Secondary battery

Abstract

To provide a secondary battery which is appropriate for a wearable device, and provide a novel power storage device.SOLUTION: A part of electrodes used for a secondary battery, more particularly, a collector and an active material layer are cut and processed to obtain a complex shape, and thus, an electrode far from a curvature center as compared with an electrode near the curvature center is curved, and thereby preventing a position of an end part from deviating from a position of the electrode near the curvature center, or softening a tension applied to the electrode far from the curvature center.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] One aspect of the present invention relates to a secondary battery and an electronic device including the secondary battery.

[0002] Note that one embodiment of the present invention is not limited to the above technical fields. The technical field of one aspect relates to an article, a method, or a manufacturing method. One aspect of the present invention is a process, machine, manufacture, or composition. Therefore, the invention disclosed herein more specifically relates to The technical field of one embodiment of the present invention is a semiconductor device, a display device, a light-emitting device, a power storage device, a memory device, Examples include their driving methods and their manufacturing methods.

[0003] In this specification, the term "electronic device" refers to any device that has a secondary battery. Electro-optical devices having a secondary battery, information terminal devices having a secondary battery, vehicles having a secondary battery, etc. It is an electronic device. [Background technology]

[0004] In recent years, display devices that are worn on the human body, such as head-mounted displays, have been proposed. These are called hard-mounted displays or wearable displays. Electronic devices that are worn on the human body (also called wearable devices), such as hearing aids, There is a demand for lighter and smaller vessels and other items.

[0005] Wearable devices and mobile information terminals are equipped with secondary batteries that can be repeatedly charged and discharged. Wearable devices and mobile information terminals are often equipped with electronic devices, and because of their light weight and small size, In addition, there is the problem that the operation time of wearable devices and mobile information terminals is limited. As a secondary battery to be installed in wearable devices and mobile information terminals, it is lightweight and small. It is required that the device can be used for a long period of time.

[0006] In addition, as electronic devices become lighter, the secondary batteries that supply power to these devices also need to become lighter. There is a demand for miniaturization.

[0007] In addition, electronic book readers equipped with flexible display devices are disclosed in Patent Documents 1 and 2. It has been disclosed. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Patent Publication No. 2010-282181 [Patent Document 2] Patent Publication No. 2010-282183 Summary of the Invention [Problem to be solved by the invention]

[0009] One of the objectives is to provide a secondary battery suitable for wearable devices. An object of the present invention is to provide a power storage device.

[0010] Alternatively, electronic devices with novel structures can be provided. Specifically, various external shapes can be provided. To provide an electronic device having a novel structure that can be used in various ways. Another object is to provide an electronic device having such a structure and a secondary battery having a shape suitable for the electronic device. .

[0011] The description of these problems does not preclude the existence of other problems. The embodiment does not necessarily have 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] When manufacturing and using a flexible secondary battery, or when manufacturing a curved secondary battery In this case, when multiple electrodes are bent, they are bent with different curvatures. In comparison, the electrode farther from the center of curvature is bent, and the position of the edge is shifted or pulled. At the end of the electrode, there is a part that electrically contacts the lead (also called an electrode tab). (It can be).

[0013] When manufacturing a thin secondary battery, the first electrode (positive electrode) and the active material layer are placed in the area surrounded by the exterior body. A plurality of combinations of the first electrode and the second electrode (negative electrode) are stacked. After the first electrodes are stacked together, ultrasonic welding or the like is performed to fix the ends. After the second electrodes are overlapped, ultrasonic welding or the like is performed to fix the ends of the second electrodes.

[0014] The more layers there are, the greater the capacitance and thickness. The electrode farther from the center of curvature than the pole is bent, causing the edge position to shift significantly, or Being pulled.

[0015] Therefore, by cutting a part of the electrode used in the secondary battery and making it into a complex shape, the center of curvature The electrode farther from the center of curvature is bent more than the electrode closer to the center of curvature, and the position of the edge is closer to the center of curvature. Prevents misalignment of the electrode or reduces tension applied to the electrode far from the center of curvature do.

[0016] Specifically, after forming an active material layer on a current collector, the active material layer is removed from the current collector in the irradiated area using a laser beam or the like. Laser processing is performed to remove a part of the active material layer. The openings, cuts and crevices that can be formed can be linear, geometric (polygonal, irregular, etc.), It may be circular. A plurality of openings or a plurality of cuts may be formed regularly, or it may be irregular. A plurality of openings or cuts may be formed in the rule. A secondary battery is made using electrodes with cuts in some parts. For example, alternating cuts ( To create a secondary battery with electrodes that have a shape with long cuts or jagged cuts .

[0017] Even if laser processing is performed on at least one or both of the positive and negative electrodes used in secondary batteries, good.

[0018] In the case of a bent secondary battery, the vertical relationship between the electrodes close to the center of curvature and those far from the center of curvature Since the distance is determined, the part of the electrode farthest from the center of curvature is cut by laser processing. The cutting process is performed so that the current collector does not split into two pieces. In the case of a distant electrode, a slit is provided to relieve the tension on the electrode. In the case of electrodes, cuts are provided to relieve the compressive force on the electrodes.

[0019] In addition, if the secondary battery is flexible, it can be bent in a certain direction so that it can be bent in either direction. In this case, at least the outermost electrodes (i.e., the positive electrode on the top layer and the positive electrode on the bottom layer) It is preferable to perform laser cutting on the positive electrode of the uppermost layer, the negative electrode of the uppermost layer, and the negative electrode of the lowermost layer. Desirable.

[0020] The flexible secondary battery is a secondary battery that can be partially bent multiple times. Bent secondary batteries are batteries that are bent once during the manufacturing process of being built into electronic devices. This refers to a secondary battery that is fixed in a mounted state.

[0021] In addition, the present invention is not limited to removing a part of the current collector and a part of the active material layer by laser processing. Cutting is done using cutting tools such as cutters and scissors, and cutting tools such as lathes and milling machines. Alternatively, a laser beam may be scanned over a portion of the current collector and a portion of the active material layer to perform cutting. Instead, a part of the current collector and a part of the active material layer are scanned with ultra-high pressure water. In addition, a part of the active material layer may be removed.

[0022] In addition, cuts or openings are formed in the current collector to form tension relief portions, but there are no particular limitations. Even if the film thickness is not fixed and a thin portion is provided locally to relieve the tension when the secondary battery is bent, In this case, the current collector has at least two different inclined surfaces, and a gap is formed between the two inclined surfaces. The angle between the two inclined surfaces is preferably 90° or more and less than 180°. The angle is preferably 120° or more and 170° or less. The area having a curved surface between the two inclined surfaces is The film has a shape that is thinner than other areas. Also, it has a structure that includes cuts, openings, and thin film portions. A current collector having a plurality of these may also be used.

[0023] If no tension-relieving portion is provided on the current collector, the secondary battery may crack due to the tension when bent. Scratches and cracks are formed, and repeated bending can cause the cracks and tears to expand, resulting in the current collector breaking (breaking). If the current collector is broken, the area where electricity flows will be reduced, and the current will flow in that area. The electric field may be concentrated, causing a short circuit or accelerating the deterioration of the secondary battery. The adhesion at the scratches or cracks (the adhesion at the interface between the current collector and the active material layer) decreases, and the battery is no longer usable as a secondary battery. may cause it to stop working. [Effects of the Invention]

[0024] Flexible or curved secondary batteries can be realized.

