power storage device

Abstract

The present application provides a power storage device that can achieve high voltage, compactness, and easy manufacturing. In the power storage device (1), a winding structure (20) includes: an intermediate electrode body (21) in which a first extension portion (21b) and a second extension portion (21c) that extend from both sides of a middle portion (21a) toward the same direction around the middle portion are wound around the middle portion (21a) as a center; a first electrode body (22) that is electrically connected to a first external terminal (6) and extends from a vicinity of the middle portion toward an outer peripheral side; a second electrode body (23) that is electrically connected to a second external terminal (7) and extends from a vicinity of the middle portion toward the outer peripheral side; a first separator (24) that is disposed between the intermediate electrode body and the first electrode body; and a second separator (25) that is disposed between the intermediate electrode body and the second electrode body.

Description

Technical Field

[0001] This invention relates to energy storage devices, and more particularly to internal electrode structures suitable for energy storage devices that function as energy storage components such as double-layer capacitors, electrolytic capacitors, and other various types of capacitors (capacitor-type energy storage devices). Background Technology

[0002] In recent years, the demand for high-voltage products in the field of double-layer capacitors or electrolytic capacitors has been increasing. As high-voltage products, modular products are known, which are formed by connecting multiple units (energy storage elements) in series (e.g., multiple elements connected in series via a substrate, four-terminal type with multiple elements grouped together and the terminals of each element directly protruding, internal connection type with multiple elements internally connected, etc.). However, these modular products have the following problems: more components, more complicated manufacturing process, increased processing costs, lower profit margins, larger size, etc.

[0003] On the other hand, as high-voltage products composed of a single unit structure, the following products disclosed in Patent Document 1 and Patent Document 2 are known. Patent Document 1 describes a double-layer capacitor in which multiple cylindrical conductors are arranged concentrically in the radial direction through a separator (see [reference]). Figure 4 Furthermore, the high-voltage supercapacitor disclosed in Patent Document 2 has a bipolar element comprising three or four electrodes including an intermediate electrode not connected to external terminals, and these electrodes are wound together with three or four separators in between (see [reference]). Figures 1 to 3 B).

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Utility Model No. 59-101433

[0007] Patent Document 2: Japanese Patent Publication No. 2010-524200 Summary of the Invention

[0008] However, in the energy storage device described in the aforementioned existing patent document 1, when multiple energy storage functional units are connected in series within a single unit structure, it is necessary to arrange the multiple cylindrical energy storage functional units in a concentric circle, which results in problems such as complex structure, difficulty in manufacturing, and an increase in the number of components constituting each part.

[0009] On the other hand, in the energy storage device described in the existing Patent Document 2, since three or four or more electrode bodies containing the intermediate electrode are wound with the same number of diaphragms, the device described in Patent Document 1 also suffers from the same problem as the device: the internal electrode structure lacks symmetry, and the number of layers of the wound structure increases, thus making the size easy to increase.

[0010] Therefore, the present invention will solve the above problems, and its objective is to realize an energy storage device that can achieve both high voltage and compactness and ease of manufacture.

[0011] To address the aforementioned problems, the energy storage device of the present invention includes a wound structure and a first external terminal and a second external terminal connected to the wound structure. The wound structure comprises: a strip-shaped intermediate electrode body, wherein a first extension portion and a second extension portion extending to both sides of the intermediate portion about a central portion in the extending direction are wound around the intermediate portion in the same direction; a first electrode body conductively connected to the first external terminal and disposed between the first extension portion located on the inner periphery and the second extension portion located on the outer periphery, extending from near the intermediate portion to the outer periphery; a second electrode body conductively connected to the second external terminal and disposed between the second extension portion located on the inner periphery and the first extension portion located on the outer periphery, extending from near the intermediate portion to the outer periphery; a first diaphragm disposed between the intermediate electrode body and the first electrode body; and a second diaphragm disposed between the intermediate electrode body and the second electrode body.

[0012] According to this energy storage device, a first extension portion and a second extension portion on both sides of the middle portion of the strip-shaped intermediate electrode body are wound in the same direction. A first electrode body is disposed in one of a pair of radial gaps between the first extension portion and the second extension portion, separated by a first diaphragm, and a second electrode body is disposed in the other of the radial gaps, separated by a second diaphragm. Furthermore, by providing a first external terminal electrically connected to the first electrode body and a second external terminal electrically connected to the second electrode body, two energy storage functional units are connected in series between the first external terminal and the second external terminal, separated by the intermediate electrode body. In this way, since the first energy storage unit, composed of the intermediate electrode and the first electrode, and the second energy storage unit, composed of the intermediate electrode and the second electrode, are respectively arranged in a spiral shape on both sides centered on the middle part, at least two energy storage units can be connected in series to achieve high voltage. Furthermore, the first energy storage unit and the second energy storage unit are not arranged in a radial relationship from the perspective of the wound structure, with one side arranged on the inside and the other on the outside. Instead, they are arranged side by side along the first extension portion and the second extension portion wound in the same direction on both sides of the middle part. Therefore, the internal electrode structure is simple, and it can be manufactured by using the laminate of the wound electrode and the diaphragm, which is easy to manufacture and has a small number of parts. Moreover, compared with the existing method of simply winding three or more electrode bodies with three or more diaphragms in between, radial compactness can be achieved.

[0013] In this invention, it is preferable that the outer edge (side edge) of the intermediate electrode body protrudes further outward in the axial direction of the winding structure than the first and second electrodes of the winding structure. This allows radial electrical leakage beyond the axial direction of the winding structure to be suppressed by the outer edge (side edge) in the width direction of the intermediate electrode body, thereby improving the insulation performance of the device. More preferably, both outer edges (side edges) in the width direction of the intermediate electrode body protrude further outward in the axial direction than the first and second electrodes of the winding structure. In these cases, it is preferable that the winding structure is disposed within a receiving space, with the outer edge (side edge) of the intermediate electrode body abutting against the boundary of the receiving space of the winding structure located outward in the axial direction. This further reduces electrical leakage in the axial direction of the outer periphery within the receiving space, thereby further improving insulation performance. Here, it is preferable that the outer edge of the intermediate electrode body has insulating properties.

[0014] Furthermore, it is preferable that the outer edge (end edge) of the intermediate electrode is positioned radially outward from the winding structure compared to the first and second electrodes in the winding structure. This reduces circumferential electrical leakage beyond the radial outer edge (periphery) of the winding structure by using the outer edge (end edge) in the extending direction of the intermediate electrode, thereby improving insulation performance. More preferably, the outer edges (end edges) on both sides of the intermediate electrode in the extending direction are positioned radially outward compared to the first and second electrodes in the winding structure. In these cases, it is preferable that the winding structure is disposed within a receiving space, with the outer edge (end edge) of the intermediate electrode abutting against the radially outward boundary of the receiving space of the winding structure. This further reduces electrical leakage in the radially outer periphery within the receiving space, thereby further improving insulation performance. Here, it is preferable that the outer edge of the intermediate electrode is insulating.

[0015] Furthermore, it is preferable that the electrolyte is introduced into the wound structure, and at least the portion of the intermediate electrode body sandwiched between the first and second diaphragms prevents the passage of the electrolyte and its ions. Moreover, when introducing the electrolyte into the wound structure, it is preferable that the outer edge (side edge or end edge) of the intermediate electrode body is a portion that is more difficult to retain the electrolyte or its ions, or a portion that is more difficult to allow the electrolyte or its ions to pass through, compared to the main body of the intermediate electrode body. This further improves the separability of the electrolyte in the axial direction or radially outward of the wound structure, thereby further improving insulation performance. More preferably, the outer edge (side edge or end edge) is a portion that prevents the passage of the electrolyte or its ions. This allows for a more reliable reduction of leakage current caused by the electrolyte, thereby further improving the insulation performance of the device.

[0016] In this invention, it is preferable that the first extension portion and the second extension portion, as well as the first electrode body and the second electrode body, are formed in a rotationally symmetrical manner about the intermediate portion. This improves durability and performance stability because it substantially ensures the electrical symmetry between the pair of energy storage functional units connected in series between the intermediate electrode body and the first and second electrode bodies. In this case, it is also preferable that the first diaphragm and the second diaphragm are formed in a rotationally symmetrical manner about the intermediate portion.

[0017] In this invention, the intermediate electrode body is preferably composed of multiple electrode body layers arranged with a separator layer between them. Therefore, since more than one energy storage unit is formed between the multiple electrode body layers, further high voltage can be achieved.

[0018] In this invention, it is preferable that the wound structure has a structure in which the outer peripheries of the first electrode body and the second electrode body are covered from the radial outer periphery by the outer periphery of the intermediate electrode body. This suppresses electrical leakage beyond the intermediate electrode body between the first and second electrode bodies, thereby further improving insulation performance. In this case, it is preferable that the outer periphery of the first and second diaphragms, located between the intermediate electrode body and the first and second electrode bodies, exists within a larger angular range relative to the radial outer periphery of the first and second electrode bodies.

[0019] In this invention, preferably, the first diaphragm is disposed in one of a pair of radially inner and outer gaps between the intermediate electrode body and the first electrode body, respectively disposed radially inner and outer; and a first dividing member with electrolyte blocking properties and electrical insulation is disposed in the other gap. Conversely, the second diaphragm is disposed in one of a pair of radially inner and outer gaps between the intermediate electrode body and the second electrode body, respectively disposed radially inner and outer; and a second dividing member with electrolyte blocking properties and electrical insulation is disposed in the other gap. In this case, preferably, the first dividing member is disposed in the gap on one side of the radially inner and outer gap, and the second dividing member is also disposed in the gap on the same side as the first dividing member.

