Energy storage element

Abstract

To provide a power storage element in which a closing member can be easily bonded to a container.SOLUTION: A power storage element 10 comprises: a container 100 on which a liquid port 122 for an electrolyte is formed, and which has a wall part (a lid body 120) extending in a first direction (an X-axis direction); and a closing member 300 which is disposed in a second direction (a Z-axis direction) intersecting the first direction of the wall part in a manner without being fitted into the wall part, and which is bonded to the wall part so as to close the liquid port 122. The closing member 300 is formed such that a distance between the liquid port 122 and a third-direction edge on each of both sides in a third direction (a Y-axis direction) intersecting the first and second directions may be greater than a distance between the liquid port 122 and a first-direction edge on at least one side in the first direction.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to an energy storage device including a container and a closing member that closes a liquid port of the container. [Background technology]

[0002] Conventionally, an electric storage element has been known that includes a container having an opening for an electrolytic solution and a blocking member that blocks the opening. For example, Patent Document 1 discloses a sealed battery (electric storage element) that includes a battery case (container) having an inlet (inlet) and a sealing plug (blocking member) that seals the inlet. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-45888 Summary of the Invention [Problem to be solved by the invention]

[0004] In the energy storage element having the above-described conventional configuration, it may be difficult to join the closing member to the container. For example, in the energy storage element disclosed in Patent Document 1, the small-diameter portion of the sealing plug has an outer diameter that is approximately the same as the diameter of the liquid inlet, and the sealing plug is joined to the battery case by welding with the small-diameter portion of the sealing plug inserted into the liquid inlet. That is, in the energy storage element disclosed in Patent Document 1, the closing member is fixed to the container by fitting (press-fitting) it into the liquid inlet, and the closing member is joined to the container in this state. However, in this case, when the closing member is fitted (press-fitted) into the liquid inlet, the container or the closing member may deform, which may cause poor joining when joining the closing member to the container, making joining difficult.

[0005] The present invention was made by the inventors of the present application by focusing on the above-mentioned problem, and has an object to provide an energy storage element in which a closing member can be easily joined to a container. [Means for solving the problem]

[0006] In order to achieve the above-mentioned object, one embodiment of the present invention provides an energy storage element comprising: a container having a wall portion extending in a first direction and having a liquid inlet for an electrolyte formed therein; and a blocking member arranged in a second direction intersecting the first direction of the wall portion without being engaged with the wall portion, and joined to the wall portion to block the liquid inlet, wherein the distance between the edge of the blocking member in the third direction and the liquid inlet on both sides of a third direction intersecting the first direction and the second direction is greater than the distance between the edge of the first direction and the liquid inlet on at least one side of the first direction.

[0007] According to this, the energy storage element includes a closure member that is joined to the wall portion of the container extending in the first direction without being fitted with the wall portion, and the distance between the edge of the closure member and the liquid port on both sides in the third direction is greater than the distance between the edge of the closure member and the liquid port on at least one side in the first direction. By joining the closure member to the wall portion without being fitted with the wall portion, deformation of the wall portion and the closure member can be suppressed when joining the closure member to the wall portion, and poor joining can be suppressed. Furthermore, because an electrode terminal or a gas exhaust valve, etc., is disposed between the closure member and the short side of the wall portion, it is difficult to access the closure member from the short side of the wall portion, and it is difficult to fix (temporarily fix) the closure member to the wall portion from the short side of the wall portion when joining the closure member to the wall portion. In contrast, the closure member is easily accessible from the long side of the wall portion, and it can be easily fixed (temporarily fixed) to the wall portion from the long side of the wall portion. For this reason, the closing member is arranged so that the distance between the edge and the liquid orifice on both sides in the third direction (the long side sides of the wall portion) is greater than the distance between the edge and the liquid orifice on at least one side in the first direction (the short side sides of the wall portion). This allows the closing member to be easily accessed from both long side sides of the wall portion and temporarily fixed to the wall portion from both long side sides of the wall portion, so that when the closing member is joined to the wall portion, the closing member can be easily and stably temporarily fixed to the wall portion. Therefore, the closing member can be easily and stably temporarily fixed to the wall portion while suppressing the occurrence of joining defects when the closing member is joined to the wall portion, so that the closing member can be easily joined to the container.

[0008] The blocking member may be configured so that the distance between the third direction edge and the liquid port on both sides of the third direction is greater than the distance between the first direction edge and the liquid port on both sides of the first direction.

[0009] If the closure member disposed on the wall of the container is too large, it may cause defects, and therefore, from the viewpoint of parts cost, a smaller size is preferable. Furthermore, since the distance between the edge and the liquid port in the third direction is sufficient for the closure member to be temporarily fixed to the wall, the distance between the edge and the liquid port on both sides in the first direction can be reduced. Therefore, the closure member is formed so that the distance between the edge and the liquid port on both sides in the third direction is greater than the distance between the edge and the liquid port on both sides in the first direction. This prevents the closure member from becoming too large and causing defects, and allows the closure member to be easily and stably temporarily fixed to the wall from both sides in the third direction.

[0010] The blocking member may have a length in the third direction that is longer than a length in the first direction.

