Energy storage element and method for manufacturing the same

Abstract

To provide a power storage element that enables stable gas discharge.SOLUTION: A power storage element 10 includes a metal container 100 having a through hole 171, and a cylindrical gas exhaust portion 200 that penetrates through the through hole 171 and protrudes outward from the container 100 when a gas exhaust valve 210 is closed. The gas exhaust portion 200 is a metal member that is separate from the container 100 and is joined to the container 100.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a power storage element including an electrode body and a method for manufacturing the same.

Background Art

[0002] Conventionally, in a power storage element (battery), there is known one in which a resin-made gas discharge part (gas discharge member) is provided in a resin-made container (resin case) (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, if the gas discharge part is made of resin, it may not withstand high-temperature gas and melt, resulting in gas leakage.

[0005] Therefore, an object of the present invention is to provide a power storage element capable of stable gas discharge.

Means for Solving the Problems

[0006] A power storage element according to an aspect of the present invention includes a metal container having a through hole, and a cylindrical gas discharge part that penetrates the through hole and protrudes outward from the container in a state of being blocked by a gas discharge valve. The gas discharge part is a metal member that is a separate member from the container and is joined to the container.

[0007] A method for manufacturing a power storage element according to an aspect of the present invention is the method for manufacturing the above power storage element. After injecting an electrolytic solution into the container through the through hole, the gas discharge part is arranged so as to block the through hole and joined to the container.

Effects of the Invention

[0008] According to the present invention, it is possible to provide an energy storage element that enables stable gas discharge. [Brief explanation of the drawing]

[0009] [Figure 1] This is a perspective view showing the external appearance of the energy storage element according to the embodiment. [Figure 2] This is an exploded perspective view showing the individual components of the energy storage element according to the embodiment, after disassembly. [Figure 3] This is a perspective view showing the configuration of the electrode body according to the embodiment. [Figure 4] This is a perspective view showing the schematic configuration of the gas discharge section according to the embodiment. [Figure 5] This is a cross-sectional view showing the schematic configuration of the gas discharge section and cover according to the embodiment. [Figure 6] This is a plan view showing a modified container. [Figure 7] This is a plan view showing a container relating to another modified example. [Modes for carrying out the invention]

[0010] An energy storage element according to one aspect of the present invention comprises a metal container having a through hole, and a cylindrical gas discharge portion that penetrates the through hole and protrudes outward from the container when closed by a gas discharge valve, wherein the gas discharge portion is a separate metal member from the container and is joined to the container.

[0011] According to this design, since a cylindrical gas discharge section, which is a separate component, is joined to the through-hole of the metal container, it can withstand high-temperature gases more effectively than a resin gas discharge section. Therefore, gas leakage can be suppressed, and stable gas discharge can be achieved.

[0012] The gas discharge section may be welded or bonded to the container from the outside.

[0013] According to this, since the gas discharge part is welded or adhered to the container outside the container, it is possible to suppress dust caused by welding or adhesion from entering the inside of the container. Therefore, it is possible to improve the reliability of the power storage element.

[0014] A convex portion protruding from the through hole may be formed on the outer peripheral surface of the gas discharge part when viewed in the axial direction of the through hole.

[0015] According to this, since a convex portion protruding from the through hole is formed on the outer peripheral surface of the gas discharge part, when the gas discharge part is passed through the through hole during assembly, the convex portion catches on the container. Thereby, the gas discharge part can be aligned with a predetermined position. Therefore, the gas discharge part can be attached to the container in a stable state, and stable gas discharge can be realized.

[0016] The gas discharge part may have a connection structure to which an exhaust duct is connected.

[0017] According to this, since a connection structure to which an exhaust duct is connected is provided in the gas discharge part, the exhaust duct and the gas discharge part can be stably connected by this connection structure. Therefore, high-temperature gas can be stably discharged from the gas discharge part to the exhaust duct.

[0018] The gas discharge valve may be provided at one end of the gas discharge part.

[0019] According to this, since the gas discharge valve is provided at one end of the gas discharge part, the gas discharge valve can be easily formed in the gas discharge part.

[0020] A method for manufacturing a power storage element according to an aspect of the present invention is the method for manufacturing a power storage element described above, wherein after injecting an electrolytic solution into the container from the through hole, the gas discharge part is arranged so as to close the through hole and joined to the container.

