Manufacturing method of power storage element

Abstract

To provide a manufacturing method for a power storage element including a container that houses an electrode assembly.SOLUTION: A container includes: a container body 160 having an opening; and a lid body 170 having two terminals 300 and closing the opening. The manufacturing method according to the present invention includes: when welding the lid body 170 to the opening, exposing a welding point between the lid body 170 and the opening and pressing the lid body 170 toward the container body 160 by using a first jig 910 that covers the two terminals.SELECTED DRAWING: Figure 10

Description

[Technical Field]

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

[0002] Patent Document 1 discloses a sealed battery in which a sealing plate is fitted into the opening of an outer can housing an electrode body and then welded along the boundary between the opening of the outer can and the outer periphery of the sealing plate to join the sealing plate to the opening of the outer can, and a method for manufacturing the same. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-204396 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, there has been a demand for a method for manufacturing an energy storage element with higher reliability.

[0005] Therefore, an object of the present invention is to provide a manufacturing method that can manufacture a highly reliable energy storage element. [Means for solving the problem]

[0006] A manufacturing method for a storage element according to one embodiment of the present invention is a manufacturing method for a storage element including a container that houses an electrode body, the container including a container body having an opening, and a lid body that has two terminals and closes the opening, and the manufacturing method includes, when welding the lid body to the opening, exposing the welding point between the lid body and the opening and pressing the lid body toward the container body with a first jig that covers the two terminals. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a method for manufacturing an energy storage element that can manufacture an energy storage element with high reliability. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view showing the appearance of an energy storage device according to an embodiment. [Figure 2] FIG. 2 is an exploded perspective view showing the components of the energy storage device according to the embodiment. [Figure 3] FIG. 3 is a perspective view showing the configuration of the electrode body according to the embodiment. [Figure 4] FIG. 4 is a perspective view showing a metal plate that becomes a container body according to the embodiment. [Figure 5] FIG. 5 is a perspective view showing a container body before assembly according to the embodiment. [Figure 6] FIG. 6 is a perspective view showing a first jig and a second jig according to the embodiment. [Figure 7] FIG. 7 is a perspective view showing a first jig according to the embodiment. [Figure 8] FIG. 8 is a perspective view showing a state in which the container body is housed in the second jig according to the embodiment and the lid body is positioned relative to the container body. [Figure 9] FIG. 9 is a perspective view showing a state in which the lid body and the container body are fixed together with the first jig and the second jig according to the embodiment and laser welding is performed. [Figure 10] FIG. 10 is a partial cross-sectional view showing a state in which a container body is inserted into a second jig according to the embodiment and a lid body is being pressed by a first jig. [Figure 11] FIG. 11 is a plan view showing the start and end points of a weld according to an embodiment. [Figure 12] FIG. 12 is an enlarged cross-sectional view showing the boundary between the opening of the container body and the lid according to the first modification. [Figure 13] FIG. 13 is a perspective view showing the appearance of an energy storage device according to the second modification. [Figure 14] FIG. 14 is an exploded perspective view showing a container according to the second modification. [Figure 15] FIG. 15 is an explanatory diagram showing a laser welding method in which the container body and the lid body are moved according to Modification 3. In FIG. [Figure 16] FIG. 16 is an explanatory diagram showing a laser welding method in which the container body and the lid body are moved according to the fourth modification. [Figure 17] FIG. 17 is an explanatory diagram of the inside of an energy storage device including energy storage elements according to an embodiment, as viewed from the Z-axis direction. DETAILED DESCRIPTION OF THE INVENTION

[0009] (1) A manufacturing method for a storage element according to one embodiment of the present invention is a manufacturing method for a storage element including a container that houses an electrode body, the container including a container body having an opening, and a lid body having two terminals and closing the opening, the manufacturing method including, when welding the lid body to the opening, exposing the welding point between the lid body and the opening and pressing the lid body toward the container body with a first jig that covers the two terminals.

[0010] According to the manufacturing method of the energy storage element described in (1) above, when the lid body is welded to the opening, the lid body is pressed toward the container body by the weight of the first jig or a separately provided pressure mechanism, so that the lid body is prevented from shifting from the opening during welding. Furthermore, because the two terminals are covered by the first jig, adhesion of spatter caused by welding to the terminals is prevented. These features enable the manufacturing of a highly reliable energy storage element.

[0011] (2) In the method for manufacturing an energy storage element described in (1) above, one of the container body and the lid may include a positioning portion that is engaged with and positioned by the other.

[0012] According to this, one of the container body and the lid has a positioning part that is engaged with and positioned by the other, and this positioning part stabilizes the positions of the container body and the lid, making it less likely for the container body and the lid to become misaligned even during welding, allowing the container body and the lid to be welded more reliably.

[0013] (3) In the manufacturing method of the energy storage element described in (1) or (2) above, the container body has a bottom and a cylindrical wall portion that rises from the entire periphery of the bottom and has the opening at its tip, and the manufacturing method may include, during the welding, clamping the wall portion in the arrangement direction of the two terminals and holding the lid body with the first jig while supporting the container body with a second jig that supports the bottom.

[0014] According to the manufacturing method of the energy storage element described in (3) above, during welding, the second jig supports the container body by clamping the wall portion in the arrangement direction of the terminals and supporting the bottom portion, thereby stably supporting the container body, thereby enabling stable welding and manufacturing of an energy storage element with higher reliability.

[0015] (4) In the method for manufacturing a storage element described in any one of (1) to (3) above, the tip of the wall may include two recesses formed by cutting out a portion of the wall, the lid may have a shape corresponding to the shape of the opening of the wall, and the terminals may be arranged at locations on the lid corresponding to each of the two recesses.

[0016] According to the method for manufacturing an energy storage element described in (4) above, stable welding is possible even for a container in which terminals are arranged at locations corresponding to the recesses of the lid.

[0017] (5) In the method for manufacturing a storage element described in any one of (1) to (4) above, one of the lid body and the first jig may have a protrusion, and the other of the lid body and the first jig may have a positioning recess that contacts the protrusion and performs positioning.

[0018] According to the manufacturing method of the energy storage element described in (5) above, the first jig and the lid are positioned by bringing the protrusion into contact with the positioning recess, so that the welding points can be reliably exposed, thereby enabling stable welding.

[0019] (6) In the method for manufacturing an energy storage element according to any one of (1) to (5) above, the thermal conductivity of the material of the first jig may be greater than the thermal conductivity of the material of the container.

[0020] According to the manufacturing method of the energy storage element described in (6) above, the thermal conductivity of the material of the first jig is greater than that of the material of the container, so that heat generated during welding can be easily dissipated from the first jig. This prevents the lid from becoming excessively hot and deforming during welding. This allows for more stable welding.

[0021] (Embodiment) Hereinafter, a method for manufacturing an energy storage element according to an embodiment of the present invention (including its modified examples) will be described with reference to the drawings. Note that 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 and the like are not strictly illustrated. In each drawing, the same reference numerals are used for identical or similar components. The names of the components (each component) in this embodiment are those used in this embodiment and may differ from the names of the components (each component) in the background art.

