Method for manufacturing electronic device

Abstract

To provide a power storage device which is less in the degradation of charge / discharge characteristics owing to a heat treatment, or to provide a power storage device which is high in safety against the heat treatment.SOLUTION: A power storage device comprises a positive electrode, a negative electrode, a separator, an electrolytic solution, and an outer packaging body. The separator is located between the positive and negative electrodes. The separator includes a polyphenylene sulfide or a regenerated cellulose fiber produced by a solvent-spinning method. The electrolytic solution includes a solute and two or more kinds of solvent. The solute includes LiBETA. The two or more kinds of solvent include propylene carbonate.SELECTED DRAWING: Figure 1

Description

Technical Field

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

[0002] Note that one aspect of the present invention is not limited to the above technical field. One aspect of the invention disclosed in this specification etc. relates to an article, a method, or a manufacturing method. One aspect of the present invention relates to a process, a machine, a manufacture, or a composition (composition of matter). Therefore, as the technical field of one aspect of the invention more specifically disclosed in this specification, semiconductor devices, display devices , light-emitting devices, power storage devices, storage devices, imaging devices, their driving methods, or their manufacturing methods can be cited as an example.

[0003] Note that in this specification, the power storage device refers to all elements and devices having a power storage function. For example, it includes power storage devices (also referred to as secondary batteries) such as lithium ion secondary batteries, lithium ion capacitors, and electric double layer capacitors.

Background Art

[0004] In recent years, the development of various power storage devices such as lithium ion secondary batteries, lithium ion capacitors, and air batteries has been actively carried out. In particular, lithium ion secondary batteries with high output and high energy density have rapidly expanded their demand along with the development of the semiconductor industry in portable information terminals such as mobile phones, smartphones, or notebook computers , portable music players, digital cameras, medical devices, or next-generation clean energy vehicles such as hybrid vehicles (HEV), electric vehicles (EV), or plug-in hybrid vehicles (PHEV), and can be repeatedly charged ​It has become essential in the modern information society as a source of electrical energy supply.

[0005] Thus, lithium-ion secondary batteries are used in various fields or applications. Among them the characteristics required for lithium-ion secondary batteries include high energy density, high cycle characteristics and safety in various operating environments.

[0006] Also, a lithium-ion secondary battery has at least a positive electrode, a negative electrode, and an electrolyte ([[]] Patent Document 1).

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0008] When a lithium-ion secondary battery is mounted on an electronic device such as a wearable device or a portable information terminal, it needs to withstand the heat treatment associated with the processing of the electronic device. In particular, when the housing of the electronic device is integrally formed with the lithium-ion secondary battery, it needs to have heat resistance equal to or higher than the manufacturing temperature of the housing.

[0009] One aspect of the present invention is to provide an energy storage device with less deterioration of charge / discharge characteristics due to heat treatment as one of the problems.

[0010] Another aspect of the present invention is to provide an energy storage device with high safety in heat treatment as one of the problems.

[0011] ​​​​​Alternatively, one aspect of the present invention aims to provide a highly flexible power storage device. Also, one aspect of the present invention aims to provide a novel power storage device, electronic device, etc. .

[0012] Note that the description of these problems does not preclude the existence of other problems. Also, one aspect of the present invention does not necessarily need to solve all of these problems. Also, 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

[0013] One aspect of the present invention includes a positive electrode, a negative electrode, a separator, an electrolyte, and an exterior body. The positive electrode includes a positive electrode active material layer and a positive electrode current collector, the negative electrode includes a negative electrode active material layer and a negative electrode current collector, the separator is positioned between the positive electrode and the negative electrode, and the separator includes polyphenylene sulfide or solvent-spun regenerated cellulose fibers. The electrolyte has a solute and two or more solvents, the solute includes LiBETA (lithium bis(pentafluoroethanesulfonyl)amide), and the solvents include propylene carbonate. It is a power storage device.

[0014] Also, the aforementioned power storage device in which the solvents include propylene carbonate and ethylene carbonate is also one aspect of the present invention.

[0015] Also, the aforementioned power storage device in which the negative electrode active material layer includes graphite is also one aspect of the present invention.

[0016] Also, the negative electrode active material layer includes spheroidized natural graphite, and the spheroidized natural graphite has a first region and a second having a region, the first region covering the second region, the first region being less crystalline than the second region The above-described power storage device is also one aspect of the present invention.

[0017] Also, the above-described power storage device in which the positive electrode active material layer contains LiCoO₂ is also one aspect of the present invention.

[0018] Also, the above-described power storage device in which the positive electrode current collector contains aluminum or stainless steel is also one aspect of the present invention.

[0019] Also, a method for manufacturing the above-described power storage device, which includes a heating step at a first temperature for 10 minutes before energization of the power storage device, and the first temperature is 110°C or higher and 190°C or lower, is also one aspect of the present invention.

[0020] One aspect of the present invention has the above-described power storage device, a band, a display panel, and a housing. The power storage device has a positive electrode lead and a negative electrode lead. The positive electrode lead is electrically connected to the positive electrode, the negative electrode lead is electrically connected to the negative electrode, the power storage device is embedded inside the band, and a part of the positive electrode lead and a part of the negative electrode lead protrude from the band. The power storage device has flexibility and is electrically connected to the display panel. The display panel is included in the housing, and the band is connected to the housing and includes a rubber material. It is an electronic device.

[0021] Also, the above-described electronic device in which the rubber material is fluororubber or silicone rubber is also one aspect of the present invention.

Advantages of the Invention

[0022] According to one aspect of the present invention, it is possible to provide a power storage device with less deterioration of charge-discharge characteristics due to heat treatment.

[0023] ​​ Alternatively, according to one aspect of the present invention, a power storage device with high safety in heat treatment can be provided. It is possible.

[0024] Alternatively, according to one aspect of the present invention, a highly flexible power storage device can be provided. Or According to one aspect of the present invention, a novel power storage device, electronic device, etc. can be provided.

[0025] Note that the description of these effects does not prevent the existence of other effects. Note that one aspect of the present invention does not necessarily have to have all of these effects. Note that other effects will naturally become clear from the descriptions in the specification, drawings, claims, etc., and it is possible to extract these other effects from the descriptions in the specification, drawings and claims.

Brief Description of the Drawings

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Embodiments for Carrying Out the Invention

[0027] The embodiments will be described in detail with reference to the drawings. However, the present invention is not limited to the following description. Without departing from the spirit and scope of the present invention, its form and details can be variously changed This is easily understood by those skilled in the art. Therefore, the present invention is not construed as being limited to the description of the embodiments shown below

[0028] In the configuration of the invention described below, the same part or parts having the same function are commonly used with the same reference numeral among different drawings, and the repeated description thereof is omitted. Also, when referring to the same function, the hatching pattern may be the same and may not be particularly labeled

[0029] In addition, the position, size, range, etc. of each component shown in the drawings and the like may not represent the actual position, size, range, etc. for the sake of easy understanding. For this reason, the disclosed invention is not necessarily limited to the position, size, range, etc. disclosed in the drawings and the like

[0030] Note that the terms "film" and "layer" may be interchangeable depending on the case or situation For example, the term "conductive layer" may be changed to the term "conductive film" Or, for example, the term "insulating film" may be changed to the term "insulating layer"

[0031] (Embodiment 1) In this embodiment, a power storage device according to an aspect of the present invention will be described with reference to FIGS. 1 to 11

[0032] A power storage device according to an aspect of the present invention includes a positive electrode, a negative electrode, a separator, an electrolytic solution, and an exterior body

[0033] Note that in this specification and the like, the electrolytic solution is not limited to a liquid and may be a gel or a solid ​​​​

[0034] In order to improve the heat resistance of an electricity storage device, the solute contained in the electrolyte must first be highly stable at high temperatures. For example, lithium hexafluorophosphate, which is widely used as a solute lithium salt, LiPF6 decomposes into LiF and PF5 at high temperatures, but PF5 causes the decomposition of the solvent. It is said that this causes oxidation, and its stability as a solute at high temperatures is thought to be low.

[0035] In view of this, in the power storage device of one embodiment of the present invention, lithium bismuth oxide is used as a solute in the electrolyte. Trifluoroethanesulfonylamide (Li(C2F5SO2)2N, abbreviation: LiBETA It is preferable to use LiBETA. The decomposition temperature of LiBETA is 350℃, and it has high heat resistance. In addition, when aluminum or the like is used for the positive electrode current collector, the surface of the current collector may become This is preferable because it is easy to form a passivation film on the surface and can suppress elution of the positive electrode current collector.

[0036] In order to increase the heat resistance of the electricity storage device, the solvent contained in the electrolyte is selected to have a high boiling point and a high vapor pressure. For example, propylene is a non-aqueous solvent having a boiling point of 242° C. Carbonate (PC) is an example.

[0037] However, when graphite is used as the negative electrode active material, PC does not form a passive film on the graphite surface, and lithium When the ions are inserted between the graphite layers, some of the graphite layers are peeled off from the graphite particles. This may happen.

[0038] Therefore, in the power storage device of one embodiment of the present invention, the electrolyte solution contains two or more types of solvents. The solvents in the electrolyte other than PC form a passive film on the negative electrode surface. Preferably, it has a function. As a solvent contained in the electrolytic solution other than PC, for example, ethylene carbonate (EC), vinylene carbonate (VC), etc. can be mentioned.

[0039] The boiling point of EC is 248 °C, it has high heat resistance and low vapor pressure. Also, depending on the graphite material selected used, the solvent obtained by mixing PC and EC can suppress the peeling of the graphite layer. For example, a mixture of PC and EC at a volume ratio of 1:1 can be used as the solvent. Also, when using graphite for the negative electrode, it is preferable to select a graphite material with reduced intercalation of PC . The power storage device according to one aspect of the present invention uses spherical natural graphite as the negative electrode active material. Spherical natural graphite has a region with low crystallinity on the surface side, and thus there is a possibility of reducing the intercalation of PC.

[0040] An aluminum laminate cell sealed inside with an electrolytic solution in which 1 mol / l of LiBETA is dissolved and PC and EC are mixed at a volume ratio of 1:1 has been confirmed not to expand by heat treatment at 170 °C for 15 minutes. Therefore, the solvent obtained by mixing PC and EC at a volume ratio of 1:1 has high stability at high temperatures and low vapor pressure.

[0041] Also, polyethylene, polypropylene, etc. generally used as separators are vulnerable to heat . At high temperatures, the micropores of the separator may be blocked, and the power storage device may stop operating.

[0042] Therefore, in the power storage device according to one aspect of the present invention, a separator containing polyphenylene sulfide or a separator containing solvent-spun regenerated cellulose fibers is used.

[0043] Separator containing polyphenylene sulfide and solvent-spun regenerated cellulose fibers The separator containing polyphenylene sulfide and solvent-spun regenerated cellulose fibers is excellent in heat resistance and chemical resistance.

[0044] In addition, the separator containing polyphenylene sulfide and the separator containing solvent-spun regenerated cellulose fibers have low reactivity with the electrolytic solution at high temperatures. Therefore, it is possible to suppress the deterioration of output characteristics and charge-discharge cycle characteristics.

[0045] <Configuration example of power storage device> Next, a specific configuration of the power storage device according to one aspect of the present invention will be described.

[0046] FIG. 1(A) shows a power storage device 500 which is a power storage device according to one aspect of the present invention. In FIG. 1(A), although a thin power storage device form is shown as an example of the power storage device 500, the power storage device according to one aspect of the present invention is not limited thereto.

[0047] As shown in FIG. 1(A), the power storage device 500 has a positive electrode 503, a negative electrode 506, a separator 50 7, and an exterior body 509. The power storage device 500 may have a positive electrode lead 510 and a negative electrode lead 5 11. Further, the joint portion 518 is a portion where the outer periphery of the exterior body 509 is joined by thermocompression bonding.

[0048] FIGS. 2(A) and (B) respectively show an example of a cross-sectional view between the dashed-dotted line A1 - A2 in FIG. 1(A). FIGS. 2(A) and (B) show the cross-sectional structures of the power storage device 500 fabricated using one set of the positive electrode 503 and the negative electrode 506.

[0049] As shown in FIGS. 2(A) and (B), the power storage device 500 has a positive electrode 503, a negative electrode 506, a separator 507, an electrolytic solution 508, and an exterior body 509. The separator 507 is the positive electrode 50 It is located between 3 and the negative electrode 506. The interior of the exterior body 509 is filled with the electrolytic solution 508.

[0050] The positive electrode 503 includes a positive electrode active material layer 502 and a positive electrode current collector 501. The negative electrode 506 includes a negative electrode active material layer 505 and a negative electrode current collector 504. The active material layer may be formed on one side or both sides of the current collector. The separator 507 is located between the positive electrode current collector 501 and the negative electrode current collector 504.

[0051] The power storage device may have one or more positive electrodes and negative electrodes respectively. For example, the power storage device can also have a laminated structure composed of a plurality of positive electrodes and a plurality of negative electrodes.

[0052] FIG. 3(A) shows another example of a cross-sectional view between the dashed-dotted line A1 - A2 in FIG. 1(A). Also, FIG. 3(B) shows a cross-sectional view between the dashed-dotted line B1 - B2 in FIG. 1(A).

[0053] FIGS. 3(A) and (B) show the cross-sectional structure of the power storage device 50 0 fabricated using a plurality of sets of the positive electrode 503 and the negative electrode 506. There is no limitation on the number of electrode layers that the power storage device 500 has. When the number of electrode layers is large, a power storage device with a larger capacity can be obtained. Also, when the number of electrode layers is small, it can be made thin and can be a power storage device with excellent flexibility.

[0054] In FIGS. 3(A) and (B), two positive electrodes 5 03 each having a positive electrode active material layer 502 on one side of the positive electrode current collector 501, and two positive electrodes 503 each having a positive electrode active material layer 502 on both sides of the positive electrode current collector 501, and three negative electrodes 506 each having a negative electrode active material layer 505 on both sides of the negative electrode current collector 504 are used as an example. That is, the power storage device 500 has six layers of positive electrode active material layers 502 and six layers of negative electrode active material layers 5 ​​It has 05. In FIGS. 3(A) and (B), although the separator 507 shows an example of a bag shape, it is not limited thereto, and the separator 507 may be strip-shaped or bellows-shaped.

[0055] Also, in FIG. 3, one positive electrode having the positive electrode active material layer 502 on both sides of the positive electrode current collector 501 is preferably replaced with two positive electrodes having the positive electrode active material layer 502 on one side of the positive electrode current collector 501. Similarly, one negative electrode having the negative electrode active material layer 505 on both sides of the negative electrode current collector 504 is preferably replaced with two negative electrodes having the negative electrode active material layer 505 on one side of the negative electrode current collector 504. The power storage device 500 shown in FIG. 4 has the surfaces of the positive electrode current collector 501 where the positive electrode active material layer 502 is not attached facing each other and in contact, and the surfaces of the negative electrode current collector 504 where the negative electrode active material layer 505 is not attached facing each other and in contact. By adopting such a configuration, when the power storage device 500 is bent, the interfaces of the two positive electrode current collectors 501 and the interfaces of the two negative electrode current collectors 504 become sliding surfaces, and the stress generated inside the power storage device 500 can be relieved.

[0056] Next, FIG. 1(B) shows an external view of the positive electrode 503. The positive electrode 503 has the positive electrode current collector 501 and the positive electrode active material layer 502.

[0057] Also, FIG. 1(C) shows an external view of the negative electrode 506. The negative electrode 506 has the negative electrode current collector 504 and the negative electrode active material layer 505.

[0058] Here, the positive electrode 503 and the negative electrode 506 preferably have a tab region in order to electrically connect a plurality of stacked positive electrodes or a plurality of stacked negative electrodes to each other. Also, it is preferable to electrically connect a lead to the tab region.

[0059] As shown in FIG. 1(B), the positive electrode 503 preferably has a tab region 281. A portion of region 281 is preferably welded to the positive electrode lead 510. The tab region 281 is It is preferable that the positive electrode current collector 501 has an exposed area. By welding the positive lead 510 to the area, lower contact resistance can be achieved. FIG. 1B shows an example in which the positive electrode current collector 501 is exposed over the entire area of the tab region 281. 5, the tab region 281 may have a positive electrode active material layer 502 in a part thereof.

[0060] As shown in FIG. 1C, the negative electrode 506 preferably has a tab region 282. A portion of region 282 is preferably welded to negative electrode lead 511. Tab region 282 is It is preferable that the negative electrode current collector 504 has an exposed area. By welding the negative electrode lead 511 to this area, the contact resistance can be made lower. FIG. 1C shows an example in which the negative electrode current collector 504 is exposed over the entire area of the tab region 282. 5, the tab region 282 may have a negative electrode active material layer 505 in a portion thereof.

[0061] In FIG. 1A, an example in which the ends of the positive electrode 503 and the negative electrode 506 are roughly aligned is shown. The electrode 503 may have a portion located outside the end of the negative electrode 506 .

[0062] In the power storage device 500, the area of the negative electrode 506 that does not overlap with the positive electrode 503 is smaller. preferable.

[0063] FIG. 2A shows an example in which the end of the negative electrode 506 is located inside the positive electrode 503. By adopting such a configuration, the negative electrode 506 is entirely overlapped with the positive electrode 503, or the negative electrode 506 is completely overlapped with the positive electrode The area of the region that does not overlap with 503 can be reduced.

[0064] Alternatively, in the power storage device 500, it is preferable that the areas of the positive electrode 503 and the negative electrode 506 are substantially the same. For example, it is preferable that the areas of the positive electrode 503 and the negative electrode 506 facing each other with the separator 507 interposed therebetween are substantially the same. For example, it is preferable that the areas of the positive electrode active material layer 502 and the negative electrode active material layer 505 facing each other with the separator 507 interposed therebetween are substantially the same. For example, as shown in FIGS. 3(A) and 3(B), it is preferable that the area of the surface of the positive electrode 503 on the separator 507 side is substantially the same as the area of the surface of the negative electrode 506 on the separator 507 side.

[0065] For example, as shown in FIGS. 3(A) and 3(B), it is preferable that the area of the surface of the positive electrode 503 on the separator 507 side is substantially the same as the area of the surface of the negative electrode 506 on the separator 507 side. For example, as shown in FIGS. 3(A) and 3(B), it is preferable that the area of the surface of the positive electrode 503 on the separator 507 side is substantially the same as the area of the surface of the negative electrode 506 on the separator 507 side. By making the area of the surface of the positive electrode 503 on the negative electrode 506 side substantially the same as the area of the surface of the negative electrode 506 on the positive electrode 503 side, the region where the negative electrode 506 does not overlap with the positive electrode 503 can be reduced (or ideally eliminated), and the irreversible capacity of the power storage device 500 can be reduced, which is preferable. For example, as shown in FIGS. 3(A) and 3(B), it is preferable that the area of the surface of the positive electrode active material layer 502 on the separator 507 side is substantially the same as the area of the surface of the negative electrode active material layer 505 on the separator 507 side. For example, as shown in FIGS. 3(A) and 3(B), it is preferable that the area of the surface of the positive electrode active material layer 502 on the separator 507 side is substantially the same as the area of the surface of the negative electrode active material layer 505 on the separator 507 side. For example, as shown in FIGS. 3(A) and 3(B), it is preferable that the area of the surface of the positive electrode active material layer 502 on the separator 507 side is substantially the same as the area of the surface of the negative electrode active material layer 505 on the separator 507 side. For example, as shown in FIGS. 3(A) and 3(B), it is preferable that the area of the surface of the positive electrode active material layer 502 on the separator 507 side is substantially the same as the area of the surface of the negative electrode active material layer 505 on the separator 507 side. For example, as shown in FIGS. 3(A) and 3(B), it is preferable that the area of the surface of the positive electrode active material layer 502 on the separator 507 side is substantially the same as the area of the surface of the negative electrode active material layer 505 on the separator 507 side.

