Energy storage device and method for manufacturing same

Abstract

The invention provides a power storage device and a method for manufacturing the same. An energy storage element (10) is provided with a positive electrode terminal (200), an electrode body (700), and a positive electrode collector (600) that connects the positive electrode terminal (200) and the electrode body (700), and the positive electrode collector (600) has: a terminal connection part (602) that is connected to the positive electrode terminal (200); an electrode connection part (603) connected to the electrode body (700) in the first direction; and an intermediate section (604) connecting the terminal connection section (602) and the electrode connection section (603), the intermediate section (604) being disposed at a position overlapping the terminal connection section (602) when viewed from the first direction, and the electrode connection section (603) and the terminal connection section (602) being disposed on one side of the intermediate section (604) in the first direction.

Description

[0001] This application is a divisional application of the invention patent application with the application date of October 4, 2019, application number 201980063753.8, and invention name “Electrical storage element and its manufacturing method”. Technical Field

[0002] The present invention relates to an electric storage element and a method for manufacturing the same. The electric storage element includes an electrode terminal, an electrode body, and a current collector connecting the electrode terminal and the electrode body. Background Art

[0003] In the past, it is widely known that there is an electric storage element having an electrode terminal, an electrode body, and a current collector connecting the electrode terminal and the electrode body. Patent document 1 discloses the following secondary battery (electric storage element), which comprises: an electrode terminal; a plurality of electrode plates (electrode bodies); and a plurality of stacked connecting plates (current collectors), both ends of which are joined to the electrode terminal and the plurality of electrode plates to electrically connect the electrode terminal and the plurality of electrode plates, and the plurality of stacked connecting plates are folded into a curved shape between the electrode terminal and the plurality of electrode plates.

[0004] Prior Art Literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2011-165475 Summary of the invention

[0007] Problems to be solved by the invention

[0008] However, in the above-mentioned conventional power storage device, there is a concern that the energy density may decrease.

[0009] An object of the present invention is to provide an electric storage device capable of improving energy density and a method for manufacturing the same.

[0010] Means for solving problems

[0011] One embodiment of the present invention involves a storage element comprising an electrode terminal, an electrode body and a collector connecting the electrode terminal and the electrode body, the collector having: a terminal connecting portion connected to the electrode terminal; an electrode connecting portion connected to the electrode body in a first direction; and an intermediate portion connecting the terminal connecting portion and the electrode connecting portion, the intermediate portion being arranged at a position overlapping with the terminal connecting portion when viewed from the first direction, and the electrode connecting portion and the terminal connecting portion being arranged on one side of the intermediate portion in the first direction.

[0012] The present invention can be realized not only as such an electric storage element but also as a current collector provided in the electric storage element, a current collector and a restricting portion, or a method for manufacturing the same.

[0013] Effects of the Invention

[0014] According to the present invention, it is possible to provide an electric storage element and the like capable of achieving improved energy density. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a perspective view showing the appearance of the electric storage element according to the embodiment.

[0016] Figure 2 This is an exploded perspective view showing each component by disassembling the power storage device according to the embodiment.

[0017] Figure 3 It is a perspective view and a front view which show the structure of the positive electrode current collector concerning embodiment.

[0018] Figure 4 It is a perspective view showing a connection structure among a positive electrode current collector, a positive electrode terminal, and an electrode body according to an embodiment.

[0019] Figure 5 It is a diagram for explaining the method for manufacturing the electric storage element according to the embodiment (the step of bending the positive electrode current collector).

[0020] Figure 6 It is a perspective view showing a connection structure among a positive electrode current collector, a positive electrode terminal, and an electrode body according to Modification 1 of the embodiment.

[0021] Figure 7 It is a perspective view and a front view showing the structure of a positive electrode current collector according to Modification 2 of the embodiment. DETAILED DESCRIPTION

[0022] In the above-mentioned conventional storage element, there is a concern that the energy density may decrease. That is, in the above-mentioned conventional storage element, the electrode terminal and the electrode body are connected by folding the collector into a curved shape, so that the electrode body is arranged at a position away from the electrode terminal. As a result, the size of the electrode body is limited, and the energy density decreases.

[0023] One embodiment of the present invention involves a storage element, which is a storage element comprising an electrode terminal, an electrode body, and a collector connecting the electrode terminal to the electrode body, wherein the collector has: a terminal connecting portion connected to the electrode terminal; an electrode connecting portion connected to the electrode body in a first direction; and an intermediate portion connecting the terminal connecting portion and the electrode connecting portion, the intermediate portion being arranged at a position overlapping with the terminal connecting portion when viewed from the first direction, and the electrode connecting portion and the terminal connecting portion being arranged on one side of the intermediate portion in the first direction.

[0024] Thus, in the storage element, the collector has a terminal connection portion, an electrode connection portion and a middle portion, the middle portion is arranged at a position overlapping with the terminal connection portion when viewed from the first direction, and the electrode connection portion and the terminal connection portion are arranged on one side of the middle portion in the first direction. In the case where the middle portion is arranged overlapping with the terminal connection portion when viewed from the first direction, there is a concern that the electrode connection portion is arranged away from the terminal connection portion in the first direction. If the electrode connection portion is arranged away from the terminal connection portion in the first direction, the electrode body is arranged at a position away from the electrode terminal in the first direction, so that the size of the electrode body is limited. Therefore, the electrode connection portion and the terminal connection portion are arranged on one side of the middle portion in the first direction. Thus, since the electrode body can be close to the electrode terminal in the first direction, a larger electrode body can be arranged, thereby achieving an increase in energy density.

[0025] The electrode connecting portion may be arranged at a position that does not overlap with the terminal connecting portion when viewed from the first direction.

[0026] Thus, in the current collector, the electrode connection portion is arranged at a position that does not overlap with the terminal connection portion when viewed from the first direction. In this way, by arranging the electrode connection portion at a position that does not overlap with the terminal connection portion when viewed from the first direction, the electrode connection portion can be close to the terminal connection portion in the first direction. Therefore, since the electrode body can be close to the electrode terminal in the first direction, a larger electrode body can be arranged, thereby achieving an increase in energy density.

[0027] The electrode connection portion may be arranged in a second direction of the intermediate portion intersecting the first direction, and the intermediate portion may be connected to an end of the terminal connection portion in a third direction intersecting the first direction and the second direction.

[0028] Thus, in the current collector, the electrode connection portion is arranged in the second direction of the middle portion, and the middle portion is connected to the end portion of the terminal connection portion in the third direction. By arranging the electrode connection portion in the second direction of the middle portion in this way, the portion of the electrode connection portion that does not overlap with the middle portion when viewed from the first direction can be close to the terminal connection portion in the first direction. Therefore, since the electrode body can be close to the electrode terminal in the first direction, a larger electrode body can be arranged. By connecting the middle portion to the end portion of the terminal connection portion in the third direction, it is sometimes easy to connect the electrode connection portion to the electrode body. Thus, the connection between the current collector and the electrode body can be easy, and an increase in energy density can be achieved.

