Battery case for electric vehicle and manufacturing method thereof

Abstract

To provide a battery case for an electric vehicle capable of improving the sealability and being configured simply while suppressing reduction in assembly accuracy due to welding thermal strain of a frame, and to provide a method of manufacturing the same.SOLUTION: A battery case for an electric vehicle comprises: a frame 110 configured in a rectangular frame shape when seen from a vertical direction of a vehicle, demarcating a space TH therein; a cross member 150 arranged inside the frame so as to divide the space TH; and a bathtub-like tray 120 that houses a battery and is arranged at least partially in the space of the frame. The frame includes: a pair of first skeleton members 111A and 111B extending in a front-rear direction of the vehicle; and a pair of second skeleton members 112A and 112B extending in a vehicle width direction. The cross member includes a first auxiliary member 151 and a second auxiliary member 152. The pair of first skeleton members and the pair of second skeleton members are joined mechanically. The first auxiliary member and the second auxiliary member are joined mechanically.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a battery case for an electric vehicle and a method for manufacturing the same. [Background technology]

[0002] Electric vehicles and other electrically powered vehicles need to be equipped with large-capacity batteries to ensure sufficient driving range, while at the same time requiring a spacious cabin. To meet both of these requirements, many electric vehicles house large-capacity batteries in a battery case that is mounted on the entire underfloor area of ​​the vehicle. Therefore, battery cases for electric vehicles require high sealing properties to prevent water from entering from the road surface and to prevent malfunctions of electronic components, as well as high crash strength to protect the battery inside.

[0003] For example, Patent Document 1 discloses a battery case in which the sealing performance is improved by using a tray formed into a bathtub shape by cold pressing a metal plate. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2017-226353 A Summary of the Invention [Problem to be solved by the invention]

[0005] In the battery case of Patent Document 1, the bathtub-shaped tray improves sealing performance, but in order to form a frame to house the tray, it is necessary to join the vertical bones, the front beam, and the rear beam by a joining means such as welding. In particular, using welding as a joining means not only complicates the manufacturing process, but also poses the risk of a decrease in the assembly accuracy of the frame due to welding heat distortion.

[0006] An object of the present invention is to provide a battery case for an electric vehicle and a manufacturing method thereof that improves sealing performance by using a bathtub-shaped tray, while simplifying the construction while suppressing a decrease in assembly accuracy due to welding heat distortion of the frame and cross member that houses the tray. [Means for solving the problem]

[0007] A first aspect of the present invention provides a battery case for an electric vehicle comprising a frame configured in a rectangular frame shape when viewed from the top-bottom direction of the vehicle and defining a space on the inside, a cross member arranged inside the frame so as to divide the space, and a bathtub-shaped tray that houses a battery and is arranged at least partially within the space of the frame, wherein the frame includes a pair of first skeletal members made of aluminum extrusions and extending in the fore-and-aft direction of the vehicle, and a pair of second skeletal members made of aluminum extrusions and extending in the vehicle width direction, the cross member includes a first auxiliary member made of aluminum extrusions and connecting the pair of first skeletal members, and a second auxiliary member made of aluminum extrusions and connecting the pair of second skeletal members, the pair of first skeletal members and the pair of second skeletal members are mechanically joined, and the first auxiliary member and the second auxiliary member are mechanically joined.

[0008] According to this configuration, the pair of first skeletal members and the pair of second skeletal members are joined by a mechanical joining method, and the first auxiliary member and the second auxiliary member are joined by a mechanical joining method, so that complicated welding is not required. Here, the mechanical joining method is a joining method using mechanical energy, unlike a metallurgical joining method such as welding. The mechanical joining method includes, for example, joining using fitting, and joining methods using bolts, nuts, and rivets. Therefore, it is possible to suppress a decrease in the assembly accuracy of the frame due to welding heat distortion, and to easily configure the frame and the cross member. In addition, since the tray is formed in a bathtub shape, there are no seams in the tray, and high sealing properties that can prevent water from entering from the road surface, etc. can be ensured. In addition, since the cross member supports the frame from the inside, high rigidity can be ensured.

[0009] The pair of first skeletal members may have a first engagement portion, the pair of second skeletal members may have a second engagement portion, at least one of the first engagement portion and the second engagement portion may have a concave shape, and the first engagement portion and the second engagement portion may be engaged with each other, thereby directly joining the pair of first skeletal members and the pair of second skeletal members.

[0010] According to this configuration, the pair of first skeletal members and the pair of second skeletal members are directly joined together by the engagement of the first engaging portion and the second engaging portion. Therefore, the frame can be easily constructed. Here, the above-mentioned engagement refers to a fitting with structural positional constraints, without requiring a separate joining means such as welding. Such a fitting with structural positional constraints allows accurate positioning, thereby improving dimensional accuracy and joining accuracy.

[0011] The second engagement portion may have a recess that is recessed upward in the vehicle vertical direction, and an insertion portion that forms part of the recess and is convex downward in the vehicle vertical direction, and the first engagement portion may have a recess that is recessed downward in the vehicle vertical direction, and an insertion hole that is aligned with the insertion portion and into which the insertion portion is inserted.

[0012] According to this configuration, the engagement structure of the first engagement portion and the second engagement portion can be specifically realized. In particular, the horizontal positions of the pair of first skeletal members and the pair of second skeletal members are restrained by fitting the recesses recessed in the vehicle vertical direction into each other. Also, since the insertion portion is inserted into the insertion hole, the engagement can be prevented from being released. Furthermore, since the bathtub-shaped tray is placed on the frame from above, the first engagement portion and the second engagement portion can be covered by the tray. Therefore, the position in the vehicle vertical direction is also restrained, and the engagement can be prevented from being released.

[0013] The recess of the first engagement portion may have a first inclined portion that is inclined so as to narrow at a first angle downward in the vehicle vertical direction when viewed from the vehicle width direction, and the second engagement portion may have a second inclined portion that is aligned with the first inclined portion and is inclined so as to narrow at the first angle downward in the vehicle vertical direction when viewed from the vehicle width direction.

[0014] According to this configuration, the gap between the first engagement portion and the second engagement portion becomes smaller as they engage with each other, which makes assembly easier and further reduces or prevents rattling after assembly.

[0015] The pair of first framework members may have first holes provided facing the space, and both ends of the first auxiliary member may be inserted into the first holes.

[0016] According to this configuration, the connection between the pair of first framework members by the first auxiliary member can be specifically designed. In particular, the configuration in which the first auxiliary member is inserted into the first hole portion is simple and low cost.

[0017] The first hole portion may have a third inclined portion that is inclined so as to narrow at a second angle downward in the vehicle vertical direction when viewed from the vehicle width direction, and the first auxiliary member may have a fourth inclined portion that is aligned with the third inclined portion and is inclined so as to narrow at the second angle downward in the vehicle vertical direction when viewed from the vehicle width direction.

[0018] According to this configuration, the gap between the first hole portion and the first auxiliary member becomes smaller as they engage with each other, which makes assembly easier and can further reduce or prevent rattling after assembly.

[0019] The pair of second skeletal members may have second holes provided facing the space, and both ends of the second auxiliary member may be inserted into the second holes.

[0020] According to this configuration, the connection between the pair of second skeletal members by the second auxiliary member can be specifically designed. In particular, the configuration in which the second auxiliary member is inserted into the second hole portion is simple and low cost.

[0021] The second hole portion may have a fifth inclined portion that is inclined so as to narrow at a third angle toward the upward direction in the vehicle vertical direction when viewed from the vehicle fore-and-aft direction, and the second auxiliary member may have a sixth inclined portion that is aligned with the fifth inclined portion and is inclined so as to narrow at the third angle toward the upward direction in the vehicle vertical direction when viewed from the vehicle fore-and-aft direction.

[0022] According to this configuration, the gap between the second hole portion and the second auxiliary member becomes smaller as they engage with each other, which makes assembly easier and can further reduce or prevent rattling after assembly.

[0023] The first auxiliary member may have a third engagement portion, the second auxiliary member may have a fourth engagement portion, at least one of the third engagement portion and the fourth engagement portion may have a concave shape, and the first auxiliary member and the second auxiliary member may be joined by the engagement of the third engagement portion and the fourth engagement portion.

[0024] According to this configuration, by joining the first auxiliary member and the second auxiliary member, the rigidity of the entire frame can be improved.

[0025] The third engagement portion may have a recessed portion that is recessed downward in the vehicle vertical direction, and the fourth engagement portion may have a recessed portion that is recessed upward in the vehicle vertical direction.

