electrically connected to the positive electrode cap 601 via a PTC element (Positive Temperature Coefficient) 611. The safety valve mechanism 613 disconnects the electrical connection between the positive electrode cap 601 and the positive electrode 604 when the rise in the internal pressure of the battery exceeds a predetermined threshold. Furthermore, the PTC element 611 is a thermal resistance element whose resistance increases when the temperature rises, and it prevents abnormal heat generation by limiting the current amount through the increase in resistance. Barium titanate (BaTiO3) based semiconductor ceramics can be used for the PTC element.

[0102] [Negative electrode] The negative electrode comprises a negative electrode active material layer and a negative electrode current collector. The negative electrode active material layer may also contain a conductive material and a binder.

[0103] <Negative electrode active material> For example, alloy-based materials and / or carbon-based materials can be used as the negative electrode active material.

[0104] As the negative electrode active material, elements capable of undergoing charge-discharge reactions through alloying and dealloying reactions with lithium can be used. For example, materials containing at least one of silicon, tin, gallium, aluminum, germanium, lead, antimony, bismuth, silver, zinc, cadmium, indium, etc., can be used. Such elements have a larger capacity than carbon, and silicon in particular has a high theoretical capacity of 4200 mAh / g. For this reason, it is preferable to use silicon as the negative electrode active material. Compounds containing these elements may also be used. Examples include SiO, Mg2Si, Mg2Ge, SnO, SnO2, Mg2Sn, SnS2, V2Sn3, FeSn2, CoSn2, Ni3Sn2, Cu6Sn5, Ag3Sn, Ag3Sb, Ni2MnSb, CeSb3, LaSn3, La3Co2Sn7, CoSb3, InSb, SbSn, etc. In this context, elements capable of undergoing charge-discharge reactions through alloying and de-alloying reactions with lithium, and compounds containing such elements, are sometimes referred to as alloying materials.

[0105] In this specification, SiO refers to silicon monoxide, for example. Alternatively, SiO refers to SiO x It can also be expressed as follows. Here, x is preferably 1 or a value in its immediate vicinity. For example, x is preferably between 0.2 and 1.5, and preferably between 0.3 and 1.2.

[0106] Suitable carbon-based materials include graphite, easily graphitizable carbon (soft carbon), difficult-to-graphitize carbon (hard carbon), carbon nanotubes, graphene, and carbon black.

[0107] Examples of graphite include artificial graphite and natural graphite. Examples of artificial graphite include mesocarbon microbeads (MCMB), coke-based artificial graphite, and pitch-based artificial graphite. Here, spheroidal graphite having a spherical shape can be used as artificial graphite. For example, MCMB may have a spherical shape and is therefore preferable. Furthermore, it is relatively easy to reduce the surface area of ​​MCMB, which may also be preferable. Examples of natural graphite include flake graphite and spheroidized natural graphite.

[0108] When lithium ions are inserted into graphite (during the formation of lithium-graphite intercalation compounds), graphite exhibits a potential as low as that of lithium metal (0.05V to 0.3V vs. Li / Li). + This allows lithium-ion secondary batteries to exhibit a high operating voltage. Furthermore, graphite is preferred because it has advantages such as a relatively high capacity per unit volume, relatively small volume expansion, low cost, and higher safety compared to lithium metal.

[0109] Furthermore, titanium dioxide (TiO2) and lithium titanium oxide (Li4Ti5O2) are used as negative electrode active materials. 12 ), lithium-graphite intercalation compound (Li x Oxides such as C6, niobium pentoxide (Nb2O5), tungsten oxide (WO2), and molybdenum oxide (MoO2) can be used.

[0110] Furthermore, as the negative electrode active material, a Li3N type structure is used, which is a lithium and transition metal binitride. 3-x M x N (M = Co, Ni, Cu) can be used. For example, Li 2.6 Co 0.4 The N3 has a large charge / discharge capacity (900mAh / g, 1890mAh / cm²). 3 ) indicates a preference.

[0111] Using a lithium-transition metal complex nitride is preferable because it contains lithium ions in the negative electrode active material, allowing it to be combined with lithium-ion-free materials such as V2O5 and Cr3O8 as the positive electrode active material. Even when using a lithium-ion-containing material as the positive electrode active material, the lithium-transition metal complex nitride can be used as the negative electrode active material by pre-desorbing the lithium ions contained in the positive electrode active material.

[0112] Furthermore, materials that undergo a conversion reaction can also be used as the negative electrode active material. For example, transition metal oxides that do not form alloys with lithium, such as cobalt oxide (CoO), nickel oxide (NiO), and iron oxide (FeO), may be used as the negative electrode active material. Other materials that undergo a conversion reaction include oxides such as Fe2O3, CuO, Cu2O, RuO2, Cr2O3, and CoS 0.89 This can also occur with sulfides such as NiS and CuS, nitrides such as Zn3N2, Cu3N, and Ge3N4, phosphides such as NiP2, FeP2, and CoP3, and fluorides such as FeF3 and BiF3.

[0113] Typical conductive materials that can be present in the negative electrode active material layer include carbon black (furnace black, acetylene black, graphite, etc.). Graphene and graphene compounds may also be used as conductive materials.

[0114] Graphene is a carbon material that possesses remarkable electrical, mechanical, and chemical properties, making it promising for applications in various fields, including field-effect transistors and solar cells.

[0115] In this specification, the term "graphene compound" includes multilayer graphene, multigraphene, graphene oxide, multilayer graphene oxide, multigraphene oxide, reduced graphene oxide, reduced multilayer graphene oxide, reduced multigraphene oxide, etc. A graphene compound is defined as a material having carbon atoms, having a plate-like or sheet-like shape, and possessing a two-dimensional structure formed by six-membered carbon rings. It is also preferable that it has a bent shape. It may also be called a carbon sheet. It is also preferable that it has functional groups. Furthermore, the graphene compound may be rolled up to resemble carbon nanofibers.

[0116] Graphene and graphene compounds may possess excellent electrical properties, such as high conductivity, and excellent physical properties, such as high flexibility and high mechanical strength. Furthermore, graphene and graphene compounds may have a sheet-like shape. Graphene and graphene compounds may have curved surfaces, enabling surface contact with low contact resistance. They may also exhibit very high conductivity even when thin, allowing for efficient formation of conductive paths within the active material layer with a small amount. Therefore, using graphene and graphene compounds as conductive materials can increase the contact area between the active material and the conductive material. It is preferable that the graphene or graphene compound adheres to at least a portion of the active material. It is also preferable that the graphene or graphene compound overlaps at least a portion of the active material. Furthermore, it is preferable that the shape of the graphene or graphene compound matches at least a portion of the shape of the active material. The shape of the active material refers, for example, to the irregularities of a single active material particle, or the irregularities formed by multiple active material particles. It is also preferable that the graphene or graphene compound surrounds at least a portion of the active material. Furthermore, graphene or graphene compounds may have holes.

[0117] As binders that the negative electrode active material layer may contain, it is preferable to use rubber materials such as styrene-butadiene rubber (SBR), styrene-isoprene-styrene rubber, acrylonitrile-butadiene rubber, butadiene rubber, and ethylene-propylene-diene copolymer. Fluororubber is also an example of a binder. In this specification, a binder refers to a polymer compound mixed solely for the purpose of binding the active material, conductive material, etc., onto the current collector.

[0118] <Negative electrode current collector> The negative electrode current collector can be made from the same material as the positive electrode current collector. However, it is preferable to use a material for the negative electrode current collector that does not alloy with carrier ions such as lithium.

[0119] [Separator] A separator is placed between the positive and negative electrodes. The separator can be made from materials such as cellulose fibers including paper, nonwoven fabrics, glass fibers, ceramics, or synthetic fibers using nylon (polyamide), vinylon (polyvinyl alcohol-based fiber), polyester, acrylic, polyolefin, or polyurethane. It is preferable that the separator be processed into a bag shape and positioned to enclose either the positive or negative electrode.

