Method for manufacturing power storage element, and power storage element

Abstract

This manufacturing method of a power storage element comprises a terminal, an electrode body, and a current collector connected to the terminal and the electrode body. The electrode body comprises a body part, and a tab part protruding from the body part. The current collector comprises a terminal connection part connected to the terminal, and an electrode body connection part connected to the tab part. The terminal connection part and the electrode body connection part are arranged in a posture facing in different directions, and are integrally formed. The manufacturing method of the power storage element includes joining the electrode body connection part and the tab part by laser welding.

Description

Electricity storage element manufacturing method and electricity storage element

[0001] The present invention relates to a method for manufacturing an energy storage element and to an energy storage element.

[0002] Patent Document 1 discloses a secondary battery in which a current collecting member has a first current collecting portion and a second current collecting portion, the first current collecting portion being connected to a terminal, and the second current collecting portion being connected to an electrode tab of a wound electrode body.

[0003] JP 2023-94918 A

[0004] In the secondary battery disclosed in Patent Document 1, the second current collecting part is configured separately from the first current collecting part, and multiple electrode tabs and the second current collecting part are overlapped, and then sandwiched between two joining probes from the overlapping direction and joined by applying energy (see paragraph

[0052] and Figure 8, etc., of the specification of Patent Document 1). Therefore, if the second current collecting part is formed integrally with the first current collecting part, there is a risk that joining the second current collecting part and the electrode tabs will be difficult due to a lack of space for joining (such as space for arranging the joining probes).

[0005] The present invention was made by the inventor of the present application by focusing on the above-mentioned problem, and aims to provide a method for manufacturing an energy storage element that can easily join the current collector and the tab portion of the electrode body, and an energy storage element.

[0006] A manufacturing method for a storage element according to one embodiment of the present invention is a manufacturing method for a storage element comprising a terminal, an electrode body, and a current collector connected to the terminal and the electrode body, wherein the electrode body comprises a main body portion and a tab portion protruding from the main body portion, the current collector comprises a terminal connection portion connected to the terminal and an electrode body connection portion connected to the tab portion, the terminal connection portion and the electrode body connection portion are arranged in positions facing in different directions and are integrally formed, and the manufacturing method for the storage element includes joining the electrode body connection portion and the tab portion by laser welding.

[0007] An energy storage element according to one embodiment of the present invention comprises a terminal, an electrode body, and a current collector connected to the terminal and the electrode body, the electrode body comprising a main body portion and a tab portion protruding from the main body portion, the current collector comprising a terminal connection portion connected to the terminal and an electrode body connection portion connected to the tab portion, the terminal connection portion and the electrode body connection portion being arranged in positions facing in different directions and being integrally formed, and the electrode body connection portion and the tab portion being provided with laser welded portions formed by laser welding.

[0008] According to the method for manufacturing an electric storage element of the present invention, the current collector and the tab portion of the electrode assembly can be easily joined.

[0009] FIG. 1 is a perspective view showing the appearance of an energy storage element according to an embodiment. FIG. 2 is a perspective view showing the internal configuration of a container of an energy storage element according to an embodiment, with a container body separated from the container. FIG. 3 is a perspective view of the internal configuration of a container of an energy storage element according to an embodiment, as seen from the opposite side of FIG. 2. FIG. 4 is an exploded perspective view showing components of an energy storage element according to an embodiment, other than the container body, disassembled. FIG. 5 is a side view showing the configuration of a first bonding portion according to an embodiment. FIG. 6 is a cross-sectional view showing the configuration of a first bonding portion according to an embodiment. FIG. 7 is a side view showing the configuration of a second bonding portion according to an embodiment. FIG. 8 is a flowchart showing manufacturing steps in a method for manufacturing an energy storage element according to an embodiment. FIG. 9 is a perspective view showing a step of bundling and bonding multiple tabs provided on a first tab portion of an electrode body in a method for manufacturing an energy storage element according to an embodiment. FIG. 10 is a perspective view showing a step of arranging a first electrode body connection portion of a first current collector so that the first electrode body connection portion faces the electrode body main body portion of the electrode body in a method for manufacturing an energy storage element according to an embodiment. Fig. 11 is a perspective view showing a step of bending the first tab portion and arranging the first tab portion in a direction opposite to the electrode body main body portion with respect to the first electrode body connection portion in a manufacturing method of an energy storage element according to an embodiment. Fig. 12 is a perspective view showing a step of joining the first electrode body connection portion of the first current collector and the first tab portion of the electrode body by laser welding in a manufacturing method of an energy storage element according to an embodiment. Fig. 13 is a perspective view showing a step of joining the second electrode body connection portion of the second current collector and the second tab portion of the electrode body by laser welding in a manufacturing method of an energy storage element according to an embodiment. Fig. 14 is a plan view showing an example of an energy storage device according to an embodiment.

[0010] (1) A manufacturing method for a storage element according to one aspect of the present invention is a manufacturing method for a storage element comprising a terminal, an electrode body, and a current collector connected to the terminal and the electrode body, wherein the electrode body comprises a main body portion and a tab portion protruding from the main body portion, the current collector comprises a terminal connection portion connected to the terminal and an electrode body connection portion connected to the tab portion, the terminal connection portion and the electrode body connection portion are arranged in positions facing in different directions and are integrally formed, and the manufacturing method for the storage element includes joining the electrode body connection portion and the tab portion by laser welding.

[0011] According to a manufacturing method of an energy storage element according to one aspect of the present invention, the terminal connection portion of the current collector and the electrode assembly connection portion are disposed facing in different directions and are integrally formed, and the electrode assembly connection portion and the tab portion of the electrode assembly are joined by laser welding. In this way, even when the terminal connection portion of the current collector and the electrode assembly connection portion are integrally formed, the electrode assembly connection portion and the tab portion can be joined from the outside by laser welding, making it possible to easily join the electrode assembly connection portion and the tab portion. Therefore, it is possible to easily join the current collector and the tab portion of the electrode assembly.

[0012] (2) The manufacturing method of the energy storage element described in (1) above may further include positioning the electrode body connection portion so that it faces the main body portion, and may include joining the electrode body connection portion by laser welding after positioning the electrode body connection portion.

[0013] According to the manufacturing method of the energy storage element described in (2) above, the electrode assembly connection portion of the current collector is positioned so that it faces the main body portion of the electrode assembly, and then the electrode assembly connection portion and the tab portion of the electrode assembly are joined by laser welding. If the electrode assembly connection portion is positioned so that it faces the main body portion of the electrode assembly in order to increase the size of the electrode assembly and thereby achieve higher capacity, for example, it may be difficult to access the gap between the electrode assembly connection portion and the main body portion of the electrode assembly, which may make the joining operation between the electrode assembly connection portion and the tab portion difficult. For this reason, the electrode assembly connection portion and the tab portion are joined by laser welding. This makes it possible to easily join the electrode assembly connection portion and the tab portion even when the electrode assembly connection portion is positioned so that it faces the main body portion of the electrode assembly.

[0014] (3) In the method for manufacturing an energy storage element described in (1) or (2) above, the energy storage element may include, as the current collector having the terminal connection portion and the electrode body connection portion, a positive current collector having a positive terminal connection portion and a positive electrode body connection portion, and a negative current collector having a negative terminal connection portion and a negative electrode body connection portion, the electrode body may include, as the tab portion, a positive tab portion and a negative tab portion, and the joining by laser welding may include joining the positive electrode body connection portion and the positive tab portion by laser welding, and joining the negative electrode body connection portion and the negative tab portion by laser welding.