[0026] According to this configuration, the engagement structure of the third engagement portion and the fourth engagement portion can be specifically realized. In particular, the horizontal positions of the first auxiliary member and the second auxiliary member are restricted by fitting the recesses recessed in the vertical direction of the vehicle into each other. In addition, since the bathtub-shaped tray is placed on the frame from above, the third engagement portion and the fourth engagement portion can be covered by the tray. Therefore, the position in the vertical direction of the vehicle is restricted and the disengagement can be prevented.

[0027] The third engagement portion may have a seventh inclined portion that is inclined so as to narrow at a fourth angle downward in the vehicle vertical direction when viewed from the vehicle fore-and-aft direction, and the second auxiliary member may have an eighth inclined portion that is aligned with the seventh inclined portion and is inclined so as to narrow at the fourth angle downward in the vehicle vertical direction when viewed from the vehicle fore-and-aft direction.

[0028] According to this configuration, the gap between the third engagement portion and the fourth engagement portion becomes smaller as they engage with each other, which makes assembly easier and can further reduce or prevent rattling after assembly.

[0029] The fourth engagement portion may have a ninth inclined portion that is inclined so as to narrow at a fifth angle toward the upward direction in the vehicle vertical direction when viewed from the vehicle width direction, and the first auxiliary member may have a tenth inclined portion that is aligned with the ninth inclined portion and is inclined so as to narrow at the fifth angle toward the upward direction in the vehicle vertical direction when viewed from the vehicle width direction.

[0030] According to this configuration, the gap between the third engagement portion and the fourth engagement portion becomes smaller as they engage with each other, which makes assembly easier and can further reduce or prevent rattling after assembly.

[0031] The pair of first skeletal members may be located at the highest in the vehicle vertical direction and have a first top surface extending horizontally, and the pair of second skeletal members may be located at the highest in the vehicle vertical direction and have a second top surface extending horizontally, and the first top surface and the second top surface may be flush with each other.

[0032] According to this configuration, the occurrence of a gap between the frame and the tray can be suppressed or prevented, and therefore the sealing performance can be improved.

[0033] The pair of first skeletal members may be tubular with the interior divided in the vertical direction of the vehicle by a first partition wall extending horizontally, and the pair of second skeletal members may be tubular with the interior divided in the vertical direction of the vehicle by a second partition wall extending horizontally, and the first partition wall and the second partition wall may be arranged at the same height in the vertical direction of the vehicle.

[0034] According to this configuration, when a horizontal collision load is applied to the frame, the collision load can be transmitted to the entire frame via the first partition wall and the second partition wall, so that the entire frame can absorb the collision load, thereby improving collision resistance.

[0035] The device may further include joining members for joining the pair of first skeletal members and the pair of second skeletal members, and by joining the pair of first skeletal members and the joining members by a mechanical joining method, and by joining the pair of second skeletal members and the joining members by a mechanical joining method, the pair of first skeletal members and the pair of second skeletal members may be indirectly joined via the joining members.

[0036] According to this configuration, the pair of first skeletal members and the pair of second skeletal members can be joined without performing complex processing on the pair of first skeletal members and the pair of second skeletal members which are extruded materials.

[0037] The tray may be pressed against the frame.

[0038] According to this configuration, the frame and the tray can be easily integrated without the need for welding.

[0039] A negative angle portion may be provided in which a negative angle is formed at least partially inward in the horizontal direction from a bottom wall of the tray toward the upper side in the vehicle vertical direction.

[0040] According to this configuration, even if an upward force is applied to the tray, the negative corner portion is caught by the frame, so that the tray can be prevented from coming off the frame. In other words, the pressure contact between the tray and the frame can be prevented from being released.

[0041] A second aspect of the present invention includes preparing a flat-plate-shaped formed member, a pair of first skeletal members which are aluminum extrusions, a pair of second skeletal members which are aluminum extrusions, a first auxiliary member which is an aluminum extrusion, and a second auxiliary member which is an aluminum extrusion, arranging the pair of first skeletal members so as to extend in the front-rear direction of the vehicle, arranging the pair of second skeletal members so as to extend in the vehicle width direction, and mechanically joining the pair of first skeletal members and the pair of second skeletal members to form a frame which is rectangular when viewed from the top-bottom direction of the vehicle and defines a space inside, and connecting the pair of first skeletal members so as to divide the space. the first auxiliary member connecting the pair of second skeletal members to form a cross member, overlapping the molded member on the frame and the cross member, applying pressure to the molded member from the opposite side to the frame and the cross member, and pressing the molded member against the frame and the cross member to cause it to bulge within the space, thereby deforming the molded member into a bathtub-shaped tray and pressing it against the frame and the cross member.

[0042] According to this method, the pair of first skeletal members and the pair of second skeletal members are joined by a mechanical joining method, and the first auxiliary member and the second auxiliary member are joined by a mechanical joining method, so that complicated welding is not required. Here, the mechanical joining method is a joining method using mechanical energy, unlike a metallurgical joining method such as welding. The mechanical joining method includes, for example, joining methods using bolts and nuts, rivets, etc. Therefore, it is possible to suppress a decrease in the assembly accuracy of the frame due to welding heat distortion, and the frame and cross member can be easily configured. In addition, since the tray is formed in a bathtub shape, there are no seams in the tray, and high sealing properties that can prevent water from entering from the road surface, etc. can be ensured. In addition, since the cross member supports the frame from the inside, high rigidity can be ensured.

[0043] The manufacturing method of the battery case for an electric vehicle may further include preparing an elastic body into which liquid is injected, positioning the elastic body so as to be in contact with the molded member, and injecting pressurized liquid into the elastic body to apply pressure to the molded member from the opposite side to the frame and the cross member, pressing the molded member against the frame and the cross member and causing it to bulge in the space, thereby deforming the molded member into a bathtub-shaped tray and pressing it against the frame.

[0044] This method makes it easy to bulge and deform the workpiece into a complex shape such as one in which a cross member is arranged. In other words, the amount of bulging of the workpiece can be increased, and the tray can be firmly pressed against the frame and the cross member.

[0045] The manufacturing method of the battery case for an electric vehicle may further include performing pre-forming using a mold before the deformation and pressure welding.

[0046] According to this configuration, the step of deforming the tray to fit the shapes of the frame and the cross member is performed at least twice, which makes it difficult for distortion to occur and improves formability compared to a case in which the formed member is deformed in one step. Effect of the Invention

[0047] According to the present invention, in a battery case for an electric vehicle and a manufacturing method thereof, the bathtub-shaped tray improves sealing performance, and the frame that houses the tray can be easily constructed while suppressing a decrease in assembly accuracy due to welding heat distortion. [Brief description of the drawings]

[0048] [Figure 1] 1 is a side view of an electric vehicle equipped with an electric vehicle battery case according to a first embodiment of the present invention. [Diagram 2] FIG. [Diagram 3] FIG. [Figure 4] FIG. [Diagram 5] FIG. [Figure 6] FIG. 4 is an exploded perspective view of a first skeletal member and a first auxiliary member. [Figure 7] 7 is a cross-sectional view taken along line VII-VII in FIG. 4 . [Figure 8] FIG. 4 is an exploded perspective view of a second skeletal member and a second auxiliary member. [Figure 9] IX-IX cross-sectional view of FIG. 4. [Figure 10] 5 is a cross-sectional view taken along line XX in FIG. 4 . [Figure 11] 1 is a cross-sectional view taken along line XI-XI in FIG. 4 . [Figure 12] FIG. 2 is a perspective view of a molded member, a first skeletal member, and a second skeletal member; [Figure 13] 4A to 4C are first cross-sectional views showing a manufacturing method of the battery case. [Figure 14] 5 is a second cross-sectional view showing the manufacturing method of the battery case. [Figure 15] 4 is a third cross-sectional view showing the manufacturing method of the battery case. [Figure 16] FIG. [Figure 17]FIG. 11 is an exploded perspective view of a portion of a battery case in a second embodiment of the present invention. [Figure 18] FIG. 11 is an exploded perspective view of a portion of a battery case in a modified example of the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0049] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

[0050] (First embodiment) With reference to FIG. 1, the electric vehicle 1 is a vehicle that runs by driving a motor (not shown) with power supplied from a battery 30. For example, the electric vehicle 1 may be an electric vehicle or a plug-in hybrid vehicle. The type of the vehicle is not particularly limited, and may be a passenger car, a truck, a work vehicle, or other mobility. In the following, a passenger car type electric vehicle will be described as an example of the electric vehicle 1.

