Energy storage element

Abstract

To provide an energy storage element that can be miniaturized or have increased capacity. [Solution] An energy storage element 10 comprising a first electrode body 600 and a second electrode body 700, comprising one or more first sheet members 810 positioned on the outer surface of the first electrode body 600 and including the space between the first electrode body 600 and the second electrode body 700, one or more second sheet members 820 positioned on the outer surface of the second electrode body 700 and including the space between the first electrode body 600 and the second electrode body 700, or one or more third sheet members 830 positioned on the outer surface of the first electrode body 600 and the second electrode body 700 spanning both the first electrode body 600 and the second electrode body 700, wherein at least one first sheet member 810 is positioned between the first electrode body 600 and the second electrode body 700 in a position that does not overlap with any of the second sheet members 820, or on the side of the first electrode body 600 opposite to the second electrode body 700 in a position that does not overlap with any of the third sheet members 830.

Description

Technical Field

[0001] The present invention relates to a power storage element including an electrode body on which a sheet member is disposed on an outer surface.

Background Art

[0002] Conventionally, in a power storage element including an electrode body, a configuration in which a sheet member is disposed on an outer surface of the electrode body is known. For example, in Patent Document 1, an electrode laminate (electrode body) used in a power storage element has a substantially rectangular parallelepiped shape in which a plurality of electrodes are laminated, and is fixed by a fixing member (sheet member) along the lamination direction from the upper surface to the lower surface. The configuration is disclosed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the above conventional power storage element, it may not be possible to achieve miniaturization or high capacity. That is, when the power storage element includes a plurality of electrode bodies and a plurality of sheet members are disposed on the plurality of electrode bodies, the plurality of sheet members overlap, so that the size of the electrode body including the sheet members becomes large, and there is a risk of increasing the size of the power storage element or reducing the capacity. In such a case, it is not possible to achieve miniaturization or high capacity of the power storage element.

[0005] The present invention has been made by the inventors of the present application newly paying attention to the above problems, and an object thereof is to provide a power storage element capable of achieving miniaturization or high capacity.

Means for Solving the Problems

[0006] To achieve the above objective, an energy storage element according to one aspect of the present invention is an energy storage element comprising a first electrode body and a second electrode body, comprising: one or more first sheet members disposed on the outer surface of the first electrode body and at a position including the space between the first electrode body and the second electrode body; one or more second sheet members disposed on the outer surface of the second electrode body and at a position including the space between the first electrode body and the second electrode body; or one or more third sheet members disposed on the outer surfaces of the first electrode body and the second electrode body extending across the first electrode body and the second electrode body, wherein at least one of the first sheet members is disposed between the first electrode body and the second electrode body at a position that does not overlap with any of the second sheet members, or on the surface of the first electrode body opposite to the second electrode body at a position that does not overlap with any of the third sheet members.

[0007] According to this, in the energy storage element, at least one first sheet member is positioned on the outer surface of the first electrode body, between the first and second electrode bodies, in a position that does not overlap with any of the second sheet members, or on the side of the first electrode body opposite the second electrode body, in a position that does not overlap with any of the third sheet members. In this way, when the first sheet member and the second or third sheet members are arranged on the outer surface of one or both of the first and second electrode bodies, at least one first sheet member is positioned in a position that does not overlap with any of the second or third sheet members. This suppresses overlap between the first sheet member and the second or third sheet members. Therefore, it is possible to suppress an increase in the size of the electrode body including the sheet members, and to miniaturize or increase the capacity of the energy storage element.

[0008] The energy storage element may include one or more second sheet members, and all of the first sheet members may be positioned between the first electrode body and the second electrode body in a location that does not overlap with any of the second sheet members.

[0009] According to this, in a configuration in which the energy storage element includes a second sheet member, the overlap between the first and second sheet members can be further suppressed by positioning all the first sheet members in a location where they do not overlap with any of the second sheet members. Therefore, the size of the electrode body, including the sheet members, can be further suppressed, and the energy storage element can be made smaller or have a higher capacity.

[0010] The energy storage element may include one or more third sheet members, and all of the first sheet members may be positioned on the side of the first electrode body opposite to the second electrode body, in a location that does not overlap with any of the third sheet members.

[0011] According to this, in a configuration in which the energy storage element includes a third sheet member, the overlap between the first and third sheet members can be further suppressed by positioning all the first sheet members in a location where they do not overlap with any of the third sheet members. Therefore, the size of the electrode body, including the sheet members, can be further suppressed, and the energy storage element can be made smaller or have a higher capacity.

[0012] The energy storage element comprises one or more second sheet members and one or more third sheet members, and at least one of the second sheet members may be positioned on the side of the second electrode body opposite to the first electrode body, in a position that does not overlap with any of the third sheet members.

[0013] According to this, in a configuration in which the energy storage element comprises a second sheet member and a third sheet member, overlapping of the second and third sheet members can be suppressed by positioning at least one second sheet member in a location that does not overlap with any of the third sheet members. Therefore, the size of the electrode body, including the sheet members, can be suppressed, and the energy storage element can be made smaller or have a higher capacity.

[0014] All of the second sheet members may be positioned on the side of the second electrode body opposite to the first electrode body, in a location where they do not overlap with any of the third sheet members.

[0015] According to this method, by positioning all second sheet members in a location where they do not overlap with any third sheet members, the overlap between the second and third sheet members can be further suppressed. Therefore, the overall size of the electrode body, including the sheet members, can be further suppressed, enabling miniaturization or increased capacity of the energy storage element.

[0016] The energy storage element comprises one or more third sheet members, and at least one of the third sheet members may be positioned on a side of the first electrode body and the second electrode body that is different from all of the first sheet members.

[0017] According to this, in a configuration in which the energy storage element includes a third sheet member, by arranging the third sheet member on a different side from all of the first sheet members, it is easy to position the third sheet member in a location that does not overlap with any of the first sheet members. This makes it easy to realize a configuration that enables miniaturization or increased capacity of the energy storage element.

[0018] The present invention can be realized not only as such an energy storage element, but also as a combination of a first electrode body, a second electrode body, a first sheet member, and a second or third sheet member. [Effects of the Invention]

[0019] The energy storage element according to the present invention can be miniaturized or have its capacity increased. [Brief explanation of the drawing]

[0020] [Figure 1] This is a perspective view showing the external appearance of the energy storage element according to the embodiment. [Figure 2] This is an exploded perspective view showing the individual components of the energy storage element according to the embodiment, after disassembly. [Figure 3] This is a perspective view showing the configuration of the first electrode body and the second electrode body according to the embodiment. [Figure 4]It is a perspective view showing a configuration in which a first sheet member and a second sheet member are arranged on a first electrode body and a second electrode body according to an embodiment. [Figure 5] It is a front view showing a configuration in which a first sheet member and a second sheet member are arranged on a first electrode body and a second electrode body according to an embodiment. [Figure 6] It is a perspective view showing a configuration in which a third sheet member is arranged on a first electrode body and a second electrode body according to an embodiment. [Figure 7] It is a top view, a front view, and a bottom view showing a configuration when a first electrode body on which a first sheet member is arranged and a second electrode body on which a second sheet member is arranged are overlapped. [Figure 8] It is a top view, a front view, and a bottom view showing a configuration in which a third sheet member is arranged on a first electrode body and a second electrode body according to an embodiment. [Figure 9A] It is a perspective view showing a configuration when a second sheet member is not arranged on a first electrode body and a second electrode body according to a modification example of an embodiment. [Figure 9B] It is a perspective view showing a configuration when a second sheet member is not arranged on a first electrode body and a second electrode body according to another modification example of an embodiment.