[0120] The separator may have a multilayer structure. For example, an organic material film such as polypropylene or polyethylene can be coated with a ceramic material, a fluorine material, a polyamide material, or a mixture thereof. Examples of ceramic materials include aluminum oxide particles and silicon oxide particles. Examples of fluorine materials include PVDF and polytetrafluoroethylene. Examples of polyamide materials include nylon and aramid (meta-aramid, para-aramid).

[0121] Coating with ceramic materials improves oxidation resistance, suppressing separator degradation during high-voltage charging and discharging, and thus improving the reliability of secondary batteries. Coating with fluorine-based materials improves adhesion between the separator and electrodes, thereby improving output characteristics. Coating with polyamide materials, particularly aramid, improves heat resistance, thus enhancing the safety of secondary batteries.

[0122] For example, a polypropylene film may be coated on both sides with a mixture of aluminum oxide and aramid. Alternatively, the side of the polypropylene film in contact with the positive electrode may be coated with a mixture of aluminum oxide and aramid, and the side in contact with the negative electrode may be coated with a fluorine-based material.

[0123] By using a multi-layered separator, the safety of the secondary battery can be maintained even if the overall thickness of the separator is thin, thus increasing the capacity per unit volume of the secondary battery.

[0124] [Positive electrode] The positive electrode comprises a positive electrode active material layer and a positive electrode current collector. The positive electrode active material layer may also contain a conductive material and a binder.

[0125] <Cathode active material> The positive electrode active material preferably contains a metal (hereinafter referred to as element A) that acts as a carrier ion. For example, alkali metals such as lithium, sodium, and potassium, and group 2 elements such as calcium, beryllium, and magnesium can be used as element A.

[0126] In a positive electrode active material, carrier ions are released from the positive electrode active material during charging. If a large amount of element A is released, more ions contribute to the capacity of the secondary battery, increasing the capacity. On the other hand, if a large amount of element A is released, the crystal structure of the compound contained in the positive electrode active material is more likely to collapse. Collapse of the crystal structure of the positive electrode active material may lead to a decrease in discharge capacity with charge-discharge cycles. If the positive electrode active material contains element X, the collapse of the crystal structure when carrier ions are released during charging of the secondary battery may be suppressed. Element X is, for example, partially substituted for element A. Element X can be magnesium, calcium, zirconium, lanthanum, barium, etc. Alternatively, element X can be copper, potassium, sodium, zinc, etc. Two or more of the above elements may be used in combination as element X.

[0127] Furthermore, the positive electrode active material preferably contains a halogen in addition to element X. It is preferable that it contains halogens such as fluorine and chlorine. The presence of such halogens in the positive electrode active material may promote the substitution of element X to the position of element A.

[0128] If the positive electrode active material contains element X, or if it contains a halogen in addition to element X, the electrical conductivity on the surface of the positive electrode active material may be suppressed.

[0129] Furthermore, the positive electrode active material contains a metal (hereinafter referred to as element M) whose valency changes during charging and discharging of the secondary battery. Element M is, for example, a transition metal. The positive electrode active material contains, for example, one or more of cobalt, nickel, and manganese as element M, and particularly cobalt. In addition, the position of element M may contain an element that does not change in valency and can take the same valency as element M, such as aluminum, more specifically, a trivalent typical element. The aforementioned element X may be substituted, for example, at the position of element M. Also, if the positive electrode active material is an oxide, element X may be substituted at the position of oxygen.

[0130] For example, it is preferable to use a lithium composite oxide having a layered rock salt crystal structure as the positive electrode active material. More specifically, examples of lithium composite oxides having a layered rock salt crystal structure include lithium cobaltate, lithium nickelate, lithium composite oxides containing nickel, manganese, and cobalt, lithium composite oxides containing nickel, cobalt, and aluminum, etc. Furthermore, it is preferable that these positive electrode active materials are represented by the space group R-3m.

[0131] In positive electrode active materials having a layered rock salt crystal structure, increasing the charging depth may cause a breakdown of the crystal structure. Here, a breakdown of the crystal structure refers to, for example, a shift in the layers. If the breakdown of the crystal structure is irreversible, the capacity of the secondary battery may decrease with repeated charging and discharging.

[0132] The presence of element X in the positive electrode active material suppresses the shifting of the layers, even when the charging depth increases. By suppressing this shifting, the volume change during charging and discharging can be reduced. Therefore, the positive electrode active material can achieve excellent cycle characteristics. Furthermore, the positive electrode active material can adopt a stable crystal structure in a high-voltage charging state. Therefore, when the positive electrode active material maintains a high-voltage charging state, short circuits are less likely to occur. In such cases, safety is further improved, which is preferable.

[0133] In positive electrode active materials, the difference in crystal structure and volume per unit number of transition metal atoms between a fully discharged state and a high-voltage charged state is small.

[0134] The positive electrode active material has the chemical formula AM y O Z It can sometimes be represented as (y>0, z>0). For example, lithium cobalt oxide can be represented as LiCoO2. Also, lithium nickelate can be represented as LiNiO2.

[0135] The number of atoms of element X is preferably 0.001 times or more and 0.1 times or less than the number of atoms of element M, more preferably greater than 0.01 times and less than 0.04 times, and even more preferably about 0.02 times. The concentration of element X shown here may be, for example, a value obtained by elemental analysis of the entire particle of the positive electrode active material using ICP-MS, or it may be based on the value of the raw material composition during the manufacturing process of the positive electrode active material.

[0136] When element M contains cobalt and nickel, the ratio of the number of nickel atoms (Ni) to the sum of the number of cobalt and nickel atoms (Co+Ni), Ni / (Co+Ni), is preferably less than 0.1, and more preferably 0.075 or less.

[0137] The positive electrode active material is not limited to the materials listed above.

[0138] For example, a composite oxide having a spinel-type crystal structure can be used as the positive electrode active material. Alternatively, for example, a polyanionic material can be used as the positive electrode active material. Examples of polyanionic materials include materials having an olivine-type crystal structure, nasicone-type materials, and so on. Furthermore, for example, a material containing sulfur can be used as the positive electrode active material.

[0139] As a material having a spinel-type crystal structure, for example, a composite oxide represented by LiM2O4 can be used. It is preferable that the element M is Mn. For example, LiMn2O4 can be used. Furthermore, by having Ni in addition to Mn as element M, the discharge voltage of the secondary battery may be improved and the energy density may be improved, which is preferable. In addition, a small amount of lithium nickelate (LiNiO2 or LiNi) can be added to a lithium-containing material having a spinel-type crystal structure containing manganese, such as LiMn2O4. 1-x M x Mixing O2 (M=Co, Al, etc.) can improve the characteristics of the secondary battery, which is preferable.

[0140] As a polyanionic material, for example, a composite oxide having oxygen, metal A, metal M, and element Z can be used. Metal A is one or more of Li, Na, Mg, metal M is one or more of Fe, Mn, Co, Ni, Ti, V, Nb, and element Z is one or more of S, P, Mo, W, As, Si.

[0141] As a material having an olivine-type crystal structure, for example, composite materials (general formula LiMPO4 (where M is one or more of Fe(II), Mn(II), Co(II), Ni(II))) can be used. Representative examples of general formula LiMPO4 include LiFePO4, LiNiPO4, LiCoPO4, LiMnPO4, and LiFe a Ni b PO4, LiFe a Co b PO4, LiFe a Mn b PO4, LiNi a Co b PO4, LiNi a Mn b PO4(a+b is less than or equal to 1, 0 <a<1、0<b<1)、LiFe c Ni d Co e PO4, LiFe c Ni d Mn e PO4, LiNi c Co d Mn ePO4 (where c + d + e ≤ 1, 0 < c < 1, 0 < d < 1, 0 < e < 1), LiFe f Ni g Co h Mn i PO4 (where f + g + h + i ≤ 1, 0 < f < 1, 0 < g < 1, 0 < h < 1, 0 < i < 1), etc. can be used as lithium compounds.

