Electrode bodies and energy storage devices

Abstract

To facilitate disassembling an electrode body so as to separate a pair of electrode plates.SOLUTION: An electrode body disclosed herein is a wound body in which a positive electrode plate 10 and a negative electrode plate 20 are wound across a first separator 30A and a second separator 30B. The first separator 30A is adhered to the positive electrode plate 10 and not to the negative electrode plate 20. On the other hand, the second separator 30B is adhered to the negative electrode plate 20 and not to the positive electrode plate 10. Both of a second terminal part 30Be of the second separator 30B and a first terminal part 30Ae of the first separator 30A are exposed to an outer surface of the wound body. A separator wound part 40s in which the first separator 30A and the second separator 30B are wound includes a non-adhesion area 30X where the separators are not adhered to each other. A first adhesive tape 80 is attached to the outermost surface of the wound body, and a first peeling part 82 is formed at one end part of the first adhesive tape 80.SELECTED DRAWING: Figure 10

Description

Technical Field

[0001] The technology disclosed herein relates to an electrode body and a power storage device.

Background Art

[0002] A power storage device such as a lithium-ion secondary battery includes, for example, an electrode body having a pair of electrode plates (a positive electrode plate and a negative electrode plate), and a battery case that houses the electrode body. As an example of the electrode body of this power storage device, a wound electrode body in which a positive electrode plate and a negative electrode plate are wound through two separators can be mentioned. Patent Documents 1 and 2 disclose this type of wound electrode body.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, with the increasing awareness of environmental problems in recent years, a recycling technology for recovering and reusing valuable metals from used power storage devices has attracted attention. In this recycling technology, first, the electrode body is taken out from the used power storage device. Next, this electrode body is immersed in an acid solution or the like to obtain a metal solution. Then, various separation treatments (such as neutralization precipitation and solvent extraction) are performed on this metal solution. Thereby, the desired valuable metal can be recovered from the electrode body.

[0005] However, in the regeneration technology described above, both metal components derived from the positive electrode plate and metal components derived from the negative electrode plate are included in the metal solution. In this case, the number and types of separation processes required to recover valuable metals from the metal solution increase. As a result, this may lead to a decrease in the recovery rate of valuable metals and an increase in regeneration costs. For this reason, in the field of regeneration technology for energy storage devices, there is a need for technology that can properly dismantle the electrode body and separate the pair of electrode plates. [Means for solving the problem]

[0006] The electrode body disclosed herein comprises a strip-shaped first electrode plate, a strip-shaped first separator, a strip-shaped second electrode plate, and a strip-shaped second separator. This electrode body is a wound body in which the first electrode plate and the second electrode plate are wound around the first and second separators. The first separator is bonded to the first electrode plate but not to the second electrode plate, and the second separator is bonded to the second electrode plate but not to the first electrode plate. Furthermore, in this electrode body, a separator wound section is formed on the outer circumference of the wound body in which only the first and second separators are wound, and the first separator is wound around the outermost circumference of the separator wound section. The second end, which is the winding end of the second separator, extends from the first end, which is the winding end of the first separator, and is exposed on the outer surface of the wound body. The separator winding portion described above has a first opposing portion between the inner surface of the first separator and the outer surface of the second separator, and a non-adhesive region on at least one of the second opposing portions between the outer surface of the first separator and the inner surface of the second separator, where the first separator and the second separator are not adhered to each other. The non-adhesive region extends inward in the winding direction from the first end portion and / or the second end portion. In the electrode body disclosed herein, a first adhesive tape spanning both the first and second end portions is attached to the outermost surface of the winding body, and a first release portion is formed on at least one of the ends of the first adhesive tape in the circumferential direction, which does not adhere to the outermost surface of the winding body.

[0007] In the electrode body disclosed herein, a first separator and a first electrode plate are bonded together, and a second separator and a second electrode plate are bonded together. However, there is no bond between the first separator and the second electrode plate, and no bond between the second separator and the first electrode plate. An electrode body with this configuration can be easily separated into a first electrode plate bonded to the first separator and a second electrode plate bonded to the second separator by unwinding the winding of the two separators.

[0008] In addition, the electrode body disclosed herein also has a structure that facilitates the unwinding of the two separators. Specifically, in a typical wound electrode body, a separator winding section is formed on the outer circumference where only two separators are wound without an electrode plate in between. If the separators are bonded together throughout this separator winding section, it becomes very difficult to unwind the separators. Therefore, in the electrode body disclosed herein, the second end of the second separator extends from the first end of the first separator wound on the outermost circumference of the separator winding section. The separator winding section has non-adhesive regions that extend inward in the winding direction from the first end and / or the second end. This makes it possible to easily unwind the separators by grasping and pulling the first end and / or the second end.

[0009] Furthermore, in the electrode body disclosed herein, a first release portion is formed on at least one end of the first adhesive tape that secures the first and second ends, and does not adhere to the outermost surface of the winding body. This prevents damage to the first and second ends when peeling off the first adhesive tape. As a result, the first and / or second ends can be properly grasped when unwinding the separator.

[0010] As described above, the electrode body disclosed herein allows for easy unwinding of the separator in the outer periphery (separator winding portion) of the wound electrode body. Once the separator winding is unwinded, the electrode body can be easily separated into a first electrode plate bonded to the first separator and a second electrode plate bonded to the second separator. As a result, the pair of electrode plates can be individually provided for recycling, contributing to improved efficiency in recovering valuable metals and reduced recycling costs. [Brief explanation of the drawing]

[0011] [Figure 1] This is a schematic perspective view of an energy storage device. [Figure 2] This is a schematic longitudinal cross-section along the line II-II in Figure 1. [Figure 3] This is a schematic longitudinal cross-section along the line III-III in Figure 1. [Figure 4] This is a schematic cross-sectional view along the line IV-IV in Figure 1. [Figure 5] This is a schematic perspective view showing the electrode body attached to the sealing plate. [Figure 6] This is a schematic perspective view showing an electrode body to which a positive electrode second current collector and a negative electrode second current collector are attached. [Figure 7] This is a schematic diagram showing the configuration of the electrode body according to the first embodiment. [Figure 8] This is a schematic front view showing the electrode body according to the first embodiment. [Figure 9] This is a schematic longitudinal cross-section along the line IX-IX in Figure 8. [Figure 10] Figure 9 is a magnified cross-sectional view of the vicinity of the adhesive tape on the electrode body shown. [Figure 11] Figure 9 shows a cross-sectional view of the electrode assembly after it has been disassembled. [Figure 12] This is a magnified cross-sectional view of the vicinity of the adhesive tape of an electrode body according to another embodiment. [Figure 13] Figure 12 shows a cross-sectional view of the electrode assembly after it has been disassembled. [Figure 14] This is a schematic front view showing an electrode body according to another embodiment. [Figure 15] It is a front view schematically showing an electrode body according to another embodiment. [Figure 16] It is a front view schematically showing an electrode body according to another embodiment. [Figure 17] It is a front view schematically showing an electrode body according to another embodiment.