[0011] According to this, by making the length of the closing member longer in the third direction than in the first direction, it is possible to easily realize a configuration in which the distance between the edge in the third direction and the liquid orifice is greater than the distance between the edge in the first direction and the liquid orifice. This makes it possible to easily and stably temporarily fix the closing member to the wall portion, and therefore to easily join the closing member to the container.

[0012] The blocking member may have a length in the first direction of an end portion in the third direction that is shorter than a length in the first direction of a central portion in the third direction.

[0013] If the size of the closing member disposed on the wall portion of the container is too large, it may cause a malfunction, and therefore, from the viewpoint of parts cost, a smaller size is preferable. Furthermore, since the end portion of the closing member in the third direction only needs to be large enough to temporarily fix the closing member to the wall portion, the length in the first direction can be shorter than the length in the center portion of the closing member in the third direction. Therefore, the closing member is formed so that the length in the first direction of the end portion in the third direction is shorter than the length in the first direction of the center portion in the third direction. This prevents the closing member from becoming too large and causing malfunctions, and allows the closing member to be easily and stably temporarily fixed to the wall portion from both sides of the wall portion in the third direction.

[0014] The closing member may be joined to the wall portion at a position closer to the liquid orifice than a center position in the third direction between the edge in the third direction and the liquid orifice.

[0015] According to this, by joining the closing member to the wall portion at a position closer to the liquid orifice than the center position in the third direction between the edge in the third direction and the liquid orifice, it is possible to widen the end portion of the closing member for temporarily fixing the closing member to the wall portion during joining, which allows the closing member to be easily and stably temporarily fixed to the wall portion, making it possible to easily join the closing member to the container.

[0016] The closing member may have a shaft portion that is inserted into the liquid port without being fitted into the liquid port.

[0017] According to this, the closure member has a shaft portion through which it is inserted without being fitted into the liquid port, and the wall portion and the closure member are not deformed by fitting, and the closure member can be easily positioned relative to the wall portion. As a result, when joining the closure member to the wall portion, the closure member can be easily positioned on the wall portion, and therefore the closure member can be easily joined to the container.

[0018] The present invention can be realized not only as such an electricity storage element, but also as a combination of a container and a closing member. [Effects of the Invention]

[0019] According to the energy storage device of the present invention, the closing member can be easily joined to the container. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a perspective view showing the appearance of an energy storage element according to an embodiment; [Figure 2] 3A and 3B are perspective views showing the configuration of a closing member provided in an energy storage device according to an embodiment before and after joining to a container. [Figure 3] 3A and 3B are a top view and a cross-sectional view showing the configuration of a closing member according to an embodiment. [Figure 4A] FIG. 10 is a top view showing the configuration of a closing member according to a first modified example of the embodiment. [Figure 4B] FIG. 10 is a top view showing the configuration of a closing member according to a first modified example of the embodiment. [Figure 4C] FIG. 10 is a top view showing the configuration of a closing member according to a first modified example of the embodiment. [Figure 5] FIG. 10 is a cross-sectional view showing the configuration of a blocking member according to a second modified example of the embodiment. [Figure 6] FIG. 10 is a cross-sectional view showing the configuration of a blocking member according to a third modified example of the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0021] Hereinafter, with reference to the drawings, an energy storage element according to an embodiment of the present invention (including its modified examples) will be described. 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 only 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 or similar components are designated by the same reference numerals.

[0022] In the following description and drawings, the arrangement direction of a pair of electrode terminals (positive and negative, hereinafter the same) of the energy storage element, or the direction in which the short side surfaces of the container face each other, is defined as the X-axis direction. The direction in which the long side surfaces of the container face each other, or the thickness direction of the container, is defined as the Y-axis direction. The arrangement direction of the container body and lid of the container, the arrangement direction of the lid and closing member, 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.

[0023] In the following description, for example, 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. When simply referring to the X-axis direction, it refers to both or either of the positive X-axis direction and the negative X-axis direction. The same applies to the Y-axis and Z-axis directions. Hereinafter, the X-axis direction may also be referred to as the first direction, the Z-axis direction as the second direction, and the Y-axis direction as the third direction. Expressions indicating relative directions or orientations, such as "parallel" and "orthogonal," may also include cases where the directions or orientations are not strictly those of the same kind. For example, "two directions are parallel" does not only mean that the two directions are completely parallel, but also means that the directions are substantially parallel, i.e., there is a difference of, for example, a few percent. Furthermore, in the following description, the term "insulation" means "electrical insulation."

[0024] (Embodiment) [1 General Description of Energy Storage Element 10] First, an overall description of an energy storage device 10 according to the present embodiment will be given with reference to Figures 1 and 2. Figure 1 is a perspective view showing the appearance of the energy storage device 10 according to the present embodiment. Figure 2 is a perspective view showing the configuration of a closing member 300 included in the energy storage device 10 according to the present embodiment before and after bonding to the container 100. Specifically, (a) of Figure 2 shows the state before bonding the closing member 300 to the container 100, and (b) of Figure 2 shows the state after bonding the closing member 300 to the container 100.

[0025] The energy storage device 10 is a secondary battery (single cell) that can charge and discharge electricity, specifically a nonaqueous electrolyte secondary battery such as a lithium-ion secondary battery. The energy storage device 10 is used, for example, as a battery for driving or starting the engine of a mobile object such as an automobile, motorcycle, personal watercraft, ship, snowmobile, agricultural machinery, construction machinery, 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 gasoline-powered automobile. 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 can also be used as a stationary battery for home use or a power generator.