[0029] The intermediate portion may include a bent portion bent or curved toward the electrode connecting portion in a portion connected to the electrode connecting portion, and the bent portion may be arranged at a position overlapping the terminal connecting portion when viewed from the first direction.

[0030] Thus, in the current collector, the middle portion has a bent portion at the connection portion with the electrode connection portion, and the bent portion is arranged at a position overlapping with the terminal connection portion. In this way, by overlapping the bent portion of the middle portion with the terminal connection portion, the middle portion becomes a shape bent from the position of the terminal connection portion, thereby increasing the size of the electrode connection portion. Thus, the electrode body can be connected to a larger electrode connection portion, thereby enabling the electrode body and the current collector to be connected more stably.

[0031] The device may further include a restricting portion that restricts at least one of the electrode connecting portion and the intermediate portion from moving in the first direction in a direction away from the terminal connecting portion.

[0032] Thus, the storage element includes a restriction portion that restricts at least one of the electrode connection portion and the middle portion of the collector from being separated from the terminal connection portion in the first direction. Thus, by restricting at least one of the electrode connection portion and the middle portion from being separated from the terminal connection portion in the first direction, it is possible to suppress the electrode body from being separated from the electrode terminal in the first direction. Thus, the electrode body can be brought close to the electrode terminal in the first direction, so that a larger electrode body can be configured, and an increase in energy density can be achieved.

[0033] A method for manufacturing an energy storage element involved in one embodiment of the present invention is a method for manufacturing an energy storage element, the energy storage element comprising an electrode terminal, an electrode body, and a collector connecting the electrode terminal to the electrode body, the collector comprising: a terminal connecting portion connected to the electrode terminal; an electrode connecting portion connected to the electrode body in a first direction; and an intermediate portion connecting the terminal connecting portion and the electrode connecting portion, the method for manufacturing an energy storage element comprising: a bending step of bending the collector so that the intermediate portion is arranged at a position overlapping with the terminal connecting portion when viewed from the first direction, and the electrode connecting portion and the terminal connecting portion are arranged on one side of the intermediate portion in the first direction.

[0034] Thus, in the method for manufacturing the storage element, in the bending step, the current collector is bent so that the middle portion of the current collector is arranged at a position overlapping with the terminal connection portion of the current collector, and the electrode connection portion and the terminal connection portion of the current collector are arranged on one side of the middle portion in the first direction. By arranging the electrode connection portion on the one side of the middle portion, the electrode body can be brought closer to the electrode terminal, so that a larger electrode body can be arranged, and the energy density can be improved.

[0035] Alternatively, in the bending step, the collector is bent through two stages in the order of a first bending step and a second bending step, wherein in the first bending step, at least one of the electrode connecting portion and the middle portion is supported from both sides of the first direction, and the terminal connecting portion is brought closer to the middle portion, and in the second bending step, at least one of the electrode connecting portion and the middle portion is supported from the side opposite to the terminal connecting portion in the first direction, and the terminal connecting portion is brought further closer to the middle portion.

[0036] Thus, in the bending step, the current collector is bent in two stages in the order of the first bending step and the second bending step, so that the current collector can be efficiently bent. Thus, a power storage element capable of achieving improved energy density can be easily manufactured.

[0037] Hereinafter, the storage element involved in the embodiment (and its variant) of the present invention will be described with reference to the accompanying drawings. The embodiments described below all show general or specific examples. The numerical values, shapes, materials, components, configuration positions of components and connection methods, manufacturing processes, and the order of manufacturing processes shown in the following embodiments are examples, and their purpose is not to limit the present invention. In each figure, the dimensions, etc. are not strictly illustrated.

[0038] In the following description and drawings, the arrangement direction of a pair of (positive side and negative side) electrode terminals of the storage element, the arrangement direction of a pair of collectors, the arrangement direction of a pair of sheet bundles of the electrode body, or the opposing direction of the short side of the container is defined as the X-axis direction. The opposing direction of the long side of the container, the short side direction of the short side of the container, the thickness direction of the container, or the stacking direction of the electrode plates of the electrode body is defined as the Y-axis direction. The arrangement direction of the electrode terminals, collectors and electrode bodies, the arrangement direction of the container body and the cover of the storage element, the long side direction or the up and down direction of the short side of the container are defined as the Z-axis direction. These X-axis directions, Y-axis directions and Z-axis directions are directions that intersect each other (orthogonal in this embodiment). Depending on the usage, the situation where the Z-axis direction does not become the up and down direction is also considered, but for the sake of convenience of explanation, the Z-axis direction is described as the up and down direction. In the following description, the so-called positive side of the X-axis direction refers to the side of the arrow direction of the X-axis, and the so-called negative side of the X-axis direction refers to the side opposite to the positive side of the X-axis direction. The same is true for the Y-axis direction and the Z-axis direction.

[0039] (Implementation Method)

[0040] [1. General description of the energy storage element]

[0041] First, the overall description of the electric storage element 10 in this embodiment will be given. Figure 1It is a perspective view showing the appearance of the electric storage element 10 according to the present embodiment. Figure 2 This is an exploded perspective view showing each component by disassembling the electric storage device 10 according to the present embodiment.

[0042] The storage element 10 is a secondary battery capable of charging and discharging electric power, specifically, a non-aqueous electrolyte secondary battery such as a lithium ion secondary battery. The storage element 10 can be used as a battery for driving or starting an engine of a mobile body such as an electric vehicle (EV), a hybrid electric vehicle (HEV), or a plug-in hybrid electric vehicle (PHEV), a motorcycle, a watercraft, a snowmobile, an agricultural machine, a construction machine, etc.

[0043] The 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 may be a capacitor. The storage element 10 may not be a secondary battery, but a primary battery that can use the stored electricity even if the user does not charge it. Furthermore, the storage element 10 may also be a battery using a solid electrolyte. In the present embodiment, a storage element 10 in a rectangular shape (angular shape) is illustrated, but the shape of the storage element 10 is not limited to a rectangular shape, but may be a polygonal prism shape, a cylindrical shape, a long cylindrical shape, etc. other than a rectangular shape, and may also be a laminated storage element.

[0044] like Figure 1 As shown in FIG. 1 , the electric storage element 10 includes a container 100, a positive electrode terminal 200, a negative electrode terminal 210, a positive electrode upper gasket 300, and a negative electrode upper gasket 310. Figure 2 As shown, inside the container 100, a positive electrode lower gasket 400, a negative electrode lower gasket 500, a positive electrode collector 600, a negative electrode collector 610 and an electrode body 700 are housed. An electrolyte (non-aqueous electrolyte) is sealed inside the container 100, but it is omitted and illustrated. As the electrolyte, there is no particular restriction on its type as long as it does not damage the performance of the storage element 10, and various electrolytes can be selected. In addition to the above-mentioned components, a spacer arranged on the side or above the electrode body 700, or an insulating film that wraps the electrode body 700, etc. can also be configured.