Embodiments for Carrying out the Invention

[0012] Hereinafter, embodiments of the technology disclosed herein will be described with reference to the drawings. In addition, matters other than those specifically mentioned in this specification, which are necessary for implementing the technology disclosed herein (for example, general configurations and manufacturing processes of batteries), can be grasped as design matters of those skilled in the art based on the prior art in the relevant field. The technology disclosed herein can be implemented based on the content disclosed in this specification and common technical knowledge in the relevant field. Note that the notation "A to B" indicating a range in this specification includes the meaning of "A or more and B or less", as well as the meaning of "preferably larger than A" and "preferably smaller than B".

[0013] Note that the "power storage device" in this specification is a concept including a device in which a charge carrier moves between a pair of electrodes (a positive electrode and a negative electrode) through an electrolytic solution to cause a charge-discharge reaction. That is, the power storage device in the technology disclosed herein includes secondary batteries such as lithium-ion secondary batteries, nickel-metal hydride batteries, nickel-cadmium batteries, and capacitors such as lithium-ion capacitors and electric double-layer capacitors.

[0014] Furthermore, in the figures referenced herein, the symbol X indicates the "depth direction," the symbol Y indicates the "width direction," and the symbol Z indicates the "height direction." In the depth direction X, F indicates "front," and Rr indicates "rear." In the width direction Y, L indicates "left," and R indicates "right." In the height direction Z, U indicates "up," and D indicates "down." However, these directions are defined for explanatory purposes only and are not intended to limit the installation configurations when using the energy storage devices disclosed herein.

[0015] <First Embodiment> 1. Structure of an energy storage device The structure of the energy storage device will be described below, followed by a description of the electrode body used in the energy storage device. Figure 1 is a schematic perspective view of the energy storage device. Figure 2 is a schematic longitudinal cross-sectional view along the line II-II in Figure 1. Figure 3 is a schematic longitudinal cross-sectional view along the line III-III in Figure 1. Figure 4 is a schematic transverse cross-sectional view along the line IV-IV in Figure 1. Figure 5 is a schematic perspective view of the electrode body attached to the sealing plate. Figure 6 is a schematic perspective view of the electrode body to which the positive electrode second current collector and the negative electrode second current collector are attached. Figure 7 is a schematic diagram showing the configuration of the electrode body according to the first embodiment. Figure 8 is a schematic front view showing the electrode body according to the first embodiment. Figure 9 is a schematic longitudinal cross-sectional view along the line IX-IX in Figure 8. Figure 10 is an enlarged cross-sectional view of the electrode body shown in Figure 9 near the adhesive tape. Figure 11 is a cross-sectional view of the electrode body shown in Figure 9 when disassembled.

[0016] As shown in Figure 2, the energy storage device 100 comprises an electrode body 40 and a battery case 50 that houses the electrode body 40. The specific configuration of such energy storage device 100 will be described below. (1) Battery case The battery case 50 is a housing that contains the electrode body 40. Although not shown in the figure, a non-aqueous electrolyte is also contained inside the battery case 50. The battery case 50 shown in Figure 1 has a flattened, bottomed rectangular parallelepiped (square) shape. The battery case 50 can be made of any conventionally known material without any particular restrictions. For example, the battery case 50 may be made of metal. Examples of materials for such a battery case 50 include aluminum, aluminum alloy, iron, iron alloy, etc.

[0017] As shown in Figures 1 and 2, the battery case 50 comprises an outer casing 52 and a sealing plate 54. The outer casing 52 is a flat, bottomed, rectangular container with an opening 52h on its top surface. The outer casing 52 comprises a bottom wall 52a that is approximately rectangular in plan, a pair of long side walls 52b extending upward U in the height direction Z from the long side of the bottom wall 52a, and a pair of short side walls 52c extending upward U in the height direction Z from the short side of the bottom wall 52a. The sealing plate 54 is a plate-like member that is approximately rectangular in plan and closes the opening 52h of the outer casing 52. The outer peripheral edge of the sealing plate 54 is joined (e.g., welded) to the outer peripheral edge of the opening 52h of the outer casing 52. This creates a battery case 50 with an airtight seal inside. The sealing plate 54 is also provided with a liquid injection hole 55 and a gas discharge valve 57. The electrolyte injection hole 55 is a through-hole provided for injecting electrolyte into the inside of the sealed battery case 50. The electrolyte injection hole 55 is sealed by the sealing member 56 after the electrolyte has been injected. The gas discharge valve 57 is a thin-walled section designed to rupture (open) when a large amount of gas is generated inside the battery case 50, thereby discharging the gas.

[0018] (2) Electrolyte As described above, the battery case 50 contains not only the electrode body 40 but also an electrolyte (not shown). Most of the electrolyte permeates into the interior of the electrode body 40. Any electrolyte used in conventionally known energy storage devices can be used without particular limitations. For example, a non-aqueous electrolyte can be used, which is obtained by dissolving a support salt in a non-aqueous solvent. Examples of such non-aqueous solvents include carbonate-based solvents such as ethylene carbonate, dimethyl carbonate, and ethyl methyl carbonate. An example of a support salt is a fluorine-containing lithium salt such as LiPF6.

[0019] (3) Electrode terminal Furthermore, a positive electrode terminal 60 is attached to one end of the sealing plate 54 in the width direction Y (the left side in Figures 1 and 2). This positive electrode terminal 60 is connected to a plate-shaped positive electrode external conductive member 62 on the outside of the battery case 50. On the other hand, a negative electrode terminal 65 is attached to the other end of the sealing plate 54 in the width direction Y (the right side in Figures 1 and 2). A plate-shaped negative electrode external conductive member 67 is attached to this negative electrode terminal 65. These external conductive members (positive electrode external conductive member 62 and negative electrode external conductive member 67) are connected to other energy storage devices and external equipment via external connection members (bus bars, etc.). It is preferable that the external conductive members are made of a metal with excellent conductivity (aluminum, aluminum alloy, copper, copper alloy, etc.).

[0020] (4) Electrode current collector As shown in Figures 3 to 5, this energy storage device 100 houses multiple (3) electrode bodies 40 within the battery case 50. The detailed structure will be described later, but each electrode body 40 is provided with a positive electrode tab group 42 and a negative electrode tab group 44 (see Figures 7 and 8). As shown in Figure 4, these electrode tab groups (positive electrode tab group 42 and negative electrode tab group 44) are bent while joined together with the electrode current collectors (positive electrode current collector 70 and negative electrode current collector 75).

[0021] Specifically, each group of positive electrode tabs 42 of the multiple electrode bodies 40 is connected to the positive electrode terminal 60 via a positive electrode current collector 70. This positive electrode current collector 70 is housed inside the battery case 50. As shown in Figures 2 and 5, the positive electrode current collector 70 comprises a positive electrode first current collector 71, which is a plate-shaped conductive member extending in the width direction Y along the inner surface of the sealing plate 54, and a plurality of positive electrode second current collectors 72, which are plate-shaped conductive members extending in the height direction Z. The lower end portion 60c of the positive electrode terminal 60 is inserted into the battery case 50 through the terminal insertion hole 58 of the sealing plate 54 and connected to the positive electrode first current collector 71 (see Figure 2). On the other hand, as shown in Figures 4 to 6, this energy storage device 100 is provided with a number of positive electrode second current collectors 72 corresponding to the number of electrode bodies 40. Each positive electrode second current collector 72 is connected to the group of positive electrode tabs 42 of the electrode body 40. Then, as shown in Figures 4 and 5, the group of positive electrode tabs 42 of the electrode body 40 is bent so that the second positive electrode current collector 72 and one side surface 40a of the electrode body 40 face each other. This electrically connects the upper end of the second positive electrode current collector 72 and the first positive electrode current collector 71.

