Lithium ion secondary battery

Abstract

To provide an electronic apparatus of a novel structure, specifically, provide an electronic apparatus of a novel structure which can be formed in various appearance shapes.SOLUTION: Specifically, an active material layer is formed on one side or both sides of a current collector and then, the active material layer in a bendable region is partially removed. The region of the active material layer to be removed can be line-shaped, dot-shaped or square-shaped. After the active material layer is formed on one side or both the sides of the current collector, laser processing is performed for removing a part of the active material layer in an irradiated region using laser beams, etc. Since the active material layer is not formed in a region where a surface of the current collector is exposed, this region is a region which does not function as a battery. Formation of such a region can realize a secondary battery including a movable region over a wide range.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD

[0001] One aspect of the present invention relates to an article, a method, or a manufacturing method. Alternatively, the present invention relates to a process, a machine, a manufacture, or a composition of matter. One aspect of the present invention relates to a method for manufacturing a semiconductor device, a display device, a light-emitting device, a power storage device, a lighting device, or an electronic device. In particular, it relates to an electronic device and its operating system. Note that in this specification, the electronic device refers to all devices having a secondary battery, and an electro-optical device having a secondary battery, an information terminal device having a secondary battery, etc. are all electronic devices.

[0002]

BACKGROUND ART

[0003] Electronic devices carried by users and electronic devices worn by users are being actively developed. For example, a thin portable book is described in Patent Document 1.

[0004] Electronic devices carried by users and electronic devices worn by users operate using a secondary battery as a power source. Electronic devices carried by users are desired to be used for a long time, and for this purpose, a large-capacity secondary battery may be used. When a large-capacity secondary battery is built into an electronic device, there is a problem that the large-capacity secondary battery is large and heavy. Therefore, the development of a small or thin and large-capacity secondary battery that can be built into a portable electronic device is underway.

[0005] Patent Document 1 discloses a rectangular lithium-ion secondary battery in which an active material mixture layer is composed of a region having a plurality of openings and a region not having an opening, and at least a bent portion of the collective sheet is covered with a region having a plurality of openings.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] When a metal can is used as the exterior body, there is a problem that the weight of the secondary battery itself increases. Also, in order to realize a thin secondary battery, it is difficult to manufacture a thin metal can by forming process, and it is also difficult to produce a secondary battery using a thin metal can.

[0008] When using a film (also called a laminate film) containing a laminate of a metal foil (such as aluminum, stainless steel, etc.) and a resin (heat-sealable resin) as the exterior body, it is lighter than a secondary battery using a metal can, and a thin secondary battery can be produced. For the user's wearing comfort, a display device worn on the body is required to be lightweight, miniaturized, and furthermore, the entire electronic device including the driving device and power source of the display device is required to be lightweight.

[0009] is required.

[0010] To provide an electronic device with a novel structure. Specifically, an electronic device with a novel structure that can have various external shapes can be provided. To provide an electronic device with a novel structure.

[0011] Alternatively, an aspect of the present invention aims to provide a novel power storage device, a novel secondary battery, etc. Note that the description of these problems does not prevent the existence of other problems. Note that this description One aspect of the invention does not necessarily need to solve all of these problems. In addition, other problems will become apparent from the descriptions in the specification, drawings, claims, etc., and it is possible to extract these other problems from the descriptions in the specification, drawings, claims, etc.

Means for Solving the Problems

[0012] When a film is used for the exterior body of a secondary battery, the strength of the film is weaker than that of a metal can, and when a force is applied from the outside, there is a risk of damaging the current collector disposed inside the exterior body or the active material layer provided on the surface of the current collector.

[0013] When manufacturing a flexible secondary battery or a bent secondary battery, when a plurality of electrodes are bent, they are bent at different curvatures. The electrode farther from the center of curvature is curved more than the electrode closer to the center of curvature, and the position of the end portion is displaced or pulled. At the end of the electrode, there is a portion that is electrically connected to the lead (also called the electrode tab portion). Note that no active material layer is provided on the electrode tab portion.

[0014] A thin secondary battery using a laminate film for the exterior body has an electrode shape that is prone to cracking, that is, a protruding portion (also called an electrode tab portion or a lead terminal portion) where a part protrudes for pulling out the lead electrode.

[0015] When manufacturing a thin secondary battery, a combination of a first electrode (positive electrode), an active material layer, and a second electrode (negative electrode) is laminated in a plurality in the region surrounded by the exterior body. In addition, after overlapping the plurality of first electrodes, ultrasonic bonding or the like is performed to fix the end portions. Similarly, for the second ​​​​​​​​​​​The electrodes of 2 are also ultrasonically joined or the like to fix the ends after overlapping the second electrodes with each other.

[0016] As the number of stacked layers increases, the capacitance increases and the thickness also increases. Therefore, the difference in the radius of curvature becomes large. As the difference in the radius of curvature becomes larger, the position of the end of the electrode farther from the center of curvature is greatly displaced or pulled compared to the electrode closer to the center of curvature. or pulled.

[0017] Specifically, after forming an active material layer on one or both sides of the current collector, the active material layer in the bent region is partially removed. The region where the active material layer is removed can be linear, dot-shaped, mesh-shaped, or the like. and so on.

[0018] One configuration of the invention disclosed in this specification includes a current collector, a plurality of active material layers in contact with the current collector, and an electrolytic solution in contact with the current collector and the plurality of active material layers, and the plurality of active material layers are arranged side by side at intervals in either the long side direction or the short side direction of the current collector. It is a secondary battery.

[0019] After the active material layer is formed on the surface of the current collector with a certain film thickness over the entire surface, the surface of the current collector is exposed by partially removing it by irradiation with a laser beam, cutting, pressing, or the like, and a pattern (such as a stripe pattern, dot pattern, mesh pattern, etc.) is formed. For example, when a stripe pattern is formed the pitch of adjacent active material layers is made uniform. Specifically, after forming an active material layer on one or both sides of the current collector, a laser process is performed to remove a part of the active material layer in the irradiation region using a laser beam or the like. and so on. After the active material layer is formed on one or both sides of the current collector, a laser process is performed to remove a part of the active material layer in the irradiation region using a laser beam or the like. processing.

[0020] In the region where the surface of this current collector is exposed, no active material layer is formed, and adjacent active material layers are By forming such an area, it is possible to achieve a wide range of motion. For example, a secondary battery having a movable range in the upward or downward direction of the end of a collector It is possible to achieve this.

[0021] Alternatively, a part of the current collector used in a secondary battery may be cut to produce a complex pattern (e.g., a meandering By using this shape, the current collector farther from the center of curvature is curved more than the current collector closer to the center of curvature. The position of the end is prevented from shifting from the position of the current collector close to the center of curvature, or The tension applied to the current collector, which is far from the center, may be reduced. In this case, the current collector may be formed in a complex shape to match the shape of the electronic device. For example, in the case of a glasses-type electronic device, the shape of the glasses frame is preferably A secondary battery may be housed in a portion, for example, in the temple.

[0022] By adjusting the intensity of the laser light, it is possible to remove a portion of the current collector. By setting the laser irradiation conditions to be weaker than the laser irradiation for removal, the current collector is left unremoved. It is also possible to remove the active material layer only from the affected area.

[0023] Another embodiment of the present invention is a current collector and a plurality of active material layers in contact with the current collector. and an electrolyte in contact with the current collector and the plurality of active material layers, and the top surface of the current collector has a meandering portion. The meandering portion has at least two narrow portions, and at least one is a secondary battery characterized in that the boundaries of adjacent active material layers overlap.

[0024] In the above configuration, the meandering portion has a meandering, wavy, or multiple curved pattern. It can be said that this part becomes the bendable part of the secondary battery. When the end of the secondary battery is deformed by holding it in the upper surface direction or the lower surface direction of the end of the secondary battery, the end is pulled, and even if the meandering part extends, the current collector can withstand the deformation of the secondary battery without being cut. When the end of the secondary battery is deformed by holding it in the upper surface direction or the lower surface direction of the end of the secondary battery, the end is pulled, and even if the meandering part extends, the current collector can withstand the deformation of the secondary battery without being cut. It can be said that this part becomes the bendable part of the secondary battery. When the end of the secondary battery is deformed by holding it in the upper surface direction or the lower surface direction of the end of the secondary battery, the end is pulled, and even if the meandering part extends, the current collector can withstand the deformation of the secondary battery without being cut.

[0025] When using a positive current collector having a meandering shape (meandering pattern) with a plurality of bending parts, the shape of the negative current collector is different from that of the positive current collector. When providing tab electrodes, since there is a risk of short - circuit if the positive and negative tab electrodes are at a close distance, the positive current collector and the negative current collector are overlapped so that the tab electrodes of the positive and negative electrodes are at positions with a wide interval. Note that a tab electrode for electrical connection is connected to the tip of the meandering pattern of the current collector. When using a positive current collector having a meandering shape (meandering pattern) with a plurality of bending parts, the shape of the negative current collector is different from that of the positive current collector. When providing tab electrodes, since there is a risk of short - circuit if the positive and negative tab electrodes are at a close distance, the positive current collector and the negative current collector are overlapped so that the tab electrodes of the positive and negative electrodes are at positions with a wide interval. Note that a tab electrode for electrical connection is connected to the tip of the meandering pattern of the current collector. When using a positive current collector having a meandering shape (meandering pattern) with a plurality of bending parts, the shape of the negative current collector is different from that of the positive current collector. When providing tab electrodes, since there is a risk of short - circuit if the positive and negative tab electrodes are at a close distance, the positive current collector and the negative current collector are overlapped so that the tab electrodes of the positive and negative electrodes are at positions with a wide interval. Note that a tab electrode for electrical connection is connected to the tip of the meandering pattern of the current collector. When using a positive current collector having a meandering shape (meandering pattern) with a plurality of bending parts, the shape of the negative current collector is different from that of the positive current collector. When providing tab electrodes, since there is a risk of short - circuit if the positive and negative tab electrodes are at a close distance, the positive current collector and the negative current collector are overlapped so that the tab electrodes of the positive and negative electrodes are at positions with a wide interval. Note that a tab electrode for electrical connection is connected to the tip of the meandering pattern of the current collector.

