Secondary batteries, electronic devices, and vehicles

Abstract

A lithium-ion secondary battery with high capacity and excellent charge-discharge cycle characteristics is provided. A secondary battery with high capacity is provided. A secondary battery with excellent charge-discharge characteristics is provided. A secondary battery in which the degradation of capacity is suppressed even when a state of being charged at high voltage is maintained for a long time is provided. A secondary battery comprising a positive electrode, a negative electrode, an electrolyte, and an outer casing, wherein the positive electrode comprises a positive active material, the positive active material comprises lithium, cobalt, oxygen, magnesium, and fluorine, the number of magnesium atoms included in the positive active material is 0.001 times or more and 0.1 times or less the number of cobalt atoms included in the positive active material, the positive active material has a region having a layered rock salt-type crystal structure, the electrolyte comprises an ionic liquid, and the outer casing comprises a metal layer and a polymer layer laminated on the metal layer, and the polymer layer has a region in contact with the electrolyte.

Description

Technology Field

[0001] One embodiment of the present invention relates to an article, a method, or a method of manufacturing. Alternatively, one embodiment of the present invention relates to a process, a machine, a product, or a composition of matter. One embodiment of the present invention relates to a semiconductor device, a display device, a light-emitting device, a capacitor device, a lighting device, an electronic device, or a method of manufacturing the same. In particular, it relates to a positive electrode active material usable in a secondary battery, a secondary battery, an electronic device having a secondary battery, and a vehicle having a secondary battery.

[0002] Alternatively, one embodiment of the present invention relates to a storage system having a secondary battery and a battery control circuit. Alternatively, one embodiment of the present invention relates to an electronic device and a vehicle having a storage system.

[0003] Furthermore, in this specification, the term "energy storage device" refers to all elements and devices having an energy storage function. Examples include batteries (also referred to as secondary batteries), such as lithium-ion secondary batteries, lithium-ion capacitors, and electric double-layer capacitors.

[0004] Furthermore, in this specification, the term "electronic device" refers to any device having a capacitor, and electro-optical devices having a capacitor, information terminal devices having a capacitor, etc., are all electronic devices. Background Technology

[0005] In recent years, the development of various energy storage devices, such as lithium-ion secondary batteries, lithium-ion capacitors, and air batteries, has been actively underway. In particular, high-output, high-energy-density lithium-ion secondary batteries are in demand for portable information terminals such as mobile phones, smartphones, tablets, and laptop computers, as well as portable music players, digital cameras, medical devices, and next-generation clean energy vehicles (hybrid vehicles (HV), electric vehicles (EV), plug-in hybrid vehicles (PHV), etc.), and have become indispensable in the modern information society as a rechargeable energy source.

[0006] The characteristics required for lithium-ion secondary batteries include improved energy density, improved cycle characteristics, and enhanced safety and long-term reliability in various operating environments.

[0007] Therefore, improvements to cathode active materials are being considered with the goal of enhancing the cycle characteristics and increasing the capacity of lithium-ion secondary batteries (Patent Documents 1 and 2). In addition, research on the crystal structure of cathode active materials is also being conducted (Non-patent Documents 1 to 3).

[0008] Non-patent document 4 describes the physical properties of metal fluorides.

[0009] X-ray diffraction (XRD) is one of the techniques used to interpret the crystal structure of anode active materials. By using the ICSD (Inorganic Crystal Structure Database) introduced in Non-Patent Literature 5, the interpretation of XRD data can be performed. Prior art literature

[0010] Japanese Patent Publication No. JP 2002-216760 Japanese Patent Publication No. JP 2006-261132

[0011] Toyoki Okumura et al, "Correlation of lithium ion distribution and X-ray absorption near-edge structure in O3-and O2-lithium cobalt oxides from first-principle calculation", Journal of Materials Chemistry, 2012, 22, p.17340-17348Motohashi, T. et al, "Electronic phase diagram of the layered cobalt oxide system LixCoO2(0.0≤x≤1.0)", Physical Review B, 80(16); 165114Zhaohui Chen et al, "Staging Phase Transitions in LixCoO2", Journal of The Electrochemical Society, 2002, 149(12) A1604-A1609W. E. Counts et al, "Flouride Model Systems: II, The Binary Systems CaF2-BeF2, MgF2-BeF2, and LiF-MgF2", Journal of the American Ceramic Society, (1953) 36[1] 12-17. Fig.01471Belsky, A. et al., "New developments in the Inorganic Crystal Structure Database(ICSD): accessibility in support of materials research and design", Acta Cryst., (2002) B58 364-369 해결하려는 과제

[0012] One embodiment of the present invention has as its objective to provide a lithium-ion secondary battery with high capacity and excellent charge-discharge cycle characteristics and a method for manufacturing the same. Alternatively, one embodiment of the present invention has as its objective to provide a secondary battery capable of rapid charging and a method for manufacturing the same. Alternatively, one embodiment of the present invention has as its objective to provide a secondary battery with high capacity and a method for manufacturing the same. Alternatively, one embodiment of the present invention has as its objective to provide a secondary battery with excellent charge-discharge characteristics and a method for manufacturing the same. Alternatively, one embodiment of the present invention has as its objective to provide a secondary battery in which the degradation of capacity is suppressed even when a state of being charged at high voltage is maintained for a long time, and a method for manufacturing the same. Alternatively, one embodiment of the present invention has as its objective to provide a secondary battery with high safety or reliability and a method for manufacturing the same. Alternatively, one embodiment of the present invention has as its objective to provide a secondary battery in which the degradation of capacity is suppressed even at high temperatures and a method for manufacturing the same. Alternatively, one embodiment of the present invention has as its objective to provide a secondary battery with a long lifespan and a method for manufacturing the same.

[0013] One embodiment of the present invention has as its objective to provide a secondary battery that is capable of rapid charging, can be used at high temperatures, can increase energy density by increasing the charging voltage, is safe, has a long lifespan, and is of very high quality.

[0014] One embodiment of the present invention has as its objective to provide a positive electrode active material for a lithium-ion secondary battery having high capacity and excellent charge-discharge cycle characteristics, and a method for forming the same. Alternatively, one embodiment of the present invention has as its objective to provide a method for forming a positive electrode active material with high productivity. Alternatively, one embodiment of the present invention has as its objective to provide a positive electrode active material in which the degradation of capacity during charge-discharge cycles is suppressed when used in a lithium-ion secondary battery. Alternatively, one embodiment of the present invention has as its objective to provide a positive electrode active material in which the leaching of transition metals such as cobalt is suppressed even when a state of being charged at a high voltage is maintained for a long time.

[0015] Alternatively, one embodiment of the present invention has as its objective to provide a novel material, active material particles, a capacitor, or a method for manufacturing the same.

[0016] Furthermore, the description of these problems does not interfere with the existence of other problems. Also, one embodiment of the present invention is not required to solve all of these problems. Additionally, problems other than these can be derived from the description of the specification, drawings, and claims. means of solving the problem

[0017] One embodiment of the present invention is a secondary battery having a positive electrode, a negative electrode, an electrolyte, and an outer casing, wherein the positive electrode comprises a positive active material, the positive active material comprises lithium, cobalt, oxygen, magnesium, and fluorine, the number of magnesium atoms included in the positive active material is 0.001 times or more and 0.1 times or less the number of cobalt atoms included in the positive active material, the positive active material has a region having a layered rock salt-type crystal structure, the electrolyte comprises an ionic liquid, and the outer casing has a metal layer and a polymer layer laminated on the metal layer, and the polymer layer has a region in contact with the electrolyte.

[0018] In addition, in the above composition, the ionic liquid comprises an imidazolium cation represented by the general formula (G1), and R 1represents an alkyl group with 1 to 4 carbon atoms, and R 2 to R 4 Each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R 5 It is preferable that the main chain consists of two or more atoms selected from an alkyl group or atoms of C, O, Si, N, S, and P.

[0019] [Chemical Formula 1]

[0020]

[0021] In addition, in the above composition, the ionic liquid comprises a pyridinium cation represented by the general formula (G2), and R 6 represents a main chain composed of two or more atoms selected from an alkyl group or atoms of C, O, Si, N, S, and P, and R 7 to R 11 It is preferable that each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.

[0022] [Chemical Formula 2]

[0023]

[0024] In addition, in the above composition, it is preferable that the ionic liquid contains quaternary ammonium cations.

[0025] In addition, in the above composition, the quaternary ammonium cation is one or more selected from general formula (G4), general formula (G5), and general formula (G6), and R 12 to R 17 and R 18 to R 24It is preferable that each represents independently any of an alkyl group having 1 to 20 carbon atoms, a methoxy group, a methoxymethyl group, a methoxyethyl group, and a hydrogen atom, n and m are 1 to 3, α is 0 to 6, β is 0 to 6, and X or Y represents a straight-chain or branched-chain alkyl group having 1 to 4 carbon atoms, a straight-chain or branched-chain alkoxy group having 1 to 4 carbon atoms, or a straight-chain or branched-chain alkoxyalkyl group having 1 to 4 carbon atoms.

[0026] [Chemical Formula 3]

[0027]

[0028] [Chemical Formula 4]

[0029]

[0030] [Chemical Formula 5]

[0031]

[0032] In addition, in the above composition, the ionic liquid comprises a tertiary sulfonium cation represented by the general formula (G7), and R 25 to R 27 It is preferable that each represents a main chain composed of two or more atoms selected from hydrogen atoms, alkyl groups having 1 to 4 carbon atoms, phenyl groups, or atoms of C, O, Si, N, S, and P, each independently.

[0033] [Chemical Formula 6]

[0034]

[0035] In addition, in the above composition, the ionic liquid comprises a quaternary phosphonium cation represented by the general formula (G8), and R 32 to R 35 It is preferable that each represents a main chain composed of two or more atoms selected from hydrogen atoms, alkyl groups having 1 to 4 carbon atoms, phenyl groups, or atoms of C, O, Si, N, S, and P, each independently.

[0036] [Chemical Formula 7]

[0037]

[0038] Also, in the above composition, (FSO2)2N as the anion of the ionic liquid - or (CF3SO2)2N - It is desirable to include .

[0039] Also, in the above composition, (FSO2)2N as the anion of the ionic liquid - or (CF3SO2)2N - It includes, and it is preferable that the cathode includes graphite.

[0040] Alternatively, one embodiment of the present invention comprises a positive electrode, a negative electrode, an electrolyte, and an outer casing, wherein the positive electrode comprises a positive active material, the positive active material comprises lithium, cobalt, oxygen, magnesium, and fluorine, the positive active material comprises a region having a layered rock salt-type crystal structure, the electrolyte comprises an ionic liquid, the ionic liquid comprises a cation selected from one or more of aromatic cations, quaternary ammonium cations, tertiary sulfonium cations, and quaternary phosphonium cations, the outer casing comprises a metal layer and a polymer layer laminated on the metal layer, the polymer layer comprises a region in contact with the electrolyte, the negative electrode comprises graphite, and when a constant current charge is performed until the battery voltage reaches 4.5V under a 25°C environment and a constant voltage charge is performed until the current value reaches 0.01C, and the positive electrode is analyzed by powder X-ray diffraction using CuKα1 line, 2θ is between 19.10° and 19.50° and 2θ is 45.45° It is a secondary battery having diffraction peaks at 45.65° or lower.

[0041] Also, in the above composition, (FSO2)2N as the anion of the ionic liquid - or (CF3SO2)2N - It is desirable to include .

[0042] Alternatively, one embodiment of the present invention is a secondary battery having a positive electrode, a negative electrode, and an electrolyte, wherein the positive electrode comprises a positive active material, the positive active material comprises lithium, cobalt, and oxygen, and when the temperature during charging is in a range of a first temperature or higher and a second temperature or lower, the upper limit voltage of charging is set to a first value, and when the temperature during charging is at least a second temperature, the upper limit voltage of charging is set to a second value, the first temperature is 5°C or higher and less than 15°C, the second temperature is 25°C or higher and less than 55°C, the first value is 0.02V or higher than the second value, and the first value is 4.45V or higher and 4.6V or lower.

[0043] In addition, in the above composition, it is preferable that the positive active material includes magnesium and fluorine.

[0044] In addition, in the above configuration, it is preferable that the cathode includes graphite.

[0045] Alternatively, one embodiment of the present invention is an electronic device having a secondary battery and a temperature sensor as described in any one of the above.

[0046] Alternatively, one embodiment of the present invention is a vehicle having a secondary battery and a temperature sensor as described in any one of the above. Effects of the invention

[0047] According to one embodiment of the present invention, a lithium-ion secondary battery with high capacity and excellent charge-discharge cycle characteristics and a method for manufacturing the same can be provided. Additionally, according to one embodiment of the present invention, a secondary battery capable of rapid charging and a method for manufacturing the same can be provided. Furthermore, a secondary battery in which the degradation of capacity is suppressed even when a state of being charged at high voltage is maintained for a long time and a method for manufacturing the same can be provided. Additionally, according to one embodiment of the present invention, a secondary battery with high safety or reliability and a method for manufacturing the same can be provided. Additionally, according to one embodiment of the present invention, a secondary battery in which the degradation of capacity is suppressed even at high temperatures and a method for manufacturing the same can be provided. Furthermore, according to one embodiment of the present invention, a secondary battery with a long lifespan and a method for manufacturing the same can be provided.

[0048] According to one embodiment of the present invention, a secondary battery capable of rapid charging, usable at high temperatures, capable of increasing energy density by increasing the charging voltage, safe, long lifespan, and very excellent performance can be provided.

[0049] According to one embodiment of the present invention, a positive electrode active material for a lithium-ion secondary battery having high capacity and excellent charge-discharge cycle characteristics, and a method for forming the same can be provided. Additionally, a method for forming a positive electrode active material with high productivity can be provided. Furthermore, according to one embodiment of the present invention, a positive electrode active material in which the decrease in capacity during charge-discharge cycles is suppressed when used in a lithium-ion secondary battery can be provided. Additionally, according to one embodiment of the present invention, a positive electrode active material in which the leaching of transition metals such as cobalt is suppressed even when a state of being charged at a high voltage is maintained for a long time can be provided.

[0050] Alternatively, one embodiment of the present invention may provide a novel material, active material particles, a capacitor, or a method for producing the same.

[0051] Furthermore, the description of these effects does not interfere with the existence of other effects. Also, one embodiment of the present invention does not necessarily have to possess all of these effects. Additionally, other effects become naturally apparent from the description in the specification, drawings, claims, etc., and other effects can be derived from the description in the specification, drawings, claims, etc. Brief explanation of the drawing

[0052] Figure 1 is a diagram showing an example of a secondary battery. Figure 2 (A) is a diagram showing an example of a cross-section of a secondary battery. Figure 2 (B) is a diagram showing an example of a cross-section of a secondary battery. Figure 3 is a diagram showing an example of a secondary battery. Figure 4 (A) is a diagram showing an example of an electrode. Figure 4 (B) is a diagram showing an example of a method for manufacturing a secondary battery. Figure 4 (C) is a diagram showing an example of a method for manufacturing a secondary battery. Figure 5 (A) is a diagram showing an example of a method for manufacturing a secondary battery. Figure 5 (B) is a diagram showing an example of a method for manufacturing a secondary battery. FIG. 6 (A) is a diagram showing an example of an electrode. FIG. 6 (B) is a diagram showing an example of a method for manufacturing a secondary battery. FIG. 6 (C) is a diagram showing an example of a method for manufacturing a secondary battery. FIG. 6 (D) is a diagram showing an example of a method for manufacturing a secondary battery. FIG. 7 (A) is a diagram showing an example of a secondary battery configuration. FIG. 7 (B) is a diagram showing an example of a secondary battery configuration. FIG. 7 (C) is a diagram showing an example of a secondary battery configuration. Figure 8 is a diagram showing an example of the configuration of a secondary battery. Figure 9 (A) is a diagram showing an example of the configuration of a battery pack. Figure 9 (B) is a diagram showing an example of the configuration of a battery pack. FIG. 10 (A) is a diagram showing an example configuration of a battery pack. FIG. 10 (B) is a diagram showing an example configuration of a battery pack. FIG. 10 (C) is a diagram showing an example configuration of a battery pack. FIG. 10 (D) is a diagram showing an example configuration of a battery pack. FIG. 11 (A) is a drawing illustrating a bendable secondary battery. FIG. 11 (B) is a drawing illustrating a bendable secondary battery. FIG. 11 (C) is a drawing illustrating a bendable secondary battery. FIG. 11 (D) is a drawing illustrating a bendable secondary battery. FIG. 11 (E) is a drawing illustrating a bendable secondary battery. Figure 12 (A) is a diagram illustrating the radius of curvature. Figure 12 (B) is a diagram illustrating the radius of curvature. Figure 12 (C) is a diagram illustrating the radius of curvature. Figure 13 (A) is a diagram illustrating the radius of curvature. Figure 13 (B) is a diagram illustrating the radius of curvature. Figure 13 (C) is a diagram illustrating the radius of curvature. Figure 13 (D) is a diagram illustrating the radius of curvature. Figure 14 (A) shows an example of a cylindrical secondary battery. Figure 14 (B) shows an example of a cylindrical secondary battery. Figure 14 (C) shows an example of a plurality of cylindrical secondary batteries. Figure 14 (D) shows an example of a storage system having a plurality of cylindrical secondary batteries. Figure 15 (A) shows an example of the configuration of a battery pack. Figure 15 (B) shows an example of the configuration of a battery pack. Figure 15 (C) shows an example of the configuration of a battery pack. Figure 16 (A) shows an example of the configuration of a battery storage system. Figure 16 (B) shows an example of a method for manufacturing a battery storage system. Figure 16 (C) shows an example of a method for manufacturing a battery storage system. Figure 16 (D) shows an example of a method for manufacturing a battery storage system. Figure 17 (A) is a drawing illustrating an example of a vehicle. Figure 17 (B) is a drawing illustrating an example of a vehicle. Figure 17 (C) is a drawing illustrating an example of a vehicle. Figure 18 (A) is a drawing illustrating an example of a vehicle. Figure 18 (B) is a drawing illustrating an example of a battery storage system. Figure 19 (A) is a drawing illustrating an example of an electronic device. Figure 19 (B) is a drawing illustrating an example of an electronic device. Figure 19 (C) is a drawing illustrating an example of an electronic device. Figure 20 is a drawing illustrating an example of an electronic device. FIG. 21 (A) is a drawing illustrating an example of an electronic device. FIG. 21 (B) is a drawing illustrating an example of an electronic device. FIG. 21 (C) is a drawing illustrating an example of a secondary battery. FIG. 21 (D) is a drawing illustrating an example of an electronic device. FIG. 21 (E) is a drawing illustrating an example of a secondary battery. FIG. 21 (F) is a drawing illustrating an example of an electronic device. FIG. 21 (G) is a drawing illustrating an example of an electronic device. Figure 22 is a diagram illustrating an example of an electronic device. Figure 23 (A) is a drawing illustrating an example of an electronic device. Figure 23 (B) is a drawing illustrating an example of an electronic device. Figure 23 (C) is a drawing illustrating an example of an electronic device. Figure 24 (A) is a diagram showing the cycle characteristics of a secondary battery. Figure 24 (B) is a diagram showing the cycle characteristics of a secondary battery. Figure 25 is a diagram showing the cycle characteristics of a secondary battery. Figure 26 (A) is a diagram showing the charge-discharge curve of a secondary battery. Figure 26 (B) is a diagram showing the charge-discharge curve of a secondary battery. Figure 27 (A) is a diagram showing the charge-discharge curve of a secondary battery. Figure 27 (B) is a diagram showing the charge-discharge curve of a secondary battery. Figure 28 (A) is a diagram showing the charge-discharge curve of a secondary battery. Figure 28 (B) is a diagram showing the charge-discharge curve of a secondary battery. Figure 29 (A) is a diagram showing the charge-discharge curve of a secondary battery. Figure 29 (B) is a diagram showing the charge-discharge curve of a secondary battery. Figure 30 (A) is a diagram showing the charge-discharge curve of a secondary battery. Figure 30 (B) is a diagram showing the charge-discharge curve of a secondary battery. Figure 31 is a diagram showing the charge / discharge curve of a secondary battery. Specific details for implementing the invention

[0053] Embodiments of the present invention will be described in detail below with reference to the drawings. However, it will be readily understood by those skilled in the art that the present invention is not limited to the description below and that its form and details can be varied. Furthermore, the present invention is not to be interpreted as being limited to the description of the embodiments below.