[0022] In the following description and drawings, the longitudinal direction of the energy storage element, the direction along the winding axis of the electrode body provided in the energy storage element, and the direction in which two terminals provided in the energy storage element are arranged are defined as the X-axis direction. The thickness direction of the container of the energy storage element is defined as the Y-axis direction. The direction in which the bottom surface of the container body and the top surface of the lid of the container are arranged, or the up-down direction, is defined as the Z-axis direction. These X-axis, Y-axis, and Z-axis directions intersect each other (orthogonal in this embodiment). Note that, depending on the mode of use, the Z-axis may not be the up-down direction, but for convenience of explanation, the following description will be made assuming that the Z-axis is the up-down direction. 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 It is preferable that the material be made of a material with a resistance of Ωm or more.

[0023] In the following description, the positive X-axis direction refers to the direction of the X-axis arrow, and the negative X-axis direction refers to the direction opposite to the positive X-axis direction. The same applies to the Y-axis and Z-axis directions. Furthermore, expressions indicating relative directions or attitudes, such as parallel and perpendicular, also include cases where the direction or attitude is not strictly that. "Two directions are perpendicular" does not only mean that the two directions are completely perpendicular, but also means that the directions are substantially perpendicular, i.e., there is a difference of about a few percent.

[0024] [Energy storage element] First, a schematic configuration of an energy storage device 10 according to the present embodiment will be described. Fig. 1 is a perspective view showing the appearance of an energy storage device 10 according to the embodiment. Fig. 2 is an exploded perspective view showing each component of the energy storage device 10 according to the embodiment.

[0025] The energy storage device 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 device 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 device 10 may also be used as a stationary battery for home or business use.

[0026] 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 not be a secondary battery, but may be a primary battery that allows stored electricity to be used without the user having to charge it. Furthermore, the energy storage element 10 may be an all-solid-state lithium battery using a solid electrolyte, or a polymer lithium battery.

[0027] The energy storage element 10 has a shape in which the length in the X-axis direction is longer than the Y-axis direction, specifically, a rectangular parallelepiped shape (rectangular, square) that is flattened in the Y-axis direction. The energy storage element 10 includes a container 100, a pair of terminals 300, and a pair of external gaskets 400. A pair of internal gaskets 500, a pair of current collectors 600, and an electrode assembly 700 are housed inside the container 100. Specifically, the positive electrode components (such as the terminals 300, external gaskets 400, internal gaskets 500, and current collectors 600; the same applies below) are arranged on a first side surface portion 110 of the container 100 in the positive direction of the X-axis. In other words, the first side surface portion 110 is the range from the end face of the container 100 in the positive direction of the X-axis where the positive electrode components are arranged. The first side surface portion 110 is a portion in the X-axis direction that is within a range of 1% to 10% of the length of the container 100 from the end face of the container 100 in the positive direction of the X-axis.

[0028] The components of the negative electrode are disposed on the second side surface portion 120 in the negative X-axis direction of the container 100. In other words, the second side surface portion 120 is the range from the end surface of the container 100 in the negative X-axis direction where the components of the negative electrode are disposed. The second side surface portion 120 is a region in the X-axis direction that is within a range of 1% to 10% of the length of the container 100 from the end surface of the container 100 in the negative X-axis direction.

[0029] An electrolyte solution (nonaqueous electrolyte) is sealed inside the container 100, but is not shown in the figure. There are no particular restrictions 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, spacers arranged on the sides, above, or below the electrode assembly 700, an insulating film that wraps around the electrode assembly 700, etc. may also be arranged.

[0030] The container 100 is a case having an outer shape (approximately rectangular parallelepiped shape) based on a rectangular parallelepiped shape that is long and flat in the X-axis direction. The length of the container 100 in the X-axis direction is at least three times longer than its length in the Z-axis direction. In FIG. 1, the rectangular parallelepiped shape that serves as the base is indicated by a two-dot chain line L1. Specifically, the container 100 has an outer shape that is long and flat in the X-axis direction, with rectangular notches formed at the top of both ends in the X-axis direction. In other words, the container 100 has an outer shape that has two notches based on a prismatic container (rectangular parallelepiped container). When viewed from the base rectangular parallelepiped shape, each notch can be said to form a first recess 101. A terminal 300 is disposed in the first recess 101.

[0031] Specifically, the first side surface portion 110 has a first upper side surface 111, a first top surface 112, and a first side surface 113, and is elongated in the Z-axis direction when viewed in the X-axis direction. The first upper side surface 111 is disposed on the upper part of the first side surface portion 110, and is a rectangular flat surface parallel to the YZ plane and elongated in the Z-axis direction. The first top surface 112 is a flat surface extending in the positive X-axis direction from the lower end of the first upper side surface 111, and is a rectangular flat surface parallel to the XY plane and elongated in the X-axis direction. The first side surface 113 is a flat surface extending downward from the end of the first top surface 112 in the positive X-axis direction, and is a rectangular flat surface parallel to the YZ plane and elongated in the Z-axis direction.

[0032] The first recess 101 of the first side surface portion 110 is formed by a first upper side surface 111 and a first top surface 112, and is open at its end in the positive Z-axis direction and its end in the positive X-axis direction, penetrating in the Y-axis direction. In other words, the first recess 101 of the first side surface portion 110 is a recess in which the corners of the container 100 in the positive X-axis direction and the positive Z-axis direction are recessed (cut out) in a quadrangular (L-shaped) shape when viewed from the Y-axis direction.

[0033] The second side surface portion 120 has a second upper side surface 121, a second top surface 122, and a second side surface 123, and is elongated in the Z-axis direction when viewed from the X-axis direction. The second upper side surface 121 is disposed at the top of the second side surface portion 120, and is a rectangular flat surface parallel to the YZ plane and elongated in the Z-axis direction. The second top surface 122 is a flat surface extending in the negative X-axis direction from the lower end of the second upper side surface 121, and is a rectangular flat surface parallel to the XY plane and elongated in the X-axis direction. The second side surface 123 is a flat surface extending downward from the end of the second top surface 122 in the negative X-axis direction, and is a rectangular flat surface parallel to the YZ plane and elongated in the Z-axis direction.

[0034] The first recess 101 of the second side surface portion 120 is formed by a second upper side surface 121 and a second top surface 122, and is open at its end in the positive Z-axis direction and its end in the negative X-axis direction, penetrating in the Y-axis direction. In other words, the first recess 101 of the second side surface portion 120 is a recess in which the corners of the container 100 in the negative X-axis direction and the positive Z-axis direction are recessed (cut out) into a quadrangular shape when viewed from the Y-axis direction.

[0035] In this container 100, both end faces opposing each other in the Y-axis direction are long side faces 130. Each long side face 130 is a flat surface parallel to the XZ plane and elongated in the X-axis direction, and both end portions in the X-axis direction have shapes corresponding to the first side face portion 110 and the second side face portion 120.