[0026] Moreover, it is not limited to partially removing the active material layer by irradiation or cutting of laser light after forming the entire surface with a certain film thickness on the surface of the current collector. The thickness of the active material layer may be partially reduced by pressing the active material layer. Also, when performing partial pressing, pressure is applied to the current collector, and the current collector can also be partially thinned. By partially thinning the current collector, the secondary battery has the effect of expanding the movable range at the end of the secondary battery. Moreover, it is not limited to partially removing the active material layer by irradiation or cutting of laser light after forming the entire surface with a certain film thickness on the surface of the current collector. The thickness of the active material layer may be partially reduced by pressing the active material layer. Also, when performing partial pressing, pressure is applied to the current collector, and the current collector can also be partially thinned. By partially thinning the current collector, the secondary battery has the effect of expanding the movable range at the end of the secondary battery. Moreover, it is not limited to partially removing the active material layer by irradiation or cutting of laser light after forming the entire surface with a certain film thickness on the surface of the current collector. The thickness of the active material layer may be partially reduced by pressing the active material layer. Also, when performing partial pressing, pressure is applied to the current collector, and the current collector can also be partially thinned. By partially thinning the current collector, the secondary battery has the effect of expanding the movable range at the end of the secondary battery. Moreover, it is not limited to partially removing the active material layer by irradiation or cutting of laser light after forming the entire surface with a certain film thickness on the surface of the current collector. The thickness of the active material layer may be partially reduced by pressing the active material layer. Also, when performing partial pressing, pressure is applied to the current collector, and the current collector can also be partially thinned. By partially thinning the current collector, the secondary battery has the effect of expanding the movable range at the end of the secondary battery. Moreover, it is not limited to partially removing the active material layer by irradiation or cutting of laser light after forming the entire surface with a certain film thickness on the surface of the current collector. The thickness of the active material layer may be partially reduced by pressing the active material layer. Also, when performing partial pressing, pressure is applied to the current collector, and the current collector can also be partially thinned. By partially thinning the current collector, the secondary battery has the effect of expanding the movable range at the end of the secondary battery.

[0027] One of the other configurations of the invention disclosed in this specification is a secondary battery having a current collector, an active material layer in contact with the current collector, and an electrolyte in contact with the active material layer, wherein the active material layer has a thick - film region and a thin - film region, and the thin - film region is linearly arranged on the current collector. One of the other configurations of the invention disclosed in this specification is a secondary battery having a current collector, an active material layer in contact with the current collector, and an electrolyte in contact with the active material layer, wherein the active material layer has a thick - film region and a thin - film region, and the thin - film region is linearly arranged on the current collector. One of the other configurations of the invention disclosed in this specification is a secondary battery having a current collector, an active material layer in contact with the current collector, and an electrolyte in contact with the active material layer, wherein the active material layer has a thick - film region and a thin - film region, and the thin - film region is linearly arranged on the current collector. One of the other configurations of the invention disclosed in this specification is a secondary battery having a current collector, an active material layer in contact with the current collector, and an electrolyte in contact with the active material layer, wherein the active material layer has a thick - film region and a thin - film region, and the thin - film region is linearly arranged on the current collector.

[0028] In each of the above - mentioned configurations, the active material layer contains lithium, and the secondary battery using the above - mentioned configuration is a lithium It is a lithium ion secondary battery.

[0029] Also, in each of the above configurations, a plurality of current collectors are stacked and enclosed by an exterior body using a film (typically a laminate film) to form a thin secondary battery. To make it easier to bend, embossing may be performed on the film (typically a laminate film).

Advantages of the Invention

[0030] A secondary battery with flexibility or a bent secondary battery can be realized.

[0031] Also, when the secondary battery is bent and the electrodes of the secondary battery are also bent, since a part of the electrode or a part of the active material layer is cut, the end of the electrode is not pulled and cracks do not occur in the electrode. As a result, the reliability of the secondary battery that can be bent or the bent secondary battery can be improved. Also, if the housing of the electronic device is made a flexible housing, part or all of the electronic device including the battery can be bent.

Brief Description of the Drawings

[0032]

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[0033] Hereinafter, an embodiment of the present invention will be described in detail with reference to the 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. The present invention is not limited to the description of the following embodiments. It is not something that can be done.

[0034] "Electrically connected" means connected via "something that has some kind of electrical effect." Here, "something that has some electrical effect" means an electrical signal between connected objects. There are no particular restrictions as long as it allows the exchange of numbers.

[0035] The position, size, range, etc. of each component shown in the drawings are not necessarily the actual size for ease of understanding. Therefore, the disclosed invention may not necessarily represent the position, size, range, etc. Furthermore, the present invention is not limited to the position, size, range, etc. disclosed in the drawings, etc.

[0036] Ordinal numbers such as "first," "second," and "third" are used to avoid confusion of components. It is.

[0037] (Embodiment 1) In this embodiment, with reference to FIGS. 1, 2, 3, 4, and 5, an electrode for a secondary battery and a method for manufacturing the secondary battery according to one aspect of the present invention will be described.

[0038] FIG. 1(A) is a perspective view of a plurality of positive electrode active material layers formed on a positive electrode current collector 12, and the cross-sectional view thereof is FIG. 1(B). The positive electrode current collector 12 has a plurality of positive electrode active material layers formed in contact with one surface. Also, it can be said that the positive electrode current collector 12 has a plurality of positive electrode active material layers formed in a plurality of regions divided on one surface. As a manufacturing method, after applying and drying a slurry, the positive electrode active material layer is partially removed by laser light irradiation to form a plurality of positive electrode active material layers 18a, 18b, 18c, and 18d.

[0039] As the laser light source, ML-7320DL (manufactured by Miyachi Technos Co., Ltd.) with an oscillation wavelength of about 1065 nm is used. After moving the stage, the laser light is scanned by moving the galvanometer mirror.

[0040]

[0041] Also, a cross-sectional view of forming a plurality of positive electrode active material layers 18a, 18b, 18c, and 18d on one side and a plurality of positive electrode active material layers 18e, 18f, 18g, and 18h on the other side is shown in FIG. 1(C). Also, in FIG. 1(C), an example of arranging the ends of the positive electrode active material layers on both sides to coincide is shown, but it is not particularly limited.

[0042] Also, FIG. 1(D) shows an example of forming a plurality of positive electrode active material layers 18a, 18b, 18c, and 18d on one side and a plurality of positive electrode active material layers 18e, 18f, 18g, 18h, and 18i with their positions shifted on the other side.

[0043] ​​​​​​​​​​​​ In addition, in FIG. 1, an example is shown in which the intervals between a plurality of positive electrode active material layers are set to substantially constant pitches, but it is not particularly limited thereto. In FIG. 2(B), an example is shown in which the interval P1 between the positive electrode active material layer 18a and the positive electrode active material layer 18b is made wider than the interval P2 between the positive electrode active material layer 18b and the positive electrode active material layer 18c. Note that FIG. 2(A) is a perspective view and corresponds to FIG. 2(B).

[0044] FIG. 2(C) is a cross-sectional view in which a plurality of positive electrode active material layers 18a, 18b, 18c, and 18d are formed on one side, and a plurality of positive electrode active material layers 18e, 18f, 18g, and 18h are formed on the other side.

[0045] In addition, FIG. 2(D) shows an example in which a plurality of positive electrode active material layers 18a, 18b, 18c, and 18d are formed on one side, and a plurality of positive electrode active material layers 18e, 18f, 18g, 18 h, and 18i are formed on the other side with their positions shifted respectively.

[0046] In addition, a perspective view showing the formation of a positive electrode active material layer 18 with partially different film thicknesses using a roll 80 having a convex portion is shown in FIG. 3(A), and a cross-sectional view is shown in FIG. 3(B). Also, an example of forming positive electrode active material layers 18 with different film thicknesses on both sides is shown in FIG. 3(C). Also, FIG. 3(D) shows an example in which a positive electrode active material layer 18 is formed on one side, and positive electrode active material layers 18 are formed on the other side with the positions of the concave portions shifted respectively. In addition, a perspective view showing the formation of a positive electrode active material layer 18 with partially different film thicknesses using a roll 90 having a convex portion with a wider pitch than the roll 80 having a convex portion is shown in FIG. 4(A), and a cross-sectional view is shown in FIG. 4 In addition, an example of forming positive electrode active material layers 18 with different film thicknesses on both sides is shown in FIG. 4(C). Also, FIG. 4(D) shows an example in which a positive electrode active material layer 18 is formed on one side, and positive electrode active material layers 18 are formed on the other side with the positions of the concave portions shifted respectively. In addition, a perspective view showing the formation of a positive electrode active material layer 18 with partially different film thicknesses using a roll 90 having a convex portion with a wider pitch than the roll 80 having a convex portion is shown in FIG. 4(A), and a cross-sectional view is shown in FIG. 4 (B). Also, an example of forming positive electrode active material layers 18 with different film thicknesses on both sides is shown in FIG. 4(C). Also, FIG. 4(D) shows an example in which a positive electrode active material layer 18 is formed on one side, and positive electrode active material layers 18 are formed on the other side with the positions of the concave portions shifted respectively.

[0047] In addition, a perspective view showing the formation of a positive electrode active material layer 18 with partially different film thicknesses using a roll 90 having a convex portion with a wider pitch than the roll 80 having a convex portion is shown in FIG. 4(A), and a cross-sectional view is shown in FIG. 4 (B). Also, an example of forming positive electrode active material layers 18 with different film thicknesses on both sides is shown in FIG. 4(C). Also, FIG. 4(D) shows an example in which a positive electrode active material layer 18 is formed on one side, and positive electrode active material layers 18 are formed on the other side with the positions of the concave portions shifted respectively. (B). Also, an example of forming positive electrode active material layers 18 with different film thicknesses on both sides is shown in FIG. 4(C). Also, FIG. 4(D) shows an example in which a positive electrode active material layer 18 is formed on one side, and positive electrode active material layers 18 are formed on the other side with the positions of the concave portions shifted respectively. Also, FIG. 4(D) shows an example in which a positive electrode active material layer 18 is formed on one side, and positive electrode active material layers 18 are formed on the other side with the positions of the concave portions shifted respectively. Examples of forming the positive electrode active material layer 18 with a shift are shown.

[0048] Also, Fig. 4(E) shows an example in which after forming the positive electrode active material layer 18 with different film thicknesses in part using the roll 90 having protrusions, laser light is irradiated to form a plurality of positive electrode active material layers 18a, 18b, 18c, 18d.