[0051] The electric vehicle 1 is equipped with a motor and high-voltage equipment (not shown) in a vehicle body front portion 10. The electric vehicle 1 is also equipped with an electric vehicle battery case 100 (hereinafter also simply referred to as the battery case 100) that stores a battery 30, substantially covering the entire surface under the floor of the vehicle compartment R in the vehicle body center portion 20. In Fig. 1, the front-rear direction of the electric vehicle 1 is indicated as the X direction, and the up-down direction is indicated as the Z direction. The same notation is used in the subsequent figures, and the vehicle width direction is indicated as the Y direction in Fig. 2 and subsequent figures.

[0052] 2, the battery case 100 is disposed inside the rocker member 200 in the vehicle width direction. The rocker member 200 extends in the vehicle front-rear direction at the lower ends of the electric vehicle 1 (see FIG. 1) in the vehicle width direction. The rocker member 200 is formed by bonding together a number of metal plates, and has the function of protecting the vehicle interior R and the battery case 100 against impacts from the sides of the electric vehicle 1.

[0053] 2 to 4, the battery case 100 includes a frame 110 that defines a through hole TH, a bathtub-shaped tray 120, and a top cover 130 (see FIG. 2) and an under cover 140 (see FIG. 2) that are arranged to sandwich the above and below. Here, the through hole TH is an example of a space according to the present invention.

[0054] 5, the frame 110 is a member forming the framework of the battery case 100. The frame 110 is configured in a rectangular frame shape when viewed from the vehicle top-bottom direction by joining a pair of first framework members 111A, 111B and a pair of second framework members 112A, 112B, and defines a through hole TH on the inside. Hereinafter, the inside of the frame 110 refers to the center side of the rectangular frame shape, and the outside refers to the opposite side. In addition, hereinafter, the first framework member 111A and the second framework member 112A will be mainly described, but the first framework member 111B and the second framework member 112B have the same configuration.

[0055] Referring to FIG. 5, the first frame member 111A is an aluminum extrusion extending linearly in the vehicle longitudinal direction. The first frame member 111A has a first frame member main body 111a and a first frame member reinforcing portion 111b disposed on the outside of the first frame member main body 111a. The first frame member main body 111a is hollow (tubular), located at the topmost position in the vehicle vertical direction, and has a top surface (first top surface) 111l extending horizontally. The inside of the first frame member main body 111a is partitioned in the vehicle vertical direction by a partition wall (first partition wall) 111c extending horizontally (in the vehicle width direction and the vehicle longitudinal direction). The first frame member reinforcing portion 111b is hollow. Similarly, the inside of the first frame member reinforcing portion 111b is partitioned in the vehicle vertical direction by a partition wall 111d extending horizontally.

[0056] The first frame member 111A has a first engagement portion 111e at both ends in the vehicle front-rear direction. The first engagement portion 111e has a concave shape. In detail, the first engagement portion 111e has a recess 111f that is recessed downward in the vehicle up-down direction, and an insertion hole 111m that is provided in the first frame member reinforcing portion 111b so as to be aligned with an insertion portion 112k described later and into which the insertion portion 112k is inserted. The recess 111f is composed of a bottom surface 111f1 and two side surfaces 111f2 and 111f3. The bottom surface 111f1 is composed of a partition wall 111c. One side surface 111f2 is provided perpendicular to the bottom surface 111f1 (i.e., along the vertical direction), and the other side surface (first inclined portion) 111f3 is provided at an inclination in accordance with the inclination of an inclined surface 112d1 of the second frame member 112A described later.

[0057] The second skeletal member 112A is an aluminum extrusion extending linearly in the vehicle width direction. The second skeletal member 112A is hollow (tubular), located at the top of the vehicle vertical direction, and has a top surface (second top surface) 112j extending horizontally. The interior of the second skeletal member 112A is partitioned in the vehicle vertical direction by a partition wall (second partition wall) 112a. The second skeletal member 112A has an inner surface 112d on the inside in the vehicle longitudinal direction. The inner surface 112d includes an inclined surface (second inclined portion) 112d1 above the partition wall 112a and a vertical surface 112d2 below the partition wall 112a. As described above, the inclined surface 112d1 is inclined from the vertical direction to match the other side surface 111f3, while the vertical surface 112d2 extends along the vertical direction (vehicle vertical direction).

[0058] The second frame member 112A has second engagement parts 112b at both ends. The second engagement parts 112b have a concave shape. In detail, the second engagement parts 112b have a recess 112c that is concave upward in the vehicle vertical direction, and an insertion part 112k that constitutes a part of the recess 112c and is convex downward in the vehicle vertical direction. The recess 112c is composed of a top surface 112c1 and two side surfaces 112c2 and 112c3. The top surface 112c1 of the recess 112c is composed of the partition wall 112a. The two side surfaces 112c2 and 112c3 of the recess 112c are provided perpendicular to the top surface 112c1 (i.e., along the vertical direction).

[0059] The first engaging portion 111e and the second engaging portion 112b have shapes that engage with each other. Here, the engagement is one of the mechanical joining methods, and refers to fitting with structural positional constraints without requiring a separate joining means such as welding. Here, the mechanical joining method is a joining method using mechanical energy, unlike a metallurgical joining method such as welding. Although different from this embodiment, the mechanical joining method may include, for example, a joining method using bolts and nuts, rivets, etc. In this embodiment, the first skeletal member 111A and the second skeletal member 112A are directly joined by engaging the recess 111f of the first engaging portion 111e and the recess 112c of the second engaging portion 112b. Note that the first engaging portion 111e and the second engaging portion 112b may be welded to the extent that no welding heat distortion occurs. For example, they may be welded at the welded portions W1, W2, and W3 shown in FIG. 4. The welded portions W1 and W2 are the portions where the top surface 111l and the top surface 112j contact each other. The welded portion W3 is a portion where the insertion portion 112k and the bottom wall 111b1 of the first frame member reinforcing portion 111b come into contact.

[0060] 4, when the first engagement portion 111e and the second engagement portion 112b are engaged with each other, the top surface 111l and the top surface 112j are flush with each other. The partition wall 111c and the partition wall 112a are disposed at the same height in the vertical direction of the vehicle.

[0061] In this embodiment, the frame 110 that defines the through hole TH is described as an example, but the shape of the frame 110 is not limited to a through shape. For example, the frame 110 may have a concave shape instead of a through shape, that is, may have a bottom wall.

[0062] In addition, in the present embodiment, a structure in which both the first engagement portion 111e and the second engagement portion 112b have a shape recessed in the vehicle vertical direction is exemplified, but the first engagement portion 111e and the second engagement portion 112b are not limited to this shape and may be any shape capable of joining the first frame member 111A and the second frame member 112A. For example, a structure in which only one of the first engagement portion 111e and the second engagement portion 112b has a recessed shape may be used. The recessed shape is not limited to a shape recessed in the vehicle vertical direction, and may be a shape recessed in other directions. Also, an engagement structure other than a recessed shape may be used.

[0063] 4, in this embodiment, a cross member 150 is disposed inside the frame 110 so as to divide the through hole TH. The cross member 150 includes three first auxiliary members 151 that connect the pair of first frame members 111A, 111B, and one second auxiliary member 152 that connects the pair of second frame members 112A, 112B. As will be described in detail later, the first auxiliary members 151 and the second auxiliary members 152 are engaged with each other at positions where they intersect.

[0064] 6 and 7, the first frame member 111B has a first hole 111g provided in the approximate center in the vehicle front-rear direction so as to face the inside (through hole TH). Note that in FIGS. 6 and 7, the first frame member 111B is used for explanation, but the first frame member 111A has a similar configuration. The first hole 111g is defined by a bottom surface 111h, a top surface 111i facing the bottom surface 111h, and two side surfaces 111j and 111k connecting the bottom surface 111h and the top surface 111i. In a cross section perpendicular to the vehicle width direction, the side surface 111j has a lower side surface 111j1 provided perpendicularly (i.e., along the vertical direction) and an upper side surface 111j2 inclined by an angle (second angle) θ2 from the vertical direction. Further, in a cross section perpendicular to the vehicle width direction, the side surface 111k has a lower side surface 111k1 that is provided vertically (i.e., along the vertical direction) and an upper side surface 111k2 that is inclined from the vertical direction by an angle (second angle) θ2. That is, the upper side surfaces 111j2, 111k2 are inclined so as to narrow downward in the vehicle vertical direction at the angle θ2 when viewed from the vehicle width direction. The upper side surfaces 111j2, 111k2 form a third inclined portion. For example, the angle θ2 can be 1 degree or more and 10 degrees or less.