[0036] Of the two end faces of the container 100 that face each other in the Z-axis direction, the end face in the positive Z-axis direction is the top face 140, and the end face in the negative Z-axis direction is the bottom face 150. The top face 140 is a rectangular flat surface that is parallel to the XY plane and elongated in the X-axis direction, connecting the upper end of the first upper side face 111 of the first side face portion 110 and the upper end of the second upper side face 121 of the second side face portion 120. The bottom face 150 is a rectangular flat surface that is parallel to the XY plane and elongated in the X-axis direction, connecting the lower end of the first side face 113 of the first side face portion 110 and the lower end of the second side face 123 of the second side face portion 120.

[0037] The container 100 includes a container body 160 and a lid 170, and is formed into a substantially rectangular parallelepiped shape by assembling the container body 160 and the lid 170. The container body 160 includes a pair of long sides 130, a bottom surface 150, a first side surface 113, and a second side surface 123. The lid 170 includes a first upper side surface 111, a first top surface 112, a second upper side surface 121, a second top surface 122, and a top surface 140.

[0038] The container body 160 has a flat, rectangular bottom 161 at the end in the negative Z-axis direction, and a cylindrical wall 162 rising from the entire periphery of the bottom 161. The bottom 161 has a bottom surface 150. An opening 163 is provided at the tip (upper end) of the wall 162. The tip of the wall 162 includes two first recesses 101. The wall 162 has a pair of first wall portions 164 facing each other in the Y-axis direction and a pair of second wall portions 165 facing each other in the X-axis direction. Each first wall portion 164 has a long side surface 130, and the second wall portion 165 facing in the positive X-axis direction has a first side surface 113, and the second wall portion 165 facing in the negative X-axis direction has a second side surface 123.

[0039] The lid 170 is a metal plate having a shape corresponding to the opening 163 of the wall 162. The lid 170 has a first bent plate portion 171 forming the first upper side surface 111 and the first top surface 112 at its end in the positive direction of the X axis, a second bent plate portion 172 forming the second upper side surface 121 and the second top surface 122 at its end in the negative direction of the X axis, and a top wall portion 173 connecting these portions in the middle in the X axis direction. The top wall portion 173 is flat and rectangular and has a top surface 140. Two liquid injection portions 141 are provided on the top surface 140.

[0040] Two liquid injection parts 141 are arranged at both ends in the X-axis direction of top surface 140. The two liquid injection parts 141 are used to inject electrolyte into container 100 during manufacturing, with one liquid injection part 141 being for injecting electrolyte and the other liquid injection part 141 being for venting air. The two liquid injection parts 141 are sealed after injection, but are open before sealing.

[0041] Although not shown, a gas release valve is provided in the container 100. The gas release valve is a safety valve that releases pressure in the container 100 when the pressure inside the container 100 rises excessively.

[0042] With this configuration, the container 100 is structured so that the electrode assembly 700 and the like are housed inside the container body 160, and then the container body 160 and the lid 170 are joined by welding or the like, thereby sealing the interior. The material of the container 100 (container body 160 and lid 170) is not particularly limited, but is preferably a weldable metal such as stainless steel, aluminum, aluminum alloy, iron, or plated steel sheet.

[0043] The terminals 300 are terminals (positive electrode terminal 310 and negative electrode terminal 320) electrically connected to the electrode assembly 700 via the current collector 600. In other words, the terminals 300 are metal members for conducting electricity stored in the electrode assembly 700 to the external space of the energy storage element 10 and for introducing electricity into the internal space of the energy storage element 10 in order to store electricity in the electrode assembly 700. The material of the terminals 300 is not particularly limited, but the terminals 300 (positive electrode terminal 310 and negative electrode terminal 320) are formed from a conductive material such as aluminum, an aluminum alloy, copper, or a copper alloy. The terminals 300 are connected (joined) to the current collector 600 by crimping, welding, or the like, and are attached to the lid 170.

[0044] In this embodiment, the terminal 300 has a terminal body 330 and a shaft 340 protruding from the terminal body 330. The terminal body 330 is a portion that protrudes outward from the terminal installation surface of the container 100. Here, the terminal installation surface is the first upper surface 112 or the second upper surface 122. On either terminal installation surface, the terminal body 330 protrudes outward from the container 100 along the Z-axis direction. Through holes 112a, 122a through which the shaft 340 penetrates are formed in the lid 170 at locations corresponding to each terminal installation surface. The shaft 340 is connected (joined) to the current collector 600 by being crimped while penetrating the terminal installation surface, the external gasket 400, the internal gasket 500, and the current collector 600.

[0045] The current collectors 600 are arranged one on each side of the electrode body 700 in the X-axis direction, connected (joined) to the electrode body 700 and the terminal 300, and are conductive current collecting members (positive electrode current collector 610 and negative electrode current collector 620) that electrically connect the electrode body 700 and the terminal 300. Specifically, the current collector 600 integrally includes a first joint portion 630 that is connected (joined) to a tab portion 720 of the electrode body 700 (described later) by welding, crimping, or the like, and a second joint portion 640 that is connected (joined) to the terminal 300 by crimping, welding, or the like, as described above. The first joint portion 630 and the second joint portion 640 are each flat plate-shaped portions formed by bending a single piece of sheet metal. The material of the current collector 600 is not particularly limited, but the positive current collector 610 is formed of a conductive material such as aluminum or an aluminum alloy, similar to the positive current collector foil 741 of the electrode body 700 described later, and the negative current collector 620 is formed of a conductive material such as copper or a copper alloy, similar to the negative current collector foil 751 of the electrode body 700 described later.

[0046] The outer gasket 400 is a plate-shaped, rectangular insulating sealing member that is disposed between the lid 170 of the container 100 and the terminal 300, and provides insulation and a seal between the lid 170 and the terminal 300. The inner gasket 500 is a plate-shaped, rectangular insulating sealing member that is disposed between the lid 170 and the current collector 600, and provides insulation and a seal between the lid 170 and the current collector 600. The external gasket 400 and the internal gasket 500 are formed from electrically insulating resins such as polypropylene (PP), polyethylene (PE), polystyrene (PS), polyphenylene sulfide resin (PPS), polyphenylene ether (PPE (including modified PPE)), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyether ether ketone (PEEK), tetrafluoroethylene-perfluoroalkyl vinyl ether (PFA), polytetrafluoroethylene (PTFE), polyethersulfone (PES), ABS resin, or composite materials made by adding fillers to these resins.

[0047] [Electrode body] Fig. 3 is a perspective view showing the configuration of an electrode assembly 700 according to an embodiment. Specifically, Fig. 3 shows the configuration in a partially developed state in which the wound state of the electrode plates in the electrode assembly 700 is shown. As shown in Fig. 3, the electrode assembly 700 has a positive electrode plate 740, a negative electrode plate 750, and separators 761 and 762.