[0015] According to the manufacturing method of an energy storage element described in (3) above, the positive electrode assembly connection portion of the positive electrode current collector and the positive electrode tab portion of the electrode assembly are joined by laser welding, and the negative electrode assembly connection portion of the negative electrode current collector and the negative electrode tab portion of the electrode assembly are joined by laser welding. If the terminal connection portion and the electrode assembly connection portion are integrally formed on both the positive electrode current collector and the negative electrode current collector, joining the electrode assembly connection portion and the tab portion of the electrode assembly may become even more difficult. Therefore, the electrode assembly connection portion and the tab portion of both the positive electrode current collector and the negative electrode current collector are joined by laser welding. This allows the electrode assembly connection portion and the tab portion of both the positive electrode current collector and the negative electrode current collector to be joined from the outside, making it easy to join the electrode assembly connection portion and the tab portion. Therefore, it is easy to join the tab portion of the electrode assembly on both the positive electrode current collector and the negative electrode current collector.

[0016] (4) In the method for manufacturing an energy storage element described in any one of (1) to (3) above, the tab portion may include a plurality of tabs, and the method for manufacturing the energy storage element may further include bundling and joining the plurality of tabs, and after bundling and joining the plurality of tabs, may include joining them by laser welding.

[0017] According to the manufacturing method of the energy storage element described in (4) above, after bundling and joining the plurality of tabs provided in the tab portion of the electrode body, the electrode body connection portion of the current collector and the tab portion are joined by laser welding. In this way, since the plurality of tabs are bundled together when laser welding the electrode body connection portion and the tab portion, deterioration of welding quality during laser welding can be suppressed.

[0018] (5) The manufacturing method of the energy storage element described in any one of (1) to (4) above may further include bending the tab portion, and after bending the tab portion, may include joining the tab portion by laser welding.

[0019] According to the manufacturing method of the energy storage element described in (5) above, after bending the tab portion of the electrode body, the electrode body connection portion of the current collector and the tab portion are joined by laser welding. By bending the tab portion and then joining it to the electrode body connection portion in this way, the joining operation between the electrode body connection portion and the tab portion can be facilitated.

[0020] (6) The manufacturing method of the storage element described in any one of (1) to (5) above may further include arranging the tab portion in a direction opposite to the main body portion relative to the electrode body connection portion, and may include joining the tab portion by laser welding after arranging the tab portion.

[0021] According to the manufacturing method of the energy storage element described in (6) above, the tab portion is arranged on the electrode body connection portion of the current collector in the opposite direction to the main body portion of the electrode body, and then the electrode body connection portion and the tab portion are joined by laser welding. In this way, by arranging the tab portion on the outside of the electrode body connection portion and then laser welding the electrode body connection portion and the tab portion, the joining operation by laser welding can be facilitated.

[0022] (7) An energy storage element according to one aspect of the present invention comprises a terminal, an electrode body, and a current collector connected to the terminal and the electrode body, the electrode body comprising a main body portion and a tab portion protruding from the main body portion, the current collector comprising a terminal connection portion connected to the terminal and an electrode body connection portion connected to the tab portion, the terminal connection portion and the electrode body connection portion being arranged in positions facing in different directions and being integrally formed, and the electrode body connection portion and the tab portion being provided with laser welded portions formed by laser welding.

[0023] In an energy storage element according to one aspect of the present invention, the terminal connection portion of the current collector and the electrode assembly connection portion are disposed facing in different directions and are integrally formed, and laser welds are provided on the electrode assembly connection portion and the tab portion of the electrode assembly. Even when the terminal connection portion of the current collector and the electrode assembly connection portion are integrally formed, the electrode assembly connection portion and the tab portion are easily joined by laser welding from the outside because laser welds are provided on the electrode assembly connection portion and the tab portion. Therefore, this configuration allows the current collector and the tab portion of the electrode assembly to be easily joined.

[0024] Hereinafter, a method for manufacturing an energy storage element and an energy storage element according to an embodiment of the present invention (including its modified examples) will be described with reference to the drawings. The embodiments described below all show 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 examples and are not intended to limit the present invention. In each drawing, dimensions, etc. are not strictly illustrated. In each drawing, the same or similar components are assigned the same reference numerals.

[0025] In the following description and drawings, the X-axis direction is defined as the direction in which the short sides of the container of the energy storage element face each other, the direction in which the pair of terminals (positive and negative electrodes; the same applies hereinafter) of the energy storage element are aligned, the direction in which the pair of current collectors are aligned, the direction in which the electrode assembly connection portions of the current collectors face, the thickness direction of the electrode assembly connection portions, the winding axis direction of the electrode assembly, or the longitudinal direction of the electrode assembly. The Y-axis direction is defined as the thickness direction of the container (the direction in which the width is smallest; the same applies hereinafter), the direction in which the long sides of the container face each other, the alignment direction of the two electrode assemblies, or the thickness direction of one electrode assembly. The Z-axis direction is defined as the alignment direction of the container body and lid of the container, the alignment direction of the electrode assemblies and terminals, the direction in which the terminals protrude from the container, the direction in which the terminal connection portions of the current collectors face, the thickness direction of the terminal connection portions, 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 usage mode, 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.

[0026] In the following description, the positive X-axis direction refers to the direction of the arrow on the X-axis, and the negative X-axis direction refers to the direction opposite to the positive X-axis direction. 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 direction and the Z-axis direction. Expressions indicating relative directions or attitudes, such as parallel and orthogonal, also include cases where the directions or attitudes are not strictly those. When two directions are parallel (or orthogonal), it does not only mean that the two directions are completely parallel (or orthogonal), but also means that the directions are substantially parallel (or orthogonal), that is, there is a difference of about a few percent. In the following description, when the term "insulation" is used, it means "electrical insulation". An insulating material has a volume resistivity of 1×10 ６ Ωm or more, more preferably 1×10 ７ Ωm or more, more preferably 1×10 １０ It is preferable that the material be made of a material with a resistance of Ωm or more.

[0027] (Embodiment) [1. Description of the Configuration of Energy Storage Element 10] First, the configuration of the energy storage element 10 according to the present embodiment will be described in detail with reference to Figs. 1 to 4. Fig. 1 is a perspective view showing the external appearance of the energy storage element 10 according to the present embodiment. Fig. 2 is a perspective view showing the internal configuration of the container 100 of the energy storage element 10 according to the present embodiment, with the container body 110 separated from the container 100. Fig. 3 is a perspective view showing the internal configuration of the container 100 in the energy storage element 10 according to the present embodiment, as seen from the opposite side of Fig. 2. Fig. 4 is an exploded perspective view showing the components of the energy storage element 10 according to the present embodiment, other than the container body 110.

[0028] The energy storage element 10 is a secondary battery (single cell) that can charge and discharge electricity, and more specifically, a nonaqueous electrolyte secondary battery such as a lithium-ion secondary battery. The energy storage element 10 is used as a battery for driving or starting the engine of a mobile object such as an automobile, a motorcycle, or an electric railway vehicle. Examples of such automobiles include electric vehicles (EVs), hybrid electric vehicles (HEVs), and plug-in hybrid electric vehicles (PHEVs). The energy storage element 10 can also be used as a stationary battery for home or business use.

[0029] 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 be a primary battery instead of a secondary battery. The energy storage element 10 may be a battery using a solid electrolyte. In the present embodiment, the energy storage element 10 is illustrated as having a rectangular parallelepiped (square) shape that is flattened in the Y-axis direction, but the shape of the energy storage element 10 is not limited to a rectangular parallelepiped shape, and may be a polygonal prism shape other than a rectangular parallelepiped, an elongated cylinder shape, an elliptical cylinder shape, a cylindrical shape, or the like.