[0020] In this case, it is preferable that the dividing member is made of a synthetic resin. Examples of synthetic resins include polyphenylene sulfide (PPS), polyimide (PI), aramid (all-aromatic polyamide), polyetheretherketone (PEEK), polyethylene terephthalate (PET), polytetrafluoroethylene (PTFE), polypropylene (PP), and polyethylene (PE). Furthermore, as a preferred embodiment of the above-described wound structure, it is preferable that the dividing member is sheet-shaped. Moreover, when an electrolyte is introduced into the wound structure, it is preferable that the dividing member prevents the electrolyte and its ions from passing through. In particular, it is preferable that the dividing member possesses both impermeability and non-retention properties for the electrolyte and its ions. For example, it is preferable that it is made of a sheet material without voids. This allows for a more reliable reduction of leakage current caused by the electrolyte, thereby further improving the insulation performance of the device. From these perspectives, preferred synthetic resin sheets include fluoropolymer sheets made of polytetrafluoroethylene (PTFE), perfluoroalkoxyalkylene (PFA), perfluoroethylene-propylene copolymer (FEP), polyvinylidene fluoride (PVDF), ethylene-tetrafluoroethylene copolymer (ETFE), and polychlorotrifluoroethylene (PCTFE). Furthermore, when the electrolyte is liquid, it is preferable that the segmented component has a surface with a contact angle of 80 degrees or more with the electrolyte. Particularly preferred is a contact angle exceeding 90 degrees (obtuse angle).

[0021] In this invention, it is preferable that the outer edges of the first and second segmented components protrude further along the axial direction of the winding structure than either the intermediate electrode body or at least one of the first or second electrode body. In this case, when the winding structure is disposed within a storage space, it is preferable that the outer edges of the first and second segmented components abut (more preferably be fixed) against the boundary of the storage space located outside the axial direction.

[0022] In this invention, preferably, the outer edges of the first dividing member and the second dividing member are respectively disposed at a position further radially outward from the winding structure than at least one of the intermediate electrode body and the first electrode body or the second electrode body. In this case, when the winding structure is disposed within a storage space, preferably, the outer edges of the first dividing member and the second dividing member abut (more preferably, are fixed) against the radially outward boundary of the storage space.

[0023] In this invention, it is preferable that the inner edge of the first dividing member is configured to extend further inward to the inner circumference than the inner edge of the first electrode body, and that the inner edge of the second dividing member is configured to extend further inward to the inner circumference than the inner edge of the second electrode body. In particular, it is preferable that the inner edges of the first dividing member and the second dividing member abut (more preferably, be fixed) against the inner circumference of the middle portion, etc., of the intermediate electrode body.

[0024] (Invention Effects)

[0025] According to the present invention, it is possible to provide an energy storage device that can achieve both high voltage and compactness and ease of manufacture. Attached Figure Description

[0026] Figure 1 These are perspective views (a) schematically showing the appearance of the first embodiment of the energy storage device and perspective views (b) schematically showing the internal winding structure.

[0027] Figure 2 This is a cross-sectional view schematically showing the cross-sectional structure of the winding structure of the first embodiment.

[0028] Figure 3 This is an explanatory diagram schematically showing the overall configuration of the winding structure of the first embodiment before winding.

[0029] Figure 4 It is an enlarged cross-sectional view schematically showing the cross-sectional structure of each component of the winding structure of the first embodiment.

[0030] Figure 5This is an enlarged cross-sectional view schematically showing the connection structure of the connector component for connecting external terminals in the first or second electrode body of the first embodiment.

[0031] Figure 6 These are explanatory diagrams (a) to (d) schematically illustrating the winding process used to form the winding structure of the first embodiment.

[0032] Figure 7 These are an explanatory cross-sectional view (a) schematically showing the radial cross-sectional structure of the storage structure inside the container of the first embodiment of the winding structure, and an explanatory cross-sectional view (b) schematically showing the circumferential cross-sectional structure.

[0033] Figure 8 These are a top view (a) schematically showing the unfolded state of the intermediate electrode body of the second embodiment and a perspective view (b) schematically showing the winding structure.

[0034] Figure 9 These are an explanatory diagram (a) schematically showing the radial cross-sectional structure of the storage structure inside the container of the winding structure of the second embodiment, and an explanatory cross-sectional view (b) schematically showing the circumferential cross-sectional structure.

[0035] Figure 10 This is a schematic cross-sectional view illustrating the cross-sectional structure of the winding structure according to the second embodiment.

[0036] Figure 11 This is a schematic cross-sectional view illustrating the cross-sectional structure of the winding structure according to the third embodiment.

[0037] Figure 12 This is a schematic cross-sectional view illustrating the cross-sectional structure of the winding structure according to the fourth embodiment.

[0038] Figure 13 This is a schematic cross-sectional view illustrating the cross-sectional structure of the winding structure according to the fifth embodiment.

[0039] Figure 14 This is a schematic cross-sectional view illustrating the cross-sectional structure of the winding structure according to the sixth embodiment.

[0040] Figure 15 This is a schematic cross-sectional view illustrating the cross-sectional structure of the winding structure according to the seventh embodiment.

[0041] Figure 16 These are schematic cross-sectional views (a) showing the cross-sectional structure of the winding structure according to the eighth embodiment, and explanatory diagrams (b) showing the overall configuration before winding.

[0042] Figure 17These are schematic cross-sectional views (a) showing the cross-sectional structure of the winding structure according to the ninth embodiment, and explanatory diagrams (b) showing the overall configuration before winding.

[0043] (Symbol Explanation)

[0044] 1…Electrical storage device (double-layer capacitor), 2…Wound capacitor element, 3…Container (shell), 4…Sealing component, 5…Electrolyte, 6…First external terminal, 7…Second external terminal, 20, 50…Wound structure, 21, 21′, 31, 41, 51…Intermediate electrode body, 21a, 31a, 41a, 51a…Intermediate portion, 21b, 31b, 41b, 51b…First extension portion, 21c, 31c, 41c, 51c…Second extension portion, 21d…Outer edge, 21e…End edge, 21f…Side edge, 31g…Isolation Film layer, 31h, 31i…electrode body layer, 41j, 41k…outer peripheral portion, 22, 52…first electrode body, 23, 53…second electrode body, 24, 54, 54′…first diaphragm, 25, 55, 55′…second diaphragm, 26…holding component, 27, 28…adhesive layer, 211, 221, 231, 511, 521, 531…current collector, 212, 213, 222, 223, 232, 233, 512, 513, 522, 532…polarized electrode layer, 56, 57, 56′, 57′…segmentation component Detailed Implementation

[0045] Next, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the embodiments of the present invention, a double-layer capacitor will be used as an example of an energy storage device. First, referring to... Figure 1 The overall configuration of the first embodiment of the energy storage device involved in this invention will be described.

[0046] <First Implementation>

[0047] Figure 1These are perspective views (a) of the energy storage device 1 according to this embodiment and (b) schematically showing the wound capacitor element 2 housed inside the energy storage device 1. The energy storage device 1 includes a wound capacitor element 2, a bottomed (bottomed cylindrical) container 3 housing the wound capacitor element 2, and a sealing member 4 for the container 3. The wound capacitor element 2 is formed by introducing (impregnating) an electrolyte 5 into a wound structure 20 having a structure formed of wound strip (sheet). The container 3 can be made of a metal such as aluminum. The sealing member 4 has a through hole for inserting a first external terminal 6 and a second external terminal 7 of the wound capacitor element 2. The sealing member 4 seals the wound capacitor element 2 housed inside the container 3 and leads the first external terminal 6 and the second external terminal 7 to the outside through the through hole. The sealing member 4 can be made of various synthetic rubbers or elastomers.

[0048] Figure 2 This is a schematic cross-sectional view showing the cross-section of the aforementioned wound structure 20. The wound structure 20 has a strip-shaped intermediate electrode body 21, which has a first extension portion 21b and a second extension portion 21c on both sides of the intermediate portion 21a in the extending direction. Moreover, in the example shown, both the first extension portion 21b and the second extension portion 21c are wound in a counterclockwise direction with the intermediate portion 21a as the center. On both the front and back sides of the intermediate electrode body 21, strip-shaped first diaphragms 24 and second diaphragms 25 are respectively arranged to cover the front and back sides of the intermediate electrode body 21.

[0049] Furthermore, viewed from the center of the aforementioned intermediate portion 21a, a strip-shaped first electrode body 22 is disposed in the gap between the first extension portion 21b on the inner peripheral side and the second extension portion 21c on the outer peripheral side. At this time, the aforementioned first diaphragm 24 is disposed between the first extension portion 21b and the first electrode body 22. Additionally, the aforementioned first diaphragm 24 is also disposed between the second extension portion 21c and the first electrode body 22. On the other hand, a strip-shaped second electrode body 23 is disposed between the second extension portion 21c on the inner peripheral side and the first extension portion 21b on the outer peripheral side. At this time, the aforementioned second diaphragm 25 is disposed between the second extension portion 21c and the second electrode body 23. Additionally, the aforementioned second diaphragm 25 is also disposed between the first extension portion 21b and the second electrode body 23. Both the first diaphragm 24 and the second diaphragm 25 are integrally formed on the surface and back of the intermediate electrode body 21, respectively. That is, both the first diaphragm 24 and the second diaphragm 25 are continuous at the portion adjacent to the aforementioned intermediate portion 21a, and the portion along the first extension portion 21b and the portion along the second extension portion 21c are integrally formed. However, it can also be configured in the same way as other embodiments described later: at least one of the first diaphragm 24 and the second diaphragm 25 is separated at the portion adjacent to the aforementioned intermediate portion 21a, and the portion along the first extension portion 21b and the portion along the second extension portion 21c are separate.

