Power storage device

Abstract

To provide a power storage device which is small in degradation in charge / discharge characteristics owing to a heat treatment, or a power storage device which is high in safety during a heating process.SOLUTION: A power storage device comprises a positive electrode, a negative electrode, a separator, an electrolyte, and an outer packaging body. The separator is located between the positive and negative electrodes, and contains polyphenylene sulfide or cellulose fiber. The electrolyte contains propylene carbonate, ethylene carbonate, vinylene carbonate, lithium hexafluorophosphate, and lithium bis(pentafluoroethanesulfonyl)amide. The concentration of the lithium hexafluorophosphate is 0.01 wt.% or more and 1.9 wt.% or less in weight percentage to the electrolyte.SELECTED DRAWING: Figure 43

Description

[Technical Field]

[0001] One embodiment of the present invention relates to a power storage device and an electronic device.

[0002] Note that one embodiment of the present invention is not limited to the above technical fields. One aspect relates to a process, a machine, a method of manufacture. It relates to the composition of matter. More specifically, the technical field of one embodiment of the invention disclosed in this specification is a semiconductor device, a display device, , light-emitting device, power storage device, storage device, imaging device, driving method thereof, or manufacturing method thereof - Patents.com can be cited as an example.

[0003] In this specification, the term "power storage device" refers to elements and devices in general that have a power storage function. For example, a storage battery (also called a secondary battery) such as a lithium-ion secondary battery, This includes lithium ion capacitors and electric double layer capacitors. [Background technology]

[0004] In recent years, various types of energy storage devices such as lithium-ion secondary batteries, lithium-ion capacitors, and air batteries have become available. In particular, lithium-ion batteries, which have high output and high energy density, are being developed. The secondary battery is used in mobile phones, smartphones, laptops, and other portable information terminals. , portable music players, digital cameras, medical equipment, or hybrid vehicles (HEVs), Next-generation clean electric vehicles (EV) or plug-in hybrid vehicles (PHEV) Demand for energy vehicles and other products is rapidly expanding along with the development of the semiconductor industry, and As a source of renewable energy, it has become indispensable in today's information society.

[0005] As described above, lithium ion secondary batteries are used in a variety of fields and applications. The characteristics required for lithium-ion secondary batteries are high energy density and high cycle characteristics. These include reliability, and safety in various operating environments.

[0006] A lithium ion secondary battery has at least a positive electrode, a negative electrode, and an electrolyte ( Patent document 1). [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-9418 Summary of the Invention [Problem to be solved by the invention]

[0008] When the power storage device is installed in an electronic device such as a wearable device or a portable information terminal, In particular, the housing of the electronic device must be able to withstand the heat treatment that accompanies the processing of the device. When the battery is formed integrally with the housing, the housing must be heat resistant to a temperature equal to or higher than the manufacturing temperature of the housing.

[0009] In order to improve the heat resistance of the electricity storage device, the electrolyte must have high heat resistance. To improve the performance, it is necessary to suppress the decomposition of the electrolyte by heat or to dissolve the electrolyte in other substances by heat. It is thought that the reaction between the electrolyte and other components will be effective in preventing the electrolyte from decomposing. The reaction with the component may be, for example, a reaction with the positive electrode, negative electrode, separator, or exterior body.

[0010] In view of the above, one embodiment of the present invention provides a power storage device in which deterioration of charge and discharge characteristics due to heat treatment is small. Another object of one embodiment of the present invention is to provide a method for improving safety in heat treatment. Another object of one embodiment of the present invention is to provide a highly flexible power storage device. Another object of the present invention is to provide a power storage device. One of the objectives is to provide electronic devices, etc.

[0011] The description of these problems does not preclude the existence of other problems. It is not necessary for the present invention to solve all of these problems. The above will be made clear from the description, drawings, claims, etc. It is possible to extract other issues from the descriptions in the patent, claims, etc. [Means for solving the problem]

[0012] One aspect of the present invention is a battery comprising a positive electrode, a negative electrode, a first separator, an electrolyte, and an outer casing. The positive electrode includes a positive electrode active material layer and a positive electrode current collector, and the negative electrode includes a negative electrode active material layer and a negative electrode current collector. a first separator positioned between the positive electrode and the negative electrode, the first separator , polyphenylene sulfide or cellulose fibers, and the electrolyte is propylene carbonate. ester, ethylene carbonate, vinylene carbonate, lithium hexafluorophosphate and The power storage device includes a lithium salt represented by the general formula (G1).

[0013] [ka]

[0014] In the general formula (G1), R1 and R2 each independently represent fluorine or a linear, branched or It represents a cyclic fluoroalkyl group having 1 to 10 carbon atoms.

[0015] The above-mentioned power storage device further comprises a second separator, and the second separator is The second separator is located between one or more of the negative electrodes and the outer casing, and is made of polyphenylene sulfide. It is preferred that the material contains sulfide or cellulose fibers.

[0016] In the above-mentioned electricity storage device, the weight ratio of lithium hexafluorophosphate to the electrolyte is 0.01 The concentration is preferably 1.9 wt% or more and 1.9 wt% or less.

[0017] In the above-mentioned power storage device, the lithium salt represented by the general formula (G1) is lithium bis(pentyl)- Preferably, the compound is tetrafluoroethanesulfonyl amide.

[0018] In the above-described electricity storage device, the positive electrode current collector preferably contains aluminum or stainless steel. Desirable.

[0019] One embodiment of the present invention is a power storage device including the above-described power storage device, a band, a display panel, and a housing. the device has a positive lead and a negative lead, the positive lead being electrically connected to the positive electrode; The negative electrode lead is electrically connected to the negative electrode, the power storage device is embedded inside the band, and the positive electrode A portion of the lead and a portion of the negative electrode lead protrude from the band, and the power storage device is flexible. The power storage device is electrically connected to the display panel, the display panel is included in the housing, and the band is The band is connected to the housing and is an electronic device including a rubber material.

[0020] In the electronic device, the rubber material is preferably fluororubber or silicone rubber. Desirable. [Effects of the Invention]

[0021] According to one embodiment of the present invention, a power storage device in which deterioration of charge-discharge characteristics due to heat treatment is small can be provided. According to one embodiment of the present invention, a power storage device that is highly safe in heat treatment can be provided. According to one embodiment of the present invention, a highly flexible power storage device can be provided. According to one embodiment, a novel power storage device, an electronic device, or the like can be provided.

[0022] The description of these effects does not preclude the existence of other effects. The embodiment does not necessarily have to have all of these effects. , the specification, drawings, claims, etc., and It is possible to extract other effects from the claims and other descriptions. [Brief explanation of the drawings]

[0023] [Figure 1] 1A and 1B illustrate an example of a power storage device and an example of an electrode. [Figure 2] FIG. 1 illustrates an example of a power storage device. [Figure 3] FIG. 1 illustrates an example of a power storage device. [Figure 4] FIG. 1 illustrates an example of a power storage device. [Figure 5] FIG. 1 illustrates an example of a power storage device. [Figure 6] FIG. 10 is a diagram showing an example of embossing. [Figure 7] FIG. 1 illustrates an example of a power storage device. [Figure 8] FIG. 1 illustrates an example of a power storage device. [Figure 9] FIG. 1 illustrates an example of a power storage device. [Figure 10] 1A to 1C illustrate an example of a method for manufacturing a power storage device. [Figure 11]1A to 1C illustrate an example of a method for manufacturing a power storage device. [Figure 12] 1A to 1C illustrate an example of a method for manufacturing a power storage device. [Figure 13] 1A to 1C illustrate an example of a method for manufacturing a power storage device. [Figure 14] 1A and 1B are diagrams illustrating examples of an electronic device, a band, and a power storage device. [Figure 15] FIG. 10 is a diagram showing an example of a band and a power storage device. [Figure 16] FIG. 1 illustrates an example of a power storage device. [Figure 17] FIG. 10 is a diagram showing an example of a method for detecting a liquid leak. [Figure 18] FIG. 1 illustrates an example of a power storage device. [Figure 19] FIG. 1 illustrates an example of a power storage device. [Figure 20] FIG. 1 illustrates an example of a power storage device. [Figure 21] 1A to 1C illustrate an example of a method for manufacturing a power storage device. [Figure 22] FIG. 1 illustrates an example of a power storage device. [Figure 23] FIG. 1 illustrates an example of a power storage device. [Figure 24] 1A to 1C illustrate an example of a method for manufacturing a power storage device. [Figure 25] FIG. 1 illustrates an example of a power storage device. [Figure 26] 1A and 1B are diagrams illustrating examples of electronic devices. [Figure 27] 1A and 1B are diagrams illustrating examples of electronic devices. [Figure 28] 1A and 1B are diagrams illustrating examples of electronic devices. [Figure 29] 1A and 1B are diagrams illustrating examples of electronic devices. [Figure 30] 1A and 1B are diagrams illustrating examples of electronic devices. [Figure 31] FIG. 2 is a diagram showing charge / discharge curves according to the first embodiment. [Figure 32] FIG. 2 is a diagram showing charge / discharge curves according to the first embodiment. [Figure 33] FIG. 2 is a diagram showing charge / discharge curves according to the first embodiment. [Figure 34] FIG. 2 is a diagram showing charge / discharge curves according to the first embodiment. [Figure 35] FIG. 2 is a graph showing cycle characteristics according to Example 1. [Figure 36] FIG. 2 is a graph showing cycle characteristics according to Example 1. [Figure 37] FIG. 2 is a graph showing cycle characteristics according to Example 1. [Figure 38] FIG. 2 is a graph showing cycle characteristics according to Example 1. [Figure 39] FIG. 2 is a graph showing cycle characteristics according to Example 1. [Figure 40] FIG. 2 is a graph showing cycle characteristics according to Example 1. [Figure 41] FIG. 2 is a graph showing cycle characteristics according to Example 1. [Figure 42] FIG. 2 is a graph showing cycle characteristics according to Example 1. [Figure 43] FIG. 2 is a graph showing the relationship between the concentration of lithium hexafluorophosphate and cycle characteristics according to Example 1. [Figure 44] FIG. 10 is a diagram showing charge / discharge curves according to Example 2. [Figure 45] FIG. 10 is a diagram showing charge / discharge curves according to Example 2. [Figure 46] FIG. 10 is a graph showing cycle characteristics according to Example 2. [Figure 47] FIG. 10 is a graph showing cycle characteristics according to Example 2. [Figure 48] FIG. 10 is a graph showing cycle characteristics according to Example 2. [Figure 49] FIG. 10 is a graph showing cycle characteristics according to Example 2. [Figure 50] FIG. 10 is a graph showing the relationship between the concentration of lithium hexafluorophosphate and cycle characteristics according to Example 2. [Figure 51] FIG. 10 is a diagram showing XPS measurement positions according to Example 3. [Figure 52] FIG. 10 is a diagram showing an XPS spectrum according to Example 3. [Figure 53] FIG. 10 is a diagram showing an XPS spectrum according to Example 3. [Figure 54] FIG. 10 is a diagram showing an XPS spectrum according to Example 3. [Figure 55] FIG. 10 is a diagram showing an XPS spectrum according to Example 3. [Figure 56] FIG. 10 shows the results of TG-DTA measurement according to Example 4. [Figure 57]FIG. 10 shows the results of TG-DTA measurement according to Example 4. DETAILED DESCRIPTION OF THE INVENTION

[0024] The embodiments will be described in detail with reference to the drawings. However, the present invention is not limited to the following description. The present invention is not limited to the above embodiments, and various changes and modifications may be made in the form and details thereof without departing from the spirit and scope of the present invention. It will be readily understood by those skilled in the art that the present invention can be achieved by the following embodiments. It should not be construed as being limited to the contents described.

[0025] In the configuration of the invention described below, the same parts or parts having similar functions are designated by the same reference numerals. The same reference numerals are used in common among different drawings, and the repeated explanations thereof will be omitted. When referring to a function, the hatch pattern may be the same and no particular symbol may be added.

[0026] In addition, the position, size, range, etc. of each component shown in the drawings are not necessarily the same as those in the actual device for ease of understanding. Therefore, the disclosed invention may not necessarily represent the actual position, size, range, etc. The position, size, range, etc. are not necessarily limited to those disclosed in the drawings, etc.

[0027] In this specification, flexibility refers to the property that an object is soft and can bend. It refers to the property that an object can deform in response to an external force applied to it, and is called elasticity or deformation. The ability to restore the original shape is not an issue. A flexible energy storage device can be easily restored to its original shape in response to external forces. The flexible power storage device can be deformed by being fixed in a deformed state. It can be used in a deformed state or repeatedly deformed. In this specification and the like, the inside of the exterior body refers to the area surrounded by the exterior body in the power storage device. This refers to the area where the positive electrode, negative electrode, active material layer, separator, and other structures, as well as the electrolyte, etc. are stored. This is an area where

[0028] The words "film" and "layer" may be used interchangeably depending on the situation. For example, the term "conductive layer" can be used interchangeably with the term "conductive film." Alternatively, for example, the term "insulating film" may be changed to " may be changed to the term "insulating layer."

[0029] (Embodiment 1) In this embodiment, a power storage device of one embodiment of the present invention will be described with reference to FIGS. 1 to 13. .

[0030] A power storage device of one embodiment of the present invention includes a positive electrode, a negative electrode, a separator, an electrolyte, and an outer casing.

[0031] In order to improve the heat resistance of the electricity storage device, the electrolyte must have high heat resistance. To improve the performance, it is necessary to suppress the decomposition of the electrolyte by heat or to dissolve the electrolyte in other substances by heat. It is thought that it is effective to suppress the decomposition of the electrolyte by reacting with other materials. The reaction may be, for example, a reaction with the positive electrode, negative electrode, separator, or exterior body.

[0032] In this specification, an electrolyte refers to a substance having electrical conductivity. The electrolyte is not limited to a liquid, but may be a gel or a solid. A liquid can be made by dissolving a solute in a solvent. A solid electrolyte is sometimes called a solid electrolyte. be.

[0033] For example, lithium hexafluoride represented by the structural formula (100) is used as the lithium salt, which is the solute of the electrolyte. However, lithium hexafluorophosphate (LiPF6) is chemically For example, it hydrolyzes with a small amount of water to generate HF, which leads to deterioration of the power storage device. It is also thought that this may be the cause of decomposition. At high temperatures, it decomposes into LiF and PF5, and PF5 becomes the solvent. It is said that this causes the decomposition of ammonium nitrate, and as a solute it is thought to have low stability at high temperatures. The thermal decomposition temperature of lithium hexafluorophosphate is about 154°C. The temperature at which the weight of the final product decreases by 5% due to thermal decomposition is shown. The amount fluctuation was measured by thermogravimetry-differential thermal analysis (TG-DTA). -Differential Thermal Analysis) etc. do.

[0034] [ka]

[0035] The lithium salt used in one embodiment of the present invention is represented by General Formula (G1).

[0036] [ka]

[0037] In the general formula (G1), R1 and R2 each independently represent fluorine or a linear, branched or cyclic group. represents a fluoroalkyl group having 1 to 10 carbon atoms.

[0038] In this specification and the like, a fluoroalkyl group refers to an alkyl group in which some or all of the hydrogen atoms are It refers to a group in which 60% or more of the hydrogen atoms in the alkyl group are substituted with fluorine atoms. The fluoroalkyl group is preferably substituted with a carbon atom such as oxygen, sulfur, or nitrogen, or a hydrogen atom. It may contain atoms other than hydrogen and fluorine.

[0039] The lithium salt represented by general formula (G1) has high chemical and thermal stability. Because of its high thermal resistance, its use as a solute can improve the heat resistance of the power storage device. In addition, the lithium salt represented by the general formula (G1) has fluorine, which has high electronegativity. Therefore, the fluoroalkylsulfonyl group exhibits strong electron-withdrawing properties, and the degree of lithium ion dissociation is very high. The value of Zn is always high, and it is difficult to use it as a solute in an electrolyte in a power storage device such as a lithium-ion secondary battery. The more fluorine atoms the fluoroalkyl group has, the more preferable it is.

[0040] In the general formula (G1), R1 is fluorine or a linear, branched or cyclic group having 1 to 7 carbon atoms. In general formula (G1), R2 is a fluorine atom or a linear alkyl group. More preferred are branched or cyclic fluoroalkyl groups having 1 to 7 carbon atoms. By using such a lithium salt as a solute in the electrolyte, the heat resistance of the power storage device can be improved. do.

[0041] In the general formula (G1), R1 is fluorine or a linear, branched or cyclic group having 1 or more carbon atoms. In general formula (G1), R2 is a fluorine or More preferably, it is a linear, branched or cyclic fluoroalkyl group having 1 to 5 carbon atoms. This increases the degree of dissociation of the lithium salt represented by general formula (G1), and the ionic conductivity In addition, the molecular weight of the lithium salt represented by the general formula (G1) can be increased. The viscosity of the electrolyte increases because the volume of the electrolyte does not increase and the weight of the electrolyte that needs to be dissolved in the solvent is small. This can prevent deterioration of battery characteristics and reduce costs.

[0042] The specific structural formula of the lithium salt represented by general formula (G1) is shown below: Structural formula (101) Lithium bis(fluorosulfonyl)amide (Li(FSO2)2N, abbreviated as: LiFSA), lithium bis(trifluoromethanesulfonyl) Li(CF3SO2)2N, abbreviated as LiTFSA, is represented by the structural formula (103). Lithium bis(pentafluoroethanesulfonyl)amide (Li(C2F5SO2 ) 2N, abbreviated as LiBETA), lithium (perfluorobenzyl) represented by the structural formula (104) (trifluoromethanesulfonyl)amide (LiN(C4F9SO2) It is preferable to use CF3SO2 as the solute. Therefore, by using lithium as a solute, the heat resistance of the electricity storage device can be improved. The melting point of bis(fluorosulfonyl)amide is 140°C, and the thermal decomposition temperature is about 300°C. The melting point of lithium bis(trifluoromethanesulfonyl)amide is 233°C, and its thermal decomposition The temperature is about 380°C. Its melting point is 328°C and its thermal decomposition temperature is around 350°C.

[0043] [ka]

[0044] However, the lithium salt represented by the general formula (G1) may react with the current collector, causing the current collector to corrode. Corrosion of the current collector can cause a decrease in battery capacity.

[0045] The lithium hexafluorophosphate represented by the structural formula (100) reacts with the current collector to form a A passive film may be formed on the surface of the current collector to inhibit corrosion of the current collector.

[0046] Therefore, in one embodiment of the present invention, the solute of the electrolyte contains a lithium salt represented by general formula (G1) and and lithium hexafluorophosphate (LiPF6) represented by structural formula (100). Lithium hexafluorophosphate (LiPF6) forms a passivation film on the surface of the current collector, It can suppress corrosion of the current collector. Lithium hexafluorophosphate (LiPF6) is formed on the surface of the current collector. It is desirable to use an amount that can form a passive film. The lithium salt mainly plays the role of supplying the lithium ions that act as carrier ions, and is heat-resistant. Furthermore, the lithium salt represented by the general formula (G1) and the lithium salt represented by the structural formula (100) By using lithium hexafluorophosphate (LiPF6), which is a highly heat-resistant energy storage device, Furthermore, even if the storage battery is subjected to heat treatment, the capacity and energy can be maintained after repeated charging and discharging. This makes it possible to provide a power storage device in which the energy density is less likely to decrease.

[0047] In addition, in order to improve the heat resistance of the electricity storage device, the solvent contained in the electrolyte has a high boiling point and a low vapor pressure. It is preferable that the solvent has a high dielectric constant and a high ability to dissolve the solute. Carbonates can be used as such solvents. Carbonates are molecules It refers to a compound that has at least one carbonate ester in its structure, and includes cyclic carbonates and chain carbonates. The term "chain" includes both linear and branched chains. Examples of the ester include ethylene carbonate (EC) represented by the structural formula (301), Propylene carbonate (PC) represented by formula (302), structural formula (303) Vinylene carbonate (VC) can be used. Ethylene carbonate (EC) The boiling point of propylene carbonate (PC) is 243°C, the boiling point of vinylene carbonate is 242°C. The boiling point of VC is 162°C, and these have high heat resistance and low vapor pressure. It is preferable to use it as a solvent.

[0048] [ka]

[0049] When the negative electrode is graphite (layered graphite), propylene carbonate (PC) forms impurities on the graphite surface. Without forming a dynamic film, the lithium ions are inserted between the graphite layers, and part of the graphite layers Therefore, the electrolyte is used to form a passivation film on the graphite surface. It is preferable to use a mixture of a solvent that has the function of forming a passivation film on the graphite surface. Examples of solvents that can form a polymer include ethylene carbonate (EC), vinylene carbonate, and the like. Therefore, in one embodiment of the present invention, propylene carbonate (VC) is used. Polycarbonate (PC), ethylene carbonate (EC) and vinylene carbonate (VC) were electrolytically This prevents some of the graphite layers from peeling off from the graphite particles. can.

[0050] Therefore, in one embodiment of the present invention, ethylene carbonate (EC), proton exchange copolymer (PEC) and propylene glycol are used as the solvent for the electrolyte. It contains polypropylene carbonate (PC) and vinylene carbonate (VC), and is the solute of the electrolyte. and lithium salts represented by general formula (G1) and lithium hexafluorophosphate (LiPF6) It is preferred that the compound has the following structure:

[0051] In the power storage device of one embodiment of the present invention, ethylene carbonate (EC) and propylene carbonate (PC) are used. Vinylene carbonate (VC) was mixed with a mixture of 1:1 volume ratio of 1:1. Lithium bis(pentafluoroethanesulfonyl)amide (LiBETA) and hexafluoroethanesulfonyl It is preferable to use an electrolyte prepared by dissolving lithium fluoride phosphate.

[0052] Specifically, vinylene carbonate (VC) is used in an amount of 0.1 wt% or more by weight relative to the electrolyte. Dissolve the lithium bis(pentyl alcohol) in an amount of 5.0 wt% or less, preferably 1.0 wt%. The tetrafluoroethanesulfonyl amide (LiBETA) is used in the electrolyte at a molar concentration of 0 Dissolve the solution in an amount of 1 mol / L or more and 5.0 mol / L or less, preferably 1 mol / L. It is preferable that the lithium hexafluorophosphate is contained in an amount of 0.01 wt% or more by weight relative to the electrolyte. The weight ratio of lithium hexafluorophosphate to the electrolyte is preferably 1.9 wt% or less. It is more preferable that the content of lithium hexafluorophosphate is 0.05 wt% or more and 1.2 wt% or less. The weight ratio of the polymer to the electrolyte is more preferably 0.1 wt % or more and 0.8 wt % or less.

[0053] The composition of the electrolyte was analyzed by X-ray photoelectron spectroscopy (XPS). on Spectroscopy), Gas Chromatography Mass Spectrometry (GC-MS:Ga s Chromatography-Mass Spectrometry), liquid chromatography Liquid Chromatography-Mass Spectrometry (LC-MS) Mass Spectrometry), ion chromatography (IC: Ion C chromatography, inductively coupled plasma optical emission spectroscopy (ICP-AE) S:Inductively Coupled Plasma Atomic Emis sion Spectroscopy), Atomic Absorption Spectroscopy (AAS) sorption spectrometry), glow discharge mass spectrometry (GD-MS: Glow Discharge Mass Spectrometry), Nuclear Magnetic Resonance (NMR: Nuclear Magnetic Resonance), Fourier transform red FT-IR (Fourier Transform Infrared Spectroscopy) This can be confirmed using techniques such as endoscopic examination.