[0022] On the other hand, each group of negative electrode tabs 44 of the multiple electrode bodies 40 is connected to the negative electrode terminal 65 via a negative electrode current collector 75. This negative electrode connection structure is substantially the same as the positive electrode connection structure described above. Specifically, the negative electrode current collector 75 comprises a negative electrode first current collector 76, which is a plate-shaped conductive member extending in the width direction Y along the inner surface of the sealing plate 54, and a plurality of negative electrode second current collectors 77, which are plate-shaped conductive members extending in the height direction Z (see Figures 2 and 5). The lower end portion 65c of the negative electrode terminal 65 is inserted into the battery case 50 through the terminal insertion hole 59 and connected to the negative electrode first current collector 76 (see Figure 2). On the other hand, each of the plurality of negative electrode second current collectors 77 is connected to the group of negative electrode tabs 44 of the electrode body 40 (see Figures 4 to 6). The negative electrode tab group 44 is then bent so that the negative electrode second current collector 77 and the other side surface 40b of the electrode body 40 face each other. This electrically connects the upper end of the negative electrode second current collector 77 to the negative electrode first current collector 76. Furthermore, metals with excellent conductivity (aluminum, aluminum alloy, copper, copper alloy, etc.) can preferably be used for the electrode current collectors (positive electrode current collector 70 and negative electrode current collector 75).

[0023] (5) Insulating material Furthermore, in this energy storage device 100, various insulating members are attached to prevent electrical conductivity between the electrode body 40 and the battery case 50. Specifically, an external insulating member 92 is interposed between the positive electrode external conductive member 62 (negative electrode external conductive member 67) and the outer surface of the sealing plate 54 (see Figure 1). This prevents the positive electrode external conductive member 62 and the negative electrode external conductive member 67 from making electrical contact with the sealing plate 54. In addition, gaskets 90 are fitted to each of the terminal insertion holes 58 and 59 of the sealing plate 54 (see Figure 2). This prevents the positive electrode terminal 60 (or negative electrode terminal 65) inserted into the terminal insertion holes 58 and 59 from making electrical contact with the sealing plate 54. Furthermore, an internal insulating member 94 is placed between the positive electrode first current collector 71 (or negative electrode first current collector 76) and the inner surface of the sealing plate 54. The internal insulating member 94 includes a plate-shaped base portion 94a interposed between the positive electrode first current collector 71 (or negative electrode first current collector 76) and the inner surface of the sealing plate 54. This prevents the positive electrode first current collector 71 or the negative electrode first current collector 76 from making electrical contact with the sealing plate 54. Furthermore, the internal insulating member 94 includes a protruding portion 94b that protrudes from the inner surface of the sealing plate 54 toward the electrode body 40 (see Figures 2 and 3). This restricts the movement of the electrode body 40 in the height direction Z and prevents the electrode body 40 from making direct contact with the sealing plate 54. In addition, the multiple electrode bodies 40 are housed inside the battery case 50 covered by an electrode body holder 98 (see Figure 3) made of an insulating resin sheet. This prevents the electrode body 40 from making direct contact with the outer casing 52. The material of each of the insulating members described above is not particularly limited as long as it has the required insulating properties. As an example, synthetic resin materials such as polyolefin resins (e.g., polypropylene (PP), polyethylene (PE)) and fluororesins (e.g., perfluoroalkoxyalkanes (PFA), polytetrafluoroethylene (PTFE)) can be used.

[0024] (6) Electrode body Next, the electrode body 40 according to this embodiment will be described. As shown in Figure 7, the electrode body 40 according to this embodiment comprises a strip-shaped first separator 30A, a strip-shaped first electrode plate (positive electrode plate 10), a strip-shaped second separator 30B, and a strip-shaped second electrode plate (negative electrode plate 20). Hereinafter, the four strip-shaped members constituting the electrode body 40 will also be referred to as "sheet members". The electrode body 40 according to this embodiment is a wound body (wound electrode body) in which the positive electrode plate 10 and the negative electrode plate 20 are wound around the first separator 30A and the second separator 30B. As shown in Figures 7 to 9, the electrode body 40 according to this embodiment is flattened as a whole.

[0025] Furthermore, as shown in Figure 9, the flattened electrode body 40 has a pair of curved portions 40r with curved outer surfaces and a flat portion 40f with a flat outer surface that connects the pair of curved portions 40r. In this energy storage device 100, the electrode body 40 is housed in the battery case 50 such that the winding axis WL of the electrode body 40 and the width direction Y of the energy storage device 100 are approximately the same (see Figure 2). That is, the "winding axis direction" in the following description is approximately the same direction as the width direction Y in the figure. Also, the "winding direction" in the following description refers to the direction from the end to the beginning of the sheet member (first separator 30A, positive electrode plate 10, second separator 30B, negative electrode plate 20) along the winding of the sheet member. As shown in Figure 3, in this embodiment, three electrode bodies 40 are housed inside the battery case 50. However, the number of electrode bodies housed in a single battery case is not particularly limited; it may be two or more (multiple), or it may be just one.

[0026] (a) Positive plate As shown in Figure 7, the positive electrode plate 10 (first electrode plate) is a long, strip-shaped member. The positive electrode plate 10 comprises a positive electrode core 12, which is a strip-shaped metal foil, and a positive electrode active material layer 14 applied to at least one surface of the positive electrode core 12. From the viewpoint of battery performance, it is preferable that the positive electrode active material layer 14 is applied to both sides of the positive electrode core 12. In this positive electrode plate 10, a positive electrode tab 12t protrudes outward (to the left in Figure 7) from one end edge in the winding axis direction (width direction Y). Multiple positive electrode tabs 12t are formed at predetermined intervals along the longitudinal direction L of the long, strip-shaped positive electrode plate 10. These positive electrode tabs 12t are regions where the positive electrode active material layer 14 is not applied, and the positive electrode core 12 is exposed. Furthermore, a protective layer 16 is formed in the region adjacent to the end edge of the positive electrode plate 10 on the positive electrode tab 12t side, extending along the longitudinal direction of the positive electrode plate 10.

[0027] Each component constituting the positive electrode plate 10 can be made of conventionally known materials that can be used in general energy storage devices (e.g., lithium-ion secondary batteries) without any particular limitations. For example, a metallic material having a predetermined conductivity can preferably be used for the positive electrode core 12. Such a positive electrode core 12 is preferably made of, for example, aluminum or an aluminum alloy. On the other hand, the positive electrode active material layer 14 is a layer containing positive electrode active material. The material of the positive electrode active material layer 14 will be described below using a lithium-ion secondary battery as an example. However, the following description is not intended to limit the positive electrode plate of the electrode body disclosed herein.