[0025] In addition, when a secondary battery is bent, the electrodes of the secondary battery are also bent, and part of the electrodes is cut off. This prevents the end of the electrode from being pulled and cracking the electrode. This can improve the reliability of a secondary battery that can be easily broken or bent. In addition, if the housing of an electronic device is made flexible, parts of the electronic device, including the battery, can be easily can bend everything. [Brief explanation of the drawings]

[0026] [Figure 1] 1A and 1B are a perspective view and a cross-sectional view illustrating one embodiment of the present invention. [Figure 2] 1A to 1C are a perspective view, a top view, and a cross-sectional view illustrating one embodiment of the present invention. [Figure 3] FIG. 1 is a plan view illustrating one embodiment of the present invention. [Figure 4] FIG. 1 is a perspective view illustrating one embodiment of the present invention. [Figure 5] FIG. 1 is a perspective view illustrating one embodiment of the present invention. [Figure 6] 1A and 1B are perspective views of an appearance of an electronic device and a secondary battery according to one embodiment of the present invention. [Figure 7] 1A and 1B are perspective views of an appearance of an electronic device and a secondary battery according to one embodiment of the present invention. [Figure 8] 1A and 1B are a plan view and a cross-sectional view of an electronic device. [Figure 9] FIG. 1 is a perspective view of an external appearance of an electronic device. [Figure 10] FIG. 1 is a diagram illustrating a vehicle having a secondary battery. [Figure 11] FIG. 10 is a diagram illustrating the radius of curvature of a surface. [Figure 12] FIG. 10 is a diagram illustrating a center of curvature. [Figure 13] (A) is a plan view of the positive electrode, and (B) is a plan view of the negative electrode. [Figure 14] This is an X-ray CT image of the sample. [Figure 15] The photographs show the external appearance, an X-ray CT image of the sample, and an observation photograph of the extracted electrode. [Figure 16] The figures show an X-ray CT image, a photograph of the external appearance, and charge / discharge characteristics of the sample. [Figure 17] FIG. 2 is a graph showing charge and discharge characteristics. DETAILED DESCRIPTION OF THE INVENTION

[0027] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The present invention is not limited to the following description, and various modifications in form and details are possible by those skilled in the art. Furthermore, the present invention should not be construed as being limited to the description of the following embodiments. It is not something that can be done.

[0028] (Embodiment 1) In this embodiment, a current collector having a plurality of cuts is used, and an air filter is attached to a film as an outer casing. An example of manufacturing a lithium-ion secondary battery using a film with a pattern created by embossing. Shows.

[0029] First, a sheet made of a flexible substrate is prepared. The sheet is a laminate, and the metal film is The adhesive layer (also called a heat seal layer) is used on one or both sides. The adhesive layer is a heat-sealable resin film containing polypropylene, polyethylene, etc. In this embodiment, the sheet has a nylon resin on the surface of an aluminum foil, The back of the foil is made of acid-resistant polypropylene film and the metal foil is laminated with polypropylene film. Use a sheet.

[0030] This sheet is cut to prepare film, which is then embossed to create bumps on the film. In this embodiment, the pattern is formed by providing projections and depressions on both sides of the film. As shown in FIG. 1(A), if it is rectangular, it is folded in the center of the film 11. The structure is such that two sides of the package overlap and three sides are sealed with an adhesive layer.

[0031] In order to manufacture a bendable secondary battery or a bent secondary battery, a film that serves as an exterior body is It is preferable that the film etc. have a structure that can relieve distortion caused by stress. The recesses or protrusions of the mold are formed by press working, for example, embossing.

[0032] Embossing is a type of press processing in which an embossing roll with an uneven surface is used to fill the This is a process in which the film is pressed against an embossing roll to form irregularities on the film that correspond to the irregularities of the embossing roll. An embossing roll is a roll with a pattern engraved on its surface.

[0033] The recesses or protrusions formed in the film by embossing allow the film to adhere to the wall of the sealing structure. The volume of the space that is a part of the film is variable, forming a closed space. It can also be said that the convex parts are formed as bellows or bellows structures. Not only can it be embossed, but it can also create relief on a part of the film. It's fine as long as it's a method.

[0034] There are various types of secondary battery structures, but the structure in which the exterior body is made of film is used. The film used for the exterior is a metal film (aluminum, stainless steel, nickel steel, etc.). Plastic films made of organic materials, organic materials (organic resins, fibers, etc.) and inorganic materials Hybrid material films containing materials (such as ceramics), carbon-containing films (carbon a single layer film selected from the group consisting of a polyimide film, a graphite film, etc. The metal film is easy to emboss, and the embossing process is When recesses or protrusions are formed by the process, the surface area of ​​the film exposed to the outside air increases. It has excellent heat dissipation effect.

[0035] In the above configuration, the exterior body of the secondary battery has a curvature radius of 10 mm or more, preferably a curvature radius of 30 mm or more. The exterior of the secondary battery can be deformed within a range of 150 mm or more and a radius of curvature of 150 mm or less. The film used is made up of one or two sheets, and the sealing structure uses laminated film. If the battery is a laminated secondary battery, it is necessary to bend it to reduce the cross-sectional shape of the battery. If the shape is an arc, the structure will be sandwiched between two curved surfaces of the film.

[0036] The radius of curvature of a surface will be explained with reference to FIG. 11. In FIG. 11(A), a curved surface 1700 On a plane 1701 that cuts the surface 1700, a part of a curve 1702 included in the surface 1700 is cut by an arc of a circle. The radius of the circle is the radius of curvature 1703, and the center of the circle is the center of curvature 1704. FIG. 11(B) shows a top view of the curved surface 1700. FIG. 11(C) shows the curved surface 1700 on a plane 1701. When cutting a curved surface with a plane, the angle of the plane to the curved surface and The radius of curvature of the curve that appears in the cross section varies depending on the cutting position. Now, the smallest radius of curvature is taken as the radius of curvature of the surface.

[0037] When a secondary battery with two films sandwiching electrodes, electrolyte, etc., is bent, In this case, the radius of curvature 1802 of the film 1801 on the side closer to the center of curvature 1800 of the secondary battery is , which is smaller than the radius of curvature 1804 of the film 1803 on the side farther from the center of curvature 1800 (Fig. 12(A)). When the secondary battery is bent to make the cross section arc-shaped, the field close to the center of curvature 180° The surface of the film is subjected to compressive stress, while the surface of the film far from the center of curvature 180° is subjected to tensile stress. The stress is applied to the surface of the exterior body (Fig. 12(B)). When this structure is formed, even if compressive stress or tensile stress is applied, the influence of strain is minimized. Therefore, the secondary battery can be prevented from being damaged by the external force of the exterior body on the side closer to the center of curvature. The deformation can be carried out within a range in which the radius of curvature is 10 mm or more, preferably 30 mm or more.

[0038] The cross-sectional shape of the secondary battery is not limited to a simple arc shape, and may be a shape having a partial arc. For example, the shape shown in FIG. 12(C), a wave shape (FIG. 12(D)), an S-shape, etc. In the case where the curved surface of the secondary battery has a shape having a plurality of centers of curvature, The curvature radius at each center of curvature of the surface with the smallest curvature radius is The radius of curvature of the outer casing closest to the center of curvature is 10 mm or more, preferably 30 mm or more. The secondary battery can be deformed within the above range.

[0039] When a secondary battery with two films as the exterior body and an electrolyte sandwiched between them is bent, The radius of curvature of the film is smaller than the radius of curvature of the second film. The pattern on the first film is different from the pattern on the second film. When the film is curved, compressive stress is applied to the film surface near the center of curvature, and compressive stress is applied to the film surface far from the center of curvature. The surface is subjected to tensile stress. Even if compressive stress or tensile stress is applied, The exterior has a pattern formed by concave or convex parts, so the influence of distortion is within the allowable range. can be kept within the limits.

[0040] Next, as shown in FIG. 1(B), a positive electrode current collector 12, a separator 13, and a negative electrode current collector 14 that constitute the secondary battery are assembled. A stack of electrode current collectors 14 is prepared.

[0041] The current collectors such as the positive electrode current collector 12 and the negative electrode current collector 14 may be made of stainless steel, gold, platinum, zinc, Metals such as iron, nickel, copper, aluminum, titanium, tantalum, and their alloys, A material that is highly conductive and does not alloy with carrier ions such as lithium can be used. In addition, the heat resistance of silicon, titanium, neodymium, scandium, molybdenum, etc. has been improved. Aluminum alloys containing elements that react with silicon can be used. It may be formed from a metal element that forms silicide, which reacts with silicon to form silicide. The metal elements that are used include zirconium, titanium, hafnium, vanadium, niobium, and titanium. talc, chromium, molybdenum, tungsten, cobalt, nickel, etc. Also, current collectors The shape of the material can be foil, plate (sheet), punched metal, expanded metal, etc. The current collector may be used with a thickness of 5 μm or more and 30 μm or less. For the sake of simplicity, the positive electrode current collector 12, the separator 13, and the negative electrode current collector An example was shown in which a combination of 14 layers was combined into one and stored in an area enclosed by an exterior body. In order to increase the capacity of the secondary battery, multiple combinations are stacked and stored in an area enclosed by an exterior body. It is preferable that

[0042] As shown in FIG. 1(B), the positive electrode current collector 12 has a shape with a plurality of cuts 21.