[0050] In the aforementioned wound structure 20, the intermediate electrode 21, the first diaphragm 24, the first electrode 22, the second diaphragm 25, and the second electrode 23 are wound in a mutually laminated manner as shown in the example figure, and are finally held and fixed in the wound state by the outermost retaining member (e.g., anti-winding tape) 26. However, it should be noted that... Figure 2 Ultimately, this diagram is merely illustrative, depicting a form different from the actual winding state. For example, the reproducibility of the tightness between layers is ignored, and the number of windings is significantly reduced in most cases. Furthermore, the outermost circle in the diagram represents the boundary of the storage space of the winding structure 20, corresponding to the container 3 or holding member 26, i.e., the boundary of the space where the electrolyte 5 can exist in this embodiment. That is, the circle in the diagram schematically shows the division of space for the storage function, shape maintenance function, insulation function, etc., of the winding structure 20 required according to the state of the winding structure 20 with the above structure. Therefore, its shape (circle) itself is meaningless and not limited. Furthermore, the pair of circles shown by the double-dotted lines in the diagram should respectively correspond to... Figure 1 The approximate location of the junction (formation site of the connector component) where the first external terminal 6 and the second external terminal 7 are electrically connected is shown. Furthermore, it is not limited to... Figure 2The accompanying drawings referenced in this specification should be understood as schematic diagrams or partially enlarged illustrations, and the shapes depicted in the drawings do not necessarily represent the actual configuration of the embodiment. Here, the aforementioned retaining member 26 is not necessarily formed by a single component and may be divided into multiple parts. Furthermore, the aforementioned retaining member 26 is sometimes formed on the outer periphery of the winding structure 20 within a range less than one revolution around the axis, and sometimes within a range more than one revolution. Moreover, the same applies to the other components constituting the winding structure 20, as it is not necessarily formed by a single component.

[0051] Figure 3 This diagram schematically illustrates the unfolded configuration of the intermediate electrode body 21, the first diaphragm 24, the first electrode 22, the second diaphragm 25, and the second electrode 23. As can be seen from this unfolded configuration, the first diaphragm 24 is positioned between the intermediate electrode body 21 and the first electrode body 22. Furthermore, the second diaphragm 25 is positioned between the intermediate electrode body 21 and the second electrode body 23.

[0052] Figure 4 This is a schematic cross-sectional view showing the more detailed structures of the intermediate electrode body 21, the first diaphragm 24, the first electrode 22, the second diaphragm 25, and the second electrode 23. In the intermediate electrode body 21, a current collector 211 made of metal foil or the like is formed, and polarized electrode layers 212 and 213 made of carbon-containing porous materials or the like are formed on both sides of the current collector 211. Similarly, in the first electrode body 22, a current collector 221 made of metal foil or the like is formed, and polarized electrode layers 222 and 223 made of carbon-containing porous materials or the like are formed on both sides of the current collector 221. Furthermore, in the second electrode body 23, a current collector 231 made of metal foil or the like is formed, and polarized electrode layers 232 and 233 made of carbon-containing porous materials or the like are formed on both sides of the current collector 231.

[0053] As the current collectors 211, 221, and 231, aluminum foil with a thickness of 20 μm to 50 μm can be used, for example. Furthermore, as the polarization electrode layers 212, 213, 222, 223, 232, and 233, a carbon-containing microparticle slurry can be prepared by mixing activated carbon powder and carbon black with a binder, and then coating the slurry to both the front and back surfaces of the current collectors 211, 221, and 231 with a thickness of 10 μm to 200 μm and allowing it to dry. Alternatively, the polarization electrode layers can be formed on only one side of the current collectors 211, 221, and 231, rather than both sides.

[0054] For example, cellulose nonwoven fabrics with a thickness of 20 μm to 100 μm can be used as the first diaphragm 24 and the second diaphragm 25. In addition to cellulose nonwoven fabrics, diaphragms made of nonwoven fabrics of polyimide (PI), aramid (all-aromatic polyamide), polyetheretherketone (PEEK), polyethylene terephthalate (PET), polytetrafluoroethylene (PTFE), polypropylene (PP), and polyethylene (PE) can also be used. Furthermore, the materials constituting the diaphragms are not limited to the aforementioned nonwoven fabrics; for example, they can also be made of paper made solely from cellulose pulp.

[0055] As the aforementioned retaining component (anti-winding tape) 26, an adhesive tape made of resin such as polypropylene (PP), polyphenylene sulfide (PPS), or polyimide (PI) with excellent solvent resistance, heat resistance, and insulation properties can be used.

[0056] As the electrolyte 5 introduced into the winding structure 20, the type of electrolyte can be selected according to the type of energy storage device. For example, in the case of the double-layer capacitor of this embodiment, tetraethylammonium salt can be used for the cation, and boron tetrafluoride, bis(trifluoromethanesulfonyl)imide, etc. can be used for the anion. As the electrolyte in this case, liquid or gel electrolytes can be used. In addition, as other capacitor-type energy storage devices, such as in the case of constituting an electrolytic capacitor, various electrolytes using boric acid, adipic acid, maleic acid, benzoic acid, phthalic acid, salicylic acid, ammonia, triethylamine, tetramethylammonium hydroxide, etc., can be used. In addition, as the electrolyte 5, solid electrolytes such as manganese dioxide or organic semiconductors, or conductive solids such as conductive polymers and others (e.g., conductive inorganic materials) can also be used.

[0057] Furthermore, by placing a non-flowing ion conductor between the intermediate electrode and the first and second electrodes, contact and short circuits between the electrodes can be prevented. Examples of non-flowing ion conductors include sheet-like ion conductors formed by mixing a solid electrolyte with a supporting material such as a resin, or gel-like electrolytes. This non-flowing ion conductor also functions as a membrane that ensures ion conductivity and prevents contact and short circuits between the electrodes.

[0058] Figure 5 Examples of conductive connections in the first electrode body 22 relative to the first external terminal 6 and in the second electrode body 23 relative to the second external terminal 7 are schematically shown. It should be noted that... Figure 5An example of a first electrode body 22 and a first external terminal 6 is shown, but a second electrode body 23 and a second external terminal 7 can also be constructed in the same way. As shown, a region 221a is formed on a portion of the first electrode body 22. This region 221a is a region where a portion of at least one of the polarization electrode layers 222 and 223 (222 in the example) is removed, exposing a portion of the current collector 221. This region 221a engages with a connector member 214, which is electrically connected to the current collector 221. The position of the connector member 214 is predetermined along with the formation position of the aforementioned region 221a, so that it is positioned at a predetermined location when the aforementioned wound structure 20 is formed.

[0059] In this case, a protective film 215 can be disposed in the gap between the first diaphragm 24 and the intermediate electrode body 21, which are opposite to the aforementioned connector component 214. This protective film 215 has the property of preventing the passage of electrolyte and ions and has insulating properties. For example, in the illustrated example, the protective film 215 can be attached to the surface of the first diaphragm 24 on the side of the intermediate electrode body 21. In this way, the diaphragm is less prone to deterioration, and the characteristics of the energy storage device are less likely to deteriorate. As the protective film 215, for example, polyphenylene sulfide (PPS) with a thickness of 1μm to 200μm, preferably 5μm to 50μm, can be used.

[0060] Figure 6 These are schematic process diagrams (a) to (d) illustrating the steps involved in forming the aforementioned wound structure 20. First, as... Figure 6 As shown in (a), the intermediate electrode body 21 and the first diaphragm 24 and the second diaphragm 25 disposed on its front and back surfaces are arranged between the core member 10 (a pair of cores 10a and 10b), which is configured to be separable. At this time, the intermediate electrode body 21, the first diaphragm 24, and the second diaphragm 25 are held in a releasable manner by left and right strip feeding systems (not shown) including a feeding mechanism with a supply spool having a rotational resistance application mechanism, a tension roller, a guide roller, etc., hereinafter the same). Then, as... Figure 6 As shown in (b), the middle portion 21a of the intermediate electrode body 21 and the middle portions of the first diaphragm 24 and the second diaphragm 25 are sandwiched between a pair of winding cores 10a and 10b, and as shown in (b). Figure 6 As shown in (c), the core component 10 is rotated, thereby as shown in (c) Figure 6 As shown in (d), the intermediate electrode 21, the first diaphragm 24, and the second diaphragm 25 can be wound around the intermediate portion 21a held by the core member 10. At this time, the first electrode 22 is wound into the first diaphragm 24, and the second electrode 23 is wound into the second diaphragm 25. As the core member 10 rotates, each electrode is released through a left-right tape supply system (not shown). Finally, a retaining member (anti-winding tape) 26 is attached (adheded) to the outermost layer to maintain the aforementioned winding state.

[0061] When the wound structure 20 is formed as described above, the first external terminal 6 and the second external terminal 7 are inserted into the through holes of the sealing member 4 in a state of conductive connection by engaging with the corresponding connector member 214. Furthermore, the wound structure 20 is placed in the container 3 in a state of being impregnated with electrolyte, for example, as electrolyte 5, and finally the opening of the container 3 is sealed by the sealing member 4.

[0062] Figure 7 These are schematic cross-sectional views (a) and (b) illustrating the overall configuration of the energy storage device 1 of this embodiment as described above. Figure 7 (a) schematically shows the radial relative positional relationship of the wound structure 20 (internal electrode structure) of the energy storage device 1. Figure 7 Image (b) schematically illustrates the relative positional relationship of the wound structure 20 (internal electrode structure) of the energy storage device 1 about its axis (circumferential direction). Figure 7 As shown, inside the energy storage device 1 (unit structure), a first energy storage unit and a second energy storage unit are provided in the electrolyte 5 introduction (immersion) area. The first energy storage unit consists of a portion of an intermediate electrode 21 and a first electrode 22 facing each other across a first separator 24. The second energy storage unit consists of a portion of an intermediate electrode 21 and a second electrode 23 facing each other across a second separator 25. Since these two energy storage units are connected in series between the first external terminal 6 and the second external terminal 7, nearly twice the voltage can be obtained compared to a unit structure with only a single energy storage unit. Furthermore, this embodiment uses the double layer formed at the interface between each electrode 21, 22, 23 and the electrolyte 5 as a dielectric to store charge in a double-layer capacitor; however, the aforementioned series structure is also the same in electrolytic capacitors and other capacitors.

