JP7739726B2 - Energy storage element - Google Patents

Description

The present invention relates to an energy storage device comprising a container and a closing member that closes the liquid port of the container.

Conventionally, energy storage elements have been known that include a container with an electrolyte inlet and a blocking member that closes the inlet. For example, Patent Document 1 discloses a sealed battery (energy storage element) that includes a battery case (container) with a liquid inlet (liquid inlet) and a sealing plug (blocking member) that seals the liquid inlet.

JP 2018-45888 A

In energy storage elements with the above-mentioned conventional configurations, joining the closure member to the container may be difficult. 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. In other words, in the energy storage element disclosed in Patent Document 1, the closure member is fixed to the container by fitting (press-fitting) it into the liquid inlet, and the closure member is joined to the container in this state. However, in this case, the container or the closure member may deform when fitting (press-fitting) the closure member into the liquid inlet, which may result in poor joining when joining the closure member to the container and make joining difficult.

The present invention was made by the inventors by focusing on the above-mentioned problem, and aims to provide an energy storage element in which a closure member can be easily joined to a container.

To achieve the above object, one aspect of the present invention provides an energy storage device comprising: a container having a wall portion extending in a first direction and having an electrolyte inlet formed therein; and a closure member disposed in a second direction intersecting the first direction of the wall portion without being fitted with the wall portion and joined to the wall portion to close the inlet, wherein the distance between the edge of the closure member in the third direction and the inlet on both sides of a third direction intersecting the first and second directions is greater than the distance between the edge of the first direction and the inlet on at least one side of the first direction.

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 when joining the closure member to the wall portion can be suppressed, thereby reducing poor joining. Furthermore, because an electrode terminal or gas exhaust valve, etc., is located 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, making it 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 the closure member can be easily fixed (temporarily fixed) to the wall portion from the long side of the wall portion. For this reason, the closure member is positioned so that the distance between the edge and the liquid orifice on both sides in the third direction (the long side 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 of the wall portion). This allows the closure 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, making it easy and stable to temporarily fix the closure member to the wall portion when joining the closure member to the wall portion. Therefore, the closure member can be easily and stably temporarily fixed to the wall portion while preventing poor joining when joining the closure member to the wall portion, making it easy to join the closure member to the container.

The closing 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.

If the closure member placed on the wall of the container is too large, it may cause problems, and from the perspective of parts costs, a smaller size is preferable. Furthermore, since the distance between the edge and the liquid orifice 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 orifice on both sides in the first direction can be made smaller. Therefore, the closure member is formed so that the distance between the edge and the liquid orifice on both sides in the third direction is greater than the distance between the edge and the liquid orifice on both sides in the first direction. This prevents the closure member from becoming too large and causing problems, while also allowing the closure member to be easily and stably temporarily fixed to the wall from both sides in the third direction.

The length of the blocking member in the third direction may be longer than its length in the first direction.

By making the length of the closure member longer in the third direction than in the first direction, it is possible to easily achieve 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 allows the closure member to be easily and stably temporarily fixed to the wall portion, making it easy to join the closure member to the container.

The length of the blocking member in the first direction at the end in the third direction may be shorter than the length of the center in the third direction at the first direction.

If the closure member placed on the wall of the container is too large, it may cause problems, and from the perspective of parts costs, a smaller size is preferable. Furthermore, the end of the closure member in the third direction only needs to be large enough to temporarily fix the closure member to the wall, so the length in the first direction can be shorter than the center of the closure member in the third direction. Therefore, the closure member is formed so that the length in the first direction of the end of the third direction is shorter than the length in the first direction of the center of the third direction. This prevents the closure member from becoming too large and causing problems, while also allowing the closure member to be easily and stably temporarily fixed to the wall from both sides of the wall in the third direction.

The blocking member may be joined to the wall portion at a position closer to the liquid port than the center position in the third direction between the edge in the third direction and the liquid port.

By joining the closure member to the wall 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, the end of the closure member can be made wider for temporarily fixing the closure member to the wall when joining. This allows the closure member to be easily and stably temporarily fixed to the wall, making it easier to join the closure member to the container.

The closure member may have a shaft portion that is inserted into the liquid port without being fitted into it.

By having a shaft through which the closure member is inserted without being fitted into the liquid port, the wall and closure member do not deform due to fitting, and the closure member can be easily positioned relative to the wall. This allows the closure member to be easily positioned on the wall when joining the closure member to the wall, making it easy to join the closure member to the container.