[0054] In addition, polyethylene, polypropylene, and other materials commonly used as separators are vulnerable to heat. At high temperatures, the micropores in the separator may become clogged, causing the energy storage device to stop working.

[0055] In view of this, in the power storage device of one embodiment of the present invention, polyphenylene sulfide (PPS) Separators containing methylphenylene sulfide or separators containing cellulose fibers It is preferable to use a parameter.

[0056] The separator containing polyphenylene sulfide and the separator containing cellulose fiber are Excellent heat resistance and chemical resistance.

[0057] Also, a separator containing polyphenylene sulfide and a separator containing cellulose fiber are The reactivity of the battery with the electrolyte at high temperatures is low. Therefore, the output characteristics and charge / discharge cycle characteristics are poor. It can suppress the decline in sexual activity.

[0058] <Configuration example of power storage device> Next, a specific structure of the power storage device of one embodiment of the present invention will be described.

[0059] FIG. 1A illustrates a power storage device 500, which is a power storage device of one embodiment of the present invention. 5 illustrates a thin power storage device as an example of the power storage device 500. The electrical device is not limited to this.

[0060] As shown in FIG. 1A, the power storage device 500 includes a positive electrode 503, a negative electrode 506, a first separator, and a The power storage device 500 includes a positive electrode 507, a second separator 520, and an outer casing 509. The electrode 509 may have a lead 510 and a negative electrode lead 511. The outer periphery of the part is joined by thermocompression.

[0061] FIG. 1B shows an external view of the positive electrode 503. The positive electrode 503 includes a positive electrode current collector 501 and a positive electrode active material. It has a material layer 502 .

[0062] As shown in FIG. 1(B), the positive electrode 503 preferably has a tab region 281. A portion of the region 281 is preferably welded to the positive electrode lead 510. The tab region 281 is It is preferable that the positive electrode current collector 501 has an exposed region. By welding the positive lead 510 to the area, lower contact resistance can be achieved. In addition, in FIG. 1(B), the positive electrode current collector 501 is exposed over the entire area of ​​the tab region 281. 1, the tab region 281 may have a positive electrode active material layer 502 in a part thereof.

[0063] FIG. 1C shows an external view of the negative electrode 506. The negative electrode 506 includes a negative electrode current collector 504 and a negative electrode active material. It has a material layer 505 .

[0064] As shown in FIG. 1(C), the negative electrode 506 preferably has a tab region 282. A portion of the region 282 is preferably welded to the negative electrode lead 511. The tab region 282 is It is preferable that the negative electrode current collector 504 has an exposed region. By welding the negative electrode lead 511 to this region, the contact resistance can be made lower. In addition, in FIG. 1(C), the negative electrode current collector 504 is exposed over the entire area of ​​the tab region 282. 5, the tab region 282 may have a negative electrode active material layer 505 in a part thereof.

[0065] As shown in FIG. 1A, the first separator 507 overlaps the positive electrode 503 and the negative electrode 506. The second separator 520 overlaps the tab region 281 and the tab region 282. The second separator 520 may not be provided.

[0066] 2(A) and 2(B) are examples of cross-sectional views taken along the dashed line A1-A2 in FIG. 1(A). 2(A) and 2(B) show a pair of a positive electrode 503 and a negative electrode 506. 10A and 10B show cross-sectional structures of the fabricated power storage devices 500.

[0067] As shown in FIGS. 2A and 2B, the power storage device 500 includes a positive electrode 503, a negative electrode 506, The battery includes a first separator 507, a second separator 520, an electrolyte 508, and an outer casing 509. The first separator 507 is located between the positive electrode 503 and the negative electrode 506. The resistor 520 is disposed between the positive electrode 503 and the outer casing 509, and between the negative electrode 506 and the outer casing 509. The exterior body 509 is filled with an electrolyte 508.

[0068] The positive electrode 503 includes a positive electrode active material layer 502 and a positive electrode current collector 501. It includes an active material layer 505 and a negative electrode current collector 504. The active material layer is formed on one or both sides of the current collector. The first separator 507 is disposed between the positive electrode current collector 501 and the negative electrode current collector 504. Located.

[0069] The power storage device may have at least one positive electrode and at least one negative electrode. A laminated structure consisting of a plurality of positive electrodes and a plurality of negative electrodes may also be used.

[0070] Here, the positive electrode 503 and the negative electrode 506 are stacked together by a plurality of positive electrodes or a plurality of negative electrodes. It is preferable to have a tab area for electrical connection. It is preferable to electrically connect

[0071] An example of a cross section taken along the dashed line B3-B4 in FIG. 1(A) is shown in FIG. 3(A), and the cross section taken along the dashed line B5- An example of a cross section between B3 and B6 is shown in FIG. 3(B). The area between the dashed dotted line B3 and B4 is the positive electrode lead 510. and a cross-sectional view of a region having a positive electrode 503. The area between the dashed dotted lines B5 and B6 is a cross-sectional view of a region having a negative electrode lead 51. 3(A) and 3(B) are cross-sectional views of the area having the positive electrode 501 and the negative electrode 506. 5 shows a cross-sectional structure of a power storage device 500 fabricated using a pair of a negative electrode 503 and a negative electrode 506.

[0072] As shown in FIG. 3(A), the second separator 520 is disposed between the positive electrode 503 and the outer casing 509. The second separator 520 is provided between the tab region 281 of the positive electrode and the positive electrode lead 5. As shown in FIG. 3(B), the second separator 10 preferably has an overlapping area. The second separator 520 is provided between the negative electrode 506 and the outer casing 509. It is preferable that the electrode has a tab region 282 and a region overlapping with the negative electrode lead 511 .

[0073] The exterior body 509 is made of a material having conductivity on the outer surface of the exterior body, and the inside of the exterior body (positive and When insulating resin is used on the outer surface (the negative electrode side), the resin dissolves during heat treatment, The conductive material of the outer casing may be exposed. 510, the negative electrode lead 511, the positive electrode current collector 501, or the negative electrode current collector 504, if they come into contact with each other, leakage will occur. The second separator 520 is disposed between the positive electrode 503 and the outer casing 509, and between the negative electrode By providing the second electrode 506 between the second electrode 506 and the outer casing 509, the leakage can be suppressed. The separator 520 may not be provided.

[0074] FIG. 4(A) shows another example of a cross-sectional view taken along the dashed line A1-A2 in FIG. FIG. 4B shows a cross-sectional view taken along the dashed line B1-B2 in FIG.

[0075] 4A and 4B show a power storage device manufactured using a plurality of pairs of a positive electrode 503 and a negative electrode 506. The cross-sectional structure of the power storage device 500 is shown. There is no limitation on the number of electrode layers that the power storage device 500 has. When the number of electrode layers is large, the power storage device can have a larger capacity. When the number of electrodes is small, the power storage device can be made thin and highly flexible.

[0076] In FIGS. 4A and 4B, a positive electrode current collector 501 has a positive electrode active material layer 502 on one side thereof. Two positive electrodes 503 and a positive electrode 503 having a positive electrode active material layer 502 on both sides of a positive electrode current collector 501. and three negative electrodes 506 each having a negative electrode active material layer 505 on both sides of a negative electrode current collector 504. That is, the energy storage device 500 has six positive electrode active material layers 502 and six negative electrode active material layers 503. 4(A) and 4(B), the first separator 507 is Although a bag-shaped example is shown, the first separator 507 is not limited to this, and may be a strip-shaped or snake-shaped separator. It may be ventral.

[0077] In addition, in FIG. 4, one positive electrode having a positive electrode active material layer 502 on both sides of a positive electrode current collector 501 is 501 on one side of a positive electrode current collector 501. Similarly, one negative electrode having a negative electrode active material layer 505 on both sides of a negative electrode current collector 504 is It is preferable to replace the negative electrode with two negative electrodes each having a negative electrode active material layer 505 on one side of a negative electrode current collector 504. The electricity storage device 500 shown in FIG. 5 has a positive electrode current collector 501 to which a positive electrode active material layer 502 is attached. The surfaces of the negative electrode current collector 504 to which the negative electrode active material layer 505 is not attached are the same. With this configuration, the power storage device 500 When the electrode is bent, the interface between the two positive electrode current collectors 501 and the interface between the two negative electrode current collectors 504 This serves as a sliding surface, and stress generated inside the electricity storage device 500 can be alleviated.

[0078] In FIG. 1A, an example in which the ends of the positive electrode 503 and the negative electrode 506 are roughly aligned is shown. The electrode 503 may have a portion located outside the end of the negative electrode 506 .

[0079] In the power storage device 500, the area of ​​the negative electrode 506 that does not overlap with the positive electrode 503 is smaller. preferable.

[0080] FIG. 2A shows an example in which the end of the negative electrode 506 is located inside the positive electrode 503. By adopting such a configuration, the negative electrode 506 is entirely overlapped with the positive electrode 503, or the negative electrode 506 is The area of ​​the region that does not overlap with 503 can be reduced.

[0081] Alternatively, in the power storage device 500, the positive electrode 503 and the negative electrode 506 have approximately the same area. For example, a positive electrode 503 and a negative electrode 504 facing each other with a first separator 507 interposed therebetween are preferably For example, the areas of the first separator 507 and the second separator 6 are preferably approximately the same. The areas of the facing positive electrode active material layer 502 and negative electrode active material layer 505 are approximately the same. is preferred.

[0082] FIG. 2B shows an example in which the edge of the positive electrode 503 is located inside the negative electrode 506. By adopting such a configuration, the positive electrode 503 is entirely overlapped with the negative electrode 506, or the negative electrode The area of ​​the region that does not overlap with the negative electrode 506 can be reduced. If the electrode 506 is positioned inside the end of the negative electrode 506, the current may be concentrated at the end of the negative electrode 506. For example, current is concentrated in a part of the negative electrode 506, and lithium is deposited on the negative electrode 506. By reducing the area of ​​the region of the positive electrode 503 that does not overlap with the negative electrode 506, This can prevent current from concentrating on a part of the negative electrode 506. This is preferable because it can suppress the deposition of lithium on the O6.

[0083] As shown in FIGS. 4(A) and 4(B), when a plurality of pairs of a positive electrode 503 and a negative electrode 506 are used, In this case, the end of the positive electrode 503 may be located inside the negative electrode 506. The end of the negative electrode 506 may be aligned with the end of the positive electrode 508. It may be located inside the pole 503.

[0084] As shown in FIG. 1(A), the positive electrode lead 510 is preferably electrically connected to the positive electrode 503. Similarly, the negative electrode lead 511 is preferably electrically connected to the negative electrode 506. The positive electrode lead 510 and the negative electrode lead 511 are exposed to the outside of the exterior body 509 and electrically connected to the outside. It functions as a terminal for obtaining contact.

[0085] Alternatively, the positive electrode current collector 501 and the negative electrode current collector 504 may serve as terminals for electrical contact with the outside. In this case, the positive electrode current collector 501 and the negative electrode current collector 502 can be connected without using a lead. The electric body 504 may be arranged so that a part of the electric body 504 is exposed to the outside from the exterior body 509 .

[0086] It is preferable that part of the surface of the exterior body 509 has irregularities. By providing the protective layer 509, stress applied to the exterior body 509 when the power storage device 500 is bent can be reduced. This can improve the flexibility of the power storage device 500. The protrusions are formed by embossing the exterior body 509 before assembling the power storage device 500. It can be formed.

[0087] Here, embossing, which is a type of press working, will be explained.

[0088] Fig. 6 is a cross-sectional view showing an example of embossing. Embossing is a process of creating unevenness on the surface. An embossing roll with a pattern is pressed against the film, and the film creates irregularities that correspond to the irregularities of the embossing roll. The embossing roll is a roll with a pattern engraved on its surface. It is a rule.

[0089] FIG. 6(A) shows an example in which embossing is performed on one side of the film 50 used for the exterior body 509. be.

[0090] In FIG. 6(A), an embossing roll 53 contacts one side of the film, and an embossing roll 54 contacts the other side of the film. The film 50 is sandwiched between the roll 54 and the film 50 in the direction of film travel. The film is being sent out to 60. The pattern is formed on the surface of the film by pressure and heat. is doing.

[0091] FIG. 6(A) is also called single-sided embossing, and is performed by using an embossing roll 53 and a roll 54 (metal roll). It is a combination of rolls (rolls or elastic rolls (rubber rolls, etc.)).

[0092] In addition, in FIG. 6(B), embossing is performed once on one side between the embossing roll 53 and the roll 54. The film 51 is sandwiched and being fed in the direction of travel 60. The embossing roll 53 is in contact with the surface of the film 51 that has not yet been embossed. As the film 51 rotates, it is embossed on both sides. It is also possible to emboss the film multiple times.

[0093] FIG. 6(C) shows an enlarged cross section of film 52 which is embossed on both sides. H1 indicates the film thickness at the concave or convex part of the film. H2 is The thickness of the boundary between a recess and a protrusion adjacent to the recess, or the thickness of the boundary between a protrusion and a recess adjacent to the protrusion The film thickness is not uniform, and H2 is the thickness of the film at the boundary of the film. is smaller than.

[0094] FIG. 6(D) shows another example in which embossing is performed on both sides of the film.

[0095] In FIG. 6(D), an embossing roll 53 contacts one side of the film, and the other side The film 50 is sandwiched between the embossing roll 55 which is in contact with the film 50. The image shows the sheet being sent out in the direction of travel 60.

[0096] FIG. 6(D) shows the embossing roll 53, which is a male embossing roll, and the embossing roll 54, which is a female embossing roll. The combination of 55 and embossing the surface of the film 50. The surface is debossed to form a continuous pattern on the surface of the film 50. is doing.

[0097] FIG. 6(E) shows a case where the pitch of the protrusions formed on one embossing roll 55 in FIG. 6(D) is changed. An embossing roll 56 is used. Here, the pitch of the protrusions or the pitch of the embossing is means the distance between the vertices of adjacent protrusions. For example, the distance P in Figure 6(E) is This is called the pitch of the protrusions or the pitch of the embossing. The film 50 is sandwiched between boss rolls 56 and is being fed in the direction of travel 60. By changing the pitch of the projections, it is possible to create embossing on both sides of the film with different pitches. It is possible.

[0098] In FIG. 6(F), an embossing roll 57 contacts one side of the film, and the other side The film 50 is sandwiched between the embossing roll 58 in contact with the film 50. The image shows the sheet being sent out in the direction of travel 60.

[0099] Figure 6(F) is also called Tip to Tip double-sided embossing, and is done by using an embossing roll 5 7 and the embossing roll 58 having the same pattern as the embossing roll 57. The phases of the convex and concave portions of the embossing roll are matched, and there is a difference in the front and back of the film 50. Unlike Fig. 6(F), the same embossing pattern can be formed. Embossing can also be performed without aligning the phases of the convex and concave portions of the roll.

[0100] Furthermore, the method is not limited to using an embossing roll, and an embossing plate may also be used. In addition, the present invention is not limited to embossing, and any other processing may be used as long as a relief is formed on a part of the film. stomach.

[0101] An example of the electricity storage device 500 using the exterior body 529 on which the above-described embossing process is performed to form the unevenness This is shown in Fig. 7(A). Also, Fig. 7(B) shows the cross section between the dashed dotted line H1 and H2 in Fig. 7(A). The configuration of Fig. 7(B) except for the exterior body 529 is the same as that of Fig. 4(B).

[0102] The unevenness of the exterior body 529 is formed so as to include the areas overlapping with the positive electrode 503 and the negative electrode 506. In FIG. 7(A), no unevenness is formed on the bonding portion 518, but if the bonding portion 518 has unevenness, A protrusion may be formed.

[0103] The unevenness of the exterior body 529 is formed in the longitudinal direction of the power storage device 500 (the Y direction shown in FIG. 7(A)). ) are periodically formed. In other words, one recess and one protrusion are formed periodically on the The irregularities are formed so as to extend in the minor axis direction (the X direction shown in FIG. 7(A)). By having this, it is possible to reduce the stress applied when the power storage device 500 is bent in the longitudinal direction. .

[0104] The unevenness of the exterior body 529 allows the geometric pattern of two intersecting diagonal lines to be visually recognized. The unevenness may be formed in such a manner as to increase the 500 can relieve stress occurring in at least two directions of bending.

[0105] In addition, in FIG. 1(A), the positive electrode lead 510 and the negative electrode lead 511 are connected to the same As shown in FIG. 9, the positive electrode lead 510 and the negative electrode lead 511 are arranged on the side of the The power storage device of one embodiment of the present invention may be arranged on different sides of the device 500. Since the nodes can be freely arranged, the degree of freedom in design is high. The degree of freedom in designing a product using a power storage device can be increased. The productivity of products using the device can be increased.

[0106] <Example of manufacturing method of power storage device> Next, an example of a method for manufacturing a power storage device 500, which is a power storage device of one embodiment of the present invention, will be described with reference to FIGS. This will be explained using FIG.

[0107] First, the positive electrode 503, the negative electrode 506, and the first separator 507 are laminated. A first separator 507 is placed on the positive electrode 503. Then, the first separator 507 When two or more pairs of positive and negative electrodes are used, the negative electrode 506 is further placed on the positive electrode 506. After placing the first separator 507 on top, the positive electrode 503 is placed. The cathode 503 and the anode 506 are interposed with the separator 507 sandwiched between them. Stack them on top of each other.

[0108] Alternatively, the first separator 507 may be in a bag shape. This is preferable because it makes the electrode less susceptible to damage during the manufacturing process.

[0109] First, the positive electrode 503 is placed on the first separator 507. Then, the first separator 507 is 10(A) and fold the positive electrode 503 with the first separator 507. Here, an example in which the positive electrode 503 is sandwiched between the first separators 507 has been described. The negative electrode 506 may be sandwiched between a first separator 507 .

[0110] Here, the outer peripheral portion of the first separator 507 on the outside of the positive electrode 503 is joined to form the first separator It is preferable that the separator 507 is bag-shaped (or envelope-shaped). The outer periphery of the 07 may be joined using adhesive, ultrasonic welding, or heating. This may be done by fusion bonding.

[0111] Next, the outer periphery of the first separator 507 is bonded by heating. In this way, the positive electrode 503 can be covered with the first separator 507. do.

[0112] When the outer periphery of the first separator 507 is bonded using an adhesive, the amount of adhesive is The number of electrodes sandwiched between the first separator 507 (see FIG. 10(A)) is preferably small. In this case, the outer periphery of the positive electrode 503 may be joined so that it does not protrude from the first separator 507. Therefore, for example, by forming a joint 514 as shown in FIG. 10(B), the amount of adhesive can be reduced. In FIG. 10(B), the folded portion of the outer periphery of the first separator 507 can be reduced. The areas near the crease on the two sides that intersect with the edge where the crease is formed, and the edge opposite the edge where the crease is formed A joint 514 is formed in a part of the substrate.

[0113] Next, as shown in FIG. 10(C), the negative electrode 506, the positive electrode 503 covered with the separator, In addition, the positive electrode lead 510 and the negative electrode lead 511 having the sealing layer 115 are stacked alternately. Preparation The sealing layer 115 can be made of a thermoplastic resin such as polypropylene.

[0114] Next, as shown in FIG. 11(A), a sealing layer 115 is formed on the tab region 281 of the positive electrode 503. A positive electrode lead 510 is connected to the junction 512. An enlarged view of the connection is shown in FIG. Ultrasonic waves are applied while applying pressure to the tab region 281 of the positive electrode 503 and the positive electrode lead 510. At this time, a curved portion 513 is provided in the tab region 281. It is good.

[0115] By providing the curved portion 513, it is possible to prevent the power storage device 500 from being subjected to external force after fabrication. Therefore, the reliability of the power storage device 500 can be improved. do.

[0116] Using a similar method, the tab area 282 of the negative electrode 506 and the negative electrode lead 511 are electrically connected. It can be connected.

[0117] Next, the positive electrode 503, the negative electrode 506, and the first separator 50 are placed on the second separator 520. Place 7.

[0118] Next, the second separator 520 is folded at the portion indicated by the dashed line near the center of FIG. 11(C), and the second separator 520 is folded at the portion indicated by the dashed line near the center of FIG. The positive electrode 503, the negative electrode 506, and the first separator 507 are sandwiched between two separators 520. The second separator 520 is configured to cover the tab region 281 and the tab region 282. This is preferable.

[0119] Here, the outer periphery of the second separator 520 is joined to form the second separator 520 in a bag shape. (or envelope-shaped) is preferable. In this case, adhesive may be used, or ultrasonic welding or heat fusion may be used. Good too.

[0120] Next, the outer periphery of the second separator 520 is bonded by heating. In this way, the positive electrode 503, the negative electrode 506, and the first separator 507 are It may be covered with a second separator 520 .

[0121] When the outer periphery of the second separator 520 is bonded using an adhesive or the like, the amount of adhesive is The positive electrode 503, the negative electrode 506, and the second separator 520 are sandwiched between them. The outer periphery of the first separator 507 is joined so that it does not protrude from the second separator 520. For example, by forming a joint 521 as shown in FIG. 12(B), the adhesive In FIG. 12(B), the amount of the agent can be reduced. That is, the vicinity of the fold on the two sides intersecting with the side on which the fold is formed, the tab area 281 and the tab area A joint 521 is formed in the vicinity of 282.

[0122] The second separator 520 may not be provided. If no second separator 520 is provided, the process relating to the second separator 520 may be omitted.

[0123] Next, the positive electrode 503, the negative electrode 506, the first separator 507, and the second A separator 520 is placed.

[0124] Next, the exterior body 509 is folded at the portion indicated by the broken line near the center of the exterior body 509 in FIG. 12(C). To bend.

[0125] In FIG. 13, the portion where the outer periphery of the exterior body 509 is joined by thermocompression is shown as a joint 118. The outer periphery of the exterior body 509, except for the inlet 119 for introducing the electrolyte 508, is bonded by thermocompression. During the thermocompression bonding, the sealing layer provided on the lead also melts, and the lead and the exterior body 509 are bonded. In addition, the adhesion between the outer casing 509 and the lead can be improved. can be done.

[0126] Then, a desired amount of electrolyte 508 is introduced into the inlet 1 under a reduced pressure atmosphere or an inert gas atmosphere. 19 into the exterior body 509. Finally, the inlet 119 is bonded by thermocompression. In this manner, the power storage device 500, which is a thin power storage device, can be manufactured. .

[0127] After the power storage device 500 is manufactured, aging may be performed. Examples of aging conditions include First, charge at a rate between 0.001C and 0.2C. The temperature may be, for example, between room temperature and 50°C. At this time, the electrolyte decomposes and the gas When gas is generated, if the gas accumulates between the electrodes, the electrolyte may come into contact with the electrode surface. In other words, the effective reaction area of ​​the electrode decreases, and the effective resistance This corresponds to a higher resistance.

[0128] If the resistance becomes too high, the negative electrode potential will drop, causing lithium to be intercalated into the graphite. At the same time, lithium is precipitated on the graphite surface. This lithium precipitation leads to a decrease in capacity. For example, if a film or the like grows on the surface after lithium is deposited, The lithium deposited on the surface cannot be re-eluted, resulting in lithium that does not contribute to capacity. In addition, if the deposited lithium physically collapses and loses electrical contact with the electrode, Therefore, the negative electrode potential increases due to the rise in the charging voltage. It is preferable to vent the gas so that the potential does not reach the um potential.