[0049] Figs. 1, 2, 3, and 4 show a total of 13 types of variations, but are not particularly limited. Also, in this embodiment, examples of the positive electrode active material layer are shown, but laser irradiation may be performed on the negative electrode active material layer, or pressing may be performed with a roll.

[0050] An example of manufacturing the secondary battery 40 using the positive electrode current collector 12 having the positive electrode active material layer shown in Figs. 1, 2, 3, and 4 will be described below.

[0051] Fig. 5(B) is a perspective view of laminating a positive electrode, a separator, and a negative electrode. The positive electrode has at least a current collector and a positive electrode active material layer. Also, the negative electrode has at least a current collector and a negative electrode active material layer. In Fig. 5(B), the electrode for the storage battery (positive electrode or negative electrode) is shown in a rectangular sheet shape, but the shape of the electrode for the storage battery is not limited to this, and any shape can be appropriately selected. In Fig. 5(B ), the active material layer is formed only on one surface of the current collector, but the active material layer may be formed on both surfaces of the current collector. Also, the active material layer does not need to be formed over the entire surface of the current collector, and non-coated regions such as regions for electrically connecting to the electrode lead are appropriately provided.

[0052] The current collector used for the positive electrode or the negative electrode has no particular limitation as long as it exhibits high conductivity without causing a significant chemical change in the secondary battery. For example, gold, platinum, iron, nickel, copper, aluminum , metals such as titanium, tantalum, manganese, and their alloys (such as stainless steel) can be used It is also possible to coat with carbon, nickel, titanium, etc. Further, adding silicon, neodymium, scandium, molybdenum, etc. may improve heat resistance. Also, the current collector can be appropriately used in various forms such as foil, sheet, plate, net, cylindrical, coil, punching metal, expanded metal, porous, and non-woven fabric. Furthermore, in order to increase the adhesion with the active material, the current collector may have fine irregularities on its surface. Also, it is preferable to use a current collector having a thickness of 5 μm or more and 30 μm or less.

[0053] The active material used for the positive electrode or the negative electrode may be a material capable of a reversible reaction with carrier ions such as lithium ions. By pulverizing, granulating, and classifying by appropriate means, the average particle size and particle size distribution of the active material can be controlled.

[0054] Examples of the positive electrode active material used for the positive electrode active material layer 18 include composite oxides having an olivine-type crystal structure, a layered rock salt-type crystal structure, or a spinel-type crystal structure. As the positive electrode active material, for example, compounds such as LiFeO2, LiCoO2, LiNiO2, LiMn2O4, V2O5, Cr2 O5, MnO2 are used.

[0055] Alternatively, a composite material (general formula LiMPO4 (M is one or more of Fe(II), Mn(II), Co(II), Ni(II))) can be used. Representative examples of the general formula LiMPO4 include LiFePO4, LiNiPO4, LiCoPO4, LiMnPO4, LiFe Ni a Ni b PO4, LiFe a Co bPO4, LiFe a Mn b PO4, LiNi a Co b PO4, LiNi a Mn b PO4 (a + b is less than or equal to 1, 0 < a < 1, 0 < b < 1), 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 less than or equal to 1, 0 < c < 1, 0 < d < 1, 0 < e < 1), LiFe f Ni g C o h Mn i PO4 (f + g + h + i is less than or equal to 1, 0 < f < 1, 0 < g < 1, 0 < h < 1, 0 <i < 1) and other 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) can be used. General Formula Li (2-j) MSiO4 representative examples 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 (k + l is 1 or less, 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 (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 (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 in this way and it is possible to do so.

[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) represented by the general formula can be used. Examples of the NASICON-type compound include Fe2(MnO4) 3, Fe2(SO4)3, Li3Fe2(PO4)3, etc. Also, as the positive electrode active material , compounds represented by the general formula Li2MPO4F, Li2MP2O7, Li5MO4 (M = Fe, Mn), perovskite-type fluorides such as NaFeF3, FeF3, metal chalcogenides (sulfides, selenides, tellurides) such as TiS2, Mo S2, etc., and inverse compounds such as LiMVO4 etc. S2, etc., and inverse compounds such as LiMVO4 Oxides having a spinel crystal structure, vanadium oxides (V2O5, V6O 13 , L iV3O8, etc.), manganese oxides, organic sulfur compounds, and other materials can be used.

[0058] In addition, when the carrier ion is an alkali metal ion other than lithium ion or an alkaline earth metal ion, 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.) may be used.

[0059] As the separator 13, cellulose (paper), or an insulator such as polypropylene or polyethylene provided with pores can be used.

[0060] The electrolyte uses a material in which carrier ions can move as an electrolyte and which has lithium ions as carrier ions. Representative examples of the electrolyte include lithium salts such as LiPF6, LiCl O4, LiAsF6, LiBF4, LiCF3SO3, Li(CF3SO2)2N, Li (C2F5SO2)2N, etc. These electrolytes may be used alone or in any combination and ratio of two or more.

[0061] In addition, as the solvent of the electrolyte, a material in which carrier ions can move is used. As the solvent of the electrolyte, an aprotic organic solvent is preferable. Representative examples of the aprotic organic solvent include ethylene carbonate (EC), propylene carbonate, dimethyl carbonate, diethyl carbonate (DEC), ethyl methyl carbonate (EMC), γ-butyrolactone ​​​include acetonitrile, dimethoxyethane, tetrahydrofuran, etc., and one or more of these can be used. Further, a polymer material that is gelled can be used as the solvent of the electrolytic solution, or a polymer material for gelation can be added to the electrolytic solution, etc., to enhance the safety against liquid leakage, etc. Also, the battery can be made thinner and lighter. Representative examples of the gelled polymer material include silicone gel, acrylic gel, acrylonitrile gel, polyethylene oxide-based gel, polypropylene oxide-based gel, gel of fluorine-based polymer, etc. Also, as the solvent of the electrolytic solution, using one or more ionic liquids (room temperature molten salts) that are flame-retardant and hardly volatile can prevent the battery from bursting or catching fire even if the internal temperature rises due to internal short circuit, overcharging, etc. Note that an ionic liquid is a salt in a fluid state and has a high ionic mobility (conductivity). Also, an ionic liquid contains a cation and an anion. Examples of ionic liquids include ionic liquids containing an ethylmethylimidazolium (EMI) cation, or ionic liquids containing an N-methyl-N-propylpiperidinium (PP ) cation, etc. 13

[0062]

[0062]

[0063] Materials capable of reversible reactions with on can be used, and lithium metal, carbon-based materials, alloy-based materials, etc. can be used.

[0064] Lithium metal has a low redox potential (-3.045 V vs. standard hydrogen electrode), and a large specific capacity per weight and volume (3860 mAh / g and 2062 mAh / cm 3 3 ), respectively), so it is preferable.

[0065] Examples of carbon-based materials include graphite, graphitizable carbon (soft carbon), non-graphitizable carbon (hard carbon), carbon nanotubes, graphene, carbon black, etc.

[0066] Examples of graphite include artificial graphite such as mesocarbon microbeads (MCMB), coke-based artificial graphite, and pitch-based artificial graphite, and natural graphite such as spheroidized natural graphite.

[0067] Graphite shows a potential as low as that of lithium metal (0.1 - 0.3 V vs. Li / Li + + ) when lithium ions are inserted into graphite (when forming a lithium-graphite intercalation compound). As a result, lithium-ion secondary batteries can exhibit a high operating voltage. Furthermore, graphite has advantages such as a relatively high capacity per unit volume, small volume expansion, low cost, and high safety compared to lithium metal, so it is preferable.

[0068] As the negative electrode active material, alloy-based materials or oxides capable of performing charge and discharge reactions through alloying and dealloying reactions with lithium can also be used. When the carrier ion is a lithium ion, examples of alloy-based materials include Al, Si, Ge, Sn, Pb, Sb, Bi, ​​​​​​​There is a material containing at least one of Ag, Au, Zn, Cd, In, Ga, etc. Such elements have a large capacity relative to carbon. In particular, silicon has a theoretical capacity of 4200 mAh / g, which is extremely high. Therefore, it is preferable to use silicon as the anode active material. As alloy-based materials using such elements, for example, there are Mg2Si, Mg2Ge, Mg2Sn, SnS 2, V2Sn3, FeSn2, CoSn2, Ni3Sn2, Cu6Sn5, Ag3Sn, Ag3Sb, Ni2MnSb, CeSb3, LaSn3, La3Co2Sn7, CoSb 3, InSb, SbSn, etc.

[0069] In addition, as the anode active material, oxides such as SiO, SnO, SnO2, titanium dioxide (TiO2), lithium titanate (Li4Ti5O 12 ), lithium-graphite intercalation compound (Li x C6), niobium pentoxide (Nb2O5), tungsten oxide (WO2), molybdenum oxide (MoO2 ) can be used. Note that SiO refers to a powder of silicon oxide containing a silicon-rich part, and can also be expressed as SiO (2>y>0). For example, SiO is y , a material containing one or more selected from Si2O3, Si3O4, or Si2O, or a mixture of Si powder and silicon dioxide SiO2 is also included. In addition, SiO may contain other elements (such as carbon, nitrogen, iron, aluminum, copper, titanium, calcium, manganese, etc.). That is, it refers to a material containing one or more selected from single crystal Si, amorphous Si, polycrystalline Si, Si2O3, Si3O4, Si2O, SiO2, and SiO is a colored material. If there is no SiO (X is 2 or more), it is colorless and transparent or white, and can be distinguished. There is no SiO x (X is 2 or more), it is colorless and transparent or white, and can be distinguished. However, after manufacturing a secondary battery using SiO as a material for the secondary battery, when charging and discharging are repeated, if SiO is oxidized, it may be transformed into SiO2.

[0070] In addition, as the negative electrode active material, Li having a Li3N-type structure, which is a complex nitride of lithium and a transition metal, Li (3-x) M x N (M = Co, Ni, Cu) can be used. For example, Li2 .6 Co 0.4 N3 exhibits a large charge-discharge capacity (900 mAh / g, 1890 mAh / cm 3 ) and is preferable.

[0071] When using a complex nitride of lithium and a transition metal, since the negative electrode active material contains lithium ions, it can be preferably combined with materials such as V2O5 and Cr3O8 that do not contain lithium ions as the positive electrode active material. Even when using a material containing lithium ions for the positive electrode active material, by previously desorbing the lithium ions contained in the positive electrode active material, a complex nitride of lithium and a transition metal can be used as the negative electrode active material.

