Electricity storage element and method for manufacturing the same

Abstract

To provide a power storage element in which sealability around a shaft body of an electrode terminal is improved.SOLUTION: A power storage element 10 includes: a container 100; an electrode terminal 200; and an upper insulation member 300. The electrode terminal 200 has: a terminal body 201 disposed outside the container 100; and a shaft body 210 which is connected to the terminal body 201 and arranged penetrating through a lid body 120, a wall part of the container 100. The upper insulation member 300 is disposed between the terminal body 201 and the lid body 120 of the container 100. A first seal part 50 and a second seal part 60, which are arranged side by side in a radial direction of the shaft body 210 and extend in a circumferential direction of the shaft body 210, are disposed in at least one of a space between the terminal body 201 and the upper insulation member 300 and a space between the upper insulation member 300 and the lid body 120. The second seal part 60 is formed of a material having flexibility higher than that of a material forming the first seal part 50.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to an energy storage element including a container and an electrode terminal having a shaft that penetrates the wall of the container, and a method for manufacturing the same. [Background technology]

[0002] Patent Document 1 discloses a nonaqueous electrolyte secondary battery including an external terminal located outside the battery case and an internal terminal located inside the battery case. In this nonaqueous electrolyte secondary battery, a protrusion on the internal terminal is disposed so as to penetrate the lid of the battery case, and the tip of the protrusion that penetrates the external terminal is crimped to connect to the external terminal. A gasket is disposed inside the battery case to seal the gap between the lid and the internal terminal, and the gasket includes a first gasket and a second gasket that are stacked in the axial direction of the protrusion. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-181544 Summary of the Invention [Problem to be solved by the invention]

[0004] In the conventional nonaqueous electrolyte secondary battery (energy storage element) described above, a gasket for sealing around the protrusion (shaft) connecting the external terminal and the internal terminal is disposed inside the battery case (container). Therefore, for example, if water infiltrates from around the external terminal (terminal body) toward the shaft, the gasket located inside the container cannot prevent the water from reaching the shaft. Furthermore, the gasket has two gaskets to improve its sealing function. However, because these two gaskets are stacked in the axial direction of the shaft, the effect of stacking the two gaskets may not be fully realized, for example, in preventing the movement of liquid in the radial direction of the shaft.

[0005] The present invention was made by the inventor of the present application with a new focus on the above-mentioned problem, and aims to provide a storage element with improved sealing around the shaft body of the electrode terminal, and a method for manufacturing the same. [Means for solving the problem]

[0006] A storage element according to one embodiment of the present invention is an energy storage element having a container, comprising: a terminal body arranged outside the container; an electrode terminal connected to the terminal body and having an axial body arranged to penetrate a wall portion of the container; and an insulating member arranged between the terminal body and the wall portion of the container, wherein a first seal portion and a second seal portion are arranged radially of the axial body and extend circumferentially of the axial body at least either between the terminal body and the insulating member or between the insulating member and the wall portion, and the second seal portion is formed of a material that is more flexible than the material forming the first seal portion.

[0007] A manufacturing method for a storage element according to one embodiment of the present invention is a manufacturing method for a storage element having a container, wherein the storage element comprises a terminal body arranged outside the container, an electrode terminal connected to the terminal body and having an axis arranged to penetrate a wall portion of the container, and an insulating member arranged between the terminal body and the wall portion of the container, and the manufacturing method includes an arrangement step of arranging a first seal portion and a second seal portion that are aligned radially of the axis and extend circumferentially of the axis body at least one between the terminal body and the insulating member and between the insulating member and the wall portion, and a compression step of pressing the terminal body toward the wall portion to compress the first seal portion and the second seal portion arranged in the axial direction of the axis body, wherein the second seal portion is formed of a material that is more flexible than the material that forms the first seal portion. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide an energy storage device in which the sealing performance around the shaft body of the electrode terminal is improved. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a perspective view showing the appearance of an energy storage element according to an embodiment; [Figure 2] FIG. 2 is an exploded perspective view of the energy storage element according to the embodiment. [Figure 3] FIG. 2 is an exploded perspective view showing the configuration of an electrode terminal and its surroundings according to the embodiment. [Figure 4] 1 is a first cross-sectional view showing the configuration of an electrode terminal and its surroundings according to an embodiment. [Figure 5] FIG. 4 is a second cross-sectional view showing the configuration of the electrode terminal and its surroundings according to the embodiment. [Figure 6] FIG. 6 is an enlarged cross-sectional view showing a part of FIG. 5 in an enlarged scale. [Figure 7] FIG. 10 is a third cross-sectional view showing the configuration of the electrode terminal and its surroundings according to the embodiment. [Figure 8] FIG. 10 is a cross-sectional view showing the configuration of an electrode terminal and its surroundings according to a modified example of the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] A storage element according to one embodiment of the present invention is an energy storage element having a container, comprising: a terminal body arranged outside the container; an electrode terminal connected to the terminal body and having an axial body arranged to penetrate a wall portion of the container; and an insulating member arranged between the terminal body and the wall portion of the container, wherein a first seal portion and a second seal portion are arranged radially of the axial body and extend circumferentially of the axial body at least either between the terminal body and the insulating member or between the insulating member and the wall portion, and the second seal portion is formed of a material that is more flexible than the material forming the first seal portion.

[0011] According to this configuration, two radially aligned seal portions are provided on the sides of the shaft that penetrates the wall of the container. These seal portions are crushed (compressed) between the terminal body and the insulating member or between the insulating member and the wall. This results in a dual radial arrangement of portions that prevent the movement of gas and liquid around the shaft, thereby improving the airtightness around the shaft. These two seal portions are located around the shaft and outside the container. Therefore, for example, liquid moving from the outside of the container toward the shaft of the electrode terminal can be stopped by the two seal portions. This suppresses corrosion of the shaft caused by the liquid. Furthermore, since one of the two seal portions (the second seal portion) is more flexible than the other (the first seal portion), for example, a situation in which both seal portions are insufficiently compressed can be avoided, and the less flexible seal portion (the first seal portion) can also be sufficiently compressed. This improves the effectiveness of improving the airtightness around the shaft by the two seal portions. In this way, the energy storage device according to this aspect is an energy storage device with improved airtightness around the shaft of the electrode terminal. The circumferential direction of the shaft is the direction along the outer periphery of the shaft and perpendicular to the axial direction of the shaft, and the radial direction of the shaft is the direction across the opposing outer peripheries of the shaft across the central axis of the shaft.

[0012] The first seal portion and the second seal portion may be compressed between the terminal body and the insulating member or between the insulating member and the wall portion, and the radial width of the compressed second seal portion may be larger than the radial width of the compressed first seal portion.