[0030] As shown in FIG. 1 , the energy storage element 10 includes a container 100, a pair of (positive and negative) terminals 200, and a pair of (positive and negative) upper gaskets 310. As shown in FIGS. 2 to 4 , the energy storage element 10 further includes a pair of (positive and negative) lower gaskets 320, an electrode assembly 400, and a pair of (positive and negative) current collectors 500, all of which are housed within the container 100. An electrolyte (non-aqueous electrolyte) is sealed within the container 100, but is not shown. The type of electrolyte is not particularly limited as long as it does not impair the performance of the energy storage element 10, and various types can be selected. In addition to the above components, the energy storage element 10 may also include spacers disposed on the sides or below the electrode assembly 400, an insulating film encasing the electrode assembly 400, and the like.

[0031] [1.1 Description of Container 100] The container 100 is a rectangular parallelepiped (square or box-shaped) case that includes a container body 110 with an opening facing in the positive direction of the Z axis, and a lid 120 that closes the opening of the container body 110. The container body 110 is a rectangular cylindrical member with a bottom that forms the main body of the container 100. The lid 120 is a member that forms the lid of the container 100, and is disposed in the positive direction of the Z axis of the container body 110. The lid 120 is a flat, rectangular wall that extends in the X axis direction.

[0032] The container body 110 has a pair of short side walls 111 on both sides in the X-axis direction (short sides), a pair of long side walls 112 on both sides in the Y-axis direction (long sides), and a bottom wall 113 on the surface in the negative Z-axis direction (bottom surface) (see FIG. 2 ). The short side walls 111 are flat, rectangular walls extending in the Z-axis direction. The short side walls 111 are adjacent to the long side walls 112, the bottom wall 113, and the lid 120, and have a smaller area than the long side walls 112. The long side walls 112 are flat, rectangular walls extending in the X-axis direction. The long side walls 112 are adjacent to the short side walls 111, the bottom wall 113, and the lid 120, and have a larger area than the short side walls 111. The bottom wall 113 is a flat, rectangular wall extending in the X-axis direction. The bottom wall 113 is disposed adjacent to the short side wall 111 and the long side wall 112. Depending on the shape of the container 100, the short side wall 111 may be longer in the Y-axis direction, the long side wall 112 may be longer in the Z-axis direction, and the bottom wall 113 may be longer in the Y-axis direction.

[0033] After the electrode assembly 400 and other components are housed inside the container body 110, the container body 110 and the lid 120 are joined by welding or the like, thereby sealing the interior of the container 100. The material of the container 100 (the container body 110 and the lid 120) is not particularly limited and may be a weldable (joinable) metal such as stainless steel, aluminum, aluminum alloy, iron, or plated steel sheet, or a resin. The container 100 may be formed of a laminate film or the like composed of multiple layers including a metal layer and a resin layer. The container body 110 and the lid 120 may be formed of the same material or different materials. The container 100 (lid 120) may be provided with a liquid injection section for injecting an electrolyte into the container 100 during the manufacture of the energy storage device 10, and a gas exhaust valve for releasing pressure inside the container 100 if the pressure inside the container 100 increases excessively.

[0034] [1.2 Description of Terminal 200, Upper Gasket 310, and Lower Gasket 320] The terminals 200 are electrode terminals (positive and negative terminals) electrically connected to the electrode assembly 400 via the current collector 500. The terminals 200 are metal members for conducting electricity stored in the electrode assembly 400 to the external space of the energy storage element 10 and for introducing electricity into the internal space of the energy storage element 10 to store electricity in the electrode assembly 400. The terminals 200 are formed of a conductive member such as a metal, such as aluminum, an aluminum alloy, copper, or a copper alloy. The terminals 200 are connected (joined) to the current collector 500 by crimping, welding, or the like, and are attached to the lid 120. The terminals 200 are arranged so as to protrude in the positive Z-axis direction from the outer surface (the surface facing the positive Z-axis direction) of the lid 120. In this embodiment, terminal 200 is a welding terminal that is joined to an external conductive member such as a bus bar by welding, but terminal 200 may also be a bolt terminal that has a bolt portion formed with a male thread portion that protrudes in the positive direction of the Z axis and is joined to the conductive member by a bolt connection.

[0035] In this embodiment, two terminals 200 (a positive terminal 200 and a negative terminal 200) are arranged side by side in the X-axis direction. Hereinafter, one of the two terminals 200 (the terminal 200 located in the positive direction of the X-axis) will be referred to as a first terminal 210, and the other (the terminal 200 located in the negative direction of the X-axis) will be referred to as a second terminal 220. In this embodiment, the first terminal 210 is the positive terminal 200 (positive terminal), and the second terminal 220 is the negative terminal 200 (negative terminal).

[0036] The upper gasket 310 is a plate-like, rectangular gasket that is disposed between the lid 120 of the container 100 and the terminal 200, and is responsible for insulation and sealing between the lid 120 and the terminal 200. The lower gasket 320 is a plate-like, rectangular gasket that is disposed between the lid 120 and the current collector 500, and is responsible for insulation between the lid 120 and the current collector 500. The upper gasket 310 and the lower gasket 320 can be made of any suitable known material, such as an insulating material such as resin.

[0037] [1.3 Description of the Electrode Assembly 400] The electrode assembly 400 is an electricity storage element (power generation element) formed by stacking positive and negative electrode plates and a separator. The electrode assembly 400 is a wound electrode assembly formed by winding the positive and negative electrode plates and a separator around a winding axis extending in the X-axis direction. The winding axis is an imaginary axis that serves as the central axis when winding the positive and negative electrode plates, etc. In this embodiment, it is a straight line that passes through the center of the electrode assembly 400 and is parallel to the X-axis direction. In this embodiment, the electrode assembly 400 has an elongated shape extending in the X-axis direction and has a substantially oval cylindrical shape (an oval shape when viewed in the X-axis direction). The shape of the electrode assembly 400 is not particularly limited and may be a substantially cylindrical shape or a substantially elliptical cylindrical shape, and the length of the electrode assembly 400 in the X-axis direction is also not particularly limited. The electrode assembly 400 may be elongated in the Z-axis direction.

[0038] The positive electrode plate is an electrode plate in which a positive electrode active material layer is formed on the surface of a positive electrode current collector foil, which is a long, strip-shaped current collector foil (metal foil) made of a metal such as aluminum or an aluminum alloy. The negative electrode plate is an electrode plate in which a negative electrode active material layer is formed on the surface of a negative electrode current collector foil, which is a long, strip-shaped current collector foil (metal foil) made of a metal such as copper or a copper alloy. Any known material can be used for the positive electrode current collector foil and the negative electrode current collector foil, as long as it is stable against oxidation-reduction reactions during charging and discharging. Any known material can be used for the positive electrode active material used in the positive electrode active material layer and the negative electrode active material used in the negative electrode active material layer, as long as it is capable of absorbing and releasing charge-transporting ions.

[0039] The separator is a microporous insulating sheet made of resin or the like. Any known material can be used as the separator material as long as it does not impair the performance of the energy storage element 10. Examples of the separator include woven fabric, nonwoven fabric, and porous resin film.

[0040] The positive electrode plate has multiple tabs (positive electrode tabs) protruding to one side in the X-axis direction, and by winding the positive electrode plate, a positive electrode tab portion is formed in which the multiple tabs (positive electrode tabs) are overlapped (bundled). The negative electrode plate has multiple tabs (negative electrode tabs) protruding to the other side in the X-axis direction, and by winding the negative electrode plate, a negative electrode tab portion is formed in which the multiple tabs (negative electrode tabs) are overlapped (bundled). As a result, the electrode body 400 is configured to include an electrode body main body 410, a first tab portion 420 protruding from the electrode body main body 410 in the positive direction of the X-axis, and a second tab portion 430 protruding from the electrode body main body 410 in the negative direction of the X-axis.

