Method for producing power storage element, and power storage element

Abstract

Provided is a method for producing a power storage element comprising: an electrode body comprising a first electrode plate and a second electrode plate; a first current collector joined to the first electrode plate; and a second current collector joined to the second electrode plate. The method involves: sandwiching the first electrode plate and the first current collector from both sides to join the same and form a first joined portion; and joining the second electrode plate and the second current collector from one side to form a second joined portion.

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 that includes a laminated electrode body in which multiple positive electrode sheets and multiple negative electrode sheets are stacked, and in which the positive electrode sheet and the positive electrode current collector terminal are laser welded, and the negative electrode sheet and the negative electrode current collector terminal are laser welded.

[0003] Japanese Patent Application Laid-Open No. 2018-190547

[0004] In the conventional secondary battery, a laser is applied to the positive electrode sheet and the positive electrode current collector terminal from the outside to join the positive electrode sheet and the positive electrode current collector terminal by laser welding, and a laser is applied to the negative electrode sheet and the negative electrode current collector terminal from the outside to join the negative electrode sheet and the negative electrode current collector terminal by laser welding. However, during the joining operation, depending on the condition of the joining location, joining by laser welding may not be suitable. For this reason, it is desirable to be able to improve the flexibility of the joining operation.

[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 manufacturing method for an energy storage element and an energy storage element that can improve the degree of freedom in the joining work between the electrode body and the current collector.

[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 an electrode body including a first electrode plate and a second electrode plate, a first current collector joined to the first electrode plate, and a second current collector joined to the second electrode plate, and includes sandwiching and joining the first electrode plate and the first current collector from both sides to form a first joint, and joining the second electrode plate and the second current collector from one side to form a second joint.

[0007] An energy storage element according to one embodiment of the present invention comprises an electrode body having a first electrode plate and a second electrode plate, a first current collector joined to the first electrode plate, and a second current collector joined to the second electrode plate, wherein a first joint is formed between the first electrode plate and the first current collector and joined by resistance welding or ultrasonic welding, and a second joint is formed between the second electrode plate and the second current collector and joined by laser welding.

[0008] According to the method for manufacturing an electric storage element of the present invention, the degree of freedom in joining the electrode body and the current collector can be improved.

[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, viewed 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 flowchart showing manufacturing steps in a method for manufacturing an energy storage element according to an embodiment. FIG. 6 is a perspective view showing a step of attaching a current collector to a terminal in a method for manufacturing an energy storage element according to an embodiment. FIG. 7 is a perspective view showing a step of forming a first bonding portion in a method for manufacturing an energy storage element according to an embodiment. FIG. 8 is a cross-sectional view showing a step of forming a first bonding portion in a method for manufacturing an energy storage element according to an embodiment. FIG. 9 is a perspective view showing a step of bending a first electrode plate and a step of bending a second electrode plate in a method for manufacturing an energy storage element according to an embodiment. FIG. 10 is a perspective view showing a step of forming a second bonding portion in a method for manufacturing an energy storage element according to an embodiment. FIG. 11 is a plan view showing an example of an energy storage device according to a modified embodiment.

[0010] (1) A manufacturing method of a storage element according to one aspect of the present invention is a manufacturing method of a storage element including an electrode body having a first electrode plate and a second electrode plate, a first current collector joined to the first electrode plate, and a second current collector joined to the second electrode plate, the method including sandwiching and joining the first electrode plate and the first current collector from both sides to form a first joint, and joining the second electrode plate and the second current collector from one side to form a second joint.

[0011] A manufacturing method for an energy storage element according to one embodiment of the present invention includes sandwiching and joining a first electrode plate and a first current collector from both sides to form a first joint portion, and joining a second electrode plate and a second current collector from one side to form a second joint portion. In this way, the first joint portion and the second joint portion are formed by different joining methods, such that the first electrode plate and the first current collector are sandwiched and joined from both sides to form the first joint portion, and the second electrode plate and the second current collector are joined from one side to form the second joint portion. This allows the electrode assembly and the current collector to be joined by selecting a joining method appropriate for the condition of the joining location, thereby improving the flexibility of the joining operation between the electrode assembly and the current collector.

[0012] (2) In the manufacturing method of the energy storage element described in (1) above, in forming the first junction, the first junction may be formed at one end of the electrode body in a predetermined direction, and in forming the second junction, after forming the first junction, the second junction may be formed at the other end of the electrode body in the predetermined direction.

[0013] According to the manufacturing method of an energy storage element described in (2) above, after forming a first joint portion at one end of the electrode assembly, a second joint portion is formed at the other end of the electrode assembly. Here, when forming the first joint portion, the first electrode plate and the first current collector are sandwiched and joined from both sides, so it is necessary to ensure a gap on both sides of the first electrode plate and the first current collector during the joining operation. When forming the second joint portion, the second electrode plate and the second current collector are joined from one side, so it is sufficient to ensure a gap on one side of the second electrode plate and the second current collector during the joining operation. In a configuration in which joint portions are formed at both ends of the electrode assembly, performing the joining operation first makes it easier to ensure a gap. Therefore, the first joint portion is formed before the second joint portion is formed. In other words, the first joint portion is formed before the second joint portion is formed. This allows the joining operation to be performed while ensuring a gap on both sides of the first electrode plate and the first current collector during the formation of the first joint portion. This further improves the flexibility of the joining operation between the electrode assembly and the current collector.

[0014] (3) In the manufacturing method of the storage element described in (2) above, the method may further include bending the first electrode plate after the formation of the first joint portion, and the formation of the second joint portion may be performed after the bending of the first electrode plate.

[0015] According to the manufacturing method of the energy storage element described in (3) above, the first electrode plate is bent after the first joint portion is formed, and the second joint portion is formed after the first electrode plate is bent. By bending the first electrode plate after the first joint portion is formed in this manner, the second electrode plate can be brought closer to the second current collector when the second joint portion is formed. This facilitates the joining of the second electrode plate and the second current collector, and therefore facilitates the formation of the second joint portion. This further improves the flexibility of the joining operation between the electrode assembly and the current collector.

[0016] (4) In the manufacturing method of the storage element described in (3) above, the method may further include bending the second electrode plate, and the formation of the second joint portion may be performed after the bending of the second electrode plate.

