Storage container

Abstract

The present invention enhances the rigidity of a storage container.　A storage container (10A) comprises: a container (20) which has a bottom part (21) and a wall part (22) that is erected from an outer peripheral part of the bottom part (21); a lid (30A) which has a top plate (31), a first flange (33) that is provided below the top plate (31) and on the outer peripheral part, and a connection part (32) that connects the top plate (31) and the first flange (33), and which is disposed on an upper portion of the wall part (22); and a fastening member (2) which fastens the first flange (33) and the container (20). The lid (30A) is made of metal and / or fiber-reinforced plastic. The first flange (33) has an annular protrusion (35) which protrudes from an upper surface. The protrusion (35) has a wavy shape that is displaced in the inward / outward direction of the storage container (10A) according to the position of the first flange (33) in the circumferential direction.

Description

Storage containers

[0001] This invention relates to a storage container.

[0002] Electric vehicles are equipped with batteries that serve as their power source. The batteries are housed in a container called a battery box. For example, Patent Document 1 describes a vehicle battery case comprising a battery tray having a bottom wall on which the battery is placed and a circumferential side wall surrounding the bottom wall, and a battery cover that covers the battery tray, wherein the battery tray has a groove formed over the entire circumference of the upper surface of the circumferential side wall, a wall erected at least on the outermost opening edge of the groove, and a sealing member formed to be continuous over the entire circumference of the groove and housed in the groove, and the battery tray and the battery cover are fixed together with the sealing member assembled in the groove, so that the sealing member is sandwiched between the battery tray and the battery cover.

[0003] Patent Document 2 describes an electrical component case in the shape of a box for housing electrical components, comprising: a tray member that supports the electrical components and has a first flange portion around its circumference; a cover member that has a second flange portion around its circumference that overlaps with the first flange portion and is positioned on the tray member to cover the electrical components; an annular gasket member supported by a clip member on one of the flange portions of the first and second flange portions; and a fixing member that fixes the first and second flange portions to overlap, wherein the other flange portion that abuts the annular gasket member has a stepped portion that moves away from the one flange portion to accommodate the annular gasket member.

[0004] Patent Document 3 discloses a battery case for accommodating a driving battery of an electric vehicle, comprising: a tray member that supports the battery; a cover member that is stacked on the tray member and fixed to the tray member; and a gasket interposed between the tray member and the cover member, wherein the cover member has a positioning pin protrudingly provided near the gasket along a joining direction of the cover member and the tray member, and the tray member has a positioning hole drilled along the joining direction for insertion of the positioning pin.

[0005] Japanese Patent Application Laid-Open No. 2011-194982, Japanese Patent Application Laid-Open No. 2014-175123, Japanese Patent Application Laid-Open No. 2012-124131

[0006] In a storage container such as a battery box, in order to fasten a container body such as a battery tray and a lid such as a battery cover, flanges are provided on both of them, and a flange portion where the two are fastened together using a fastening member at the flanges is provided. However, since the flange portion has a flat plate shape, sufficient rigidity cannot be secured.

[0007] Therefore, an object of the present invention is to increase the rigidity of a storage container.

[0008] As a result of intensive studies, the present inventors have found that the above problems can be solved by the means described below, and have arrived at the present invention.

[0009] [1] A storage container comprising: a container having a bottom and a wall portion erected from the outer periphery of the bottom; a lid disposed on the upper part of the wall portion, having a top plate, a first flange provided below the top plate and on the outer periphery, and a connecting portion connecting the top plate and the first flange; and fastening members for fastening the first flange and the container, wherein the lid is made of metal, fiber-reinforced plastic, or both; the first flange has an annular projection protruding from its upper surface; and the projection has a wave shape that displaces in the inward and outward directions of the storage container according to the circumferential position of the first flange. [2] The storage container according to [1], further comprising a plurality of fastening members for fastening the first flange and the container, wherein the fastening members are provided at positions in the circumferential direction of the first flange where the projection is displaced inward toward the storage container. [3] The storage container according to [1] or [2], wherein the projection is displaced outward toward the storage container at two or more locations between two fastening members. [4] The storage container according to any one of [1] to [3], wherein an annular groove is provided on the lower surface of the first flange at a position corresponding to the protrusion, and a sealing material is further provided in the groove to seal the space between the first flange and the wall portion. [5] The storage container according to any one of [1] to [4], wherein a projection is provided at a position displaced inward from the storage container of the protrusion, projecting toward the connection portion. [6] The storage container according to [5], wherein an annular groove is provided on the lower surface of the first flange at a position corresponding to the protrusion, and a sealing material is further provided in the groove to seal the space between the first flange and the wall portion, and a recess is provided on the lower surface of the first flange at a position corresponding to the projection, continuous with the groove. [7] The storage container according to any one of [1] to [6], wherein a convex portion is provided on the upper surface of the first flange between a position displaced inward from the storage container of the protrusion and the connection portion. [8] The storage container according to any one of [1] to [6], wherein a protrusion is provided on the upper surface of the first flange between a position where the protrusion is displaced outward from the storage container and the connecting portion.[9] The storage container according to [7] or [8], wherein the lower surface of the first flange is provided with a recess at a position corresponding to the protrusion.