[0043] By forming the positive electrode current collector 12 in a shape having a plurality of cuts 21, the positive electrode current collector The body 12 is expanded as a whole. Therefore, the positional deviation of the end portion can be reduced. When the positive electrode current collector 12 is twisted, a part of the positive electrode current collector 12 is twisted, i.e., has a curved portion. Therefore, the positive electrode current collector 12 can also be said to be a current collector having different inclined surfaces. The current collector 12 can also be referred to as a current collector having a gap or opening between the two inclined surfaces. The positive electrode current collector 12 can also be said to be a current collector having a curved surface between two inclined surfaces. do.

[0044] The laser light source for the laser processing to form the plurality of cuts 21 in the positive electrode current collector 12 is an oscillating laser. An ML-7320DL (manufactured by Miyachi Technos Co., Ltd.) with a length of approximately 1065 nm can be used. The laser light source is used to irradiate a laser beam, and the stage is moved to perform scanning with the laser beam.

[0045] In addition, after forming an active material layer on one or both surfaces of the positive electrode current collector 12, laser processing may be performed. The cut surface formed by irradiating the laser beam is given strong energy and is used for current collection. This is desirable because the body and the active material layer are firmly fixed together.

[0046] Next, the lead electrodes 16a and 16b having the sealing layer 15 shown in FIG. The lead electrodes 16a and 16b are also called lead terminals, and are The lead electrode 16a is provided to lead out the positive or negative electrode of the battery to the outside of the exterior film. The lead electrode 16a is electrically connected to the positive electrode. The lead electrode 16b can be made of a material that can be used for a negative electrode. The lead electrode 16b is made of a material such as copper, which can be used for the negative electrode current collector. Any material that can be used can be used.

[0047] One lead electrode and the protruding portion of the positive electrode current collector 12 are electrically connected by ultrasonic welding or the like. In addition, the other lead electrode and the protruding portion of the negative electrode current collector 14 are connected by ultrasonic welding or the like. Make an electrical connection.

[0048] Then, two sides of the film 11 are heat-pressed to leave one side for the electrolyte. During the thermocompression bonding, the sealing layer 15 provided on the lead terminal also melts, forming a seal between the lead terminal and the The film 11 is fixed between the film 11 and the substrate 10. Then, the desired A quantity of electrolyte is dropped onto the inside of the bag-shaped film 11. Finally, the film is heat-pressed. The remaining edge of the film is sealed by thermocompression bonding.

[0049] In this way, the secondary battery 40 shown in FIG. 1(D) can be fabricated.

[0050] FIG. 1(E) shows an example of a cross section taken along the chain line AB in FIG. 1(D).

[0051] As shown in FIG. 1(E), the unevenness of the film 11 is formed in the area overlapping with the positive electrode current collector 12 and in the area overlapping with the positive electrode current collector 12 by heat and pressure. As shown in FIG. 1(E), the positive electrode current collector 12, the positive electrode active material layer 1 8, separator 13, negative electrode active material layer 19, and negative electrode current collector 14 are laminated in this order. The film is sandwiched between the bent films 11 and further sealed at the edges with adhesive layers 30. The space contains an electrolyte 20 .

[0052] The positive electrode current collector 12 of the obtained secondary battery 40 has a cut, and when bent as shown in FIG. 2A shows a schematic cross-sectional view (longitudinal cross-sectional view) of the secondary battery 40 in this state. The positive electrode current collector 12, the separator 13, and the negative electrode current collector 14 arranged inside the film are stacked. FIG. 2 is a perspective view showing the positional relationship of layers.

[0053] FIG. 2(C) is a schematic cross-sectional view taken along the chain line X-X' in FIG. 2(B), which is a top view. As shown in Figure 2(C), when the secondary battery is bent, different inclinations appear on either side of the cut. In this way, a positive electrode current collector 12 having a cut is disposed. The body 12 can change its shape, and when bent, it partially deforms to bend the secondary battery. In Figure 2(C), the cross section taken along the chain line X-X' Since there are two gaps, the first inclined surface and the second inclined surface form an angle β1. The third inclined surface forms an angle β2. The angle β1 or the angle β2 is greater than or equal to 90° and less than 180°. In FIG. 2(C), the angle of curvature is 120° or more and 170° or less. Although an example is shown, even when bending in the opposite direction, the first inclined surface and the second inclined surface have an angle. As shown in FIG. 2(C), the positive electrode active material layer 18 also has a gap. When a flexible binder is used, the positive electrode active material layer 18 does not have any cuts. That's fine.

[0054] The positive electrode active material used in the positive electrode active material layer 18 may have an olivine type crystal structure, a layered rock salt type crystal structure, or the like. Examples of the positive electrode active material include composite oxides having a crystalline structure or a spinel-type crystalline structure. For example, LiFeO2, LiCoO2, LiNiO2, LiMn2O4, V2O5, Cr2 Compounds such as O5 and MnO2 are used.

[0055] Alternatively, a composite material (general formula LiMPO4, where M is Fe(II), Mn(II), Co(II) Representative examples of the general formula LiMPO4 include: Examples include LiFePO4, LiNiPO4, LiCoPO4, LiMnPO4, and LiFe a Ni b PO4, LiFe a Co b PO4, LiFe a Mn b PO4, LiNi a Co b PO4, LiNi a Mn b PO4(a+b is less than 1, 0 <a<1、0<b<1)、LiF e c Ni d Co e PO4, LiFe c Ni d Mn e PO4, LiNi c Co d Mn e PO 4(c+d+e is 1 or less, 0 <c<1、0<d<1、0<e<1)、LiFe f Ni g C o hMn i PO4 (where f + g + h + i is less than or equal to 1, 0 < f < 1, 0 < g < 1, 0 < h < 1, 0 <i < 1), etc. Lithium compounds can be used as materials.

[0056] Or, composite materials such as the general formula Li (2-j) MSiO4 (M is one or more of Fe(II), Mn(II), Co( II), Ni(II), 0 ≦ j ≦ 2), etc. can be used. General Formula Li (2-j) Representative examples of MSiO4 include Li (2-j) FeSiO4, Li (2 -j) NiSiO4, Li (2-j) CoSiO4, Li (2-j) MnSiO4, Li (2-j) Fe k Ni l SiO4, Li (2-j) Fe k Co l SiO4, Li (2-j ) Fe k Mn l SiO4, Li (2-j) Ni k Co l SiO4, Li (2-j) Ni k Mn l SiO4 (where k + l is less than or equal to 1, 0 < k < 1, 0 < l < 1), Li (2-j) Fe m N i n Co q SiO4, Li (2-j) Fe m Ni n Mn q SiO4, Li (2-j) Ni m Co n Mn q SiO4 (where m + n + q is less than or equal to 1, 0 < m < 1, 0 < n < 1, 0 < q < 1) , Li (2-j) Fer 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 and so on.

[0057] Also, as the positive electrode active material, A x M2(XO4)3 (A = Li, Na, Mg, M = Fe, M n, Ti, V, Nb, Al, X = S, P, Mo, W, As, Si), and the general formula of the nasi cobalt-type compound can be used. As the nasiocobalt-type compound, Fe2(MnO4) 3, Fe2(SO4)3, Li3Fe2(PO4)3, etc. are available. Also, as the positive electrode active material , compounds represented by the general formula of Li2MPO4F, Li2MP2O7, Li5MO4 (M = Fe, Mn) , perovskite-type fluorides such as NaFeF3, FeF3, metal chalcogenides (sulfides, selenides, tellurides) such as TiS2, Mo S2, oxides having a reverse spinel-type crystal structure such as LiMVO4, vanadium oxide-based (V2O5, V6O , L 13 , iV3O8, etc.), manganese oxides, organic sulfur compounds, etc. can be used as materials. When the carrier ion is an alkali metal ion other than lithium ion or an alkaline earth metal ion

[0058] , as the positive electrode active material, instead of lithium, an alkali metal (e.g., sodium lithium, potassium, etc.), an alkaline earth metal (e.g., calcium, strontium, barium ium, beryllium, magnesium, etc.) can be used. As the separator 13, cellulose (paper) or polypropylene provided with pores can be used.

[0059] ​An insulator such as polyethylene can be used.

[0060] The electrolytic solution uses a material having carrier ions as an electrolyte. Typical examples of the electrolyte include: LiPF6, LiClO4, LiAsF6, LiBF4, LiCF3SO3, Li( These include lithium salts such as Li(CF3SO2)2N and Li(C2F5SO2)2N. The materials may be used singly or in any combination and ratio of two or more. .