[0142] Also, composite materials such as general formula Li (2-j) MSiO4 (M is one or more of Fe(II), Mn(II), Co(II), Ni(II), 0 ≤ j ≤ 2), etc. can be used. For the general formula Li (2-j) Representative examples of MSiO4 include Li (2-j) FeSiO4, Li (2-j) NiSiO4, Li (2-j) CoSiO4, Li (2-j) MnSiO4, Li (2-j) Fe k Ni l SiO4, Li (2-j) Fe k Co l SiO4, Li (2-j) Fe k Mn l SiO4, Li (2-j) Ni k Co l SiO4, Li (2-j) Ni k Mn l SiO4 (where k + l ≤ 1, 0 < k < 1, 0 < l < 1), Li (2-j) Fe m Ni n Co q SiO4, Li (2-j) Fe m Ni n Mn q SiO4, Li (2-j) Ni m Co n Mn q SiO4 (where m + n + q ≤ 1, 0 < m < 1, 0 < n < 1, 0 < q < 1), Li (2-j) Fe r Ni s Co t Mn uLithium compounds such as SiO4 (where r + s + t + u ≤ 1, 0 < r < 1, 0 < s < 1, 0 < t < 1, 0 < u < 1) can be used.

[0143] Also, A x Nasicon-type compounds represented by the general formula M2(XO4)3 (A = Li, Na, Mg, M = Fe, Mn, Ti, V, Nb, X = S, P, Mo, W, As, Si) can be used. Examples of nasicon-type compounds include Fe2(MnO4)3, Fe2(SO4)3, Li3Fe2(PO4)3, etc. Also, as the positive electrode active material, compounds represented by the general formula Li2MPO4F, Li2MP2O7, Li5MO4 (M = Fe, Mn) can be used.

[0144] Also, as the positive electrode active material, perovskite-type fluorides such as NaFeF3, FeF3, metal chalcogenides (sulfides, selenides, tellurides) such as TiS2, MoS2, oxides having an inverse spinel-type crystal structure such as LiMVO4, vanadium oxide-based (V2O5, V6O 13 , LiV3O8, etc.), manganese oxides, organic sulfur compounds and other materials may be used.

[0145] Also, as the positive electrode active material, borate-based materials represented by the general formula LiMBO3 (M is Fe(II), Mn(II), Co(II)) may be used.

[0146] Examples of materials containing sodium include sodium-containing oxides such as NaFeO2, Na 2 / 3 [Fe 1 / 2 Mn 1 / 2 O2, Na 2 / 3 [Ni 1 / 3 Mn 2 / 3 O2, Na2Fe2(SO4)3, Na3V2(PO4)3, Na2FePO4F, NaVPO4F, NaMPO4 (M is Fe(II), Mn(II), Co(II), Ni(II)), Na2FePO4F, Na4Co3(PO4)2P2O7, etc., may be used as the positive electrode active material.

[0147] Furthermore, lithium-containing metal sulfides may be used as the positive electrode active material. Examples include Li2TiS3 and Li3NbS4.

[0148] In this embodiment, two or more of the materials listed above may be used as the positive electrode active material by mixing them.

[0149] This embodiment can be freely combined with other embodiments.

[0150] (Embodiment 4) This embodiment shows an example of fabricating a semi-solid battery as a secondary battery that operates at low temperatures, as shown in Embodiment 1.

[0151] Figure 11(A) is a schematic cross-sectional view of a secondary battery 1000 according to one embodiment of the present invention. The secondary battery 1000 has a positive electrode 1006, an electrolyte layer 1003, and a negative electrode 1007. The positive electrode 1006 has a positive electrode current collector 1001 and a positive electrode active material layer 1002. The negative electrode 1007 has a negative electrode current collector 1005 and a negative electrode active material layer 1004.

[0152] Figure 11(B) is a schematic cross-sectional view of the positive electrode 1006. The positive electrode active material layer 1002 of the positive electrode 1006 comprises a positive electrode active material 1011, an electrolyte 1010, and a conductive material (also called a conductive additive). The electrolyte 1010 comprises a lithium-ion conductive polymer and a lithium salt. It is preferable that the positive electrode active material layer 1002 does not contain a binder.

[0153] Figure 11(C) is a schematic cross-sectional view of the electrolyte layer 1003. The electrolyte layer 1003 has an electrolyte 1010 which contains a lithium-ion conductive polymer and a lithium salt.

[0154] In this specification, a lithium-ion conductive polymer is a polymer that has the conductivity of a cation such as lithium. More specifically, it is a polymer compound having a polar group to which a cation can coordinate. Preferably, the polar group is an ether group, ester group, nitrile group, carbonyl group, siloxane, etc.

[0155] Examples of lithium-ion conductive polymers that can be used include polyethylene oxide (PEO), derivatives having polyethylene oxide as the main chain, polypropylene oxide, polyacrylic acid esters, polymethacrylate esters, polysiloxanes, and polyphosphazenes.

[0156] The lithium-ion conductive polymer may be branched, crosslinked, or copolymerized. Its molecular weight is preferably, for example, 10,000 or more, and more preferably 100,000 or more.

[0157] In lithium-ion conductive polymers, lithium ions move while changing the polar groups they interact with through partial motion (also called segmental motion) of the polymer chains. For example, in PEO, lithium ions move while changing the oxygen groups they interact with through segmental motion of the ether chains. When the temperature is close to or higher than the melting or softening point of the lithium-ion conductive polymer, the crystalline region dissolves and the amorphous region increases, and the motion of the ether chains becomes more active, resulting in higher ionic conductivity. Therefore, when using PEO as a lithium-ion conductive polymer, it is preferable to perform charging and discharging at 60°C or higher.

[0158] According to Shannon et al., Acta A 32 (1976) 751, the radius of a monovalent lithium ion is 0.0590 nm for 4-coordinate, 0.076 nm for 6-coordinate, and 0.092 nm for 8-coordinate. The radius of a divalent oxygen ion is 0.135 nm for 2-coordinate, 0.136 nm for 3-coordinate, 0.138 nm for 4-coordinate, 0.140 nm for 6-coordinate, and 0.142 nm for 8-coordinate. The distance between polar groups in adjacent lithium-ion conductive polymer chains is preferably greater than the distance at which lithium ions and the anions of the polar groups can stably exist while maintaining the above-mentioned ionic radii. Furthermore, it is preferable that the distance is such that sufficient interaction occurs between lithium ions and polar groups. However, as mentioned above, segmental motion occurs, so it is not necessary to always maintain a constant distance. It is sufficient if the distance is appropriate when lithium ions pass through.

[0159] Furthermore, as lithium salts, compounds containing lithium along with at least one of the following can be used: phosphorus, fluorine, nitrogen, sulfur, oxygen, chlorine, arsenic, boron, aluminum, bromine, and iodine. For example, LiPF6, lithium bis(fluorosulfonyl)imide (Li(FSO2)2N, abbreviated as LiFSI), LiClO4, LiAsF6, LiBF4, LiAlCl4, LiSCN, LiBr, LiI, Li2SO4, Li2B 10 Cl 10 Li2B 12 Cl 12 Lithium salts such as LiCF3SO3, LiC4F9SO3, LiC(CF3SO2)3, LiC(C2F5SO2)3, LiN(CF3SO2)2, LiN(C4F9SO2)(CF3SO2), LiN(C2F5SO2)2, lithium bis(oxalate) borate (LiBOB), etc., can be used individually or in any combination and ratio of two or more of these.

[0160] In particular, using LiFSI is preferable because it exhibits good low-temperature characteristics. Furthermore, LiFSI and LiTFSI are less reactive with water compared to LiPF6 and the like. Therefore, it is easier to control the dew point when fabricating electrodes and electrolyte layers using LiFSI. For example, they can be handled not only in an inert atmosphere such as argon with moisture removed as much as possible, and in a dry room with controlled dew point, but also in a normal atmospheric atmosphere. This improves productivity, which is preferable. Moreover, using Li salts with high dissociability and plasticizing effects, such as LiFSI and LiTFSI, is particularly preferable when using lithium conduction utilizing the segmental motion of the ether chain, because it can be used over a wide temperature range.