The present invention can be realized not only as such an energy storage element, but also as a combination of a container and a closing member.

The energy storage element of the present invention allows the closure member to be easily joined to the container.

1 is a perspective view showing the appearance of an energy storage element according to an embodiment; 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. 3A and 3B are a top view and a cross-sectional view showing the configuration of a closing member according to an embodiment. FIG. 10 is a top view showing the configuration of a blocking member according to a first modified example of the embodiment. FIG. 10 is a top view showing the configuration of a blocking member according to a first modified example of the embodiment. FIG. 10 is a top view showing the configuration of a blocking member according to a first modified example of the embodiment. FIG. 10 is a cross-sectional view showing the configuration of a blocking member according to a second modified example of the embodiment. FIG. 11 is a cross-sectional view showing the configuration of a blocking member according to a third modified example of the embodiment.

Hereinafter, with reference to the drawings, an energy storage element according to an embodiment of the present invention (including its variations) will be described. Note that the embodiments described below are all 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 figure, dimensions and the like are not strictly depicted. In each figure, the same or similar components are designated by the same reference numerals.

In the following description and drawings, the direction in which a pair of electrode terminals (positive and negative, hereinafter the same) of the energy storage element are aligned, or the direction in which the short sides of the container face each other, is defined as the X-axis direction. The direction in which the long sides of the container face each other, or the thickness direction of the container, is defined as the Y-axis direction. The direction in which the container body and lid of the container are aligned, the direction in which the lid and closing member are aligned, or the up-down direction, is defined as the Z-axis direction. The X-axis, Y-axis, and Z-axis directions intersect each other (orthogonal in this embodiment). Note that depending on the usage mode, the Z-axis may not be the up-down direction; however, for ease of explanation, the following description will be based on the Z-axis being the up-down direction.

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. Below, 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 perpendicular, may also include cases where the directions or orientations are not strictly those of the same kind. For example, when two directions are parallel, it does not only mean that the two directions are completely parallel, but also means that they are substantially parallel, i.e., there is a difference of, for example, a few percent. Furthermore, in the following description, when the term "insulation" is used, it means "electrical insulation."

(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 using 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 a container 100. Specifically, Figure 2(a) shows the state before bonding the closing member 300 to the container 100, and Figure 2(b) shows the state after bonding the closing member 300 to the container 100.

The energy storage element 10 is a secondary battery (single cell) capable of charging and discharging electricity, specifically a non-aqueous electrolyte secondary battery such as a lithium-ion secondary battery. The energy storage element 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, boat, snowmobile, agricultural machinery, construction machinery, or electric railway vehicle. Examples of such automobiles include electric vehicles (EVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and gasoline-powered automobiles. Examples of such electric railway vehicles include electric trains, monorails, linear motor cars, and hybrid electric trains equipped with both a diesel engine and an electric motor. The energy storage element 10 can also be used as a stationary battery for home use or as a power generator.

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 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, or a polygonal prism shape other than a rectangular parallelepiped, etc.

As shown in FIG. 1, the energy storage element 10 comprises 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, and an electrolyte (non-aqueous electrolyte), but these are not shown in the figure. There are no particular restrictions on the type of electrolyte, and various types can be selected as long as they do not impair the performance of the energy storage element 10.

In addition to the above components, the energy storage element 10 may also include spacers arranged to the sides or below the electrode assembly, and an insulating film that encases the electrode assembly. 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. 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.

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 has an opening 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 extending in the X axis direction (first direction) from the positive Z axis direction of the container body 110. The container 100 is structured 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 (container body 110 and lid 120) is not particularly limited, but can be a weldable (joinable) metal such as stainless steel, aluminum, aluminum alloy, iron, or plated steel sheet, or resin.

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 located adjacent to the long sides 101 and the short sides 102.

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 inside the container 100 if the pressure rises excessively. The liquid port 122 is an electrolyte liquid port formed in the lid 120 for injecting 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 located at the center of the lid 120 in the X-axis direction and the Y-axis direction, and the liquid port 122 is located near the negative X-axis direction and the center of the lid 120 in the Y-axis direction. In other words, the liquid port 122 is located 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 located anywhere on the lid 120. The lid 120 is an example of a wall portion of the container 100.