[0066] Also, as shown in FIGS. 3(A) and 3(B), it is preferable that the ends of the positive electrode 503 and the ends of the negative electrode 506 are substantially aligned. Also, it is preferable that the ends of the positive electrode active material layer 502 and the ends of the negative electrode active material layer 505 are substantially aligned. Also, it is preferable that the ends of the positive electrode active material layer 502 and the ends of the negative electrode active material layer 505 are substantially aligned.

[0067] Also, in FIG. 2(B), an example is shown in which the end of the positive electrode 503 is located inside the negative electrode 506. With such a configuration, all of the positive electrode 503 can be overlapped with the negative electrode 506, or the positive electrode 503 The area of the region that does not overlap with the negative electrode 506 can be reduced. If the end of the negative electrode 506 is located inside the end of the positive electrode 503, current may concentrate at the end of the negative electrode 506. For example, due to the concentration of current in a part of the negative electrode 506, lithium may precipitate on the negative electrode 506. By reducing the area of the region of the positive electrode 503 that does not overlap with the negative electrode 506, concentration of current in a part of the negative electrode 506 can be suppressed. Thereby, for example, precipitation of lithium on the negative electrode 506 can be suppressed, which is preferable.

[0068] As shown in FIG. 1(A), the positive electrode lead 510 is preferably electrically connected to the positive electrode 503. Similarly, the negative electrode lead 511 is preferably electrically connected to the negative electrode 506. The positive electrode lead 510 and the negative electrode lead 511 are exposed outside the exterior body 509 and function as terminals for obtaining electrical contact with the outside.

[0069] Alternatively, the positive electrode current collector 501 and the negative electrode current collector 504 can also serve as terminals for obtaining electrical contact with the outside. In that case, without using leads, a part of the positive electrode current collector 501 and the negative electrode current collector 504 may be arranged to be exposed outside the exterior body 509.

[0070] Note that it is preferable that a part of the surface of the exterior body 509 has irregularities. By having irregularities on the exterior body 509, the stress applied to the exterior body 509 when the power storage device 500 is bent can be relieved. Therefore, the flexibility of the power storage device 500 can be increased. The above-mentioned irregularities can be formed by performing embossing on the exterior body 509 before assembling the power storage device 500.

[0071] ​​​Here, an explanation of embossing, which is a type of pressing process, will be given.

[0072] FIG. 5 is a cross-sectional view showing an example of embossing. Note that embossing refers to a process of pressing an embossing roll with unevenness on its surface against a film to form unevenness corresponding to the unevenness of the embossing roll on the film. The embossing roll is a roll with a pattern engraved on its surface.

[0073] FIG. 5(A) shows an example of performing embossing on one side of the film 50 used for the exterior body 509.

[0074] In FIG. 5(A), the film 50 is sandwiched between the embossing roll 53 in contact with one side of the film and the roll 54 in contact with the other side, and shows the film 50 in the middle of being fed out in the film advancing direction 60. A pattern is being formed on the film surface by pressure and heat.

[0075] FIG. 5(A) is also called single-sided embossing and is a combination of the embossing roll 53 and the roll 54 (metal roll or elastic roll (such as a rubber roll)).

[0076] Also, FIG. 5(B) shows the film 51 that has been embossed on one side once being sandwiched between the embossing roll 53 and the roll 54 and being fed out in the advancing direction 60. The embossing roll 53 contacts the side of the film 51 that has not been embossed yet and rotates, so the film 51 is embossed on both sides. As in this example, it is also possible to perform embossing on a single film multiple times.

[0077] Figure 5(C) shows an enlarged cross-sectional view of the film 52 with embossing on both sides. . H1 represents the film thickness of the film in the concave or convex portion. Also, H2 is the film thickness at the boundary between the concave portion and the convex portion adjacent to the concave portion, or the film thickness of the film at the boundary between the convex portion and the concave portion adjacent to the convex portion. The film thickness is not uniform, and H2 is smaller than H1 .

[0078] Figure 5(D) shows another example of embossing on both sides of the film.

[0079] In Figure 5(D), the film 50 is sandwiched between the embossing roll 53 in contact with one side of the film and the embossing roll 55 in contact with the other side of the film, showing the film 50 in the process of being sent out in the advancing direction 60.

[0080] Figure 5(D) is a combination of the embossing roll 53 with male pattern and the embossing roll 55 with female pattern. Also, due to the continuous convex and concave patterns where part of the surface of the film 50 is raised and the surface is depressed, a pattern is formed on the surface of the film 50 .

[0081] Figure 5(E) uses the embossing roll 56 with a changed pitch of the protrusions formed on one of the embossing rolls 55 in Figure 5(D). Here, the pitch of the protrusions or the pitch of the embossing refers to the distance between the vertices of adjacent protrusions. For example, the distance P in Figure 5(E) is referred to as the pitch of the protrusions or the pitch of the embossing. Figure 5(E) shows the film 50 sandwiched between the embossing roll 53 and the embossing roll 56 and in the process of being sent out in the advancing direction 60 . . By changing the pitch of the protrusions, embossing with different embossing pitches can be performed on both sides of the film. This can be done.

[0082] In Fig. 5(F), the film 50 is sandwiched between an embossing roll 57 in contact with one surface of the film and an embossing roll 58 in contact with the other surface, showing the film 50 in the middle of being fed out in the film's advancing direction 60.

[0083] Fig. 5(F) is also called Tip to Tip double-sided embossing, and is a combination of an embossing roll 5 7 and an embossing roll 58 with the same pattern as the embossing roll 57. The phases of the convex and concave parts of the same embossing roll are aligned, and a pattern with almost no difference between the front and back of the film 50 can be formed. Also, different from Fig. 5(F), it is also possible to perform embossing without aligning the phases of the convex and concave parts of the same embossing roll.

[0084] Also, it is not limited to using an embossing roll, and an embossing plate may be used. Moreover, it is not limited to embossing, and a relief may be formed on a part of the film.

[0085] An example of a power storage device 500 using an exterior body 529 with unevenness formed by the above embossing is shown in Fig. 6(A). Also, Fig. 6(B) shows a sectional view between the dashed-dotted line H1 - H2 in Fig. 6(A). The configuration excluding the exterior body 529 in Fig. 6(B) is the same as that in Fig. 3(B).

[0086] The unevenness of the exterior body 529 is formed so as to include the regions overlapping with the positive electrode 503 and the negative electrode 506. In Fig. 6(A), there is no unevenness formed at the joint 518, but a concave is formed at the joint 518. ​​​​​​​A convex portion may be formed.

[0087] In addition, the unevenness of the exterior body 529 is periodically formed in the longitudinal axis direction of the power storage device 500 (the Y direction shown in FIG. 6(A) ). In other words, one concave portion and one convex portion are formed so as to extend in the short axis direction of the power storage device 500 (the X direction shown in FIG. 6(A)). By having such unevenness , when the power storage device 500 is bent in the longitudinal axis direction, the stress applied can be relaxed.

[0088] Note that the unevenness of the exterior body 529 may be formed so that a geometric pattern in which two diagonal lines intersect can be visually recognized (see FIG. 7). By having such unevenness, the stress generated in at least two-directional bending of the power storage device 500 can be relaxed.

[0089] In FIG. 1(A), the positive electrode lead 510 and the negative electrode lead 511 are arranged on the same side of the power storage device 500. However, as shown in FIG. 8, the positive electrode lead 510 and the negative electrode lead 511 may be arranged on different sides of the power storage device 500. Thus, in the power storage device according to one aspect of the present invention, the leads can be freely arranged, so the degree of design freedom is high. Therefore, the degree of design freedom of a product using the power storage device according to one aspect of the present invention can be increased. In addition, the productivity of a product using the power storage device according to one aspect of the present invention can be increased.

[0090] <Example of manufacturing method of power storage device> Next, an example of a manufacturing method of the power storage device 500, which is a power storage device according to one aspect of the present invention, will be described with reference to FIGS. 9 to 11.

[0091] First, the positive electrode 503, the negative electrode 506, and the separator 507 are laminated. Specifically, the positive electrode 5 Place separator 507 on top of 03. Then, place negative electrode 506 on top of separator 507. When using two or more sets of positive and negative electrodes, further place separator 507 on top of negative electrode 506, and then place positive electrode 503. In this way, alternately stack positive electrode 503 and negative electrode 506 while sandwiching separator 507 between positive electrode 503 and negative electrode 506. Or, separator 507 may be made into a bag shape. Wrapping the electrode with separator 507

[0092] makes the electrode less likely to be damaged during the manufacturing process, which is preferable.

[0093] First, place positive electrode 503 on separator 507. Next, fold separator 507 at the portion indicated by the dashed line in Fig. 9( A) and sandwich positive electrode 503 with separator 507. Here, an example of sandwiching positive electrode 503 with separator 507 has been described, but negative electrode 506 may also be sandwiched with separator 5 07.

[0094] Here, it is preferable to join the outer peripheral portion of separator 507 outside positive electrode 503 to make separator 507 into a bag shape (or envelope shape). The joining of the outer peripheral portion of separator 507 may be performed using an adhesive or the like, or by ultrasonic welding or heat fusion.

[0095] Next, join the outer peripheral portion of separator 507 by heating. The joining portion 514 is shown in Fig. 9(A). In this way, positive electrode 503 can be covered with separator 507.

[0096] When using materials such as cellulose or paper as separator 507, the outer peripheral portion of separator 507 is joined using an adhesive or the like, but the amount of the adhesive is preferably small. Separe The electrode (positive electrode 503 in FIG. 9(A)) sandwiched between the separator 507 The outer periphery needs to be joined so that it does not protrude. For example, as shown in FIG. 9(B), By forming 514, the amount of adhesive can be reduced. The crease-line-forming portion is located on the outer periphery of the fold 507, and the crease-line-forming portion is located on the outer periphery of the fold 507. A joint portion 514 is formed on a part of the side opposite to the side on which the joint portion is formed.

[0097] Next, as shown in FIG. 9(C), the negative electrode 506 and the positive electrode 503 covered with the separator are The positive electrode lead 510 and the negative electrode lead 511 having the sealing layer 115 are stacked alternately. Prepare.

[0098] Next, as shown in FIG. 10(A), a sealing layer 115 is formed on the tab region 281 of the positive electrode 503. A positive electrode lead 510 is connected to the joint 512. An enlarged view of the connection is shown in FIG. Ultrasonic waves are applied while applying pressure to the tab region 281 of the positive electrode 503 and the positive electrode lead 510. At this time, a curved portion 513 is provided in the tab region 281. It is good.

[0099] By providing the curved portion 513, it is possible to prevent the electric storage device 500 from being subjected to an external force after the device is manufactured. This can reduce the stress that occurs when the battery is turned on, thereby improving the reliability of the power storage device 500. do.

[0100] Using a similar method, the tab area 282 of the negative electrode 506 and the negative electrode lead 511 are electrically connected. It can be connected.

[0101] Next, the positive electrode 503 , the negative electrode 506 , and the separator 507 are placed on the exterior body 509 .

[0102] Next, bend the exterior body 509 at the portion indicated by the dashed line near the center of the exterior body 509 in Fig. 10(C). Bend it.

[0103] Fig. 11 shows the portion where the outer periphery of the exterior body 509 is joined by thermocompression bonding as the joint portion 118. The outer peripheral portion of the exterior body 509 other than the inlet 119 for injecting the electrolytic solution 508 is joined by thermocompression bonding. During thermocompression bonding, the sealing layer provided on the lead also melts to fix the space between the lead and the exterior body 509. In addition, the adhesion between the exterior body 509 and the lead can be improved.

[0104] Then, a desired amount of the electrolytic solution 508 is introduced into the interior of the exterior body 509 from the inlet 119 under a reduced pressure atmosphere or an inert gas atmosphere. Finally, the inlet 119 is joined by thermocompression bonding. In this way, the power storage device 500, which is a thin power storage device, can be manufactured.

[0105] After manufacturing the power storage device 500, aging may be performed. An example of the aging conditions will be described below. First, charge at a rate of 0.001C or more and 0.2C or less. The temperature may be, for example, room temperature or higher and 50°C or lower. At this time, if the electrolytic solution decomposes and gas is generated, when the gas accumulates between the electrodes, a region where the electrolytic solution cannot contact the electrode surface will be generated. That is, it corresponds to a decrease in the effective reaction area of the electrode and an increase in the effective resistance.

[0106] When the resistance becomes excessively high, the negative electrode potential drops, causing lithium to be inserted into the graphite and at the same time lithium to precipitate on the graphite surface. This precipitation of lithium results in a decrease in capacity. ​​​This may lead to, for example, after lithium is deposited, if a film or the like grows on the surface, the lithium deposited on the surface cannot be redissolved, resulting in lithium that does not contribute to the capacity. Also, when the deposited lithium physically collapses and loses electrical connection with the electrode, again lithium that does not contribute to the capacity is generated. Therefore, it is preferable to vent the gas so that the negative electrode potential does not reach the lithium potential due to the increase in the charging voltage.

[0107] When venting the gas, for example, a part of the exterior of the thin-type power storage device may be cut and opened. When the exterior is swollen due to gas, it is preferable to reshape the exterior again. Also, the electrolytic solution may be added as necessary before resealing. When gas venting cannot be performed, a space for gas evacuation may be provided inside the cell to evacuate the gas accumulated between the electrodes from between the electrodes. The space generated by using the embossed laminate exterior described above can also be used as a space for gas evacuation.

[0108] Also, after venting the gas, at a temperature higher than room temperature, preferably 30°C or higher and 60°C or lower, more preferably 35°C or higher and 50°C or lower, for example, for a period of 1 hour or more and 100 hours or less, it may be held in a charged state. When charging for the first time, the electrolytic solution decomposed on the surface forms a film. Therefore, for example, by holding at a temperature higher than room temperature after gas venting, it is conceivable that the formed film becomes denser.

[0109] <Components of the power storage device> Hereinafter, the components of the power storage device according to one aspect of the present invention will be described in detail. Note that, when a flexible material is selected and used from the materials of each member shown in this embodiment, a flexible one is obtained. A power storage device can be manufactured.

[0110] ≪Separator≫ In the power storage device of one embodiment of the present invention, a separator containing polyphenylene sulfide or solvent-spun regenerated cellulose fibers is used. The separator may have a single-layer structure or a laminated structure. For example, it may have a laminated structure of a separator containing solvent-spun regenerated cellulose fibers and another separator.

[0111] As materials that can be used for the separator, in addition to polyphenylene sulfide and solvent-spun regenerated cellulose fibers, polypropylene sulfide, fluorine-based polymers, cellulose, paper, non-woven fabric, glass fiber, ceramics, or one or more selected from synthetic fibers such as nylon (polyamide), vinylon (polyvinyl alcohol-based fiber), polyester, acrylic, polyolefin, polyurethane can be used.

[0112] ≪Electrolyte solution≫ The electrolyte solution contains an electrolyte and a solvent. In this specification and the like, the electrolyte may be referred to as a solute.

[0113] As the solvent of the electrolyte solution, a material in which carrier ions can move is used. In particular, a solvent having high heat resistance and low reactivity with the graphite negative electrode is preferable. In the power storage device of one embodiment of the present invention, a mixture of PC and EC is used as the solvent.

[0114] Also, an aprotic organic solvent is preferable as the solvent. In addition to EC and PC, butylene car bonate, γ-butyrolactone, γ-valerolactone, dimethyl sulfoxide, methyl One of diglyme, benzonitrile, sulfolane, or two or more thereof can be used in any combination and ratio.

[0115] Also, by using a polymer material that gels as a solvent for the electrolytic solution, safety against leakage and the like is enhanced. Also, the power storage device can be made thinner and lighter. Representative examples of the gelling polymer material include silicone gel, acrylic gel, acrylonitrile gel, polyethylene oxide-based gel, polypropylene oxide-based gel, fluorine-based polymer gel, and the like. Representative examples of the gelling polymer material include silicone gel, acrylic gel, acrylonitrile gel, polyethylene oxide-based gel, polypropylene oxide-based gel, fluorine-based polymer gel, and the like. oxide-based gel, polypropylene oxide-based gel, fluorine-based polymer gel, and the like. There are.

[0116] Also, by using one or more ionic liquids (also called room temperature molten salts) that are flame retardant and have low volatility as a solvent for the electrolytic solution, even if the internal temperature of the power storage device rises due to internal short circuit, overcharging, etc., rupture, ignition, etc. of the power storage device can be prevented. Thereby, the safety of the power storage device can be enhanced. ) can be used to prevent rupture, ignition, etc. of the power storage device even if the internal temperature of the power storage device rises due to internal short circuit, overcharging, etc. Thereby, the safety of the power storage device can be enhanced. rising, rupture, ignition, etc. of the power storage device can be prevented. Thereby, the safety of the power storage device can be enhanced. safety can be improved.

[0117] As the solute, a material that can move carrier ions and has carrier ions can be used. When the carrier ion is a lithium ion, the solute is a lithium salt. Preferred lithium salts to be used include highly heat-resistant LiBETA, lithium bis(trifluoromethanesulfonyl)amide (Li(CF3SO2)2N, abbreviation: LiTFSA), lithium bis(fluorosulfonyl)amide (Li(FSO2)2N, abbreviation: LiFSA), LiBF4, lithium bis(oxalato)borate (LiB(C2O4)2, abbreviation: LiBOB), etc. As the solute, a material that can move carrier ions and has carrier ions can be used. When the carrier ion is a lithium ion, the solute is a lithium salt. salt. Preferred lithium salts to be used include highly heat-resistant LiBETA, lithium bis(trifluoromethanesulfonyl)amide (Li(CF3SO2)2N, abbreviation: LiTFSA), lithium bis(trifluoromethanesulfonyl)amide (Li(CF3SO2)2N, abbreviation: LiTFSA) lithium bis(fluorosulfonyl)amide (Li(FSO2)2N, abbreviation: LiFSA) lithium bis(fluorosulfonyl)amide (Li(FSO2)2N, abbreviation: LiFSA) OB), etc. are preferred.

[0118] By the way, in the battery reaction in the power storage device, the electrolytic solution reacts with the current collector of the positive electrode and contains When the elution of the contained metal occurs, it causes a decrease in the capacity of the power storage device and the power storage device deteriorates. That is, when a cycle characteristic test of the power storage device is performed, the capacity decreases significantly every time charge and discharge are repeated, resulting in a power storage device with a short lifespan. In addition, when the elution of the current collector at the connection part with the lead progresses, disconnection may occur. Therefore, in one aspect of the present invention, the solute material contained in the electrolytic solution uses a material in which the reaction with the current collector is suppressed and the elution of the metal in the current collector is suppressed.

[0119] Examples of the metal in the current collector material of the positive electrode include aluminum or stainless steel. In one aspect of the present invention, the material of the solute used in the electrolytic solution uses a solute in which the elution from these metal positive current collectors is suppressed. Specifically, a solute that can be used in one aspect of the present invention includes LiBETA as a lithium salt.

[0120] In the power storage device according to one aspect of the present invention, since the elution of the metal in the positive current collector into the electrolytic solution is suppressed, the deterioration of the positive current collector is suppressed, and the precipitation of the metal on the negative electrode surface is also suppressed, so that it is possible to obtain a power storage device with a small capacity deterioration and a good cycle life.