[0013] According to this configuration, the second seal portion, which is the softer of the two seal portions, is wider than the first seal portion. In other words, the second seal portion is formed to be wider after being compressed, allowing it to adhere to an insulating member or the like over a relatively wide area. This improves the sealing function of the second seal portion. In other words, an energy storage device with high sealing performance around the shaft body is obtained. The radial width of the second seal portion is defined as the radial width of the second seal portion after being compressed. In other words, the radial width of the second seal portion needs to be larger than the radial width of the first seal portion after being compressed.

[0014] The second seal portion may be disposed at a position farther from the shaft body in the radial direction than the first seal portion.

[0015] According to this configuration, the first seal portion is made of a material with low flexibility (high elasticity) and is positioned close to the shaft. In other words, the less flexible first seal portion is positioned in a position where the axial compressive force applied to the shaft when the electrode terminal is fixed to the wall portion is likely to act. This ensures that the first seal portion is compressed more reliably, and the second seal portion is also compressed sufficiently. Furthermore, for example, if a sealant is applied to the first seal portion to enhance its sealing function, the second seal portion on the outside reduces the possibility of the sealant coming into contact with the outside air. This suppresses deterioration of the sealant due to oxidation. This extends the life of the sealing function provided by the first seal portion.

[0016] The first seal portion and the second seal portion may be arranged between the terminal body and the insulating member, and the portion of the electrode terminal facing the first seal portion and the portion facing the second seal portion may be formed of different types of metal.

[0017] According to this configuration, when viewed in the axial direction of the shaft, an interface where different types of metals (dissimilar metals) in the electrode terminal come into contact exists between the first seal portion and the second seal portion. Therefore, for example, the possibility of liquids from the outside and inside of the container reaching the interface is reduced, thereby suppressing corrosion near the interface. This configuration is useful, for example, as a configuration around the shaft of a negative electrode terminal in which the shaft is made of copper or a copper alloy and the terminal body is made of aluminum or an aluminum alloy. It is also useful, for example, as a configuration around the shaft of a negative electrode terminal in which the terminal body is made of a clad material of copper or a copper alloy and aluminum or an aluminum alloy.

[0018] The first sealing portion may be formed by a part of the insulating member, and the second sealing portion may be formed by a member separate from the insulating member, the electrode terminal, and the wall portion.

[0019] According to this configuration, by providing the first seal portion integrally with the insulating member, it is possible to suppress an increase in the number of parts of the energy storage device. By making the second seal portion a separate member (separate part) from the insulating member, etc., it is possible to form the second seal portion from a material suitable for improving the sealing performance around the shaft body from various viewpoints such as flexibility, mechanical strength, and / or resistance to heat, etc.

[0020] A manufacturing method for a storage element according to one embodiment of the present invention is a manufacturing method for a storage element having a container, wherein the storage element comprises a terminal body arranged outside the container, an electrode terminal connected to the terminal body and having an axis arranged to penetrate a wall portion of the container, and an insulating member arranged between the terminal body and the wall portion of the container, and the manufacturing method includes an arrangement step of arranging a first seal portion and a second seal portion that are aligned radially of the axis and extend circumferentially of the axis body at least one between the terminal body and the insulating member and between the insulating member and the wall portion, and a compression step of pressing the terminal body toward the wall portion to compress the first seal portion and the second seal portion arranged in the axial direction of the axis body, wherein the second seal portion is formed of a material that is more flexible than the material that forms the first seal portion.

[0021] This manufacturing method provides an energy storage element having two radially aligned seal portions on the sides of a shaft that penetrates the wall of the container. In this energy storage element, a double radial arrangement of portions that prevent the movement of gas and liquid is achieved around the shaft, ensuring airtightness around the shaft. Having one of the two seal portions (the second seal portion) more flexible than the other (the first seal portion) prevents, for example, a situation in which both seal portions are insufficiently compressed, and the less flexible seal portion (the first seal portion) is also sufficiently compressed. This improves the effectiveness of improving airtightness around the shaft by the two seal portions. Thus, this manufacturing method for an energy storage element according to this aspect provides an energy storage element with improved airtightness around the shaft of the electrode terminal. The circumferential direction of the shaft is the direction along the outer periphery of the shaft and perpendicular to the axial direction of the shaft. The radial direction of the shaft is the direction across the opposing outer peripheries of the shafts.

[0022] Hereinafter, with reference to the drawings, an energy storage element according to an embodiment of the present invention will be described. The embodiments described below are all comprehensive or specific examples. The numerical values, shapes, materials, components, component placement and connection configurations, manufacturing processes, and the order of manufacturing processes shown in the following embodiments are merely examples and are not intended to limit the present invention. Furthermore, the dimensions and the like in each drawing are not strictly illustrated.

[0023] In the following description and drawings, the X-axis direction is defined as the direction in which a pair of electrode terminals (positive and negative) of an energy storage element are aligned, the direction in which a pair of current collectors are aligned, the direction in which a pair of tabs of an electrode assembly are aligned, or the direction in which the short side surfaces of a container face each other. The Y-axis direction is defined as the direction in which the long side surfaces of a container face each other, the short direction of the short side surfaces of a container, or the thickness direction of a container. The Z-axis direction is defined as the direction in which the terminal body, current collector, and electrode assembly of an electrode terminal are aligned, the direction in which the container body and lid of an energy storage element are aligned, the longitudinal direction of the short side surfaces of a container, the winding axis direction of the electrode assembly, or the up-down direction. The X-axis direction, Y-axis direction, and Z-axis direction intersect each other (orthogonal in this embodiment). Depending on the mode of use, the Z-axis direction may not be the up-down direction; however, for convenience of explanation, the Z-axis direction will be described below as the up-down direction.

[0024] In the following description, for example, the positive X-axis direction refers to the direction of the X-axis arrow, and the negative X-axis direction refers to the direction opposite to the positive X-axis direction. The same applies to the Y-axis and Z-axis directions. When simply referring to the X-axis direction, it refers to both or either of the positive X-axis direction and the negative X-axis direction. The same applies to the Y-axis and Z-axis directions. Expressions indicating relative directions or attitudes, such as parallel and orthogonal, also include cases where the directions or attitudes are not strictly those of the same kind. For example, when two directions are parallel, it does not only mean that the two directions are completely parallel, but also means that the directions are substantially parallel, that is, there is a difference of, for example, a few percent. Furthermore, in the following description, when the term "insulation" is used, it means "electrical insulation."

[0025] (Embodiment) [1. General explanation of energy storage elements] First, an energy storage device 10 according to the present embodiment will be generally described with reference to Figures 1 and 2. Figure 1 is a perspective view showing the appearance of the energy storage device 10 according to the embodiment. Figure 2 is an exploded perspective view of the energy storage device 10 according to the embodiment.