[0061] In addition, the carrier ions are alkali metal ions other than lithium ions, alkaline earth metal ions, etc. In the case of metal ions, the electrolyte is an alkali metal ion instead of lithium in the above lithium salt. alkali metals (e.g., sodium and potassium), alkaline earth metals (e.g., calcium, Strontium, barium, beryllium, magnesium, etc.) may also be used.

[0062] The solvent of the electrolyte solution is a material in which carrier ions can move. As the solvent, an aprotic organic solvent is preferred. Representative examples of the aprotic organic solvent include: Ethylene carbonate (EC), propylene carbonate, dimethyl carbonate, diene Dimethyl carbonate (DEC), ethyl methyl carbonate (EMC), gamma-butyrolactone acetonitrile, dimethoxyethane, tetrahydrofuran, etc. Alternatively, a polymer material that can be gelled as a solvent for the electrolyte may be used. By adding a polymeric material to the electrolyte to make it gel, safety against leakage etc. can be improved. In addition, it is possible to make the storage battery thinner and lighter. Examples include silicone gel, acrylic gel, acrylonitrile gel, and polyethylene glycol. oxide, polypropylene oxide, fluorine-based polymer, etc. Also, the solvent of the electrolyte As the liquid, one or more ionic liquids (room temperature molten salts) that are flame-retardant and non-volatile are used. Therefore, even if the internal temperature of the battery rises due to an internal short circuit or overcharging, the battery will not explode or explode. It can prevent fires and other accidents. Ionic liquids are salts in a fluid state, and ions can move freely. Ionic liquids have high conductivity. Ionic liquids contain cations and anions. Examples include ionic liquids containing the ethylmethylimidazolium (EMI) cation, or N- Methyl-N-propylpiperidinium (PP 13 ) cation-containing ionic liquids .

[0063] In addition, instead of the electrolyte solution, solid electrolytes containing inorganic materials such as sulfides and oxides, and P A solid electrolyte containing a polymer material such as EO (polyethylene oxide) can be used. When a solid electrolyte is used, there is no need to install a separator or spacer. Since the entire pond can be solidified, there is no risk of leakage, dramatically improving safety.

[0064] The negative electrode active material of the negative electrode active material layer 19 may be formed by dissolving and depositing lithium or by depositing lithium ions. Materials that can react reversibly with ions can be used, such as lithium metal, carbon-based materials, and alloys. A gold-based material or the like can be used.

[0065] Lithium metal has a low oxidation-reduction potential (-3.045 V vs. the standard hydrogen electrode) and is lightweight and and high specific capacity per volume (3860mAh / g and 2062mAh / cm, respectively) 3 ) and is therefore preferable.

[0066] Carbon materials include graphite, easily graphitizable carbon (soft carbon), and non-graphitizable carbon (hard carbon). Examples include carbon nanotubes, graphene, and carbon black.

[0067] Graphite includes mesocarbon microbeads (MCMB), coke-based artificial graphite, and pitch. These include artificial graphite such as spheroidized artificial graphite, and natural graphite such as spheroidized natural graphite.

[0068] When lithium ions are inserted into graphite (when lithium-graphite intercalation compounds are formed), It exhibits a potential as low as that of lithium metal (0.1 to 0.3 V vs. Li / Li + ).child This allows lithium-ion secondary batteries to exhibit high operating voltages. , relatively high capacity per unit volume, small volume expansion, inexpensive, and comparable to lithium metal This is preferable because it has advantages such as higher safety compared to the conventional method.

[0069] As a negative electrode active material, it is possible to carry out charge-discharge reactions by alloying and dealloying reactions with lithium. When the carrier ion is a lithium ion, for example, For example, Al, Si, Ge, Sn, Pb, Sb, Bi, Ag, Au, Zn, Cd, In, G There are materials that contain at least one of the elements a, etc. Such elements have a large capacity compared to carbon. Silicon, in particular, has a dramatically high theoretical capacity of 4200mAh / g. It is preferable to use silicon as the material. Examples of materials using such elements include: SiO, Mg2Si, Mg2Ge, SnO, SnO2, Mg2Sn, SnS2, V2Sn 3, FeSn2, CoSn2, Ni3Sn2, Cu6Sn5, Ag3Sn, Ag3Sb, Ni2MnSb, CeSb3, LaSn3, La3Co2Sn7, CoSb3, InSb , SbSn, etc. SiO is a powder of silicon oxide containing silicon-rich parts. SiO y (2>y>0). For example, SiO can be expressed as Si2O3, Materials containing one or more selected from Si3O4 or SiO2, or Si powder and It also contains mixtures of silicon oxide, SiO2. SiO also contains other elements (carbon, nitrogen, iron, aluminum, etc.). It may also contain other metals such as ammonium, copper, titanium, calcium, and manganese. , amorphous Si, polycrystalline Si, Si2O3, Si3O4, Si2O, SiO2 It refers to a material containing multiple SiO2 particles, and SiO2 is a colored material. x (X is 2 or more), it is colorless, transparent, or white, and can be distinguished. After producing a secondary battery using SiO as a material, the battery can be made to have a high energy density by repeatedly charging and discharging it. Therefore, when SiO is oxidized, it may be transformed into SiO2.

[0070] In addition, titanium dioxide (TiO2) and lithium titanium oxide (Li4T i5O 12 ), lithium-graphite intercalation compound, (Li x C6), niobium pentoxide (Nb2O5 ), tungsten oxide (WO2), molybdenum oxide (MoO2), etc. can be done.

[0071] In addition, the negative electrode active material is a nitride of lithium and transition metals, which has a Li3N structure. i 3-x M x N (M=Co, Ni, Cu) can be used. For example, Li 2.6 C o 0.4N3 has a large charge / discharge capacity (900mAh / g, 1890mAh / cm 3 ) indicates preferable.

[0072] When a nitride of lithium and a transition metal is used, the negative electrode active material contains lithium ions, so the positive electrode Combine with materials such as V2O5 and Cr3O8 that do not contain lithium ions as electrode active materials 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, it becomes the negative electrode active material. Nitrides of lithium and transition metals can be used.

[0073] 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 This also occurs with fluorides such as those mentioned above. Since the potential of the fluorides is high, they are not suitable for use as positive electrode active materials. That's fine.

[0074] In addition to the above-mentioned negative electrode active material, the negative electrode active material layer 19 contains a material for improving the adhesion of the active material. The negative electrode active material layer 19 may contain a binder, a conductive additive for increasing the conductivity of the negative electrode active material layer 19, and the like. stomach.

[0075] The secondary battery is configured such that, for example, the thickness of the separator 13 is about 25 μm, the positive electrode current collector 12 is about 1 10 μm or more and about 40 μm or less, the positive electrode active material layer 18 is about 100 μm, and the negative electrode active material layer 19 is about 1 The thickness of the film 11 is about 8 μm or more and about 40 μm or less. The embossing depth on the film 11 is about 500 μm. When the embossing depth of the film 11 is 2 mm or more, the thickness of the entire secondary battery The embossing depth should be 1 mm or less, preferably 500 μm or less, because the thickness of the surface will be too thick. Although the adhesive layer 30 is only partially shown in FIG. 1(E), the film has a polyimide film. A layer made of polypropylene is provided on the surface of the film 11, and only the thermocompression bonded portion is an adhesive layer 3 The result is 0.

[0076] Also, FIG. 1(E) shows an example in which the lower side of the film 11 is fixed and pressed. In this case, the upper side is bent significantly, forming a step, so that the area between the folded film 11 When multiple combinations of the above laminations are provided, for example, eight or more, the step becomes large. Therefore, there is a risk that too much stress will be applied to the upper film 11. In this case, the positional misalignment between the end face of the film and the end face of the lower film may become large. To prevent misalignment, a step is also provided on the lower film, and the center is It may be configured to be crimped with.

[0077] The obtained secondary battery 40 has a pattern with projections and depressions on the film 11 that serves as the exterior body. The area between the dotted line and the end face in FIG. 1(D) is the thermocompression bonding area 17, and there is also a recess in that area. The unevenness of the thermocompression bonded area 17 is smaller than that of the central part, but the secondary battery This can reduce the stress that is applied when the cable is bent.

