Battery case structure

Abstract

To provide a battery case structure which more effectively buffers a force acting on a battery pack from below.SOLUTION: A battery case structure to be mounted on a vehicle includes a battery case 2 disposed above a road surface interference panel 8, and a pair of case supports 4 each including a bottom support portion 3 and having a top portion 4t facing the battery case 2, a bottom portion 4b facing the road surface interference panel 8, and a wall portion 4w connecting the top portion 4t and the bottom portion 4b. And a shock-absorbing portion 5 disposed between the pair of case support bodies 4, wherein the top portion side 4t of each of the case support bodies 4 extends toward the other case support body 4, the shock-absorbing portion 5 is interposed between a lower surface of the top portion side 4t and an upper surface of the road surface interfering panel 8, and in the shock-absorbing portion 5, an area of a shock-absorbing bottom surface side 5b facing the road surface interfering panel 8 is larger than an area of a shock-absorbing top surface side 4t facing the top portion side 5t.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a battery case structure to be mounted on a vehicle. [Background technology]

[0002] In recent years, many vehicles have been equipped with one or more unit cells. Examples of such unit cells include secondary batteries that are used as driving batteries and can be repeatedly charged and discharged.

[0003] In recent years, it has become common for battery-powered electric vehicles, also known as BEVs, to mount one or more cells housed in a battery case (sometimes referred to as a battery pack in this specification as necessary) under the vehicle (see Patent Document 1). Mounting the battery pack under the vehicle makes it possible to sufficiently shorten the distance from the battery pack to a drive device such as an electric motor, and also ensures a sufficiently large space in the engine compartment (or motor compartment) under the hood of the vehicle. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2013 / 073464 Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, since the lower part of the vehicle is located close to the road surface, external forces such as vibrations are likely to act on the battery pack mounted under the vehicle when the vehicle is running.

[0006] Patent Document 1 introduces a technology for stably mounting a battery pack, which contains a plurality of cells housed in a battery case, on the vehicle frame by hanging and fixing the battery pack to the vehicle frame.

[0007] The battery case 24 in Patent Document 1 is box-shaped and includes a battery cover 38 and a battery tray 38, and multiple battery modules, each including multiple unit cells, are mounted inside the battery case 24. The battery tray 38, which supports the battery modules from below, has a double-bottom structure consisting of an upper plate 43 and a lower plate 44. A middle plate 45 is interposed between the upper plate 43 and the lower plate 44, forming a flow path for cooling air between the upper plate 43 and the lower plate 44.

[0008] In the battery case 24 of Patent Document 1, the battery tray 38 has a double-bottom structure, and the positions of the upper plate 43 and the lower plate 44 are restricted by the middle plate 45. For this reason, it is thought that the battery tray 38 of the battery case 24 buffers to some extent the force acting upward from below on the battery pack due to vibrations and the like while the vehicle is running, and as a result, it is thought that the load acting on the battery pack is reduced to some extent.

[0009] However, for example, if the vehicle runs over a curb, the curb will strike the battery case 24 from below upward, causing an external force to act directly on the battery tray 38 of the battery case 24. In such a case, the battery tray 38 may be damaged, which may have an adverse effect on the battery pack.

[0010] Therefore, there is a need for a technology that can more effectively buffer the force acting on the battery pack from below.

[0011] The present invention has been made in view of the above circumstances, and an object to be achieved is to provide a technique for more effectively cushioning the force acting on a battery pack from below. [Means for solving the problem]

[0012] The battery case structure of the present invention, which solves the above problems, comprises: A battery case structure to be mounted on a vehicle, a battery case that houses at least one battery cell and is disposed above a road surface interference panel that is part of the vehicle body; a bottom support portion disposed in a bottom space formed above the road surface interference panel and below the battery case; The bottom support portion is a pair of rigid case supports disposed below and on both sides of the battery cells, each having a top portion facing the battery case, a bottom portion facing the road surface interference panel, and a wall portion connecting the top portion and the bottom portion; a buffer portion having lower rigidity than the case supports and disposed between the pair of case supports; The top of each of the case supports extends toward the other case support, The buffer portion is interposed between the lower surface of the top portion and the upper surface of the road surface interference panel, The battery case structure is such that the area of ​​the buffer bottom surface facing the road surface interference panel is larger than the area of ​​the buffer top surface facing the top portion. [Effects of the Invention]

[0013] The battery case structure of the present invention can buffer the force acting on the battery pack from below. [Brief explanation of the drawings]

[0014] [Figure 1] 2 is an explanatory diagram illustrating a schematic view of the battery case structure of Example 1 cut along a plane parallel to the up-down direction and the front-rear direction. FIG. [Figure 2] FIG. 2 is an enlarged view of a main part of FIG. [Figure 3] FIG. 2 is an explanatory diagram schematically illustrating a reinforcing member in the battery case structure of Example 1. [Figure 4] FIG. 2 is an explanatory diagram that schematically illustrates a state in which an adhesive material is fixed to a reinforcing member in the battery case structure of Example 1. [Figure 5] 3 is an explanatory view illustrating a state in which the battery case structure of Example 2 is cut at the same position as in FIG. 2. FIG. [Figure 6] 3 is an explanatory view illustrating a state in which the battery case structure of Example 3 is cut at the same position as in FIG. 2. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0015] The battery case structure of the present invention will be specifically described below.

[0016] Unless otherwise specified, the numerical ranges "x to y" described in this specification include the lower limit x and the upper limit y. These upper and lower limit values, as well as the numerical values ​​listed in the embodiments, can be arbitrarily combined to form a numerical range. Furthermore, the upper and lower limit values ​​can be arbitrarily selected from within the numerical range.

[0017] The battery case structure of the present invention is mounted on a vehicle, and the battery case in the battery case structure is disposed above a road surface interference panel that is part of the vehicle body. In other words, the battery case structure of the present invention is mounted on the underside of the vehicle, similar to the battery case structure described in the Background Art section above.