[0161] Since lithium-ion conductive polymers are polymer compounds, thoroughly mixing them and using them in the positive electrode active material layer 1002 makes it possible to bond the positive electrode active material 1011 and conductive material onto the positive electrode current collector 1001. Therefore, the positive electrode 1006 can be manufactured without using a binder. A binder is a material that does not contribute to the charge-discharge reaction. Therefore, the less binder there is, the more materials that contribute to charge-discharge, such as the active material and electrolyte, can be increased. As a result, a secondary battery 1000 with improved discharge capacity, rate characteristics, and cycle characteristics can be obtained.

[0162] Furthermore, since both the positive electrode active material layer 1002 and the electrolyte layer 1003 contain the electrolyte 1010, good contact is achieved at the interface between the positive electrode active material layer 1002 and the electrolyte layer 1003. As a result, a secondary battery 1000 can be made with improved rate characteristics, discharge capacity, cycle characteristics, etc.

[0163] The absence or very low amount of organic solvents makes it possible to create a secondary battery that is less prone to ignition and combustion, thus improving safety, which is desirable. Furthermore, if the electrolyte layer 1003 uses an electrolyte 1010 that has no organic solvents or very little organic solvents, it has sufficient strength even without a separator and can electrically insulate the positive and negative electrodes. Because a separator is not required, a secondary battery with high productivity can be created. If the electrolyte 1010 contains inorganic fillers, the strength is further increased, resulting in a secondary battery with even higher safety.

[0164] To obtain an electrolyte 1010 that is free of or contains very little organic solvent, it is preferable that the electrolyte 1010 be thoroughly dried. In this specification, a electrolyte 1010 is considered thoroughly dried if the weight change of the electrolyte 1010 after drying under reduced pressure at 90°C for 1 hour is within 5%.

[0165] The electrolyte layer 1003 may also contain additives such as vinylene carbonate, propane sultone (PS), tert-butylbenzene (TBB), fluoroethylene carbonate (FEC), lithium bis(oxalate) borate (LiBOB), and dinitrile compounds such as succinonitrile and adiponitrile. The concentration of the added material may be, for example, 0.1 wt% to 5 wt% of the total electrolyte layer 1003.

[0166] Nuclear magnetic resonance (NMR), for example, can be used to identify materials such as lithium-ion conductive polymers, lithium salts, binders, and additives contained in secondary batteries. Analysis results from Raman spectroscopy, Fourier transform infrared spectroscopy (FT-IR), time-of-flight secondary ion mass spectrometry (TOF-SIMS), gas chromatography-mass spectrometry (GC / MS), pyrolysis gas chromatography-mass spectrometry (Py-GC / MS), and liquid chromatography-mass spectrometry (LC / MS) may also be used as a basis for determination. It is preferable to suspend the positive electrode active material layer 1002 in a solvent to separate the positive electrode active material 1011 from other materials before subjecting it to analysis such as NMR.

[0167] This embodiment is not limited to the cross-section of the positive electrode shown in Figure 11(B). For example, Figures 12(A), 12(B), 12(C), and 12(D) show cross-sectional views of the positive electrode as an example different from Figure 11(B).

[0168] As the positive electrode of a secondary battery, a binder (resin) is mixed with a current collector 550 such as metal foil and an active material 551 to fix them together. The binder is also called a binding agent. The binder is a polymer material, and if too much binder is included, the proportion of active material in the positive electrode decreases, reducing the discharge capacity of the secondary battery. Therefore, the amount of binder mixed is kept to a minimum. In Figure 12(A), the areas not filled with the positive electrode active material 551, the second active material 552, and acetylene black 553 represent voids or binder.

[0169] Figure 12(A) illustrates acetylene black 553 as a conductive material. Figure 12(A) also shows an example where a second active material 552, with a smaller particle size than the active material 551, is mixed. A high-density positive electrode can be obtained by mixing particles of different sizes. The active material 551 has a core-shell structure. Note that "core" does not refer to the nucleus of the entire particle, but rather to the positional relationship between the center and the outer shell of the particle. "Core" can also be called the core material. For example, the active material 551 uses a first NCM as the core and a second NCM as the shell. The first NCM is LiNi represented by x:y:z=8:1:1 or x:y:z=9:0.5:0.5. x Co y Mn z Using an O2 composite oxide, the second NCM is LiNi represented by x:y:z=1:1:1. x Co y Mn z O2 composite oxides can be used. The atomic ratio of the second NCM is not limited to the above. For example, reducing the nickel ratio compared to the first NCM may produce a similar effect to the above atomic ratio.

[0170] Furthermore, in Figure 12(A), the boundary between the core region and the shell region of the active material 551 is shown as a dotted line inside the active material 551. Although Figure 12(A) shows an example in which the active material 551 is depicted as spherical, it is not particularly limited and may have various shapes. The cross-sectional shape of the active material 551 may be elliptical, rectangular, trapezoidal, triangular, a quadrilateral with rounded corners, or asymmetrical.

[0171] Figure 12(B) shows examples of the active material 551 being illustrated in various shapes. Figure 12(B) shows examples different from those in Figure 12(A).

[0172] Furthermore, in the positive electrode shown in Figure 12(B), graphene 554 is used as the carbon material used as the conductive material.

[0173] Graphene is a carbon material that possesses remarkable electrical, mechanical, and chemical properties, making it promising for applications in various fields, including field-effect transistors and solar cells.

[0174] Figure 12(B) shows a positive electrode active material layer formed on the current collector 550, comprising an active material 551, graphene 554, and acetylene black 553.

[0175] In the step of mixing graphene 554 and acetylene black 553 to obtain an electrode slurry, it is preferable that the weight of the carbon black mixed is 1.5 to 20 times, preferably 2 to 9.5 times, the weight of the graphene.

[0176] Furthermore, when the mixture of graphene 554 and acetylene black 553 is within the above range, the dispersion stability of acetylene black 553 is excellent during slurry preparation, and aggregation is less likely to occur. Also, when the mixture of graphene 554 and acetylene black 553 is within the above range, a higher electrode density can be achieved than in a positive electrode using only acetylene black 553 as the conductive material. By increasing the electrode density, the capacity per unit weight can be increased. Specifically, the density of the positive electrode active material layer measured by gravimetric measurement can be higher than 3.5 g / cc. Moreover, when active material 551 is used as the positive electrode and the mixture of graphene 554 and acetylene black 553 is within the above range, a synergistic effect in achieving a higher capacity secondary battery can be expected, which is preferable.

[0177] These features make it effective as a secondary battery for use in vehicles.

[0178] Increasing the number of rechargeable batteries increases the vehicle's weight, which in turn increases the energy required to move the batteries, making it difficult to extend the driving range. By using high-density rechargeable batteries, the driving range can be extended without significantly changing the vehicle's total weight.

[0179] Furthermore, as the capacity of a vehicle's secondary battery increases, more power is required for charging, making a high charging speed desirable. In addition, regenerative charging, which temporarily generates electricity when the vehicle brakes are applied and then charges the battery, is performed under high-rate charging conditions, so good rate characteristics are required for vehicle secondary batteries.

[0180] By using active material 551 as the positive electrode and optimizing the mixing ratio of acetylene black and graphene, it becomes possible to achieve both high electrode density and the creation of appropriate gaps necessary for ion conduction, thereby obtaining a secondary battery for automotive use with high energy density and good output characteristics.

[0181] Furthermore, in Figure 12(B), the boundary between the core region and the shell region of the active material 551 is shown by a dotted line inside the active material 551. Note that in Figure 12(B), the areas not filled with the active material 551, graphene 554, and acetylene black 553 represent voids or binders. While voids are necessary for solvent penetration, too many voids reduce electrode density, and too few voids prevent solvent penetration. If voids remain after the secondary battery is formed, efficiency will decrease.