[0021] According to this design, the gas outlet, which is a separate component from the container, is joined to the container. Therefore, it is possible to join the gas outlet to the container after the contents have been placed inside. As a result, after pouring the electrolyte into the container through the through-hole, the through-hole can be sealed with the gas outlet. In other words, the through-hole can be used as both an injection port and an injection port, thus reducing the effort required to form a separate hole for the injection port.

[0022] (Embodiment) The following description of an energy storage element according to an embodiment (including its modifications) of the present invention will be made with reference to the drawings. The embodiments described below are all general or specific examples. The numerical values, shapes, materials, components, arrangement and connection configurations of components, manufacturing processes, and manufacturing process sequences shown in the following embodiments are examples only and are not intended to limit the present invention. Dimensions and other specifications are not precisely illustrated in each figure. The same or similar components are denoted by the same reference numerals in each figure.

[0023] In the following description and drawings, the direction along the winding axis of the electrode body, the direction in which the electrode body extends, or the direction opposite the short side of the container is defined as the X-axis direction. The direction opposite the long side of the container, or the thickness direction of the container, 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 are aligned, or the vertical direction, is defined as the Z-axis direction. The X-axis direction is an example of a predetermined direction. These X-axis, Y-axis, and Z-axis directions intersect (orthogonal in this embodiment) with each other. Note that depending on the usage, the Z-axis direction may not be the vertical direction, but for the sake of explanation below, the Z-axis direction will be described as the vertical direction.

[0024] In the following explanation, for example, the X-axis positive direction refers to the direction of the X-axis arrow, and the X-axis negative direction refers to the opposite direction. The same applies to the Y-axis and Z-axis directions. Furthermore, expressions indicating relative directions or orientations, such as parallel and orthogonal, include cases where they are not strictly those directions or orientations. For example, two directions being orthogonal does not only mean that the two directions are perfectly orthogonal, but also that they are substantially orthogonal, that is, they may include a difference of, for example, a few percent.

[0025] [General explanation of energy storage elements] First, a general description of the energy storage element 10 in this embodiment will be given using Figures 1 and 2. Figure 1 is a perspective view showing the external appearance of the energy storage element 10 according to this embodiment. Figure 2 is an exploded perspective view showing the individual components of the energy storage element 10 according to this embodiment.

[0026] The energy storage element 10 is an energy storage element that can charge electricity from an external source and discharge electricity to the outside, and in this embodiment, it has a substantially rectangular parallelepiped shape. For example, the energy storage element 10 is a battery used for power storage or power supply purposes. Specifically, the energy storage element 10 is used as a battery for driving or starting the engine of mobile vehicles such as automobiles, motorcycles, watercraft, ships, snowmobiles, agricultural machinery, construction machinery, or railway vehicles for electric railways. Examples of automobiles include electric vehicles (EVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and fossil fuel (gasoline, diesel, liquefied natural gas, etc.) vehicles. Examples of railway vehicles for electric railways include electric trains, monorails, linear motor cars, and hybrid trains equipped with both diesel engines and electric motors. The energy storage element 10 can also be used as a stationary battery for household or commercial use.

[0027] Furthermore, the energy storage element 10 is not limited to a non-aqueous electrolyte secondary battery, but may be a secondary battery other than a non-aqueous electrolyte secondary battery, or a capacitor. The energy storage element 10 may not be a secondary battery, but a primary battery that allows the user to use the stored electricity without charging. In addition, the energy storage element 10 may be, for example, an all-solid-state lithium battery using a solid electrolyte, or a polymer lithium battery. Also, the energy storage element 10 may be a pouch-type energy storage element.

[0028] As shown in Figures 1 and 2, the energy storage element 10 comprises a container 100, a pair of electrode terminals 300, and a pair of external gaskets 400. Inside the container 100 are a pair of internal gaskets 500, a pair of current collectors 600, and an electrode body 700. Specifically, the positive electrode components (electrode terminals 300, external gasket 400, internal gasket 500, and current collector 600, etc.; the same applies hereinafter) are arranged at one end of the container 100 in the positive X-axis direction, and the negative electrode components are arranged at the other end of the container 100 in the negative X-axis direction.

