Storage container

Abstract

The present invention enhances the rigidity of a storage container.　This storage container (10) comprises: a container (20) having a bottom part (21) and a wall part (22) erected from an outer peripheral portion of the bottom part (21); a lid (30) having a top plate (31), a first flange (33) provided below the top plate (31) and on an outer peripheral portion, and a connection part (32) connecting the top plate (31) and the first flange (33), the lid being disposed on an upper portion of the wall part (22); and a fastening member (2) fastening together the first flange (33) and the container (20). The lid (30) is made of metal, fiber-reinforced plastic, or both thereof, and the connection part (32) has a recessed portion (35) recessed toward the inside of the storage container (10).

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 drive battery of an electric vehicle, comprising: a tray member that supports the battery; a cover member 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 bored along the joining direction into which the positioning pin is inserted. A battery case characterized by the above is described.

[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 obtained by fastening the two using a fastening member at the flanges is provided. However, since the flange portion has a flat plate shape, sufficient rigidity cannot be ensured.

[0007] Accordingly, 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 problem 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 a fastening member for fastening the first flange and the container, wherein the lid is made of metal, fiber-reinforced plastic, or both, and the connecting portion has a recess recessed on the inside of the storage container. [2] The storage container according to [1], wherein the container has a second flange protruding from the upper end of the wall portion to the outside of the storage container, and a sealing material is further provided to seal the space between the first flange and the second flange, and the fastening member has a shaft portion that penetrates the first flange and the second flange, and a head portion provided at one end of the shaft portion and having an outer diameter larger than the outer diameter of the shaft portion, and the sealing material is provided inside the storage container below the shaft portion, and the head portion and the sealing material are in close proximity. [3] The storage container according to [2], wherein the distance from the sealing material to the head is within three times the outer diameter of the head. [4] The storage container according to [2], wherein the lower surface of the connection portion is provided with an annular groove in which the sealing material is provided, and the first flange and the second flange are fastened together by the fastening member so that the sealing material and the second flange are in close contact. [5] The storage container according to [4], wherein the lower surface of the connection portion has an annular projection that is inside the storage container from the first flange, and the groove is provided between the first flange and the projection. [6] The storage container according to [5], wherein the projection protrudes downward from the lower surface of the first flange, and the lower end of the projection is positioned inside the storage container from the wall portion. [7] The storage container according to [1], wherein the lid is made of fiber-reinforced plastic including discontinuous reinforcing fibers and thermoplastic plastic.

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

[0011] Perspective view of battery box 10. Exploded perspective view of battery box 10. Perspective view of battery cover 30 viewed from below. Cross-sectional view taken along the line IV-IV in Figure 1. Perspective view of battery cover 30B viewed from below. Cross-sectional view similar to Figure 4, showing the battery cover 30B fastened to the battery tray 20.

[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 10 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 10. The battery box 10 of the embodiment of the present disclosure comprises a battery tray 20 and a battery cover 30. A battery 1 is housed inside the battery box 10. Ventilation holes may be provided in the battery box 10 to help cool the battery 1. A cooling fan may also be incorporated into the battery box 10.

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

[0016] The battery cover 30 is made of metal, fiber-reinforced plastic, or both. Examples of a battery cover 30 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 example of the battery cover 30. The battery cover 30 can be molded by press molding. In the case of a battery cover 30 made of fiber-reinforced plastic containing discontinuous reinforcing fibers and thermoplastic plastic, molding methods such as hot press molding and cold press molding can be used for 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 30 can be manufactured.

[0024] [Common points for cold press molding and hot press molding] Steps A-2) and B-3) are steps in which pressure is applied to fiber-reinforced plastic to obtain a battery cover 30 of the desired shape. 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.

[0025] Furthermore, if the battery cover 30 is made of both metal and fiber-reinforced plastic, for example, metal parts (insert parts) may be placed in the mold beforehand, and then the fiber-reinforced plastic may be introduced into the mold and press-molded.

[0026] The battery cover 30 has a top plate 31, a first flange 33 provided below the top plate 31 and on the outer periphery, 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 periphery of the battery cover 30. 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 30 to the battery tray 20.

[0027] Furthermore, the connection portion 32 is provided with a recessed area 35 that is recessed into the inside of the battery box 10. Preferably, the recessed area 35 is provided near the insertion hole 34. When the recessed area 35 is provided near the insertion hole 34, the head 2H of the bolt 2 is positioned inside the recessed area 35 when the bolt 2 fastens the first flange 33 and the second flange 23.

[0028] Figure 3 is a perspective view of the battery cover 30 from below. Figure 4 is a cross-sectional view taken along the line IV-IV in Figure 1. As shown in Figures 3 and 4, an annular projection 36 is provided on the lower surface of the battery cover 30 along the inner circumferential surface of the connection portion 32, and an annular groove 41 is provided between the first flange 33 and the projection 36. A sealing material 40 is provided in an annular shape within the groove 41. Since the first flange 33 has an insertion hole 34 and the groove 41 is provided inside the battery box 10 beyond the first flange 33, the sealing material 40 is provided inside the battery box 10 beyond the shaft portion 2S of the bolt 2.