[0017] According to the manufacturing method of the energy storage element described in (4) above, the second joint portion is formed after the second electrode plate is bent. By bending the second electrode plate in this manner, the second electrode plate can be easily brought close to the second current collector when the second joint portion is formed. This makes it easier to join the second electrode plate and the second current collector, and therefore makes it easier to form the second joint portion.

[0018] (5) In the method for manufacturing an energy storage element described in any one of (1) to (4) above, the first electrode plate may be a positive electrode plate, the second electrode plate may be a negative electrode plate, the first current collector may be a positive electrode current collector, and the second current collector may be a negative electrode current collector.

[0019] According to the manufacturing method of the energy storage element described in (5) above, a first joint is formed by sandwiching and joining a positive electrode plate (first electrode plate) and a positive electrode current collector (first current collector) from both sides, and a second joint is formed by joining a negative electrode plate (second electrode plate) and a negative electrode current collector (second current collector) from one side. Here, when performing the joining operation by accessing from one side, it is difficult to apply a large load, so there is a risk of poor joining. This risk may be more pronounced when joining a positive electrode plate. Therefore, by sandwiching and joining a positive electrode plate (first electrode plate) and a positive electrode current collector (first current collector) from both sides, this risk can be reduced while improving the flexibility of the joining operation between the electrode assembly and the current collector.

[0020] (6) An energy storage element according to one aspect of the present invention comprises an electrode body having a first electrode plate and a second electrode plate, a first current collector joined to the first electrode plate, and a second current collector joined to the second electrode plate, wherein a first joint is formed between the first electrode plate and the first current collector by resistance welding or ultrasonic welding, and a second joint is formed between the second electrode plate and the second current collector by laser welding.

[0021] In an energy storage element according to one embodiment of the present invention, a first joint portion is formed between the first electrode plate and the first current collector by resistance welding or ultrasonic welding, and a second joint portion is formed between the second electrode plate and the second current collector by laser welding. In this manner, the first joint portion and the second joint portion are formed by different joining methods. This allows the electrode body and the current collector to be joined by a joining method that is appropriate for the state of the joining location, etc., during the joining operation, thereby improving the flexibility of the joining operation between the electrode body and the current collector.

[0022] 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.

[0023] In the following description and drawings, the X-axis direction is defined as the direction in which a pair of short sides of the container of the energy storage element face each other, the direction in which a pair of terminals (positive and negative electrodes; the same applies hereinafter) of the energy storage element are aligned, the direction in which a pair of current collectors are aligned, the winding axis direction of the electrode assembly, or the direction in which a first joint and a second joint are aligned. 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 a pair of long sides of the container face each other, the direction in which two electrode assemblies are aligned, or the thickness direction of one electrode assembly. The Z-axis direction is defined as the direction in which the container body and lid of the container are aligned, the direction in which the electrode assembly and terminals are aligned, the direction in which the terminals protrude from the container, 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.

[0024] 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. Simply referring to the X-axis direction refers to both or either of the positive X-axis direction and the negative X-axis direction. The same applies to the Y-axis and Z-axis directions. Below, the X-axis direction may be referred to as a predetermined direction. Expressions indicating relative directions or attitudes, such as parallel and perpendicular, may also include cases where the directions or attitudes are not strictly the same. Two directions being parallel (or perpendicular) does not only mean that the two directions are completely parallel (or perpendicular), but also means that the directions are substantially parallel (or perpendicular), i.e., there is a difference of, for example, a few percent. In the following description, the term "insulating" means "electrically insulating." An insulating material has a volume resistivity of 1×10 １０ It is preferable that the material be made of a material with a resistance of Ωm or more.

[0025] (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.

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

[0027] The energy storage element 10 is not limited to a non-aqueous electrolyte secondary battery, and may be a secondary battery other than a non-aqueous electrolyte secondary battery, or may be a capacitor. The energy storage element 10 may be a primary battery instead of a secondary battery. The energy storage element 10 may be a battery using a solid electrolyte. The energy storage element 10 may be a pouch-type energy storage element. In the present embodiment, the energy storage element 10 is illustrated as having a rectangular parallelepiped shape (square) 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.

[0028] As shown in FIG. 1 , the energy storage element 10 includes a container 100 and a pair of (positive and negative) terminals 200. As shown in FIGS. 2 to 4 , the energy storage element 10 further includes an electrode assembly 300 and a pair of (positive and negative) current collectors 400, which are housed inside the container 100. The energy storage element 10 also includes a pair of (positive and negative) gaskets disposed between the container 100 and the terminals 200 and between the container 100 and the current collectors 400, but these are not shown. An electrolyte solution (nonaqueous electrolyte) is sealed inside the container 100, but this is not shown. There are no particular limitations on the type of electrolyte solution, and various types can be selected as long as they do not impair the performance of the energy storage element 10. In addition to the above components, the energy storage device 10 may also include spacers arranged on the sides or below the electrode body 300, an insulating film that wraps the electrode body 300, and the like.

[0029] [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 body 120 that closes the opening of the container body 110.

[0030] The container body 110 is a rectangular cylindrical member with a bottom that constitutes the main body of the container 100. The container body 110 has a pair of long side walls 111 on both sides in the Y-axis direction (long sides), a pair of short side walls 112 on both sides in the X-axis direction (short sides), and a bottom wall 113 on the surface in the negative Z-axis direction (bottom surface) (see FIG. 2). The long side walls 111 are flat, rectangular walls extending in the X-axis direction. The short side walls 112 are flat, rectangular walls extending in the Z-axis direction. The bottom wall 113 is a flat, rectangular wall extending in the X-axis direction. The lid 120 is a member that constitutes the lid of the container 100 and is disposed in the positive Z-axis direction of the container body 110. The lid 120 is a flat, rectangular wall extending in the X-axis direction. Depending on the shape of the container 100, the long side wall portion 111 may be longer in the Z-axis direction, the short side wall portion 112 may be longer in the Y-axis direction, or the bottom wall portion 113 may be longer in the Y-axis direction.

[0031] After the electrode assembly 300 and the like 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 (container body 110 and 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 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, a gas exhaust valve for releasing pressure inside the container 100 if the pressure inside the container 100 increases excessively, and the like.