[0182] Figure 12(C) illustrates an example of a cathode using carbon nanotube 555 instead of graphene. Figure 12(C) shows a different example from Figure 12(B). Using carbon nanotube 555 prevents aggregation of carbon black such as acetylene black 553 and improves dispersibility.

[0183] In Figure 12(C), the areas not filled with the active material 551, carbon nanotubes 555, and acetylene black 553 represent voids or binders.

[0184] Furthermore, Figure 12(D) illustrates an example of another cathode. Figure 12(D) also shows an example where the active material 551 does not have a core-shell structure. Additionally, Figure 12(D) shows an example where carbon nanotubes 555 are used in addition to graphene 554. Using both graphene 554 and carbon nanotubes 555 prevents aggregation of carbon black such as acetylene black 553, thereby improving dispersibility.

[0185] In Figure 12(D), the areas not filled with the active material 551, carbon nanotubes 555, graphene 554, and acetylene black 553 represent voids or binders.

[0186] A semi-solid secondary battery can be manufactured by using one of the positive electrodes shown in Figures 12(A), 12(B), 12(C), and 12(D), stacking the electrolyte 1010 on top of the positive electrode, and placing the resulting laminate, with the negative electrode stacked on top of the electrolyte 1010, into a container (such as an outer casing or metal can).

[0187] Furthermore, although the above configuration shows an example of a semi-solid secondary battery, it is not particularly limited, and a secondary battery using a solvent may also be used. In the case of a secondary battery using a solvent, the secondary battery is manufactured by placing a laminate, in which a separator is stacked on the positive electrode and a negative electrode is stacked on the separator, into a container (outer shell, metal can, etc.) and filling the container with a solvent.

[0188] Furthermore, in this specification, a polymer electrolyte secondary battery refers to a secondary battery having a polymer in the electrolyte layer between the positive and negative electrodes. Polymer electrolyte secondary batteries include dry (or intrinsic) polymer electrolyte batteries and polymer gel electrolyte batteries. Polymer electrolyte secondary batteries may also be called semi-solid batteries.

[0189] When a semi-solid-state battery is fabricated using active material 551, the semi-solid-state battery becomes a secondary battery with a large charge / discharge capacity. Furthermore, it can be a semi-solid-state battery with a high charge / discharge voltage. Alternatively, it can be a semi-solid-state battery that is safe and highly reliable.

[0190] This embodiment can be freely combined with other embodiments.

[0191] (Embodiment 5) In this embodiment, examples of vehicles, electronic devices, and buildings having a storage battery according to one aspect of the present invention will be described using Figures 13(A) to 16(B).

[0192] Examples of electronic devices that utilize rechargeable batteries include television equipment (also called televisions or television receivers), monitors for computers, digital cameras, digital video cameras, digital photo frames, mobile phones (also called mobile phones or mobile phone devices), portable game consoles, personal digital assistants, sound playback devices, and large game machines such as pachinko machines.

[0193] Furthermore, storage batteries can be applied to mobile devices, typically automobiles. Examples of automobiles include next-generation clean energy vehicles such as hybrid vehicles (HV), electric vehicles (EV), or plug-in hybrid vehicles (PHEV or PHV), and storage batteries can be applied as one of the power sources installed in these vehicles. Mobile devices are not limited to automobiles. For example, examples of mobile devices include trains, monorails, ships, flying vehicles (helicopters, unmanned aerial vehicles (drones), airplanes, rockets), electric bicycles, electric motorcycles, etc., and storage batteries according to one aspect of the present invention can be applied to these mobile devices.

[0194] Furthermore, the battery of this embodiment may be applied to a ground-mounted charging device installed in a residence, or to a charging station installed in a commercial facility.

[0195] First, Figure 13(A) shows an example of applying the storage battery described in part of Embodiment 1 to an electric vehicle (EV).

[0196] Electric vehicles are equipped with a first battery 1301 as the main drive battery and a second battery 1311 that supplies power to an inverter 1312 that starts the motor 1304. The second battery 1311 is also called a cranking battery or starter battery. The second battery 1311 only needs to have high output, and does not need to have a large capacity, so the capacity of the second battery 1311 is smaller than that of the first battery 1301.

[0197] With regard to the secondary battery of the first storage battery 1301, the above-mentioned Embodiment 1 can be considered.

[0198] In this embodiment, an example is shown in which there is one first storage battery 1301, but multiple batteries may be connected in parallel. By configuring multiple first storage batteries 1301, a large amount of power can be extracted. Multiple first storage batteries 1301 may be connected in parallel, connected in series, or connected in parallel and then further connected in series. Multiple first storage batteries 1301 are also called a battery pack.

[0199] Furthermore, the first battery 1301 installed in the automobile has a service plug or circuit breaker that can disconnect electrical connections with other batteries, etc., without the use of tools.

[0200] Furthermore, the power from the first battery 1301 is mainly used to rotate the motor 1304, but it also supplies power to 42V onboard components (electric power steering 1307, heater 1308, defogger 1309, etc.) via the DC-DC circuit 1306. If there is a rear motor 1317 on the rear wheels, the first battery 1301 is also used to rotate the rear motor 1317.

[0201] Furthermore, the second battery 1311 supplies power to 14V automotive components (audio system 1313, power windows 1314, lights 1315, etc.) via the DC-DC circuit 1310.

[0202] Furthermore, the first battery 1301 is electrically connected to the control circuit unit 1320.

[0203] Furthermore, the control circuit unit 1320 may also use a memory circuit that includes a transistor made of an oxide semiconductor. A charging control circuit or battery control system having a memory circuit that includes a transistor made of an oxide semiconductor may be referred to as a BTOS (Battery operating system or Battery oxide semiconductor).

[0204] It is preferable to use a metal oxide that functions as an oxide semiconductor. For example, as the metal oxide, it is preferable to use a metal oxide such as In-M-Zn oxide (where element M is one or more selected from aluminum, gallium, yttrium, copper, vanadium, beryllium, boron, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, or magnesium). In particular, it is preferable that the In-M-Zn oxide applicable as the metal oxide is CAAC-OS (C-Axis Aligned Crystal Oxide Semiconductor) or CAC-OS (Cloud-Aligned Composite Oxide Semiconductor). Alternatively, In-Ga oxide or In-Zn oxide may be used as the metal oxide. CAAC-OS is an oxide semiconductor having multiple crystalline regions, in which the c-axis of these crystalline regions is oriented in a specific direction. The specific direction refers to the thickness direction of the CAAC-OS film, the normal direction to the surface on which the CAAC-OS film is formed, or the normal direction to the surface of the CAAC-OS film. Furthermore, a crystalline region is a region in which the atomic arrangement has periodicity. If the atomic arrangement is considered as a lattice arrangement, then a crystalline region is also a region in which the lattice arrangement is aligned. In addition, CAAC-OS has regions in which multiple crystalline regions are connected in the ab-plane direction, and these regions may have distortion. Distortion refers to a point in a region in which multiple crystalline regions are connected where the orientation of the lattice arrangement changes between a region in which the lattice arrangement is aligned and another region in which the lattice arrangement is aligned. In other words, CAAC-OS is an oxide semiconductor that is c-axis oriented and does not have a clear orientation in the ab-plane direction. Furthermore, CAC-OS is a material in which, for example, the elements constituting the metal oxide are unevenly distributed in sizes of 0.5 nm to 10 nm, preferably 1 nm to 3 nm, or close to that size. In the following, in a metal oxide, a state in which one or more metal elements are unevenly distributed, and the regions containing the metal elements are mixed in a size of 0.5 nm to 10 nm, preferably 1 nm to 3 nm, or close to that size, is also referred to as a mosaic or patchy state.