[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. The energy storage element 10 may be a battery that uses a solid electrolyte. The energy storage element 10 may also be a pouch-type energy storage element. In this embodiment, the energy storage element 10 is illustrated as having a flat rectangular parallelepiped (square) shape, but the shape of the energy storage element 10 is not limited to a rectangular parallelepiped shape, and may be a cylindrical shape, an elongated cylindrical shape, an elliptical cylindrical shape, a polygonal prism shape other than a rectangular parallelepiped, or the like.

[0027] 1, the energy storage element 10 includes a container 100, a pair of electrode terminals 200 (positive and negative, hereinafter the same), a pair of upper gaskets 210, and a closing member 300. The container 100 contains a pair of lower gaskets, an electrode assembly, a pair of current collectors, an electrolyte (nonaqueous electrolyte), and the like, but these are not shown in the figure. 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.

[0028] In addition to the above components, the energy storage element 10 may also have spacers arranged on the sides or below the electrode body, an insulating film that encases the electrode body, etc. Furthermore, an insulating film (shrink tube, etc.) that covers the outer surface of the container 100 may be arranged around the container 100. The material of the insulating film is not particularly limited as long as it can ensure the insulation required for the energy storage element 10, and examples of the material include insulating resins such as PC, PP, PE, PPS, PET, PBT, and ABS resin, epoxy resin, Kapton, Teflon (registered trademark), silicone, polyisoprene, and polyvinyl chloride.

[0029] The container 100 is a rectangular parallelepiped (square or box-shaped) case having a container body 110 with an opening formed therein and a lid 120 that closes the opening of the container body 110. The container body 110 is a rectangular cylindrical member with a bottom that forms the main body of the container 100, and an opening is formed on the positive side of the Z axis. The lid 120 is a rectangular plate-like member that forms the lid of the container 100, and is disposed so as to extend in the X axis direction (first direction) in the positive direction of the Z axis of the container body 110. The container 100 is configured so that the interior is sealed by accommodating an electrode assembly and the like inside the container body 110 and then joining the container body 110 and the lid 120 by welding or the like. The material of the container 100 (the container body 110 and the lid 120) is not particularly limited, and can be, for example, a weldable (joinable) metal such as stainless steel, aluminum, aluminum alloy, iron, or plated steel sheet, or resin.

[0030] With this configuration, the container 100 has a pair of long sides 101 on both sides in the Y-axis direction, a pair of short sides 102 on both sides in the X-axis direction, and a bottom surface 103 on the underside in the negative Z-axis direction. The short sides 102 are rectangular flat portions that form the short sides of the container 100. The short sides 102 are adjacent to the long sides 101 and the bottom surface 103 and have a smaller area than the long sides 101. The long sides 101 are rectangular flat portions that form the long sides of the container 100. The long sides 101 are adjacent to the short sides 102 and the bottom surface 103 and have a larger area than the short sides 102. The bottom surface 103 is a rectangular flat portion that forms the bottom of the container 100 and is arranged adjacent to the long sides 101 and the short sides 102.

[0031] As shown in FIGS. 1 and 2 , the lid 120 is formed with a gas exhaust valve 121 and a liquid port 122. The gas exhaust valve 121 is a safety valve that releases pressure when the pressure inside the container 100 increases excessively. The liquid port 122 is an electrolyte liquid port formed in the lid 120 for injecting the electrolyte into the container 100 during the manufacture of the energy storage device 10. Specifically, the liquid port 122 is a circular through-hole that penetrates the lid 120 in the Z-axis direction. In this embodiment, the gas exhaust valve 121 is disposed at the center of the lid 120 in the X-axis direction and the Y-axis direction, and the liquid port 122 is disposed near the negative X-axis direction and the Y-axis direction of the lid 120. In other words, the liquid port 122 is disposed between the gas exhaust valve 121 and the electrode terminal 200 in the negative X-axis direction. The gas exhaust valve 121 and the liquid port 122 may be disposed at any position on the lid 120. The lid 120 is an example of a wall portion that the container 100 has.

[0032] The closing member 300 is a liquid filling plug that is disposed in the Z-axis direction (a second direction intersecting the first direction) of the lid 120 of the container 100 and is joined to the lid 120 to close the liquid port 122 of the lid 120. In this embodiment, the closing member 300 is a sealing component (sealing plate) that is flat and oval when viewed from the Z-axis direction and seals the liquid port 122. Specifically, after the electrolyte is poured into the container 100 through the liquid port 122 during the manufacture of the energy storage device 10, the closing member 300 is disposed in the Z-axis positive direction of the lid 120 and joined to the lid 120 by welding or the like to close the liquid port 122. As a result, as shown in FIG. 2(b), a substantially annular joint portion 400 is formed by joining (welding) the closing member 300 and the lid 120 so as to surround the periphery of the liquid port 122. The material of the closing member 300 is not particularly limited, and any metal or the like that can be used for the container 100 can be used. In particular, the closing member 300 is formed from a material that can be joined (welded) to the container 100 (lid 120), such as the same material as the container 100 (lid 120). A detailed description of the configuration of the closing member 300 will be given later.

