Energy storage element

Abstract

To provide a power storage element capable of improving the joining quality of a container and a closing member.SOLUTION: A power storage element 10 includes a container 100 in which a through hole 130 is formed, and a closing member 200 that is joined to the container 100 and closes the through hole 130. The container 100 and the closing member 200 are arranged so as to be overlapped in a penetrating direction of the through hole 130, and a laser welded portion 150 to which the container 100 and the closing member 200 are joined by laser welding is formed in the overlapped portion. A space (first space S1 and second space S2) extending from the laser welded portion 150 toward the through hole 130 is formed between the container 100 and the closing member 200.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to an energy storage element including a container. [Background technology]

[0002] Conventionally, there is known an energy storage element having a container, in which a through hole formed in the container is blocked with a blocking member. For example, Patent Document 1 discloses a sealed battery (energy storage element) having a through hole formed in a battery case (container) sealed with a sealing member (blocking member). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2012-248336 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the configuration in which a through hole formed in a container is blocked by a blocking member as in the above-mentioned conventional energy storage element, the blocking member may be joined to the container by laser welding, and the through hole may be blocked by the blocking member. However, the present inventors have found that in this case, pinholes may occur in the laser welded portion (melted portion) of the container and the blocking member, resulting in poor bonding, poor appearance, and reduced bonding quality. If poor bonding occurs between the container and the blocking member, it may become impossible to maintain a sealed state inside the container, the electrolyte inside the container may leak out, the poorly bonded portion may corrode, and other problems may occur.

[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 that can improve the bonding quality between a container and a closing member. [Means for solving the problem]

[0006] In order to achieve the above-mentioned object, an energy storage element according to one embodiment of the present invention comprises a container having a through hole formed therein, and a blocking member joined to the container to block the through hole, the container and the blocking member being arranged stacked in the penetration direction of the through hole, a laser welded portion is formed in the stacked portion where the container and the blocking member are joined by laser welding, and a space is formed between the container and the blocking member extending from the laser welded portion toward the through hole.

[0007] According to this, in the energy storage element, the container and the blocking member are arranged in a stacked manner in the penetration direction of the through hole of the container, a laser weld is formed in the stacked portion, and a space extending from the laser weld toward the through hole is formed between the container and the blocking member. Here, if a space extending from the laser welded portion of the container and the blocking member toward the through hole is formed during laser welding, the gas generated during laser welding escapes into the space, and the occurrence of pinholes can be suppressed. In other words, if a space extending from the laser weld toward the through hole is formed between the container and the blocking member, it can be seen that a space extending from the laser welded portion of the container and the blocking member toward the through hole is formed during laser welding. As a result, the gas generated during laser welding can escape into the space, and the occurrence of pinholes can be suppressed, so that an energy storage element with improved joining quality of the container and the blocking member can be realized.

[0008] The space may include a first space arranged adjacent to the laser weld on the through hole side of the laser weld, and a second space arranged connected to the first space on the through hole side of the first space and having a larger volume than the first space.

[0009] According to this, a first space is disposed on the through hole side of the laser welded portion, and a second space having a larger volume than the first space is disposed on the through hole side of the first space, so that gas generated at the laser welded portion escapes to the first space and then to the second space. This allows the gas generated at the laser welded portion to escape effectively, thereby improving the joining quality of the container and the closing member.

[0010] The space may be formed by recessing at least one of the container and the closing member.

[0011] According to this, the space can be easily formed by recessing at least one of the container and the closing member, which makes it possible to easily improve the bonding quality between the container and the closing member.

[0012] The blocking member may have an axial portion that is inserted into the through hole, and a gap that is connected to the space and penetrates the container is formed between the axial portion and the inner surface of the through hole.

[0013] According to this, a gap that is connected to the above-mentioned space is formed between the shaft portion of the closing member and the inner surface of the through hole of the container, so that the gas generated at the laser welded portion can escape into the container through the gap. This allows the gas generated at the laser welded portion to escape effectively, thereby improving the joining quality of the container and the closing member.

[0014] At least one of the container and the closing member may have a projection that projects toward the other and abuts against the other, the projection being disposed within the space.

[0015] According to this, by providing a protrusion on at least one of the container and the closing member that abuts against the other, the space is formed by the protrusion, and therefore the space can be easily formed, which makes it possible to easily improve the joining quality of the container and the closing member.

[0016] 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. Effect of the Invention

[0017] According to the energy storage device of the present invention, the joining quality between the container and the closing member can be improved. [Brief description of the drawings]