Embodiments for Carrying Out the Invention

[0021] Hereinafter, a power storage element according to an embodiment (including its modification examples) of the present invention will be described with reference to the drawings. All of the embodiments described below show comprehensive or specific examples. The numerical values, shapes, materials, components, arrangement positions and connection forms of the components, manufacturing processes, the order of manufacturing processes, etc. shown in the following embodiments are examples and are not intended to limit the present invention. In each figure, dimensions and the like are not shown precisely. In each figure, the same or similar components are denoted by the same reference numerals.

[0022] In the following description and drawings, the direction in which the pair of electrode terminals (positive and negative sides, hereinafter the same) of the energy storage element are aligned, the direction in which the pair of current collectors are aligned, the width direction of the first electrode and the second electrode, or the opposing direction of the short sides of the container is defined as the X-axis direction. The direction in which the first electrode and the second electrode are aligned, the direction in which the electrode plates of the first and second electrode are stacked, the thickness direction of the first and second electrode, the opposing direction of the long sides of the container, or the thickness direction of the container is defined as the Y-axis direction. The direction in which the winding axis of the first electrode and the winding axis of the second electrode extend, the height direction of the first and second electrode, the direction in which the electrode terminals, current collectors, first electrode and second electrode, the direction in which the container body and lid of the container are aligned, or the up and down direction is defined as the Z-axis direction. These X-axis, Y-axis, and Z-axis directions intersect each other (orthogonal in this embodiment). Note that depending on the usage, the Z-axis direction may not be vertical; however, for the sake of explanation, the Z-axis direction will be described as vertical.

[0023] In the following explanation, for example, the X-axis positive direction refers to the direction of the X-axis arrow, and the X-axis negative direction refers to the opposite direction. The same applies to the Y-axis and Z-axis directions. Furthermore, expressions indicating relative directions or orientations, such as parallel and orthogonal, include cases where they are not strictly those directions or orientations. For example, two directions being orthogonal does not only mean that the two directions are perfectly orthogonal, but also that they are substantially orthogonal, that is, they may include a difference of, for example, a few percent.

[0024] (Embodiment) [1. General description of the energy storage element 10] First, a general description of the energy storage element 10 in this embodiment will be given. Figure 1 is a perspective view showing the external appearance of the energy storage element 10 according to this embodiment. Figure 2 is an exploded perspective view showing the individual components of the energy storage element 10 according to this embodiment.

[0025] The energy storage element 10 is a secondary battery (single cell) capable of charging and discharging electricity, and specifically, is a non-aqueous electrolyte secondary battery such as a lithium-ion secondary battery. The energy storage element 10 is used for power storage or power supply purposes. The energy storage element 10 is used, for example, as a battery for driving or starting the engine of mobile vehicles such as automobiles, motorcycles, watercraft, ships, snowmobiles, agricultural machinery, construction machinery, or railway vehicles for electric railways. Examples of automobiles include electric vehicles (EVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and gasoline automobiles. Examples of railway vehicles for electric railways include electric trains, monorails, maglev trains, and hybrid trains equipped with both diesel engines and electric motors. The energy storage element 10 can also be used as a stationary battery for household or commercial use.

[0026] Furthermore, the energy storage element 10 is not limited to a non-aqueous electrolyte secondary battery, but may be a secondary battery other than a non-aqueous electrolyte secondary battery, or a capacitor. The energy storage element 10 may not be a secondary battery, but a primary battery that allows the user to use the stored electricity without charging. The energy storage element 10 may be a battery using a solid electrolyte. The energy storage element 10 may be a pouch-type energy storage element. In this embodiment, the energy storage element 10 is shown in a flat rectangular parallelepiped shape (square), but the shape of the energy storage element 10 is not limited to a rectangular parallelepiped shape, but may be cylindrical, oval cylindrical, or a polygonal prism shape other than a rectangular parallelepiped.

[0027] As shown in Figure 1, the energy storage element 10 comprises a container 100, a pair of electrode terminals 200 (positive and negative sides), and a pair of upper gaskets 300 (positive and negative sides). As shown in Figure 2, the container 100 houses a pair of lower gaskets 400 (positive and negative sides), a pair of current collectors 500 (positive and negative sides), a first electrode body 600 and a second electrode body 700, and a first sheet member 810, a second sheet member 820, and a third sheet member 830. An electrolyte (non-aqueous electrolyte) is sealed inside the container 100, but it is not shown in the illustration. There are no particular restrictions on the type of electrolyte, as long as it does not impair the performance of the energy storage element 10, and various types can be selected. In addition to the above components, spacers may be placed to the side or below the first electrode body 600 and the second electrode body 700, and insulating films may be placed to enclose the first electrode body 600 and the second electrode body 700, etc.

[0028] The container 100 is a rectangular parallelepiped (square or box-shaped) case having a container body 110 with an opening formed therein and a lid 120 that closes the opening of the container body 110. The container body 110 is a rectangular cylindrical member with a bottom that constitutes the main body of the container 100. The container body 110 has a pair of flat, rectangular long sidewalls 111 on both sides (long sides) in the Y-axis direction, a pair of flat, rectangular short sidewalls 112 on both sides (short sides) in the X-axis direction, and a flat, rectangular bottom wall 113 on the Z-axis negative side. The lid 120 is a rectangular plate-shaped member that constitutes the lid of the container 100 and is arranged extending in the X-axis direction in the Z-axis positive direction of the container body 110. The lid 120 is provided with a gas discharge valve 121 that releases pressure when the pressure inside the container 100 rises excessively, and an injection section 122 for injecting electrolyte into the container 100, etc.

[0029] With this configuration, the container 100 is sealed inside the container body 110 by joining the container body 110 and the lid 120 by welding or the like after housing the first electrode body 600 and the second electrode body 700 inside the container body 110. The material of the container 100 (container body 110 and lid 120) is not particularly limited and can be made of weldable metals such as stainless steel, aluminum, aluminum alloy, iron, or plated steel sheet, but resin can also be used.

[0030] The first electrode body 600 and the second electrode body 700 are energy storage elements (power generation elements) that can store electricity, each comprising a positive electrode plate, a negative electrode plate, and a separator. Specifically, the first electrode body 600 and the second electrode body 700 are so-called horizontally wound electrode bodies that are oval-shaped when viewed from the Z-axis direction, formed by winding layers of material arranged so that a separator is sandwiched between the positive electrode plate and the negative electrode plate. Thus, the first electrode body 600 and the second electrode body 700 have similar configurations.

[0031] Specifically, in the first electrode body 600, multiple tabs of the positive electrode plate are stacked to form a positive-side tab bundle 620, and multiple tabs of the negative electrode plate are stacked to form a negative-side tab bundle 630. In other words, the first electrode body 600 has an electrode body main body 610 and tab bundles 620 and 630 that protrude in the positive Z-axis direction from a part of the electrode body main body 610. Similarly, in the second electrode body 700, multiple tabs of the positive electrode plate are stacked to form a positive-side tab bundle 720, and multiple tabs of the negative electrode plate are stacked to form a negative-side tab bundle 730. In other words, the second electrode body 700 has an electrode body main body 710 and tab bundles 720 and 730 that protrude in the positive Z-axis direction from a part of the electrode body main body 710. A detailed explanation of the configurations of the first electrode body 600 and the second electrode body 700 will be given later.

[0032] The first sheet member 810, the second sheet member 820, and the third sheet member 830 are sheet-like members that are placed on the outer surface of at least one of the electrode bodies, the first electrode body 600 and the second electrode body 700. In this embodiment, the first sheet member 810 is an insulating tape that is placed (attached) to the outer surface of the first electrode body 600 and fixes (bundles) the positive electrode plate, negative electrode plate, and separator of the first electrode body 600 by sandwiching them in the Y-axis direction. The second sheet member 820 is an insulating tape that is placed (attached) to the outer surface of the second electrode body 700 and fixes (bundles) the positive electrode plate, negative electrode plate, and separator of the second electrode body 700 by sandwiching them in the Y-axis direction. The third sheet member 830 is an insulating tape that is placed (attached) to the outer surfaces of both the first electrode body 600 and the second electrode body 700 and fixes (bundles) the first electrode body 600 and the second electrode body 700 by sandwiching them in the Y-axis direction.