[0033] The electrode terminals 200 are terminal members (positive and negative electrode terminals) of the energy storage element 10 that are placed on the lid 120 of the container 100. The electrode terminals 200 are electrically connected to the positive and negative electrode plates of the electrode assembly via current collectors. In other words, the electrode terminals 200 are metal members that draw out electricity stored in the electrode assembly to the external space of the energy storage element 10 and introduce electricity into the internal space of the energy storage element 10 to store electricity in the electrode assembly. The electrode terminals 200 are made of aluminum, an aluminum alloy, copper, a copper alloy, or the like.

[0034] The electrode assembly is an electricity storage element (power generating element) formed by stacking a positive electrode plate, a negative electrode plate, and a separator. The positive electrode plate is formed by forming a positive electrode active material layer on a positive electrode substrate layer, which is a current collecting foil made of a metal such as aluminum or an aluminum alloy. The negative electrode plate is formed by forming a negative electrode active material layer on a negative electrode substrate layer, which is a current collecting foil made of a metal such as copper or a copper alloy. As the active material used in the positive electrode active material layer and the negative electrode active material layer, any known material capable of absorbing and releasing lithium ions can be used. The separator can be a microporous resin sheet or nonwoven fabric. In this embodiment, the electrode assembly is formed by stacking electrode plates (positive electrode plates and negative electrode plates) in the Y-axis direction. The electrode assembly may be of any shape, such as a wound electrode assembly formed by winding electrode plates (positive electrode plates and negative electrode plates), a stacked electrode assembly formed by stacking multiple flat electrode plates, or a bellows-shaped electrode assembly in which electrode plates are folded in a bellows shape.

[0035] The current collectors are conductive members (positive electrode current collector and negative electrode current collector) that electrically connect the electrode terminal 200 and the electrode body. The current collectors are connected (joined) to the electrode terminal 200 and the electrode body by crimping, welding, or the like. The positive electrode current collector is formed of aluminum or an aluminum alloy, like the positive electrode substrate layer of the positive electrode plate, and the negative electrode current collector is formed of copper or a copper alloy, like the negative electrode substrate layer of the negative electrode plate. The upper gasket 210 is disposed between the lid 120 and the electrode terminal 200 and is a gasket that insulates and seals between the lid 120 and the electrode terminal 200. The lower gasket is disposed between the lid 120 and the current collector and is a gasket that insulates and seals between the lid 120 and the current collector. The upper gasket 210 and the lower gasket may be formed of any material that has insulating properties.

[0036] [2. Description of the Closing Member 300] Next, the configuration of the blocking member 300 will be described in detail. Fig. 3 is a top view and a cross-sectional view showing the configuration of the blocking member 300 according to this embodiment. Specifically, Fig. 3(a) is a top view showing the configuration of the blocking member 300 and its periphery shown in Fig. 2(b) when viewed from the positive direction of the Z axis, and Fig. 3(b) is a cross-sectional view showing the cross section of the configuration of Fig. 3(a) taken along a plane passing through line IIIb-IIIb and parallel to the YZ plane.

[0037] 3, the closing member 300 has a main body 301 and a pair of extension portions 302. The main body 301 is the main body of the closing member 300 and is located at the center of the closing member 300 in the Y-axis direction. The main body 301 is disposed in the positive direction of the Z-axis from the liquid port 122, abuts against the lid 120 while covering the entire liquid port 122, and is joined to the lid 120 to close the liquid port 122. In this embodiment, the main body 301 is a square plate-like portion when viewed in the Z-axis direction.

[0038] The pair of extension portions 302 are plate-like portions located at both ends of the closing member 300 in the Y-axis direction, and extend from the main body portion 301 on both sides in the Y-axis direction. The pair of extension portions 302 extend (protrude) from the main body portion 301 toward the pair of long side surfaces 101 of the container 100, and are used as portions that press and fix (temporarily fix) the closing member 300 to the lid body 120 when joining the closing member 300 to the lid body 120. In this embodiment, the pair of extension portions 302 are protrusions that protrude in a semicircular shape from the main body portion 301 on both sides in the Y-axis direction, and have the same shape (shapes that are plane-symmetrical with respect to a plane that passes through the center of the main body portion 301 and is parallel to the XZ plane). In other words, the extension portion 302 in the positive direction of the Y-axis protrudes in a semicircular shape from the positive end of the main body portion 301 in the positive direction of the Y-axis, and the extension portion 302 in the negative direction of the Y-axis protrudes in a semicircular shape from the negative end of the main body portion 301 in the negative direction of the Y-axis.

[0039] Thus, the extension portion 302 has a shape in which the width in the X-axis direction decreases with increasing distance from the main body portion 301. In other words, the extension portion 302 has a smaller width in the X-axis direction at its Y-axis direction end portion than the main body portion 301. For this reason, the length in the X-axis direction (first direction) of the end portion in the Y-axis direction (third direction intersecting the first direction and the second direction) of the blocking member 300 is shorter than the length in the X-axis direction (first direction) of the center portion in the Y-axis direction (third direction).