[0028] The positive electrode active material for lithium-ion secondary batteries is a particulate material capable of reversibly intercepting and releasing lithium ions (charge carriers). From the viewpoint of stably producing a high-performance positive electrode plate 10, lithium transition metal composite oxides are preferred as the positive electrode active material. Among the above lithium transition metal composite oxides, lithium transition metal composite oxides containing at least one of the group consisting of nickel (Ni), cobalt (Co), and manganese (Mn) as the transition metal are particularly preferred. Specific examples include lithium nickel cobalt manganese composite oxide (NCM), lithium nickel composite oxide, lithium cobalt composite oxide, lithium manganese composite oxide, lithium nickel manganese composite oxide, lithium nickel cobalt aluminum composite oxide (NCA), and lithium iron nickel manganese composite oxide. Furthermore, a preferred example of a lithium transition metal composite oxide that does not contain Ni, Co, and Mn is lithium iron phosphate composite oxide (LFP). In this specification, "lithium nickel cobalt manganese-based composite oxide" is a term that encompasses oxides containing additive elements in addition to the main constituent elements (Li, Ni, Co, Mn, O). Examples of such additive elements include transition metal elements and main group metal elements such as Mg, Ca, Al, Ti, V, Cr, Si, Y, Zr, Nb, Mo, Hf, Ta, W, Na, Fe, Zn, and Sn. The additive elements may also be metalloid elements such as B, C, Si, and P, or nonmetallic elements such as S, F, Cl, Br, and I. While a detailed explanation is omitted, this also applies to other lithium transition metal composite oxides described as "~-based composite oxide." Furthermore, the positive electrode active material layer 14 may contain additives other than the positive electrode active material. Examples of such additives include conductive materials and binders. Specific examples of conductive materials include carbon materials such as acetylene black (AB). Specific examples of binders include resin binders such as polyvinylidene fluoride (PVdF). The content of the positive electrode active material when the total solid content of the positive electrode active material layer 14 is taken as 100% by mass is generally 80% by mass or more, and is typically 90% by mass or more.

[0029] On the other hand, the protective layer 16 is a layer configured to have lower electrical conductivity than the positive electrode active material layer 14. By providing such a protective layer 16 in a region adjacent to the edge of the positive electrode plate 10, it is possible to prevent internal short circuits caused by direct contact between the positive electrode core 12 and the negative electrode active material layer 24 when the separator is damaged. For example, it is preferable to form a layer containing insulating ceramic particles as the protective layer 16. Examples of such ceramic particles include inorganic oxides such as alumina (Al2O3), magnesia (MgO), silica (SiO2), and titania (TiO2), nitrides such as aluminum nitride and silicon nitride, metal hydroxides such as calcium hydroxide, magnesium hydroxide, and aluminum hydroxide, clay minerals such as mica, talc, boehmite, zeolite, apatite, and kaolin, and glass fibers. Considering insulating properties and heat resistance, alumina, boehmite, aluminum hydroxide, silica, and titania are preferred among the above. Furthermore, the protective layer 16 may contain a binder for fixing the ceramic particles to the surface of the positive electrode core 12. Examples of such binders include resin binders such as polyvinylidene fluoride (PVdF). Note that the protective layer is not an essential component of the positive electrode plate. In other words, the energy storage device disclosed herein can also use a positive electrode plate without a protective layer.

[0030] (b) Negative electrode plate As shown in Figure 7, the negative electrode plate 20 (second electrode plate) is a long, strip-shaped member. This negative electrode plate 20 comprises a negative electrode core 22, which is a strip-shaped metal foil, and a negative electrode active material layer 24 applied to the surface of the negative electrode core 22. From the viewpoint of battery performance, it is preferable that the negative electrode active material layer 24 is applied to both sides of the negative electrode core 22. Furthermore, the negative electrode plate 20 is provided with negative electrode tabs 22t that protrude outward (to the right in Figure 7) from one end in the winding axis direction (width direction Y). Multiple negative electrode tabs 22t are provided at predetermined intervals along the longitudinal direction L of the negative electrode plate 20. These negative electrode tabs 22t are regions where the negative electrode active material layer 24 is not applied, and the negative electrode core 22 is exposed.

[0031] Each component constituting the negative electrode plate 20 can be made of conventionally known materials that can be used in general energy storage devices (e.g., lithium-ion secondary batteries) without any particular limitations. For example, a metallic material having a predetermined conductivity can preferably be used for the negative electrode core 22. Such a negative electrode core 22 is preferably made of, for example, copper or a copper alloy. On the other hand, the negative electrode active material layer 24 is a layer containing negative electrode active material. The material of the negative electrode active material layer 24 will be described below using a lithium-ion secondary battery as an example. However, the following description is not intended to limit the negative electrode plate of the electrode body disclosed herein.

[0032] The negative electrode active material is a material that can reversibly absorb and release charge carriers in relation to the positive electrode active material described above. The specific material of the negative electrode active material is not particularly limited, and any material that can be used in conventional general energy storage devices can be used without particular restriction. Examples of such negative electrode active materials include carbon materials and silicon-based materials. Examples of carbon materials include graphite, hard carbon, soft carbon, and amorphous carbon. Amorphous carbon-coated graphite, where the surface of graphite is coated with amorphous carbon, can also be used. On the other hand, examples of silicon-based materials include silicon and silicon oxide (silica). Furthermore, silicon-based materials may contain other metallic elements (e.g., alkaline earth metals) or their oxides. The negative electrode active material layer 24 may also contain additives other than the negative electrode active material. Examples of such additives include binders and thickeners. Specific examples of binders include rubber-based binders such as styrene-butadiene rubber (SBR). Specific examples of thickeners include carboxymethylcellulose (CMC). Furthermore, the content of the negative electrode active material when the total solid content of the negative electrode active material layer 24 is taken as 100% by mass is generally 30% by mass or more, and typically 50% by mass or more. The negative electrode active material may account for 80% by mass or more, or even 90% by mass or more, of the negative electrode active material layer 24.

[0033] (c) Separator As shown in Figure 7, the electrode body 40 according to this embodiment comprises two separators (first separator 30A and second separator 30B). Each separator is an insulating sheet with multiple fine through-holes through which a charge carrier can pass. By interposing the first separator 30A and the second separator 30B between the positive electrode plate 10 and the negative electrode plate 20, contact between the positive electrode plate 10 and the negative electrode plate 20 is prevented, and the charge carrier (e.g., lithium ions) can be moved between the positive electrode plate 10 and the negative electrode plate 20. The material of the separator can be any material that can be used for separators in conventionally known energy storage devices without particular limitations. For example, the separator is preferably a porous sheet-like member containing a polyolefin resin or the like. This ensures sufficient flexibility of the separator and facilitates the fabrication (winding and press molding) of the electrode body 40. Polyethylene (PE), polypropylene (PP), and mixtures thereof can be used as the polyolefin resin.

[0034] Furthermore, as will be described in more detail later, in the technology disclosed herein, the electrode body 40 is disassembled by gripping and pulling the first separator 30A and / or the second separator 30B. For this reason, it is preferable to use separators that have a certain level of strength or more. From this viewpoint, the thickness of each separator is preferably 5 μm or more, more preferably 8 μm or more, even more preferably 10 μm or more, and particularly preferably 12 μm or more. On the other hand, the thickness of the separator is preferably 30 μm or less, more preferably 25 μm or less, even more preferably 20 μm or less, and particularly preferably 18 μm or less. As a result, the distance between the positive electrode plate 10 and the negative electrode plate 20 (inter-electrode distance) is shortened, making it possible to construct an energy storage device 100 with excellent charge and discharge efficiency.