[0033] The first sheet member 810, the second sheet member 820, and the third sheet member 830 are formed from electrically insulating resins such as polypropylene (PP), polyethylene (PE), polystyrene (PS), polyphenylene sulfide resin (PPS), polyphenylene ether (PPE (including modified PPE)), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyetherether ketone (PEEK), tetrafluoroethylene perfluoroalkyl vinyl ether (PFA), polytetrafluoroethylene (PTFE), polyethersulfone (PES), ABS resin, or composite materials thereof. The first sheet member 810, the second sheet member 820, and the third sheet member 830 may be formed from any material; for example, they may be made from conductive materials as long as the electrical insulation of the first electrode body 600 and the second electrode body 700 is ensured. A detailed explanation of the configuration of the first sheet member 810, the second sheet member 820, and the third sheet member 830 will be given later.

[0034] The electrode terminals 200 are terminal members (positive and negative terminals) that are electrically connected to the first electrode body 600 and the second electrode body 700 via the current collector 500. In other words, the electrode terminals 200 are metallic members that lead the electricity stored in the first electrode body 600 and the second electrode body 700 to the external space of the energy storage element 10, and also introduce electricity into the internal space of the energy storage element 10 in order to store electricity in the first electrode body 600 and the second electrode body 700. The electrode terminals 200 are made of a conductive material such as aluminum, aluminum alloy, copper, or copper alloy. The electrode terminals 200 are connected (joined) to the current collector 500 by crimping or the like, and are attached to the cover body 120.

[0035] Specifically, the electrode terminal 200 has a shaft portion 201 (rivet portion) that extends downward (in the negative Z-axis direction). The shaft portion 201 is then inserted into the through hole 301 of the upper gasket 300, the through hole 123 of the cover 120, the through hole 401 of the lower gasket 400, and the through hole 501 of the current collector 500, and crimped. In this way, the electrode terminal 200 is fixed to the cover 120 together with the upper gasket 300, the lower gasket 400, and the current collector 500. Note that the method of connecting (joining) the electrode terminal 200 and the current collector 500 is not limited to crimping, and welding methods such as ultrasonic welding, laser welding or resistance welding, or mechanical joining other than crimping, such as screw fastening, may also be used.

[0036] The current collector 500 is a flat, rectangular current collector (positive electrode current collector and negative electrode current collector) that electrically connects the first electrode body 600 and the second electrode body 700 to the electrode terminal 200. Specifically, the positive electrode current collector 500 is connected (joined) to the tab bundles 620 and 720 on the positive electrode side of the first electrode body 600 and the second electrode body 700 by welding or the like, and is also joined to the electrode terminal 200 on the positive electrode side by crimping or the like, as described above. The negative electrode current collector 500 is connected (joined) to the tab bundles 630 and 730 on the negative electrode side of the first electrode body 600 and the second electrode body 700 by welding or the like, and is also joined to the electrode terminal 200 on the negative electrode side by crimping or the like, as described above. The material of the current collector 500 is not particularly limited, but for example, the current collector 500 on the positive electrode side is made of a conductive material such as aluminum or an aluminum alloy, and the current collector 500 on the negative electrode side is made of a conductive material such as copper or a copper alloy. The method of connecting (joining) the current collector 500 to the tab bundles 620 and 720 or tab bundles 630 and 730 can be any welding method such as ultrasonic welding, laser welding or resistance welding, or mechanical joining such as crimping or screw fastening.

[0037] The upper gasket 300 is a flat, electrically insulating sealing member positioned between the lid 120 of the container 100 and the electrode terminal 200. The lower gasket 400 is a flat, electrically insulating sealing member positioned between the lid 120 and the current collector 500. The upper gasket 300 and the lower gasket 400 are formed from an electrically insulating resin or the like, for example, a resin that can be used for the first sheet member 810, etc.

[0038] [2. Description of the configuration of the first electrode body 600 and the second electrode body 700] Next, the configurations of the first electrode body 600 and the second electrode body 700 will be described in detail. Figure 3 is a perspective view showing the configurations of the first electrode body 600 and the second electrode body 700 according to this embodiment. Since the first electrode body 600 and the second electrode body 700 have similar configurations, Figure 3 shows the configurations of the first electrode body 600 and the second electrode body 700 using the same figure. Specifically, Figure 3(a) shows the configuration of the first electrode body 600 (or the second electrode body 700) in a partially unwound state, and Figure 3(b) shows the configuration of the first electrode body 600 (or the second electrode body 700) after winding.

[0039] As described above, the first electrode body 600 and the second electrode body 700 have similar configurations. Therefore, the following description will focus on the configuration of the first electrode body 600, and the description of the configuration of the second electrode body 700 will be simplified or omitted. As shown in Figure 3(a), the first electrode body 600 is formed by alternately stacking and winding a positive electrode plate 640, a negative electrode plate 650, and separators 661 and 662. In other words, the first electrode body 600 is formed by stacking and winding the positive electrode plate 640, separator 661, negative electrode plate 650, and separator 662 in this order.

[0040] The positive electrode plate 640 is an electrode plate in which a positive electrode active material layer is formed on the surface of a positive electrode base layer, which is a long, strip-shaped metal foil made of aluminum or an aluminum alloy. The negative electrode plate 650 is an electrode plate in which a negative electrode active material layer is formed on the surface of a negative electrode base layer, which is a long, strip-shaped metal foil made of copper or a copper alloy. As the positive electrode base layer and the negative electrode base layer, any known material that is stable against oxidation-reduction reactions during charging and discharging can be used, such as nickel, iron, stainless steel, titanium, calcined carbon, conductive polymer, conductive glass, and Al-Cd alloy. As the positive electrode active material used in the positive electrode active material layer and the negative electrode active material used in the negative electrode active material layer, any known material that is capable of intercalating and deintercalating lithium ions can be used.

[0041] For example, as positive electrode active materials, polyanionic compounds such as LiMPO4, LiMSiO4, LiMBO3 (where M is one or more transition metal elements selected from Fe, Ni, Mn, Co, etc.), lithium titanate, LiMn2O4, and LiMn 1.5 Ni 0.5 Spinel-type lithium manganese oxides such as O4, lithium transition metal oxides such as LiMO2 (where M is one or more transition metal elements selected from Fe, Ni, Mn, Co, etc.) can be used. As negative electrode active materials, lithium metals, lithium alloys (lithium-silicon, lithium-aluminum, lithium-lead, lithium-tin, lithium-aluminum-tin, lithium-gallium, and lithium metal-containing alloys such as Wood's alloys), alloys capable of intercalating and deintercalating lithium, carbon materials (e.g., graphite, non-graphitizable carbon, easily graphitizable carbon, low-temperature calcined carbon, amorphous carbon, etc.), silicon oxides, metal oxides, lithium metal oxides (Li4Ti5O 12 Examples include polyphosphate compounds, or compounds of transition metals and group 14 to 16 elements, such as Co3O4 and Fe2P, which are generally called conversion negative electrodes.

[0042] Separators 661 and 662 are microporous sheets made of resin. Any known material can be used for separators 661 and 662, as long as it does not impair the performance of the energy storage element 10. For example, separators 661 and 662 can be woven fabrics, nonwoven fabrics, or synthetic resin microporous membranes made of polyolefin resins such as polyethylene, which are insoluble in organic solvents.