[0054] In addition, crystal planes and orientations in this specification and others are indicated by Miller indices. When indicating crystal planes and orientations, crystallography places a bar above the number; however, due to constraints on application notation, this specification and others may use a minus sign (-) placed before the number instead of a bar. Furthermore, individual orientations representing directions within the crystal are indicated by [], collective orientations representing all equivalent directions by <>, individual planes representing crystal planes by (), and collective planes having equivalent symmetry by {}.

[0055] In this specification and others, segregation refers to a phenomenon in which a certain element (e.g., B) is spatially unevenly distributed in a solid composed of multiple elements (e.g., A, B, C).

[0056] In the present specification and other documents, the surface layer of a particle such as an active material refers to a region extending from the surface to about 10 nm. A surface formed by a crack or a fracture may also be referred to as the surface. Additionally, a region deeper than the surface layer is referred to as the interior.

[0057] In the present specification and others, the layered rock salt-type crystal structure having a composite oxide containing lithium and a transition metal refers to a crystal structure in which cations and anions are arranged alternately in a rock salt-type ionic arrangement, and the transition metal and lithium are regularly arranged to form a two-dimensional plane, thereby enabling two-dimensional diffusion of lithium. In addition, defects such as deficiencies in cations or anions may also be present. Furthermore, strictly speaking, the layered rock salt-type crystal structure may be a structure in which the lattice of the rock salt-type crystal is deformed.

[0058] In addition, the term "rock salt-type crystal structure" in this specification and others refers to a structure in which cations and anions are arranged alternately. Additionally, there may be a deficiency of cations or anions.

[0059] In addition, the pseudo-spinel crystal structure of a composite oxide containing lithium and a transition metal as described in this specification refers to a crystal structure having a space group R-3m, which is not a spinel crystal structure but in which ions such as cobalt and magnesium occupy the oxygen 6th coordination position and the arrangement of cations has symmetry similar to that of a spinel type. Furthermore, in a pseudo-spinel crystal structure, light elements such as lithium may occupy the oxygen 4th coordination position, and in this case as well, the arrangement of ions has symmetry similar to that of a spinel type.

[0060] Furthermore, the pseudo-spinel crystal structure randomly contains Li between the layers, but it can also be described as a crystal structure similar to the CdCl2 type crystal structure. This CdCl2-like crystal structure is obtained when lithium nickelate is charged to a depth of 0.94 (Li 0.06Although it is close to the crystal structure of NiO2, pure lithium cobaltate or layered rock salt-type cathode active materials containing a large amount of cobalt are known not to generally adopt this crystal structure.

[0061] The anions of layered rock salt crystals and rock salt crystals take on a cubic close-packed structure (face-centered cubic lattice structure). It is also presumed that the anions of pseudo-spinel crystals take on a cubic close-packed structure. When they come into contact, there exist crystal planes in which the orientation of the cubic close-packed structure composed of anions aligns. However, since the space group of layered rock salt crystals and pseudo-spinel crystals is R-3m, which is different from the space groups Fm-3m (space group of general rock salt crystals) and Fd-3m (space group of rock salt crystals with the simplest symmetry) of rock salt crystals, the Miller indices of the crystal planes satisfying the above conditions differ between layered rock salt crystals and pseudo-spinel crystals and rock salt crystals. In this specification, in layered rock salt crystals, pseudo-spinel crystals, and rock salt crystals, the state in which the orientation of the cubic close-packed structure composed of anions aligns is sometimes referred to as the crystal orientation being substantially aligned.

[0062] A secondary battery has, for example, a positive electrode and a negative electrode. As a material constituting the positive electrode, there is a positive active material. The positive active material is, for example, a substance that undergoes a reaction contributing to the charge / discharge capacity. Additionally, the positive active material may include a part of a substance that does not contribute to the charge / discharge capacity.

[0063] In the present specification and other documents, a positive active material of one embodiment of the present invention may be described as a positive material or a positive material for a secondary battery. Furthermore, in the present specification and other documents, it is preferable that a positive active material of one embodiment of the present invention comprises a compound. Furthermore, in the present specification and other documents, it is preferable that a positive active material of one embodiment of the present invention comprises a composition. Furthermore, in the present specification and other documents, it is preferable that a positive active material of one embodiment of the present invention comprises a composite.

[0064] (Embodiment 1)

[0065] In this embodiment, an example of a secondary battery of one form of the present invention will be described.

[0066] In secondary batteries, the discharge capacity can be increased by raising the charging voltage. Energy density can also be increased.

[0067] On the other hand, in secondary batteries, increasing the charging voltage can lead to a significant decrease in capacity over charge-discharge cycles. At high charging voltages, for example, the crystal structure of the positive electrode active material may become unstable.

[0068] For example, consider the case where a material containing a metal that acts as a carrier ion (hereinafter referred to as Metal A) is used as the positive electrode active material. Metal A is released from the positive electrode active material during the charging reaction. As the charging voltage is increased, a large amount of Metal A is released from the positive electrode active material, which may cause a significant change in the crystal structure of the positive electrode active material. If the change in the crystal structure due to the insertion and release of Metal A is irreversible, the crystal structure gradually collapses, and a significant decrease in capacity may occur with each charge-discharge cycle.

[0069] A secondary battery using a positive active material of one embodiment of the present invention can suppress the collapse of the crystal structure and suppress the decrease in capacity due to charge-discharge cycles even when charging is repeatedly performed at a high charging voltage.

[0070] Furthermore, as described in the examples below, it was discovered that in a secondary battery using a positive active material of one form of the present invention, by using a positive electrode containing the positive active material of one form of the present invention as the positive electrode and using an ionic liquid as the main solvent of the electrolyte, the decrease in capacity due to charge-discharge cycles is further suppressed and significantly superior characteristics of the secondary battery are realized.

[0071] Ionic liquids are salts composed of a combination of cations and anions. Ionic liquids are sometimes referred to as room temperature molten salts.

[0072] Ionic liquids have low volatility and flammability, and are stable over a wide temperature range. Because they are difficult to volatilize even at high temperatures, they can suppress the expansion of secondary batteries caused by gas generation from the electrolyte. Therefore, the operation of the secondary battery remains stable even at high temperatures. Additionally, they have low flammability and possess flame retardancy.

[0073] By using ionic liquids, it is possible to realize a secondary battery that can be used at high temperatures and has high safety.

[0074] For example, organic solvents such as diethyl carbonate (DEC) and ethyl methyl carbonate (EMC) have a boiling point lower than 150°C and are highly volatile, so when a secondary battery is used at high temperatures, gas is generated and the casing may expand. In addition, organic solvents may have a flash point of 50°C or lower.

[0075] Meanwhile, ionic liquids have low volatility and can be said to be very stable up to temperatures lower than the temperature at which reactions such as decomposition occur, for example, up to about 300°C.

[0076] As mentioned above, it can be seen that ionic liquids are stable even at high temperatures. On the other hand, if other components constituting the secondary battery, such as the positive electrode active material, negative electrode active material, or casing, change at high temperatures, particularly if they change irreversibly, the capacity of the secondary battery may decrease significantly.

[0077] For example, if the crystal structure of the material constituting the positive electrode active material changes irreversibly due to charging at high temperatures, the secondary battery deteriorates significantly. For instance, there may be cases where a significant decrease in capacity occurs with each charge-discharge cycle. When the temperature is high and the charging voltage is also high, the crystal structure of the positive electrode may become more unstable.

[0078] In a secondary battery of one embodiment of the present invention, by using a positive electrode active material having a crystal structure that is highly stable at high charging voltages and high temperatures, excellent characteristics can be realized even at high temperatures and high charging voltages, and the effects of the ionic liquid can be fully exerted. That is, the significant improvement in characteristics obtained by using the configuration of a secondary battery of one embodiment of the present invention is achieved through the combination with the positive electrode active material of one embodiment of the present invention.

[0079] Furthermore, as described below, the positive active material of one embodiment of the present invention preferably comprises element X, and preferably comprises a halogen in addition to element X. It is suggested that by including element X or a halogen in addition to element X in the positive active material of one embodiment of the present invention, the reaction with the ionic liquid on the surface of the positive active material is suppressed. As described above, the ionic liquid is very stable even at high temperatures. Meanwhile, in the secondary battery of one embodiment of the present invention, the reaction potential range is very wide. In such a wide reaction potential range, there are cases where there is concern about the reaction with the ionic liquid on the surface of the active material; therefore, it is suggested that by using the positive active material of one embodiment of the present invention, the reaction with the ionic liquid is suppressed, and a more stable secondary battery is realized.

[0080] By using the configuration of a secondary battery of one embodiment of the present invention, a secondary battery capable of repeatedly performing charging can be realized, for example, even if the upper limit voltage of charging is increased. For example, a secondary battery capable of repeatedly performing charging can be realized by setting the upper limit voltage of charging preferably 4.45V or higher, more preferably 4.47V or higher, even more preferably 4.49V or higher, for example, to about 4.5V. Furthermore, by using the configuration of a secondary battery of one embodiment of the present invention, the decrease in discharge capacity can be significantly suppressed even if the upper limit voltage of charging is increased.

[0081] In the configuration of a secondary battery of one embodiment of the present invention, when the temperature during charging is in the range of t(1)[℃] or higher and less than t(2)[℃], it is preferable to set the upper limit voltage of charging to v(1)[V], and when the temperature during charging is t(2)[℃] or higher, it is preferable to set the upper limit voltage of charging to v(2)[V]. Here, it is preferable that t(1) is a value of 5 or higher and 15 or lower, and it is preferable that t(2) is a value of 25 or higher and less than 55. In addition, it is preferable that v(1) is a value greater than or equal to 0.02 than v(2), and it is preferable that v(1) is a value of 4.45 or higher and 4.6 or lower.

[0082] By using the configuration of a secondary battery of one embodiment of the present invention, a secondary battery capable of repeatedly performing charging at a high charging voltage even at high temperatures of, for example, 42°C or higher can be realized. For example, by setting the ambient temperature to 42°C or higher and setting the upper limit voltage of charging to preferably 4.37V or higher, more preferably 4.40V or higher, even more preferably 4.42V or higher, even more preferably 4.44V or higher, for example, about 4.45V, a secondary battery capable of repeatedly performing charging can be realized.

[0083] In addition, excellent secondary batteries can be realized even at higher temperatures. For example, there are cases where secondary batteries can be realized that operate stably at temperatures between 42°C and 200°C, between 42°C and 180°C, between 42°C and 150°C, between 42°C and 120°C, between 42°C and 100°C, or between 42°C and 90°C.

[0084] A secondary battery of one embodiment of the present invention has a discharge capacity of 160 mAh / g or more after discharging, for example, an accumulated charge of 57,000 mAh / g. Here, for example, it is preferable that the discharge capacity be measured at 0.2C. In addition, it is preferable that the accumulated charge and discharge capacity be calculated per weight of the positive active material.

[0085] In addition, a secondary battery of one embodiment of the present invention has a discharge capacity of 160 mAh / g or more after performing 300 charging cycles at a charging voltage of 4.5 V, for example, at 25°C. Here, for example, it is preferable that the discharge capacity be measured at 0.2 C. In addition, it is preferable that the accumulated charge and discharge capacity be calculated per weight of the positive active material.

[0086] In addition, a secondary battery of one embodiment of the present invention is preferably used in combination with a battery control circuit. The battery control circuit preferably has a function to control charging, for example. Control of charging refers to, for example, monitoring parameters of the secondary battery and changing the charging conditions according to the state. Examples of parameters of the secondary battery to be monitored include the voltage, current, temperature, charge amount, impedance, etc. of the secondary battery.

[0087] In addition, a secondary battery of one form of the present invention is preferably used in combination with a sensor. The sensor preferably has a function capable of measuring one or more of, for example, displacement, position, velocity, acceleration, angular velocity, rotational speed, distance, light, liquid, magnetism, temperature, chemical substances, sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, inclination, vibration, odor, and infrared radiation.

[0088] In addition, in one embodiment of the present invention, it is preferable that the charging of the secondary battery is controlled according to a value measured by a sensor. An example of the control of a secondary battery using a temperature sensor will be described later.

[0089] [Cathode active material]

[0090] Hereinafter, a positive active material preferred for use in a secondary battery of one form of the present invention will be described.

[0091] Structure of the positive active material

[0092] It is preferable that the positive active material includes a metal that serves as a carrier ion (hereinafter, element A). As element A, for example, alkali metals such as lithium, sodium, and potassium, and Group 2 elements such as calcium, beryllium, and magnesium may be used.

[0093] 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, there are more ions contributing to the capacity of the secondary battery, and thus the capacity increases. However, if a large amount of element A is released, the crystal structure of the compound contained in the positive electrode active material becomes prone to collapse. The collapse of the crystal structure of the positive electrode active material may result in a decrease in discharge capacity during charge-discharge cycles. In one embodiment of the present invention, the positive electrode active material may contain element X, thereby suppressing the collapse of the crystal structure when carrier ions are released during the charging of the secondary battery. For example, a portion of element X may substitute for the position of element A. As element X, elements such as magnesium, calcium, zirconium, lanthanum, and barium may be used. Additionally, for example, elements such as copper, potassium, sodium, and zinc may be used as element X. Furthermore, two or more of the aforementioned elements may be used in combination as element X.

[0094] In addition, it is preferable that the positive active material of one embodiment of the present invention includes a halogen in addition to element X. It is preferable to include a halogen such as fluorine or chlorine. When the positive active material of one embodiment of the present invention includes the halogen, the substitution of element X at the position of element A may be promoted.

[0095] In one embodiment of the present invention, when the positive active material comprises element X or comprises a halogen in addition to element X, the electrical conductivity on the surface of the positive active material may be suppressed.

[0096] In addition, a positive electrode active material of one embodiment of the present invention comprises a metal (hereinafter referred to as element M) whose valence changes through the charging and discharging of a secondary battery. Element M is, for example, a transition metal. A positive electrode active material of one embodiment of the present invention comprises, for example, one or more of cobalt, nickel, and manganese as element M, and particularly comprises cobalt. In addition, at the position of element M, an element that does not change valence and can have the same valence as element M, such as aluminum, more specifically, for example, a typical trivalent element, may be included. The aforementioned element X may be substituted at the position of element M, for example. In addition, if the positive electrode active material of one embodiment of the present invention is an oxide, element X may be substituted at the position of oxygen.

[0097] As a positive electrode active material of one embodiment of the present invention, it is preferable to use, for example, a lithium composite oxide having a layered rock salt-type crystal structure. More specifically, as a lithium composite oxide having a layered rock salt-type crystal structure, for example, lithium cobaltate, lithium nickelate, a lithium composite oxide containing nickel, manganese, and cobalt, a lithium composite oxide containing nickel, cobalt, and aluminum, etc., may be used. Furthermore, it is preferable that these positive electrode active materials be represented by space group R-3m.

[0098] In the case of a positive electrode active material having a layered rock salt-type crystal structure, the crystal structure may collapse when the charging depth is increased. Here, the collapse of the crystal structure refers, for example, to the misalignment of layers. If the collapse of the crystal structure is irreversible, the capacity of the secondary battery may decrease with repeated charging and discharging.

[0099] In one embodiment of the present invention, the positive active material includes element X, thereby suppressing the misalignment of the layer even when, for example, the charging depth increases. By suppressing the misalignment, the change in volume due to charging and discharging can be minimized. Therefore, the positive active material of one embodiment of the present invention can realize excellent cycle characteristics. Furthermore, the positive active material of one embodiment of the present invention can maintain a stable crystal structure under a high-voltage charging state. Therefore, the positive active material of one embodiment of the present invention may be less prone to short circuits when maintaining a high-voltage charging state. Such cases are desirable because they further enhance safety.

[0100] In one embodiment of the present invention, the positive active material has a small difference in volume when compared per equal number of transition metal atoms and a change in crystal structure between a sufficiently discharged state and a state charged to high voltage.

[0101] One embodiment of the present invention has a positive active material with the chemical formula AM y O Z There are cases where it is represented as (y>0, z>0). For example, lithium cobaltate is sometimes represented as LiCoO2. Also, for example, lithium nickelate is sometimes represented as LiNiO2.

[0102] When the charge depth is 0.8 or greater, the positive active material of one embodiment of the present invention containing element X is represented by space group R-3m, and although it is not a spinel-type crystal structure, there may be a structure in which ions such as element M (e.g., cobalt) and element X (e.g., magnesium) occupy the oxygen 6th coordination position, and the arrangement of cations has symmetry similar to that of a spinel type. In this specification and other documents, this structure is referred to as a pseudo-spinel-type crystal structure. Furthermore, in a pseudo-spinel-type crystal structure, light elements such as lithium may occupy the oxygen 4th coordination position, and in this case as well, the arrangement of ions has symmetry similar to that of a spinel type.

[0103] When carrier ions detach during charging, the structure of the cathode active material becomes unstable. A pseudo-spinel crystal structure can be described as a structure capable of maintaining high stability even when carrier ions detach.

[0104] In the present invention, when the charging depth is high, by using a positive active material having a pseudo-spinel structure in a secondary battery, for example, when the voltage is 4.57V or higher and less than 4.65V or 4.59V or higher and less than 4.63V, for example, about 4.6V based on the potential of lithium metal, the structure of the positive active material is stabilized and the decrease in capacity due to charging and discharging can be suppressed. In addition, when graphite is used as a negative active material in a secondary battery, for example, when the voltage of the secondary battery is preferably 4.45V or higher and less than 4.6V, more preferably 4.47V or higher and less than 4.55V, even more preferably 4.49V or higher and less than 4.53V, for example, about 4.5V, the structure of the positive active material is stabilized and the decrease in capacity due to charging and discharging can be suppressed.

[0105] Furthermore, the pseudo-spinel crystal structure randomly contains Li between the layers, but it can also be described as a crystal structure similar to the CdCl2 type crystal structure. This CdCl2-like crystal structure is obtained when lithium nickelate is charged to a depth of 0.94 (Li 0.06 Although it is close to the crystal structure of NiO2, pure lithium cobaltate or layered rock salt-type cathode active materials containing a large amount of cobalt are known not to generally adopt this crystal structure.