[0121] In addition to the above electrolytes, for example, one or more lithium salts such as LiPF6, LiClO4, LiAsF6, LiAlCl4, LiSCN, LiBr, LiI, Li2SO4, Li2BCl, Li2BCl, LiCF3SO3, LiC4F9SO3, LiC(CF3SO2)3, 10 Cl 10 Li 2B 12 Cl 12 LiC2F5SO3, LiC(C2F5SO2)3, LiN(C4F9SO2)(CF3SO2), LiN( C2F5SO2)2, etc. can be used in any combination and ratio. ​

[0122] Incidentally, among the above electrolytes, the case where the carrier ion is a lithium ion has been described. However, carrier ions other than lithium ions can also be used. For carrier ions other than lithium ions, in the case of alkali metal ions or alkaline earth metal ions, as the electrolyte, in the above lithium salts, instead of lithium, an alkali metal (for example, sodium lithium, potassium, etc.), an alkaline earth metal (for example, calcium, strontium, barium ium, beryllium, or magnesium, etc.) may be used.

[0123] In addition, additives such as VC, propanesultone (PS), tert-butylbenzene (TBB) fluorethylene carbonate (FEC), and LiBOB may be added to the electrolytic solution. The concentration of the additive may be, for example, 0.1 wt% or more and 5 wt% or less with respect to the entire solvent.

[0124] When the above solvent and the above electrolyte are used, an electrolytic solution of a power storage device according to one embodiment of the present invention can be produced.

[0125] <<Current collector>> The current collector has no particular limitation as long as it exhibits high conductivity without causing a significant chemical change in the power storage device. For the positive electrode current collector and the negative electrode current collector, for example, metals such as stainless steel, gold, platinum, zinc, iron , nickel, copper, aluminum, titanium, tantalum, manganese, alloys thereof, or sintered carbon can be used respectively. Alternatively, copper or stainless steel may be coated with carbon, nickel, titanium, etc. and used. Alternatively, silicon, titanium elements such as neodymium, scandium, and molybdenum that improve heat resistance are added to aluminum ​ A minium alloy can be used. Or, it reacts with silicon to form a silicide. A current collector may be formed of a metal element. A metal element that reacts with silicon to form a silicide includes zirconium, titanium, hafnium, vanadium, niobium, tantalum, chromium molybdenum, tungsten, cobalt, nickel, and the like.

[0126] On the surface of the positive electrode current collector or the surface of the negative electrode current collector, an irreversible reaction with the electrolytic solution may occur. Therefore, it is preferable that the positive electrode current collector and the negative electrode current collector have low reactivity with the electrolytic solution.

[0127] In addition, the positive electrode current collector and the negative electrode current collector may each have various shapes including foil shape, plate shape (sheet shape), net shape, cylindrical shape, coil shape, punching metal shape, expanded metal shape, porous shape, and non-woven fabric wrapping. Furthermore, in order to improve the adhesion with the active material layer, the positive electrode current collector and the negative electrode current collector may each have fine irregularities on the surface. In addition, it is preferable to use those having a thickness of 5 μm or more and 30 μm or less for the positive electrode current collector and the negative electrode current collector.

[0128]

[0128] An undercoat layer may be provided on a part of the surface of the current collector. Here, the undercoat layer refers to a coating layer for reducing the contact resistance between the current collector and the active material layer and improving the adhesion between the current collector and the active material layer. Note that the undercoat layer does not have to be formed on the entire surface of one side of the current collector, and may be formed in an island shape (partially). Also, the undercoat layer may function as an active material and exhibit capacitance. As the undercoat layer, for example, a carbon material can be used. As the carbon material, for example, graphite or carbon black such as acetylene black can be used. ​Cu, carbon nanotubes, etc. can be used. Further, as the undercoat layer, a metal layer, a layer containing carbon and a polymer, and a layer containing a metal and a polymer can also be used. .

[0129] ≪Active material layer≫ The active material layer contains an active material. The active material refers only to a substance involved in the insertion and extraction of ions as carriers. In this specification, etc., a layer containing an active material is called an active material layer. The active material layer may contain, in addition to the active material, a conductive assistant and a binder.

[0130] The positive electrode active material layer has one or more positive electrode active materials. The negative electrode active material layer has one or more negative electrode active materials.

[0131] The positive electrode active material and the negative electrode active material play a central role in the battery reaction of the power storage device and are substances that release and absorb carrier ions. In order to increase the life of the power storage device, it is preferable that the active material is a material with a small capacity related to the irreversible reaction of the battery reaction, and it is preferable that the active material is a material with high charge and discharge efficiency.

[0132] For the positive electrode active material, a material capable of inserting and extracting carrier ions such as lithium ions can be used. Examples of the positive electrode active material include materials having an olivine-type crystal structure, a layered rock salt-type crystal structure, a spinel-type crystal structure, a NASICON-type crystal structure, etc.

[0133] For example, as the positive electrode active material, compounds such as LiCoO2, LiNiO2, LiMn2O4, V2O5, Cr2O5, MnO2, LiFeO2, etc. can be used as materials.

[0134] Examples of materials having an olivine-type crystal structure include lithium-containing complex phosphates (general formula LiM PO4 (M is one or more of Fe(II), Mn(II), Co(II), Ni(II))) Examples of representative compounds of the general formula LiMPO4 include LiFePO4, LiNiPO4 , LiCoPO4, LiMnPO4, LiFe a Ni b PO4, LiFe a Co b PO4 , LiFe a Mn b PO4, LiNi a Co b PO4, LiNi a Mn b PO4 (a + b is 1 or less, 0 < a < 1, 0 < b < 1), LiFe c Ni d Co e PO4, LiFe c Ni d Mn e PO4, LiNi c Co d Mn e PO4 (c + d + e is 1 or less, 0 < c < 1, 0 < d < 1, 0 < e < 1), LiFe f Ni g Co h Mn i PO4 (f + g + h + i is 1 or less , 0 < f < 1, 0 < g < 1, 0 < h < 1, 0 < i < 1), etc.

[0135] For example, lithium iron phosphate (LiFePO4) is preferred because it well balances the requirements for a cathode active material, such as safety, stability, high capacity density, high potential , and the presence of lithium ions that can be extracted during initial oxidation (charging).

[0136] Examples of materials having a layered rock salt-type crystal structure include, for example, lithium cobalt oxide (LiCoO 2), LiNiO2, LiMnO2, Li2MnO3, LiNi 0.8 Co 0.2 O2, etc. of the NiCo system (general formula: LiNi x Co 1-x O2 (0 < x < 1)), LiNi 0.5 Mn 0.5 O2, etc. of the NiMn system (general formula: LiNi x Mn 1-x O2 (0 < x < 1)) , LiNi 1 / 3 Mn 1 / 3 Co 1 / 3 O2, etc. of the NiMnCo system (also referred to as NMC. General formula: LiNi x Mn y Co 1-x-y O2 (x > 0, y > 0, x + y < 1)) can be mentioned. Furthermore, Li(Ni 0.8 Co 0.15 Al 0.05 )O2, Li2MnO3 - L iMO2 (M is Co, Ni or Mn), etc. can also be mentioned.

[0137] In particular, LiCoO2 has advantages such as a large capacity, being more stable in the air compared to LiNiO2, and being thermally more stable compared to LiNiO2, so it is preferable.

[0138] Examples of materials having a spinel - type crystal structure include, for example, LiMn2O4, Li 1+x Mn 2-x O4, LiMn 2-x Al x O4 (0 < x < 2), LiMn 1.5 Ni 0.5 O4 etc. can be mentioned.

[0139] To materials having a spinel - type crystal structure containing manganese such as LiMn2O4, a small amount of lithium nickelate (LiNiO2 or LiNi M 1-x M xO2 (where 0 < x < 1, M = Co, Al, etc.) When mixed, it has advantages such as suppressing the elution of manganese and suppressing the decomposition of the electrolytic solution. This is preferable.

[0140] Alternatively, as the positive electrode active material, the general formula is Li (2-j) MSiO4 (M is one or more of Fe(II), Mn(II), Co(II), Ni(II), 0 ≤ j ≤ 2), etc., a lithium-containing composite silicate can be used. Representative examples of the general formula Li MSiO4 include Li (2-j) FeSiO4, Li i (2-j) NiSiO4, Li (2-j) CoSiO4 、Li (2-j) MnSiO4, Li (2-j) Fe (2-j) Ni k SiO4, Li l Fe (2-j) Fe k Co l SiO4, Li (2-j) Fe k Mn l SiO4, Li (2-j) Ni k C o l SiO4, Li (2-j) Ni k Mn l SiO4 (k + l is 1 or less, 0 < k < 1, 0 < l < 1), Li (2-j) Fe m Ni n Co q SiO4, Li (2-j) Fe m Ni n Mn q SiO4, Li (2-j) Ni m Co n Mn q SiO4 (m + n + q is 1 or less, 0 < m < 1, 0 < n < 1, 0 < q < 1), Li (2-j) Fe r Nis Co t Mn u SiO 4 (where r + s + t + u is 1 or less, 0 < r < 1, 0 < s < 1, 0 < t < 1, 0 < u < 1), etc. compounds can be mentioned.

[0141] Or, as the positive electrode active material, A x M2(XO4)3 (A = Li, Na, Mg, M = Fe, Mn, Ti, V, Nb, Al, X = S, P, Mo, W, As, Si) represented by the general formula NASICON type compounds can be used. Examples of NASICON type compounds include Fe 2(MnO4)3, Fe2(SO4)3, Li3Fe2(PO4)3, etc.

[0142] Or, as the positive electrode active material, compounds represented by the general formula Li2MPO4F, Li2MP2O7, Li5MO4 (M = Fe, Mn), perovskite type fluorides such as FeF3, metal chalcogenides (sulfides, selenides, tellurides) such as Ti S2, MoS2, etc., materials having an inverse spinel type crystal structure such as LiMV O4, vanadium oxide systems (V2O5, V6O 13 , LiV3O8, LiVOPO4, etc.), manganese oxides, organic sulfur compounds, etc. can be used.

[0143] Also, as the positive electrode active material, a material obtained by combining a plurality of the above materials may be used. For example, a solid solution obtained by combining a plurality of the above described materials can be used as the positive electrode active material. For example, Li Co 1 / 3 Mn 1 / 3 Ni 1 / 3 O2 and a solid solution of Li2MnO3 can be used as the positive electrode active material can be used.

[0144] In addition, when the carrier ions are alkali metal ions or alkaline earth metal ions other than lithium ions, as the positive electrode active material, in the above lithium compound, lithium-containing composite phosphate, and lithium-containing composite silicate, a compound in which lithium is replaced with a carrier such as an alkali metal (e.g., sodium, potassium, etc.) or an alkaline earth metal (e.g., calcium, strontium, barium, beryllium, magnesium, etc.) may be used. In the case of ions, as the positive electrode active material, in the above lithium compound, lithium-containing composite phosphate, and lithium-containing composite silicate, a compound in which lithium is replaced with a carrier such as an alkali metal (e.g., sodium or potassium, etc.) or an alkaline earth metal (e.g., calcium, strontium, barium, beryllium, magnesium, etc.) may be used.

[0145] The average particle size of the primary particles of the positive electrode active material is preferably, for example, 5 nm or more and 100 μm or less.

[0146] Also, for example, when a lithium-containing composite phosphate having an olivine-type structure is used as the positive electrode active material since the diffusion path of lithium is one-dimensional, lithium diffusion is slow. Therefore, when a lithium-containing composite phosphate having an olivine type structure is used, in order to increase the charge and discharge rate, the average particle size of the positive electrode active material is preferably, for example, 5 nm or more and 1 μm or less. Alternatively, the specific surface area of the positive electrode active material is preferably, for example, 10 m 2 / g or more and 50 m 2 / g or less. .

[0147] In the case of an active material having an olivine structure, compared with, for example, an active material having a layered rock salt-type crystal structure, etc., the structural change accompanying charge and discharge is extremely small, and since the crystal structure is stable, it is stable against operations such as overcharging, etc., and a highly safe power storage device can be realized when used as the positive electrode active material.

[0148] As the negative electrode active material, for example, a carbon-based material, an alloy-based material, etc. can be used.

[0149] Examples of carbon-based materials include graphite, graphitizable carbon (soft carbon), non-graphitizable carbon (hard carbon), carbon nanotubes, graphene, carbon black, etc. Examples of graphite include artificial graphite such as mesocarbon microbeads (MCMB), coke-based artificial graphite, and pitch-based artificial graphite, as well as natural graphite such as spheroidized natural graphite. Also, examples of the shape of graphite include flaky and spherical shapes. When lithium ions are inserted into graphite (when forming a lithium-graphite intercalation compound), it exhibits a potential as low as that of metallic lithium. As a result, lithium-ion secondary batteries can exhibit a high operating voltage. As described above, graphite has advantages such as a relatively high capacity per unit volume, small volume expansion, low cost, and high safety compared to metallic lithium, and thus is preferable. Here, the graphite material will be described. Graphite is a layered compound in which multiple graphene layers are stacked parallel to each other by van der Waals forces. The surface of the graphite material includes a plane parallel to the graphene layer (also referred to as the basal plane or base plane), and a plane formed by arranging the ends of multiple graphene layers (also referred to as the edge plane or end face). On the basal plane, one surface of the outermost graphene layer among the graphene layers constituting the graphite is exposed, and on the edge plane, the ends of multiple graphene layers are exposed. During charge and discharge of the secondary battery, the insertion and extraction of lithium mainly occur through the edge plane of the graphite material. When using graphite as the negative electrode active material, at the locations where the edge plane is exposed, an electrolyte containing PC

[0150]

[0151]

[0152] When it comes into contact, a side reaction between graphite and PC may occur during charge and discharge. The spheroidized natural graphite used as the negative electrode active material of a power storage device according to an aspect of the present invention is in contact with the above edge surface, and since a layer having lower crystallinity than the graphite layer is formed, there is a case where the side reaction between graphite and PC can be suppressed. The spheroidized natural graphite used as the negative electrode active material of the power storage device has a layer with lower crystallinity than the graphite layer in contact with the above edge surface, so that the side reaction between graphite and PC can be suppressed in some cases. When the carrier ion is a lithium ion, as the alloy-based material, for example, a material containing at least one of Mg, Ca, Ga, Si, Al, Ge, Sn, Pb, As, Sb, Bi, Ag, Au, Zn, Cd,

[0153] Hg, In, etc. can be used. Such elements have a larger capacity compared to carbon, and especially silicon has a high theoretical capacity of 4200 mAh / g, so that the capacity of the power storage device can be increased. As the alloy-based material (compound-based material) using such an element, for example, Mg2Si, Mg2Ge, Mg2Sn, SnS2, V2Sn3, FeSn2, CoSn2, Ni3Sn2, Cu6Sn5, Ag3Sn, Ag3Sb, Ni 2MnSb, CeSb3, LaSn3, La3Co2Sn7, CoSb3, InSb, S bSn, etc. are available.

[0154] In addition, as the negative electrode 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 12 ), lithium-graphite intercalation compound (Li x C6), niobium pentoxide (Nb2O5), tungsten oxide (WO2), molybdenum oxide (MoO2 ) can be used. Here, SiO is a compound having silicon and oxygen. When the atomic ratio of silicon to oxygen is silicon:oxygen = α:β, α preferably has a value in the vicinity of β. Here, having a value in the vicinity means that, for example, the absolute value of the difference between α and β is the value of β It is preferably 20% or less, more preferably 10% or less.

[0155] In addition, as the negative electrode active material, a Li3N-type structure, which is a complex nitride of lithium and a transition metal, Li 3-x M x N (where M is Co, Ni, or Cu) can be used. For example, Li 2. 6Co 0.4 N3 exhibits a large charge-discharge capacity (900 mAh / g, 1890 mAh / cm 3 ) and is preferable. Shown and preferable.

[0156] When a complex nitride of lithium and a transition metal is used, since lithium ions are contained in the negative electrode active material, it can be combined with materials such as V2O5 and Cr3O8 that do not contain lithium ions as the positive electrode active material. Even when a material containing lithium ions is used as 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. it can be combined with materials such as V2O5 and Cr3O8 that do not contain lithium ions as the positive electrode active material. Even when a material containing lithium ions is used as the positive electrode active material,

[0157] In addition, a material in which a conversion reaction occurs 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. Materials in which a conversion reaction occurs further include oxides such as Fe2O3, CuO, Cu2O, RuO2, and Cr2O 3, sulfides such as CoS 3, NiS, and CuS, nitrides such as Zn3N2, Cu3N, and G 0.89 e3N4, phosphides such as NiP2, FeP2, and CoP3, and fluorides such as FeF3 and BiF3. e3N4 etc., nitrides, phosphides such as NiP2, FeP2, CoP3 etc., fluorides such as FeF3, BiF3 etc. can be mentioned.

[0158] The average particle size of the primary particles of the negative electrode active material is preferably, for example, 5 nm or more and 100 μm or less.

[0159] The positive electrode active material layer and the negative electrode active material layer may each have a conductive assistant.

[0160] As the conductive assistant, for example, a carbon material, a metal material, a conductive ceramic material, or the like can be used. Moreover, a fibrous material may be used as the conductive assistant. The content of the conductive assistant relative to the total amount of the active material layer is preferably 1 wt% or more and 10 wt% or less, and more preferably 1 wt% or more and 5 wt% or less. % or less.

[0161] With the conductive assistant, an electrical conduction network can be formed in the electrode. With the conductive assistant, the electrical conduction path between the negative electrode active materials can be maintained. By adding the conductive assistant to the active material layer, an active material layer having high electrical conductivity can be realized.

[0162] As the conductive assistant, for example, natural graphite, artificial graphite such as mesocarbon microbeads, carbon fibers, etc. can be used. As the carbon fibers, for example, carbon fibers such as mesophase pitch-based carbon fibers, isotropic pitch-based carbon fibers, etc. can be used. Also, as the carbon fibers, carbon nanofibers, carbon nanotubes, etc. can be used. Carbon nanotubes can be produced, for example, by a vapor phase growth method. Further, as the conductive assistant, for example, carbon materials such as carbon black (such as acetylene black (AB)), graphite (black lead) particles, graphene, graphene oxide, fullerene, etc. can be used. Also, for example, metal powders, metal fibers, conductive ceramic composite materials, etc. such as copper, nickel, aluminum, silver, gold, etc. can be used. ​​​​​​​​​​​

[0163] Flaky graphene has excellent electrical properties such as high conductivity, and excellent physical properties such as flexibility and mechanical strength. Therefore, by using graphene as a conductive aid, the contact points and contact areas between active materials can be increased. Graphene enables surface contact with low contact resistance, and even when thin, it has very high conductivity and can efficiently form conductive paths in the active material layer even in a small amount. When using active materials with a small average particle size, for example, active materials of 1 μm or less, the specific surface area of the active materials is large, and more conductive paths connecting the active materials are required. In such cases, it is particularly preferable to use graphene that has very high conductivity and can efficiently form conductive paths even in a small amount.

[0164] Graphene enables surface contact with low contact resistance, and even when thin, it has very high conductivity and can efficiently form conductive paths in the active material layer even in a small amount. When using active materials with a small average particle size, for example, active materials of 1 μm or less, the specific surface area of the active materials is large, and more conductive paths connecting the active materials are required. In such cases, it is particularly preferable to use graphene that has very high conductivity and can efficiently form conductive paths even in a small amount.

[0165] The positive electrode active material layer and the negative electrode active material layer may each have a binder. In this specification, the binder has a function of binding or adhering active materials to each other and / or a function of binding or adhering the active material layer to the current collector. Also, the state of the binder may change during the production of the electrode or the battery. For example, the binder may take at least one state such as a liquid, a solid, or a gel. Also, the binder may change from a monomer to a polymer during the production of the electrode or the battery. For example, a water-soluble polymer can be used as the binder. As the water-soluble polymer, for example, polysaccharides can be used. As the polysaccharide, carboxymethyl cellulose When using active materials with a small average particle size, for example, active materials of 1 μm or less, the specific surface area of the active materials is large, and more conductive paths connecting the active materials are required. In such cases, it is particularly preferable to use graphene that has very high conductivity and can efficiently form conductive paths even in a small amount.

[0166] The positive electrode active material layer and the negative electrode active material layer may each have a binder.

