Power storage device

Abstract

To provide a power storage device that is equipped with an exterior body and has improved reliability.SOLUTION: A power storage device 1 comprises an exterior body 10 that accommodates a power storage element 20. The exterior body 10 comprises a first member (exterior body main body 110) and a second member (lid body 120). The exterior body main body 110 has a wall portion 115 provided in a state of being erected along a first direction (Z-axis direction). The lid body 120 has a groove portion 127 into which the wall portion 115 is inserted in the Z-axis direction and is bonded to the wall portion 115 with an adhesive 180. In a second direction, which is a thickness direction of the wall portion 115, a protrusion 121 is provided between a first side surface 115b being a side surface facing the interior of the exterior body 10, of the wall portion 115, and a second side surface 127b being an inside surface facing the first side surface 115b, of the groove portion 127, the protrusion protruding from one of the first side surface 115b and the second side surface 127b toward the other thereof.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to an electricity storage device including an exterior body. [Background technology]

[0002] Patent Document 1 discloses an electricity storage device including an exterior body. The exterior body has a first exterior body that constitutes the main body of the exterior body and a second exterior body that constitutes a lid. The first exterior body has a first peripheral edge portion that forms a first opening that opens upward. The second exterior body has a second peripheral edge portion and an inner peripheral wall that are double walls. The first peripheral edge portion is inserted between the second peripheral edge portion and the inner peripheral wall and fixed with adhesive. A protrusion is arranged between the first peripheral edge portion and the second peripheral edge portion. This protrusion prevents the adhesive from dripping, and the adhesive above the protrusion is covered by the second peripheral edge portion located outside it. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-152165 Summary of the Invention [Problem to be solved by the invention]

[0004] The exterior of an energy storage device is typically made of resin, for example, for reasons of high insulation and ease of molding. During the manufacturing process of a resin exterior, the wall (the upper end portion of the side wall) forming the opening of the exterior body may warp inward due to shrinkage as the resin material cools and solidifies. That is, when viewed from the opening direction, the longitudinal center of the wall may be displaced more inwardly toward the exterior body than the two ends. In this case, the amount of adhesive inside the groove-shaped portion of the lid that accommodates the wall of the exterior body may be insufficient, potentially reducing the bonding strength of that portion. This can lead to reduced reliability of the energy storage device. In this regard, in the conventional energy storage device described above, a protrusion is disposed on the outside of the first peripheral edge of the first exterior body, but it is difficult for this protrusion to prevent the first peripheral edge from warping inward.

[0005] The present invention was made by the inventor of the present application by focusing on the above-mentioned problem, and aims to provide an electricity storage device having an exterior body and having improved reliability. [Means for solving the problem]

[0006] A storage device according to one aspect of the present invention is a storage device including an outer casing that houses a storage element, wherein the outer casing has a first member and a second member attached to the first member so as to block an opening provided in the first member, the first member having a wall portion arranged around the periphery of the opening and arranged upright along a first direction that is an attachment direction of one of the second member and the first member relative to the other, the second member having a groove portion into which the wall portion is inserted in the first direction and joined to the wall portion with an adhesive, and a convex portion protruding from one of the first side surface and the second side surface toward the other is provided in a second direction that is a thickness direction of the wall portion between a first side surface that is a side surface of the wall portion facing the inside of the outer casing and a second side surface that is an inner side surface of the groove portion facing the first side surface. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a power storage device that includes an exterior body and has improved reliability. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a perspective view showing the appearance of a power storage device according to an embodiment; [Figure 2] FIG. 2 is an exploded perspective view of the electricity storage device according to the embodiment. [Figure 3] FIG. 2 is a perspective cross-sectional view of a lid according to the embodiment. [Figure 4] 1 is a perspective cross-sectional view showing a state in which an exterior body and a lid according to an embodiment are combined together. FIG. [Figure 5] 1 is a cross-sectional view showing a state in which an exterior body and a lid according to an embodiment are combined together. [Figure 6] 1 is a bottom view showing a state before the exterior body and the lid body according to the embodiment are combined together. FIG. [Figure 7] 1 is a bottom view showing the exterior body and the lid body according to the embodiment in a combined state. FIG. [Figure 8] FIG. 2 is an exploded perspective view showing the structural relationship between the lid and the component case according to the embodiment. [Figure 9] 4 is a cross-sectional view showing the structural relationship between the lid and the component case according to the embodiment. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] A storage device according to one aspect of the present invention is a storage device including an outer casing that houses a storage element, wherein the outer casing has a first member and a second member attached to the first member so as to block an opening provided in the first member, the first member having a wall portion arranged around the periphery of the opening and arranged upright along a first direction that is an attachment direction of one of the second member and the first member relative to the other, the second member having a groove portion into which the wall portion is inserted in the first direction and joined to the wall portion with an adhesive, and a convex portion protruding from one of the first side surface and the second side surface toward the other is provided in a second direction that is a thickness direction of the wall portion between a first side surface that is a side surface of the wall portion facing the inside of the outer casing and a second side surface that is an inner side surface of the groove portion facing the first side surface.

[0010] According to this configuration, the first and second members are joined with an adhesive while the wall portion of the first member is inserted into the groove portion of the second member, thereby blocking the opening of the first member with the second member. In this joining structure, a convex portion is provided inside the groove portion of the second member, on the inner side (toward the interior of the exterior body) of the wall portion of the first member. Even if the wall portion is warped (flexed) inward before the first and second members are joined, the convex portion can act on the wall portion and the groove portion to separate the inner surface (first side surface) of the wall portion from the inner surface (second side surface) of the groove portion facing the first side surface. In other words, the convex portion acts on the wall portion and the groove portion to correct the inward warping of the wall portion, thereby ensuring a gap between the first side surface and the second side surface. Therefore, a gap for accommodating the adhesive is ensured on both sides of the wall portion inside the groove, thereby improving the reliability of the joint between the first and second members. In this way, the power storage device according to this embodiment is a power storage device with improved reliability.