[0026] The energy storage device 10 is a secondary battery capable of charging and discharging electricity, specifically a nonaqueous electrolyte secondary battery such as a lithium-ion secondary battery. The energy storage device 10 is used, for example, as a battery for driving or starting the engine of a mobile object such as an automobile, motorcycle, personal watercraft, ship, snowmobile, agricultural machinery, construction machinery, or electric railway vehicle. Examples of the automobile include an electric vehicle (EV), a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), and a fossil fuel (gasoline, diesel, liquefied natural gas, etc.) vehicle. Examples of the electric railway vehicle include a train, a monorail, a linear motor car, and a hybrid train equipped with both a diesel engine and an electric motor. The energy storage device 10 can also be used as a stationary battery for home or business use.

[0027] The energy storage element 10 is not limited to a non-aqueous electrolyte secondary battery, and may be a secondary battery other than a non-aqueous electrolyte secondary battery, or may be a capacitor. The energy storage element 10 may also be a primary battery that can use stored electricity without the user having to charge it, instead of a secondary battery. The energy storage element 10 may also be a battery that uses a solid electrolyte. In this embodiment, the energy storage element 10 is illustrated as having a rectangular parallelepiped (cornered) shape, but the shape of the energy storage element 10 is not limited to a rectangular parallelepiped shape, and may be a polygonal prism shape, an elongated cylinder shape, or the like other than a rectangular parallelepiped shape.

[0028] As shown in FIG. 1, the energy storage device 10 includes a container 100, a pair of electrode terminals 200 (positive and negative electrodes, the same applies hereinafter), and a pair of upper insulating members 300. Also, as shown in FIG. 2, the container 100 contains a pair of lower insulating members 400, a pair of current collectors 500, and an electrode assembly 700. An electrolyte (non-aqueous electrolyte) is sealed inside the container 100, but this is not shown. The type of electrolyte is not particularly limited as long as it does not impair the performance of the energy storage device 10, and various electrolytes can be selected. In addition to the above-mentioned components, a spacer disposed above or to the side of the electrode assembly 700, or an insulating film enveloping the electrode assembly 700, etc., may also be disposed.

[0029] The container 100 is a rectangular parallelepiped (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. With this configuration, the container 100 has a structure in which the interior can be sealed by, for example, welding the container body 110 and the lid 120 together after the electrode assembly 700 and other components are housed inside the container body 110. The materials for the container body 110 and the lid 120 are not particularly limited, but are preferably weldable metals such as stainless steel, aluminum, aluminum alloy, iron, and plated steel sheet.

[0030] The container body 110 is a rectangular cylindrical member with a bottom that constitutes the main body of the container 100, and has an opening formed in the positive direction of the Z axis. The lid body 120 is a rectangular plate-like member that is long in the X axis direction and constitutes the lid of the container 100, and is positioned to close the opening of the container body 110. The lid body 120 is provided with a gas exhaust valve 122 that exhausts gas inside the container 100 when the internal pressure of the container 100 rises excessively.

[0031] The electrode assembly 700 is an electricity storage element (power generation element) that includes a positive electrode plate, a negative electrode plate, and a separator and can store electricity. The positive electrode plate is an electrode plate in which a composite layer containing a positive electrode active material is formed on a positive electrode substrate layer that is a long strip-shaped current collector foil made of aluminum or an aluminum alloy. The negative electrode plate is an electrode plate in which a composite layer containing a negative electrode active material is formed on a negative electrode substrate layer that is a long strip-shaped current collector foil made of copper or a copper alloy. In this embodiment, the electrode assembly 700 is formed by winding layers of positive and negative electrode plates with the separator sandwiched between them. This forms an electrode assembly main body 710 that includes a portion where the composite layer forming portion of the positive electrode plate and the composite layer forming portion of the negative electrode plate are stacked with the separator sandwiched between them. Furthermore, a plurality of tabs (composite layer non-forming portions) of the base material layer (metal foil) of the positive electrode plate are stacked to form the positive electrode tab portion 720, and a tab (composite layer non-forming portion) of the base material layer (metal foil) of the negative electrode plate are stacked to form the negative electrode tab portion 720. The tab portions 720 of the positive electrode and negative electrode are provided so as to protrude from the electrode body main body 710, as shown in FIG.

[0032] In this embodiment, the electrode assembly 700 has an oval cross-sectional shape, but the cross-sectional shape of the electrode assembly 700 may be an ellipse or other shape. The positive electrode active material and the negative electrode active material used in the composite layer may be any known material as long as they are active materials capable of absorbing and releasing lithium ions. The separator may be, for example, a microporous sheet or nonwoven fabric made of resin.

[0033] The electrode terminal 200 is a member electrically connected to the electrode body 700 via the current collector 500. The electrode terminal 200 is joined to the current collector 500 by crimping or the like, and is attached to the lid 120. Specifically, the electrode terminal 200 has a terminal body 201 disposed outside the container 100, and a shaft body 210 extending downward (in the negative Z-axis direction) from the terminal body 201. The shaft body 210 of the electrode terminal 200 is inserted into the through-hole 301 of the upper insulating member 300, the through-hole 121 of the lid 120, the through-hole 401 of the lower insulating member 400, and the through-hole 501 of the current collector 500, and is crimped. As a result, the electrode terminal 200, together with the upper insulating member 300, the lower insulating member 400, and the current collector 500, is fixed to the lid 120. The electrode terminal 200 is formed of a conductive material such as a metal, such as aluminum, an aluminum alloy, copper, or a copper alloy.

[0034] The current collector 500 is a plate-like member that electrically connects the electrode body 700 and the electrode terminal 200. The positive electrode current collector 500 is made of a metal such as aluminum or an aluminum alloy, and is joined to the positive electrode tab portion 720 of the electrode body 700. The negative electrode current collector 500 is made of a metal such as copper or a copper alloy, and is joined to the negative electrode tab portion 720 of the electrode body 700. The current collector 500 and the tab portion 720 may be joined by laser welding, resistance welding, ultrasonic welding, or the like.

[0035] The upper insulating member 300 is a flat plate-shaped member disposed between the lid 120 of the container 100 and the electrode terminal 200. The lower insulating member 400 is a flat plate-shaped member disposed between the lid 120 and the current collector 500. In this embodiment, the upper insulating member 300 and the lower insulating member 400 serve to insulate the electrode terminal 200 from the lid 120 of the container 100. The upper insulating member 300 and the lower insulating member 400 are formed from an insulating material such as a resin such as polypropylene (PP), polyethylene (PE), polyphenylene sulfide resin (PPS), polyethylene terephthalate (PET), polyether ether ketone (PEEK), tetrafluoroethylene-perfluoroalkyl vinyl ether (PFA), polytetrafluoroethylene (PTFE), polybutylene terephthalate (PBT), or polyethersulfone (PES), or a composite material containing these resins.