[0029] The container 100 contains an electrolyte (non-aqueous electrolyte), but this is not shown in the diagram. There are no particular restrictions on the type of electrolyte, as long as it does not impair the performance of the energy storage element 10, and various types can be selected. In addition to the above components, spacers placed to the side, above, or below the electrode body 700, an insulating film enclosing the electrode body 700, etc., may also be placed inside.

[0030] The container 100 is a case with an external shape that is elongated in the X-axis direction and flattened in the rectangular parallelepiped shape. For example, in the container 100, the length in the X-axis direction is three times or more than the length in the Z-axis direction. In the container 100, the two opposing end faces in the Y-axis direction are each long side faces 130. Each long side face 130 is a plane that is parallel to the XZ plane and elongated in the X-axis direction. In the container 100, the two opposing end faces in the X-axis direction are each short side faces 135. Each short side face 135 is a plane that is parallel to the YZ plane and elongated in the Z-axis direction. In the container 100, of the two opposing end faces in the Z-axis direction, the end face in the Z-axis positive direction is the top surface 140, and the end face in the Z-axis negative direction is the bottom surface 150. The top surface 140 and the bottom surface 150 are planes that are parallel to the XY plane and elongated in the X-axis direction.

[0031] The container 100 has a container body 160 and a lid 170, and when the container body 160 and the lid 170 are assembled, it forms a rectangular parallelepiped shape. The container body 160 has a pair of long sides 130 and a bottom surface 150. The lid 170 has a pair of short sides 135 and a top surface 140.

[0032] Specifically, the container body 160 is a roughly U-shaped sheet metal with an open top when viewed in the X-axis direction. The container body 160 has flat, long sidewalls forming a pair of long sides 130 at both ends in the Y-axis direction, and a flat, rectangular bottom wall forming a bottom surface 150 at the end in the negative Z-axis direction.

[0033] The cover 170 is a roughly U-shaped sheet metal with an open bottom when viewed in the Y-axis direction. The cover 170 has flat, short sidewall portions forming a pair of short sides 135 at both ends in the X-axis direction, and a flat, rectangular top wall portion forming a top surface 140 at the end in the Z-axis positive direction.

[0034] With this configuration, the container 100 is sealed inside by welding or other means to the container body 160 and the lid 170 after the electrode body 700 and other components are housed inside the container body 160. The material of the container 100 (container body 160 and lid 170) is not particularly limited as long as it is metal, but it is preferable that it be a weldable metal such as stainless steel, aluminum, aluminum alloy, iron, or plated steel sheet.

[0035] The top wall of the lid 170 is provided with a gas discharge section 200 that releases pressure if the pressure inside the container 100 rises excessively. The gas discharge section 200 will be described later.

[0036] The electrode terminals 300 are terminals (positive terminal 310 and negative terminal 320) that are electrically connected to the electrode body 700 via the current collector 600. In other words, the electrode terminals 300 are metallic components that lead the electricity stored in the electrode body 700 to the external space of the energy storage element 10, and also introduce electricity into the internal space of the energy storage element 10 in order to store electricity in the electrode body 700. The material of the electrode terminals 300 is not particularly limited, but for example, the electrode terminals 300 (positive terminal 310 and negative terminal 320) are made of conductive material such as aluminum, aluminum alloy, copper, or copper alloy. The electrode terminals 300 are connected (joined) to the current collector 600 by crimping, welding, etc., and are attached to the cover 170.

[0037] In this embodiment, the electrode terminal 300 has a terminal body portion 330 and a shaft portion 340 that protrudes from the terminal body portion 330. The terminal body portion 330 is the portion that protrudes outward from the terminal mounting surface of the container 100. Here, the terminal mounting surface is the area at both ends in the X-axis direction on the top surface 140 of the lid 170. The terminal body portion 330 protrudes outward from the terminal mounting surface of the container 100 along the Z-axis direction. Through holes 112a and 122a are formed in the lid 170 at locations corresponding to each terminal mounting surface, through which the shaft portion 340 passes. The shaft portion 340 is connected (joined) to the current collector 600 by being crimped while passing through the terminal mounting surface, the external gasket 400, the internal gasket 500, and the current collector 600.