[0011] The convex portion may be located between the first side surface and the second side surface, and at an end portion in the first direction that is close to an inner bottom surface that is the bottom surface of the groove portion.

[0012] According to this configuration, when the convex portion is provided on the second side surface, the convex portion is provided at the back of the groove portion, making it easy to form the groove portion by resin molding using a mold. Furthermore, whether the convex portion is provided on the first side surface or the second side surface, the force of the convex portion acts on the tip of the wall portion to separate the first side surface and the second side surface. Therefore, the force (moment) acting on the wall portion to correct the warp of the wall portion becomes relatively large. In other words, the warp of the wall portion is efficiently corrected.

[0013] The groove portion and the wall portion may be arranged to extend in a third direction perpendicular to the first direction and the second direction, and the convex portion may be arranged in multiple locations dispersed in the third direction.

[0014] According to this configuration, gaps for accommodating adhesive located on both sides of the wall in the thickness direction are secured long along the third direction. Furthermore, since the plurality of protrusions are dispersed in the third direction, a relatively large space for accommodating adhesive is secured between two adjacent protrusions in the third direction. Both of these contribute to improving the reliability of the joint between the wall and the groove, which are elongated in the third direction.

[0015] At the position where the convex portion is arranged, the distance between the first side and the second side may be greater than or equal to the distance between a third side, which is the side of the wall portion facing the outside of the outer casing, and a fourth side, which is the inner side of the groove portion facing the third side.

[0016] According to this configuration, the protrusions are formed with a protruding length that moves the position of the wall portion in the second direction inside the groove to the intermediate position of the groove or further from the intermediate position toward the outside of the exterior body. In other words, the protrusions have a protruding length that actively presses the wall portion (first side surface) or the groove portion (second side surface). As a result, the protrusions can more reliably correct the wall portion that was warped inward before the first member and the second member were joined. In other words, a gap can be more reliably secured inside the wall portion within the groove.

[0017] The convex portion may have an inclined surface that is inclined in a direction approaching the second side surface as it becomes farther away from the bottom surface of the groove portion in the first direction.

[0018] According to this configuration, when the convex portion is provided on the second side surface of the groove, the wall portion can be guided in a direction away from the second side surface by the inclined surface of the convex portion when it is inserted into the groove. Similarly, when the convex portion is provided on the first side surface of the wall portion, the inclined surface of the convex portion can be guided in a direction away from the second side surface when it is inserted into the groove. In other words, in the operation of joining the first member and the second member, the possibility of the wall portion getting caught on the convex portion when the wall portion is inserted into the groove is reduced, thereby allowing the operation to be performed efficiently.

[0019] The convex portion may be provided at the center of one side of one of the wall portion and the groove portion, which are formed in a polygonal shape when viewed from the first direction.

[0020] When viewed from the first direction, the center of one side of a polygonal wall portion is the portion that experiences the greatest displacement when that side warps inward. Therefore, by providing a convex portion in this center portion or by providing a convex portion in the groove portion so that it contacts this center portion, the warping of the wall portion can be efficiently corrected. Therefore, for example, without providing numerous convex portions, gaps for accommodating adhesive can be secured on both sides of the wall portion. In other words, the proportion of the internal volume of the groove portion consumed by the convex portion can be reduced, and both sides of the wall portion in the second direction can be joined to the groove portion with adhesive.

[0021] Hereinafter, with reference to the drawings, a description will be given of an energy storage device according to an embodiment of the present invention (including its modified examples). Note that the embodiments described below all show comprehensive or specific examples. The numerical values, shapes, materials, components, component placement and connection configurations, manufacturing processes, and the order of manufacturing processes shown in the following embodiments are merely examples and are not intended to limit the present invention. Furthermore, in each drawing, dimensions and the like are not strictly illustrated. Furthermore, in each drawing, the same or similar components are assigned the same reference numerals.

[0022] In the following description and drawings, the longitudinal direction of the exterior body of the energy storage device, or the direction in which the short sides of the energy storage elements face each other, is defined as the X-axis direction. The lateral direction of the exterior body of the energy storage device, or the arrangement direction of multiple energy storage elements, is defined as the Y-axis direction. The arrangement direction of the exterior body main body and the lid body in the exterior body of the energy storage device, or the up-down direction, is defined as the Z-axis direction. These X-axis, Y-axis, and Z-axis directions intersect each other (orthogonal in this embodiment). Note that depending on the mode of use, the Z-axis may not be the up-down direction, but for convenience of explanation, the following description will be made assuming that the Z-axis direction is the up-down direction.

[0023] In the following description, for example, the positive X-axis direction refers to the direction of the arrow on the X-axis, and the negative X-axis direction refers to the direction opposite to the positive X-axis direction. The same applies to the Y-axis and Z-axis directions. When simply referring to the "X-axis direction," it means either one or both directions parallel to the X-axis. The same applies to terms related to the Y-axis and Z-axis.

[0024] 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, "two directions are perpendicular" does not only mean that the two directions are completely perpendicular, but also means that the two directions are substantially perpendicular, i.e., that there is a difference of, for example, a few percent. In the following description, when the term "insulation" is used, it means "electrical insulation."

[0025] (Embodiment) [1. General description of the power storage device] First, an overall description of an energy storage device 1 according to an embodiment will be given using Figures 1 and 2. Figure 1 is a perspective view showing the appearance of the energy storage device 1 according to an embodiment. Figure 2 is an exploded perspective view of the energy storage device 1 according to an embodiment. Figure 2 illustrates a state in which the cover 120 of the exterior body 10 is separated from the exterior body main body 110, exposing a plurality of energy storage elements 20 (energy storage element units 24).