[0167] In this specification, the binder has a function of binding or adhering active materials to each other and / or a function of binding or adhering the active material layer to the current collector. Also, the state of the binder may change during the production of the electrode or the battery. For example, the binder may take at least one state such as a liquid, a solid, or a gel. Also, the binder may change from a monomer to a polymer during the production of the electrode or the battery. For example, a water-soluble polymer can be used as the binder. As the water-soluble polymer, for example, polysaccharides can be used. As the polysaccharide, carboxymethyl cellulose For example, a water-soluble polymer can be used as the binder. As the water-soluble polymer, for example, polysaccharides can be used. As the polysaccharide, carboxymethyl cellulose For example, a water-soluble polymer can be used as the binder. As the water-soluble polymer, for example, polysaccharides can be used. As the polysaccharide, carboxymethyl cellulose For example, a water-soluble polymer can be used as the binder. As the water-soluble polymer, for example, polysaccharides can be used. As the polysaccharide, carboxymethyl cellulose

[0168] For example, a water-soluble polymer can be used as the binder. As the water-soluble polymer, for example, polysaccharides can be used. As the polysaccharide, carboxymethyl cellulose For example, a water-soluble polymer can be used as the binder. As the water-soluble polymer, for example, polysaccharides can be used. As the polysaccharide, carboxymethyl cellulose (CMC), methyl cellulose, ethyl cellulose, hydroxypropyl cellulose, di cellulose derivatives such as acetyl cellulose and regenerated cellulose, and starches can be used. It is possible.

[0169] Also, as a binder, rubber materials such as styrene-butadiene rubber (SBR), styrene-isoprene-styrene rubber, acrylonitrile-butadiene rubber, butadiene rubber, fluororubber, and ethylene-propylene-diene copolymer can be used. These rubber materials can be used in combination with the aforementioned water-soluble polymers. These rubber materials have rubber elasticity and are easy to stretch and contract, so they are resistant to the expansion and contraction of the active material accompanying charge and discharge and the stress accompanying bending of the electrode, etc., and a highly reliable electrode can be obtained. On the other hand, they have a hydrophobic group and may not dissolve in water. In such a case, since the particles are dispersed in a state where they do not dissolve in water in an aqueous solution, it may be difficult to increase the viscosity of the composition containing the solvent used for forming the active material layer (also referred to as the electrode binder composition) to a viscosity suitable for coating. At this time, when a water-soluble polymer with a high viscosity adjustment function, such as a polysaccharide, is used, the effect of moderately increasing the viscosity of the solution can be expected. In addition, it can be uniformly dispersed with the rubber material, and a good electrode with high uniformity, such as an electrode with high uniformity in electrode film thickness and electrode resistance, can be obtained. Or, as a binder, PVdF, polystyrene, polymethyl acrylate, polymethyl methacrylate (PMMA), sodium polyacrylate, polyvinyl alcohol (PVA), polyethylene oxide (PEO), polypropylene oxide (PEO), etc. can be used. These binders can be used alone or in combination with other binders. When these binders are used alone, they have good film-forming properties and can form a uniform and dense binder layer on the surface of the active material, which helps to improve the adhesion between the active material and the current collector and the mechanical strength of the electrode. When used in combination with other binders, they can play a complementary role, for example, improving the conductivity, hydrophilicity, or chemical stability of the electrode. In addition, some binders have functional groups that can interact with the active material or the electrolyte, which helps to improve the electrochemical performance of the battery. For example, they can enhance the charge transfer efficiency at the electrode / electrolyte interface, reduce the internal resistance of the battery, and improve the cycle life and rate performance of the battery.

[0170] Or, as a binder, PVdF, polystyrene, polymethyl acrylate, polymethyl methacrylate (PMMA), sodium polyacrylate, polyvinyl alcohol (PVA), polyethylene oxide (PEO), polypropylene oxide (PEO), etc. can be used. These binders can be used alone or in combination with other binders. When these binders are used alone, they have good film-forming properties and can form a uniform and dense binder layer on the surface of the active material, which helps to improve the adhesion between the active material and the current collector and the mechanical strength of the electrode. Cide, polyimide, polyvinyl chloride, polytetrafluoroethylene, polyethylene, poly propylene, polyisobutylene, polyethylene terephthalate, nylon, polyacrylo nitrile (PAN), ethylene propylene diene polymer, polyvinyl acetate, nitrocell lose and other materials can be used.

[0171] Two or more of the above binders may be used in combination.

[0172] The content of the binder relative to the total amount of the active material layer is preferably 1 wt% or more and 10 wt% or less, more preferably 2 wt% or more and 8 wt% or less, and even more preferably 3 wt% or more and 5 wt% or less.

[0173] ≪Outer package≫ The inner surface of the outer package 509 that contacts the electrolytic solution 508, i.e., the inner surface, preferably does not cause a significant reaction with the electrolytic solution 508. Also, when moisture enters the power storage device 500 from the outside of the power storage device 500, a reaction may occur between the components of the electrolytic solution 508 and water. Therefore, the outer package 5 09 preferably has low water permeability.

[0174] For the outer package 509, for example, on a film made of polyethylene, polypropylene, polycarbonate, ionomer, polyamide, etc., a metal thin film with excellent flexibility such as aluminum, stainless steel, copper, nickel, etc. is provided, and further, an insulating synthetic resin film such as a polyamide-based resin or a polyester-based resin is provided as the outer surface of the outer package, and a three-layer structure film can be used. By adopting such a three-layer structure, the permeation of the electrolytic solution and gas is blocked, insulation is ensured, and at the same time, it has resistance to the electrolytic solution. The outer package is bent and overlapped inside, or 2 ​​​​​​By facing and overlapping the inner surfaces of each of the outer bodies and applying heat, the material on the inner surface melts and the two outer bodies can be fused to create a sealing structure.

[0175] If the portion where the outer bodies are fused or the like to form a sealing structure is defined as the sealing portion, when the outer bodies are folded inward and overlapped, the sealing portion is formed at a location other than the fold, and a structure is formed in which the first region of the outer body and a second region overlapping the first region are fused or the like. Also, when two outer bodies are overlapped a sealing portion is formed on the entire outer periphery by a method such as heat fusion.

[0176] The power storage device 500 can have a flexible configuration by using a flexible outer body 509. If it has a flexible configuration, it can be mounted on an electronic device having at least a part of a flexible portion, and the power storage device 500 can also be bent in accordance with the deformation of the electronic device.

[0177] In addition, in one aspect of the present invention, a graphene compound can be used for each member constituting the power storage device. As will be described later, since the structure and properties of the graphene compound can be widely selected by modification, preferred properties can be exhibited according to the member to which the graphene compound is to be applied. Also, since the graphene compound has high mechanical strength, the graphene compound can also be applied to each member constituting a flexible power storage device. Hereinafter, the graphene compound will be described.

[0178] Graphene is a material in which carbon atoms are arranged in a single atomic layer and have π bonds between carbon atoms. The case where two or more and 100 or less layers of graphene are overlapped may be referred to as multi - graphene. Graphene and multi - layer graphene have, for example, a length in the longitudinal direction or the major axis in the plane of 50 nm or more and 100 μm or less, or 800 nm or more and 50 μm or less.

[0179] In this specification and the like, a compound having graphene or multi - layer graphene as a basic skeleton is referred to as a "graphene compound (also referred to as "Graphene Compound")." The graphene compound includes graphene and multi - layer graphene. .

[0180] Details of the graphene compound will be described below.

[0181] The graphene compound is, for example, a compound in which graphene or multi - layer graphene is modified with an atom other than carbon, or an atomic group having an atom other than carbon. Also, it may be a compound in which graphene or multi - layer graphene is modified with a carbon - based atomic group such as an alkyl group or an alkylene group. Here, the atomic group that modifies graphene or multi - layer graphene may be referred to as a substituent group, a functional group, or a characteristic group, etc. Here, in this specification and the like, modification means introducing an atom other than carbon, an atomic group having an atom other than carbon, or a carbon - based atomic group into graphene, multi - layer graphene, a graphene compound, or graphene oxide (described later) by a substitution reaction, an addition reaction, or other reactions. Note that the front and back surfaces of graphene may be modified with different atoms or atomic groups. Also, in multi - layer graphene, each layer may be modified with different atoms or atomic groups.

[0182] In addition, the front and back surfaces of graphene may be modified with different atoms or atomic groups, respectively. Also, in multi - layer graphene, each layer may be modified with different atoms or atomic groups. .

[0183] As an example of graphene modified by the above atoms or atomic groups, graphene or multi-layer graphene modified with oxygen or a functional group containing oxygen can be mentioned. Here, examples of the functional group containing oxygen include carbonyl groups such as epoxy groups and carboxyl groups, or hydroxyl groups. A graphene compound modified with oxygen or a functional group having oxygen may be called graphene oxide. In the present specification, graphene oxide shall also include multi-layer graphene oxide. As an example of the modification in graphene oxide, the silylation of graphene oxide will be described. First, in a nitrogen atmosphere, graphene oxide is placed in a container, n-butylamine (C4H9NH2) is added to the container, and the temperature is maintained at 60 °C and stirred for 1 hour. Next, toluene is added to the container, and as a silylating agent, alkyltrichlorosilane is further added, and in a nitrogen atmosphere, the temperature is maintained at 60 °C and stirred for 5 hours. Next, more toluene is added to the container, and suction filtration is performed to obtain a solid powder, which is dispersed in ethanol. Further, suction filtration is performed to obtain a solid powder, which is dispersed in acetone. Further, suction filtration is performed to obtain a solid powder, and the liquid component is vaporized to obtain silylated graphene oxide. Note that the modification is not limited to silylation, and silylation is also not limited to the above method. Also, not only one type of atom or atomic group is introduced, but multiple types of modifications may be performed and multiple types of atoms or atomic groups may be introduced. By introducing a specific atomic group into the graphene compound, the physical properties of the graphene compound can be changed. Therefore, the use of the graphene compound can be expanded. The modification is not limited to silylation, nor is silylation limited to the above method. Also, not only one type of atom or atomic group is introduced, but multiple types of modifications may be performed and multiple types of atoms or atomic groups may be introduced. By introducing a specific atomic group into the graphene compound, the physical properties of the graphene compound can be changed. Therefore, the applications of the graphene compound can be expanded.

[0184] As an example of the modification in graphene oxide, the silylation of graphene oxide will be described. First, in a nitrogen atmosphere, graphene oxide is placed in a container, n-butylamine (C4H9NH2) is added to the container, and the temperature is maintained at 60 °C and stirred for 1 hour. Next, toluene is added to the container, and as a silylating agent, alkyltrichlorosilane is further added, and in a nitrogen atmosphere, the temperature is maintained at 60 °C and stirred for 5 hours. Next, toluene is added to the container, and as a silylating agent, alkyltrichlorosilane is further added, and in a nitrogen atmosphere, the temperature is maintained at 60 °C and stirred for 5 hours. Next, toluene is added to the container, and as a silylating agent, alkyltrichlorosilane is further added, and in a nitrogen atmosphere, the temperature is maintained at 60 °C and stirred for 5 hours. Next, more toluene is added to the container, and suction filtration is performed to obtain a solid powder, which is dispersed in ethanol. Further, suction filtration is performed to obtain a solid powder, which is dispersed in acetone. Further, suction filtration is performed to obtain a solid powder, and the liquid component is vaporized to obtain silylated graphene oxide.

[0185] Note that the modification is not limited to silylation, nor is silylation limited to the above method. Also, not only one type of atom or atomic group is introduced, but multiple types of modifications may be performed and multiple types of atoms or atomic groups may be introduced. By introducing a specific atomic group into the graphene compound, the physical properties of the graphene compound can be changed. Therefore, the applications of the graphene compound can be expanded. By performing desirable modifications according to the situation, desired properties can be intentionally expressed in the graphene compound. It can be made to happen.

[0186] Next, an example of a method for producing graphene oxide will be described. Graphene oxide can be obtained by oxidizing the above-mentioned graphene or multi-graphene. Alternatively, graphene oxide can be obtained by separating oxidized graphite. Oxidized graphite can be obtained by oxidizing graphite. Here, the above-mentioned atoms or atomic groups may be further used to modify the graphene oxide. It may be.

[0187] A compound obtained by reducing graphene oxide may be referred to as "RGO (Reduced Graphene Oxide)". Note that in RGO, not all of the oxygen contained in graphene oxide is desorbed, and some oxygen or an atomic group containing oxygen may remain bonded to carbon. exist. For example, RGO may have functional groups such as epoxy groups, carbonyl groups such as carboxyl groups, or hydroxyl groups. It may be.

[0188] A graphene compound may be in the form of a single sheet with a plurality of graphene compounds partially overlapping. Such a graphene compound may be referred to as a graphene compound sheet in some cases. There is a case. The graphene compound sheet has, for example, a thickness in the range of 0.33 nm or more and 10 mm or less, more preferably in the range of more than 0.34 nm and 10 μm or less. The graphene compound sheet may be modified by an atom other than carbon, an atomic group having an atom other than carbon, or an atomic group mainly composed of carbon such as an alkyl group. In addition, each of the plurality of layers of the graphene compound sheet may be modified by different atoms or atomic groups. It may be. It may be.

[0189] In addition to the six-membered rings composed of carbon, the graphene compound may also have five-membered rings composed of carbon and polycyclic rings of seven or more members composed of carbon. Here, in the vicinity of the polycyclic rings of seven or more members, a region through which lithium ions can pass may occur.

[0190] Also, for example, a plurality of graphene compounds may aggregate to form a sheet-like shape.

[0191] Since the graphene compound has a planar shape, surface contact is possible.

[0192] The graphene compound may have high conductivity even when thin, and surface contact can increase the contact area between graphene compounds or between a graphene compound and an active material. Therefore, even when the amount per volume is small, an efficient conductive path can be formed.

[0193] On the other hand, the graphene compound can also be used as an insulator. For example, a graphene compound sheet can be used as a sheet-like insulator. Here, for example, graphene oxide may have higher insulating properties compared to a graphene compound that is not oxidized. Also, a graphene compound modified with an atomic group may be able to enhance the insulating property depending on the type of the atomic group to be modified.

[0194] Here, in this specification and the like, the graphene compound may have a graphene precursor. The graphene precursor refers to a substance used for producing graphene, and the graphene precursor may include, for example, the above-mentioned graphene oxide, graphite oxide, and the like.

[0195] Graphene having an alkali metal or graphene having an element other than carbon such as oxygen may be referred to as a graphene analog. In this specification and the like, graphene compounds include graphene analogs.

[0196] In addition, the graphene compounds in this specification and the like may have atoms, atomic groups, and ions thereof between the layers. Note that when the graphene compound has atoms, atomic groups, and ions thereof between the layers, the physical properties of the graphene compound, such as electrical conductivity and ionic conductivity may change. Also, the interlayer distance may increase.

[0197] Graphene compounds may have excellent electrical properties such as high conductivity and excellent physical properties such as high flexibility and high mechanical strength. Also, depending on the type of modification, the graphene compound may be able to reduce the conductivity extremely low to become an insulator. Further, the graphene compound has a planar shape. The graphene compound enables low surface contact with low contact resistance.

[0198] This embodiment can be appropriately combined with other embodiments.

[0199] (Embodiment 2) In this embodiment, an electronic device according to an aspect of the present invention will be described with reference to FIGS. 12 to 15.

[0200] <Configuration Example 1 of Smartwatch> FIG. 12(A) shows a perspective view of a wristwatch-type portable information terminal (also referred to as a smartwatch) 700. The portable information terminal 700 includes a housing 701, a display panel 702, a buckle 703, bands 705A and 705B, and operation buttons 711 and 712.

[0201] The display panel 702 mounted on the housing 701 that also serves as a bezel portion has a rectangular display area and is curved. The display panel 702 preferably has flexibility. Note that the display area may be non-rectangular.

[0202] The bands 705A and 705B are connected to the housing 701. The fastener 703 is connected to the band 705A. The band 705A and the housing 701 are connected, for example, such that a pin can be used as an axis at the connection portion and they can move. The connection between the band 705B and the housing 701, as well as the connection between the band 705A and the fastener 703, is the same.

[0203] Perspective views of the band 705A and the power storage device 750 are shown in FIGS. 12(B) and 12(C), respectively. The band 705A has the power storage device 750. For the power storage device 750, for example, the power storage device 500 described in Embodiment 1 can be used. The power storage device 750 is embedded inside the band 705A, and a part of each of the positive electrode lead 751 and the negative electrode lead 752 protrudes from the band 705A (see FIG. 12(B)). The positive electrode lead 751 and the negative electrode lead 752 are electrically connected to the display panel 702. Also, the surface of the power storage device 750 is covered with an exterior body 753 (see FIG. 12(C)). Note that the above pins may have the function of electrodes. Specifically, the positive electrode lead 751 and the display panel 702, as well as the negative electrode lead 752 and the display panel 702, may be electrically connected via the pins that connect the band 705A and the housing 701, respectively. By doing so, the configuration at the connection portion of the band 705A and the housing 701 can be simplified. ​​​​​​​​​​​​​​

[0204] The power storage device 750 has flexibility. It is preferable that the surface has projections and recesses formed by the embossing process described above. It is preferable that 750 has a sliding surface similar to that of the power storage device 500 shown in FIG.

[0205] The band 705A can be manufactured by being integrally formed with the power storage device 750. For example, The electric storage device 750 is set in a mold corresponding to the outer shape of the band 705A, and the material of the band 705A is poured into the mold. The material is poured into a mold and cured to produce the band 705A shown in FIG. 12(B). do.

[0206] When a rubber material is used as the material of the band 705A, the rubber is hardened by heat treatment. For example, if fluororubber is used as the rubber material, heat treatment at 170℃ for 10 minutes will If silicone rubber is used as the rubber material, heat it at 150℃ for 10 minutes. The power storage device of one embodiment of the present invention has high heat resistance, and therefore the heat treatment is performed to harden the power storage device. This can suppress damage during heat treatment associated with integral formation of the battery and deterioration of charge / discharge characteristics.

[0207] The materials used for the band 705A include fluororubber, silicone rubber, and fluorosilicone. Examples include corn rubber and urethane rubber.

[0208] In addition, the power supply to the power storage device 750, including the aging, is performed by forming the band 705A integrally with the power storage device 750. In other words, the power storage device 500 described in the first embodiment It is preferable to perform a heat treatment before energizing the device 500. The heat treatment is performed at a temperature of 110° C. or higher for 1 At 90°C or less, the vulcanization time is appropriate for the above rubber material, for example, at 170°C. It is preferably performed for 10 minutes. By doing so, deterioration of the charge and discharge characteristics of the power storage device 500 due to the heat treatment can be suppressed.

[0209] Note that the portable information terminal 700 shown in FIG. 12(A) can have various functions. For example, a function of displaying various information (such as still images, moving images, text images, etc.) in the display area, a touch panel function, a function of displaying a calendar, date, or time, etc., a function of controlling processing by various software (programs), a wireless communication function, a function of connecting to various computer networks using the wireless communication function, a function of transmitting or receiving various data using the wireless communication function, a function of reading a program or data recorded on a recording medium and displaying it in the display area, etc.

[0210] Also, inside the housing 701, there can be a speaker, a sensor (including a function of measuring force, displacement, position, speed, acceleration, angular velocity, rotation speed, distance, light, liquid, magnetism, temperature, chemical substance, voice, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, gradient, vibration, odor, or infrared rays), a microphone, etc. Note that the portable information terminal 700 can be manufactured by using a light-emitting element for its display panel 702.

[0211] Note that in FIG. 12, an example in which the power storage device 750 is included in the band 705A is shown, but the power storage device 750 may be included in the band 705B. As the band 705B, the same material as the band 705A can be used.