[10] The storage container according to any one of [1] to [9], wherein the lid is made of fiber-reinforced plastic including discontinuous reinforcing fibers and thermoplastic.

[0010] According to the present invention, the rigidity of the storage container can be increased.

[0011] Perspective view of battery box 10A. Exploded perspective view of battery box 10A. Perspective view of battery cover 30A viewed from below. Cross section viewed along the line IV-IV in Figure 1. Perspective view of battery box 10B. Perspective view of battery cover 30B viewed from below. Perspective view of battery box 10C. Perspective view of battery cover 30C viewed from below.

[0012] Embodiments of the present invention will be described below, but the present invention is not limited thereto. [First Embodiment] Figure 1 is a perspective view of a battery box 10A according to the first embodiment of the storage container of the present invention, and Figure 2 is an exploded perspective view of the battery box 10A. The battery box 10A of the embodiment of the present disclosure comprises a battery tray 20 and a battery cover 30A. A battery 1 is housed inside the battery box 10A. Ventilation holes may be provided in the battery box 10A to help cool the battery 1. A cooling fan may also be incorporated into the battery box 10A.

[0013] The battery tray 20 is an example of a container in the storage container of the present invention. The battery tray 20 stably and securely holds the battery 1, which functions as a power source for an automobile, and protects the battery 1 from vibration and shock. There are no particular limitations on the material of the battery tray 20; it may be made of metal such as iron or aluminum, or it may be made of fiber-reinforced plastic.

[0014] The battery tray 20 is designed to match the shape of the battery 1 and has a bottom portion 21 and a wall portion 22 that is erected from the outer circumference of the bottom portion 21. The battery tray 20 may be equipped with mounting fixtures and fixing devices to facilitate the installation and removal of the battery 1. A second flange 23 is provided at the upper end of the wall portion 22. The second flange 23 is provided in an annular shape so as to protrude horizontally outward from the upper end of the wall portion 22. The second flange 23 constitutes the upper surface of the wall portion 22. The second flange 23 faces the first flange 33 of the battery cover 30A, which will be described later, and is in close contact with the sealing material 40 provided on the first flange 33. The second flange 23 is also provided with an insertion hole 24. The battery tray 20 having the bottom portion 21, wall portion 22 and second flange 23 may be integrally molded, or the bottom portion 21, wall portion 22 and second flange 23 may be made as separate parts and then assembled into a single battery tray 20.

[0015] The battery cover 30A is positioned on top of the battery tray 20. The battery cover 30A is an example of a lid in the storage container of the present invention.