[0026] The power storage device 1 is a device that can charge with electricity from an external source and discharge electricity to the outside, and in this embodiment, has a substantially rectangular parallelepiped shape. The power storage device 1 is, for example, a battery module (battery assembly) used for power storage or power supply purposes. Specifically, the power storage device 1 is used as a battery for driving or starting the engine of a mobile object such as an automobile, motorcycle, personal watercraft, ship, snowmobile, agricultural machinery, construction machinery, or electric railway vehicle. Examples of the automobile include an electric vehicle (EV), a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), and a fossil fuel (gasoline, diesel, liquefied natural gas, etc.) vehicle. Examples of the electric railway vehicle include a train, a monorail, a linear motor car, and a hybrid train equipped with both a diesel engine and an electric motor. The power storage device 1 can also be used as a stationary battery for home or business use.

[0027] As shown in FIGS. 1 and 2, the energy storage device 1 includes energy storage elements 20 and an exterior body 10 that houses the energy storage elements 20. In this embodiment, four energy storage elements 20 are housed in the exterior body 10. The number of energy storage elements 20 included in the energy storage device 1 is not limited to four. The energy storage device 1 may include one or more energy storage elements 20. In this embodiment, one energy storage element unit 24 is configured by four energy storage elements 20 arranged in the Y-axis direction. The energy storage element unit 24 may include a spacer, an insulating film, etc., which are not shown.

[0028] The exterior body 10 has an exterior body main body 110 that houses the energy storage element unit 24, and a lid body 120 that closes an opening 111 of the exterior body main body 110. In the present embodiment, the exterior body main body 110 is an example of a first member, and the lid body 120 is an example of a second member. Inside the exterior body 10, above the energy storage element unit 24, bus bars electrically connected to the multiple energy storage elements 20, bus bar plates that hold the bus bars, and the like are arranged, but illustrations and descriptions of these members are omitted.

[0029] The exterior body 10 is a substantially rectangular parallelepiped (box-shaped) container (module case) that forms the outer shell of the energy storage device 1. In other words, the exterior body 10 is a member that secures the energy storage element units 24, bus bar plates, etc. in predetermined positions and protects them from impacts and the like. The exterior body 10 is formed from an insulating member such as polycarbonate (PC), polypropylene (PP), polyethylene (PE), polystyrene (PS), polyphenylene sulfide resin (PPS), polyphenylene ether (PPE (including modified PPE)), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyether ether ketone (PEEK), tetrafluoroethylene-perfluoroalkyl vinyl ether (PFA), polytetrafluoroethylene (PTFE), polyethersulfone (PES), polyamide (PA), ABS resin, or a composite material thereof.

[0030] The exterior body 10 has an exterior body main body 110, which is a bottomed rectangular cylindrical housing having an opening 111 formed therein for accommodating the energy storage element unit 24. The lid 120 is a rectangular member that closes the opening 111 of the exterior body main body 110, and has a positive electrode external terminal 91 and a negative electrode external terminal 92. The external terminals 91 and 92 are electrically connected to the multiple energy storage elements 20, and the energy storage device 1 charges with electricity from the outside and discharges electricity to the outside via these external terminals 91 and 92. The external terminals 91 and 92 are formed of a conductive member made of metal such as aluminum or an aluminum alloy.

[0031] In this embodiment, wall 115 of exterior body 110 is inserted into groove 127 of lid 120 and fixed thereto with an adhesive. Details of the joint between exterior body 110 and lid 120 will be described later using FIGS. 3 to 7. In this embodiment, exterior body 10 further has a component case 210 that houses components such as a control circuit, not shown in FIGS. 1 and 2. Component case 210 is joined and fixed to the inside of lid 120. The configuration of component case 210 and its surroundings will be described later using FIGS. 7 to 9.

[0032] The energy storage elements 20 are secondary batteries (single cells) that can charge and discharge electricity, and more specifically, non-aqueous electrolyte secondary batteries such as lithium ion secondary batteries. The energy storage elements 20 have a flattened rectangular parallelepiped (rectangular) shape, and in this embodiment, four energy storage elements 20 are arranged in the Y-axis direction as described above.

[0033] The energy storage element 20 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 20 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 20 may be a battery that uses a solid electrolyte. The energy storage element 20 may be a pouch-type energy storage element. The shape of the energy storage element 20 is not limited to the above-mentioned rectangular shape, and may be other shapes such as a polygonal prism, a cylindrical shape, an elliptical cylindrical shape, or an oblong cylindrical shape.

[0034] In this embodiment, the energy storage element 20 includes a metal container 21. The container 21 is a rectangular case having a pair of opposing long sides 21a and a pair of opposing short sides 21b. The container 21 contains an electrode assembly, a current collector, an electrolyte, and the like. In this embodiment, the multiple energy storage elements 20 are aligned in a row in the Y-axis direction with their long sides 21a facing the Y-axis direction (with their short sides 21b parallel to the Y-axis direction).

[0035] Metallic electrode terminals 22 (positive and negative electrode terminals) are provided on the cover plate 21c of the container 21 and are electrically connected to the electrode body inside the container 21. The electrode terminals 22 are arranged to protrude upward (in the positive direction of the Z axis) from the cover plate 21c of the container 21. The cover plate 21c of the container 21 is further provided with a gas exhaust valve 23 for exhausting internal gas to the outside when the internal pressure of the container 21 rises excessively.