[0038] The current collectors 600 are arranged one on each side of the electrode body 700 in the X-axis direction and are conductive current collecting members (positive electrode current collector 610 and negative electrode current collector 620) that are connected (joined) to the electrode body 700 and the electrode terminal 300 to electrically connect the electrode body 700 and the electrode terminal 300. Specifically, the current collector 600 integrally has a first joint portion 630 that is connected (joined) to the connection portion 720 of the electrode body 700 (described later) by welding or crimping, and a second joint portion 640 that is connected (joined) to the electrode terminal 300 by crimping or welding, as described above, and fixed to the cover 170. The first joint portion 630 and the second joint portion 640 are each flat plate-shaped parts and are formed by bending a single sheet of metal.

[0039] The material of the current collector 600 is not particularly limited, but for example, the positive electrode current collector 610 is made of a conductive material such as aluminum or an aluminum alloy, similar to the positive electrode base material 741 of the electrode body 700 described later, and the negative electrode current collector 620 is made of a conductive material such as copper or a copper alloy, similar to the negative electrode base material 751 of the electrode body 700 described later.

[0040] The external gasket 400 is a plate-shaped, rectangular insulating sealing member that is placed between the lid 170 of the container 100 and the electrode terminal 300, and insulates and seals the space between the lid 170 and the electrode terminal 300. The internal gasket 500 is a plate-shaped, rectangular insulating sealing member that is placed between the lid 170 and the current collector 600, and insulates and seals the space between the lid 170 and the current collector 600. The outer gasket 400 and the inner 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 thereof.

[0041] The electrode body 700 is an electrical storage element (power generation element) formed by winding electrode plates, capable of storing electricity. The electrode body 700 has a long 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 extends, for example, 300 mm or more, specifically to about 500 mm to 1500 mm. Therefore, the length of the electrode body 700 in the X-axis direction is longer than the length in the Z-axis direction. For example, the length of the electrode body 700 in the X-axis direction is more than three times the length in the Z-axis direction. The electrode body 700 has a main body portion 710 and a pair of connecting portions 720 protruding from both ends of the main body portion 710, and as described above, the connecting portions 720 are connected (joined) to the current collector 600.

[0042] Specifically, the multiple connection portions 720 protrude from the intermediate portions of both ends of the main body portion 710 in the X-axis direction. For example, a positive electrode connection portion 721 is provided in the intermediate portion of the Z-axis direction on one end face of the main body portion 710 in the X-positive direction, and a negative electrode connection portion 722 is provided in the intermediate portion of the Z-axis direction on the other end face of the main body portion 710 in the X-negative direction. The configuration of such an electrode body 700 will be described in detail below.

[0043] [Explanation of the electrode structure] Figure 3 is a perspective view showing the configuration of the electrode body 700 according to the embodiment. Specifically, Figure 3 shows the configuration of the electrode body 700 with the winding state of the electrode plates partially unwound. As shown in Figure 3, the electrode body 700 has a positive electrode plate 740, a negative electrode plate 750, and separators 761 and 762.

[0044] The positive electrode plate 740 is an electrode plate in which a positive electrode active material layer 742 is formed on the surface of a positive electrode substrate 741, which is a long, strip-shaped metal foil made of aluminum or an aluminum alloy. The negative electrode plate 750 is an electrode plate in which a negative electrode active material layer 752 is formed on the surface of a negative electrode substrate 751, which is a long, strip-shaped metal foil made of copper or a copper alloy. As the positive electrode substrate 741 and the negative electrode substrate 751, any known material that is stable against oxidation-reduction reactions during charging and discharging can be used, such as nickel, iron, stainless steel, titanium, calcined carbon, conductive polymer, conductive glass, and Al-Cd alloy. 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 that is capable of intercalating and deintercalating lithium ions can be used.

[0045] For example, as positive electrode active materials, polyanionic compounds such as LiMPO4, LiMSiO4, LiMBO3 (where M is one or more transition metal elements selected from Fe, Ni, Mn, Co, etc.), lithium titanate, LiMn2O4, and LiMn 1.5 Ni 0.5Spinel-type lithium manganese oxides such as O4, lithium transition metal oxides such as LiMO2 (where M is one or more transition metal elements selected from Fe, Ni, Mn, Co, etc.) can be used. As negative electrode active materials, lithium metals, lithium alloys (lithium-silicon, lithium-aluminum, lithium-lead, lithium-tin, lithium-aluminum-tin, lithium-gallium, and lithium metal-containing alloys such as Wood's alloys), alloys capable of intercalating and deintercalating lithium, carbon materials (e.g., graphite, non-graphitizable carbon, easily graphitizable carbon, low-temperature calcined carbon, amorphous carbon, etc.), silicon oxides, metal oxides, lithium metal oxides (Li4Ti5O 12 Examples include polyphosphate compounds, or compounds of transition metals and group 14 to 16 elements, such as Co3O4 and Fe2P, which are generally called conversion negative electrodes.