[0032] [1.2 Description of Terminal 200] The terminals 200 are electrode terminals (positive and negative terminals) electrically connected to the electrode assembly 300 via the current collector 400. The terminals 200 are metal members for conducting electricity stored in the electrode assembly 300 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 300. 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 400 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.

[0033] 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).

[0034] [1.3 Description of the Electrode Assembly 300] The electrode assembly 300 is an electricity storage element (power generation element) formed by stacking positive and negative electrode plates and a separator. The electrode assembly 300 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, the winding axis is a straight line that passes through the center of the electrode assembly 300 and is parallel to the X-axis direction. In this embodiment, the electrode assembly 300 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 300 is not particularly limited and may be a substantially cylindrical shape or a substantially elliptical cylindrical shape, and the length of the electrode assembly 300 in the X-axis direction is also not particularly limited. For example, the electrode assembly 300 may be elongated in the Z-axis direction.

[0035] The positive electrode plate is an electrode plate (electrode plate) in which a positive electrode active material layer is formed on the surface of a positive electrode current collector foil (metal foil) in the form of a long strip made of a metal such as aluminum or an aluminum alloy. The negative electrode plate is an electrode plate (electrode plate) in which a negative electrode active material layer is formed on the surface of a negative electrode current collector foil (metal foil) in the form of a long strip made of a metal such as copper or a copper alloy. For the positive electrode current collector foil and the negative electrode current collector foil, any known material can be used as long as it is stable against oxidation-reduction reactions during charge and discharge, such as nickel, iron, stainless steel, titanium, baked carbon, conductive polymers, conductive glass, and Al—Cd alloys. 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 can be any known material as long as it is capable of absorbing and releasing charge-transport ions.

[0036] As a positive electrode active material, LiMPO ４ , LiMSiO ４ , LiMBO ３ (M is one or more transition metal elements selected from Fe, Ni, Mn, Co, etc.), polyanion compounds such as lithium titanate, LiMn ２ O ４ or LiMn １．５ Ni ０．５ O ４ Spinel-type lithium manganese oxides such as LiMO ２ (M is one or more transition metal elements selected from Fe, Ni, Mn, Co, etc.) and the like can be used. Examples of the negative electrode active material include lithium metal, lithium alloys (lithium-silicon, lithium-aluminum, lithium-lead, lithium-tin, lithium-aluminum-tin, lithium-gallium, and lithium metal-containing alloys such as Wood's alloy), alloys capable of absorbing and releasing lithium, carbon materials (graphite, non-graphitizable carbon, easily graphitizable carbon, low-temperature fired carbon, amorphous carbon, etc.), silicon oxides, metal oxides, and lithium metal oxides (Li ４ Ti ５ O １２ etc.), polyphosphate compounds, or Co, commonly called conversion anodes ３ O ４ or Fe ２ Examples of the metal include compounds of transition metals such as P and elements of Groups 14 to 16.

[0037] 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.

[0038] Hereinafter, one of the positive and negative electrode plates will be referred to as the first electrode plate 320, and the other will be referred to as the second electrode plate 330. That is, the first electrode plate 320 and the second electrode plate 330 are one and the other of the positive and negative electrode plates. In the present embodiment, the first electrode plate 320 is a positive electrode plate, and the second electrode plate 330 is a negative electrode plate. The first electrode plate 320 has multiple tabs (positive electrode tabs) protruding in the positive direction of the X-axis. When the first electrode plate 320 is wound, the multiple tabs (positive electrode tabs) that are part of the first electrode plate 320 overlap. The second electrode plate 330 has multiple tabs (negative electrode tabs) protruding in the negative direction of the X-axis. When the second electrode plate 330 is wound, the multiple tabs (negative electrode tabs) that are part of the second electrode plate 330 overlap. As a result, the electrode body 300 is configured to include an electrode body main body 310, portions (multiple tabs) of the first electrode plate 320 that protrude from the electrode body main body 310 in the positive direction of the X-axis, and portions (multiple tabs) of the second electrode plate 330 that protrude from the electrode body main body 310 in the negative direction of the X-axis. In other words, the multiple tabs (positive electrode tabs) extend outward (protrude) from portions of the edge of the electrode body main body 310, and the multiple tabs (negative electrode tabs) extend outward (protrude) from portions of the edge of the electrode body main body 310. The electrode body main body 310 is a portion that constitutes the main body of the electrode body 300, and is an elongated cylindrical portion formed by winding the portions of the positive and negative electrode plates other than the tabs and a separator.

[0039] In this embodiment, the energy storage device 10 includes two electrode bodies 300 (electrode body 301 and electrode body 302). Both electrode body 301 and electrode body 302 are wound electrode bodies formed by winding a positive electrode plate, a negative electrode plate, and a separator. Therefore, the electrode body 301 includes an electrode body main body 311, a portion (multiple tabs) of a first electrode plate 320 protruding from the electrode body main body 311 in the positive direction of the X-axis, and a portion (multiple tabs) of a second electrode plate 330 protruding from the electrode body main body 311 in the negative direction of the X-axis. Here, the portion of the electrode body 301 where the multiple tabs that are part of the first electrode plate 320 are bundled is referred to as the first tab portion 321. The portion of the electrode body 301 where the multiple tabs that are part of the second electrode plate 330 are bundled is referred to as the second tab portion 331. That is, the electrode body 301 is configured to include an electrode body main body portion 311, a first tab portion 321 that protrudes in the positive direction of the X-axis from the electrode body main body portion 311, and a second tab portion 331 that protrudes in the negative direction of the X-axis from the electrode body main body portion 311. In this embodiment, the first tab portion 321 is a positive electrode tab portion (positive electrode tab bundle) in which multiple positive electrode tabs of the electrode body 301 are bundled together, and the second tab portion 331 is a negative electrode tab portion (negative electrode tab bundle) in which multiple negative electrode tabs of the electrode body 301 are bundled together.