[0016] The battery cover 30A is made of metal, fiber-reinforced plastic, or both. Examples of a battery cover 30A made of both metal and fiber-reinforced plastic include a laminate of metal and fiber-reinforced plastic, or a cover in which a metal portion and a fiber-reinforced plastic portion are joined together. Examples of metals include one or more selected from the group consisting of iron, aluminum, magnesium, and titanium. Regarding the metals listed above, for example, iron includes not only pure iron but also its alloys. The fiber-reinforced plastic may be either thermoplastic or thermosetting plastic. Examples of thermosetting plastics include epoxy resin, vinyl ester resin, unsaturated polyester resin, diallyl phthalate resin, phenolic resin, bismaleimide resin, cyanate resin, benzoxazine resin, or dicyclopentadiene resin. Thermoplastics typically used have a softening point (melting point for crystalline thermoplastics, and glass transition temperature for amorphous thermoplastics) in the range of 180°C to 350°C. Examples include polyolefin resins, polystyrene resins, thermoplastic polyamide resins, polyester resins, polyacetal resins (polyoxymethylene resins), polycarbonate resins, (meth)acrylic resins, polyarylate resins, polyphenylene ether resins, polyimide resins, polyethernitrile resins, phenoxy resins, polyphenylene sulfide resins, polysulfone resins, polyketone resins, polyetherketone resins, thermoplastic urethane resins, fluororesins, and thermoplastic polybenzimidazole resins. Reinforcing fibers in fiber-reinforced plastics include one or more selected from the group consisting of glass fibers, carbon fibers, aramid fibers, boron fibers, and basalt fibers. Examples of reinforcing fiber forms include woven fabrics, knitted fabrics, nonwoven fabrics, random mats, knits, braids, or multiple reinforcing fibers arranged in one direction. Examples of carbon fibers include polyacrylonitrile (PAN) carbon fibers, petroleum pitch carbon fibers, coal pitch carbon fibers, rayon carbon fibers, cellulose carbon fibers, lignin carbon fibers, phenolic carbon fibers, or vapor-grown carbon fibers.Among the above combinations, fiber-reinforced plastics consisting of discontinuous reinforcing fibers and thermoplastics are particularly preferred. Specifically, various shapes and materials can be used, such as those described in International Publication No. 2024 / 237241, U.S. Patent Application Publication No. 2016 / 0356334, or International Publication No. 2020 / 129227. Carbon fibers or glass fibers are particularly preferred as discontinuous reinforcing fibers.

[0017] When discontinuous reinforcing fibers are included in fiber-reinforced plastic, their state of existence is not particularly limited; for example, they may be arranged in one direction or randomly. From the viewpoint of shape rigidity and strength uniformity of the impact-absorbing member, it is preferable that the reinforcing fibers are arranged in a two-dimensional random arrangement, where the long axis direction of the reinforcing fibers is randomly aligned in the in-plane direction of the fiber-reinforced plastic. Here, the fact that the discontinuous reinforcing fibers in the fiber-reinforced plastic are in a two-dimensional random arrangement can be confirmed, for example, by performing a tensile test based on an arbitrary direction of the fiber-reinforced plastic and a direction perpendicular thereto, measuring the tensile modulus in each direction, and then measuring the ratio (Eδ) obtained by dividing the larger of the measured tensile modulus values ​​by the smaller one. If the ratio of tensile moduli is less than 2, the reinforcing fibers can be evaluated as being in a two-dimensional random arrangement, and if the ratio of tensile moduli is less than 1.3, it can be evaluated as an excellent two-dimensional random arrangement.

[0018] The following describes an embodiment of the battery cover 30A. The battery cover 30A can be formed by press molding. In the case of a battery cover 30A made of fiber-reinforced plastic containing discontinuous reinforcing fibers and thermoplastic, molding methods such as hot press molding and cold press molding can be used as press molding.

[0019] [Cold Press Molding] When press molding fiber-reinforced plastics, cold press molding is preferred. In the cold press molding method, for example, fiber-reinforced plastic heated to a first predetermined temperature is placed into a mold set to a second predetermined temperature, and then pressurized and cooled. Specifically, if the thermoplastic contained in the fiber-reinforced plastic is crystalline, the first predetermined temperature is above the melting point, and the second predetermined temperature is below the melting point. If the thermoplastic is amorphous, the first predetermined temperature is above the glass transition temperature, and the second predetermined temperature is below the glass transition temperature. That is, the cold press method includes at least the following steps A-1) to A-2).

[0020] Step A-1) A step of heating the thermoplastic plastic to a temperature above its melting point and below its decomposition temperature if it is crystalline, or above its glass transition temperature and below its decomposition temperature if it is amorphous. Step A-2) A step of placing the fiber-reinforced plastic heated in Step A-1) into a mold that is temperature-controlled to below its melting point if it is crystalline, or below its glass transition temperature if it is amorphous, and applying pressure. By performing these steps, the molding of the fiber-reinforced plastic can be completed.

[0021] Each of the above steps must be performed in the order specified above, but other steps may be included between each step. Other steps include, for example, a forming step performed before step A-2) in which a different forming die from the one used in step A-2) is used to pre-form the shape of the cavity of the forming die.