[0048] The electrode body 700 is an electricity storage element (power generating element) formed by winding electrode plates and capable of storing electricity. The electrode body 700 has an elongated shape extending in the X-axis direction and has an oval shape when viewed from the X-axis direction. The electrode body 700 has a shape in which the length in the X-axis direction is 300 mm or more, specifically, approximately 500 mm to 1500 mm. Therefore, the length in the X-axis direction of the electrode body 700 is longer than the length in the Z-axis direction. The length in the X-axis direction of the electrode body 700 is three or more times the length in the Z-axis direction. The electrode body 700 has a main body portion 710 and a plurality of tab portions 720 protruding from the main body portion 710. As described above, the tab portions 720 are connected (joined) to the current collector 600. The tab portions 720 are an example of a connection portion connected to the current collector 600.

[0049] Specifically, the multiple tab portions 720 protrude one from each of both end faces in the X-axis direction of the main body portion 710. A positive electrode tab portion 721 is provided on one end face of the main body portion 710 in the positive X-axis direction, and a negative electrode tab portion 722 is provided on the other end face of the main body portion 710 in the negative X-axis direction.

[0050] The positive electrode plate 740 is an electrode plate in which positive electrode active material layers 742 are disposed on both sides of a positive electrode current collector foil 741, which is a long strip of metal foil. Aluminum, an aluminum alloy, or the like is used for the positive electrode current collector foil 741. The negative electrode plate 750 is an electrode plate in which negative electrode active material layers 752 are disposed on both sides of a negative electrode current collector foil 751, which is a long strip of metal foil. Copper, a copper alloy, or the like is used for the negative electrode current collector foil 751. As the positive electrode active material used in the positive electrode active material layer 742 and the negative electrode active material used in the negative electrode active material layer 752, any known material can be used as long as it is capable of absorbing and releasing charge transport ions.

[0051] Positive electrode active materials include polyanion compounds such as LiMPO4, LiMSiO4, and LiMBO3 (M is one or more transition metal elements selected from Fe, Ni, Mn, Co, etc.), lithium titanate, LiMn2O4, and LiMn 1.5 Ni 0.5 Examples of the negative electrode active material that can be used include spinel-type lithium manganese oxides such as LiMO2 (where M is one or more transition metal elements selected from Fe, Ni, Mn, Co, etc.) and lithium transition metal oxides such as LiMO2 having an α-NaFeO2 crystal structure. Examples of the negative electrode active material include lithium metal, alloys capable of absorbing and desorbing lithium, carbon materials (graphite, non-graphitizable carbon, graphitizable carbon, low-temperature fired carbon, amorphous carbon, etc.), and silicon oxides.

[0052] Separators 761 and 762 are microporous sheets made of resin. Any known material can be used as the material for separators 761 and 762 as long as it does not impair the performance of energy storage element 10. Separators 761 and 762 may be made of a woven fabric or nonwoven fabric that is insoluble in organic solvents, a synthetic resin microporous film made of a polyolefin resin such as polyethylene, or the like.

[0053] The electrode assembly 700 is formed by winding a positive electrode plate 740, a negative electrode plate 750, and separators 761 and 762. The electrode assembly 700 is formed by stacking the negative electrode plate 750, the separator 761, the positive electrode plate 740, and the separator 762 in this order and winding them. In this embodiment, the positive electrode plate 740, the negative electrode plate 750, and the separators 761 and 762 are wound around a winding axis L extending in the X-axis direction, thereby forming the wound electrode assembly 700. The winding axis L is an imaginary axis that serves as the central axis when winding the positive electrode plate 740, the negative electrode plate 750, and the separators 761 and 762. In this embodiment, the winding axis is a straight line that passes through the center of the electrode assembly 700 and is parallel to the X-axis direction.

[0054] A plurality of protruding pieces 743 protruding outward are arranged at intervals on the edge of the positive electrode plate 740 in the X-axis positive direction. Similarly, a plurality of protruding pieces 753 protruding outward are arranged at intervals on the edge of the negative electrode plate 750 in the X-axis negative direction. Each of the plurality of protruding pieces 743 is a portion where no positive electrode active material layer is arranged and the positive electrode current collector foil 741 is exposed (a portion where no positive electrode active material layer is formed). Each of the plurality of protruding pieces 753 is a portion where no negative electrode active material layer is arranged and the negative electrode current collector foil 751 is exposed (a portion where no negative electrode active material layer is formed). In FIG. 3, the portions where no active material layer is formed (a portion where no positive electrode active material layer is formed, a portion where no negative electrode active material layer is formed) are indicated by diagonal lines.

[0055] When the positive electrode plate 740, the negative electrode plate 750, and the separators 761, 762 are wound, the multiple protruding pieces 743 of the positive electrode plate 740 substantially overlap at the end face (one end face) of the main body portion 710 in the positive direction of the X axis, and the multiple protruding pieces 753 of the negative electrode plate 750 substantially overlap at the end face (the other end face) in the negative direction of the X axis. The portion of the positive electrode plate 740 where the multiple protruding pieces 743 overlap is the positive electrode tab portion 721. In other words, the positive electrode tab portion 721 is a portion where the multiple pieces (protruding pieces 743) of the electrode plates of the same polarity (positive electrode plate 740) of the multiple electrode plates (positive electrode plate 740 and negative electrode plate 750) are stacked.

[0056] Similarly, the portion of the negative electrode plate 750 where the multiple protruding pieces 753 overlap is the negative electrode tab portion 722. In other words, the negative electrode tab portion 722 is a portion where the multiple pieces (protruding pieces 753) provided on the electrode plates of the same polarity (negative electrode plate 750) among the multiple electrode plates (positive electrode plate 740 and negative electrode plate 750) are stacked.

[0057] As described above, the electrode assembly 700 includes a main body portion 710 that constitutes the main body of the electrode assembly 700, and tab portions 720 (positive electrode tab portion 721 and negative electrode tab portion 722) that protrude from each end face in the X-axis direction of the main body portion 710. In other words, the electrode assembly 700 includes a pair of tab portions that are composed of the positive electrode tab portion 721 and the negative electrode tab portion 722.

[0058] The main body portion 710 is an elongated cylindrical portion formed by winding together a portion of the positive electrode plate 740 where the positive electrode active material layer 742 is arranged (formed, coated), a portion of the negative electrode plate 750 where the negative electrode active material layer 752 is arranged (formed, coated), and separators 761, 762. The region of the main body portion 710 where at least one of the positive electrode active material layer 742 and the negative electrode active material layer 752 is laminated is referred to as an active material layer formation portion. The outer surface of the main body portion 710 has curved portions 711 at both ends in the Z-axis direction and flat portions 712 at both ends in the Y-axis direction.

[0059] The curved portion 711 is a portion that extends in the X-axis direction and protrudes in a curved shape in the Z-axis direction. When viewed from the X-axis direction, the curved portion 711 is curved in a semicircular arc shape. The flat portion 712 is a flat portion that extends in the X-axis direction and is parallel to the XZ plane connecting the ends of the pair of curved portions 711. In the flat portion 712, a plurality of wound electrode plates and separators (positive electrode plate 740, negative electrode plate 750, separators 761, 762) are stacked in the Y-axis direction.