[0018] [Figure 1] 1 is a perspective view showing the appearance of an energy storage element according to an embodiment; [Diagram 2] FIG. 2 is an exploded perspective view showing each component of the energy storage element according to the embodiment. [Diagram 3] 5A and 5B are a perspective view and a cross-sectional view showing the configuration of the periphery of a through hole of a lid body and a closing member in the embodiment. [Figure 4] 4 is a cross-sectional view showing a structure in which a closing member is joined to a lid body in the embodiment. FIG. [Diagram 5] 10 is a cross-sectional view showing the configuration of the periphery of a through-hole of a lid and a closing member according to a first modified example of the embodiment. FIG. [Figure 6] 11 is a cross-sectional view showing the configuration of the periphery of a through-hole of a lid body and a closing member according to a second modified example of the embodiment. FIG. [Figure 7] 13A and 13B are a perspective view and a cross-sectional view showing the configuration of the periphery of a through-hole of a lid body and a closing member according to a third modification of the embodiment. [Figure 8] FIG. 11 is a cross-sectional view showing a configuration in which a closing member is joined to a lid according to a third modified example of the embodiment. [Figure 9] 13 is a cross-sectional view showing the configuration of the periphery of a through-hole of a lid body and a closing member according to a fourth modified example of the embodiment. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] 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 are all comprehensive or specific examples. The numerical values, shapes, materials, components, arrangement and connection forms of the components, manufacturing processes, and the order of the manufacturing processes shown in the following embodiments are merely examples and are not intended to limit the present invention. In each drawing, the dimensions are not strictly illustrated. In each drawing, the same or similar components are given the same reference numerals.

[0020] 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, the arrangement direction of a pair of current collectors, or the opposing direction of the short side surfaces of the container is defined as the X-axis direction. The opposing direction of the long side surfaces of the container, or the thickness direction of the container, is defined as the Y-axis direction. The arrangement direction of the container body and the lid of the container, the penetration direction of the through hole of the container (lid), or the up-down direction is defined as the Z-axis direction. These X-axis, Y-axis, and Z-axis directions intersect with each other (orthogonal in this embodiment). Note that, depending on the mode of use, the Z-axis direction may not be the up-down direction, but for convenience of explanation, the following description will be given assuming that the Z-axis direction is the up-down direction.

[0021] In the following description, for example, the positive X-axis direction indicates the direction of the X-axis arrow, and the negative X-axis direction indicates the opposite direction to the positive X-axis direction. The same applies to the Y-axis direction and the Z-axis direction. Furthermore, expressions indicating relative directions or attitudes, such as parallel and perpendicular, also include cases where the directions or attitudes are not strictly those. For example, saying that two directions are perpendicular not only means that the two directions are completely perpendicular, but also means that the directions are substantially perpendicular, that is, includes a difference of, for example, about several percent.

[0022] (Embodiment) [1 General Description of Energy Storage Element 10] First, an energy storage device 10 according to the present embodiment will be generally described with reference to Fig. 1 to Fig. 3. Fig. 1 is a perspective view showing the external appearance of the energy storage device 10 according to the present embodiment. Fig. 2 is an exploded perspective view showing the respective components of the energy storage device 10 according to the present embodiment.

[0023] 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 as a battery for driving or starting an engine of a moving body such as an automobile, a motorcycle, a watercraft, a ship, a snowmobile, an agricultural machine, a construction machine, or a railway vehicle for an electric railway. Examples of the automobile include an electric vehicle (EV), a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), and a gasoline vehicle. Examples of the railway vehicle for the electric railway include a train, a monorail, a linear motor car, and a hybrid train equipped with both a diesel engine and an electric motor. The energy storage element 10 can also be used as a stationary battery for home use or for a power generator.

[0024] 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 can use stored electricity without the user having to charge it. The energy storage element 10 may be a battery using a solid electrolyte. The energy storage element 10 may be a pouch-type energy storage element. In this embodiment, the energy storage element 10 having a flat rectangular parallelepiped (angled) shape is illustrated, but the shape of the energy storage element 10 is not limited to a rectangular parallelepiped shape, and may be a cylindrical shape, an oval cylindrical shape, a polygonal prism shape other than a rectangular parallelepiped, or the like.

[0025] As shown in FIG. 1, the energy storage element 10 includes a container 100, a blocking member 200, a pair of electrode terminals 300 (positive electrode side and negative electrode side), and a pair of upper gaskets 400 (positive electrode side and negative electrode side). As shown in FIG. 2, a pair of lower gaskets 500 (positive electrode side and negative electrode side), a pair of current collectors 600 (positive electrode side and negative electrode side), and an electrode body 700 are housed inside the container 100. Note that an electrolyte (non-aqueous electrolyte) is sealed inside the container 100, but is not shown. There is no particular limit to the type of electrolyte as long as it does not impair the performance of the energy storage element 10, and various electrolytes can be selected. In addition to the above components, a spacer disposed on the side or below the electrode body 700, an insulating film that wraps the electrode body 700, etc. may be disposed.

[0026] The container 100 is a rectangular parallelepiped (angular or box-shaped) case having a container body 110 with an opening and a lid 120 that closes the opening of the container body 110. The container body 110 is a rectangular tubular member with a bottom that constitutes the main body of the container 100. The container body 110 has a pair of flat and rectangular short side walls on both sides (short side surfaces) in the X-axis direction, a pair of flat and rectangular long side walls on both sides (long side surfaces) in the Y-axis direction, and a flat and rectangular bottom wall on the Z-axis negative direction side. The lid 120 is a rectangular plate-shaped member that constitutes the lid of the container 100, and is arranged extending in the X-axis direction on the Z-axis positive direction side of the container body 110.

[0027] With this configuration, the container 100 is structured so that the inside is sealed by housing the electrode body 700 and the like inside the container body 110 and then joining the container body 110 and the lid body 120 by welding or the like. The material of the container 100 (container body 110 and lid body 120) is not particularly limited, but is preferably a weldable metal such as stainless steel, aluminum, aluminum alloy, iron, or plated steel sheet.