[0043] The positive electrode plate 640 has a plurality of rectangular tabs 641 protruding in the positive Z-axis direction at its end in the positive Z-axis direction, and the plurality of tabs 641 are arranged in a stacked state in the Y-axis direction. Similarly, the negative electrode plate 650 has a plurality of rectangular tabs 651 protruding in the positive Z-axis direction at its end in the positive Z-axis direction, and the plurality of tabs 651 are arranged in a stacked state in the Y-axis direction. Tabs 641 and 651 are portions where the active material layer is not formed and the base material layer is exposed. The shape of tabs 641 and 651 is not particularly limited.

[0044] Then, as shown in Figure 3(b), the stacked tabs 641 are bundled together to form a tab bundle 620 that extends in a state protruding in the Z-axis positive direction. Similarly, the stacked tabs 651 are bundled together to form a tab bundle 630 that extends in a state protruding in the Z-axis positive direction. These tab bundles 620 and 630 are joined, for example, to the Y-axis positive surface of the current collector 500 which is facing the current collector 500 in the Y-axis direction, and then bent in the Y-axis positive direction together with the current collector 500.

[0045] The electrode body portion 610 is the part that constitutes the main body of the first electrode body 600, and specifically, it is the part of the first electrode body 600 other than the tab bundles 620 and 630. In other words, the electrode body portion 610 is an elongated cylindrical or oval-shaped portion formed by winding the active material layers of the positive electrode plate 640 and the negative electrode plate 650 with the separators 661 and 662. As a result, the electrode body portion 610 has a pair of electrode body flat portions 611 and 612 on both sides in the Y-axis direction, and a pair of electrode body curved portions 613 and 614 on both sides in the X-axis direction.

[0046] The electrode body flat portion 611 is a flat and rectangular portion that connects a pair of electrode body curved portions 613 and 614, extending parallel to the XZ plane oriented in the negative Y-axis direction, and is positioned opposite the long side wall portion 111 of the container body 110 in the negative Y-axis direction. The electrode body flat portion 612 is a flat and rectangular portion that connects a pair of electrode body curved portions 613 and 614, extending parallel to the XZ plane oriented in the positive Y-axis direction, and is positioned opposite the second electrode body 700. The electrode body curved portion 613 is a curved portion that curves in a semicircular arc shape so as to project in the negative X-axis direction when viewed from the Z-axis direction, and extends in the Z-axis direction, and is positioned opposite the short side wall portion 112 of the container body 110 in the negative X-axis direction. The electrode body curved portion 614 is curved in a semicircular arc shape so as to protrude in the positive X-axis direction when viewed from the Z-axis direction, and is a curved portion that extends in the Z-axis direction, and is positioned opposite the short side wall portion 112 of the container body 110 in the positive X-axis direction.

[0047] Similarly, the second electrode body 700 also has a positive electrode plate 740, a negative electrode plate 750, and separators 761 and 762. The positive electrode plate 740 has a tab 741, and the negative electrode plate 750 has a tab 751. Multiple tabs 741 are bundled together to form a tab bundle 720, and multiple tabs 751 are bundled together to form a tab bundle 730. The electrode body portion 710 of the second electrode body 700 has a pair of electrode body flat portions 711 and 712 on both sides in the Y-axis direction, and a pair of electrode body curved portions 713 and 714 on both sides in the X-axis direction.

[0048] [3. Description of the first sheet member 810, the second sheet member 820, and the third sheet member 830] Next, the configurations of the first sheet member 810, the second sheet member 820, and the third sheet member 830 will be described in detail. Figure 4 is a perspective view showing the configuration in which the first sheet member 810 and the second sheet member 820 are arranged on the first electrode body 600 and the second electrode body 700 according to this embodiment. Specifically, Figure 4(a) is a perspective view showing the configuration in which the first sheet member 810 is arranged on the first electrode body 600, and Figure 4(b) is a perspective view showing the configuration in which the second sheet member 820 is arranged on the second electrode body 700. Figure 5 is a front view showing the configuration in which the first sheet member 810 and the second sheet member 820 are arranged on the first electrode body 600 and the second electrode body 700 according to this embodiment. Specifically, Figure 5(a) is a front view showing the configuration in which the first sheet member 810 is arranged on the first electrode body 600, and Figure 5(b) is a front view showing the configuration in which the second sheet member 820 is arranged on the second electrode body 700.

[0049] Figure 6 is a perspective view showing a configuration in which a third sheet member 830 is placed on the first electrode body 600 and the second electrode body 700 according to this embodiment. Specifically, Figure 6(a) is a perspective view showing a configuration in which the first electrode body 600 on which the first sheet member 810 is placed and the second electrode body 700 on which the second sheet member 820 is placed are superimposed. Figure 6(b) is a perspective view showing a configuration in which the third sheet member 830 is placed on the first electrode body 600 and the second electrode body 700 shown in Figure 6(a). Figure 7 is a top view, front view, and bottom view showing a configuration in which the first electrode body 600 on which the first sheet member 810 is placed and the second electrode body 700 on which the second sheet member 820 is placed are superimposed according to this embodiment. Specifically, Figure 7 shows a top view, front view, and bottom view of the configuration shown in Figure 6(a), where Figure 7(a) is a top view, Figure 7(b) is a front view, and Figure 7(c) is a bottom view. Figure 8 is a top view, front view, and bottom view showing a configuration in which a third sheet member 830 is arranged on the first electrode body 600 and the second electrode body 700 according to this embodiment. Specifically, Figure 8 shows a top view, front view, and bottom view of the configuration shown in Figure 6(b), where Figure 8(a) is a top view, Figure 8(b) is a front view, and Figure 8(c) is a bottom view.

[0050] [3.1 Description of the structure of the first sheet member 810] As shown in Figures 4(a) and 5(a), one or more first sheet members 810 are arranged on the outer surface of the first electrode body 600 and at a position that includes the space between the first electrode body 600 and the second electrode body 700. Specifically, multiple first sheet members 810 are arranged on the outer surface of the first electrode body 600 on the side opposite to the second electrode body 700 (the Y-axis negative direction side), the Z-axis direction side, and the space between the first electrode body 600 and the second electrode body 700 (the Y-axis positive direction side). In this embodiment, three first sheet members 810 (811-813) are arranged at the Z-axis positive end of the electrode body main body 610 of the first electrode body 600, and three first sheet members 810 (814-816) are arranged at the Z-axis negative end of the electrode body main body 610. More specifically, the six first sheet members 810 (811-816) are attached to the electrode body flat portions 611 and 612 of the electrode body main body portion 610 so as to sandwich them from the Y-axis direction.

[0051] These six first sheet members 810 (811-816) fix (bundle) the positive electrode plate 640, negative electrode plate 650, and separators 661 and 662 of the first electrode body 600 in a stacked state in the Y-axis direction. Each first sheet member 810 is positioned on both sides of the first electrode body 600 in the Y-axis direction and on the Z-axis direction, so that the first electrode body 600 can be fixed by sandwiching it in the Y-axis direction, thereby more securely fixing the positive electrode plate 640, negative electrode plate 650, and separators 661 and 662.

[0052] The first sheet member 811 is positioned (attached) between the tab bundles 620 and 630 of the first electrode body 600, near the tab bundle 630. The first sheet member 811 extends from the Y-axis negative direction surface of the first electrode body 600 (the surface opposite to the second electrode body 700), through the Z-axis positive direction surface of the first electrode body 600, to the Y-axis positive direction surface of the first electrode body 600 (the surface on the second electrode body 700 side). In other words, the first sheet member 811 is attached to the Z-axis positive end and X-axis central part of the electrode body flat portions 611 and 612, extending from the outer surface of electrode body flat portion 611 to the outer surface of electrode body flat portion 612.