[0040] Furthermore, because the extension portions 302 protrude from both ends of the square-shaped main body 301 in the Y-axis direction, the length of the closing member 300 in the Y-axis direction (third direction) is longer than the length of the closing member 300 in the X-axis direction (first direction). Because the liquid port 122 is circular, the distance between the liquid port 122 and the Y-axis direction (third direction) edge on both sides of the Y-axis direction (third direction) of the closing member 300 is greater than the distance between the liquid port 122 and the X-axis direction (first direction) edge on at least one side of the X-axis direction (first direction). In this embodiment, the distance between the liquid port 122 and the Y-axis direction (third direction) edge on both sides of the Y-axis direction (third direction) of the closing member 300 is greater than the distance between the liquid port 122 and the X-axis direction (first direction) edge on both sides of the X-axis direction (first direction) of the closing member 300.

[0041] 3(a), for a portion of the closure member 300 in the positive Y-axis direction, the distance between the edge of the closure member 300 in the Y-axis direction and the liquid port 122 (the amount of protrusion in the Y-axis direction from the liquid port 122) is defined as a first distance A1. The first distance A1 is, for example, the distance between position P1, where a line passing through the center of the liquid port 122 and parallel to the Y-axis direction intersects with the edge of the extension portion 302 in the positive Y-axis direction, and position P2, where a line passing through the center of the liquid port 122 and parallel to the Y-axis direction intersects with the edge of the liquid port 122 in the positive Y-axis direction. The first distance A2 for the portion of the closure member 300 in the negative Y-axis direction can be defined in a similar manner.

[0042] Similarly, for the portion of the closing member 300 in the positive X-axis direction, the distance between the edge of the closing member 300 in the X-axis direction and the liquid port 122 (the amount of protrusion in the X-axis direction from the liquid port 122) is defined as a second distance B1. The second distance B1 is, for example, the distance between position Q1 of the intersection between a line passing through the center of the liquid port 122 and parallel to the X-axis direction and the edge of the main body portion 301 in the positive X-axis direction, and position Q2 of the intersection between a line passing through the center of the liquid port 122 and parallel to the X-axis direction and the edge of the liquid port 122 in the positive X-axis direction. The second distance B2 for the portion of the closing member 300 in the negative X-axis direction can be defined in a similar manner.

[0043] In the above definition, the blocking member 300 has first distances A1 and A2 on both sides in the Y-axis direction that are greater than at least one of second distances B1 and B2 on at least one side in the X-axis direction. In this embodiment, the blocking member 300 has both first distances A1 and A2 on both sides in the Y-axis direction that are greater than both second distances B1 and B2 on both sides in the X-axis direction.

[0044] The closing member 300 is joined to the lid 120 (wall portion) at a position closer to the liquid orifice 122 than the center position in the Y-axis direction (third direction) between the liquid orifice 122 and its edge in the Y-axis direction (third direction). That is, the closing member 300 is joined to the lid 120 at a position closer to the liquid orifice 122 than the center position in the Y-axis direction in a portion protruding from the liquid orifice 122 in the Y-axis direction. For example, the closing member 300 is joined to the lid 120 at a position closer to the liquid orifice 122 in the positive Y-axis direction than the center position P3 in the Y-axis direction between the position P1 of the edge in the Y-axis direction and the position P2 of the edge of the liquid orifice 122. That is, the closing member 300 is joined to the lid 120 between the position P2 and the center position P3 between the positions P1 and P2. The same applies to the portion of the closing member 300 in the negative Y-axis direction. In this embodiment, the main body 301 of the closing member 300 is joined to the lid 120.

[0045] Specifically, the closing member 300 is placed on the lid 120 in a state in which it is in contact with the lid 120. Then, the main body 301 of the closing member 300 is joined to the lid 120. For example, a laser beam is irradiated from the positive direction of the Z axis toward a position of the main body 301 that surrounds the periphery of the liquid port 122, and the main body 301 and the lid 120 are laser welded (through-hole welded). As a result, a joint 400 that is a substantially annular weld when viewed from the Z axis direction is formed in the main body 301 and the lid 120 so as to surround the periphery of the liquid port 122. The joint 400 is a fused portion formed by melting the main body 301 of the closing member 300 and the lid 120 by laser welding. Note that the joint 400 may be a portion joined by a method other than laser welding, such as resistance welding or ultrasonic welding. In this embodiment, since the blocking member 300 is longer in the Y-axis direction than in the X-axis direction, the joint 400 has an elliptical ring shape that is slightly longer in the Y-axis direction than in the X-axis direction, but it may have a circular ring shape that is the same length in the X-axis direction and in the Y-axis direction, or may have some other ring shape. The joint 400 may not be ring-shaped, but may be formed discretely.

[0046] The closing member 300 does not have an axis that is inserted into the liquid port 122 and fitted (press-fitted) into the liquid port 122. In other words, the closing member 300 is arranged in the positive direction of the Z axis of the lid body 120 (wall portion) without being fitted into the lid body 120 (wall portion), and is joined to the lid body 120 (wall portion) to close the liquid port 122.