[0028] The lid 120 is formed with a through hole 130 and a gas exhaust valve 140. The gas exhaust valve 140 is a safety valve that releases pressure when the pressure inside the container 100 increases. The through hole 130 is a liquid injection port formed in the lid 120 for injecting an electrolyte into the container 100 during the manufacture of the energy storage element 10. In this embodiment, the through hole 130 is disposed near the negative X-axis direction of the lid 120 and at the center in the Y-axis direction, but the through hole 130 may be disposed at any position in the lid 120. A detailed description of the configuration around the through hole 130 of the lid 120 will be given later.

[0029] The blocking member 200 is a member that blocks the through-hole 130 of the lid 120 of the container 100. Specifically, the blocking member 200 is a liquid injection plug that is joined to the container 100 (lid 120) to block the through-hole 130 after the electrolyte is injected into the container 100 from the through-hole 130 during the manufacture of the energy storage device 10. The material of the blocking member 200 is not particularly limited, and any metal that can be used for the container 100 can be used. In particular, the blocking member 200 is formed of a material that can be 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 blocking member 200 will be given later.

[0030] The electrode body 700 is an electricity storage element (power generation element) that includes a positive electrode plate, a negative electrode plate, and a separator and can store electricity. The positive electrode plate is an electrode plate in which a positive electrode active material layer is formed on a positive electrode base layer that is a long strip-shaped current collector foil made of aluminum or an aluminum alloy. The negative electrode plate is an electrode plate in which a negative electrode active material layer is formed on a negative electrode base layer that is a long strip-shaped current collector foil made of copper or a copper alloy. As the positive electrode active material and the negative electrode active material used in the positive electrode active material layer and the negative electrode active material layer, any known material can be used as long as they are active materials that can absorb and release lithium ions. The separator can be a microporous sheet or nonwoven fabric made of resin.

[0031] The electrode body 700 is formed by stacking a positive electrode plate, a negative electrode plate, and a separator. Specifically, the electrode body 700 is formed by winding a separator disposed between the positive electrode plate and the negative electrode plate. More specifically, the electrode body 700 is wound with the positive electrode plate and the negative electrode plate shifted from each other in the direction of the winding axis via the separator. The winding axis is a virtual axis that serves as the central axis when winding the positive electrode plate and the negative electrode plate, and in this embodiment, it is a straight line that passes through the center of the electrode body 700 and is parallel to the X-axis direction. The positive electrode plate and the negative electrode plate have a portion (active material layer non-formed portion) where the active material is not formed (coated) and the base material layer is exposed at the end 710 in the shifted direction. In this embodiment, an oval shape is illustrated as the cross-sectional shape of the electrode body 700, but it may be a circle, an ellipse, a polygon, or the like.

[0032] The electrode terminals 300 are terminal members (positive electrode terminal and negative electrode terminal) electrically connected to the electrode body 700 via the current collector 600. In other words, the electrode terminals 300 are metal members for leading out electricity stored in the electrode body 700 to the external space of the energy storage element 10 and for introducing electricity into the internal space of the energy storage element 10 to store electricity in the electrode body 700. The electrode terminals 300 are formed of a conductive member such as a metal, such as aluminum, an aluminum alloy, copper, or a copper alloy. The electrode terminals 300 are connected (joined) to the current collector 600 by crimping, welding, or the like, and are attached to the lid 120.

[0033] The upper gasket 400 is a plate-like rectangular member (positive electrode upper gasket and negative electrode upper gasket) that is disposed between the lid 120 of the container 100 and the electrode terminal 300, and insulates and seals between the lid 120 and the electrode terminal 300. The lower gasket 500 is a plate-like rectangular member (positive electrode lower gasket and negative electrode lower gasket) that is disposed between the lid 120 of the container 100 and the current collector 600, and insulates between the lid 120 and the current collector 600. The upper gasket 400 and the lower gasket 500 may be formed of any material as long as they have insulating properties, and are formed of insulating materials such as polypropylene (PP), polyethylene (PE), and polystyrene (PS).

[0034] The current collectors 600 are disposed on both sides of the electrode body 700 in the X-axis direction, and are connected (joined) to the end 710 of the electrode body 700 and the electrode terminal 300, and are current collecting members (positive and negative current collectors) having conductivity and rigidity that electrically connect the electrode body 700 and the electrode terminal 300. The current collectors 600 are fixedly connected (joined) to the lid 120. The material of the current collectors 600 is not particularly limited, but for example, the positive electrode side current collector 600 is formed of aluminum or an aluminum alloy, etc., similar to the positive electrode base layer of the electrode body 700, and the negative electrode side current collector 600 is formed of copper or a copper alloy, etc., similar to the negative electrode base layer of the electrode body 700.