[0106] The anions of layered rock salt crystals and rock salt crystals take on a cubic close-packed structure (face-centered cubic lattice structure). It is also presumed that the anions of pseudo-spinel crystals take on a cubic close-packed structure. When they come into contact, there exist crystal planes in which the orientation of the cubic close-packed structure composed of anions aligns. However, since the space group of layered rock salt crystals and pseudo-spinel crystals is R-3m, which is different from the space groups Fm-3m (space group of general rock salt crystals) and Fd-3m (space group of rock salt crystals with the simplest symmetry) of rock salt crystals, the Miller indices of the crystal planes satisfying the above conditions differ between layered rock salt crystals and pseudo-spinel crystals and rock salt crystals. In this specification, in layered rock salt crystals, pseudo-spinel crystals, and rock salt crystals, the state in which the orientation of the cubic close-packed structure composed of anions aligns is sometimes referred to as the crystal orientation being substantially aligned.

[0107] The pseudo-spinel crystal structure can have the coordinates of cobalt and oxygen in the unit cell within the range of Co(0, 0, 0.5), O(0, 0, x), and 0.20≤x≤0.25.

[0108] In one embodiment of the positive electrode active material of the present invention, the difference between the volume of a unit cell at a volume with a filling depth of 0 and the volume per unit cell of a pseudo-spinel crystal structure with a filling depth of 0.82 is preferably 2.5% or less, and more preferably 2.2% or less.

[0109] In the pseudo-spinel crystal structure, diffraction peaks appear at 2θ=19.30±0.20° (19.10° to 19.50°) and 2θ=45.55±0.10° (45.45° to 45.65°). More specifically, sharp diffraction peaks appear at 2θ=19.30±0.10° (19.20° to 19.40°) and 2θ=45.55±0.05° (45.50° to 45.60°).

[0110] In addition, the positive electrode active material of one embodiment of the present invention has a pseudo-spinel crystal structure when charged with high voltage, but not all particles necessarily have a pseudo-spinel crystal structure. It may include other crystal structures, and some may be amorphous. However, when Ritfeld analysis is performed on the XRD pattern, it is preferable that the pseudo-spinel crystal structure is 50 wt% or more, more preferable that it is 60 wt% or more, and even more preferable that it is 66 wt% or more. If the pseudo-spinel crystal structure is 50 wt% or more, preferably 60 wt% or more, and more preferably 66 wt% or more, it can be made into a positive electrode active material with sufficiently excellent cycle characteristics.

[0111] The number of atoms of element X is preferably 0.001 times or more and 0.1 times or less the number of atoms of element M, is more preferably greater than 0.01 and less than 0.04, and is more preferably about 0.02. The concentration of element X presented here may be a value obtained by elemental analysis of the entire particle of the cathode active material using, for example, ICP-MS, or may be based on the value of the raw material blending during the formation process of the cathode active material.

[0112] When the element M includes cobalt and nickel, it is preferable that 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 less than 0.1, and more preferable that it is 0.075 or less.

[0113] The positive active material of one embodiment of the present invention is not limited to the materials described above.

[0114] As a positive active material, for example, a complex oxide having a spinel-type crystal structure can be used. In addition, as a positive active material, for example, a polyanionic material can be used. Examples of polyanionic materials include materials having an olivin-type crystal structure and nasicon-type materials. In addition, as a positive active material, for example, a positive material containing sulfur can be used.

[0115] As a material having a spinel-type crystal structure, a composite oxide represented by, for example, LiM2O4 can be used. It is preferable to include Mn as the element M. For example, LiMn2O4 can be used. In addition, it is preferable to include Ni in addition to Mn as the element M, as this can improve the discharge voltage and energy density of the secondary battery. Furthermore, in a lithium-containing material having a spinel-type crystal structure containing manganese, such as LiMn2O4, a small amount of lithium nickelate (LiNiO2 or LiNi 1-x M x It is desirable to improve the characteristics of the secondary battery by mixing O2 (M=Co, Al, etc.).

[0116] As a polyanionic material, for example, a composite oxide containing oxygen, metal A, metal M, and element Z can be used. Metal A is one or more of Li, Na, and Mg, metal M is one or more of Fe, Mn, Co, Ni, Ti, V, and Nb, and element Z is one or more of S, P, Mo, W, As, and Si.

[0117] As a material having an olivine-type crystal structure, for example, a composite material (general formula LiMPO4 (where M is one or more of Fe(II), Mn(II), Co(II), and 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 1 or less, 0 <a<1, 0<b<1), LiFe c Ni d Co ePO4, LiFe c Ni d Mn e PO4, LiNi c Co d Mn e PO4(c+d+e is less than or equal to 1, 0 <c<1, 0<d<1, 0<e<1), LiFe f Ni g Co h Mn i PO4(f+g+h+i is less than or equal to 1, 0 <f<1, 0<g<1, 0<h<1, 0<i<1) 등의 리튬 화합물을 사용할 수 있다.

[0118] Also, general formula Li (2-j) Composite materials such as MSiO4 (M is one or more of Fe(II), Mn(II), Co(II), and Ni(II), 0≤j≤2) can be used. General formula Li (2-j) A representative example of MSiO4 is 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(k+l is 1 or less, 0 <k<1, 0<l<1), Li (2-j) Fe m Ni n Co q SiO4, Li (2-j) Fe m Ni n Mn q SiO4, Li (2-j) Ni m Co n Mn qSiO4(m+n+q is less than or equal to 1, 0 <m<1, 0<n<1, 0<q<1), Li (2-j) Fe r Ni s Co t Mn u SiO4(r+s+t+u is less than or equal to 1, 0 <r<1, 0<s<1, 0<t<1, 0<u<1) 등의 리튬 화합물을 재료로서 사용할 수 있다.

[0119] 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, and Li3Fe2(PO4)3. Additionally, compounds represented by the general formulas Li2MPO4F, Li2MP2O7, and Li5MO4 (M=Fe, Mn) can be used as cathode active materials.

[0120] In addition, as cathode active materials, perovskite-type fluorides such as NaFeF3 and FeF3, metal chalcogenides (sulfides, selenides, tellurides) such as TiS2 and MoS2, oxides having an inverse spinel crystal structure such as LiMVO4, and vanadium oxide-based materials (V2O5, V6O 13 Materials such as LiV3O8, manganese oxide, and organic sulfur compounds may also be used.

[0121] In addition, a borate-based material represented by the general formula LiMBO3 (where M is Fe(II), Mn(II), Co(II)) may be used as the positive active material.

[0122] As a material containing sodium, for example, NaFeO2 or Na 2 / 3 [Fe 1 / 2 Mn 1 / 2 ]O2, Na 2 / 3 [Ni 1 / 3 Mn 2 / 3Sodium-containing oxides such as ]O2, Na2Fe2(SO4)3, Na3V2(PO4)3, Na2FePO4F, NaVPO4F, NaMPO4(M is Fe(II), Mn(II), Co(II), Ni(II)), Na2FePO4F, Na4Co3(PO4)2P2O7 may be used as the positive electrode active material.

[0123] In addition, lithium-containing metal sulfides may be used as the positive electrode active material. Examples include Li2TiS3 and Li3NbS4.

[0124] As a positive electrode active material of one embodiment of the present invention, two or more of the materials described above may be mixed and used.

[0125] In conventional secondary batteries, as the charging voltage increases, the structure of the positive electrode active material becomes unstable, and element M contained in the positive electrode active material may leach into the electrolyte. The leaching of element M into the electrolyte may, for example, lead to a decrease in the capacity of the positive electrode. This decrease in the positive electrode capacity results in a decrease in the capacity of the secondary battery. Furthermore, element M leached into the electrolyte may precipitate on the surface of the negative electrode of the secondary battery. Inhibition of the reaction at the negative electrode by the precipitated element M leads to a decrease in the capacity of the secondary battery.

[0126] In a secondary battery using a positive active material of one embodiment of the present invention, since the structure of the positive active material is stable even at a high charging voltage, the leaching of element M contained in the positive active material into the electrolyte can be suppressed.

[0127] [Electrolyte]

[0128] A secondary battery of one embodiment of the present invention preferably comprises an electrolyte. The electrolyte included in a secondary battery of one embodiment of the present invention preferably comprises an ionic liquid and a salt comprising a metal that serves as a carrier ion.

[0129] When the metal acting as the carrier ion is lithium, the salt containing the metal acting as the carrier ion is, for example, LiN(FSO2)2, LiN(CF3SO2)2, LiN(C4F9SO2)(CF3SO2), LiN(C2F5SO2)2, LiC(FSO2)3, LiC(CF3SO2)3, LiC(C2F5SO2)3, LiCF3SO3, LiC4F9SO3, LiAsF6, LiBF4, LiAlCl4, LiSCN, LiBr, LiI, Li2SO4, Li2B 10 Cl 10 , Li2B 12 Cl 12 One type of lithium salt such as LiPF6, LiClO4, etc., or two or more of these may be used in any combination and ratio.

[0130] In particular, metal salts of fluorosulfonic acid anions and fluoroalkylsulfonic acid anions are preferred, and among them (C n F 2n+1 SO2)2N - Metal salts of amide-based anions represented by (n=0 or more and 3 or less) are desirable because they not only have high stability at high temperatures but also high resistance to oxidation and reduction.

[0131] Ionic liquids are composed of cations and anions, and include organic cations and anions. Examples of organic cations used in electrolytes include aromatic cations such as imidazolium cations and pyridinium cations, and aliphatic onium cations such as quaternary ammonium cations, tertiary sulfonium cations, and quaternary phosphonium cations. In addition, examples of anions used in electrolytes include monovalent amide anions, monovalent methide anions, fluorosulfonic acid anions, perfluoroalkylsulfonic acid anions, tetrafluoroborate anions, perfluoroalkylborate anions, hexafluorophosphate anions, or perfluoroalkylphosphate anions.

[0132] In addition, the electrolyte may include, in addition to the ionic liquid, one type of aprotic solvent selected from, for example, ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate, chloroethylene carbonate, vinylene carbonate, γ-butyrolactone, γ-valerolactone, dimethyl carbonate (DMC), DEC, 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 diglaime, acetonitrile, benzonitrile, tetrahydrofuran, sulfolain, sulfone, etc., or an aprotic solvent selected by mixing two or more of these in any combination and ratio.

[0133] In addition, additives such as vinylene carbonate (VC), propane sulfone (PS), tert-butylbenzene (TBB), fluoroethylene carbonate (FEC), lithium bis(oxalate)borate (LiBOB), succinonitrile, adiponitrile, fluorobenzene, cyclohexylbenzene, and dinitrile compounds such as biphenyl may be added to the electrolyte. The concentration of the added material may be, for example, 0.1 wt% or more and 5 wt% or less with respect to the total solvent.

[0134] As an ionic liquid containing imidazolium cations, for example, an ionic liquid represented by the following general formula (G1) may be used. In general formula (G1), R 1 represents an alkyl group with 1 to 4 carbon atoms, and R 2 to R 4 Each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R 5 represents a main chain composed of two or more atoms selected from an alkyl group, or atoms of C, O, Si, N, S, and P. Also, R 5 Substituents may be introduced into the main chain of the. Examples of introduced substituents include alkyl groups, alkoxy groups, etc.

[0135] [Chemical Formula 8]

[0136]

[0137] As an ionic liquid containing pyridinium cations, for example, an ionic liquid represented by the following general formula (G2) may be used. In general formula (G2), R 6 represents a main chain composed of two or more atoms selected from an alkyl group or atoms of C, O, Si, N, S, and P, and R 7 to R 11 Each represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms independently. Also, R 6 Substituents may be introduced into the main chain of the. Examples of introduced substituents include alkyl groups, alkoxy groups, etc.

[0138] [Chemical Formula 9]

[0139]

[0140] As an ionic liquid containing quaternary ammonium cations, for example, an ionic liquid represented by the following general formulas (G3, G4, G5, and G6) may be used.

[0141] [Chemical Formula 10]

[0142]

[0143] In the general formula (G3), R 28 to R 31 Each represents independently any of an alkyl group, a methoxy group, a methoxymethyl group, a methoxyethyl group, and a hydrogen atom having 1 to 20 carbon atoms.

[0144] [Chemical Formula 11]

[0145]

[0146] In the general formula (G4), R 12 to R 17Each represents independently any of an alkyl group, a methoxy group, a methoxymethyl group, a methoxyethyl group, and a hydrogen atom having 1 to 20 carbon atoms.

[0147] [Chemical Formula 12]

[0148]

[0149] In the general formula (G5), R 18 to R 24 Each represents independently any of an alkyl group, a methoxy group, a methoxymethyl group, a methoxyethyl group, and a hydrogen atom having 1 to 20 carbon atoms.

[0150] [Chemical Formula 13]

[0151]

[0152] In the general formula (G6), n and m are 1 or greater and 3 or less. α is 0 or greater and 6 or less, where n is 1, α is 0 or greater and 4 or less, where n is 2, α is 0 or greater and 5 or less, and where n is 3, α is 0 or greater and 6 or less. β is 0 or greater and 6 or less, where m is 1, β is 0 or greater and 4 or less, where m is 2, β is 0 or greater and 5 or less, and where m is 3, β is 0 or greater and 6 or less. Also, “α or β is 0” indicates non-substitution. Also, cases where both α and β are 0 are excluded. X or Y represents a substituent that is a straight-chain or branched-chain alkyl group having 1 to 4 carbon atoms, a straight-chain or branched-chain alkoxy group having 1 to 4 carbon atoms, or a straight-chain or branched-chain alkoxyalkyl group having 1 to 4 carbon atoms.

[0153] As an ionic liquid containing a tertiary sulfonium cation, for example, an ionic liquid represented by the following general formula (G7) may be used. In general formula (G7), R 25 to R 27 Each represents independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a phenyl group. Or R25 to R 27 As such, a main chain composed of two or more atoms selected from C, O, Si, N, S, and P may be used.

[0154] [Chemical Formula 14]

[0155]

[0156] As an ionic liquid containing a quaternary phosphonium cation, for example, an ionic liquid represented by the following general formula (G8) may be used. In general formula (G8), R 32 to R 35 Each represents independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a phenyl group. Or R 32 to R 35 As such, a main chain composed of two or more atoms selected from C, O, Si, N, S, and P may be used.

[0157] [Chemical Formula 15]

[0158]

[0159] A as shown in general formulas (G1 to G8) - As such, one or more of monovalent amide anions, monovalent methide anions, fluorosulfonic acid anions, perfluoroalkylsulfonic acid anions, tetrafluoroborate anions, perfluoroalkylborate anions, hexafluorophosphate anions, and perfluoroalkylphosphate anions may be used.

[0160] As a monovalent amide anion (C n F 2n+1 SO2)2N - (n=0 to 3) is used, and (CF2SO2)2N is used as the monovalent cyclic amide anion. - Etc. can be used. As a monovalent methane-based anion, (C n F 2n+1 SO2)3C -(n=0 or greater, inclusive) is used, and as a monovalent cyclic methide anion, (CF2SO2)2C - (CF3SO2), etc., can be used. As a fluoroalkylsulfonate anion, (C m F 2m+1 SO3) - Examples include (m=0 or greater, 4 or less). As for fluoroalkylborate anions, {BF n (C m H k F 2m+1-k ) 4-n} - Examples include (n=0 to 3, m=1 to 4, k=0 to 2m), etc. As fluoroalkylphosphate anions, {PF n (C m H k F 2m+1-k ) 6-n} - Examples include (n=0 or greater and 5 or less, m=1 or greater and 4 or less, k=0 or greater and 2m or less).

[0161] In addition, as monovalent amide-based anions, one or more of, for example, bis(fluorosulfonyl)amide anions and bis(trifluoromethanesulfonyl)amide anions may be used.

[0162] In addition, the ionic liquid may contain one or more of hexafluorophosphate anions and tetrafluoroborate anions.

[0163] In the following, (FSO2)2N - The anion represented by is called the FSA anion, and (CF3SO2)2N - There are cases where the anion represented by is referred to as the TFSA anion.

[0164] Specific examples of the cations of the above general formula (G1) include structural formulas (111) to (174).

[0165] [Chemical Formula 16]

[0166]

[0167] [Chemical Formula 17]

[0168]

[0169] [Chemical Formula 18]

[0170]

[0171] [Chemical Formula 19]

[0172]

[0173] [Chemical Formula 20]

[0174]

[0175] [Chemical Formula 21]

[0176]

[0177] Specific examples of the cations of the above general formula (G2) include structural formulas (701) to (719).

[0178] [Chemical Formula 22]

[0179]

[0180] [Chemical Formula 23]

[0181]

[0182] Specific examples of the cations of the above general formula (G4) include structural formulas (501) to (520).

[0183] [Chemical Formula 24]

[0184]

[0185] Specific examples of the cations of the above general formula (G5) include structural formulas (601) to (630).

[0186] [Chemical Formula 25]

[0187]

[0188] [Chemical Formula 26]

[0189]

[0190] Specific examples of the cations of the above general formula (G6) include structural formulas (301) to (309) and structural formulas (401) to (419).

[0191] [Chemical Formula 27]

[0192]

[0193] [Chemical Formula 28]

[0194]

[0195] In addition, in structural formulas (301) to (309) and structural formulas (401) to (419), an example in which m is 1 in the general formula (G6) is shown, but in structural formulas (301) to (309) and structural formulas (401) to (419), m may be changed to 2 or 3.

[0196] In addition, specific examples of the cation of the above general formula (G7) include structural formulas (201) to (215).

[0197] [Chemical Formula 29]

[0198]

[0199] In a secondary battery of one embodiment of the present invention, by using a positive active material of one embodiment of the present invention and including the above-described ionic liquid in the electrolyte, it is possible to suppress the decrease in capacity and realize significantly superior characteristics even when the secondary battery is repeatedly used at a high charging voltage.

[0200] [Cathode active material]

[0201] As a negative electrode active material for a secondary battery, materials capable of performing charge-discharge reactions through the insertion and removal of carrier ions, and materials capable of performing charge-discharge reactions through alloying and dealloying reactions with metal A which becomes a carrier ion, can be used.

[0202] Carbon-based materials such as graphite, digraphitic carbon (soft carbon), nongraphitic carbon (hard carbon), carbon nanotubes, graphene, and carbon black can be used as cathode materials.

[0203] Examples of graphite include synthetic graphite and natural graphite. Examples of synthetic graphite include mesocarbon micro beads (MCMB), coke-based synthetic graphite, and pitch-based synthetic graphite. Among these, spherical graphite having a spherical shape can be used as synthetic graphite. For example, MCMB is desirable because it often has a spherical shape. Additionally, MCMB is preferred because it is relatively easy to reduce its surface area. Examples of natural graphite include flake graphite and spheroidized natural graphite.

[0204] When lithium ions are inserted into graphite (when lithium-graphite interlayer compounds are formed), graphite has a potential as low as that of lithium metal (0.05V to 0.3V vs. Li / Li + For this reason, lithium-ion secondary batteries have a high operating voltage. In other words, for example, the charging voltage of the lithium-ion secondary battery can be increased. Consequently, the energy density of the lithium-ion secondary battery can be increased. In addition, graphite is desirable because it has advantages such as a relatively large capacity per unit volume, relatively small volume expansion, low cost, and higher safety compared to lithium metal.

[0205] In addition, as a negative electrode active material, a material containing at least one of, for example, silicon, tin, gallium, aluminum, germanium, lead, antimony, bismuth, silver, zinc, cadmium, indium, etc. may be used. These elements have a larger capacity than carbon, and in particular, silicon has a high theoretical capacity of 4200 mAh / g. Therefore, it is desirable to use silicon as the negative electrode active material. In addition, compounds containing these elements may 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. Here, elements capable of charge and discharge reactions through alloying and dealloying reactions with lithium, and compounds containing these elements, are sometimes referred to as alloy-based materials.