[0040] Similarly, the electrode body 302 comprises an electrode body main body 312, a portion (multiple tabs) of a first electrode plate 320 protruding from the electrode body main body 312 in the positive direction of the X-axis, and a portion (multiple tabs) of a second electrode plate 330 protruding from the electrode body main body 312 in the negative direction of the X-axis. A portion of the electrode body 302 where multiple tabs that are part of the first electrode plate 320 are bundled is referred to as a first tab portion 322. A portion of the electrode body 302 where multiple tabs that are part of the second electrode plate 330 are bundled is referred to as a second tab portion 332. In other words, the electrode body 302 is configured to comprise the electrode body main body 312, the first tab portion 322 protruding from the electrode body main body 312 in the positive direction of the X-axis, and the second tab portion 332 protruding from the electrode body main body 312 in the negative direction of the X-axis. In this embodiment, the first tab portion 322 is a positive electrode tab portion (positive electrode tab bundle) in which multiple positive electrode tabs of the electrode body 302 are bundled together, and the second tab portion 332 is a negative electrode tab portion (negative electrode tab bundle) in which multiple negative electrode tabs of the electrode body 302 are bundled together.

[0041] The first electrode plate 320 (first tab portions 321 and 322) is connected (joined) to a first current collector 410 described below, and the second electrode plate 330 (second tab portions 331 and 332) is connected (joined) to a second current collector 420 described below.

[0042] [1.4 Description of the Current Collector 400] The current collectors 400 are conductive current collecting members (positive electrode current collector and negative electrode current collector) that are arranged on both sides of the electrode body 300 in the X-axis direction and are connected (joined) to the electrode body 300 and the terminal 200, electrically connecting the electrode body 300 and the terminal 200. The current collector 400 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 400 has a simple configuration and is easy to manufacture. Because the current collector 400 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 400 (space saving), the capacity of the energy storage element 10 can be improved.

[0043] In this embodiment, two current collectors 400 (a positive electrode current collector 400 and a negative electrode current collector 400) are arranged side by side in the X-axis direction. Hereinafter, one of the two current collectors 400 (the current collector 400 located in the positive direction of the X-axis) will be referred to as a first current collector 410, and the other (the current collector 400 located in the negative direction of the X-axis) will be referred to as a second current collector 420. In this embodiment, the first current collector 410 is the positive electrode current collector 400 (positive electrode current collector), and the second current collector 420 is the negative electrode current collector 400 (negative electrode current collector). The first current collector 410 (positive electrode current collector) is formed of aluminum, an aluminum alloy, or the like, similar to the current collector foil (positive electrode current collector foil) of the first electrode plate 320 of the electrode assembly 300. The second current collector 420 (negative electrode current collector) is formed of copper, a copper alloy, or the like, similar to the current collector foil (negative electrode current collector foil) of the second electrode plate 330 of the electrode assembly 300 .

[0044] As shown in FIG. 4 , the first current collector 410 includes a first terminal connection portion 411 and a first electrode assembly connection portion 412. The first terminal connection portion 411 is a flat, rectangular portion parallel to the XY plane and is connected (joined) to the terminal 200 (first terminal 210). The first terminal connection portion 411 is arranged along the lid 120 and includes a through-hole 401 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 121 of the lid 120 and the through-hole 401 of the first terminal connection portion 411 and crimped together. As a result, the first current collector 410 and the first terminal 210 are fixed to the lid 120. The method of connecting (joining) the first current collector 410 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.

[0045] The first electrode assembly connection portion 412 is a flat, rectangular portion parallel to the YZ plane, and is connected (joined) to the electrode assembly 300. The first electrode assembly connection portion 412 extends in the negative Z-axis direction from the end of the first terminal connection portion 411 in the positive X-axis direction along the short side wall portion 112 of the container body 110 in the positive X-axis direction. The first electrode assembly connection portion 412 is connected (joined) to the first electrode plate 320 of the electrode assembly 300. Specifically, the first electrode assembly connection portion 412 is connected (joined) to the first tab portion 321 of the first electrode plate 320 of the electrode assembly 301 and the first tab portion 322 of the first electrode plate 320 of the electrode assembly 302.

[0046] In the present embodiment, the first electrode assembly connection portion 412 is joined to the first tab portions 321, 322 of the first electrode plate 320 by resistance welding or ultrasonic bonding. As a result, as shown in FIG. 2 , a first joint portion 500 is formed between the first electrode assembly connection portion 412 and the first tab portions 321, 322. Specifically, a first joint portion 501 is formed between the first electrode assembly connection portion 412 and the first tab portion 321, and a first joint portion 502 is formed between the first electrode assembly connection portion 412 and the first tab portion 322. The first joint portion 500 (501, 502) is a joint (joining mark, resistance welding mark, or ultrasonic bonding mark) formed by resistance welding or ultrasonic bonding. In this way, the first electrode plate 320 and the first current collector 410 have the first joint portion 500 joined by resistance welding or ultrasonic bonding.

[0047] Specifically, the first electrode plate 320 is bent toward the first current collector 410, disposed on the outside of the first current collector 410, and joined to the first current collector 410. That is, the first tab portion 321 is bent in the positive Y-axis direction toward the first electrode assembly connection portion 412, disposed in the positive X-axis direction of the first electrode assembly connection portion 412, and joined to the first electrode assembly connection portion 412, forming a first joint portion 501. The first tab portion 322 is bent in the negative Y-axis direction toward the first electrode assembly connection portion 412, disposed in the positive X-axis direction of the first electrode assembly connection portion 412, and joined to the first electrode assembly connection portion 412, forming a first joint portion 502. In this way, the first electrode plate 320 (first tab portions 321 and 322) is joined to the outside of the first current collector 410 (first electrode assembly connecting portion 412) while wrapping around both sides of the first current collector 410 (first electrode assembly connecting portion 412) in the Y-axis direction. As a result, the first joint portions 500 (501, 502) are formed at one end (end in the positive X-axis direction) of the electrode assembly 300 (301, 302) in the predetermined direction (X-axis direction).

[0048] Similar to the first current collector 410, the second current collector 420 includes a second terminal connection portion 421 and a second electrode body connection portion 422. The second terminal connection portion 421 is a flat, rectangular portion parallel to the XY plane, and is connected (joined) to the terminal 200 (second terminal 220). The second terminal connection portion 421 is disposed along the lid 120, and includes a through-hole 401 through which the shaft portion 201 of the second terminal 220 passes. The configuration in which the second terminal connection portion 421 is joined to the second terminal 220 is similar to the configuration in which the first terminal connection portion 411 is joined to the first terminal 210, and therefore a detailed description thereof will be omitted.