[0036] In the energy storage device 1 having such a basic configuration, the opening 111 of the exterior body 110 is sealed by the lid 120. Specifically, if the gas exhaust valve 23 of the energy storage element 20 opens and gas is released, for example, to ensure the safety of the user of the energy storage element 20, the gas needs to be guided to a predetermined location through an exhaust port (not shown) provided in the exterior body 10. However, if there is a gap at the joint between the exterior body 110 and the lid 120, or if a gap is created due to gas pressure, gas will leak from an unexpected location, which could cause an unsafe event. Furthermore, the energy storage device 1 may be used in situations exposed to wind and rain, or may be submerged due to a natural disaster or other cause. Therefore, the joint between the exterior body 110 and the lid 120 may be required to be highly airtight or watertight. Therefore, the joint between the exterior body 110 and the lid 120 is an important part from the perspective of maintaining or improving the reliability of the energy storage device 1.

[0037] Therefore, this embodiment employs a configuration for improving the reliability of the joint between exterior body 110 and lid 120. Hereinafter, the joint between exterior body 110 and lid 120 according to this embodiment will be described in detail with reference to Figs. 3 to 7.

[0038] [2. Regarding the joint between the exterior body and the lid] FIG. 3 is a perspective cross-sectional view of the lid 120 according to the embodiment. FIG. 3 illustrates a cross-section of the groove 127 of the lid 120 in the YZ plane passing through line III-III in FIG. 2. FIG. 4 is a perspective cross-sectional view showing the exterior body main body 110 and the lid 120 according to the embodiment in a combined state. The position of the cross-section in FIG. 4 corresponds to the position of the cross-section in FIG. 3. FIG. 5 is a cross-sectional view showing the exterior body main body 110 and the lid 120 according to the embodiment in a combined state. FIG. 5 illustrates a cross-section of the groove 127 and the wall 115 in the YZ plane passing through line VV in FIG. 3. FIG. 6 is a view (bottom view) seen from the negative Z-axis direction showing the exterior body main body 110 and the lid 120 according to the embodiment in a state before they are combined. FIG. 7 is a bottom view showing the exterior body main body 110 and the lid 120 according to the embodiment in a combined state. In FIGS. 6 and 7, the approximate shape of wall portion 115 of exterior body main body 110 is schematically shown by a thick dotted line.

[0039] 2 and 3 to 7, the lid 120 is a member that is attached from the opening direction of the opening 111 of the exterior body main body 110 (positive direction of the Z axis) toward the exterior body main body 110. The exterior body main body 110 has a wall portion 115 provided on the periphery of the opening 111. The lid 120 has a groove portion 127 into which the wall portion 115 of the exterior body main body 110 is inserted.

[0040] Wall 115 of exterior body main body 110 is provided standing along the mounting direction (Z-axis direction) of one of lid 120 and exterior body main body 110 relative to the other. This mounting direction (Z-axis direction) is an example of a first direction, and the thickness direction of wall 115 (Y-axis direction in FIGS. 3 to 5), which is perpendicular to the mounting direction, is an example of a second direction.

[0041] In this embodiment, as shown in FIGS. 4 and 5 , wall 115 has first side surface 115b, which is a side surface facing the inside of exterior body 10 in the second direction, and groove 127 has second side surface 127b, which is an inner surface facing first side surface 115b. Wall 115 further has third side surface 115a, which is a side surface facing the outside of exterior body 10. The direction meant by "facing the inside of exterior body 10" is the direction from the outside to the inside of exterior body 10 when viewed from the Z-axis direction. For example, focusing on the portion of wall 115 shown in FIG. 4 , the side surface of wall 115 facing the inside of exterior body 10 in the thickness direction of wall 115 (Y-axis direction) is first side surface 115b, which faces the positive direction of the Y-axis. The direction meant by "facing the outside of exterior body 10" is the opposite direction meant by "facing the inside of exterior body 10."

[0042] Groove 127 further has fourth side surface 127a, which is an inner side surface facing third side surface 115a, and inner bottom surface 127c, which is the bottom surface of groove 127. In other words, when wall 115 is inserted into groove 127, wall 115 of exterior body main body 110 is disposed between second side surface 127b and fourth side surface 127a of groove 127 in the second direction. The end face of wall 115 in the positive Z-axis direction is disposed opposite inner bottom surface 127c, which is the bottom surface of groove 127, in the Z-axis direction.

[0043] The lid 120 and exterior body main body 110 configured in this manner are joined together with adhesive 180, as shown in Figures 4 and 5. For example, the lid 120 is turned upside down so that the opening of the groove 127 faces upward, and then adhesive 180 is poured into the groove 127. Furthermore, the wall 115 of the exterior body main body 110 is inserted into the groove 127 of the lid 120 from above (see Figures 3 and 4). Thereafter, the adhesive 180 solidifies (cures), thereby joining the lid 120 and the exterior body main body 110 together.

[0044] Before such joining operation, wall 115 of exterior body main body 110 may be warped inward of exterior body 10 when viewed in the Z-axis direction, as shown in FIG. 6 . Specifically, exterior body 10 (each of exterior body main body 110 and lid body 120) is produced by molding a resin material such as PC, PP, PE, or PS using a mold. During this production process, exterior body main body 110 removed from the mold may deform so as to narrow opening 111 due to shrinkage of the resin material. In this case, as shown in FIG. 6 , wall 115 provided on the periphery of opening 111 warps inwardly of exterior body 10. When wall 115 in this inwardly warped state is inserted into groove 127 of lid body 120, the longitudinal center portion of wall 115, which is the portion of wall 115 with the largest inward displacement, comes into contact with or is close to second side surface 127b of groove 127 (see FIGS. 3 and 4 ). As a result, the amount of adhesive 180 disposed between the central portion of wall portion 115 and second side surface 127b is less than the amount of adhesive 180 disposed between other portions of wall portion 115 and second side surface 127b. More specifically, when a portion of wall portion 115 that has been displaced inward comes into contact with second side surface 127b, adhesive 180 is not disposed between that portion and second side surface 127b. In other words, that portion and second side surface 127b are not bonded to each other. In this way, when wall portion 115 that forms opening 111 of exterior body 110 is warped inward, the bond strength between wall portion 115 and groove portion 127 may be partially reduced.