[0036] In addition to the upper insulating member 300 and lower insulating member 400 described above, the energy storage device 10 according to this embodiment is provided with two seal portions arranged near the shaft body 210 and aligned in the radial direction of the shaft body 210 as members for improving the sealing performance around the shaft body 210 of the electrode terminal 200. In FIG. 2, the second seal portion of the two seal portions is designated by the reference numeral "60." In this embodiment, second seal portions 60 are respectively arranged between the terminal body 201 and the upper insulating member 300, and between the upper insulating member 300 and the lid body 120. The two seal portions aligned in the radial direction, including the second seal portion 60, and the surrounding configuration will be described below with reference to FIGS. 3 to 7.

[0037] [2. Configuration of the first seal part, second seal part and their surroundings] FIG. 3 is an exploded perspective view showing an electrode terminal 200 and its peripheral configuration according to an embodiment. FIG. 4 is a first cross-sectional view showing an electrode terminal 200 and its peripheral configuration according to an embodiment. FIG. 4 is a cross-section of the electrode terminal 200 of the energy storage device 10 and its peripheral portion, taken along line IV-IV in FIG. 3. FIG. 5 is a second cross-sectional view showing the electrode terminal 200 and its peripheral configuration according to an embodiment. FIG. 6 is an enlarged cross-sectional view showing a portion of FIG. 5. FIG. 7 is a third cross-sectional view showing the electrode terminal 200 and its peripheral configuration according to an embodiment. The position of the cross-section in FIGS. 5 and 7 is the same as the position of the cross-section in FIG. 4. In FIGS. 4 to 7, the two upper and lower first seal portions 50 of the upper insulating member 300 are given different reference numerals (50a, 50b) to distinguish them from each other, and similarly, the two upper and lower second seal portions 60 are given different reference numerals (60a, 60b) to distinguish them from each other.

[0038] As shown in FIGS. 3 to 7 , energy storage device 10 according to this embodiment includes electrode terminal 200 arranged in lid 120 of container 100. Electrode terminal 200 has terminal body 201 and shaft body 210. Specifically, terminal body 201 is the flat plate-shaped upper portion of electrode terminal 200, and shaft body 210 is the rod-shaped portion protruding downward from flat terminal body 201. In this embodiment, terminal body 201 of electrode terminal 200 is arranged on the outside of container 100, and shaft body 210 of electrode terminal 200 is arranged so as to pass through through-hole 121 of lid 120.

[0039] More specifically, the electrode terminal 200 shown in FIGS. 3 to 7 is a negative electrode terminal of the energy storage element 10. The member that constitutes the terminal body 201 is made of aluminum or an aluminum alloy. The member that constitutes the shaft body 210 is made of copper or a copper alloy. In this embodiment, as shown in FIG. 4, the end of the member that constitutes the shaft body 210 is embedded in the member that constitutes the terminal body 201. In other words, the terminal body 201 is made of two types of metal members, and the boundary between the different metals is exposed on the lower surface of the terminal body 201 (the surface facing the upper insulating member 300).

[0040] As shown in FIGS. 5 and 7 , the cylindrical portion 320 of the upper insulating member 300 is inserted into the gap between the outer peripheral surface of the shaft 210 of the electrode terminal 200 configured in this manner and the inner peripheral surface of the through-hole 121 of the lid 120. That is, the gap is filled with a portion of the upper insulating member 300. More specifically, a force in the axial direction (hereinafter simply referred to as the “axial direction”) of the shaft 210, which is applied to the shaft 210 when the shaft 210 is crimped, acts on the shaft 210 so as to expand the outer diameter of the shaft 210. Furthermore, a crimped portion 211 (see FIG. 7 ) that expands in the radial direction (hereinafter simply referred to as the “radial direction”) of the shaft 210 is formed at the tip of the shaft 210. As a result, the axial force applied to the shaft 210 acts on the cylindrical portion 320 via the current collector 500 and the lower insulating member 400 so as to compress the cylindrical portion 320 in the axial direction. As a result, the wall portion forming cylindrical portion 320 is firmly sandwiched in the radial direction between the inner peripheral surface of through hole 121 and the outer peripheral surface of shaft body 210. This seals the gap between the inner peripheral surface of through hole 121 in lid body 120 and the outer peripheral surface of shaft body 210, and in principle, ensures airtightness at the position of through hole 121 in lid body 120.

[0041] The energy storage device 10 according to this embodiment further includes a first seal portion 50 and a second seal portion 60 arranged side by side in the radial direction of the shaft body 210 outside the container 100. Specifically, in this embodiment, the first seal portion 50 is an annular protruding portion integrally formed on the upper insulating member 300. That is, the first seal portion 50, like the upper insulating member 300, is formed of a resin material such as PP, PE, or PPS. In this embodiment, the second seal portion 60 is an annular member generally called an O-ring, and is formed of rubber such as silicone rubber, ethylene propylene diene rubber (EPDM), fluororubber, nitrile rubber, styrene butadiene rubber, butyl rubber, hydrogenated nitrile rubber, acrylic rubber, chloroprene rubber, or urethane rubber. That is, the second seal portion 60 is formed of a material that is more flexible than the material forming the first seal portion 50.

[0042] In this embodiment, the first seal portion 50 and the second seal portion 60 are concentrically arranged around the shaft body 210 in a plan view (viewed from the positive direction of the Z axis). For example, focusing on the area between the upper insulating member 300 and the terminal body 201, as shown in FIGS. 3 to 7, the first seal portion 50a is arranged around the through-hole 301 of the upper insulating member 300, and the second seal portion 60a is arranged further outside of the first seal portion 50a. The second seal portion 60a is arranged in a accommodating portion 310, which is an annular groove formed in the upper surface of the upper insulating member 300. The depth of the accommodating portion 310 is, for example, approximately 70% of the height (axial width) of the second seal portion 60a before compression. Therefore, as shown in FIGS. 5 and 6, before the second seal portion 60a is compressed, a portion of the second seal portion 60a in the axial direction is accommodated in the accommodating portion 310.