[0205] Furthermore, CAC-OS is a composite metal oxide having a mosaic-like structure formed by the separation of the material into a first region and a second region, with the first region distributed within the film (hereinafter also referred to as a cloud-like structure). In other words, CAC-OS is a composite metal oxide having a structure in which the first region and the second region are mixed.

[0206] Here, the atomic ratios of In, Ga, and Zn to the metal elements constituting the CAC-OS in In-Ga-Zn oxide are denoted as [In], [Ga], and [Zn], respectively. For example, in the CAC-OS of In-Ga-Zn oxide, the first region is the region where [In] is greater than the [In] in the composition of the CAC-OS film. The second region is the region where [Ga] is greater than the [Ga] in the composition of the CAC-OS film. Alternatively, for example, the first region is the region where [In] is greater than the [In] in the second region, and [Ga] is smaller than the [Ga] in the second region. Furthermore, the second region is the region where [Ga] is greater than [Ga] in the first region, and [In] is smaller than [In] in the first region.

[0207] Specifically, the first region described above is a region whose main components are indium oxide, indium zinc oxide, etc. The second region described above is a region whose main components are gallium oxide, gallium zinc oxide, etc. In other words, the first region can be rephrased as a region whose main component is In. Similarly, the second region can be rephrased as a region whose main component is Ga.

[0208] Furthermore, a clear boundary may not be observed between the first region and the second region described above.

[0209] For example, in the case of CAC-OS in In-Ga-Zn oxide, EDX mapping obtained using EDX confirms that it has a structure in which regions mainly composed of In (first region) and regions mainly composed of Ga (second region) are unevenly distributed and mixed.

[0210] When CAC-OS is used in a transistor, the conductivity due to the first region and the insulation due to the second region work complementaryly to give CAC-OS a switching function (on / off function). In other words, CAC-OS has conductive function in some parts of the material, insulating function in other parts of the material, and semiconductor function as a whole. By separating the conductive and insulating functions, both functions can be maximized. Therefore, by using CAC-OS in a transistor, high on-current (Ion), high field-effect mobility (μ), and good switching operation can be achieved.

[0211] Oxide semiconductors can take on diverse structures, each possessing different properties. One embodiment of the present invention may include two or more of the following: amorphous oxide semiconductors, polycrystalline oxide semiconductors, a-like OS, CAC-OS, nc-OS, and CAAC-OS.

[0212] Furthermore, since it can be used in high-temperature environments, it is preferable that the control circuit unit 1320 uses a transistor made of an oxide semiconductor. To simplify the process, the control circuit unit 1320 may also be formed using a unipolar transistor. Transistors using an oxide semiconductor in the semiconductor layer have an operating ambient temperature range of -40°C to 150°C, which is wider than that of single-crystal Si, and even if the secondary battery overheats, the change in characteristics is smaller compared to single crystal. The off-current of a transistor using an oxide semiconductor is below the lower limit of measurement regardless of temperature, but the off-current characteristics of a single-crystal Si transistor are highly temperature-dependent. For example, at 150°C, the off-current of a single-crystal Si transistor increases, and the current on / off ratio does not become sufficiently large. The control circuit unit 1320 can contribute to eliminating accidents such as fires caused by secondary batteries.

[0213] The control circuit unit 1320, which uses a memory circuit including an oxide semiconductor transistor, can also function as an automatic control device for secondary batteries to address causes of instability such as micro-shorts. Functions to eliminate causes of instability include overcharging prevention, overcurrent prevention, overheating control during charging, maintaining cell balance in the battery pack, over-discharge prevention, remaining charge indicator, automatic control of charging voltage and current according to temperature, charging current control according to the degree of degradation, detection of abnormal behavior of micro-shorts, and prediction of abnormalities related to micro-shorts. The control circuit unit 1320 has at least one of these functions. Furthermore, it is possible to miniaturize the automatic control device for secondary batteries.

[0214] Furthermore, a micro-short refers to a tiny short circuit inside a secondary battery. It does not mean that the positive and negative electrodes of the secondary battery are short-circuited, making charging and discharging impossible. Rather, it refers to a phenomenon where a small short-circuit current flows through a tiny short circuit. Because even a relatively short-circuit in a small area can cause a large voltage change, this abnormal voltage value may affect subsequent abnormality predictions.

[0215] One of the causes of micro-short circuits is said to be that, due to the uneven distribution of the positive electrode active material after multiple charge-discharge cycles, localized current concentration occurs in parts of the positive and negative electrodes, resulting in areas where the electrical insulation between the positive and negative electrodes fails, or micro-short circuits occur due to the generation of by-reactants from side reactions.

[0216] Furthermore, in addition to detecting micro-shorts, the control circuit unit 1320 also detects the terminal voltage of the secondary battery and manages the charging and discharging state of the secondary battery. For example, to prevent overcharging, both the output transistor and the cutoff switch of the charging circuit can be turned off almost simultaneously.

[0217] An example of a block diagram of the control circuit unit 1320 is shown in Figure 13(B).

[0218] The control circuit unit 1320 includes at least a switch to prevent overcharging, a switch unit 1324 including a switch to prevent over-discharging, a control circuit 1322 that controls the switch unit 1324, and a voltage measurement unit for the first storage battery 1301. The control circuit unit 1320 has set upper and lower voltage limits for the secondary battery used, and limits the current from the outside and the output current to the outside to stay below the upper limits. The range between the lower voltage and upper voltage of the secondary battery is the recommended voltage range for use, and if it falls outside this range, the switch unit 1324 activates and functions as a protection circuit. The control circuit unit 1320 can also be called a protection circuit because it controls the switch unit 1324 to prevent over-discharge and overcharge. For example, if the control circuit 1322 detects a voltage that is likely to cause overcharging, it cuts off the current by turning off the switch of the switch unit 1324. Furthermore, a PTC element may be provided in the charge / discharge path to provide a function to cut off the current in response to the rise in temperature. Furthermore, the control circuit unit 1320 has an external terminal 1325 (+IN) and an external terminal 1326 (-IN).

[0219] The switch section 1324 can be constructed by combining n-channel and p-channel transistors. The switch section 1324 is not limited to switches using Si transistors made of single-crystal silicon, but may also be formed using power transistors made of, for example, Ge (germanium), SiGe (silicon germanium), GaAs (gallium arsenide), GaAlAs (gallium aluminum arsenide), InP (indium phosphide), SiC (silicon carbide), ZnSe (zinc selenide), GaN (gallium nitride), GaOx (gallium oxide; x is a real number greater than 0), etc. Furthermore, since memory elements using OS transistors can be freely arranged by stacking them on circuits using Si transistors, integration can be easily achieved. Also, since OS transistors can be manufactured using the same manufacturing equipment as Si transistors, they can be manufactured at low cost. That is, by stacking a control circuit section 1320 using OS transistors on the switch section 1324 and integrating them, it is possible to create a single chip. This allows for miniaturization as the occupied volume of the control circuit section 1320 can be reduced.

[0220] The first battery 1301 primarily supplies power to 42V (high-voltage) in-vehicle equipment, while the second battery 1311 supplies power to 14V (low-voltage) in-vehicle equipment. Lead-acid batteries are often used for the second battery 1311 due to their cost advantages.

[0221] This embodiment shows an example in which lithium-ion secondary batteries are used for both the first storage battery 1301 and the second storage battery 1311. The second storage battery 1311 may be a lead-acid battery, an inorganic all-solid-state battery, and / or an electric double-layer capacitor.

[0222] Furthermore, the regenerative energy generated by the rotation of the tire 1316 is sent to the motor 1304 via the gear 1305 and charged to the second battery 1311 via the control circuit unit 1321 from the motor controller 1303 and / or the battery controller 1302. Alternatively, it is charged to the first battery 1301 via the control circuit unit 1320 from the battery controller 1302. In order to efficiently charge the regenerative energy, it is desirable that the first battery 1301 be capable of rapid charging.

[0223] The battery controller 1302 can set the charging voltage and charging current of the first storage battery 1301. The battery controller 1302 can set the charging conditions according to the charging characteristics of the secondary battery being used and enable rapid charging.