[0045] Therefore, in the energy storage device 1 according to the present embodiment, even when the wall portion 115 is warped inward, a configuration is adopted in which the wall portion 115 and the groove portion 127 are joined together with the warp corrected. Specifically, as shown in FIGS. 3 to 5 , a protrusion 121 is disposed between a first side surface 115b of the wall portion 115 facing the inside of the exterior body 10 and a second side surface 127b of the groove portion 127 facing the first side surface 115b, to separate the first side surface 115b and the second side surface 127b. In the present embodiment, the second side surface 127b is provided with a protrusion 121 that protrudes from the second side surface 127b toward the first side surface 115b. The protrusion 121 acts between the first side surface 115b and the second side surface 127b so as to press the inwardly warped wall portion 115 outward. 3 to 5, a gap between the first side surface 115b and the second side surface 127b is secured on at least both sides of the protrusion 121 in the X-axis direction, in order to accommodate the adhesive 180. This effect is also achieved when the protrusion 121 is provided so as to protrude from the first side surface 115b of the wall 115 toward the second side surface 127b of the groove 127.

[0046] In this embodiment, as shown in FIGS. 3 to 5 , the protruding length (width in the Y-axis direction) of the protrusion 121 is a length that separates the wall 115 from the second side surface 127b and prevents the wall 115 from contacting the fourth side surface 127a, which is the inner surface of the groove 127 facing the second side surface 127b. Furthermore, no protrusion is disposed on the side of the wall 115 opposite the protrusion 121 in the Y-axis direction (the negative Y-axis direction). Therefore, as shown in FIG. 5 , an adhesive 180 is disposed on the position of the wall 115 opposite the protrusion 121. That is, a portion of the adhesive 180 is disposed between the third side surface 115a of the wall 115 and the fourth side surface 127a of the groove 127, in a range that overlaps with the protrusion 121 when viewed from the second direction (the Y-axis direction). As a result, the fourth side surface 127a and the third side surface 115a of the wall portion 115 are continuously bonded by the adhesive 180 in the direction in which the wall portion 115 and the groove portion 127 extend (the X-axis direction in FIGS. 3 to 5). Furthermore, because the adhesive 180 is disposed on one side of the protrusion 121 in the Z-axis direction (the negative Z-axis direction in FIG. 5), continuity of the bond in the X-axis direction between the first side surface 115b of the wall portion 115 and the second side surface 127b of the groove portion 127 is also ensured. These effects of the protrusion 121 are also achieved when the protrusion 121 is provided so as to protrude from the first side surface 115b of the wall portion 115 toward the second side surface 127b of the groove portion 127. In other words, it is sufficient that the protrusion 121 is provided so as to protrude from one of the first side surface 115b of the wall portion 115 and the second side surface 127b of the groove portion 127 toward the other.

[0047] As described above, the energy storage device 1 according to this embodiment includes an exterior body 10 that houses the energy storage elements 20. The exterior body 10 includes a first member (exterior body main body 110) and a second member (lid body 120) attached to the exterior body main body 110 so as to close an opening 111 provided in the exterior body main body 110. The exterior body main body 110 has a wall portion 115 that is arranged on the periphery of the opening 111 and is provided standing along a first direction (Z-axis direction) that is the attachment direction of one of the lid body 120 and the exterior body main body 110 relative to the other. The lid body 120 has a groove portion 127 into which the wall portion 115 is inserted in the Z-axis direction and which is joined to the wall portion 115 with adhesive 180. In a second direction (the Y-axis direction in Figure 5), which is the thickness direction of the wall portion 115, a convex portion 121 protruding from one of the first side surface 115b and the second side surface 127b to the other is provided between a first side surface 115b of the wall portion 115, which is the side surface facing the inside of the outer casing 10, and a second side surface 127b of the groove portion 127, which is the inner surface facing the first side surface 115b.

[0048] According to this configuration, with wall 115 of exterior body main body 110 inserted into groove 127 of lid 120, exterior body main body 110 and lid 120 are joined together with adhesive 180, thereby closing opening 111 of exterior body main body 110 with lid 120. In this joining structure, protrusion 121 is provided inside groove 127 of lid 120, on the inner side of wall 115 of exterior body main body 110 (on the inner side of exterior body 10). As a result, even if wall 115 is warped inward (flexed) as shown in FIG. 6 before exterior body main body 110 and lid 120 are joined together, protrusion 121 can act on wall 115 and groove 127 to separate the inner surface (first side surface 115b) of wall 115 from the inner surface (second side surface 127b) of groove 127 that faces first side surface 115b. That is, the protrusions 121 act on the wall 115 and the groove 127 so as to correct the inward warping of the wall 115. As a result, the protrusions 121 ensure a gap between the first side surface 115b and the second side surface 127b. Therefore, as shown in FIGS. 5 and 7, a gap for accommodating the adhesive 180 is ensured inside the groove 127 on both sides of the wall 115, thereby improving the reliability of the joint between the exterior body 110 and the lid 120. In this way, the energy storage device 1 according to the present embodiment is an energy storage device with improved reliability.

[0049] In this embodiment, as shown in FIG. 5, the convex portion 121 is located between the first side surface 115b and the second side surface 127b, and at an end in the Z-axis direction close to the inner bottom surface 127c, which is the bottom surface of the groove portion 127.