[0065] The first auxiliary member 151 is an aluminum extrusion extending linearly in the vehicle width direction. In a cross section perpendicular to the vehicle width direction, the first auxiliary member 151 is hollow. The inside of the first auxiliary member 151 is partitioned in the vehicle up-down direction by a partition wall 151a. The first auxiliary member 151 includes a top wall 151b located at the upper part in the vehicle up-down direction, a bottom wall 151c facing the top wall 151b, and side walls 151d and 151e connecting both ends of the top wall 151b and the bottom wall 151c. In this embodiment, the side walls 151d and 151e are composed of upper side walls (fourth inclined portions) 151d1 and 151e1, middle side walls 151d2 and 151e2, and lower side walls (tenth inclined portions) 151d3 and 151e3. The middle side walls 151d2, 151e2 are provided vertically (i.e., along the vertical direction) in a cross section perpendicular to the vehicle width direction. The upper side walls 151d1, 151e1 are inclined at an angle θ2 from the vertical direction. In other words, the upper side walls 151d1, 151e1 are inclined so as to narrow downward in the vehicle vertical direction at an angle θ2 when viewed from the vehicle width direction. The lower side walls 151d3, 151e3 are inclined at an angle θ5 from the vertical direction. In other words, the lower side walls 151d3, 151e3 are inclined so as to narrow upward in the vehicle vertical direction at an angle θ5 when viewed from the vehicle width direction. For example, the angle θ5 can be 1 degree or more and 10 degrees or less.

[0066] The first auxiliary member 151 is longer than the distance between the pair of first skeleton members 111A, 111B, and both ends of the first auxiliary member 151 are inserted into the first hole portions 111g of the pair of first skeleton members 111A, 111B. At this time, the upper side surfaces 111k2, 111j2 and the upper side walls 151d1, 151e1 are in contact with each other. In other words, the upper side walls 151d1, 151e1 are aligned with the upper side surfaces 111k2, 111j2, respectively.

[0067] 8 and 9, the second frame member 112B has a second hole 112e provided in the approximate center in the vehicle width direction so as to face the inside (through hole TH). Note that in FIG. 8, the second frame member 112B is used for explanation, but the second frame member 112A has a similar configuration. The second hole 112e is defined by a bottom surface 112f, a top surface 112g facing the bottom surface 112f, and two side surfaces 112h, 112i connecting the bottom surface 112f and the top surface 112g. The side surface 112h is inclined from the vertical direction by an angle (third angle) θ3 in a cross section perpendicular to the vehicle front-rear direction. The side surface 112i is inclined from the vertical direction by an angle (third angle) θ3 in a cross section perpendicular to the vehicle front-rear direction. That is, the lower side surfaces 112h, 112i are inclined so as to narrow upward in the vehicle vertical direction at an angle θ3 when viewed from the vehicle width direction. The lower side surfaces 112h, 112i form a fifth inclined portion. For example, the angle θ3 can be equal to or greater than 1 degree and equal to or less than 10 degrees.

[0068] The second auxiliary member 152 is an aluminum extrusion extending linearly in the vehicle longitudinal direction. In a cross section perpendicular to the vehicle longitudinal direction, the second auxiliary member 152 is hollow. The interior of the second auxiliary member 152 is partitioned in the vehicle vertical direction by a partition wall 152a. The second auxiliary member 152 includes a top wall 152b located at the upper part in the vehicle vertical direction, a bottom wall 152c facing the top wall 152b, and side walls 152d, 152e connecting both ends of the top wall 152b and the bottom wall 152c. In this embodiment, the side walls 152d, 152e are composed of upper side walls (eighth inclined portion) 152d1, 152e1 and lower side walls (sixth inclined portion) 152d2, 152e2. The lower side walls 152d2, 152e2 are inclined from the vertical by an angle θ3 in a cross section perpendicular to the vehicle longitudinal direction. In other words, the lower side walls 152d2, 152e2 are inclined so as to narrow upward in the vehicle vertical direction at an angle θ3 when viewed from the vehicle front-rear direction. Also, the upper side walls 152d1, 152e1 are inclined from the vertical by an angle θ4 in a cross section perpendicular to the vehicle front-rear direction. In other words, the upper side walls 152d1, 152e1 are inclined so as to narrow downward in the vehicle vertical direction at an angle θ4 when viewed from the vehicle front-rear direction. For example, the angle θ4 can be greater than or equal to 1 degree and less than or equal to 10 degrees.

[0069] The second auxiliary member 152 is longer than the distance between the pair of second skeleton members 112A, 112B, and both ends of the second auxiliary member 152 are inserted into the second holes 112e of the pair of second skeleton members 112A, 112B. At this time, the lower side surfaces 112h, 112i and the lower side walls 152d2, 152e2 are in contact with each other. In other words, the lower side walls 152d2, 152e2 are aligned with the lower side surfaces 112h, 112i, respectively.

[0070] Referring to FIG. 7, the side surface 111f3 of the first engagement portion 111e is inclined at an angle (first angle) θ1 from the vertical direction. In other words, the side surface 111f3 is inclined so as to narrow downward in the vehicle vertical direction at an angle θ1 when viewed from the vehicle width direction. For example, the angle θ1 can be 1 degree or more and 10 degrees or less. In addition, the inclined surface 112d1 is inclined at an angle θ1 from the vertical direction in a cross section perpendicular to the vehicle width direction so as to narrow the through hole TH as it goes upward in the vehicle vertical direction. In other words, the inclined surface 112d1 is inclined so as to narrow downward in the vehicle vertical direction at an angle θ1 when viewed from the vehicle width direction. When the first engagement portion 111e and the second engagement portion 112b engage with each other, the side surface 111f3 of the first engagement portion 111e and the inclined surface 112d1 of the second framework member 112A are in surface contact with each other. In other words, the second engagement portion 112b includes an inclined surface 112d1 aligned with the side surface 111f3.

[0071] 6 and 10, the first auxiliary member 151 has a third engagement portion 151f at a substantially central portion in the vehicle width direction (i.e., a portion where the first auxiliary member 151 and the second auxiliary member 152 intersect). In other words, the third engagement portion 151f is aligned with the second auxiliary member 152 in the vehicle width direction. The third engagement portion 151f has a concave shape. In detail, the third engagement portion 151f has a recess 151g that is recessed downward in the vehicle up-down direction. The recess 151g is composed of a bottom surface 151g1 and side surfaces (seventh inclined portions) 151g2 and 151g3. The bottom surface 151g1 is composed of the partition wall 151a. That is, the first auxiliary member 151 has a closed space S1 (see FIG. 7) below the recess 151g in the vehicle up-down direction in a cross section perpendicular to the vehicle width direction. The side surfaces 151g2, 151g3 are inclined at an angle (fourth angle) θ4 from the vertical in a cross section perpendicular to the vehicle front-rear direction. In other words, the side surfaces 151g2, 151g3 are inclined so as to narrow downward in the vehicle up-down direction at the angle θ4 when viewed from the vehicle front-rear direction.

[0072] 8 and 11, the second auxiliary member 152 has a fourth engagement portion 152f at a portion where the first auxiliary member 151 and the second auxiliary member 152 intersect. In other words, the fourth engagement portion 152f is aligned with the first auxiliary member 151 in the vehicle longitudinal direction. The fourth engagement portion 152f has a concave shape. In detail, the fourth engagement portion 152f has a recess 152g that is recessed upward in the vehicle vertical direction. The recess 152g is composed of a top surface 152g1, upper side surfaces 152g2 and 152g3, and lower side surfaces (ninth inclined portion) 152g4 and 152g5. The top surface 152g1 is composed of the partition wall 152a. That is, the second auxiliary member 152 has a closed space S2 (see FIG. 9) above the recess 152g in the vehicle vertical direction in a cross section perpendicular to the vehicle longitudinal direction. The upper side surfaces 152g2, 152g3 are provided perpendicular to the top surface 152g1 (i.e., along the vertical direction). The lower side surfaces 152g4, 152g5 are connected to the upper side surfaces 152g2, 152g3, and are inclined at an angle (fifth angle) θ5 from the vertical direction in a cross section perpendicular to the vehicle width direction. In other words, the lower side surfaces 152g4, 152g5 are inclined so as to narrow upward in the vehicle vertical direction at the angle θ5 when viewed from the vehicle width direction.