[0078] Here, the flow of current during charging of a secondary battery will be explained using Figure 1(F). When a secondary battery is considered as a closed circuit, the movement of lithium ions and the flow of current are in the same direction. In secondary batteries that use lithium, the anode (positive electrode) and cathode (cathode) is switched, and the oxidation reaction and reduction reaction are switched, so the reaction potential The electrode with a higher reaction potential is called the positive electrode, and the electrode with a lower reaction potential is called the negative electrode. Whether charging, discharging, or applying a reverse pulse current, Even when an electric current flows through it, the positive electrode is called the "positive electrode" or "+ electrode (plus electrode)" and the negative electrode is called the "positive electrode" or "+ electrode (plus electrode)". This is called the "negative electrode" or "-electrode (minus electrode)." When using the terms anode (positive electrode) and cathode (negative electrode), the following occurs during charging and discharging: This can be confusing as the anode and cathode are opposites. The term "cathode" will not be used in this specification. When using the terms cathode and positive electrode, specify whether they are charging or discharging. It will also be noted whether it corresponds to the negative pole (negative pole) or the positive pole (positive pole).

[0079] A charger is connected to the two terminals shown in FIG. 1(F), and the secondary battery 40 is charged. As the charging of the battery 40 progresses, the potential difference between the electrodes increases. The current flows from the external terminal toward the positive electrode current collector 12, and then flows through the positive electrode current collector 12 in the secondary battery 40. 2 to the negative electrode current collector 14, and from the negative electrode current collector 14 to the external terminal of the secondary battery 40. The direction of the current flowing is considered to be the positive direction. In other words, the direction of the charging current is considered to be the current direction. is doing.

[0080] The position and size of the cut are not particularly limited. For example, as shown in FIG. 3(B), Alternatively, the positive electrode current collector 12b shown in FIG. 3(C) may be used. In the case of the positive electrode current collector 12b shown in FIG. 3(C), the direction of the cut is different from that in FIG. 2(B). Therefore, it is possible to bend it in a direction different from the direction bent in FIG. 2(B). As shown in (A), the positive electrode current collector 12a may have a plurality of slit-like openings 27. Alternatively, as shown in FIG. 3(D), a positive electrode current collector 12d having a plurality of rectangular openings 27 may be used. Also, the positive electrode current collector may have a combination of openings and slits. As shown in E), a positive electrode current collector 12e having a meandering portion on the upper surface of the positive electrode current collector, As shown in FIG. 3(F), a positive electrode current collector 12f has an upper surface shape with a plurality of meandering portions. It may also be possible to use the following.

[0081] In this embodiment, an example in which cuts are made in the positive electrode current collector 12 and the positive electrode active material layer 18 is shown. However, there is no particular limitation, and cuts may be made in the negative electrode current collector 14 and the negative electrode active material layer 19. In addition, the cut line of the positive electrode current collector 12 and the cut line of the negative electrode current collector 14 may be different. For example, the number of cuts in the current collector on the side where the secondary battery is bent and deformed greatly is increased compared to the other side. By doing so, the effect of alleviating stress can be further obtained.

[0082] For ease of understanding, the secondary battery 40 shown in FIG. 1(E) has one positive electrode current collector and one Although the explanation has been given using one separator and one negative electrode current collector, in reality, multiple positive electrode current collectors and For example, as shown in FIG. 4(B), a positive electrode current collector 12 and a separator Eight combinations of anode current collector 13 and cathode current collector 14 were used, and they were wrapped in an exterior film. The positive electrode current collector 12 is provided with a positive electrode active material layer on one side thereof. , one separator is folded and the positive electrode current collector 12 is sandwiched between the folded separator. B) has 16 separators, i.e. 8 sheets are folded, but if used without folding, The separator may be 15. The separator may be bag-shaped. The thickness of the secondary battery 40 When the thickness is to be reduced, the positive electrode current collector 12, the separator 13, and the negative electrode current collector 14 are separated as shown in FIG. In FIG. 4(A), a second separator is further stacked. However, the second separator can be omitted.

[0083] In addition, when coating one side of the current collector with an active material, as shown in Figure 4(C), The surfaces of the negative electrode current collector that are not coated with the positive electrode active material are also coated with the negative electrode active material. By stacking the current collectors in this order, the separator This is preferable because it can reduce the number of data by half.

[0084] 5 shows a perspective view of two combinations. In this example, a cathode active material layer is provided on the surface of the cathode current collector 14. a positive electrode active material layer, a separator 13, a positive electrode current collector 12, a positive electrode active material layer, a separator, a negative The electrode active material layer and the negative electrode current collector are arranged in this order. The surface has a plurality of cuts in a geometric pattern formed by laser processing. It refers to patterns including stripes, checkered patterns, meander patterns, etc. Although two separators are shown in the figure, it is also possible to fold one separator and It is also possible to use a structure in which the positive electrode current collector 12 is housed between the two bent surfaces. The data may be in the form of a bag.

[0085] It is also possible to provide a negative electrode active material layer on both sides of the negative electrode current collector. A negative electrode current collector with a negative electrode active material layer on only one side is placed between two negative electrode current collectors with a negative electrode active material layer on both sides. Three negative electrode current collectors, four positive electrode current collectors with positive electrode active material layers on both sides, and eight separators This shows an example of a secondary battery with a capacitor sandwiched between them.

[0086] In this embodiment, an example of a small battery used in a portable information terminal or the like is shown, but there is no particular limitation. The present invention can be applied not only to batteries but also to large batteries to be installed in vehicles, etc.

[0087] In this embodiment, an example in which the present invention is applied to a lithium ion secondary battery is shown. One embodiment of the present invention is not limited to this. Various secondary batteries, for example, lead acid batteries, lithium ion batteries, Polymer secondary battery, nickel-metal hydride battery, nickel-cadmium battery, nickel- Suitable for iron batteries, nickel-zinc batteries, silver oxide-zinc batteries, solid-state batteries, air batteries, etc. Alternatively, the present invention can be applied to various power storage devices, for example. It can also be applied to primary batteries, capacitors, lithium ion capacitors, etc. Furthermore, solar cells, optical sensors, touch sensors, display devices, FPCs (flexible print Substrate), optical film (polarizing plate, retardation plate, prism sheet, light reflection sheet, light diffusion sheet It is also possible to apply this to other applications such as

[0088] (Embodiment 2) In this embodiment, a lithium ion secondary battery obtained by using the first embodiment is incorporated. An example of an electronic device is shown.

[0089] The secondary battery obtained using the first embodiment has a thin, flexible film exterior. , and attached to a support structure having a curved surface, and attached to the curved surface portion of the support structure in an area with a large radius of curvature. It can be transformed accordingly.

[0090] As an example of an electronic device that uses a flexible power storage device, there is a head-mounted Display devices such as TVs, tablet displays, and goggle displays receiver), desktop or notebook personal computers, monitors, digital cameras, digital video cameras, digital photo frames, Electronic notebooks, electronic book terminals, electronic translators, toys, voice input devices such as microphones, electric Electric appliances such as microwave ovens, electric toothbrushes, microwave ovens, electric rice cookers, electric washing machines, Vacuum cleaners, water heaters, electric fans, hair dryers, humidifiers, dehumidifiers, air conditioners, etc. Japanese-style facilities, dishwasher, dish dryer, clothes dryer, futon dryer, electric refrigerator, electric freezer, Electric refrigerators and freezers, DNA storage freezers, flashlights, power tools, smoke detectors, gas alarms, etc. Alarm devices such as burglar alarms, industrial robots, hearing aids, cardiac pacemakers, X-ray equipment , radiation measuring devices, health and medical equipment such as electric massagers and dialysis machines, mobile phones (mobile phones mobile phones, portable game machines, personal digital assistants, lighting devices, headphones Computers, stereos, remote controls, clocks such as table clocks and wall clocks, cordless phones Portable or stationary devices such as handsets, transceivers, pedometers, calculators, and digital audio players Examples include audio playback devices, pachinko machines, and other large game machines.

[0091] In addition, the flexible energy storage device can be attached to the interior or exterior walls of houses or buildings, or to automobiles. It can also be incorporated into curved surfaces of the interior or exterior of a vehicle.

[0092] FIG. 6A 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.

[0093] FIG. 6B 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 bent power storage device 7407 is also bent as shown in FIG. The power storage device 7407 is a laminated storage battery (also called a film-covered battery). The power storage device 7407 is fixed in a bent state. The lead electrode 7408 is electrically connected to the current collector 7409. The film on the exterior of the device 7407 is embossed, and a current collector with a cut is attached. This structure provides high reliability even when the power storage device 7407 is bent.