[0129] To release the gas, for example, a part of the exterior body of the thin electricity storage device may be cut and opened. If the exterior body has expanded due to gas, it is preferable to reshape the exterior body. If necessary, electrolyte may be added before resealing. In this case, a space for gas evacuation is provided inside the cell to allow the gas accumulated between the electrodes to evacuate from between the electrodes. The space created by using the embossed laminate exterior described above can be used It can also be used as a space for gas evacuation.

[0130] After degassing, the mixture is heated to a temperature higher than room temperature, preferably 30°C or higher and 60°C or lower. More preferably, the temperature is 35°C or higher and 50°C or lower, for example, 1 hour or higher and 100 hours or lower. It may be kept in a charged state. During the initial charging, the electrolyte decomposed on the surface forms a film. Therefore, for example, by keeping the temperature higher than room temperature after degassing, It is also possible that the coating may become denser.

[0131] Here, the charge and discharge rates will be explained. The charge rate is the rate at which a constant voltage is applied to the battery capacity. It refers to the relative value of the current during charging, that is, the current value during charging [A] ÷ battery capacity [Ah]. It is also called C rate. The unit is C. For example, if a battery with a capacity of 10 Ah is charged at a rate of 2 A, When charging with a current, it is said to be charging at a rate of 0.2C. What is a 1C charging rate? , the current is enough to charge the battery to its full capacity in one hour. The higher the charge rate, It indicates a fast charging speed. The discharge rate is the ratio of the discharge current to the battery capacity. The relative value of the current, that is, the current value during discharge [A] ÷ battery capacity [Ah], is the C rate. It is also called "charge current." It is expressed in units of C. For example, a battery with a capacity of 10 Ah is discharged at a constant current of 2 A. If the battery is discharged at a rate of 0.2C, it is said to be discharged at a rate of 0.2C. A discharge rate of 1C is the total discharge rate of the battery. This is the amount of current required to discharge the capacity in one hour. The higher the discharge rate, the faster the discharge rate. This indicates that the speed is fast.

[0132] <Components of the power storage device> Components of a power storage device according to one embodiment of the present invention will be described in detail below. When a flexible material is selected from the materials of each member shown in the figure, a flexible A power storage device can be manufactured.

[0133] ≪Electrolyte≫ The electrolyte comprises a solute and a solvent.

[0134] The solvent for the electrolyte is a material that allows carrier ions to move. In the power storage device of one embodiment of the present invention, a solvent having low reactivity with a graphite negative electrode is preferable. A mixture of vinylene carbonate, ethylene carbonate and vinylene carbonate is dissolved in Used as a medium.

[0135] The solvent is preferably an aprotic organic solvent, such as propylene carbonate or ethylene carbonate. In addition to vinyl carbonate and vinylene carbonate, butylene carbonate, γ-butyrolactone , γ-valerolactone, dimethyl sulfoxide, methyl diglyme, benzonitrile, Use one of these or two or more of these in any combination and ratio. can be done.

[0136] In addition, by using a polymer material that gels as a solvent for the electrolyte, safety against leakage etc. is improved. The safety of the electricity storage device is improved. In addition, the thickness and weight of the electricity storage device can be reduced. Typical examples of materials include silicone gel, acrylic gel, acrylonitrile gel, and polyethylene gel. Polypropylene oxide gel, polypropylene oxide gel, fluorine polymer gel, etc. be.

[0137] In addition, ionic liquids (also known as room-temperature molten salts), which are flame-retardant and difficult to evaporate, are used as electrolyte solvents. ) is used to prevent the internal temperature from rising due to an internal short circuit or overcharging of the storage device. Even if the temperature rises, the electricity storage device can be prevented from exploding or catching fire. This can improve safety.

[0138] The solute is a substance that can move carrier ions and has carrier ions. When the carrier ion is lithium ion, the solute is lithium ion. The lithium salts used are LiBETA, which has high heat resistance, and lithium bis( Trifluoromethanesulfonylamide (Li(CF3SO2)2N, abbreviated as LiTFS) A), lithium bis(fluorosulfonyl)amide (Li(FSO2)2N, abbreviated as Li FSA), LiBF4, Lithium bis(oxalato)borate (LiB(C2O4)2 , abbreviated as LiBOB), etc. are preferred.

[0139] In the battery reaction in the electricity storage device, the electrolyte reacts with the positive electrode current collector and becomes When the metal contained in the battery elutes, the capacity of the battery decreases, and the battery deteriorates. When a cycle characteristic test was conducted on an electrical device, the capacity decreased significantly with each charge and discharge, and the device had a short life. Furthermore, if the elution of the current collector at the connection point with the lead progresses, it may lead to disconnection. Therefore, in one embodiment of the present invention, the solute material contained in the electrolyte reacts with the current collector. A material is used that suppresses the reaction and the elution of metals from the current collector.

[0140] Examples of the metal in the positive electrode current collector material include aluminum and stainless steel. In one embodiment of the present invention, the solute material used in the electrolyte is selected from the positive electrode current collectors of these metals. Specifically, a solute that can suppress elution from the surface of the polymer is used. The solute includes, as the lithium salt, the lithium salt represented by the general formula (G1) described above, and hexafluoride. Examples include lithium phosphate (LiPF6).

[0141] In a power storage device according to one embodiment of the present invention, elution of metal from a positive electrode current collector into an electrolyte is suppressed. This prevents deterioration of the positive electrode current collector and also prevents metal deposition on the negative electrode surface, improving the capacity. Therefore, the power storage device can have a small deterioration in capacity and a good cycle life.

[0142] In addition to the above solutes, other solutes include, for example, LiPF6, LiClO4, LiAsF6, and LiAl Cl4, LiSCN, LiBr, LiI, Li2SO4, Li2B 10 Cl 10 , Li2 B 12 Cl 12, LiCF3SO3, LiC4F9SO3, LiC(CF3SO2)3, LiC(C2F5SO2)3, LiN(FSO2)2, LiN(CF3SO2)2, Li Lithium salts such as N(C2F5SO2)2, LiN(C4F9SO2)(CF3SO2) One or more of them can be used in any combination and ratio.

[0143] In the above solute, the carrier ion is lithium ion. Carrier ions other than lithium ions can also be used. As carrier ions, in the case of alkali metal ions and alkaline earth metal ions, In the lithium salt, an alkali metal (e.g., sodium) is used instead of lithium. alkaline earth metals (e.g., calcium, strontium, barium, etc.), , beryllium, or magnesium, etc.) may also be used.

[0144] In addition, the electrolyte is vinylene carbonate (VC), propane sultone (PS), tert- Butylbenzene (TBB), fluoroethylene carbonate (FEC), lithium bis( oxalate) borate (LiBOB), or dinitriles such as succinonitrile and adiponitrile Additives such as nitrile compounds may be added. The concentration of the additives may be, for example, The content should be between 0.1 wt% and 5 wt%.

[0145] The above-described solvent and solute can be used to form an electrolyte for the power storage device of one embodiment of the present invention. can be done.

[0146] <Current collector> The current collector may be any suitable material, as long as it exhibits high electrical conductivity without causing significant chemical changes within the storage device. There is no limitation. The positive electrode current collector and the negative electrode current collector may be made of, for example, stainless steel, gold, platinum, zinc, or iron. , nickel, copper, aluminum, titanium, tantalum, manganese and other metals, and their alloys, Alternatively, copper or stainless steel may be used. It may be coated with carbon, nickel, titanium, or the like. Al alloys with added elements that improve heat resistance, such as neodymium, scandium, and molybdenum. Aluminum alloys can be used, or react with silicon to form silicides. The current collector may be formed of a metal element. A metal element that reacts with silicon to form a silicide. These include zirconium, titanium, hafnium, vanadium, niobium, tantalum, and chromium. , molybdenum, tungsten, cobalt, nickel, etc.

[0147] Irreversible reactions may occur between the surface of the positive electrode current collector and the surface of the negative electrode current collector and the electrolyte. Therefore, it is preferable that the positive electrode current collector and the negative electrode current collector have low reactivity with the electrolyte.

[0148] The positive electrode current collector and the negative electrode current collector are each in the form of a foil, a plate (sheet), a mesh, a cylinder, or the like. Shape: sheet, coil, punched metal, expanded metal, porous, and nonwoven fabric Furthermore, the adhesiveness to the active material layer can be improved. To achieve this, the positive electrode current collector and the negative electrode current collector may each have fine irregularities on their surfaces. The thickness of the positive electrode current collector and the negative electrode current collector is 5 μm or more and 30 μm or less. It is recommended to use the following.

[0149] An undercoat layer may be provided on a part of the surface of the current collector. This is to reduce the contact resistance between the current collector and the active material layer and to improve the adhesion between the current collector and the active material layer. The undercoat layer does not have to be formed on the entire surface of the current collector. The undercoat layer may be formed in an island shape (partially). The undercoat layer may be made of, for example, a carbon material. Examples of carbon materials include graphite and carbon black such as acetylene black. Carbon nanotubes, etc. can be used as the undercoat layer. Metal layers, layers containing carbon and polymers, and layers containing metal and polymers can also be used. .

[0150] ≪Active material layer≫ The active material layer contains an active material. The active material is a material that is involved in the insertion and desorption of ions, which act as carriers. In this specification, the layer containing the active material is called the active material layer. In addition to the active material, the active material may contain a conductive aid and a binder.

[0151] The positive electrode active material layer contains one or more positive electrode active materials. The negative electrode active material layer contains one or more negative electrode active materials. It has an active material.

[0152] The positive electrode active material and the negative electrode active material play a central role in the battery reaction of the energy storage device and are the carrier ions. To extend the life of the power storage device, the active material must be able to absorb and release charge. It is preferable that the capacity of the material involved in the irreversible reaction is small, and that the material has high charge / discharge efficiency. It is preferable that

[0153] The positive electrode active material may have, for example, a layered rock salt crystal structure or a spinel crystal structure. A composite oxide or the like can be used. In addition, as the positive electrode active material, for example, a polyanion-based The positive electrode material can be, for example, an olivine-type polyanion. Examples of the positive electrode active material include materials with a crystalline structure and Nasicon-type materials. For example, a cathode material containing sulfur can be used.

[0154] Various composite oxides can be used as the positive electrode active material. iCoO2, LiNiO2, LiMn2O4, Li2MnO3, V2O5, Cr2O5, Compounds such as MnO2 can be used.

[0155] As a material with a layered rock salt type crystal structure, for example, a composite oxide represented by LiMO2 is used. The element M is preferably at least one selected from Co and Ni. LiCoO2 has a large capacity, is stable in air, and is relatively thermally stable. In addition, the element M is preferably selected from Co and Ni. In addition to one or more of these, it may contain one or more selected from Al and Mn.

[0156] For example, LiNi x Mn y Co z O w (x, y, z and w are respectively, for example, x=y=z = 1 / 3 or its vicinity, w = 2 or its vicinity) can be used. , LiNi x Mn y Co z O w (x, y, z and w are respectively, for example, x=0.8 or its vicinity, y=0.1 or its vicinity, z=0.1 or its vicinity, w=2 or its vicinity For example, LiNi x Mn y Co z O w (x, y, z and w are, for example, x=0.5 or its vicinity, y=0.3 or its vicinity, and z=0 .2 or its vicinity, w=2 or its vicinity) can be used. iNi x Mn y Co z O w (x, y, z and w are respectively, for example, x=0.6 or (nearby, y=0.2 or nearby, z=0.2 or nearby, w=2 or nearby) For example, LiNi x Mn y Co z O w (x, y, z and For example, w is x=0.4 or its vicinity, y=0.4 or its vicinity, and z=0.2. or thereabouts, w=2 or thereabouts) can be used.

[0157] The neighborhood is, for example, a value that is greater than 0.9 times and less than 1.1 times the value.

[0158] Some of the transition metals and lithium contained in the positive electrode active material are replaced with Fe, Co, Ni, Cr, Al, Mg, etc. and materials in which one or more elements selected from Fe, Co, Ni, Cr, A material doped with one or more elements selected from Al, Mg, etc. is used as the positive electrode active material. Good too.

[0159] In addition, as the positive electrode active material, for example, a solid solution of a combination of multiple composite oxides is used as the positive electrode active material. For example, LiNi x Mn y Co z O2(x, y, z>0, x+y +z=1) and Li2MnO3 solid solution can be used as the positive electrode active material.

[0160] As an example of a material with a spinel-type crystal structure, a composite oxide represented by LiM2O4 is It is preferable to have Mn as the element M. For example, LiMnO 4 can be used. In addition, by having Ni in addition to Mn as the element M, This is preferable because it may improve the discharge voltage of the secondary battery and improve the energy density. A small amount of lithium-containing material with a spinel-type crystal structure containing manganese, such as iMn2O4, Amount of lithium nickel oxide (LiNiO2 or LiNi 1-x M x O2 (M=Co, Al, etc.) ) is preferably mixed, since it is possible to improve the characteristics of the secondary battery.

[0161] For example, the average particle size of the primary particles of the positive electrode active material is 1 nm or more and 100 μm or less. It is preferable that the thickness is 50 nm or more and 50 μm or less, and more preferable that the thickness is 1 μm or more and 30 μm or less. It is more preferable that the specific surface area is less than 1m. 2 / g or more 20m 2 / g or less The average particle size of the secondary particles is preferably 5 μm or more and 50 μm or less. The average particle size can be measured by observation using a SEM (scanning electron microscope) or a TEM, or The specific surface area can be measured by a particle size distribution analyzer using the laser diffraction and scattering method. The product can be measured by gas adsorption.

[0162] A conductive material such as a carbon layer may be provided on the surface of the positive electrode active material. For example, a carbon layer on the positive electrode active material can improve the conductivity of the electrode. The coating is formed by mixing carbohydrates such as glucose when baking the positive electrode active material. In addition, graphene, multi-graphene, and graphene oxide ( GO: Graphene Oxide) or RGO (Reduced Graphene Here, RGO can be, for example, graphene oxide (GO). ) is a compound obtained by reduction.

[0163] A layer containing one or more of an oxide and a fluoride may be provided on the surface of the positive electrode active material. The oxide may have a different composition from the positive electrode active material. That's fine.

[0164] For example, a polyanion-based positive electrode material containing oxygen, element X, metal A, and metal M may be used. The metal M can be Fe, Mn, Co, Ni, Ti, V, or N. b, the metal A is one or more of Li, Na, and Mg, and the element X is S, P, Mo, It is one or more of W, As, and Si.

[0165] Examples of materials having an olivine-type crystal structure include composite materials (general formula LiMPO4 (where M is , Fe(II), Mn(II), Co(II), Ni(II) Representative examples of the general formula LiMPO4 include LiFePO4, LiNiPO4, and Li iCoPO4, LiMnPO4, LiFe a Ni b PO4, LiFe a Co b PO4, L iFe a Mn b PO4, LiNi a Co b PO4, LiNi a Mn bPO4 (a + b is 1 Hereinafter, 0 < a < 1, 0 < b < 1), LiFe c Ni d Co e PO4, LiFe c Ni d M n e PO4, LiNi c Co d Mn e PO4 (c + d + e is 1 or less, 0 < c < 1, 0 < d < 1, 0 < e < 1), LiFe f Ni[[ID=2,7]] g Co h Mn i PO4 (f + g + h + i is 1 or less, 0 < f < 1, 0 < g < 1, 0 < h < 1, 0 < i < 1), etc., lithium compounds can be used.

[0166] In particular, LiFePO4 satisfies the requirements for a cathode active material, such as safety, stability, high capacity density, and the presence of lithium ions that can be extracted during initial oxidation (charging), in a well - balanced manner. Therefore it is preferable.

[0167] A cathode active material having an olivine - type crystal structure preferably has an average particle diameter of primary particles of 1 nm or more and 20 μm or less, more preferably 10 nm or more and 5 μm or less and even more preferably 50 nm or more and 2 μm or less. Also, the specific surface area is preferably 1 m 2 / g or more and 20 m 2 / g or less. Also, the average particle diameter of secondary particles is preferably 5 μm or more and 5 [[ID=6,0]]0 μm or less.

[0168] Also, composite materials such as the general formula Li (2-j) MSiO4 (M is one or more of Fe(II), Mn(II), Co(I I), Ni(II), 0 ≤ j ≤ 2), etc. can be used. General formula Li(2-j) As representative examples of MSiO4, 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 M n l SiO4 (where k + l is 1 or less, 0 < k < 1, 0 < l < 1), Li (2-j) Fe m Ni n Co q SiO4, Li (2-j) Fe m Ni n Mn q SiO4, Li (2-j) Ni m Co n [[ID=7)]Mn q SiO4 (where m + n + q is 1 or less, 0 < m < 1, 0 < n < 1, 0 < q < 1), Li (2-j) Fe r Ni s Co t Mn u SiO4 (where r + s + t + u is 1 or less, 0 < r < 1, 0 < s < 1, 0 < t < 1, 0 < u < 1), etc., lithium compounds can be used as materials. It is possible.

[0169] Also, A x M2(XO4)3 (A = Li, Na, Mg, M = Fe, Mn, Ti, V, Nb , X=S, P, Mo, W, As, Si) Nasicon-type compounds include Fe2(MnO4)3, Fe2(SO4)3, Li3Fe2(PO4)3, etc. Also, as a positive electrode active material, Li2MPO4F, Li Use compounds represented by the general formula 2MP2O7, Li5MO4 (M = Fe, Mn) can be done.

[0170] In addition, polyanionic positive electrode materials containing V can be used. Representative examples include α-L iVOPO4, β-LiVOPO4, α1-LiVOPO4, LiVPO4F, LiVP O4O, LiVP2O7, LiVOSO4, Li2VOSiO4, LiVMoO6, etc. Examples include:

[0171] In addition, as the positive electrode active material, perovskite-type fluorides such as NaFeF3 and FeF3, Ti Metal chalcogenides (sulfides, selenides, tellurides) such as S2 and MoS2, LiMV Oxides with an inverse spinel crystal structure such as O4, vanadium oxides (V2O5, V6 O 13 Materials such as manganese oxides and organic sulfur compounds can be used. Cut.

[0172] In addition, the positive electrode active material is a lithium ion battery with the general formula LiMBO3 (where M is Fe(II), Mn(II), C o(II)) can be used.

[0173] In addition, the positive electrode active material is a compound having the composition formula Li a Mn b M c O d Lithium-manganese can be expressed as A manganese composite oxide can be used. Here, element M is selected from elements other than lithium and manganese. The selected metal element, silicon, or phosphorus is preferably used, and nickel is preferred. Further, when measuring the entire particle of the lithium manganese composite oxide, When the value is 0 <a / (b+c)<2、かつc>0 and 0.26≦(b+c) / d<0.5, In order to realize high capacity, it is preferable to have a crystal structure between the surface layer and the center. To obtain a lithium manganese composite oxide having regions with different crystal orientations or oxygen contents In order to obtain such a lithium manganese composite oxide, it is preferable that, for example, 1.6≦a It is preferable that c / b≦1.848, 0.19≦c / b≦0.935, and 2.5≦d≦3. Furthermore, Li 1.68 Mn 0.8062 Ni 0.318 Lithium with the formula O3 It is particularly preferable to use lithium manganese composite oxide. 1.6 8Mn 0.8062 Ni 0.318 Lithium manganese complex oxide represented by the formula O3 The ratio (molar ratio) of the amounts of raw materials is Li2CO3:MnCO3:NiO=0. Lithium manganese composite oxide formed by mixing 84:0.8062:0.318 Therefore, the lithium manganese composite oxide has the composition formula Li 1.68 Mn 0.806 2Ni 0.318 It is expressed as O3, but the composition may deviate from this.

[0174] The composition of metals, silicon, phosphorus, etc. of the entire lithium manganese composite oxide particle is, for example, For example, it can be measured using an ICP-MS (inductively coupled plasma mass spectrometer). The oxygen composition of the entire particle of the lithium manganese composite oxide can be measured by, for example, EDX (energy dispersive X-ray diffraction). ​It can be measured using X-ray analysis. It can also be used in combination with ICP-MS analysis. Determined by using valence evaluation of fused gas analysis and XAFS (X-ray absorption fine structure) analysis The lithium manganese composite oxide is a compound containing at least lithium and manganese. It refers to oxides containing chromium, cobalt, aluminum, nickel, iron, magnesium, molybdenum, and such as iridium, zinc, indium, gallium, copper, titanium, niobium, silicon, and phosphorus It may contain at least one element selected from the group consisting of:

[0175] In addition, the carrier ions are alkali metal ions other than lithium ions, alkaline earth metal ions, etc. In the case of metal ions, alkali metals (e.g., sodium) are used as the positive electrode active material instead of lithium. alkaline earth metals (e.g., calcium, strontium, barium, etc.), For example, a layered oxide containing sodium may be used. can be used.

[0176] Examples of materials containing sodium include NaFeO2 and Na 2 / 3 [Fe 1 / 2 Mn1 / 2 ]O2, Na 2 / 3 [Ni 1 / 3 Mn 2 / 3 ]O2, Na2Fe2(SO4)3, N a3V2(PO4)3, Na2FePO4F, NaVPO4F, NaMPO4 (M is F e(II), Mn(II), Co(II), Ni(II)), Na2FePO4F, Na Sodium-containing oxides such as 4Co3(PO4)2P2O7 are used as the positive electrode active material. It is possible.

[0177] In addition, lithium-containing metal sulfides can be used as the positive electrode active material. 2TiS3, Li3NbS4, etc.

[0178] As the negative electrode active material, for example, a carbon-based material, an alloy-based material, or the like can be used.

[0179] Carbon materials include graphite, easily graphitizable carbon (soft carbon), and non-graphitizable carbon (hard carbon). graphene, carbon black, etc. Examples include mesocarbon microbeads (MCMB), coke-based artificial graphite, and pitch-based artificial graphite. There are artificial graphite such as graphite and natural graphite such as spherical natural graphite. There are flaked and spherical ones.

[0180] When lithium ions are inserted into graphite (when lithium-graphite intercalation compounds are formed), It exhibits a potential as low as that of metallic lithium. This allows lithium-ion secondary batteries to operate efficiently. As mentioned above, graphite has a relatively high capacitance per unit volume. It has advantages such as small volume expansion, low cost, and higher safety compared to lithium metal. Therefore, it is preferable.

[0181] Here, we will explain about graphite material. Graphite is a material in which multiple graphene layers are bonded together by van der Waals The surface of graphite material is made up of graphene layers. The graphene layer is a plane parallel to the basal plane. The basal surface is the surface where graphite is formed (also called the edge surface or end surface). One surface of the outermost graphene layer among the graphene layers is exposed. The edges of multiple graphene layers are exposed on the edge surface. The edge surfaces of the graphite material are the main entrances and exits for the insertion and desorption of thium into the graphite material.

[0182] When graphite is used as the negative electrode active material, the electrolyte containing PC is If the graphite comes into contact with the PC, a side reaction may occur between the graphite and the PC during charging and discharging. The spherical natural graphite used as the negative electrode active material of the battery is in contact with the edge surface. In this case, a layer with lower crystallinity than the graphite layer is formed, which can suppress side reactions between graphite and PC. There is.