[0035] [2. Description of the Surroundings of the Through-hole 130 of the Lid 120 and the Closing Member 200] Next, the configuration of the periphery of the through hole 130 of the lid 120 and the configuration of the blocking member 200 will be described in detail. FIG. 3 is a perspective view and a cross-sectional view showing the configuration of the periphery of the through hole 130 of the lid 120 and the blocking member 200 according to this embodiment. Specifically, FIG. 3(a) is an enlarged perspective view showing the periphery of the through hole 130 of the lid 120 and the blocking member 200 shown in FIG. 2. FIG. 3(b) is a cross-sectional view showing a cross section of the configuration of FIG. 3(a) cut along a plane including the central axis of the through hole 130 and parallel to the XZ plane. FIG. 4 is a cross-sectional view showing a configuration in which the blocking member 200 is joined to the lid 120 according to this embodiment. Specifically, FIG. 4(a) shows a state in which the blocking member 200 is attached to the lid 120, and FIG. 4(b) shows a state in which the blocking member 200 is joined to the lid 120.

[0036] As shown in these figures, the through hole 130 is a through hole (pouring hole) that penetrates the lid body 120 in the Z-axis direction and is circular when viewed from the Z-axis direction (when viewed from above), and the electrolyte is poured into the container 100 through the through hole 130. A container first recess 131 is formed around the through hole 130. The container first recess 131 is an annular recess when viewed from the Z-axis direction, recessed in the Z-axis negative direction from the outer surface 121 of the lid body 120 in the Z-axis positive direction so as to surround the periphery of the through hole 130. That is, the outer surface 121 of the lid body 120 is recessed to form the container first recess 131, and the through hole 130 is formed inside the container first recess 131 and in the center of the container first recess 131 when viewed from the Z-axis direction.

[0037] The closing member 200 is a member (liquid filling plug) that is joined to the lid 120 by welding in a state in which the closing member 200 closes the through-hole 130. The closing member 200 has a main body portion 210 and a shaft portion 220.

[0038] The main body 210 is disposed in the Z-axis positive direction of the through hole 130 and the container first recess 131, and is the main body of the closing member 200 covering the through hole 130 and the container first recess 131. The main body 210 is a circular (disk-shaped) portion (flange portion) located on the Z-axis positive side of the closing member 200 when viewed from the Z-axis direction, and is joined to the lid 120 in a state of covering the entire through hole 130 and the container first recess 131. The main body 210 is provided with a closing member first recess 211, a closing member second recess 212, and a closing member outer circumferential portion 213.

[0039] The blocking member first recess 211 is disposed at the center position of the outer surface (surface in the positive direction of the Z axis) of the main body 210, and is a generally conical recess recessed toward the negative direction of the Z axis. The blocking member first recess 211 is used, for example, as a mark when joining the blocking member 200 to the lid 120. In other words, since the position of the blocking member 200 can be grasped by the blocking member first recess 211, the blocking member 200 can be placed at an accurate position on the lid 120 and joined to the lid 120.

[0040] The blocking member second recess 212 is an annular recess as viewed from the Z-axis direction, in which the surface of the body portion 210 in the negative Z-axis direction is recessed in the positive Z-axis direction so as to surround the periphery of the shaft portion 220. The blocking member second recess 212 is a recess whose cross-sectional shape is rectangular over the entire circumference when cut along a plane including the central axis of the through hole 130. The blocking member second recess 212 has an inner circumference larger than the through hole 130 as viewed from the Z-axis direction, is disposed within the container first recess 131, and has an outer circumference larger than the container first recess 131.

[0041] The blocking member outer peripheral portion 213 is a convex portion having a circular ring shape as viewed from the Z-axis direction, with the outer peripheral portion including the outer edge of the main body portion 210 protruding in the negative Z-axis direction so as to surround the periphery of the blocking member second recess 212. The blocking member outer peripheral portion 213 is a convex portion whose cross-sectional shape when cut along a plane including the central axis of the through-hole 130 over the entire circumference is rectangular.

[0042] The shaft portion 220 is a protruding portion formed to protrude from the main body portion 210 of the closing member 200, and is inserted into the through-hole 130 of the cover body 120. The shaft portion 220 is a cylindrical portion disposed at the center position of the main body portion 210 when viewed from the Z-axis direction, and extended from the center position in the negative Z-axis direction. The shaft portion 220 has a pillar portion 221 disposed in the negative Z-axis direction of the closing member first recess 211, a reduced diameter portion 222 whose diameter gradually decreases from the pillar portion 221 in the negative Z-axis direction, and a tip portion 223 extended from the reduced diameter portion 222 in the negative Z-axis direction.

[0043] The pillar portion 221 is a cylindrical portion located on the Z-axis positive side of the shaft portion 220. The pillar portion 221 has an outer peripheral shape that is almost the same as the inner peripheral shape of the through hole 130 when viewed from the Z-axis direction. The reduced diameter portion 222 is a truncated cone-shaped portion whose diameter gradually decreases from the end of the pillar portion 221 in the Z-axis negative direction toward the Z-axis negative direction in a cross-sectional shape cut on the XZ plane. The tip portion 223 is a cylindrical portion that extends from the end of the reduced diameter portion 222 in the Z-axis negative direction toward the Z-axis negative direction, and is the tip portion of the shaft portion 220. In this way, the shaft portion 220 has a shape with a tapered tip portion so that it can be easily inserted into the through hole 130 of the lid body 120.