[0206] In this specification and others, SiO refers, for example, to silicon monoxide. Or SiO refers to SiO x It can also be expressed as follows. Here, it is desirable for x to have a value near 1. Or, for example, x is desirable to be between 0.2 and 1.5, and more desirable to be between 0.3 and 1.2.

[0207] In addition, as negative electrode active materials, titanium dioxide (TiO2) and lithium titanium oxide (Li4Ti5O) 12 ), lithium-graphite interlayer compound (Li x Oxides such as C6), niobium pentoxide (Nb2O5), tungsten oxide (WO2), and molybdenum oxide (MoO2) can be used.

[0208] In addition, as a negative electrode active material, Li having a Li3N type structure, which is a complex nitride of lithium and a transition metal 3-x M x N (M=Co, Ni, Cu) can be used. For example, Li 2.6 Co 0.4Because the N3 has a large charge / discharge capacity (900mAh / g, 1890mAh / cm²) 3 ) It is desirable.

[0209] Using a complex nitride of lithium and a transition metal is desirable because it allows for combination with materials such as V2O5 and Cr3O8, which do not contain lithium ions, as the positive electrode active material, since lithium ions are contained within the negative electrode active material. Furthermore, even when a material containing lithium ions is used as the positive electrode active material, the complex nitride of lithium and a transition metal can be used as the negative electrode active material by removing the lithium ions contained in the positive electrode active material beforehand.

[0210] In addition, materials that undergo a conversion reaction may be used as the negative electrode active material. For example, transition metal oxides that do not alloy with lithium, such as cobalt oxide (CoO), nickel oxide (NiO), and iron oxide (FeO), may be used as the negative electrode active material. Materials that undergo a conversion reaction include oxides such as Fe2O3, CuO, Cu2O, RuO2, and Cr2O3, and CoS2O3. 0.89 There are also 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.

[0211] In conventional secondary batteries, element M contained in the positive electrode active material may leach into the electrolyte and precipitate on the surface of the negative electrode. Inhibition of the reaction at the negative electrode by the precipitated element M leads to a decrease in the capacity of the secondary battery.

[0212] For example, consider the case where graphite is used as a negative electrode active material. In graphite, insertion and removal of carrier ions occur between layers when a battery reaction takes place. For example, insertion and removal of carrier ions occur in the area of ​​the surface of the graphite particles where the cross-section of the layer is exposed. Since the battery reaction occurs efficiently only in specific areas of the particle surface, it is suggested that, for example, the particle surface is more susceptible to the influence of precipitation of element M.

[0213] As described above, in a secondary battery using a positive electrode active material of one embodiment of the present invention, the leaching of element M contained in the positive electrode active material into the electrolyte can be suppressed. Therefore, for example, when graphite is used as a negative electrode active material, a high battery capacity can be maintained even when the secondary battery is used repeatedly at a high charging voltage.

[0214] In addition, by using ionic liquid, there is a possibility that the degradation of graphite due to charging and discharging can be suppressed.

[0215] In addition, in a secondary battery of one embodiment of the present invention, by increasing the concentration of carrier ions included in the electrolyte, the insertion of cations into graphite is suppressed, and the lifespan of the secondary battery is extended.

[0216] In an electrolyte containing an ionic liquid, when lithium ions are used as carrier ions included in the electrolyte, for example, the concentration of the lithium salt is preferably 0.8 mol / L or higher, more preferably 1 mol / L or higher and 2.5 mol / L or lower, and even more preferably 1.2 mol / L or higher and less than 2 mol / L.

[0217] [Example of a secondary battery]

[0218] Figure 1 shows a secondary battery using a film-shaped outer casing as an example of a storage device. If the secondary battery using the film-shaped outer casing has a flexible configuration and is mounted on an electronic device that is flexible in at least part, the secondary battery can also bend to match the deformation of the electronic device.

[0219] FIG. 1 is an external view of a secondary battery (500) that is a secondary battery using a film-type outer body. Also, FIG. 2 (A) and (B) show cross-sections of the parts indicated by dotted lines A1-A2 and B1-B2 in FIG. 1. The secondary battery (500) has a positive electrode (503) having a positive current collector (501) and a positive active material layer (502), a negative electrode (506) having a negative current collector (504) and a negative active material layer (505), a separator (507), an electrolyte (508), and an outer body (509). A separator (507) is installed between the positive electrode (503) and the negative electrode (506) provided inside the outer body (509). Also, the inside of the outer body (509) is filled with an electrolyte (508).

[0220] In the secondary battery (500) shown in FIGS. 1 and 2, the positive lead electrode (510) is ultrasonically bonded to the positive current collector (501) of the positive electrode (503), and the negative lead electrode (511) is ultrasonically bonded to the negative current collector (504) of the negative electrode (506). Additionally, the positive current collector (501) and the negative current collector (504) may also serve as terminals that are electrically contacted with the outside. In that case, lead electrodes may not be used, and the positive current collector (501) and the negative current collector (504) may be arranged so that a portion of them is exposed to the outside from the outer body (509).

[0221] In addition, although the positive lead electrode (510) and the negative lead electrode (511) are arranged on the same side in FIG. 1, the positive lead electrode (510) and the negative lead electrode (511) may be arranged on different sides as shown in FIG. 3. As such, in a secondary battery of one embodiment of the present invention, the lead electrodes can be freely arranged, so the degree of design freedom is high. Therefore, the degree of design freedom of a product using a secondary battery of one embodiment of the present invention can be increased. In addition, the productivity of a product using a secondary battery of one embodiment of the present invention can be increased.

[0222] Exterior

[0223] In the secondary battery (500), for the outer body (509), a film having polymer layers, etc., coated on both sides of a metal thin film, for example, may be used. More specifically, for example, a metal thin film with excellent flexibility such as aluminum, stainless steel, copper, or nickel may be used as the metal thin film, a first polymer layer is provided on the inner surface of the outer body, and a second polymer layer is provided on the outer surface of the outer body, and a film having a three-layer structure of a first polymer layer, a metal thin film on the first polymer layer, and a second polymer layer on the metal thin film may be used. It is preferable that the first polymer layer and the second polymer layer are insulating synthetic resin films. In addition, a thermoplastic resin may be used for the first polymer layer and the second polymer layer, and it is particularly preferable to use a thermoplastic resin for the first polymer layer.

[0224] As the first polymer layer and the second polymer layer, a membrane made of a material that inhibits reaction with an ionic liquid, such as polyethylene, polypropylene, polycarbonate, ionomer, polyamide, polyester, etc., may be used. As a polyamide, nylon may be used, for example.

[0225] In addition, in FIG. 2, as an example, the number of pairs of opposing positive active material layers and negative active material layers is set to 5 pairs, but of course, the number of electrode pairs is not limited to 5 pairs and may be more or fewer. If the number of electrode layers is large, a secondary battery with a larger capacity can be made. Also, if the number of electrode layers is small, a thin and highly flexible secondary battery can be made.

[0226] In the above configuration, the outer body (509) of the secondary battery can be deformed such that the minimum radius of curvature is, for example, 3 mm or more and 30 mm or less, more preferably 3 mm or more and 10 mm or less. The film that is the outer body of the secondary battery is composed of one or two sheets, and in the case of a secondary battery with a laminated structure, the cross-sectional structure of the curved battery is a structure fitted into two curves of the film that is the outer body.

[0227] [Example of a secondary battery manufacturing method]

[0228] Next, an example of a method for manufacturing a secondary battery will be explained.

[0229] First, a cathode (506), a separator (507), and an anode (503) are stacked. Figure 4 (A) is an external view of the anode (503) and the cathode (506). The anode (503) has an anode current collector (501), and an anode active material layer (502) is formed on the surface of the anode current collector (501). Additionally, the anode (503) has an area where the anode current collector (501) is partially exposed (hereinafter referred to as a tab area). The cathode (506) has a cathode current collector (504), and a cathode active material layer (505) is formed on the surface of the cathode current collector (504). Additionally, the cathode (506) has an area where the cathode current collector (504) is partially exposed, i.e., a tab area. The area or shape of the tab areas of the anode and the cathode are not limited to the example shown in Figure 4 (A).

[0230] In FIG. 4 (B), stacked cathodes (506), separators (507), and anodes (503) are shown. Here, an example is shown using five cathodes and four anodes. Next, the tab regions of the anodes (503) are joined together, and the tab region of the anode located on the outermost surface is joined to the anode lead electrode (510). For joining, for example, ultrasonic welding is used. Likewise, the tab regions of the cathodes (506) are joined together, and the tab region of the cathode located on the outermost surface is joined to the cathode lead electrode (511).

[0231] Next, a negative electrode (506), a separator (507), and a positive electrode (503) are placed on the outer body (509).

[0232] Next, as shown in (C) of FIG. 4, the outer body (509) is folded at the part indicated by the dashed line. Then, the outer periphery of the outer body (509) is joined. For joining, for example, heat compression may be used. At this time, an area that is not joined (hereinafter referred to as an introduction port) is provided on a part (or one side) of the outer body (509) so that the electrolyte (508) can be introduced later.

[0233] Next, an electrolyte (508) (not shown) is introduced into the interior of the outer body (509) from an inlet provided in the outer body (509). For example, as shown in (A) of FIG. 5, the sealing portion (521) along the first side and the sealing portion (522) along the second side of the outer body (509) are sealed, and the third side is not sealed. Here, in the sealing portion (522), the outer body (509) may be sealed by interposing a bonding layer between the positive lead electrode (510) and the outer body (509) and between the negative lead electrode (511) and the outer body (509), respectively. Next, an electrolyte (508) is introduced from an opening located on the third side. After that, as shown in (B) of FIG. 5, the sealing portion (523) along the third side is sealed. It is preferable to introduce the electrolyte (508) under a reduced pressure atmosphere or an inert atmosphere. Finally, the introduction port is joined. In this way, a laminated secondary battery (500) can be manufactured.

[0234] Next, aging after manufacturing the secondary battery is described. It is desirable to perform aging after manufacturing the secondary battery. An example of aging conditions is described below. First, charging is performed at a rate of 0.001C or higher and 0.2C or lower. The temperature should be, for example, above room temperature and below 50℃. Here, if the reaction potential of the positive or negative electrode exceeds the range of the potential window of the electrolyte (508), the electrolyte may decompose due to the charging and discharging of the secondary battery. If gas is generated when the electrolyte decomposes, and that gas accumulates within the cell, an area is created where the electrolyte cannot come into contact with the electrode surface. That is, the effective reaction area of ​​the electrode is reduced, and the effective resistance increases.

[0235] Furthermore, if the resistance becomes excessively high, the cathode potential decreases, leading to the insertion of lithium into the graphite and, simultaneously, the deposition of lithium on the graphite surface. This lithium deposition can result in a decrease in capacity. For example, if a film or similar substance grows on the surface after lithium has been deposited, the deposited lithium cannot be leached out, resulting in an increase in lithium that does not contribute to capacity. Additionally, if the deposited lithium physically disintegrates and loses conductivity with the electrode, lithium that does not contribute to capacity is also generated. Therefore, it is desirable to vent the gas before the cathode potential reaches the lithium potential due to the increase in charging voltage.

[0236] In addition, after degassing, the charged state may be maintained at a temperature higher than room temperature, preferably between 30°C and 60°C, more preferably between 35°C and 50°C, for example, for 1 hour or more and 100 hours or less. During the initial charging, the electrolyte decomposed on the surface forms a film on the surface of the graphite. Therefore, it is conceivable that the formed film becomes denser by maintaining the temperature higher than room temperature, for example, after degassing.

[0237] [Example of stacking of anode, cathode, and separator]

[0238] Next, various examples of stacking of anodes, cathodes, and separators are described.

[0239] In the configuration shown in FIG. 6 (A), a single separator (123) is folded multiple times so as to be sandwiched between the positive active material layer (122) and the negative active material layer (126). In the configuration shown in FIG. 6 (A), the positive active material layer (122) at the positive electrode (111) is provided on both sides or one side of the positive current collector (121), and the negative active material layer (126) at the negative electrode (115) is provided on both sides or one side of the negative current collector (125). In the configuration shown in FIG. 6 (A), six positive active material layers (122) and negative active material layers (126) face each other with the separator (123) in between, and it is preferable to fold the separator (123) at least five times. Additionally, the separator (123) may be provided to be inserted between the positive active material layer (122) and the negative active material layer (126), or it may be extended to connect a plurality of positive electrodes (111) and negative electrodes (115) into one.

[0240] FIG. 6 (D) shows an example in which a plurality of electrode assemblies are covered by a wound separator. FIG. 6 (B) is a cross-sectional view of the first electrode assembly (130), and FIG. 6 (C) is a cross-sectional view of the second electrode assembly (131). FIG. 6 (D) is a cross-sectional view along the dotted line A1-A2 in FIG. 1. Also, in FIG. 6 (D), the first electrode assembly (130), the second electrode assembly (131), and the separator (123) are shown separately to clarify the drawing.

[0241] As shown in (B) of FIG. 6, in the first electrode assembly (130), a positive electrode (111a) having a positive active material layer (122) on both sides of a positive current collector (121), a separator (123), a negative electrode (115a) having a negative active material layer (126) on both sides of a negative current collector (125), a separator (123), and a positive electrode (111a) having a positive active material layer (122) on both sides of a positive current collector (121) are stacked in this order. Also, as shown in (C) of FIG. 6, in the second electrode assembly (131), a cathode (115a) having a cathode active material layer (126) on both sides of a cathode current collector (125), a separator (123), an anode (111a) having an anode active material layer (122) on both sides of an anode current collector (121), a separator (123), and a cathode (115a) having a cathode active material layer (126) on both sides of a cathode current collector (125) are stacked in this order.

[0242] As shown in (D) of FIG. 6, the secondary battery (500) has a plurality of first electrode assemblies (130) and a plurality of second electrode assemblies (131). Also, as shown in (D) of FIG. 6, the plurality of first electrode assemblies (130) and the plurality of second electrode assemblies (131) are covered with a wound separator (123).

[0243] [Example of a secondary battery 2]

[0244] The wound body (950) shown in (A) of FIG. 7 has a cathode (931), an anode (932), and a separator (933). The wound body (950) is a wound body formed by stacking the cathode (931) and the anode (932) with the separator (933) in between and winding the stacked sheet. Additionally, multiple stacks of the cathode (931), the anode (932), and the separator (933) may be stacked. The number of stacks consisting of the cathode (931), the anode (932), and the separator (933) should be appropriately designed according to the required capacity and the volume of the device.

[0245] As shown in FIG. 7 (B), the secondary battery (913) shown in FIG. 7 (C) can be manufactured by housing the aforementioned wound body (950) in a space formed by joining an outer film (981) and a film (982) having a concave portion by heat pressing or the like. The wound body (950) has terminals (951) and terminals (952) and is impregnated with an electrolyte inside the film (981) and the film (982) having a concave portion. The terminals (951) and terminals (952) are, for example, lead electrodes.

[0246] For the film (981) and the film (982) having a concave portion, the materials and shapes of the outer body (509) presented can be used.

[0247] In addition, although examples using two films are shown in (B) and (C) of FIG. 7, one film may be folded to form a space, and the aforementioned coiled body (950) may be stored in this space.

[0248] In addition, FIG. 8 shows an example in which a prismatic case is used as the housing (930). For example, a prismatic can may be used as the housing (930). Also, the housing (930) may be cylindrical in shape, for example. For the can, for example, the description of the battery can described later may be referenced.

[0249] The coil (950) is impregnated with an electrolyte inside the housing (930). The terminal (952) is in contact with the housing (930), while the terminal (951) is not in contact with the housing (930) because an insulating material is used. Also, in FIG. 8, the housing (930) is shown separated for convenience, but in reality, the coil (950) is covered by the housing (930), and the terminal (951) and terminal (952) extend to the outside of the housing (930). The housing (930) may be made of a metal material (e.g., aluminum) or a resin material.

[0250] [Battery Pack Example 1]

[0251] Figures 9 (A) and (B) are external views of a battery pack. The battery pack has a circuit board (900) and a secondary battery (913). A label (910) is attached to the secondary battery (913). Also, as shown in Figure 9 (B), the secondary battery (913) has terminals (951) and (952). Additionally, the circuit board (900) is fixed with a thread (915).

[0252] The circuit board (900) has a terminal (911) and a battery control circuit (912). The terminal (911) is connected to terminal (951), terminal (952), antenna (914), and battery control circuit (912) through the circuit board (900). Additionally, a plurality of terminals (911) may be provided, and each of the plurality of terminals (911) may be used as a control signal input terminal, a power terminal, etc.

[0253] The battery control circuit (912) may be provided on the back side of the circuit board (900). Additionally, the antenna (914) is not limited to a coil type and may be, for example, linear or plate type. Furthermore, antennas such as planar antennas, aperture antennas, traveling wave antennas, EH antennas, magnetic field antennas, and dielectric antennas may be used. Alternatively, the antenna (914) may be a flat-plate conductor. This flat-plate conductor can function as one of the conductors for electric field coupling. That is, the antenna (914) may function as one of the two conductors of the capacitor. Thus, it is possible to transmit and receive power using an electric field as well as an electromagnetic field and a magnetic field.

[0254] The battery pack has a layer (916) between the antenna (914) and the secondary battery (913). The layer (916) has the function of shielding, for example, the electromagnetic field from the secondary battery (913). For example, a magnetic material can be used as the layer (916).

[0255] In addition, it is desirable for the battery pack to have a temperature sensor.

[0256] Battery Control Circuit

[0257] The battery control circuit (912) can be used as a battery control circuit. It is preferable that the battery control circuit (912) have a charge control circuit. Additionally, the battery control circuit (912) has a switch. The switch can be configured, for example, using a transistor.

[0258] A first transmission path, which is connected to a terminal (951) of a secondary battery (913) and transmits power output from the secondary battery (913), is electrically connected to a terminal of a charging control circuit having a battery control circuit (912). Additionally, a second transmission path connected to a terminal (952) of the secondary battery (913) is electrically connected to a switch provided to the battery control circuit (912). The switch has the function of blocking the second transmission path. The switch controls conduction and blocking operations and can also be described as a switching means for switching between supply and blocking.

[0259] When the battery control circuit (912) detects an abnormality such as a micro-short circuit, the second transmission path can be blocked by inputting a signal to the gate of the switch that blocks the second transmission path. When the second transmission path is blocked, the supply of current from the charger or the supply of current to the mobile device equipped with the secondary battery (913) can be stopped. In addition, by maintaining the signal voltage applied to the gate of the switch that blocks the second transmission path in a memory circuit (including a transistor using an oxide semiconductor), the blockage can be maintained for a long time. Therefore, it can be made into a charging control system with high safety.

[0260] When charging the secondary battery (913) by supplying power from a charger, the secondary battery (913) becomes charged, and the battery control circuit (912) monitors the behavior of voltage or current at the electrode (971) and electrode (972), and if an abnormality is detected, the second transmission path is blocked to stop charging.

[0261] A charger refers to, for example, a device equipped with an adapter connected to an external power source, or a device that performs power transmission using wireless signals. Additionally, chargers may be built into electronic devices such as mobile devices.

[0262] <Example of temperature-based control>

[0263] Next, an example of controlling a secondary battery according to an ambient temperature in one form of the present invention is described. Temperature measurement can be performed using a temperature sensor.