[0046] Separators 761 and 762 are microporous sheets made of resin. Any known material can be used for separators 761 and 762, as long as it does not impair the performance of the energy storage element 10. For example, separators 761 and 762 can be woven fabrics, nonwoven fabrics, or synthetic resin microporous membranes made of polyolefin resins such as polyethylene, which are insoluble in organic solvents.

[0047] The electrode body 700 is formed by alternately stacking and winding a positive electrode plate 740, a negative electrode plate 750, and separators 761 and 762. In other words, the electrode body 700 is formed by stacking and winding the negative electrode plate 750, separator 761, positive electrode plate 740, and separator 762 in this order. In this embodiment, the electrode body 700 is a wound-type electrode body formed by winding the positive electrode plate 740, negative electrode plate 750, etc., around a winding axis L extending in the X-axis direction. The winding axis L is a virtual axis that serves as the central axis when winding the positive electrode plate 740, negative electrode plate 750, etc., and in this embodiment, it is a straight line parallel to the X-axis direction that passes through the center of the electrode body 700.

[0048] On one end edge of the positive electrode plate 740 in the winding axis direction (the end edge in the positive X-axis direction), a plurality of outwardly projecting pieces 743 are arranged at predetermined intervals. Similarly, on the other end edge of the negative electrode plate 750 in the winding axis direction (the end edge in the negative X-axis direction), a plurality of outwardly projecting pieces 753 are arranged at predetermined intervals. Each of the projecting pieces 743 and 753 is a portion where an active material layer containing the active material is not formed and the base material layer is exposed (a portion where the active material layer is not formed).

[0049] When the positive electrode plate 740 and the negative electrode plate 750 are wound with the separators 761 and 762, the protruding pieces 743 of the positive electrode plate 740 overlap at one end face of the main body portion 710, and the protruding pieces 753 of the negative electrode plate 750 overlap at the other end face of the main body portion 710. The portion where the protruding pieces 743 of the positive electrode plate 740 overlap is the positive electrode connection portion 721. In other words, the positive electrode connection portion 721 is a portion formed by stacking multiple pieces (protruding pieces 743) of electrodes (positive electrode plate 740) with the same polarity among multiple electrodes (positive electrode plate 740 and negative electrode plate 750).

[0050] Similarly, the portion where the protruding pieces 753 of the negative electrode plate 750 overlap is the negative electrode connection portion 722. In other words, the negative electrode connection portion 722 is a portion formed by stacking multiple pieces (protruding pieces 753) of electrodes (negative electrode plate 750) of the same polarity among a plurality of electrodes (positive electrode plate 740 and negative electrode plate 750).

[0051] Thus, the electrode body 700 has a main body portion 710 that constitutes the body of the electrode body 700, and a plurality of connection portions 720 (positive electrode connection portion 721 and negative electrode connection portion 722) that protrude from each of the two end faces in the X-axis direction from the main body portion 710.

[0052] The main body portion 710 is an elongated cylindrical portion (active material layer forming portion) formed by winding the positive electrode plate 740 and the negative electrode plate 750, where the positive electrode active material layer 742 and the negative electrode active material layer 752 are formed (coated), with the separators 761 and 762. As a result, the main body portion 710 has a pair of curved portions 711 on both sides in the Z-axis direction, and a flat portion 712 that is flat overall between this pair of curved portions 711. It can also be said that the pair of curved portions 711 are positioned to sandwich the flat portion 712 in the Z-axis direction.

[0053] The curved portion 711 is curved in a semicircular arc shape so as to project in the Z-axis direction when viewed from the X-axis direction, and is a curved portion that extends in the X-axis direction, and is positioned opposite the bottom wall portion of the container body 160 and the top wall portion of the lid 170. In other words, the pair of curved portions 711 are portions that are curved so as to project from the flat portion 712 toward the bottom wall portion of the container body 160 and the top wall portion of the lid 170 on both sides in the Z-axis direction when viewed from the X-axis direction.