[0022] [Hot Press Molding] The hot press molding method involves, for example, placing fiber-reinforced plastic into a mold, increasing the temperature of the mold to a first predetermined temperature while applying pressure, and then cooling the mold to a second predetermined temperature. Specifically, if the thermoplastic constituting the fiber-reinforced plastic is crystalline, the first predetermined temperature is above the melting point, and the second predetermined temperature is below the melting point. If the thermoplastic contained in the fiber-reinforced plastic is amorphous, the first predetermined temperature is above the glass transition temperature, and the second predetermined temperature is below the glass transition temperature. Hot press molding preferably includes at least the following steps B-1) to B-4).

[0023] B-1) A step of placing fiber-reinforced plastic into a mold. B-2) A step of heating and pressurizing the mold to a temperature above the melting point of the thermoplastic plastic but below its decomposition temperature if the thermoplastic plastic is crystalline, or to a temperature above the glass transition temperature of the thermoplastic plastic but below its decomposition temperature if the thermoplastic plastic is amorphous (first pressing step). B-3) A step of pressurizing the mold in one or more stages, such that the pressure in the final stage is between 1.2 and 100 times the pressure in the first pressing step (second pressing step). B-4) A step of adjusting the mold temperature to below the melting point if the thermoplastic plastic is crystalline, or below the glass transition temperature if the thermoplastic plastic is amorphous. By performing these steps, the battery cover 30A can be manufactured.

[0024] [Common points for cold press molding and hot press molding] Steps A-2) and B-3) are steps to obtain a battery cover 30A of the desired shape by applying pressure to fiber-reinforced plastic. There are no particular limitations on the molding pressure at this time, but it is preferable to keep it as low as possible within the range in which the desired molded shape can be obtained. Specifically, it is preferable to have a molding pressure of less than 30 MPa relative to the projected area of ​​the mold cavity, more preferably 20 MPa or less, and even more preferably 10 MPa or less. When the molding pressure is less than 30 MPa, it is preferable because it does not require capital investment or maintenance costs for the press machine. In addition, various steps may be inserted between the above steps during press molding, for example, vacuum press molding, which is press molding while under vacuum, may be used. When the battery cover 30A consists of both metal and fiber-reinforced plastic, for example, metal parts (insert parts) may be placed in the mold in advance, and then the fiber-reinforced plastic may be put into the mold and press molded.

[0025] The battery cover 30A has a top plate 31, a first flange 33 provided below the top plate 31 and on the outer circumference, and a connecting portion 32 that connects the top plate 31 and the first flange 33. The first flange 33 is provided on the outer circumference of the battery cover 30A. The lower surface of the first flange 33 is the region facing the second flange 23 of the battery tray 20. The first flange 33 is provided with an insertion hole 34 into which the shaft portion 2S of a bolt 2 (fastening member) is inserted. The shaft portion 2S of the bolt 2, inserted from above the insertion hole 34, is inserted into the insertion hole 24 of the second flange 23 and fastened with a nut 3 (see Figure 4) below the second flange 23, thereby fixing the battery cover 30A to the battery tray 20. The insertion hole 34 is provided in the circumferential direction of the first flange 33, at a position where a protrusion 35, described later, is displaced toward the inside of the battery box 10A. Therefore, the bolt 2 is also installed in a position where the protrusion 35 is displaced inward from the battery box 10A.

[0026] An annular projection 35 is provided on the upper surface of the first flange 33, on the inside of the battery box 10A beyond the insertion hole 34. As shown in Figures 1 and 2, the projection 35 extends circumferentially around the battery cover 30A on the first flange 33, displacing in the inward and outward directions of the battery box 10A. In the first embodiment, the projection 35 has a shape that displaces in the inward and outward directions of the battery box 10A, bending at approximately 90°, such that the distance to the connection portion 32 is rectangular wave-shaped. As shown in Figure 2, the projection 35 is displaced inward towards the battery box 10A at the position where the insertion hole 34 is provided in the circumferential direction of the first flange 33, and displaced outward towards the battery box 10A at other positions in the circumferential direction of the first flange 33 (positions between the two insertion holes 34), forming a zigzag ring. The projection 35 may also be provided with a projection 35A that protrudes toward the connection portion 32 at a position displaced inward towards the battery box 10A beyond the insertion hole 34.