[0049] The second electrode assembly connection portion 422 is a flat, rectangular portion parallel to the YZ plane, and is connected (joined) to the electrode assembly 300. The second electrode assembly connection portion 422 extends in the negative Z-axis direction from the end of the second terminal connection portion 421 in the negative X-axis direction along the short side wall portion 112 of the container body 110 in the negative X-axis direction. The second electrode assembly connection portion 422 is connected (joined) to the second electrode plate 330 of the electrode assembly 300. Specifically, the second electrode assembly connection portion 422 is connected (joined) to the second tab portion 331 of the second electrode plate 330 of the electrode assembly 301 and the second tab portion 332 of the second electrode plate 330 of the electrode assembly 302.

[0050] In the present embodiment, the second electrode assembly connection portion 422 is joined to the second tab portions 331, 332 of the second electrode plate 330 by laser welding. As a result, as shown in FIG. 3 , a second joint portion 600 is formed between the second electrode assembly connection portion 422 and the second tab portions 331, 332. Specifically, a second joint portion 601 is formed between the second electrode assembly connection portion 422 and the second tab portion 331, and a second joint portion 602 is formed between the second electrode assembly connection portion 422 and the second tab portion 332. The second joint portions 600 (601, 602) are joints (joint marks, laser welding marks) formed by laser welding. In this way, the second electrode plate 330 and the second current collector 420 have the second joint portion 600 joined by laser welding.

[0051] Specifically, the second electrode plate 330 is bent toward the second current collector 420, disposed on the outside of the second current collector 420, and joined to the second current collector 420. That is, the second tab portion 331 is bent in the positive Y-axis direction toward the second electrode assembly connection portion 422, disposed in the negative X-axis direction of the second electrode assembly connection portion 422, and joined to the second electrode assembly connection portion 422, thereby forming a second joint portion 601. The second tab portion 332 is bent in the negative Y-axis direction toward the second electrode assembly connection portion 422, disposed in the negative X-axis direction of the second electrode assembly connection portion 422, and joined to the second electrode assembly connection portion 422, thereby forming a second joint portion 602. In this way, the second electrode plate 330 (second tab portions 331 and 332) is joined to the outside of the second current collector 420 (second electrode assembly connecting portion 422) while wrapping around both sides of the second current collector 420 (second electrode assembly connecting portion 422) in the Y-axis direction. As a result, the second joint portions 600 (601, 602) are formed at the other end (end in the negative X-axis direction) of the electrode assembly 300 (301, 302) in the predetermined direction (X-axis direction).

[0052] [2. Description of Manufacturing Method of Energy Storage Element 10] Next, the manufacturing method of the energy storage element 10 according to the present embodiment will be described in detail with reference to FIGS. 5 to 10. FIG. 5 is a flowchart showing manufacturing steps in the manufacturing method of the energy storage element 10 according to the present embodiment. FIG. 6 is a perspective view showing a step of attaching the current collector 400 to the terminal 200 in the manufacturing method of the energy storage element 10 according to the present embodiment. FIG. 6 shows a state after the first current collector 410 is attached to the first terminal 210 and the second current collector 420 is attached to the second terminal 220. FIG. 7 is a perspective view showing a step of forming the first bonding portion 500 in the manufacturing method of the energy storage element 10 according to the present embodiment. FIG. 7 shows a state after the first electrode plate 320 (first tab portions 321, 322) and the first current collector 410 (first electrode assembly connection portion 412) are joined to form the first bonding portion 500 (501, 502). FIG. 8 is a cross-sectional view showing a step of forming the first bonding portion 500 in the manufacturing method of the energy storage element 10 according to the present embodiment. 8 shows a process of sandwiching and joining the first electrode plate 320 (first tab portions 321, 322) and the first current collector 410 (first electrode assembly connection portion 412) from both sides to form a first joining portion 500 (501, 502). Fig. 8 shows a cross section of the configuration shown in Fig. 7 taken along a plane parallel to the XY plane including line VIII-VIII.

[0053] FIG. 9 is a perspective view showing a step of bending the first electrode plate 320 and a step of bending the second electrode plate 330 in the manufacturing method of the energy storage device 10 according to this embodiment. FIG. 9( a) shows the state after the first electrode plate 320 (first tab portions 321, 322) has been bent. FIG. 9( b) shows the state after the second electrode plate 330 (second tab portions 331, 332) has been bent. FIG. 10 is a perspective view showing a step of forming the second bonding portion 600 in the manufacturing method of the energy storage device 10 according to this embodiment. FIG. 10( a) shows the process of bonding the second electrode plate 330 (second tab portions 331, 332) and the second current collector 420 (second electrode body connection portion 422). (b) of Figure 10 shows the state after the second electrode plate 330 (second tab portions 331, 332) and the second current collector 420 (second electrode body connection portion 422) have been joined and the second joint portion 600 (601, 602) has been formed.

[0054] As shown in FIG. 5, first, the first current collector 410 and the second current collector 420 are attached to the first terminal 210 and the second terminal 220 (S102: current collector attaching step).

[0055] 6 , a first current collector 410 is attached to the first terminal 210, and a second current collector 420 is attached to the second terminal 220. As described above, the first current collector 410 is joined to the first terminal 210 by crimping or the like, and the second current collector 420 is joined to the second terminal 220 by crimping or the like, and the first current collector 410 and the second current collector 420 are fixed to the lid 120 together with the first terminal 210 and the second terminal 220.

[0056] 5 , next, the first electrode plate 320 and the first current collector 410 are sandwiched and joined from both sides to form the first joint 500 (S104: first joint forming step). As described above, the first electrode plate 320 is a positive electrode plate and the first current collector 410 is a positive electrode current collector. Therefore, in the formation of the first joint 500 (S104), the positive electrode plate and the positive electrode current collector are sandwiched and joined from both sides to form the first joint 500.

[0057] 7 , the electrode body 301 and the electrode body 302 are disposed on either side of the first current collector 410 in the Y-axis direction, with the electrode body 301 and the electrode body 302 extending along the Y-axis direction. The first electrode plates 320 of the electrode bodies 301 and 302 are then joined to the first current collector 410 to form a first joint 500. That is, the first tab portion 321 of the first electrode plate 320 of the electrode body 301 is disposed outside the first electrode assembly connection portion 412 of the first current collector 410 (positive direction of the X-axis), and the first tab portion 321 and the first electrode assembly connection portion 412 are joined to form a first joint 501. The first tab portion 322 of the first electrode plate 320 of the electrode body 302 is disposed outside the first electrode assembly connection portion 412 of the first current collector 410 (positive direction of the X-axis), and the first tab portion 322 and the first electrode assembly connection portion 412 are joined to form a first joint 502.