[0060] The shape of the electrode body is not limited to a wound type, but may be a stack type in which flat electrode plates are stacked, or a shape in which the electrode plates and / or separators are folded in an accordion-like manner (a form in which the separator is folded in an accordion-like manner to sandwich a rectangular electrode plate, a form in which the electrode plate and separator are stacked and then folded in an accordion-like manner, etc.).

[0061] [Method of manufacturing an energy storage element] Next, a method for manufacturing the energy storage element 10 will be described. In this manufacturing method, metal sheets are laser-welded together, but welding methods other than laser welding can also be used as long as they can weld the metal sheets together. Other welding methods include electron beam welding and plasma arc welding.

[0062] The container body 160 and the lid 170 are formed in separate steps. First, the step of forming the container body 160 will be described. FIG. 4 is a perspective view showing a metal plate 190 that becomes the container body 160 according to the embodiment. As shown in FIG. 4, the metal plate 190 is a flat metal plate based on a rectangular plate shape. Each of the four corners of the metal plate 190 is cut out in a rectangular shape. The dashed line L2 shown in FIG. 4 is a line that separates the bottom 161 and the pair of first wall portions 164, and by bending along this dashed line L2, each first wall portion 164 becomes shaped to stand up relative to the bottom 161.

[0063] 5 is a perspective view showing the container body 160 before assembly according to the embodiment. As shown in FIG. 5, a rectangular metal plate 191 that will become the second wall portion 165 in the positive direction of the X-axis and a rectangular metal plate 192 that will become the second wall portion 165 in the negative direction of the X-axis are welded to the bent metal plate 190. Specifically, the metal plate 191 is assembled to the end of the metal plate 190 in the positive direction of the X-axis, and the boundary portion thereof is laser-welded to join the metal plates 190 and 191 together. Similarly, the metal plate 192 is assembled to the end of the metal plate 190 in the negative direction of the X-axis, and the boundary portion thereof is laser-welded to join the metal plates 190 and 192 together. In this way, the container body 160 is formed (see FIG. 2).

[0064] The process of forming the lid 170 will be described. A rectangular flat metal plate that is long in the X-axis direction is prepared, and the metal plate is press-formed to form the lid 170. The terminals 300, the external gaskets 400, the internal gaskets 500, the current collectors 600, and the electrode assembly 700 are attached to the lid 170. Thereafter, the lid 170 is aligned with the opening 163 of the container body 160 so that the internal gaskets 500, the current collectors 600, and the electrode assembly 700 are housed within the container body 160.

[0065] During this alignment, a first jig 910 and a second jig 920 are used to weld the container body 160 and the lid 170 together. Fig. 6 is a perspective view showing the first jig 910 and the second jig 920 according to the embodiment. Fig. 7 is a perspective view showing the first jig 910 according to the embodiment. Fig. 7 is a perspective view of the first jig 910 viewed from the opposite direction to that of Fig. 6.

[0066] 6 and 7, the first jig 910 is a jig that presses the lid 170 against the container body 160. The first jig 910 is a metal member that is long in the X-axis direction. Specifically, the first jig 910 has a pair of end portions 911 that are both ends in the X-axis direction, and an intermediate portion 913 that connects the pair of end portions 911.

[0067] The end 911 in the positive direction of the X-axis is a portion that presses against the first upper surface 112 of the lid 170, and the end 911 in the negative direction of the X-axis is a portion that presses against the second upper surface 122 of the lid 170. An accommodating recess 914 that accommodates the terminal 300 and the external gasket 400 is formed on the lower surface (the surface in the negative direction of the Z-axis) of each end 911. The accommodating recess 914 is formed in a shape that does not interfere with the terminal 300 and the external gasket 400.

[0068] Intermediate portion 913 is a portion that presses top surface 140 of lid body 170. Both ends in the X-axis direction of the lower surface of intermediate portion 913 are provided with protrusions 915 that come into contact with liquid injection portion 141 before sealing. Protrusions 915 have a shape that corresponds to the shape of liquid injection portion 141 before sealing. If liquid injection portion 141 before sealing is a cylindrical opening, protrusions 915 are also cylindrical. Therefore, protrusions 915 come into contact with and fit into liquid injection portion 141 over the entire periphery before sealing. This positions first jig 910 relative to lid body 170. In other words, liquid injection portion 141 before sealing is an example of a positioning recess that comes into contact with protrusions 915 and performs positioning.

[0069] As shown in FIG. 6 , the second jig 920 is a metal box with an open end in the positive direction of the Z axis, and the container body 160 is housed therein. Specifically, the second jig 920 includes a rectangular bottom wall 921 that is long in the X axis direction and a cylindrical side wall 922 that rises from the entire periphery of the bottom wall 921. The bottom wall 921 has a shape that corresponds to the bottom 161 of the container body 160. The side wall 922 includes a pair of first walls 923 that face each other in the Y axis direction and a pair of second walls 924 that face each other in the X axis direction. Each first wall 923 has a shape that corresponds to the first wall portion 164 of the container body 160. Specifically, each first wall 923 has a shape based on a rectangle that is long in the X axis direction, and corners facing the positive X axis direction and the positive Z axis direction and corners facing the negative X axis direction and the positive Z axis direction are cut out to form a quadrangle when viewed from the Y axis direction. Each first wall 923 is formed to have a length in the Z-axis direction shorter than that of the first wall portion 164 .

[0070] Each second wall 924 has a shape corresponding to the second wall portion 165 of the container body 160, but is formed to have a shorter length in the Z-axis direction than the second wall portion 165.

[0071] The thermal conductivity of the material of the first jig 910 and the second jig 920 is preferably greater than the thermal conductivity of the material of the container 100. Specifically, when the container 100 is made of aluminum, the first jig 910 and the second jig 920 are made of copper, which has a higher thermal conductivity than aluminum. The materials of the container 100 and the first jig 910 and the second jig 920 are not limited to this. The first jig 910 and the second jig 920 may be made of different materials.

[0072] 8 is a perspective view showing a state in which the container body 160 is housed in a second jig 920 according to the embodiment and the lid 170 is positioned relative to the container body 160. As shown in FIG. 8, when the container body 160 is housed in the second jig 920, the bottom 161 of the container body 160 is supported by the bottom wall 921 of the second jig 920, and the leading end of the container body 160 in the positive direction of the Z axis is exposed from the second jig 920. In other words, the entire periphery of the boundary between the opening 163 of the container body 160 and the lid 170 is exposed. Furthermore, as described above, the bottom wall 921 has a shape corresponding to the bottom 161 of the container body 160, so that the first walls 923 contact the first wall portions 164, and the second walls 924 contact the second wall portions 165. In this way, the wall portion 162 of the container body 160 is sandwiched between the first walls 923 in the Y-axis direction and between the second walls 924 in the X-axis direction.