[0054] The flat section 712 is a rectangular and flat portion that connects the ends of the pair of curved sections 711, extending parallel to the XZ plane oriented in the Y-axis direction, and is positioned opposite the long side walls on both sides of the container body 160 in the Y-axis direction. The flat section 712 is the main part of the electrode body 700, and in this flat section 712, a plurality of wound electrode plates (positive electrode plate 740 and negative electrode plate 750) are stacked in the Y-axis direction. In other words, in the flat section 712, the Y-axis direction is the stacking direction of the plurality of electrode plates. As described above, since the flat section 712 is the main part of the electrode body 700, the main stacking direction of the electrode body 700 is defined as the Y-axis direction.

[0055] Furthermore, the curved shape of the curved portion 711 is not limited to a semicircular arc shape, but may be part of an ellipse or any other shape. The flat portion 712 is not limited to having a flat outer surface facing the Y-axis direction, but may have a slightly concave or slightly bulging outer surface.

[0056] [Gas exhaust section] Next, the gas discharge section 200 will be described. Figure 4 is a perspective view showing the schematic configuration of the gas discharge section 200 according to the embodiment. Figure 5 is a cross-sectional view showing the schematic configuration of the gas discharge section 200 and the cover 170 according to the embodiment. In Figure 5, an exhaust duct 800, which is separate from the energy storage element 10, is also shown.

[0057] As shown in Figures 4 and 5, the gas outlet section 200 is formed entirely of metal in a bottomed cylindrical shape and protrudes outward from the top surface 140 of the lid 170. The material of the gas outlet section 200 is not particularly limited as long as it is metal, but it is preferably a weldable metal such as stainless steel, aluminum, aluminum alloy, iron, or plated steel sheet, and is even more preferable from the viewpoint of joinability if it is made of the same material as the container 100. In particular, it is more preferable that the material of the gas outlet section 200 is a metal material with a melting point higher than the temperature of the high-temperature gas that may be generated inside the container 100.

[0058] Specifically, the gas discharge section 200 is formed in a bottomed cylindrical shape with the end in the positive Z-axis direction as the bottom. In other words, the axial direction of the gas discharge section 200 is parallel to the Z-axis direction. The bottom of the gas discharge section 200 is a gas discharge valve 210 that is thinner than the wall thickness of the cylindrical portion. On the outer circumferential surface of the intermediate portion in the axial direction of the gas discharge section 200, a protrusion 230 is formed that projects outward. The protrusion 230 is formed in an annular (flange-like) shape so as to be continuous around the entire circumference of the gas discharge section 200. The outer circumferential surface of the end in the positive Z-axis direction of the gas discharge section 200 has a connection structure 240 to which an exhaust duct 800 (see Figure 5) is connected. The connection structure 240 is a tapered section whose diameter gradually increases in the negative Z-axis direction. The exhaust duct 800 is, for example, an exhaust duct mounted on an energy storage device that has at least one energy storage element 10. Specifically, the exhaust duct 800 is housed inside the casing of the energy storage device. The exhaust duct 800 has one end connected to the gas discharge section 200 of the energy storage element 10, and the other end connected to an exhaust port provided on the outer casing.

[0059] A through-hole 171 is formed in the center of the top wall of the lid 170 in the X-axis direction, extending in the Z-axis direction. The axial view (Z-axis view) of the through-hole 171 is such that the gas discharge section 200 fits around its entire circumference (circular in this embodiment). The gas discharge section 200 is attached and joined to the lid 170 so as to pass through this through-hole 171. Here, as shown in Figure 5, "penetration" is not limited to the state in which the Z-axis negative end of the gas discharge section 200 protrudes from the through-hole 171, but also includes the state in which the end is flush with the inner surface of the lid 170, and the state in which the gas discharge section 200 overlaps more than half of the through-hole 171 in the Z-axis direction.

[0060] During installation, the end of the gas discharge section 200 in the negative Z-axis direction is inserted into the through hole 171 from the outside of the container 100 and fitted into place. At this time, the protrusion 230 contacts the top surface 140 of the lid 170, positioning the gas discharge section 200. In this state, the protrusion 230 protrudes from the through hole 171 when viewed in the Z-axis direction. The gas discharge section 200 is integrally joined to the container 100 without any gaps by welding or bonding the protrusion 230 continuously around the entire circumference of the lid 170.

