Vehicle understructure

Abstract

The battery capacity is increased while ensuring energy absorption capabilities during side collisions. [Solution] The vehicle's understructure includes a side sill 20 having a closed cross-section located at the side end of the floor panel 30 in the vehicle width direction and extending in the vehicle longitudinal direction, a battery housing 4 located below the floor panel and having a battery 41 housed in a housing space 40, and fastening parts 6 for fastening the battery housing to the lower part of the side sill, wherein the fastening parts are located in the vehicle width direction at a position that coincides with the cross-sectional center C of the side sill, or outward from the cross-sectional center in the vehicle width direction.

Description

Technical Field

[0001] The technology disclosed herein relates to a lower structure of a vehicle.

Background Art

[0002] Patent Document 1 describes a conventional vehicle body lower structure. The vehicle body lower structure includes a battery pack that houses a battery under a floor panel. A battery pack frame is attached to a side wall of the battery pack. The battery pack frame has a fixing portion and a frame main body. The fixing portion is fastened to a side sill inner at a lower portion of a side sill composed of the side sill inner and a side sill outer. The frame main body rises along an inner wall of the side sill on the inner side in the vehicle width direction relative to the side sill, and is joined to the side wall of the battery pack.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of Invention

Problem to be Solved by the Invention

[0004] In the conventional vehicle body lower structure, the side sill and the battery pack frame are arranged side by side in the vehicle width direction. Since the battery pack is located on the inner side in the vehicle width direction relative to the battery pack frame, the length in the vehicle width direction of the battery pack between the battery pack frames disposed on the left and right in the vehicle width direction is reduced. The conventional vehicle body lower structure limits the capacity of the battery pack that can be mounted on the vehicle.

[0005] In the conventional vehicle body lower structure, for example, it is conceivable to reduce the width of the battery pack frame in the vehicle width direction. If the width of the battery pack frame is reduced, the battery pack can be expanded outward in the vehicle width direction by that amount.

[0006] The battery pack frame, along with the side sills, has the function of absorbing energy during side collisions. If the width of the battery pack frame is narrowed, the amount of energy that can be absorbed decreases. From the perspective of avoiding the input of collision loads to the battery pack, it is difficult to narrow the width of the battery pack frame.

[0007] The technology disclosed herein increases the battery capacity while ensuring energy absorption during side collisions. [Means for solving the problem]

[0008] The technology disclosed herein relates to the understructure of a vehicle. This understructure of a vehicle is: A side sill having a closed cross-section is located at the side end of the floor panel in the vehicle width direction and extends in the vehicle longitudinal direction, A battery housing located beneath the floor panel and containing a battery housed in a storage space, The battery housing is fastened to the lower part of the side sill, The fastening portion is located in the vehicle width direction at a position that coincides with the center of the cross-section of the side sill, or at a position that is outside the center of the cross-section in the vehicle width direction.

[0009] In the understructure of this vehicle, the fastening points are located either at a position that coincides with the cross-sectional center of the side sill in the vehicle width direction, or outside the cross-sectional center in the vehicle width direction, to fasten the side sill and the battery housing. The cross-sectional center may be the geometric center of the cross-section of the side sill.

[0010] A portion of the battery housing is located at least outward in the vehicle width direction from the fastening portion. Since the fastening portion is located near the outside of the side sill in the vehicle width direction, the outer end of the battery housing in the vehicle width direction is outside the fastening portion and close to the outer end of the side sill in the vehicle width direction.

[0011] When an initial collision load is applied to the side sill during a side collision, an initial collision load is also applied to the battery housing at the same time, or substantially at the same time.

[0012] Furthermore, after the initial collision load is applied, the side sills and battery housing absorb energy in parallel.

[0013] As a result, the understructure of the vehicle can shorten the energy absorption stroke in response to load input during a side collision.

[0014] Because the energy absorption stroke between the side sill and the battery housing is short, the battery housing space can be expanded in the vehicle width direction. This expansion of housing space allows for an increase in the battery's mounting capacity.

[0015] Therefore, the vehicle's understructure can increase the battery capacity while ensuring energy absorption during side collisions.

[0016] The battery housing has a frame located on the outer edge of the battery housing in the vehicle width direction and extending in the vehicle longitudinal direction, and forming the housing space on the inside in the vehicle width direction. The fastening portion may fasten the frame to the lower part of the side sill.

[0017] During a side collision, the impact load is applied to both the side sill and the frame. If the frame has high energy absorption capabilities, the vehicle's understructure can further shorten the energy absorption stroke during a side collision. This structure is advantageous for increasing the battery capacity.