[0072] In addition, a material that undergoes a conversion reaction can also be used as the negative electrode active material. For example, transition metal oxides such as cobalt oxide (CoO), nickel oxide (NiO), and iron oxide (FeO), which do not undergo an alloying reaction with lithium, may be used as the negative electrode active material. As materials that undergo a conversion reaction, further, oxides such as Fe2O3, CuO, Cu2O, RuO2, and Cr2O 3, sulfides such as CoS 3, nitrides such as Zn3N2, Cu3N, and G 0.89 e3N4, phosphides such as NiP2, FeP2, and CoP3, and FeF3, BiF3 ​​​​​This also occurs with fluorides such as. Since the potential of the above fluoride is high, it can be used as a positive electrode active material. It may be used.

[0073] In addition, the negative electrode active material layer 19 may contain, in addition to the above-described negative electrode active material, a binder for enhancing the adhesion of the active material, a conductive auxiliary agent for enhancing the conductivity of the negative electrode active material layer 19, etc. It may have. It may be used.

[0074] In this embodiment, the configuration of the power storage body is, for example, the thickness of the separator 13 is about 15 μm or more and 30 μm or less, the current collector of the positive electrode 101 is about 10 μm or more and about 40 μm or less, the positive electrode active material layer is about 50 μm or more and about 100 μm or less, the negative electrode active material layer is about 50 μm or more and about 100 μm or less, and the current collector of the negative electrode 102 is about 5 μm or more and about 40 μm or less. It is set to.

[0075] As the exterior body, a sheet made of a flexible base material is prepared. The sheet uses a laminate and has an adhesive layer (also called a heat seal layer) on one or both surfaces of the metal film. It is used. The adhesive layer uses a heat-sealable resin film containing polypropylene, polyethylene, etc. In this embodiment, as the sheet, a metal sheet having a nylon resin on the surface of an aluminum foil and provided with a laminate of an acid-resistant polypropylene film and a polypropylene film on the back surface of the aluminum foil is used. This sheet is cut to prepare the film 11. The film 11 is bent at the center, the two ends are overlapped, and three sides are sealed with an adhesive layer. It has a structure. The film 11 is then folded in two at the central portion to obtain the state shown in FIG. 5(A).

[0076] Next, the film 11 is folded in two at the central portion to obtain the state shown in FIG. 5(A).

[0077] Also, as shown in FIG. 5(B), the positive electrode current collector 12, the separator 13, and the negative Prepare a stack of the current collectors 14.

[0078] Then, prepare lead electrodes 16a and 16b having a sealing layer 15 shown in FIG. 5(C). The lead electrodes 16a and 16b are also called lead terminals and are provided to draw out the positive or negative electrode of the secondary battery to the outside of the outer packaging film. The lead electrode 16a is electrically connected to the positive electrode. As the material of the lead electrode 16a, a material that can be used for a positive current collector such as aluminum can be used. Also, the lead electrode 16b is electrically connected to the negative electrode. As the material of the lead electrode 16b, a material that can be used for a negative current collector such as copper can be used.

[0079] Then, the lead electrode 16a and the protruding portion of the positive current collector 12 are electrically connected by ultrasonic welding or the like. And the lead electrode 16b and the protruding portion of the negative current collector 14 are electrically connected by ultrasonic welding or the like.

[0080] Then, in order to leave one side for injecting the electrolytic solution, heat sealing is performed on two sides of the film 11 to seal it (hereinafter, the shape of the film in this state is also referred to as a bag shape). During heat sealing, the sealing layer 15 provided on the lead electrode also melts to fix the space between the lead electrode and the film 11. And, in a reduced pressure atmosphere or an inert atmosphere, a desired amount of electrolytic solution is dropped inside the film 11 that has become a bag shape. And finally, heat sealing is performed on the peripheral edge of the film that was left without performing heat sealing.

[0081] In this way, the secondary battery shown in FIG. 5(D) can be manufactured. Also, the dotted line and the end face region in FIG. 5(D) are heat sealing regions 17. Also, FIG. 5(E) is a view obtained by cutting along the chain line AB in FIG. 5(D).​​​​​​​ is a cross-sectional view. As shown in FIG. 5(E), a plurality of positive electrode active material layers 18 are provided on the positive electrode current collector 12 and a plurality of negative electrode active material layers 19 are provided on the negative electrode current collector 14, and an electrolytic solution 20 is provided between the plurality of positive electrode active material layers 18 and between the plurality of negative electrode active material layers 19. Further, as shown in FIG. 5( E), the secondary battery 40 is sealed with an adhesive layer 30 at its end, and the electrolytic solution 20 is present in the other space. The adhesive layer 30 is formed by melting a part of the film 11 during thermocompression bonding and then cooling it to a solid state.

[0082] In the obtained secondary battery 40, the active material layer is partially removed, and the stress applied when the secondary battery is bent can be relieved. By providing a plurality of active material layers, the secondary battery 40 is more likely to bend and the movable range at the end of the secondary battery is widened.

[0083] Here, the flow of current during charging of the secondary battery will be described with reference to FIG. 5(F). When a secondary battery using lithium is regarded as a single closed circuit, the movement of lithium ions and the flow of current are in the same direction . In a secondary battery using lithium, the anode (positive electrode) and the cathode (negative electrode) are reversed during charging and discharging, and the oxidation reaction and the reduction reaction are reversed. Therefore, 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. Thus, in this specification , whether during charging, discharging, flowing a reverse pulse current, or flowing a charging current, the positive electrode is called the "positive electrode" or the "+ electrode (plus electrode)", and the negative electrode is called the "negative electrode" or the "- electrode (minus electrode)". When using terms such as anode (positive electrode) and cathode (negative electrode) related to oxidation reactions and reduction reactions, during charging and discharging , , ​​It may be reversed and cause confusion. Therefore, the terms anode and cathode shall not be used in this specification. If the terms anode or cathode are used, it shall be specified whether it is during charging or discharging, and it shall also be noted which one corresponds to the positive electrode (plus electrode) and the negative electrode (minus electrode).

[0084] A charger is connected to the two terminals shown in Fig. 5(F), and the secondary battery 40 is charged. As the charging of the secondary battery 40 progresses, the potential difference between the electrodes increases. In Fig. 5(F), the current flows from the external terminal of the secondary battery 40 towards the positive electrode current collector 12, and within the secondary battery 40, it flows from the positive electrode current collector 1 2 towards the negative electrode current collector 14, and from the negative electrode current collector 14 towards the external terminal of the secondary battery 40. The direction of the current flowing is defined as the positive direction. That is, the direction of the charging current flow is defined as the direction of the current.

[0085] In this embodiment, an example of a small battery used in a portable information terminal or the like is shown, but it is not particularly limited and can also be applied to large batteries mounted on vehicles or the like.

[0086] (Embodiment 2) In this embodiment, an example of manufacturing a secondary battery using a current collector having a meandering portion is shown below.

[0087] First, a positive electrode active material layer is formed on one or both sides of a strip-shaped metal foil.

[0088] Next, the positive electrode active material layer is selectively removed by laser light irradiation. The locations to be removed are two locations: a narrow region that will be connected to the electrode lead in a later process and a narrow portion of the meandering portion. Then, laser processing is performed. In this laser processing, both the positive electrode active material layer and the metal foil are processed. ​Selectively remove it. Here, it is processed to draw the contour of the current collector having a meandering portion, and the current collector is formed into a shape. At this stage, the state shown in Fig. 6(A) can be obtained. Fig. 6(A) As shown, a part of the current collector (the root part of the meandering pattern) is exposed, and the positive electrode active material layer 18a and the positive electrode active material layer 18b are formed.

[0089] Also, here, the outer shape of the current collector is formed by laser processing. However, after processing the metal foil into a desired shape using a cutting device or a punching device, it may also be a process of further performing laser processing to form a current collector with a complex shape.

[0090] Also, it is preferable to perform laser processing after forming the active material layer on one or both sides of the positive electrode current collector 12. The cut surface formed by irradiating laser light is desirable because strong energy is applied and the current collector and the active material layer are firmly fixed.

[0091] As shown in Fig. 6(A), there are at least two or more portions with a narrow width in the meandering portion of the current collector, and at least one portion (the root part of the meandering pattern) overlaps with the boundary of the adjacent active material layers (the region between the positive electrode active material layer 18a and the positive electrode active material layer 18b).

[0092] The photograph taken while holding the positive electrode current collector 12 with tweezers is Fig. 6(B). As shown in Fig. 6( A), the width is non-uniform in the meandering portion of the positive electrode current collector 12.

[0093] Next, a negative electrode active material layer is formed on one or both sides of the strip-shaped metal foil.

[0094] Then, the negative electrode active material layer is selectively removed by laser light irradiation. The portion to be removed is later ​​is a narrow region that is connected to the electrode lead by the process. Then, laser processing is performed. This In this laser processing, the contour of the current collector having a meandering portion is processed so as to draw the shape of the current collector is formed.

[0095] A schematic top view of the negative electrode current collector 14 and the negative electrode active material layer 19 is shown in FIG. 6(C), and a photograph taken in a state where the negative electrode current collector is held by a pin set is shown in FIG. 6(D). is.

[0096] As shown in FIG. 6, both the positive electrode and the negative electrode current collectors have meandering portions, but the widths are partially different. The meandering portion can also be called a bent portion of a fold. Also, the meandering portion includes a linear pattern and has a bent pattern shape. In this specification, a part of the contour of the upper surface shape of the current collector that repeats a bend of 90° or more two or more times is called a meandering shape. Also, a part of the contour of the upper surface shape of the current collector that is in a rectangular wave shape, a triangular wave shape, an S-shaped, etc. is also included in the meandering shape. Note that the bends in the meandering shape do not have to repeat the same pattern and may have an irregular bend shape. Also, the portion cut out to form the meandering portion is called a slit . is. is.