[0058] More specifically, as shown in FIG. 8A , the first tab portion 321 of the first electrode plate 320 of the electrode assembly 301 is positioned in the positive X-axis direction of the end of the first electrode assembly connection portion 412 of the first current collector 410 in the negative Y-axis direction, and the joining devices 20 (21 and 22) sandwich the first electrode plate 320 from both sides in the X-axis direction. Similarly, the first tab portion 322 of the first electrode plate 320 of the electrode assembly 302 is positioned in the positive X-axis direction of the end of the first electrode assembly connection portion 412 of the first current collector 410 in the positive Y-axis direction, and the joining devices 20 (21 and 22) sandwich the first electrode plate 320 from both sides in the X-axis direction. The joining devices 20 (21 and 22) are devices that join two members by sandwiching them from both sides. In this embodiment, the joining devices 20 (21 and 22) are devices (anvil and horn) that perform ultrasonic bonding (solid-state bonding), but may also be devices (two electrodes) that perform resistance welding (fusion bonding).

[0059] Then, as shown in (b) of Figure 8, the first tab portions 321 and 322 are joined to the first electrode assembly connection portion 412 by the joining device 20 (21 and 22). That is, the first tab portion 321 and the first electrode assembly connection portion 412 are joined by resistance welding or ultrasonic welding to form a first joint portion 501. The first tab portion 322 and the first electrode assembly connection portion 412 are joined by resistance welding or ultrasonic welding to form a first joint portion 502. Then, as shown in (c) of Figure 8, the joining devices 20 (21 and 22) release the first tab portions 321 and 322 and the first electrode assembly connection portion 412 from being sandwiched therebetween, and the joining devices 20 (21 and 22) are removed. Traces (joining marks, welding marks, depressions made when pressed, etc.) of joining by clamping with the joining device 20 (21 and 22) are formed on both surfaces in the X-axis direction of the first electrode plate 320 (first tab portions 321, 322) and the first current collector 410 (first electrode body connection portion 412).

[0060] 5, next, the first electrode plate 320 is bent (S106: first electrode plate bending step). That is, after the first bonding portion 500 is formed (S104), the first electrode plate 320 is bent.

[0061] Specifically, the first electrode plate 320 (first tab portions 321, 322) is bent from the state shown in FIG. 7 to the state shown in FIG. 9A. The electrode body 301, which was disposed in a position extending from the first current collector 410 in the negative Y-axis direction, is bent so that the first tab portion 321 is disposed ...1 is disposed so that the first tab portion 322 is disposed so that the first tab portion 322 is disposed so that the first tab portion 322 is disposed so that the first tab portion 3 That is, by rotating the electrode body main body 312 in the negative X-axis direction while bending the first tab portion 322 around the vicinity of the first joint portion 502, the electrode body main body 312 is disposed in the negative Z-axis direction (between the first current collector 410 and the second current collector 420) of the lid body 120. As a result, the electrode body 301 and the electrode body 302 are aligned in the Y-axis direction.

[0062] 5, next, the second electrode plate 330 is bent (S108: second electrode plate bending step). That is, after the first electrode plate 320 is bent (S106), the second electrode plate 330 is bent.

[0063] Specifically, as shown in (b) of Figure 9 (and (a) of Figure 10), the second electrode plate 330 (second tab portions 331, 332) is bent so that the tip portion of the second electrode plate 330 (second tab portions 331, 332) is positioned outside (in the negative X-axis direction) the second current collector 420. For the electrode body 301, the tip portion of the second tab portion 331 is bent in the positive Y-axis direction so that the tip portion of the second tab portion 331 is positioned outside (in the negative X-axis direction) the second electrode body connection portion 422 of the second current collector 420, and the tip portion of the second tab portion 331 and the second electrode body connection portion 422 are overlapped. For the electrode body 302, the tip of the second tab portion 332 is bent in the negative Y-axis direction so that the tip of the second tab portion 332 is positioned outside (negative X-axis direction) the second electrode body connection portion 422 of the second current collector 420, and the tip of the second tab portion 332 and the second electrode body connection portion 422 are overlapped.

[0064] 5 , next, the second electrode plate 330 and the second current collector 420 are joined from one side to form the second joint 600 (S110: second joint forming step). That is, the formation of the second joint 600 (S110) is performed after the formation of the first joint 500 (S104), after the bending of the first electrode plate 320 (S106), and after the bending of the second electrode plate 330 (S108). As described above, the second electrode plate 330 is a negative electrode plate and the second current collector 420 is a negative electrode current collector. Therefore, in the formation of the second joint 600 (S110), the negative electrode plate and the negative electrode current collector are joined from one side to form the second joint 600.

[0065] 10(a), laser light L is irradiated toward the second electrode plate 330 and the second current collector 420 from one side (negative X-axis direction) of the second electrode plate 330 and the second current collector 420. In other words, laser light L is irradiated toward the second tab portion 331 and the second electrode assembly connection portion 422 from one side (outside, negative X-axis direction) of the second tab portion 331 of the second electrode plate 330 and the second electrode assembly connection portion 422 of the second current collector 420 of the electrode assembly 301. Laser light L is irradiated toward the second tab portion 332 and the second electrode assembly connection portion 422 from one side (outside, negative X-axis direction) of the second tab portion 332 of the second electrode plate 330 and the second electrode assembly connection portion 422 of the second current collector 420 of the electrode assembly 302.

[0066] As a result, as shown in (b) of FIG. 10 , the second tab portion 331 and the second electrode assembly connection portion 422 are joined by laser welding (fusion welding), forming a second joint portion 601. The second tab portion 332 and the second electrode assembly connection portion 422 are joined by laser welding (fusion welding), forming a second joint portion 602. Traces of joining from one side (joining marks, welding marks) are formed on one surface (the surface of the second tab portions 331, 332 in the negative X-axis direction) of the second electrode plate 330 (second tab portions 331, 332) and the second current collector 420 (second electrode assembly connection portion 422). When the second electrode plate 330 (second tab portions 331, 332) and the second current collector 420 (second electrode assembly connection portion 422) are through-welded by laser welding, joint marks (welding marks) are also formed on the surface of the second electrode assembly connection portion 422 in the positive X-axis direction.