[0045] The container 100 is a rectangular parallelepiped (box-shaped) box body, which is composed of a rectangular cylindrical container body 110 having a bottom and a cover body 120 as a plate-shaped member that blocks the opening of the container body 110. The container 100 is a structure capable of sealing the inside by welding the container body 110 and the cover body 120 after accommodating the electrode body 700 and the like. The material of the container 100 is not particularly limited, but is preferably a weldable metal such as stainless steel, aluminum, aluminum alloy, iron, and plated steel plate.

[0046] The lid 120 is provided with a gas discharge valve 121, and the gas discharge valve 121 discharges the gas inside the container 100 when the internal pressure of the container 100 increases. The container 100 may be provided with a liquid injection portion for injecting an electrolyte into the interior.

[0047] The electrode body 700 includes a positive electrode plate, a negative electrode plate, and a separator, and is an electricity storage element (power generation element) capable of storing electricity. The positive electrode plate has a flat and rectangular positive electrode collector foil made of aluminum or an aluminum alloy, and a positive electrode active material layer formed on the surface of the positive electrode collector foil. The negative electrode plate has a flat and rectangular negative electrode collector foil made of copper or a copper alloy, and a negative electrode active material layer formed on the surface of the negative electrode collector foil. The positive electrode active material and the negative electrode active material used as the positive electrode active material layer and the negative electrode active material layer can be any active material that can absorb and release lithium ions, and known materials can be used appropriately.

[0048] The positive electrode collector foil and the negative electrode collector foil both have rectangular tabs protruding upward (positive side in the Z-axis direction). Multiple positive plates and multiple negative plates are stacked with separators sandwiched between them, so that multiple tabs are stacked on the positive plates and the negative plates. As a result, a tab bundle 710 on the positive electrode side and a tab bundle 720 on the negative electrode side are formed on the electrode body 700.

[0049] Regarding the positive plate and the negative plate, it is set to have a rectangular shape, but the shape of the positive plate and the negative plate is not limited to a rectangular shape, and can also be a polygonal shape other than a rectangular shape, an oblong shape, an oblong shape, etc. For the tabs of the positive plate and the negative plate, it is not limited to a rectangular shape, and any shape other than a rectangular shape, a polygonal shape, a semicircular shape, a semi-oblong shape, a semi-elliptical shape, etc. can be used. The stacked positive plate and the negative plate can be fixed by arranging an insulating tape around the electrode body 700 or on both sides of the X-axis direction, and sandwiching the stacked positive plate and the negative plate in the stacking direction (Y-axis direction). Alternatively, the positive plate and the negative plate can be fixed in the stacking direction by hot pressing, etc.

[0050] The positive terminal 200 is an electrode terminal electrically connected to the positive electrode plate of the electrode body 700 via the positive electrode collector 600. The negative terminal 210 is an electrode terminal electrically connected to the negative electrode plate of the electrode body 700 via the negative electrode collector 610. That is, the positive terminal 200 and the negative terminal 210 are metal electrode terminals for leading out the electricity stored in the electrode body 700 to the external space of the storage element 10, and for introducing electricity into the internal space of the storage element 10 in order to store electricity in the electrode body 700. The positive terminal 200 and the negative terminal 210 are connected to the positive electrode collector 600 and the negative electrode collector 610 by caulking or the like, and are mounted on the cover 120.

[0051] Specifically, the positive terminal 200 has a cylindrical shaft portion 201 (rivet portion) extending downward (negative side in the Z-axis direction). The shaft portion 201 is inserted into the circular through hole 301 of the positive upper gasket 300, the circular through hole 123 of the cover 120, the circular through hole 401 of the positive lower gasket 400, and the circular through hole 601 of the positive collector 600 and riveted. Thus, the positive terminal 200 is fixed to the cover 120 together with the positive upper gasket 300, the positive lower gasket 400 and the positive collector 600. The same is true for the negative side. The positive terminal 200 and the negative terminal 210 are formed of aluminum, aluminum alloy, copper or copper alloy.

[0052] The positive electrode collector 600 is a flat conductive member that electrically connects the positive electrode plate of the electrode body 700 and the positive terminal 200. The negative electrode collector 610 is a flat conductive member that electrically connects the negative electrode plate of the electrode body 700 and the negative terminal 210. Specifically, the positive electrode collector 600 is joined to the tab bundle 710 on the positive electrode side of the electrode body 700 by welding or the like, and is joined to the positive terminal 200 by riveting or the like as described above. The negative electrode collector 610 is joined to the tab bundle 720 on the negative electrode side of the electrode body 700 by welding or the like, and is joined to the negative terminal 210 by riveting or the like as described above. The positive electrode collector 600 is formed of aluminum or an aluminum alloy or the like, and the negative electrode collector 610 is formed of copper or a copper alloy or the like.

[0053] The positive electrode collector 600 and the negative electrode collector 610 are arranged between the electrode body 700 and the cover 120 of the container 100. Specifically, the positive electrode collector 600 is arranged between the tab bundle 710 on the positive electrode side of the electrode body 700 and the positive electrode lower gasket 400, and the negative electrode collector 610 is arranged between the tab bundle 720 on the negative electrode side of the electrode body 700 and the negative electrode lower gasket 500. That is, the positive electrode collector 600 is arranged at a position where the positive electrode lower gasket 400 is sandwiched between the positive electrode collector 600 and the cover 120, and the negative electrode collector 610 is arranged at a position where the negative electrode lower gasket 500 is sandwiched between the positive electrode collector 600 and the cover 120. The detailed description of the structure of the positive electrode collector 600 and the negative electrode collector 610 will be described later.

[0054] The positive electrode upper gasket 300 is a flat plate-shaped electrically insulating sealing member disposed between the cover 120 of the container 100 and the positive electrode terminal 200. The negative electrode upper gasket 310 is a flat plate-shaped electrically insulating sealing member disposed between the cover 120 of the container 100 and the negative electrode terminal 210. Specifically, the positive electrode upper gasket 300 is formed to cover the lower part and the side of the positive electrode terminal 200, and the negative electrode upper gasket 310 is formed to cover the lower part and the side of the negative electrode terminal 210.

[0055] The positive electrode lower gasket 400 is a flat plate-shaped electrically insulating sealing member disposed between the lid 120 and the positive electrode current collector 600 . The negative electrode lower gasket 500 is a flat plate-shaped electrically insulating sealing member disposed between the lid 120 and the negative electrode current collector 610 .