[0097] When the positive electrode current collector and the negative electrode current collector are superimposed in a subsequent process, the positive electrode active material layer may be located in a region that overlaps with the slit of the negative electrode current collector. For example, in the case of the current collector of FIG. 6, since the slit of the negative electrode current collector overlaps with a narrow portion of the width of the meandering portion of the positive electrode current collector, if the positive electrode active material layer exists in this portion, there will be no negative electrode active material layer in the region that overlaps with the positive electrode active material layer. In this case the absence of the negative electrode active material layer in the region that overlaps with the positive electrode active material layer may cause problems during the battery reaction . Specifically, the carrier ions emitted from the positive electrode active material layer are closest to the slit is. In this case, since there is no negative electrode active material layer in the region that overlaps with the positive electrode active material layer, there may be problems during the battery reaction . Specifically, carrier ions emitted from the positive electrode active material layer are closest to the slit It will concentrate on the negative electrode active material layer in the adjacent region, and there is a risk that carrier ions will precipitate on the surface of the negative electrode active material layer. Therefore, by removing the positive electrode active material layer without a negative electrode active material layer in the overlapping region, in the case of Fig. 6, the positive electrode active material layer at the narrow part of the width of the meandering part of the positive electrode current collector, by irradiating with laser light, the precipitation of carrier ions can be suppressed.

[0098] Also, for the above reasons, it is preferable that the widths of the slits of the positive electrode and the negative electrode are equal or that the width of the slit of the positive electrode is larger. By increasing the width of the slit of the positive electrode, the positive electrode active material layer without a negative electrode active material layer in the overlapping region can be eliminated or reduced. Therefore, the precipitation of carrier ions on the surface of the negative electrode active material can be suppressed.

[0099] Next, as shown in Fig. 7(A), the positive electrode current collector 12 is sandwiched between the separators 13. Then, a part 13a of the separator 13 that does not overlap with the positive electrode current collector 12 is adhered, and it is manufactured so as to wrap the positive electrode current collector 12 with the separator 13 (Fig. 7(B)). When polypropylene or polyvinylidene fluoride (PVDF) is used for the separator 13, it can be adhered by heat melting at 190 °C to 230 °C.

[0100] Next, as shown in Fig. 7(C), the positive electrode current collector 12 wrapped with the separator 13 and the negative electrode current collector 14 are stacked. At this time, it is preferable to stack a plurality of positive electrode current collectors 12 and negative electrode current collectors 14. In that case, the positive electrode current collector 12 wrapped with the separator 13 and the negative electrode current collector 14 are alternately stacked, and the electrode tab portions of the positive electrode current collectors 12 overlap each other, and the electrode tab portions of the negative electrode current collectors 14 overlap each other. By stacking and electrically connecting them, the capacity of the secondary battery can be increased.

[0101] Then, the stacked separators 13, the positive electrode current collector 12, and the negative electrode current collector 14 are bundled and fixed. The fixing can be performed with an adhesive tape, a resin tape such as a polyimide film coated with an adhesive, etc.

[0102] Next, one lead electrode 16a is electrically connected to the electrode tab portion of the positive electrode current collector 12. Also, the other lead electrode 16b is electrically connected to the electrode tab portion of the negative electrode current collector 14. The electrical connection can be performed by ultrasonic welding. Also, when a plurality of positive electrode current collectors 12 and negative electrode current collectors 14 are stacked, the process of ultrasonic welding the lead electrode 16a and the electrode tab portions of the plurality of positive electrode current collectors 12 to each other, and the process of ultrasonic welding the lead electrode 16b and the electrode tab portions of the plurality of negative electrode current collectors 14 to each other can be processed simultaneously. As a result, conduction between the plurality of positive electrode current collectors 12 and between the plurality of negative electrode current collectors 14 is obtained.

[0103] The lead electrode connected to the positive electrode current collector 12 may be made of a material that can be used for a positive electrode current collector such as aluminum. Also, the lead electrode connected to the negative electrode current collector 14 may be made of a material that can be used for a negative electrode current collector such as copper. Since the lead electrode electrically connected to the positive electrode current collector 12 has the same potential as the positive electrode current collector 12, and the same applies to the negative electrode, the material that can be used for the current collector can be used for the lead electrode.

[0104] Next, as shown in FIG. 8(A), the film 11 is bent at the center. Then, as shown in FIG. 8(B), the periphery of the film 11 is sealed by thermocompression bonding, leaving two sides.​​​​​​​​ As shown in , in this embodiment, since one side is the side where the film 11 is bent, the sealing in this process may be performed on one side 11b. As a result, the stacked separators 13, the positive current collector 12, and the negative current collector 14 can be accommodated in the region surrounded by the film 11. Incidentally, the film 11 may be embossed in advance. By performing the embossing process, a secondary battery that is more easily bent can be obtained. Next, as shown in FIG. 8(C), the positive current collector 12, the separator 13, and the negative current collector 14 are accommodated in the region surrounded by the film 11, and one side 11c of the film 11 is sealed by thermocompression bonding. At this time, the lead electrode 16a and the lead electrode 16b are drawn out to the outside of the region surrounded by the film 11.

[0105] Next, as shown in FIG. 8(D), the electrolyte 20 is injected into the region surrounded by the film 11. Then, while performing evacuation, heating, and pressurization, the remaining one side 11d of the film 11 is sealed as shown in FIG. 8(E). These operations are performed in an environment where oxygen is excluded, such as using a glove box. The evacuation can be performed using a degassing sealer, a liquid injection sealer, or the like. Also, by sandwiching the film 11 with two heatable bars provided in the sealer, heating and pressurization can be performed to seal. Each condition can be, for example, a vacuum degree of 60 kPa, heating at 190°C, and pressurization at 0.1 MPa for 3 seconds. Next, it is preferable to perform an aging process on the secondary battery obtained in the above process.

[0106] Next, as shown in FIG. 8(C), the positive current collector 12, the separator 13, and the negative current collector 14 are accommodated in the region surrounded by the film 11, and one side 11c of the film 11 is sealed by thermocompression bonding. At this time, the lead electrode 16a and the lead electrode 16b are drawn out to the outside of the region surrounded by the film 11. Next, as shown in FIG. 8(C), the positive current collector 12, the separator 13, and the negative current collector 14 are accommodated in the region surrounded by the film 11, and one side 11c of the film 11 is sealed by thermocompression bonding. At this time, the lead electrode 16a and the lead electrode 16b are drawn out to the outside of the region surrounded by the film 11. Next, as shown in FIG. 8(C), the positive current collector 12, the separator 13, and the negative current collector 14 are accommodated in the region surrounded by the film 11, and one side 11c of the film 11 is sealed by thermocompression bonding. At this time, the lead electrode 16a and the lead electrode 16b are drawn out to the outside of the region surrounded by the film 11. Next, as shown in FIG. 8(C), the positive current collector 12, the separator 13, and the negative current collector 14 are accommodated in the region surrounded by the film 11, and one side 11c of the film 11 is sealed by thermocompression bonding. At this time, the lead electrode 16a and the lead electrode 16b are drawn out to the outside of the region surrounded by the film 11.

[0107] Next, as shown in FIG. 8(D), the electrolyte 20 is injected into the region surrounded by the film 11. Then, while performing evacuation, heating, and pressurization, the remaining one side 11d of the film 11 is sealed as shown in FIG. 8(E). These operations are performed in an environment where oxygen is excluded, such as using a glove box. The evacuation can be performed using a degassing sealer, a liquid injection sealer, or the like. Also, by sandwiching the film 11 with two heatable bars provided in the sealer, heating and pressurization can be performed to seal. Each condition can be, for example, a vacuum degree of 60 kPa, heating at 190°C, and pressurization at 0.1 MPa for 3 seconds. Next, as shown in FIG. 8(D), the electrolyte 20 is injected into the region surrounded by the film 11. Then, while performing evacuation, heating, and pressurization, the remaining one side 11d of the film 11 is sealed as shown in FIG. 8(E). These operations are performed in an environment where oxygen is excluded, such as using a glove box. The evacuation can be performed using a degassing sealer, a liquid injection sealer, or the like. Also, by sandwiching the film 11 with two heatable bars provided in the sealer, heating and pressurization can be performed to seal. Each condition can be, for example, a vacuum degree of 60 kPa, heating at 190°C, and pressurization at 0.1 MPa for 3 seconds. Next, as shown in FIG. 8(D), the electrolyte 20 is injected into the region surrounded by the film 11. Then, while performing evacuation, heating, and pressurization, the remaining one side 11d of the film 11 is sealed as shown in FIG. 8(E). These operations are performed in an environment where oxygen is excluded, such as using a glove box. The evacuation can be performed using a degassing sealer, a liquid injection sealer, or the like. Also, by sandwiching the film 11 with two heatable bars provided in the sealer, heating and pressurization can be performed to seal. Each condition can be, for example, a vacuum degree of 60 kPa, heating at 190°C, and pressurization at 0.1 MPa for 3 seconds. Next, as shown in FIG. 8(D), the electrolyte 20 is injected into the region surrounded by the film 11. Then, while performing evacuation, heating, and pressurization, the remaining one side 11d of the film 11 is sealed as shown in FIG. 8(E). These operations are performed in an environment where oxygen is excluded, such as using a glove box. The evacuation can be performed using a degassing sealer, a liquid injection sealer, or the like. Also, by sandwiching the film 11 with two heatable bars provided in the sealer, heating and pressurization can be performed to seal. Each condition can be, for example, a vacuum degree of 60 kPa, heating at 190°C, and pressurization at 0.1 MPa for 3 seconds. Next, as shown in FIG. 8(D), the electrolyte 20 is injected into the region surrounded by the film 11. Then, while performing evacuation, heating, and pressurization, the remaining one side 11d of the film 11 is sealed as shown in FIG. 8(E). These operations are performed in an environment where oxygen is excluded, such as using a glove box. The evacuation can be performed using a degassing sealer, a liquid injection sealer, or the like. Also, by sandwiching the film 11 with two heatable bars provided in the sealer, heating and pressurization can be performed to seal. Each condition can be, for example, a vacuum degree of 60 kPa, heating at 190°C, and pressurization at 0.1 MPa for 3 seconds. Next, as shown in FIG. 8(D), the electrolyte 20 is injected into the region surrounded by the film 11. Then, while performing evacuation, heating, and pressurization, the remaining one side 11d of the film 11 is sealed as shown in FIG. 8(E). These operations are performed in an environment where oxygen is excluded, such as using a glove box. The evacuation can be performed using a degassing sealer, a liquid injection sealer, or the like. Also, by sandwiching the film 11 with two heatable bars provided in the sealer, heating and pressurization can be performed to seal. Each condition can be, for example, a vacuum degree of 60 kPa, heating at 190°C, and pressurization at 0.1 MPa for 3 seconds. Next, as shown in FIG. 8(D), the electrolyte 20 is injected into the region surrounded by the film 11. Then, while performing evacuation, heating, and pressurization, the remaining one side 11d of the film 11 is sealed as shown in FIG. 8(E). These operations are performed in an environment where oxygen is excluded, such as using a glove box. The evacuation can be performed using a degassing sealer, a liquid injection sealer, or the like. Also, by sandwiching the film 11 with two heatable bars provided in the sealer, heating and pressurization can be performed to seal. Each condition can be, for example, a vacuum degree of 60 kPa, heating at 190°C, and pressurization at 0.1 MPa for 3 seconds.