[0029] 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 prevents water and air from entering the battery box 10. Furthermore, even if gas is generated from the battery 1 or the like inside the battery box 10, it is possible to prevent the gas from leaking out of the battery box 10.

[0030] 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. The sealing material is preferably 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 41.

[0031] In this embodiment, by providing the recess 35, the connecting portion 32 is no longer simply a flat plate shape, and a substantially semi-cylindrical shape is formed by the recess 35 and the first flange 33. As a result, the rigidity of the first flange 33 and the battery cover 30 including the first flange 33 can be increased in the portion where the recess 35 is formed. Furthermore, the rigidity of the battery box 10, which fastens the first flange 33 and the second flange 23 with bolts 2 and nuts 3, can be increased. Therefore, 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.

[0032] Furthermore, if a recess 35 is provided in the connection portion 32 near the insertion hole 34, the head 2H of the bolt 2 can be positioned further inside the battery box 10 than the outer surface of the connection portion 32 where the recess 35 is not provided. By providing the recess 35 near the insertion hole 34, the length (length in the left-right direction in Figure 4) necessary to position the head 2H of the bolt 2 on the upper surface of the first flange 33 can be secured. As a result, the length of the first flange 33 that protrudes from the connection portion 32 to the outside of the battery box 10 can be shortened. Consequently, the volume of the battery box 10 can be increased relative to the space in which it is housed.

[0033] Furthermore, by providing a recess 35 near the insertion hole 34, the head 2H of the bolt 2 can be positioned close to the sealing material 40. Specifically, it is preferable that the distance from the sealing material 40 to the head 2H be within three times the outer diameter of the head 2H. For example, the distance from the sealing material 40 to the head 2H can be within 5 mm, and even within 3 mm. By bringing the sealing material 40 and the head 2H close together, the fastening force from the bolt 2 can be more easily applied to the sealing material 40. As a result, the sealing material 40 can be elastically deformed and brought into close contact with the second flange 23.

[0034] <Modified Version> Figure 5 is a perspective view of the battery cover 30B according to a modified version of this embodiment, viewed from below. Figure 6 is a cross-sectional view similar to Figure 4, showing the battery cover 30B fastened to the battery tray 20. Note that components similar to those in the above embodiment are denoted by the same reference numerals and their descriptions are omitted. In this modified version, an annular projection 36B provided along the inner circumferential surface of the connection portion 32 protrudes to below the first flange 33. As shown in Figure 6, with the first flange 33 and the second flange 23 fastened together by bolts 2, the lower end of the projection 36B is positioned below the upper end of the wall portion 22 and inside the battery box 10. It is preferable that the outer surface of the battery box 10 at the lower end of the projection 36B and the inner surface of the battery box 10 on the wall portion 22 are in contact.

[0035] In this modified example, since the lower end of the protrusion 36B is positioned below the upper end of the wall portion 22 and inside the battery box 10, the sealant 40 can be protected by the protrusion 36B even if a fire occurs inside the battery box 10. In particular, when the outer surface of the lower end of the protrusion 36B is in contact with the inner surface of the wall portion 22, the sealant 40 can be protected from the hot gas inside the battery box 10. For this reason, a material with lower heat resistance can be used as the sealant 40. Depending on the material of the sealant 40, there is a problem that it is difficult to peel off from the battery cover 30B, making it difficult to recycle the battery cover 30B made of fiber-reinforced plastic. In this modified example, since a material with lower heat resistance can be used as the sealant 40, it is possible to use a sealant 40 that is easier to peel off and promote the recycling of the battery cover 30B. For example, a sealant 40 made of an elastic material such as an O-ring may be used. Examples of elastic materials that can be used for O-rings include nitrile rubber, silicone rubber, and fluororubber.

[0036] The present invention has been described above using embodiments and modifications, but the present invention is not limited thereto. In the above embodiments and modifications, a battery box housing a battery that functions as a power source for an automobile was given as an example, but the present invention is not limited thereto, and for example, the present invention may be applied to a housing container for a fuel cell.

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, and the connecting portion has a recessed portion in the inner side of the storage container.

2. The storage container according to claim 1, wherein the container has a second flange protruding from the upper end of the wall portion to the outside of the storage container, and a sealing material is further provided to seal the space between the first flange and the second flange, and the fastening member has a shaft portion that penetrates the first flange and the second flange, and a head portion provided at one end of the shaft portion and having an outer diameter larger than the outer diameter of the shaft portion, and the sealing material is provided inside the storage container from the shaft portion, and the head portion and the sealing material are in close proximity.

3. The storage container according to claim 2, wherein the distance from the sealing material to the head is within three times the outer diameter of the head.

4. The storage container according to claim 2, wherein an annular groove is provided on the lower surface of the connecting portion, and the first flange and the second flange are fastened together by the fastening member, so that the sealing material and the second flange are in close contact.

5. The storage container according to claim 4, wherein the lower surface of the connecting portion has an annular projection that is inside the storage container beyond the first flange, and the groove is provided between the first flange and the projection.

6. The storage container according to claim 5, wherein the projection protrudes below the lower surface of the first flange, and the lower end of the projection is positioned inside the storage container relative to the wall portion.

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

Images