[0018] The road interference panel is part of the vehicle body. It is located on the road side of the vehicle and is the part that will come into contact with the road surface before the battery case does if the vehicle runs over a curb. The road interference panel is connected to other vehicle body components such as the lower cross member, so that force input to the road interference panel from below the vehicle is transmitted and dispersed throughout the entire vehicle body.

[0019] The battery case structure of the present invention comprises a battery case and a bottom support. The battery case houses at least one battery cell and is disposed above the road surface interference panel. A space is formed above the road surface interference panel and below the battery case. This space is referred to as the bottom space. The bottom support part is disposed in the bottom space and supports the battery case from below in the bottom space.

[0020] The bottom support portion in the battery case structure of the present invention includes a pair of case supports and a buffer portion disposed between the pair of case supports.

[0021] The case supports are rigid bodies and are disposed below the cells housed in the battery case and on both sides of the cells. Each case support has a top portion facing the battery case, a bottom portion facing the road surface interference panel, and a wall portion connecting the top and bottom portions. The top portion of each case support extends toward the other case support.

[0022] The case supports can be referred to as members of the bottom support portion that are interposed between the road interference panel and the battery case on both sides of the cell and support the battery case from below. Furthermore, because the case supports are rigid and interposed between the road interference panel and the battery case, they can also be referred to as parts of the battery case structure of the present invention that bear the force input to the road interference panel from below the vehicle before the battery case.

[0023] The buffer section is disposed in the bottom space between the pair of case supports and is interposed between the underside of the top of each case support and the upper surface of the roadway interference panel. Therefore, the buffer section receives the force input to the roadway interference panel from below the vehicle between the case supports disposed on both sides of the cell in the bottom support section, in other words, below the cell. In other words, the buffer section can be said to be a part that plays a role in buffering the force acting on the cell from below the vehicle.

[0024] Here, since the buffer portion has lower rigidity than the case support, when a force is input from below the vehicle to the road surface interference panel, it deforms or breaks before the case support, and by deforming or breaking, the buffer portion can buffer the force acting from below the vehicle on the battery pack.

[0025] The area of ​​the buffer bottom surface facing the road surface interference panel is larger than the area of ​​the buffer top surface facing the top of the case support, so that the buffer can receive the force input to the road surface interference panel from below the vehicle over a wider area and effectively buffer the force acting from below the vehicle.

[0026] By virtue of these cooperation, the battery case structure of the present invention can effectively buffer the force acting on the battery pack from below.

[0027] In the battery case structure of the present invention, the area of ​​the buffer top surface is smaller than the area of ​​the buffer bottom surface, so an area where neither the buffer nor the case support is located remains on the battery pack side of the bottom space. This area is called the void area.

[0028] The void region of the bottom space on the battery pack side can function as a flow path for various cooling fluids, such as air or coolant. By circulating the cooling fluid through the void region, the battery pack can be cooled and maintained at a suitable temperature. In other words, the battery case structure of the present invention can be said to have the function of cooling the battery pack in addition to the function of buffering forces acting on the battery pack from below.

[0029] The battery case structure of the present invention will be described below in detail for each of its constituent elements.

[0030] The battery case structure of the present invention includes a battery case and a bottom support, and optionally further includes a road buffer panel. The road buffer panel is as described above. The material of the road buffer panel is not particularly limited, but metals such as aluminum, iron, and stainless steel are particularly preferred.

[0031] The battery case may be made of any material as long as it can accommodate at least one cell, and various materials such as resin and metal may be selected. It is preferable to provide an internal support section inside the battery case that supports the cell from the radially outer side. The internal support section will be described in detail later.

[0032] The unit cells housed in the battery case of the battery case structure of the present invention generally contain battery components such as a positive electrode, a negative electrode, an electrolyte, terminals, and a separator housed within the battery container. The shape of the unit cells is determined by the shape of the battery container. Typical battery containers include, for example, metal cans having a rectangular or cylindrical shape. Other examples of battery containers include bag-shaped ones made of laminated film. The battery case is preferably used to house a plurality of unit cells electrically connected together as a battery pack.

[0033] The battery case is mounted on the vehicle in a spaced-apart relation above the road surface interference panel, forming a bottom space between the battery case and the road surface interference panel. The bottom support is disposed in this bottom space.

[0034] The bottom support includes a pair of case supports and a buffer.

[0035] The case support is a rigid body, and is the part of the bottom support that supports the battery case from below. Here, "rigid body" means that the rigidity of the case support is higher than that of the buffer section. For example, it is preferable that the case support has a higher bending rigidity than the buffer section. This bending rigidity can be calculated from the Young's modulus and second moment of area of ​​the material used for each component. It is also preferable, for example, to select a material for the case support that is more rigid than the material for the buffer section. As mentioned above, Young's modulus can be used as an indicator of the rigidity of the material.

[0036] The material of the case support may be appropriately selected depending on the desired rigidity. Examples of materials for the case support include metals such as aluminum, iron, and stainless steel; thermoplastic resins such as polypropylene, polycarbonate, and acrylonitrile-styrene-butadiene copolymer (ABS); and thermosetting resins such as phenolic resin and unsaturated polyester. A combination of these materials may also be used. When a resin material is selected as the case support material, reinforcing fibers such as glass fiber and carbon fiber may be blended into the resin material. In this case, the resin material is a so-called fiber-reinforced plastic (FRP), and the reinforcing fibers improve its rigidity and strength.

[0037] The case supports are disposed below the cells in the bottom space, on both sides of the cells. Two case supports disposed on both sides of one cell are referred to as a pair of case supports. The bottom support portion preferably has a number of case supports corresponding to the number of cells. In other words, when a battery case accommodates multiple cells, it is preferable to have multiple pairs of case supports corresponding to the number of cells.