[0108] Next, it is preferable to perform an aging process on the secondary battery obtained in the above process. By ring processing, the film formed at the interface between the electrode and the electrolyte can be controlled to activate the active material. This is possible.

[0109] Furthermore, the secondary battery that has undergone the aging process may be unsealed once, the gas generated by aging may be removed, and then the electrolyte may be added and resealed. If gas exists between the positive and negative electrodes, the battery reaction will be biased and become a cause of deterioration. Therefore, by removing the gas and resealing, deterioration can be suppressed.

[0110] In this embodiment, since the rectangular separator 13, the positive electrode current collector 12, the negative electrode current collector 14, and the film 11 are used for the description, the method of sealing the four sides in order has been described. However, one aspect of the present invention is not limited to this. When manufacturing a secondary battery other than rectangular, the order and method of sealing can be changed as appropriate.

[0111] In this way, by having a current collector with a meandering pattern and partially removing the positive electrode active material layer at the root of the meandering pattern, a bent battery can be realized.

[0112] This embodiment can be freely combined with Embodiment 1.

[0113] (Embodiment 3) In this embodiment, an example of an electronic device incorporating the lithium-ion secondary battery obtained by using Embodiment 1 or Embodiment 2 is shown.

[0114] The secondary battery obtained by using Embodiment 1 or Embodiment 2 has a partially removed active material layer, and can relieve the stress applied when the secondary battery is bent. This secondary battery is attached to a support structure having a curved surface, and is attached to the curved surface portion of the region with a large radius of curvature of the support structure. ​​​​​​​​​​It can be deformed into a following flexible shape.

[0115] As an electronic device to which a power storage device having a flexible shape is applied, for example, a head-mounted display device such as a display or a goggle-type display (also referred to as a TV or a television receiver), a personal computer such as a desktop type or a notebook type, a monitor for a computer and the like, a digital camera, a digital video camera, a digital photo frame, an electronic notebook, an electronic book, an electronic translator, a toy, a voice input device such as a microphone, an electric shaver, an electric toothbrush, a high-frequency heating device such as a microwave oven, an electric rice cooker, an electric washing machine, an electric cleaner, a water heater, a fan, a hair dryer, an air conditioning equipment such as a humidifier, a dehumidifier or an air conditioner a dishwasher, a dish dryer, a clothes dryer, a futon dryer, an electric refrigerator, an electric freezer, an electric refrigerator-freezer, a freezer for DNA storage, a flashlight, a power tool, a smoke detector, an alarm device such as a gas alarm device or a crime prevention alarm device, an industrial robot, a hearing aid, a cardiac pacemaker, an X-ray imaging device, a radiation measuring device, a health device or a medical device such as an electric massager or a dialysis device, a mobile phone (also referred to as a mobile phone, a mobile phone device), a portable game machine, a portable information terminal, a lighting device, headphones, a stereo, a remote controller, a clock such as a table clock or a wall clock, a cordless telephone handset a transceiver, a pedometer, a calculator, a portable or stationary audio reproduction device such as a digital audio player, a large game machine such as a pachinko machine, etc. can be mentioned.

[0116] In addition, it is also possible to incorporate a power storage device having a flexible shape along the inner wall or outer wall of a house or a building, or along the curved surface of the interior or exterior of an automobile.

[0117] Figure 9(A) shows an example of a mobile phone. The mobile phone 7400 includes a display unit 7402 incorporated in a housing 7401, as well as operation buttons 7403, an external connection port 7404, a speaker 7405, a microphone 7406, etc. Note that the mobile phone 7400 has a power storage device 7407. In addition to the display unit 7402 incorporated in the housing 7401, it is equipped with operation buttons 7403, an external connection port 7404, a speaker 7405, a microphone 7406, etc. Note that the mobile phone 7400 has a power storage device 7407.

[0118] Figure 9(B) shows a state in which the mobile phone 7400 is bent. When the mobile phone 7400 is deformed by an external force and bent as a whole, the power storage device 7407 provided inside it is also bent. When the mobile phone 7400 is deformed by an external force and bent as a whole, the power storage device 7407 provided inside it is also bent. Also, at that time, the state of the bent power storage device 7407 is shown in Figure 9(C). The power storage device 7407 is a laminated structure battery (also called a stacked structure battery or a film-packaged battery). Also, at that time, the state of the bent power storage device 7407 is shown in Figure 9(C). The power storage device 7407 is a laminated structure battery (also called a stacked structure battery or a film-packaged battery). The power storage device 7407 is fixed in the bent state. Note that the power storage device 7407 has a lead electrode 7408 electrically connected to a current collector 7409. The power storage device 7407 has a lead electrode 7408 electrically connected to a current collector 7409. For example, embossing is performed on the film of the exterior body of the power storage device 7407, and it has a configuration with high reliability in the state where the power storage device 7407 is bent. Furthermore, the mobile phone 7400 may be provided with a slot for inserting a SIM card and a connector portion for connecting a USB device such as a USB memory. Furthermore, the mobile phone 7400 may be provided with a slot for inserting a SIM card and a connector portion for connecting a USB device such as a USB memory.

[0119] Figure 9(D) shows an example of a bendable mobile phone. If it is bent into a shape that can be wound around the forearm, it can be made into the bangle-type mobile phone shown in Figure 9(E). The mobile phone 7100 includes a housing 7101, a display unit 7102, operation buttons 7103, and a power storage device 7104. If it is bent into a shape that can be wound around the forearm, it can be made into the bangle-type mobile phone shown in Figure 9(E). The mobile phone 7100 includes a housing 7101, a display unit 7102, operation buttons 7103, and a power storage device 7104. Also, Figure 9(F) shows the state of the power storage device 7104 that can be bent. When the power storage device 7104 is bent and worn on the user's arm, the housing deforms and the power storage device 7104 When the power storage device 7104 is bent and worn on the user's arm, the housing deforms and the power storage device 7104​​ Part or all of the curvature of 4 changes. Specifically, the radius of curvature is 10 mm or more and 150 mm Within the following range, part or all of the main surface of the housing or the power storage device 7104 changes. Note that , the power storage device 7104 has a lead electrode 7105 electrically connected to the current collector 7106 . For example, a plurality of unevennesses are formed on the surface of the film of the exterior body of the power storage device 7104 by pre ssing, and the power storage device 7104 has a configuration that can maintain high reliability even when bent with a changing curvature a large number of times. Furthermore, the mobile phone 7100 has a slot for inserting a SIM card , a connector section for connecting a USB device such as a USB memory, etc. . Also, when the central portion of the mobile phone shown in FIG. 9(D) is bent, it can be shaped as shown in FIG. 9(G ). Also, by further bending the central portion of the mobile phone , the mobile phone can be miniaturized so that the ends of the mobile phone overlap as shown in FIG. 9(H) and can be sized to fit into the user's pocket or the like. Thus, the mobile phone shown in FIG. 9(D) is a device that can change into a plurality of shapes, and in order to realize it, at least the housing 710 1, the display unit 7102, and the power storage device 7104 desirably have flexibility .

[0120] Also, FIG. 10(A) shows an example of a vacuum cleaner. By providing a secondary battery in the vacuum cleaner, it can be cordless, and since a dust collection space for sucking and storing dust is secured inside the vacuum cleaner , the smaller the space occupied by the power storage device 7604, the more preferable. Therefore, it is useful to dispose a thin power storage device 7604 that can be bent between the outer surface and the dust collection space .

[0121] ​​The vacuum cleaner 7600 is provided with an operation button 7603 and a power storage device 7604. Also, FIG. 10 (B) shows the state of the power storage device 7604 that can be bent. The power storage device 7604 has been embossed on the film of the exterior body, and has a configuration with high reliability in the state where the power storage device 7604 is bent. The power storage device 7604 has a lead electrode 7 601 electrically connected to the negative electrode and a lead electrode 7602 electrically connected to the positive electrode.

[0122] Also, as an example of a power storage device in which one lead electrode is exposed on each of the short sides of the exterior body, FIG. 10(C) shows the state of the power storage device 7605 that can be bent. The power storage device 76 05 has a configuration in which a current collector or a lead electrode is exposed on each of the two short sides of the exterior body. If the film of the exterior body of the power storage device 7605 is also embossed, it can be bent and has high reliability.

[0123] The thin power storage device 7604 can be manufactured using the method for manufacturing a secondary battery shown in Embodiment 1 or Embodiment 2.

[0124] The thin power storage device 7604 has a laminate structure and is bent and fixed. Also, the vacuum cleaner 7600 has a display unit 7606 that displays the remaining power of the thin power storage device 7604 and the like, and the display surface is also curved in accordance with the shape of the outer surface of the vacuum cleaner. The display unit 7606 is provided. Also, the vacuum cleaner has a connection cord for connecting to an outlet, and if sufficient power is charged in the thin power storage device 76 04, the vacuum cleaner can be used by disconnecting the connection cord. Also, the thin power storage device 7604 may be charged wirelessly without using a connection cord.

[0125] ​​​​​​​​ In addition, when a bendable power storage device is mounted on a vehicle, next-generation clean energy vehicles such as hybrid electric vehicles (HEVs), electric vehicles (EVs), or plug-in hybrid electric vehicles (PHEVs) can be realized. Also, power storage devices that can be bent can be mounted on mobile bodies such as agricultural machinery, motorized bicycles including electric assist bicycles, motorcycles, electric wheelchairs, electric carts, small or large ships, submarines, aircraft such as fixed-wing aircraft and rotary-wing aircraft, rockets, artificial satellites, space exploration vehicles and planetary exploration vehicles, and spaceships.