[0063] In the first embodiment described above, such as Figure 2As shown, the first extension portion 21b and the second extension portion 21c on both sides of the middle portion 21a of the strip-shaped intermediate electrode body 21 are wound in the same direction. A first electrode body 22 is disposed in one of the two radial gaps between the first extension portion 21b and the second extension portion 21c, separated by a first diaphragm 24, and a second electrode body 23 is disposed in the other of the two radial gaps, separated by a second diaphragm 25. Furthermore, by providing a first external terminal 6 electrically connected to the first electrode body 22 and a second external terminal 7 electrically connected to the second electrode body 23, two energy storage functional units are connected in series between the first external terminal 6 and the second external terminal 7, separated by the intermediate electrode body 21. Since the first energy storage functional unit formed by the intermediate electrode body 21 and the first electrode body 22 and the second energy storage functional unit formed by the intermediate electrode body 21 and the second electrode body 23 are not radially overlapping, from a radial perspective, the first energy storage functional unit and the second energy storage functional unit are not arranged with one side on the inside and the other on the outside. That is, in the wound structure 20 of this embodiment, by alternately or side by side arranging the first electrode body 22 and the second electrode body 23 within the angular range surrounding the intermediate portion 21a, the deviation of radial structural symmetry can be reduced. In addition, since the first electrode body 22 and the second electrode body 23 are respectively constructed by winding the first extension portion 21b and the second extension portion 21c in the same direction on both sides of the intermediate portion 21a, although the winding method is different, the prior art can be developed, and it can be manufactured by winding the laminate of the electrode body and the diaphragm, thus simplifying the manufacturing process and reducing the number of parts.

[0064] In this embodiment, such as Figure 2 As shown, the first extension portion 21b and the second extension portion 21c, as well as the first electrode body 22 and the second electrode body 23, are preferably formed in a rotationally symmetrical manner with respect to the middle portion 21a of the intermediate electrode body 21. Therefore, the first and second energy storage functional units have substantially the same structure, thus substantially ensuring the electrical symmetry between the pair of energy storage functional units connected in series between the intermediate electrode body 21 and the first and second electrode bodies 22 and 23. Furthermore, when configured as described above, deviations in applied voltage, etc., can be reduced, thereby improving the durability and characteristic stability of the energy storage device.

[0065] More specifically, in Patent Documents 1 and 2, structural issues such as radial arrangement or size differences lead to significant characteristic differences among multiple energy storage units, potentially causing problems with durability and characteristic stability. For example, when the intermediate electrode body 21 is formed rotationally symmetrically around its central portion 21a, large differences in leakage current between the energy storage units result in increased voltage deviation due to self-discharge. Consequently, in energy storage units with low leakage current, the voltage increases with the duration of voltage application, eventually reaching the solvent decomposition voltage, posing a risk of gas generation and increased resistance. Furthermore, when multiple energy storage units are sealed within a container, short circuits between the electrodes caused by the electrolyte can sometimes lead to increased leakage current. This increased leakage current is also a major cause of further deterioration in durability and characteristic stability.

[0066] In contrast, the energy storage device according to this embodiment, since the first energy storage unit composed of the intermediate electrode 21 and the first electrode 22, and the second energy storage unit composed of the intermediate electrode 21 and the second electrode 23, are arranged side-by-side in a rotating manner on both sides centered on the intermediate portion 21a, it is easy to achieve uniformity and balance of the characteristics of the first and second energy storage units. In particular, by configuring the intermediate electrode 21, the first electrode 22, and the second electrode 23 in a rotationally symmetrical manner centered on the intermediate portion 21a as described above, the characteristics of the two units can be balanced. As a result, the voltage is less likely to concentrate on one side, thus greatly improving durability and characteristic stability. In this case, it is even more effective if the first diaphragm 24 and the second diaphragm 25 are also configured in a rotationally symmetrical manner.

[0067] also, Figure 7 The image depicts a situation where the outer periphery of the wound structure 20 is covered by the retaining member 26, and the inner surface of the container 3 is disposed on its outer side, but... Figure 7 The configuration shown is merely illustrative; even if the outer periphery is configured as shown, it is only one example. For instance, a gap may be provided between the container 3 and the electrolyte 5, differing from the illustrated configuration, or an insulating coating may be applied to the inner surface of the container 3. Furthermore, since... Figure 7 This is a schematic diagram, therefore it is related to... Figure 2 The mismatch in cross-sectional structure is illustrated by the absence of a first diaphragm 24 and a second diaphragm 25 or an intermediate electrode body 21 on the radially outer sides of the first electrode body 22 and the second electrode body 23. However, such a peripheral configuration can also be considered as... Figure 2The cross-sectional structure shown corresponds to the configuration in which a first diaphragm 24 is arranged radially outward from the first electrode body 22 and / or a second diaphragm 25 is arranged radially outward from the second electrode body 23. Alternatively, it can be considered as the configuration in which an intermediate electrode body 21 is arranged radially outward from each of the above-mentioned diaphragms 24 and 25.

[0068] <Second Implementation>

[0069] Next, refer to Figures 8 to 10 The energy storage device according to the second embodiment of the present invention will be described. In this second embodiment, the configuration other than the wound capacitor element 2' is the same as that in the first embodiment. Figure 8 The overall structure of the wound structure 20′ shown is as follows: Figure 10 The general cross-sectional structure of the winding structure 20′ shown can also be constructed in the same way as the winding structure 20. Therefore, the same symbols are given to the parts that can be constructed in the same way, and their descriptions are omitted.

[0070] In this second embodiment, such as Figure 8 As shown in (a), the side edge 21f of the outer edge portion 21d of the intermediate electrode body 21′, which is the outer edge portion in the width direction, is configured to protrude further outward in the axial direction of the winding structure 20′ than the first electrode body 22 and the second electrode body 23 (see reference). Figure 9 (a) Here, it is more preferable that the side edge 21f is configured to be located at a position in the same axial direction as the outer edge of the first diaphragm 24 and the second diaphragm 25, or to protrude further outward in the axial direction than the outer edge position. Furthermore, even if the side edge 21f is configured differently from this embodiment, and is located at a position in the same axial direction as the outer edge of the first diaphragm 24 and the second diaphragm 25, or to protrude further outward in the axial direction than the outer edge position, regardless of the relationship between the side edge 21f and the first electrode body 22 and the second electrode body 23, the electrolyte separation can be improved, and thus the leakage current between a pair of energy storage functional units can also be reduced.

[0071] Furthermore, the end edge 21e of the outer edge portion 21d of the intermediate electrode body 21′, which extends in the direction of extension, is configured such that it is located radially outward of the winding structure body 20′ relative to the first electrode body 22 and the second electrode body 23 (see reference). Figure 10Here, it is more preferable that the aforementioned end edge 21e is disposed at a radial position at the same location as the outer edge of the first diaphragm 24 and the second diaphragm 25, or disposed at a position further radially outward than the outer edge position. Furthermore, even if the end edge 21e is configured differently from this embodiment, such that it is disposed at a radial position at the same location as the outer edge of the first diaphragm 24 and the second diaphragm 25, or disposed at a position further radially outward than the outer edge position, regardless of the relationship between the end edge 21e and the first electrode body 22 and the second electrode body 23, the electrolyte separation can be improved, thereby also having the effect of reducing the leakage current between a pair of energy storage functional units.

[0072] Figure 8 The double-dotted line shown in (a) indicates the outer edges of the first electrode body 22 and the second electrode body 23. This outer edge also indicates the reference position for the relative positional relationship between the end edge 21e and the side edge 21f in the outer edge portion 21d of the intermediate electrode body 21' of the winding structure 20'. These points will be explained in more detail later. Furthermore, in the case of the example shown in the figure, the outer edge portion 21d of the intermediate electrode body 21' is formed in a frame shape on the outside of the polarization electrode layers 212 and 213 of the intermediate electrode body 21'. In addition, the end edge 21e and the side edge 21f are formed on both sides in the extension direction and the width direction, respectively.

[0073] In this embodiment, the aforementioned outer edge 21d is formed on the outer side of the main body portion, which is composed of the electrode regions including the current collector 211 and the polarized electrode layers 212, 213. The outer edge 21d is not particularly limited, but it is preferably formed of a portion that, compared to the main body portion constituting the intermediate electrode body 21' (the laminated structure of the current collector 211 and the polarized electrode layers 212, 213), is less likely to retain electrolyte 5 and / or its ions, or less likely to allow electrolyte 5 and / or its ions to pass through. For example, the outer edge 21d can be formed by extending the portion of the aforementioned polarized electrode layers 212, 213 that, compared to the aforementioned polarized electrode layers 212, 213 (which are porous), are less likely to retain electrolyte 5 and / or its ions, or less likely to allow electrolyte 5 and / or its ions to pass through. For example, it can be formed of sheets, films, strips, etc., made of synthetic resin, as described later. Furthermore, the outer edge portion 21d may, for example, be composed of a current collector 211 exposed by peeling off the aforementioned polarized electrode layers 212, 213 that do not easily retain the electrolyte 5 and / or its ions. Moreover, the outer edge portion 21d may have a structure similar to the laminated structure of the current collector 211 and polarized electrode portions 212, 213 of the main body portion, but it may also have a thicker current collector 211 as the core material or a thinner polarized electrode layer 212, 213 compared to the main body portion, resulting in a portion that is less likely to retain the electrolyte 5 and / or its ions, or a portion that is less likely to allow the electrolyte 5 and / or its ions to pass through. These outer edge portions 21d are provided to reduce electrical leakage at the outer periphery of the outer side of the winding structure 20'. In this embodiment, they are particularly provided to improve the separability between the first electrode body 22 side and the second electrode body 23 side relative to the electrolyte 5 or its ions introduced into the winding structure 20'.

[0074] Furthermore, by making the outer edge portion 21d (end edge 21e, side edge 21f) an insulator, the insulator can cover the area around the intermediate electrode body 21', thereby suppressing internal conduction between the first electrode body 22 and the second electrode body 23, improving insulation performance, and further effectively reducing leakage current. As such a specific insulating edge portion 21d, sheets, films, strips, etc., made of polyphenylene sulfide (PPS), polyimide (PI), aramid (all-aromatic polyamide), polyether ether ketone (PEEK), polyethylene terephthalate (PET), polytetrafluoroethylene (PTFE), polypropylene (PP), or polyethylene (PE) can be used. These materials, in addition to their insulating properties, also possess the property of preventing the electrolyte 5 and its ions from passing through, thus further improving the characteristics (insulation performance) of the energy storage device, such as reducing leakage current.