[0038] When the bottom support portion in the battery case structure of the present invention has a plurality of pairs of case supports, some or all of the case supports may be integrated.

[0039] When the case body of the battery case structure of the present invention houses a plurality of unit cells and the bottom support portion has a plurality of pairs of case supports, it is preferable that the unit cells are arranged in a predetermined direction, and it is also preferable that the case supports are arranged along the arrangement direction of the unit cells. Hereinafter, the arrangement direction of the unit cells and the case supports may be referred to as the arrangement direction as necessary.

[0040] The case support has a top portion facing the battery case, a bottom portion facing the road surface interference panel, and a wall portion connecting the top portion and the bottom portion.

[0041] The top portion extends toward the other of the pair of case supports. The top portion is preferably plate-shaped, and may or may not be in direct or indirect contact with the bottom of the battery case.

[0042] The shape of the bottom is not particularly limited, but it is preferable that the bottom is also plate-shaped. The bottom may or may not be in direct or indirect contact with the road surface interference panel.

[0043] The shape of the case support can be appropriately designed depending on the rigidity required for the case support, but since the case support is a component mounted on a vehicle, it is often required to be lightweight. In consideration of reducing the weight of the case support, it is preferable that the case support is hollow. Specifically, suitable shapes for the case support include a hollow columnar shape, a cylindrical shape, a block shape with a U-shaped cross section (a so-called U-shaped groove), and a block shape with an L-shaped cross section.

[0044] The pair of case supports may have the same shape or different shapes. When the bottom support has multiple pairs of case supports, the shapes of the case supports may be the same or different. To reduce the manufacturing cost of the battery case structure of the present invention, it is particularly preferable that all of the case supports have the same shape.

[0045] The case support may simply be sandwiched between the battery case and the road surface interference panel, but for ease of installation in a vehicle, it is preferable that it be fixed to at least one of the battery case and the road surface interference panel. As described above, the case support is the part of the battery case structure of the present invention that bears the force input from under the vehicle to the road surface interference panel before the battery case does, and therefore it is preferable that the case support be fixed to at least the road surface interference panel in order to efficiently bear the force input from under the vehicle to the road surface interference panel.

[0046] There are no particular limitations on the method for fixing the case support to the battery case or road surface interference panel, and various methods such as adhesion, welding, fastening with bolts or clips, etc. may be used. For example, if a vehicle runs over a curb, a large external force acts on the case support from the road surface interference panel side. For this reason, it is preferable that the bottom of the case support and the road surface interference panel are firmly fixed together, and it is particularly preferable that they are fastened together with bolts.

[0047] The wall portion connects the top and bottom portions and extends generally in the vertical direction between the top portion located above and the bottom portion located below. The shape of the wall portion is also not particularly limited, but in order to more efficiently receive the force input to the road surface interference panel from below the vehicle by the case support, it is preferable that the wall portion extend in the vertical direction. Specifically, the intersection angle (minor angle) of the wall portion with the vertical direction is preferably 45° or less, and more preferably 30° or less, 20° or less, 10° or less, or 5° or less. When at least a part of the wall portion is not straight, the above-mentioned intersection angle of the wall portion with respect to the vertical direction means the intersection angle of a plane tangent to the wall portion with respect to the vertical direction.

[0048] The case support may be provided in the bottom space over the entire height direction, i.e., the vertical direction, or may be provided over only a portion of the height direction. When the case support is provided only at a part of the height direction in the bottom space, it is preferable that the bottom of the case support be in direct or indirect contact with the road surface interference panel.

[0049] Furthermore, the case support may be provided only in a portion of the depth direction in the bottom space, i.e., in a direction perpendicular to the up-down direction and the arrangement direction, or may be provided continuously over the entire depth direction. For example, if the cells are arranged in the depth direction in addition to the arrangement direction, one case support may be provided for each cell, or one case support may be provided for multiple cells. In other words, one case support may extend continuously in the depth direction along the side of the multiple cells arranged in the depth direction.

[0050] When the battery case has the above-mentioned internal support portion, it is preferable that the case support and the internal support portion are aligned vertically. In this case, the upward force received by the case support is transmitted to the internal support portion, thereby reducing the force acting on the cells and battery case in the battery pack, and as a result, the force acting on the battery pack from below is more effectively buffered.

[0051] The shape of the support portion within the case is not particularly limited, and examples of suitable shapes for the support portion within the case include shapes similar to those of the support portion described above.

[0052] A buffer section is disposed between the pair of case supports. The buffer section only needs to have lower rigidity than the case supports, and is preferably made of at least one material selected from elastic materials such as rubber and elastomer, and various resin materials. These may be porous materials having pores inside, or non-porous materials having no pores.

[0053] Specific elastic materials that can be selected as the material for the buffer section include various rubbers and elastomers such as urethane rubber, fluororubber, chloroprene rubber, butyl rubber, nitrile rubber, ethylene propylene rubber, etc. Specific resin materials include thermoplastic resins such as polypropylene, polyethylene, polystyrene, polycarbonate, and thermoplastic polyurethane, as well as thermosetting resins such as unsaturated polyester, silicone resin, and thermosetting polyurethane.

[0054] The resin material used for the buffer section may be either hard or soft, but if the bottom support section includes a reinforcing member (described later), it is preferable to select a soft resin, and if the bottom support section does not include the reinforcing member, it is preferable to select a hard resin. Note that if the bottom support section includes a reinforcing member, it is particularly preferable to select an elastic material as the buffer section material. The reinforcing member will be described in detail later.