[0212] The rubber material used for the band 705A preferably has high chemical resistance. Specifically, the power storage It is preferable that the reactivity with respect to the electrolytic solution contained in the device 750 is low.

[0213] Here, even if the band 705A has excellent chemical resistance, cracks or peeling occur in the band 705A In the case of, there is a possibility that the user of the portable information terminal 700 touches the electrolytic solution leaked from the power storage device 750. If the portable information terminal 700 has a function of detecting a leak of the electrolytic solution, when the leak of the electrolytic solution is detected, the user can stop operating and remove the portable information terminal 700. Therefore, a highly safe portable information terminal 700 can be obtained.

[0214] <Configuration Example 2 of Smart Watch> FIG. 13(A) is a perspective view of a band 735A having a configuration different from that of the band 705A shown in FIG. 12(B). The housing 731 connected to the band 735A includes a leak detection circuit (not shown) having a function of detecting a leak of the electrolytic solution of the power storage device (see FIG. 12(A)). Note that the perspective view of the portable information terminal 730 having the leak detection circuit is the same as that of the portable information terminal 700.

[0215] The band 735A has a power storage device 760. The power storage device 760 is embedded inside the band 735A, and the positive electrode lead 751, the negative electrode lead 752, the terminal 761, and the terminal 762 protrude from the band 735A. The positive electrode lead 751 and the negative electrode lead 752 are electrically connected to the display panel 702. The terminals 761 and 762 are electrically connected to, for example, the above-described leak detection circuit.

[0216] FIG. 13(B) shows a perspective view of the power storage device 760. FIG. 13(B) is shown enlarged more than FIG. 13(A) for clarity. The power storage device 760 includes a terminal 761, a terminal 762, and a wiring 77. ​​​​​​​1 and the point having the wiring 772 are different from the power storage device 750 shown in FIG. 12(C). Terminal 7 61 and the wiring 771 are electrically connected. Also, the terminal 762 and the wiring 772 are electrically connected to each other.

[0217] Note that, for the sake of clarity, in FIG. 13(B), the wiring 771 and the wiring 772 are shown with different hatchings but it is preferable to reduce the manufacturing cost by forming the wiring 771 and the wiring 772 from the same material. Also, although the terminal 761 and the wiring 771, and the terminal 762 and the wiring 772 are each shown with the same hatching they may be formed from different materials respectively. The wiring 771 and the wiring 772 are laid on the surface of the exterior body 753 with a predetermined interval therebetween (see FIG. 13(B)). When the electrolytic solution leaks to the surface of the exterior body 753, the leakage detection circuit can detect the leakage of the electrolytic solution by the conduction between the wiring 771 and the wiring 772 through the electrolytic solution.

[0218] FIG. 13(B) shows an arrangement in which the wiring 771 and the wiring 772 are linearly provided in the major axis direction of the power storage device 760, but it is not limited thereto. For example, as shown in FIG. 13(C), the wiring 771 and the wiring 772 may be provided so as to be spaced apart in a comb-like shape and engage with each other.

[0219] Also, FIG. 13(C) shows an example in which the wiring 771 and 772 are provided only on the upper surface of the exterior body 753 but it is preferably provided over the entire surface of the exterior body 753 as shown in FIG. 14(A). FIG. 14(B) is a rear perspective view of the power storage device 760 shown in FIG. 14(A).

[0220]

[0221] ​​​​​​If the film thickness of wirings 771 and 772 is thin and the width is small, it is preferable because the flexibility of the power storage device 760 can be maintained. For example, it is preferable that the power storage device 760 has a region where the film thickness of the wirings 771 and 772 is 5 μm or more and 500 μm or less. Also, since the leakage of the electrolytic solution can be detected even with a small amount because the interval between the wiring 771 and the wiring 772 is small and their widths are small, it is preferable. For example, it is preferable that the power storage device 760 has a region where the interval between the wiring 771 and the wiring 772 is 0.5 mm or more and 20 mm or less. Also, it is preferable that the power storage device 760 has a region where the widths of the wirings 771 and 772 are 0.5 mm or more and 5 mm or less. Further, if the area of the wirings 771 and 772 on the surface of the exterior body 753 is too small, the entire surface of the exterior body 753 cannot be covered against the leakage of the electrolytic solution, and if the area is too large, the flexibility of the power storage device 760 may decrease. In the power storage device 760, it is preferable that the ratio of the surface area of the wirings 771 and 772 excluding the side surfaces (the surfaces in contact with the exterior body 753) to the surface area of the exterior body 753 is 5% or more and 50% or less. For example, it is preferable that the power storage device 760 has a region where the film thickness of the wirings 771 and 772 is 5 μm or more and 500 μm or less. m or more and 500 μm or less. Also, since the leakage of the electrolytic solution can be detected even with a small amount because the interval between the wiring 771 and the wiring 772 is small and their widths are small, it is preferable. For example, it is preferable that the power storage device 760 has a region where the interval between the wiring 771 and the wiring 772 is 0.5 mm or more and 20 mm or less. m or more and 20 mm or less. Also, it is preferable that the power storage device 760 has a region where the widths of the wirings 771 and 772 are 0.5 mm or more and 5 mm or less. m or more and 5 mm or less. Further, if the area of the wirings 771 and 772 on the surface of the exterior body 753 is too small, the entire surface of the exterior body 753 cannot be covered against the leakage of the electrolytic solution, and if the area is too large, the flexibility of the power storage device 760 may decrease. In the power storage device 760, it is preferable that the ratio of the surface area of the wirings 771 and 772 excluding the side surfaces (the surfaces in contact with the exterior body 753) to the surface area of the exterior body 753 is 5% or more and 50% or less. In the power storage device 760, it is preferable that the ratio of the surface area of the wirings 771 and 772 excluding the side surfaces (the surfaces in contact with the exterior body 753) to the surface area of the exterior body 753 is 5% or more and 50% or less. 5% or more and 50% or less.

[0222] As the wirings 771 and 772, it is preferable to include a material with high ductility or malleability. In particular, by using a material with both high ductility and malleability, disconnection of the wirings 771 and 772 due to bending of the power storage device 760 can be suppressed. Examples of materials with high ductility and malleability include metal materials such as gold, silver, platinum, iron, nickel, copper, aluminum, zinc, tin, and alloys containing such metal materials. In particular, by using a material with both high ductility and malleability, disconnection of the wirings 771 and 772 due to bending of the power storage device 760 can be suppressed. Examples of materials with high ductility and malleability include metal materials such as gold, silver, platinum, iron, nickel, copper, aluminum, zinc, tin, and alloys containing such metal materials. nickel, copper, aluminum, zinc, tin, and alloys containing such metal materials. are mentioned.

[0223] ≪Method for Detecting Leakage of Electrolytic Solution≫ An example of a method for detecting the leakage of the electrolytic solution in the portable information terminal 730 will be described below. Do so. Fig. 15(A) shows a block diagram of the configuration of the portable information terminal 730 in a state where the electrolytic solution 736 has leaked. In Fig. 15(A), the line including the arrow indicates the transmission direction of the wired signal or the wireless signal according to the direction of the arrow. Therefore, each element connected by the line may be electrically connected. Also, the line without an arrow indicates wiring, and each element connected by the line is electrically connected. Do so. Fig. 15(A) shows a block diagram of the configuration of the portable information terminal 730 in a state where the electrolytic solution 736 has leaked. In Fig. 15(A), the line including the arrow indicates the transmission direction of the wired signal or the wireless signal according to the direction of the arrow. Therefore, each element connected by the line may be electrically connected. Also, the line without an arrow indicates wiring, and each element connected by the line is electrically connected. Do so. Fig. 15(A) shows a block diagram of the configuration of the portable information terminal 730 in a state where the electrolytic solution 736 has leaked. In Fig. 15(A), the line including the arrow indicates the transmission direction of the wired signal or the wireless signal according to the direction of the arrow. Therefore, each element connected by the line may be electrically connected. Also, the line without an arrow indicates wiring, and each element connected by the line is electrically connected. Do so. Fig. 15(A) shows a block diagram of the configuration of the portable information terminal 730 in a state where the electrolytic solution 736 has leaked. In Fig. 15(A), the line including the arrow indicates the transmission direction of the wired signal or the wireless signal according to the direction of the arrow. Therefore, each element connected by the line may be electrically connected. Also, the line without an arrow indicates wiring, and each element connected by the line is electrically connected. Do so. Fig. 15(A) shows a block diagram of the configuration of the portable information terminal 730 in a state where the electrolytic solution 736 has leaked. In Fig. 15(A), the line including the arrow indicates the transmission direction of the wired signal or the wireless signal according to the direction of the arrow. Therefore, each element connected by the line may be electrically connected. Also, the line without an arrow indicates wiring, and each element connected by the line is electrically connected.

[0224] The portable information terminal 730 includes a leakage detection circuit 732, a power supply 733, an ammeter 734, wiring 771, and wiring 772 (see Fig. 15(A)). The leakage detection circuit 732, the power supply 733, and the ammeter 734 are included in the housing 731. The power supply 733 and the ammeter 734 may be included in the leakage detection circuit 732. Also, the portable information terminal 730 includes a functional circuit 739. The functional circuit 739 includes the above-mentioned speaker, sensor, microphone, etc. The portable information terminal 730 includes a leakage detection circuit 732, a power supply 733, an ammeter 734, wiring 771, and wiring 772 (see Fig. 15(A)). The leakage detection circuit 732, the power supply 733, and the ammeter 734 are included in the housing 731. The power supply 733 and the ammeter 734 may be included in the leakage detection circuit 732. Also, the portable information terminal 730 includes a functional circuit 739. The functional circuit 739 includes the above-mentioned speaker, sensor, microphone, etc. The portable information terminal 730 includes a leakage detection circuit 732, a power supply 733, an ammeter 734, wiring 771, and wiring 772 (see Fig. 15(A)). The leakage detection circuit 732, the power supply 733, and the ammeter 734 are included in the housing 731. The power supply 733 and the ammeter 734 may be included in the leakage detection circuit 732. Also, the portable information terminal 730 includes a functional circuit 739. The functional circuit 739 includes the above-mentioned speaker, sensor, microphone, etc. The portable information terminal 730 includes a leakage detection circuit 732, a power supply 733, an ammeter 734, wiring 771, and wiring 772 (see Fig. 15(A)). The leakage detection circuit 732, the power supply 733, and the ammeter 734 are included in the housing 731. The power supply 733 and the ammeter 734 may be included in the leakage detection circuit 732. Also, the portable information terminal 730 includes a functional circuit 739. The functional circuit 739 includes the above-mentioned speaker, sensor, microphone, etc. The portable information terminal 730 includes a leakage detection circuit 732, a power supply 733, an ammeter 734, wiring 771, and wiring 772 (see Fig. 15(A)). The leakage detection circuit 732, the power supply 733, and the ammeter 734 are included in the housing 731. The power supply 733 and the ammeter 734 may be included in the leakage detection circuit 732. Also, the portable information terminal 730 includes a functional circuit 739. The functional circuit 739 includes the above-mentioned speaker, sensor, microphone, etc. The functional circuit 739 is included in the housing 731.

[0225] The wirings 771 and 772 are electrically connected to the power supply 733, and an arbitrary voltage is applied between the wiring 771 and the wiring 772 (see Fig. 15(A)). The on / off of the power supply 733 is controlled by the leakage detection circuit 732. The wirings 771 and 772 are electrically connected to the power supply 733, and an arbitrary voltage is applied between the wiring 771 and the wiring 772 (see Fig. 15(A)). The on / off of the power supply 733 is controlled by the leakage detection circuit 732. The wirings 771 and 772 are electrically connected to the power supply 733, and an arbitrary voltage is applied between the wiring 771 and the wiring 772 (see Fig. 15(A)). The on / off of the power supply 733 is controlled by the leakage detection circuit 732.

[0226] Fig. 15(B) is a flowchart showing the process of detecting the leakage of the electrolytic solution in the portable information terminal 730. For example, the method of detecting the leakage of the electrolytic solution in the portable information terminal 730 has the following four steps. Fig. 15(B) is a flowchart showing the process of detecting the leakage of the electrolytic solution in the portable information terminal 730. For example, the method of detecting the leakage of the electrolytic solution in the portable information terminal 730 has the following four steps. Fig. 15(B) is a flowchart showing the process of detecting the leakage of the electrolytic solution in the portable information terminal 730. For example, the method of detecting the leakage of the electrolytic solution in the portable information terminal 730 has the following four steps.

[0227] When the electrolytic solution 736 of the power storage device 760 leaks, the electrolytic solution 736 adheres to the surface of the exterior body 753 (see Fig. 15(A), (B) S1). The electrolytic solution 736 adhering to the surface of the exterior body 753 When the electrolytic solution 736 of the power storage device 760 leaks, the electrolytic solution 736 adheres to the surface of the exterior body 753 (see Fig. 15(A), (B) S1). The electrolytic solution 736 adhering to the surface of the exterior body 753 By coming into contact with wirings 771 and 772, current flows through wirings 771 and 772 (see S2 in Fig. 15(B)). When an ammeter 734 connected in parallel to wiring 772 detects this current, the ammeter 734 outputs a detection signal to a liquid leakage detection circuit 732 (see S3 in Fig. 15(B)). According to the detection signal, the liquid leakage detection circuit 732 stops the operation of the display panel 702 and / or the functional circuit 739 (see S4 in Fig. 15(B)). In Fig. 15(A), an example where the ammeter 734 is connected to the wiring 772 is shown. However, the ammeter 734 may be connected to the wiring 771. Further, the power supply 733 and the ammeter 734 may be included in the liquid leakage detection circuit 732, and the liquid leakage detection circuit 732 may be electrically connected to the wirings 771 and 772 (see Fig. 15(C)).

[0228] In this case, the liquid leakage detection circuit 732 has a function of applying a predetermined voltage to the wirings 771 and 772 and a function of detecting the current flowing through the wirings 771 and 772. This embodiment can be appropriately combined with other embodiments.

[0229]

[0230] (Embodiment 3) (Embodiment 3) In this embodiment, a flexible power storage device, which is an aspect of the present invention, will be described with reference to Figs. 16 to 23. The power storage device of an aspect of the present invention may have a curved shape. Further, the power storage device of an aspect of the present invention has flexibility and may be used in both a curved state and a non-curved state.

[0231] 〈Configuration Example 1〉 Fig. 16(A) shows a perspective view of a secondary battery 200, and Fig. 16(B) shows a top view of the secondary battery 200.

[0232] Fig. 17(A) shows a cross-sectional view between the dashed-dotted lines C1 - C2 in Fig. 16(B), and Fig. 17( B) shows a cross-sectional view between the dashed-dotted lines C3 - C4 in Fig. 16(B). In Figs. 17(A ), (B), for clarity of the figure, some components are shown in an extracted manner.

[0233] The secondary battery 200 has a positive electrode 211, a negative electrode 215, and a separator 203. The secondary battery 200 further has a positive electrode lead 221, a negative electrode lead 225, and an exterior body 207.

[0234] The positive electrode 211 and the negative electrode 215 each have a current collector and an active material layer. The positive electrode 211 and the negative electrode 215 are arranged such that the active material layers face each other with the separator 203 in between. are.

[0235] The electrodes (positive electrode 211 and negative electrode 215) of the secondary battery 200 are preferably longer in the direction of curvature for those located on the outer diameter side than those located on the inner diameter side of the curvature. With such a configuration, when the secondary battery 200 is curved at a certain curvature, the ends of the positive electrode 211 and the negative electrode 215 can be aligned. That is, all regions of the positive electrode active material layer of the positive electrode 211 can be arranged to face the negative electrode active material layer of the negative electrode 215. Therefore, the positive electrode active material of the positive electrode 211 can contribute to the battery reaction without waste. Therefore, the capacity per unit volume of the secondary battery 200 can be increased. This configuration is particularly effective when the curvature of the secondary battery 200 is fixed when using the secondary battery 200. For this reason, the positive electrode active material of the positive electrode 211 can contribute to the battery reaction without waste. Therefore, the capacity per unit volume of the secondary battery 200 can be increased. This configuration is particularly effective when the curvature of the secondary battery 200 is fixed when using the secondary battery 200.

[0236] The positive electrode lead 221 is electrically connected to a plurality of positive electrodes 211. The negative electrode lead 225 is is electrically connected to a plurality of negative electrodes 215. The positive electrode lead 221 and the negative electrode lead 225 each have a sealing layer 220.

[0237] The exterior body 207 houses a plurality of positive electrodes 211, a plurality of negative electrodes 215, and a plurality of separators 203 and covers them. The secondary battery 200 has an electrolytic solution (not shown) in the region covered by the exterior body 207 . The secondary battery 200 is sealed by adhering three sides of the exterior body 207.

[0238] In FIGS. 17(A) and (B), an example is shown in which a plurality of strip-shaped separators 203 are used and one separator 203 is disposed between the positive electrode 211 and the negative electrode 2 15 respectively. However, one aspect of the present invention is not limited to this. By folding (it can also be said to be a bellows type) or winding a single sheet-shaped separator, the separator is positioned between the positive electrode and the negative electrode may be used.

[0239] For example, FIGS. 19(A) to (D) show a method for manufacturing the secondary battery 200. A cross-sectional view taken between the dashed-dotted lines C1 - C2 in FIG. 16(B) when this manufacturing method is used is shown in FIG. 18.

[0240] First, the negative electrode 215 is disposed on the separator 203 (FIG. 19(A)). At this time, the negative electrode active material layer included in the negative electrode 215 is disposed so as to overlap the separator 203.

[0241] Next, the separator 203 is bent and the separator 203 is placed on top of the negative electrode 215. Next , the positive electrode 211 is placed on top of the separator 203 (FIG. 19(B)). At this time, the positive electrode active material layer included in the positive electrode 21 1 is disposed so as to overlap the separator 203 and the negative electrode active material layer. When using an electrode in which an active material layer is formed on one side of the current collector, the positive electrode 211 ​ The positive electrode active material layer and the negative electrode active material layer of the negative electrode 215 are arranged to face each other with the separator 203 interposed therebetween. Place.

[0242] When the separator 203 is made of a material that can be heat-sealed, such as polypropylene, The overlapping areas of the electrodes 203 are thermally welded together, and then the next electrode is placed on top of the electrode. Specifically, the negative electrode 215 or the positive electrode 211 is overlapped with the negative electrode 215 or the positive electrode 211, so that the electrode can be prevented from shifting during the process. In the region where the separators 203 overlap each other, for example, the region 203 in FIG. It is preferable to heat weld the area indicated by a.

[0243] By repeating this process, a positive electrode 203 is sandwiched between the separator 203 as shown in FIG. 19(C). 211 and the anode 215 can be stacked.

[0244] In addition, a plurality of negative electrodes 215 and a plurality of negative electrodes 215 are attached to the separator 203 which has been repeatedly folded in advance. The positive electrodes 211 may be arranged so as to be sandwiched alternately.

[0245] Next, as shown in FIG. 19(C), a plurality of positive electrodes 211 and a plurality of negative electrodes are bonded to a separator 203. Covers 215.

[0246] Furthermore, as shown in FIG. 19(D), in a region where the separators 203 overlap each other, for example, By thermally welding the region 203b shown in FIG. 19(D), a plurality of positive electrodes 211 and a plurality of negative electrodes 2 15 is covered with a separator 203 and bound.

[0247] The positive electrodes 211, the negative electrodes 215, and the separator 203 are bound together using a binding material. May be bundled.

[0248] In order to stack the positive electrode 211 and the negative electrode 215 in such a process, the separator 203 is located between a plurality of positive electrodes 211 and a plurality of negative electrodes 215 in one sheet of the separator 203, and has a region covered so as to cover the plurality of positive electrodes 211 and the plurality of negative electrodes 215. That is, the separator 203 included in the secondary battery 200 shown in FIGS. 18 and 19(D) is one sheet of separator partially folded. A plurality of positive electrodes 211 and a plurality of negative electrodes 215 are sandwiched in the folded region of the separator 203.