[0056] The positive electrode upper gasket 300, the negative electrode upper gasket 310, the positive electrode lower gasket 400 and the negative electrode lower gasket 500 are formed of resins such as polypropylene (PP), polyethylene (PE), polyphenylene sulfide resin (PPS), polyethylene terephthalate (PET), polyetheretherketone (PEEK), tetrafluoroethylene-perfluoroalkylvinyl ether (PFA), polytetrafluoroethylene (PTFE), polybutylene terephthalate (PBT), polyethersulfone (PES) and their composite materials.

[0057] [2. Description of the Structure of the Positive Electrode Collector and the Negative Electrode Collector]

[0058] Next, the structures of the positive electrode collector 600 and the negative electrode collector 610 are described in detail. The positive electrode collector 600 and the negative electrode collector 610 have the same structure (a shape symmetrical with respect to the YZ plane), so the positive electrode collector 600 is described in detail below, and the description of the negative electrode collector 610 is simplified or omitted.

[0059] Figure 3 1 is a perspective view and a front view showing the structure of the positive electrode current collector 600 according to the present embodiment. Specifically, Figure 3 (a) is a perspective view of the positive electrode current collector 600 when viewed from obliquely above. Figure 2 The positive electrode current collector 600 is shown in an enlarged perspective view. Figure 3 (b) is viewed from the negative side of the Y axis Figure 3 (a) is a front view of a positive electrode current collector 600 . Figure 4 2 is a perspective view showing the connection structure of the positive electrode current collector 600, the positive electrode terminal 200, and the electrode body 700 according to the present embodiment. Specifically, Figure 4 (a) is a perspective view of the structure in a state where the terminal connection portion 602 of the positive electrode current collector 600 and the positive electrode terminal 200 are connected, as seen from obliquely below. Figure 4 (b) is a perspective view of the structure in a state where the electrode connecting portion 603 of the positive electrode current collector 600 and the tab bundle 710 of the electrode body 700 are connected, as viewed from obliquely below. Figure 4 In (b), the electrode body 700 is omitted in the illustration for convenience of description.

[0060] The positive electrode current collector 600 is a member having one end connected to the positive electrode terminal 200 and the other end connected to the electrode body 700. Figure 3 As shown, the positive electrode current collector 600 includes a terminal connection portion 602 connected to the positive electrode terminal 200, an electrode connection portion 603 connected to the electrode body 700, and an intermediate portion 604 disposed between the terminal connection portion 602 and the electrode connection portion 603. That is, the positive electrode current collector 600 including the terminal connection portion 602, the intermediate portion 604, and the electrode connection portion 603 is formed by bending a single L-shaped flat plate member.

[0061] The terminal connection portion 602 is a rectangular and flat plate-shaped portion connected (joined) to the positive terminal 200 by riveting or the like, and is arranged parallel to the XY plane. That is, as described above, the terminal connection portion 602 has a through hole 601, and the shaft portion 201 of the positive terminal 200 is inserted into the through hole 601 in a state of being oriented in the Z-axis direction (hereinafter also referred to as the first direction) (facing the Z-axis direction). Figure 4 As shown in (a), the end of the shaft portion 201 on the negative side in the Z-axis direction is riveted to form a riveted portion 201a, and the positive terminal 200 and the terminal connecting portion 602 are joined in the Z-axis direction. The method of connecting (joining) the terminal connecting portion 602 and the positive terminal 200 is not limited to riveting, and welding such as ultrasonic bonding, laser welding, resistance welding, or mechanical bonding other than riveting such as screw fastening may also be used.

[0062] return Figure 3 The electrode connection portion 603 is a rectangular and flat plate-shaped portion connected (joined) to the tab bundle 710 of the electrode body 700 by welding or the like, and is arranged parallel to the XY plane. Figure 4 In the state where the middle portion 604 and the electrode connection portion 603 shown in (a) are oriented in the Y-axis direction (facing the Y-axis direction), the tab bundle 710 (not shown) of the electrode body 700 is joined to the electrode connection portion first surface 603a, which is the surface on the positive side in the Y-axis direction of the electrode connection portion 603, by welding. The welding is performed in a state where the tab bundle 710 is sandwiched between the electrode connection portion first surface 603a and the abutment plate (not shown). Figure 4 As shown in (b), the middle portion 604 and the electrode connecting portion 603 are bent toward the negative side in the Y-axis direction. Thus, the first surface 603a of the electrode connecting portion becomes the surface on the negative side in the Z-axis direction, and the electrode connecting portion 603 becomes a structure that is connected to the tab bundle 710 of the electrode body 700 in the Z-axis direction (first direction) in a state of being oriented in the Z-axis direction (facing the Z-axis direction).

[0063] In other words, the tab bundle 710 of the electrode body 700 is bonded to the first surface 603a of the electrode connecting portion in a state of extending in the Z-axis direction, and after bonding, it is bent in the Y-axis direction to be in a state of extending in the Y-axis direction. As for the method of connecting (bonding) the electrode connecting portion 603 and the tab bundle 710 of the electrode body 700, any welding method such as ultrasonic bonding, laser welding, resistance welding, etc. can be used, and mechanical bonding such as riveting bonding or screw fastening can also be used.

[0064] return Figure 3 The middle portion 604 is a roughly rectangular and flat plate-shaped portion connecting the terminal connection portion 602 and the electrode connection portion 603, and is arranged parallel to the XY plane. Specifically, the middle portion 604 is arranged on the negative side of the terminal connection portion 602 in the Z-axis direction and on the negative side of the electrode connection portion 603 in the X-axis direction. That is, the middle portion 604 is arranged at a position overlapping with the terminal connection portion 602 when viewed from the Z-axis direction (first direction), and is arranged to be parallel to the electrode connection portion 603 in the X-axis direction. The middle portion 604 has a connection portion 605 with the terminal connection portion 602 and a connection portion 606 with the electrode connection portion 603.

[0065] The connection part 605 is a part that is connected to the end of the positive side of the Y-axis direction of the terminal connection part 602, is bent to the positive side of the Y-axis direction into a convex shape, and has a U-shaped cross-sectional shape in the YZ plane. That is, as described above, the connection part 605 is a bent part formed by bending the middle part 604 relative to the terminal connection part 602, and is formed to be thinner than other parts of the middle part 604 and the terminal connection part 602, so that it is easy to bend. Specifically, the middle part 604 is bent relative to the terminal connection part 602 to the negative side of the Z-axis direction and the negative side of the Y-axis direction to form the connection part 605. Thus, the middle part 604 is connected to the end of the positive side of the Y-axis direction (hereinafter also referred to as the third direction) of the terminal connection part 602, and is arranged on the negative side of the Z-axis direction of the terminal connection part 602. The connection part 605 may also be a part that is not bent but bent.