The blocking member 300 is a liquid filling plug that is positioned 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 blocking member 300 is a flat, oval-shaped sealing component (sealing plate) that seals the liquid port 122. Specifically, after electrolyte is poured into the container 100 through the liquid port 122 during the manufacture of the energy storage device 10, the blocking member 300 is positioned in the positive Z-axis 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 400 is formed by joining (welding) the blocking member 300 and the lid 120 to surround the liquid port 122. The material of the closing member 300 is not particularly limited, but any metal that can be used for the container 100 can be used. In particular, the closing member 300 is made of 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 provided below.

The electrode terminals 200 are terminal members (positive and negative 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 conduct 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.

The electrode assembly is an electricity storage element (power generating element) formed by stacking positive and negative electrode plates 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 collector 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 collector foil made of a metal such as copper or a copper alloy. The active materials used in the positive and negative electrode active material layers can be any known material capable of absorbing and releasing lithium ions. The separator can be a microporous resin sheet or nonwoven fabric. In this embodiment, the electrode assembly is formed by stacking electrode plates (positive 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 and negative electrode plates), a stacked electrode assembly formed by stacking multiple flat electrode plates, or a bellows-shaped electrode assembly formed by folding electrode plates in an accordion-like shape.

The current collectors are conductive members (positive and negative current collectors) 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 other methods. The positive current collector is made of aluminum or an aluminum alloy, similar to the positive electrode substrate layer of the positive electrode plate, and the negative current collector is made of copper or a copper alloy, similar to 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 provides insulation and sealing between the lid 120 and the electrode terminal 200. The lower gasket is disposed between the lid 120 and the current collector and provides insulation and sealing between the lid 120 and the current collector. The upper gasket 210 and the lower gasket may be made of any insulating material.

[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. 3A is a top view showing the configuration of the blocking member 300 and its periphery shown in Fig. 2B when viewed from the positive direction of the Z axis, and Fig. 3B is a cross-sectional view showing the cross section of the configuration of Fig. 3A taken along a plane passing through line IIIb-IIIb and parallel to the YZ plane.

As shown in FIG. 3, the closure member 300 has a main body portion 301 and a pair of extension portions 302. The main body portion 301 is the main body portion of the closure member 300 located at the center of the closure member 300 in the Y-axis direction. The main body portion 301 is positioned in the positive Z-axis direction of the liquid port 122, abuts against the lid body 120 while covering the entire liquid port 122, and is joined to the lid body 120 to close the liquid port 122. In this embodiment, the main body portion 301 is a square plate-shaped portion when viewed in the Z-axis direction.

The pair of extensions 302 are plate-shaped portions located at both ends of the closure member 300 in the Y-axis direction, and extend from the main body 301 on both sides in the Y-axis direction. The pair of extensions 302 extend (protrude) from the main body 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 closure member 300 to the lid 120 when joining the closure member 300 to the lid 120. In this embodiment, the pair of extensions 302 are semicircular protrusions that protrude from the main body 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 301 and is parallel to the XZ plane). In other words, the extension portion 302 in the positive Y-axis direction protrudes in a semicircular shape from the end of the main body 301 in the positive Y-axis direction, and the extension portion 302 in the negative Y-axis direction protrudes in a semicircular shape from the end of the main body 301 in the negative Y-axis direction.

As such, the extension portion 302 has a shape in which its width in the X-axis direction decreases the further it is from the main body portion 301. In other words, the Y-axis end of the extension portion 302 has a smaller width in the X-axis direction than the main body portion 301. As a result, the length of the blocking member 300 in the X-axis direction (first direction) at the end in the Y-axis direction (third direction intersecting the first and second directions) is shorter than the length of the X-axis direction (first direction) at the center in the Y-axis direction (third direction).

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

For example, as shown in FIG. 3(a), for the 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 the 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.

Similarly, for the portion of the closure member 300 in the positive X-axis direction, the distance between the edge of the closure 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 the second distance B1. The second distance B1 is, for example, the distance between position Q1, where a line passing through the center of the liquid port 122 and parallel to the X-axis direction intersects with the edge of the main body portion 301 in the positive X-axis direction, and position Q2, where a line passing through the center of the liquid port 122 and parallel to the X-axis direction intersects with the edge of the liquid port 122 in the positive X-axis direction. The second distance B2 for the portion of the closure member 300 in the negative X-axis direction can be defined in a similar manner.