[0018] The inner end of the side sill in the vehicle width direction may be located at the same position as the inner end of the frame in the vehicle width direction, or it may be located further out in the vehicle width direction than the inner end of the frame.

[0019] The fact that the inner end of the side sill in the vehicle width direction is at the same position as the inner end of the frame in the vehicle width direction means that the frame is not located further inward in the vehicle width direction than the side sill. That is, since the frame is positioned on the outer side in the vehicle width direction, the battery accommodation space can be expanded in the vehicle width direction.

[0020] Furthermore, if the inner end of the side sill in the vehicle width direction is positioned further outward in the vehicle width direction than the inner end of the frame in the vehicle width direction, the side sill has a narrow width in the vehicle width direction, which is advantageous for improving the ease of getting on and off the vehicle.

[0021] The outer end of the frame in the vehicle width direction may be at substantially the same position as the outer end of the side sill in the vehicle width direction with respect to the vehicle width direction.

[0022] If the outer end of the frame and the outer end of the side sill are at substantially the same position, both the side sill and the frame can receive the initial collision load at the time of a side collision. Since both the side sill and the frame receive the load from the initial stage of the collision, it is advantageous for shortening the energy absorption stroke.

[0023] The lower structure of the vehicle may further include a jack-up attachment mounted on the lower surface of the frame.

[0024] The vehicle may receive a jack-up load via the frame.

[0025] The jack-up attachment may have a fixing portion that penetrates the frame in the vertical direction and is fixed to the lower portion of the side sill.

[0026] The jack-up load is input to the side sill via the fixing portion of the jack-up attachment. The frame and the side sill can ensure the required rigidity against the jack-up load.

[0027] The frame may be an extruded material of an aluminum alloy.

[0028] Extruded aluminum alloys are suitable for use in battery housings due to their lightweight properties, corrosion resistance, and heat dissipation.

[0029] Although aluminum alloy extruded materials are relatively low in rigidity, the necessary rigidity against jack-up loads can be ensured by both the side sills and the frame.

[0030] The side sill has an inner and an outer that are joined in the vehicle width direction, The fastening portion may be fastened to the outer part.

[0031] The outer part is the relatively outer portion of the side sill in the vehicle width direction. Because the fastening portion is fastened to the outer part, the outer end of the frame in the vehicle width direction is located close to the outer end of the side sill in the vehicle width direction. The side sill and frame can receive the initial collision load and absorb energy in parallel. The energy absorption stroke in response to the load input can be further shortened.

[0032] The fastening portion may include a collar interposed between the lower part of the side sill and the frame, and a bolt inserted into the collar and fastening the frame and the side sill.

[0033] The collar of the fastening portion may be located in a position that coincides with the center of the cross-section of the side sill, or it may be located outside the center of the cross-section in the vehicle width direction. [Effects of the Invention]

[0034] The aforementioned understructure of the vehicle can increase the battery capacity while ensuring energy absorption during side collisions. [Brief explanation of the drawing]

[0035] [Figure 1] Figure 1 shows a vehicle to which the substructure disclosed herein is applied. [Figure 2]Figure 2 is a cross-sectional view taken along line II-II in Figure 1. [Figure 3] Figure 3 is a cross-sectional view taken along line III-III in Figure 1. [Figure 4] Figure 4 is a diagram comparing the stroke amount under collision load for a conventional substructure and the substructure disclosed herein. [Figure 5] Figure 5 shows a modified example of the substructure. [Figure 6] Figure 6 shows a modified example of the substructure. [Modes for carrying out the invention]

[0036] The following describes embodiments of the vehicle's understructure with reference to the drawings. The vehicle understructure described here is illustrative. The vehicle understructure described here relates to a vehicle in which the battery is mounted under the floor.

[0037] Figure 1 shows vehicle 1 to which the substructure disclosed herein is applied. The upper part of Figure 1 is a side view of the lower part of vehicle 1, viewed from the left, and the lower part is a bottom view of the underside of vehicle 1, viewed from below. Figure 2 is a cross-sectional view taken along line II-II of Figure 1, and Figure 3 is a cross-sectional view taken along line III-III of Figure 1.

[0038] In each diagram, Fr indicates the front of vehicle 1, Rr indicates the rear of vehicle 1, Rt indicates the right side of vehicle 1, and Lt indicates the left side of vehicle 1. The left-right direction of vehicle 1 is the vehicle width direction, In indicates the inward direction in the vehicle width direction, and Out indicates the outward direction in the vehicle width direction. Up indicates the top of vehicle 1, and Lw indicates the bottom of vehicle 1.

[0039] The understructure of vehicle 1 includes side sills 20. The side sills 20 are located on the right and left sides of the floor panel 30 in the vehicle width direction. The floor panel 30 extends in the vehicle longitudinal direction and in the vehicle width direction to form the floor of the passenger compartment.