[0264] A secondary battery of one embodiment of the present invention can repeatedly perform charging and discharging at a very high charging voltage. Furthermore, as described in the embodiments below, when the temperature is lower in the secondary battery of one embodiment of the present invention, the secondary battery can be stably and repeatedly operated at a higher charging voltage.

[0265] Below, an example of controlling the charging conditions of a secondary battery according to temperature in one form of the present invention is described.

[0266] If the temperature during charging is in the range of a first temperature or higher and a second temperature or lower, the upper limit voltage of charging is set to the first value. If the temperature during charging is the second temperature or higher, the upper limit voltage of charging is set to the second value.

[0267] The first temperature is, for example, 5°C or higher and less than 15°C, and the second temperature is 25°C or higher and less than 55°C. Or the first temperature is, for example, 8°C or higher and less than 15°C, and the second temperature is 30°C or higher and less than 55°C.

[0268] The first value is 0.02V or higher, 0.04V or higher, 0.06V or higher, or 0.08V or higher than the second value, for example, 0.05V.

[0269] The first value is 4.45V or higher and 4.6V or lower, preferably 4.47V or higher and less than 4.6V, more preferably 4.47V or higher and less than 4.55V, 4.49V or higher and less than 4.53V, and, for example, about 4.5V.

[0270] As described above, by controlling the charging conditions of the secondary battery, the degradation of the secondary battery can be suppressed, thereby extending its lifespan.

[0271] [Battery Pack Example 2]

[0272] In addition, the structure of the battery pack is not limited to Fig. 9.

[0273] For example, as shown in (A) and (B) of FIG. 10, antennas may be provided on each of the opposing pair of surfaces of the secondary battery (913) shown in (A) and (B) of FIG. 9. FIG. 10 (A) is an external view showing one of the pair of surfaces, and FIG. 10 (B) is an external view showing the other of the pair of surfaces. In addition, for parts such as the secondary battery shown in (A) and (B) of FIG. 8, the description of the secondary battery shown in (A) and (B) of FIG. 9 may be appropriately adapted.

[0274] As shown in FIG. 10 (A), an antenna (914) is provided on one of the pair of surfaces of the secondary battery (913) by interposing a layer (916), and as shown in FIG. 10 (B), an antenna (918) is provided on the other of the pair of surfaces of the secondary battery (913) by interposing a layer (917). The layer (917) has the function of shielding, for example, an electromagnetic field from the secondary battery (913). For example, a magnetic material can be used as the layer (917).

[0275] By having the above structure, the size of both the antenna (914) and the antenna (918) can be increased. The antenna (918) has the function of performing data communication with, for example, an external device. For example, an antenna with a shape applicable to the antenna (914) can be applied to the antenna (918). As a communication method between the secondary battery and another device through the antenna (918), a response method that can be used between the secondary battery and another device, such as NFC (Near Field Communication), can be applied.

[0276] Alternatively, as shown in (C) of FIG. 10, a display device (920) may be provided on the secondary battery (913) shown in (A) and (B) of FIG. 9. The display device (920) is electrically connected to the terminal (911). Also, a label (910) may not be provided on the part where the display device (920) is provided. Also, for parts such as the secondary battery shown in (A) and (B) of FIG. 9, the description of the secondary battery shown in (A) and (B) of FIG. 9 may be appropriately adapted.

[0277] The display device (920) may display, for example, an image indicating whether it is charging, an image indicating the amount of charge, etc. As the display device (920), for example, electronic paper, a liquid crystal display, an electroluminescence (also called EL) display, etc., may be used. For example, by using electronic paper, the power consumption of the display device (920) can be reduced.

[0278] Alternatively, as shown in (D) of FIG. 10, a sensor (921) may be provided to the secondary battery (913) shown in (A) and (B) of FIG. 9. The sensor (921) is electrically connected to the terminal (911) through the terminal (922). Also, regarding parts such as the secondary battery shown in (A) and (B) of FIG. 9, the description of the secondary battery shown in (A) and (B) of FIG. 9 may be appropriately adapted.

[0279] The sensor (921) may have the ability to measure, for example, displacement, position, velocity, acceleration, angular velocity, rotational speed, distance, light, liquid, magnetism, temperature, chemical substances, sound, time, longitude, electric field, current, voltage, power, radiation, flow rate, humidity, inclination, vibration, smell, or infrared radiation. By providing the sensor (921), data (such as temperature) regarding the environment in which the secondary battery is placed may be detected, for example, and stored in memory within the battery control circuit (912).

[0280] In addition, examples of the structure of the secondary battery (913) will be explained using (A) to (E) of FIG. 11.

[0281] [Various Composition Examples]

[0282] FIG. 11 (A) is a schematic top view of a bendable secondary battery (250). FIG. 11 (B), (C), (D), and (E) are schematic cross-sectional views at cutting lines C1-C2, C3-C4, A1-A2, and B1-B2, respectively, in FIG. 11 (A). The secondary battery (250) has an outer body (251) and an electrode stack (210) housed inside the outer body (251). The electrode stack (210) has a structure in which at least a positive electrode (211a) and a negative electrode (211b) are stacked. A lead (212a) electrically connected to the positive electrode (211a) and a lead (212b) electrically connected to the negative electrode (211b) extend to the outside of the outer body (251). In addition, in the area enclosed by the outer body (251), an electrolyte (not shown) is sealed in addition to the positive electrode (211a) and the negative electrode (211b). Also, although not shown in (B) of FIG. 11, for example, a separator is placed between the positive electrode (211a) and the negative electrode (211b).

[0283] Next, the exterior body (251) will be described using (B), (C), (D), and (E) of FIG. 11.

[0284] The outer body (251) has a film shape and is folded in half with the positive electrode (211a) and the negative electrode (211b) in between. The outer body (251) has a fold portion (261), a pair of seal portions (262), and a seal portion (263). The pair of seal portions (262) are provided with the positive electrode (211a) and the negative electrode (211b) in between and may be called side seals. Additionally, the seal portion (263) has a portion that overlaps with the lead (212a) and the lead (212b) and may be called top seals.

[0285] It is preferable that the outer body (251) has a wave shape in which ridges (271) and curves (272) are alternately arranged in the portion overlapping the positive electrode (211a) and the negative electrode (211b). Additionally, it is preferable that the seal portion (262) and seal portion (263) of the outer body (251) be flat.

[0286] Fig. 11 (B) shows a cross-section cut at the part overlapping with the ridge (271), and Fig. 11 (C) shows a cross-section cut at the part overlapping with the curve (272). Fig. 11 (B) and (C) both correspond to cross-sections in the width direction of the secondary battery (250), positive electrode (211a), and negative electrode (211b).

[0287] Here, the distance between the end of the negative electrode (211b) in the width direction, that is, the end of the negative electrode (211b) and the seal (262), is defined as distance La. When deformation such as bending is applied to the secondary battery (250), the positive electrode (211a) and the negative electrode (211b) are deformed to be misaligned with each other in the length direction, as will be described later. At this time, if the distance La is excessively short, the outer body (251) and the positive electrode (211a) and the negative electrode (211b) rub against each other strongly, and the outer body (251) may be damaged. In particular, if the metal film of the outer body (251) is exposed, there is a risk that the metal film will be corroded by the electrolyte. Therefore, it is desirable to set the distance La as long as possible. On the other hand, if the distance La is excessively long, the volume of the secondary battery (250) increases.

[0288] In addition, the thicker the total thickness of the stacked anode (211a) and cathode (211b), the longer the distance La between the anode (211a) and cathode (211b) and the seal (262).

[0289] More specifically, when the total thickness of the stacked positive electrode (211a), negative electrode (211b), and unillustrated separator (214) is t, the distance La is preferably 0.8 times or more and 3.0 times or less of the thickness t, more preferably 0.9 times or more and 2.5 times or less, and even more preferably 1.0 times or more and 2.0 times or less. By setting the distance La within this range, a compact battery with high reliability against bending can be realized.

[0290] In addition, when the distance between a pair of seals (262) is set as distance Lb, it is desirable to make the distance Lb sufficiently longer than the width of the positive electrode (211a) and the negative electrode (211b) (here, the width Wb of the negative electrode (211b)). Thus, when deformation such as repeated bending is applied to the secondary battery (250), even if the positive electrode (211a) and the negative electrode (211b) come into contact with the outer body (251), a part of the positive electrode (211a) and the negative electrode (211b) can be misaligned in the width direction, so friction between the positive electrode (211a) and the negative electrode (211b) and the outer body (251) can be effectively prevented.

[0291] For example, it is preferable that the difference between the distance Lb between a pair of seals (262) and the width Wb of the cathode (211b) is 1.6 times or more and 6.0 times or less the thickness t of the anode (211a) and cathode (211b), more preferable that it is 1.8 times or more and 5.0 times or less, and even more preferable that it is 2.0 times or more and 4.0 times or less.

[0292] Also, (D) of FIG. 11 shows a cross-section including a lead (212a) and corresponds to a longitudinal cross-section of a secondary battery (250), a positive electrode (211a), and a negative electrode (211b). As shown in (D) of FIG. 11, it is preferable to have a space (273) between the longitudinal ends of the positive electrode (211a) and the negative electrode (211b) and the outer body (251) at the bend portion (261). The lead (212a) is joined to the positive electrode (211a) in the region (215a).

[0293] Figure 11 (E) is a schematic cross-sectional view of the secondary battery (250) when bent. Figure 11 (E) corresponds to the cross-section at the cutting line B1-B2 in Figure 11 (A).

[0294] When the secondary battery (250) is bent, a portion of the outer body (251) located on the outer side of the bend is deformed to extend, while another portion located on the inner side is deformed to contract. More specifically, the portion located on the outer side of the outer body (251) is deformed so that the amplitude of the wave becomes smaller and the period of the wave becomes larger. Meanwhile, the portion located on the inner side of the outer body (251) is deformed so that the amplitude of the wave becomes larger and the period of the wave becomes smaller. When the outer body (251) is deformed in this way, the stress applied to the outer body (251) due to the bend is relieved, so the material constituting the outer body (251) itself does not need to be stretched. Therefore, the secondary battery (250) can be bent with a small force without damaging the outer body (251).

[0295] Additionally, as shown in (E) of FIG. 11, when the secondary battery (250) is bent, the positive electrode (211a) and the negative electrode (211b) are each misaligned relative to each other. At this time, since one end of the multiple stacked positive electrodes (211a) and negative electrodes (211b) on the side of the seal (263) is fixed by a fixing member (217), they are each misaligned such that the degree of misalignment increases as they get closer to the bending part (261). Therefore, since the stress applied to the positive electrode (211a) and the negative electrode (211b) is relieved, there is no need for the positive electrode (211a) and the negative electrode (211b) themselves to be stretched. Thus, the secondary battery (250) can be bent without damaging the positive electrode (211a) and the negative electrode (211b).

[0296] Additionally, by having a space (273) between the positive electrode (211a) and the negative electrode (211b) and the outer body (251), the positive electrode (211a) and the negative electrode (211b) located on the inside when bent can be relatively offset without coming into contact with the outer body (251).

[0297] The radius of curvature of a surface is explained using FIG. 12 (A), (B), and (C). In FIG. 12 (A), a portion of the curve (1702) included in the surface (1700) is approximated as an arc on a plane (1701) that cuts the surface (1700), the radius of the circle is set as the radius of curvature (1703), and the center of the circle is set as the center of curvature (1704). FIG. 12 (B) is a top view of the surface (1700). FIG. 12 (C) is a cross-sectional view of the surface (1700) cut along the plane (1701). When the surface is cut along the plane, the radius of curvature of the curve appearing in the cross-section varies depending on the angle of the plane relative to the surface or the cutting position, but in this specification, the smallest radius of curvature is defined as the radius of curvature of the surface.

[0298] When a secondary battery is bent by sandwiching an electrode, electrolyte, etc. (1805) between two films that form an outer body, the radius of curvature (1802) of the film (1801) closer to the center of curvature (1800) of the secondary battery is smaller than the radius of curvature (1804) of the film (1803) further from the center of curvature (1800) (Fig. 13 (A)). When the secondary battery is bent to form an arc shape in cross-section, compressive stress is applied to the surface of the film closer to the center of curvature (1800), and tensile stress is applied to the surface of the film further from the center of curvature (1800) (Fig. 13 (B)). If a pattern including a concave or convex portion is formed on the surface of the outer body, the effect of strain can be suppressed within an allowable range even if compressive stress or tensile stress is applied in this way. Therefore, the secondary battery can be deformed so that the minimum radius of curvature of the outer body on the side closer to the center of curvature is, for example, 3 mm or more and 30 mm or less, more preferably 3 mm or more and 10 mm or less.

[0299] In addition, the cross-sectional shape of the secondary battery is not limited to a simple arc shape, but can be a shape in which part has an arc, for example, the shape shown in (C) of FIG. 13, a wave shape ((D) of FIG. 13), an S-shape, etc. When the curved surface of the secondary battery has a shape having multiple centers of curvature, the minimum radius of curvature of the side closer to the center of curvature among the two outer bodies can be deformed such that, for example, the radius of curvature of the curved surface with the smallest radius of curvature among the radii of curvature of each of the multiple centers of curvature is 3 mm or more and 30 mm or less, more preferably 3 mm or more and 10 mm or less.

[0300] [Cylindrical secondary battery]

[0301] An example of a cylindrical secondary battery is described with reference to FIG. 14 (A). As shown in FIG. 14 (A), the cylindrical secondary battery (400) has a positive cap (battery lid) (401) on the top surface and a battery can (outer can) (402) on the side and bottom surfaces. These positive cap (401) and battery can (outer can) (402) are insulated by a gasket (insulating packing) (410).

[0302] Figure 14 (B) is a schematic diagram showing a cross-section of a cylindrical secondary battery. The cylindrical secondary battery shown in Figure 14 (B) has a positive cap (battery lid) (601) on the top surface and a battery can (outer can) (602) on the side and bottom surfaces. These positive cap and battery can (outer can) (602) are insulated by a gasket (insulating packing) (610).

[0303] Inside the hollow cylindrical battery can (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. One end of the battery can (602) is closed and the other end is open. For the battery can (602), a metal such as nickel, aluminum, or titanium, or an alloy thereof, or an alloy of a metal other than these (e.g., stainless steel) that is corrosion-resistant to the electrolyte may be used. In addition, it is preferable to coat the battery can (602) with nickel or aluminum, etc., to prevent corrosion caused by the electrolyte. Inside the battery can (602), the battery element in which the positive electrode, negative electrode, and separator are wound is sandwiched between a pair of opposing insulating plates (608, 609). In addition, a non-aqueous electrolyte (not shown) is injected into the interior of the battery can (602) provided with the battery element. As the non-aqueous electrolyte, a coin-type secondary battery can be used.

[0304] Since the positive and negative electrodes used in the cylindrical battery are wound, it is desirable to form active material on both sides of the current collector. A positive terminal (positive current collector lead) (603) is connected to the positive electrode (604), and a negative terminal (negative current collector lead) (607) is connected to the negative electrode (606). Metal materials such as aluminum may be used for the positive terminal (603) and the negative terminal (607), respectively. The positive terminal (603) is resistance welded to the safety valve mechanism (613), and the negative terminal (607) is resistance welded to the bottom of the battery can (602). The safety valve mechanism (613) is electrically connected to the positive cap (601) through a PTC (Positive Temperature Coefficient) element (611). The safety valve mechanism (613) cuts off the electrical connection between the positive cap (601) and the positive electrode (604) when the internal pressure of the battery rises above a predetermined threshold value. In addition, 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 amount of current according to the increase in resistance. Barium titanate (BaTiO3)-based semiconductor ceramics can be used for the PTC element.

[0305] Fig. 14 (C) shows an example of a storage system (415). The storage system (415) has a plurality of secondary batteries (400). The positive electrodes of each secondary battery are in contact with a conductor (424) separated by an insulator (425) and are electrically connected. The conductor (424) is electrically connected to a control circuit (420) through wiring (423). Additionally, the negative electrodes of each secondary battery are electrically connected to a control circuit (420) through wiring (426). As the control circuit (420), the battery control circuit (912) described above may be applied.

[0306] Fig. 14 (D) shows an example of a storage system (415). The storage system (415) has a plurality of secondary batteries (400), and the plurality of secondary batteries (400) are sandwiched between a conductive plate (413) and a conductive plate (414). The plurality of secondary batteries (400) are electrically connected to the conductive plate (413) and the conductive plate (414) by wiring (416). The plurality of secondary batteries (400) may be connected in parallel, may be connected in series, or may be connected in series after being connected in parallel. By configuring a storage system (415) having a plurality of secondary batteries (400), a large amount of power can be extracted.

[0307] Multiple secondary batteries (400) may be connected in parallel and then connected in series.

[0308] A temperature control device may be provided between multiple secondary batteries (400). When a secondary battery (400) is overheated, it may be cooled by the temperature control device, and when a secondary battery (400) is excessively cooled, it may be heated by the temperature control device. Therefore, the performance of the storage system (415) is less likely to be affected by the ambient temperature.

[0309] In addition, in (D) of FIG. 14, the storage system (415) is electrically connected to the control circuit (420) through wiring (421) and wiring (422). Wiring (421) is electrically connected to the positive electrode of a plurality of secondary batteries (400) through a conductive plate (413), and wiring (422) is electrically connected to the negative electrode of a plurality of secondary batteries (400) through a conductive plate (414).

[0310] [Battery Pack Example 3]

[0311] Next, an example of a capacitor system of one form of the present invention will be described using FIG. 15.

[0312] FIG. 15 (A) is a drawing showing the appearance of a secondary battery pack (531). FIG. 15 (B) is a drawing explaining the configuration of the secondary battery pack (531). The secondary battery pack (531) has a circuit board (540) and a secondary battery (513). A label (529) is attached to the secondary battery (513). The circuit board (540) is fixed by a thread (515). In addition, the secondary battery pack (531) has an antenna (517).

[0313] In the secondary battery pack (531), a control circuit (590) is provided on a circuit board (540), as shown in (B) of FIG. 15, for example. The circuit board (540) is also electrically connected to a terminal (514). Additionally, the circuit board (540) is electrically connected to an antenna (517), one of the positive and negative leads (551) of the secondary battery (513), and the other of the positive and negative leads (552). The battery control circuit (912) described above can be applied as the control circuit (590).

[0314] Alternatively, as shown in (C) of FIG. 15, there may be a circuit system (590a) provided on a circuit board (540) and a circuit system (590b) electrically connected to the circuit board (540) through a terminal (514). For example, a portion of a control circuit of one form of the present invention is provided on the circuit system (590a), and another portion is provided on the circuit system (590b).

[0315] In addition, the antenna (517) is not limited to a coil type and may be, for example, linear or plate type. Also, antennas such as planar antennas, aperture antennas, traveling wave antennas, EH antennas, magnetic field antennas, and dielectric antennas may be used. Alternatively, the antenna (517) may be a flat-plate conductor. This flat-plate conductor can function as one of the conductors for electric field coupling. That is, the antenna (517) may function as one of the two conductors of the capacitor. Thus, it is possible to transmit and receive power using an electric field as well as an electromagnetic field and a magnetic field.

[0316] The secondary battery pack (531) has a layer (519) between the antenna (517) and the secondary battery (513). The layer (519) has the function of shielding, for example, the electromagnetic field from the secondary battery (513). For example, a magnetic material can be used as the layer (519).