[0094] FIG. 6D shows an example of a bangle-type mobile phone. The mobile phone 7100 has a housing 7101, a display unit 7102, operation buttons 7103, and a power storage device 7104. FIG. 6E illustrates a bendable power storage device 7104. When the device is bent and worn on the user's arm, the housing may deform and cause damage to part or all of the power storage device 7104. The total curvature changes. Specifically, the curvature radius is between 10 mm and 150 mm. The main surface of the housing or the power storage device 7104 is partially or entirely changed. 104 has a lead electrode 7105 electrically connected to a current collector 7106. For example, The film of the exterior body of the power storage device 7104 is subjected to press processing to form a plurality of concaves and convexes. The curvature of the power storage device 7104 can be changed by using a current collector having a cut, and the number of times the power storage device 7104 can be bent is increased. The configuration is such that high reliability can be maintained at most.

[0095] FIG. 7(A) shows an example of a vacuum cleaner. By equipping the vacuum cleaner with a secondary battery, it can be made cordless. The inside of the vacuum cleaner has a dust collection space to absorb and store the dust. The space occupied by the power storage device 7604 is preferably as small as possible. Disposing a bendable power storage device 7604 between the outer surface and the dust collection space The vacuum cleaner 7600 includes an operation button 7603 and a power storage device 7604. FIG. 7B shows a bendable power storage device 7604. 4 has an embossed outer film, and uses a current collector with cuts to prevent storage. The power storage device 7604 has a highly reliable structure even when bent. The lead electrode 7601 is electrically connected to the negative electrode, and the lead electrode 7602 is electrically connected to the positive electrode. It has pole 7602.

[0096] In addition, another example of the power storage device 7604 has two lead electrodes exposed on one short side of the exterior body. As an example, FIG. 7C illustrates a bendable power storage device 7605. 605 is a structure in which a current collector or a lead electrode is exposed on each of the two short sides of the exterior body. do.

[0097] 7D shows an example of an internal structure of the power storage device 7605. The battery is composed of a positive electrode current collector 12, a separator 13, and two negative electrode current collectors 14. The electrode current collector 14 has a cut, and the cut is perpendicular to the bending direction of the power storage device 7605. The separator 13 is folded, and the positive electrode current collector 1 is inserted between the folded portions. 2. In addition, both surfaces of the positive electrode current collector 12 have positive electrode active material layers.

[0098] In addition, one of the electronic devices incorporating the lithium ion secondary battery obtained by using the first embodiment is Examples are shown in Figures 8 and 9.

[0099] The electronic device 7700 has a bendable display portion 7702, as shown in FIG. 7 shows a plan view of the electronic device 7700 with the display portion 7702 open. 8B, a power storage device 7704 is provided inside the display unit. The external perspective view of the 7702 in an open state corresponds to FIG. 9(A).

[0100] In addition, hinges 7701 and 7703 are provided for folding, and the display portion 7702 , an active matrix display device having an organic EL element on a plastic substrate, For example, the flexible display panel includes a transistor having an oxide semiconductor layer, The transistor and the organic EL element are electrically connected, and the transistor and the organic EL element are The electronic device shown in Figures 8 and 9 is placed between two plastic substrates. It can be made smaller by bending it at the part where jigs 7701 and 7703 are provided. This is an example of an electronic device 7700.

[0101] The cross-sectional view of the folded state is shown in FIG. 8(C), and its perspective view is shown in FIG. 9(B). Although an example of folding at two points using two hinges 7701 and 7703 has been shown, there is no particular limitation. By increasing the size of the display unit 7702 and increasing the number of hinges, it is possible to fold the display unit in three or more places. The electronic device may be folded at one location using one hinge. You may do so.

[0102] In addition, the materials (silicon rubber and plastic materials) for the housing of the electronic device 7700 are selected and If the housing is flexible, the power storage device 7704 provided therein can be bent. The child device 7700 may be bent in whole or in part.

[0103] In addition, if a bendable power storage device is installed in a vehicle, it will be possible to use it in hybrid vehicles (HEVs), electric vehicles (EVs), and other vehicles. Next-generation clean energy vehicles such as electric vehicles (EV) and plug-in hybrid vehicles (PHEV) It can also be used for agricultural machinery and motorized bicycles, including electrically assisted bicycles. , motorcycles, electric wheelchairs, electric carts, small or large boats, submarines, fixed-wing aircraft and rotary-wing aircraft It can be bent into moving objects such as aircraft, rockets, satellites, space probes, planetary probes, and spacecraft. It is also possible to mount a power storage device that can be used.

[0104] 10A and 10B show examples of vehicles using one embodiment of the present invention. 100 is an electric vehicle that uses an electric motor as a power source for running. A hybrid vehicle that can select between an electric motor and an engine as a power source for driving. When a laminated secondary battery is installed in a vehicle, multiple laminates are used. Install a battery module that integrates rechargeable batteries with a nate structure in one or more locations. By using one embodiment of the present invention, the power storage device itself can be made smaller and lighter. For example, a curved battery device can be installed inside the tire to realize a vehicle with a long driving range. In addition, various types of power storage devices can be placed in gaps in the vehicle, and the trunk The car 8100 has a power storage device. The storage device not only drives the electric motor 8106 but also the headlights 8101 and Power can be supplied to a light emitting device such as a room light (not shown).

[0105] In addition, the power storage device may be used for displaying information such as a speedometer and a tachometer of the automobile 8100. The power storage device can supply power to the navigation system of the automobile 8100. The present invention can provide power to semiconductor devices such as distribution systems.

[0106] The automobile 8200 shown in FIG. 10B is a power storage device of the automobile 8200. It can be charged by receiving power from an external charging facility using a contactless power supply system or other methods. FIG. 10(B) shows the charging of electricity from a ground-mounted charging device 8021 to a storage battery mounted on an automobile 8200. 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 determined as appropriate using the specified methods such as CHAdeMO (registered trademark) and Combo. The charging device 8021 may be a charging station provided in a commercial facility, or For example, plug-in technology allows the system to be connected to an external power supply. The power storage device 8024 mounted on the automobile 8200 can be charged by the This can be done by converting AC power to DC power via a converter such as a CDC converter. do.

[0107] 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 two vehicles. A solar cell may be provided in the storage unit to charge the power storage device when the vehicle is stopped or running. The supply of power through contact can be achieved by electromagnetic induction or magnetic resonance.

[0108] According to one aspect of the present invention, the degree of freedom in the installation location of the power storage device is increased, and vehicle design can be made more efficient. Furthermore, according to one embodiment of the present invention, the characteristics of the power storage device can be improved. Therefore, the power storage device itself can be made smaller and lighter. If possible, this will contribute to reducing the vehicle's weight, thereby improving the vehicle's range. The electric storage device installed in the vehicle can also be used as a power supply source for vehicles other than the vehicle. This allows avoiding the use of commercial power sources during peak power demand periods.

[0109] Note that the content (or even a part of the content) described in one embodiment may be used in conjunction with that embodiment. Other content (or even part of content) described in the above, and / or one or more other implementations The content (or part of the content) described in the form of You can do things like:

[0110] The contents described in the embodiments are explained in detail in each embodiment using various drawings. This refers to the content that is stated or the content that is stated using the text in the specification.

[0111] In addition, a drawing (or a part thereof) described in one embodiment may be different from another part of the drawing, Another figure (or a part thereof) described in the embodiment, and / or one or more By combining with the figure (or a part thereof) described in another embodiment of the present invention, , and many more diagrams can be constructed.

[0112] In addition, regarding the contents not specified in the drawings or text in the specification, Alternatively, the upper limit of a certain value can be set. When a numerical range is listed, such as a lower limit, you can narrow the range arbitrarily. Or, by excluding one point within the scope, one aspect of the invention that excludes part of the scope is defined. As a result, for example, the prior art can be included within the technical scope of one aspect of the present invention. It can be stipulated that it will not be included.

[0113] As a specific example, a circuit diagram using first to fifth transistors in a circuit is shown below. In that case, the circuit does not have a sixth transistor. Alternatively, the circuit may be defined as an invention that does not have a capacitance element. Furthermore, it is possible to specify that the circuit has a specific connection structure. The invention can be configured by specifying that the semiconductor device does not have a sixth transistor. Alternatively, it is specified that the circuit does not have a capacitive element having a specific connection structure. For example, the gate of the first transistor is connected to the gate of the second transistor. It is possible to define the invention as not having a sixth transistor. Alternatively, for example, a capacitor element having a first electrode connected to the gate of the third transistor may be provided. It is possible to define the invention as not having

[0114] As another example, for a certain value, for example, "a certain voltage is 3V or more and 10V or less." In that case, for example, if a certain voltage is -2V, It is possible to specify one aspect of the invention as "excluding cases where the voltage is greater than or equal to 1 V and less than or equal to 1 V." For example, one aspect of the invention may be defined as excluding cases where a certain voltage is 13 V or higher. It is also possible to define the invention as requiring that the voltage be between 5V and 8V. It is possible to define the invention as having a voltage of approximately 9V. For example, the voltage is between 3V and 10V, but excluding the case where it is 9V. It is also possible to define an invention as follows: Even if it is stated that "it is preferable that these conditions are met" or "it is preferable that these conditions are met," , and certain values ​​are not limited to those descriptions. That is, "preferred," "preferred," etc. However, even if it is described as such, it is not necessarily limited to such description.