[0073] 5, 10, and 11, the third engaging portion 151f and the fourth engaging portion 152f have shapes that engage with each other. In this embodiment, the recess 151g of the third engaging portion 151f and the recess 152g of the fourth engaging portion 152f engage with each other, thereby directly joining the first auxiliary member 151 and the second auxiliary member 152. Specifically, the side surfaces 151g2 and 151g3 of the third engaging portion 151f and the upper side walls 152d1 and 152e1 of the second auxiliary member 152 are in surface contact with each other (see FIG. 10). That is, the side surfaces 151g2 and 151g3 of the third engaging portion 151f and the upper side walls 152d1 and 152e1 of the second auxiliary member 152 are aligned with each other. Also, the lower side surfaces 152g4, 152g5 of the fourth engagement portion 152f and the lower side walls 151d3, 151e3 of the first auxiliary member 151 are in contact with each other (see FIG. 11). That is, the lower side surfaces 152g4, 152g5 of the fourth engagement portion 152f and the lower side walls 151d3, 151e3 of the first auxiliary member 151 are aligned. Note that only the portion of the second auxiliary member 152 aligned with the side surfaces 151g2, 151g3 of the third engagement portion 151f may be inclined at the angle θ4. Also, only the portion of the first auxiliary member 151 aligned with the lower side surfaces 152g4, 152g5 of the fourth engagement portion 152f may be inclined at the angle θ4.

[0074] In addition, in the present embodiment, a structure in which both the third engagement portion 151f and the fourth engagement portion 152f have a shape recessed in the vehicle vertical direction is exemplified, but the third engagement portion 151f and the fourth engagement portion 152f are not limited to this shape and may have any shape capable of joining the first auxiliary member 151 and the second auxiliary member 152. For example, a structure in which only one of the third engagement portion 151f and the fourth engagement portion 152f has a recessed shape may be used. The recessed shape is not limited to a shape recessed in the vehicle vertical direction, and may be a shape recessed in other directions. Also, an engagement structure other than a recessed shape may be used.

[0075] Referring to FIG. 4, the tray 120 is a bathtub-shaped member that accommodates the battery 30 (see FIG. 2). The tray 120 is made of, for example, an aluminum alloy plate. The tray 120 includes a flange 121 that extends in the horizontal direction (XY direction) at the outer edge, and a storage section 122 that is continuous with the flange 121 and has a concave shape. The storage section 122 is a portion that accommodates the battery 30, and is partially disposed within the through-hole TH of the frame 110. The storage section 122 has a bottom wall 122a that constitutes the bottom surface, and a peripheral wall 122b that is provided around the bottom wall 122a and defines an opening 122e on the opposite side to the bottom wall 122a. The peripheral wall 122b is pressed against the frame 110, as will be described in detail later.

[0076] The bottom wall 122a of the storage section 122 is formed with a protruding portion 122c having a shape complementary to the first auxiliary member 151, and a protruding portion 122d having a shape complementary to the second auxiliary member 152. The protruding portion 122c is a portion of the bottom wall 122a that protrudes partially upward and extends in the vehicle width direction. The protruding portion 122d is a portion of the bottom wall 122a that protrudes partially upward and extends in the vehicle front-rear direction. The details will be described later, but the protruding portion 122c is pressed against the first auxiliary member 151, and the protruding portion 122d is pressed against the second auxiliary member 152.

[0077] 3 again, in a state where the tray 120 and the frame 110 are combined, the flange 121 of the tray 120 is placed on the top surfaces 111l, 112j (see FIG. 4) of the frame 110, and the accommodation portion 122 of the tray 120 is disposed in the through hole TH of the frame 110. At this time, the overhanging portions 122c, 122d are disposed so as to partially cover the cross member 150. Although FIG. 4 shows a virtual exploded view for the purpose of explanation, the tray 120 is integrated in the combined state as shown in FIG. 3 by pressing the overhanging portions 122c, 122d against the cross member 150.

[0078] 2 again, the battery 30 is placed in the accommodation portion 122 of the tray 120. The accommodation portion 122 is sealed from above the battery 30 by the top cover 130, so that the battery 30 is stored in the battery case 100. This sealed structure prevents water from entering the battery case 100 from the outside. In particular, because the tray 120 is formed in a bathtub shape, there are no seams in the tray 120, and high sealing properties that can prevent water from entering from the road surface or the like can be ensured. In addition, a safety valve for adjusting the pressure inside the battery case 100 may be provided.

[0079] 2, the top cover 130 and the tray 120 are fixed to the frame 110 by being fastened together with screws. A floor panel 300 constituting the floor surface of the vehicle interior R and a floor cross member 400 extending in the vehicle width direction in the vehicle interior R are disposed above the top cover 130. In addition, an undercover 140 is disposed below the tray 120. The undercover 140 is screwed to both the frame 110 and the cross member 150, and supports the tray 120 from below.

[0080] A manufacturing method for the battery case 100 having the above configuration will be described with reference to Figures 12 to 15. Figures 13 to 15 show a cross section perpendicular to the vehicle width direction. In addition, in Figures 13 to 15, only one first auxiliary member 151 is shown for clarity of illustration.

[0081] 12, a flat-plate-shaped molded member 120, a pair of first skeletal members 111A, 111B, a pair of second skeletal members 112A, 112B, a first auxiliary member 151, and a second auxiliary member 152 are prepared. Then, the pair of first skeletal members 111A, 111B are arranged to extend in the vehicle front-rear direction, and both ends of the first auxiliary member 151 are inserted into the first hole portion 111g (see FIG. 6) to connect the pair of first skeletal members 111A, 111B. Next, the pair of second skeletal members 112A, 112B are arranged to extend in the vehicle width direction, and both ends of the second auxiliary member 152 are inserted into the second hole portion 112e (see FIG. 8) to connect the pair of second skeletal members 112A, 112B. Next, the pair of first skeletal members 111A, 111B and the pair of second skeletal members 112A, 112B are joined by mechanically engaging the first engagement portion 111e and the second engagement portion 112b (an example of a mechanical joining method) to form a frame 110 that has a rectangular frame shape when viewed from the top-bottom direction of the vehicle and defines a through hole TH on the inside (see Figure 4).

[0082] At this time, preferably, the pair of first skeletal members 111A and 111B are heated before both ends of the first auxiliary member 151 are inserted into the first hole portion 111g (see FIG. 6). This expands the size of the first hole portion 111g (see FIG. 6), making it easier to insert both ends of the first auxiliary member 151. In addition, the pair of first skeletal members 111A and 111B return to room temperature, thereby reducing the size of the first hole portion 111g (see FIG. 6), and the pair of first skeletal members 111A and 111B and the first auxiliary member 151 are firmly connected. As a modified example, the first auxiliary member 151 may be cooled before both ends of the first auxiliary member 151 are inserted into the first hole portion 111g (see FIG. 6). Furthermore, the pair of first skeleton members 111A, 111B may be heated before mechanically joining the pair of first skeleton members 111A, 111B and the pair of second skeleton members 112A, 112B. In this case, the first engaging portion 111b and the second engaging portion 112b are firmly engaged with each other, as described above. As a further modified example, the pair of first skeleton members 111A, 111B may be cooled before mechanically joining the pair of first skeleton members 111A, 111B and the pair of second skeleton members 112A, 112B.

[0083] 13, a molded member 120 is placed on a frame 110 and placed on a table 55. The same reference symbol 120 is used for both the molded member and the tray, which means that the member is in a molded state before molding and the tray is in a molded state after molding.

[0084] 14 and 15, pressure is applied to the molded member 120 from the opposite side to the frame 110 (i.e., from above), and the molded member 120 is pressed against the frame 110 to bulge in the through-hole TH. This causes the molded member 120 to deform into a bathtub-shaped tray 120 and to be pressed against the frame 110. At this time, the molded member 120 is also pressed against the first auxiliary member 151 and the second auxiliary member 152. As a result, the tray 120, the frame 110, the first auxiliary member 151, and the second auxiliary member 152 are integrated together.

[0085] In this embodiment, the pressurization of the molded member 120 is performed by a pressure molding method (rubber bulge method) using an elastic body. The pressure molding method refers to a method of molding a member by gas or liquid pressure. In this embodiment, a liquid pressure transmission elastic body (elastic body) 50 that can be elastically deformed by using the pressure of the liquid when the liquid is injected in the rubber bulge method is used. The liquid pressure transmission elastic body 50 may have a structure in which only the lower surface of a metal chamber containing a liquid such as water or oil is blocked with an elastic membrane. In such a liquid pressure transmission elastic body 50, the elastic membrane is deformed by adjusting the pressure of the liquid, and molding can be performed without the liquid coming into direct contact with the molded member 120.