[0075] Figure 9 Therefore, it is consistent with the first embodiment. Figure 7The diagram (a) schematically illustrates the radial relative positional relationship of the internal electrode structure of the energy storage device 1 according to the second embodiment, and the diagram (b) schematically illustrates the relative positional relationship of the electrode structure of the energy storage device around its axis. As can be seen from these diagrams, since the electrolyte 5 can be easily isolated radially from the winding structure 20' by the side edge 21f of the outer edge 21d, the reduction in insulation performance due to the electrolyte 5 can be suppressed. Specifically, as shown, the side edge 21f abuts against the inner surface of the holding member 26 disposed inside the container 3 or its interior, or the sealing member 4 and sealing resin, etc. (the boundary of the storage space of the winding structure 20', i.e., the boundary of the space where the electrolyte 5 may be present in this embodiment). Thus, by abutting against the boundary of the storage space of the winding structure 20' in the axial direction, the storage space is substantially isolated radially from the winding structure 20', thereby further improving the insulation performance.

[0076] In particular, since electrolyte 5 tends to accumulate on the outer side of the axial direction of the wound structure 20′ (especially at the bottom), the side edge 21f is effective in isolating the electrolyte 5. Here, in the intermediate electrode body 21′ of the figure example, the side edge 21f is provided on both sides in the width direction, but it may also be provided on only one side. However, as in the figure example, it is undoubtedly more effective for a pair of side edges 21f on both sides in the width direction to protrude together or to abut together against the aforementioned boundary (the aforementioned inner surface, etc.).

[0077] like Figure 10 As shown, in the wound structure 20', the end edge 21e of the outer edge portion 21d is positioned radially outward of the wound structure 20', compared to the first electrode body 22, the second electrode body 23, the first diaphragm 24, and the second diaphragm 25. Figure 10 As shown, the circumferential separation of the electrolyte 5 in the wound structure 20' can be further improved by the peripheral arrangement of the end edge 21e. In particular, as can be seen from the figure, by having the aforementioned end edge 21e abut against the inner surface of the holding member 26 disposed on the radially outer side (outer peripheral side) of the wound structure 20', or the sealing member 4 and sealing resin, etc. (the boundary of the storage space of the wound structure 20', i.e., the boundary of the space where the electrolyte 5 may be present in this embodiment), the circumferential separation of the electrolyte 5 is further improved. Here, as Figure 8 As shown, the end edges 21e are provided on both sides of the extension direction of the intermediate electrode body 21', but they may also be provided on only one side. However, as in the example shown, it is undoubtedly more effective for the pair of end edges 21e on both sides of the extension direction of the intermediate electrode body 21' to be arranged together on the outer periphery or to abut together against the aforementioned boundary (such as the aforementioned inner surface).

[0078] In this embodiment, the outer edge 21d of the intermediate electrode body 21′, for example... Figure 9 The side edge 21f shown and Figure 10 The end edges 21e shown in the illustration are constructed with a different structure and / or a different material than the main body. However, even when the intermediate electrode body 21 is constructed with a uniform structure and / or a uniform material as in the first embodiment, by using... Figure 2 The double-dotted line indicates that the end edge is located on the radial outer periphery, or Figure 7 The outer edge of the intermediate electrode body 20, indicated by the double-dotted line, protrudes in the axial direction, which can reduce leakage current and improve insulation performance. In this case, as long as the portion of the current collector 211, which is the core material of the intermediate electrode body 20, and which has a high separation effect on the electrolyte 5 reaches the end face of the outer edge 21d (end edge 21e or side edge 21f) and is exposed on the end face of the outer edge 21d, the effect of reducing leakage current can be better obtained. In particular, if the above portion is made relatively thicker than the surface portion such as the polarization electrode layer, the separation with respect to the electrolyte 5 can be improved, and thus it is more effective. Furthermore, it is the same as in this embodiment that the side edge of the intermediate electrode body 20 abuts against the boundary of the storage space in the axial direction, or the end edge abuts against the boundary of the storage space in the radial direction.

[0079] In this embodiment, such as Figure 9 As shown in (a), the side edge 21f of the outer edge 21d of the intermediate electrode body 21′, which is the outer edge in the width direction, is positioned further outward in the axial direction than the first electrode body 22, the second electrode body 23, the first diaphragm 24, and the second diaphragm 25. However, as long as the side edge 21f protrudes further outward in the axial direction than at least one of the first electrode body 22 and the second electrode body 23, the leakage current between the pair of energy storage functional units is reduced, and therefore it is considered to be effective in improving insulation performance. In addition, as long as the side edge 21f protrudes further outward in the axial direction than at least one of the first diaphragm 24 and the second diaphragm 25, the leakage current between the pair of energy storage functional units is reduced, and therefore it is considered to be effective in improving insulation performance.

[0080] In this embodiment, such as Figure 10As shown, the outer edge 21e of the outer edge portion 21d of the intermediate electrode body 21', which extends in the direction of extension, is positioned radially outward of the winding structure 20' compared to the first electrode body 22 and the second electrode body 23. However, as long as the end edge 21e is positioned radially outward of the winding structure 20' compared to at least one of the first electrode body 22 and the second electrode body 23, the separation between the pair of energy storage functional units can be improved, and therefore it is considered to be effective in improving insulation performance. In addition, as long as the end edge 21e is positioned radially outward of the winding structure 20' compared to at least one of the first diaphragm 24 and the second diaphragm 25, the separation between the pair of energy storage functional units can be improved, and therefore it is considered to be effective in improving insulation performance.

[0081] Furthermore, when at least one of the intermediate electrode 21', the first electrode 22, and the second electrode 23 comes into contact with the boundary of the storage space (such as the aforementioned inner surface), it is preferable that the boundary (such as the aforementioned inner surface) is insulating. However, even if the boundary (such as the aforementioned inner surface) is conductive, it is sufficient to avoid any of the following situations: multiple different electrode bodies coming into contact with components constituting the same boundary; the electrolyte in the first electrode 22 and the second energy storage unit coming into contact with components constituting the same boundary; or the second electrode 23 and the electrolyte in the first energy storage unit coming into contact with components constituting the same boundary.

[0082] <Third Implementation Method>

[0083] Next, refer to Figure 11 The energy storage device according to the third embodiment of the present invention will be described. In this embodiment, since the components other than the first diaphragm 24′ and the second diaphragm 25′ can be constructed in the same way as in the first or second embodiment described above, the same reference numerals are given to the parts that can be constructed in the same way, and their descriptions are omitted. In this embodiment, the first diaphragm 24′ is formed into a diaphragm portion 24b′ along the first extension portion 21b and a diaphragm portion 24c′ along the second extension portion 21c by providing a notch 24a′ adjacent to the middle portion 21a of the intermediate electrode body 21. Similarly, the second diaphragm 25′ is formed into a diaphragm portion 25b′ along the first extension portion 21b and a diaphragm portion 25c′ along the second extension portion 21c by providing a notch 25a′ adjacent to the middle portion 21a of the intermediate electrode body 21.

[0084] Even with the configuration described above, no problems will arise as long as the insulation between the intermediate electrode 21 and the first electrode 22, and between the intermediate electrode 21 and the second electrode 23, is guaranteed. In this case, even with notches 24a′ and 25a′, insulation performance can be guaranteed as long as the inner ends of each diaphragm portion 24b′, 24c′, 25b′, and 25c′ are positioned closer to the center (middle portion 21a side) than the inner ends of the first electrode 22 and the second electrode 23. That is, insulation performance can be guaranteed as long as the inner end portions of the first diaphragm 24b′ and the second diaphragm 25′ extend beyond the angular range of the inner ends of the first electrode 22 and the second electrode 23. Alternatively, an insulator can be disposed at the inner ends of the first electrode 22 and the second electrode 23 using the same structure and material as the aforementioned insulating edge portion 21d, or an extension portion of the insulator can be formed.

[0085] In addition, such as Figure 11 As shown by the double-dotted line, by making the outer edge (side edge) of the intermediate electrode body 20 protrude outward in the axial direction of the winding structure 20, and / or by positioning the outer edge (end edge) radially outward of the winding structure 20, leakage current can be reduced and insulation performance improved. In these cases, it is better to have the outer edge abut against the boundary (such as the inner surface mentioned above) of the axial and / or radially outward boundary of the receiving space of the winding structure 20.

[0086] <Fourth Implementation>

[0087] Next, refer to Figure 12 The energy storage device according to the fourth embodiment of the present invention will be described. In this embodiment, the components other than the intermediate electrode body 21, the first diaphragm 24, and the second diaphragm 25 can be constructed in the same way as in the first to third embodiments described above. Therefore, the same reference numerals are given to the parts that can be constructed in the same way, and their descriptions are omitted. In this embodiment, by providing adhesive layers 27 and 28 between the intermediate electrode body 21 and the first diaphragm 24 and the second diaphragm 25, the intermediate electrode body 21, the first diaphragm 24, and the second diaphragm 25 are integrally formed. The integral intermediate electrode body 21, the first diaphragm 24, and the second diaphragm 25 are then wound together with the first electrode body 22 and the second electrode body 23 as described above, thereby forming a wound structure 20. Here, the adhesive layers 27 and 28 can be made of various adhesive materials. In this way, the winding process can be simplified, and the winding shape of the wound structure can be formed neatly and with good reproducibility. Furthermore, in the above example, the intermediate electrode body 21 is integrated with the first diaphragm 24 and the second diaphragm 25. However, for example, the first diaphragm 24 may be integrated with the first electrode body 22, and / or the second diaphragm 25 may be integrated with the second electrode body 25, either together with or in place of the above configuration.

[0088] In addition, such as Figure 12 As shown by the double-dotted line, by making the outer edge (side edge) of the intermediate electrode body 20 protrude outward in the axial direction of the winding structure 20, and / or by positioning the outer edge (end edge) radially outward of the winding structure 20, leakage current can be reduced and insulation performance improved. In these cases, it is better to have the outer edge abut against the boundary (such as the inner surface mentioned above) of the axial and / or radially outward boundary of the receiving space of the winding structure 20.