[0126] In FIG. 11, a vehicle using one aspect of the present invention is illustrated. The automobile 8100 shown in FIG. 11(A) is an electric vehicle that uses an electric motor as a power source for traveling. Alternatively, it is a hybrid vehicle that can appropriately select and use an electric motor and an engine as power sources for traveling. When a secondary battery having a laminate structure is mounted on a vehicle, a battery module in which a plurality of secondary batteries having a laminate structure are integrated is installed at one or a plurality of locations. By using one aspect of the present invention, the power storage device itself can be reduced in size and weight. For example, a power storage device having a curved surface can be provided inside a tire to realize a vehicle with a long cruising range. In addition, power storage devices having various shapes can be arranged in the gaps of the vehicle, ensuring the space in the trunk and the passenger space inside the vehicle. Also, the automobile 8100 has a power storage device. The power storage device can not only drive the electric motor but also supply power to light-emitting devices such as headlights 8101 and room lights (not shown).

[0127] In addition, the power storage device can supply power to displays such as the speedometer and tachometer of the automobile 8100. Power can be supplied to the device. Also, the power storage device can supply power to semiconductor devices such as the navigation system of the vehicle 8100.

[0128] The vehicle 8200 shown in Fig. 11(B) can be charged by receiving power supply from external charging facilities by means of a plug-in type, a non-contact power supply method, etc. Fig. 11(B) shows a state in which charging is being performed from the ground-mounted charging device 8021 to the power storage device mounted on the vehicle 8200 via the cable 8022. When charging, charging methods, connector specifications, etc. may be appropriately performed in a predetermined manner such as CHAdeMO (registered trademark) or Combo. The charging device 8021 may be a charging station provided in a commercial facility, or may also be a household power supply. For example, by means of plug-in technology, the power storage device mounted on the vehicle 8200 can be charged by power supply from the outside. Charging can be performed by converting AC power into DC power via a conversion device such as an AC-DC converter.

[0129] Also, although not shown, a power receiving device can be mounted on the vehicle, and power can be supplied non-contact from a power transmission device on the ground for charging. In the case of this non-contact power supply method, by incorporating the power transmission device into the road or outer wall, charging can be performed not only while the vehicle is stopped but also while it is running. Also, using this non-contact power supply method, power can be transmitted and received between two vehicles. Furthermore, a solar cell may be provided on the exterior of the vehicle to charge the power storage device when the vehicle is stopped or running. For such non-contact power supply, an electromagnetic induction method or a magnetic field resonance method can be used.

[0130] According to one aspect of the present invention, since the power storage device can be bent, the degree of freedom in the installation location of the power storage device is increased, and vehicle design of a vehicle can be efficiently performed. Further, according to one aspect of the present invention, the characteristics of the power storage device can be improved, and thus the power storage device itself can be reduced in size and weight. If the power storage device itself can be reduced in size and weight, it contributes to weight reduction of the vehicle, and thus the cruising range can be improved. Further, the power storage device mounted on the vehicle can also be used as a power supply source other than the vehicle. In this case, it is possible to avoid using a commercial power supply at the peak of power demand. This embodiment can be freely combined with Embodiment 1 or 2. The content described in one embodiment (even a part of the content) can be applied to, combined with, or replaced with the content described in another part of the same embodiment (even a part of the content), and / or the content described in one or more other embodiments (even a part of the content). Note that the content described in the embodiments refers to the content described using various figures in each embodiment or the content described using the text described in the specification. Note that a figure (even a part thereof) described in one embodiment can be combined with another part of the figure, another figure (even a part thereof) described in the same embodiment, and / or a figure (even a part thereof) described in one or more other embodiments to form more figures.

[0131]

[0132]

[0133]

[0134]

[0135] In addition, regarding the contents not specified in the drawings or text in the specification, Alternatively, the upper limit of a certain value may be set. If a numerical range is listed, such as a lower limit, you can narrow the range arbitrarily. Or, by excluding one point within the scope, a mode of the invention that excludes a part of the scope is specified. As a result, for example, the prior art can be considered to be within the technical scope of one aspect of the present invention. It may be stipulated that no entry will be allowed.

[0136] As another specific example, for a certain value, for example, "a certain voltage is 3 V or more and 10 V 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." Or, For example, it is possible to define one aspect of the invention as excluding cases where a certain voltage is 13 V or higher. For example, the invention may be stipulated that the voltage is between 5V and 8V. It is possible. For example, it is also possible to specify the invention as having a voltage of approximately 9V. For example, the voltage is between 3V and 10V, but does not include the case where the voltage is 9V. It is also possible to define the invention as "within such a range." Even if it is described that "it is preferable that these conditions are satisfied" or "it is preferable that these conditions are satisfied," , Certain values are not limited to those descriptions. That is, "preferably", "preferably", etc. However, even if the following description is given, the present invention is not necessarily limited to the above description.

[0137] As another specific example, for a certain value, for example, "It is preferable that a certain voltage is 10 V" Assume that it is described as "is". In that case, for example, one aspect of the invention can be defined as excluding the case where a certain voltage is -2V or more and 1V or less. Or, for example, one aspect of the invention can be defined as excluding the case where a certain voltage is 13V or more.

[0138] As another specific example, regarding the properties of a certain substance, assume that it is described as "a certain film is an insulating film". In that case, for example, one aspect of the invention can be defined as excluding the case where the insulating film is an organic insulating film. Or, for example, one aspect of the invention can be defined as excluding the case where the insulating film is an inorganic insulating film. Or, for example, one aspect of the invention can be defined as excluding the case where the film is a conductive film. Or, for example, one aspect of the invention can be defined as excluding the case where the film is a semiconductor film.

[0139] As another specific example, regarding a certain laminated structure, assume that it is described as "a certain film is provided between film A and film B". In that case, for example, the invention can be defined as excluding the case where the film is a multilayer film of four or more layers. Or, for example, the invention can be defined as excluding the case where a conductive film is provided between film A and that film. Coming.

[0140] Note that in this specification, etc., for all terminals of active elements (such as transistors and diodes), passive elements (such as capacitive elements and resistive elements), etc., even if the connection destination is not specified, a person skilled in the art may be able to constitute one aspect of the invention. That is, the connection ​​​​​​​Even without specifying the prior, one aspect of the invention can be said to be clear. And when the content of the connection destination is specified in this specification etc., there may be a case where it is possible to determine that one aspect of the invention that does not specify the connection destination is described in this specification etc. In particular, when there can be multiple cases of the connection destination of the terminal, there is no need to limit the connection destination of the terminal to a specific location. Therefore, for some terminals of active elements (such as transistors, diodes, etc.) and passive elements (such as capacitive elements, resistive elements, etc.), it may be possible to constitute one aspect of the invention by specifying their connection destinations. In this specification etc., when the content is described, there may be a case where it is possible to determine that one aspect of the invention that does not specify the connection destination is described in this specification etc. In particular, when there can be multiple cases of the connection destination of the terminal, there is no need to limit the connection destination of the terminal to a specific location. Therefore, for some terminals of active elements (such as transistors, diodes, etc.) and passive elements (such as capacitive elements, resistive elements, etc.), it may be possible to constitute one aspect of the invention by specifying their connection destinations. Thus, for some terminals of active elements (such as transistors, diodes, etc.) and passive elements (such as capacitive elements, resistive elements, etc.), it may be possible to constitute one aspect of the invention by specifying their connection destinations. In this specification etc., for a certain circuit, at least if the connection destination is specified, a person skilled in the art may be able to specify the invention. Or, for a certain circuit, at least if the function is specified, a person skilled in the art may be able to specify the invention. That is, it can be said that one aspect of the invention is clear if the function is specified. And when one aspect of the invention with the function specified is determined to be described in this specification etc.,

[0141] Therefore, for a certain circuit, even if the function is not specified, as long as the connection destination is specified, it is disclosed as one aspect of the invention and it is possible to constitute one aspect of the invention. Or, for a certain circuit, even if the connection destination is not specified, as long as the function is specified, it is disclosed as one aspect of the invention and it is possible to constitute one aspect of the invention. That is, it can be said that one aspect of the invention is clear if the function is specified. And when one aspect of the invention with the function specified is determined to be described in this specification etc., Therefore, for a certain circuit, even if the function is not specified, as long as the connection destination is specified, it is disclosed as one aspect of the invention and it is possible to constitute one aspect of the invention. Or, for a certain circuit, even if the connection destination is not specified, as long as the function is specified, it is disclosed as one aspect of the invention and it is possible to constitute one aspect of the invention. Therefore, for a certain circuit, even if the function is not specified, as long as the connection destination is specified, it is disclosed as one aspect of the invention and it is possible to constitute one aspect of the invention. Or, for a certain circuit, even if the connection destination is not specified, as long as the function is specified, it is disclosed as one aspect of the invention and it is possible to constitute one aspect of the invention. In this specification etc., in a figure or text described in a certain embodiment, it is possible to extract a part of it to constitute one aspect of the invention. Therefore, In this specification etc., in a figure or text described in a certain embodiment, it is possible to extract a part of it to constitute one aspect of the invention. Therefore,