[0073] Next, the lid body 170 is pressed with a first jig 910. Specifically, the first jig 910 presses the lid body 170 toward the container body 160 after it has been positioned on the container body 160. Here, the first jig 910 may hold the lid body 170 before positioning, position it on the container body 160, and then press the lid body 170 toward the container body 160. When pressing, as described above, each protrusion 915 of the first jig 910 is fitted into each liquid injection portion 141 of the lid body 170, and the lid body 170 and the first jig 910 are positioned (see FIG. 10 ). In this state, the entire peripheral edge of the lid body 170 and the entire peripheral edge of the opening 163 overlap each other.

[0074] Fig. 9 is a perspective view showing how the lid 170 and the container body 160 are fixed together with a first jig 910 and a second jig 920 according to the embodiment, and how laser welding is performed. Fig. 10 is a partial cross-sectional view showing how the container body 160 is inserted into the second jig 920 according to the embodiment, and the lid 170 is being pressed down by the first jig 910. Here, the weight of the first jig 910 or a pressure mechanism provided in the welding device (not shown) presses the first jig 910 against the lid 170, forming an adhesive surface that is optimal for welding.

[0075] 10 shows a cross-sectional view of first jig 910 and second jig 920, and a plan view of energy storage element 10. In Fig. 10, the shape of the tip end of first wall 923 of second jig 920 in the positive direction of the Z axis is shown by a two-dot chain line L3, and the boundary between lid 170 and opening 163 is shown by a dashed line L4.

[0076] 9 and 10, the boundary between the lid 170 and the opening 163 is exposed by a gap S between the first jig 910 and the second jig 920. Here, the boundary is preferably located at the middle position of the gap S. The length d1 from the boundary to the first jig 910 and the length d2 from the boundary to the second jig 920 are each preferably within 15 mm, more preferably within 10 mm, and even more preferably within 5 mm.

[0077] Final welding is performed in the state shown in FIG. 9 . During final welding, the lid body 170 is pressed toward the container body 160 by the first jig 910, thereby preventing the lid body 170 from shifting position from the opening 163 during final welding. The pressing by the first jig 910 may be performed by the weight of the first jig 910. Furthermore, in a case where the manufacturing apparatus for the energy storage device 10 has a first holding part that holds the first jig 910 and a second holding part that holds the second jig 920, at least one of the first holding part and the second holding part may be moved. This shortens the relative distance between the first jig 910 and the second jig 920, allowing the first jig 910 to press the lid body 170 toward the container body 160.

[0078] In the final welding, the entire peripheral edge of the lid 170 is continuously welded to the entire peripheral edge of the opening 163 all around. Specifically, a movable head 900 that irradiates laser light is positioned near the assembly of the container body 160 and the lid 170. Then, the head 900 irradiates laser light toward the boundary between the lid 170 and the opening 163. While continuing to irradiate laser light, the head 900 is moved in the circumferential direction and its position is changed, thereby continuously laser welding the entire peripheral edge of the lid 170 to the entire peripheral edge of the opening 163 all around (see arrows in FIG. 9 ). The head 900 continues its movement and irradiation without stopping until it completes one revolution, and stops its movement and irradiation when it reaches the starting point 178 of the weld 177 (see FIG. 11 ). During welding, the terminals 300 are accommodated in and covered by the respective accommodation recesses 914 of the first jig 910, thereby preventing spatter from adhering to the terminals 300. Furthermore, the first jig 910 and the second jig 920 are in close contact with the lid 170 and the container body 160, respectively, and are positioned near the welded portion, thereby functioning as a heat sink and stabilizing the heat transfer from the welded portion, thereby achieving a stable welding condition.

[0079] FIG. 11 is a plan view showing the start and end points of weld 177 according to the embodiment. In FIG. 11, the boundary between container body 160 and lid 170 is indicated by a two-dot chain line. As shown in FIG. 11, start point 178 of weld 177 overlaps end point 179 of weld 177. This overlapping portion is an overlapping portion. As described above, the entire periphery of lid 170 is continuously welded around the entire periphery of opening 163, so weld 177 overlaps only in one location. In the overlapping portion, there is a risk that hardened start point 178 may not be sufficiently melted when end point 179 is formed. Therefore, when end point 179 is formed, starting point 178 can be reliably melted by maintaining the irradiation of laser light for a predetermined period of time while the movement of head 900 is stopped.

[0080] Thereafter, the electrolyte is poured into container 100 through pouring portion 141, and when container 100 is filled with the electrolyte, pouring portion 141 is sealed.

[0081] [Effect description] As described above, according to the embodiment, when lid body 170 is welded to opening 163, first jig 910 presses lid body 170 toward container body 160, thereby preventing lid body 170 from shifting position from opening 163 during welding. Furthermore, two terminals 300 are covered by first jig 910, preventing spatter caused by welding from adhering to terminals 300. These factors enable the manufacture of highly reliable energy storage elements 10.

[0082] In the present embodiment, terminal 300 to which a bus bar is joined by welding is exemplified, but the welding to the bus bar may become unstable if spatter adheres to such terminal 300. As described above, the adhesion of spatter to terminal 300 is suppressed, and therefore, it is possible to suppress instability of the welding to the bus bar.

[0083] During welding, the second jig 920 supports the container body 160 by sandwiching the wall portion 162 of the container body 160 in the arrangement direction of the terminals 300 (X-axis direction) and supporting the bottom portion 161, thereby stably supporting the container body 160. This enables stable welding, making it possible to manufacture a more reliable energy storage device 10. In particular, in this embodiment, the wall portion 162 of the container body 160 is sandwiched between the first walls 923 in the Y-axis direction and between the second walls 924 in the X-axis direction, which is preferable because it allows for more stable support of the container body 160. Furthermore, the first walls 923 and the second walls 924 can suppress expansion of the wall portion 162 of the container body 160 over the entire circumference during welding.

[0084] Stable welding is also possible for the container 100 in which the terminals 300 are arranged at positions corresponding to the first recesses 101 of the lid 170.

[0085] By bringing protrusion 915 into contact with injection section 141 (positioning recess), first jig 910 and lid 170 are positioned, so that the welding points can be reliably exposed. Therefore, stable welding is possible.

[0086] Because the thermal conductivity of the material of first jig 910 is greater than that of the material of container 100, heat generated during welding can be easily released from first jig 910. This prevents lid 170 from becoming excessively hot and deforming during welding, allowing for more stable welding.

[0087] Because the thermal conductivity of the second jig 920 is greater than that of the material of the container 100, heat generated during welding can be easily released from the second jig 920. This prevents the container body 160 from becoming excessively hot and deforming during welding, thereby enabling more stable welding.

[0088] [Description of Modifications] The following describes various modifications of the above embodiment. In the following description, the same parts as those in the above embodiment or other modifications are designated by the same reference numerals, and the description thereof may be omitted.