[0089] <Fifth Implementation>

[0090] Next, refer to Figure 13 The energy storage device according to the fifth embodiment of the present invention will be described. In this embodiment, the components other than the intermediate electrode body 31 (intermediate portion 31a, first extension portion 31b, and second extension portion 31c) can be constructed in the same way as in the first to fourth embodiments described above. Therefore, the same reference numerals are given to the parts that can be constructed in the same way, and their descriptions are omitted. The intermediate electrode body 31 of this embodiment is composed of a plurality of electrode body layers 31h and 31i arranged in the thickness direction with a separator layer 31g between them. In the example shown in the figure, two electrode body layers 31h and 31i are arranged inside and outside with a separator layer 31g between them, but three or more electrode body layers can also be arranged with a separator layer between them. In this way, since the intermediate electrode body 31 is composed of a plurality of electrode bodies, it is possible to construct one or more energy storage functional units (third energy storage functional units) with only the intermediate electrode body 31, and thus it is expected to further realize high voltage. Here, the separator layer 31g can be made of the same material as the first separator 24 or the second separator 25.

[0091] In addition, such as Figure 13 As shown by the double-dotted line, by making the outer edge (side edge) of the intermediate electrode body 20 protrude outward in the axial direction of the winding structure 20, and / or by positioning the outer edge (end edge) on the radially outer side of the winding structure 20, leakage current can be reduced and insulation performance improved. In these cases, it is better to have the outer edge abut against the boundary (such as the inner surface mentioned above) of the axial and / or radially outer side of the receiving space of the winding structure 20. In this case, it is preferable to make the multiple electrode body layers 31h, 31i extend towards the outer periphery of the winding structure 30 through the diaphragm layer 31g, such that the diaphragm layer 31g and the electrode body layers 31h, 31i abut against the boundary (such as the inner surface mentioned above) of the receiving space, so that each layer is configured in a stepped shape.

[0092] <Sixth Implementation Method>

[0093] Next, refer to Figure 14The energy storage device according to the sixth embodiment of the present invention will be described. In this embodiment, the components other than the intermediate electrode body 41 (intermediate portion 41a, first extension portion 41b, and second extension portion 41c) can be configured in the same way as in the first to fifth embodiments described above. Therefore, the same reference numerals are given to the parts that can be configured in the same way, and their descriptions are omitted. In this embodiment, as... Figure 14 The configuration shown is such that the first electrode body 22 and the second electrode body 23 are respectively covered from the radial outer periphery by the outer peripheral portions 41j and 41k of the intermediate electrode body 41, separated by the first diaphragm 24 and the second diaphragm 25. That is, the outer peripheral portions 41j and 41k of the first extension portion 41b and the second extension portion 41c are formed to extend to a large angular range further outward than the outer periphery of the first electrode body 22 and the second electrode body 23. In this way, the first electrode body 22 and the second electrode body 23 are surrounded by the intermediate electrode body 41 throughout the entire circumference (full angular range) when viewed radially. This suppresses electrical leakage of the intermediate electrode body 41 beyond the first electrode body 22 and the second electrode body 23, thereby further improving insulation properties. In particular, it is preferable that the outer peripheral portions 41j and 41k of the intermediate electrode body 41 abut against the boundary of the receiving space (such as the aforementioned inner surface), as shown in the example. Furthermore, if, together with or replacing the above configuration, the outer peripheral portions 41j and 41k (e.g., their ends) of the intermediate electrode body 41 are configured (held or bonded) within the range 41L and 41M enclosed by the double-dotted lines in the figure to abut against the middle portion of the intermediate electrode body 41 disposed radially inside the outer peripheral portions 41j and 41k, the sealing effect of the electrolyte 5 into the winding structure can be enhanced, thereby further improving the insulation performance.

[0094] In this case, to ensure insulation between the electrodes, it is preferable that the outer peripheries of the first diaphragm 24 and the second diaphragm 25 are positioned between the first electrode body 22 and the second electrode body 23 and the intermediate electrode body 41 within a larger angular range than the first electrode body 22 and the second electrode body 23. Furthermore, to ensure insulation of the intermediate electrode body 41, the outer peripheries of the first diaphragm 24 and the second diaphragm 25 may be configured to extend outwards to a further outward periphery of the intermediate electrode body 41 within a larger angular range, or insulation may be ensured through the boundary of the receiving space (such as the aforementioned inner surface).

[0095] <Seventh Implementation>

[0096] Next, refer to Figure 15The energy storage device according to the seventh embodiment of the present invention will be described. In this embodiment, the components other than the intermediate electrode body 21" (intermediate portion 21a, first extension portion 21b", second extension portion 21c"), the first electrode body 22", and the second electrode body 23" can be configured in the same way as in the first to sixth embodiments described above. Therefore, the same reference numerals are given to the parts that can be configured in the same way, and their descriptions are omitted. In this embodiment, as Figure 15 As shown, in the first extension portion 21b" and the second extension portion 21c" of the intermediate electrode body 21", the aforementioned polarization electrode layer is not formed on the outer peripheral side surface that does not face the first electrode body 22" and the second electrode body 23" within the outermost circumferential angle range of the outer periphery of the winding structure, thereby providing the outer peripheral exposure areas 21bs and 21cs of the current collector 211. Furthermore, on the first electrode body 22", the aforementioned polarization electrode layer is not formed on the outer peripheral side surface that does not face the intermediate electrode body 21" within the outermost circumferential angle range of the outer periphery of the winding structure, thereby providing the outer peripheral exposure area 22s of the current collector 221. Similarly, on the second electrode body 23", the aforementioned polarization electrode layer is not formed on the outer peripheral side surface that does not face the intermediate electrode body 21" within the outermost circumferential angle range of the outer periphery of the winding structure, thereby providing the outer peripheral exposure area 23s of the current collector 231.

[0097] With the configuration described above, in each electrode body 21", 22", and 23", durability deterioration and deviation in watch back durability caused by the presence of polarized electrode layers opposite to and not opposite to the electrodes on the watch back can be suppressed. That is, in this embodiment, since a polarized electrode layer is not formed in the portion of each electrode body 21", 22", and 23" that is not opposite to other electrode bodies, problems caused by durability deterioration can be avoided. However, at the outer periphery of the wound structure, the ends of the two electrodes can be aligned at the same angular position to avoid the absence of a portion where the intermediate electrode 21" is not aligned with the first electrode 22" and the second electrode 23". For example, if the outer periphery ends of the first electrode 22" and the second electrode 23" are aligned at the same angular position with the outer periphery ends of the first extension portion 21b" and the second extension portion 21c" of the intermediate electrode 21", then it is not necessary to provide the aforementioned outer periphery exposed area on the first electrode 22" and the second electrode 23. It is sufficient to form the outer periphery exposed areas 21bs and 21cs only on the first extension portion 21b" and the second extension portion 21c".

[0098] <Eighth Implementation Method>

[0099] Next, refer to Figure 16The energy storage device according to the eighth embodiment of the present invention will be described. In this embodiment, the segmentation members 56 and 57 are arranged in a part of the internal structure of the winding structure 50, which differs from the embodiments described above. However, other configurations can be formed in the same way as those described in the embodiments above, and therefore, descriptions of parts that can be constructed in the same way without particular obstacles are omitted. In the winding structure 50 of this embodiment, as... Figure 16 As shown in (a), examples of configurations that can be constructed in the same manner as the embodiments described above include: intermediate electrode body 51 (intermediate portion 51a, first extension portion 51b, second extension portion 51c), first electrode body 52, second electrode body 53, first diaphragm 54, second diaphragm 55, container 3, holding member 26, sealing member 4 (not shown), electrolyte 5 (not shown), first external electrode 6, and second external electrode 7.

[0100] However, in this embodiment, the first diaphragm 54 is disposed between the first electrode body 52 and the second extension portion 51c, just like the first diaphragm 24 in the above embodiments. But unlike the first diaphragm 24 in the above embodiments, it is not disposed between the first electrode body 52 and the first extension portion 51b. Furthermore, the second diaphragm 55 is disposed between the second electrode body 53 and the first extension portion 51b, just like the second diaphragm 25 in the above embodiments. But unlike the second diaphragm 25 in the above embodiments, it is not disposed between the second electrode body 53 and the second extension portion 51c.

[0101] This embodiment is characterized in that, in the wound structure 50, a dividing member 56 is disposed between the first electrode body 52 and the first extension portion 51b, and a dividing member 57 is disposed between the second electrode body 53 and the second extension portion 51c. These dividing members 56 and 57, by being disposed in one of the radially inner and outer gaps between the intermediate electrode body 51 and the first electrode body 52 or the second electrode body 53 (in the example, the gaps are on the radially outer periphery), constitute opposing regions between the electrodes only in the other gap between the intermediate electrode body 51 and the first electrode body 52 or the second electrode body 53, thereby functioning as an electrical insulation barrier. Therefore, the dividing members 56 and 57 are constructed with materials and shapes (structures) that minimize leakage current between the intermediate electrode body 51 and the first electrode body 52 or the second electrode body 53 in the aforementioned gap, ensuring voltage withstand characteristics. Therefore, the dividing members 56 and 57 preferably possess electrolyte blocking and electrical insulation properties. That is, the dividing members 56 and 57 possess blocking properties that prevent electrolyte (ions) from passing through, and are themselves electrically insulating. The aforementioned dividing components 56 and 57 are preferably made of synthetic resin. Examples of synthetic resins include polyphenylene sulfide (PPS), polyimide (PI), aramid (all-aromatic polyamide), polyetheretherketone (PEEK), polyethylene terephthalate (PET), polytetrafluoroethylene (PTFE), polypropylene (PP), and polyethylene (PE).