[0027] Furthermore, an independent protrusion 36A may be provided on the upper surface of the first flange 33 between the protrusion 35 and the connecting portion 32, where the protrusion is displaced outward from the battery box 10A. Here, "independent" means provided at a position away from the protrusion 35 and the connecting portion 32. In addition, an independent protrusion 36B may be provided on the upper surface of the first flange 33 between the protrusion 35 and the connecting portion 32, where the protrusion is displaced inward from the battery box 10A than the insertion hole 34.

[0028] Figure 3 is a perspective view of the battery cover 30A from below. As shown in Figure 3, an annular groove 41A is provided on the lower surface of the first flange 33, inside the battery box 10A beyond the insertion hole 34. The groove 41A has a shape corresponding to the projection 35, and the groove 41A is formed on the back side of the projection 35. As shown in Figure 3, the groove 41A bends at approximately 90°, so that the distance from the connection portion 32 is rectangular wave-shaped. The groove 41A is displaced inward towards the battery box 10A at the position where the insertion hole 34 is provided in the circumferential direction of the first flange 33, and at other positions in the circumferential direction of the first flange 33 (positions between the two insertion holes 34), it is displaced outward towards the battery box 10A, forming a zigzag ring. Furthermore, if a projection 35A is provided on the ridge 35 at a position displaced inward from the insertion hole 34 towards the battery box 10A, a recess 42 continuous with the groove 41A may also be provided on the groove 41A at a position displaced inward from the insertion hole 34 towards the battery box 10A towards the battery box 10A, corresponding to the projection 35A.

[0029] Furthermore, if a protrusion 36A is provided on the upper surface of the first flange 33, an independent recess 46A may be provided at a position corresponding to the protrusion 36A on the lower surface of the first flange 33. In addition, if a protrusion 36B is provided on the upper surface of the first flange 33, an independent recess 46B may be provided at a position corresponding to the protrusion 36B on the lower surface of the first flange 33.

[0030] Figure 4 is a cross-sectional view taken along the line IV-IV in Figure 1. As shown in Figure 4, a sealing material 40 is provided inside the groove 41A. Any sealing material can be used as the sealing material 40. For example, silicone-based sealing materials, synthetic rubber-based sealing materials, polyurethane-based sealing materials, epoxy resin-based sealing materials, etc., can be used. It is preferable that the sealing material is in liquid form. If the sealing material is in liquid form, an annular sealing material 40 can be formed by applying the sealing material into the annular groove 41A.

[0031] As shown in Figure 4, when the first flange 33 and the second flange 23 are fastened together by bolts 2 and nuts 3, the sealing material 40 is provided to be in close contact with the second flange 23 and subjected to pressure between the first flange 33 and the second flange 23. By sealing the gap between the second flange 23 and the first flange 33, the sealing material 40 can prevent water and air from entering the inside of the battery box 10A. Furthermore, even if gas is generated from the battery 1 or the like inside the battery box 10A, it can prevent the gas from leaking out of the battery box 10A.

[0032] In the first embodiment, the rigidity of the first flange 33 can be increased by providing a protrusion 35 on the first flange 33. Furthermore, the rigidity of the first flange 33 can be further increased by providing projections 35A, protrusions 36A, and protrusions 36B. As a result, the spacing between the bolts 2 and nuts 3 can be increased, and the number of bolts 2 and nuts 3 required to fasten the first flange 33 and the second flange 23 can be reduced. In addition, the rigidity of the battery box 10A, to which the first flange 33 and the second flange 23 are fastened with bolts 2 and nuts 3, can be increased.

[0033] [Second Embodiment] Figure 5 is a perspective view of a battery box 10B according to a second embodiment of the storage container of the present invention. Components similar to those of the battery box 10A of the first embodiment are denoted by the same reference numerals and their descriptions are omitted.

[0034] In the second embodiment, the shape of the projection 35B provided on the upper surface of the first flange 33 differs from that of the projection 35 in the first embodiment. The projection 35 in the first embodiment is bent at approximately 90° and displaced in the inward and outward directions of the battery box 10A such that the distance to the connection portion 32 is rectangular wave-shaped. In contrast, the projection 35B in the second embodiment is displaced in the inward and outward directions of the battery box 10B on the upper surface of the first flange 33 and has a bent shape such that the distance to the connection portion 32 is triangular wave-shaped. In the second embodiment as well, the projection 35B is displaced inward towards the battery box 10A at the position where the insertion hole 34 is provided in the circumferential direction of the first flange 33, and displaced outward towards the battery box 10A at other positions in the circumferential direction of the first flange 33 (positions between the two insertion holes 34) to form a zigzag ring.