[0050] As described above, in this embodiment, the convex portion 121 is provided on the second side surface 127b, and its position is at the back of the groove portion 127. Therefore, it is easy to form the groove portion 127 (including the convex portion 121) by resin molding using a mold. Furthermore, whether the convex portion 121 is provided on the first side surface 115b or the second side surface 127b, a force by the convex portion 121 acts on the tip end portion (the end portion in the positive direction of the Z axis) of the wall portion 115 to separate the first side surface 115b and the second side surface 127b. Therefore, a force (moment) acting on the wall portion 115 so as to correct the warpage of the wall portion 115 becomes relatively large. In other words, the warpage of the wall portion 115 is efficiently corrected.

[0051] In this embodiment, as shown in Figures 6 and 7, a plurality of protrusions 121 are arranged inside groove 127. Specifically, groove 127 and wall 115 are arranged to extend in a third direction (the X-axis direction and the Y-axis direction in Figures 6 and 7) that is perpendicular to the first direction and the second direction. A plurality of protrusions 121 are arranged dispersedly in the third direction. The first direction is the attachment direction of one of lid 120 and exterior body main body 110 relative to the other, and the second direction is the thickness direction of wall 115.

[0052] According to this configuration, gaps for accommodating adhesive 180, which are located on both sides of wall 115 in the thickness direction, are secured long along the third direction, which is the direction in which wall 115 and groove 127 extend. Furthermore, since multiple protrusions 121 are dispersedly disposed in the third direction, a relatively large space is secured between two protrusions 121 aligned in the third direction as a space for accommodating adhesive 180. This contributes to improving the reliability of the joint between wall 115 and groove 127, which are both elongated in the third direction.

[0053] 5, in the present embodiment, at the position where protrusion 121 is arranged, distance W1 between first side surface 115b and second side surface 127b is equal to or greater than distance W2 between third side surface 115a of wall portion 115 and fourth side surface 127a of groove portion 127. Third side surface 115a is the side surface of wall portion 115 facing the outside of exterior body 10. Fourth side surface 127a is the inner surface of groove portion 127 facing third side surface 115a.

[0054] As described above, in the present embodiment, convex portion 121 is formed with a protruding length that moves the position of wall portion 115 in groove portion 127 in the Y-axis direction to the intermediate position of groove portion 127 or further away from the exterior of package 10 than the intermediate position. In other words, convex portion 121 has a protruding length that actively presses wall portion 115 (first side surface 115b) or groove portion 127 (second side surface 127b). As a result, convex portion 121 can more reliably correct wall portion 115 that is warped inward before package main body 110 and lid 120 are joined, that is, can more reliably secure a gap on the inside of wall portion 115 within groove portion 127 (the positive direction of the Y-axis in FIG. 5). Furthermore, displacement of wall portion 115 until adhesive 180 solidifies (cures) is more reliably suppressed.

[0055] In this embodiment, as shown in FIGS. 3 to 5, the protrusion 121 has an inclined surface 121a that is inclined in a direction approaching the second side surface 127b as it moves away from the inner bottom surface 127c of the groove 127 in the Z-axis direction.

[0056] In the present embodiment, protrusion 121 is provided on second side surface 127b of groove 127. In this case, when wall 115 is inserted into groove 127, inclined surface 121a of protrusion 121 can guide wall 115 in a direction away from second side surface 127b. Similarly, when protrusion 121 is provided on first side surface 115b of wall 115, inclined surface 121a of protrusion 121 can guide wall 115 in a direction away from second side surface 127b when wall 115 is inserted into groove 127. In other words, in the operation of joining exterior body 110 and lid 120, the possibility of wall 115 getting caught on protrusion 121 is reduced when wall 115 is inserted into groove 127, and this allows the operation to be performed efficiently.

[0057] In this embodiment, opening 111 of exterior body 110 is formed in a polygonal shape when viewed from the Z-axis direction. That is, wall 115 and groove 127 are also formed in a polygonal shape when viewed from the Z-axis direction, as shown in FIG. 6 . Protrusion 121 is provided in the center of one side of one of wall 115 and groove 127, which are formed in a polygonal shape when viewed from the Z-axis direction. The center of one side is a predetermined range including the center of the side in the longitudinal direction, and is, for example, a range with a width of approximately 60% or less of the length of the side. In other words, it is a range excluding both ends of the side in the longitudinal direction (the length of one end is approximately 20% or more of the length of the side).

[0058] The center of one side of polygonal wall portion 115 is a portion that experiences a large amount of displacement when the side is warped inward (see FIG. 6). Therefore, by providing protrusion 121 in groove portion 127 at a position facing the center, or by providing protrusion 121 in the center of wall portion 115, the warping of wall portion 115 can be efficiently corrected. Therefore, for example, without providing a large number of protrusions 121, gaps for accommodating adhesive 180 can be secured on both sides of wall portion 115. In other words, the proportion of the internal volume of groove portion 127 consumed by protrusion 121 can be reduced, and both sides of wall portion 115 in the thickness direction can be joined to groove portion 127 with adhesive.

[0059] In this embodiment, wall portion 115 and groove portion 127 are formed in a rectangular shape whose length in the X-axis direction is longer than its length in the Y-axis direction when viewed from the Z-axis direction. That is, one side of wall portion 115 and groove portion 127 extending in the X-axis direction is longer than one side extending in the Y-axis direction. In this configuration, two protrusions 121 are arranged in the center of one side of groove portion 127 extending in the X-axis direction, and one protrusion 121 is arranged in the center of one side of groove portion 127 extending in the Y-axis direction (see FIG. 7 ). That is, more protrusions 121 are arranged on the longer side. This allows wall portion 115 and groove portion 127 to be joined in an appropriate state with adhesive 180 while correcting the entire inwardly warped wall portion 115 in a balanced manner.