[0115] As another specific example, regarding a certain value, for example, "a certain voltage is preferably 10V" may be used. In that case, for example, if a certain voltage is between -2V and 1V, It is possible to define one aspect of the invention as "except when One aspect of the invention can be defined as excluding cases where the voltage is 13V or higher.

[0116] Another example is when describing the properties of a substance, for example, "a certain film is an insulating film." In that case, it is assumed that the insulating film is an organic insulating film. Alternatively, for example, the insulating film may be an inorganic insulating film. It is possible to define one aspect of the invention as excluding the case where the membrane is a velum. It is possible to define one aspect of the invention as excluding cases where the film is a conductive film. For example, it is possible to define one aspect of the invention as excluding cases where the film is a semiconductor film. It is Noh.

[0117] As another example, regarding a certain laminated structure, for example, "a certain film is present between film A and film B" In that case, for example, if the film is a stack of four or more layers, Or, for example, it is possible to define the invention as excluding the case of a film A and its It is possible to define the invention as excluding cases where a conductive film is provided between the film and the .

[0118] It should be noted that one aspect of the invention described in this specification etc. may be carried out by various people. However, the implementation may involve multiple people. For example, in the case of a transmission and reception system, Company A manufactures and sells the transmitter, and Company B manufactures the receiver. Another example is a device that has a transistor and a light-emitting element. In the case of a light-emitting device, the semiconductor device in which the transistor is formed is manufactured and sold by Company A. Company B then purchases the semiconductor device and deposits a light-emitting element on it. In some cases, the light-emitting device is completed after the manufacturing process.

[0119] In such a case, the inventor may claim patent infringement against either Company A or Company B. In other words, it is possible to create an embodiment of the invention that is only implemented by Company A. It is possible to construct an invention that is only implemented by Company B as a separate invention. In addition, it is possible to assert patent infringement against Company A or Company B. It can be determined that one aspect of the invention is clear and described in the present specification, etc. For example, in the case of a transmission and reception system, there are descriptions for only the transmitter and only the receiver. Even if the description of such a case is not included in the present specification, the transmitter alone constitutes one aspect of the invention. The receiver alone can constitute an aspect of another invention, and one aspect of those inventions can be is clear and can be judged to be described in the present specification etc. Another example is In the case of a light-emitting device having a transistor and a light-emitting element, the transistor is formed The present invention is not limited to the description of only a semiconductor device having a light emitting element or the description of only a light emitting device having a light emitting element. Even if not specified in the specification, one embodiment of the invention can be realized by a semiconductor device having a transistor formed therein. One embodiment of the present invention can be configured by a light-emitting device having only a light-emitting element. Therefore, it is considered that one aspect of the invention is clear and described in the present specification, etc. can be done.

[0120] In this specification, the terms "active elements" and "passive elements" are used interchangeably. For all terminals of elements such as capacitors and resistors, the connection destination must be specified. However, a person skilled in the art may be able to compose an aspect of the invention. Even if the destination is not specified, one aspect of the invention can be said to be clear. When the content is described in this specification, etc., one aspect of the invention that does not specify the connection destination is In particular, if the terminals are connected to multiple If such a case is considered, there is no need to limit the connection destination of the terminal to a specific location. Therefore, there are active elements (transistors, diodes, etc.) and passive elements (capacitance elements, resistance elements, etc.) By specifying the connection destinations of only some of the terminals possessed by a device, etc., It may be possible to configure one aspect.

[0121] In this specification and the like, if at least the connection destination of a certain circuit is specified, it is understood by those skilled in the art. It may be possible for a person skilled in the art to identify an invention. A person skilled in the art may be able to identify an invention by at least specifying the function. In other words, if the function is specified, it can be said that one aspect of the invention is clear. It may be possible to determine that one aspect of the invention is described in the present specification. Therefore, even if the function of a circuit is not specified, specifying the connection destination can be considered an aspect of an invention. and can constitute one aspect of the invention. Even if the connection destination of a certain circuit is not specified, if the function is specified, it can be considered as one aspect of the invention. It is disclosed and can constitute one aspect of the invention.

[0122] In addition, in this specification and the like, in the figures or text described in a certain embodiment, it is possible to extract a part thereof to constitute one aspect of the invention. Therefore, when a figure or text describing a certain part is described, the content obtained by extracting a part of the figure or text thereof is also disclosed as one aspect of the invention and can constitute one aspect of the invention. And it can be said that one aspect of the invention is clear. Therefore, for example, in drawings or text in which one or more active elements (such as transistors and diodes), wirings, passive elements (such as capacitive elements and resistive elements), conductive layers, insulating layers, semiconductor layers, organic materials, inorganic materials, components, devices, operation methods, manufacturing methods, etc. are described, it is assumed that a part thereof can be extracted to constitute one aspect of the invention. For example, from a circuit diagram composed of N (N is an integer) circuit elements (such as transistors and capacitive elements), M ( M is an integer and M < N) circuit elements (such as transistors and capacitive elements) are extracted to constitute one aspect of the invention. As another example, from a cross-sectional view composed of N (N is an integer) layers, M ( M is an integer and M < N) layers are extracted to constitute one aspect of the invention. [[ID=2�]] ​​​​​​​​​​​​"A has B and E," "A has E and F," "A has C, E, and F," Alternatively, it is possible to construct an aspect of the invention such as "A has B, C, D, and E." is.

[0123] In this specification, etc., in a drawing or text that describes one embodiment, Therefore, when at least one specific example is described, it is not possible to derive a generic concept of that specific example. This will be easily understood by those skilled in the art. When at least one specific example is described in a figure or text, the general outline of that specific example is The invention is also disclosed as an aspect of the invention and may constitute an aspect of the invention. Therefore, one aspect of the invention can be said to be clear.

[0124] In this specification, at least the contents shown in the drawings (or even a part of the drawings) This is disclosed as one aspect of the invention and can constitute one aspect of the invention. Therefore, if something is shown in a diagram, it is not necessarily stated in words. However, the content is disclosed as one aspect of the invention and constitutes one aspect of the invention. Similarly, even if a part of the drawings is taken out, it can be regarded as one embodiment of the invention. This is disclosed as an embodiment of the present invention. It can be said that one aspect of the invention is clear. [Example]

[0125] In this embodiment, a plurality of sets of a positive electrode, a separator, and a negative electrode are prepared, and a laminate that becomes an outer casing is formed. The positive electrode lead connected to the multiple positive electrodes and the negative electrode lead connected to the multiple negative electrodes are enclosed in a protective film and sealed. A secondary battery sample was prepared in which the negative electrode lead protruded, and the sample was bent. After the experiment, an X-ray CT image was taken to check for any damage to the internal electrodes. I checked to see what was going on.

[0126] First, an electrode having the top surface shape shown in FIG. 13(A) was fabricated as a positive electrode. Aluminum was used.

[0127] Laser processing was performed on the above positive electrode to form a slit with a width of 0.5 mm to 5 mm. In this example, slits with a width of 2 mm were formed in two places as shown in FIG. The angle α between the first slit and the second slit was set to less than 90 degrees.

[0128] In addition, an electrode having the top surface shape shown in FIG. 13(B) was fabricated as a negative electrode. Copper was used.

[0129] The negative electrode was subjected to laser processing to form 2 mm wide slits in two locations. The angle β between the first slit and the second slit was set to less than 90 degrees.

[0130] Next, six pairs of laser-processed positive and negative electrodes and separators were prepared (i.e., A total of 12 sheets of positive and negative electrodes were prepared and stacked. The protruding parts of the positive electrode current collector and one lead electrode were then surrounded by a laminate film. The negative electrode current collector protrusions were electrically connected to another lead electrode by wave welding. were connected in the same way.

[0131] Next, the electrolyte is injected into the area surrounded by the laminate film, and the laminate film is The electrodes and the electrolyte were sealed by thermocompression bonding to prepare a secondary battery sample.