[0317] Various secondary batteries described above can be used as secondary batteries (513).

[0318] This embodiment can be appropriately combined with the description of other embodiments.

[0319] (Embodiment 2)

[0320] In this embodiment, an example of a secondary battery of one form of the present invention and a storage system equipped with a battery control circuit is described.

[0321] FIG. 16 (A) is a conceptual diagram of a storage system in which a battery control circuit (912) formed on a flexible substrate, which is a flexible film, is mounted on a secondary battery (913). The circuit board (900) is constructed using a flexible substrate. In addition, FIG. 16 (B), (C), and (D) are diagrams explaining the method of manufacturing the storage system shown in FIG. 16 (A).

[0322] Fig. 16 (B) shows a secondary battery (913). The secondary battery (913) has terminals (951) and (952). Fig. 16 (C) shows a circuit board (900) in an unfolded state.

[0323] As shown in (D) of FIG. 16, by bending the circuit board (900) and mounting it so as to be wrapped around the secondary battery (913), the energy storage system shown in (A) of FIG. 16 can be formed.

[0324] A capacitor system of one form of the present invention has a secondary battery (913) and a battery control circuit (912). Additionally, the battery control circuit (912) has a switch. The switch can be configured, for example, using a transistor.

[0325] In addition, a capacitor system of one form of the present invention preferably has a layer (916) and an antenna (914) formed on a circuit board (900). The layer (916) is, for example, an insulating sheet. The antenna (914) is electrically connected, for example, to a battery control circuit (912). The battery control circuit (912) has, for example, a circuit for transmitting and receiving signals from the antenna (914), such as a modulation circuit, a demodulation circuit, etc.

[0326] A first transmission path, which is connected to a terminal (951) of a secondary battery (913) and transmits power output from the secondary battery (913), is electrically connected to a terminal of a charging control circuit through an electrode (971). Additionally, a second transmission path, which is connected to a terminal (952) of the secondary battery (913), is connected to a switch that blocks the second transmission path through an electrode (972). The switch controls conduction and blocking operations and can also be described as a switching means that switches between supply and blocking.

[0327] As a manufacturing method for forming a battery control circuit (912) on a circuit board (900), a method is used in which the battery control circuit (912) is formed on a semiconductor substrate, then peeled off using a peeling method, and then fixed on the circuit board (900). Known techniques may be used for the peeling method. Alternatively, a method may be used in which the battery control circuit (912) is formed on a semiconductor substrate, then the back surface is polished, and then fixed on the circuit board (900). Alternatively, a method may be used in which the circuit board (900) is fixed after so-called laser cutting, which involves partially cutting using a laser beam. Alternatively, a method may be used in which the battery control circuit (912) is formed directly on the circuit board (900). Alternatively, a method may be used in which the battery control circuit (912) formed on a glass substrate is peeled off and then fixed on the circuit board (900).

[0328] When the battery control circuit (912) detects an abnormality such as a micro-short circuit, the second transmission path can be blocked by inputting a signal to the gate of a switch that blocks the second transmission path. When the second transmission path is blocked, the supply of current from the charger or the supply of current to an electronic device connected to the battery control circuit (912) can be stopped. In addition, by maintaining the signal voltage applied to the gate of the switch that blocks the second transmission path in a memory circuit (including a transistor using an oxide semiconductor), the blockage can be maintained for a long time. Therefore, it can be made into a storage system with high safety.

[0329] When charging the secondary battery (913) by supplying power from a charger, the secondary battery (913) becomes charged, and the battery control circuit (912) monitors the behavior of voltage or current at the electrode (971) and electrode (972), and if an abnormality is detected, the second transmission path is blocked to stop charging.

[0330] A charger refers to, for example, a device equipped with an adapter connected to an external power source, or a device that performs power transmission using wireless signals. Additionally, chargers may be built into electronic devices such as mobile devices.

[0331] This embodiment can be appropriately combined with the description of other embodiments.

[0332] (Embodiment 3)

[0333] In this embodiment, an example of mounting a secondary battery of one form of the present invention in a vehicle is described. Examples of vehicles include automobiles, motorcycles, bicycles, etc.

[0334] A secondary battery of one embodiment of the present invention has a high energy density. It also has a long lifespan and excellent reliability. Furthermore, it is desirable to use a secondary battery of one embodiment of the present invention in combination with a battery control circuit to extend the lifespan of the secondary battery. Additionally, by using a secondary battery of one embodiment of the present invention in combination with a battery control circuit, the safety of electronic devices, vehicles, etc., in which the secondary battery is installed can be enhanced.

[0335] In the following, an example is described of a storage system in which a secondary battery of one embodiment of the present invention and a battery control circuit are combined and mounted on a vehicle; however, in the configuration described below, the storage system mounted on the vehicle may be configured not to have the battery control circuit described above. For example, only the secondary battery of one embodiment of the present invention may be applied to the vehicle described below.

[0336] By equipping a vehicle with a battery storage system, next-generation clean energy vehicles such as hybrid vehicles (HV), electric vehicles (EV), or plug-in hybrid vehicles (PHV) can be realized.

[0337] In FIG. 17 (A), (B), and (C), a vehicle using a battery storage system, which is one embodiment of the present invention, is illustrated. The vehicle (8400) shown in FIG. 17 (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. By using one embodiment of the present invention, a vehicle with a long driving range can be realized. The vehicle (8400) has a battery storage system. The battery storage system not only drives the electric motor (8406) but can also supply power to light-emitting devices such as headlights (8401) or interior lights (not shown).

[0338] In addition, the energy storage system can supply power to display devices such as a speedometer and a tachometer that the vehicle (8400) has. In addition, the energy storage system can supply power to a navigation system that the vehicle (8400) has.

[0339] The vehicle (8500) shown in FIG. 17 (B) can be charged by receiving power from an external charging facility, such as through a plug-in method or a contactless power supply method, into the energy storage system (8024) of the vehicle (8500). FIG. 17 (B) shows a state in which charging is performed from a ground-mounted charging device (8021) to the energy storage system (8024) mounted on the vehicle (8500) via a cable (8022). When charging, it is appropriate to use a specific method such as CHAdeMO (registered trademark) or Combo as the charging method or connector specifications. The charging device (8021) may be a charging station provided at a commercial facility or may be a household power source. For example, the energy storage system (8024) mounted on the vehicle (8500) can be charged by supplying power from an external source using plug-in technology. Charging can be performed by converting alternating current power into direct current power through a conversion device such as an ACDC converter.

[0340] In addition, although not explicitly stated, a power receiving device can be mounted on the vehicle to charge it by supplying power non-contactually from a ground-based power transmission device. In this non-contact power supply method, charging is possible not only while stopped but also while driving by integrating power transmission devices with roads or exterior walls. Furthermore, this non-contact power supply method may be used to transmit and receive power between vehicles. Additionally, solar cells may be provided on the exterior of the vehicle to charge the energy storage system while stopped or driving. Electromagnetic induction or magnetic resonance methods can be utilized for such non-contact power supply.

[0341] Also, (C) of FIG. 17 shows an example of a two-wheeled vehicle using a battery storage system of one form of the present invention. The scooter (8600) shown in (C) of FIG. 17 has a battery storage system (8602), a side mirror (8601), and a turn signal (8603). The battery storage system (8602) can supply electricity to the turn signal (8603).

[0342] In addition, the scooter (8600) shown in (C) of FIG. 17 can store a battery storage system (8602) in a storage space (8604) under the seat. The battery storage system (8602) can be stored in the storage space (8604) under the seat even if the storage space (8604) under the seat is small.

[0343] In addition, FIG. 18 (A) shows an example of an electric bicycle using a battery storage system of one form of the present invention. A battery storage system of one form of the present invention can be applied to the electric bicycle (8700) shown in FIG. 18 (A).

[0344] The electric bicycle (8700) has a battery storage system (8702). The battery storage system (8702) can supply electricity to a motor that assists the driver. Additionally, the battery storage system (8702) can be carried and is shown in the state detached from the bicycle in Fig. 18 (B). Additionally, the battery storage system (8702) has a plurality of batteries (8701) built into it, which are of a battery storage system of one form of the present invention, and the remaining battery capacity, etc., can be displayed on a display unit (8703). Additionally, the battery storage system (8702) has a control circuit (8704) of one form of the present invention. The control circuit (8704) is electrically connected to the positive and negative terminals of the batteries (8701). As the control circuit (8704), the battery control circuit described in the previous embodiment can be used.

[0345] This embodiment can be appropriately combined with the description of other embodiments.

[0346] (Embodiment 4)

[0347] In this embodiment, an example of mounting a secondary battery of one form of the present invention in an electronic device is described.

[0348] A secondary battery of one embodiment of the present invention has a high energy density. It also has a long lifespan and excellent reliability. Furthermore, it is desirable to use a secondary battery of one embodiment of the present invention in combination with a battery control circuit to extend the lifespan of the secondary battery. Additionally, by using a secondary battery of one embodiment of the present invention in combination with a battery control circuit, the safety of electronic devices, vehicles, etc., in which the secondary battery is installed can be enhanced.

[0349] In the following, an example is described of a storage system incorporating a secondary battery of one embodiment of the present invention and a battery control circuit into an electronic device; however, in the configuration described below, the storage system mounted in the electronic device may be configured not to have the battery control circuit described above. For example, only the secondary battery of one embodiment of the present invention may be applied to the electronic device described below.

[0350] Figures 19 (A) and (B) illustrate an example of a tablet-type terminal (including a clamshell-type terminal) that can be folded in half. The tablet-type terminal (9600) shown in Figures 19 (A) and (B) comprises a housing (9630a), a housing (9630b), a movable part (9640) connecting the housing (9630a) and the housing (9630b), a display part (9631), a display mode switching switch (9626), a power switch (9627), a power saving mode switching switch (9625), a locking part (9629), and an operation switch (9628). By using a flexible panel in the display part (9631), the tablet-type terminal can be made to have a wider display area. Figure 19 (A) shows the tablet-type terminal (9600) in an unfolded state, and Figure 19 (B) shows the tablet-type terminal (9600) in a closed state.

[0351] Additionally, the tablet-type terminal (9600) has a shaft (9635) inside the housing (9630a) and the housing (9630b). The shaft (9635) is provided from the housing (9630a) through the movable part (9640) to the housing (9630b).

[0352] A portion of the display unit (9631) may be a touch panel area, and data can be entered by touching the displayed operation keys. Additionally, a keyboard button can be displayed on the display unit (9631) by touching the location on the touch panel where the keyboard display switching button is displayed with a finger or a stylus.

[0353] Additionally, the display mode switching switch (9626) can select the switching of the display direction, such as vertical display or horizontal display, or the switching of the black and white display or color display. The power saving mode switching switch (9625) can optimize the brightness of the display according to the amount of external light detected during use by a light sensor built into the tablet terminal (9600). The tablet terminal may be equipped with other detection devices, such as a gyroscope, an accelerometer, or a tilt-detecting sensor, in addition to the light sensor.

[0354] Figure 19 (B) shows a closed state of a tablet-type terminal, and the tablet-type terminal has a housing (9630), a solar cell (9633), and a storage system of one form of the present invention. The storage system has a control circuit (9634) and a battery (9635). As the control circuit (9634), the battery control circuit described in the previous embodiment may be used.

[0355] Additionally, since the tablet-type terminal (9600) can be folded in half, when not in use, the housing (9630a) and the housing (9630b) can be folded so that they overlap each other. Since the display part (9631) can be protected when folded, the durability of the tablet-type terminal (9600) can be increased.

[0356] In addition to this, the tablet-type terminal shown in (A) and (B) of FIG. 19 may have a function for displaying various information (still images, videos, text images, etc.), a function for displaying a calendar, date, or time on the display unit, a touch input function for operating or editing the information displayed on the display unit by touch input, and a function for controlling processing by various software (programs).

[0357] Power can be supplied to a touch panel, display unit, or image signal processing unit, etc. by means of a solar cell (9633) mounted on the surface of a tablet-type terminal. Additionally, the solar cell (9633) can be provided on one or both sides of the housing (9630) and configured to efficiently perform charging of the capacitor (9635).

[0358] In addition, with reference to FIG. 19 (A) and (B), a configuration in which a control circuit using the battery control circuit described in the previous embodiment is applied to a tablet-type terminal that can be folded in half has been described, but other configurations may also be used. For example, as shown in FIG. 19 (C), it may be applied to a laptop-type personal computer which is a clamshell-type terminal. FIG. 19 (C) shows a laptop-type personal computer (9601) having a display unit (9631) in the housing (9630a) and a keyboard unit (9650) in the housing (9630b). The laptop-type personal computer (9601) has a control circuit (9634) and a capacitor (9635) as described with reference to FIG. 19 (A) and (B). As for the control circuit (9634), the battery control circuit described in the previous embodiment may be used.

[0359] An example of another electronic device is shown in FIG. 20. In FIG. 20, a display device (8000) is an example of an electronic device in which a storage system of one form of the present invention is installed. Specifically, the display device (8000) corresponds to a display device for receiving TV broadcasts and has a housing (8001), a display unit (8002), a speaker unit (8003), a secondary battery (8004), etc. A detection system according to one form of the present invention is provided inside the housing (8001). The display device (8000) may receive power from a commercial power source or may use power stored in the secondary battery (8004).

[0360] In the display unit (8002), a semiconductor display device such as a liquid crystal display device, a light-emitting device equipped with a light-emitting element such as an organic EL element in each pixel, an electrophoretic display device, a DMD (Digital Micromirror Device), a PDP (Plasma Display Panel), or a FED (Field Emission Display) may be used.

[0361] In addition, the voice input device (8005) also uses a secondary battery. The voice input device (8005) has a storage system as described in the previous embodiment. The voice input device (8005) has a plurality of sensors (optical sensor, temperature sensor, humidity sensor, barometric pressure sensor, illuminance sensor, motion sensor, etc.) including a microphone in addition to a wireless communication element, and can operate other devices by the user’s command words, and can perform, for example, power operation of a display device (8000) and light intensity control of a lighting device (8100). The voice input device (8005) can operate peripheral devices by voice and can replace a manual remote controller.

[0362] Additionally, the voice input device (8005) has wheels or mechanical means of movement and moves in the direction from which the sound of the user speaking is heard, and has a configuration that accurately understands the command through a built-in microphone and displays the content on the display unit (8008), or allows touch input operation to be performed on the display unit (8008).

[0363] Additionally, the voice input device (8005) can also function as a charging dock for a portable information terminal (8009), such as a smartphone. Power can be transmitted and received between the portable information terminal (8009) and the voice input device (8005) via wired or wireless means. Since the portable information terminal (8009) does not need to be carried around indoors, it is desirable to manage and maintain the secondary battery through the voice input device (8005) in order to avoid degradation caused by a load being applied to the secondary battery while maintaining the necessary capacity. Furthermore, since the voice input device (8005) has a speaker (8007) and a microphone, hands-free conversation is possible even while the portable information terminal (8009) is charging. Additionally, when the capacity of the secondary battery decreases, the voice input device (8005) moves in the direction indicated by the arrow and is preferably charged by wireless charging from a charging module (8010) connected to an external power source.

[0364] Additionally, the voice input device (8005) may be placed on a stand. Alternatively, wheels or mechanical means of movement may be provided to move the voice input device (8005) to a desired location, or the voice input device (8005) may be fixed to a desired location, for example, on the floor, without providing a stand or wheels.

[0365] In addition, display devices include all information display devices, such as those for personal computers and advertising displays, in addition to those for receiving TV broadcasts.

[0366] In FIG. 20, the installed lighting device (8100) is an example of an electronic device using a secondary battery (8103) controlled by a microprocessor (including an APS) that controls charging. Specifically, the lighting device (8100) has a housing (8101), a light source (8102), a secondary battery (8103), etc. FIG. 20 illustrates a case where the secondary battery (8103) is provided inside a ceiling (8104) in which the housing (8101) and the light source (8102) are installed, but the secondary battery (8103) may be provided inside the housing (8101). The lighting device (8100) may receive power from a commercial power source or may use power stored in the secondary battery (8103).

[0367] In addition, while FIG. 20 illustrates a fixed lighting device (8100) provided on the ceiling (8104), the secondary battery (8103) may be used in a fixed lighting device provided on a side wall (8105), floor (8106), window (8107), etc., in addition to the ceiling (8104), and may also be used in a tabletop lighting device, etc.

[0368] In addition, as a light source (8102), an artificial light source that obtains light artificially using electric power can be used. Specifically, discharge lamps such as incandescent bulbs and fluorescent lamps, and light-emitting elements such as LEDs and organic EL elements can be cited as examples of the artificial light source.

[0369] An air conditioner having an indoor unit (8200) and an outdoor unit (8204) in FIG. 20 is an example of an electronic device using a secondary battery (8203). Specifically, the indoor unit (8200) has a housing (8201), an air outlet (8202), a secondary battery (8203), etc. FIG. 20 illustrates a case where the secondary battery (8203) is provided to the indoor unit (8200), but the secondary battery (8203) may be provided to the outdoor unit (8204). Alternatively, the secondary battery (8203) may be provided to both the indoor unit (8200) and the outdoor unit (8204). The air conditioner may receive power from a commercial power source or may use power stored in the secondary battery (8203).

[0370] In FIG. 20, the electric freezer refrigerator (8300) is an example of an electronic device using a secondary battery (8304). Specifically, the electric freezer refrigerator (8300) has a housing (8301), a refrigerator door (8302), a freezer door (8303), a secondary battery (8304), etc. In FIG. 20, the secondary battery (8304) is provided inside the housing (8301). The electric freezer refrigerator (8300) may receive power from a commercial power source or may use power stored in the secondary battery (8304).

[0371] In addition, by storing power in a secondary battery during periods when electronic devices are not used, particularly during periods when the ratio of the amount of power actually used to the total amount of power that can be supplied by the commercial power source (referred to as the power usage rate) is low, it is possible to suppress the increase in the power usage rate outside of the aforementioned periods. For example, in the case of an electric refrigerator (8300), power is stored in the secondary battery (8304) at night when the temperature is low and the refrigerator door (8302) and freezer door (8303) are not opened or closed. Then, by using the secondary battery (8304) as an auxiliary power source during the day when the temperature is high and the refrigerator door (8302) and freezer door (8303) are opened or closed, the power usage rate during the day can be suppressed to a low level.

[0372] In addition to the electronic devices described above, secondary batteries can be installed in various electronic devices. According to one embodiment of the present invention, the cycle characteristics of the secondary battery are improved. Therefore, by installing a microprocessor (including an APS) that controls charging, which is one embodiment of the present invention, in the electronic device described in this embodiment, the electronic device can be made to have a longer lifespan. This embodiment can be implemented in appropriate combination with other embodiments.

[0373] Examples of a capacitor system of one form of the present invention mounted on an electronic device are shown in FIG. 21 (A) to (G). Electronic devices to which a capacitor system of one form of the present invention is applied include, for example, a television device (also called a television or television receiver), a monitor for a computer, a digital camera, a digital video camera, a digital photo frame, a mobile phone (also called a mobile phone or mobile phone device), a portable game console, a portable information terminal, an audio playback device, a large game console such as a pachinko machine, etc.

[0374] Figure 21 (A) shows an example of a mobile phone. In addition to a display unit (7402) provided in a housing (7401), the mobile phone (7400) has an operation button (7403), an external connection port (7404), a speaker (7405), a microphone (7406), etc. Furthermore, the mobile phone (7400) has a storage system of one form of the present invention. The storage system of one form of the present invention has, for example, a battery (7407) and a battery control circuit as described in the preceding embodiment.