[0047] [3 Explanation of effects] As described above, the energy storage device 10 according to the embodiment of the present invention includes the closing member 300 that is joined to the lid 120 (wall portion) of the container 100 extending in the X-axis direction (first direction) without being fitted with the lid 120. The distance between the edge of the closing member 300 and the liquid port 122 on both sides in the Y-axis direction (third direction) is greater than the distance between the edge of the closing member 300 and the liquid port 122 on at least one side in the X-axis direction. By joining the closing member 300 to the lid 120 without being fitted with the lid 120, deformation of the lid 120 and the closing member 300 during joining of the closing member 300 to the lid 120 can be suppressed, thereby suppressing poor joining. Furthermore, because the electrode terminal 200, the gas release valve 121, etc. are arranged between the closing member 300 and the short side (the side on the short side surface 102 side) of the lid 120, it is difficult to access the closing member 300 from the short side of the lid 120. For this reason, when joining the closing member 300 to the lid 120, it is difficult to fix (temporarily fix) the closing member 300 to the lid 120 from the short side of the lid 120. In contrast, the closing member 300 is easily accessible from the long side (the side on the long side surface 101 side) of the lid 120, and the closing member 300 can be easily fixed (temporarily fixed) to the lid 120 from the long side of the lid 120. For this reason, the closing member 300 is arranged so that the distance between the edge and the liquid port 122 on both sides in the Y-axis direction (the long side of the lid 120) is greater than the distance between the edge and the liquid port 122 on at least one side in the X-axis direction (the short side of the lid 120). This makes it easy to access the closing member 300 from both long side of the lid 120, and the closing member 300 can be temporarily fixed to the lid 120 from both long side of the lid 120. Therefore, when joining the closing member 300 to the lid 120, the closing member 300 can be easily and stably temporarily fixed to the lid 120. There is no need to temporarily fix the closing member 300 to the lid 120 by temporary welding or the like. Therefore, the closing member 300 can be easily and stably temporarily fixed to the lid 120 while suppressing the occurrence of poor joining when joining the closing member 300 to the lid 120, so the closing member 300 can be easily joined to the container 100.

[0048] If the closing member 300 disposed on the lid 120 of the container 100 is too large, it may cause defects, and therefore, from the viewpoint of parts costs, a smaller size is preferable. Furthermore, since the distance between the edge of the closing member 300 and the liquid port 122 in the Y-axis direction is sufficient for temporarily fixing the closing member 300 to the lid 120, the distance between the edge and the liquid port 122 on both sides in the X-axis direction can be made smaller. For this reason, the closing member 300 is formed so that the distance between the edge and the liquid port 122 on both sides in the Y-axis direction is greater than the distance between the edge and the liquid port 122 on both sides in the X-axis direction. This prevents the closing member 300 from becoming too large and causing defects, and allows the closing member 300 to be easily and stably temporarily fixed to the lid 120 from both sides in the Y-axis direction of the lid 120.

[0049] By making the length of the closing member 300 in the Y-axis direction longer than the length in the X-axis direction, it is possible to easily realize a configuration in which the distance between the edge in the Y-axis direction and the liquid port 122 is greater than the distance between the edge in the X-axis direction and the liquid port 122. This allows the closing member 300 to be easily and stably temporarily fixed to the lid 120, making it possible to easily join the closing member 300 to the container 100.

[0050] If the closing member 300 disposed on the lid 120 of the container 100 is too large, it may cause defects. Therefore, from the viewpoint of parts cost, a smaller size is preferable. Furthermore, the Y-axis end portion of the closing member 300 only needs to be large enough to temporarily fix the closing member 300 to the lid 120, so the length (width) in the X-axis direction can be shorter than that of the central portion of the closing member 300 in the Y-axis direction. Therefore, the closing member 300 is formed so that the length (width) in the X-axis direction of the Y-axis end portion is shorter than the length (width) of the X-axis direction of the central portion of the closing member 300 in the Y-axis direction. This prevents the closing member 300 from becoming too large and causing defects, while allowing the closing member 300 to be easily and stably temporarily fixed to the lid 120 from both sides in the Y-axis direction. Furthermore, by making the Y-axis end portion of the closing member 300 shorter in width than the central portion, it can also serve as a marker for the portion of the closing member 300 to be temporarily fixed.

[0051] By joining the closing member 300 to the lid 120 at a position closer to the liquid port 122 than the center position in the Y-axis direction between the edge in the Y-axis direction and the liquid port 122, it is possible to widen the end of the closing member 300 for temporarily fixing the closing member 300 to the lid 120 during joining. This allows the closing member 300 to be easily and stably temporarily fixed to the lid 120, making it possible to easily join the closing member 300 to the container 100.

[0052] [4 Explanation of Variations] (Variation 1) Next, a first modification of the above embodiment will be described. Figures 4A to 4C are top views showing the configurations of closing members 310 to 330 according to the first modification of the present embodiment. Specifically, Figures 4A to 4C correspond to (a) of Figure 3.

[0053] 4A to 4C, in this modification, blocking members 310 to 330 are arranged instead of blocking member 300 in the above embodiment. The other configurations of this modification are the same as those of the above embodiment, and therefore detailed description thereof will be omitted.