[0035] Figure 6 is a perspective view of the battery cover 30B of the second embodiment, viewed from below. As shown in Figure 6, an annular groove 41B is provided on the lower surface of the first flange 33, inside the battery box 10B beyond the insertion hole 34. The groove 41B has a shape corresponding to the projection 35B, and the groove 41B is formed on the back side of the projection 35B. As shown in Figure 6, the groove 41B is displaced in the inward and outward directions of the battery box 10B on the upper surface of the first flange 33, and has a bent shape such that the distance from the connection portion 32 is triangular wave-shaped. The groove 41B is displaced inward towards the battery box 10B at the position where the insertion hole 34 is provided in the circumferential direction of the first flange 33, and at other positions in the circumferential direction of the first flange 33 (positions between the two insertion holes 34), it is displaced outward towards the battery box 10B, forming a zigzag ring.

[0036] In the second embodiment as well, a projection similar to that in the first embodiment may be provided on the ridge 35B at a position displaced inward from the insertion hole 34 towards the battery box 10B. In this case, a recess may also be provided on the groove 41B at a position corresponding to the projection, at a position displaced inward from the insertion hole 34 towards the battery box 10B.

[0037] Furthermore, similar to the first embodiment, protrusions 36A and 36B may be provided on the upper surface of the first flange 33, and independent recesses 46A and 46B may be provided on the lower surface of the first flange 33 at positions corresponding to the protrusions 36A and 36B.

[0038] [Third Embodiment] Figure 7 is a perspective view of a battery box 10C according to a third embodiment of the storage container of the present invention. Components similar to those in the battery box 10B of the second embodiment are denoted by the same reference numerals and their descriptions are omitted.

[0039] In the third embodiment, the shape of the protrusion 35C provided on the upper surface of the first flange 33 is similar to that of the protrusion 35B in the second embodiment, being displaced in the inward and outward direction of the battery box 10C on the upper surface of the first flange 33 and having a bent shape such that the distance from the connection portion 32 is triangular wave-shaped. In the second embodiment, the protrusion 35B was displaced inward towards the battery box 10B at the position where the insertion hole 34 is provided in the circumferential direction of the first flange 33. In contrast, in the third embodiment, in addition to the position where the insertion hole 34 is provided, the protrusion 35C is also displaced inward towards the battery box 10C at a position midway between two adjacent insertion holes.

[0040] Figure 8 is a perspective view of the battery cover 30C of the third embodiment, viewed from below. As shown in Figure 8, an annular groove 41C is provided on the lower surface of the first flange 33, inside the battery box 10C beyond the insertion hole 34. The groove 41C has a shape corresponding to the projection 35C, and the groove 41C is formed on the back side of the projection 35C. As shown in Figure 8, the groove 41C is displaced in the inward and outward directions of the battery box 10C on the upper surface of the first flange 33, and has a bent shape such that the distance from the connection portion 32 is triangular wave-shaped. At the position where the insertion hole 34 is provided in the circumferential direction of the first flange 33, and at the intermediate position between two adjacent insertion holes, the groove 41C is displaced inward towards the battery box 10C, and at other positions (two locations between the two insertion holes 34) it is displaced outward towards the battery box 10C, forming a zigzag ring.

[0041] Furthermore, in the present embodiment, a projection similar to that in the first embodiment may also be provided at a position of the protrusion 35C displaced inward of the battery box 10C. In this case, a recess may also be provided in the groove 41C at a position displaced inward of the battery box 10C, at a position corresponding to the projection.

[0042] Further, similarly to the first embodiment, convex portions 36A and 36B may be provided on the upper surface of the first flange 33, and independent concave portions 46A and 46B may be provided at positions corresponding to the convex portions 36A and 36B on the lower surface of the first flange 33.

[0043] In the above, the present invention has been described with reference to embodiments and modified examples, but the present invention is not limited thereto. In the first embodiment, the protrusion 35 is shaped to be displaced inward and outward of the battery box 10A such that the distance between the protrusion 35 and the connecting portion 32 forms a rectangular wave shape. In the second embodiment, the protrusion 35B is shaped to be displaced inward and outward of the battery box 10B such that the distance between the protrusion 35B and the connecting portion 32 forms a triangular wave shape. However, for example, the protrusion may be shaped to be displaced inward and outward of the battery box such that the distance between the protrusion and the connecting portion forms a sine wave shape.