[0053] The first sheet member 812 is positioned (attached) to the tab bundle 620 of the first electrode body 600 in the negative X-axis direction, close to the tab bundle 620. Similar to the first sheet member 811, the first sheet member 812 is positioned from the negative Y-axis direction surface of the first electrode body 600, through the positive Z-axis direction surface, to the positive Y-axis direction surface. In other words, the first sheet member 812 is positioned attached to the ends of the electrode body flat portions 611 and 612 in the positive Z-axis direction and negative X-axis direction, extending from the outer surface of the electrode body flat portion 611 to the outer surface of the electrode body flat portion 612. In the X-axis direction, the first sheet member 812 is narrower than the first sheet member 811, and in the Z-axis direction, it has the same length as the first sheet member 811.

[0054] The first sheet member 813 is positioned (attached) to the tab bundle 630 of the first electrode body 600 in the positive X-axis direction, close to the tab bundle 630. Similar to the first sheet member 811, the first sheet member 813 is positioned from the negative Y-axis direction surface of the first electrode body 600, through the positive Z-axis direction surface, to the positive Y-axis direction surface. In other words, the first sheet member 813 is positioned attached to the ends of the electrode body flat portions 611 and 612 in the positive Z-axis and positive X-axis directions, extending from the outer surface of the electrode body flat portion 611 to the outer surface of the electrode body flat portion 612. In the X-axis direction, the first sheet member 813 is narrower than the first sheet member 811 and has the same width as the first sheet member 812, and in the Z-axis direction, it has the same length as the first sheet members 811 and 812.

[0055] The first sheet members 814 to 816 are each positioned opposite to the first sheet members 811 to 813 in the Z-axis direction (attached). The first sheet members 814 to 816 are positioned from the Y-axis negative direction surface of the first electrode body 600 (the surface opposite to the second electrode body 700), through the Z-axis negative direction surface of the first electrode body 600, to the Y-axis positive direction surface of the first electrode body 600 (the surface on the second electrode body 700 side). In other words, the first sheet members 814 to 816 are positioned attached to the Z-axis negative end and the X-axis central and both ends of the electrode body flat portions 611 and 612, extending from the outer surface of the electrode body flat portion 611 to the outer surface of the electrode body flat portion 612. In this embodiment, the first sheet members 814 to 816 each have a configuration obtained by rotating the first sheet members 811 to 813 by 180° around the Y axis. In other words, the first sheet members 815 and 816 have the same width as each other in the X-axis direction and are narrower than the first sheet member 814, and have the same length as the first sheet member 814 in the Z-axis direction.

[0056] [3.2 Explanation of the structure of the second sheet member 820 and its positional relationship with the first sheet member 810] As shown in Figures 4(b) and 5(b), one or more second sheet members 820 are arranged on the outer surface of the second electrode body 700, including the space between the first electrode body 600 and the second electrode body 700. Specifically, multiple second sheet members 820 are arranged on the outer surface of the second electrode body 700, on the space between the first electrode body 600 and the second electrode body 700 (the Y-axis negative direction surface), on the Z-axis direction surface, and on the surface opposite to the first electrode body 600 (the Y-axis positive direction surface). In this embodiment, three second sheet members 820 (821-823) are arranged at the Z-axis positive end of the electrode body portion 710 of the second electrode body 700, and three second sheet members 820 (824-826) are arranged at the Z-axis negative end of the electrode body portion 710. More specifically, the six second sheet members 820 (821-826) are attached to the electrode body flat portions 711 and 712 of the electrode body main body portion 710 so as to sandwich them from the Y-axis direction.

[0057] These six second sheet members 820 (821-826) fix (bundle) the positive electrode plate 740, negative electrode plate 750, and separators 761 and 762 of the second electrode body 700 in a stacked state in the Y-axis direction. Each second sheet member 820 is positioned on both sides of the second electrode body 700 in the Y-axis direction and on the Z-axis direction, allowing the second electrode body 700 to be fixed by being sandwiched in the Y-axis direction, thereby more securely fixing the positive electrode plate 740, negative electrode plate 750, and separators 761 and 762.

[0058] The second sheet member 821 is positioned (attached) between the tab bundles 720 and 730 of the second electrode body 700, closer to the tab bundle 720. The second sheet member 821 extends from the Y-axis negative direction surface of the second electrode body 700 (the surface on the first electrode body 600 side), through the Z-axis positive direction surface of the second electrode body 700, to the Y-axis positive direction surface of the second electrode body 700 (the surface opposite to the first electrode body 600). In other words, the second sheet member 821 is attached to the Z-axis positive end and X-axis central part of the electrode body flat portions 711 and 712, extending from the outer surface of electrode body flat portion 711 to the outer surface of electrode body flat portion 712.

[0059] The second sheet member 822 is positioned (attached) to the tab bundle 720 of the second electrode body 700 at a location far from the tab bundle 720 in the negative X-axis direction. Similar to the second sheet member 821, the second sheet member 822 is positioned from the negative Y-axis direction surface of the second electrode body 700, through the positive Z-axis direction surface, to the positive Y-axis direction surface. In other words, the second sheet member 822 is positioned at the positive Z-axis and negative X-axis ends of the electrode body flat portions 711 and 712, attached from the outer surface of the electrode body flat portion 711 to the outer surface of the electrode body flat portion 712. In the X-axis direction, the second sheet member 822 is narrower than the second sheet member 821, and in the Z-axis direction, it has the same length as the second sheet member 821.

[0060] The second sheet member 823 is positioned (attached) to the tab bundle 730 of the second electrode body 700 at a location far from the tab bundle 730 in the positive X-axis direction. Similar to the second sheet member 821, the second sheet member 823 is positioned from the negative Y-axis direction surface of the second electrode body 700, through the positive Z-axis direction surface, to the positive Y-axis direction surface. In other words, the second sheet member 823 is positioned attached to the ends of the electrode body flat portions 711 and 712 in the positive Z-axis and positive X-axis directions, extending from the outer surface of the electrode body flat portion 711 to the outer surface of the electrode body flat portion 712. In the X-axis direction, the second sheet member 823 is narrower than the second sheet member 821 and has the same width as the second sheet member 822, and in the Z-axis direction, it has the same length as the second sheet members 821 and 822.

[0061] The second sheet members 824 to 826 are each positioned opposite to the second sheet members 821 to 823 in the Z-axis direction (attached). The second sheet members 824 to 826 are positioned from the Y-axis negative direction surface of the second electrode body 700 (the surface on the first electrode body 600 side), through the Z-axis negative direction surface of the second electrode body 700, to the Y-axis positive direction surface of the second electrode body 700 (the surface opposite to the first electrode body 600). In other words, the second sheet members 824 to 826 are positioned attached to the Z-axis negative end and the X-axis central and both ends of the electrode body flat portions 711 and 712, extending from the outer surface of the electrode body flat portion 711 to the outer surface of the electrode body flat portion 712. In this embodiment, the second sheet members 824 to 826 each have a configuration obtained by rotating the second sheet members 821 to 823 by 180° around the Y axis. In other words, the second sheet members 825 and 826 have the same width as the second sheet member 824 in the X-axis direction, and are narrower than the second sheet member 824, and have the same length as the second sheet member 824 in the Z-axis direction. Furthermore, the second sheet members 821 to 826 each have the same shape and size as the first sheet members 811 to 816.

[0062] With the above configuration, as shown in Figure 5, the first sheet members 810 (811-816) are positioned differently from the second sheet members 820 (821-826) in the X-axis direction. Specifically, the first sheet members 811 and 814 are positioned in the positive X-axis direction more than the second sheet members 821 and 824. The first sheet members 812 and 815 are positioned in the positive X-axis direction more than the second sheet members 822 and 825. The first sheet members 813 and 816 are positioned in the negative X-axis direction more than the second sheet members 823 and 826.