[0183] When the carrier ion is a lithium ion, the alloy material may be, for example, Mg, Ca , Ga, Si, Al, Ge, Sn, Pb, As, Sb, Bi, Ag, Au, Zn, Cd, Materials containing at least one of Hg, In, etc. can be used. Silicon has a higher capacity than carbon, and its theoretical capacity is 4200mAh / g. The capacity of the power storage device can be increased. Examples of the materials include Mg2Si, Mg2Ge, Mg2Sn, SnS2, V2Sn3, FeSn2, CoSn2, Ni3Sn2, Cu6Sn5, Ag3Sn, Ag3Sb, Ni 2MnSb, CeSb3, LaSn3, La3Co2Sn7, CoSb3, InSb, S bSn, etc.

[0184] In addition, the negative electrode active material is SiO, SnO, SnO2, titanium dioxide (TiO2), lithium Sodium titanium oxide (Li4Ti5O 12 ), lithium-graphite intercalation compound (Li x C6), Niobium pentoxide (Nb2O5), tungsten oxide (WO2), molybdenum oxide (MoO2 ) and other oxides can be used. Here, SiO is a compound containing silicon and oxygen. If the atomic ratio of silicon to oxygen is silicon:oxygen=α:β, α has a value close to β. Here, having a value close to the value of β means that, for example, the absolute value of the difference between α and β is close to the value of β. It is preferable that the ratio is 20% or less, and more preferably 10% or less.

[0185] In addition, the negative electrode active material is a composite nitride of lithium and transition metals, which has a Li3N structure. Li 3-x M x N (M is Co, Ni or Cu) can be used. For example, Li 2. 6Co 0.4 N3 has a large charge / discharge capacity (900mAh / g, 1890mAh / cm 3 )of This is preferable.

[0186] When a composite nitride of lithium and a transition metal is used, the negative electrode active material contains lithium ions, The positive electrode active material is a combination of materials such as V2O5 and Cr3O8 that do not contain lithium ions. Even when a material containing lithium ions is used as the positive electrode active material, By first removing the lithium ions contained in the positive electrode active material, lithium is released as the negative electrode active material. A complex nitride of ammonium and a transition metal can be used.

[0187] In addition, a material that undergoes a conversion reaction can also be used as the negative electrode active material. , cobalt oxide (CoO), nickel oxide (NiO), iron oxide (FeO), etc. A transition metal oxide that does not undergo an alloying reaction with the negative electrode active material may be used. Further materials that undergo a reaction include Fe2O3, CuO, Cu2O, RuO2, and Cr2O Third order oxide, CoS 0.89 , NiS, CuS and other sulfides, Zn3N2, Cu3N, G Nitrides such as e3N4, phosphides such as NiP2, FeP2, CoP3, FeF3, BiF3 Fluorides such as:

[0188] The average particle size of the primary particles of the negative electrode active material is preferably, for example, 5 nm or more and 100 μm or less.

[0189] The positive electrode active material layer and the negative electrode active material layer may each contain a conductive additive.

[0190] As the conductive additive, for example, a carbon material, a metal material, or a conductive ceramic material is used. In addition, a fibrous material may be used as the conductive additive. The content of the conductive additive is preferably 1 wt% or more and 10 wt% or less, and more preferably 1 wt% or more and 5 wt% or less. % or less is more preferable.

[0191] The conductive additive can form an electrically conductive network in the electrode. This allows the electrical conduction path between the negative electrode active materials to be maintained. By adding the agent, an active material layer having high electrical conductivity can be realized.

[0192] Examples of the conductive additive include natural graphite, artificial graphite such as mesocarbon microbeads, and carbon fiber. Examples of carbon fibers that can be used include mesophase pitch carbon fibers. Carbon fibers such as isotropic pitch-based carbon fibers can be used. Carbon nanofibers and carbon nanotubes can be used. The tube can be produced by, for example, vapor phase growth method. For example, carbon black (acetylene black (AB) etc.), graphite particles Carbon materials such as graphene, graphene oxide, and fullerene can be used. For example, metal powders and metal fibers such as copper, nickel, aluminum, silver, and gold, and conductive ceramics. Mixed materials and the like can be used.

[0193] Flaky graphene has excellent electrical properties, such as high conductivity, as well as flexibility and functionality. Graphene has excellent physical properties, such as mechanical strength, and is therefore used as a conductive additive. This makes it possible to increase the number of contact points and the contact area between the active materials.

[0194] Graphene allows for surface contact with low contact resistance, and is conductive even when thin. The conductivity is so high that even a small amount can efficiently form a conductive path within the active material layer.

[0195] When using an active material with a small average particle size, for example, an active material with a particle size of 1 μm or less, the specific surface area of ​​the active material In such cases, the area is large and more conductive paths are required to connect the active materials. Graphene is used, which has extremely high conductivity and can efficiently form conductive paths even in small amounts. It is particularly preferred that

[0196] The positive electrode active material layer and the negative electrode active material layer may each contain a binder.

[0197] In this specification, the binder has the function of binding or adhering active materials together, and / or Alternatively, the binder has a function of binding or adhering the active material layer and the current collector. Or, during the fabrication of the battery, the state of the binder may change. For example, the binder may be liquid, solid, or The binder may be in at least one of the following states: a liquid, a gel, etc. During battery fabrication, the monomer may change into a polymer.

[0198] For example, a water-soluble polymer can be used as the binder. For example, polysaccharides can be used. Examples of polysaccharides include carboxymethyl cellulose. (CMC), methyl cellulose, ethyl cellulose, hydroxypropyl cellulose, di Cellulose derivatives such as acetyl cellulose and regenerated cellulose, and starch are used. can be done.

[0199] In addition, styrene-butadiene rubber (SBR), styrene-isoprene rubber (SBR), etc. are used as binders. Styrene rubber, acrylonitrile butadiene rubber, butadiene rubber, fluororubber, ethylene Rubber materials such as ethylene-propylene-diene copolymers can be used. These rubber materials may be used in combination with the water-soluble polymers described above. It has a high elasticity and is therefore resistant to expansion and contraction of the active material during charging and discharging, and bending of the electrode. While it is possible to obtain a stress-resistant and highly reliable electrode, it also has a hydrophobic group and is difficult to dissolve in water. In such cases, the particles are dispersed in an aqueous solution without dissolving in water. Therefore, a composition containing a solvent used to form the active material layer (also called an electrode mixture composition) is applied. In this case, it is difficult to increase the viscosity to a level suitable for the application of the viscosity adjustment function. The use of highly water-soluble polymers, such as polysaccharides, is expected to have the effect of moderately increasing the viscosity of the solution. In addition, it disperses uniformly with the rubber material, making it possible to create a highly uniform and good electrode, for example, An electrode with high uniformity in electrode resistance can be obtained.

[0200] Alternatively, PVDF, polystyrene, polymethyl acrylate, polymethacrylate, etc. may be used as a binder. Methyl acrylate (Polymethyl methacrylate (PMMA)), sodium polyacrylate, poly Polyvinyl alcohol (PVA), polyethylene oxide (PEO), polypropylene oxide Sid, polyimide, polyvinyl chloride, polytetrafluoroethylene, polyethylene, poly Propylene, polyisobutylene, polyethylene terephthalate, nylon, polyacrylonitrile Nitrile (PAN), Ethylene Propylene Diene Polymer, Polyvinyl Acetate, Nitrocel Materials such as loin can be used.

[0201] Two or more of the above binders may be used in combination.

[0202] The content of the binder relative to the total amount of the active material layer is preferably 1 wt% or more and 10 wt% or less, The content is more preferably from 2 wt% to 5 wt%.

[0203] <Separator> In the power storage device of one embodiment of the present invention, polyphenylene sulfide (PPS) or cellulose The separator may have a single layer structure or a laminated structure. For example, a separator containing cellulose fibers and another separator may be laminated. It's okay to have one.

[0204] Materials that can be used for the separator include polyphenylene sulfide and cellulose. In addition to fibers, polypropylene sulfide, fluoropolymers, cellulose, paper, nonwoven fabrics , glass fiber, ceramics, or nylon (polyamide), vinylon (polyvinyl) Alcohol-based fibers), polyester, acrylic, polyolefin, polyurethane, etc. One or more types selected from synthetic fibers and the like can be used.

[0205] <Exterior body> The surface of the exterior body 509 that comes into contact with the electrolyte 508, i.e., the inner surface, has a significant reaction with the electrolyte 508. It is preferable that the moisture content of the electricity storage device 500 does not increase. If water gets mixed in, a reaction may occur between the components of the electrolyte 508 and water. 09 preferably has low moisture permeability.

[0206] The exterior body 509 is made of, for example, polyethylene, polypropylene, polycarbonate, iono Flexible materials such as aluminum, stainless steel, copper, and nickel are applied to a film made of acrylic or polyamide. A thin metal film having excellent heat resistance is provided on the thin metal film, and a polyamide resin is further provided on the outer surface of the exterior body. A three-layer film having an insulating synthetic resin film such as a polyester resin may be used. This three-layer structure prevents electrolyte and gas permeation and provides insulation. The outer casing can be folded inward and stacked, or two By stacking the two exterior bodies with the inner surfaces facing each other and applying heat, the inner material The two exterior bodies can be fused together to form a sealed structure.

[0207] If the sealing portion is the part where the exterior body is fused or otherwise formed into a sealed structure, the exterior body can be folded inward. When the package is folded and stacked, a sealing portion is formed at a location other than the fold, and the first region of the exterior body and The first area and the overlapping second area are fused together. When the adhesive is melted, a sealing portion is formed around the entire periphery by a method such as heat sealing.

[0208] The power storage device 500 has a flexible structure by using a flexible exterior body 509. If the flexible structure is adopted, at least a part of the flexible portion can be The power storage device 500 can be mounted on an electronic device having a It is also possible to do so.

[0209] Note that in one embodiment of the present invention, a graphene compound is used for each component of a power storage device. As will be described later, graphene compounds can be modified to have a wide range of structures and properties. Therefore, it is possible to obtain desirable properties depending on the component to which the graphene compound is to be applied. In addition, graphene compounds have high mechanical strength, so The compound can also be applied to each member constituting a flexible electricity storage device. The laphene compound will be described.

[0210] Graphene is a single atomic layer of carbon atoms with π bonds between the carbon atoms. When two to 100 layers of graphene are stacked, they are sometimes called multi-graphene. Graphene and multi-graphene are, for example, The length is 50 nm or more and 100 μm or less, or 800 nm or more and 50 μm or less.

[0211] In this specification and the like, a compound having graphene or multigraphene as a basic skeleton Graphene Compound Graphene compounds include graphene and multigraphene.

[0212] The graphene compound will be described in detail below.

[0213] Graphene compounds, for example, are compounds in which graphene or multigraphene has atoms other than carbon, or or a compound modified with an atomic group having an atom other than carbon. Multi-graphene is modified with carbon-based atomic groups such as alkyl groups and alkylene groups. The atomic group modifying the graphene or multi-graphene may be a substituent. In this specification, modification means a group selected from the group consisting of a substituent, a functional group, a characteristic group, etc. , substitution reactions, addition reactions or other reactions to form graphene, multi-graphene, graphene phene compounds, or graphene oxide (described later), containing atoms other than carbon, This refers to the introduction of an atomic group containing carbon or an atomic group mainly composed of carbon.

[0214] The front and back surfaces of graphene may be modified with different atoms or atomic groups. In multi-graphene, each layer is modified with a different atom or atomic group. It may also be used.

[0215] An example of graphene modified with the above atoms or atomic groups is oxygen or oxygen-containing Examples of such graphene include graphene or multi-graphene modified with functional groups containing oxygen. Examples of functional groups include carbonyl groups such as epoxy groups and carboxyl groups, and hydroxyl groups. The graphene compound modified with oxygen or a functional group having oxygen is In this specification, graphene oxide refers to a multilayer It also includes graphene oxide.

[0216] As an example of modification of graphene oxide, silylation of graphene oxide will be explained. First, graphene oxide was placed in a container in a nitrogen atmosphere, and n-butylamine was added to the container. Add toluene (C4H9NH2) and keep at 60°C and stir for 1 hour. Then, alkyltrichlorosilane was further added as a silylating agent, and the mixture was stirred in a nitrogen atmosphere. The mixture is then stirred at 60°C for 5 hours. Next, toluene is added to the container and the mixture is filtered by suction to obtain a solid. The resulting powder is dispersed in ethanol and filtered with suction to obtain a solid powder. The resulting powder is dispersed in acetone, which is then filtered by suction to obtain a solid powder, and the liquid component is then removed. Vaporization yields silylated graphene oxide.

[0217] The modification is not limited to silylation, and the silylation is not limited to the above-mentioned method. It is not just the introduction of atoms or groups of atoms that can be used to modify the molecules, but also the introduction of multiple types of atoms or groups of atoms that can be used to modify the molecules. By introducing a specific atomic group into the graphene compound, The physical properties of graphene compounds can be changed. By applying desired modifications accordingly, desired properties can be intentionally expressed in graphene compounds. It can be done.

[0218] Next, an example of a method for producing graphene oxide will be described. Alternatively, multi-graphene can be obtained by oxidizing the graphene. Graphite oxide can be obtained by oxidizing graphite. Here, graphene oxide can be further modified with the above-mentioned atoms or atomic groups. You may do so.

[0219] The compound obtained by reducing graphene oxide is called RGO (Reduced Graphene Oxide). RGO is sometimes called graphene oxide. Not all of the oxygen atoms are removed, and some oxygen atoms or atomic groups containing oxygen atoms remain bonded to the carbon atoms. For example, RGO may contain carbonyl groups such as epoxy groups, carboxyl groups, or may have a functional group such as a hydroxyl group.

[0220] Graphene compounds are composed of multiple graphene compounds that overlap partially to form a single sheet. Such a graphene compound may be referred to as a graphene compound sheet. The graphene compound sheet has a thickness of, for example, 0.33 nm or more and 10 mm or less, Preferably, the graphene compound sheet has a region of greater than 0.34 nm and less than 10 μm. The group is an atom other than carbon, an atomic group containing atoms other than carbon, or a group containing mainly carbon such as an alkyl group. The graphene compound sheet may be modified with an atomic group such as Each of the several layers may be modified with a different atom or atomic group.

[0221] Graphene compounds are composed of not only six-membered rings made up of carbon but also five-membered rings made up of carbon and In this case, in the vicinity of the seven-membered ring or more, In this case, there may be an area through which lithium ions can pass.

[0222] Furthermore, for example, a plurality of graphene compounds may be gathered together to form a sheet shape.

[0223] The graphene compound has a planar shape, which allows for surface contact.

[0224] Graphene compounds can be highly conductive even when they are thin, and surface contact can cause the graphene compounds to It is possible to increase the contact area between objects or between the graphene compound and the active material. Therefore, even if the amount per volume is small, a conductive path can be formed efficiently.

[0225] On the other hand, graphene compounds can also be used as insulators. The sheet can be used as a sheet-like insulator. For example, graphene oxide is In some cases, the insulating properties are higher than those of non-oxidized graphene compounds. Modified graphene compounds can improve their insulating properties depending on the type of atomic group used to modify them. This may be possible.

[0226] Here, in this specification and the like, the graphene compound may have a graphene precursor. A graphene precursor is a substance used to produce graphene. The ene precursor may include, for example, the above-mentioned graphene oxide or graphite oxide. .

[0227] Note that graphene containing alkali metals and graphene containing elements other than carbon, such as oxygen, In this specification and the like, graphene compounds include graphene analogues. Laphene analogues are also included.

[0228] In addition, the graphene compound in this specification and the like has atoms, atomic groups, and their interlayer bonds. In addition, the graphene compound may have atoms, atomic groups, and their ions between layers. By having ions, the physical properties of graphene compounds, such as electrical conductivity and ionic conductivity, are improved. The interlayer distance may also increase.

[0229] Graphene compounds have excellent electrical properties, such as high conductivity, as well as high flexibility and high In addition, graphene may have excellent physical properties such as high mechanical strength. Depending on the type of modification, the compound may become an insulator by making the conductivity extremely low. In addition, the graphene compound has a planar shape. The graphene compound has low contact resistance. This allows for low surface contact.

[0230] This embodiment mode can be combined with other embodiment modes as appropriate.

[0231] (Embodiment 2) In this embodiment, electronic devices of one embodiment of the present invention will be described with reference to FIGS. do.

[0232] <Smartwatch configuration example 1> FIG. 14A is a perspective view of a wristwatch-type mobile information terminal (also called a smart watch) 700. The mobile information terminal 700 includes a housing 701, a display panel 702, a clasp 703, a band 705A, 705B, and operation buttons 711, 712.

[0233] A display panel 702 mounted on a housing 701 that also serves as a bezel has a rectangular display area. The display area is a curved surface. The display panel 702 is flexible. It is preferable that the display area be non-rectangular.

[0234] The band 705A and the band 705B are connected to the housing 701. The clasp 703 is The band 705A and the housing 701 are connected to each other by, for example, a pin at the connection portion. The band 705B and the housing 701, as well as the band 705, are connected so as to be movable. The same applies to the connection between A and the clasp 703.

[0235] 14B and 14C are perspective views of the band 705A and the power storage device 750, respectively. The band 705A includes a power storage device 750. The power storage device 750 may include, for example, The power storage device 750 can be used in the band 70. 5A, and a positive electrode lead 751 and a negative electrode lead 752 are each partially buried. The positive electrode lead 751 and the negative electrode lead 752 protrude from the lead 705A (see FIG. 14(B)). The cover 752 is electrically connected to the display panel 702. The surface of the power storage device 750 is The pins are covered with a body 753 (see FIG. 14(C)). Specifically, the positive electrode lead 751 and the display panel 702, and the negative electrode lead The band 705A and the display panel 702 are connected to each other. The bands 705A and 705B may be electrically connected via pins. In addition, the configuration of the connection portion of the housing 701 can be simplified.

[0236] The power storage device 750 has flexibility. Specifically, the outer casing 753 has a surface that is flexible. It is preferable that the surface has the unevenness formed by the embossing process described above. 750 preferably has a sliding surface similar to that of the power storage device 500 shown in FIG.

[0237] The band 705A can be manufactured by being integrally formed with the power storage device 750. For example, The electric storage device 750 is set in a mold corresponding to the outer shape of the band 705A, and the material of the band 705A is melted into the mold. The material is poured into a mold and hardened to produce the band 705A shown in FIG. 14(B). do.

[0238] When a rubber material is used as the material of the band 705A, the rubber is hardened by heat treatment. For example, if fluororubber is used as the rubber material, heat treatment at 170°C for 10 minutes will If silicone rubber is used as the rubber material, heat it at 150°C for 10 minutes. The power storage device of one embodiment of the present invention has high heat resistance, so the heat treatment is performed using a rubber material. This can suppress breakdown during heat treatment associated with integral formation of the battery and deterioration of charge / discharge characteristics.

[0239] The materials used for the band 705A include fluororubber, silicone rubber, and fluorosilicone. Examples include corn rubber and urethane rubber.

[0240] The power supply to the power storage device 750, including aging, is performed by the band 705A. In other words, the power storage device 500 described in the first embodiment It is preferable to perform a heat treatment before energizing the device 500. The heat treatment is performed at a temperature of 110°C or higher. At 90°C or less, the vulcanization time for the above rubber material is appropriate, for example, at 170°C. It is preferable to perform the heating process for 10 minutes. Deterioration of discharge characteristics can be suppressed.

[0241] Note that the portable information terminal 700 shown in FIG. 14A can have various functions. For example, the function to display various information (still images, videos, text images, etc.) in the display area, Panel function, calendar, date or time display function, various software ( It has a function to control processing by a program, a wireless communication function, and various controls using the wireless communication function. Functions for connecting to computer networks, transmitting various data using wireless communication functions, The function of receiving, reading out the program or data recorded on the recording medium and displaying it in the display area The function of displaying the image may be different from the image displayed on the screen.

[0242] In addition, a speaker, a sensor (force, displacement, position, velocity, acceleration, angular velocity) Degrees, rotation speed, distance, light, liquid, magnetism, temperature, chemical substances, sound, time, hardness, electric field, current, electricity Includes functions to measure pressure, power, radiation, flow rate, humidity, gradient, vibration, odor or infrared. The portable information terminal 700 may have a light-emitting element, a microphone, etc. The display panel 702 can be manufactured by using the above.

[0243] Although FIG. 14 shows an example in which the power storage device 750 is included in the band 705A, 50 may be included in band 705B. Band 705B may be the same as band 705A. Similar materials can be used.

[0244] The rubber material used for the band 705A is preferably highly resistant to chemicals. It is preferable that the reactivity with the electrolyte contained in the device 750 is low.

[0245] Even if the band 705A has excellent chemical resistance, cracks and peeling may occur in the band 705A. In this case, the user of the portable information terminal 700 may come into contact with the electrolyte leaked from the power storage device 750. If the portable information terminal 700 has a function for detecting electrolyte leakage, When a leak is detected, the user can stop operating the mobile information terminal 700 and remove it. Therefore, the portable information terminal 700 can be made highly secure.

[0246] <Smartwatch configuration example 2> FIG. 15(A) shows a band 735A having a different configuration from the band 705A shown in FIG. 14(B). The housing 731 connected to the band 735A is used to detect leakage of the electrolyte of the power storage device. The device is equipped with a leak detection circuit (not shown) that has the function of detecting a leak (see FIG. 14(A)). A perspective view of a portable information terminal 730 having a liquid leakage detection circuit is similar to that of the portable information terminal 700. .

[0247] The band 735A includes a power storage device 760. The power storage device 760 is embedded inside the band 735A. The positive electrode lead 751, the negative electrode lead 752, the terminal 761 and the terminal 762 are fitted into the band. The positive electrode lead 751 and the negative electrode lead 752 are protruding from the display panel 735A. Terminal 761 and terminal 762 are electrically connected to, for example, the above-mentioned leakage detection circuit. The circuit is electrically connected to the

[0248] FIG. 15B is a perspective view of the power storage device 760. For clarity, FIG. 15B is a perspective view of the power storage device 760. The power storage device 760 includes a terminal 761, a terminal 762, a wiring 77, and a 14C in that the power storage device 750 includes a terminal 7 and a wiring 772. The terminal 61 is electrically connected to the wiring 771. The terminal 762 is electrically connected to the wiring 772. can be.

[0249] For clarity, the wiring 771 and the wiring 772 are hatched differently in FIG. 15(B). 7, the wiring 771 and the wiring 772 can be formed from the same material to reduce the manufacturing cost. In addition, the terminal 761 and the wiring 771, and the terminal 762 and the wiring 772 are Although they are shown with the same hatching, the terminal 761 and the wiring 771, and the terminal 762 and The wirings 772 may be made of different materials.

[0250] The wiring 771 and the wiring 772 are laid on the surface of the exterior body 753 at a predetermined interval. When the electrolyte leaks onto the surface of the exterior body 753, the wiring 771 and the wiring The line 772 is electrically connected via the electrolyte, allowing the leakage detection circuit to detect leakage of the electrolyte.

[0251] In FIG. 15B, the wiring 771 and the wiring 772 are linearly arranged in the longitudinal direction of the power storage device 760. For example, as shown in FIG. 15(C), The wiring 771 and the wiring 772 may be provided in a comb-like shape so as to interdigitate with a gap therebetween.

[0252] FIG. 15C shows an example in which the wirings 771 and 772 are provided only on the upper surface of the exterior body 753. However, it is preferable that the insulating film 754 is provided over the entire surface of the exterior body 753 as shown in FIG. 16(A). Fig. 16(B) is a rear perspective view of power storage device 760 shown in Fig. 16(A).