[0055] For reference, the term "hard resin" used in this specification refers to a resin having a flexural modulus of 2000 kg / cm in a steady state. 2 The above refers to a soft resin whose bending modulus is 700 kg / cm in a steady state. 2 It refers to the following:

[0056] The buffer section is disposed in the bottom space between the pair of case supports and is interposed between the underside of the top of each case support and the upper surface of the road surface interference panel. Therefore, the buffer top surface, which is the upper surface of the buffer section, faces the underside of the top of the case support, and the buffer bottom surface, which is the lower surface of the buffer section, faces the upper surface of the road surface interference panel.

[0057] As described above, the buffer portion is interposed between the lower surface of the top of the case support and the upper surface of the road surface interference panel. Therefore, under normal conditions when no force is being applied to the road surface interference panel from below the vehicle, the lower surface of the top and the buffer top surface may be spaced apart or in contact with each other. Also, the buffer bottom surface and the upper surface of the road surface interference panel may be spaced apart or in contact with each other.

[0058] When a force is input to the road surface interference panel from below the vehicle, in order to effectively buffer the force, the buffer portion needs to abut against the road surface interference panel over a large area.

[0059] On the other hand, under normal circumstances, in order to effectively cool the single cells, the void area of ​​the bottom space, i.e., the area of ​​the bottom space on the battery pack side, needs to function as a flow path for various cooling fluids, such as air and coolant.

[0060] In the buffer portion of the battery case structure of the present invention, the area of ​​the buffer bottom surface is larger than the area of ​​the buffer top surface, and such a buffer portion can contact the road panel over a large area in the portion on the road panel side and can form a large void region in the portion on the battery case side.

[0061] Since the gap area in the bottom space is used as a flow path for the cooling fluid, a larger flow cross-sectional area of ​​the gap area is advantageous in terms of pressure loss. Therefore, it is preferable that the number of gap areas between the pair of case supports is small, and it is particularly preferable that there is only one. Such a gap area is preferably located approximately in the center of the pair of case supports.

[0062] The buffer top surface of the buffer portion faces each of the two top portions of the paired case support, so the buffer portion may have two buffer top surfaces, or may have one buffer top surface formed by connecting the two buffer top surfaces.

[0063] When the buffer section has two buffer top surfaces, the buffer top surface facing the top of the first support, which is one of the pair of case supports, is referred to as the first buffer top surface, and the buffer top surface facing the top of the second support, which is the other of the pair of case supports, is referred to as the second buffer top surface.

[0064] In this case, it is preferable that the buffer portion has a shape that is approximately symmetrical in the direction of arrangement connecting the pair of case supports. The void area is preferably large between the first and second buffer top surfaces and gradually decreases toward the first and second buffer top surfaces. In other words, the void area in the bottom space is preferably gradually decreased from the intermediate position between the first and second buffer top surfaces toward the first and second buffer top surfaces.

[0065] It is preferable that such a buffer section has a shape that is approximately symmetrical in the arrangement direction, in other words, in the direction from the first buffer top surface to the second buffer top surface. The buffer section may be divided into a split section on the first buffer top surface side and a split section on the second buffer top surface side, or may be an integrated section.

[0066] When the buffer section is divided into a first buffer top surface side and a second buffer top surface side, it is preferable that the cross-sectional shape of each of the buffer sections cut along a plane extending in the arrangement direction and the vertical direction be approximately triangular or approximately trapezoidal.

[0067] In addition to the pair of case supports and the buffer parts corresponding to the case supports, the bottom support part preferably further includes a reinforcing member. The reinforcing member is disposed above the buffer part and serves to interfere from above with the upward deformation trajectory of the road surface interference panel in the bottom space, preventing the area between the pair of case supports from being crushed and deformed in the vertical direction. The presence of the buffer part and the bottom support part between the pair of case supports makes it possible to more effectively buffer forces acting from below between the pair of case supports.

[0068] The reinforcing member may be made of an elastic material and have a higher strength than the buffer portion. The term "elastic material" as used herein means a material that can be elastically deformed, and although there are no particular limitations on the material, it is preferable to select at least one material selected from metals such as spring steel, aluminum, and iron, thermoplastic resins such as polypropylene, polyethylene, polystyrene, and thermoplastic polyurethane, unsaturated polyester, silicone resin, and thermosetting resins such as thermosetting polyurethane.

[0069] Here, "higher strength than the buffer section" means that the flexural modulus is greater than that of the buffer section, and the flexural modulus of the reinforcing member is 7000 kg / cm in a steady state. 2 More than 7500kg / cm 2 or more, or 8000 kg / cm 2 The above is particularly preferred.

[0070] The reinforcing member is preferably bridged between the first and second buffer top surfaces of the buffer unit and interposed between the case support and the buffer unit. More specifically, the end of the reinforcing member on the case support side is preferably sandwiched between the top of the case support and the first buffer top surface of the buffer unit or between the top of the case support and the second buffer top surface of the buffer unit. Hereinafter, as necessary, the end of the reinforcing member that is sandwiched between the top of the case support and the first buffer top surface of the buffer section, and the portion that is sandwiched between the top of the case support and the second buffer top surface of the buffer section will be referred to as the clamped end.

[0071] In order to more effectively buffer the force acting from below between the pair of case supports, it is more preferable that the reinforcing member have an arch shape that is recessed toward the road surface interference panel at a position between the first and second buffer top surfaces of the buffer section. Hereinafter, the portion of the reinforcing member that is recessed in an arch shape toward the road surface interference panel may be referred to as the arch bottom, as necessary.

[0072] In order to more effectively buffer the force acting from below between the pair of case supports, it is more preferable that the bottom of the arch of the reinforcing member abuts against the road surface interference panel.

[0073] Such a reinforcing member is preferably shaped to be approximately symmetrical in the arrangement direction, i.e., the direction from the first buffer top surface to the second buffer top surface. The reinforcing member may be divided into a split member on the first buffer top surface side and a split member on the second buffer top surface side, or may be an integrated member.