[0224] Although not shown in the diagram, when connected to an external charger, the charger's outlet or connection cable is electrically connected to the battery controller 1302. Power supplied from the external charger charges the first storage battery 1301 via the battery controller 1302. In some cases, the charger has a control circuit and does not use the functions of the battery controller 1302, but it is preferable to charge the first storage battery 1301 via the control circuit unit 1320 to prevent overcharging. In some cases, the charger's outlet or connection cable may also have a control circuit. The control circuit unit 1320 is sometimes called an ECU (Electronic Control Unit). The ECU is connected to a CAN (Controller Area Network) installed in the electric vehicle. CAN is one of the serial communication standards used as an in-vehicle LAN. The ECU also includes a microcomputer. The ECU also uses a CPU or GPU.

[0225] External chargers installed at charging stations and other locations include 100V outlets, 200V outlets, and 3-phase 200V with 50kW output. Additionally, it is possible to charge by receiving power from external charging equipment using contactless power supply methods.

[0226] For rapid charging, a rechargeable battery capable of withstanding high-voltage charging is desired to achieve short charging times.

[0227] The battery of this embodiment described above comprises a secondary battery that operates at low temperatures and a secondary battery that operates in the medium temperature range. Therefore, it is possible to create a battery that can obtain a stable output even at low temperatures. As a result, by applying this battery, it is possible to create a vehicle that can be driven safely even in cold regions.

[0228] Examples of transport vehicles using one embodiment of the present invention are shown in Figures 14(A), 14(B), 14(C), and 14(D). The automobile 2001 shown in Figure 14(A) is an electric vehicle that uses an electric motor as a power source for driving. Alternatively, it is a hybrid vehicle that can appropriately select and use an electric motor and an engine as power sources for driving. When a secondary battery is mounted on the vehicle, the low-temperature secondary battery, temperature sensor, and heater shown in Embodiment 1 are mounted. Furthermore, a synergistic effect on safety can be obtained by using the semi-solid secondary battery described in Embodiment 5. The automobile 2001 shown in Figure 14(A) has a storage battery 240 described in the previous embodiment. It is also preferable to have a temperature control system for the storage battery 240 that is electrically connected to the storage battery 240.

[0229] Furthermore, the automobile 2001 can be charged by receiving power from an external charging facility via a plug-in method and / or a contactless power supply method, etc., for the secondary battery that the automobile 2001 has. When charging, the charging method and connector specifications may be carried out as appropriate in accordance with the prescribed methods such as CHAdeMO (registered trademark) or Combo. The charging device may be a charging station installed in a commercial facility or a household power supply. For example, the low-temperature secondary battery installed in the automobile 2001 can be charged by supplying power from an external source using plug-in technology. Charging can be performed by converting AC power to DC power via a conversion device such as an AC / DC converter.

[0230] Although not shown in the diagram, the vehicle can also be charged by mounting a power receiving device on the vehicle and receiving power wirelessly from a ground-based power transmission device. In this wireless power supply method, charging can be performed not only when the vehicle is stopped but also while it is in motion by incorporating the power transmission device into the road and / or exterior wall. Furthermore, this wireless power supply method can be used to transmit and receive power between two vehicles. In addition, solar panels can be installed on the exterior of the vehicle to charge the secondary battery when the vehicle is stopped and / or in motion. For such wireless power supply, electromagnetic induction or magnetic resonance methods can be used.

[0231] Figure 14(B) shows a large transport vehicle 2002 equipped with an electrically controlled motor as an example of a transport vehicle. The battery pack 2201 of the transport vehicle 2002 has the storage battery described in the previous embodiment. Since the storage battery has a secondary battery that operates at low temperatures and a secondary battery that operates in the medium temperature range, by applying this storage battery, the transport vehicle 2002 can be made capable of safely operating even in cold regions.

[0232] Figure 14(C) shows, as an example, a large transport vehicle 2003 equipped with an electrically controlled motor. The battery pack 2202 of the transport vehicle 2003 has a maximum voltage of 600V, achieved by connecting more than 100 secondary batteries with voltages of 3.5V to 4.7V in series. Therefore, secondary batteries with small variation in characteristics are required. The battery pack 2202 also has a storage battery as described in the previous embodiment. Since the storage battery has a secondary battery that operates at low temperatures and a secondary battery that operates in the medium temperature range, by applying this storage battery, the transport vehicle 2003 can be made capable of safely operating even in cold regions.

[0233] Figure 14(D) shows an example of an aircraft 2004 having a fuel-burning engine. The aircraft 2004 shown in Figure 14(D) has landing gear for takeoff and landing, and can therefore be considered part of a transport vehicle. The aircraft 2004 has a battery pack 2203, which has a storage battery as described in the previous embodiment.

[0234] The battery of the aircraft 2004 has a maximum voltage of, for example, 32V. By applying the battery according to one aspect of the present invention, an aircraft 2004 that is less affected by the ambient temperature can be obtained.

[0235] An example of applying the battery described in the previous embodiment to a portable battery is shown in Fig. 15(A). The portable battery 700 has a battery 701, a display unit 702, and terminals 703a, 703b, and 703c. By using the battery described in the previous embodiment, a portable battery 700 that can be used even in cold regions can be obtained.

[0236] An example of applying the battery described in the previous embodiment to a stationary power storage system is shown in Fig. 15(B). The stationary power storage system 710 has a battery 711. The stationary power storage system 710 is preferably electrically connected to a commercial power source via a distribution board. By using the battery described in the previous embodiment, a stationary power storage system 710 that can be used even in cold regions can be obtained.

[0237] An example of applying the battery described in the previous embodiment to a solar power generation system is shown in Fig. 15(C). The solar power generation system 715 has a battery 716 and a solar power generation panel 717. The power obtained by the solar power generation panel can be charged into the battery 716. By using the battery described in the previous embodiment, a solar power generation system 715 that can provide a stable power supply even in cold regions can be obtained.

[0238] Next, an example of mounting the battery according to one aspect of the present invention on a building will be described using Figs. 16(A) and 16(B).

[0239] The house shown in Figure 16(A) has a power storage device 2612 having a secondary battery, which is one embodiment of the present invention, and a solar power generation panel 2610. The power storage device 2612 is electrically connected to the solar power generation panel 2610 via wiring 2611, etc. The power storage device 2612 may also be electrically connected to a ground-mounted charging device 2604. The electricity generated by the solar power generation panel 2610 can be used to charge the power storage device 2612. The electricity stored in the power storage device 2612 can be used to charge the secondary battery of the vehicle 2603 via the charging device 2604. The power storage device 2612 is preferably installed in the underfloor space. By installing it in the underfloor space, the space above the floor can be used effectively. Alternatively, the power storage device 2612 may be installed on the floor.

[0240] The power stored in the energy storage device 2612 can also supply power to other electronic devices in the house. Therefore, even when power cannot be supplied from the commercial power source due to a power outage or the like, electronic devices can be used by using the energy storage device 2612 according to one embodiment of the present invention as an uninterruptible power supply. By using the battery described in the previous embodiment in the energy storage device 2612, a stable power supply can be provided even in cold regions.

[0241] Figure 16(B) shows an example of an energy storage device according to one aspect of the present invention. As shown in Figure 16(B), an energy storage device 791 according to one aspect of the present invention is installed in the underfloor space 796 of the building 799.

[0242] The energy storage device 791 is equipped with a control device 790, which is electrically connected by wiring to the distribution board 723, the energy storage controller 725 (also called the control device), the display unit 726, and the router 729.

[0243] Power is supplied from the commercial power supply 721 to the distribution panel 723 via the service drop connection section 730. Power is also supplied to the distribution panel 723 from the energy storage device 791 and the commercial power supply 721, and the distribution panel 723 supplies the supplied power to the general load 727 and the energy storage system load 728 via outlets (not shown).