[0054] 4A, like the closing member 300 in the above embodiment, the closing member 310 has a main body portion 311 that is joined to the lid 120 and closes the liquid port 122, and a pair of extension portions 312 that extend from the main body portion 311 on both sides in the Y-axis direction. The main body portion 311 and the pair of extension portions 312 have a smaller width in the X-axis direction than the main body portion 301 and the pair of extension portions 302 in the above embodiment. Specifically, the closing member 310 has an elliptical shape when viewed in the Z-axis direction.

[0055] 4B, like the closing member 300 in the above embodiment, the closing member 320 has a main body portion 321 that is joined to the lid 120 and closes the liquid port 122, and a pair of extension portions 322 that extend from the main body portion 321 on both sides in the Y-axis direction. The main body portion 321 has a substantially circular shape (more specifically, an elliptical shape that is slightly longer in the Y-axis direction than in the X-axis direction) when viewed in the Z-axis direction. The extension portions 322 have a rectangular shape (a square or rectangular shape) that is narrower in the X-axis direction than the central portion of the main body portion 321 in the Y-axis direction when viewed in the Z-axis direction. Note that the main body portion 321 may have a circular shape, an elliptical shape that is slightly shorter in the Y-axis direction than in the X-axis direction, an oval shape, a rectangular shape, or the like when viewed in the Z-axis direction.

[0056] 4C , like the closing member 300 in the above embodiment, the closing member 330 has a main body portion 331 that is joined to the lid body 120 and closes the liquid port 122, and a pair of extension portions 332 that extend on both sides in the Y-axis direction from the main body portion 331. Specifically, the closing member 330 has a rectangular shape (oblong shape) when viewed in the Z-axis direction.

[0057] As a result, the closing members 310-330 have a length in the Y-axis direction longer than a length in the X-axis direction, similar to the closing member 300 in the above embodiment. That is, the distance between the Y-axis edge and the liquid port 122 on both sides of the closing members 310-330 is greater than the distance between the X-axis edge and the liquid port 122 on both sides of the X-axis direction. The closing members 310-330 are joined to the lid 120 at positions closer to the liquid port 122 than the center position in the Y-axis direction between the Y-axis edge and the liquid port 122. The closing members 310-330 are arranged in the positive direction of the Z-axis of the lid 120 without being fitted with the lid 120, and are joined to the lid 120 to close the liquid port 122. The length of the Y-axis end of the closing members 310, 320 in the X-axis direction is shorter than the length of the Y-axis center of the Y-axis direction.

[0058] As described above, the energy storage device according to this modification can achieve the same effects as the above-described embodiment. As in this modification, the blocking member can have various shapes when viewed in the Z-axis direction.

[0059] (Variation 2) Next, a second modification of the above embodiment will be described. Fig. 5 is a cross-sectional view showing the configuration of a blocking member 340 according to the second modification of the present embodiment. Specifically, Fig. 5 is a view corresponding to (b) of Fig. 3.

[0060] 5, in this modification, a blocking member 340 is provided instead of the blocking member 300 in the above embodiment. The blocking member 340 has the main body portion 301 and a pair of extension portions 302 that the blocking member 300 in the above embodiment has, but the main body portion 301 is provided with a shaft portion 341 and a recessed portion 342. The other configuration of this modification is the same as that of the above embodiment, so detailed description will be omitted.

[0061] The stem 341 is a protruding portion that is disposed to protrude from the main body 301 and is inserted into the liquid port 122 of the lid 120. The stem 341 is a cylindrical portion that is disposed at the center of the main body 301 when viewed from the Z-axis direction and extends from the center in the negative Z-axis direction. When viewed from the Z-axis direction, the stem 341 has an outer circumferential shape (outer diameter) that is smaller than the inner circumferential shape (inner diameter) of the liquid port 122, and is inserted into the liquid port 122 without being fitted (press-fitted). The stem 341 may be a columnar portion other than a cylindrical shape, or may have a tapered shape that gradually narrows toward the tip.

[0062] Recess 342 is disposed at the center of the outer surface (surface facing the positive Z-axis direction) of main body 301, and is a generally conical recess recessed in the negative Z-axis direction. Recess 342 is disposed in the positive Z-axis direction of shaft 341, i.e., in the positive Z-axis direction of liquid port 122. The shape of recess 342 is not particularly limited.

[0063] As described above, the energy storage device according to this modification can achieve the same effects as the above-described embodiment. In particular, in this modification, the closure member 340 has the shaft 341 that is inserted into the liquid port 122 without being fitted thereto. This allows the closure member 340 to be easily positioned relative to the closure member 120 without the closure member 340 being deformed by the fitting. Furthermore, the recess 342 can also be used as a marker when joining the closure member 340 to the closure member 120. That is, the recess 342 allows the position of the closure member 340 to be grasped, allowing the closure member 340 to be positioned accurately on the closure member 120 and joined to the closure member 120. As a result, when joining the closure member 340 to the closure member 120, the closure member 340 can be easily positioned on the closure member 120, and therefore the closure member 340 can be easily joined to the container 100.

[0064] (Variation 3) Next, a third modification of the above embodiment will be described. Fig. 6 is a cross-sectional view showing the configuration of a blocking member 350 according to the third modification of the present embodiment. Specifically, Fig. 6 is a view corresponding to (b) of Fig. 3.