[0074] The buffer portion and the reinforcing member may be integrated or may remain separate, but it is preferable that the buffer portion and the reinforcing member are integrated in order to maintain the relative positions of the buffer portion and the reinforcing member even when a force is applied from below.

[0075] The method for integrating the buffer portion and the reinforcing member is not particularly limited, and methods such as adhesion, welding, fastening, etc. may be used. In order to easily and inexpensively integrate the buffer section and the reinforcing member, it is preferable to bond the buffer section and the reinforcing member with an adhesive.

[0076] The adhesive may be an adhesive or an adhesive body in which adhesive is applied to both sides of a mount, such as double-sided tape.

[0077] In order to more easily and inexpensively integrate the buffer portion and the reinforcing member, it is preferable that the adhesive material be made up of a plurality of adhesive bodies. When the adhesive is made up of a plurality of adhesive bodies, the plurality of adhesive bodies are arranged between the buffer portion and the reinforcing member. In such a case, it is preferable that the plurality of adhesive bodies are not too long.

[0078] Vibrations and the like caused by the vehicle traveling act on the buffer portion and the reinforcing member in a direction that changes their relative positions, and this in turn causes a force to act on the adhesive body in a peeling direction. If a part of the adhesive peels off from the buffer section or the reinforcing member, the peeled part gradually increases, and it may become impossible to maintain the integration of the buffer section and the reinforcing member by the adhesive. When a long adhesive is used, the adhesive area between the buffer section and the reinforcing member per adhesive is large, and if an individual adhesive peels off, the damage will be excessive, which may make it difficult to maintain the overall integration of the buffer section and the reinforcing member in good condition.

[0079] As described above, the reinforcing member spans the first and second buffer top surfaces of the buffer section and forms an arch shape that is recessed toward the road surface interference panel at a position between the first and second buffer top surfaces. In such a reinforcing member, the length in the arrangement direction connecting the first and second buffer top surfaces is relatively long. Therefore, by making the adhesive bodies extend in a direction intersecting the arrangement direction and arranging them along the arrangement direction, the length of each adhesive body can be made relatively short. This makes it possible to prevent excessive damage caused by the peeling of individual adhesive bodies, as described above.

[0080] As described above, the reinforcing member spans the first and second buffer top surfaces of the buffer section and forms an arch shape that is depressed toward the road surface interference panel at a position between the first and second buffer top surfaces. In such a reinforcing member, the longitudinal direction can be referred to as the curved direction. Therefore, the arrangement direction of the adhesive bodies does not strictly correspond to the direction connecting the first and second buffer top surfaces of the buffer section, but may be a direction that is roughly aligned with the arrangement direction and follows the curved direction of the reinforcing member.

[0081] When a force acts on the battery case structure of the present invention from below, it is preferable that the reinforcing member deform so that the arch bottom faces upward in order to effectively buffer the force. The reinforcing member preferably has a structure for guiding the direction of deformation of the arch bottom.

[0082] Specifically, the reinforcing member preferably recesses downward at least one of a position between the clamping end on the first buffer top surface side and the arch bottom, a position between the clamping end on the second buffer top surface side and the arch bottom, or a position between the arch bottom and the first buffer top surface and a position between the arch bottom and the second buffer top surface. The downwardly recessed portion of the reinforcing portion is referred to as a reinforcing member bending point.

[0083] When a force is applied from below to the battery case structure of the present invention, the reinforcing portion having the reinforcing member bending point bends around the reinforcing member bending point and deforms so that the arch bottom faces upward.

[0084] In this case, it is preferable that the buffer section has a concave shape on the surface facing the bending point of the reinforcing member. The concave portion of the buffer section is called the bending point of the buffer section. When the reinforcing section having the bending point of the reinforcing member bends around the bending point of the reinforcing member and deforms so that the arch bottom is upward, the buffer section having the bending point of the buffer section deforms accordingly.

[0085] The battery case structure of the present invention will be described below with reference to specific examples.

[0086] Example 1 The battery case structure of Example 1 includes an in-vehicle lithium ion secondary battery as a cell, which functions as a battery for driving the vehicle.

[0087] Fig. 1 is an explanatory diagram schematically illustrating the state of the battery case structure of Example 1 cut along a plane parallel to the up-down direction and the front-rear direction. Fig. 2 is an enlarged view of a main part of Fig. 1. Fig. 3 is an explanatory diagram schematically illustrating the reinforcing member in the battery case structure of Example 1, and Fig. 4 is an explanatory diagram schematically illustrating the state in which an adhesive is fixed to the reinforcing member in the battery case structure of Example 1.

[0088] As shown in FIG. 1, the battery case structure 1 of the first embodiment includes a battery case 2 , a bottom support portion 3 , and a road surface interference panel 8 .

[0089] Of these, the road surface interference panel 8 is made of aluminum and has a substantially plate shape. The road surface interference panel 8 is a part of the vehicle body and is a member called an undercover.

[0090] The road surface interference panel 8 is connected to a lower cross member (not shown), which is another part of the vehicle body, by being fastened to the lower cross member (not shown) with bolts (not shown). The road surface interference panel 8 is disposed further below the floor panel (not shown) of the vehicle, and is exposed to the outside on the underside of the vehicle.

[0091] The battery case 2 is made of iron and has a generally box-like shape consisting of an upper case 20 and a lower case 21. The upper case 20 opens downward, and the lower case 21 opens upward. A storage space 29 is defined inside the battery case 2. A plurality of unit cells 90 are housed in the storage space 29 as a battery pack. The plurality of unit cells 90 are arranged in the left-right direction in the drawing, in other words, along the width direction of the vehicle. In the battery case structure 1 of Example 1, the arrangement direction described above is the left-right direction.

[0092] Although not shown, the cells 90 are also arranged in the front-rear direction, that is, in the direction from the front to the back of the paper in FIGS.