[0043] That is, as shown in FIGS. 5 and 6 , the first seal portion 50a and the second seal portion 60a protrude upward from the upper insulating member 300 before the shaft body 210 of the electrode terminal 200 is crimped. When the shaft body 210 is subsequently crimped, the first seal portion 50a and the second seal portion 60a are compressed by the terminal body 201 and the upper insulating member 300 and come into firm contact with the terminal body 201, as shown in FIG. 7 . The second seal portion 60a, which is separate from the upper insulating member 300, also comes into firm contact with the upper insulating member 300. As a result, the first seal portion 50a and the second seal portion 60a function as two sealing portions aligned radially between the terminal body 201 and the upper insulating member 300. In other words, the gas and liquid passages connecting the outside and inside of the container 100 between the terminal body 201 and the upper insulating member 300 are doubly blocked by the first seal portion 50a and the second seal portion 60a.

[0044] Furthermore, in the energy storage device 10 according to the present embodiment, focusing on the area between the upper insulating member 300 and the wall portion (lid 120) of the container 100, as shown in FIGS. 3 to 7, a first seal portion 50b is disposed around the periphery of the cylindrical portion 320, and a second seal portion 60b is disposed further outside the first seal portion 50b. The second seal portion 60b is disposed in a housing portion 125, which is an annular groove formed in the upper surface of the lid 120. The depth of the housing portion 125 is, for example, approximately 70% of the height (axial width) of the second seal portion 60b before compression. Therefore, as shown in FIGS. 5 and 6, before the second seal portion 60b is compressed, a portion of the second seal portion 60b in the axial direction is housed in the housing portion 125.

[0045] That is, as shown in FIG. 6, for example, before the shaft body 210 of the electrode terminal 200 is crimped, the first seal portion 50b and the second seal portion 60b protrude from one of the upper insulating member 300 and the lid body 120 toward the other. When the shaft body 210 is subsequently crimped, the first seal portion 50b and the second seal portion 60b are compressed by the upper insulating member 300 and the lid body 120, as shown in FIG. 7, and come into firm contact with the lid body 120. The second seal portion 60b, which is separate from the upper insulating member 300, also comes into firm contact with the upper insulating member 300. As a result, the first seal portion 50b and the second seal portion 60b function as two sealing portions aligned radially between the upper insulating member 300 and the lid body 120. In other words, the gas and liquid passages connecting the outside and inside of the container 100 between the upper insulating member 300 and the top surface of the lid 120 are doubly blocked by the first seal portion 50b and the second seal portion 60b.

[0046] As described above, the energy storage device 10 according to this embodiment includes the container 100, the electrode terminal 200, and the upper insulating member 300. The electrode terminal 200 has a terminal body 201 disposed outside the container 100, and a shaft body 210 connected to the terminal body 201 and disposed so as to penetrate the lid body 120, which is a wall portion of the container 100. The upper insulating member 300 is disposed between the terminal body 201 and the lid body 120 of the container 100. The first seal portion 50 and the second seal portion 60 are disposed between the terminal body 201 and the upper insulating member 300, or between the upper insulating member 300 and the lid body 120, and are aligned in the radial direction of the shaft body 210 and extend in the circumferential direction of the shaft body 210. The second seal portion 60 is formed of a material that is more flexible than the material forming the first seal portion 50.

[0047] As described above, in this embodiment, the first seal portion 50 and the second seal portion 60 are provided radially aligned on the sides of the shaft 210 that penetrates the lid 120 of the container 100. These two seal portions are crushed (compressed) between the terminal body 201 and the upper insulating member 300, or between the upper insulating member 300 and the lid 120. This results in a dual radial arrangement of portions that stop the movement of gas and liquid around the shaft 210, thereby improving the airtightness around the shaft 210. These two seal portions are arranged around the shaft 210 and outside the container 100. Therefore, the two seal portions can stop liquid that moves from the outside of the container 100 toward the shaft 210 of the electrode terminal 200. This suppresses corrosion of the shaft 210 caused by the liquid.

[0048] Furthermore, one of the two seal portions (the second seal portion 60) is formed of a material that is more flexible than the other (the first seal portion 50). In other words, the second seal portion 60 is formed of a material that has a lower bulk modulus (hereinafter simply referred to as "elastic modulus") than the material that forms the first seal portion 50. Therefore, for example, a state in which both seal portions are not sufficiently compressed is avoided, and the less flexible seal portion (the first seal portion 50) is also sufficiently compressed. This improves the effectiveness of improving the sealing performance around the shaft body 210 by the two seal portions. In this way, the energy storage device 10 according to this embodiment is an energy storage device 10 in which the sealing performance around the shaft body 210 of the electrode terminal 200 is improved.

[0049] More specifically, in this embodiment, the first seal portion 50a and the second seal portion 60a are arranged between the terminal body 201 and the upper insulating member 300, and the first seal portion 50b and the second seal portion 60b are arranged between the upper insulating member 300 and the lid 120. In other words, the first seal portion 50 and the second seal portion 60 are arranged on both sides of the upper insulating member 300 in the axial direction of the shaft body 210. Therefore, the sealing performance around the shaft body 210 in the energy storage device 10 is improved compared to when the first seal portion 50 and the second seal portion 60 are arranged on only one side of the upper insulating member 300.

[0050] In this embodiment, as described above, the material forming the second seal portion 60 is more flexible (has a lower elastic modulus) than the material forming the first seal portion 50. A compression test is used to measure the elastic modulus of the material of the compressed first seal portion 50 and the compressed second seal portion 60. That is, if the first seal portion 50 is formed of material A and the second seal portion 60 is formed of material B, a test piece a made of material A and a test piece b made of material B are prepared. A compressive load is then applied to each of test piece a and test piece b to determine their respective displacements, thereby calculating the elastic moduli of material A and material B. If the first seal portion 50 is formed as a part of the upper insulating member 300, a compression test is performed using a part of the upper insulating member 300 as test piece a. If the first seal portion 50 is formed as a separate member from the upper insulating member 300, test piece a is prepared from the first seal portion 50 and a compression test is performed.

[0051] In this embodiment, focusing on the radial widths of the first seal portion 50 and the second seal portion 60, as shown in Fig. 6, the first seal portion 50 and the second seal portion 60 are compressed between the terminal body 201 and the upper insulating member 300 or between the upper insulating member 300 and the cover 120. The radial width Wb of the compressed second seal portion 60 is greater than the radial width Wa of the compressed first seal portion 50. In this embodiment, the first seal portion 50a and the second seal portion 60a are compressed between the terminal body 201 and the upper insulating member 300, and the first seal portion 50b and the second seal portion 60b are compressed between the upper insulating member 300 and the cover 120.

[0052] In this way, of the two seal portions provided in the energy storage device 10, the second seal portion 60, which is the softer, is wider than the first seal portion 50. That is, in this embodiment, after being crimped, the second seal portion 60 can come into close contact with the upper insulating member 300 and the like over a relatively wide area. This improves the sealing function of the second seal portion 60. That is, the energy storage device 10 can be obtained with a high degree of sealing tightness around the shaft body 210.