[0060] In the present embodiment, as described above, component case 210 that houses components such as a control circuit is joined to the inside of lid 120, and this joining structure is the same as the joining structure between exterior body 110 and lid 120 described above. The joining portion between lid 120 and component case 210 will be described below with reference to Figs. 7 to 9.

[0061] [3. Regarding the joint between the lid and the component case] Fig. 8 is an exploded perspective view showing the structural relationship between the lid 120 and the component case 210 according to the embodiment. Fig. 8 simply illustrates an electric device 300, which is an example of a component housed in the component case 210. Fig. 9 is a cross-sectional view showing the structural relationship between the lid 120 and the component case 210 according to the embodiment. Fig. 9 illustrates a cross section of the lid 120 and the component case 210 in the XZ plane passing through line IX-IX in Fig. 7. Fig. 9 simply illustrates a side view of the electric device 300 rather than a cross section, and the energy storage element 20 and the like arranged in the negative Z-axis direction of the component case 210 are omitted from the illustration.

[0062] The component case 210 is a component that constitutes a part of the exterior housing 10 and, like the exterior housing 10, is a component that is produced by molding a resin material such as PC, PP, PE, or PS using a mold. As shown in FIGS. 8 and 9 , the component case 210 is fixed to the inside of the lid 120 with adhesive 180. More specifically, the component case 210 has an opening 211 formed by a wall portion 215 that opens in the positive direction of the Z axis. The wall portion 215 is inserted into a groove portion 137 provided in the lid 120 and is bonded to the groove portion 137 with adhesive 180. In other words, in the joining structure shown in FIGS. 8 and 9 , the component case 210 having the wall portion 215 is a first component having the wall portion 215, and the lid 120 having the groove portion 137 into which the wall portion 215 is inserted is a second component. The joining structure shown in FIGS. 8 and 9 can be described, for example, as follows.

[0063] The exterior housing 10 has a first member (component case 210) and a second member (lid 120) attached to the component case 210 so as to close an opening 211 provided in the component case 210. The component case 210 has a wall portion 215 that is arranged on the periphery of the opening 211 and is provided standing along a first direction (Z-axis direction) that is the attachment direction of one of the lid portion 120 and the component case 210 relative to the other. The lid 120 has a groove portion 137 into which the wall portion 215 is inserted in the Z-axis direction and which is joined to the wall portion 215 with adhesive 180. In a second direction (the X-axis direction in Figure 9), which is the thickness direction of wall portion 215, a convex portion 131 protruding from one of first side surface 215b and second side surface 137b to the other is provided between first side surface 215b, which is the side surface of wall portion 215 facing the inside of outer casing 10, and second side surface 137b, which is the inner surface of groove portion 137 facing first side surface 215b.

[0064] As described above, in the present embodiment, the wall 215 of the component case 210 and the groove 137 of the lid 120 are joined together by the adhesive 180. A protrusion 131 is disposed inside the groove 137 of the lid 120, separating the first side surface 215b of the wall 215 from the second side surface 137b of the groove 137. In other words, the joining structure between the component case 210 and the lid 120 is the same as the joining structure between the exterior body 110 and the lid 120 described above.

[0065] Therefore, even if the wall 215 of the component case 210 is warped inward before being joined to the lid 120, the convex portion 131 ensures a gap between the first side surface 215b of the wall 215 and the second side surface 137b of the groove 137. This improves the reliability of the joint between the component case 210 and the lid 120, as well as the joint between the exterior body 110 and the lid 120. This allows the component case 210 to stably retain components (such as the electric device 300) or maintain this retaining function for a long period of time, for example. This contributes to improving the reliability of the electricity storage device 1.

[0066] Furthermore, the protrusions 131 arranged inside the grooves 137 share various characteristics with the protrusions 121 arranged inside the grooves 127 (see FIGS. 3 to 5). That is, the protrusions 131 are arranged at the end portions close to the inner bottom surface 137c, which is the bottom surface of the grooves 137, in the Z-axis direction (see FIG. 9). A plurality of the protrusions 131 are arranged dispersedly in a third direction (the X-axis direction and the Y-axis direction in FIG. 7), which is the direction in which the wall portions 215 and the grooves 137 extend. At the position where the protrusions 131 are arranged, the distance between the first side surface 215b and the second side surface 137b is equal to or greater than the distance between the third side surface 215a of the wall portions 215 and the fourth side surface 137a of the grooves 137. The protrusions 131 have inclined surfaces 131a that are inclined toward the second side surface 137b as they move away from the inner bottom surface 137c of the grooves 137 in the Z-axis direction. The protrusion 131 is provided at the center of one side of the polygonal shape of one of the wall 215 and groove 137 which are formed in a polygonal shape when viewed from the Z-axis direction.

[0067] In this way, the joint structure between component case 210 and lid 120 has various features in common with the joint structure between the above-mentioned exterior body 110 and lid 120. Therefore, various effects that contribute to improving the reliability of the joint portion between component case 210 and lid 120 are achieved.

[0068] The joining structure between component case 210 and lid 120 does not need to have all the features of the joining structure between exterior body 110 and lid 120. It is sufficient that protrusion 131 protruding from one of first side surface 215b and second side surface 137b toward the other is provided between first side surface 215b of wall 215 of component case 210 and second side surface 137b of groove 137 of lid 120.

[0069] Examples of the electrical device 300 housed in the component case 210 include a circuit board that monitors and / or controls the charge and discharge states of the energy storage element unit 24, a relay connected to the energy storage element unit 24, electric / electronic components, or communication equipment for communicating with external devices. Examples of components other than the electrical device 300 housed in the component case 210 include wiring through which a control signal or main current flows, a valve member for discharging gas inside the exterior body 10, and a breathable waterproof film that allows ventilation between the inside and outside of the exterior body 10.