[0041] The electrode body main body 410 is the main body of the electrode body 400, and is an elongated cylindrical portion formed by winding the separator and portions of the positive and negative electrode plates other than the tabs. The first tab portion 420 and the second tab portion 430 are portions that extend (protrude) outward from part of the X-axis direction edge of the electrode body main body 410. In this embodiment, the first tab portion 420 is a tab portion of the positive electrode (positive electrode tab portion). The second tab portion 430 is a tab portion of the negative electrode (negative electrode tab portion).

[0042] In this embodiment, the energy storage device 10 includes two electrode bodies 400 (electrode body 401 and electrode body 402). Both electrode body 401 and electrode body 402 are wound electrode bodies formed by winding a positive electrode plate, a negative electrode plate, and a separator. Therefore, the electrode body 401 is configured to include an electrode body main body portion 411, a first tab portion 421 protruding from the electrode body main body portion 411 in the positive direction of the X-axis, and a second tab portion 431 protruding from the electrode body main body portion 411 in the negative direction of the X-axis. Similarly, the electrode body 402 is configured to include an electrode body main body portion 412, a first tab portion 422 protruding from the electrode body main body portion 412 in the positive direction of the X-axis, and a second tab portion 432 protruding from the electrode body main body portion 412 in the negative direction of the X-axis.

[0043] The first tab portion 420 (421, 422) and the second tab portion 430 (431, 432) are examples of tab portions. The first tab portion 420 (421, 422) is a positive electrode tab portion (positive electrode tab portion) having a plurality of positive electrode tabs (positive electrode tabs), and the second tab portion 430 (431, 432) is a negative electrode tab portion (negative electrode tab portion) having a plurality of negative electrode tabs (negative electrode tabs). The electrode assembly 400 (401, 402) has a positive electrode tab portion (first tab portion 420 (421, 422)) and a negative electrode tab portion (second tab portion 430 (431, 432)) as tab portions. The first tab portion 420 (421 and 422) is connected (joined) to a first electrode assembly connection portion 512 of the first current collector 510 described below. The second tab portion 430 (431 and 432) is connected (joined) to a second electrode assembly connecting portion 522 of the second current collector 520 described below.

[0044] [1.4 Description of the Current Collector 500] The current collectors 500 are conductive current collecting members (positive electrode current collector and negative electrode current collector) that are arranged on both sides of the electrode body 400 in the X-axis direction and are connected (joined) to the terminal 200 and the electrode body 400 to electrically connect the terminal 200 and the electrode body 400. The current collector 500 has a shape in which a single plate-like member is bent, and is an L-shaped (inverted L-shaped) member when viewed in the Y-axis direction. The current collector 500 has a simple configuration and is easy to manufacture. Because the current collector 500 can be formed from a single plate-like member, there is no need to provide a separate lead, etc., and the number of parts can be reduced. Furthermore, by reducing the space occupied by the current collector 500 (space saving), the capacity of the energy storage element 10 can be increased.

[0045] In this embodiment, two current collectors 500 (a positive electrode current collector 500 and a negative electrode current collector 500) are arranged side by side in the X-axis direction. Hereinafter, one of the two current collectors 500 (the current collector 500 located in the positive direction of the X-axis) will be referred to as a first current collector 510, and the other (the current collector 500 located in the negative direction of the X-axis) will be referred to as a second current collector 520. In this embodiment, the first current collector 510 is the positive electrode current collector 500 (positive electrode current collector), and the second current collector 520 is the negative electrode current collector 500 (negative electrode current collector). The first current collector 510 (positive electrode current collector) is made of aluminum, an aluminum alloy, or the like, similar to the positive electrode current collector foil of the electrode assembly 400. The second current collector 520 (negative electrode current collector) is made of copper, a copper alloy, or the like, similar to the negative electrode current collector foil of the electrode assembly 400.

[0046] 4, the first current collector 510 includes a first terminal connection portion 511 and a first electrode assembly connection portion 512. The first terminal connection portion 511 and the first electrode assembly connection portion 512 are integrally formed. In the present embodiment, the first terminal connection portion 511 and the first electrode assembly connection portion 512 are integrally formed continuously (continuously), but another portion (an intermediate portion) may be disposed between the first terminal connection portion 511 and the first electrode assembly connection portion 512, and these may be integrally formed.

[0047] The first terminal connection portion 511 is a plate-like (flat) rectangular portion parallel to the XY plane, and is connected (joined) to the terminal 200 (first terminal 210). The first terminal connection portion 511 is arranged along the lid body 120, and has a through hole 501 through which a shaft portion 201 of the first terminal 210 passes. The shaft portion 201 is a rivet portion of the first terminal 210 that extends in the negative Z-axis direction. The shaft portion 201 is inserted into the through hole 311 of the upper gasket 310, the through hole 121 of the lid body 120, the through hole 321 of the lower gasket 320, and the through hole 501 of the first terminal connection portion 511, and is crimped. As a result, the first current collector 510 is fixed to the lid body 120 together with the first terminal 210. The method of connecting (joining) the first current collector 510 and the first terminal 210 is not limited to crimping, and welding such as ultrasonic welding, laser welding, or resistance welding, or mechanical joining other than crimping such as screw joining, may also be used.

[0048] The first electrode assembly connection portion 512 is a plate-like (flat) rectangular portion parallel to the YZ plane, and is connected (joined) to the electrode assembly 400. The first electrode assembly connection portion 512 extends in the negative Z-axis direction from the end of the first terminal connection portion 511 in the positive X-axis direction along the short side wall portion 111 of the container body 110 in the positive X-axis direction. As a result, the first terminal connection portion 511 and the first electrode assembly connection portion 512 are arranged in orientations facing different directions, and the first electrode assembly connection portion 512 is arranged in an orientation facing the electrode assembly main body portion 410 (411 and 412). The first electrode assembly connection portion 512 is arranged so that its plate-like flat surface (plate surface, main surface) faces the electrode assembly main body portion 410 (411 and 412). The first electrode assembly connection portion 512 is connected (joined) to the first tab portion 420 of the electrode assembly 400. Specifically, the first electrode assembly connecting portion 512 is connected (joined) to the first tab portion 421 of the electrode assembly 401 and the first tab portion 422 of the electrode assembly 402 .

[0049] As shown in FIG. 2 , a first tab portion 420 (421 and 422) is joined to the first electrode assembly connection portion 512, thereby forming a first joint portion 600. Specifically, the first tab portion 420 is bent toward the first current collector 510, disposed on the outside of the first current collector 510, and joined to the first current collector 510. The first tab portion 421 is bent toward the first electrode assembly connection portion 512 in the positive Y-axis direction, disposed in the positive X-axis direction of the first electrode assembly connection portion 512, and joined to the first electrode assembly connection portion 512, thereby forming the first joint portion 600. The first tab portion 422 is bent toward the first electrode assembly connection portion 512 in the negative Y-axis direction, disposed in the positive X-axis direction of the first electrode assembly connection portion 512, and joined to the first electrode assembly connection portion 512, thereby forming the first joint portion 600. In this way, the first tab portion 420 (421 and 422) is joined to the outside of the first current collector 510 (first electrode body connection portion 512) by wrapping around both sides of the first current collector 510 (first electrode body connection portion 512) in the Y-axis direction.