[0066] The connection portion 606 is a portion that is connected to the end portion of the electrode connection portion 603 on the negative side in the X-axis direction, is oriented toward the negative side in the X-axis direction and is inclined toward the negative side in the Z-axis direction, and has a substantially S-shaped cross-sectional shape in the XZ plane. That is, the connection portion 606 is an inclined portion formed by bending the middle portion 604 twice toward the negative side in the Z-axis direction and the negative side in the X-axis direction relative to the electrode connection portion 603. Thus, the middle portion 604 is disposed on the negative side in the X-axis direction and the negative side in the Z-axis direction of the electrode connection portion 603.

[0067] In other words, the electrode connection portion 603 is arranged on the positive side of the middle portion 604 in the X-axis direction (hereinafter also referred to as the second direction). Specifically, the electrode connection portion 603 is arranged at a position closer to the positive side in the X-axis direction than the middle portion 604 and the terminal connection portion 602. That is, the electrode connection portion 603 is arranged at a position that does not overlap with the middle portion 604 and the terminal connection portion 602 when viewed from the Z-axis direction (first direction). The electrode connection portion 603 and the terminal connection portion 602 are arranged on one side of the middle portion 604 in the Z-axis direction (first direction) (positive side in the Z-axis direction). It can also be said that the electrode connection portion 603 is arranged at a position closer to the terminal connection portion 602 side than the middle portion 604 in the Z-axis direction (first direction). That is, the electrode connection portion 603 is arranged at a position closer to the terminal connection portion 602 or the cover 120 (or closer to the positive electrode lower gasket 400) than the middle portion 604 in the Z-axis direction (first direction). In the present embodiment, the electrode connection portion 603 is arranged at the same position as the terminal connection portion 602 in the Z-axis direction.

[0068] Specifically, the electrode connection portion first surface 603a of the electrode connection portion 603, which is the surface on the negative side in the Z-axis direction, is arranged at a position closer to the positive side in the Z-axis direction than the middle portion first surface 604a, which is the surface on the negative side in the Z-axis direction, of the middle portion 604. That is, the electrode connection portion first surface 603a and the terminal connection portion first surface 602a, which is the surface on the negative side in the Z-axis direction, of the terminal connection portion 602 are arranged on the same plane (at the same position in the Z-axis direction). The electrode connection portion second surface 603b, which is the surface on the positive side in the Z-axis direction, of the electrode connection portion 603 and the terminal connection portion second surface 602b, which is the surface on the positive side in the Z-axis direction, of the terminal connection portion 602 are arranged on the same plane (at the same position in the Z-axis direction).

[0069] Alternatively, the electrode connection portion 603 may be arranged closer to the negative side in the Z-axis direction or the positive side in the Z-axis direction than the terminal connection portion 602, thereby arranging the first surface 603a of the electrode connection portion at a position closer to the negative side in the Z-axis direction or the positive side in the Z-axis direction than the first surface 602a of the terminal connection portion. Alternatively, the electrode connection portion 603 may have a thickness different from that of the terminal connection portion 602, thereby arranging the first surface 603a of the electrode connection portion at a position closer to the negative side in the Z-axis direction or the positive side in the Z-axis direction than the first surface 602a of the terminal connection portion. Similarly, the second surface 603b of the electrode connection portion may also be arranged at a position closer to the negative side in the Z-axis direction or the positive side in the Z-axis direction than the second surface 602b of the terminal connection portion.

[0070] Next, a method for manufacturing the energy storage device 10 (a step of bending the positive electrode current collector 600 ) will be described. Figure 5 1 is a diagram for explaining a method for manufacturing the electric storage element 10 according to the present embodiment (a step of bending the positive electrode current collector 600 ). Specifically, Figure 5(a) is a side view showing the state before the positive electrode current collector 600 is bent, Figure 5 (b) is a side view showing a state where the positive electrode current collector 600 is being folded. Figure 5 (c) is a side view showing a state where the positive electrode current collector 600 is bent. In the above, the Z-axis direction is also referred to as the first direction, but in Figure 5 In the bending step of the positive electrode current collector 600 shown in FIG. 1 , the Y-axis direction is also referred to as the first direction. Figure 5 In the figure, for convenience of explanation, illustration of the positive electrode terminal 200, the positive electrode upper gasket 300, and the positive electrode lower gasket 400 are omitted, and the cover 120, the positive electrode collector 600, and the electrode body 700 are schematically shown.

[0071] like Figure 5 As shown in (a), the terminal connection part 602 of the positive electrode current collector 600 is joined to the cover 120, and the electrode connection part 603 is joined to the tab bundle 710 of the electrode body 700, in a state where the terminal connection part 602 is orthogonal to the electrode connection part 603 and the middle part 604. In this state, as a first bending process, at least one of the electrode connection part 603 and the middle part 604 is supported from both sides in the Y-axis direction (first direction), and the terminal connection part 602 is brought close to the middle part 604. In this embodiment, the middle part 604 is supported by pressing a force F1 from both sides in the Y-axis direction by a clamp or the like. The terminal connection part 602 is pressed toward the negative side in the Z-axis direction by a force F2, thereby bending the connection part 605, thereby rotating the terminal connection part 602 around the connection part 605, and bringing it close to the middle part 604. The electrode connecting portion 603 may be supported from both sides in the Y-axis direction instead of the intermediate portion 604 or in addition to the intermediate portion 604 .

[0072] In this way, Figure 5 As shown in (b), the connection part 605 is bent until the amount of springback caused by the connection part 605 exceeds the peak value, so that the terminal connection part 602 is rotated by 50° to 70°, and the terminal connection part 602 is close to the middle part 604. Thereafter, as a second bending process, at least one of the electrode connection part 603 and the middle part 604 is supported from the side opposite to the terminal connection part 602 in the Y-axis direction (first direction), and the terminal connection part 602 is further close to the middle part 604. In this embodiment, the middle part 604 is supported by a force F3 from the positive side in the Y-axis direction by a clamp or the like. The terminal connection part 602 is pressed toward the positive side in the Y-axis direction by a force F4, thereby further bending the connection part 605, thereby rotating the terminal connection part 602 around the connection part 605, and further approaching the middle part 604. The electrode connection part 603 may be supported from the positive side in the Y-axis direction instead of the middle part 604 or in addition to the middle part 604.