[0044] In this configuration, when the closing member 200 is joined to the lid body 120, the shaft portion 220 of the closing member 200 is inserted (press-fitted) into the through hole 130 of the lid body 120 and engaged with the through hole 130, as shown in (a) of Fig. 4. Also, the closing member outer peripheral portion 213 of the main body portion 210 of the closing member 200 is placed on the outer surface 121 of the lid body 120 while being overlapped and in contact with the outer surface 121. As a result, a first space S1 is formed between the closing member second recess 212 and the outer surface 121, and a second space S2 is formed between the closing member second recess 212 and the container first recess 131.

[0045] The first space S1 is an annular space as viewed from the Z-axis direction, disposed adjacent to the closing member outer peripheral portion 213 on the through-hole 130 side of the closing member outer peripheral portion 213. The second space S2 is an annular space as viewed from the Z-axis direction, disposed connected to the first space S1 on the through-hole 130 side of the first space S1. In other words, the second space S2 is a space disposed between the closing member second recess 212 and the container first recess 131, inside the first space S1 and outside the shaft portion 220 (pillar portion 221).

[0046] In this manner, the first space S1 and the second space S2 are formed by at least one of the container 100 and the closing member 200 being recessed. That is, the first space S1 is formed by the closing member 200 being recessed (the closing member second recess 212 is formed). The second space S2 is formed by the container 100 being recessed (the container first recess 131 is formed) and the closing member 200 being recessed (the closing member second recess 212 is formed). As a result, the second space S2 has a larger volume than the first space S1. That is, the second space S2 is formed so as to have a larger volume (capacity) by being deeper (higher in the Z-axis direction) than the first space S1.

[0047] Then, as shown in FIG. 4B, the blocking member outer peripheral portion 213 of the main body portion 210 of the blocking member 200, which is overlapped with the lid body 120 in the Z-axis direction, is joined to the outer surface 121 of the lid body 120 over the entire circumference. Specifically, a laser beam L is irradiated toward the blocking member outer peripheral portion 213 from the Z-axis positive direction, and the blocking member outer peripheral portion 213 and the outer surface 121 are laser-welded to form a laser welded portion 150 having an annular shape as viewed from the Z-axis direction. That is, the container 100 and the blocking member 200 are arranged overlapping in the penetration direction (Z-axis direction) of the through hole 130, and the overlapped portion is formed with the laser welded portion 150 in which the container 100 and the blocking member 200 are joined by laser welding. The laser welded portion 150 is a fusion portion in which the blocking member outer peripheral portion 213 and the portion on the outer surface 121 side of the lid body 120 are melted by laser welding.

[0048] In this way, the entire outer circumferential portion 213 of the closing member melts to become the laser welded portion 150, so that a space (first space S1 and second space S2) extending from the laser welded portion 150 toward the through hole 130 is formed between the container 100 and the closing member 200. In other words, the first space S1 is a space disposed adjacent to the laser welded portion 150 on the through hole 130 side of the laser welded portion 150.

[0049] [3 Explanation of effects] As described above, according to the energy storage element 10 according to the embodiment of the present invention, the container 100 and the blocking member 200 are arranged overlapping in the penetration direction (Z-axis direction) of the through hole 130 of the container 100, and the laser welded portion 150 is formed in the overlapped portion. A space (first space S1 and second space S2) extending from the laser welded portion 150 toward the through hole 130 is formed between the container 100 and the blocking member 200. Here, if a space extending from the laser welding target portion of the container 100 and the blocking member 200 toward the through hole 130 is formed during laser welding, the gas generated during laser welding escapes into the space, so that the occurrence of pinholes can be suppressed. In other words, if a space extending from the laser welded portion 150 toward the through hole 130 is formed between the container 100 and the blocking member 200, it can be seen that a space extending from the laser welding target portion of the container 100 and the blocking member 200 toward the through hole 130 is formed during laser welding. This allows gas generated during laser welding to escape into the space, thereby suppressing the occurrence of pinholes, resulting in the realization of an energy storage element 10 with improved bonding quality between the container 100 and the blocking member 200.

[0050] A first space S1 is disposed on the through hole 130 side of the laser welded portion 150, and a second space S2 having a larger volume than the first space S1 is disposed on the through hole 130 side of the first space S1, so that gas generated in the laser welded portion 150 escapes to the first space S1 and further escapes to the second space S2. This allows the gas generated in the laser welded portion 150 to escape effectively, thereby improving the joining quality of the container 100 and the closing member 200.

[0051] By recessing at least one of the container 100 and the closing member 200, the space can be easily formed. This makes it possible to easily improve the bonding quality of the container 100 and the closing member 200. In particular, in this embodiment, the first space S1 is formed by recessing the closing member 200. Therefore, the first space S1 can be formed without recessing the container 100 (for example, by utilizing the existing shape of the container 100).

[0052] [4 Explanation of Modifications] (Variation 1) Next, a first modification of the above embodiment will be described. Fig. 5 is a cross-sectional view showing the configuration of the periphery of through-hole 130 of lid 120 and closing member 201 according to the first modification of the present embodiment. Specifically, Fig. 5 shows the configuration in which closing member 201 is joined to lid 120, and corresponds to Fig. 4.

[0053] 5, a blocking member 201 in this modification has a blocking member second recess 214 formed in a main body 210 instead of the blocking member second recess 212 formed in the main body 210 of the blocking member 200 in the above embodiment. The other configurations of this modification are similar to those of the above embodiment, and therefore detailed description thereof will be omitted.