[0050] Similar to the first current collector 510, the second current collector 520 includes a second terminal connection portion 521 and a second electrode assembly connection portion 522. The second terminal connection portion 521 and the second electrode assembly connection portion 522 are integrally formed. In the present embodiment, the second terminal connection portion 521 and the second electrode assembly connection portion 522 are integrally formed continuously (continuously), but another portion (an intermediate portion) may be disposed between the second terminal connection portion 521 and the second electrode assembly connection portion 522, and these may be integrally formed.

[0051] The second terminal connection portion 521 is a plate-like (flat) rectangular portion parallel to the XY plane, and is connected (joined) to the terminal 200 (second terminal 220). The second terminal connection portion 521 is arranged along the lid body 120, and has a through-hole 501 through which the shaft portion 201 of the second terminal 220 passes. The configuration in which the second terminal connection portion 521 is joined to the second terminal 220 is similar to the configuration in which the first terminal connection portion 511 is joined to the first terminal 210, and therefore a detailed description thereof will be omitted.

[0052] The second electrode assembly connection portion 522 is a plate-like (flat) rectangular portion parallel to the YZ plane, and is connected (joined) to the electrode assembly 400. The second electrode assembly connection portion 522 extends in the negative Z-axis direction from the end of the second terminal connection portion 521 in the negative X-axis direction along the short side wall portion 111 of the container body 110 in the negative X-axis direction. As a result, the second terminal connection portion 521 and the second electrode assembly connection portion 522 are arranged in orientations facing different directions, and the second electrode assembly connection portion 522 is arranged in an orientation facing the electrode assembly main portions 411 and 412. The second electrode assembly connection portion 522 is connected (joined) to the second tab portion 430 of the electrode assembly 400. Specifically, the second electrode assembly connection portion 522 is connected (joined) to the second tab portion 431 of the electrode assembly 401 and the second tab portion 432 of the electrode assembly 402.

[0053] As shown in FIG. 3 , a second tab portion 430 (431 and 432) is joined to the second electrode assembly connection portion 522, thereby forming a second joint portion 700. Specifically, the second tab portion 430 is bent toward the second current collector 520, disposed on the outside of the second current collector 520, and joined to the second current collector 520. The second tab portion 431 is bent toward the second electrode assembly connection portion 522 in the positive Y-axis direction, disposed in the negative X-axis direction of the second electrode assembly connection portion 522, and joined to the second electrode assembly connection portion 522, thereby forming the second joint portion 700. The second tab portion 432 is bent toward the negative Y-axis direction, disposed in the negative X-axis direction of the second electrode assembly connection portion 522, and joined to the second electrode assembly connection portion 522, thereby forming the second joint portion 700. In this way, the second tab portion 430 (431 and 432) is joined to the outside of the second current collector 520 (second electrode body connection portion 522) while wrapping around both sides of the second current collector 520 (second electrode body connection portion 522) in the Y-axis direction.

[0054] The first terminal connection portion 511 and the second terminal connection portion 521 are examples of terminal connection portions, and the first electrode assembly connection portion 512 and the second electrode assembly connection portion 522 are examples of electrode assembly connection portions. In the present embodiment, the first current collector 510 is a positive current collector, so the first terminal connection portion 511 can be referred to as a positive terminal connection portion, and the first electrode assembly connection portion 512 can be referred to as a positive electrode assembly connection portion. The second current collector 520 is a negative current collector, so the second terminal connection portion 521 can be referred to as a negative terminal connection portion, and the second electrode assembly connection portion 522 can be referred to as a negative electrode assembly connection portion. The energy storage element 10 includes, as current collectors having terminal connection portions and electrode body connection portions, a positive current collector having a positive terminal connection portion and a positive electrode body connection portion (a first current collector 510 having a first terminal connection portion 511 and a first electrode body connection portion 512), and a negative current collector having a negative terminal connection portion and a negative electrode body connection portion (a second current collector 520 having a second terminal connection portion 521 and a second electrode body connection portion 522).

[0055] [1.5 Description of First Joint Section 600 and Second Joint Section 700] Next, the configurations of the first joint section 600 and the second joint section 700 according to this embodiment will be described in detail with reference to FIGS. 5 to 7. FIG. 5 is a side view showing the configuration of the first joint section 600 according to this embodiment. FIG. 5 is a view of the configuration shown in FIG. 2 (excluding the container body 110) as viewed from the positive direction of the X-axis, with the upper gasket 310 and the lower gasket 320 omitted. FIG. 6 is a cross-sectional view showing the configuration of the first joint section 600 according to this embodiment. FIG. 6 shows a cross-section of the configuration shown in FIG. 5 taken along a plane parallel to the XY plane including line VI-VI. FIG. 7 is a side view showing the configuration of the second joint section 700 according to this embodiment. FIG. 7 is a view of the configuration shown in FIG. 3 as viewed from the negative direction of the X-axis, with the upper gasket 310 and the lower gasket 320 omitted.

[0056] 2 and 5, the first joint portion 600 is a long joint portion extending in the Z-axis direction formed by joining the first electrode body connection portion 512 and the first tab portion 420. Two first joint portions 600 are formed for the first tab portions 421 and 422. As shown in FIGS. 5 and 6, the first joint portion 600 includes a tab joint portion 610 and a laser weld portion 620.

[0057] The tab joint 610 is a joint formed by bundling multiple tabs (positive electrode tabs) included in the first tab portion 420 (421, 422) of the electrode assembly 400 (401, 402) and joining the tabs together. The tab joint 610 is formed to extend continuously in the Z-axis direction from one end to the other end of the first tab portion 420 in the Z-axis direction. As shown in FIG. 6 , the tab joint 610 is formed from one end to the other end of the first tab portion 420 in the X-axis direction. The tab joint 610 is formed continuously from the tab at the end in the positive X-axis direction of the first tab portion 420 to the tab at the end in the negative X-axis direction of the first tab portion 420. The tab joint 610 is not formed on the first current collector 510 (first electrode assembly connection portion 512). In the present embodiment, the tab joint 610 is a joint mark (ultrasonic joint mark) formed by ultrasonic bonding. The joining method for forming the tab joint 610 may be a method other than ultrasonic joining, such as resistance welding, laser welding, crimping joining, or screw joining, but ultrasonic joining is preferred because it allows for a larger area for bundling multiple tabs and is easy to produce.

[0058] The laser weld 620 is a weld formed by laser welding and provided on the first electrode assembly connection portion 512 of the first current collector 510 and the first tab portion 420 (421, 422). The laser weld 620 is a weld (laser weld mark) formed by joining the first electrode assembly connection portion 512 and the first tab portion 420 by laser welding. The laser weld 620 is formed so as to extend continuously in the Z-axis direction from one end to the other end of the first tab portion 420 in the Z-axis direction. Specifically, the laser weld 620 is formed so as to be continuously formed from one end to the other end of the tab joint 610 in the Z-axis direction. The laser weld 620 is formed so as to be located within the tab joint 610 when viewed from the X-axis direction. As shown in Figure 6, the laser weld 620 is formed continuously from the end of the first tab portion 420 in the positive X-axis direction, past the end of the first tab portion 420 in the negative X-axis direction, and up to the first electrode body connection portion 512.

[0059] 3 and 7 , the second joint portion 700 is a long joint portion extending in the Z-axis direction formed by joining the second electrode body connection portion 522 and the second tab portion 430. Two second joint portions 700 are formed for the second tab portions 431 and 432. Like the first joint portion 600, the second joint portion 700 includes a tab joint portion 710 and a laser weld portion 720.