[0053] 6, the radial width Wa of the first seal portion 50 and the radial width Wb of the second seal portion 60 are shown in a state before the shaft body 210 is crimped, for ease of comparison. However, in the energy storage device 10 according to the present embodiment, even after the shaft body 210 has been crimped (see FIG. 7), the radial width Wb of the second seal portion 60 is greater than the radial width Wa of the first seal portion 50. In other words, the second seal portion 60, which is made of a relatively flexible material, has good adhesion and a relatively wide radial width, and is therefore highly effective in suppressing the movement of gases and liquids.

[0054] In this embodiment, the radial width Wb of the second seal portion 60, which is a separate component from the upper insulating member 300, can be measured even after the shaft body 210 is crimped. The first seal portion 50, which is integral with the upper insulating member 300, also has a zero volume due to compression. However, when disassembled, the compression returns, making it identifiable as a slightly raised portion. In other words, the width Wa of the first seal portion 50 can be measured by enlarging and observing a cross section of the upper insulating member 300 parallel to the axial direction of the shaft body 210. If the radial width Wa of the first seal portion 50 is not constant in the circumferential direction, the value of the width Wa is determined by averaging the values ​​of the width Wa at multiple locations in the circumferential direction. Similarly, if the radial width Wb of the second seal portion 60 is not constant in the circumferential direction, the value of the width Wb is determined by averaging the values ​​of the width Wb at multiple locations in the circumferential direction.

[0055] In this embodiment, when attention is paid to the positional relationship between the first seal portion 50 and the second seal portion 60, the second seal portion 60 is positioned farther from the shaft body 210 in the radial direction of the shaft body 210 than the first seal portion 50.

[0056] That is, in this embodiment, the first seal portion 50, which is made of a material with low flexibility (high elastic modulus), is disposed near the shaft body 210. In other words, the less flexible first seal portion 50 is disposed in a position where the axial compressive force applied to the shaft body 210 is likely to act when the electrode terminal 200 is fixed to the lid 120 (when the shaft body 210 is crimped). This ensures that the first seal portion 50 is compressed more reliably, and the second seal portion 60 is also sufficiently compressed. Furthermore, for example, if a sealant is applied to the first seal portion 50 to enhance its sealing function, the second seal portion 60 on the outside reduces the possibility of the sealant coming into contact with the outside air. This suppresses deterioration of the sealant due to oxidation. As a result, the sealing function of the first seal portion 50 has a longer life. Furthermore, the possibility of the second seal portion 60, which is disposed on the outside of the first seal portion 50 (farther from the shaft body 210), coming into contact with the electrolyte is reduced. Therefore, a material that does not require electrolyte resistance can be selected as the material for the second seal portion 60. In other words, the degree of freedom in selecting the material for the second seal portion 60 is improved.

[0057] 7, the first seal portion 50a and the second seal portion 60a are disposed between the terminal body 201 and the upper insulating member 300. In the electrode terminal 200, the portion facing the first seal portion 50a and the portion facing the second seal portion 60a are formed of different types of metal. Specifically, in this embodiment, the portion of the electrode terminal 200 made of copper or a copper alloy is disposed at a position facing the first seal portion 50a. The portion of the electrode terminal 200 made of aluminum or an aluminum alloy is disposed at a position facing the second seal portion 60.

[0058] That is, when viewed from the axial direction of the shaft body 210, an interface where different types of metals (dissimilar metals) in the electrode terminal 200 come into contact exists between the first seal portion 50 and the second seal portion 60. Therefore, for example, the possibility that liquids from the outside and inside of the container 100 reach the interface is reduced, thereby suppressing corrosion near the interface.

[0059] The first seal portion 50 and the second seal portion 60 may be part of various constituent elements of the energy storage device 10, or may be separate members (separate components). In the present embodiment, the first seal portion 50 is formed by part of the upper insulating member 300. The second seal portion 60 is formed by a member separate from the upper insulating member 300, the electrode terminal 200, and the lid 120.

[0060] According to this configuration, by providing the first seal portion 50 integrally with the upper insulating member 300, it is possible to suppress an increase in the number of parts of the energy storage device 10. By making the second seal portion 60 a separate member (separate part) from the upper insulating member 300, etc., it is possible to form the second seal portion 60 from a material suitable for improving the sealing performance around the shaft body 210 from various viewpoints such as flexibility, mechanical strength, and / or resistance to heat, etc.

[0061] A manufacturing method for the energy storage device 10 according to this embodiment is described, for example, as follows. The energy storage device 10 includes a container 100, an electrode terminal 200, and an upper insulating member 300. The electrode terminal 200 has a terminal body 201 arranged outside the container 100, and a shaft body 210 connected to the terminal body 201 and arranged to penetrate a lid body 120, which is a wall portion of the container 100. The upper insulating member 300 is arranged between the terminal body 201 and the lid body 120 of the container 100. The manufacturing method includes an arrangement step of arranging the first seal portion 50 and the second seal portion 60, and a compression step of compressing the first seal portion 50 and the second seal portion 60 in the axial direction of the shaft body 210. In the arrangement step, as shown in Figures 3 to 6, the first seal portion 50 and the second seal portion 60 are arranged radially of the shaft body 210 and extend circumferentially of the shaft body 210 between the terminal body 201 and the upper insulating member 300, or between the upper insulating member 300 and the lid body 120. In the compression step, as shown in Figure 7, the terminal body 201 is pressed against the lid body 120, thereby compressing the first seal portion 50 and the second seal portion 60 arranged in the arrangement step in the axial direction of the shaft body 210. The second seal portion 60 is made of a material that is more flexible than the material from which the first seal portion 50 is made.

[0062] This manufacturing method provides an energy storage device 10 having two radially aligned seal portions provided on the sides of the shaft 210 that penetrates the lid 120 of the container 100. In this energy storage device 10, as described above, a double radial arrangement of portions that prevent the movement of gas and liquid is provided around the shaft 210, resulting in improved airtightness around the shaft 210. Having one of the two seal portions (the second seal portion 60) more flexible than the other (the first seal portion 50) prevents, for example, a situation in which both seal portions are insufficiently compressed, and the less flexible seal portion (the first seal portion 50) is also sufficiently compressed. This improves the effectiveness of improving the airtightness around the shaft 210 using the two seal portions. Thus, the manufacturing method for the energy storage device 10 according to this embodiment provides an energy storage device 10 having improved airtightness around the shaft 210 of the electrode terminal 200. The second seal portion 60 being more flexible than the first seal portion 50 means that the second seal portion 60 after compression has a lower elastic modulus than the first seal portion 50 after compression. The elastic modulus is determined by measuring the elastic modulus of the materials of the first seal portion 50 and the second seal portion 60 through a compression test. That is, if the first seal portion 50 is formed from material A and the second seal portion 60 is formed from material B, a test piece a made from material A and a test piece b made from material B are prepared. Furthermore, a compressive load is applied to each of test piece a and test piece b, and the respective displacements are measured, thereby calculating the elastic moduli of materials A and B. If the first seal portion 50 is formed as a part of the upper insulating member 300, a compression test is performed using a part of the upper insulating member 300 as test piece a. If the first seal portion 50 is formed as a separate member from the upper insulating member 300, test piece a is prepared from the first seal portion 50 and a compression test is performed.