[0061] In this method of manufacturing the energy storage element 10, each electrode terminal 300, each external gasket 400, each internal gasket 500, each current collector 600, and the electrode body 700 are assembled to the lid 170, and then the container body 160 and the lid 170 are assembled and welded together. Next, the electrolyte is poured into the container 100 through the through hole 171, and then the gas discharge section 200 is positioned to close the through hole 171 and joined to the lid 170. In this way, before the gas discharge section 200 is attached to the lid 170, the through hole 171 can be used as the electrolyte pouring port, eliminating the need to provide a dedicated pouring port.

[0062] If a malfunction occurs in the energy storage element 10 and high-temperature gas is generated inside the container 100, the gas discharge valve 210 of the gas discharge section 200 opens, and the high-temperature gas is released from the gas discharge section 200 into the exhaust duct 800. Since the gas discharge section 200 is made of metal, it is less likely to melt even when exposed to high-temperature gas.

[0063] [Explanation of effects] As described above, according to the embodiment of the present invention, the energy storage element 10 has a cylindrical gas discharge section 200, which is a separate component, joined to the through hole 171 of the metal container 100. Therefore, it can withstand high-temperature gases more effectively than a resin gas discharge section. Consequently, gas leakage can be suppressed, and stable gas discharge can be achieved.

[0064] Since the gas discharge section 200 is welded or bonded to the container 100 on the outside of the container 100, it is possible to suppress the entry of debris caused by welding or bonding into the inside of the container 100. Therefore, it is possible to improve the reliability of the energy storage element 10.

[0065] Since a protrusion 230 is formed on the outer circumferential surface of the gas discharge section 200, which protrudes from the through hole 171 in an axial view (Z-axis view), when the gas discharge section 200 is passed through the through hole 171 during assembly, the protrusion 230 catches on the lid 170 (container 100). This allows the gas discharge section 200 to be positioned in the predetermined location. Therefore, the gas discharge section 200 can be attached to the lid 170 in a stable state, and stable gas discharge can be achieved.

[0066] Since a connection structure 240 to which the exhaust duct 800 is connected is provided in the gas discharge section 200, this connection structure 240 allows for a stable connection between the exhaust duct 800 and the gas discharge section 200. Therefore, high-temperature gas can be stably discharged from the gas discharge section 200 to the exhaust duct 800.

[0067] Since a gas discharge valve 210 is provided at one end of the gas discharge section 200, the gas discharge valve 210 can be easily formed in the gas discharge section 200.

[0068] Since the gas outlet 200, which is a separate component from the lid 170, is joined to the lid 170, it is possible to join the gas outlet 200 to the lid 170 after the contents have been placed in the container 100. Therefore, after pouring the electrolyte into the container 100 through the through hole 171, the through hole 171 can be closed with the gas outlet 200. In other words, the through hole 171 can be used as both an injection port and an injection port, thus reducing the effort required to form a separate hole for the injection port.

[0069] (others) Although embodiments of the present invention (including modifications thereof; the same applies hereinafter) of energy storage elements have been described above, the present invention is not limited to the above embodiments. The embodiments disclosed herein are illustrative in all respects, and the scope of the present invention includes all modifications in the sense and scope equivalent to the claims.

[0070] In the above embodiment, the case in which the gas exhaust section 200 is welded or bonded to the cover 170 is illustrated, but the gas exhaust section may be joined to the cover by joining methods other than welding or bonding. Other joining methods include screwing and crimping.

[0071] In the above embodiment, the example shown is that the gas discharge section 200 is joined to the container 100 outside the container 100, but the gas discharge section may also be joined to the container inside the container.

[0072] In the above embodiment, a connection structure 240 consisting of a tapered section that gradually increases in diameter in the negative Z-axis direction was illustrated, but the connection structure may be any structure as long as it is connected to the exhaust duct 800. Other structures include screw connection structures, fitting structures, welded structures, adhesive structures, and welding structures. The exhaust duct may also be made of resin or metal.

[0073] In the above embodiment, an example was given in which a gas discharge valve 210 is provided at the end of the gas discharge section 200 in the positive Z-axis direction. However, the gas discharge valve may also be provided at the end of the gas discharge valve in the negative Z-axis direction, or at an intermediate position in the Z-axis direction of the gas discharge valve.