[0089] (Variation 1) In Modification 1, a case will be described in which one of the opening of the container body and the lid is provided with a positioning part that engages with and positions the other. Fig. 12 is an enlarged cross-sectional view showing the boundary between the opening of the container body and the lid according to Modification 1.

[0090] FIG. 12(a) shows an example of Modification 1. As shown in FIG. 12(a), a step 174a1, into which the opening 163 engages, is formed on the entire periphery of the lid 170a1. The opening 163 engages with the step 174a1, thereby positioning the lid 170a1 on the container body 160. In other words, the step 174a1 is an example of a positioning portion. The step 174a1 is a groove cut out into a rectangular shape in cross section, and is continuously formed around the entire periphery of the lid 170a1. When the lid 170a1 is aligned with the opening 163 of the container body 160, the opening 163 fits into the step 174a1. This improves stability during alignment. In this state, the end face of the lid 170a1 in the positive Y-axis direction and the outer surface of the container body 160a1 in the positive Y-axis direction are flush with each other. During welding, a laser beam is irradiated toward the boundary between opening 163 and step portion 174a1 (see arrow L10). At this time, step portion 174a1 blocks the laser beam, so that the laser beam can be prevented from affecting electrode body 700 inside container 100.

[0091] FIG. 12(b) shows an example of Modification 1. As shown in FIG. 12(b), a step 168a2 with which the lid 170 engages is formed in the opening 163a2 of the container body 160a2. The lid 170 engages with the step 168a2, thereby positioning the container body 160a2 relative to the lid 170. In other words, the step 168a2 is an example of a positioning portion. The step 168a2 is a groove cut out in a rectangular shape in cross section, and is formed continuously around the entire periphery of the opening 163a2. When the container body 160a2 is aligned with the lid 170, the lid 170 fits into the step 168a2. This improves stability during alignment. In this state, the end face of the opening 163a2 in the positive Z-axis direction and the outer surface of the lid 170 in the positive Z-axis direction are flush with each other. During welding, a laser beam is irradiated toward the boundary between opening 163a2 and step portion 168a2 (see arrow L10). At this time, step portion 168a2 blocks the laser beam, thereby preventing the laser beam from affecting electrode body 700 inside container 100.

[0092] FIG. 12(c) shows an example of Modification 1. As shown in FIG. 12(c), a protrusion 175a3 that engages with the opening 163 is formed on the entire periphery of the lid 170a3. The protrusion 175a3 may be provided continuously or intermittently along the entire periphery of the lid 170a3. The engagement of the protrusion 175a3 with the opening 163 positions the lid 170a3 on the container body 160. In other words, the protrusion 175a3 is an example of a positioning portion. When the lid 170a3 is aligned with the opening 163 of the container body 160, the opening 163 engages with the protrusion 175a3. This improves stability during alignment. In this state, the end face of the lid 170a3 in the positive Y-axis direction and the outer surface of the container body 160 in the positive Y-axis direction are flush with each other. The protrusion 175a3 blocks the laser light during welding, and therefore, the influence of the laser light on the electrode body 700 inside the container 100 can be suppressed.

[0093] FIG. 12(d) shows an example of Modification 1. As shown in FIG. 12(d), a protrusion 169a4 with which the lid 170 engages is formed on the opening 163a4 of the container body 160a4. The protrusion 169a4 may be provided continuously around the entire periphery of the opening 163a4, or may be provided intermittently. The lid 170 is positioned relative to the container body 160a4 by engaging the protrusion 169a4. In other words, the protrusion 169a4 is an example of a positioning portion. When the container body 160a4 is aligned with the lid 170, the lid 170 is caught by the protrusion 169a4. This improves stability during alignment. In this state, the end face of the opening 163a4 in the Z-axis positive direction and the outer surface of the lid 170 in the Z-axis positive direction are flush with each other. The protrusion 169a4 blocks the laser light during welding, and therefore, the influence of the laser light on the electrode body 700 inside the container 100 can be suppressed.

[0094] As shown in the first modification, the direction of irradiation of the laser light can be changed as appropriate depending on the alignment state between the container body and the lid.

[0095] (Variation 2) In the second modification, a container will be described in which two second recesses are formed by cutting out parts of the wall at the end (base end) on the bottom side of the wall.

[0096] Fig. 13 is a perspective view showing the appearance of an energy storage device 10b according to Modification 2. As shown in Fig. 13, in a container body 160b of a container 100b provided in the energy storage device 10b, a base end portion of a wall portion 162b includes two second recesses 102b. The two second recesses 102b are arranged at both ends of the container body 160b in the X-axis direction and penetrate the container body 160b in the Y-axis direction. Each second recess 102b is a recess that is recessed (cut out) in a quadrangular (L-shaped) shape when viewed in the Y-axis direction.

[0097] FIG. 14 is an exploded perspective view showing a container 100b according to Modification 2. In FIG. 14, components other than the container 100b are not shown. As shown in FIG. 14, a metal plate 190b is formed by bending a flat metal plate. Notches that become a first recess 101b and a second recess 102b are formed at both end portions in the X-axis direction of the bent metal plate 190b. Metal plates 191b and 192b that are bent to correspond to the shapes of the end portions are welded to both end portions in the X-axis direction of the bent metal plate 190b, thereby forming a container body 160b having a cylindrical wall portion 162b.

[0098] Thereafter, the lid 170 to which the terminals 300, the external gaskets 400, the internal gaskets 500, the current collectors 600, and the electrode assembly 700 are attached is aligned with the opening 163b of the container body 160b. A first jig 910 and a second jig 920 are used for alignment.

[0099] After alignment, the entire peripheral edge of the lid 170 and the entire peripheral edge of the opening 163b are overlapped. In this state, final welding is performed. In the final welding, the entire peripheral edge of the lid 170 is continuously welded around the entire peripheral edge of the opening 163b. This forms the container 100b. In this way, even when welding the lid 170 to the container body 160b having two first recesses 101b and two second recesses 102b, there is only one overlapping portion, so poor welding can be suppressed.

[0100] (Other variations) Although the energy storage element according to the embodiment of the present invention (including its modified examples, the same applies hereinafter) has been described above, the present invention is not limited to the above-described embodiment. The embodiment disclosed here is an example in all respects, and the scope of the present invention includes all modifications within the meaning and scope of the claims.

[0101] In the above embodiment, the head unit 900 moves relative to the container body 160 and the lid 170. However, any configuration is possible as long as the entire peripheral edge of the lid 170 can be continuously welded around the entire peripheral edge of the opening 163. A movable optical system that reflects the laser light irradiated from a fixed head unit may be provided, and by moving the optical system, the laser light may be continuously irradiated around the entire peripheral edge of the lid 170 and the entire peripheral edge of the opening 163. In this case, the optical system includes at least one mirror, and the irradiation position of the laser light can be controlled by moving the at least one mirror or changing the position of the at least one mirror.