[0093] 1 and 2, case internal support portions 28 that support the cells 90 from the radially outer side are provided inside the battery case 2. The case internal support portions 28 are disposed between adjacent cells 90 in the left-right direction, and are arranged in the left-right direction in the same manner as the cells 90.

[0094] The case internal support part 28 is made of the same iron as the battery case 2, and is shaped like an inverted U with the curved part facing upward. The lower end of the case internal support part 28 is welded to the lower case 21.

[0095] 2, the battery case 2 is mounted on the vehicle with the lower case 21 facing downward and spaced apart above the road surface interference panel 8. A bottom support part 3 is disposed in a bottom space BS formed between the battery case 2 and the road surface interference panel 8.

[0096] The bottom support 3 includes four pairs of case supports 4, four buffer parts 5, four reinforcing members 6, and an adhesive material 7 as shown in FIG.

[0097] Each case support 4 is a rigid body made of iron, and is disposed below the corresponding cell 90 and on both sides of the cell 90 in the bottom space BS as shown in FIG. Each case support 4 is generally L-shaped and has a top 4t facing the battery case 2, a bottom 4b facing the road surface interference panel 8, and a wall 4w connecting the top 4t and bottom 4b. Hereinafter, a pair of case supports 4 will be referred to as a case support pair 49 as necessary.

[0098] As shown in Fig. 2, two adjacent case supports 4 are integrally formed to form an inverted, generally U-shaped case support portion 48. The two case supports 4 that make up the same case support portion 48 belong to different adjacent case support pairs 49 (49a, 49b shown in Fig. 2).

[0099] Each case support portion 48 also extends in the depth direction, i.e., the front-to-rear direction. More specifically, the direction in which the case support portion 48 extends is the depth direction of the paper in FIGS. As mentioned above, the cells 90 are also arranged in the front-to-rear direction, and each case support portion 48 can be said to extend continuously in the front-to-rear direction between adjacent cells 90 in the left-to-right direction, on the side of the multiple cells 90 arranged in the front-to-rear direction.

[0100] Of these, the top portion 4t of each case support 4 is in the form of a plate extending in the left-right and front-rear directions, and is in surface contact with the lower surface of the bottom portion 4b of the battery case 2.

[0101] The bottom 4b of each case support 4 also has a plate shape extending in the left-right and front-rear directions. Two case supports 4 belonging to the same case support part 48 are integrated by the bottom 4b. The bottom 4b is in surface contact with the road surface interference panel 8.

[0102] The two case supports 4 belonging to the same case support pair 49 have approximately the same shape and are symmetrical left and right. The two case supports 4 belonging to the same case support part 48 also have approximately the same shape and are symmetrical left and right. Each case support part 48 has approximately the same shape.

[0103] The bottom 4b of the case support 4 is fastened to the road surface interference panel 8 by a bolt B. The tip of the bolt B faces upward. The tip of the bolt B is disposed inside the case support part 48, which is shaped like an inverted letter U, and is located below the battery case 2.

[0104] The wall 4w of the case support 4 is a plate-like member extending in the front-rear direction and generally in the up-down direction, connecting the top 4t and the bottom 4b. In the battery case structure 1 of Example 1, the intersection angle (minor angle) of the wall 4w with the vertical direction is 5° or less, approximately 0°.

[0105] As described above, the top 4t of the case support 4 abuts against the battery case 2, and the bottom 4b abuts against the road surface interference panel 8. Therefore, the case support 4 is provided across the entire bottom space BS in the vertical direction. The case support portion 48 and the case internal support portion 28 are aligned vertically.

[0106] One of the case supports 4 belonging to the same case support pair 49 is referred to as the first support 41, and the other case support 4 belonging to the same case support pair 49 is referred to as the second support 42. The first support 41 is disposed on the left side of the battery cell, and the second support 42 is disposed on the right side of the battery cell.

[0107] A buffer portion 5 is disposed between the first support body 41 and the second support body 42. The buffer portion 5 in the battery case structure 1 of Example 1 is an elastic body made of urethane rubber.

[0108] The buffer section 5 is interposed between the underside of the tops 4t of the first support body 41 and the second support body 42 and the upper surface of the road surface interference panel 8. The buffer top surface 5t, which is the upper surface of the buffer section 5, faces the underside of the tops 4t, and the buffer bottom surface 5b, which is the lower surface of the buffer section 5, faces the upper surface of the road surface interference panel 8. The buffer bottom surface 5b is in surface contact with the upper surface of the road surface interference panel 8.

[0109] The buffer section 5 is divided into two parts, one located on the left side and one located on the right side. Of these, the part located on the left side is referred to as the first buffer section 55, and the part located on the right side is referred to as the second buffer section 56. The first buffer section 55 and the second buffer section 56 are bilaterally symmetrical and have approximately the same shape.

[0110] The area of ​​the buffer bottom surface 5b of each of the first and second buffer segments 55 and 56 is larger than the area of ​​the buffer top surface 5t. A large void region SA is formed in the approximate center of each of the first and second buffer segments 55 and 56. This void region SA is located above the first and second buffer segments 55 and 56, i.e., on the battery case 2 side, in the bottom space BS.

[0111] The first buffer top surface 55t, which is the buffer top surface 5t of the first buffer segment 55, faces the first support top portion 41t, which is the top portion 4t of the first support member 41, and the second buffer top surface 56t, which is the buffer top surface 5t of the second buffer segment 56, faces the second support top portion 42t, which is the top portion 4t of the second support member 42.

[0112] The cross section of the first buffer body 55 taken along a plane extending in the left-right and up-down directions is generally trapezoidal. Similarly, the cross section of the second buffer body 56 taken along a plane extending in the left-right and up-down directions is generally trapezoidal.