[0060] The tab joint 710 is a joint formed by bundling multiple tabs (negative electrode tabs) provided on the second tab portion 430 (431, 432) of the electrode assembly 400 (401, 402) and joining the tabs together. The tab joint 710 has a similar configuration to the tab joint 610, and therefore a detailed description thereof will be omitted. The laser weld 720 is a weld formed by laser welding provided on the second electrode assembly connection portion 522 of the second current collector 520 and the second tab portion 430 (431, 432). The laser weld 720 is a weld (laser weld mark) formed by joining the second electrode assembly connection portion 522 and the second tab portion 430 by laser welding. The laser weld 720 has a similar configuration to the laser weld 620, and therefore a detailed description thereof will be omitted.

[0061] [2 Description of Manufacturing Method of Energy Storage Element 10] Next, a manufacturing method of the energy storage element 10 according to the present embodiment will be described in detail with reference to FIGS. 8 to 13. FIG. 8 is a flowchart showing manufacturing steps in the manufacturing method of the energy storage element 10 according to the present embodiment. FIG. 9 is a perspective view showing a step of bundling and joining a plurality of tabs provided on the first tab portion 420 of the electrode assembly 400 in the manufacturing method of the energy storage element 10 according to the present embodiment. FIG. 10 is a perspective view showing a step of arranging the first electrode assembly connecting portion 512 of the first current collector 510 so that it faces the electrode assembly main body portion 410 of the electrode assembly 400 in the manufacturing method of the energy storage element 10 according to the present embodiment. FIG. 11 is a perspective view showing a step of bending the first tab portion 420 and arranging the first tab portion 420 in the opposite direction to the electrode assembly main body portion 410 relative to the first electrode assembly connecting portion 512 in the manufacturing method of the energy storage element 10 according to the present embodiment. Fig. 12 is a perspective view showing a step of joining by laser welding the first electrode assembly connecting portion 512 of the first current collector 510 and the first tab portion 420 of the electrode assembly 400 in the manufacturing method of the energy storage element 10 according to the present embodiment. Fig. 13 is a perspective view showing a step of joining by laser welding the second electrode assembly connecting portion 522 of the second current collector 520 and the second tab portion 430 of the electrode assembly 400 in the manufacturing method of the energy storage element 10 according to the present embodiment.

[0062] 8 , first, a plurality of tabs included in the first tab portion 420 of the electrode body 400 are bundled and joined (step S101: “bundling and joining a plurality of tabs”). The manufacturing method for the energy storage element 10 includes bundling and joining a plurality of tabs included in the first tab portion 420.

[0063] Specifically, as shown in FIG. 9 , multiple tabs included in the first tab portion 420 (421, 422) of the electrode assembly 400 (401, 402) are bundled and joined to form a tab joint 610. Two tab joints 610 are formed for the first tab portion 421 of the electrode assembly 401 and the first tab portion 422 of the electrode assembly 402. The tab joint 610 for the first tab portion 421 and the tab joint 610 for the first tab portion 422 may be formed in a state in which the electrode assembly 401 and the electrode assembly 402 are overlapped, as shown in FIG. 9 , or may be formed separately and then the electrode assembly 401 and the electrode assembly 402 are overlapped. By forming the tab joint 610, the multiple tabs included in the first tab portion 420 are bundled and come into contact at the position of the tab joint 610. The specific configuration of the tab joint 610 and the joining method for forming the tab joint 610 are as described above.

[0064] 8 , next, the first electrode assembly connecting portion 512 of the first current collector 510 is positioned so that it faces the electrode assembly main body portion 410 of the electrode assembly 400 (step S102: “positioning the electrode assembly connecting portion”). The manufacturing method for the energy storage element 10 further includes positioning the first electrode assembly connecting portion 512 so that it faces the electrode assembly main body portion 410.

[0065] 10 , the first current collector 510 fixed to the lid 120 together with the first terminal 210 is placed in the positive direction of the X axis of the electrode assembly 400 (401, 402). At this time, the first electrode assembly connection portion 512 of the first current collector 510 is placed between the first tab portion 421 and the first tab portion 422. As a result, the first electrode assembly connection portion 512 is placed so that the plate-shaped flat surface (plate surface, main surface) of the first electrode assembly connection portion 512 faces the electrode assembly main body portion 410 (411, 412) of the electrode assembly 400.

[0066] Returning to FIG. 8 , next, the first tab portion 420 of the electrode assembly 400 is bent (step S103: "bending the tab portion"). The manufacturing method for the energy storage element 10 further includes bending the first tab portion 420. The first tab portion 420 is arranged in the opposite direction to the electrode assembly main body portion 410 of the electrode assembly 400 relative to the first electrode assembly connecting portion 512 of the first current collector 510 (step S104: "arranging the tab portion"). The manufacturing method for the energy storage element 10 further includes arranging the first tab portion 420 in the opposite direction to the electrode assembly main body portion 410 relative to the first electrode assembly connecting portion 512.

[0067] 11 , the first tab portion 421 of the electrode assembly 401 is bent in the positive direction of the Y-axis toward the first electrode assembly connection portion 512. The first tab portion 421 is arranged in the positive direction of the X-axis of the first electrode assembly connection portion 512 (the opposite direction from the electrode assembly main body portion 410 with respect to the first electrode assembly connection portion 512). As a result, the first tab portion 421 is overlapped with the first electrode assembly connection portion 512 in the X-axis direction, and the tab joint portion 610 formed on the first tab portion 421 is arranged in the positive direction of the X-axis of the first electrode assembly connection portion 512. The first tab portion 422 of the electrode assembly 402 is bent in the negative direction of the Y-axis toward the first electrode assembly connection portion 512. The first tab portion 422 is arranged in the positive direction of the X-axis of the first electrode assembly connection portion 512 (the opposite direction from the electrode assembly main body portion 410 with respect to the first electrode assembly connection portion 512). As a result, the first tab portion 422 is overlapped with the first electrode body connection portion 512 in the X-axis direction, and the tab joint portion 610 formed on the first tab portion 422 is positioned in the positive X-axis direction of the first electrode body connection portion 512.

[0068] 8 , next, the first electrode assembly connection portion 512 of the first current collector 510 and the first tab portion 420 of the electrode assembly 400 are joined by laser welding (step S105: "joining by laser welding"). The manufacturing method for the energy storage element 10 further includes joining the first electrode assembly connection portion 512 and the first tab portion 420 by laser welding.

[0069] Specifically, as shown in FIG. 11 , laser light L is irradiated onto the position where the tab joint 610 of the first tab portion 420 (421, 422) is formed, to join the first electrode assembly connection portion 512 and the first tab portion 420 (421, 422) by laser welding. As a result, as shown in FIG. 12 , a laser welded portion 620 is formed at the position of the tab joint 610, where the first electrode assembly connection portion 512 and the first tab portion 420 (421, 422) are laser welded. The specific configuration of the laser welded portion 620 is as described above. As a result, a first joint portion 600 including the tab joint 610 and the laser welded portion 620 is formed in the first electrode assembly connection portion 512 of the first current collector 510 and the first tab portion 420 (421, 422) of the electrode assembly 400.

[0070] The second electrode assembly connecting portion 522 of the second current collector 520 and the second tab portion 430 (431, 432) of the electrode assembly 400 are also joined using a method similar to that of steps S101 to S105 described above. Details are the same as those of steps S101 to S105 described above, and therefore will be omitted. As a result, as shown in FIG. 13 , a second joint portion 700 including a tab joint portion 710 and a laser welded portion 720 is formed in the second electrode assembly connecting portion 522 of the second current collector 520 and the second tab portion 430 (431, 432) of the electrode assembly 400. The manufacturing method of the energy storage element 10 includes joining by laser welding (step S105), which includes joining the positive electrode assembly connection portion (first electrode assembly connection portion 512) and the positive electrode tab portion (first tab portion 420) by laser welding, and joining the negative electrode assembly connection portion (second electrode assembly connection portion 522) and the negative electrode tab portion (second tab portion 430) by laser welding.