[0054] Unlike the blocking member second recess 212 in the above embodiment, the blocking member second recess 214 is an annular recess as viewed from the Z-axis direction, with the surface of the main body 210 in the negative Z-axis direction curvedly recessed in the positive Z-axis direction. In other words, the blocking member second recess 214 has a curved shape (approximately arc shape) around its entire circumference, with the outer edge shape when cut along a plane including the central axis of the through-hole 130, the width of which decreases toward the positive Z-axis direction.

[0055] In this configuration, similarly to the above embodiment, a first space S3 is formed between the blocking member second recess 214 and the outer surface 121, and a second space S4 is formed between the blocking member second recess 214 and the container first recess 131. The first space S3 is an annular space as viewed from the Z-axis direction, disposed adjacent to the blocking member outer peripheral portion 213 on the through hole 130 side of the blocking member outer peripheral portion 213. The second space S4 is an annular space as viewed from the Z-axis direction, disposed connected to the first space S3 on the through hole 130 side of the first space S3. Then, the blocking member outer peripheral portion 213 of the blocking member 201 and the outer surface 121 of the lid body 120 are laser welded to form a laser welded portion 150. As a result, the first space S3 becomes a space disposed adjacent to the laser welded portion 150 on the through hole 130 side of the laser welded portion 150.

[0056] As described above, the energy storage device according to this modification can achieve the same effects as those of the above embodiment. Note that the shape of the blocking member second recess 214 is not limited to the cross section having a substantially arc shape as shown in Fig. 5, and may be any shape, such as a part of an oval shape, a part of an ellipse shape, or a polygonal shape other than a rectangular shape, such as a triangular shape.

[0057] (Variation 2) Next, a second modification of the above embodiment will be described. Fig. 6 is a cross-sectional view showing the configuration of the periphery of through-hole 130 of lid 120 and closing member 202 according to the second modification of the present embodiment. Specifically, Fig. 6 shows the configuration in which closing member 202 is joined to lid 120, and corresponds to Fig. 4.

[0058] 6, in the closing member 202 of this modification, a protrusion 215 is formed on a main body 210, so that a space (a first space S5 and a second space S2) is formed between the main body 210 and the cover 120. The other configurations of this modification are similar to those of the above embodiment, and therefore detailed description thereof will be omitted.

[0059] The protrusion 215 is a protrusion that protrudes in the negative Z-axis direction from the surface of the body 210 of the closing member 202 in the negative Z-axis direction toward the outer surface 121 of the lid 120 and abuts against the outer surface 121, and is disposed in the first space S5 between the body 210 and the outer surface 121. The protrusion 215 is a cone-shaped protrusion that has a triangular cross-sectional shape when cut along a plane including the central axis of the through-hole 130, and multiple protrusions 215 are disposed in a ring shape at intervals (for example, four protrusions 215 are disposed at equal intervals) along the outer periphery of the body 210. The number and arrangement positions of the protrusions 215 are not particularly limited. The protrusion 215 may be a single ring-shaped protrusion formed continuously along the outer periphery of the body 210 and viewed from the Z-axis direction.

[0060] In this configuration, although the blocking member outer periphery 216 of the main body 210 of the blocking member 202 and the outer surface 121 of the lid 120 are disposed apart from each other, the entire circumference of the blocking member outer periphery 216 is laser welded to the outer surface 121 to form a ring-shaped laser welded portion 160 as viewed from the Z-axis direction. As a result, the first space S5 becomes a ring-shaped space as viewed from the Z-axis direction, which is disposed between the main body 210 and the outer surface 121 and adjacent to the laser welded portion 160 on the through-hole 130 side of the laser welded portion 160.

[0061] As described above, the energy storage element according to this modification can achieve the same effect as the above embodiment. In this modification, the cover 120 may have a protrusion, instead of the blocking member 202 having the protrusion 215. That is, at least one of the container 100 (cover 120) and the blocking member 202 may have a protrusion that protrudes toward the other and abuts against the other, and is disposed in the space (first space S5). In this way, by providing at least one of the container 100 and the blocking member 202 with a protrusion that abuts against the other, the above space is formed by the protrusion, and therefore the above space can be easily formed. This makes it possible to easily improve the joining quality of the container 100 and the blocking member 202.

[0062] (Variation 3) Next, a third modification of the above embodiment will be described. Fig. 7 is a perspective view and a cross-sectional view showing the configuration of the periphery of the through-hole 130 of the lid 120a and the closing member 203 according to the third modification of the present embodiment. Fig. 8 is a cross-sectional view showing the configuration in which the closing member 203 is joined to the lid 120a according to the third modification of the present embodiment. Specifically, Figs. 7 and 8 correspond to Figs. 3 and 4.

[0063] As shown in Figs. 7 and 8, in this modification, the container 100 has a lid 120a, and in addition to the container first recess 131, the container second recess 132 is formed in the lid 120a around the through hole 130. Also, in this modification, the blocking member 203 does not have the blocking member second recess 212 formed in the body 210 of the blocking member 200 in the above embodiment formed in the body 210. Therefore, the blocking member outer peripheral portion 213 is not a convex portion as in the above embodiment, but is the outer peripheral portion of the flat body 210. The other configurations of this modification are the same as those of the above embodiment, and therefore detailed description will be omitted.