[0102] Furthermore, as a preferred configuration of the aforementioned wound structure 50, the dividing members 56 and 57 are preferably sheet-like. Moreover, it is preferable that when the electrolyte is introduced into the wound structure, the dividing members do not allow the electrolyte and its ions to pass through. In particular, it is preferable that the electrolyte and its ions are impermeable and non-retaining. For example, they can be made of a sheet without voids. This allows for a more reliable reduction of leakage current caused by the electrolyte, further improving the insulation performance of the device. From these viewpoints, preferred synthetic resin sheets include fluoropolymer sheets such as polytetrafluoroethylene (PTFE), perfluoroalkoxyalkylene (PFA), perfluoroethylene-propylene copolymer (FEP), polyvinylidene fluoride (PVDF), ethylene-tetrafluoroethylene copolymer (ETFE), and polychlorotrifluoroethylene (PCTFE).

[0103] As described later, when using highly fluid electrolytes such as electrolyte solutions, it is preferable that the dividing components 56 and 57 have surfaces that repel electrolytes. For example, the aforementioned fluororesin sheet is preferred as the surface material. Alternatively, a surface layer with electrolyte-repellent properties can be formed on the surface by applying a coating or the like. Regarding the degree of electrolyte repulsion, it is preferable that the contact angle θ relative to the target electrolyte (liquid) is 80 degrees or more, and particularly preferably an angle exceeding 90 degrees (obtuse angle). Typically, the contact angle of fluororesin is around 100 degrees. In this way, by making the surfaces of the dividing components 56 and 57 have low wettability relative to the electrolyte, even if there are small gaps between the dividing components 56 and 57 and surrounding components, the electrolyte is unlikely to exceed the receiving area defined by the dividing components 56 and 57 (it is difficult to pass through the gap), thus achieving an improved insulation characteristic effect such as reducing leakage current.

[0104] As described above, the dividing components 56 and 57 are made of a gapless sheet with electrical insulation properties. When the dividing components 56 and 57 are made of a sheet of synthetic resin, as described above, to ensure electrical insulation and impermeability to the electrolyte (ions), and to achieve the most compact construction possible, their thickness is preferably in the range of 5 μm to 1 mm, particularly preferably in the range of 10 μm to 500 μm. More preferably, it is in the range of 20 μm to 200 μm. If the thickness is less than the above ranges, the electrolyte or its ions can easily pass through; if the thickness exceeds the above ranges, the winding properties during manufacturing deteriorate, which is also detrimental to the compactness of the energy storage device.

[0105] However, even in this embodiment, the intermediate electrode body 51, the first electrode body 52, and the second electrode body 53 can be constructed as described above using a laminated structure of current collectors 511, 521, 531 and polarization electrode layers 512, 513, 522, 532. However, in this embodiment, as described above, since a dividing member 56 is interposed between the first electrode body 52 and the first extension 51b, and a dividing member 57 is interposed between the second electrode body 53 and the second extension 51c, therefore, as... Figure 16 As shown in (b), the opposing regions for the energy storage function of the intermediate electrode body 51, the first electrode body 52, and the second electrode body 53 are only on one side separated by the first diaphragm 54 and the second diaphragm 55 (the inner peripheral side in the example). The opposing regions for the energy storage function are not formed on the side separated by the dividing members 56 and 57 (the outer peripheral side in the example). Therefore, in this embodiment, polarized electrode layers 512, 513, 522, and 532 are laminated only on the opposing region side, and no polarized electrode layers are formed on the dividing member 56 and 57 side. This reduces the non-opposing regions of the polarized electrode layers, thereby suppressing durability degradation and deviations in surface and back durability caused by these non-opposing regions.

[0106] According to this embodiment, by providing a dividing member 56, 57 with electrolyte blocking and electrical insulation properties in one of the two gaps between the intermediate electrode body 51 and the first electrode body 52 and the second electrode body 53, electrical leakage between the two energy storage structural units arranged in series in the winding structure 50 can be reduced. In particular, when the electrolyte 5 is contained in the winding structure 50 as in this embodiment, electrical short circuits caused by the electrolyte 5 can be suppressed, thereby reducing leakage current and improving withstand voltage characteristics. In particular, by arranging the dividing members 56, 57 in the same radial and inner side (outer peripheral side in the example) of the gap between the intermediate electrode body 51 and the first electrode body 52 and the second electrode body 53 as in this embodiment, the structural and functional imbalance between the energy storage functional units formed between the intermediate electrode body and the first electrode body 52 and the energy storage functional units formed between the intermediate electrode body and the second electrode body 53 can be reduced, and the symmetry of the energy storage functional units can be improved as in the example.

[0107] From the viewpoint of improving insulation properties, it is preferable that the outer edges (side edges) of the dividing members 56 and 57 in this embodiment protrude further outward in the axial direction of the winding structure 50 than at least one (preferably both) of the intermediate electrode body 51 and the first electrode body 52 or the second electrode body 53. In particular, it is preferable that the two outer edges (two side edges) of the dividing members 56 and 57 protrude further outward in the axial direction of the winding structure 50 than at least one (preferably both) of the intermediate electrode body 51 and the first electrode body 52 or the second electrode body 53. Furthermore, when the winding structure 50 is housed within a storage space formed by a frame consisting of a container 3 and a sealing member 4, or by a retaining member 26 inside the frame, it is preferable that the outer edges (side edges) abut (fix) against the boundary of the storage space in the axial direction.

[0108] Furthermore, from the viewpoint of improving insulation properties, it is preferable that the outer edges (end edges) 56e and 57e of the segmented components 56 and 57 protrude further radially outward from the winding structure 50 than at least one (preferably both) of the intermediate electrode body 51 and the first electrode body 52 or the second electrode body 53. Additionally, as shown in the example figure, it is preferable that the outer edges (outer end edges) of the intermediate electrode body 51, the first electrode body 52, or the second electrode body 53 have a structure where the outer peripheral portions (the portions extending to the end edges 56e and 57e) of the segmented components 56 and 57 are covered from the outer peripheral side. Furthermore, when the winding structure 50 is housed within a storage space formed by a frame consisting of a container 3 and a sealing member 4, or by a retaining member 26 inside the frame, as shown in the example figure, the aforementioned outer edges (radial end edges) 56e and 57e preferably abut (or are more preferably fixed) against the radially outer boundary of the storage space. Furthermore, from the viewpoint of improving insulation properties, it is preferable that the radial inner edges (inner end edges) of the aforementioned dividing members 56 and 57 are also positioned to extend further into the inner periphery of the winding structure 50 than the first electrode body 52 or the second electrode body 53, respectively. Additionally, it is preferable that the inner edges (inner end edges) of the intermediate electrode body 51, the first electrode body 52, or the second electrode body 53 are covered from the inner periphery by the inner edges of the dividing members 56 and 57. In particular, to further improve insulation properties, it is best to... Figure 16 As shown in (a), the inner edges of the dividing members 56 and 57 abut against the inner periphery of the middle portion 51a of the intermediate electrode body 51 (for better connection and fixation). Alternatively, the inner edges of the dividing members 56 and 57 may also abut against the inner periphery of the first diaphragm 54 and the second diaphragm 55 (for better connection and fixation). However, it is also possible to... Figure 16 As shown by the dashed line in (b), the inner edges of the dividing parts 56 and 57 are separated from the intermediate electrode body 51 or the diaphragms 54 and 55.

[0109] In this embodiment, the winding structure 50 preferably has a structure in which the outer peripheral portions of the intermediate electrode body 51, the first electrode body 52, and the second electrode body 53, as shown in the example, are covered from the radially outer peripheral side by the outer peripheral portions of the divided components 56 and 57 (the portions reaching the radial end edges 56e and 57e). Furthermore, it is preferable that, regardless of the outer peripheral portions of the divided components 56 and 57, the outer peripheral portions of the first diaphragm 54 and the second diaphragm 55 extend further outward than the outer peripheral portions of the intermediate electrode body 51, the first electrode body 52, and the second electrode body 53.

[0110] Furthermore, as the aforementioned retaining member 26, it is preferable that the electrode bodies (especially the polarized electrode layers) or the diaphragms are not connected by an adhesive layer between the regions separated by the dividing members 56 and 57, so as to prevent the adhesive layer from hindering electrical insulation.

[0111] <Ninth Implementation Method>

[0112] Next, refer to Figure 17 The energy storage device according to the ninth embodiment of the present invention will be described. In this embodiment, similar to the eighth embodiment, dividing members 56' and 57' are arranged in a portion of the internal structure of the wound structure 50', but differ from the eighth embodiment in the following aspects: Specifically, in this embodiment, dividing member 56' is arranged between the first electrode body 52 and the second extension portion 51c, and dividing member 57' is arranged between the second electrode body 53 and the first extension portion 51b. On the other hand, a first diaphragm 54' is arranged between the first electrode body 52 and the first extension portion 51b, and a second diaphragm 55' is arranged between the second electrode body 53 and the second extension portion 51c. In this embodiment, dividing members 56' and 57' are each arranged in the inner circumferential gap of one of a pair of radially inner and outer gaps between the intermediate electrode body 51 and the first electrode body 52 or the second electrode body 53.

[0113] Regarding the aforementioned segmented components 56' and 57', since other configurations can be formed in the same way as in the eighth embodiment, it is obvious that the same configuration can be adopted without particular obstacles, therefore their description is omitted. Furthermore, the winding structure 50' of this embodiment can also achieve the same effects as in the eighth embodiment. Furthermore, for Figure 17 The polarization electrode layers 512, 513, 521, 531 shown in (b) are laminated with respect to the current collectors 511, 521, 531. The polarization electrode layers are formed in the portions that are opposite each other with the first diaphragm 54' and the second diaphragm 55' in between, and in the portions where no polarization electrode layers are formed, and their structure and function are the same as in the eighth embodiment.