[0086] 13 and 14, in this embodiment, the frame 110, the molded member 120, and the hydraulic pressure transmission elastic body 50 are stacked in this order on the table 55 and arranged so as to be in contact with each other. Next, pressurized liquid is injected into the hydraulic pressure transmission elastic body 50, so that the molded member 120 is pressurized from the opposite side of the frame 110 via the hydraulic pressure transmission elastic body 50 and pressed against the frame 110. Then, the hydraulic pressure transmission elastic body 50 is caused to bulge in the through hole TH, thereby deforming the molded member 120 into a bathtub-shaped tray. Preferably, the pressurization of the molded member 120 by the rubber bulge method is performed in a state in which the molded member 120 is heated and softened. In this case, the softening of the molded member 120 can further suppress cracking during molding of the tray 120.

[0087] Also, the hydraulic pressure transmitting elastic body 50 may be expanded twice in the through hole TH. That is, in the first expansion, pressure is applied to the molded member 120 from the opposite side to the frame 110, and the molded member 120 is pressed against the frame 110 to expand the hydraulic pressure transmitting elastic body 50 in the through hole TH. This causes the molded member 120 to deform into a tray 120 that is roughly bathtub-shaped. In the second expansion, pressure is applied to the molded member 120 from the opposite side to the frame 110, and the molded member 120 is pressed against the frame 110 to expand the hydraulic pressure transmitting elastic body 50 in the through hole TH. This causes the molded member 120 to deform into a bathtub-shaped tray 120 and to be pressed against the frame 110. In this case, the process of deforming the tray to fit the shape of the frame is performed twice, so that distortion is less likely to occur and moldability can be improved compared to the case of deforming in one step.

[0088] 15, when the pressurizing force is released after the molded member 120 is deformed into the bathtub-shaped tray 120, the hydraulic pressure transmitting elastic body 50 returns to its natural shape. Therefore, the hydraulic pressure transmitting elastic body 50 can be easily removed from the inside of the tray 120. After removing the hydraulic pressure transmitting elastic body 50, the under cover 140 is joined as shown in FIG. 2, the battery 30 is stored, and then the top cover 130 is joined to complete the battery case 100.

[0089] In this embodiment, an R shape (a shape with rounded corners) is provided on the inside of the upper part of the frame 110. This R shape is intended to encourage the flow of material into the inside of the molded member 120 during the above molding. However, due to the design of the extrusion material, etc., small R shapes may be provided in places other than the inside of the upper part of the frame 110. In the drawings, such small R shapes are omitted.

[0090] In this embodiment, negative angle molding is performed when the molded member 120 is molded into the bathtub-shaped tray 120. Here, the negative angle is a term often used in the field of molding using a mold, and indicates that the draft angle of the mold in the molded member is less than zero (negative). In this embodiment, the tray 120 is pressed against the inclined surfaces 112d1 of the pair of second frame members 112A, 112B by pressure from the hydraulic pressure transmitting elastic body 50, and a negative angle portion 122f1 is formed on the tray 120, in which a negative angle is formed from the bottom wall 122a of the tray 120 toward the inside in the horizontal direction toward the upper side in the vehicle vertical direction. Similarly, the tray 120 is pressed against the upper side walls 151d1, 151e1 of the first auxiliary member 151, and a negative angle portion 122f1 is formed on the tray 120, in which a negative angle is formed from the bottom wall 122a of the tray 120 toward the upper side in the vehicle vertical direction toward the horizontal direction (vehicle front-rear direction).

[0091] The battery case 100 and the manufacturing method thereof described above provide the following advantages.

[0092] Since the pair of first skeletal members 111A, 111B and the pair of second skeletal members 112A, 112B are joined by a mechanical joining method, and the first auxiliary member 151 and the second auxiliary member 152 are joined by a mechanical joining method, complicated welding is not required. Therefore, it is possible to suppress a decrease in the assembly accuracy of the frame 110 due to welding heat distortion, and the frame 110 and the cross member 150 can be easily configured. In addition, since the tray 120 is formed in a bathtub shape, there are no seams in the tray 120, and high sealing properties that can prevent water from entering from the road surface, etc. can be ensured. In addition, since the cross member 150 supports the frame 110 from the inside, high rigidity can be ensured.

[0093] Moreover, the pair of first frame members 111A, 111B and the pair of second frame members 112A, 112B are directly joined together by the engagement of the first engaging portion 111e and the second engaging portion 112b. This allows the frame 110 to be easily configured. Furthermore, accurate positioning is achieved by fitting with structural positional constraints, which improves dimensional accuracy and joining accuracy.

[0094] The recesses 111f, 112c recessed in the vehicle vertical direction are fitted together, thereby restricting the horizontal positions of the pair of first frame members 111A, 111B and the pair of second frame members 112A, 112B. Furthermore, the insertion portion 112k is inserted into the insertion hole 111m, so that the engagement can be prevented from being released. Furthermore, the bathtub-shaped tray 120 is disposed on the frame 110 from above, so that the first engagement portion 111e and the second engagement portion 112b can be covered by the tray 120. Therefore, the position in the vehicle vertical direction is also restricted, and the engagement can be prevented from being released.

[0095] Since the gap between the first engagement portion 111e and the second engagement portion 112b becomes smaller as they engage with each other, assembly becomes easier and rattling after assembly can be suppressed or prevented.

[0096] The configuration of inserting the first auxiliary members 151 into the first holes 111g is simple and low cost, and the connection between the pair of first frame members 111A, 111B by the first auxiliary members 151 can be specifically designed.

[0097] Since the gap between first hole portion 111g and first auxiliary member 151 becomes smaller as they engage with each other, assembly becomes easier and rattling after assembly can be suppressed or prevented.

[0098] The configuration of inserting the second auxiliary member 152 into the second hole portion 112e is simple and low cost, and the connection of the pair of second frame members 112A, 112B by the second auxiliary member 152 can be specifically designed.

[0099] Since the gap between second hole portion 112e and second auxiliary member 152 becomes smaller as they engage with each other, assembly becomes easier and rattling after assembly can be suppressed or prevented.

[0100] By joining first auxiliary member 151 and second auxiliary member 152, the rigidity of the entire frame 110 can be improved.

[0101] The horizontal positions of first auxiliary member 151 and second auxiliary member 152 are restricted by fitting the recesses recessed in the vehicle vertical direction into each other. Furthermore, because bathtub-shaped tray 120 is disposed on frame 110 from above, third engagement portion 151f and fourth engagement portion 152f can be covered by tray 120. Therefore, the positions in the vehicle vertical direction are restricted and the engagement can be prevented from being released.

[0102] Since the gap between the third engaging portion 151f and the fourth engaging portion 152f becomes smaller as they engage with each other, assembly becomes easier and rattling after assembly can be suppressed or prevented.

[0103] Since the top surfaces 111l and 112j are flush with each other, it is possible to suppress or prevent a gap from being generated between the frame 110 and the tray 120. This can improve the sealing performance.

[0104] Since the first partition wall 111c and the second partition wall 112a are configured to be at the same height, when a horizontal collision load is applied to the frame 110, the collision load can be transmitted to the entire frame via the first partition wall 111c and the second partition wall 112a. Therefore, the collision load can be absorbed by the entire frame 110, and the collision resistance can be improved.

[0105] Since the tray 120 is pressed against the frame 110, the frame 110 and the tray 120 can be easily integrated together without the need for welding.

[0106] Since the negative corner portions 122f1 and 122f2 are provided, even if an upward force is applied to the tray 120, the negative corner portions 122f1 and 122f2 are caught by the frame 110, so that it is possible to prevent the tray 120 from coming off the frame 110. In other words, it is possible to prevent the pressure contact between the tray 120 and the frame 110 from being released.

[0107] Since the first hole 111g expands when the pair of first skeletal members 111A, 111B is heated, or the first auxiliary member 151 contracts when it is cooled, the first auxiliary member 151 can be easily inserted into the first hole 111g. Furthermore, the pair of first skeletal members 111A, 111B or the first auxiliary member 151 can be firmly joined together when the pair of first skeletal members 111A, 111B or the first auxiliary member 151 returns to room temperature. Similarly, the pair of first skeletal members 111A, 111B and the pair of second skeletal members 112A, 112B can be easily and firmly joined together.