[0063] 3. Modifications of the Embodiments Although the energy storage device according to the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment. In other words, the disclosed embodiment is an example in all respects, and includes all modifications within the meaning and scope of the claims.

[0064] For example, the two first seal portions 50 arranged on both sides of the upper insulating member 300 in the axial direction of the shaft body 210 do not need to be arranged in the same position when viewed from the axial direction. The same is true for the second seal portions 60; the two second seal portions 60 arranged on both sides of the upper insulating member 300 in the axial direction do not need to be arranged in the same position when viewed from the axial direction.

[0065] FIG. 8 is a cross-sectional view showing an electrode terminal and its surrounding structure according to a modified example of the embodiment. In an energy storage device 10a according to this modified example, as shown in FIG. 8, an electrode terminal 200 includes a terminal body 201 disposed outside the container 100 and a shaft body 210 disposed to penetrate the lid body 120a. An upper insulating member 300 is disposed between the terminal body 201 and the lid body 120a. A first seal portion 50a and a second seal portion 60a are disposed between the terminal body 201 and the upper insulating member 300, aligned in the radial direction of the shaft body 210 and extending in the circumferential direction of the shaft body 210. A first seal portion 50c and a second seal portion 60c are disposed between the upper insulating member 300 and the lid body 120a, aligned in the radial direction of the shaft body 210 and extending in the circumferential direction of the shaft body 210. The second seal portion 60a is formed of a material that is more flexible than the material forming the first seal portion 50a. The second seal portion 60c is made of a material that is more flexible than the material that forms the first seal portion 50c. The second seal portion 60a is housed in a housing portion 310 provided in the upper insulating member 300, and the first seal portion 60c is housed in a housing portion 125a provided in the lid body 120a. These configurations are common to the energy storage device 10 according to the embodiment.

[0066] In this modification, the first seal portions 50a and 50c are disposed at positions that are radially offset from each other when viewed from the axial direction of the shaft body 210. Furthermore, the second seal portions 60a and 60c are disposed at positions that are radially offset from each other when viewed from the axial direction of the shaft body 210.

[0067] Thus, even if the positions of the first seal portions 50a and 50c do not coincide when viewed from the axial direction, the first seal portions 50a and 50c are located within the arrangement range of the terminal body 201 when viewed from the axial direction. Therefore, each of the first seal portions 50a and 50c can withstand the compressive force generated when the shaft body 210 is crimped. As a result, the first seal portion 50a can fill the gap between the upper insulating member 300 and the terminal body 201, and the first seal portion 50c can fill the gap between the upper insulating member 300 and the cover 120a. Even if the positions of the second seal portions 60a and 60c do not coincide when viewed from the axial direction, the second seal portions 60a and 60c are located within the arrangement range of the terminal body 201 when viewed from the axial direction. Therefore, each of the second seal portions 60a and 60c can withstand the compressive force generated when the shaft body 210 is crimped. As a result, the second sealing portion 60a can fill the gap between the upper insulating member 300 and the terminal body 201, and the second sealing portion 60c can fill the gap between the upper insulating member 300 and the lid body 120a.

[0068] That is, the positions of the first seal portions 50a and 50c and the second seal portions 60a and 60c when viewed from the axial direction need only be positions where they are compressed by the terminal body 201 and the upper insulating member 300, or by the upper insulating member 300 and the lid 120a, when the shaft 210 is crimped. This allows the first seal portions 50a and 50c and the second seal portions 60a and 60c to contribute to improving the sealing performance around the shaft 210.

[0069] For example, the positions of the first seal portions 50a and 50c when viewed in the axial direction are compared by comparing the positions of their respective center lines. The center line of the first seal portion 50 is a line that passes through the center of the radial width (the distance between the outer and inner circumferences) of the first seal portion 50 when viewed in the axial direction. In other words, if at least a portion of the center line of one of the two first seal portions 50 does not overlap with the center line of the other when viewed in the axial direction, the positions of these two first seal portions 50 when viewed in the axial direction will not match. This also applies to comparing the positions of the second seal portions 60a and 60c when viewed in the axial direction.

[0070] Furthermore, when the positions of the two first seal portions 50 coincide when viewed from the axial direction, as in the above embodiment (see FIG. 7), for example, the compressive force applied when the shaft body 210 is crimped is evenly applied to the two first seal portions 50. Therefore, when the two first seal portions 50 have the same shape, for example, this is advantageous in that the two first seal portions 50 are evenly compressed. On the other hand, when the positions of the two first seal portions 50 do not coincide when viewed from the axial direction, as in this modified example, this is advantageous in that it reduces stress concentration occurring in the members surrounding the two first seal portions 50 and suppresses cracking of the members, for example.

[0071] The energy storage device 10 does not need to have the first seal portion 50 and the second seal portion 60 both between the upper insulating member 300 and the terminal body 201 and between the upper insulating member 300 and the lid 120. For example, the first seal portion 50 (50a) and the second seal portion 60 (60a) may be provided only between the upper insulating member 300 and the terminal body 201. This reduces the possibility that liquids from the inside and outside of the container 100 will reach the interface where the different metals come into contact in the negative electrode terminal 200 formed from a combination of two types of metal materials, as in the above embodiment.

[0072] In the above embodiment, an aspect in which the first sealing portion 50 and the second sealing portion 60 are arranged relative to the negative electrode terminal 200 has been described, but the first sealing portion 50 and the second sealing portion 60 may also be arranged relative to the positive electrode terminal 200.

[0073] The first seal portion 50 and the second seal portion 60 do not have to be spaced apart in the radial direction of the shaft body 210, and may be arranged continuously in the radial direction. Even in this case, the first seal portion 50 and the second seal portion 60 are compressed when the shaft body 210 is crimped, and as a result, the gap between the upper insulating member 300 and the terminal body 201 or between the upper insulating member 300 and the lid 120 can be filled. In other words, the sealing performance around the shaft body 210 can be improved.