[0063] As a result, as shown in Figures 6(a) and 7, even when the first electrode body 600 on which the first sheet member 810 is placed and the second electrode body 700 on which the second sheet member 820 is placed are superimposed in the Y-axis direction, the first sheet member 810 and the second sheet member 820 are positioned so as not to overlap. In other words, at least one first sheet member 810 is positioned so as not to overlap with any of the second sheet members 820 between the first electrode body 600 and the second electrode body 700. In this embodiment, all first sheet members 810 (811-816) are positioned so as not to overlap with any of the second sheet members 820 (821-826) between the first electrode body 600 and the second electrode body 700. In other words, the portions of the first sheet members 810 (811-816) facing the second electrode body 700 and the portions of the second sheet members 820 (821-826) facing the first electrode body 600 are positioned so as not to overlap in the Y-axis direction. In other words, the first sheet member 810 (811-816) and the second sheet member 820 (821-826) are positioned at different locations when viewed from the Y-axis direction.

[0064] [3.3 Explanation of the structure of the third sheet member 831 and its positional relationship with other sheet members] As shown in Figure 6(b) and Figure 8, one or more third sheet members 830 are arranged on the outer surfaces of the first electrode body 600 and the second electrode body 700, extending across the first electrode body 600 and the second electrode body 700. Specifically, multiple third sheet members 830 are arranged on the surface of the first electrode body 600 opposite to the second electrode body 700 (the surface in the negative Y-axis direction), on the surfaces of the first electrode body 600 and the second electrode body 700 in the Z-axis direction and the X-axis direction, and on the surface of the second electrode body 700 opposite to the first electrode body 600 (the surface in the positive Y-axis direction). In this embodiment, three third sheet members 830 (831-833) are arranged at the ends of the electrode body main portion 610 of the first electrode body 600 and the electrode body main portion 710 of the second electrode body 700 in the positive Z-axis direction. Three third sheet members 830 (834-836) are arranged at the Z-axis negative ends of the electrode body 610 and electrode body 710. Two third sheet members 830 (837 and 838) are arranged at both ends in the X-axis direction of the electrode body 610 and electrode body 710.

[0065] These eight third sheet members 830 (831-838) fix (bundle) the first electrode body 600 and the second electrode body 700 in an overlapping state in the Y-axis direction. Each third sheet member 830 is positioned on both sides of the Y-axis direction and on the Z-axis direction of the first electrode body 600 and the second electrode body 700, so that the first electrode body 600 and the second electrode body 700 can be fixed by being sandwiched in the Y-axis direction, thereby more securely fixing the first electrode body 600 and the second electrode body 700.

[0066] The third sheet member 831 is positioned (attached) between the first sheet member 811 and the second sheet member 821 in the X-axis direction. The third sheet member 831 extends from the Y-axis negative side of the first electrode body 600 (the side opposite to the second electrode body 700), through the Z-axis positive side of both the first electrode body 600 and the second electrode body 700, to the Y-axis positive side of the second electrode body 700 (the side opposite to the first electrode body 600). In other words, the third sheet member 831 is positioned in an attached state at the Z-axis positive end and X-axis central part of the electrode body main body 610 and the electrode body main body 710, extending from the outer surface of the electrode body flat portion 611 to the outer surface of the electrode body flat portion 712. In the X-axis direction, the third sheet member 831 has the same width as the first sheet member 811 and the second sheet member 821, and in the Z-axis direction, it is longer than the first sheet member 811 and the second sheet member 821.

[0067] The third sheet member 832 is positioned (attached) to the first sheet member 812 and the second sheet member 822 in the negative X-axis direction. Similar to the third sheet member 831, the third sheet member 832 is positioned from the negative Y-axis direction surface of the first electrode body 600, through the positive Z-axis direction surfaces of the first electrode body 600 and the second electrode body 700, to the positive Y-axis direction surface of the second electrode body 700. In other words, the third sheet member 832 is positioned attached to the ends of the electrode body main body portion 610 and the electrode body main body portion 710 in the positive Z-axis direction and negative X-axis direction, extending from the outer surface of the electrode body flat portion 611 to the outer surface of the electrode body flat portion 712. The third sheet member 832 has a smaller width than the third sheet member 831 in the X-axis direction and the same width as the first sheet member 812 and the second sheet member 822, and in the Z-axis direction it is shorter than the third sheet member 831 and the same length as the first sheet member 812 and the second sheet member 822.

[0068] The third sheet member 833 is positioned (attached) to the first sheet member 813 and the second sheet member 823 in the positive X-axis direction. Similar to the third sheet member 831, the third sheet member 833 is positioned from the negative Y-axis direction surface of the first electrode body 600, through the positive Z-axis direction surfaces of the first electrode body 600 and the second electrode body 700, to the positive Y-axis direction surface of the second electrode body 700. In other words, the third sheet member 833 is positioned attached to the ends of the electrode body main body portion 610 and the electrode body main body portion 710 in the positive Z-axis and positive X-axis directions, extending from the outer surface of the electrode body flat portion 611 to the outer surface of the electrode body flat portion 712. In the X-axis direction, the third sheet member 833 is narrower than the third sheet member 831 and has the same width as the third sheet member 832 (same width as the first sheet member 813 and the second sheet member 823), and in the Z-axis direction, it has the same length as the third sheet member 832.

[0069] The third sheet members 834 to 836 are each positioned opposite to the third sheet members 831 to 833 in the Z-axis direction (attached). The third sheet members 834 to 836 are positioned from the Y-axis negative direction surface of the first electrode body 600 (the surface opposite to the second electrode body 700), through the Z-axis positive direction surfaces of the first electrode body 600 and the second electrode body 700, to the Y-axis positive direction surface of the second electrode body 700 (the surface opposite to the first electrode body 600). In other words, the third sheet members 834 to 836 are positioned attached to the Z-axis negative end and the X-axis central and both ends of the electrode body main body 610 and the electrode body main body 710, extending from the outer surface of the electrode body flat portion 611 to the outer surface of the electrode body flat portion 712. In this embodiment, the third sheet members 834 to 836 are each formed by rotating the third sheet members 831 to 833 by 180° around the Y axis. That is, the third sheet members 835 and 836 have the same width as each other in the X-axis direction and are narrower than the third sheet member 834, and they have the same length as each other in the Z-axis direction and are shorter than the third sheet member 834.

[0070] The third sheet member 837 is positioned (attached) to the ends of the first electrode body 600 and the second electrode body 700 in the negative X-axis direction. The third sheet member 837 is positioned from the negative Y-axis direction surface of the first electrode body 600, through the negative X-axis direction surfaces of the first electrode body 600 and the second electrode body 700, to the positive Y-axis direction surface of the second electrode body 700. In other words, the third sheet member 837 is positioned in an attached state at the negative X-axis direction end and the center in the Z-axis direction of the electrode body main body portion 610 and the electrode body main body portion 710, extending from the outer surface of the electrode body flat portion 611 to the outer surface of the electrode body flat portion 712. Specifically, the third sheet member 837 is positioned in an attached state to the outer surfaces of the electrode body flat portion 611, through the outer surfaces of the electrode body curved portion 613 and the electrode body curved portion 713, to the outer surface of the electrode body flat portion 712. The third sheet member 837 is positioned between the first sheet member 812, the second sheet member 822, and the third sheet member 832, and the first sheet member 815, the second sheet member 825, and the third sheet member 835.