[0073] Therefore, if Figure 5 As shown in (c), the terminal connection portion 602 is in a state facing the Y-axis direction (facing the Y-axis direction), in other words, in a state parallel to the electrode connection portion 603 and the middle portion 604. In this state, the middle portion 604 is arranged at a position overlapping with the terminal connection portion 602 when viewed from the Y-axis direction, and the electrode connection portion 603 and the terminal connection portion 602 are arranged on one side of the middle portion 604 in the Y-axis direction (negative side in the Y-axis direction). That is, in the bending process, the positive electrode collector 600 is bent in two stages in the order of the first bending process and the second bending process. In this bending process, the positive electrode collector 600 is bent so that the middle portion 604 is arranged at a position overlapping with the terminal connection portion 602 when viewed from the Y-axis direction (first direction), and the electrode connection portion 603 and the terminal connection portion 602 are arranged on one side of the middle portion 604 in the Y-axis direction (first direction) (negative side in the Y-axis direction). It can be said that the positive electrode current collector 600 is bent so that the electrode connecting portion 603 is arranged closer to the terminal connecting portion 602 than the intermediate portion 604 in the Y-axis direction (first direction).

[0074] Afterwards, the positive electrode current collector 600 and the cover 120 are turned toward the positive side in the Y-axis direction (the tab bundle 710 is bent), and become as shown in FIG. Figure 4 In this way, the positive electrode current collector 600 changes from a state facing the Y axis direction to a state facing the Z axis direction, and the definition of the first direction also changes from the Y axis direction to the Z axis direction. The forces F1 to F4 mentioned above can be of any value as long as they can bend the positive electrode current collector 600 as described above, and can be appropriately determined according to the material of the positive electrode current collector 600, etc.

[0075] [3. Description of the Effect]

[0076] As described above, according to the energy storage element 10 according to the embodiment of the present invention, the positive electrode current collector 600 includes the terminal connection portion 602, the electrode connection portion 603, and the middle portion 604, the middle portion 604 is arranged at a position overlapping with the terminal connection portion 602 when viewed from the first direction (Z-axis direction), and the electrode connection portion 603 and the terminal connection portion 602 are arranged on one side of the middle portion 604 in the first direction. In the case where the middle portion 604 is arranged to overlap with the terminal connection portion 602 when viewed from the first direction, there is a concern that the electrode connection portion 603 is arranged away from the terminal connection portion 602 in the first direction. If the electrode connection portion 603 is arranged away from the terminal connection portion 602 in the first direction, the electrode body 700 is arranged at a position away from the positive terminal 200 in the first direction, and the size of the electrode body 700 is limited. Therefore, the electrode connection portion 603 and the terminal connection portion 602 are arranged on one side of the middle portion 604 in the first direction. Thus, the electrode body 700 can be brought closer to the positive electrode terminal 200 in the first direction, so that a larger electrode body 700 can be arranged, and the energy density can be improved.

[0077] In the positive electrode current collector 600, the electrode connection portion 603 is arranged at a position that does not overlap with the terminal connection portion 602 when viewed from the first direction. In this way, by arranging the electrode connection portion 603 at a position that does not overlap with the terminal connection portion 602 when viewed from the first direction, the electrode connection portion 603 can be close to the terminal connection portion 602 in the first direction. Therefore, the electrode body 700 can be close to the positive terminal 200 in the first direction, so that a larger electrode body 700 can be arranged, and the energy density can be improved.

[0078] In the positive electrode current collector 600, the electrode connection portion 603 is arranged in the second direction (positive side in the X-axis direction) of the middle portion 604, and the middle portion 604 is connected to the end portion in the third direction (positive side in the Y-axis direction) of the terminal connection portion 602. In this way, by arranging the electrode connection portion 603 in the second direction of the middle portion 604, the portion of the electrode connection portion 603 that does not overlap with the middle portion 604 when viewed from the first direction can be close to the terminal connection portion 602 in the first direction. Therefore, the electrode body 700 can be close to the positive terminal 200 in the first direction.

[0079] By connecting the middle portion 604 to the end of the terminal connection portion 602 in the third direction, the electrode connection portion 603 can be easily connected to the electrode body 700. That is, if the middle portion 604 is connected to the end of the terminal connection portion 602 on the negative side in the X-axis direction, when the tab bundle 710 of the electrode body 700 is connected to the electrode connection portion 603 in a state where the middle portion 604 is opened 90° in an L shape relative to the terminal connection portion 602, it is necessary to twist the tab bundle 710 by 90°. In contrast, by connecting the middle portion 604 to the end of the terminal connection portion 602 in the third direction, it is not necessary to twist the tab bundle 710 by 90° even when the middle portion 604 is opened relative to the terminal connection portion 602, so that the tab bundle 710 can be easily connected to the electrode connection portion 603. As a result, the connection between the collector 600 and the electrode body 700 can be facilitated, and a larger electrode body 700 can be configured to achieve an increase in energy density.

[0080] The positive electrode current collector 600 has a structure in which a plate-like member is bent, and the position of the electrode connection portion 603 relative to the terminal connection portion 602 can be arbitrarily moved to a certain extent via the intermediate portion 604. Therefore, the position of the electrode connection portion 603 has a high degree of freedom, so that the electrode connection portion 603 and the electrode body 700 can be easily connected. Furthermore, the electrode connection portion 603 can be brought close to the electrode body 700, so that the protruding length of the tab bundle 710 can be shortened. If the protruding length of the tab bundle 710 can be shortened, the space occupied by the tab bundle 710 in the container 100 is reduced, so that a larger electrode body 700 can be configured, and the energy density can be improved.

[0081] In the method for manufacturing the energy storage element 10, in the bending step, the positive electrode current collector 600 is bent so that the middle portion 604 of the positive electrode current collector 600 is arranged at a position overlapping with the terminal connection portion 602 of the positive electrode current collector 600, and the electrode connection portion 603 and the terminal connection portion 602 of the positive electrode current collector 600 are arranged on one side of the middle portion 604 in the first direction. By arranging the electrode connection portion 603 on this side of the middle portion 604, the electrode body 700 can be brought close to the positive terminal 200, so that a larger electrode body 700 can be arranged, and the energy density can be improved.

[0082] In the bending step, the positive electrode current collector 600 is bent in two stages in the order of the first bending step and the second bending step, so that the bending work of the positive electrode current collector 600 can be efficiently performed. Thus, the electric storage element 10 capable of achieving improved energy density can be easily manufactured.

[0083] In the above, the effect of the structure on the positive electrode side (positive electrode current collector 600 side) is described, but the same effect can be achieved with the structure on the negative electrode side (negative electrode current collector 610 side). The same applies to the following contents.

[0084] [4. Description of Modifications]

[0085] (Variant 1)

[0086] Next, Modification 1 of the above-described embodiment will be described. Figure 6 : is a perspective view showing a connection structure of a positive electrode current collector 600, a positive electrode terminal 200, and an electrode body 700 according to Modification 1 of the present embodiment. Specifically, Figure 6 (a) is related to Figure 4 The corresponding figure of (a) is Figure 6 (b) is related to Figure 4 (b) The corresponding figure.