[0074] The positional relationship between the first seal portion 50 and the second seal portion 60 in the radial direction of the shaft body 210 may be reversed from that in the above embodiment. That is, the second seal portion 60 may be arranged closer to the shaft body 210, and the first seal portion 50 may be arranged on the outer periphery of the second seal portion 60. Even in this case, it is possible to arrange two portions in the radial direction around the shaft body 210 that stop the movement of gas and liquid.

[0075] The first sealing portion 50 does not have to be integrally formed with the upper insulating member 300. Like the second sealing portion 60, the first sealing portion 50 may be provided in the energy storage device 10 as a separate member (separate component) from the upper insulating member 300, etc.

[0076] The cross-sectional shapes of the first seal portion 50 and the second seal portion 60 are not limited to the shapes shown in Fig. 6 etc. For example, the cross-sectional shape of the first seal portion 50 may be a tapered shape that is easily compressed (crushed). The second seal portion 60 may be an O-ring with a rectangular cross-sectional shape.

[0077] The method of joining shaft 210 and current collector 500 is not limited to crimping. For example, shaft 210 and current collector 500 may be joined by providing a thread on the outer periphery of the tip of shaft 210 and tightening a nut onto the tip while the nut passes through through-hole 501 of current collector 500. In this case, tightening the nut onto the tip of shaft 210 can compress first seal portion 50 and second seal portion 60, which are arranged between upper insulating member 300 and terminal body 201 and / or between upper insulating member 300 and lid 120.

[0078] The terminal body and shaft of the energy storage element 10 may be joined during manufacturing (assembly) of the energy storage element 10. For example, a shaft fixed to the current collector 500 may be joined to the terminal body located above the upper insulating member 300 in a state in which the shaft penetrates the lower insulating member 400, the lid 120, and the upper insulating member 300. In this case, the terminal body and the shaft are joined by a joining method such as crimping or fastening with a nut (screwing a nut onto the shaft), similar to the joining method between the shaft 201 and the current collector 500 according to the embodiment. In other words, the shaft of the electrode terminal of the energy storage element 10 may be provided integrally with another member, such as the current collector 500, at a stage prior to manufacturing the energy storage element 10. Even in this case, the first seal portion 50 and the second seal portion 60 still have the effect of improving the sealing performance around the shaft of the electrode terminal.

[0079] In the container 100, the wall portion in which the through hole 121 through which the shaft body 210 is disposed may be formed may be other than the lid 120. For example, in the container 100 constituted by the lid 120 and the container body 110, the through hole 121 may be formed in any of the five walls (bottom wall portion and four side wall portions) of the container body 110. In other words, there is no particular limitation on the position in which the electrode terminal 200 is disposed in the energy storage element 10.

[0080] The type of electrode body included in the energy storage element 10 is not limited to a wound type. For example, the energy storage element 10 may be provided with a laminated electrode body in which flat electrode plates are stacked, or an electrode body having a structure in which long strip-shaped electrode plates are stacked in an accordion-like shape by repeatedly folding in peaks and valleys. The energy storage element 10 may also be provided with a plurality of electrode bodies.

[0081] The electrode assembly included in the energy storage device 10 does not need to be an electrode assembly in which positive and negative electrode tab portions protrude from the electrode assembly body, such as the electrode assembly 700 according to the embodiment (see FIG. 2 ). For example, the energy storage device 10 may be provided with an electrode assembly having a connection portion in which electrode plate base material layers (metal foils) are laminated on both ends of the short side surfaces of the container 100 in the opposing direction (X-axis direction). In this case, the current collector connecting the connection portion of the electrode assembly to the electrode terminal 200 may have a portion to which the shaft body 210 of the electrode terminal 200 is joined, such as the current collector 500 according to the embodiment, and a leg portion extending downward from that portion and joined to the connection portion of the electrode assembly. In other words, regardless of the shape, size, etc. of the current collector included in the energy storage device 10, the function of the first seal portion 50 and the second seal portion 60 to improve the sealing around the shaft body 210 is not impaired.

[0082] Any combination of the above-described components is also included within the scope of the present invention. [Industrial Applicability]

[0083] The present invention can be applied to an electric storage element such as a lithium ion secondary battery. [Explanation of symbols]

[0084] 10, 10a Storage element 50, 50a, 50b, 50c First seal part 60, 60a, 60b, 60c Second seal portion 100 containers 110 Container body 120, 120a lid body 121, 301, 401, 501 through holes 122 Gas exhaust valve 125,125a Storage area 200 electrode terminal 201 Terminal body 210 Shaft 211 Crimping part 300 Upper insulating member 310 Storage unit 320 Cylindrical part 400 Lower insulating member 500 current collector 700 Electrode body 710 Electrode body 720 Tab section

Claims

1. An energy storage element including a container, an electrode terminal having a terminal body disposed outside the container and a shaft body connected to the terminal body and disposed so as to penetrate a wall portion of the container; an insulating member disposed between the terminal body and the wall of the container, a first seal portion and a second seal portion are arranged side by side in the radial direction of the shaft body and extend in the circumferential direction of the shaft body at least one between the terminal body and the insulating member and between the insulating member and the wall portion; The second seal portion is formed of a material that is more flexible than the material that forms the first seal portion. Energy storage element.

2. the first seal portion and the second seal portion are compressed between the terminal body and the insulating member or between the insulating member and the wall portion, and the radial width of the compressed second seal portion is larger than the radial width of the compressed first seal portion; The energy storage element according to claim 1.

3. In the radial direction, the second seal portion is disposed at a position farther from the shaft body than the first seal portion. The energy storage element according to claim 1 or 2.

4. the first seal portion and the second seal portion are disposed between the terminal body and the insulating member, In the electrode terminal, a portion facing the first seal portion and a portion facing the second seal portion are formed of different types of metals. The energy storage element according to any one of claims 1 to 3.

5. the first seal portion is formed by a part of the insulating member, the second sealing portion is formed by a member separate from the insulating member, the electrode terminal, and the wall portion. The energy storage element according to any one of claims 1 to 4.

6. A method for manufacturing an energy storage element including a container, The storage element is an electrode terminal having a terminal body disposed outside the container and a shaft body connected to the terminal body and disposed so as to penetrate a wall portion of the container; an insulating member disposed between the terminal body and the wall of the container, The manufacturing method is an arrangement step of arranging a first seal portion and a second seal portion, the first seal portion and the second seal portion being aligned in a radial direction of the shaft body and extending in a circumferential direction of the shaft body, at least one between the terminal body and the insulating member and between the insulating member and the wall portion; a compressing step of pressing the terminal body toward the wall portion to compress the first seal portion and the second seal portion arranged in the arranging step in the axial direction of the shaft body, The second seal portion is formed of a material that is more flexible than the material that forms the first seal portion. A method for manufacturing an energy storage element.

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