[0035] Next, the first separator 30A and the second separator 30B will be described separately. As shown in Figure 10, a first adhesive layer 34A is applied to the surface of the first separator 30A facing the positive electrode plate 10 (the rear Rr side surface in Figure 10). This allows the first separator 30A to be bonded to the positive electrode plate 10 (first electrode plate). On the other hand, no adhesive layer is applied to the surface of the first separator 30A facing the negative electrode plate 20 (the front F side surface in Figure 10). Therefore, the first separator 30A is not bonded to the negative electrode plate 20 (second electrode plate). Next, a second adhesive layer 34B is applied to the surface of the second separator 30B facing the negative electrode plate 20 (the rear Rr side surface in Figure 10). This allows the second separator 30B to be bonded to the negative electrode plate 20 (second electrode plate). Furthermore, no adhesive layer is applied to the surface of the second separator 30B facing the positive electrode plate 10 (the front F side in Figure 10). Therefore, the second separator 30B is not bonded to the positive electrode plate 10 (first electrode plate).

[0036] The first adhesive layer 34A and the second adhesive layer 34B (hereinafter collectively referred to as the "adhesive layer") are layers containing at least a binder resin. Examples of this binder resin include polyvinylidene fluoride (PVdF), acrylic resin, and styrene-butadiene rubber (SBR). This allows for suitable bonding between the electrode plate and the separator. Furthermore, the adhesive layer of the electrode body disclosed herein may contain inorganic particles. This imparts heat resistance to the adhesive layer, suppressing thermal shrinkage of the separator when the temperature rises, thereby contributing to improved safety of the energy storage device. Examples of inorganic particles include ceramic particles mainly composed of ceramics such as alumina, silica, titania, boehmite, aluminum hydroxide, magnesium carbonate, magnesia, zirconia, zinc oxide, iron oxide, ceria, and yttria. The binder resin content in the adhesive layer is preferably 10% by mass or more, more preferably 15% by mass or more, and particularly preferably 20% by mass or more. This allows for more favorable adhesion between the electrode plate and the separator. On the other hand, if the adhesive layer becomes too tacky, it may become difficult to manufacture the electrode body (winding each sheet member). From this viewpoint, the binder resin content in the adhesive layer is preferably 40% by mass or less, more preferably 35% by mass or less, and particularly preferably 30% by mass or less. Note that the "binder resin content" above is the mass ratio of the binder resin to the total mass of the adhesive layer.

[0037] (d) Wound structure The following describes the specific winding structure of the electrode body 40 according to this embodiment. First, as shown in Figure 9, when manufacturing the electrode body 40, the first separator 30A, the positive electrode plate 10, the second separator 30B, and the negative electrode plate 20 are wound with their respective ends aligned. As a result, inside the electrode body 40, the starting end of the first separator 30A (first starting end 30As), the starting end of the positive electrode plate 10 (positive starting end 10s), the starting end of the second separator 30B (second starting end 30Bs), and the starting end of the negative electrode plate 20 (negative starting end 20s) are all arranged in a state where they are roughly aligned. However, in the technology disclosed herein, the position of the starting end of each sheet member is not particularly limited. For example, even if the starting positions of each sheet member are different, the effects of the technology disclosed herein (separation of the positive electrode plate 10 and the negative electrode plate 20) can be appropriately achieved.

[0038] On the other hand, in the electrode body 40 according to this embodiment, the positions of the ends of each winding of the sheet member are different. First, the length of the negative electrode plate 20 in this embodiment is set to be longer than that of the positive electrode plate 10. Therefore, as shown near the upper curved portion 40r in Figure 9, the outermost negative electrode plate 20 is wound so as to cover the end of the winding of the positive electrode plate 10 (positive electrode end portion 10e). Then, a region that does not face the positive electrode plate 10 is formed near the end of the winding of the negative electrode plate 20 (negative electrode end portion 20e). As a result, the area of ​​the negative electrode plate 20 becomes larger than the area of ​​the positive electrode plate 10.

[0039] Next, the lengths of the first separator 30A and the second separator 30B are set to be longer than the length of the pair of electrode plates (positive electrode plate 10 and negative electrode plate 20). Therefore, as shown in Figure 9, the first separator 30A extends from the positive electrode end portion 10e and is wound around the outer circumference of the electrode body 40. On the other hand, the second separator 30B extends from the negative electrode end portion 20e and is wound around the outer circumference of the electrode body 40. That is, as shown in Figures 9 and 10, a separator winding portion 40s is formed on the outer circumference of the electrode body 40 (winding body) according to this embodiment, in which only the first separator 30A and the second separator 30B are wound. This protects the positive electrode plate 10 and the negative electrode plate 20 from external impacts, etc. Note that the number of turns of the first separator 30A and the second separator 30B in the separator winding portion 40s is not particularly limited.

[0040] In the electrode body 40 according to this embodiment, the first separator 30A is wound around the outermost circumference of the wound body. As shown in Figure 8, the winding end of the second separator 30B (second end portion 30Be) extends downward D from the winding end of the first separator 30A (first end portion 30Ae) and is exposed on the outer surface of the wound body (electrode body 40). Therefore, in the electrode body 40 according to this embodiment, both the first end portion 30Ae and the second end portion 30Be can be seen from the outside. This makes it easy to grasp both the first end portion 30Ae of the first separator 30A and the second end portion 30Be of the second separator 30B when disassembling the electrode body 40.

[0041] Here, as shown in Figure 10, in this embodiment, no adhesive layer (first adhesive layer 34A, second adhesive layer 34B) is applied to the first separator 30A and the second separator 30B in the separator winding portion 40s. That is, the separator winding portion 40s in this embodiment has a non-adhesive region 30X where the first separator 30A and the second separator 30B are not bonded. This non-adhesive region 30X is formed in the first opposing portion F1 between the inner surface 30Aa of the first separator 30A and the outer surface 30Bb of the second separator 30B. The non-adhesive region 30X is also formed in the second opposing portion F2 between the outer surface 30Ab of the first separator 30A and the inner surface 30Ba of the second separator 30B. In other words, in this embodiment, the first separator 30A has a first adhesive layer 34A applied to the region facing the positive electrode plate 10. However, the region of the first separator 30A that is wound around the separator winding portion 40s (the region from the first end portion 30Ae to the positive electrode end portion 10e) does not have an adhesive layer applied to it (see Figure 11). Similarly, the second separator 30B has a second adhesive layer 34B applied to the region facing the negative electrode plate 20. However, the region of the second separator 30B that is wound around the separator winding portion 40s (the region from the second end portion 30Be to the negative electrode end portion 20e) does not have an adhesive layer applied to it (see Figure 11). With this configuration, the electrode body 40 allows the separator winding portion 40s to be easily unwound simply by gripping and pulling the first terminal portion 30Ae and the second terminal portion 30Be.