[0065] 6, in this modification, a blocking member 350 is provided instead of the blocking member 300 in the above embodiment. The blocking member 350 has the main body portion 301 and a pair of extension portions 302 that the blocking member 300 in the above embodiment has, but the main body portion 301 is provided with a recess 351. The other configuration of this modification is the same as that of the above embodiment, so detailed description will be omitted.

[0066] The recess 351 is a circular recess as viewed from the Z-axis direction, with the surface of the body 301 facing the positive Z-axis direction recessed in a rectangular shape in the negative Z-axis direction, and is disposed at a position corresponding to the joint 400. That is, the body 301 and the lid 120 are joined at the recess 351. For example, a laser beam is irradiated from the positive Z-axis direction toward the recess 351, and the body 301 and the lid 120 are laser welded (through-hole welded). As a result, the body 301 and the lid 120 are formed with the joint 400, which is a welded portion that is approximately circular as viewed from the Z-axis direction and is formed along the recess 351 so as to surround the periphery of the liquid port 122.

[0067] As described above, the energy storage device according to this modification can achieve the same effects as those of the above-described embodiment. In particular, in this modification, by forming recess 351 in main body 301, the thickness of the portion to be joined (welded) in main body 301 is reduced, making it possible to easily join (weld) main body 301 to lid 120.

[0068] (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 this embodiment. The embodiment disclosed here is illustrative in all respects, and the scope of the present invention includes all modifications within the meaning and scope of the claims.

[0069] For example, in the above embodiment, the liquid port 122 is formed in the lid 120 of the container 100, and the closing member is joined to the lid 120. However, the liquid port 122 may be formed in the container body 110 of the container 100, and the closing member may be joined to the container body 110.

[0070] In the above embodiment, the distance between the edge of the closing member in the Y-axis direction on both sides in the Y-axis direction and the liquid port 122 is greater than the distance between the edge of the closing member in the X-axis direction on both sides in the X-axis direction and the liquid port 122. However, the distance between the edge of the closing member in the Y-axis direction on both sides or either side in the Y-axis direction and the liquid port 122 may be smaller than the distance between the edge of the closing member in the X-axis direction on either side in the X-axis direction and the liquid port 122.

[0071] In the above embodiment, the length of the closing member in the Y-axis direction is longer than the length in the X-axis direction. However, the length of the closing member in the X-axis direction may be longer than the length in the Y-axis direction, as long as the distance between the Y-axis direction edge and the liquid port 122 on both sides of the Y-axis direction is greater than the distance between the X-axis direction edge and the liquid port 122 on at least one side of the X-axis direction. When the liquid port 122 has a shape that is elongated in the X-axis direction, it is conceivable that the closing member will also have a shape that is elongated in the X-axis direction.

[0072] In the above embodiment, the closing member is joined to the lid 120 at a position closer to the liquid port 122 than the center position in the Y-axis direction between the edge in the Y-axis direction and the liquid port 122. However, the closing member may be joined to the lid 120 at a position farther from the liquid port 122 than the center position in the Y-axis direction. In other words, the joining portion 400 may be formed not on the main body portion of the closing member but on the extension portion.

[0073] In the above embodiment, the pair of extensions of the blocking member have the same shape (plane-symmetrical shapes), but they may have different shapes. That is, the blocking member may have an asymmetrical shape in the X-axis direction or the Y-axis direction, or a rotationally asymmetrical shape.

[0074] Any combination of the components included in the above-described embodiments and their modifications is also included within the scope of the present invention.

[0075] The present invention can be realized not only as such an electricity storage element, but also as a combination of a container and a closing member. [Industrial Applicability]

[0076] The present invention can be applied to an energy storage device such as a lithium ion secondary battery. [Explanation of symbols]

[0077] 10. Energy storage element 100 containers 101 Long side 102 short side 103 bottom 110 Container body 120 Lid 121 Gas exhaust valve 122 liquid mouth 200 electrode terminal 210 Upper gasket 300, 310, 320, 330, 340, 350 Closure member 301, 311, 321, 331 Main body 302, 312, 322, 332 extension part 341 Shaft 342, 351 recess 400 Joint

Claims

1. a container having a wall portion extending in a first direction and having a liquid port for an electrolyte; a closing member that is disposed in a second direction intersecting the first direction of the wall portion without being fitted with the wall portion and is joined to the wall portion to close the liquid port, the closing member has a distance between an edge in the third direction and the liquid orifice on both sides of the third direction intersecting with the first direction and the second direction greater than a distance between an edge in the first direction and the liquid orifice on at least one side of the first direction, The length of the blocking member in the third direction is longer than the length of the blocking member in the first direction. Energy storage element.

2. The closing member has a distance between an edge in the third direction and the liquid orifice on both sides in the third direction that is greater than a distance between an edge in the first direction and the liquid orifice on both sides in the first direction. The energy storage element according to claim 1 .

3. The length in the first direction of the end portion in the third direction of the blocking member is shorter than the length in the first direction of the central portion in the third direction. The energy storage element according to claim 1 or 2.

4. The closing member is joined to the wall portion at a position closer to the liquid orifice than a center position in the third direction between the edge in the third direction and the liquid orifice. The energy storage element according to any one of claims 1 to 3.

5. The closing member has a shaft portion that is inserted into the liquid port without being fitted thereto. The energy storage element according to any one of claims 1 to 4.

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