[0067] In this way, the first bonding portion 500 and the second bonding portion 600 are formed at both ends in the predetermined direction (X-axis direction) of the electrode body 300. That is, in forming the first bonding portion 500 (S104 in FIG. 5), the first bonding portion 500 is formed at one end (the end in the positive X-axis direction) of the electrode body 300 in the predetermined direction (X-axis direction). In forming the second bonding portion 600 (S110 in FIG. 5), after forming the first bonding portion 500 (S104 in FIG. 5), the second bonding portion 600 is formed at the other end (the end in the negative X-axis direction) of the electrode body 300 in the predetermined direction (X-axis direction).

[0068] [3 Description of Effects] As described above, the manufacturing method for energy storage element 10 according to the embodiment of the present invention includes sandwiching and joining first electrode plate 320 and first current collector 410 from both sides to form first joint portion 500, and joining second electrode plate 330 and second current collector 420 from one side to form second joint portion 600. In this way, first joint portion 500 and second joint portion 600 are formed by different joining methods, such that first electrode plate 320 and first current collector 410 are sandwiched and joined from both sides to form first joint portion 500, and second electrode plate 330 and second current collector 420 are joined from one side to form second joint portion 600. As a result, during the joining operation, a joining method appropriate for the state of the joining portion can be selected to join electrode assembly 300 and current collector 400, thereby improving the flexibility of the joining operation for joining electrode assembly 300 and current collector 400.

[0069] In the manufacturing method of the energy storage element 10, after forming a first bonding portion 500 at one end of the electrode assembly 300, a second bonding portion 600 is formed at the other end of the electrode assembly 300. Here, when forming the first bonding portion 500, the first electrode plate 320 and the first current collector 410 are sandwiched and bonded from both sides, so it is necessary to ensure gaps on both sides of the first electrode plate 320 and the first current collector 410 during the bonding process. When forming the second bonding portion 600, the second electrode plate 330 and the second current collector 420 are bonded from one side, so it is sufficient to ensure a gap on one side of the second electrode plate 330 and the second current collector 420 during the bonding process. In a configuration in which bonding portions are formed at both ends of the electrode assembly 300, performing the bonding process first makes it easier to ensure a gap. For this reason, the first bonding portion 500 is formed before the second bonding portion 600 is formed. In other words, the first bonding portion 500 is formed before the second bonding portion 600 is formed. This allows the first bonding portion 500 to be formed while maintaining a gap between the first electrode plate 320 and the first current collector 410. This further improves the degree of freedom in the bonding operation between the electrode assembly 300 and the current collector 400.

[0070] In the manufacturing method of the energy storage element 10, the first electrode plate 320 is bent after the first joint portion 500 is formed, and the second joint portion 600 is formed after the first electrode plate 320 is bent. In this way, by bending the first electrode plate 320 after forming the first joint portion 500, the second electrode plate 330 can be brought closer to the second current collector 420 when forming the second joint portion 600. This facilitates the joining operation of the second electrode plate 330 and the second current collector 420, and therefore the second joint portion 600 can be easily formed. This further improves the degree of freedom in the joining operation between the electrode body 300 and the current collector 400.

[0071] In the method for manufacturing the energy storage element 10, the second joint portion 600 is formed after bending the second electrode plate 330. By bending the second electrode plate 330 in this manner, the second electrode plate 330 can be easily brought close to the second current collector 420 when forming the second joint portion 600. This makes it even easier to join the second electrode plate 330 and the second current collector 420, and therefore makes it even easier to form the second joint portion 600.

[0072] In the manufacturing method of the energy storage element 10, the positive electrode plate and the positive electrode current collector are sandwiched and joined from both sides to form the first joint 500, and the negative electrode plate and the negative electrode current collector are joined from one side to form the second joint 600. Here, since it is difficult to apply a large load when performing the joining operation from one side, joining is often performed by melting the vicinity of the interface. However, in this case, there is a risk of joint defects such as cracks occurring at the joint portion (the melted portion of the laminate foil). This risk varies depending on the expansion coefficient or strength of the material and may be more pronounced when joining a positive electrode plate (made of aluminum). Therefore, by sandwiching and joining the positive electrode plate and the positive electrode current collector from both sides, this risk can be reduced while further improving the flexibility of the joining operation between the electrode assembly 300 and the current collector 400.

[0073] The electrode body 300 has tab portions (first tab portions 321, 322, second tab portions 331, 332), and the tab portions are joined to the current collector 400 (first current collector 410, second current collector 420). Therefore, when joining the tab portions to the current collector 400, the tab portions can be joined to the current collector 400 by bending them, and therefore the tab portions can be easily joined to the current collector 400.

[0074] The second electrode plate 330 (second tab portions 331, 332) is positioned and joined outside (in the negative X-axis direction) of the second current collector 420 (second electrode assembly connection portion 422). Therefore, when performing laser welding, the second tab portions 331, 332 are easily pressed toward the second electrode assembly connection portion 422. If the second tab portions 331, 332 are positioned inside (in the positive X-axis direction) of the second electrode assembly connection portion 422, the output of the laser light L must be increased, which makes the second tab portions 331, 332 more likely to be damaged. Therefore, by positioning the second tab portions 331, 332 outside (in the negative X-axis direction) of the second electrode assembly connection portion 422, the output of the laser light L can be reduced, thereby suppressing damage to the second tab portions 331, 332.

[0075] In the energy storage element 10 according to the embodiment of the present invention, the first electrode plate 320 and the first current collector 410 are formed with a first joint 500 joined by resistance welding or ultrasonic welding, and the second electrode plate 330 and the second current collector 420 are formed with a second joint 600 joined by laser welding. In this manner, the first joint 500 and the second joint 600 are formed by different joining methods. This allows the electrode assembly 300 and the current collector 400 to be joined by selecting a joining method appropriate for the state of the joining location, etc., during the joining operation, thereby improving the degree of freedom in the joining operation of the electrode assembly 300 and the current collector 400.

[0076] [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.