[0253] When the wirings 771 and 772 are thin and have a small width, the flexibility of the power storage device 760 can be improved. For example, in the power storage device 760, the thickness of the wirings 771 and 772 is preferably 5 μm. It is preferable that the wiring 771 and the wiring 772 have a region of 500 μm or more and 500 μm or less. The small spacing between the electrodes and their small width allows even small amounts of electrolyte leakage to be detected. For example, in the power storage device 760, the distance between the wiring 771 and the wiring 772 is preferably 0.5 m. It is preferable that the power storage device 760 has a region of 20 mm or more and 20 mm or less. It is preferable that the width of 771 and 772 is 0.5 mm or more and 5 mm or less. In addition, if the area of ​​the wiring 771 and 772 on the surface of the exterior body 753 is too small, electrolyte leakage may occur. However, if the area is too large, the entire surface of the exterior body 753 cannot be covered. In the power storage device 760, the surface area of ​​the outer casing 753 may be reduced. The ratio of the surface area of ​​the wiring 771 and 772 excluding the side surfaces (surfaces in contact with the exterior body 753) to the It is preferably 5% or more and 50% or less.

[0254] The wirings 771 and 772 preferably contain a material that is highly ductile or malleable. By using a material with high ductility and malleability, the wiring 771 , 772 can be prevented from breaking. Materials with high ductility and malleability include gold, silver, platinum, iron, Metallic materials such as nickel, copper, aluminum, zinc, and tin, and alloys containing these metallic materials Examples include:

[0255] <How to detect a leak> An example of a method for detecting electrolyte leakage in the mobile information terminal 730 will be described below. FIG. 17(A) shows the portable information terminal 730 in a state where the electrolyte 736 has leaked. In FIG. 17(A), the lines containing arrows are The lines indicate the direction of transmission of wired or wireless signals. In addition, lines without arrows indicate wiring, and each element connected by the line is an electric electrically connected.

[0256] The portable information terminal 730 includes a liquid leakage detection circuit 732, a power supply 733, an ammeter 734, and a wiring 7 71 and wiring 772 (see FIG. 17(A)). The power supply 733 and the ammeter 734 are contained in the housing 731. The liquid detection circuit 732 may be included in the function circuit 732. 39. The functional circuit 739 includes the above-mentioned speaker, sensor, microphone, etc. The functional circuit 739 is contained in the housing 731 .

[0257] The wires 771 and 772 are electrically connected to the power supply 733, and there is a An arbitrary voltage is applied (see FIG. 17(A)). The power supply 733 is turned on and off depending on the leakage detection circuit. This is controlled by path 732.

[0258] FIG. 17(B) is a flowchart showing the process of detecting electrolyte leakage in the portable information terminal 730. For example, a method for detecting electrolyte leakage in the portable information terminal 730 is as follows. It has four steps:

[0259] If the electrolyte 736 of the electricity storage device 760 leaks, the electrolyte 736 adheres to the surface of the exterior body 753. (See S1 in FIG. 17(A) and FIG. 17(B)). The electrolyte attached to the surface of the exterior body 753 736 comes into contact with the wiring 771 and the wiring 772, A current flows (see S2 in FIG. 17B). The current is measured by an ammeter connected in parallel to the wiring 772. When the ammeter 734 detects the leakage, it outputs a detection signal to the leakage detection circuit 732 (see FIG. 17). (See (B) S3). The liquid leakage detection circuit 732 detects the liquid leakage from the display panel 702 or and / or the operation of the functional circuit 739 is stopped (see S4 in FIG. 17B).

[0260] In addition, although FIG. 17A shows an example in which the ammeter 734 is connected to the wiring 772, the ammeter 73 4 may be connected to the wiring 771. Also, a power supply 733 and an ammeter 734 may be connected to the leakage detection The leakage detection circuit 732 is electrically connected to the wiring 771 and 772. In this case, the leakage detection circuit 732 may be connected to the wirings 771 and 772. and a function of detecting the current flowing through the wirings 771 and 772. do.

[0261] This embodiment mode can be combined with other embodiment modes as appropriate.

[0262] (Embodiment 3) In this embodiment, a flexible power storage device according to one embodiment of the present invention will be described with reference to FIGS. 25. The power storage device of one embodiment of the present invention may have a curved shape. Furthermore, the power storage device of one embodiment of the present invention has flexibility and can be used in both a curved and an uncurved state. The device may be usable in both states.

[0263] <Configuration example 1> FIG. 18(A) shows a perspective view of the secondary battery 200, and FIG. 18(B) shows a top view of the secondary battery 200. Shows.

[0264] FIG. 19(A) shows a cross-sectional view taken along the dashed line C1-C2 in FIG. 18(B). 18(B) shows a cross-sectional view taken along the dashed line C3-C4 in FIG. 18(B). 19(B), some of the components are selectively shown for clarity.

[0265] The secondary battery 200 includes a positive electrode 211, a negative electrode 215, and a separator 203. The battery 200 further includes a positive electrode lead 221 , a negative electrode lead 225 , and an outer casing 207 .

[0266] The positive electrode 211 and the negative electrode 215 each have a current collector and an active material layer. The negative electrodes 215 are arranged so that the active material layers face each other with the separator 203 interposed therebetween. There are.

[0267] The electrodes (positive electrode 211 and negative electrode 215) of the secondary battery 200 are located on the inner diameter side of the curve. It is preferable that the one positioned on the outer diameter side is longer in the direction of curvature than the one positioned on the outer diameter side. With this configuration, when the secondary battery 200 is bent at a certain curvature, the positive electrode 211 and the negative electrode 212 are In other words, all of the positive electrode active material layers of the positive electrode 211 can be aligned. All of the regions can be disposed facing the negative electrode active material layer of the negative electrode 215. Therefore, the positive electrode active material contained in the positive electrode 211 can be efficiently utilized in the battery reaction. Therefore, the capacity per volume of the secondary battery 200 can be increased. This is particularly effective when the curvature of the secondary battery 200 is fixed when the battery 200 is in use.

[0268] The positive electrode lead 221 is electrically connected to the plurality of positive electrodes 211. The negative electrode lead 225 is , and are electrically connected to the plurality of negative electrodes 215. The positive electrode lead 221 and the negative electrode lead 225 Each of the semiconductor devices has a sealing layer 220 .

[0269] The exterior body 207 includes a plurality of positive electrodes 211, a plurality of negative electrodes 215, and a plurality of separators 203. The secondary battery 200 has an electrolyte (not shown) in the area covered by the exterior body 207. The secondary battery 200 is sealed by gluing three sides of the exterior body 207 together.

[0270] 19(A) and 19(B), a plurality of rectangular separators 203 are used, and a positive electrode 211 In the example shown, one separator 203 is disposed between the positive electrode 215 and the negative electrode 215, but One embodiment is not limited to this. A single sheet-shaped separator may be folded zigzag (accordion-shaped). or by winding it, the separator is positioned between the positive and negative electrodes. You can do this.

[0271] For example, the secondary battery 200 shown in FIGS. 21(A), 21(B), 21(C), and 21(D) When this manufacturing method is used, the dashed line C1-C in FIG. A cross-sectional view of the two sections is shown in FIG.

[0272] First, the negative electrode 215 is placed on the separator 203 (FIG. 21(A)). The negative electrode active material layer of 215 is disposed so as to overlap with the separator 203 .

[0273] Next, the separator 203 is folded and placed on the negative electrode 215. Then, the positive electrode 211 is placed on the separator 203 (FIG. 21(B)). The positive electrode active material layer of the separator 201 is disposed so as to overlap the separator 203 and the negative electrode active material layer. When an electrode having an active material layer formed on one side of a current collector is used, the positive electrode 211 The positive electrode active material layer and the negative electrode active material layer of the negative electrode 215 are arranged opposite to each other with the separator 203 interposed therebetween. Place.

[0274] When the separator 203 is made of a material that can be heat-sealed, such as polypropylene, The overlapping area of ​​the electrodes 203 is thermally welded together, and then the next electrode is placed on top of it. Specifically, the electrode can be prevented from shifting during the process. In the region where the separators 203 overlap each other, for example, the region 203 in FIG. It is preferable to heat-weld the area indicated by a.

[0275] By repeating this process, the positive electrode 202 is formed with the separator 203 sandwiched between them as shown in FIG. 21(C). 211 and anode 215 can be stacked.

[0276] The separator 203 is repeatedly folded in advance, and a plurality of negative electrodes 215 and a plurality of negative electrodes 215 are attached to the separator 203. The positive electrodes 211 may be arranged so as to be sandwiched alternately.

[0277] Next, as shown in FIG. 21(C), a plurality of positive electrodes 211 and a plurality of negative electrodes are separated by a separator 203. Covers 215.

[0278] Furthermore, as shown in FIG. 21(D), in the region where the separators 203 overlap each other, for example, By thermally welding the region 203b shown in FIG. 21(D), a plurality of positive electrodes 211 and a plurality of negative electrodes 2 15 is covered with a separator 203 and bound.

[0279] The plurality of positive electrodes 211, the plurality of negative electrodes 215, and the separator 203 are bound together using a binding material. May be bundled.

[0280] In this process, the positive electrode 211 and the negative electrode 215 are stacked, and the separator 203 is In the separator 203, the region sandwiched between the plurality of positive electrodes 211 and the plurality of negative electrodes 215 and a region disposed so as to cover the plurality of positive electrodes 211 and the plurality of negative electrodes 215.

[0281] In other words, the separator 203 of the secondary battery 200 shown in FIGS. 20 and 21(D) is , is a single separator that is partially folded. A plurality of positive electrodes 211 and a plurality of negative electrodes 215 are sandwiched between the positive electrodes 211 and the negative electrodes 215.

[0282] <Configuration example 2> FIG. 22(A) shows a perspective view of the secondary battery 250, and FIG. 22(B) shows a top view of the secondary battery 250. 22(C1) shows a cross-sectional view of the first electrode assembly 230, and FIG. 22(C2) shows a cross-sectional view of the first electrode assembly 230. ) shows a cross-sectional view of the second electrode assembly 231.

[0283] The secondary battery 250 includes a first electrode assembly 230, a second electrode assembly 231, and a separator. The secondary battery 250 further includes a positive electrode lead 221, a negative electrode lead 225, and and an exterior body 207.

[0284] As shown in FIG. 22(C1), the first electrode assembly 230 includes a positive electrode 211a, a separator 211b, and a 03, a negative electrode 215a, a separator 203, and a positive electrode 211a are laminated in this order. The positive electrode 211a and the negative electrode 215a each have an active material layer on both sides of a current collector. do.

[0285] As shown in FIG. 22(C2), the second electrode assembly 231 includes a negative electrode 215a, a separator 215b, and a 03, a positive electrode 211a, a separator 203, and a negative electrode 215a are laminated in this order. The positive electrode 211a and the negative electrode 215a each have an active material layer on both sides of a current collector. do.

[0286] That is, in the first electrode assembly 230 and the second electrode assembly 231, the positive electrode and the negative electrode are The active material layers are arranged so as to face each other with the separator 203 interposed therebetween.

[0287] The positive electrode lead 221 is electrically connected to the plurality of positive electrodes 211. The negative electrode lead 225 is , and are electrically connected to the plurality of negative electrodes 215. The positive electrode lead 221 and the negative electrode lead 225 Each of the semiconductor devices has a sealing layer 220 .

[0288] FIG. 23 shows an example of a cross-sectional view taken along the dashed line D1-D2 in FIG. 22(B). In order to clarify the diagram, only some of the components are shown in FIG.

[0289] As shown in FIG. 23, the secondary battery 250 includes a plurality of first electrode assemblies 230 and a plurality of second The electrode assembly 231 is covered with a wound separator 203.

[0290] The exterior body 207 includes a plurality of first electrode assemblies 230, a plurality of second electrode assemblies 231, and The secondary battery 200 contains an electrolyte (see FIG. The secondary battery 200 is sealed by adhering three sides of the exterior body 207. are.

[0291] For example, the secondary battery 250 shown in FIGS. 24(A), 24(B), 24(C), and 24(D) The method for producing the above is shown below.

[0292] First, the first electrode assembly 230 is placed on the separator 203 (FIG. 24(A)).

[0293] Next, the separator 203 is folded and placed on the first electrode assembly 230. Next, two sets of first electrode plates are placed above and below the first electrode assembly 230 with separators 203 interposed therebetween. The two electrode assemblies 231 are stacked (FIG. 24(B)).

[0294] Next, the separator 203 is wound around the two sets of second electrode assemblies 231. Furthermore, two sets of first electrode assemblies 231 are disposed above and below the two sets of second electrode assemblies 231 via separators 203. The electrode assemblies 230 are then stacked (FIG. 24(C)).

[0295] Next, the separator 203 is wound around the two first electrode assemblies 230 so as to cover them (see FIG. 24(D)).

[0296] Through this process, a plurality of first electrode assemblies 230 and a plurality of second electrode assemblies 231 are stacked. To stack these electrode assemblies, they are arranged between spirally wound separators 203. It will be placed.

[0297] It is preferable that the outermost electrode does not have an active material layer on the outside.

[0298] In addition, in Figures 22(C1) and 22(C2), the electrode assembly consists of three electrodes and two separators. However, one embodiment of the present invention is not limited to this. By increasing the number of electrodes, the capacity of the secondary battery 250 can be increased. It is also possible to use a configuration having two electrodes and one separator. When the number of electrodes is small, the secondary battery can be made more resistant to bending. The secondary battery 250 has three sets of first electrode assemblies 230 and two sets of second electrode assemblies 231. However, one aspect of the present invention is not limited to this. By increasing the number of electrode assemblies, the capacity of the secondary battery 250 can be further improved. Also, a configuration having fewer electrode assemblies may be adopted. In this case, the secondary battery can be made more resistant to bending.

[0299] FIG. 25 shows another example of a cross-sectional view taken along the dashed dotted line D1-D2 in FIG. 22(B). As shown in FIG. 25, the separator 203 is folded in an accordion shape to form the first electrode assembly. A separator 203 may be disposed between 230 and the second electrode assembly 231 .

[0300] This embodiment mode can be combined with other embodiment modes as appropriate.

[0301] (Fourth embodiment) In this embodiment, an example of use of a power storage device of one embodiment of the present invention will be described with reference to FIGS. 26 to 30. I will explain.

[0302] The power storage device of one embodiment of the present invention can be used in electronic devices and lighting devices, for example. The power storage device of one embodiment has excellent charge and discharge characteristics. It can be used for a long time with one charge. In addition, the decrease in capacity due to charge / discharge cycles is suppressed. Therefore, even if the battery is repeatedly charged, the usable time is not likely to become shorter. The power storage device of one embodiment exhibits excellent charge and discharge characteristics over a wide temperature range including a high-temperature environment, and can be used for a long time. High reliability and safety can improve the safety and reliability of electronic devices and lighting equipment. do.

[0303] Examples of electronic devices include television sets (also known as televisions or television receivers). (c), computer monitors, digital cameras, digital video cameras, digital Photo frames, mobile phones (also called mobile phones or mobile phone devices), portable game consoles, mobile phones Examples include portable information terminals, audio playback devices, and large game machines such as pachinko machines.

[0304] Since the power storage device of one embodiment of the present invention has flexibility, the power storage device itself or the power storage device Installing electronic equipment or lighting equipment using the device on the interior or exterior walls of a house or building, or on the interior or exterior walls of a vehicle It is also possible to incorporate it along the curved surface of the interior or exterior of the vehicle.

[0305] FIG. 26A shows an example of a mobile phone. The mobile phone 7400 has a housing 7401. In addition to the display unit 7402 incorporated in the The mobile phone 7400 is equipped with a speaker 7405, a microphone 7406, and the like. It has device 7407.

[0306] FIG. 26B shows the mobile phone 7400 in a bent state. When the entire device is deformed by an external force and curved, the power storage device installed inside The power storage device 7407 is also curved. The power storage device 7407 is a thin power storage device. The power storage device 7407 in a curved state is fixed as shown in FIG. .

[0307] FIG. 26(D) shows an example of a bangle-type display device. The portable display device 7100 includes: The device includes a housing 7101, a display portion 7102, operation buttons 7103, and a power storage device 7104. FIG. 26E shows the bent state of the power storage device 7104.

[0308] FIG. 26(F) shows an example of a wristwatch-type portable information terminal. The portable information terminal 7200 is , a housing 7201, a display unit 7202, a band 7203, a buckle 7204, and an operation button 72 05, input / output terminal 7206, etc.

[0309] The portable information terminal 7200 is capable of carrying out mobile phone calls, e-mails, viewing and creating documents, playing music, and internet access. - It can run various applications such as internet communication and computer games. do.

[0310] The display surface of the display unit 7202 is curved, and the display is performed along the curved display surface. The display portion 7202 is provided with a touch sensor, and can be touched with a finger or a stylus. For example, the icon 72 displayed on the display unit 7202 can be operated by touching it. You can launch the application by touching 07.

[0311] The operation button 7205 is used to set the time, turn the power on and off, and turn wireless communication on and off. It has various functions such as operation, silent mode activation and deactivation, power saving mode activation and deactivation, etc. For example, an operating system installed in the portable information terminal 7200 can The function of the operation button 7205 can also be freely set using the stem.

[0312] In addition, the mobile information terminal 7200 is capable of performing standardized short-range wireless communication. For example, by communicating with a wireless headset, hands-free operation is possible. You can also make calls.

[0313] The portable information terminal 7200 also has an input / output terminal 7206, and a connector for connecting to other information terminals. Data can be exchanged directly via the input / output terminal 7206. The charging operation can be performed by wireless power supply without going through the input / output terminal 7206. It is also possible.

[0314] The display portion 7202 of the portable information terminal 7200 includes the power storage device of one embodiment of the present invention. For example, the power storage device 7104 shown in FIG. 26E may be curved and placed inside the housing 7201. Alternatively, it can be incorporated into the band 7203 in a bendable state.

[0315] FIG. 27A shows an example of a wrist-worn activity meter. The activity meter 7250 has a housing 7251, a band 7203, a buckle 7204, etc. It is equipped with a wireless communication device, a pulse sensor, an acceleration sensor, a temperature sensor, etc. The pulse sensor and acceleration sensor acquire information such as the wearer's pulse rate and activity level, and wirelessly The communication device has a function to transmit the information to an external mobile information terminal. The 250 has the functions of measuring the wearer's calorie consumption and intake, counting steps, The activity meter 7250 may have a function for measuring a sleep state. The information acquired by the above function may be displayed.

[0316] The activity meter 7250 includes the power storage device of one embodiment of the present invention. The power storage device 7104 shown in FIG. 71 is curved inside the housing 7201 or is attached to a band 7203. It can be incorporated into the interior of the device in a bendable state.

[0317] FIG. 27B shows an example of a wristband-type display device. The display device 7300 includes a display unit 7 304 and includes the power storage device of one embodiment of the present invention. The display unit 7304 may be provided with a touch sensor, and may function as a portable information terminal. It is also possible.

[0318] The display surface of the display unit 7304 is curved, and images can be displayed along the curved display surface. The display device 7300 can also communicate with the display device 7300 by short-distance wireless communication according to a communication standard. The situation can be changed.

[0319] The display device 7300 is also equipped with an input / output terminal, and can be directly connected to other information terminals via a connector. It is also possible to charge the device via the input / output terminals. The charging operation may be performed by wireless power supply without using the input / output terminals.

[0320] FIG. 27C shows an example of a glasses-type display device. The display device 7350 is a lens-type display device. 7351, a frame 7352, etc. Also, the inside or the frame A projection unit (not shown) that contacts the lens 7352 and projects an image or video onto the lens 7351. The display device 7350 displays an image 7351A on the entire lens 7351 so that the wearer can visually recognize the image 7351A. Or, the lens 7351 may have a function of projecting the image 7351B onto a part of the lens 7351. It has the function of displaying in a direction that can be seen by the wearer.

[0321] The display device 7350 includes the power storage device of one embodiment of the present invention. The figure shows an enlarged view of the tip 7355 of the rubber 7352. The tip 7355 is made of fluorine rubber, silicone, The tip portion 7355 can be formed of a rubber material such as rubber. A positive electrode lead 7361 and a negative electrode lead 7362 are attached to the distal end 735. 5. The positive lead 7361 and the negative lead 7362 are attached to the frame 735. 2 and is electrically connected to the wiring connected to the projection unit, etc. The power storage device 7360 and the power storage device 55 can be integrally formed as described in Embodiment 2. This can be done.

[0322] The tip portion 7355 and the power storage device 7360 are flexible. It can be worn to fit snugly to the user's head shape.

[0323] Figures 28(A) and 28(B) show an example of a foldable tablet terminal. The tablet terminal 9600 shown in FIG. 8(A) and FIG. 28(B) includes a pair of housings 9630 and a A movable part 9640 connecting the pair of housings 9630, a display part 9631a, a display part 9631b, a display Display mode selector switch 9626, power switch 9627, power saving mode selector switch 28(A) shows the tab 9625, the fastener 9629, and the operation switch 9628. 28(A) shows the tablet terminal 9600 in an open state, and FIG. 28(B) shows the tablet terminal 9600 in an open state. is shown in the closed state.

[0324] The tablet terminal 9600 also includes a power storage unit 9635 inside the housing 9630. The electric body 9635 passes through the movable part 9640 and moves from one housing 9630 to the other housing 9630. It is set up across.

[0325] A part of the display unit 9631a can be used as a touch panel area 9632a. By touching the operation keys 9638, data can be input. In 1a, for example, half of the area has a display function only, and the other half Although the display area 96 has a touch panel function, the display area 96 is not limited to this configuration. The entire area of ​​the display unit 9 may have a touch panel function. The entire surface of 631a is used as a touch panel by displaying keyboard buttons, and the display part 9631b is used as a touch panel. It can be used as a display screen.

[0326] In addition, in the display unit 9631b, as in the display unit 9631a, a part of the display unit 9631b The area 9632b of the touch panel can be used as the keyboard of the touch panel. By touching the area where the display switch button 9639 is displayed with your finger or a stylus, A keyboard can be displayed on the display portion 9631b.

[0327] In addition, touch panel area 9632a and touch panel area 9632b can be touched simultaneously. You can also input characters using the touchpad.

[0328] A display mode changeover switch 9626 changes the display orientation between portrait and landscape. You can select between black and white and color display. The touch 9625 detects when in use by the light sensor built into the tablet terminal 9600. The display brightness can be optimized according to the amount of external light. In addition to optical sensors, other sensors such as gyros and acceleration sensors that detect tilt are also available. The device may be built-in.

[0329] FIG. 28A shows an example in which the display areas of the display portions 9631a and 9631b are the same. However, there is no particular limitation, and the size of one display part may be different from the size of the other display part. For example, one may display a higher resolution image than the other. The display panel may also be a display panel.

[0330] FIG. 28(B) shows the tablet terminal in a closed state, and the tablet terminal includes a housing 9630 and a solar cell 96 33, a charge / discharge control circuit 9634 including a DC / DC converter 9636. The power storage device of one embodiment of the present invention is used as the body 9635.

[0331] In addition, since the tablet terminal 9600 can be folded in two, when not in use, the pair of housings 9630 By folding, the display portion 9631a Since the display unit 9631b can be protected, the durability of the tablet terminal 9600 can be improved. Furthermore, the power storage unit 9635 using the power storage unit of one embodiment of the present invention has flexibility and can be bent. The charge / discharge capacity is not easily reduced even after repeated stretching. Therefore, it is a highly reliable tablet type. The device can be provided.