[0108] The use of the hydraulic pressure transmitting elastic body 50 facilitates the bulging deformation of the molded member 120 with respect to a complex shape such as that in which the first auxiliary member 151 is disposed. In other words, the amount of bulging of the molded member 120 can be increased, and the tray 120 can be firmly pressed against the frame 110.

[0109] 16, a preforming process may be performed using a preforming mold 51 before the molded member 120 is molded into a bathtub-shaped tray by the hydraulic pressure transmitting elastic body 50. In the preforming process, the molded member 120 is molded almost or completely into the shape of the bathtub-shaped tray 120. Therefore, the preforming mold 51 has a molding surface having a shape complementary to the shape of the tray 120 to be molded. The preforming mold 51 is made of metal, and is not used for performing the negative angle molding described above.

[0110] The process of deforming the tray 120 to fit the shapes of the frame 110 and the cross member 150 is performed at least twice, through the above-mentioned preforming and the subsequent main forming (forming of the hydraulic pressure transmitting elastic body 50). Therefore, compared to the case where the formed member 120 is deformed in one step, distortion is less likely to occur, and formability can be improved.

[0111] Second embodiment 17, the configuration of the battery case 100 according to the second embodiment of the present invention differs from that of the first embodiment in the following respects. The other configurations of this embodiment are similar to those of the first embodiment, and the same reference numerals are used for elements that are the same as or similar to those of the first embodiment. Note that in FIG. 17, only the joints between the first skeletal member 111B and the second skeletal member 112B are shown enlarged, but the other joints have the same configuration.

[0112] In the second embodiment, the battery case 100 further includes a joining member 114 for joining the pair of first frame members 111A, 111B and the pair of second frame members 112A, 112B.

[0113] The joint member 114 has a rectangular parallelepiped base 114a and a protruding portion 114b protruding from the base 114a. The protruding portion 114b includes four inner protruding pieces 114b1 and four outer protruding pieces 114b2 protruding farther from the base 114a than the four inner protruding pieces 114b1. When viewed from the vehicle up-down direction, the four outer protruding pieces 114b2 are located outside the four inner protruding pieces 114b1 in the vehicle width direction or outside the vehicle front-rear direction.

[0114] In the second embodiment, each of the pair of first skeleton members 111A, 111B does not have a first engagement portion 111e (see FIG. 5), and each of the pair of second skeleton members 112A, 112B does not have a second engagement portion 112b (see FIG. 5). In addition, both ends of each of the pair of first skeleton members 111A, 111B are cut obliquely so as to correspond to the shape of the joint member 114. Both ends of each of the pair of second skeleton members 112A, 112B are also cut obliquely so as to correspond to the shape of the joint member 114.

[0115] The four inner protruding pieces 114b1 and the four outer protruding pieces 114b2 are inserted into the pair of first skeleton members 111A, 111B and the pair of second skeleton members 112A, 112B. Therefore, when the pair of first skeleton members 111A, 111B, the pair of second skeleton members 112A, 112B, and the joint member 114 are assembled into the frame 110, only the base 114a of the joint member 114 is visible, and the four inner protruding pieces 114b1 and the four outer protruding pieces 114b2 are not visible.

[0116] The protrusion 114b is inserted into the pair of first skeleton members 111A, 111B, thereby mechanically joining the pair of first skeleton members 111A, 111B and the joining member 114. The protrusion 114b is inserted into the pair of second skeleton members 112A, 112B, thereby mechanically joining the pair of second skeleton members 112A, 112B and the joining member 114. In this manner, the pair of first skeleton members 111A, 111B and the pair of second skeleton members 112A, 112B are indirectly joined via the joining member 114.

[0117] In the second embodiment, the pair of first skeleton members 111A, 111B and the pair of second skeleton members 112A, 112B can be joined without performing complicated processing on the pair of first skeleton members 111A, 111B and the pair of second skeleton members 112A, 112B, which are extruded materials. In this manner, the mechanical joining of the pair of first skeleton members 111A, 111B and the pair of second skeleton members 112A, 112B includes not only a direct joining as in the first embodiment, but also an indirect joining as in the second embodiment.

[0118] 18, in the modified example of the second embodiment, both ends of a pair of first frame members 111A, 111B are cut perpendicular to the vehicle front-rear direction. Similarly, both ends of a pair of second frame members 112A, 112B are cut perpendicular to the vehicle width direction. Therefore, compared to the above embodiment, the pair of first frame members 111A, 111B and the pair of second frame members 112A, 112B can be manufactured more easily.

[0119] In this modification, the battery case 100 further includes a joining member 115 for joining the pair of first frame members 111A, 111B and the pair of second frame members 112A, 112B.

[0120] The joint member 115 has a base 115a in the shape of a circular sector. The joint member 115 also includes four protruding pieces 115b protruding from the base 115a. The joint member 115 is joined to the pair of first frame members 111A, 111B and the pair of second frame members 112A, 112B by a mechanical joining method at the four protruding pieces 115b. A cover 115c is attached to the upper surface of the base 115a to cover the upper surface. In addition, the surface of the base 115a located on the inside of the frame 110 and the surface located on the outside are curved surfaces 115d, 115e, respectively. In this way, the shape of the joint member 115 can be various. [Explanation of symbols]

[0121] 1 Electric vehicles 10 Front of vehicle 20 Center of the vehicle 30 Battery 50 Fluid pressure transmission elastic body (elastic body) 51 Preformed mold 55 units 55a Recess 100 Battery case for electric vehicles (battery case) 110 Frames 110a Upper 110b Inner corner 111A, 111B First frame member 111a First frame member body 111b First frame member reinforcement part 111b1 Bottom wall 111c Partition Wall (First Partition Wall) 111d Partition wall 111e 1st engagement part 111f Recess 111f1 Bottom 111f2 side 111f3 Side (first slope) 111g 1st hole 111h bottom 111i top 111j,111k side 111j1,111k1 Lower side 111j2,111k2 Upper side (3rd slope) 111l Top (1st top) 111m Insertion hole 112A, 112B Second frame member 112a Partition wall (Second partition wall) 112b Second engaging part 112c Recess 112c1 Top 112c2,112c3 side 112d Inside 112d1 Slope (second slope) 112d2 vertical plane 112e 2nd hole 112f Bottom 112g top 112h,112i Side (5th slope) 112j Top surface (second top surface) 112k plug 114 Joining materials 114a base 114b Protrusion 114b1 Inner protruding piece 114b2 Outer protruding piece 115 Joint materials 115a base 115b Projecting piece 115c cover 115d, 115e Curved surface 120 Tray (molded part) 121 Flange 122 Storage unit 122a Bottom wall 122b Peripheral wall 122c,122d Overhang 122e opening 122f1,122f2 Negative corner 130 Top cover 140 Undercover 150 Cross member 151 1st auxiliary member (auxiliary member) 151a Partition wall 151b Top wall 151c bottom wall 151d,151e side wall 151d1,151e1 Upper side wall (4th slope) 151d2,151e2 Middle side wall 151d3,151e3 Lower side wall (10th slope) 151f 3rd engaging part 151g Concave 151g1 Bottom 151g2,151g3 Side (7th slope) 152 Second auxiliary member 152a Partition wall 152b Top wall 152c bottom wall 152d,152e side wall 152d1,152e1 Upper side wall (8th slope) 152d2,152e2 Lower side wall (6th slope) 152f 4th engagement part 152g Concave 152g1 Top 152g2,152g3 Upper side 152g4,152g5 Lower side (9th slope) 200 Rocker member 300 Floor Panel 400 floor cross member

Claims

1. A frame that is configured in a rectangular frame shape when viewed from the top-bottom direction of the vehicle and defines a space therein; A cross member disposed inside the frame so as to divide the space; a bathtub-shaped tray that houses a battery and is positioned at least partially within the space of the frame; Equipped with The frame includes a pair of first skeletal members which are made of aluminum extrusions and extend in a vehicle front-rear direction, and a pair of second skeletal members which are made of aluminum extrusions and extend in a vehicle width direction, the cross member includes a first auxiliary member which is an aluminum extrusion and connects the pair of first frame members, and a second auxiliary member which is an aluminum extrusion and connects the pair of second frame members, the pair of first skeletal members and the pair of second skeletal members are mechanically joined together, the first auxiliary member and the second auxiliary member are mechanically joined; The pair of first skeletal members each have a first engagement portion, The pair of second skeletal members each have a second engagement portion, At least one of the first engagement portion and the second engagement portion has a concave shape, A battery case for an electric vehicle, wherein the pair of first skeletal members and the pair of second skeletal members are directly joined together by the first engagement portion and the second engagement portion being engaged with each other.