[0071] Thus, the manufacturing method of the energy storage element 10 includes bundling and joining a plurality of tabs (step S101), followed by joining by laser welding (step S105). The manufacturing method of the energy storage element 10 includes arranging the electrode body connection portion (step S102), followed by joining by laser welding (step S105). The manufacturing method of the energy storage element 10 includes bending the tab portion (step S103), followed by joining by laser welding (step S105). The manufacturing method of the energy storage element 10 includes arranging the tab portion (step S104), followed by joining by laser welding (step S105).

[0072] [3 Description of Effects] As described above, according to the manufacturing method for the energy storage element 10 according to the embodiment of the present invention, the first electrode assembly connection portion 512 of the first current collector 510 and the first tab portion 420 (421 and 422) of the electrode assembly 400 are joined by laser welding. The first terminal connection portion 511 and the first electrode assembly connection portion 512 of the first current collector 510 are disposed facing in different directions and are integrally formed. In this way, even when the first terminal connection portion 511 and the first electrode assembly connection portion 512 of the first current collector 510 are integrally formed, the first electrode assembly connection portion 512 and the first tab portion 420 can be joined from the outside by joining them by laser welding. This makes it possible to easily join the first electrode assembly connection portion 512 and the first tab portion 420. Therefore, it is possible to easily join the first current collector 510 and the first tab portion 420 of the electrode assembly 400.

[0073] According to the manufacturing method of the energy storage element 10, the first electrode assembly connection portion 512 of the first current collector 510 is positioned so that it faces the electrode assembly main body portion 410 (411 and 412) of the electrode assembly 400, and then the first electrode assembly connection portion 512 and the first tab portion 420 (421 and 422) of the electrode assembly 400 are joined by laser welding. If the first electrode assembly connection portion 512 is positioned so that it faces the electrode assembly main body portion 410 in order to increase the size of the electrode assembly 400 and thereby achieve higher capacity, for example, it becomes difficult to access the space between the first electrode assembly connection portion 512 and the electrode assembly main body portion 410. As a result, the joining operation between the first electrode assembly connection portion 512 and the first tab portion 420 may become difficult. For this reason, the first electrode assembly connection portion 512 and the first tab portion 420 are joined by laser welding. This makes it easy to join the first electrode body connecting portion 512 and the first tab portion 420 even when the first electrode body connecting portion 512 is positioned facing the electrode body main body portion 410 of the electrode body 400.

[0074] According to the manufacturing method of the energy storage element 10, the positive electrode assembly connection portion (first electrode assembly connection portion 512) of the positive electrode current collector (first current collector 510) and the positive electrode tab portion (first tab portion 420) of the electrode assembly 400 are joined by laser welding. In addition, the negative electrode assembly connection portion (second electrode assembly connection portion 522) of the negative electrode current collector (second current collector 520) and the negative electrode tab portion (second tab portion 430) of the electrode assembly 400 are joined by laser welding. If the terminal connection portions (first terminal connection portion 511, second terminal connection portion 521) and the electrode assembly connection portions (first electrode assembly connection portion 512, second electrode assembly connection portion 522) are integrally formed on both the positive electrode current collector and the negative electrode current collector, it may become even more difficult to join the electrode assembly connection portions and the tab portions (first tab portion 420, second tab portion 430). For this reason, the electrode assembly connection portion and the tab portion of both the positive electrode current collector and the negative electrode current collector are joined by laser welding. This allows the electrode assembly connection portion and the tab portion of both the positive electrode current collector and the negative electrode current collector to be joined from the outside, making it easy to join the electrode assembly connection portion and the tab portion. Therefore, it is easy to join the tab portion of the electrode assembly 400 to both the positive electrode current collector and the negative electrode current collector.

[0075] According to the manufacturing method of the energy storage element 10, after bundling and joining the multiple tabs provided on the first tab portion 420 (421 and 422) of the electrode body 400, the first electrode body connection portion 512 of the first current collector 510 and the first tab portion 420 are joined by laser welding. In this way, because the multiple tabs are bundled together when the first electrode body connection portion 512 and the first tab portion 420 are laser welded together, a decrease in welding quality during laser welding can be suppressed.

[0076] According to the manufacturing method of the energy storage element 10, after bending the first tab portion 420 (421 and 422) of the electrode body 400, the first electrode body connection portion 512 of the first current collector 510 and the first tab portion 420 are joined by laser welding. By bending the first tab portion 420 and then joining it to the first electrode body connection portion 512 in this way, the joining operation between the first electrode body connection portion 512 and the first tab portion 420 can be facilitated.

[0077] According to the manufacturing method of the energy storage element 10, the first tab portion 420 (421 and 422) is positioned in the opposite direction to the electrode body main portion 410 (411 and 412) relative to the first electrode body connection portion 512, and then the first electrode body connection portion 512 and the first tab portion 420 are joined by laser welding. In this way, by positioning the first tab portion 420 on the outside of the first electrode body connection portion 512 and then laser welding the first electrode body connection portion 512 and the first tab portion 420, it is possible to laser weld the first tab portion 420 while pressing it toward the first electrode body connection portion 512. This makes it easier to perform the joining operation by laser welding.

[0078] In the energy storage element 10 according to the embodiment of the present invention, the first terminal connection portion 511 and the first electrode assembly connection portion 512 of the first current collector 510 are disposed facing in different directions and are integrally formed. A laser weld 620 is provided on the first electrode assembly connection portion 512 and the first tab portion 420 (421 and 422) of the electrode assembly 400. Even when the first terminal connection portion 511 and the first electrode assembly connection portion 512 of the first current collector 510 are integrally formed, the laser weld 620 is provided on the first electrode assembly connection portion 512 and the first tab portion 420, so that the first electrode assembly connection portion 512 and the first tab portion 420 can be easily joined by laser welding from the outside. Therefore, this configuration allows the first current collector 510 and the first tab portion 420 of the electrode assembly 400 to be easily joined.

[0079] The effects described above for the first current collector 510 can also be achieved for the second current collector 520 in the same manner.

[0080] The energy storage element 10 in the present embodiment may be used in an energy storage device. In this case, the technology of the present invention may be applied to at least one energy storage element 10 included in the energy storage device. FIG. 14 is a plan view showing an example of an energy storage device 12 according to the present embodiment. As shown in FIG. 14 , a plurality of energy storage units 11 are arranged inside the energy storage device 12. The energy storage unit 11 is composed of a plurality of electrically connected energy storage elements 10. The energy storage device 12 may include a bus bar (not shown) that electrically connects the plurality of energy storage elements 10, a bus bar (not shown) that electrically connects the plurality of energy storage units 11, and the like. The energy storage unit 11 or the energy storage device 12 may include a status monitoring device (not shown) that monitors the status of one or more energy storage elements 10. The energy storage device 12 may include only one energy storage unit 11. The energy storage unit 11 may also be referred to as an energy storage device.

[0081] [4 Description of Modifications] The manufacturing method of the energy storage device 10 according to the embodiment of the present invention and the energy storage device 10 have been described above, but the present invention is not limited to the above embodiment. The embodiment disclosed herein is an example in all respects, and the scope of the present invention includes all modifications within the meaning and scope of the claims.