[0332] In addition, the tablet terminals shown in Figs. 28(A) and 28(B) can store various information. Functions for displaying information (still images, videos, text images, etc.) on the display, calendar, date, or Function to display the time etc. on the display, touch input operation or editing of the information displayed on the display Touch input function, function to control processing by various software (programs), etc. It can have.

[0333] The solar cell 9633 attached to the surface of the tablet terminal supplies power to the touch panel, The solar cell 9633 can be supplied to a display unit, a video signal processor, or the like. The structure can be provided on one or both sides of the power storage unit 9630, and can efficiently charge the power storage unit 9635. The power storage unit 9635 is preferably made of a lithium-ion The use of a battery has the advantage of enabling miniaturization.

[0334] The configuration and operation of the charge / discharge control circuit 9634 shown in FIG. 28(B) will be described with reference to FIG. ) is a block diagram and will be explained. In FIG. 28(C), a solar cell 9633, a power storage unit 9635 , DC-DC converter 9636, converter 9637, switches SW1 to SW3, display The figure shows a part 9631, a storage battery 9635, a DC-DC converter 9636, and a converter. 28B. This corresponds to 4.

[0335] First, an example of operation when power is generated by the solar cell 9633 using external light will be described. The power generated by the solar cell is converted into a voltage to charge the storage battery 9635. The converter 9636 increases or decreases the voltage. When power is used from the battery 9633, the switch SW1 is turned on, and the converter 963 7, the voltage is increased or decreased to the voltage required for the display unit 9631. When not displaying in 1, turn switch SW1 off and switch SW2 on. The power storage unit 9635 may be charged.

[0336] The solar cell 9633 is shown as an example of a power generating means, but is not particularly limited thereto. Storage by other power generation means such as piezoelectric elements and thermoelectric conversion elements (Peltier elements) For example, the power supply 9635 may be configured to transmit and receive power wirelessly (contactlessly). It is also possible to combine it with a contactless power transmission module that charges the battery, or other charging means. You may do so.

[0337] Another example of electronic equipment is shown in FIG. 29. In FIG. 29, a display device 8000 is a display device according to one embodiment of the present invention. 8 is an example of an electronic device using a power storage device 8004 according to an embodiment. 8000 corresponds to a display device for receiving TV broadcasts, and includes a housing 8001, a display unit 8002, and a speaker unit. The power storage device 8004 according to one embodiment of the present invention includes a housing 8003, a power storage device 8004, and the like. The display device 8000 is provided inside a body 8001. The display device 8000 receives power from a commercial power source. Alternatively, the power stored in the power storage device 8004 can be used. Even when power cannot be supplied from a commercial power source due to a power outage or the like, the present invention The power storage device 8004 can be used as an uninterruptible power supply, thereby enabling the use of the display device 8000. do.

[0338] The display unit 8002 includes a liquid crystal display device, an emitting device having a light emitting element such as an organic EL element in each pixel, and Device, electrophoretic display device, DMD (Digital Micromirror Device) ce), PDP (Plasma Display Panel), FED (Field A semiconductor display device such as a reflective LED (emission display) can be used.

[0339] In addition to TV broadcast reception, display devices are also used for personal computers and advertising displays. , including all display devices for displaying information.

[0340] In FIG. 29, a stationary lighting device 8100 includes a power storage device 81 according to one embodiment of the present invention. 8101, a housing 8102, a light source 8103, and a light source 8104. 29, the power storage device 8103 is mounted in a housing 81. 8101 and a light source 8102 are installed inside a ceiling 8104. However, the power storage device 8103 may be provided inside the housing 8101. The device 8100 can receive power from a commercial power source or store power in a power storage device 8103. Therefore, if the power supply from the commercial power source is interrupted due to a power outage, etc., Even when power cannot be received, the power storage device 8103 of one embodiment of the present invention can be used as an uninterruptible power supply. This allows the lighting device 8100 to be used.

[0341] 29 shows an example of a lighting device 8100 that is installed on a ceiling 8104. However, in the power storage device of one embodiment of the present invention, the side wall 8105, the floor 8106, and the like are not included in the ceiling 8104. 106, it can be used for a fixed lighting device provided in a window 8107, etc., or it can be used for a tabletop lighting device. It can also be used in lighting devices of this type.

[0342] The light source 8102 may be an artificial light source that artificially obtains light using electricity. Specifically, incandescent lamps, fluorescent lamps and other discharge lamps, and light-emitting devices such as LEDs and organic EL elements The element is an example of the artificial light source.

[0343] In FIG. 29, an air conditioner having an indoor unit 8200 and an outdoor unit 8204 is 8 is an example of an electronic device including a power storage device 8203 of one embodiment of the present invention. The device 8200 includes a housing 8201, an air outlet 8202, a power storage device 8203, and the like. 8 illustrates an example in which the power storage device 8203 is provided in the indoor unit 8200. The device 8203 may be provided in an outdoor unit 8204. Alternatively, the indoor unit 8200 and the outdoor unit The power storage device 8203 may be provided in both the power supply and the power source 8204. The power storage device 8203 can receive power from a commercial power source or can use the power stored in the power storage device 8203. In particular, both the indoor unit 8200 and the outdoor unit 8204 are provided with a power storage device 82 If 03 is installed, when power cannot be supplied from the commercial power source due to a power outage, etc. In addition, by using the power storage device 8203 of one embodiment of the present invention as an uninterruptible power supply, The conditioner can be used.

[0344] In Figure 29, a separate type air conditioner consisting of an indoor unit and an outdoor unit is shown. As an example, it is an all-in-one air conditioner that has the functions of both the indoor unit and the outdoor unit in a single housing. The power storage device according to one embodiment of the present invention can also be used in the conditioner.

[0345] In FIG. 29, an electric refrigerator-freezer 8300 includes a power storage device 8304 of one embodiment of the present invention. Specifically, an electric refrigerator-freezer 8300 includes a housing 8301, a refrigerator It has a storage compartment door 8302, a freezer compartment door 8303, a power storage device 8304, and the like. An electric device 8304 is provided inside the housing 8301. The electric refrigerator-freezer 8300 includes: The power can be supplied from a commercial power source, or the power stored in the power storage device 8304 can be used. Therefore, when power cannot be supplied from the commercial power source due to a power outage, etc. However, by using the power storage device 8304 of one embodiment of the present invention as an uninterruptible power supply, It will be possible to use the 8300-capacity refrigerator.

[0346] In addition, electronic devices such as microwave ovens and electric rice cookers generate high amounts of electricity for a short period of time. Therefore, it is used as an auxiliary power source to supplement the power that cannot be supplied by commercial power sources. By using a power storage device according to one embodiment of the present invention, it is possible to reduce the breaker voltage of a commercial power source when using an electronic device. It can prevent the car from falling.

[0347] In addition, during times when electronic devices are not in use, especially when the total amount of power that can be supplied by the commercial power supplier is low, During times when the percentage of electricity actually used (called the electricity usage rate) is low, By storing power in the device, it is possible to prevent power usage rates from increasing outside of the above time periods. For example, in the case of the electric refrigerator-freezer 8300, when the temperature is low and the refrigerator compartment door 830 2. During the night when the freezer door 8303 is not opened or closed, the power storage device 8304 stores power. Then, as the temperature rises, the refrigerator door 8302 and the freezer door 8303 are opened and closed. By using the power storage device 8304 as an auxiliary power source during the daytime, the daytime power usage rate can be kept low.

[0348] The power storage device of one embodiment of the present invention can also be mounted on a vehicle.

[0349] When a power storage device is installed in a vehicle, it can be used as a hybrid vehicle (HEV), electric vehicle (EV), or power storage device. This will enable the realization of next-generation clean energy vehicles such as plug-in hybrid vehicles (PHEVs). .

[0350] 30A and 30B illustrate examples of vehicles using the power storage device of one embodiment of the present invention. The automobile 8400 shown in FIG. 30(A) uses an electric motor as a power source for running. It is an electric vehicle. Or, it is a vehicle that can select an electric motor and an engine as a power source for driving. By using one embodiment of the present invention, A vehicle with a long cruising distance can be realized. In addition, the automobile 8400 has a power storage device. The energy storage device not only drives the electric motor, but also powers the headlights 8401 and interior lights. (not shown) can be powered.

[0351] In addition, the power storage device may be used for displaying the speedometer, tachometer, etc. of the automobile 8400. The power storage device can supply power to the navigation system of the automobile 8400. The present invention can provide power to semiconductor devices such as mobile terminals.

[0352] The automobile 8500 shown in FIG. 30B is a power storage device of the automobile 8500. It can be charged by receiving power from an external charging facility using a contactless power supply system or other methods. FIG. 30(B) shows the charging of electricity from a ground-mounted charging device 8021 to a storage battery mounted on an automobile 8500. The figure shows a state in which the charging device is being charged via a cable 8022. The power supply method and connector standards are applied according to the specified method such as CHAdeMO (registered trademark) or Combo. The charging device 8021 may be a charging station installed in a commercial facility. It can also be a household power source. For example, plug-in technology allows for external power supply. The power storage device 8024 mounted on the automobile 8500 can be charged by the above. This can be done by converting AC power to DC power via a conversion device such as an AC / DC converter. Cut.

[0353] Although not shown, a power receiving device is mounted on the vehicle and power is supplied contactlessly from a power transmitting device on the ground. In this case, a power transmission device is installed on the road or exterior wall. By incorporating this technology, charging can be carried out not only when the vehicle is stopped but also while the vehicle is moving. This method may be used to transmit and receive power between vehicles. A solar battery may be provided to charge the power storage device when the vehicle is stopped or running. The power can be supplied using an electromagnetic induction method or a magnetic field resonance method.

[0354] According to one embodiment of the present invention, the cycle characteristics of a power storage device can be improved, and the reliability can be improved. Furthermore, according to one embodiment of the present invention, the characteristics of the power storage device can be improved. Therefore, the size and weight of the power storage device itself can be reduced. This contributes to reducing the vehicle's weight, thereby improving the vehicle's cruising range. The power storage device can also be used as a power supply source for other purposes than vehicles. It is possible to avoid using commercial power during peak hours.

[0355] This embodiment mode can be combined with other embodiment modes as appropriate. [Example]

[0356] In this example, a power storage device according to one embodiment of the present invention was manufactured based on Embodiment 1. A cycle test was carried out at 25°C with the storage device.

[0357] <Sample preparation method> In this example, a power storage device 500 shown in FIG. 1A was manufactured. Reveal.

[0358] The samples to which one embodiment of the present invention is applied are Sample A1, Sample A2, Sample B1, Sample B2, and Sample C1. , Sample C2, Sample D1, Sample D2, Sample E1, Sample E2, Sample F1, Sample F2, Sample B3 The samples prepared for comparison were comparative sample a1 and comparative sample B4. There are two samples in total: sample a1 and sample a2.

[0359] Sample A1, Sample A2, Sample B1, Sample B2, Sample C1, Sample C2, Sample D1, Sample D2, Samples E1, E2, F1, F2, B3, and B4 contain lithium bicarbonate as the solute. Lithium(pentafluoroethanesulfonyl)amide (LiBETA) and lithium hexafluorophosphate Samples A1, A2, B1, B2, C1, C2, and D were used. 1. Sample D2, Sample E1, Sample E2, Sample F1, Sample F2, Sample B3 and Sample B4 are The concentrations of lithium fluorophosphate are different. In addition, comparative samples a1 and a2 contain lithium as a solute. Lithium bis(pentafluoroethanesulfonyl)amide (LiBETA) was used to No lithium phosphate was used.

[0360] Sample A1, Sample A2, Sample B1, Sample B2, Sample C1, Sample C2, Sample D1, Sample D2, Samples E1, E2, F1, F2, comparative samples a1 and a2 are separators. Cellulose fiber was used as the base material. Samples B3 and B4 were made of polyphenylene sulfide. PPS was used.

[0361] After the electricity storage device 500 was fabricated, Sample A2, Sample B2, Sample C2, Sample D2, and Sample E2, sample F2, sample B4 and comparative sample a2 were subjected to a heat treatment at 170° C. for 15 minutes. This heat treatment is intended to be integrated with the fluororubber described in the second embodiment. In addition, Sample A1, Sample B1, Sample C1, Sample D1, Sample E1, Sample F1, Sample B3 and Comparative sample a1 was not subjected to heat treatment.

[0362] The electrolyte, separator, and heat treatment conditions for each sample are shown in Table 1.

[0363] [Table 1]

[0364] A method for preparing the electrolyte will be described.

[0365] The electrolyte a used in the comparative samples a1 and a2 will now be described. A mixture of ethylene glycol (EC) and propylene carbonate (PC) in a volume ratio of 1:1 was added. Vinylene carbonate (VC) was mixed with lithium bis(pentafluoroethanesulfonyl) Electrolyte a was prepared by dissolving vinylene carbonate (V) in ethylenediamine diol (LiBETA). C) was dissolved in an amount of 1 wt% by weight in the electrolyte a. Fluoroethanesulfonyl)amide (LiBETA) is used in a molar concentration of 1 The amount was dissolved to give a concentration of 1000 mol / L.

[0366] The electrolyte A used in Samples A1 and A2 will be described. C) and propylene carbonate (PC) in a volume ratio of 1:1. carbonate (VC) and lithium bis(pentafluoroethanesulfonyl)amine. Electrolyte A was prepared by dissolving vinyl phosphate (LiBETA) and lithium hexafluorophosphate. The amount of VC dissolved in the electrolyte A was 1 wt %. Lithium bis(pentafluoroethanesulfonyl)amide (LiBETA) was used in electrolyte A. The amount of lithium hexafluorophosphate dissolved in the solution was 1 mol / L. A was dissolved in an amount that gave a weight ratio of 0.18 wt% to A.

[0367] The electrolyte B used in Samples B1, B2, B3, and B4 will now be described. Ethylene carbonate (EC) and propylene carbonate (PC) were mixed in a volume ratio of 1:1. Vinylene carbonate (VC) was added to the mixture, and lithium bis(pentafluoroethylene) Electrolyte by dissolving ethanesulfonylamide (LiBETA) and lithium hexafluorophosphate Vinylene carbonate (VC) was added at a weight ratio of 1 wt% to electrolyte B. The amount of lithium bis(pentafluoroethanesulfonyl)amide (LiBE TA) was dissolved in electrolyte B in an amount that gave a molar concentration of 1 mol / L. The lithium oxide was dissolved in the electrolyte B in an amount of 0.27 wt % in terms of weight ratio.

[0368] The electrolyte C used in Samples C1 and C2 will be described. C) and propylene carbonate (PC) in a volume ratio of 1:1. carbonate (VC) and lithium bis(pentafluoroethanesulfonyl)amine. Electrolyte C was prepared by dissolving vinyl phosphate (LiBETA) and lithium hexafluorophosphate. The amount of VC dissolved in the electrolyte C was 1 wt %. Lithium bis(pentafluoroethanesulfonyl)amide (LiBETA) in electrolyte C The amount of lithium hexafluorophosphate dissolved in the solution was 1 mol / L. The amount of 0.51 wt% of C was dissolved.

[0369] The electrolyte D used in Samples D1 and D2 will be described. C) and propylene carbonate (PC) in a volume ratio of 1:1. carbonate (VC) and lithium bis(pentafluoroethanesulfonyl)amine. Electrolyte D was prepared by dissolving vinyl phosphate (LiBETA) and lithium hexafluorophosphate. The amount of VC dissolved in the electrolyte D was 1 wt %. Lithium bis(pentafluoroethanesulfonyl)amide (LiBETA) is used in electrolyte D. The amount of lithium hexafluorophosphate dissolved in the solution was 1 mol / L. The amount of D was dissolved to give a weight ratio of 1.1 wt %.

[0370] The electrolyte E used in Samples E1 and E2 will be described. C) and propylene carbonate (PC) in a volume ratio of 1:1. carbonate (VC) and lithium bis(pentafluoroethanesulfonyl)amine. Electrolyte E was prepared by dissolving vinyl phosphate (LiBETA) and lithium hexafluorophosphate. The amount of VC dissolved in the electrolyte E was 1 wt %. Lithium bis(pentafluoroethanesulfonyl)amide (LiBETA) is used in the electrolyte E. The amount of lithium hexafluorophosphate dissolved in the solution was 1 mol / L. The amount of E was dissolved at a weight ratio of 2.0 wt %.

[0371] The electrolyte F used in samples F1 and F2 will be described. C) and propylene carbonate (PC) in a volume ratio of 1:1. carbonate (VC) and lithium bis(pentafluoroethanesulfonyl)amine. Electrolyte F was prepared by dissolving vinyl phosphate (LiBETA) and lithium hexafluorophosphate. The amount of VC dissolved in the electrolyte F was 1 wt %. Lithium bis(pentafluoroethanesulfonyl)amide (LiBETA) is used as the electrolyte F. The amount of lithium hexafluorophosphate dissolved in the solution was 1 mol / L. The amount of F dissolved was 3.0 wt % in terms of weight ratio.

[0372] Ethylene carbonate (EC) and propylene carbonate (PC) are mixed in a volume ratio of 1:1. The combined mixture is a lithium battery grade (product code number LBG- Vinylene carbonate (VC) was used. Terry grade (product code number LBG-84923) was used. Fluoroethanesulfonyl)amide (LiBETA) is a Manufactured by Liquids Technologies Inc. (Product Number KI-0016-H Lithium hexafluorophosphate (LiPF6) was used. Terry grade (product code number LBG-45860) was used.

[0373] The method for producing the negative electrode will be described. , Sample B2, Sample C1, Sample C2, Sample D1, Sample D2, Sample E1, Sample E2, Sample F1 , sample F2, sample B3, sample B4, comparative sample a1 and comparative sample a2 are all common. .

[0374] The negative electrode active material has a specific surface area of ​​6.3 m 2 / g, spherical natural graphite with an average particle size of 15 μm (Nippon Graphite The binder used was carboxymethyl cellulose (CGB-15 manufactured by Kogyo Co., Ltd.). The polymerization degree of the CMC-Na used was 60. 0 to 800, and the viscosity of the aqueous solution when used as a 1 wt% aqueous solution is 300 mPa·s or more. The values ​​were in the range of 500 mPa·s or less. The graphite:CMC-Na:SBR ratio was 97:1.5:1.5 (wt%).

[0375] First, the CMC-Na powder and the active material were mixed and kneaded in a kneader to obtain a first mixture.

[0376] Next, a small amount of water was added to the first mixture, and the mixture was kneaded to obtain a second mixture. The term "hard kneading" refers to kneading with high viscosity.

[0377] Next, water was further added and the mixture was kneaded using a kneader to obtain a third mixture.

[0378] Next, a 50 wt% aqueous dispersion of SBR was added and mixed using a mixer. The mixture was defoamed at 100° C. to obtain a slurry.

[0379] Next, the slurry was applied to the negative electrode current collector using a continuous coater. The coating speed was 0.75 m / min.

[0380] Next, the solvent of the slurry applied to the negative electrode current collector was evaporated using a drying oven. After treatment at 50°C for 120 seconds in an atmosphere, treatment at 80°C for 120 seconds was performed. Furthermore, the sample was treated at 100°C for 10 hours under a reduced pressure atmosphere (gauge pressure -100kPa). was carried out.

[0381] Through the above steps, a negative electrode active material layer was formed on one surface of the negative electrode current collector, thereby producing a negative electrode.

[0382] The method for producing the positive electrode will be described. The method for producing the positive electrode was the same for Samples A1, A2, and B1. , Sample B2, Sample C1, Sample C2, Sample D1, Sample D2, Sample E1, Sample E2, Sample F1 , sample F2, sample B3, sample B4, comparative sample a1 and comparative sample a2 are all common. .

[0383] The positive electrode active material is LiCoO2, and the binder is polyvinylidene fluoride (PVDF). The LiCoO2 has a specific surface area of ​​0.5 5m 2 LiCoO (C-5hV) manufactured by Nippon Chemical Industry Co., Ltd. with an average particle size of 6.3 μm was used. 2. The composition of PVDF and acetylene black is LiCoO2:acetylene black: The PVDF ratio was 95:3:2 (wt%).

[0384] In this specification, the average particle size refers to the cumulative 50% value (D50) on a volume basis. .

[0385] First, acetylene black and PVDF were mixed and kneaded in a kneader to obtain a third mixture. Ta.

[0386] Next, an active material was added to the third mixture to obtain a fourth mixture.

[0387] Next, N-methyl-2-pyrrolidone (NMP) as a solvent was added to the fourth mixture, and the mixture was kneaded. The mixture was kneaded using a mixer. A slurry was prepared by the above steps.

[0388] Next, the mixture was mixed in a large mixer.

[0389] Next, the slurry was applied to the positive electrode current collector using a continuous coater. An aluminum current collector (film thickness: 20 μm) was used, and the coating speed was 0.2 m / min.

[0390] Thereafter, the solvent of the slurry applied to the positive electrode current collector was evaporated using a drying furnace. The curing was carried out in an air atmosphere, and the curing was carried out at 70°C for 7.5 minutes, followed by 90°C for 7.5 minutes. The following processing was carried out.

[0391] Next, heat treatment was performed at 170°C for 10 hours under a reduced pressure atmosphere (gauge pressure -100kPa). Thereafter, the positive electrode active material layer was pressed by a roll press method to be compacted.

[0392] Through the above steps, a positive electrode active material layer was formed on one surface of the positive electrode current collector, thereby producing a positive electrode.

[0393] The average values ​​of the active material loading, film thickness, and density of the prepared positive electrode active material layer are shown in Table 2. The values ​​are shown in Table 3. Note that these values ​​shown in this specification are for each of the electrodes used in preparing the samples. When the current collector has active material layers on both sides, these values ​​are the average of the active material layers on one side. It corresponds to the average value of the amount of active material carried, the film thickness, and the density in the material layer.

[0394] The amount of support was calculated from the area of ​​the electrode and the weight measured with an electronic balance. The density was calculated from the measured film thickness.

[0395] [Table 2]

[0396] [Table 3]

[0397] Next, a method for manufacturing a power storage device will be described. One positive electrode has a positive electrode active material layer on one side of the body, and one negative electrode has a negative electrode active material layer on one side of the negative electrode current collector. In other words, each sample in this example had one positive electrode active material layer and one negative electrode active material layer. It has a configuration including an active material layer.

[0398] First, the positive electrode, negative electrode, and first separator were cut into pieces. The size of the positive electrode was 20.49 mm. cm 2 The negative electrode is 23.84 cm 2 The size of the first separator is 24.75 cm 2 It was decided.

[0399] As separators, Sample A1, Sample A2, Sample B1, Sample B2, Sample C1, Sample C2, Sample Sample D1, sample D2, sample E1, sample E2, sample F1, sample F2, comparative sample a1 and comparative sample Material a2 was made of cellulose fiber. Specifically, a 30 μm thick cellulose fiber manufactured by Nippon Kodo Paper Industries Co., Ltd. The sample B3 and sample B4 were made of polyethylene terephthalate-spun regenerated cellulose fiber (product number TF40). Specifically, a 46 μm thick polyphenylene sulfide film made by Toray was used. Two layers of sulfide paper (product number PS0020) were used.

[0400] Next, the positive electrode active material and the negative electrode active material on the tab region were peeled off to expose the current collector.

[0401] Next, the positive electrode and the negative electrode were stacked with the first separator sandwiched therebetween. The positive electrode active material layer and the negative electrode active material layer were laminated so as to face each other.