[0071] The third sheet member 838 is positioned (attached) to the X-axis positive ends of the first electrode body 600 and the second electrode body 700. The third sheet member 838 extends from the Y-axis negative surface of the first electrode body 600, through the X-axis positive surfaces of the first electrode body 600 and the second electrode body 700, to the Y-axis positive surface of the second electrode body 700. In other words, the third sheet member 838 is positioned in an attached state at the X-axis positive ends and Z-axis central parts of the electrode body main body portion 610 and electrode body main body portion 710, extending from the outer surface of the electrode body flat portion 611 to the outer surface of the electrode body flat portion 712. Specifically, the third sheet member 838 is positioned in an attached state to the outer surfaces of the electrode body flat portion 611, through the outer surfaces of the electrode body curved portion 614 and the electrode body curved portion 714, to the outer surface of the electrode body flat portion 712. The third sheet member 838 is positioned between the first sheet member 813, the second sheet member 823, and the third sheet member 833, and the first sheet member 816, the second sheet member 826, and the third sheet member 836. In this embodiment, the third sheet member 838 has a configuration in which the third sheet member 837 is rotated 180° around the Y axis.

[0072] Thus, at least one third sheet member 830 (837, 838) is positioned on a side of the first electrode body 600 and the second electrode body 700 that is different from all of the first sheet members 810 (811-816). Similarly, at least one third sheet member 830 (837, 838) is positioned on a side of the first electrode body 600 and the second electrode body 700 that is different from all of the second sheet members 820 (821-826).

[0073] With the above configuration, the third sheet members 830 (831-838) are positioned differently from the first sheet members 810 (811-816) and the second sheet members 820 (821-826). That is, at least one first sheet member 810 is positioned on the side of the first electrode body 600 opposite to the second electrode body 700, in a position that does not overlap with any of the third sheet members 830. At least one second sheet member 820 is positioned on the side of the second electrode body 700 opposite to the first electrode body 600, in a position that does not overlap with any of the third sheet members 830. In this embodiment, all of the first sheet members 810 (811-816) are positioned on the side of the first electrode body 600 opposite to the second electrode body 700, in a position that does not overlap with any of the third sheet members 830 (831-838). All second sheet members 820 (821-826) are positioned on the side of the second electrode body 700 opposite to the first electrode body 600, in a location where they do not overlap with any of the third sheet members 830 (831-838).

[0074] In other words, the portion of the first sheet member 810 (811-816) opposite to the second electrode body 700 and the portion of the third sheet member 830 (831-838) opposite to the second electrode body 700 are positioned so as not to overlap in the Y-axis direction. The portion of the second sheet member 820 (821-826) opposite to the first electrode body 600 and the portion of the third sheet member 830 (831-838) opposite to the first electrode body 600 are positioned so as not to overlap in the Y-axis direction. To put it another way, the first sheet member 810 (811-816), the second sheet member 820 (821-826), and the third sheet member 830 (831-838) are positioned in different locations when viewed from the Y-axis direction.

[0075] [4. Explanation of Effects] As described above, according to the energy storage element 10 of the present invention, at least one first sheet member 810 is positioned between the first electrode body 600 and the second electrode body 700 in a position that does not overlap with any of the second sheet members 820, or on the side of the first electrode body 600 opposite to the second electrode body 700 in a position that does not overlap with any of the third sheet members 830. In this way, when the first sheet member 810 and the second sheet member 820 or the third sheet member 830 are arranged on the outer surface of one or both of the first electrode body 600 and the second electrode body 700, at least one first sheet member 810 is positioned in a position that does not overlap with any of the second sheet members 820 or any of the third sheet members 830. This makes it possible to suppress overlap between the first sheet member 810 and the second sheet member 820 or the third sheet member 830. In this embodiment, it is possible to suppress overlap between the first sheet member 810 and both the second sheet member 820 and the third sheet member 830. Therefore, the size of the electrode body, including the sheet member, can be suppressed, and the energy storage element 10 can be made smaller or have a higher capacity. In addition, by arranging the first sheet member 810 and the second sheet member 820 or the third sheet member 830 on the outer surface of one or both of the first electrode body 600 and the second electrode body 700, plate displacement during transport and contamination (metal powder, etc.) can be suppressed in the first electrode body 600 and the second electrode body 700.

[0076] By positioning all the first sheet members 810 so that they do not overlap with any of the second sheet members 820, the overlap between the first sheet members 810 and the second sheet members 820 can be further suppressed. Therefore, the size of the electrode body, including the sheet members, can be further suppressed, and the energy storage element 10 can be made smaller or have a higher capacity.

[0077] By positioning all the first sheet members 810 so that they do not overlap with any of the third sheet members 830, the overlap between the first sheet members 810 and the third sheet members 830 can be further suppressed. Therefore, the size of the electrode body, including the sheet members, can be further suppressed, and the storage element 10 can be made smaller or have a higher capacity.

[0078] By positioning at least one second sheet member 820 in a location that does not overlap with any of the third sheet members 830, overlap between the second sheet members 820 and the third sheet members 830 can be suppressed. Therefore, the overall size of the electrode body, including the sheet members, can be kept from increasing, and the energy storage element 10 can be made smaller or have a higher capacity.

[0079] By positioning all the second sheet members 820 so that they do not overlap with any of the third sheet members 830, the overlap between the second sheet members 820 and the third sheet members 830 can be further suppressed. Therefore, the size of the electrode body, including the sheet members, can be further suppressed, and the storage element 10 can be made smaller or have a higher capacity.

[0080] By positioning the third sheet member 830 on a different side from all of the first sheet members 810 (the outer surface of the electrode body curved portions 613 and 713, and the outer surface of the electrode body curved portions 614 and 714), it is easy to position the third sheet member 830 in a location that does not overlap with all of the first sheet members 810. This makes it easy to realize a configuration that enables miniaturization or increased capacity of the energy storage element 10.

[0081] [5 Explanation of variations] Although an embodiment of the present invention has been described above, the present invention is not limited to this embodiment. The embodiments disclosed herein are illustrative in all respects, and the scope of the present invention includes all modifications in the sense and scope equivalent to the claims.

[0082] For example, in the above embodiment, the size and shape (width in the X-axis direction and length in the Z-axis direction, etc.) of the first sheet members 810 (811-816), the second sheet members 820 (821-826), and the third sheet members 830 (831-838) are not particularly limited. For example, the first sheet members 812 and 813 may have different widths, may be wider than the first sheet member 811, or may have a different length than the first sheet member 811. The same applies to the first sheet members 814-816. The same applies to the second sheet members 821-826 and the third sheet members 831-838.

[0083] In the above embodiment, the first sheet member 810 is positioned on both sides of the first electrode body 600 in the Y-axis direction and on the Z-axis direction. However, the first sheet member 810 only needs to be positioned between the first electrode body 600 and the second electrode body 700, and does not need to be positioned on the outer surface of the first electrode body 600 opposite to the second electrode body 700, nor does it need to be positioned on the Z-axis direction of the first electrode body 600. Similarly, the second sheet member 820 does not need to be positioned on the outer surface of the second electrode body 700 opposite to the first electrode body 600, nor does it need to be positioned on the Z-axis direction of the second electrode body 700. However, it is preferable that the first sheet member 810 be positioned on both sides of the first electrode body 600 in the Y-axis direction, as this allows the first electrode body 600 to be more securely fixed by being sandwiched in the Y-axis direction. The same applies to the second sheet member 820.