[0113] The reinforcing member 6 is disposed above the buffer section 5 and below the case support member 4. The reinforcing member 6 is made of spring steel and has a higher strength than the buffer portion 5. The bending modulus of the reinforcing member 6 is 7000 kg / cm in a steady state. 2 That's about it.

[0114] The reinforcing member 6 spans the first buffer top surface 55t and the second buffer top surface 56t of the buffer unit 5. A clamping end 6e, which is an end of the reinforcing member 6, is interposed between the case support 4 and the buffer unit 5. The reinforcing member 6 forms an arch shape that is recessed toward the road surface interference panel 8 at a position between the first buffer top surface 55t and the second buffer top surface 56t of the buffer unit 5. The arch bottom 6t of the reinforcing member 6 is in surface contact with the road surface interference panel 8.

[0115] The reinforcing member 6 in the battery case structure 1 of Example 1 is divided into two parts, one located on the left side and one located on the right side. Of these, the part located on the left side is referred to as the first reinforcing part 61, and the part located on the right side is referred to as the second reinforcing part 62. The first reinforcing part 61 and the second reinforcing part 62 are bilaterally symmetrical and have approximately the same shape.

[0116] The end of the first reinforcing piece 61 on the first support body 41 side is sandwiched between the first support top portion 41t and the first buffer top surface 55t. The end of the second reinforcing piece 62 on the second support body 42 side is sandwiched between the second support top portion 42t and the second buffer top surface 56t.

[0117] The buffer section 5 and the reinforcing member 6 are bonded and integrated with an adhesive 7. The adhesive 7 includes a plurality of adhesive bodies 71, and as shown in FIG. 4, the adhesive bodies 71 are double-sided tape.

[0118] Each adhesive body 71 has a generally elongated rectangular shape. Each adhesive body 71 is first attached to the reinforcing member 6, and then attached to the buffer section 5 together with the reinforcing member 6.

[0119] 3, the first reinforcing segment 61 of the reinforcing member 6 has a generally rectangular curved plate shape with the longitudinal direction oriented in the left-right direction. Although not shown, the first reinforcing segment 61 of the reinforcing member 6 also has generally the same shape.

[0120] As shown in FIG. 4, the adhesive bodies 71 extend in the front-rear direction perpendicular to the left-right direction, and are arranged along the left-right direction.

[0121] When a force is input from below to a vehicle equipped with the battery case structure 1 of Example 1, the force is first received by the road surface interference panel 8. A portion of the force input to the road surface interference panel 8 is then transmitted and dispersed throughout the entire vehicle body. The case support body 4, which is in contact with the road surface interference panel 8 above the road surface interference panel 8, receives another portion of the force input to the road surface interference panel 8 from below the vehicle, on the side of the cell 90.

[0122] In the battery case structure 1 of Example 1, a reinforcing member 6 is disposed between a pair of case supports 4. The reinforcing member 6 is rigid and located above the road surface interference panel 8, and therefore supports the road surface interference panel 8 from above, below the cells 90, as the panel 8 deforms upward due to an external force from below. The reinforcing member 6 is also elastic, and is elastically deformed when pressed upward by the road surface interference panel 8, which deforms upward, thereby cushioning the force acting upward via the road surface interference panel 8.

[0123] The buffer section 5, which is disposed below the reinforcing section and above the road surface interference panel 8, receives the force input to the road surface interference panel 8 from below the vehicle, below the unit cells 90. At this time, the buffer section 5 elastically deforms to buffer the force.

[0124] By virtue of these cooperation, the battery case structure 1 of the first embodiment can effectively buffer the force acting on the battery pack from below.

[0125] Example 2 The battery case structure 1 of Example 2 is generally the same as the battery case structure 1 of Example 1 except for the shapes of the reinforcing member 6 and the buffer portion 5. FIG. 5 is an explanatory view illustrating a state in which the battery case structure 1 of Example 2 is cut at the same position as in FIG. The battery case structure 1 of the second embodiment will be described below, focusing on the differences from the battery case structure 1 of the first embodiment.

[0126] The reinforcing member 6 in the battery case structure 1 of Example 2 has two reinforcing member bending points 6b, specifically a first reinforcing member bending point 61b and a second reinforcing member bending point 62b.

[0127] Specifically, the reinforcing member 6 in the battery case structure 1 of Example 2 is made up of a first reinforcing piece 61 and a second reinforcing piece 62, similar to the reinforcing member 6 in the battery case structure 1 of Example 1. The first reinforcing segment 61 is curved so as to be depressed downward at a position between the arch bottom 6t and the clamping end 6e. This depressed portion is the first reinforcing member bending point 61b. The second reinforcing segment 62 is curved so as to be depressed downward at a position between the arch bottom 6t and the clamping end 6e. This depressed portion is the second reinforcing member bending point 62b.

[0128] The buffer section 5 in the battery case structure 1 of Example 2 has two buffer section bending points 5b, specifically a first buffer section bending point 51b and a second buffer section bending point 52b.

[0129] The buffer section 5 in the battery case structure 1 of the second embodiment is made up of a first buffering section 55 and a second buffering section 56, similar to the buffer section 5 in the battery case structure 1 of the first embodiment. In the first buffer segment 55, the surface facing the first reinforcing member bending point 61b is concave along the first reinforcing member bending point 61b. This concave portion is the first buffer section bending point 51b. Similarly, in the second buffer segment 56, the surface facing the second reinforcing member bending point 62b is concave along the second reinforcing member bending point 62b. This concave portion is the second buffer section bending point 52b.

[0130] When a force acts from below on the battery case structure 1 of Example 2, the force also acts from below on the arch bottom 6t of the reinforcing member 6. At this time, the reinforcing member 6 bends around the first buffer bending point 51b and the second buffer bending point 52b, and the arch bottom 6t deforms upward. The first buffer bending point 51b and the second buffer bending point 52b can be said to be structures that guide the deformation direction of the arch bottom 6t of the reinforcing member 6.