[0375] Figure 21 (B) shows a bent state of a mobile phone (7400). When the mobile phone (7400) is deformed by an external force to bend the entire device, the battery (7407) provided inside may also be bent. In such cases, it is preferable to use a flexible battery as the battery (7407). Figure 21 (C) shows a bent state of a flexible battery. A control circuit (7408) is electrically connected to the battery. As the control circuit (7408), the battery control circuit described in the previous embodiment may be used.

[0376] In addition, a battery having a flexible shape can be provided along the curved surfaces of the interior or exterior walls of houses or buildings, or the interior or exterior of automobiles.

[0377] Figure 21 (D) shows an example of a bangle-type display device. The portable display device (7100) has a housing (7101), a display unit (7102), an operation button (7103), and a battery storage system of one form of the present invention. The battery storage system of one form of the present invention has, for example, a battery (7104) and a battery control circuit as described in the preceding embodiment.

[0378] Figure 21 (E) shows an example of a wristwatch-type portable information terminal. The portable information terminal (7200) has a housing (7201), a display unit (7202), a band (7203), a buckle (7204), an operation button (7205), an input / output terminal (7206), etc.

[0379] The portable information terminal (7200) can run various applications such as mobile phone, email, reading and writing text, music playback, internet communication, and computer games.

[0380] The display unit (7202) is provided with a curved display surface and can display along the curved display surface. Additionally, the display unit (7202) has a touch sensor and can be operated by touching the screen with a finger or a stylus. For example, an application can be launched by touching an icon (7207) displayed on the display unit (7202).

[0381] In addition to setting the time, the operation button (7205) may have various functions such as turning the power on / off, turning wireless communication on / off, enabling and disabling silent mode, and enabling and disabling power saving mode. For example, the functions of the operation button (7205) may be freely set by an operating system combined with the portable information terminal (7200).

[0382] In addition, the portable information terminal (7200) can perform short-range wireless communication according to the communication standard. For example, it can make hands-free calls by communicating with a headset capable of wireless communication.

[0383] Additionally, the portable information terminal (7200) has an input / output terminal (7206) and can directly transmit and receive data with another information terminal through a connector. It can also be charged through the input / output terminal (7206). Additionally, the charging operation may be performed by wireless power supply without using the input / output terminal (7206).

[0384] A portable information terminal (7200) has a storage system of one form of the present invention. The storage system has a battery and a battery control circuit as described in the preceding embodiment.

[0385] It is preferable for the portable information terminal (7200) to have a sensor. As a sensor, it is preferable to equip it with a human body sensor such as a fingerprint sensor, a pulse sensor, or a body temperature sensor, or a touch sensor, a pressure sensor, or an accelerometer.

[0386] (F) of FIG. 21 shows an example of an armband-type display device. The display device (7300) has a display unit (7304) and a secondary battery of one form of the present invention. In addition, the display device (7300) may have a touch sensor on the display unit (7304) and may also function as a portable information terminal.

[0387] The display unit (7304) has a curved display surface and can display along the curved display surface. Additionally, the display device (7300) can change the display status through short-range wireless communication according to communication standards, etc.

[0388] Additionally, the display device (7300) has an input / output terminal and can directly transmit and receive data with another information terminal through a connector. It can also be charged through the input / output terminal. Additionally, the charging operation may be performed by wireless power supply without using the input / output terminal.

[0389] By using a secondary battery of one form of the present invention as a secondary battery for household electronic devices, it is possible to provide a lightweight product with a long lifespan. For example, household electronic devices include electric toothbrushes, electric shavers, and electric beauty devices, and for the secondary batteries of these products, there is a demand for secondary batteries that are small, lightweight, and have a large capacity, with a stick-like shape that is easy for the user to hold.

[0390] FIG. 21 (G) is a perspective view of a device also called a tobacco smoking device (electronic cigarette). In FIG. 21 (G), the electronic cigarette (7500) is composed of a nebulizer (7501) including a heating element, a secondary battery (7504) that supplies power to the nebulizer, and a cartridge (7502) including a liquid supply bottle or a sensor. To increase safety, a protection circuit that prevents overcharging or over-discharging of the secondary battery (7504) may be electrically connected to the secondary battery (7504). The secondary battery (7504) shown in FIG. 21 (G) has an external terminal so that it can be connected to a charging device. Since the secondary battery (7504) becomes the tip when held, it is desirable that the total length be short and the weight be light. Since the secondary battery of one embodiment of the present invention has high capacity and good cycle characteristics, it can provide a small and lightweight electronic cigarette (7500) that can be used for a long time over a long period.

[0391] Next, an example of an electronic device having a battery control circuit of one form of the present invention will be described using FIG. 22.

[0392] The robot (7000) has a secondary battery, an illuminance sensor, a microphone, a camera, a speaker, a display, various sensors (infrared sensor, ultrasonic sensor, accelerometer, piezo sensor, light sensor, gyroscope sensor, etc.), and a moving mechanism. By applying a battery storage system equipped with a battery control circuit of one form of the present invention to the secondary battery of the robot (7000), control and protection of the secondary battery can be performed.

[0393] The microphone has the function of detecting acoustic signals such as the user's voice and environmental sounds. Additionally, the speaker has the function of outputting audio signals such as voice and warning sounds. The robot (7000) can interpret audio signals input through the microphone and output necessary audio signals from the speaker. The robot (7000) can communicate with the user using the microphone and the speaker.

[0394] The camera has the function of capturing images of the surroundings of the robot (7000). In addition, the robot (7000) has the function of moving using a moving mechanism. The robot (7000) can capture images of the surroundings using the camera and analyze the images to detect the presence or absence of obstacles when moving.

[0395] The aircraft (7120) has a propeller, a camera, and a secondary battery, and has the ability to fly autonomously.

[0396] In addition, by applying a battery control circuit of one form of the present invention to the secondary battery of the aircraft (7120), a storage system can be performed to control and protect the secondary battery in addition to reducing weight.

[0397] The robot vacuum cleaner (7140) has a secondary battery, a display placed on the top surface, a plurality of cameras placed on the side, a brush, an operation button, various sensors, etc. Although not illustrated, the robot vacuum cleaner (7140) is provided with wheels, a suction port, etc. The robot vacuum cleaner (7140) can drive autonomously, detect dust, and suck up dust from a suction port provided on the bottom surface. By applying a storage system equipped with a battery control circuit of one form of the present invention that is electrically connected to the secondary battery of the robot vacuum cleaner (7140), the number of parts used can be reduced, and abnormalities such as micro-short circuits of the secondary battery can also be detected.

[0398] An electric vehicle (7160) is shown as an example of a mobile body. The electric vehicle (7160) has a secondary battery, wheels, brakes, a steering device, a camera, etc. By applying a storage system equipped with a battery control circuit of one form of the present invention connected to the secondary battery of the electric vehicle (7160), the number of parts used can be reduced, and abnormalities such as micro-short circuits in the secondary battery can also be detected.

[0399] Furthermore, although electric vehicles were described above as an example of a mobile body, mobile bodies are not limited to electric vehicles. For example, mobile bodies include subways, monorails, ships, and aircraft (helicopters, unmanned aerial vehicles (drones), airplanes, rockets), and by applying a storage system equipped with a battery control circuit of one form of the present invention that is electrically connected to the secondary battery of these mobile bodies, the number of components used can be reduced, and abnormalities such as micro-short circuits in the secondary battery can also be detected.

[0400] A secondary battery having a battery control circuit of one form of the present invention can be provided in a smartphone (7210), a PC (7220) (personal computer), a game console (7240), etc.

[0401] A smartphone (7210) is an example of a portable information terminal. The smartphone (7210) has a microphone, a camera, a speaker, various sensors, and a display unit. These peripheral devices are controlled by a charging control circuit. By applying a storage system equipped with a battery control circuit of the present invention that is electrically connected to the secondary battery of the smartphone (7210), the number of parts used can be reduced, and the control and protection of the secondary battery can be performed, thereby increasing safety.

[0402] PC (7220) is an example of a notebook PC. By applying a storage system equipped with a battery control circuit of one form of the present invention that is electrically connected to a secondary battery of the notebook PC, the number of components used can be reduced, and the control and protection of the secondary battery can be performed, thereby increasing safety.

[0403] The game console (7240) is an example of a portable game console. The game console (7260) is an example of a home console. A controller (7262) is connected to the game console (7260) wirelessly or via a wire. By applying a battery storage system equipped with a battery control circuit of one form of the present invention to the controller (7262), the number of parts used can be reduced, and the control and protection of the secondary battery can be performed, thereby increasing safety.

[0404] Figure 23 (A) shows an example of a wearable device. The wearable device uses a secondary battery as a power source. In addition, since the wearable device is used by the user in daily life or outdoors, it is required to have high water resistance and be capable of wireless charging as well as wired charging with the connector part exposed.

[0405] For example, it can be mounted on a glasses-type device (490) as shown in (A) of FIG. 23. The glasses-type device (490) has a frame (490a) and a display part (490b). By mounting a secondary battery on the temple part of the curved frame (490a), it can be made into a glasses-type device (490) that is lightweight, has good weight balance, and has a long continuous usage time.

[0406] Additionally, it can be mounted on a headset-type device (491). The headset-type device (491) has at least a microphone part (491a), a flexible pipe (491b), and an earphone part (491c). A secondary battery can be provided within the flexible pipe (491b) or within the earphone part (491c).

[0407] In addition, it can be mounted on a device (402) that can be directly attached to the body. A secondary battery (402b) can be provided within the thin housing (402a) of the device (402).

[0408] In addition, it can be mounted on a device (403) that can be attached to clothing. A secondary battery (403b) can be provided within the thin housing (403a) of the device (403).

[0409] It can also be mounted on a belt-type device (406). The belt-type device (406) has a belt section (406a) and a wireless power supply / receiving section (406b), and a secondary battery can be mounted inside the belt section (406a).

[0410] Additionally, it can be mounted on a wristwatch-type device (405). The wristwatch-type device (405) has a display unit (405a) and a belt unit (405b), and a secondary battery can be provided to the display unit (405a) or the belt unit (405b).

[0411] The display unit (405a) can display not only the time but also various information such as incoming mail or phone calls.

[0412] In addition, since the wristwatch-type device (405) is a wearable device that is worn directly on the arm, it may be equipped with a sensor that measures the user's pulse, blood pressure, etc. Data regarding the user's exercise amount and health can be accumulated and used to maintain health.

[0413] The wristwatch-type device (405) shown in (A) of FIG. 23 will be described in detail below.

[0414] Figure 23 (B) is a perspective view of a wristwatch-type device (405) removed from the wrist.

[0415] Also, (C) of FIG. 23 is a side view. FIG. 23 (C) shows a state in which a secondary battery (913) is included inside. The secondary battery (913) is provided in a position overlapping with the display part (405a) and is small and light.

[0416] Additionally, it is preferable that the wristwatch-type device (405) has a battery control circuit internally that is electrically connected to a secondary battery (913).

[0417] This embodiment can be appropriately combined with the description of other embodiments.

[0418] (Notes on the description in this specification, etc.)

[0419] The above embodiments and the descriptions of each component in the embodiments are appended below.

[0420] The configurations described in each embodiment can be appropriately combined with the configurations described in other embodiments to form one form of the present invention. In addition, when multiple configuration examples are described in one embodiment, the configuration examples can be appropriately combined.

[0421] In addition, the contents described in any one embodiment (may be partial contents) may be applied, combined, or substituted with other contents described in that embodiment (may be partial contents) and / or contents described in one or more other embodiments (may be partial contents).

[0422] In addition, the content described in the embodiments refers to the content described using various drawings in each embodiment, or the content described using sentences written in the specification.

[0423] In addition, a drawing (which may be part of) presented in any one embodiment may be combined with other parts of that drawing, other drawings (which may be part of) presented in that embodiment, and / or drawings (which may be part of) presented in one or more other embodiments to form more drawings.

[0424] Furthermore, in this specification and others, components in the block diagrams are classified by function and represented as independent blocks. However, in actual circuits, it is difficult to classify components by function, and there may be cases where multiple functions are involved in a single circuit, or where a single function is involved in multiple circuits. Therefore, the blocks in the block diagrams are not limited to the components described in the specification and may be appropriately changed depending on the situation.

[0425] In addition, in the drawings, the size, layer thickness, or area is shown in arbitrary sizes for convenience of explanation. Therefore, it is not necessarily limited to that scale. Furthermore, the drawings are depicted schematically for clarity and are not limited to the shapes or values ​​shown in the drawings. For example, it may include deviations in signal, voltage, or current caused by noise, or deviations in signal, voltage, or current caused by timing misalignment.

[0426] When describing the connection relationship of a transistor in the present specification, etc., notations such as "one of the source and drain (or the first electrode or the first terminal)" and "the other of the source and drain (or the second electrode or the second terminal)" are used. This is because the source and drain of the transistor change depending on the structure or operating conditions of the transistor. In addition, the terms source and drain of the transistor may be appropriately changed depending on the situation, such as source (drain) terminal or source (drain) electrode.

[0427] Furthermore, the terms "electrode" or "wiring" in this specification and others do not functionally limit these components. For example, an "electrode" may be used as part of a "wiring," and vice versa. Additionally, the terms "electrode" or "wiring" include cases where multiple "electrodes" or "wiring" are formed as a single unit.

[0428] In addition, voltage and potential may be appropriately interchanged in this specification and the like. Voltage refers to the potential difference from a reference potential, and for example, if the reference potential is ground voltage, voltage may be interchanged with potential. Ground potential does not necessarily mean 0V. Also, potential is relative, and depending on the reference potential, the potential applied to wiring, etc. may change.

[0429] In addition, expressions such as "film" and "layer" in this specification, etc., may be interchanged depending on the case or situation. For example, the term "conductive layer" may be changed to the term "conductive film." Or, for example, the term "insulating film" may be changed to the term "insulating layer."

[0430] In the present specification, etc., the term "switch" refers to a device having the function of controlling whether to conduct current by becoming in a conducting state (on state) or a non-conducting state (off state). Alternatively, the term "switch" refers to a device having the function of selecting and switching the path through which current flows.

[0431] In the present specification and others, channel length refers to, for example, the distance between the source and the drain in the region where the semiconductor (or the part within the semiconductor through which current flows when the transistor is in the ON state) and the gate overlap in the top view of the transistor, or in the region where the channel is formed.

[0432] In the present specification, etc., channel width refers to, for example, the length of the region where the semiconductor (or the part where current flows within the semiconductor when the transistor is in the ON state) and the gate electrode overlap, or the length of the region where the source and drain face each other in the region where the channel is formed.

[0433] In this specification and others, the phrase "A and B are connected" includes cases where A and B are electrically connected, in addition to cases where A and B are directly connected. Here, "A and B are electrically connected" refers to a case where the transmission and reception of electrical signals is possible between A and B when an object having some electrical action exists between A and B.

[0434] (Example 1)

[0435] In this embodiment, a method for manufacturing a secondary battery of one form of the present invention and the characteristics of the manufactured secondary battery are described.

[0436] [Formation of positive active material]

[0437] A positive active material was formed.

[0438] First, a first mixture containing magnesium and fluorine was formed. LiF and MgF2 were weighed so that the molar ratio was LiF:MgF2 = 1:3, and acetone was added as a solvent to wet-mix and grind the mixture. Mixing and grinding were performed using a ball mill with zirconia balls at 400 rpm for 12 hours. The material after treatment was recovered and used as the first mixture.

[0439] Next, lithium cobaltate was prepared as a composite oxide containing lithium and cobalt. More specifically, CELLSEED C-10N manufactured by NIPPON CHEMICAL INDUSTRIAL CO., LTD. was prepared.

[0440] Next, regarding the molecular weight of lithium cobaltate, magnesium was weighed so that its atomic weight in the first mixture was 0.5 atomic%, and the mixture was mixed dry. Mixing was performed using a ball mill with zirconia balls at 150 rpm for 1 hour. The material after treatment was recovered to obtain the second mixture.

[0441] Next, the second mixture was placed in an alumina crucible and annealed at 850°C for 60 hours in a muffle furnace under an oxygen atmosphere. The lid of the alumina crucible was covered during annealing. The oxygen flow rate was set to 10 L / min. The temperature was raised at 200°C / hr, and the temperature was lowered over a period of more than 10 hours. The material after heat treatment was used as the positive electrode active material.

[0442] [Production of the bipolar]

[0443] Next, a positive electrode was fabricated using the positive electrode active material formed above. The positive electrode active material formed above, acetylene black (AB), and polyvinylidene fluoride (PVDF) were mixed in a ratio of positive electrode active material:AB:PVDF = 95:3:2 (weight ratio), and a slurry was formed using NMP as the solvent. The formed slurry was coated onto a current collector, and the solvent was evaporated. Subsequently, a press of 179 kN / m was performed at 120°C, followed by a press of 1249 kN / m, to form a positive electrode active material layer on the current collector, thereby fabricating a positive electrode (P1). In the positive electrode (P1), the amount of positive electrode active material loaded was varied according to the battery cell used. An aluminum foil with a thickness of 20 μm was used as the current collector. The positive electrode active material layer was provided on one side of the current collector.

[0444] [Fabrication of the Cathode]

[0445] A cathode was fabricated using graphite as the cathode active material.

[0446] Cathodes were fabricated using two types of graphite. For the first type, the specific surface area was 6.3 m² 2 Spherical natural graphite with a g / g and an average particle size of 15 μm was used, mixed with CMC-Na and SBR in a weight ratio of graphite:CMC-Na:SBR = 97:1.5:1.5, and a slurry was formed using water as a solvent. As for the second type, a specific surface area of ​​1.5 m² 2 MCMB graphite with a weight of 1 / g was used, mixed with a conductive agent, CMC-Na, and SBR in a ratio of graphite:conductive agent:CMC-Na:SBR = 96:1:1:2 (weight ratio), and a slurry was formed using water as a solvent.

[0447] The degree of polymerization of the CMC-Na used was 600 to 800, and when used as a 1 weight% aqueous solution, the viscosity of the aqueous solution ranged from 300 mPa·s to 500 mPa·s. In addition, as a conductive aid, vapor-phase grown carbon fiber VGCF (registered trademark)-H (manufactured by SHOWA DENKO KK, fiber diameter 150 nm, specific surface area 13 m²) was used. 2 / g) was used.

[0448] Each formed slurry was coated onto a current collector, dried, and a negative active material layer was formed on the current collector. A copper foil with a thickness of 18 μm was used as the current collector. The negative active material layer was provided on both sides of the current collector.

[0449] A cathode using a first type of graphite is designated as the cathode (N1), and a cathode using a second type of graphite is designated as the cathode (N2). In the cathode (N1) and the cathode (N2), the amount of cathode active material loaded is varied according to the battery cell used.

[0450] [Production of secondary batteries]

[0451] Using the anode and cathode fabricated above, a secondary battery was manufactured using a film as the outer casing.

[0452] Cellulose with a thickness of 50 μm was used as a separator.

[0453] The layers were stacked in the order of positive electrode, separator, negative electrode, separator, and positive electrode. Two positive electrodes were each arranged so that the positive active material provided on one side of the current collector faced the negative active material with the separator in between.

[0454] Leads were attached to the positive and negative electrodes, respectively.