[0249] In other words, the separator 203 included in the secondary battery 200 shown in FIGS. 18 and 19(D) is one sheet of separator partially folded. A plurality of positive electrodes 211 and a plurality of negative electrodes 215 are sandwiched in the folded region of the separator 203. sheet of separator partially folded. A plurality of positive electrodes 211 and a plurality of negative electrodes 215 are sandwiched in the folded region of the separator 203. That is, the separator 203 included in the secondary battery 200 shown in FIGS. 18 and 19(D) is one sheet of separator partially folded. A plurality of positive electrodes 211 and a plurality of negative electrodes 215 are sandwiched in the folded region of the separator 203.

[0250] <Constitution Example 2> FIG. 20(A) shows a perspective view of the secondary battery 250, and FIG. 20(B) shows a top view of the secondary battery 250. FIG. 20(C1) shows a cross-sectional view of the first electrode assembly 230, and FIG. 20(C2 ) shows a cross-sectional view of the second electrode assembly 231.

[0251] The secondary battery 250 includes a first electrode assembly 230, a second electrode assembly 231, and a separator 203. The secondary battery 250 further includes a positive electrode lead 221, a negative electrode lead 225, and an exterior body 207.

[0252] As shown in FIG. 20(C1), in the first electrode assembly 230, the positive electrode 211a, the separator 2 03, the negative electrode 215a, the separator 203, and the positive electrode 211a are laminated in this order. The positive electrode 211a and the negative electrode 215a each have an active material layer on both sides of a current collector.

[0253] As shown in FIG. 20(C2), in the second electrode assembly 231, the negative electrode 215a, the separator 2 03, the positive electrode 211a, the separator 203, and the negative electrode 215a are laminated in this order.​ The positive electrode 211a and the negative electrode 215a each have an active material layer on both sides of the current collector. That is.

[0254] In the first electrode assembly 230 and the second electrode assembly 231, the positive electrode and the negative electrode are arranged such that the active material layers face each other with the separator 203 in between.

[0255] The positive electrode lead 221 is electrically connected to a plurality of positive electrodes 211. The negative electrode lead 225 is electrically connected to a plurality of negative electrodes 215. The positive electrode lead 221 and the negative electrode lead 225 each have a sealing layer 220.

[0256] FIG. 21 shows an example of a cross-sectional view between the dashed-dotted lines D1 - D2 in FIG. 20(B). Note that in FIG. 21, for clarity of the drawing, some of the components are shown in an extracted manner.

[0257] As shown in FIG. 21, the secondary battery 250 has a configuration in which a plurality of first electrode assemblies 230 and a plurality of second electrode assemblies 231 are covered by a wound separator 203.

[0258] The exterior body 207 covers the plurality of first electrode assemblies 230, the plurality of second electrode assemblies 231, and the separator 203. The secondary battery 200 has an electrolytic solution (not shown in the figure) in the region covered by the exterior body 207. The secondary battery 200 is sealed by adhering three sides of the exterior body 207. That is, the secondary battery 200 is sealed by adhering three sides of the exterior body 207. That is.

[0259] For example, FIGS. 22(A) to (D) show a method for manufacturing the secondary battery 250.

[0260] First, the first electrode assembly 230 is disposed on the separator 203 (FIG. 22(A)).

[0261] Next, the separator 203 is bent, and the separator 203 is placed on the first electrode assembly 230. Next, two sets of second electrode assemblies 231 are stacked on the top and bottom of the first electrode assembly 230 with the separator 203 interposed therebetween (FIG. 22(B)).

[0262] Next, the separator 203 is wound so as to cover the two sets of second electrode assemblies 231. Further, two sets of first electrode assemblies 230 are stacked on the top and bottom of the two sets of second electrode assemblies 231 with the separator 203 interposed therebetween (FIG. 22(C)).

[0263] Next, the separator 203 is wound so as to cover the two sets of first electrode assemblies 230 (FIG. 22(D)).

[0264] In such a process, a plurality of first electrode assemblies 230 and a plurality of second electrode assemblies 231 are stacked on top of each other, so these electrode assemblies are disposed between the separators 203 wound in a spiral shape.

[0265] Note that it is preferable that the electrode disposed on the outermost side does not have an active material layer on the outside.

[0266] Also, in FIGS. 20(C1) and (C2), the electrode assembly is shown having a configuration of three electrodes and two separators, but one aspect of the present invention is not limited thereto. A configuration having four or more electrodes and three or more separators may be used. By increasing the number of electrodes, the capacity of the secondary battery 250 can be further improved. Also, a configuration having two electrodes and one separator may be used. When the number of electrodes is small, a secondary battery that is more resistant to bending can be obtained. Also, in FIG. 21, the secondary battery 250 is shown having a configuration of three sets of first electrode assemblies 230 and two sets of second electrode assemblies 231. ​​​​​​​​​​​However, one aspect of the present invention is not limited to this. A configuration having more electrode assemblies is also acceptable. By increasing the number of electrode assemblies, the capacity of the secondary battery 250 can be further improved . Also, a configuration having fewer electrode assemblies is also acceptable. When the number of electrode assemblies is small, a secondary battery that is more resistant to bending can be obtained.

[0267] Also, FIG. 23 shows another example of a cross-sectional view between the dashed-dotted lines D1 - D2 in FIG. 20(B). As shown in FIG. 23, by folding the separator 203 in a bellows shape, the separator 203 may be disposed between the first electrode assembly 230 and the second electrode assembly 231.

[0268] This embodiment can be appropriately combined with other embodiments.

[0269] (Embodiment 4) In this embodiment, an example of the use of the power storage device according to one aspect of the present invention will be described with reference to FIGS. 24 to 28.

[0270] The power storage device according to one aspect of the present invention can be used, for example, in electronic devices and lighting devices. The power storage device according to one aspect of the present invention has excellent charge and discharge characteristics. Therefore, electronic devices and lighting devices can be used for a long time with a single charge. Also, since the decrease in capacity due to charge and discharge cycles is suppressed, the usable time is less likely to be shortened even when charging is repeated. Further, the power storage device according to one aspect of the present invention exhibits excellent charge and discharge characteristics in a wide temperature range including a high-temperature environment, and has high long-term reliability and safety. Therefore, the safety and reliability of electronic devices and lighting devices can be enhanced.

[0271] Examples of electronic devices include, for example, television devices (also referred to as TVs or television receivers). ​​(u), monitors for computers, digital cameras, digital video cameras, digital photo frames, mobile phones (also referred to as mobile telephones and mobile phone devices), portable game machines, port able information terminals, audio playback devices, large game machines such as pachinko machines, etc.

[0272] Since the power storage device according to one aspect of the present invention has flexibility, the power storage device itself, or an electronic device or lighting device using the power storage device, can also be incorporated along the inner wall or outer wall of a house or building, or along the curved surface of the interior or exterior of an automobile. Figure 24(A) shows an example of a mobile phone. The mobile phone 7400 includes a display unit 7402 incorporated in a housing 7401, 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.

[0273] Figure 24(B) shows a state where the mobile phone 7400 is bent. When the mobile phone 7400 is deformed by an external force to be bent as a whole, the power storage device 7407 provided inside it also bends. The power storage device 7407 is a thin power storage device. The power storage device 7407 is fixed in a bent state. The bent state of the power storage device 7407 is shown in Figure 24(C). Figure 24(D) shows an example of a bangle-type display device. The portable display device 7100 includes a housing 7101, a display unit 7102, operation buttons 7103, and a power storage device 7104. Figure 24(E) shows the state of the bent power storage device 7104.

[0274]

[0275]

[0276] ​​​​​​​​​FIG. 24(F) shows an example of a wristwatch-type portable information terminal. The portable information terminal 7200 , includes a housing 7201, a display unit 7202, a band 7203, a buckle 7204, operation buttons 72 05, input / output terminals 7206, etc.

[0277] The portable information terminal 7200 can execute various applications such as mobile phones, e-mails, text viewing and creation, music playback, Internet communication, computer games, etc. .

[0278] The display unit 7202 is provided with a curved display surface and can perform display along the curved display surface. In addition, the display unit 7202 is provided with a touch sensor and can be operated by touching the screen with a finger or a stylus. For example, an application can be launched by touching the icon 72 07 displayed on the display unit 7202.

[0279] In addition to time setting, the operation buttons 7205 can perform various functions such as turning on and off the power, turning on and off wireless communication, executing and canceling the silent mode, and executing and canceling the power saving mode. For example, the functions of the operation buttons 7205 can also be freely set by the operating system incorporated in the portable information terminal 7200. .

[0280] In addition, the portable information terminal 7200 can perform communication-standard short-range wireless communication. For example, it can communicate with a wireless headset to make hands-free calls. .

[0281] In addition, the portable information terminal 7200 is provided with input / output terminals 7206 and can be connected to other information terminals with a connector. It is possible to directly exchange data through it. Also, charging can be performed via the input / output terminal 7206. It is also possible to perform charging. Note that the charging operation may be performed by wireless power supply without using the input / output terminal 7206. It may be like this.

[0282] The display unit 7202 of the portable information terminal 7200 has a power storage device according to an aspect of the present invention. For example, the power storage device 7104 shown in FIG. 24(E) can be incorporated in a curved state inside the housing 7201 or in a state where it can be curved inside the band 7203.

[0283] FIG. 25(A) shows an example of a wrist-mounted activity meter. The activity meter 7250 includes a housing 7251, a band 7203, a buckle 7204, etc. Also, inside the housing 7251 a wireless communicator, a pulse sensor, an acceleration sensor, a temperature sensor, etc. are provided. The activity meter 7250 acquires information such as the change in the wearer's pulse and activity level by the pulse sensor and the acceleration sensor, and has a function of transmitting this information to an external portable information terminal by the wireless communicator. Also, the activity meter 7 250 may have a function of measuring the wearer's calorie consumption and calorie intake, a function of acquiring the number of steps, a function of measuring the sleep state, etc. Note that the activity meter 7250 may have a display unit and be able to display the information acquired by the above functions.

[0284] The activity meter 7250 has a power storage device according to an aspect of the present invention. For example, the power storage device 7104 shown in FIG. 24(E) can be incorporated in a curved state inside the housing 7201 or in a state where it can be curved inside the band 7203.

[0285] FIG. 25(B) shows an example of a bracelet-type display device. The display device 7300 has a display unit 7 It has 304 and has the power storage device of one aspect of the present invention. Further, the display device 7300 may include a touch sensor in the display unit 7304, and may also function as a portable information terminal. The display surface of the display unit 7304 is curved, and display can be performed along the curved display surface. Further, the display device 7300 can change the display situation by means of communication-standardized short-range wireless communication or the like.

[0286] The display surface of the display unit 7304 is curved, and display can be performed along the curved display surface. Further, the display device 7300 can change the display situation by means of communication-standardized short-range wireless communication or the like. The display device 7300 is provided with input / output terminals and can directly exchange data with other information terminals via a connector. Charging can also be performed via the input / output terminals.

[0287] The display device 7300 is provided with input / output terminals and can directly exchange data with other information terminals via a connector. Charging can also be performed via the input / output terminals. Note that the charging operation may be performed by wireless power supply without passing through the input / output terminals. Note that the charging operation may be performed by wireless power supply without passing through the input / output terminals.

[0288] FIG. 25(C) shows an example of a glasses-type display device. The display device 7350 has lenses 7351, frames 7352, and the like. Further, a projection unit (not shown) that projects an image or video onto the lens 7351 is provided inside the frame 7352 or in contact with the frame 7352. The display device 7350 has a function of displaying the image 7351A in a direction in which the wearer can visually recognize it over the entire lens 7351. Or, it has a function of displaying the image 7351B in a direction in which the wearer can visually recognize it on a part of the lens 7351. The display device 7350 has a function of displaying the image 7351A in a direction in which the wearer can visually recognize it over the entire lens 7351. Or, it has a function of displaying the image 7351B in a direction in which the wearer can visually recognize it on a part of the lens 7351. The display device 7350 has a function of displaying the image 7351A in a direction in which the wearer can visually recognize it over the entire lens 7351. Or, it has a function of displaying the image 7351B in a direction in which the wearer can visually recognize it on a part of the lens 7351. The display device 7350 has a function of displaying the image 7351A in a direction in which the wearer can visually recognize it over the entire lens 7351. Or, it has a function of displaying the image 7351B in a direction in which the wearer can visually recognize it on a part of the lens 7351. The display device 7350 has a function of displaying the image 7351A in a direction in which the wearer can visually recognize it over the entire lens 7351. Or, it has a function of displaying the image 7351B in a direction in which the wearer can visually recognize it on a part of the lens 7351.

[0289] The display device 7350 has the power storage device of one aspect of the present invention. FIG. 25(D) shows an enlarged view of the tip portion 7355 of the frame 7352. The tip portion 7355 can be formed of a rubber material such as fluororubber or silicone rubber. Inside the tip portion 7355 is the power storage device of one aspect of the present invention. The tip portion 7355 can be formed of a rubber material such as fluororubber or silicone rubber. Inside the tip portion 7355 is the power storage device of one aspect of the present invention. The placement 7360 is embedded, and the positive electrode lead 7361 and the negative electrode lead 7362 protrude from the tip 735 5. The positive electrode lead 7361 and the negative electrode lead 7362 are electrically connected to the wiring provided inside the frame 735 2 and connected to the projection part and other connection parts. Note that the tip 73 55 can be manufactured by integral formation as described in the second embodiment together with the power storage device 7360 and so on.

[0290] The tip 7355 and the power storage device 7360 have flexibility. Therefore, the display device 7350 can be worn so as to closely adhere to the shape of the user's head.

[0291] Figures 26(A) and (B) show an example of a foldable tablet terminal. Figure 26(A) , (B) The tablet terminal 9600 shown has a pair of housings 9630, a pair of housings 9630 connected by a movable part 9640, a display part 9631a, a display part 9631b, a display mode switching switch 9626, a power switch 9627, a power saving mode switching switch 9625, a lock tool 9629, and an operation switch 9628. Figure 26(A) shows the state where the tablet terminal 96 00 is opened, and Figure 26(B) shows the state where the tablet terminal 9600 is closed is shown.

[0292] In addition, the tablet terminal 9600 has a power storage body 9635 inside the housing 9630. The power storage body 9635 is provided through the movable part 9640 and extends from one housing 9630 to the other housing 9630 .

[0293] A part of the display part 9631a can be a touch panel area 9632a, and data can be input by touching the displayed operation key 9638. Note that the display part 963 In 1a, as an example, a configuration is shown where half of the area has only a display function and the remaining half has a touch panel function, but it is not limited to this configuration. All areas of the display unit 9631a may have a touch panel function. For example, keyboard buttons can be displayed on the entire surface of the display unit 9631a to serve as a touch panel, and the display unit 9631b can be used as a display screen. Moreover, in the display unit 9631b as well, similar to the display unit 9631a, a part of the display unit 9631b can be made into the touch panel area 9632b. Also, by touching the position where the keyboard display switching button 9639 of the touch panel is displayed with a finger or a stylus, etc., keyboard buttons can be displayed on the display unit 9631b. In addition, simultaneous touch input can be performed on the touch panel area 9632a and the touch panel area 9632b. The display mode switching switch 9626 can select switching of the display orientation such as vertical display or horizontal display, switching between black and white display and color display, etc. The power saving mode switching switch 9625 can optimize the display brightness according to the amount of external light detected by the optical sensor built into the tablet terminal 9600 during use. The tablet terminal may incorporate other detection devices such as sensors for detecting inclination such as a gyro and an acceleration sensor in addition to the optical sensor. Also, in Fig. 26(A), an example is shown where the display areas of the display unit 9631a and the display unit 9631b are the same.

[0294] Furthermore, in the display unit 9631b, similar to the display unit 9631a, a part of the display unit 9631b can be made into the touch panel area 9632b. Also, by touching the position where the keyboard display switching button 9639 of the touch panel is displayed with a finger or a stylus, etc., keyboard buttons can be displayed on the display unit 9631b. Moreover, in the display unit 9631b, similar to the display unit 9631a, a part of the display unit 9631b can be made into the touch panel area 9632b. Also, by touching the position where the keyboard display switching button 9639 of the touch panel is displayed with a finger or a stylus, etc., keyboard buttons can be displayed on the display unit 9631b. In addition, simultaneous touch input can be performed on the touch panel area 9632a and the touch panel area 9632b. The display mode switching switch 9626 can select switching of the display orientation such as vertical display or horizontal display, switching between black and white display and color display, etc. The power saving mode switching switch 9625 can optimize the display brightness according to the amount of external light detected by the optical sensor built into the tablet terminal 9600 during use. The tablet terminal may incorporate other detection devices such as sensors for detecting inclination such as a gyro and an acceleration sensor in addition to the optical sensor.

[0295] In addition, simultaneous touch input can be performed on the touch panel area 9632a and the touch panel area 9632b. The display mode switching switch 9626 can select switching of the display orientation such as vertical display or horizontal display, switching between black and white display and color display, etc. The power saving mode switching switch 9625 can optimize the display brightness according to the amount of external light detected by the optical sensor built into the tablet terminal 9600 during use. The tablet terminal may incorporate other detection devices such as sensors for detecting inclination such as a gyro and an acceleration sensor in addition to the optical sensor.

[0296] The display mode switching switch 9626 can select switching of the display orientation such as vertical display or horizontal display, switching between black and white display and color display, etc. The power saving mode switching switch 9625 can optimize the display brightness according to the amount of external light detected by the optical sensor built into the tablet terminal 9600 during use. The tablet terminal may incorporate other detection devices such as sensors for detecting inclination such as a gyro and an acceleration sensor in addition to the optical sensor. The display mode switching switch 9626 can select switching of the display orientation such as vertical display or horizontal display, switching between black and white display and color display, etc. The power saving mode switching switch 9625 can optimize the display brightness according to the amount of external light detected by the optical sensor built into the tablet terminal 9600 during use. The tablet terminal may incorporate other detection devices such as sensors for detecting inclination such as a gyro and an acceleration sensor in addition to the optical sensor. The power saving mode switching switch 9625 can optimize the display brightness according to the amount of external light detected by the optical sensor built into the tablet terminal 9600 during use. The tablet terminal may incorporate other detection devices such as sensors for detecting inclination such as a gyro and an acceleration sensor in addition to the optical sensor. The display mode switching switch 9626 can select switching of the display orientation such as vertical display or horizontal display, switching between black and white display and color display, etc. The power saving mode switching switch 9625 can optimize the display brightness according to the amount of external light detected by the optical sensor built into the tablet terminal 9600 during use. The tablet terminal may incorporate other detection devices such as sensors for detecting inclination such as a gyro and an acceleration sensor in addition to the optical sensor. The display mode switching switch 9626 can select switching of the display orientation such as vertical display or horizontal display, switching between black and white display and color display, etc. The power saving mode switching switch 9625 can optimize the display brightness according to the amount of external light detected by the optical sensor built into the tablet terminal 9600 during use. The tablet terminal may incorporate other detection devices such as sensors for detecting inclination such as a gyro and an acceleration sensor in addition to the optical sensor. The display mode switching switch 9626 can select switching of the display orientation such as vertical display or horizontal display, switching between black and white display and color display, etc. The power saving mode switching switch 9625 can optimize the display brightness according to the amount of external light detected by the optical sensor built into the tablet terminal 9600 during use. The tablet terminal may incorporate other detection devices such as sensors for detecting inclination such as a gyro and an acceleration sensor in addition to the optical sensor.

[0297] In Fig. 26(A), an example is shown where the display areas of the display unit 9631a and the display unit 9631b are the same. although it is not particularly limited, the size of one display unit may be different from the size of the other display unit, and it may also be the case that the display quality is different. For example, one may be capable of performing a higher-definition display than the other as a display panel.