[0244] General loads 727 are electrical equipment such as televisions and personal computers, while energy storage loads 728 are electrical equipment such as microwave ovens, refrigerators, and air conditioners.

[0245] The energy storage controller 725 includes a measurement unit 731, a prediction unit 732, and a planning unit 733. The measurement unit 731 has the function of measuring the amount of electricity consumed by the general load 727 and the energy storage system load 728 during one day (for example, from 0:00 to 24:00). The measurement unit 731 may also have the function of measuring the amount of electricity consumed by the energy storage device 791 and the amount of electricity supplied from the commercial power supply 721. The prediction unit 732 has the function of predicting the amount of electricity demanded by the general load 727 and the energy storage system load 728 during the next day, based on the amount of electricity consumed by the general load 727 and the energy storage system load 728 during one day. The planning unit 733 has the function of planning the charging and discharging of the energy storage device 791 based on the amount of electricity demand predicted by the prediction unit 732.

[0246] The amount of electricity consumed by the general load 727 and the energy storage system load 728, as measured by the measurement unit 731, can be checked on the display unit 726. It can also be checked on electrical equipment such as televisions and personal computers via the router 729. Furthermore, it can be checked on portable electronic devices such as smartphones and tablets via the router 729. Additionally, the amount of electricity demand for each time period (or hourly) predicted by the prediction unit 732 can be checked on the display unit 726, electrical equipment, and portable electronic devices.

[0247] This embodiment can be used in combination with other embodiments. [Examples]

[0248] In this example, a secondary battery containing an ionic liquid as the electrolyte was fabricated, and its discharge characteristics at low temperatures were evaluated.

[0249] As electrolyte solution 1, an ionic liquid (hereinafter referred to as EMI-FSI) in which the cation is EMI (1-ethyl-3-methylimidazolium) and the anion is FSI (bis(fluorosulfonyl)imide) was mixed with 2.15 mol / L of LiFSI (lithium bis(fluorosulfonyl)imide).

[0250] As electrolyte solution 2, a mixture of EMI-FSI and the cyclic carbonate EC (ethylene carbonate) in a 7:3 (volume ratio) was prepared, and then 2.15 mol / L of LiFSI was added to it.

[0251] As electrolyte solution 3, a mixture of EMI-FSI and the cyclic carbonate FEC (fluoroethylene carbonate) in a 7:3 (volume ratio) was prepared, and then 2.15 mol / L of LiFSI was added to it.

[0252] As electrolyte solution 4, a mixture of EMI-FSI and the linear carbonate DEC (diethyl carbonate) in a 7:3 (volume ratio) was prepared, and then 2.15 mol / L of LiFSI was added to it.

[0253] As electrolyte solution 5, a mixture of EMI-FSI and the linear carbonate EMC (ethyl methyl carbonate) in a 7:3 (volume ratio) was prepared, and then 2.15 mol / L of LiFSI was added to it.

[0254] Lithium nickel-cobalt manganese oxide (manufactured by MTI) was used as the positive electrode active material. Acetylene black (AB) was prepared as the conductive material, and polyvinylidene fluoride (PVDF) was prepared as the binder. A slurry was prepared by mixing the positive electrode active material:AB:PVDF in a weight ratio of 95:3:2, and this slurry was coated onto an aluminum current collector. NMP (N-methyl-2-pyrrolidone) was used as the solvent for the slurry. After coating the current collector with the slurry, the solvent was evaporated. The positive electrode was obtained through the above process.

[0255] The separator was used by laminating polypropylene and glass fiber filter paper (manufactured by Whatman), and polypropylene was arranged on the positive electrode side.

[0256] Lithium metal was prepared for the counter electrode.

[0257] A coin-type half cell was formed using the above electrolytes 1 to 5, the positive electrode, the separator, and the negative electrode.

[0258] Table 1 shows the preparation conditions of electrolytes 1 to 5 and the viscosities at -15°C.

[0259]

Table 1

[0260] For the secondary batteries using electrolytes 1 to 5, charge-discharge tests were conducted at -20°C. The discharge capacities when charged at 0.02C for 50 hours and then discharged at 0.2C for 5 hours are shown in Fig. 17.

[0261] As shown in Fig. 17, electrolyte 1 using only an ionic liquid, and electrolytes 2 and 3 using an ionic liquid and a cyclic carbonate had relatively good discharge capacities. On the other hand, electrolytes 4 and 5 using an ionic liquid and a chain carbonate had a decreased discharge capacity despite having a relatively low viscosity.

[0262] From the above, it became clear that by using only an ionic liquid or an ionic liquid and a cyclic carbonate as the electrolyte, a secondary battery with a relatively high discharge capacity can be obtained even in a low-temperature environment of -20°C. In particular, it became clear that the use of a cyclic carbonate having fluorine results in a high discharge capacity.

Explanation of symbols

[0263] 100 battery 100a battery 100b battery 100c battery 101 Lithium-ion rechargeable battery 101a Lithium-ion rechargeable battery 101b Lithium-ion rechargeable battery 102 Lithium-ion rechargeable battery 102a Lithium-ion rechargeable battery 103 Lithium-ion rechargeable battery 110 Thermal Conductive Materials 111 Container

Claims

1. A storage battery comprising a first lithium-ion secondary battery and a second lithium-ion secondary battery adjacent to each other, and further comprising a temperature sensor, a control circuit, and an inverter, The first lithium-ion secondary battery comprises at least one of an ionic liquid, a molecular crystalline electrolyte, a semi-solid electrolyte, a fully solid electrolyte, and lithium titanate. The second lithium-ion secondary battery has an organic electrolyte, The first lithium-ion secondary battery has a first temperature range as its operating temperature range. The second lithium-ion secondary battery has a second temperature range that includes the upper limit of the first temperature range as its operating temperature range. The lower limit of the first temperature range is lower than the lower limit of the second temperature range. The temperature sensor has the function of detecting the temperature of the second lithium-ion secondary battery. The aforementioned control circuit is If the temperature detected by the temperature sensor is lower than the second temperature range, the first lithium-ion secondary battery is heated by self-generating heat to bring the temperature of the second lithium-ion secondary battery within the second temperature range. The storage battery has a plurality of the first lithium-ion secondary batteries, The aforementioned control circuit is A storage battery having the function of converting the discharge current of one of the first lithium-ion secondary batteries into an alternating current using the inverter when the temperature detected by the temperature sensor is lower than the second temperature range, and repeatedly charging and discharging another of the first lithium-ion secondary batteries using the alternating current.

2. In claim 1, The first lithium-ion secondary battery has the function of a residual heat source, The second lithium-ion secondary battery is a rechargeable battery having the function of starting to discharge to the outside after the temperature has entered the second temperature range.

3. In claim 1 or claim 2, Having a plurality of the aforementioned second lithium-ion secondary batteries, A storage battery in which the number of the first lithium-ion secondary batteries is less than the number of the second lithium-ion secondary batteries.

4. In any one of claims 1 to 3, A storage battery in which the first lithium-ion secondary battery and the second lithium-ion secondary battery are rectangular parallelepipeds, with their largest surfaces facing each other.

5. In claim 4, A storage battery comprising a material with a higher thermal conductivity than air between the first lithium-ion secondary battery and the second lithium-ion secondary battery.

6. In any one of claims 1 to 3, The first lithium-ion secondary battery and the second lithium-ion secondary battery are cylindrical in shape. A storage battery comprising a material with a higher thermal conductivity than air between the first lithium-ion secondary battery and the second lithium-ion secondary battery.

7. In any one of claims 1 to 6, A storage battery having a control circuit that detects at least one of overcharging, over-discharging, or overcurrent, and protects the first lithium-ion secondary battery and the second lithium-ion secondary battery.

8. In any one of claims 1 to 7, The aforementioned organic electrolyte is the first organic electrolyte, The first lithium-ion secondary battery is a storage battery having the ionic liquid and the second organic electrolyte.

9. A vehicle having a storage battery according to any one of claims 1 to 8.

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