[0102] Furthermore, a movement mechanism may be provided to change the posture and position of the container body 160 and the lid 170 in the aligned state. In this case, the movement mechanism may be used to change the posture and position of the container body 160 and the lid 170, and the laser beam from the head unit may be continuously irradiated around the entire periphery of the lid 170 and the entire periphery of the opening 163. FIG. 15 is an explanatory diagram showing a laser welding method in which the container body 160 and the lid 170 according to Modification Example 3 are moved. The first jig 910 and the second jig 920 are not shown in FIG. 15. The head unit 900c shown in FIG. 15 is fixed and irradiates laser beam in the negative Y-axis direction. In this state, the movement mechanism moves the container body 160 and the lid 170 in the negative X-axis direction in the aligned state. This results in continuous laser welding of the boundary between the container body 160 and the lid 170.

[0103] Fig. 16 is an explanatory diagram showing a laser welding method in which the container body 160 and the lid body 170 according to Modification 4 are moved. In Fig. 16, the first jig 910 and the second jig 920 are not shown. In Modification 4, the lid body 170 is housed in the opening 163 of the container body 160. Therefore, the upper end of the container body 160 and the upper surface of the lid body 170 are flush with each other, and the boundary between them faces upward (in the positive direction of the Z axis). Although not shown, the shape of the first jig is set so as to expose this boundary.

[0104] The head unit 900d is fixed and emits laser light in the negative direction of the Z axis. In this state, the movement mechanism moves the aligned container body 160 and lid body 170 in the negative direction of the X axis. This causes the boundary between the container body 160 and the lid body 170 to be continuously laser welded. In both cases of Figures 11 and 12, at the direction change point, the movement mechanism changes the orientation of the container body 160 and the lid body 170 and then moves the container body 160 and the lid body 170 in a predetermined direction, thereby continuously welding the entire peripheral edge of the lid body 170 to the entire peripheral edge of the opening 163 all around.

[0105] By using at least two of a movable optical system, a movable head, and a moving mechanism, the laser light may be continuously irradiated around the entire periphery of the lid 170 and the entire periphery of the opening 163.

[0106] In the above embodiment, the bottom 161 and the pair of first wall portions 164 are formed by bending the flat metal sheet 190, and the pair of second wall portions 165 are laser-welded to the bottom 161 and the pair of first wall portions 164 to form the container body 160. However, the method for forming the container body is not limited to this. The container body may also be formed by extrusion processing.

[0107] In the above embodiment, the first recess 101 has a rectangular shape when viewed in the Y-axis direction, but the first recess may have any shape as long as it penetrates in the Y-axis direction. Another example of the shape of the first recess is a staircase shape having at least one step. The same applies to the second recess.

[0108] In the above embodiment, the case where protrusion 915 is cylindrical and pre-sealing liquid injection portion 141 is also cylindrical is exemplified. However, as long as the pre-sealing liquid injection portion and protrusion can fit together, their shapes may be any. For example, if the pre-sealing liquid injection portion and protrusion are non-circular cylindrical, misalignment in the rotational direction can be suppressed even if the pre-sealing liquid injection portion and protrusion are a pair.

[0109] In the above embodiment, the case where the lid 170 and the first jig 910 are placed above the container body 160 (in the positive direction of the Z axis) during final welding has been exemplified. However, these orientations may be opposite. That is, the container body 160 may be placed so that the opening 163 faces downward, and the lid 170 and the first jig 910 may be placed below the container body 160 to perform final welding. In this case, the weight of the container body 160 and its contents acts on the lid 170, so that final welding can be performed in a stable state.

[0110] In the above embodiment, the case where the protrusion 915 is provided on the first jig 910 and the positioning recess (pouring portion 141) is provided on the lid 170 has been exemplified. However, the protrusion may be provided on the lid and the positioning recess may be provided on the first jig. If the accommodating recess of the first jig is shaped to come into contact with the terminal and the external gasket, the accommodating recess can be an example of a positioning recess, and the terminal and the external gasket can be an example of a protrusion.

[0111] The energy storage elements of the above-described embodiments and the like 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 included in the energy storage device. FIG. 17 is an explanatory diagram showing an energy storage device 800 including energy storage elements 10 according to the embodiments. As shown in FIG. 17, a plurality of energy storage elements 10 are arranged inside the energy storage device 800. The energy storage device 800 may include bus bars (not shown) that electrically connect the energy storage elements 10. The energy storage device 800 may also include a status monitoring device (not shown) that monitors the status of one or more energy storage elements 10.

[0112] Any combination of the components included in the above-described embodiments and their modifications is also included within the scope of the present invention. [Industrial Applicability]

[0113] The present invention can be applied to a method for manufacturing an electric storage device such as a lithium ion secondary battery. [Explanation of symbols]

[0114] 10, 10b Storage element 100, 100b container 101, 101b First recess (recess) 102b Second recess 110 First side part 141 Injection part (positioning recess) 160, 160a2, 160a4, 160b container body 161 Bottom 162, 162b wall 163, 163a2, 163a4, 163b opening 164 First wall 165 Second wall section 170, 170a1, 170a3 lid body 171, 172 plate part 173 Ceiling wall 174a1, 168a2 Step portion (positioning portion) 175a3, 169a4 Protrusion (positioning part) 300 terminals 400 External Gasket 500 Internal Gasket 600 current collector 700 Electrode body 710 Main body 720 Tab section 800 Electricity storage device 910 First Jig 911 End 913 Middle section 914 Receiving recess 915 Protrusion 920 Second Jig 921 Bottom wall 922 Side wall 923 First wall 924 Second wall S Gap

Claims

1. A method for manufacturing an energy storage element including a container that houses an electrode assembly, The container comprises: a container body having an opening; a cover having two terminals and closing the opening, The manufacturing method includes: When welding the lid body and the opening, a welding portion between the lid body and the opening is exposed, and the lid body is pressed toward the container body by a first jig that covers the two terminals. A method for manufacturing an energy storage element.

2. One of the container body and the lid body has a positioning portion that is engaged with and positioned by the other. A method for manufacturing the energy storage element according to claim 1 .

3. The container body is The bottom and a cylindrical wall portion rising from the entire periphery of the bottom portion and having the opening at a tip thereof; The manufacturing method includes: During the welding, the wall portion is sandwiched in the arrangement direction of the two terminals, and the lid body is held by the first jig in a state in which the container body is supported by a second jig that supports the bottom portion. The method for manufacturing the energy storage element according to claim 1 or 2.

4. a tip end of the wall portion includes two recesses formed by cutting out a part of the wall portion; the cover has a shape corresponding to the shape of the opening in the wall portion, The terminals are arranged at locations on the lid corresponding to the two recesses, respectively. The method for manufacturing the energy storage element according to claim 3 .

5. one of the lid body and the first jig includes a protrusion, The other of the lid body and the first jig includes a positioning recess that contacts the protrusion and performs positioning. The method for manufacturing the energy storage element according to claim 1 or 2.

6. The thermal conductivity of the material of the first jig is greater than the thermal conductivity of the material of the container. The method for manufacturing the energy storage element according to claim 1 or 2.

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