[0074] In the above embodiment, a gas discharge section 200 having a protrusion 230 on its outer surface was illustrated, but a gas discharge section without a protrusion on its outer surface may also be used.

[0075] In the above embodiment, the case in which only one electrode body 700 is housed in the container 100 is illustrated, but multiple electrode bodies may be housed in the container.

[0076] In the above embodiment, a wound-type electrode body 700 was exemplified. However, the shape of the electrode body is not limited to a wound type, and may also be a stacked type in which flat plates are stacked, or a shape in which the plates and / or separators are folded in an accordion shape (a form in which the separator is folded in an accordion shape and a rectangular plate is sandwiched between them, a form in which the plates and separators are stacked and then folded in an accordion shape, etc.). In any case, the stacking direction of the electrode body may be in the Y-axis direction (a predetermined direction). A bipolar type electrode body may also be used.

[0077] In the above embodiment, a power storage element 10 based on a flat rectangular parallelepiped shape was exemplified. However, the shape of the power storage element 10, that is, the shape of the container 100, is not limited to a rectangular parallelepiped shape. It may be based on a polygonal prism shape, an oblong cylinder shape, an elliptical cylinder shape, or a cylindrical shape, etc. In the container, a recess (notch) may be formed in a part of the base shape. In this case, a gas discharge section may be provided within the recess.

[0078] Figure 6 is a plan view showing a modified container 100a. Here, only the end of container 100A in the positive X-axis direction is shown, but the end in the negative X-axis direction may have a similar or different shape. In Figure 6, the contour of the standard shape is shown by the dashed line L1. In the following description, parts identical to those in the above embodiment may be denoted by the same reference numerals and their descriptions may be omitted.

[0079] As shown in Figure 6, the container 100A has a first recess 101a and a second recess 102a formed at the upper and lower ends, respectively, which are rectangular cutouts. Specifically, the first recess 101a has a first recess side surface 103a facing the X-axis plus direction and a recess upper surface 104a facing the Z-axis plus direction. The electrode terminals 300 and the external gasket 400 are arranged on the recess upper surface 104a.

[0080] The second recess 102a has a second recess side surface 105a facing the positive X-axis direction and a recess bottom surface 106a facing the negative Z-axis direction. A through hole (not shown) is formed in the recess bottom surface 106a, and a gas discharge section 200a is provided to close this through hole. Figure 7 is a plan view showing a container 100b according to another modification. As shown in Figure 7, the gas discharge section 200b may be provided on the second side surface 105a.

[0081] The present invention also includes forms constructed by arbitrarily combining the components included in the above embodiments and their modified examples. [Industrial applicability]

[0082] This invention can be applied to energy storage elements such as lithium-ion secondary batteries. [Explanation of symbols]

[0083] 10 Energy storage elements 100, 100a, 100b container 160 Container body 170 Lid 171 Through hole 200, 200a, 200b Gas discharge section 210 Gas discharge valve 230 protrusion 240 Connection Structure 300 electrode terminal 330 Terminal body 340 Shaft section 600 Current collector 610 Positive electrode current collector 620 Negative electrode current collector 700 Electrode body 710 Main Unit 711 Curved section 712 Flat area 720 Connection part 800 Exhaust duct L winding shaft

Claims

1. A metal container having a through hole, The container comprises a cylindrical gas discharge section that penetrates the through-hole and protrudes outward from the container, while being closed by a gas discharge valve, The gas discharge section is a metal member consisting of a single component separate from the container, and is joined to the container. Energy storage element.

2. The gas discharge section is welded or bonded to the container on the outside of the container. The energy storage element according to claim 1.

3. On the outer circumferential surface of the gas discharge section, a protrusion is formed that extends from the through-hole when viewed in the axial direction of the through-hole. The energy storage element according to claim 2.

4. The gas discharge section has a connection structure to which an exhaust duct is connected. The energy storage element according to any one of claims 1 to 3.

5. The gas discharge valve is provided at one end of the gas discharge section. The energy storage element according to any one of claims 1 to 4.

6. A method for manufacturing an energy storage element according to any one of claims 1 to 5, After pouring the electrolyte into the container through the through hole, the gas discharge section is positioned to close the through hole and joined to the container. A method for manufacturing energy storage elements.

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