[0087] like Figure 6 As shown, in this modification, a positive electrode lower gasket 400a is provided instead of the positive electrode lower gasket 400 in the above embodiment. Specifically, the positive electrode lower gasket 400a in this modification has a restriction portion 403 in addition to the structure of the positive electrode lower gasket 400 in the above embodiment. The other structures are the same as those in the above embodiment.

[0088] The restricting portion 403 is a portion that restricts at least one of the electrode connecting portion 603 and the intermediate portion 604 of the positive electrode current collector 600 from moving in the direction away from the terminal connecting portion 602 (negative side in the Z-axis direction) in the Z-axis direction (first direction).

[0089] Specifically, Figure 6 As shown in (a), the limiting portion 403 is provided on the surface of the negative side in the Z-axis direction of the portion on the positive side in the X-axis direction of the positive electrode lower gasket 400a, and is a protrusion (hook) protruding toward the negative side in the X-axis direction. Figure 6 As shown in (b), the limiting portion 403 is arranged on the negative side in the Z-axis direction of the end portion on the positive side in the X-axis direction of the electrode connecting portion 603 when the electrode connecting portion 603 and the intermediate portion 604 are bent relative to the terminal connecting portion 602. Thus, the limiting portion 403 is engaged with the end portion on the positive side in the X-axis direction of the electrode connecting portion 603, and limits the movement of the electrode connecting portion 603 in the Z-axis direction (first direction) in the direction away from the terminal connecting portion 602 (negative side in the Z-axis direction).

[0090] The limiting portion 403 may be arranged at the end of the electrode connecting portion 603 on the positive side in the Y-axis direction or the negative side in the Y-axis direction, or may be arranged at the end of the middle portion 604 on the negative side in the X-axis direction or the negative side in the Y-axis direction. Alternatively, the positive electrode lower gasket 400a may have a plurality of limiting portions 403 arranged at the end of any one of them.

[0091] From the viewpoint of effectively limiting the movement of the electrode connection portion 603, the limiting portion 403 is preferably arranged at the end of the electrode connection portion 603 on the positive side in the X-axis direction or the negative side in the Y-axis direction. From the viewpoint of suppressing damage to the splice bundle 710 joined to the electrode connection portion 603, the limiting portion 403 is preferably arranged at the end of the middle portion 604 on the negative side in the X-axis direction or the negative side in the Y-axis direction. From the viewpoint of effectively suppressing the electrode connection portion 603 and the middle portion 604 from opening relative to the terminal connection portion 602, the limiting portion 403 is preferably arranged at the end of the electrode connection portion 603 on the negative side in the Y-axis direction or the negative side in the Y-axis direction of the middle portion 604.

[0092] As described above, according to the storage element involved in this variation, the same effect as the above-mentioned embodiment can be achieved. In particular, the positive electrode lower gasket 400a has a limiting portion 403, and the limiting portion 403 limits at least one of the electrode connection portion 603 and the middle portion 604 of the positive electrode collector 600 to move away from the terminal connection portion 602 in the first direction (Z-axis direction). In this way, by limiting at least one of the electrode connection portion 603 and the middle portion 604 to move away from the terminal connection portion 602 in the first direction, it is possible to suppress the electrode body 700 from moving away from the positive terminal 200 in the first direction. In particular, the positive electrode collector 600 is a structure in which a plate-like member is bent at the connection portion 605, so due to the rebound caused by the connection portion 605, the electrode connection portion 603 and the middle portion 604 are easily moved in a direction away from the terminal connection portion 602. Therefore, it is particularly significant to restrict at least one of the electrode connection part 603 and the middle part 604 from being away from the terminal connection part 602 by the restriction part 403. Thus, the electrode body 700 can be brought closer to the positive terminal 200 in the first direction, so that a larger electrode body 700 can be arranged, and the energy density can be improved.

[0093] The limiting portion 403 may not be a protrusion that engages with at least one of the electrode connecting portion 603 and the middle portion 604, but may be an interlocking portion that interlocks with at least one of the electrode connecting portion 603 and the middle portion 604. The limiting portion 403 may also be provided on the terminal connecting portion 602, the cover 120, or the rivet portion 201a, etc., instead of being provided on the positive electrode lower gasket 400a. The limiting portion 403 may also be an adhesive or double-sided tape that bonds at least one of the electrode connecting portion 603 and the middle portion 604 to the terminal connecting portion 602 or the positive electrode lower gasket 400a, etc., a joint portion of riveting, a fastening portion of screwing, a welding portion of welding, a welding portion of welding, etc.

[0094] (Variant 2)

[0095] Next, a modification 2 of the above-described embodiment will be described. Figure 7 2 is a perspective view and a front view showing the structure of a positive electrode current collector 600a according to a second modification of the present embodiment. Specifically, Figure 7 (a) is the state where the positive electrode current collector 600a is opened, that is, viewed from obliquely below. Figure 4 A stereoscopic diagram of the state shown in (a). Figure 7 (b) is the state where the positive electrode current collector 600a is closed, that is, when viewed from the front Figure 4 The front view of the state shown in (b) is the same as Figure 3 (b) The corresponding figure.

[0096] like Figure 7 As shown in (a), the positive electrode current collector 600a in this modification is different from the positive electrode current collector 600 in the above embodiment, and a concave portion 607 that is recessed toward the negative side in the X-axis direction is formed at the connection portion of the middle portion 604 with the terminal connection portion 602. As a result, the length of the connection portion 605a in the X-axis direction in this modification is shorter than that of the connection portion 605 in the above embodiment. That is, in this modification, compared with the above embodiment, the connection portion 606 and the electrode connection portion 603 are arranged at a position closer to the negative side in the X-axis direction.

[0097] With such a structure, the bent portions 606a and 606b of the connecting portion 606 are also arranged on the negative side in the X-axis direction, so that Figure 7As shown in (b), the bent portion 606a is arranged at a position overlapping with the terminal connection portion 602 when viewed from the Z-axis direction (first direction). The bent portions 606a and 606b are portions that are bent or curved from the middle portion 604 toward the electrode connection portion 603 in the connection portion 606. That is, the bent portion 606a is a portion that is curved on the negative side of the X-axis direction of the connection portion 606, and the bent portion 606b is a portion that is curved on the positive side of the X-axis direction of the connection portion 606. The other structures are the same as those in the above-mentioned embodiment.

[0098] As described above, according to the storage element involved in this modification, the same effect as the above-mentioned embodiment can be achieved. In particular, in the positive electrode collector 600a, the middle part 604 has a bent portion 606a at the connection part 606 with the electrode connection part 603, and the bent portion 606a is arranged at a position overlapping with the terminal connection part 602. In this way, by overlapping the bent portion 606a of the middle part 604 with the terminal connection part 602, the middle part 604 becomes a shape bent from the position of the terminal connection part 602, thereby increasing the size of the electrode connection part 603. As a result, the electrode body 700 can be connected to the larger electrode connection part 603, so that the electrode body 700 and the positive electrode collector 600 can be connected more stably. In this modification, when the electrode connection part 603 is made the same size as the above-mentioned embodiment, the positive electrode collector 600a can be miniaturized, thereby achieving space saving.