[0114] (Industrial applicability)

[0115] Furthermore, the energy storage device of the present invention is not limited to the examples shown in the figures above, and various modifications can be made without departing from the spirit of the invention. For example, the above embodiments have described examples of double-layer capacitors; however, by forming insulating films such as oxide films on the surfaces of each electrode body, the internal electrode structure of the above-described wound structure can also be readily applied to electrolytic capacitors, as will be apparent to those skilled in the art. In addition, the internal electrode structure of the present invention can be applied to various capacitor-type energy storage devices such as other types of capacitors. Furthermore, the internal electrode structure of the present invention can also be applied to chemical energy storage devices such as batteries. Moreover, unless there are particular obstacles, the configurations of the various parts of the above embodiments can be arbitrarily combined and configured.

[0116] In this specification, an example of an inductive energy storage device in which leads (first external terminals and second external terminals) are wound around internal electrodes (first electrode body and second electrode body) is illustrated and described as an embodiment. However, the energy storage device of the present invention is not limited to the inductive type described above. It can also be configured as an inductive energy storage device in which leads (first external terminals and second external terminals) are installed at the end edges of the internal electrodes (first electrode body and second electrode body) in the axial direction of the wound structure.

[0117] Furthermore, in the energy storage device of the present invention, as described above, two energy storage functional units are connected in series with an intermediate electrode body 21 in between: a first energy storage functional unit consisting of an intermediate electrode body 21 and a first electrode body 22, and a second energy storage functional unit consisting of an intermediate electrode body 21 and a second electrode body 23. In this case, by using an anisotropic ion conductor 5, which has high ion conductivity in the thickness direction and low ion conductivity in the planar direction, adverse conditions caused by shared electrolyte effects such as self-discharge current due to short circuits generated between the aforementioned energy storage functional units can be reduced, further reducing electrical leakage in the above-described embodiment. The anisotropic ion conductor must have a conductivity along the surface of each electrode body that is less than the conductivity perpendicular to the surface of each electrode body; particularly preferably, an anisotropic ion conductor whose conductivity along the surface of each electrode body is less than 1 / 10 of the conductivity perpendicular to the surface of each electrode body is used.

Claims

1. An energy storage device comprising a wound structure and a first external terminal and a second external terminal connected to the wound structure, characterized in that, The winding structure includes: A strip-shaped intermediate electrode body, with a first extension portion and a second extension portion extending to both sides of the intermediate portion as the center in the extension direction, respectively wraps around the intermediate portion in the same direction. A first electrode body is electrically connected to the first external terminal and is disposed between the first extension portion located on the inner peripheral side and the second extension portion located on the outer peripheral side, and extends from near the middle portion to the outer peripheral side. The second electrode body is electrically connected to the second external terminal and is disposed between the second extension portion located on the inner peripheral side and the first extension portion located on the outer peripheral side, and extends from the vicinity of the middle portion to the outer peripheral side. A first diaphragm is disposed between the intermediate electrode body and the first electrode body; as well as A second diaphragm is disposed between the intermediate electrode body and the second electrode body; The outer edge of the intermediate electrode protrudes further outward in the axial direction of the winding structure compared to the first and second electrodes of the winding structure.

2. The energy storage device as described in claim 1, characterized in that, The winding structure is disposed within the storage space; The outer edge of the intermediate electrode body abuts against the boundary of the storage space located outside the axial direction.

3. An energy storage device comprising a wound structure and a first external terminal and a second external terminal connected to the wound structure, characterized in that, The winding structure includes: A strip-shaped intermediate electrode body, with a first extension portion and a second extension portion extending to both sides of the intermediate portion as the center in the extension direction, respectively wraps around the intermediate portion in the same direction. A first electrode body is electrically connected to the first external terminal and is disposed between the first extension portion located on the inner peripheral side and the second extension portion located on the outer peripheral side, and extends from near the middle portion to the outer peripheral side. The second electrode body is electrically connected to the second external terminal and is disposed between the second extension portion located on the inner peripheral side and the first extension portion located on the outer peripheral side, and extends from the vicinity of the middle portion to the outer peripheral side. A first diaphragm is disposed between the intermediate electrode body and the first electrode body; as well as A second diaphragm is disposed between the intermediate electrode body and the second electrode body; The outer edge of the intermediate electrode is positioned radially outward from the winding structure compared to the first and second electrodes in the winding structure.

4. The energy storage device as described in claim 3, characterized in that, The outer edge of the intermediate electrode protrudes further outward in the axial direction of the winding structure compared to the first and second electrodes of the winding structure.

5. The energy storage device as described in claim 4, characterized in that, The winding structure is disposed within the storage space; The outer edge of the intermediate electrode body abuts against the boundary of the storage space located outside the axial direction.

6. The energy storage device as described in claim 3, characterized in that, The winding structure is disposed within the storage space; The outer edge of the intermediate electrode body abuts against the radially outer boundary of the storage space.

7. The energy storage device as described in any one of claims 1 to 6, characterized in that, The outer edge of the intermediate electrode is insulated.

8. The energy storage device as described in claim 7, characterized in that, Electrolytes are introduced into the wound structure; The outer edge of the intermediate electrode is the part that is more difficult to retain the electrolyte or its ions, or the part that is more difficult to allow the electrolyte or its ions to pass through, compared to the main body of the intermediate electrode.

9. An energy storage device comprising a wound structure and a first external terminal and a second external terminal connected to the wound structure, characterized in that... The winding structure includes: A strip-shaped intermediate electrode body, with a first extension portion and a second extension portion extending to both sides of the intermediate portion as the center in the extension direction, respectively wraps around the intermediate portion in the same direction. A first electrode body is electrically connected to the first external terminal and is disposed between the first extension portion located on the inner peripheral side and the second extension portion located on the outer peripheral side, and extends from near the middle portion to the outer peripheral side. The second electrode body is electrically connected to the second external terminal and is disposed between the second extension portion located on the inner peripheral side and the first extension portion located on the outer peripheral side, and extends from the vicinity of the middle portion to the outer peripheral side. A first diaphragm is disposed between the intermediate electrode body and the first electrode body; as well as A second diaphragm is disposed between the intermediate electrode body and the second electrode body; The wound structure has a structure in which the outer peripheries of the first electrode and the second electrode are covered from the radial outer periphery by the outer periphery of the intermediate electrode.

10. The energy storage device as described in claim 9, characterized in that, The outer peripheral portions of the first diaphragm and the second diaphragm are respectively located in a larger angular range on the outer periphery compared to the first electrode body and the second electrode body.

11. An energy storage device comprising a wound structure and a first external terminal and a second external terminal connected to the wound structure, characterized in that, The winding structure includes: A strip-shaped intermediate electrode body, with a first extension portion and a second extension portion extending to both sides of the intermediate portion as the center in the extension direction, respectively wraps around the intermediate portion in the same direction. A first electrode body is electrically connected to the first external terminal and is disposed between the first extension portion located on the inner peripheral side and the second extension portion located on the outer peripheral side, and extends from near the middle portion to the outer peripheral side. The second electrode body is electrically connected to the second external terminal and is disposed between the second extension portion located on the inner peripheral side and the first extension portion located on the outer peripheral side, and extends from the vicinity of the middle portion to the outer peripheral side. A first diaphragm is disposed between the intermediate electrode body and the first electrode body; as well as A second diaphragm is disposed between the intermediate electrode body and the second electrode body; The intermediate electrode body is composed of multiple electrode body layers arranged with a membrane layer between them.

12. An energy storage device comprising a wound structure and a first external terminal and a second external terminal connected to the wound structure, characterized in that, The winding structure includes: A strip-shaped intermediate electrode body, with a first extension portion and a second extension portion extending to both sides of the intermediate portion as the center in the extension direction, respectively wraps around the intermediate portion in the same direction. A first electrode body is electrically connected to the first external terminal and is disposed between the first extension portion located on the inner peripheral side and the second extension portion located on the outer peripheral side, and extends from near the middle portion to the outer peripheral side. The second electrode body is electrically connected to the second external terminal and is disposed between the second extension portion located on the inner peripheral side and the first extension portion located on the outer peripheral side, and extends from the vicinity of the middle portion to the outer peripheral side. A first diaphragm is disposed between the intermediate electrode body and the first electrode body; as well as A second diaphragm is disposed between the intermediate electrode body and the second electrode body; The first diaphragm is disposed in one of a pair of radially inner and outer gaps between the intermediate electrode body and the first electrode body respectively disposed radially inner and outer, and a first dividing member with electrolyte blocking property and electrical insulation property is disposed in the other gap. The second diaphragm is disposed in one of a pair of radially inner and outer gaps between the intermediate electrode body and the second electrode body respectively disposed radially inner and outer, and a second dividing member with electrolyte blocking and electrical insulation is disposed in the other gap.

13. The energy storage device as described in claim 12, characterized in that, The first dividing member is disposed in the gap on one side of the radial inner and outer sides, and the second dividing member is also disposed in the gap on the same side as the first dividing member.

14. The energy storage device as described in claim 12, characterized in that, Electrolytes are introduced into the wound structure; The first dividing component and the second dividing component possess the properties of being impermeable to and not retaining the electrolyte and its ions.

15. The energy storage device as described in claim 14, characterized in that, The electrolyte is in liquid form; The first dividing component and the second dividing component have surfaces with a contact angle of 80 degrees or more with the electrolyte.

16. The energy storage device as described in claim 12, characterized in that, The outer edges of the first segment and the second segment protrude further toward the axis of the winding structure than either the intermediate electrode body or at least one of the first electrode body or the second electrode body.

17. The energy storage device as described in claim 16, characterized in that, The winding structure is disposed within the storage space; The outer edges of the first dividing component and the second dividing component respectively abut against the boundary of the storage space located outside the axial direction.

18. The energy storage device as described in claim 12, characterized in that, The outer edges of the first segment and the second segment are respectively disposed at a position further radially outward from the winding structure than at least one of the intermediate electrode body and the first electrode body and the second electrode body of the winding structure.

19. The energy storage device as described in claim 18, characterized in that, The winding structure is disposed within the storage space; The outer edges of the first dividing component and the second dividing component respectively abut against the radially outer boundary of the storage space.

20. The energy storage device as described in any one of claims 12 to 19, characterized in that, The inner edges of the first segment and the second segment are respectively configured to extend further inward than the inner edges of the first electrode and the second electrode.

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