[0402] Next, leads were joined to the positive and negative electrodes by ultrasonic welding.

[0403] Next, the area where the stacked electrodes and leads were joined was further wrapped in a second separator. By doing so, the resin layer of the exterior body is dissolved by the subsequent heat treatment, and the This prevents the aluminum from coming into contact with the electrodes. The size of the second separator is 104 cm 2 It was decided.

[0404] Next, the exterior body was bonded by heating, leaving two of the four sides of the exterior body.

[0405] The exterior body was made of an aluminum film coated with a resin layer on both sides.

[0406] Next, the sealing layer on the lead and the sealing layer on the outer casing are placed so that they overlap, and then they are bonded by heating. At this time, the edges other than the edge into which the electrolyte was injected were joined.

[0407] Next, the outer packaging body and the positive electrode, separator, and negative electrode wrapped in the outer packaging body are subjected to a heat treatment to dry them. The heating conditions were a reduced pressure atmosphere (gauge pressure -100kPa) at 80℃ for 10 hours. It was a while.

[0408] Next, approximately 600 μL of electrolyte was injected from one unsealed side under an argon gas atmosphere. The comparative samples a1 and a2 were injected with the above-mentioned electrolyte a. Sample B1, Sample B2, Sample B3, and Sample B4 were filled with the above-mentioned electrolyte A. The aforementioned electrolyte B was injected into Samples C1 and C2. The aforementioned electrolyte C was injected into Sample D. Samples E1 and E2 were injected with the aforementioned electrolyte D. The electrolyte F described above was injected into samples F1 and F2.

[0409] After that, one side of the exterior body is sealed by heating under a reduced pressure atmosphere (gauge pressure -100kPa). Through the above steps, a thin power storage device was manufactured.

[0410] Next, sample A2, sample B2, sample C2, sample D2, sample E2, sample F2, sample B4 and the ratio The comparative sample a2 was subjected to heat treatment. The heating conditions were the same as those for the fluororubber described in the second embodiment. The temperature was set at 170°C for 15 minutes under atmospheric pressure, assuming the formation of a solid. After the temperature was raised to 70°C, each sample was placed in a thermostatic bath and removed after 15 minutes. In the test, no expansion was observed inside the exterior of each sample.

[0411] As a result of the above, Sample A1, Sample A2, Sample B1, Sample B2, Sample C1, Sample C2, Sample D1 , Sample D2, Sample E1, Sample E2, Sample F1, Sample F2, Sample B3, Sample B4, Comparative sample Sample a1 and comparative sample a2 were prepared.

[0412] <Measurement of charge / discharge characteristics> Next, the charge / discharge characteristics of each sample of this example at 25° C. were evaluated. The test was carried out using a constant current / constant voltage charging machine (manufactured by Toyo Systems Co., Ltd.). The charge / discharge cycle was 3 cycles at a rate of 0.1C. After that, a long-term cycle test was performed at a rate of 0.3C. After each charge and discharge, a 10-minute rest was performed. There was a gap.

[0413] The capacity obtained when the upper limit charging voltage of the positive electrode active material LiCoO2 is set to 4.3V The rate was calculated based on 170 mAh / g.

[0414] The charge and discharge curves of the comparative sample a1 are shown in FIG. 31(A), the comparative sample a2 in FIG. 31(B), and the sample A1 in Fig. 31(C), sample A2 in Fig. 31(D), sample B1 in Fig. 32(A), and sample B2 in Fig. 32(B), sample C1 in FIG. 32(C), sample C2 in FIG. 32(D), and sample D1 in FIG. 33(A). ), sample D2 in FIG. 33(B), sample E1 in FIG. 33(C), sample E2 in FIG. 33(D), sample Sample F1 is shown in Fig. 34(A), sample F2 in Fig. 34(B), sample B3 in Fig. 34(C), and sample B4 in Fig. 34(D). Figures 31(A), 31(B), 31(C), 31(D), and 32 (A), Fig. 32(B), Fig. 32(C), Fig. 32(D), Fig. 33(A), Fig. 33(B), Fig. 33(C), 33(D), 34(A), 34(B), 34(C) and 34(D) ) shows the capacity (Capacity) [mAh / g] on the horizontal axis and the voltage (Volta ge) [V]. For each sample, the 1st cycle and the 300th cycle The charge and discharge characteristics of the 300th The capacity is shown as a capacity per weight of the positive electrode active material.

[0415] In samples that were heated at 170°C for 15 minutes, the capacity decreased after repeated charge and discharge. It was confirmed that the hexafluorophosphate-containing sample a2 was superior to the comparative sample a2 without the hexafluorophosphate. Samples A2, B2, C2, and D2, which are embodiments of the present invention containing lithium phosphate It was confirmed that the decrease in capacity after repeated charge and discharge was suppressed in Sample B1 and Sample B4.

[0416] The discharge capacity cycle characteristics of the comparative samples a1 and a2 are shown in FIG. 35(A). Sample A2 is shown in FIG. 35(B), Samples B1 and B2 are shown in FIG. 35(C), and Samples C1 and C2 are shown in FIG. 35(D), sample D1 and sample D2 are shown in FIG. 36(A), and sample E1 and sample E2 are shown in FIG. (B), samples F1 and F2 are shown in Fig. 36(C), and samples B3 and B4 are shown in Fig. 36(D). 35(A), 35(B), 35(C), 35(D), 36(A), 3 6(B), 36(C) and 36(D), the horizontal axis is cycles [time es], and the vertical axis shows capacity [mAh / g].

[0417] The cycle characteristics of the discharge capacity retention rate of the comparative sample a1 and the comparative sample a2 are shown in FIG. 37(A). 1 and sample A2 are shown in FIG. 37(B), sample B1 and sample B2 are shown in FIG. 37(C), and sample C1 and sample Sample C2 is shown in FIG. 37(D), Sample D1 and Sample D2 are shown in FIG. 38(A), and Sample E1 and Sample E2 are shown in FIG. 38(B), samples F1 and F2 are shown in FIG. 38(C), samples B3 and B4 are shown in FIG. D). Figure 37(A), Figure 37(B), Figure 37(C), Figure 37(D), Figure 38(A) 38(B), 38(C) and 38(D), the horizontal axis represents cycles [ times], and the vertical axis shows the capacity retention rate [% The capacity retention rate is the ratio of the discharge capacity at each cycle to the maximum discharge capacity of each sample. The capacitance ratio is shown.

[0418] In samples that were heated at 170°C for 15 minutes, the capacity decreased after repeated charge and discharge. It was confirmed that the hexafluorophosphate-containing sample a2 was superior to the comparative sample a2 without the hexafluorophosphate. Samples A2, B2, C2, and D2, which are embodiments of the present invention containing lithium phosphate It was confirmed that the decrease in capacity after repeated charge and discharge was suppressed in Sample B1 and Sample B4.

[0419] In one embodiment of the present invention, a highly heat-resistant lithium bis(pentafluoroethanesulfonyl) arsenate is used. LiBETA plays the main role of supplying the lithium ions that act as carrier ions. This shows that the decrease in capacity after repeated discharge can be suppressed even after heat treatment. Furthermore, by containing lithium hexafluorophosphate, the anode current collector A passive film is formed on the surface of aluminum when it is heated to 170°C or when it is charged and discharged. It is believed that the characteristics were able to be maintained in a good state. The capacity decrease was larger than that of a2. Samples E2 and F2 were lithium hexafluorophosphate. Because the concentration is high, lithium hexafluorophosphate becomes LiF when heated at 170°C. It decomposes into PF5, and the PF5 decomposes the solvent, causing deterioration of battery characteristics such as a decrease in capacity. It is thought that lithium hexafluorophosphate (LiPF6) was deposited on the surface of the current collector. It has been found that it is desirable to use an amount that can form a passivation film on the surface of the metal.

[0420] In one embodiment of the present invention, the solute is lithium bis(pentafluoroethanesulfonyl)amide. (LiBETA) and lithium hexafluorophosphate (LiPF6) It was found that even if heat treatment was performed, the capacity was less likely to decrease after repeated charge and discharge.

[0421] The cycle characteristics of the energy density of the comparative sample a1 and the comparative sample a2 are shown in FIG. 39(A). 1 and sample A2 are shown in FIG. 39(B), sample B1 and sample B2 are shown in FIG. 39(C), and sample C1 and sample Sample C2 is shown in Figure 39(D), Sample D1 and Sample D2 are shown in Figure 40(A), and Sample E1 and Sample E2 are shown in Figure 41(B). 40(B), samples F1 and F2 are shown in FIG. 40(C), samples B3 and B4 are shown in FIG. D). Figure 39(A), Figure 39(B), Figure 39(C), Figure 39(D), Figure 40(A) 40(B), 40(C) and 40(D) ​​show the horizontal axis representing cycles [ times], and the vertical axis shows energy density [mWh / g]. The energy density is shown in Figures 31(A), 31(B), 31(C), and 3 1(D), Fig. 32(A), Fig. 32(B), Fig. 32(C), Fig. 32(D), Fig. 33(A), Figure 33(B), Figure 33(C), Figure 33(D), Figure 34(A), Figure 34(B), Figure 34(C ) and the discharge curve in FIG. 34(D), which is the product of the discharge capacity and the voltage.

[0422] The cycle characteristics of the energy density retention rate of the comparative sample a1 and the comparative sample a2 are shown in FIG. Samples A1 and A2 are shown in FIG. 41(B), samples B1 and B2 are shown in FIG. 41(C), and sample C1 and sample C2 in FIG. 41(D), sample D1 and sample D2 in FIG. 42(A), sample E1 and sample E2 in Fig. 42(B), specimens F1 and F2 in Fig. 42(C), specimens B3 and B4 in Fig. 42(D). Figures 41(A), 41(B), 41(C), 41(D), and 42 In (A), (B), (C) and (D), the horizontal axis represents cycles. s) [times], and the vertical axis shows the energy density maintenance rate (Energy density The energy density retention rate is the energy density of each sample. The graph shows the ratio of the energy density in each cycle to the maximum energy density.

[0423] In the sample that was heat treated at 170°C for 15 minutes, the energy density decreased after repeated charge and discharge. It was confirmed that the amount of lithium hexafluorophosphate in the sample a2 was reduced. Samples A2, B2, and C2, which are embodiments of the present invention containing lithium hexafluorophosphate, In Samples D2 and B4, the decrease in energy density after repeated charge and discharge was suppressed. I was able to confirm this.

[0424] In one embodiment of the present invention, a highly heat-resistant lithium bis(pentafluoroethanesulfonyl) arsenate is used. LiBETA plays the main role of supplying the lithium ions that act as carrier ions. This makes it possible to suppress the decrease in energy density after repeated discharges even when heat treatment is performed. Furthermore, by containing lithium hexafluorophosphate, it was found that the positive electrode current collector A passive film is formed on the surface of the aluminum used in this test when it is heated to 170°C or when it is charged and discharged. It is believed that the cycle characteristics were maintained in a good state. The decrease in energy density was greater than that of the comparative sample a2. Since the lithium fluorophosphate concentration is high, the hexafluorophosphate is obtained by heating at 170°C. The lithium oxide decomposed into LiF and PF5, and the PF5 decomposed the solvent, so the energy density It is thought that the battery characteristics have deteriorated, such as the capacity of lithium hexafluorophosphate decreasing. It is desirable to use an amount of LiPF6 that can form a passivation film on the surface of the current collector. I found out that...

[0425] In one embodiment of the present invention, the solute is lithium bis(pentafluoroethanesulfonyl)amide. (LiBETA) and lithium hexafluorophosphate (LiPF6) Even if heat treatment is performed, the energy density is less likely to decrease after repeated charging and discharging. I understand.

[0426] Comparative sample a2, sample A2, sample B2, sample C2, sample D2, which were heat-treated at 170°C. For samples E2, F2, and B4, the concentration of lithium hexafluorophosphate relative to the electrolyte The relationship between the temperature and the capacity retention rate is shown in Table 3 and Figure 43(A). The concentration of lithium fluoride phosphate (LiPF6 concentration) [wt%] is shown. The vertical axis shows the capacity retention rate (%). In (A), the black circles indicate comparative sample a2 and sample A2, which use cellulose fiber for the separator. , data for samples B2, C2, D2, E2 and F2 are shown, and crosses indicate separators. The data for sample B4, which uses polyphenylene sulfide as the capacitor, is shown below. Figure 37(A), Figure 37(B), Figure 37(C), Figure 37(D), Figure 38(A), Figure 38(B ), and the values ​​at the 300th cycle of each sample shown in Figures 38(C) and 38(D) are shown. .

[0427] Comparative sample a2, sample A2, sample B2, sample C2, and sample B2 were heated at 170°C for 15 minutes. For Sample D2, Sample E2, Sample F2 and Sample B4, the lithium hexafluorophosphate The relationship between the concentration of ammonium and the energy density maintenance rate is shown in Table 4 and Figure 43(B). B) The horizontal axis is the concentration of lithium hexafluorophosphate (LiPF6 concentration) n) [wt%], and the vertical axis represents the energy density maintenance rate (Energy density In Figure 43(B), black circles indicate cells in the separator. Comparative sample a2, sample A2, sample B2, sample C2, sample D2, sample E2 using loin fiber The data for sample F2 are shown, and the cross marks indicate that polyphenylene sulfide was used as the separator. The data for sample B4 are shown in Fig. 41(A), Fig. 41(B), and Fig. 41(C). 41(C), Figure 41(D), Figure 42(A), Figure 42(B), Figure 42(C), Figure 42(D) The values ​​shown are those at the 300th cycle for each sample.

[0428] [Table 4]

[0429] As shown in Table 4, Figures 43(A) and 43(B), when lithium hexafluorophosphate is not used, In comparison with the comparative sample a2, the samples A2, B2, C2, and D2, which are embodiments of the present invention, Sample B4 showed high capacity retention and energy retention after repeated charge and discharge. On the other hand, samples E2 and F2, which have a high concentration of lithium hexafluorophosphate, maintained their capacity. The durability and energy retention rate have decreased.

[0430] From these results, it was found that ethylene carbonate (EC) and propylene carbonate (PC) were used as electrolytes. Polyvinylcarbonate (PC), vinylene carbonate (VC), lithium bis(pentafluoroethane) Lithium hexafluorophosphate (LiBETA) and lithium hexafluorophosphate The weight ratio of lithium to the electrolyte is preferably 0.01 wt% or more and 1.9 wt% or less. In addition, the weight ratio of lithium hexafluorophosphate to the electrolyte was 0.05 wt. It was found that a concentration of 1.2 wt% or more is more preferable. The weight ratio of the polymer to the electrolyte is more preferably 0.1 wt% or more and 0.8 wt% or less. I found out that...

[0431] As the solute of the electrolyte, lithium bis(pentafluoroethanesulfonyl)amide (LiB By using ETA and lithium hexafluorophosphate, a highly heat-resistant storage battery can be obtained. It was found that... [Example]

[0432] In this example, a power storage device according to one embodiment of the present invention was manufactured based on Embodiment 1. A cycle test was carried out at 45°C with the storage device.

[0433] <Sample preparation method> In this example, a power storage device 500 shown in FIG. 1A was manufactured. Reveal.

[0434] The samples to which one embodiment of the present invention was applied were four samples in total: Sample G1, Sample G2, Sample H1, and Sample H2. The samples prepared for comparison were two samples, Comparative Sample A3 and Comparative Sample A4. do.

[0435] Samples G1, G2, H1, and H2 contain lithium bis(pentafluoroethylene) as the solute. Lithium hexafluorophosphate (LiBETA) and ethanesulfonylamide (LiBETA) were used. 1. Samples G2, H1, and H2 differ in the concentration of lithium hexafluorophosphate. Comparative sample a3 and comparative sample a4 contain lithium bis(pentafluoroethanesulfonyl) as the solute. Lithium hexafluorophosphate (LiBETA) was used, but lithium hexafluorophosphate was not used.

[0436] Samples G1, G2, H1, H2, comparative sample a3 and comparative sample a4 are separators. Cellulose fiber was used as the material.

[0437] After the electricity storage device 500 was fabricated, the samples G2, H2, and a4 were subjected to a 170 This heat treatment was carried out at 15°C for 15 minutes. The sample AG, sample H1, and comparative sample a3 were subjected to heating. No processing was performed.

[0438] Table 5 shows the electrolyte, separator, and heat treatment conditions for each sample.

[0439] [Table 5]

[0440] A method for preparing the electrolyte will be described.

[0441] Electrolyte a was used as the electrolyte for comparative sample a3 and comparative sample a4. , the explanation will be omitted since the previous Example 1 can be referred to.

[0442] The electrolyte G used in Samples G1 and G2 will be described. C) and propylene carbonate (PC) in a volume ratio of 1:1. carbonate (VC) and lithium bis(pentafluoroethanesulfonyl)amine. Electrolyte G was prepared by dissolving vinyl phosphate (LiBETA) and lithium hexafluorophosphate. The amount of VC dissolved in the electrolyte G was 1 wt %. Lithium bis(pentafluoroethanesulfonyl)amide (LiBETA) is used in the electrolyte G. The amount of lithium hexafluorophosphate dissolved in the solution was 1 mol / L. The amount of the compound dissolved in G was 0.26 wt % in terms of weight ratio.

[0443] The electrolyte H used in Samples H1 and H2 will be described. C) and propylene carbonate (PC) in a volume ratio of 1:1. carbonate (VC) and lithium bis(pentafluoroethanesulfonyl)amine. The electrolyte H was prepared by dissolving vinyl phosphate (LiBETA) and lithium hexafluorophosphate. The amount of VC dissolved in the electrolyte H was 1 wt %. Lithium bis(pentafluoroethanesulfonyl)amide (LiBETA) is used in the electrolyte H The amount of lithium hexafluorophosphate dissolved in the solution was 1 mol / L. The amount of H dissolved was 0.51 wt % in terms of weight ratio.

[0444] Ethylene carbonate (EC) and propylene carbonate (PC) are mixed in a volume ratio of 1:1. The combined mixture is a lithium battery grade (product code number LBG- Vinylene carbonate (VC) was used. Terry grade (product code number LBG-84923) was used. Fluoroethanesulfonyl)amide (LiBETA) is a Manufactured by Liquids Technologies Inc. (Product Number KI-0016-H P). Lithium hexafluorophosphate was used as the lithium battery grade material manufactured by Kishida Chemical. (Product code number LBG-45860) was used.

[0445] Next, a negative electrode was prepared. The method for preparing the negative electrode can be explained by referring to Example 1. is omitted.

[0446] Next, a positive electrode was prepared. The method for preparing the positive electrode can be explained by referring to Example 1. is omitted.

[0447] The average values ​​of the active material loading, film thickness, and density of the prepared positive electrode active material layer are shown in Table 6. Shown in Table 7.

[0448] [Table 6]

[0449] [Table 7]

[0450] Next, a method for manufacturing a power storage device will be described. One positive electrode has a positive electrode active material layer on one side of the body, and one negative electrode has a negative electrode active material layer on one side of the negative electrode current collector. In other words, each sample in this example had one positive electrode active material layer and one negative electrode active material layer. It has a configuration including an active material layer.

[0451] First, the positive electrode, negative electrode, and first separator were cut into pieces. The size of the positive electrode was 20.49 mm. cm 2 The negative electrode is 23.84 cm 2 The size of the first separator is 24.75 cm 2 It was decided.

[0452] As separators, samples G1, G2, H1, H2, comparative sample a3 and comparative sample Material a4 was made of cellulose fiber. Specifically, a 30 μm thick cellulose fiber made by Nippon Kodo Paper Industries Co., Ltd. Agent-spun regenerated cellulose fibers (product number TF40) were used.

[0453] Next, the positive electrode active material and the negative electrode active material on the tab region were peeled off to expose the current collector.

[0454] Next, the positive electrode and the negative electrode were stacked with the first separator sandwiched therebetween. The positive electrode active material layer and the negative electrode active material layer were laminated so as to face each other.

[0455] Next, leads were joined to the positive and negative electrodes by ultrasonic welding.

[0456] Next, the area where the stacked electrodes and leads were joined was further wrapped in a second separator. By doing so, the resin layer of the exterior body is dissolved by the subsequent heat treatment, and the This prevents the aluminum from coming into contact with the electrodes. The size of the second separator is 104 cm 2 It was decided.

[0457] Next, the exterior body was bonded by heating, leaving two of the four sides of the exterior body.

[0458] The exterior body was made of an aluminum film coated with a resin layer on both sides.

[0459] Next, the sealing layer on the lead and the sealing layer on the outer casing are placed so that they overlap, and then they are bonded by heating. At this time, the edges other than the edge into which the electrolyte was injected were joined.

[0460] Next, the outer packaging body and the positive electrode, separator, and negative electrode wrapped in the outer packaging body are subjected to a heat treatment to dry them. The heating conditions were a reduced pressure atmosphere (gauge pressure -100kPa) at 80℃ for 10 hours. It was a while.

[0461] Next, approximately 600 μL of electrolyte was injected from one unsealed side under an argon gas atmosphere. The comparative samples a3 and a4 were injected with the above-mentioned electrolyte a. Sample G2 was injected with the aforementioned electrolyte G. Sample H1 and sample H2 were injected with the aforementioned electrolyte H. Ta.

[0462] After that, one side of the exterior body is sealed by heating under a reduced pressure atmosphere (gauge pressure -100kPa). Through the above steps, a thin power storage device was manufactured.

[0463] Next, the samples G2, H2, and a4 were subjected to heat treatment. Assuming the formation of an integrated structure with the fluororubber described in Mode 2, the test was carried out at 170°C for 15 minutes under atmospheric pressure. Specifically, after the temperature of the thermostatic bath was raised to approximately 170°C, each sample was placed in the thermostatic bath and after 15 minutes During the heat treatment, no expansion was observed inside the exterior of each sample. There wasn't.

[0464] As a result of the above, Sample G1, Sample G2, Sample H1, Sample H2, Comparative Sample a3, and Comparative Sample a4 was produced.

[0465] <Measurement of charge / discharge characteristics> Next, the charge / discharge characteristics of each sample of this example at 45° C. were evaluated. The test was carried out using a constant current / constant voltage charging machine (manufactured by Toyo Systems Co., Ltd.). The charge and discharge were performed at a constant voltage of 2.5 V. A 10-minute rest period was then provided, and two charge / discharge cycles were performed.

[0466] The capacity obtained when the upper limit charging voltage of the positive electrode active material LiCoO2 is set to 4.3V The rate was calculated based on 170 mAh / g.

[0467] The charge and discharge curves of comparative sample a3 are shown in FIG. 44(A), comparative sample a4 in FIG. 44(B), and sample G1 in Fig. 44(C), sample G2 in Fig. 44(D), sample H1 in Fig. 45(A), and sample H2 in Fig. 45(B). Figures 44(A), 44(B), 44(C), 44(D), and 45 In (A) and (B) of FIG. 45, the horizontal axis indicates the capacity (mAh / g) and the vertical axis indicates the capacity (mAh / g). The axis indicates voltage (V). t) and 300th cycle (300th) charge and discharge The capacity indicates the capacity per weight of the positive electrode active material. .

[0468] In addition, in the comparative sample a3 and the comparative sample a4 which do not contain lithium hexafluorophosphate, 30 At the 0th cycle, the capacity was close to zero.