[0077] The energy storage element 10 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. 11 is a plan view showing an example of an energy storage device 12 according to a modified example of the present embodiment. As shown in FIG. 11 , 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. In other words, the energy storage unit 11 may be referred to as an energy storage device.

[0078] In the above embodiment, the first electrode plate 320 of the electrode body 300 has tab portions (first tab portions 321, 322), and the tab portions are joined to the first current collector 410. However, the first electrode plate 320 does not have to have a tab portion. In this case, the end portion of the electrode body 300 in the positive direction of the X axis (the portion that protrudes in the positive direction of the X axis (outward) from the entire edge of the electrode body main body portion 310) may be joined to the first current collector 410. The same applies to the tab portions (second tab portions 331, 332) of the second electrode plate 330.

[0079] In the above embodiment, the first electrode plate 320 (first tab portions 321, 322) is disposed on the outside (positive direction of the X-axis) of the first current collector 410 (first electrode assembly connection portion 412) and joined thereto, but may be disposed on the inside (negative direction of the X-axis). Similarly, the second electrode plate 330 (second tab portions 331, 332) is disposed on the outside (negative direction of the X-axis) of the second current collector 420 (second electrode assembly connection portion 422) and joined thereto, but may be disposed on the inside (positive direction of the X-axis).

[0080] In the above embodiment, resistance welding or ultrasonic welding is exemplified as a method for sandwiching and joining the first electrode plate 320 and the first current collector 410 from both sides in forming the first joint portion 500 (S104 in FIG. 5 ), but this is not limited thereto. The first electrode plate 320 and the first current collector 410 may be sandwiched and joined from both sides by caulking, joining with bolts and nuts, or other joining methods. Similarly, in forming the second joint portion 600 (S110 in FIG. 5 ), the method for joining the second electrode plate 330 and the second current collector 420 from one side is not limited to laser welding, and various methods can be used as appropriate.

[0081] In the above embodiment, the first bonding portion 500 and the second bonding portion 600 are formed at both ends of the electrode body 300, but the first bonding portion 500 or the second bonding portion 600 may be formed at any position on the electrode body 300.

[0082] In the above embodiment, the order of the steps in the manufacturing method of the energy storage device 10 is not particularly limited. The bending of the second electrode plate 330 (S108 in FIG. 5 ) is not limited to being performed after the bending of the first electrode plate 320 (S106 in FIG. 5 ), and may be performed before the bending of the first electrode plate 320 (S106 in FIG. 5 ) or before the formation of the first bonding portion 500 (S104 in FIG. 5 ). The formation of the second bonding portion 600 (S110 in FIG. 5 ) may be performed before the formation of the first bonding portion 500 (S104 in FIG. 5 ). The formation of the second bonding portion 600 (S110 in FIG. 5 ) may be performed before the bending of the second electrode plate 330 (S108 in FIG. 5 ). In addition, the order of the steps can be changed.

[0083] In the above embodiment, the positive electrode plate and the positive electrode current collector are joined by sandwiching them from both sides, and the negative electrode plate and the negative electrode current collector are joined from one side. However, the negative electrode plate and the negative electrode current collector may be joined by sandwiching them from both sides, and the positive electrode plate and the positive electrode current collector may be joined from one side.

[0084] In the above embodiment, the electrode body 300 (301, 302) is a wound electrode body whose winding axis is parallel to the lid body 120. However, the electrode body 300 may also be a wound electrode body whose winding axis is perpendicular to the lid body 120. The electrode body 300 may be a laminated (stacked) electrode body formed by stacking a plurality of flat electrode plates, or may be a bellows-type electrode body in which electrode plates are folded in a bellows shape, or may be an electrode body of another form.

[0085] In the above embodiment, the energy storage device 10 is provided with two electrode bodies 300, but the number of electrode bodies 300 is not particularly limited, and may be one, or three or more.

[0086] Any combination of the components included in the above-described embodiments and their modifications is also included within the scope of the present invention.

[0087] The present invention can be applied to an electric storage device such as a lithium ion secondary battery and a method for manufacturing the same.

[0088] REFERENCE SIGNS LIST 10 Energy storage element 11 Energy storage unit 12 Energy storage device 20, 21, 22 Bonding device 100 Container 110 Container body 111 Long side wall portion 112 Short side wall portion 113 Bottom wall portion 120 Lid body 121, 401 Through hole 200 Terminal 201 Shaft portion 210 First terminal 220 Second terminal 300, 301, 302 Electrode body 310, 311, 312 Electrode body body portion 320 First electrode plate 321, 322 First tab portion 330 Second electrode plate 331, 332 Second tab portion 400 Current collector 410 First current collector 411 First terminal connection portion 412 First electrode body connection portion 420 Second current collector 421 Second terminal connection portion 422 Second electrode body connecting portion 500, 501, 502 First joining portion 600, 601, 602 Second joining portion

Claims

1. A manufacturing method for an energy storage element comprising an electrode assembly having a first electrode plate and a second electrode plate, a first current collector joined to the first electrode plate, and a second current collector joined to the second electrode plate, the manufacturing method including: sandwiching and joining the first electrode plate and the first current collector from both sides to form a first joint; and joining the second electrode plate and the second current collector from one side to form a second joint.

2. A method for manufacturing a storage element as described in claim 1, wherein in forming the first joint, the first joint is formed at one end of the electrode body in a predetermined direction, and in forming the second joint, after forming the first joint, the second joint is formed at the other end of the electrode body in the predetermined direction.

3. The method for manufacturing a storage element according to claim 2, further comprising bending the first electrode plate after the formation of the first joint portion, and the formation of the second joint portion is performed after the bending of the first electrode plate.

4. The method for producing a storage element according to claim 3, further comprising bending the second electrode plate, and forming the second joint portion after bending the second electrode plate.

5. A method for manufacturing an energy storage element according to any one of claims 1 to 4, wherein the first electrode plate is a positive electrode plate, the second electrode plate is a negative electrode plate, the first current collector is a positive electrode current collector, and the second current collector is a negative electrode current collector.

6. An energy storage element comprising: an electrode body having a first electrode plate and a second electrode plate; a first current collector joined to the first electrode plate; and a second current collector joined to the second electrode plate, wherein a first joint portion joined to the first electrode plate and the first current collector by resistance welding or ultrasonic welding is formed, and a second joint portion joined to the second electrode plate and the second current collector by laser welding is formed.

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