2. The second engagement portion has a recessed portion that is recessed upward in the vehicle vertical direction, and an insertion portion that constitutes a part of the recessed portion and is protruding downward in the vehicle vertical direction, 2. The battery case for an electric vehicle according to claim 1, wherein the first engagement portion has a recess that is recessed downward in the vehicle up-down direction, and an insertion hole that is aligned with the insertion portion and into which the insertion portion is inserted.

3. The recess of the first engagement portion includes a first inclined portion that is inclined so as to narrow at a first angle downward in the vehicle up-down direction when viewed from the vehicle width direction, 3. The battery case for an electric vehicle according to claim 2, wherein the second engagement portion has a second inclined portion that is aligned with the first inclined portion and inclined so as to narrow at the first angle downward in the vehicle up-down direction when viewed from the vehicle width direction.

4. A frame having a rectangular shape when viewed from the top-bottom direction of the vehicle and defining a space therein; A cross member disposed inside the frame so as to divide the space; a bathtub-shaped tray that houses a battery and is positioned at least partially within the space of the frame; Equipped with The frame includes a pair of first skeletal members which are made of aluminum extrusions and extend in a vehicle front-rear direction, and a pair of second skeletal members which are made of aluminum extrusions and extend in a vehicle width direction, the cross member includes a first auxiliary member which is an aluminum extrusion and connects the pair of first frame members, and a second auxiliary member which is an aluminum extrusion and connects the pair of second frame members, the pair of first skeletal members and the pair of second skeletal members are mechanically joined together, the first auxiliary member and the second auxiliary member are mechanically joined; the pair of first skeletal members each have a first hole portion provided facing the space, a battery case for an electric vehicle, wherein both ends of the first auxiliary member are inserted into the first hole portion.

5. the pair of first skeletal members each have a first hole portion provided facing the space, The battery case for an electric vehicle according to claim 1 , wherein both ends of the first auxiliary member are inserted into the first hole portion.

6. The first hole portion includes a third inclined portion that is inclined so as to narrow at a second angle downward in the vehicle vertical direction when viewed from the vehicle width direction, 6. The battery case for an electric vehicle according to claim 5, wherein the first auxiliary member has a fourth inclined portion that is aligned with the third inclined portion and inclined so as to narrow at the second angle downward in the vehicle up-down direction when viewed from the vehicle width direction.

7. the pair of second skeletal members each have a second hole portion provided facing the space, The battery case for an electric vehicle according to claim 5 , wherein both ends of the second auxiliary member are inserted into the second hole portion.

8. the second hole portion includes a fifth inclined portion inclined so as to narrow at a third angle upward in the vehicle up-down direction as viewed from the vehicle front-rear direction, 8. The battery case for an electric vehicle according to claim 7, wherein the second auxiliary member has a sixth inclined portion that is aligned with the fifth inclined portion and inclined so as to narrow at the third angle upward in the vehicle up-down direction when viewed from the vehicle fore-and-aft direction.

9. the first auxiliary member has a third engagement portion, the second auxiliary member has a fourth engagement portion, At least one of the third engagement portion and the fourth engagement portion has a concave shape, The battery case for an electric vehicle according to claim 7 , wherein the first auxiliary member and the second auxiliary member are joined together by the third engagement portion and the fourth engagement portion being engaged with each other.

10. The third engagement portion has a recessed portion that is recessed downward in the vehicle up-down direction, The battery case for an electric vehicle according to claim 9 , wherein the fourth engagement portion has a recessed portion that is recessed upward in the vehicle up-down direction.

11. the third engagement portion includes a seventh inclined portion inclined so as to narrow at a fourth angle downward in the vehicle up-down direction as viewed from the vehicle front-rear direction, 11. The battery case for an electric vehicle according to claim 10, wherein the second auxiliary member has an eighth inclined portion that is aligned with the seventh inclined portion and inclined so as to narrow at the fourth angle downward in the vehicle up-down direction when viewed from the vehicle front-rear direction.

12. the fourth engagement portion includes a ninth inclined portion inclined so as to narrow at a fifth angle upward in the vehicle vertical direction as viewed from the vehicle width direction, 11. The battery case for an electric vehicle according to claim 10, wherein the first auxiliary member has a tenth inclined portion that is aligned with the ninth inclined portion and inclined so as to narrow at the fifth angle upward in the vehicle vertical direction when viewed from the vehicle width direction.

13. the pair of first framework members are located at the uppermost position in the vehicle up-down direction and have a first top surface extending in a horizontal direction, the pair of second framework members are located at the uppermost position in the vehicle up-down direction and have second top surfaces extending in a horizontal direction, The battery case for an electric vehicle according to claim 1 , wherein the first top surface and the second top surface are flush with each other.

14. The pair of first framework members are cylindrical and have an interior partitioned in the vehicle up-down direction by a first partition wall extending in a horizontal direction, The pair of second framework members are cylindrical and have an interior partitioned in the vehicle up-down direction by a second partition wall extending in a horizontal direction, The battery case for an electric vehicle according to claim 1 , wherein the first partition wall and the second partition wall are disposed at the same height in the vehicle up-down direction.

15. A battery case for an electric vehicle as described in any one of claims 1 to 4, wherein the tray is pressed against the frame.

16. 5. The battery case for an electric vehicle according to claim 1, wherein a negative corner portion is provided in which a negative angle is formed at least partially inward in the horizontal direction from a bottom wall of the tray upward in the vehicle up-down direction.

17. A flat-plate-shaped formed member, a pair of first skeletal members which are aluminum extrusions, a pair of second skeletal members which are aluminum extrusions, a first auxiliary member which is an aluminum extrusion, and a second auxiliary member which is an aluminum extrusion are prepared; The pair of first skeletal members each have a first engagement portion, The pair of second skeletal members each have a second engagement portion, At least one of the first engagement portion and the second engagement portion has a concave shape, The pair of first framework members are disposed so as to extend in a front-rear direction of the vehicle, The pair of second framework members are disposed so as to extend in a vehicle width direction, a frame having a rectangular shape when viewed from the top-bottom direction of the vehicle and defining a space therein is formed by mechanically joining the pair of first skeletal members and the pair of second skeletal members by engaging the first engaging portions with the second engaging portions, and a cross member is formed by mechanically joining the first auxiliary member that connects the pair of first skeletal members to the second auxiliary member that connects the pair of second skeletal members so as to divide the space; The molded member is placed on the frame and the cross member, Pressure is applied to the formed member from the side opposite to the frame and the cross member, and the formed member is pressed against the frame and the cross member to bulge within the space, thereby deforming the formed member into a bathtub-shaped tray and pressing it against the frame and the cross member. A method for manufacturing a battery case for an electric vehicle, comprising:

18. A method of forming a molded member having a flat shape, a pair of first skeletal members which are aluminum extrusions, a pair of second skeletal members which are aluminum extrusions, a first auxiliary member which is an aluminum extrusion, and a second auxiliary member which is an aluminum extrusion, a frame having a rectangular shape when viewed from the top-bottom direction of the vehicle and defining a space therein, the frame being configured by mechanically joining the pair of first framework members and the pair of second framework members; the pair of first skeletal members each have a first hole portion provided facing the space, The pair of first framework members are disposed so as to extend in a front-rear direction of the vehicle, The pair of second framework members are disposed so as to extend in a vehicle width direction, a cross member is formed by mechanically joining the first auxiliary member that connects the pair of first frame members and the second auxiliary member that connects the pair of second frame members so as to divide the space, and both ends of the first auxiliary member are inserted into the first hole portion; The molded member is placed on the frame and the cross member, Pressure is applied to the formed member from the side opposite to the frame and the cross member, and the formed member is pressed against the frame and the cross member to bulge within the space, thereby deforming the formed member into a bathtub-shaped tray and pressing it against the frame and the cross member. A method for manufacturing a battery case for an electric vehicle, comprising:

19. Further providing an elastic body into which a liquid is injected; The elastic body is disposed so as to be in contact with the workpiece, Pressurized liquid is injected into the elastic body to apply pressure to the molded member from the side opposite the frame and the cross member, forcing the molded member against the frame and the cross member and causing it to bulge within the space, thereby deforming the molded member into a bathtub-shaped tray and pressing it against the frame and the cross member. The method for manufacturing an electric vehicle battery case according to claim 17 or 18, further comprising:

20. The method for manufacturing a battery case for an electric vehicle according to claim 19, further comprising performing preforming using a preforming mold before the molded member is deformed and pressed by the elastic body.

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