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

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

Specifically, the closure member 300 is placed on the lid 120 while abutting against the lid 120. The main body 301 of the closure member 300 is then joined to the lid 120. For example, a laser beam is irradiated from the positive Z-axis direction toward a position on the main body 301 that surrounds 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, which is a substantially annular weld when viewed from the Z-axis direction, is formed in the main body 301 and the lid 120, surrounding the liquid port 122. The joint 400 is a fused portion formed by laser welding the main body 301 of the closure member 300 and the lid 120. Note that the joint 400 may be formed by a method other than laser welding, such as resistance welding or ultrasonic welding. In this embodiment, because 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 also have a circular ring shape with the same length in the X-axis and Y-axis directions, or some other ring shape. The joint 400 may also be formed discretely rather than in a ring shape.

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

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

If the closure member 300 placed on the lid 120 of the container 100 is too large, it may cause problems, and from the perspective of parts cost, a smaller size is preferable. Furthermore, since the distance between the edge of the closure member 300 and the liquid port 122 in the Y-axis direction is sufficient to temporarily secure it 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. Therefore, the closure 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 closure member 300 from becoming too large and causing problems, while also allowing the closure member 300 to be easily and stably temporarily secured to the lid 120 from both sides in the Y-axis direction.

By making the length of the closure member 300 longer in the Y-axis direction than in the X-axis direction, it is easy to achieve 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 closure member 300 to be easily and stably temporarily fixed to the lid 120, making it easy to join the closure member 300 to the container 100.

If the closure member 300 placed on the lid 120 of the container 100 is too large, it may cause problems, and therefore a smaller size is preferable from the perspective of parts costs. Furthermore, the Y-axis end of the closure member 300 only needs to be large enough to temporarily secure the closure member 300 to the lid 120, so the length (width) in the X-axis direction can be shorter than the center of the closure member 300 in the Y-axis direction. Therefore, the closure member 300 is formed so that the length (width) in the X-axis direction of the Y-axis end is shorter than the length (width) in the X-axis direction of the center of the Y-axis direction. This prevents the closure member 300 from becoming too large and causing problems, while also allowing the closure member 300 to be easily and stably temporarily secured to the lid 120 from both sides in the Y-axis direction. Furthermore, making the Y-axis end of the closure member 300 shorter in width than the center can also serve as a marker for the portion of the closure member 300 to be temporarily secured.

By joining the closure 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, the end of the closure member 300 can be made wider for temporarily fixing the closure member 300 to the lid 120 during joining. This allows the closure member 300 to be easily and stably temporarily fixed to the lid 120, making it easy to join the closure member 300 to the container 100.

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

As shown in Figures 4A to 4C, in this modified example, blocking members 310 to 330 are used instead of blocking member 300 in the above embodiment. The remaining configuration of this modified example is the same as in the above embodiment, so detailed description will be omitted.

As shown in FIG. 4A , the blocking member 310, like the blocking member 300 in the above embodiment, has a main body portion 311 that is joined to the lid body 120 and blocks 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 blocking member 310 has an elliptical shape when viewed in the Z-axis direction.

As shown in FIG. 4B , the closure member 320, like the closure member 300 in the above embodiment, has a main body portion 321 that is joined to the lid body 120 and blocks 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. When viewed in the Z-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 (square or rectangular) that is narrower in the X-axis direction than the central portion of the main body portion 321 in the Y-axis direction. Note that when viewed in the Z-axis direction, 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.

As shown in FIG. 4C , the blocking member 330, like the blocking member 300 in the above embodiment, has a main body portion 331 that is joined to the lid body 120 and blocks the liquid port 122, and a pair of extension portions 332 that extend from the main body portion 331 on both sides in the Y-axis direction. Specifically, the blocking member 330 has a rectangular shape when viewed in the Z-axis direction.

As a result, the blocking members 310-330, like the blocking member 300 in the above embodiment, have a longer length in the Y-axis direction than in the X-axis direction. In other words, the distance between the Y-axis edge and the liquid port 122 on both sides of the Y-axis direction of the blocking 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 blocking members 310-330 are 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 Y-axis edge and the liquid port 122. The blocking members 310-330 are positioned in the positive Z-axis direction of the lid 120 without being fitted with the lid 120, and are joined to the lid 120 to block the liquid port 122. The X-axis length of the Y-axis end of the blocking members 310 and 320 is shorter than the X-axis length of the Y-axis center.

As described above, the energy storage element of this modified example can achieve the same effects as the above-described embodiment. As in this modified example, the blocking member can take on various shapes when viewed in the Z-axis direction.