[0298] FIG. 26(B) shows a closed state, and the tablet-type terminal has a charge / discharge control circuit 9634 including a housing 9630, a solar cell 96 33, and a DCDC converter 9636. Further, as the power storage body 9635, a power storage device according to one aspect of the present invention is used.

[0299] Note that since the tablet-type terminal 9600 is foldable in two, when not in use, the pair of housings 9630 can be folded so as to overlap each other. By folding, the display units 9631a , 9631b can be protected, thus enhancing the durability of the tablet-type terminal 9600. In addition, the power storage body 9635 using a power storage body according to one aspect of the present invention has flexibility, and the charge / discharge capacity is less likely to decrease even when repeated bending and stretching are performed. Therefore, a tablet-type terminal with excellent reliability can be provided.

[0300] In addition, the tablet-type terminal shown in FIGS. 26(A) and (B) also has functions such as displaying various information (still images, videos, text images, etc.) on the display unit, displaying a calendar, date, or time, etc. on the display unit, a touch input function for touch input operation or editing of the information displayed on the display unit, a function for controlling processing by various software (programs), etc.

[0301] Power can be supplied to the touch panel, display unit, or video signal processing unit, etc. by the solar cell 9633 mounted on the surface of the tablet-type terminal. Note that the solar cell 9633 is housed It can be provided on one or both sides of the body 9630, and is suitable because it can be configured to efficiently charge the power storage body 9635. Note that as the power storage body 9635, using a lithium-ion battery has advantages such as enabling miniaturization.

[0302] Also, regarding the configuration and operation of the charge / discharge control circuit 9634 shown in FIG. 26(B), a block diagram is shown and explained in FIG. 26(C). FIG. 26(C) shows the solar cell 9633, the power storage body 9635, the DCDC converter 9636, the converter 9637, the switches SW1 to SW3, and the display unit 9631. The power storage body 9635, the DCDC converter 9636, the converter 9637, and the switches SW1 to SW3 correspond to the parts of the charge / discharge control circuit 9634 shown in FIG. 26(B).

[0303] First, an example of the operation when power is generated by the solar cell 9633 due to external light will be described. The power generated by the solar cell is stepped up or down by the DCDC converter 9636 to become a voltage for charging the power storage body 9635. When the power from the solar cell 9633 is used for the operation of the display unit 9631, the switch SW1 is turned on, and the converter 9637 steps up or down the voltage to the required voltage for the display unit 9631. When the display on the display unit 9631 is not performed, the switch SW1 is turned off, and the switch SW2 is turned on to charge the power storage body 9635.

[0304] Note that the solar cell 9633 is shown as an example of a power generation means, but it is not particularly limited, and power storage can be performed by other power generation means such as piezoelectric elements (piezo elements) and thermoelectric conversion elements (Peltier elements). It may be configured to charge the electrical body 9635. For example, power is transmitted and received wirelessly (non - contact) and charged, or a contactless power transmission module and other charging means may be combined. This may also be done.

[0305] Fig. 27 shows an example of another electronic device. In Fig. 27, the display device 8000 is an example of an electronic device using the power storage device 8004 according to one aspect of the present invention. Specifically, the display device 800 0 corresponds to a display device for receiving TV broadcasts, and includes a housing 8001, a display unit 8002, a speaker unit 8003, a power storage device 8004, etc. The power storage device 8004 according to one aspect of the present invention is provided inside the housing 8001. The display device 8000 can be supplied with power from a commercial power supply, or can use the power stored in the power storage device 8004. Therefore, even when power supply from the commercial power supply cannot be received due to a power outage or the like, by using the power storage device 8004 according to one aspect of the present invention as an uninterruptible power supply, the display device 8000 can be used.

[0306] The display unit 8002 may be provided with a light - emitting element such as a liquid crystal display device, an organic EL element, etc. in each pixel, a light - emitting device, an electrophoretic display device, a DMD (Digital Micromirror Devi ce), a PDP (Plasma Display Panel), an FED (Field Emission Display), etc., and a semiconductor display device can be used.

[0307] Note that the display device includes all display devices for information display, such as for personal computers, advertising displays, etc., in addition to those for receiving TV broadcasts.

[0308] ​​​In FIG. 27, the installed lighting device 8100 is an example of an electronic device using the power storage device 81 03 according to one aspect of the present invention. Specifically, the lighting device 8100 includes a housing 8101, a light source 8102, a power storage device 8103, and the like. In FIG. 27, the case where the power storage device 8103 is provided inside the ceiling 81 01 and the light source 8102 are installed is illustrated as an example, but the power storage device 8103 may be provided inside the housing 8101. The lighting device 8100 can receive power supply from a commercial power source, or can use the power stored in the power storage device 8103 . Therefore, even when the power supply from the commercial power source cannot be received due to a power outage or the like, by using the power storage device 8103 according to one aspect of the present invention as an uninterruptible power supply , the lighting device 8100 can be used .

[0309] Note that in FIG. 27, the installed lighting device 8100 provided on the ceiling 8104 is illustrated , but the power storage device according to one aspect of the present invention can be used not only for the ceiling 8104 but also for installed lighting devices provided on, for example, side walls 8105, floors 8 106, windows 8107, etc., and can also be used for desktop type lighting devices and the like

[0310] In addition, as the light source 8102, an artificial light source that artificially obtains light using power can be used . Specifically, incandescent bulbs, discharge lamps such as fluorescent lamps, and light-emitting elements such as LEDs and organic EL elements can be cited as examples of the above artificial light sources

[0311] In FIG. 27, an air conditioner having an indoor unit 8200 and an outdoor unit 8204 is an example of an electronic device using the power storage device 8203 according to one aspect of the present invention. Specifically, the indoor The machine 8200 includes a housing 8201, an air outlet 8202, a power storage device 8203, etc. In FIG. 27 illustrates the case where the power storage device 8203 is provided in the indoor unit 8200. However, the power storage device 8203 may be provided in the outdoor unit 8204. Alternatively, the power storage device 8203 may be provided in both the indoor unit 8200 and the outdoor unit 8204. The air conditioner can receive power supply from the commercial power supply, and can also use the power stored in the power storage device 8203. In particular, when the power storage device 82 03 is provided in both the indoor unit 8200 and the outdoor unit 8204, even when the power supply from the commercial power supply cannot be received due to a power outage or the like the air conditioner can be used by using the power storage device 8203 according to one aspect of the present invention as an uninterruptible power supply.

[0312] Note that in FIG. 27, a separate type air conditioner composed of an indoor unit and an outdoor unit is illustrated. However, the power storage device according to one aspect of the present invention can also be used for an integrated type air conditioner having the functions of the indoor unit and the outdoor unit in one housing.

[0313] In FIG. 27, the electric refrigerator 8300 is an example of an electronic device using the power storage device 8304 according to one aspect of the present invention. Specifically, the electric refrigerator 8300 includes a housing 8301, a door for the storage room 8302, a door for the freezer 8303, a power storage device 8304, etc. In FIG. 27, the power storage device 8304 is provided inside the housing 8301. The electric refrigerator 8300 can receive power supply from the commercial power supply, and can also use the power stored in the power storage device 8304 Therefore, when the power supply from the commercial power supply cannot be received due to a power outage or the like However, by using the power storage device 8304 according to one aspect of the present invention as an uninterruptible power supply, the use of the electric refrigerator 8300 becomes possible.

[0314] Note that electronic devices such as a microwave oven and an electric rice cooker require high power in a short time. Therefore, by using the power storage device according to one aspect of the present invention as an auxiliary power supply for supplementing power that cannot be covered by the commercial power supply, it is possible to prevent the voltage of the commercial power supply from dropping when the electronic device is in use.

[0315] Also, during a time period when the electronic device is not in use, particularly during a time period when the ratio of the actually used amount of power to the total amount of power that can be supplied by the commercial power supply source (referred to as the power usage rate) is low, by storing power in the power storage device, it is possible to suppress an increase in the power usage rate outside the above time period. For example, in the case of the electric refrigerator 8300, power is stored in the power storage device 8304 at night when the temperature is low and the doors 8302 for the refrigerator compartment and 8303 for the freezer compartment are not opened or closed. Then, during the day when the temperature rises and the doors 8302 for the refrigerator compartment and 8303 for the freezer compartment are opened or closed, by using the power storage device 8304 as an auxiliary power supply, the power usage rate during the day can be kept low.

[0316] Also, the power storage device according to one aspect of the present invention can be mounted on a vehicle.

[0317] When the power storage device is mounted on a vehicle, next-generation clean energy vehicles such as a hybrid electric vehicle (HEV), an electric vehicle (EV), or a plug-in hybrid electric vehicle (PHEV) can be realized. .

[0318] ​Figures 28(A) and (B) illustrate a vehicle using a power storage device according to an aspect of the present invention. Figure 28( The automobile 8400 shown in A) is an electric vehicle that uses an electric motor as a power source for driving. Alternatively, it is a hybrid vehicle that can appropriately select and use an electric motor and an engine as power sources for driving. By using an aspect of the present invention, a vehicle with a long cruising range can be realized. In addition, the automobile 8400 has a power storage device. The power storage device can not only drive the electric motor, but also supply power to lighting devices such as headlights 8401 and room lights (not shown).

[0319] In addition, the power storage device can supply power to display devices such as a speedometer and a tachometer that the automobile 8400 has. In addition, the power storage device can supply power to semiconductor devices such as a navigation system that the automobile 8400 has.

[0320] The automobile 8500 shown in Figure 28(B) can be charged by receiving power supply from an external charging facility by a plug-in method, a non-contact power supply method, or the like to the power storage device that the automobile 8500 has. Figure 28(B) shows a state in which charging is being performed from a ground-mounted charging device 8021 to a power storage device mounted on the automobile 8500 via a cable 8022. When charging, the charging method, the connector standard, 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 be a household power source. For example, by plug-in technology, the power storage device mounted on the automobile 8500 can be charged by external power supply. Charging can be performed by AC-DC It can be performed by converting AC power into DC power through a conversion device such as a converter.

[0321] Also, although not shown, a power receiving device is mounted on the vehicle, and power is supplied to the vehicle wirelessly from a power transmission device on the ground. In this case of the wireless power supply method, by embedding the power transmission device in a road or an outer wall, charging can be performed not only while the vehicle is stopped but also while it is running. Further, power can be transmitted and received between vehicles using this wireless power supply method. Additionally, 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 wireless power supply, an electromagnetic induction method or a magnetic field resonance method can be used. According to one aspect of the present invention, the cycle characteristics of the power storage device can be improved, and the reliability can be enhanced. Also, 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 the 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 the commercial power supply during the peak of the power demand.

[0322]

[0323] This embodiment can be appropriately combined with other embodiments.

Example

[0324] In this example, a power storage device according to one aspect of the present invention was fabricated, and the results of evaluating its characteristics will be described.

[0325] In this example, the power storage device 500 shown in Fig. 1(A) was fabricated.

[0326] The samples of this example are eight samples A1, A2, B1, B2, C1, C2, D1, and D2 to which one aspect of the present invention is applied. , and there are a total of 8.

[0327] In each sample prepared in this example, one positive electrode having a positive electrode active material layer on one side of the positive electrode current collector and , one negative electrode having a negative electrode active material layer on one side of the negative electrode current collector was used. That is, each test sample of this example has a configuration having one layer of positive electrode active material layer and one layer of negative electrode active material layer.

[0328] First, the method for manufacturing the electrode will be described.

[0329] [Method for manufacturing negative electrode] The method for manufacturing the negative electrode is common to all the samples of this example.

[0330] As the negative electrode active material, spherical natural graphite (manufactured by Nippon Graphite Industries Co., Ltd., CGB-15) having a specific surface area of 6.3 m 2 / g and an average particle diameter of 15 μm was used. In addition, carboxymethyl cellulose sodium (CMC-Na) and SBR were used as the binder. The degree of polymerization of the CMC-Na used was 6 00 or more and 800 or less, and the aqueous solution viscosity when used as a 1 wt% aqueous solution was in the range of 300 mPa·s or more and 500 mPa·s or less. The blending ratio of graphite, CMC-Na, and SBR was graphite:CMC-Na:SBR = 97:1.5:1.5 (wt%). First, the powder of CMC-Na and the active material were mixed and kneaded with a kneader to obtain a first mixture.

[0331] Next, a small amount of water was added to the first mixture and solid kneading was performed to obtain a second mixture. Here,

[0332] solid kneading refers to kneading due to high viscosity. Solid kneading is kneading due to high viscosity.

[0333] Next, water was further added and kneaded using a kneader to obtain a third mixture.

[0334] Next, 50 wt% aqueous dispersion of SBR was added and kneaded using a kneader. Then, defoaming was carried out under reduced pressure to obtain a slurry.

[0335] Next, the slurry was applied to the negative electrode current collector using a continuous coater. A rolled copper foil with a film thickness of 18 μm was used for the negative electrode current collector. The coating speed was set to 0.75 m / min.

[0336] Next, the solvent of the slurry applied on the negative electrode current collector was vaporized using a drying furnace. First, treatment was carried out at 50 °C for 120 seconds under an air atmosphere, and then treatment was carried out at 80 °C for 120 seconds Thereafter. Further, treatment was carried out at 100 °C for 10 hours under a reduced pressure atmosphere (gauge pressure of -100 kPa) was carried out.

[0337] Through the above steps, a negative electrode active material layer was formed on one side of the negative electrode current collector to fabricate a negative electrode.

[0338] [Method for fabricating a positive electrode] The method for fabricating the positive electrode is common to all the samples in this example.

[0339] As the positive electrode active material, LiCoO₂ with a specific surface area of 0.21 m 2 / g and an average particle size of 10 μm was used, polyvinylidene fluoride (PVdF) was used as a binder, and acetylene black was used as a conductive assistant. The composition of LiCoO₂, PVdF, and acetylene black was LiCoO₂ : acetylene black: PVdF = 90:5:5 (wt%). : acetylene black: PVdF = 90:5:5 (wt%).

[0340] First, acetylene black and PVdF were mixed and kneaded using a kneader to obtain a first mixture was obtained.

[0341] Next, an active material was added to the first mixture to obtain a second mixture.

[0342] Next, N-methyl-2-pyrrolidone (NMP), which is a solvent, was added to the second mixture, and kneading was performed using a kneader. Through the above steps, a slurry was prepared.

[0343] Next, kneading was carried out using a large kneader.

[0344] Next, the slurry was applied to the positive electrode current collector using a continuous coater. As the positive electrode current collector, an aluminum current collector (film thickness 20 μm) was used. The coating speed was set to 0.2 m / min.

[0345] Thereafter, the solvent of the slurry applied on the positive electrode current collector was vaporized using a drying furnace. The vaporization of the solvent was carried out in an air atmosphere. After treatment at 70 °C for 7.5 minutes, treatment at 90 °C for 7.5 minutes was performed.

[0346] Next, a heat treatment was carried out at 170 °C for 10 hours under a reduced pressure atmosphere (gauge pressure -100 kPa). Thereafter, the positive electrode active material layer was pressed by the roll press method to be densified. Through the above steps, a positive electrode active material layer was formed on one side of the positive electrode current collector to fabricate a positive electrode.

[0347] Through the above steps, a positive electrode active material layer was formed on one side of the positive electrode current collector to fabricate a positive electrode.

[0348] The average values of the active material loading, film thickness, and density of the fabricated positive electrode active material layer and negative electrode active material layer are shown in Table 1 In this specification, these values shown are the average values of each measurement value of the electrodes used when preparing the samples. When the active material layers are present on both sides of the current collector, these values correspond to the average values of the active material loading, film thickness, and density in the active material layer on one side.

[0349]

Table 1

[0350] As the electrolyte, a mixture of EC (ethylene carbonate) and PC (propylene carbonate) with a volume ratio of 1:1 was used as the solvent. As the solute and additive, the conditions shown in Table 2 were applied. Samples A1 and A2 (hereinafter, the electrolyte compositions of these samples are referred to as Condition A) were used. 1 mol / l of LiTFSA (lithium bis(trifluoromethanesulfonyl)amide) was used as the solute of the electrolyte, and 1 wt% of VC (vinylene carbonate) and 2 wt% of LiFSA (lithium bis(fluorosulfonyl)amide) were used as additives. Samples B1 and B2 (hereinafter referred to as Condition B) used 1 mol / l of LiFSA as the solute of the electrolyte and 1 wt% of VC as an additive. Samples C1 and C2 (hereinafter referred to as Condition C) used 1 mol / l of LiBETA (lithium bis(pentafluoroethanesulfonyl)amide) as the solute of the electrolyte and 1 wt% of VC as an additive. Samples D1 and D2 (hereinafter referred to as Condition D) used 1 mol / l of LiBETA as the solute of the electrolyte and 1 wt% of P S (propanesultone) as an additive. LiFSA was used as an additive in each sample of Condition A, and LiFSA was used as the solute in each sample of Condition B.

[0351]

[0352]

Table 2

[0352] Also, as the separator, a separator made of polyphenylene sulfide with a thickness of 46 μm (hereinafter also referred to as a PPS separator) with two sheets stacked was used.

[0353] ​In addition, for the exterior body, a film with resin layers coated on both sides of aluminum was used.

[0354] Next, the method for preparing the sample will be described.

[0355] First, the positive electrode, negative electrode, and separator were cut. The size of the positive electrode was 20.49 cm 2 , and the negative electrode had a size of 23.84 cm 2 .

[0356] Next, the positive electrode active material and negative electrode active material on the tab area were peeled off to expose the current collector.

[0357] Next, the positive electrode and negative electrode were laminated with the separator in between. At this time, the positive electrode and negative electrode were laminated such that the positive electrode active material layer and the negative electrode active material layer faced each other.

[0358] Next, leads were attached to the positive electrode and negative electrode by ultrasonic welding.

[0359] Next, leaving two sides out of the four sides of the exterior body, the exterior body was joined by heating.

[0360] Next, the sealing layer provided on the lead and the sealing layer of the exterior body were arranged to overlap and joined by heating. At this time, the parts other than the side where the electrolytic solution was to be injected were joined.

[0361] Next, a heating treatment for drying the exterior body, the positive electrode, separator, and negative electrode wrapped by the exterior body was performed. The heating conditions were 80 °C for 10 hours under a reduced-pressure atmosphere (gauge pressure of -100 kPa).

[0362] Next, approximately 600 μl of electrolytic solution was injected from the unsealed side under an argon gas atmosphere. Thereafter, one side of the exterior body was sealed by heating under a reduced-pressure atmosphere (gauge pressure of -60 kPa). Through the above steps, a thin power storage device was fabricated.

[0363] Next, heat treatment of Samples A2, B2, C2, and D2 was performed. The heating conditions were set to 170°C for 15 minutes in an atmospheric pressure atmosphere assuming integral formation with the fluororubber described in Embodiment 2. Specifically, after raising the temperature of the constant temperature bath to approximately 170°C, each sample was put into the constant temperature bath, and after 15 minutes, each sample was taken out. In this heat treatment, no expansion was observed inside the exterior body of each sample.

[0364] As described above, samples were prepared.

[0365] Next, the charge-discharge characteristics of each sample of this example at 25°C were evaluated. This measurement was performed using a charge-discharge measurement machine (manufactured by Toyo System Co., Ltd.). Constant current-constant voltage charging was performed with a maximum of 4.3V, and constant voltage discharging was performed with a minimum of 2.5V. Charge-discharge was performed at a rate of 0.1C, and a 10-minute rest time was provided after charging. Charge-discharge was performed for 2 cycles.