[0082] In the above embodiment, the manufacturing method for the energy storage element 10 is performed in the order of steps S101 to S105, but any of the steps may be performed in a different order. The manufacturing method for the energy storage element 10 may include arranging an electrode assembly connection portion (step S102), bending the tab portion (step S103), or arranging the tab portion (step S104) before bundling and joining a plurality of tabs (step S101). The manufacturing method for the energy storage element 10 may include bending the tab portion (step S103) before arranging the electrode assembly connection portion (step S102). The manufacturing method for the energy storage element 10 may include arranging the tab portion (step S104) or joining by laser welding (step S105) before bending the tab portion (step S103).

[0083] In the above embodiment, the current collector 500 has a shape formed by bending a single plate-like member, but this is not limited thereto. In the first current collector 510, the first terminal connection portion 511 and the first electrode assembly connection portion 512 are not particularly limited in shape as long as they are disposed facing in different directions and are integrally formed. The same applies to the second current collector 520.

[0084] In the above embodiment, the first electrode body connection portion 512 of the first current collector 510 is arranged in an orientation facing the X-axis direction, but it may also be arranged in an orientation facing a direction tilted from the X-axis direction, or in an orientation facing the Y-axis direction. After arranging the first electrode body connection portion 512 so that it faces in a direction different from the electrode body main body portion 410, the first electrode body connection portion 512 and the first tab portion 420 may be joined by laser welding. The same applies to the second current collector 520.

[0085] In the above embodiment, both the first current collector 510 and the second current collector 520 have the above configuration and the above manufacturing method is applied, but this is not limited to this. Either the first current collector 510 or the second current collector 520 may not have the above configuration, and the above manufacturing method may not be applied. Either the first tab portions 421 and 422 may not have the above configuration, and the above manufacturing method may not be applied. The same applies to the second tab portions 431 and 432.

[0086] In the above embodiment, the position and shape of the first joint 600 (tab joint 610 and laser weld 620) are not particularly limited. The first joint 600 (tab joint 610 and laser weld 620) may be formed intermittently rather than continuously in the Z-axis direction, and may not be long in the Z-axis direction. The tab joint 610 is not limited to joining all of the tabs of the first tab portion 420, and some of the tabs may not be joined. The laser weld 620 may not be formed to be located within the tab joint 610 when viewed in the X-axis direction, but may be formed partially or entirely outside the tab joint 610. The same applies to the second joint 700 (tab joint 710 and laser weld 720).

[0087] In the above embodiment, the multiple tabs included in the first tab portion 420 of the electrode assembly 400 are bundled and joined, and then the first electrode assembly connection portion 512 of the first current collector 510 and the first tab portion 420 are joined by laser welding, but this is not limited to this. The first electrode assembly connection portion 512 and the first tab portion 420 may be joined by laser welding without joining the multiple tabs included in the first tab portion 420. The tab joint portion 610 does not need to be formed in the first tab portion 420, and the first joint portion 600 may not have the tab joint portion 610. The same applies to the second current collector 520.

[0088] In the above embodiment, after bending the first tab portion 420 of the electrode assembly 400, the first electrode assembly connection portion 512 of the first current collector 510 and the first tab portion 420 are joined by laser welding, but this is not limited to this. The first electrode assembly connection portion 512 and the first tab portion 420 may also be joined by laser welding without bending the first tab portion 420. The same applies to the second current collector 520.

[0089] In the above embodiment, the first tab portion 420 is arranged on the first electrode assembly connecting portion 512 of the first current collector 510 in the direction opposite to the electrode assembly main body portion 410, and then the first electrode assembly connecting portion 512 and the first tab portion 420 are joined by laser welding, but this is not limited to this. The first tab portion 420 may be arranged on the first electrode assembly connecting portion 512 in the direction of the electrode assembly main body portion 410, and then the first electrode assembly connecting portion 512 and the first tab portion 420 may be joined by laser welding. The first tab portion 420 may be arranged inside the first electrode assembly connecting portion 512, and then the first electrode assembly connecting portion 512 and the first tab portion 420 may be laser welded. The same applies to the second current collector 520.

[0090] In the above embodiment, the electrode assembly 400 (401, 402) is a wound electrode assembly, but is not limited to this. The electrode assembly 400 may be a laminated (stacked) electrode assembly formed by stacking a plurality of flat electrode plates, a bellows-type electrode assembly in which electrode plates are folded in a bellows shape, or an electrode assembly of other shapes.

[0091] In the above embodiment, the storage element 10 is provided with two electrode bodies 400 (401 and 402), but the number of electrode bodies 400 is not particularly limited and may be one, or three or more.

[0092] Any combination of the components included in the above-described embodiments and their modifications is also included within the scope of the present invention.

[0093] The present invention can be applied to a method for manufacturing an electric storage device such as a lithium ion secondary battery.

[0094] REFERENCE SIGNS LIST 10 Energy storage element 11 Energy storage unit 12 Energy storage device 100 Container 110 Container body 120 Lid body 200 Terminal 210 First terminal 220 Second terminal 310 Upper gasket 320 Lower gasket 400, 401, 402 Electrode body 410, 411, 412 Electrode body body portion 420, 421, 422 First tab portion 430, 431, 432 Second tab portion 500 Current collector 510 First current collector 511 First terminal connection portion 512 First electrode body connection portion 520 Second current collector 521 Second terminal connection portion 522 Second electrode body connection portion 600 First joint portion 610, 710 Tab joint portion 620, 720 Laser welded portion 700 Second joint portion

Claims

1. A method for manufacturing an energy storage element comprising a terminal, an electrode body, and a current collector connected to the terminal and the electrode body, wherein the electrode body comprises a main body portion and a tab portion protruding from the main body portion, the current collector comprises a terminal connection portion connected to the terminal, and an electrode body connection portion connected to the tab portion, the terminal connection portion and the electrode body connection portion are arranged in orientations facing in different directions and are integrally formed, and the method for manufacturing an energy storage element includes joining the electrode body connection portion and the tab portion by laser welding.

2. The method for manufacturing an energy storage element according to claim 1, further comprising: positioning the electrode body connection part so that it faces the main body part; and joining the electrode body connection part by laser welding after positioning the electrode body connection part.

3. The method for manufacturing an energy storage element according to claim 1 or 2, wherein the energy storage element comprises, as the current collector having the terminal connection portion and the electrode body connection portion, a positive current collector having a positive terminal connection portion and a positive electrode body connection portion, and a negative current collector having a negative terminal connection portion and a negative electrode body connection portion, and the electrode body comprises, as the tab portions, a positive tab portion and a negative tab portion, and the joining by laser welding includes joining the positive electrode body connection portion and the positive tab portion by laser welding, and joining the negative electrode body connection portion and the negative tab portion by laser welding.

4. The method for manufacturing an energy storage element according to claim 1 or 2, wherein the tab portion comprises a plurality of tabs, and the method for manufacturing the energy storage element further comprises bundling and joining the plurality of tabs, and after bundling and joining the plurality of tabs, joining them by laser welding.

5. The method for manufacturing an energy storage element according to claim 1 or 2, further comprising bending the tab portion, and joining the tab portion by laser welding after bending the tab portion.

6. The method for manufacturing an energy storage element according to claim 1 or 2, further comprising: arranging the tab portion in a direction opposite to the main body portion relative to the electrode body connection portion; and joining the tab portion by laser welding after arranging the tab portion.

7. An energy storage element comprising: a terminal, an electrode body, and a current collector connected to the terminal and the electrode body, wherein the electrode body comprises a main body portion and a tab portion protruding from the main body portion, wherein the current collector comprises a terminal connection portion connected to the terminal and an electrode body connection portion connected to the tab portion, wherein the terminal connection portion and the electrode body connection portion are disposed in orientations facing in different directions and are integrally formed, and wherein the electrode body connection portion and the tab portion are provided with laser welded portions formed by laser welding.

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