(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 corresponds to Fig. 3(b).

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

The shank 341 is a protruding portion that protrudes from the main body 301 and is inserted into the liquid port 122 of the lid 120. When viewed from the Z-axis direction, the shank 341 is a cylindrical portion that is located at the center of the main body 301 and extends from this center in the negative Z-axis direction. When viewed from the Z-axis direction, the shank 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 shank 341 may be a columnar portion other than a cylindrical shape, or may have a tapered shape that gradually narrows toward the tip.

The recess 342 is located at the center of the outer surface (the surface facing the positive Z-axis direction) of the main body 301, and is a generally conical recess recessed in the negative Z-axis direction. The recess 342 is located in the positive Z-axis direction of the shaft 341, i.e., in the positive Z-axis direction of the liquid port 122. There are no particular limitations on the shape of the recess 342.

As described above, the energy storage element according to this modified example can achieve the same effects as the above-described embodiment. In particular, in this modified example, the closure member 340 has an axis 341 that is inserted without being fitted into the liquid port 122. 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. The recess 342 can also be used as a marker when joining the closure member 340 to the closure member 120. In other words, the recess 342 allows the position of the closure member 340 to be determined, allowing the closure member 340 to be positioned accurately on the closure member 120 and joined to the closure member 120. As a result, the closure member 340 can be easily positioned on the closure member 120 when joining the closure member 340 to the closure member 120, thereby making it easy to join the closure member 340 to the container 100.

(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 corresponds to Fig. 3(b).

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

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 recessed in the negative Z-axis direction in a rectangular shape, and is located at a position corresponding to the joint 400. In other words, the body 301 and the lid 120 are joined at the recess 351. For example, laser light is irradiated toward the recess 351 from the positive Z-axis direction, 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 weld that is approximately circular as viewed from the Z-axis direction and is formed along the recess 351 to surround the liquid port 122.

As described above, the energy storage element according to this modified example can achieve the same effects as the above-described embodiment. In particular, in this modified example, by forming a recess 351 in the main body 301, the thickness of the portion of the main body 301 to be joined (welded) is reduced, making it easier to join (weld) the main body 301 to the lid 120.

(Other Modifications)
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 an example in all respects, and the scope of the present invention includes all modifications within the meaning and scope equivalent to the claims.

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

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

In the above embodiment, the length of the blocking member in the Y-axis direction is longer than the length in the X-axis direction. However, the length of the blocking 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 edge and the liquid port 122 on both sides of the Y-axis direction is greater than the distance between the X-axis edge and the liquid port 122 on at least one side of the X-axis direction. If the liquid port 122 is elongated in the X-axis direction, it is conceivable that the blocking member will also be elongated in the X-axis direction.

In the above embodiment, the closure 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 closure member may also 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 on the extension portion rather than on the main body portion of the closure member.

In the above embodiment, the pair of extension portions of the blocking member have the same shape (plane-symmetrical shapes), but they may also have different shapes. In other words, the blocking member may have an asymmetrical shape in the X-axis direction or Y-axis direction, or a rotationally asymmetrical shape.

Configurations constructed by any combination of the components included in the above embodiments and their variations are also within the scope of the present invention.

The present invention can be realized not only as such an energy storage element, but also as a combination of a container and a closing member.

The present invention can be applied to energy storage elements such as lithium-ion secondary batteries.

REFERENCE SIGNS LIST 10 Energy storage element 100 Container 101 Long side surface 102 Short side surface 103 Bottom surface 110 Container body 120 Lid 121 Gas exhaust valve 122 Liquid port 200 Electrode terminal 210 Upper gasket 300, 310, 320, 330, 340, 350 Closing member 301, 311, 321, 331 Main body portion 302, 312, 322, 332 Extension portion 341 Shaft portion 342, 351 Recess 400 Joint portion

Claims (5)

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. The energy storage element according to claim 1 , wherein the distance between the third-direction edge and the liquid port on both sides of the third direction of the blocking member is greater than the distance between the first-direction edge and the liquid port on both sides of the first direction. The energy storage device according to claim 1 or 2 , wherein 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 any one of claims 1 to 3 , wherein the blocking member is joined to the wall portion at a position closer to the liquid port than a center position in the third direction between the edge in the third direction and the liquid port. The energy storage device according to claim 1 , wherein the closing member has a shaft portion that is inserted into the liquid port without being fitted into the liquid port.