[0070] That is, various components such as an energy storage element 20 (see FIG. 2), an electrical device 300 such as a circuit board (see FIG. 8), electrical / electronic components, wiring, or a valve component can be arranged between the first and second components of the exterior body 10.

[0071] [4. Modifications] Although the energy storage device 1 according to the embodiment of the present invention has been described above, the present invention is not limited to this embodiment. In other words, the embodiment disclosed herein is illustrative in all respects and is not restrictive, and the scope of the present invention includes all modifications within the meaning and scope of the claims.

[0072] The first and second members of the exterior housing 10 are not limited to a combination of the exterior housing main body 110 and the lid body 120, or a combination of the component case 210 and the lid body 120. For example, a wall portion around the periphery of the opening of the lid body 120 serving as the first member may be inserted into a groove portion provided in the exterior housing main body 110 serving as the second member, and the wall portion and the groove portion may be joined with adhesive 180. In other words, the first member may be the lid body 120, and in this case, the second member may be the exterior housing main body 110. The same applies to the combination of the component case 210 and the lid body 120; the first member having the wall portion may be the lid body 120, and in this case, the second member having the groove portion may be the component case 210.

[0073] Assume that an opening is provided on the top surface of lid 120 (the surface in the positive direction of the Z axis, see FIG. 1) for arranging components such as an exhaust valve or for assembling or maintaining power storage device 1, and that the opening is closed with a small lid. In this case, a wall may be provided around the periphery of the opening of lid 120 as a first member, and a groove may be provided on the small lid as a second member, into which the wall of lid 120 is inserted and bonded to the wall with adhesive 180. In this structure, the first and second members may be reversed. In other words, one of the first and second members may be lid 120, and the other of the first and second members may be the small lid described above.

[0074] Component case 210, which constitutes part of exterior body 10, may be fixed to the outer surface of lid 120 instead of the inner surface, or may be fixed to the inner or outer surface of exterior body main body 110.

[0075] It is not essential that the wall portion 115 of the exterior body main body 110 be warped inward before being joined to the lid body 120. Before being joined, the wall portion 115 of the exterior body main body 110 may be formed in a straight line when viewed from the Z-axis direction. When the wall portion 115 is inserted into the groove portion 127, the protrusion 121 provided on one of the groove portion 127 and the wall portion 115 may not be in contact with the other of the groove portion 127 and the wall portion 115. In either case, the protrusion 121 can suppress displacement of the wall portion 115, for example, during the period until the adhesive 180 solidifies (cures). This contributes to improving the reliability of the energy storage device 1.

[0076] 3 to 5, the inclined surface 121a of the protrusion 121 does not need to be formed as a flat surface, but may be formed as, for example, an outwardly convex curved surface. That is, the end of the protrusion 121 in the direction in which the groove 127 opens (the negative Z-axis direction in FIG. 5) may be rounded. Even in this case, the protrusion 121 can guide the wall 115 in a direction away from the second side surface 127b when the wall 115 is inserted into the groove 127.

[0077] The shape of exterior body 10 does not need to be a substantially rectangular parallelepiped (box-like). For example, the joining structures shown in Figures 3 to 5 may be used to join a cylindrical exterior body main body with one end closed to an exterior body configured with a circular lid in a plan view that covers a circular opening.

[0078] The various supplementary points regarding the joining structure between the exterior body 110 and the lid 120 described above may be appropriately adopted in the joining structure between the component case 210 and the lid 120 shown in FIGS.

[0079] Any combination of the components included in the above-described embodiments and their modifications is also included within the scope of the present invention. [Industrial Applicability]

[0080] The present invention can be applied to an electricity storage device including an electricity storage element such as a lithium ion secondary battery. [Explanation of symbols]

[0081] 1. Energy storage device 10. Exterior body 20 Energy storage element 110 Exterior body 111, 211 openings 115, 215 Wall section 115a, 215a third aspect 115b, 215b first aspect 120 Lid 121, 131 convex part 121a, 131a Slope 127, 137 Groove 127a, 137a fourth aspect 127b, 137b second aspect 127c, 137c inner bottom surface 180 Adhesive 210 Parts Case 300 Electrical Equipment

Claims

1. An electricity storage device including an exterior body that houses an electricity storage element, the exterior body includes a first member and a second member attached to the first member so as to close an opening provided in the first member, the first member has a wall portion disposed on a periphery of the opening and provided in an upright state along a first direction that is an attachment direction of one of the second member and the first member relative to the other, the second member has a groove into which the wall portion is inserted in the first direction and which is joined to the wall portion with an adhesive; a convex portion protruding from one of the first side surface and the second side surface toward the other is provided between a first side surface of the wall portion, which is a side surface of the wall portion facing the inside of the exterior body, and a second side surface of the groove portion, which is an inner surface facing the first side surface; the protrusion is disposed between the first side surface and the second side surface and at an end portion close to an inner bottom surface, which is a bottom surface of the groove, in the first direction. Energy storage device.

2. the groove portion and the wall portion are arranged to extend in a third direction perpendicular to the first direction and the second direction, The plurality of convex portions are disposed dispersedly in the third direction. The electricity storage device according to claim 1.

3. At the position where the convex portion is arranged, the distance between the first side surface and the second side surface is equal to or greater than the distance between a third side surface, which is a side surface of the wall portion facing the outside of the exterior body, and a fourth side surface, which is an inner surface of the groove portion facing the third side surface. The electricity storage device according to claim 1 or 2.

4. the protrusion has an inclined surface that is inclined in a direction approaching the second side surface as it becomes farther from the inner bottom surface of the groove in the first direction, The electricity storage device according to any one of claims 1 to 3.

5. the protrusion is provided at a center of one side of the polygonal shape of one of the wall portion and the groove portion, which are formed in a polygonal shape when viewed from the first direction; The electricity storage device according to any one of claims 1 to 4.

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