[0142] In this specification etc., in a figure or text described in a certain embodiment, it is possible to extract a part of it to constitute one aspect of the invention. Therefore, In this specification etc., in a figure or text described in a certain embodiment, it is possible to extract a part of it to constitute one aspect of the invention. Therefore, If there is a figure or text describing a certain part, the content extracted from a part of the figure or text is also disclosed as an aspect of the invention and can constitute an aspect of the invention. And it can be said that an aspect of the invention is clear. Therefore, for example, in a drawing or text in which one or more active elements (such as transistors, diodes, etc.), wirings, passive elements (such as capacitive elements, resistive elements, etc.), 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 of it can be extracted to constitute an aspect of the invention. For example, from a circuit diagram composed of N (N is an integer) circuit elements (such as transistors, capacitive elements, etc.), M ( M is an integer and M < N) circuit elements (such as transistors, capacitive elements, etc.) are extracted, it is possible to constitute an 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, it is possible to constitute an aspect of the invention. As yet another example, from a flowchart composed of N (N is an integer) elements, M ( M is an integer and M < N) elements are extracted, it is possible to constitute an aspect of the invention. As yet another example, from a text stating that "A has B, C, D, E, or F", some elements are arbitrarily extracted to form aspects of the invention such as "A has B and E", "A has E and F", "A has C, E, and F", or "A has B, C, D, and E", etc. It is possible. For example, from a circuit diagram composed of N (N is an integer) circuit elements (such as transistors, capacitive elements, etc.), M ( M is an integer and M < N) circuit elements (such as transistors, capacitive elements, etc.) are extracted, it is possible to constitute an aspect of the invention. Another example is that from a cross-sectional view composed of N (N is an integer) layers, M ( M is an integer and M < N) layers are extracted, it is possible to constitute an aspect of the invention. Still another example is that from a flowchart composed of N (N is an integer) elements, M ( M is an integer and M < N) elements are extracted, it is possible to constitute an aspect of the invention. Further, from a text stating that "A has B, C, D, E, or F", some elements are arbitrarily extracted to form aspects of the invention such as "A has B and E", "A has E and F", "A has C, E, and F", or "A has B, C, D, and E", etc. It is possible to constitute an aspect of the invention. Furthermore, for example, from a text stating that "A has B, C, D, E, or F", some elements are arbitrarily extracted to form aspects of the invention such as "A has B and E", "A has E and F", "A has C, E, and F", or "A has B, C, D, and E", etc. It is possible to constitute an aspect of the invention. For example, from a text stating that "A has B, C, D, E, or F", some elements are arbitrarily extracted to form aspects of the invention such as "A has B and E", "A has E and F", "A has C, E, and F", or "A has B, C, D, and E", etc. It is possible to constitute an aspect of the invention. It should be noted that in this specification, etc., in a figure or text described in a certain embodiment

[0143] If there is a figure or text describing a certain part, the content extracted from a part of the figure or text is also disclosed as an aspect of the invention and can constitute an aspect of the invention. And it can be said that an aspect of the invention is clear. Therefore, for example, in a drawing or text in which one or more active elements (such as transistors, diodes, etc.), wirings, passive elements (such as capacitive elements, When at least one specific example is described, it is easily understood by those skilled in the art. Therefore, in one embodiment, when at least one specific example is described in a figure or text, the upper concept of that specific example is also disclosed as one aspect of the invention and can form one aspect

[0144] of the invention. And it can be said that one aspect of the invention is clear. Note that in this specification, etc., at least the content described in the figures (even a part of the figures) is disclosed as one aspect of the invention and can form one aspect of the invention. Therefore, for a certain content, if it is described in the figures, even if it is not described in the text, that content is disclosed as one aspect of the invention and can

[0145] form one aspect of the invention. Similarly, for a figure extracted from a part of the figures, it is also disclosed as one

[0146] <Positive electrode active material removal sample> The secondary battery with the positive electrode active material

[0147] partially removed was fabricated as follows. LiCoO2 was used as the positive electrode active material, and The amounts were as follows: LiCoO₂ was 90 wt%, AB was 5 wt%, and PVDF was 5 wt%. For the positive electrode current collector, aluminum with a thickness of 20 μm was used, and a mixture of LiCoO₂, AB, and PVDF was coated on one side of the positive electrode current collector to form a positive electrode active material layer. Then, by laser light irradiation, two portions of the positive electrode active material layer, at narrow regions with widths for connection to the electrode lead in subsequent processes and at narrow portions of the meandering portion, were selectively removed. Further, laser processing was performed to delineate the contour of the current collector having the meandering portion, and both the positive electrode active material layer and the metal foil were selectively removed to fabricate a positive electrode current collector and a positive electrode active material layer having the shape shown in Fig. 6(A). For the negative electrode active material, graphite was used, and thereto, vapor-grown carbon fiber (VGCF (registered trademark)), carboxymethyl cellulose (CMC), and styrene-butadiene rubber (SBR) were mixed as a conductive assistant and a binder. The mixing ratios were as follows: graphite was 96 wt%, VGCF was 1 wt%, CMC was 1 wt%, and SBR was 2 wt%. For the negative electrode current collector, copper with a thickness of 18 μm was used. A mixture of graphite, VGCF, CMC, and SBR was coated on one side of the negative electrode current collector to form a negative electrode active material layer.

[0148] And then, by laser light irradiation, the negative electrode active material in a narrow region with a width for connection to the electrode lead in subsequent processes was selectively removed. Further, laser processing was performed to delineate the contour of the current collector having the meandering portion, and both the negative electrode active material layer and the metal foil were selectively removed to fabricate a negative electrode current collector and a negative electrode active material layer having the shape shown in Fig. 6(C). For the electrolytic solution, in an organic solvent mixed at EC:DEC:EMC = 3:6:1 (weight ratio),

[0149]

[0150]

[0151] ​​​​​​​​​​​​​1.2 mol / L of LiPF6 was dissolved, and propane sultone (PS) at 0 .5 wt% and vinylene carbonate (VC) at 0.5 wt% were added and used.

[0152] Polypropylene was used for the separator.

[0153] An aluminum laminate film was used for the exterior body.

[0154] One piece each of the above positive electrode current collector and negative electrode current collector, together with the electrolytic solution, separator and exterior body, were used to fabricate a secondary battery according to the fabrication method shown in Embodiment 1, and a sample with the positive electrode active material removed was obtained.

[0155] <Sample without removal treatment> The secondary battery without removing the positive electrode active material was fabricated in the same manner as the sample with the positive electrode active material removed, except that the positive electrode active material layer at the narrow part of the meandering portion was not removed in the process of laser light irradiation.

[0156] <Charging> The sample with the positive electrode active material removed and the sample without the removal treatment were charged under the same conditions. The charging conditions were 4.1 V, rate 0.3C, CCCV, and cut-off current 0.01C. Also, the charging was carried out at 25°C.

[0157] <Comparison of electrodes after charging> Photographs of the positive electrode current collector of the sample with the positive electrode active material removed after charging are shown in Fig. 12(A), and the photograph of the negative electrode current collector is shown in Fig. 12(B). The portion circled in Fig. 12(A) is the narrow part of the meandering portion where the positive electrode active material has been removed. The portion circled in Fig. 12(B) is the portion that overlaps with the narrow part of the meandering portion of the positive electrode current collector.

[0158] Also, photographs of the positive current collector of the sample without the removal treatment after charging are shown in Fig. 12(C), and those of the negative current collector are shown in Fig. 12(D). The portion circled in Fig. 12(C) is the narrow part of the width of the meandering portion where the positive electrode active material was not removed. The portion circled in Fig. 12(D) overlaps with the narrow part of the width of the meandering portion of the positive current collector.

[0159] Also, the charged negative current collector was observed using an SEM (scanning electron microscope). An electron micrograph of the negative electrode active material closest to the narrow part of the width of the meandering portion of the positive current collector of the negative current collector, that is, the negative electrode active material closest to the slit, is shown in Fig. 13. Fig. 13(A) is an electron micrograph of the negative current collector of the positive electrode active material removal sample, and Fig. 13(B) is an electron micrograph of the sample without the removal treatment.

[0160] In the positive electrode active material removal sample of Fig. 13(A), no abnormality was observed on the surface of the negative electrode active material. However, in the sample without the removal treatment of Fig. 13(B), needle-like products were observed on the surface of the negative electrode active material, and it was found that lithium was deposited on the surface of the negative electrode active material.

[0161] From the above results, it became clear that by partially removing the positive electrode active material, lithium deposition on the surface of the negative electrode active material can be suppressed.

Explanation of symbols

[0162] 11 Film 12 Positive current collector 13 Separator 14 Negative current collector 15 Sealing layer 16a Lead electrode 16b Lead electrode 18 Positive electrode active material layer 18a Positive electrode active material layer 18b Positive electrode active material layer 18c Positive electrode active material layer​​​​ 18d positive electrode active material layer 18e positive electrode active material layer 18f positive electrode active material layer 18g positive electrode active material layer 18h positive electrode active material layer 18i positive electrode active material layer 19 negative electrode active material layer 20 electrolyte 40 secondary battery 80 roll 90 roll 7100 mobile phone 7101 housing 7102 display unit 7103 operation button 7104 power storage device 7105 lead electrode 7106 current collector 7400 mobile phone 7401 housing 7402 display unit 7403 operation button 7404 external connection port 7405 speaker 7406 microphone 7407 power storage device 7408 lead electrode 7409 current collector 7600 vacuum cleaner 7601 lead electrode 7602 lead electrode 7603 operation button 7604 power storage device 7605 power storage device 7606 display unit 8021 charger 8022 cable 8100 automobile 8101 headlight 8200 automobile

Claims

1. A current collector, a first active material layer on the current collector, a second active material layer on the current collector, and having, the first active material layer is separated from the second active material layer, a lithium ion secondary battery.

2. A current collector, a first active material layer on the current collector, a second active material layer on the current collector, a third active material layer on the current collector, and having, the first to third active material layers are separated from each other, the distance between the first active material layer and the second active material layer is equal to the distance between the second active material layer and the third active material layer, a lithium ion secondary battery.

3. A current collector, a first active material layer on the current collector, a second active material layer on the current collector, a third active material layer on the current collector, and having, the first to third active material layers are separated from each other, the distance between the first active material layer and the second active material layer is different from the distance between the second active material layer and the third active material layer, a lithium ion secondary battery.

4. A current collector, a first active material layer on one surface side of the current collector, a second active material layer on one surface side of the current collector, a third active material layer on one surface side of the current collector, a fourth active material layer on the other surface side of the current collector, a fifth active material layer on the other surface side of the current collector, a sixth active material layer on the other surface side of the current collector, and having, the first to third active material layers are separated from each other, the fourth to sixth active material layers are separated from each other, a lithium ion secondary battery.

5. A current collector, a first active material layer on one surface side of the current collector, a second active material layer on one surface side of the current collector, a third active material layer on one surface side of the current collector, a fourth active material layer on the other surface side of the current collector, a fifth active material layer on the other surface side of the current collector, a sixth active material layer on the other surface side of the current collector, and having, the first to third active material layers are separated from each other, the fourth to sixth active material layers are separated from each other, in a cross-sectional view, the second active material layer has a region overlapping a part of the fourth active material layer and a part of the fifth active material layer, a lithium ion secondary battery.

6. In any one of Claims 1 to 5, the first active material layer and the second active material layer each have a positive electrode active material, a lithium ion secondary battery.

7. In any one of Claims 1 to 5, The first active material layer and the second active material layer each have a negative electrode active material, a lithium ion secondary battery.

Images