[0044] Further, the protrusion 35 of the first embodiment and the protrusion 35B of the second embodiment are displaced outward of the battery box at one position between two bolts 2, and the protrusion 35C of the third embodiment is displaced outward of the battery box at two positions between two bolts 2. However, a protrusion displaced outward of the battery box at three or more positions between two bolts 2 may also be provided.

[0045] In the above embodiments and modified examples, a battery box that houses a battery functioning as a power source for an automobile is taken as an example, but the present invention is not limited thereto. For example, the present invention may also be applied to a storage container that houses a fuel cell.

[0046] In the following cases, a load of 100 kPa was applied between two bolts, and the displacement of the first flange was measured. The results are shown in Table 1.

[0047] As shown in Table 1, in Examples 1 to 3, where protrusions or the like are provided on the first flange and the bolt spacing is 100 mm, the displacement is smaller than in Comparative Example 1, where the bolt spacing is 100 mm in a flat first flange without protrusions or the like. This shows that the rigidity of the first flange can be increased by providing protrusions or the like on the first flange. Furthermore, the displacement in Examples 1 to 3 with a bolt spacing of 100 mm is about the same as that in Comparative Example 2, where the bolt spacing is 80 mm in a flat first flange. Therefore, by providing protrusions or the like on the first flange, the bolt spacing can be increased, and it can be seen that the number of bolts can be reduced by 20% while maintaining the rigidity of the first flange when comparing the above examples with Comparative Example 2. This effect is particularly advantageous when the storage container is used as a battery box for electric vehicles. Electric vehicle batteries pose a risk of emitting large amounts of flammable gas and flames if thermal runaway occurs. For this reason, the flange portion of the battery box that houses the battery requires an extremely robust sealing mechanism that exhibits sufficient rigidity, and is fastened with numerous bolts. Therefore, reducing the number of bolts used by 20% would result in a significant reduction in material costs for bolts and other components, as well as assembly labor.

Claims

1. A storage container comprising: a container having a bottom and a wall portion erected from the outer periphery of the bottom; a lid positioned on the upper part of the wall portion, having a top plate, a first flange provided below the top plate and on the outer periphery, and a connecting portion connecting the top plate and the first flange; and a fastening member for fastening the first flange and the container, wherein the lid is made of metal, fiber-reinforced plastic, or both; the first flange has an annular projection protruding from its upper surface; and the projection has a wave shape that displaces in the inward and outward directions of the storage container according to the circumferential position of the first flange.

2. The storage container according to claim 1, having a plurality of fastening members for fastening the first flange and the container, wherein the fastening members are provided in the circumferential direction of the first flange at a position where the protrusion is displaced toward the inside of the storage container.

3. The storage container according to claim 2, wherein the protrusion is displaced outward from the storage container at one or more locations between the two fastening members.

4. The storage container according to claim 1, wherein an annular groove is provided on the lower surface of the first flange at a position corresponding to the protrusion, and a sealing material is further provided in the groove to seal the space between the first flange and the wall portion.

5. The storage container according to claim 1, wherein a projection is provided at a position where the protrusion is displaced inward from the storage container, projecting toward the connecting portion.

6. The storage container according to claim 5, wherein an annular groove is provided on the lower surface of the first flange at a position corresponding to the protrusion, a sealing material is further provided in the groove to seal the space between the first flange and the wall, and a recess is provided on the lower surface of the first flange at a position corresponding to the projection and continuous with the groove.

7. The storage container according to claim 1, wherein a protrusion is provided on the upper surface of the first flange between the position of the protrusion displaced in the inward direction of the storage container and the connecting portion.

8. The storage container according to claim 1, wherein a protrusion is provided on the upper surface of the first flange between the position of the protrusion displaced outward from the storage container and the connecting portion.

9. The storage container according to claim 7 or 8, wherein a recess is provided on the lower surface of the first flange at a position corresponding to the protrusion.

10. The storage container according to claim 1, wherein the lid is made of fiber-reinforced plastic containing discontinuous reinforcing fibers and thermoplastic.

Images