[0064] The container second recess 132 is an annular recess as viewed from the Z-axis direction, recessed from the outer surface 121 of the lid body 120a in the Z-axis positive direction in the Z-axis negative direction so as to surround the periphery of the container first recess 131. The outer periphery of the container second recess 132 as viewed from the Z-axis direction is smaller than the outer edge of the main body 210 of the closing member 203. That is, the outer surface 121 of the lid body 120a is recessed to form the container second recess 132, and the container first recess 131 is formed inside the container second recess 132 and at the center of the container second recess 132 as viewed from the Z-axis direction. Then, the through hole 130 is formed inside the container first recess 131 and at the center of the container first recess 131 as viewed from the Z-axis direction.

[0065] In this configuration, when the closing member 203 is joined to the lid body 120a, as shown in (a) of Fig. 8, the closing member outer peripheral portion 213 of the main body portion 210 of the closing member 203 is placed on the outer surface 121 of the lid body 120a while overlapping and abutting the outer surface 121. As a result, a first space S6 is formed between the main body portion 210 and the container second recess 132, and a second space S7 is formed between the main body portion 210 and the container first recess 131.

[0066] Then, as shown in FIG. 8B, the entire circumference of the blocking member outer periphery 213 of the main body 210 of the blocking member 203 and the outer surface 121 of the lid 120a are laser welded to form the laser welded portion 150. As a result, the first space S6 is disposed between the blocking member 203 and the lid 120a, and is disposed adjacent to the laser welded portion 150 on the through hole 130 side of the laser welded portion 150, and is an annular space as viewed from the Z axis direction. The second space S7 is disposed on the through hole 130 side of the first space S6, connected to the first space S6, and is an annular space as viewed from the Z axis direction. In other words, the entire blocking member outer periphery 213 melts to form the laser welded portion 150, and thus a space (the first space S6 and the second space S7) extending from the laser welded portion 150 toward the through hole 130 is formed between the lid 120a and the blocking member 203.

[0067] In this manner, the first space S6 and the second space S7 are formed by the container 100 (the lid 120a) being recessed. That is, the first space S6 and the second space S7 are formed by the lid 120a being recessed (the container second recess 132 and the container first recess 131 are formed). As a result, the second space S7 is formed to have a larger volume (capacity) than the first space S6 by being deeper (having a higher height in the Z-axis direction).

[0068] As described above, the energy storage element according to this modification can achieve the same effects as those of the above-described embodiment. In particular, in this modification, the container 100 (lid 120a) is recessed to form the spaces (first space S6 and second space S7), and therefore the spaces can be easily formed. In other words, since recessing the lid 120a is easier than machining the closing member 203 into a complex shape with recesses, the spaces can be easily formed. This makes it easy to improve the bonding quality between the container 100 and the closing member 203.

[0069] In this modification, blocking member 203 may be replaced by blocking member 200 of the above embodiment, blocking member 201 of modification 1, or blocking member 202 of modification 2.

[0070] (Variation 4) Next, a fourth modification of the above embodiment will be described. Fig. 9 is a cross-sectional view showing the configuration of the periphery of the through-hole 130 of the lid 120 and the closing member 204 according to the fourth modification of the present embodiment. Specifically, Fig. 9 shows a state in which the closing member 204 is joined to the lid 120, and corresponds to (b) of Fig. 4.

[0071] 9, a blocking member 204 in this modification has a notch 224 formed in a shaft portion 220. The other configurations of this modification are similar to those of the above embodiment, and therefore detailed description thereof will be omitted.

[0072] The notch 224 is a notch-shaped portion formed on the side surface of the shaft 220 (the column 221) in the negative X-axis direction. That is, by forming the notch 224, the side surface of the shaft 220 in the negative X-axis direction is formed, for example, in a flat shape. As a result, a gap S8 is formed between the side surface of the shaft 220 in the negative X-axis direction and the inner surface of the through-hole 130 in the negative X-axis direction, which penetrates the lid 120 and is connected to the second space S2. In this way, a gap S8 is formed between the shaft 220 and the inner surface of the through-hole 130, which is connected to the space (second space S2) and penetrates the container 100 (the lid 120).

[0073] As described above, the energy storage element according to this modification can achieve the same effects as those of the above-mentioned embodiment. In particular, in this modification, a gap S8 that is connected to the above-mentioned space (second space S2) is formed between the shaft portion 220 of the closing member 204 and the inner surface of the through hole 130 of the container 100, so that the gas generated at the laser welded portion 150 can escape into the container 100 through the gap S8. This allows the gas generated at the laser welded portion 150 to escape effectively, thereby improving the joining quality of the container 100 and the closing member 204.

[0074] In this modification, the notch 224 may be a notch of any shape, and may be formed on any side surface of the shaft portion 220, such as the side surface of the shaft portion 220 in the positive direction of the X-axis. The entire circumference of the shaft portion 220 may be cut out, and a circular gap may be formed between the entire circumference of the shaft portion 220 and the inner surface of the through-hole 130, the circular gap penetrating the cover 120 and connected to the second space S2 when viewed from the Z-axis direction. In the configurations of the above modifications 1 to 3, the notch 224 may be formed in the blocking members 201 to 203.