[0131] At this time, the buffer section 5 follows the reinforcing member 6 and is bent and deformed around the first buffer section bending point 51b and the second buffer section bending point 52b.

[0132] The reinforcing member 6 in the battery case structure 1 of Example 2 bends around the first buffer bending point 51b and the second buffer bending point 52b, thereby deforming so that the arch bottom 6t faces upward. Therefore, when the reinforcing member 6 deforms, interference of the arch bottom 6t with the road surface interference panel 8, the case support 48, etc. can be suppressed, and forces acting on the battery case structure 1 from below can be effectively buffered. As a result, the battery case structure 1 of the second embodiment can more effectively buffer the force acting on the battery pack from below.

[0133] Example 3 The battery case structure 1 of Example 3 is substantially the same as the battery case structure 1 of Example 1, except that it does not have a reinforcing member 6 and the buffer portion 5 is made of a hard resin. FIG. 6 is an explanatory view illustrating a state in which the battery case structure 1 of Example 3 is cut at the same position as in FIG. The battery case structure 1 of the third embodiment will be described below, focusing on the differences from the battery case structure 1 of the first embodiment.

[0134] The battery case structure 1 of Example 3 does not have a reinforcing member 6, and the first buffer top surface 55t of the first buffer portion 55 is in direct contact with the top portion 4t of the first support 41, and the second buffer top surface 56t of the second buffer portion 56 is in direct contact with the top portion 4t of the second support 42. The first buffer body 55 and the second buffer body 56 are made of polycarbonate, which is a hard resin.

[0135] The battery case structure 1 of Example 3 does not have a reinforcing member 6, and instead a hard resin is selected as the material for the buffer portion 5. Therefore, the buffer portion 5 in the battery case structure 1 of Example 3 has both the functions of the reinforcing member 6 and the buffer portion 5 in the battery case structure 1 of Example 1. Therefore, the battery case structure 1 of Example 3 can also effectively buffer the force acting from below between the pair of case supports 4.

[0136] Although the present invention has been described above, the present invention is not limited to the above-described embodiments, etc., and it is possible to implement the present invention by appropriately extracting and combining elements described in the embodiments, etc., and to make various modifications within the scope that does not deviate from the spirit of the present invention. Furthermore, the specification of the present invention discloses not only the citation relationships of the claims at the time of filing but also the technical idea of ​​appropriately combining the matters described in the claims. [Explanation of symbols]

[0137] 1: Battery case structure 2: Battery case 3: Bottom support 4: Case support 4t: Top 4b: Bottom 4w: Wall 41: First support 42: Second support 5: Buffer section 5b: Buffer bottom surface 5t: Buffer top surface 55t: First buffer top surface 56t: 2nd buffer top surface 5b, 51b, 52b: Buffer bending point 6: Reinforcing member 6e, 61e, 62e: Clamping end 6t: bottom of arch 6b, 61b, 62b: bending points of reinforcing members 7: Adhesive material 71: Adhesive body 8: Road surface interference panel 90: Single battery BS: Bottom space SA: Void area

Claims

1. A battery case structure to be mounted on a vehicle, a battery case that houses at least one battery cell and is disposed above a road surface interference panel that is part of the vehicle body; a bottom support portion disposed in a bottom space formed above the road surface interference panel and below the battery case; The bottom support portion is a pair of rigid case supports disposed below and on both sides of the battery cells, each having a top portion facing the battery case, a bottom portion facing the road surface interference panel, and a wall portion connecting the top portion and the bottom portion; a buffer portion having lower rigidity than the case supports and disposed between the pair of case supports; The top of each of the case supports extends toward the other case support, The buffer portion is interposed between the lower surface of the top portion and the upper surface of the road surface interference panel, The area of ​​the buffer bottom surface of the buffer portion facing the road surface interference panel is larger than the area of ​​the buffer top surface facing the top portion.

2. the buffer section has a first buffer top surface facing the top of a first support, which is one of the pair of case supports, and a second buffer top surface facing the top of a second support, which is the other of the pair of case supports; 2. The battery case structure according to claim 1, wherein a void region of the bottom space where the bottom support portion is not disposed is large at a position between the first buffer top surface and the second buffer top surface, and gradually becomes smaller toward the first buffer top surface side and the second buffer top surface side.

3. 3. The battery case structure according to claim 1, wherein the buffer portion is made of an elastic material or a hard resin.

4. the bottom support portion has a reinforcing member disposed above the buffer portion; 3. The battery case structure according to claim 2, wherein the reinforcing member is made of an elastic material and has a strength higher than that of the buffer portion, and is bridged between the first buffer top surface and the second buffer top surface, interposed between the case support body and the buffer portion, and has an arch shape that is recessed toward the road surface interference panel at a position between the first buffer top surface and the second buffer top surface.

5. 5. The battery case structure of claim 4, wherein the reinforcing member has a bending point that is recessed downward at at least one of a position between a clamping end portion between the case support and the first buffer top surface and an arch bottom portion that recesses in an arch shape toward the road surface interference panel, and a position between a clamping end portion between the case support and the second buffer top surface and the arch bottom portion.

6. The battery case structure according to claim 5 , wherein the buffer portion has a concave buffer portion bending point on a surface facing the reinforcing member bending point.

7. The battery case structure according to claim 4 , wherein the buffer portion and the reinforcing member are bonded together with an adhesive.

8. the adhesive material includes a plurality of adhesive bodies; The battery case structure according to claim 7 , wherein the adhesive members extend in a direction intersecting an arrangement direction connecting the first buffer top surface and the second buffer top surface of the reinforcing member, and are arranged along the arrangement direction.

9. The battery case structure according to claim 1 or 2, further comprising a road surface interference panel.

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