[0132] This sample was folded multiple times and examined using X-ray CT to check whether any breaks occurred around the electrode tabs. Figure 14 shows an X-ray CT image of the sample. Since no scratches were observed, the electrode shapes shown in Figures 13(A) and 13(B) are the same as those of the sump. When the cable is bent, the edge of the electrode is pulled, preventing cracks from occurring around the electrode tab. It is very effective. [Example]

[0133] In this example, a power storage device using one embodiment of the present invention is a thin power storage device as described in Example 1. A secondary battery (lithium ion secondary battery) was fabricated and subjected to initial and bending tests using a bending tester. After the test, the charge / discharge characteristics were evaluated.

[0134] The materials and manufacturing method of the secondary battery used as a sample in this example will be described.

[0135] First, for the positive electrode, LiCoO2 is used as the positive electrode active material, and a conductive additive and binder are added to it. Acetylene black (AB) and PVDF were mixed as the dye. The mixing ratio of these was as follows: The positive electrode current collector was 90% by weight of LiCoO2, 5% by weight of AB, and 5% by weight of PVDF. The body is made of 20 μm thick aluminum, and LiCo is applied to both sides or one side of the positive electrode current collector. After coating the mixture of O2, AB and PVDF, the top surface shape shown in Figure 13(A) was obtained. After laser processing, slits with a width of 2 mm were formed in two places. The pole was washed with ethanol.

[0136] Next, for the negative electrode, graphite is used as the negative electrode active material, and carbon black is used as a conductive additive and binder. Vapor grown carbon fiber (VGCF), carboxymethyl cellulose (CMC) and styrene The blend ratio of these was 96% by weight of graphite, 10% by weight of VGC, and 10% by weight of styrene butadiene rubber (SBR). The negative electrode current collector contained about 1% by weight of F, about 1% by weight of CMC, and about 1% by weight of SBR. Copper with a thickness of 18 μm was used. Graphite, VGCF, CMC and After coating the mixture of SBR and PET, the top surface was shaped as shown in Figure 13(B). After laser processing, the negative electrode was Washed with.

[0137] In this example, the positive electrode is an electrode coated on both sides with a positive electrode active material, a conductive additive, and a binder. The negative electrode was made of a sheet of aluminum alloy coated with a negative electrode active material, a conductive additive, and a binder on both sides. Two electrodes were used, and two electrodes coated on one side with negative electrode active material, conductive additive, and binder. In other words, a total of seven metal foils were used for the positive and negative electrodes.

[0138] Next, the electrolyte was an organic solvent mixed with EC:DEC:EMC in a ratio of 3:6:1 (by weight). 1.2 mol / L of LiPF6 was dissolved in the solution, and propane sultone (PS The resin used contained 0.5% by weight of PEG-1000 and 0.5% by weight of vinylene carbonate (VC).

[0139] The separator was made of polypropylene.

[0140] The exterior is made of embossed laminate film. The film is made of a metal film (aluminum film in this case) and a plate made of organic material. A film with a multi-layer structure containing a plastic film (heat-sealable resin film in this case) as one layer. It's Room.

[0141] The above laser processed positive and negative electrodes and separator are stacked and surrounded by a laminate film. Then, the protrusions of the positive electrode current collectors and one lead electrode were electrically connected by ultrasonic welding. Similarly, the protruding portions of the negative electrode current collectors were connected to another lead electrode.

[0142] Then, to leave one side for the electrolyte, the laminate film is heat pressed against two sides. During the thermocompression bonding, the sealing layer provided on the lead terminal also melted and became the lead terminal. The laminate film was fixed in place. Then, the laminate film was placed in a reduced pressure or inert atmosphere. The desired amount of electrolyte was dropped into the inside of the bag-shaped laminate film. The remaining peripheral edge of the film that had not been thermocompressed was then thermocompressed to seal it.

[0143] In this manner, a sample secondary battery having a capacity of about 300 mAh was prepared.

[0144] The secondary battery was bent and fixed to a frame with a curved surface with a radius of curvature of approximately 40 mm. This is Figure 15(A).

[0145] In addition, the X-ray CT image of the secondary battery fixed to the frame corresponds to Figure 15(B). do.

[0146] Also, after charging, disassemble the lithium-ion secondary battery, remove it, and hold the positive electrode with tweezers. A photograph of the positive electrode is shown in Figure 15(C), and a photograph of the negative electrode is shown in Figure 15(D).

[0147] In addition, out of a total of 10,000 bending tests, 0, 1,000, 3,000, and 6,000 times At the 10,000th time point, an X-ray CT image was taken to check for internal damage. 16(A), 16(B), 16(C), 16(D), and 16(E). After each X-ray CT analysis, the battery was charged and discharged to confirm its characteristics. The charge-discharge characteristics are shown in Figure 16(G). The bending test was carried out in the same manner as the bending test during charging described later. It was.

[0148] FIG. 16(F) shows a photograph of the appearance of the secondary battery after the 10,000-cycle bending test.

[0149] In addition, the battery was repeatedly bent several thousand times during charging from the start of charging to full charge. The charging characteristics of the lithium ion secondary battery measured are shown in FIG. Using an experimental device, the electrode part of the secondary battery is sandwiched between thin metal plates from above and below, and the maximum curvature radius is 150 m. The bending test was carried out by repeatedly applying a deformation of 40 mm and a minimum curvature radius of 40 mm. The maximum curvature radius of 150 mm and the minimum curvature radius of 40 mm are repeated 1000 times at 10-second intervals. The charging was performed at a constant current of 61 mA, equivalent to 0.2 C, until the voltage reached 4.1 V. Thereafter, constant voltage charging was carried out at 4.1 V until the current value reached 3 mA.

[0150] In addition, bending tests were repeatedly performed several thousand times during discharge from the start to the end of discharge. The measured discharge characteristics of the lithium ion secondary battery are shown in FIG. The bending test during charging was carried out in the same manner as in the previous test. Discharging was carried out at 61 mA, which corresponds to 0.2 C, for 2.5 seconds. Constant current discharge was performed until the temperature reached V.

[0151] Here, we will explain the charge rate and discharge rate. For example, When charging a secondary battery with a constant current, a charge rate of 1C is the current at which charging is completed in exactly one hour. The current value is I [A], and a charging rate of 0.2C is I / 5 [A] (i.e., Similarly, a discharge rate of 1C is the current value at which charging is completed in just 5 hours. The discharge rate of 0.2C is the current value I [A] at which the discharge is completed in 1 hour. 5 [A] (i.e., the current value at which discharge is completed in exactly 5 hours).

[0152] From the results of Figures 17(A) and 17(B), it can be seen that even when the bending test was performed during charging and discharging, the voltage No adverse effects such as fluctuations were observed. [Explanation of symbols]

[0153] 11 Film 12 Positive electrode current collector 12a Positive electrode current collector 12b Positive electrode current collector 12c positive electrode current collector 12d Positive electrode current collector 13 Separator 14 Negative electrode current collector 15 Sealing layer 16a Lead electrode 16b Lead electrode 17 Thermocompression bonding area 18 Cathode active material layer 19 Negative electrode active material layer 20 Electrolyte 21 Break 27 Aperture 30 Adhesive layer 40 Secondary battery 1700 curved surface 1701 Plane 1702 Curve 1703 Radius of curvature 1704 Center of curvature 1800 Center of curvature 1801 Film 1802 radius of curvature 1803 Film 1804 radius of curvature 7100 Mobile Phone 7101 Housing 7102 Display section 7103 Operation button 7104 Energy storage devices 7105 Lead electrode 7106 Current collector 7400 mobile phone 7401 Housing 7402 Display section 7403 Operation button 7404 External connection port 7405 Speaker 7406 Microphone 7407 Electricity storage devices 7408 Lead electrode 7409 Current collector 7600 Vacuum cleaner 7601 Lead electrode 7602 Lead electrode 7603 Operation button 7604 Energy storage devices 7605 Energy storage devices 7700 Electronic equipment 7701 Hinge 7702 Display section 7703 Hinge 7704 Energy storage devices 8021 Charging device 8022 cable 8024 Electricity storage device 8100 Automobiles 8101 Headlight 8106 Electric motor 8200 Automobiles

Claims

[Claim 1] A secondary battery having first and second current collectors and first and second active material layers, the first active material layer is provided on the first current collector, the second active material layer is provided on the first active material layer, the second current collector is provided on the second active material layer, A secondary battery, wherein one or both of the first current collector and the second current collector has a slit or opening at at least one location.

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