[0075] (Other variations) Although the energy storage element according to the embodiment of the present invention (including its modified examples, the same applies below) 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 equivalent to the claims.

[0076] For example, in the above embodiment, the through-hole 130 is formed in the lid of the container 100, and the closing member is joined to the lid. However, the through-hole 130 may be formed in the container body 110 of the container 100, and the closing member may be joined to the container body 110.

[0077] In the above embodiment, the through hole 130 is a liquid inlet for injecting an electrolyte, and the blocking member is a liquid inlet plug. However, the through hole 130 is not limited to a liquid inlet, but may be any through hole formed in the container 100, and the blocking member is not limited to a liquid inlet plug, but may be any member that blocks the through hole 130. For example, the through hole 130 may be a through hole formed in the center of the lid, and the blocking member may block the through hole 130 to form the gas release valve 140.

[0078] In the above embodiment, the outer periphery of the closing member (the outer periphery of the closing member) is laser welded to the container 100 to form the laser welded portion. However, the laser welded portion may be formed by laser welding a portion of the closing member that is more inward than the outer periphery to the container 100. Even in this case, it is sufficient that a space extending from the laser welded portion toward the through hole 130 is formed between the container 100 and the closing member.

[0079] In the above embodiment, the second space has a larger volume (capacity) than the first space. However, the second space may have the same volume as the first space, or may have a smaller volume than the first space.

[0080] In the above embodiment, the container first recess 131 is formed around the through hole 130. However, the container first recess 131 does not have to be formed around the through hole 130. In other words, the second space may not be formed between the container 100 and the closing member, and the first space may extend from the laser welded portion toward the through hole 130.

[0081] In the above embodiment, the closing member has the shaft portion 220 that is inserted into the through hole 130. However, the closing member may have a configuration that does not have the shaft portion 220, and the through hole 130 is closed by joining the main body portion 210 to the container 100. The main body portion 210 of the closing member may not have the closing member first recess 211.

[0082] In the above embodiment, the above configuration (laser welds are formed, and a space extending from the laser welds toward the through hole 130 is formed between the container 100 and the closing member, etc.) is applied around the entire circumference of the through hole 130. However, the above configuration may not be applied to a part of the circumference of the through hole 130. That is, in a part of the circumference of the through hole 130, a laser weld may not be formed, a space may not be formed extending from the laser welds toward the through hole 130, or other configurations described above may not be present.

[0083] In the above embodiment, the electrode body 700 is a so-called vertically wound electrode body whose winding axis is parallel to the cover. However, the electrode body 700 may be a so-called horizontally wound electrode body whose winding axis is perpendicular to the cover. The shape of the electrode body 700 is not limited to the winding type, and may be a stack type in which flat electrode plates are stacked, or a shape in which the electrode plates and / or separators are folded in a bellows shape (a shape in which the separator is bellows-shaped and a rectangular electrode plate is sandwiched between it, a shape in which the electrode plates and the separator are stacked and then bellows-shaped, etc.). In these cases, the end 710 may be a tab protruding from the main body of the electrode body 700.

[0084] Any combination of the components included in the above-described embodiment and its modified examples is also included within the scope of the present invention.

[0085] 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]

[0086] The present invention can be applied to an energy storage device such as a lithium ion secondary battery. [Explanation of symbols]

[0087] 10 Energy storage element 100 containers 110 Container body 120, 120a lid body 121 Exterior 130 Through hole 131 container first recess 132 Second recess of container 150, 160 Laser welded section 200, 201, 202, 203, 204 Closure members 210 Main body 211 Closure member first recess 212, 214 Closure member second recess 213, 216 Outer periphery of blocking member 215 Protrusion 220 Shaft 224 Notch 300 Electrode terminal 600 Current collector 700 Electrode body S1, S3, S5, S6 First space S2, S4, S7 Second space S8 Gap

Claims

1. A container having a through hole formed therein; a closing member joined to the container to close the through hole, the container and the closing member are arranged in a stacked manner in a penetration direction of the through hole, and a laser welded portion is formed at the stacked portion by joining the container and the closing member by laser welding, a space is formed between the container and the closing member, the space extending from the laser welded portion toward the through hole; The blocking member has a shaft portion that is inserted into the through hole, The space is a first space arranged adjacent to the laser weld on the through hole side of the laser weld; a second space that is connected to the first space and is disposed on the through hole side of the first space and has a larger volume than the first space; Energy storage element.

2. A container having a through hole formed therein; a closing member joined to the container to close the through hole, the container and the closing member are arranged in a stacked manner in a penetration direction of the through hole, and a laser welded portion is formed at the stacked portion by joining the container and the closing member by laser welding, a space is formed between the container and the closing member, the space extending from the laser welded portion toward the through hole; The blocking member has a shaft portion that is inserted into the through hole, The space is formed by recessing both the periphery of the through hole in the container and the closing member. Energy storage element.

3. A gap is formed between the shaft portion and the inner surface of the through hole, the gap being connected to the space and penetrating the container. The energy storage element according to claim 1 or 2.

4. At least one of the container and the closing member has a protrusion that protrudes toward the other and abuts against the other, the protrusion being disposed within the space. The energy storage element according to any one of claims 1 to 3.

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