[0366]

[0366] ​

[0367] Figure 29(A) shows the charge-discharge curve of sample A1, Figure 29(B) shows that of sample A2, and Figure 29(C) shows that of sample B1 . Figure 29(D) shows the charge-discharge curve of sample B2. Also, Figure 30(A) shows that of sample C1 , Figure 30(B) shows that of sample C2, Figure 30(C) shows that of sample D1, and Figure 30(D) shows that of sample D 2. Figures 29(A) to 30(D) have the horizontal axis representing the capacity (mAh / g) and the vertical axis representing the voltage (V).

[0368] As shown in Figures 29(A) and (C), it can be seen that in samples A1, A2, B1, and B2, abnormalities occurred during the first charging, and the characteristics deteriorated rapidly during the first discharge. Also, further deterioration was observed during the second discharge. This is thought to indicate that LiTF SA and LiFSA, which are solutes of the electrolytic solution, corrode the aluminum of the positive electrode current collector when the positive electrode is at a high potential . Samples under condition A and condition B show similar characteristic abnormalities even when heat treatment is performed (see Figures 29(B) and (D)).

[0369] On the other hand, as shown in Figures 30(A) and (C), it can be seen that in samples C1, C2, D1, and D2, the first and second chargings were performed normally, and good charge-discharge characteristics were obtained . From this result, it can be seen that a power storage device using LiBETA as a solute can suppress the corrosion of the positive electrode current collector even during charge-discharge at a charging voltage of 4.3V and perform stable operation. Also, as shown in Figures 30(B ), (D), samples under condition C and condition D show a small decrease in capacity even when heat treatment is performed and normal charge-discharge characteristics are obtained, indicating high heat resistance. Table 3 shows the maintenance rate of the discharge capacity of samples under condition C and condition D due to heat treatment. The maintenance of the discharge capacity is shown. ​​ For the calculation of the retention rate, the second discharge capacity of each sample was used.

[0370] [Table 3]

[0371] From FIGS. 30(B), (D) and Table 3, it was found that the power storage device using the electrolytic solution of Condition D had the highest heat resistance and could obtain a high battery capacity. [Example] [Example]

[0372] In this example, the results of an experiment for confirming the surface state of the spherical natural graphite used as the negative electrode active material of the power storage device according to one aspect of the present invention will be described. The results of an experiment for confirming the surface state of the spherical natural graphite will be described.

[0373] [Cross-sectional TEM observation] A sample obtained by thinning a powder of spherical natural graphite by the focused ion beam (FIB) method was taken out and subjected to cross-sectional TEM (transmission electron microscope) observation. The apparatus used for the cross-sectional TEM observation was H-9000NAR manufactured by Hitachi High-Technologies Corporation, and the observation was carried out at an acceleration voltage of 2 00 kV. The obtained TEM images are shown in FIGS. 31(A) to (C). FIGS. 31(B), (C) are TEM images obtained by enlarging the regions 900 including the vicinity of the edge plane and the region 901 including the vicinity of the basal plane shown in FIG. 31(A), respectively. However, even on the plane regarded as the basal plane in the cross-sectional TEM observation, it is considered that minute edges exist. plane in the cross-sectional TEM observation, it is considered that minute edges exist. plane in the cross-sectional TEM observation, it is considered that minute edges exist.

[0374] Spherical natural graphite has a structure in which graphite layers are folded (see FIG. 31(A)). From FIGS. 31( B), (C), spherical natural graphite has, in both the vicinity of the edge plane and the vicinity of the basal plane, outside (the outermost surface layer) of the regularly arranged graphite layers 911, and has a crystallinity higher than that of the graphite layers 911. It can be seen that it has a low coating layer 912.

[0375] [Raman spectrum measurement] Next, the results of measuring the Raman spectrum by Raman spectroscopy will be described. For the measurement, , the microscopic Raman apparatus LabRAM of Horiba, Ltd. was used, and two-point measurements were performed on the powder of graphitized natural graphite. The wavelength of the laser used for Raman measurement was 532 nm.

[0376] The Raman measurement results of the powder of graphitized natural graphite are shown in Fig. 32. In Fig. 32, the D band (peak around 1360 cm in the Raman spectrum) indicating the disorder of the graphite crystal is clearly -1 observed. Also, the value (R value) of the intensity ratio of the G band (peak around 1580 cm in the Raman spectrum) to the D band is shown in Table 4. Corresponding to the clear observation of the D band, -1 the R value is a non-negligible value of 0.28 and 0.38. The fact that the R value is not small is considered to correspond to the fact that a layer with reduced crystallinity was observed on the surface of the graphitized natural graphite as shown in Figs. 31(B) and (C). It is considered that the layer with low crystallinity present on the outermost surface of the graphite particles, which is recognized by TEM observation and Raman spectroscopic analysis as shown in this example, may be able to suppress the insertion of PC into the graphite layer.

[0377]

Table 4

[0378] As shown in this example, the layer with low crystallinity present on the outermost surface of the graphite particles, which is recognized by TEM observation and Raman spectroscopic analysis, may be able to suppress the insertion of PC into the graphite layer.

Example

[0379] In this example, a power storage device according to one aspect of the present invention was fabricated, and the results of evaluating its characteristics will be described. ​​​​

[0380] In this example, a power storage device 500 shown in Fig. 1(A) was fabricated.

[0381] The samples of this example are a total of two samples E1 and E2 to which one aspect of the present invention is applied.

[0382] In each sample fabricated in this example, one positive electrode having a positive electrode active material layer on one side of the positive electrode current collector and one negative electrode having a negative electrode active material layer on one side of the negative electrode current collector were used. That is, each test sample of this example has a configuration having one layer of positive electrode active material layer and one layer of negative electrode active material layer.

[0383] First, the method for fabricating the electrodes will be described.

[0384] [Method for fabricating the negative electrode] The method for fabricating the negative electrode is common to all the samples of this example.

[0385] As the negative electrode active material, spherical natural graphite (manufactured by Nippon Graphite Industry Co., Ltd., CGB-15) having a specific surface area of 6.3 m 2 / g and an average particle diameter of 15 μm was used. Further, carboxymethyl cellulose sodium (CMC-Na) and SBR were used as the binder. The degree of polymerization of the CMC-Na used was 6 00 or more and 800 or less, and the aqueous solution viscosity when used as a 1 wt% aqueous solution was in the range of 300 mPa·s or more and 500 mPa·s or less. The blending ratio of graphite, CMC-Na, and SBR was graphite:CMC-Na:SBR = 97:1.5:1.5 (wt%). First, the powder of CMC-Na and the active material were mixed and kneaded with a kneader to obtain a first mixture.

[0386] Next, a small amount of water was added to the first mixture and solid kneading was performed to obtain a second mixture. Here,

[0387] Next, a small amount of water was added to the first mixture and solid kneading was performed to obtain a second mixture. Here, Solid kneading refers to kneading due to high viscosity.

[0388] Next, water was further added and kneaded using a kneader to obtain a third mixture.

[0389] Next, 50 wt% aqueous dispersion of SBR was added and kneaded using a kneader. Then, defoaming was carried out under reduced pressure to obtain a slurry.

[0390] Next, the slurry was applied to the negative electrode current collector using a continuous coater. A rolled copper foil with a film thickness of 18 μm was used for the negative electrode current collector. The coating speed was set to 0.75 m / min.

[0391] Next, the solvent of the slurry applied on the negative electrode current collector was vaporized using a drying furnace. First, treatment was carried out at 50 °C for 120 seconds under an air atmosphere, and then treatment was carried out at 80 °C for 120 seconds. Furthermore, treatment was carried out at 100 °C for 10 hours under a reduced pressure atmosphere (gauge pressure of -100 kPa).

[0392] Through the above steps, a negative electrode active material layer was formed on both sides of the negative electrode current collector to fabricate a negative electrode.

[0393] [Method for fabricating a positive electrode] The method for fabricating a positive electrode is common to all samples in this example.

[0394] As the positive electrode active material, LiCoO2 with an average particle size of 6 μm was used. As the binder, polyvinylidene fluoride (PVdF) was used, and as the conductive additive, acetylene black was used. The composition of LiCoO2, PVdF, and acetylene black was LiCoO2:acetylene black:PV dF = 95:3:2 (wt%).

[0395] First, acetylene black and PVdF were mixed and kneaded using a kneader to obtain a first mixture. ​​Ta.

[0396] Next, an active material was added to the first mixture to obtain a second mixture.

[0397] Next, N-methyl-2-pyrrolidone (NMP) as a solvent is added to the second mixture, and the mixture is kneaded. Through the above steps, a slurry was prepared.

[0398] Next, the mixture was mixed in a large mixer.

[0399] Next, the slurry was applied to the positive electrode current collector using a continuous coater. A lumi current collector (film thickness 20 μm) was used. The coating speed was 0.2 m / min.

[0400] Thereafter, the solvent of the slurry applied onto the positive electrode current collector was evaporated using a drying furnace. The oxidation was carried out in an air atmosphere, and the reaction was carried out at 70°C for 7.5 minutes, followed by treatment at 90°C for 7.5 minutes. Processing was carried out.

[0401] Next, heat treatment was performed at 170°C for 10 hours under a reduced pressure atmosphere (gauge pressure -100kPa). Thereafter, the positive electrode active material layer was pressed by a roll press method to be compacted.

[0402] Through the above steps, a positive electrode active material layer was formed on one surface of the positive electrode current collector, and a positive electrode was fabricated.

[0403] The average values of the active material loading amount, film thickness, and density of the prepared positive electrode active material layer and negative electrode active material layer are shown in Table 5. The values shown in this specification are based on the measurements of the electrodes used to prepare the samples. When the current collector has active material layers on both sides, these values are the average values of the active material layers on one side. It corresponds to the average value of the amount of active material carried, the thickness, and the density of the layer.

[0404]

Table 5

[0405] As the electrolytic solution, a mixture of EC (ethylene carbonate) and PC (propylene carbonate) with a volume ratio of 1:1 was used as the solvent. Also, 1 mol / l of LiBETA was used as the solute of the electrolytic solution, and 1 wt% of PS (propanesultone) was used as an additive. The conditions of the electrolytic solution are summarized in Table 6. The conditions of the electrolytic solutions of Samples E1 and E2 are the same as Condition D shown in Example 1. As the electrolytic solution, a mixture of EC (ethylene carbonate) and PC (propylene carbonate) with a volume ratio of 1:1 was used as the solvent. Also, 1 mol / l of LiBETA was used as the solute of the electrolytic solution, and 1 wt% of PS (propanesultone) was used as an additive. The conditions of the electrolytic solution are summarized in Table 6. The conditions of the electrolytic solutions of Samples E1 and E2 are the same as Condition D shown in Example 1. As the electrolytic solution, a mixture of EC (ethylene carbonate) and PC (propylene carbonate) with a volume ratio of 1:1 was used as the solvent. Also, 1 mol / l of LiBETA was used as the solute of the electrolytic solution, and 1 wt% of PS (propanesultone) was used as an additive. The conditions of the electrolytic solution are summarized in Table 6. The conditions of the electrolytic solutions of Samples E1 and E2 are the same as Condition D shown in Example 1. As the electrolytic solution, a mixture of EC (ethylene carbonate) and PC (propylene carbonate) with a volume ratio of 1:1 was used as the solvent. Also, 1 mol / l of LiBETA was used as the solute of the electrolytic solution, and 1 wt% of PS (propanesultone) was used as an additive. The conditions of the electrolytic solution are summarized in Table 6. The conditions of the electrolytic solutions of Samples E1 and E2 are the same as Condition D shown in Example 1. As the electrolytic solution, a mixture of EC (ethylene carbonate) and PC (propylene carbonate) with a volume ratio of 1:1 was used as the solvent. Also, 1 mol / l of LiBETA was used as the solute of the electrolytic solution, and 1 wt% of PS (propanesultone) was used as an additive. The conditions of the electrolytic solution are summarized in Table 6. The conditions of the electrolytic solutions of Samples E1 and E2 are the same as Condition D shown in Example 1.

[0406]

Table 6

[0407] Also, as the separator, a separator made of two layers of solvent-spun regenerated cellulose fibers with a thickness of 46 μm was used. Also, as the separator, a separator made of two layers of solvent-spun regenerated cellulose fibers with a thickness of 46 μm was used.

[0408] Also, for the exterior body, a film with a resin layer coated on both sides of aluminum was used.

[0409] Next, the method for preparing the samples will be described.

[0410] First, the positive electrode, negative electrode, and separator were cut. The size of the positive electrode was 20.49 cm 2 , and the size of the negative electrode was 23.84 cm 2 .

[0411] Next, the positive electrode active material and negative electrode active material on the tab region were peeled off to expose the current collector.

[0412] Next, the positive electrode and negative electrode were laminated with the separator in between. At this time, the positive electrode and negative electrode were laminated such that the positive electrode active material layer and the negative electrode active material layer faced each other. Next, the positive electrode and negative electrode were laminated with the separator in between. At this time, the positive electrode and negative electrode were laminated such that the positive electrode active material layer and the negative electrode active material layer faced each other.

[0413] Next, leads were attached to the positive electrode and the negative electrode by ultrasonic welding.

[0414] Next, the laminate of the positive electrode and the negative electrode was wrapped with a sheet made of polyphenylene sulfide. . This is to prevent the aluminum layer of the exterior body from being exposed by heat treatment of the battery and coming into contact with the positive electrode or the negative electrode to cause a short circuit.

[0415] Next, leaving two sides out of the four sides of the exterior body, the exterior body was joined by heating.

[0416] Next, they were arranged so that the sealing layer provided on the lead and the sealing layer of the exterior body overlapped, and were joined by heating. At this time, the sides other than the side where the electrolytic solution was to be injected were joined.

[0417] Next, a heat treatment for drying the exterior body and the positive electrode, separator, and negative electrode wrapped in the exterior body was performed. The heating conditions were 80 °C for 10 hours under a reduced-pressure atmosphere (gauge pressure of -100 kPa).

[0418] Next, about 600 μl of electrolytic solution was injected from the unsealed side under an argon gas atmosphere. Then, under a reduced-pressure atmosphere (gauge pressure of -100 kPa), one side of the exterior body was sealed by heating. Through the above steps, a thin power storage device was fabricated.

[0419] Next, a heat treatment of Sample E2 was performed. The heating conditions were 170 °C for 15 minutes under an atmospheric pressure atmosphere assuming the integral formation with fluororubber described in Embodiment 2. Specifically, after raising the temperature of the constant temperature bath to about 170 °C, the sample was put into the constant temperature bath, and the sample was taken out after 15 minutes. No expansion was observed inside the exterior body of the sample during this heat treatment.

[0420] ​​​​​​​​​As described above, samples were prepared.

[0421] Next, the charge-discharge characteristics of each sample of this example at 25°C were evaluated. The measurement was performed using a charge-discharge measurement machine (manufactured by Toyo System Co., Ltd.). Constant current-constant voltage charging was performed with 4.3V as the upper limit and constant voltage discharging was performed with 2.5V as the lower limit. The charge and discharge were carried out at a rate of 0.1C, and a

[0422] rest time of 10 minutes was provided after charging. The charge and discharge were performed for 2 cycles. Figure 33(A) shows the charge-discharge curve of sample E1, and Figure 33(B) shows the charge-discharge curve of sample E2. In Figure 33

[0423] (A) and (B), the horizontal axis represents the capacity (mAh / g), and the vertical axis represents the voltage (V). As shown in Figures 33(A) and (B), it can be seen that in samples E1 and E2, the first and second charge discharges were performed normally, and good charge-discharge characteristics were obtained. Also, from the results of Figure 33(B), even when heat treatment was performed, the decrease in capacity was small, and normal charge-discharge characteristics were obtained, indicating high heat resistance.

[0424] 50 Film 51 Film 52 Film 53 Embossing Roll 54 Roll 55 Embossing Roll 56 Embossing Roll 57 Embossing Roll 58 Embossing Roll 60 Travel Direction 101 Positive Electrode Active Material Layer 102 Active Material Layer 105 Electrolyte 115 Sealing Layer 118 Joint 119 Inlet 200 Secondary battery 203 Separator 203a Region 203b Region 207 Outer package 211 Positive electrode 211a Positive electrode 215 Negative electrode 215a Negative electrode 220 Sealing layer 221 Positive electrode lead 225 Negative electrode lead 230 Electrode assembly 231 Electrode assembly 250 Secondary battery 281 Tab region 282 Tab region 500 Power storage device 501 Positive electrode current collector 502 Positive electrode active material layer 503 Positive electrode 504 Negative electrode current collector 505 Negative electrode active material layer 506 Negative electrode 507 Separator 508 Electrolyte 509 Outer package 510 Positive electrode lead 511 Negative electrode lead 512 Joint 513 Bend 514 Joint 518 Joint 529 Outer package 700 Portable information terminal 701 Housing 702 Display panel 703 Fastener 705A Band 705B Band 711 Operation button 712 Operation button 730 Portable information terminal 731 Housing 732 Leakage detection circuit 733 Power supply 734 Ammeter 735A Band 736 Electrolyte 739 Functional circuit 750 Energy storage device 751 Positive electrode lead 752 Negative electrode lead 753 Outer package 760 Energy storage device 761 Terminal 762 Terminal 771 Wiring 772 Wiring 900 Region 901 Region 911 Graphite layer 912 Coating layer 7100 Portable display device 7101 Housing 7102 Display unit 7103 Operation button 7104 Energy storage device 7200 Portable information terminal 7201 Housing 7202 Display unit 7203 Band 7204 Buckle 7205 Operation button 7206 Input / output terminal 7207 Icon 7250 Activity meter 7251 Housing 7300 Display device 7304 Display unit 7350 Display device 7351 Lens 7351A Image 7351B Image 7352 Frame 7355 Tip 7360 Energy storage device 7361 Positive electrode lead 7362 Negative electrode lead 7400 Mobile phone 7401 Housing 7402 Display unit 7403 Operation button 7404 External connection port 7405 Speaker 7406 Microphone 7407 Power storage device 8000 Display device 8001 Housing 8002 Display unit 8003 Speaker unit 8004 Power storage device 8021 Charging device 8022 Cable 8024 Power storage device 8100 Lighting device 8101 Housing 8102 Light source 8103 Power storage device 8104 Ceiling 8105 Side wall 8106 Floor 8107 Window 8200 Indoor unit 8201 Housing 8202 Air outlet 8203 Power storage device 8204 Outdoor unit 8300 Electric refrigerator-freezer 8301 Housing 8302 Door for refrigerator compartment 8303 Door for freezer compartment 8304 Power storage device 8400 Automobile 8401 Headlight 8500 Automobile 9600 Tablet terminal 9625 Switch 9626 Switch 9627 Power switch 9628 Operation switch 9629 Fastener 9630 Housing 9631 Display unit 9631a Display unit 9631b Display unit 9632a Area 9632b Area 9633 Solar cell 9634 Charge-discharge control circuit 9635 Energy storage element 9636 DCDC Converter 9637 Converter 9638 Operation Key 9639 Button 9640 Movable Part

Claims

1. A step of manufacturing a power storage device having a positive electrode, a negative electrode, an exterior body covering the positive electrode and the negative electrode, and an electrolytic solution in a region covered by the exterior body; A step of setting the power storage device in a mold; A step of pouring a rubber material into the mold after setting the power storage device; A step of heating the rubber material at a temperature of 110°C or higher and 190°C or lower in the mold to cure the rubber material, and The electrolytic solution contains propylene carbonate, ethylene carbonate, and LiBETA (lithium bispentafluoroethanesulfonylamide). A method for manufacturing an electronic device.

2. In Claim 1, The negative electrode has a negative electrode active material layer and a negative electrode current collector, and The negative electrode active material layer contains graphite. A method for manufacturing an electronic device.

3. In Claim 2, The negative electrode active material layer contains spherical natural graphite, The spherical natural graphite has a first region and a second region, The first region covers the second region, and The first region has lower crystallinity than the second region. A method for manufacturing an electronic device.

Images