[0099] In this modification, the electrode connection portion 603 is configured to be slightly moved to the negative side in the Z-axis direction, and further to the negative side in the X-axis direction, so that the bent portion 606b can also be configured at a position overlapping with the terminal connection portion 602 as viewed from the Z-axis direction. The electrode connection portion 603 can also be further moved to the negative side in the X-axis direction until the electrode connection portion 603 is configured to overlap with the terminal connection portion 602 as viewed from the Z-axis direction. Furthermore, by slightly moving the middle portion 604 to the negative side in the Z-axis direction, the electrode connection portion 603 can also be further moved to the negative side in the X-axis direction until the electrode connection portion 603 is configured to overlap with the middle portion 604 as viewed from the Z-axis direction. In these cases, the electrode connection portion 603 or the middle portion 604 is slightly moved to the negative side in the Z-axis direction, so there is a concern that the size of the electrode body 700 is somewhat limited, but the size of the electrode connection portion 603 can be further increased, and space saving in the X-axis direction can be achieved.

[0100] (Other Modifications)

[0101] The above describes the storage element involved in the embodiment of the present invention and its variant, but the present invention is not limited to the embodiment and its variant. That is, the embodiment and its variant disclosed this time are illustrative in all aspects and are not restrictive. The scope of the present invention is shown by the scope of the request, including the meaning equivalent to the scope of the request and all changes within the scope. The following describes the positive electrode collector, but the same is true for the negative electrode collector 610.

[0102] In the above embodiment and its modified example, the electrode connecting portion 603 of the positive electrode current collector 600, 600a is bent toward the terminal connecting portion 602 after being joined to the tab bundle 710 of the electrode body 700. However, the electrode connecting portion 603 may be joined to the tab bundle 710 in a bent state.

[0103] In the above-mentioned embodiment and its modification, the connection part 605, 605a of the middle part 604 of the positive electrode current collector 600, 600a is connected to the end of the positive side in the Y-axis direction of the terminal connection part 602. However, the connection part 605, 605a may be connected to the end of the negative side in the Y-axis direction or the end of the negative side in the X-axis direction of the terminal connection part 602. However, in the case where the middle part 604 is connected to the end of the negative side in the X-axis direction of the terminal connection part 602, as described above, it sometimes becomes difficult to connect the tab bundle 710 of the electrode body 700 to the electrode connection part 603, and therefore it is preferable that the connection part 605, 605a is connected to the end of the positive side in the Y-axis direction or the end of the negative side in the Y-axis direction of the terminal connection part 602.

[0104] In the above embodiment and its variant, a recess or through hole with the rivet portion 201a disposed inside the middle portion 604 of the positive electrode current collector 600, 600a may be formed. Thus, the middle portion 604 can be brought closer to the terminal connection portion 602, so that a larger electrode body 700 can be disposed, which can improve the energy density.

[0105] In the above-mentioned embodiment and its variation, the electrode body 700 is set to be a stacked electrode body in which a plurality of flat plate-shaped plates are stacked. However, the shape of the electrode body 700 is not particularly limited, and the electrode body 700 may also be a wound electrode body formed by winding a structure in which a separator is sandwiched between a positive plate and a negative plate in a layered manner. The electrode body 700 may also be a corrugated electrode body in which the plate is folded into a corrugated shape. The number of electrode bodies 700 is not limited to one, and two or more may be provided.

[0106] In the above embodiment and its modified example, both the positive electrode side (positive electrode current collector 600, 600a side) and the negative electrode side (negative electrode current collector 610 side) have the above structure. However, the positive electrode side or the negative electrode side may not have the above structure.

[0107] A configuration in which the above-described embodiment and the above-described modified examples are arbitrarily combined is also included in the scope of the present invention.

[0108] The present invention can be realized not only as such an electric storage element but also as a current collector (positive electrode current collector, negative electrode current collector) included in the electric storage element or the current collector and the restricting portion 403 .

[0109] The present invention can be applied to power storage elements such as lithium ion secondary batteries, etc.

[0110] Explanation of symbols

[0111] 10: Storage element;

[0112] 200: positive terminal;

[0113] 201: shaft;

[0114] 201a: riveting part;

[0115] 210: Negative terminal;

[0116] 400, 400a: positive electrode lower gasket;

[0117] 403: Restriction Department;

[0118] 500: negative electrode lower gasket;

[0119] 600, 600a: positive electrode current collector;

[0120] 602: terminal connection portion;

[0121] 602a: first surface of the terminal connection portion;

[0122] 602b: second surface of the terminal connection portion;

[0123] 603: electrode connection part;

[0124] 603a: first surface of the electrode connection portion;

[0125] 603b: second surface of the electrode connection portion;

[0126] 604: middle part;

[0127] 604a: first surface of the middle portion;

[0128] 605, 605a, 606: connecting part;

[0129] 606a, 606b: bending portion;

[0130] 610: negative electrode current collector;

[0131] 700: electrode body;

[0132] 710, 720: splice bundle.

Claims

1. A power storage element comprising an electrode terminal, an electrode body, and a current collector connecting the electrode terminal and the electrode body, wherein: The current collector has: A terminal connecting portion connected to the electrode terminal; An electrode connecting portion connected to the electrode body in a first direction, wherein the first direction is an arrangement direction of the current collector and the electrode body; and an intermediate portion connecting the terminal connection portion and the electrode connection portion, The intermediate portion is arranged at a position overlapping with the terminal connecting portion when viewed from the first direction. The intermediate portion has an intermediate portion first surface on the side opposite to the surface of the intermediate portion facing the terminal connecting portion, A connection position between the electrode body and the electrode connecting portion is located on the opposite side of the electrode body relative to the first surface of the intermediate portion in the first direction.

2. The electric storage element according to claim 1, wherein The terminal connection portion has a terminal connection portion second surface on the opposite side of the surface of the terminal connection portion facing the intermediate portion, The connection position is located between the first surface of the intermediate portion and the second surface of the terminal connection portion in the first direction.

3. The electric storage element according to claim 1 or 2, wherein: The electrode body includes a tab, The contact piece is connected to the electrode connecting portion.

4. The electric storage element according to claim 3, wherein The tab is connected to a surface of the electrode connecting portion that faces the electrode body.

5. The electric storage element according to claim 3 or 4, wherein: The contact piece is arranged at a position that does not overlap with the middle portion when viewed from the first direction.

Images