[0469] The discharge capacity cycle characteristics of the comparative samples a3 and a4 are shown in FIG. 46(A), and the discharge capacity cycle characteristics of the comparative samples G1 and Sample G2 is shown in Figure 46(B), and samples H1 and H2 are shown in Figure 46(C). In Figure 46(B) and Figure 46(C), the horizontal axis indicates cycles (times). The vertical axis indicates the capacity (mAh / g).

[0470] The cycle characteristics of the discharge capacity retention rate of the comparative samples a3 and a4 are shown in FIG. 47(A). Samples G1 and G2 are shown in Figure 47(B), and samples H1 and H2 are shown in Figure 47(C). In Figures 47(A), 47(B) and 47(C), the horizontal axis represents cycles [times ], and the vertical axis indicates capacity retention [%]. The capacity retention rate is the ratio of the discharge capacity at each cycle to the maximum discharge capacity of each sample. The figure shows the rate.

[0471] Comparative samples a3 and a4, which do not contain lithium hexafluorophosphate, were tested for about 150 cycles. At 45°C, the capacity was close to zero. Bis(pentafluoroethanesulfonyl)amide (LiBETA) is used as the positive electrode current collector. It is believed that the aluminum used was corroded. Compared to comparative sample A3 and comparative sample A4, Samples G1, G2, H1, and H2, which are embodiments of the present invention, were subjected to charge-discharge cycles. The result was that the capacity loss was small even after repeated heating at 170°C and 15 Despite the heat treatment, the capacity retention rate was high. Lithium oxide forms a passive film on the surface of aluminum, which prevents the aluminum from being damaged even after heat treatment. It is believed that this has suppressed corrosion of the aluminum.

[0472] The cycle characteristics of the energy density of the comparative sample a3 and the comparative sample a4 are shown in FIG. 48(A). Samples G1 and G2 are shown in Figure 48(B), and samples H1 and H2 are shown in Figure 48(C). In Figures 48(A), 48(B) and 48(C), the horizontal axis represents cycles [times The vertical axis indicates the energy density [mWh / g]. Energy density is shown in Figure 44(A), Figure 44(B), Figure 44(C), Figure 44(D), This is the product of the discharge capacity and the voltage shown in the discharge curves of Figures 45(A) and 45(B).

[0473] The cycle characteristics of the energy density retention rate of the comparative sample a3 and the comparative sample a4 are shown in FIG. 49(A). Samples G1 and G2 are shown in FIG. 49(B), and samples H1 and H2 are shown in FIG. 49(C). 49(A), 49(B) and 49(C) show the horizontal axis representing cycles [ti mes], and the vertical axis shows the energy density retention rate (Energy density ret The energy density retention rate is the energy density of each sample. The graph shows the ratio of the energy density in each cycle to the maximum value.

[0474] Comparative samples a3 and a4, which do not contain lithium hexafluorophosphate, were tested for about 150 cycles. At this temperature, the energy density was close to zero. Therefore, samples G1, G2, H1, and H2, which are embodiments of the present invention, were tested in a charge-discharge cycle. The decrease in capacity was small even after repeated heating. Despite the 5-minute heat treatment, the energy density was maintained at a high rate.

[0475] For comparative sample a3, sample G2 and sample H2 that were heat-treated at 170°C, the The relationship between the concentration of lithium hexafluorophosphate and the capacity retention rate is shown in Table 5 and Figure 50(A). In Figure 50(A), the horizontal axis indicates the concentration of lithium hexafluorophosphate (LiPF6concentration). The vertical axis shows the capacity retention rate (wt%). The capacity retention rate is shown in Figures 47(A), 47(B) and 47(C). The values ​​shown are those at the 300th cycle for each sample.

[0476] Comparative sample a4, sample G2 and sample H4 were subjected to a heat treatment at 170°C for 15 minutes. The relationship between the concentration of lithium hexafluorophosphate and the energy density retention rate is shown in Table 8 and The graph in Fig. 50(B) shows the relationship between the concentration of lithium hexafluorophosphate (LiPF 6 concentration) [wt%], and the vertical axis shows the energy density maintenance rate (E Energy density retention [%]. The rate is the 300th cycle of each sample shown in Figures 49(A), 49(B) and 49(C). The values ​​shown are:

[0477] [Table 8]

[0478] As shown in Table 8, Figures 50(A) and 50(B), when lithium hexafluorophosphate is not used, Compared with the comparative sample a4, the samples G2 and H2 according to the present invention showed a The results showed that the capacity retention rate and energy retention rate were high after charging.

[0479] From these results, it was found that ethylene carbonate (EC) and propylene carbonate (PC) were used as electrolytes. Polyvinylcarbonate (PC), vinylene carbonate (VC), lithium bis(pentafluoroethane) Lithium hexafluorophosphate (LiBETA) and lithium hexafluorophosphate The weight ratio of lithium to the electrolyte is preferably 0.01 wt% or more and 1.9 wt% or less. In addition, the weight ratio of lithium hexafluorophosphate to the electrolyte was 0.05 wt. It was found that a concentration of 1.2 wt% or more is more preferable. The weight ratio of the polymer to the electrolyte is more preferably 0.1 wt% or more and 0.8 wt% or less. I found out that...

[0480] As the solute of the electrolyte, lithium bis(pentafluoroethanesulfonyl)amide (LiB By using ETA) and lithium hexafluorophosphate, It was found that the resulting battery had good charge / discharge characteristics and high heat resistance. [Example]

[0481] In this example, the reaction between aluminum used as the positive electrode current collector and the electrolyte was confirmed. Explain the results.

[0482] <Sample preparation method> In this example, a storage battery according to one embodiment of the present invention was manufactured. After heat treatment at 170° C. for 15 minutes, The positive electrode was removed from the battery and the aluminum surface of the positive electrode was analyzed for composition by XPS measurement. The battery that was heated at 170°C for 15 minutes was designated as battery 1. The positive electrode thus obtained is designated as positive electrode 1. For comparison, after the positive electrode was prepared, the battery was assembled and heated. An XPS analysis was also carried out on a sample that had not been treated (Comparative Positive Electrode 1).

[0483] The method for producing the positive electrode will be described. The method for producing the positive electrode was the same as that for the comparative positive electrode 1 and the storage battery 1 (positive electrode 1) is common.

[0484] The positive electrode active material has a specific surface area of ​​0.21 m 2 / g, and the average particle size was 10 μm. Polyvinylidene fluoride (PVDF) is used as the adhesive, and acetylene black is used as the conductive additive. The blend of LiCoO2, PVDF, and acetylene black was The ratio of acetylene black to PVDF was 95:3:2 (wt%).

[0485] First, acetylene black and PVDF were mixed and kneaded in a kneader to obtain a fifth mixture. Ta.

[0486] Next, an active material was added to the fifth mixture to obtain a sixth mixture.

[0487] Next, N-methyl-2-pyrrolidone (NMP) as a solvent was added to the fourth mixture, and the mixture was kneaded. The mixture was kneaded using a mixer. A slurry was prepared by the above steps.

[0488] Next, the mixture was mixed in a large mixer.

[0489] Next, the slurry was applied to the positive electrode current collector using a continuous coater. An aluminum current collector (film thickness: 20 μm) was used, and the coating speed was 0.2 m / min.

[0490] Thereafter, the solvent of the slurry applied to the positive electrode current collector was evaporated using a drying furnace. The curing was carried out in an air atmosphere, and the curing was carried out at 70°C for 7.5 minutes, followed by 90°C for 7.5 minutes. The following processing was carried out.

[0491] Next, heat treatment was performed at 170°C for 10 hours under a reduced pressure atmosphere (gauge pressure -100kPa). Thereafter, the positive electrode active material layer was pressed by a roll press method to be compacted.

[0492] Through the above steps, a positive electrode active material layer was formed on one surface of the positive electrode current collector.

[0493] The sample produced through the steps up to this point was designated as comparative positive electrode 1.

[0494] Furthermore, a method for manufacturing the storage battery 1 will be described.

[0495] The method for producing the negative electrode will be described.

[0496] The negative electrode active material has a specific surface area of ​​6.3 m 2 / g, spherical natural graphite with an average particle size of 15 μm (Nippon Graphite The binder used was carboxymethyl cellulose (CGB-15 manufactured by Kogyo Co., Ltd.). The polymerization degree of the CMC-Na used was 60. 0 to 800, and the viscosity of the aqueous solution when used as a 1 wt% aqueous solution is 300 mPa·s or more. The values ​​were in the range of 500 mPa·s or less. The graphite:CMC-Na:SBR ratio was 97:1.5:1.5 (wt%).

[0497] First, the CMC-Na powder and the active material were mixed and kneaded in a kneader to obtain a seventh mixture.

[0498] Next, a small amount of water was added to the seventh mixture, and the mixture was kneaded to obtain an eighth mixture. The term "hard kneading" refers to kneading with high viscosity.

[0499] Next, water was further added, and the mixture was kneaded using a kneader to obtain a ninth mixture.

[0500] Next, a 50 wt% aqueous dispersion of SBR was added and mixed using a mixer. The mixture was defoamed at 100° C. to obtain a slurry.

[0501] Next, the slurry was applied to the negative electrode current collector using a continuous coater. The coating speed was 0.75 m / min.

[0502] Next, the solvent of the slurry applied to the negative electrode current collector was evaporated using a drying oven. After treatment at 50°C for 120 seconds in an atmosphere, treatment at 80°C for 120 seconds was performed. Furthermore, the sample was treated at 100°C for 10 hours under a reduced pressure atmosphere (gauge pressure -100kPa). was carried out.

[0503] Through the above steps, a negative electrode active material layer was formed on one surface of the negative electrode current collector, thereby producing a negative electrode.

[0504] A method for producing the electrolyte of the storage battery 1 will be described.

[0505] Ethylene carbonate (EC) and propylene carbonate (PC) are mixed in a volume ratio of 1:1. Vinylene carbonate (VC) was added to the combined mixture, and lithium bis(pentafluoro) Lithium hexafluorophosphate (LiBETA) and lithium hexafluorophosphate were dissolved in the solution. Electrolyte B2 was prepared. Vinylene carbonate (VC) was mixed with electrolyte A in a weight ratio of 1 wt. The amount of lithium bis(pentafluoroethanesulfonyl)amide (L iBETA) was dissolved in electrolyte B2 in an amount that gave a molar concentration of 1 mol / L. Lithium fluoride phosphate was dissolved in an amount of 0.27 wt% by weight in electrolyte B2. The electrolyte B2 used in this example was prepared by the same method as the electrolyte B shown in Example 1. do.

[0506] Next, the positive electrode, the negative electrode, and the first separator were cut into pieces. cm 2 The negative electrode is 23.84 cm 2 The size of the first separator is 24.75 cm 2 I decided. I decided.

[0507] The separator used was cellulose fiber. Specifically, a 30 μm thick cellulose fiber (Nippon Kogyo Paper Co., Ltd.) A commercially available solvent-spun regenerated cellulose fiber (product number TF40) was used.

[0508] Next, the positive electrode active material and the negative electrode active material on the tab region were peeled off to expose the current collector.

[0509] Next, the positive electrode and the negative electrode were stacked with a separator sandwiched between them. The electrode active material layer and the negative electrode active material layer were laminated so as to face each other.

[0510] Next, leads were attached to the positive and negative electrodes by ultrasonic welding.

[0511] Next, the area where the stacked electrodes and leads were welded was wrapped with a separator. As a result, the resin layer of the exterior body is melted by the subsequent heat treatment, and the aluminum layer of the exterior body is melted. The size of the second separator is 104 cm 2 It was decided.

[0512] Next, the exterior body was bonded by heating, leaving two of the four sides of the exterior body.

[0513] The exterior body was made of an aluminum film coated with a resin layer on both sides.

[0514] Next, the sealing layer on the lead and the sealing layer on the outer casing are placed so that they overlap, and then they are bonded by heating. At this time, the edges other than the edge into which the electrolyte was injected were joined.

[0515] Next, the outer packaging body and the positive electrode, separator, and negative electrode wrapped in the outer packaging body are subjected to a heat treatment to dry them. The heating conditions were a reduced pressure atmosphere (gauge pressure -100kPa) at 80℃ for 10 hours. It was a while.

[0516] Next, in an argon gas atmosphere, approximately 600 μL of electrolyte B2 was injected from one unsealed side. Injected.

[0517] After that, one side of the exterior body is sealed by heating under a reduced pressure atmosphere (gauge pressure -100kPa). did.

[0518] In this way, the storage battery 1 was produced.

[0519] Next, the storage battery 1 was subjected to a heat treatment. The heating conditions were the same as those for the fluororubber described in the second embodiment. The temperature was set at 170°C for 15 minutes under atmospheric pressure, assuming the formation of a single piece. After the temperature was raised to about 170°C, each sample was placed in a thermostatic chamber, and after 15 minutes, the storage battery 1 was taken out.

[0520] Next, the storage battery 1 was disassembled in a glove box with a nitrogen atmosphere, and the positive electrode 1 was taken out. The positive electrode 1 was washed with dimethyl carbonate (DMC) and dried.

[0521] Thus, the positive electrode 1 was fabricated.

[0522] <X-ray Photoelectron Spectroscopy> Next, X-ray photoelectron spectroscopy (XPS) was performed on the comparative positive electrode 1 and the positive electrode 1. The X-ray was irradiated onto the surface where the positive electrode active material of aluminum was not coated. The position where the XPS measurement was performed is shown in FIG. 51. In FIG. 51, the arrow indicates the irradiation direction of the X-ray.

[0523] The XPS measurement was carried out using a Quantera SXM manufactured by PHYSICAL ELECTRONICS. Monochromatized Al Kα rays (1486.6 eV) were used as the X-ray source. The detection area was 100 μmφ. The take-out angle was 45°. The detection depth is considered to be about 4 nm to 5 nm.

[0524] The spectra of Al2p obtained by the XPS measurement are shown in FIG. 52(A), C1s in FIG. 52(B), O1s in FIG. 52(C), S2p in FIG. 53(A), Li1s in FIG. 53(B), F1s in FIG. 53(C), P2s in FIG. 54(A), N1s in FIG. 54(B), Si2s in FIG. 54(C), Na1s in FIG. 55(A), and Ca2p in FIG. 55(B). FIGS. 52(A), FIG. 52(B), FIG. 52(C), FIG. 53(A), FIG. 53(B), FIG. 53(C), FIG. 54(A), FIG. 54(B), FIG. 54(C), FIG. 55(A), and FIG. 55(B) show the binding energy [eV] on the horizontal axis and the intensity of the photoelectrons (Intensity) (arbitrary unit) on the vertical axis. ​

[0525] In the comparative positive electrode 1, which was not subjected to heat treatment, Al, O, C and trace amounts of F and Si were detected. In the heat-treated positive electrode 1, Al, F, O, Li, C, and trace amounts of P and N were , Na, and Ca were detected.

[0526] The quantitative values ​​of each element obtained from the XPS spectrum are shown in Table 9. The quantitative accuracy is ±1 The detection limit is about 1 atomic %, although it differs depending on the element.

[0527] [Table 9]

[0528] Compared to comparative positive electrode 1, positive electrode 1 tended to have less O and more F. The Al in cathode 1 was in the oxidized and metallic states, whereas the Al in cathode 2 was in the fluorinated and metallic states. The Li detected in the positive electrode 1 was mainly LiPFx, LiF, etc. The Si detected in positive electrode 1 was mainly present in an oxidized state. It is thought that C exists mainly in the CC and CH states.

[0529] From the above results, it can be seen that the aluminum heated together with the electrolyte, which is one embodiment of the present invention, has a surface It was found that a film containing aluminum fluoride was formed. When a secondary battery containing lithium fluorophosphate undergoes a heating process during the manufacturing process, the positive electrode aggregate It is suggested that a coating is formed on the electrode, and that this coating contributes to suppressing deterioration during charge-discharge cycles. was done. [Example]

[0530] In this example, lithium bis(pentafluoroethanesulfonyl)amide (LiBETA The results of checking the heat resistance of the above-mentioned product will be explained below.

[0531] <Sample preparation method> The samples used in this example were a total of three samples, Sample 1, Sample 2 and Sample 3.

[0532] Sample 1 will be described. Lithium bis(pentafluoroethanesulfonyl)amide (L iBETA) was used as sample 1. LiBETA is a product of IoLiTec Ionic Liquids Technology Measurements were performed in powder form using a product manufactured by Ogis Inc. (product number KI-0016-HP). went.

[0533] Sample 2 will be explained. Ethylene carbonate (EC) and propylene carbonate ( A mixture of ethylene carbonate (EC) and ethylene carbonate (PC) in a volume ratio of 1:1 was used as sample 2. ) and propylene carbonate (PC) in a volume ratio of 1:1. The lithium battery grade (product code number LBG-00798) manufactured by Samsung Electronics Co., Ltd. was used.

[0534] Sample 3 will be explained. Ethylene carbonate (EC) and propylene carbonate ( PC) in a volume ratio of 1:1, and lithium bis(pentafluoroethanesulfonyl) Sample 3 was prepared by dissolving lithium bis(pentafluoro)amide (LiBETA). LiBETA was used in the sample 3 at a molar concentration of 1 mol / The amount of ethylene carbonate (EC) dissolved was 1 L. This produced Sample 3. and propylene carbonate (PC) in a volume ratio of 1:1. The lithium battery grade (product code number LBG-00798) was used. LiBETA is a fluoropolymer of methyl bis(pentafluoroethanesulfonyl)amide (LiBETA). Manufactured by Ionic Liquids Technologies Inc. (Product Number KI -0016-HP) was used.

[0535] <Thermogravimetry - Differential thermal analysis> Next, thermogravimetry-differential thermal analysis (TG-DTA) TG-DTA (Congenital Thermal Analysis) was performed. The measurement was carried out using a Rigaku Thermo Mass Photo under a helium flow (flow Measurements were performed from room temperature to 600°C at a temperature rise rate of 10°C / min. It was.

[0536] The TG-DTA measurement results for sample 1 are shown in Figure 56(A), sample 2 in Figure 56(B), and sample 3 in Figure 57 In Figures 56(A), 56(B) and 57, the horizontal axis represents temperature. e) [℃], the left vertical axis shows the weight change rate ΔW [%], and the right vertical axis shows the amount of heat (Heat The weight change rate ΔW is the ratio of the initial weight (before heating) to the weight during heating. The weight change indicates the percentage change in weight of the sample, and a negative value indicates a weight loss due to heating.

[0537] Sample 1 began to lose weight around 330°C, and at around 420°C, it lost approximately 9% of its initial weight. The weight of the mixture was 5%. In addition, endothermic reactions were observed around 327.4°C and 416.7°C. The endothermic reaction at around 327.4°C was observed in the reaction of lithium bis(pentafluoroethanesulfonyl) This is thought to be due to the melting of LiBETA. At around 0°C, lithium bis(pentafluoroethanesulfonyl)amide (LiBE TA) was found to be stable.

[0538] Sample 2 began to lose weight around 150°C, and at around 235°C, it lost approximately -96% of its initial weight. % by weight. An endothermic reaction was observed around 232.5°C. The most recent endothermic reaction is that of ethylene carbonate (EC) and propylene carbonate (PC). This is thought to be due to evaporation.

[0539] Sample 3 began to lose weight around 150°C, and at around 300°C, it lost approximately -78% of its initial weight. %, and approximately -100% at around 450°C. The behavior of sample 2 is almost identical to that of ethylene carbonate. This is thought to be due to ethylene carbonate (EC) and propylene carbonate (PC). Therefore, at temperatures below 300°C, lithium bis(pentafluoroethanesulfonyl) It was found that the amide (LiBETA) was thermally stable. [Explanation of symbols]

[0540] 50 films 51 Film 52 Film 53 Embossing Roll 54 rolls 55 Embossing Roll 56 Embossing Roll 57 Embossing Roll 58 Embossing Roll 60 Direction of travel 115 Sealing layer 118 Joint 119 entrance 200 Secondary battery 203 Separator 203a area 203b area 207 Exterior body 211 Positive electrode 211a positive electrode 215 negative electrode 215a negative electrode 220 Sealing layer 221 Positive lead 225 Negative lead 230 Electrode assembly 231 Electrode assembly 250 Secondary battery 281 Tab Area 282 Tab Area 500 Electricity storage device 501 Positive electrode current collector 502 Positive electrode active material layer 503 Positive electrode 504 Negative electrode current collector 505 Negative electrode active material layer 506 negative electrode 507 Separator 508 Electrolyte 509 Exterior body 510 Positive lead 511 Negative lead 512 Joint 513 Curved section 514 Joint 518 Joint 520 Separator 521 Joint 529 Exterior body 700 Mobile Information Terminals 701 Case 702 Display Panel 703 Clasp 705A band 705B band 711 Operation button 712 Operation Button 730 Mobile Information Terminals 731 Case 732 Leak detection circuit 733 Power supply 734 Ammeter 735A band 736 Electrolyte 739 Functional Circuits 750 Energy Storage Device 751 Positive lead 752 Negative lead 753 Exterior body 760 Energy Storage Device 761 terminals 762 terminals 771 Wiring 772 Wiring 7100 Portable display devices 7101 Housing 7102 Display section 7103 Operation button 7104 Energy storage devices 7200 Personal Digital Assistant 7201 Case 7202 Display section 7203 Band 7204 Buckle 7205 Operation button 7206 Input / output terminal 7207 Icon 7250 Activity meter 7251 Case 7300 display device 7304 Display section 7350 Display device 7351 Lens 7351A Images 7351B Images 7352 Frame 7355 Tip 7360 Energy storage devices 7361 Positive lead 7362 Negative lead 7400 mobile phone 7401 Housing 7402 Display section 7403 Operation button 7404 External connection port 7405 Speaker 7406 Microphone 7407 Electricity storage devices 8000 display device 8001 Case 8002 Display section 8003 Speaker section 8004 Electricity storage devices 8021 Charging device 8022 cable 8024 Electricity storage device 8100 Lighting equipment 8101 Housing 8102 Light source 8103 Energy storage devices 8104 Ceiling 8105 Side wall 8106 beds 8107 Window 8200 indoor unit 8201 Housing 8202 Ventilation outlet 8203 Energy storage devices 8204 Outdoor unit 8300 Electric refrigerator-freezer 8301 Housing 8302 Refrigerator door 8303 Freezer door 8304 Energy storage devices 8400 Automobiles 8401 Headlight 8500 cars 9600 tablet device 9625 Switch 9626 Switch 9627 Power Switch 9628 Operation Switch 9629 Fasteners 9630 chassis 9631 Display section 9631a Display section 9631b Display section 9632a area 9632b area 9633 Solar Cells 9634 Charge / Discharge Control Circuit 9635 Electricity storage unit 9636 DC / DC Converter 9637 Converter 9638 Operation Key 9639 Button 9640 Moving parts

Claims

[Claim 1] a positive electrode, a negative electrode, a first separator, an electrolyte, and an outer casing; the positive electrode includes a positive electrode active material layer and a positive electrode current collector, the negative electrode includes a negative electrode active material layer and a negative electrode current collector, the first separator is located between the positive electrode and the negative electrode; the first separator includes polyphenylene sulfide or cellulose fibers; The electrolyte contains propylene carbonate, ethylene carbonate, vinylene carbonate, lithium hexafluorophosphate, and a lithium salt represented by the following general formula (G1): 【Chemical 1】 (In general formula (G1), R １ and R ２ each independently represents fluorine or a linear, branched or cyclic fluoroalkyl group having 1 to 10 carbon atoms.

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