[0042] Next, as shown in Figures 8 to 10, in this embodiment, the first adhesive tape 80 is attached to the outermost surface of the electrode body 40 (winding body) so as to straddle both the first end portion 30Ae and the second end portion 30Be. This prevents the electrode body 40 from disassembling during manufacturing or use. In addition, the circumferential end of the first adhesive tape 80 in this embodiment has a first release portion 82 that does not adhere to the outermost surface of the winding body (electrode body 40). By grasping this first release portion 82 and pulling the first adhesive tape 80, the first adhesive tape 80 can be easily peeled off while suppressing damage to the separator. This prevents damage to the first end portion 30Ae and the second end portion 30Be when peeling off the first adhesive tape 80. As a result, the first end portion 30Ae and the second end portion 30Be can be properly grasped when unwinding the separator winding portion 40s. In this specification, the "release portion of the adhesive tape" does not need to adhere to the outermost surface of the electrode body, and various configurations can be adopted. For example, the release portion can be formed by not applying adhesive to the end of the adhesive tape. Alternatively, if adhesive is applied to the entire surface of one side of the adhesive tape, the end of the adhesive tape may be folded so that the adhesive surfaces face each other. Even when such a configuration is adopted, an adhesive tape having a release portion can be formed.

[0043] Furthermore, in this embodiment, the first peel-off portion 82 is provided at the end of the first adhesive tape 80 that is closer to the first end portion 30Ae (upper U in Figure 8) in the circumferential direction (height direction Z in Figure 8). With this configuration, the first adhesive tape 80 can be peeled off without going against the winding direction of the separator (from upper U to lower D in Figure 8). This further effectively suppresses damage to the first end portion 30Ae and the second end portion 30Be. However, this configuration is not limited to the technology disclosed herein. By appropriately adjusting the tackiness of the first adhesive tape 80 and the strength of the separator, damage to the first end portion 30Ae and the second end portion 30Be can be sufficiently suppressed even when the first peel-off portion is provided at the end that is closer to the second end portion 30Be (lower D in Figure 8).

[0044] 2. Disassembly of the electrode body When recovering valuable metals from the energy storage device 100 with the above configuration, the energy storage device 100 is disassembled and the electrode body 40 is removed. Then, the electrode body 40 is disassembled to separate the positive electrode plate 10 and the negative electrode plate 20. This allows the positive electrode plate 10 and the negative electrode plate 20 to be provided for recycling processing individually, which contributes to the efficiency of the recovery rate of valuable metals and the reduction of recycling costs. The procedure for separating the positive electrode plate 10 and the negative electrode plate 20 from the energy storage device 100 with the above configuration will be described below.

[0045] First, when disassembling the energy storage device 100, it is advisable to discharge the battery and cut the battery case 50. This allows for the safe disassembly of the charged energy storage device 100 (battery case 50). Then, the electrode body 40 is removed from the disassembled battery case 50. At this time, as shown in Figure 5, the positive electrode tab group 42 of the electrode body 40 is connected to the positive electrode second current collector 72. Therefore, it is advisable to cut either the positive electrode tab group 42 or the positive electrode second current collector 72. Also, the negative electrode tab group 44 is connected to the negative electrode second current collector 77. Therefore, it is advisable to cut either the negative electrode tab group 44 or the negative electrode second current collector 77. This allows for easy removal of the electrode body 40. Note that the procedure for removing the electrode body 40 from the battery case 50 is not particularly limited and can be appropriately modified according to the structure of the energy storage device 100.

[0046] Next, in this embodiment, the electrode body 40 is disassembled to separate the positive electrode plate 10 and the negative electrode plate 20. Specifically, first, the first adhesive tape 80 is peeled off from the electrode body 40. At this time, by grasping and pulling the first peeling portion 82, the first adhesive tape 80 can be easily peeled off while suppressing damage to the first separator 30A and the second separator 30B. Next, the first end portion 30Ae of the first separator 30A and the second end portion 30Be of the second separator 30B are grasped and pulled separately. At this time, in the separator winding portion 40s in this embodiment, the opposing surfaces of the first separator 30A and the second separator 30B are not adhered to each other. (In other words, a non-adhesive region 30X is provided in each of the first opposing portion F1 and the second opposing portion F2 in Figure 10.) Therefore, the separator winding portion 40s can be easily unwound simply by pulling on each of the first end portion 30Ae and the second end portion 30Be.

[0047] In this embodiment, the first separator 30A and the positive electrode plate 10 are bonded together, and the second separator 30B and the negative electrode plate 20 are bonded together. However, the first separator 30A and the negative electrode plate 20 are not bonded together, and the second separator 30B and the positive electrode plate 10 are not bonded together. Therefore, when the winding of the separator winding portion 40s is undone, the electrode body 40 can be separated into the positive electrode plate 10 bonded to the first separator 30A and the negative electrode plate 20 bonded to the second separator 30B, as shown in Figure 11.

[0048] In this embodiment, it is preferable to individually calcine the positive electrode plate 10 and the negative electrode plate 20 after separation. This removes the first separator 30A and the second separator 30B. As a result, the positive electrode plate 10 and the negative electrode plate 20 can be recovered in a separated state. Then, by dissolving the calcined positive electrode plate 10 in a predetermined dissolving solution (such as an acid solution), a metal solution containing only the metal components derived from the positive electrode plate 10 can be prepared. Valuable metals (such as Li, Ni, Co, and Mn) that can be used in the manufacture of the positive electrode plate 10 can be easily extracted from this metal solution. On the other hand, by dissolving the calcined negative electrode plate 20 in a dissolving solution, a metal solution containing only the metal components derived from the negative electrode plate 20 can be prepared. Valuable metals (such as Cu) that can be used in the manufacture of the negative electrode plate 20 can be easily extracted from this metal solution. As described above, according to this embodiment, since a pair of electrode plates can be provided for regeneration processing individually, it is possible to contribute to the efficiency of the recovery rate of valuable metals and the reduction of regeneration costs.

[0049] <Other Embodiments> The above describes one embodiment of the technology disclosed herein. The first embodiment described above is merely an example of how the technology disclosed herein can be applied and does not limit the scope of the technology disclosed herein. Other embodiments of the technology disclosed herein will now be described.

[0050] 1. Bonding of the electrode plate to the separator In the first embodiment, a positive electrode plate 10 is used as the electrode plate (first electrode plate) bonded to the first separator 30A, and a negative electrode plate 20 is used as the electrode plate (second electrode plate) bonded to the second separator 30B. However, the stacking order of the electrode plates is not a limiting factor to the technology disclosed herein. For example, the negative electrode plate may be bonded to the first separator (i.e., the separator wound around the outermost periphery of the wound body). In this case, the positive electrode plate is bonded to the second separator (the separator wound relatively inward). The technology disclosed herein can be applied to electrode bodies with such configurations as well.

[0051] 2. Specific bonding methods Furthermore, in the first embodiment, an adhesive layer is applied to each of the first separator 30A and the second separator 30B. However, the means for bonding the separator and the electrode plate are not particularly limited. For example, as described above, the positive electrode active material layer 14 and the negative electrode active material layer 24 contain a binder. By unevenly distributing this binder on the surface of the positive electrode active material layer 14 and the negative electrode active material layer 24, an electrode plate with excellent surface adhesion can be obtained. Alternatively, a strip-shaped adhesive sheet may be inserted between the separator and the electrode plate. By using these means, the separator and the electrode plate can be bonded without applying an adhesive layer to the surface of the separator.