[0455] A laminate having a positive electrode, a negative electrode, and a separator was placed between the outer casings folded in half such that one end of the lead protruded to the outside of the outer casing. Next, one side of the outer casing was left as an open portion, and the other side was sealed.

[0456] As the film serving as the exterior body, a film was used in which a polypropylene layer, an acid-modified polypropylene layer, an aluminum layer, and a nylon layer were laminated in that order. The thickness of the film was approximately 110 μm. The film serving as the exterior body was folded so that the nylon layer was placed on the outer side and the polypropylene layer was placed on the inner side. The thickness of the aluminum layer was approximately 40 μm, the thickness of the nylon layer was approximately 25 μm, and the total thickness of the polypropylene layer and the acid-modified polypropylene layer was approximately 45 μm.

[0457] Next, under an argon gas atmosphere, the electrolyte was injected from one side left as an open section.

[0458] A total of five types of electrolytes (electrolytes (Sol_1, Sol_2, Sol_3, Sol_4, and Sol_5)) were formed as electrolytes, and any of the above electrolytes were used in each secondary battery.

[0459] Electrolytes (Sol_1) and (Sol_2) are described. EMI-FSA represented by structural formula (G11) was used as the solvent. In electrolyte (Sol_1), LiFSA (lithium bis(fluorosulfonyl)amide) was used as the electrolyte, and the concentration of the electrolyte in the electrolyte was set to 2.15 mol / L. In electrolyte (Sol_2), LiTFSA (lithium bis(trifluoromethanesulfonyl)amide) was used as the electrolyte, and the concentration of the electrolyte in the electrolyte was set to 1.50 mol / L.

[0460] [Chemical Formula 30]

[0461]

[0462] The electrolyte (Sol_3) is described. BMI-FSA, represented by structural formula (G12), was used as the solvent. LiFSA (lithium bis(fluorosulfonyl)amide) was used as the electrolyte. The concentration of the electrolyte in the electrolyte was set to 1.93 mol / L.

[0463] [Chemical Formula 31]

[0464]

[0465] The electrolyte (Sol_4) is described. P13-FSA, represented by structural formula (G13), was used as the solvent. LiFSA (lithium bis(fluorosulfonyl)amide) was used as the electrolyte. The concentration of the electrolyte in the electrolyte was set to 1.80 mol / L.

[0466] [Chemical Formula 32]

[0467]

[0468] The electrolyte (Sol_5) is described. As a solvent, a mixture of ethylene carbonate (EC) and diethyl carbonate (DEC) in a volume ratio of EC:DEC = 3:7 was used. Lithium hexafluoride phosphate (LiPF6) was used as the electrolyte. The concentration of the electrolyte in the solution was set to 1.00 mol / L.

[0469] The solvent and electrolyte used for each electrolyte are shown in Table 1.

[0470] [Table 1]

[0471]

[0472] Next, under a reduced pressure atmosphere, one side of the outer body left as an opening was sealed.

[0473] A secondary battery was manufactured through the above process.

[0474] [Aging]

[0475] Next, the secondary battery was aged.

[0476] First, the secondary battery was placed on two plates, and CC charging (0.01C, capacity 15mAh / g) was performed. Afterward, the two plates were separated, and under an argon atmosphere, one side of the outer casing was cut to open it, the gas was removed, and it was resealed. Here, CC represents constant current. The capacity of the secondary battery was calculated per unit weight of the positive active material. Additionally, the C-rate was calculated based on 1C according to the charge-discharge cycle conditions. In the evaluation of cycle characteristics, the values ​​were calculated as 190mA / g at a charging voltage of 4.4V, 210mAh / g at 4.45V, and 220mAh / g at 4.5V.

[0477] Next, the secondary battery was placed on two plates and CC charging (0.1C, capacity 120mAh / g) was performed. After that, the two plates were separated and maintained at 0°C for 24 hours, then one side of the outer casing was cut open under an argon atmosphere, the gas was released, and it was sealed again.

[0478] [Evaluation of Charge / Discharge Characteristics]

[0479] Next, the secondary battery was placed on two plates, and CCCV charging (0.1C, termination current 0.01C) and CC discharging (0.2C, 2.5V) were performed. The charging voltage was matched to the charging voltage used in the evaluation of cycle characteristics. Here, CV represents the constant voltage.

[0480] After that, CCCV charging (0.2C, termination current 0.01C) and CC discharging (0.2C, 2.5V) were repeated three times. The charging voltage was matched to the charging voltage used in the evaluation of cycle characteristics.

[0481] [Evaluation of Cycle Characteristics 1]

[0482] Next, the cycle characteristics of the secondary battery were evaluated at 25℃.

[0483] As battery cells, the cells shown in Table 2 (Cel_1 to Cel_7) were fabricated. The combinations of positive electrode, negative electrode, and electrolyte solution used, and the charge voltage are shown in Table 2.

[0484] [Table 2]

[0485]

[0486] In the C-rate or the capacity ratio described below, when the charging voltage is 4.4V, the capacity of the anode was set to 190mAh / g. When the charging voltage is 4.45V, the capacity of the anode was set to 210mAh / g. When the charging voltage is 4.5V, the capacity of the anode was set to 220mAh / g.

[0487] The loading amount of the positive active material on the positive electrode (P1) is approximately 6.5 mg / cm² in the cells (Cel_1 to Cel_4). 2 Set to, and at approximately 11 mg / cm² in cells (Cel_5 to Cel_7). 2 ...did so.

[0488] The area of ​​the positive active material layer of the positive electrode (P1) is 8.194 cm² 2 ...did so.

[0489] The loading amount of the negative active material of the negative electrode (N1) and negative electrode (N2) in each battery cell was adjusted so that the capacity ratio was approximately 77% or more and 83% or less. Here, the capacity ratio is a value representing the capacity of the positive electrode as a percentage of the capacity of the negative electrode. In calculating the capacity ratio, the capacity of the negative electrode was set to 330 mAh / g based on the weight of the negative active material. In addition, the loading amount of the negative active material was calculated by dividing the sum of the loading amounts in the negative active material layers provided on both sides of the current collector by half.

[0490] CCCV charging (0.2C, termination current 0.02C) was performed, and CC discharging (0.2C, 2.5V) was performed. The capacity of the secondary battery was calculated based on the weight of the positive active material.

[0491] The evaluation results of the cycle characteristics at 25℃ are shown in Figures 24 (A), (B), and 25.

[0492] Figure 24 (A) shows the results of the cycle characteristics of the cells (Cel_1 to Cel_4), where the horizontal axis represents the number of cycles and the vertical axis represents the discharge capacity. Figure 24 (B) shows an enlarged view of the vertical axis of Figure 24 (A).

[0493] Figure 25 shows the results of the cycle characteristics of the cells (Cel_5 to Cel_7).

[0494] In addition, the charge-discharge curves of the cells (Cel_1 to Cel_4) are shown in FIG. 26 (A) and (B), and FIG. 27 (A) and (B), respectively. The solid line represents the curve of the first cycle, and the dotted line represents the curve of the 100th cycle. In each charge-discharge curve, the vertical axis represents the voltage of charging or discharging, and the horizontal axis represents the capacity.

[0495] According to FIGS. 26 (A) and (B) and FIGS. 27 (A) and (B), even when the charging voltage was set to a very high value of 4.5V, a good charge-discharge curve was obtained in the first cycle for all cells (Cel_1 to Cel_4). This suggests that the positive active material of one embodiment of the present invention has high stability of the crystal structure even at high charging voltages.

[0496] In addition, looking at (A) and (B) of FIG. 24, it can be seen that the cells (Cel_1, Cel_2, and Cel_3) containing ionic liquid in the electrolyte maintain a capacity value of more than 80% of the first discharge capacity after the 300th cycle and exhibit excellent characteristics.

[0497] In addition, as shown in Fig. 25, it can be seen that excellent cycle characteristics are obtained even when the charging voltage is increased to 4.5V in a cell in which the loading amounts of the positive and negative active materials are increased and the type of graphite is changed.

[0498] As described above, it was found that in one embodiment of the secondary battery of the present invention, significantly superior characteristics are obtained by using an excellent positive active material and using an ionic liquid as the electrolyte.

[0499] [Evaluation of Cycle Characteristics 2]

[0500] Next, the cycle characteristics of the secondary battery were evaluated at 45℃.

[0501] As battery cells, the cells shown in Table 3 (Cel_11 to Cel_23) were fabricated. The combinations of positive electrode, negative electrode, and electrolyte solution used, and the charge voltage are shown in Table 3.

[0502] [Table 3]

[0503]

[0504] The loading amount of the positive active material of the positive electrode (P1) is approximately 6.5 mg / cm² in the cells (Cel_11 to Cel_20). 2 Set to, and at approximately 11 mg / cm² in cells (Cel_21 to Cel_23). 2 ...did so.

[0505] The area of ​​the positive active material layer of the positive electrode (P1) is 8.194 cm² 2 ...did so.

[0506] The loading amount of the negative active material of the negative electrode (N1) and negative electrode (N2) in each battery cell was adjusted so that the capacity ratio was approximately 77% or more and 83% or less.

[0507] CCCV charging (0.2C, termination current 0.02C) was performed, and CC discharging (0.2C, 2.5V) was performed. The capacity of the secondary battery was calculated based on the weight of the positive active material.

[0508] The cycle characteristics of cells (Cel_11) to (Cel_13) at 45℃ are shown in (A) of FIG. 28, the cycle characteristics of cells (Cel_14) to (Cel_16) are shown in (B) of FIG. 28, the cycle characteristics of cells (Cel_17) to (Cel_20) are shown in (A) of FIG. 29, and the cycle characteristics of cells (Cel_21) to (Cel_23) are shown in (B) of FIG. 29.

[0509] According to Figures 28 (A) and (B), in a cell using an ionic liquid as the electrolyte, the decrease in discharge capacity was very small even at a charging voltage of 4.45 V. On the other hand, in a cell using an organic electrolyte, the discharge capacity began to decrease at a charging voltage of 4.45 V.

[0510] According to (A) of FIG. 29, when the charging voltage is set to 4.5V, the discharge capacity decreases gradually even in cells using an ionic liquid as the electrolyte. Meanwhile, according to (A) and (B) of FIG. 24, good characteristics were obtained even when the charging voltage was set to 4.5V at 25℃. Therefore, it is suggested that by controlling the charging voltage according to the temperature range used, the decrease in discharge capacity due to the use of the secondary battery can be suppressed, and the secondary battery can be made long-life.

[0511] In addition, looking at (B) of FIG. 29, it can be seen that excellent cycle characteristics are obtained at a charging voltage of 4.45 V in a cell in which the loading amounts of the positive and negative active materials are increased and the type of graphite is changed.

[0512] [Evaluation of Rate Characteristics]

[0513] Next, the rate characteristics were evaluated at 10℃.

[0514] As battery cells, the cells shown in Table 4 (Cel_31 to Cel_33) were fabricated. The combinations of positive electrode, negative electrode, and electrolyte solution used, and the charge voltage are shown in Table 4.

[0515] [Table 4]

[0516]

[0517] The loading amount of the positive active material on the positive electrode (P1) is approximately 6.5 mg / cm² 2 The amount of the cathode active material loaded on the cathode (N1) was adjusted so that the capacity ratio was approximately 84% or more and 87% or less.

[0518] At the positive electrode, the area of ​​the positive active material layer formed on the current collector is 8.194 cm² 2 ...did so.

[0519] CCCV charging (0.2C, termination current 0.02C) was performed, and CC discharge (2.5V) was performed. Discharge was performed sequentially with discharge rates of 0.1, 0.2, 0.5, and 1[C]. The capacity of the secondary battery was calculated based on the weight of the positive active material.

[0520] The cycle characteristics of cells (Cel_31) to cells (Cel_33) at 10℃ are shown in (A), (B) of FIG. 30 and FIG. 31, respectively.

[0521] Looking at Figures 30 (A) and (B) and Figure 31, it can be seen that even under conditions of a relatively low temperature of 10°C, a discharge capacity of 98% or more of 0.1C is obtained at a rate of 0.5C. In addition, at a rate of 1C, Cel_31 obtained a discharge capacity of 97% or more of 0.1C, and very excellent rate characteristics were obtained. In addition, at Cel_32, the discharge capacity decreased and remained at about 60% of 0.1C. Explanation of the symbols

[0522] 111: Anode, 111a: Anode, 115: Cathode, 115a: Cathode, 121: Anode current collector, 122: Anode active material layer, 123: Separator, 125: Cathode current collector, 126: Cathode active material layer, 130: Electrode assembly, 131: Electrode assembly, 211a: Anode, 211b: Cathode, 212a: Lead, 212b: Lead, 214: Separator, 250: Secondary battery, 251: Enclosure, 400: Secondary battery, 401: Anode cap, 402: Device, 402a: Housing, 402b: Secondary battery, 403: Device, 403a: Housing, 403b: Secondary battery, 405: Wristwatch-type device, 405a: Display, 405b: Belt section, 406: Belt-type device, 406a: Belt section, 406b: Wireless power supply / receiving section, 413: Conductive plate, 414: Conductive plate, 415: Energy storage system, 416: Wiring, 420: Control circuit, 421: Wiring, 422: Wiring, 423: Wiring, 424: Conductor, 425: Insulator, 426: Wiring, 490: Glasses-type device, 490a: Frame, 490b: Display section, 491: Headset-type device, 491a: Microphone section, 491b: Flexible pipe, 491c: Earphone section, 500: Secondary battery, 501: Positive current collector, 502: Positive active material layer, 503: Positive electrode, 504: Negative current collector, 505: Negative active material layer, 506: Cathode, 507: Separator, 508: Electrolyte, 509: Cap, 510: Positive lead electrode, 511: Negative lead electrode, 513: Secondary battery, 514: Terminal, 515: Seal, 517: Antenna, 519: Layer, 521: Seal, 522: Seal, 523: Seal, 529: Label, 531: Secondary battery pack, 540: Circuit board, 551: One side, 552: The other side, 590: Control circuit, 590a: Circuit system, 590b: Circuit system, 601: Positive cap, 602: Battery can, 603: Positive terminal, 604: Positive electrode, 605: Separator, 606: Cathode, 607: Negative terminal, 608: Insulating plate, 609: Insulating plate,611: PTC (Positive Temperature Coefficient) element, 613: Safety valve mechanism, 730: Charge control circuit, 900: Circuit board, 910: Label, 911: Terminal, 912: Battery control circuit, 913: Secondary battery, 914: Antenna, 915: Thread, 916: Layer, 917: Layer, 918: Antenna, 920: Display device, 921: Sensor, 922: Terminal, 930: Housing, 931: Cathode, 932: Anode, 933: Separator, 950: Wound body, 951: Terminal, 952: Terminal, 971: Electrode, 972: Electrode, 981: Film, 982: Film, 1700: Curved surface, 1701: Flat surface, 1702: Curve, 1703: Radius of curvature, 1704: Center of curvature, 1800: Center of curvature, 1801: Film, 1802: Radius of curvature, 1803: Film, 1804: Radius of curvature, 7000: Robot, 7100: Portable display device, 7101: Housing, 7102: Display unit, 7103: Operation button, 7104: Battery, 7120: Aircraft, 7140: Robot vacuum cleaner, 7160: Electric vehicle, 7200: Portable information terminal, 7201: Housing, 7202: Display unit, 7203: Band, 7204: Buckle, 7205: Operation button, 7206: Input / Output terminal, 7207: Icon, 7210: Smartphone, 7220: PC, 7240: Game console, 7260: Game console, 7262: Controller, 7300: Display device, 7304: Display unit, 7400: Mobile phone, 7401: Housing, 7402: Display unit, 7403: Operation button, 7404: External connection port, 7405: Speaker, 7406: Microphone, 7407: Storage battery, 7408: Control circuit, 7500: Electronic cigarette, 7501: Atomizer, 7504: Secondary battery, 8000: Display device, 8001: Housing, 8002: Display unit, 8003: Speaker unit, 8004: Secondary battery, 8005: Voice input device, 8007: Speaker, 8008: Display unit, 8009: Portable information terminal, 8010: Charging module,8021: Charging device, 8022: Cable, 8024: Storage system, 8100: Lighting device, 8101: Housing, 8102: Light source, 8103: Secondary battery, 8104: Ceiling, 8105: Side wall, 8106: Floor, 8107: Window, 8200: Indoor unit, 8201: Housing, 8202: Air vent, 8203: Secondary battery, 8204: Outdoor unit, 8300: Electric freezer / refrigerator, 8301: Housing, 8302: Refrigerator door, 8303: Freezer door, 8304: Secondary battery, 8400: Automobile, 8401: Headlight, 8406: Electric motor, 8500: Automobile, 8600: Scooter, 8601: Side mirror, 8602: Energy storage system, 8603: Turn signal, 8604: Storage compartment under the seat, 8700: Electric bicycle, 8701: Battery, 8702: Energy storage system, 8703: Display unit, 8704: Control circuit, 9600: Tablet-type terminal, 9601: Laptop-type personal computer, 9625: Switch, 9626: Switch, 9627: Power switch, 9628: Operation switch, 9629: Locking unit, 9630: Housing, 9630a: Housing, 9630b: Housing, 9630B: Housing, 9631: Display unit, 9633: Solar cell, 9634: Control circuit, 9635: Energy storage, 9640: Moving unit, 9650: Keyboard unit,

Claims

Claim 1 A secondary battery comprising a positive electrode, a negative electrode, an electrolyte, and an outer casing, wherein the positive electrode comprises a positive active material, wherein the positive active material comprises lithium, cobalt, oxygen, magnesium, and fluorine, wherein the number of atoms of magnesium included in the positive active material is 0.001 times or more and 0.1 times or less the number of atoms of cobalt included in the positive active material, wherein the positive active material comprises a region having a layered rock salt-type crystal structure, wherein the electrolyte comprises an ionic liquid and LiFSA (lithium bis(fluorosulfonyl)amide), wherein the ionic liquid comprises a compound represented by the general formula (G11), A secondary battery comprising a metal layer and a polymer layer laminated on the metal layer, wherein the polymer layer includes a region in contact with the electrolyte. Claim 2 delete Claim 3 delete Claim 4 delete Claim 5 delete Claim 6 delete Claim 7 delete Claim 8 delete Claim 9 delete Claim 10 A secondary battery comprising a positive electrode, a negative electrode, an electrolyte, and an outer casing, wherein the positive electrode comprises a positive active material, wherein the positive active material comprises lithium, cobalt, oxygen, magnesium, and fluorine, wherein the positive active material comprises a region having a layered rock salt-type crystal structure, wherein the electrolyte comprises an ionic liquid and LiFSA (lithium bis(fluorosulfonyl)amide), wherein the ionic liquid comprises a compound represented by the general formula (G11), A secondary battery comprising: an outer body including a metal layer and a polymer layer laminated on the metal layer, wherein the polymer layer includes a region in contact with the electrolyte, wherein the negative electrode includes graphite, and wherein, when the positive electrode is analyzed by powder X-ray diffraction using CuKα1 line after performing constant current charging until the battery voltage reaches 4.5V and constant voltage charging until the current value reaches 0.01C in a 25℃ environment, the positive electrode has diffraction peaks at 2θ greater than 19.10° and less than 19.50° and 2θ greater than 45.45° and less than 45.65°, respectively. Claim 11 delete Claim 12 delete Claim 13 delete Claim 14 delete Claim 15 delete Claim 16 delete

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