[0084] The third sheet member 830 does not necessarily have to be positioned on at least one of the surfaces of the first electrode body 600 opposite to the second electrode body 700, or on the surface of the second electrode body 700 opposite to the first electrode body 600. In particular, in the above embodiment, the third sheet member 837 is positioned from the outer surface of the electrode body flat portion 611, through the outer surfaces of the electrode body curved portion 613 and the electrode body curved portion 713, to the outer surface of the electrode body flat portion 712. However, the third sheet member 837 may not be positioned on at least one of the outer surfaces of the electrode body flat portion 611 and the electrode body flat portion 712, but rather on the outer surfaces of the electrode body curved portion 613 and the electrode body curved portion 713. However, it is preferable that the third sheet member 830 be positioned on both sides of the Y-axis direction of the first electrode body 600 and the second electrode body 700 so that the first electrode body 600 and the second electrode body 700 can be more securely fixed by being sandwiched in the Y-axis direction. In other words, it is preferable that the third sheet member 837 is positioned on the outer surfaces of the electrode body flat portion 611 and the electrode body flat portion 712, thereby sandwiching the first electrode body 600 and the second electrode body 700 in the Y-axis direction, as this allows for more secure fixing of the first electrode body 600 and the second electrode body 700. The same applies to the third sheet member 838.

[0085] In the above embodiment, the positions of the first sheet member 810 (811-816), the second sheet member 820 (821-826), and the third sheet member 830 (831-838) are not particularly limited, as long as they do not overlap with each other.

[0086] In the above embodiment, the number of the first sheet members 810, the second sheet members 820, and the third sheet members 830 is not particularly limited. That is, the first sheet members 810 may be seven or more, five or fewer, or just one. The second sheet members 820 may also be seven or more, five or fewer, or just one. The third sheet members 830 may be nine or more, seven or fewer, or just one. For example, in the third sheet member 830, the third sheet members 831 to 836 may be arranged without the third sheet members 837 and 838, or the third sheet members 837 and 838 may be arranged without the third sheet members 831 to 836. However, the latter is preferable because, by not arranging the third sheet members 831 to 836, the width of the first sheet member 810 and the second sheet member 820 can be increased, and by arranging the third sheet members 837 and 838, the first electrode body 600 and the second electrode body 700 can be stably fixed (bound) in place.

[0087] In the above embodiment, all first sheet members 810, all second sheet members 820, and all third sheet members 830 are positioned so as not to overlap. However, it is sufficient if at least one first sheet member 810 is positioned between the first electrode body 600 and the second electrode body 700 so as not to overlap with any of the second sheet members 820, or on the side of the first electrode body 600 opposite to the second electrode body 700 so as not to overlap with any of the third sheet members 830. For example, any of the first sheet members 810 may be positioned so as to overlap with a second sheet member 820, or so as to overlap with a third sheet member 830. Any of the second sheet members 820 may be positioned so as to overlap with a third sheet member 830.

[0088] In the above embodiment, the first electrode body 600 and the second electrode body 700 do not necessarily have a second sheet member 820 or a third sheet member 830. In other words, the first electrode body 600 and the second electrode body 700 may be housed in the container 100 without the third sheet member 830, as shown in Figure 6(a). Alternatively, the first electrode body 600 and the second electrode body 700 may be housed in the container 100 without the second sheet member 820, as shown in Figures 9A and 9B. Figures 9A and 9B are perspective views showing a modified example of this embodiment in which the second sheet member 820 is not placed on the first electrode body 600 and the second electrode body 700. Specifically, Figure 9A is a diagram obtained by removing the second sheet member 820 from Figure 6(b), and Figure 9B is a diagram obtained by removing the third sheet members 831 to 836 from Figure 9A. As mentioned above, the number of third sheet members 830 is not particularly limited, and it is preferable not to have third sheet members 831-836 than not to have third sheet members 837 and 838. Therefore, Figure 9B shows, as an example, Figure 9A with third sheet members 831-836 removed.

[0089] In the above embodiment, the first sheet member 810 is an insulating tape attached to the outer surface of the first electrode body 600. However, the first sheet member 810 may also be an insulating sheet wrapped around the first electrode body 600, or any sheet-like member that is placed on the outer surface of the first electrode body 600. Similarly, the second sheet member 820 may also be an insulating sheet wrapped around the second electrode body 700, or any sheet-like member that is placed on the outer surface of the second electrode body 700. Similarly, the third sheet member 830 may also be an insulating sheet wrapped around the first electrode body 600 and the second electrode body 700, or any sheet-like member that is placed on the outer surface of the first electrode body 600 and the second electrode body 700.

[0090] In the above embodiment, the first electrode body 600 and the second electrode body 700 are assumed to have an oval shape when viewed from the Z-axis direction, but they may also have an elliptical shape or the like, and their shape is not particularly limited. The first electrode body 600 and the second electrode body 700 are assumed to be so-called horizontally wound electrode bodies in which the winding axis is perpendicular to the cover body 120, but they may also be so-called vertically wound electrode bodies in which the winding axis is parallel to the cover body 120. The shape of the first electrode body 600 and the second electrode body 700 is not limited to a wound type, but may also be a stacked type in which flat plates are stacked, or a shape in which the plates are folded in a bellows shape, etc. The first electrode body 600 and the second electrode body 700 do not have tabs (tab bundles).

[0091] Embodiments constructed by arbitrarily combining the above embodiments and modifications are also included within the scope of the present invention.

[0092] The present invention can be realized not only as such an energy storage element 10, but also as a combination of the first electrode body 600 and the second electrode body 700 and the first sheet member 810 and the second sheet member 820 or the third sheet member 830. [Industrial applicability]

[0093] This invention can be applied to energy storage elements such as lithium-ion secondary batteries. [Explanation of symbols]

[0094] 10 Energy storage elements 100 containers 110 Container body 111 Long side wall section 112 Short side wall section 113 Bottom wall section 120 Lid 200 electrode terminal 300 Upper gasket 400 Lower gasket 500 Current collector 600 First electrode body 610, 710 Electrode body part 611, 612, 711, 712 Flat part of electrode body 613, 614, 713, 714 Electrode body curved section 620, 630, 720, 730 tab bundle 640, 740 positive electrode plate 641, 651, 741, 751 tabs 650, 750 negative electrode plate 661, 662, 761, 762 Separators 700 Second electrode body 810, 811, 812, 813, 814, 815, 816 First sheet member 820, 821, 822, 823, 824, 825, 826 Second sheet member 830, 831, 832, 833, 834, 835, 836, 837, 838 Third sheet member

Claims

1. A storage element comprising a first electrode body and a second electrode body, One or more first sheet members are disposed on the outer surface of the first electrode body and at a position including the space between the first electrode body and the second electrode body, The system comprises one or more second sheet members positioned on the outer surface of the second electrode body and including the space between the first electrode body and the second electrode body, or one or more third sheet members positioned on the outer surfaces of the first electrode body and the second electrode body extending across the first electrode body and the second electrode body, At least one of the first sheet members is positioned between the first electrode body and the second electrode body in a location that does not overlap with any of the second sheet members, or on the side of the first electrode body opposite to the second electrode body in a location that does not overlap with any of the third sheet members. Energy storage element.

2. The energy storage element comprises one or more second sheet members, All of the first sheet members are positioned between the first electrode body and the second electrode body, in a location that does not overlap with any of the second sheet members. The energy storage element according to claim 1.

3. The energy storage element comprises one or more third sheet members, All of the first sheet members are positioned on the side of the first electrode body opposite to the second electrode body, in a location where they do not overlap with any of the third sheet members. The energy storage element according to claim 1 or 2.

4. The energy storage element comprises one or more second sheet members and one or more third sheet members, At least one of the second sheet members is positioned on the side of the second electrode body opposite to the first electrode body, in a location that does not overlap with any of the third sheet members. The energy storage element according to any one of claims 1 to 3.

5. All of the second sheet members are positioned on the side of the second electrode body opposite to the first electrode body, in a location where they do not overlap with any of the third sheet members. The energy storage element according to claim 4.

6. The energy storage element comprises one or more third sheet members, At least one of the third sheet members is positioned on a side of the first electrode body and the second electrode body that is different from all of the first sheet members. The energy storage element according to any one of claims 1 to 5.

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