[0052] 3. Area to form a non-adhesive zone As shown in Figure 10, in the first embodiment, non-adhesive regions 30X are formed on both the first opposing portion F1 and the second opposing portion F2. In other words, in the first embodiment, the first separator 30A and the second separator 30B are not bonded to each other in the separator winding portion 40s. However, the non-adhesive region only needs to be formed on at least one of the first opposing portion and the second opposing portion, and is not limited to the first embodiment described above. For example, in the embodiment shown in Figure 12, the first opposing portion F1 is provided with a first adhesive layer 34A, and the second opposing portion F2 is not provided with an adhesive layer. In other words, in Figure 12, the non-adhesive region 30X is formed only on the second opposing portion F2. With such a configuration, the electrode body 40 can unwind the separator winding portion 40s along the second opposing portion F2 which has the non-adhesive region 30X, while the first opposing portion F1 remains bonded. In this case, as shown in Figure 13, after disassembling the electrode body 40, a laminate 40X is formed at one end in the longitudinal direction (the right side in Figure 13) having an adhesive residue 30re to which the first separator 30A and the second separator 30B are bonded via the first adhesive layer 34A. By cutting off this adhesive residue 30re, the positive electrode plate 10 bonded to the first separator 30A and the negative electrode plate 20 bonded to the second separator 30B can be separated. As described above, even if a non-adhesive region is formed in either the first opposing portion or the second opposing portion, the pair of electrode plates can be properly separated.

[0053] Furthermore, in the first embodiment, the non-adhesive region is formed over the entire area of ​​the separator winding in the winding direction. In other words, in the first embodiment, the first separator 30A does not have the first adhesive layer 34A applied to the region from the first end portion 30Ae to the positive electrode end portion 10e. Similarly, in the first embodiment, the second separator 30B does not have the second adhesive layer 34B applied to the region from the second end portion 30Be to the negative electrode end portion 20e. However, the non-adhesive region in the art disclosed herein only needs to extend inward in the winding direction from the first end portion of the first separator and / or the second end portion of the second separator. If a non-adhesive region is formed at the end portion of the separator in this way, the end portion can be grasped when unwinding the separator winding. In this case, even if there is a region where the separators are bonded together inward in the winding direction from the end portion, the bond between the separators can be separated by grasping and pulling the end portion. As described above, if a non-adherent region is formed extending inward in the winding direction from the first end portion and / or the second end portion, the pair of electrode plates can be properly separated even if there is bond between separators in other regions.

[0054] Preferably, the non-adhesive region extends 10 mm or more (more preferably 15 mm or more, particularly preferably 20 mm or more) in the winding direction from the first end of the first separator (or the second end of the second separator). This allows the first end of the first separator (or the second end of the second separator) to be easily grasped. Furthermore, it is more preferable that the non-adhesive region is formed in an area of ​​1% or more (more preferably 2% or more, particularly preferably 3% or more) of the total length of the first opposing portion (or the second opposing portion) in the winding direction. This allows the separator winding to be unwound even more easily. On the other hand, there is no particular upper limit to the length of the non-adhesive region in the winding direction. As in the first embodiment, when the non-adhesive region is formed over the entire area (100%) of the first opposing portion (or the second opposing portion) in the winding direction, the separator winding can be unwound particularly easily.

[0055] 4. Composition of non-adhesive areas Furthermore, in the first embodiment, a non-adhesive region is formed by providing a region on the separator where the adhesive layer is not applied. However, the non-adhesive region is not limited to the configuration of the first embodiment, as long as it can achieve a state in which the first separator and the second separator are not adhered to each other. For example, when using a separator on which the adhesive layer is applied over the entire length, a non-adhesive resin sheet may be attached to the region where the non-adhesive region is to be formed. Even when such a configuration is adopted, a non-adhesive region can be formed in a predetermined region extending from the end portion.

[0056] 5. Adhesive tape Furthermore, in the first embodiment, the first adhesive tape 80 is attached to the outer circumferential surface of the electrode body 40. However, in the technology disclosed herein, in order to further facilitate the disassembly of the electrode body 40, an adhesive tape other than the first adhesive tape 80 may be attached. For example, as shown in Figure 14, if a non-adhesive area is provided in the region including the first end portion 30Ae (first opposing portion), a second adhesive tape 80A that straddles the first end portion 30Ae but does not straddle the second end portion 30Be may be attached to the outermost surface of the winding body. In this case, when the second adhesive tape 80A is peeled off along the winding direction (from the bottom D to the top U in Figure 14), the first end portion 30Ae is pulled along with the peeling off of the second adhesive tape 80A. This makes it easy to unwind the separator winding along the first opposing portion. Furthermore, it is preferable that the second adhesive tape 80A has a second release portion 82A formed at one of its ends in the circumferential direction (height direction Z in Figure 14), specifically at the end facing the second separator 30B (the lower end D in Figure 14), which does not adhere to the outermost surface of the winding body. This makes it easier to peel off the second adhesive tape 80A along the winding direction (from the lower end D to the upper end U in Figure 14).

[0057] Furthermore, as shown in Figure 15, if a non-adhesive area is provided in the region including the second end portion 30Be (second opposing portion), it is preferable that a third adhesive tape 80B that straddles the second end portion 30Be but does not straddle the first end portion 30Ae is attached to the outermost surface of the winding body. In this case, when the third adhesive tape 80B is peeled off along the winding direction (from the lower D to the upper U in Figure 14), the second end portion 30Be is pulled along with the peeling of the third adhesive tape 80B. This makes it easy to unwind the separator winding along the second opposing portion. It is preferable that the end of the third adhesive tape 80B facing the first separator 30A (the lower D end in Figure 14) has a third release portion 82B that does not adhere to the outermost surface of the winding body. This makes it easier to peel off the third adhesive tape 80B from the lower D to the upper U.

[0058] Furthermore, if non-adhesive areas are provided in both the region including the first terminal portion 30Ae (first opposing portion) and the region including the second terminal portion 30Be (second opposing portion), it is preferable to apply both the second adhesive tape 80A and the third adhesive tape 80B, as shown in Figure 16. This makes it easier to unwind the separator winding along each of the first and second opposing portions, thereby making it easier to separate the positive electrode plate and the negative electrode plate.

[0059] Furthermore, the second and third adhesive tapes may be integrated with the first adhesive tape. Specifically, in the configuration shown in Figure 17, the first adhesive tape 80 is attached so as to straddle both the first end portion 30Ae and the second end portion 30Be. A first release portion 82 is formed at the upper end of the first adhesive tape 80 (the end on the first end portion 30Ae side). In addition, perforations 84 are formed on the first adhesive tape 80 that straddle the second end portion 30Be but surround the area that does not straddle the first end portion 30Ae. A third release portion 82B is formed at the lower end of the area surrounded by the perforations 84 (the end facing the first separator 30A). When unwinding the electrode body 40 with this configuration, first, grasp the first release portion 82 and peel off the first adhesive tape 80 from the top U downward D. At this time, the first adhesive tape 80 breaks along the perforations 84. As a result, a third adhesive tape 80B is formed on the surface of the electrode body 40 after the first adhesive tape 80 has been peeled off, straddling the second end portion 30Be but not straddling the first end portion 30Ae. Then, by grasping the third peel portion 82B and peeling off the third adhesive tape 80B upward U, the winding of the separator winding portion in the region including the second end portion 30Be (second opposing portion) can be easily undone.

[0060] The technologies disclosed herein have been described in detail above, but these are merely illustrative examples and do not limit the scope of the claims. The technologies described in the claims include various modifications and changes to the specific examples illustrated above. In other words, the technologies disclosed herein encompass the forms described in items 1 to 8 below.

[0061] <Item 1> A strip-shaped first electrode plate, A strip-shaped first separator, A strip-shaped second electrode plate, A strip-shaped second separator and Equipped with, A wound body in which the first electrode plate and the second electrode plate are wound around each other via the first separator and the second separator, The first separator is bonded to the first electrode plate and not bonded to the second electrode plate. The second separator is bonded to the second electrode plate, but not to the first electrode plate. A separator winding section is formed on the outer circumference of the winding body, in which only the first separator and the second separator are wound, and the first separator is wound around the outermost circumference of the separator winding section. The second end portion, which is the winding end of the second separator, extends from the first end portion, which is the winding end of the first separator, and is exposed on the outer surface of the winding body. The separator winding portion has a first opposing portion between the inner surface of the first separator and the outer surface of the second separator, and at least one of the second opposing portions between the outer surface of the first separator and the inner surface of the second separator has a non-adherent region where the first separator and the second separator are not adhered. The non-adhesive region extends inward in the winding direction from the first end and / or the second end, An electrode body wherein a first adhesive tape spanning both the first and second end portions is attached to the outermost surface of the winding body, and a first release portion is formed on at least one of the ends of the first adhesive tape in the circumferential direction, which does not adhere to the outermost surface of the winding body.

[0062] <Item 2> The electrode body according to item 1, wherein the first peeling portion is formed at the end adjacent to the first terminal portion.

[0063] <Item 3> The non-adhesive region is provided in the region including the first terminal portion. The electrode body according to item 1 or 2, wherein a second adhesive tape that straddles the first end portion but does not straddle the second end portion is attached to the outermost surface of the wound body.

[0064] <Item 4> The electrode body according to item 3, wherein a second release portion is formed at the end of the second adhesive tape in the circumferential direction that faces the second separator, and the end of the second adhesive tape does not adhere to the outermost surface of the wound body.

[0065] <Item 5> The non-adhesive region is provided in the region including the second terminal portion. An electrode body according to any one of items 1 to 4, wherein a third adhesive tape that straddles the second end portion but does not straddle the first end portion is attached to the outermost surface of the wound body.

[0066] <Item 6> The electrode body according to item 5, wherein a third release portion is formed at the end of the third adhesive tape in the circumferential direction that faces the first separator, and the end of the third adhesive tape does not adhere to the outermost surface of the wound body.

[0067] <Item 7> The electrode body according to any one of items 1 to 6, wherein the non-adhesive region is formed on both the first opposing portion and the second opposing portion, extending over the entire area of ​​the separator winding portion.

[0068] <Item 8> Electrode body and A battery case housing the electrode body and Equipped with, The electrode body is an electrode body described in any one of items 1 to 7, and is used as an energy storage device. [Explanation of Symbols]

[0069] 10 Positive plate 10e Positive terminal end 10s Positive electrode starting end 20 Negative electrode plates 20e Negative terminal end 20s Negative electrode start end 30A First Separator 30Ae 1st end 30As 1st starting end 30B Second Separator 30Be 2nd end 30Bs 2nd starting end 30X non-adhesive area 30re adhesive residue 34A 1st adhesive layer 34B 2nd adhesive layer 40 Electrode body 40X laminate 40s Separator winding section 50 Battery Case 80 First Adhesive Tape 80A 2nd Adhesive Tape 80B Third Adhesive Tape 82 First peeling section 82A Second peeling section 82B Third peeling section 84 perforations 100 Energy Storage Devices F1 First Opposite Section F2 Second Opposite Section

Claims

1. A strip-shaped first electrode plate, A strip-shaped first separator, A strip-shaped second electrode plate, A strip-shaped second separator and Equipped with, The first electrode plate and the second electrode plate are wound together via the first separator and the second separator, The first separator is bonded to the first electrode plate by applying a first adhesive layer to the surface facing the first electrode plate, and is not bonded to the second electrode plate. The first separator extends from the first electrode end portion, which is the winding end of the first electrode plate. The second separator is bonded to the second electrode plate by applying a second adhesive layer to the surface facing the second electrode plate, and is not bonded to the first electrode plate. The second separator extends from the second electrode end portion, which is the winding end of the second electrode plate. A separator winding section is formed on the outer circumference of the winding body, in which only the first separator and the second separator are wound, and the first separator is wound around the outermost circumference of the separator winding section. The second end portion, which is the winding end of the second separator, extends from the first end portion, which is the winding end of the first separator, and is exposed on the outer surface of the winding body. The separator winding portion has a first opposing portion between the inner surface of the first separator and the outer surface of the second separator, and at least one of the second opposing portions between the outer surface of the first separator and the inner surface of the second separator has a non-adherent region where the first separator and the second separator are not adhered. The non-adhesive region extends inward in the winding direction from the first end and / or the second end, A first adhesive tape spanning both the first and second end portions is attached to the outermost surface of the winding body, and a first release portion is formed on at least one of the ends of the first adhesive tape in the circumferential direction, which does not adhere to the outermost surface of the winding body. The first separator does not have a first adhesive layer applied to the region from the first terminal portion to the first electrode terminal portion. The second separator is an electrode body in which the second adhesive layer is not applied to the region from the second terminal portion to the second electrode terminal portion.

2. The electrode body according to claim 1, wherein the first peeling portion is formed at the end adjacent to the first terminal portion.

3. The non-adhesive region is provided in the region including the first terminal portion. The electrode body according to claim 1, wherein a second adhesive tape that straddles the first end portion but does not straddle the second end portion is attached to the outermost surface of the wound body.

4. The electrode body according to claim 3, wherein a second release portion is formed at the end of the second adhesive tape in the circumferential direction that faces the second separator, and the end of the second adhesive tape does not adhere to the outermost surface of the wound body.

5. The non-adhesive region is provided in the region including the second terminal portion. The electrode body according to claim 1, wherein a third adhesive tape that straddles the second end portion but does not straddle the first end portion is attached to the outermost surface of the wound body.

6. The electrode body according to claim 5, wherein a third release portion is formed at the end of the third adhesive tape in the circumferential direction that faces the first separator, and the end of the third adhesive tape does not adhere to the outermost surface of the wound body.

7. The electrode body according to any one of claims 1 to 6, wherein the non-adhesive region is formed in both the first opposing portion and the second opposing portion, extending over the entire area of ​​the separator winding portion.

8. Electrode body and A battery case housing the electrode body Equipped with, The electrode body is the electrode body described in claim 1, wherein the device is an energy storage device.

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