[0040] The side sill 20 extends continuously in the longitudinal direction of the vehicle on both the right and left sides of the floor panel 30.

[0041] As shown in Figure 2 or Figure 3, the side sill 20 has an inner 21 and an outer 22. The inner 21 and the outer 22 are joined to each other, aligned in the vehicle width direction. The side sill 20 has a closed cross-section formed by the inner 21 and the outer 22.

[0042] More specifically, the inner 21 has a first flange 211 and a second flange 212, and as a whole has a lateral hat shape. The outer 22 has a third flange 223 and a fourth flange 224, and as a whole has a lateral hat shape. The inner 21 and outer 22 are made of, for example, steel plate that has been processed into a hat shape.

[0043] The first flange 211 and the third flange 223 are joined to each other at the upper part of the side sill 20, facing each other in the vehicle width direction. The second flange 212 and the fourth flange 224 are joined to each other at the lower part of the side sill 20, facing each other in the vehicle width direction. The joining position of the second flange 212 and the fourth flange 224 is shifted inward in the vehicle width direction compared to the joining position of the first flange 211 and the third flange 223. The joining position of the second flange 212 and the fourth flange 224 is located near the inner wall 201 of the side sill 20 in the vehicle width direction. The inner wall 201 is a side wall of the side sill 20 formed by the inner 21, and is a side wall located inward in the vehicle width direction of the side sill 20.

[0044] The outer wall 202 of the side sill 20 is formed by the outer 22, and the lower wall 203 of the side sill 20 is also substantially formed by the outer 22. The outer wall 202 is a side wall located outward in the vehicle width direction of the side sill 20. The lower wall 203 is a wall that constitutes the lower part of the side sill 20. The upper wall 204 of the side sill 20 is formed by the inner 21 and the outer 22. The upper wall 204 is a wall that constitutes the upper part of the side sill 20. The side end of the floor panel 30 in the vehicle width direction is joined to the inner 21 of the upper wall 204.

[0045] The height H2 of the outer 22 is higher than the height H1 of the inner 21. The side sill 20 can ensure high rigidity.

[0046] Reference numeral 31 denotes a cross member 31. The cross member 31 extends in the vehicle width direction along the lower surface of the floor panel 30. The vehicle width end of the cross member 31 is joined to the inner wall 201 of the side sill 20.

[0047] The understructure of vehicle 1 includes a battery housing 4. The battery housing 4 is located beneath the floor panel 30.

[0048] The battery housing 4 has a battery 41 housed in a housing space 40. The battery 41 here is a battery module containing multiple battery cells. As shown in Figure 1, the battery housing 4 has multiple batteries 41. The multiple battery housings 4 are arranged in the vehicle's longitudinal and vehicle width directions.

[0049] The number of batteries 41 housed in the housing space 40 is not limited to a specific number. Furthermore, the battery module may be omitted, and the battery cells may be directly housed in the housing space 40.

[0050] The battery housing 4 has a frame 5. The frame 5 is located at the right and left edges, which are the outer edges of the battery housing 4 in the vehicle width direction. The frame 5 extends continuously in the vehicle longitudinal direction from the front end to the rear end of the side sill 20. The frame 5 forms a housing space 40 on the inside in the vehicle width direction.

[0051] The cross-section of the frame 5 has a horizontal T-shape. The frame 5 has a main body 51. The main body 51 has an inner surface 511 that extends vertically and in the vehicle's front-rear direction. The inner surface 511 forms a housing space 40. The height of the main body 51 is approximately the same as the height of the battery 41 housed in the housing space 40.

[0052] A cover 42 is attached to the upper part of the main body 51. The cover 42 extends in the longitudinal and width directions of the vehicle, forming the upper part of the storage space 40. The central part of the cover 42 is positioned higher than the peripheral part, closer to the floor panel 30, relative to the outer edge of the cover 42, that is, the outer edge that is attached to the upper part of the main body 51. Since the storage space 40 expands in the vertical direction, it is advantageous for increasing the mounting capacity of the battery 41.

[0053] A base 43 is attached to the lower part of the main body 51. The base 43 extends in the vehicle's longitudinal and vehicle width directions, forming the lower part of the storage space 40. The battery 41 is placed on the base 43. The battery 41 is also supported by a bracket 53 fixed to the inner surface 511 of the main body 51.

[0054] A seal 44 is interposed between the main body 51 and the cover 42, and between the main body 51 and the base 43. The storage space 40 is a sealed space.

[0055] The frame 5 has an extension portion 52. The extension portion 52 protrudes outward in the vehicle width direction from the outer surface 512 of the main body portion 51. The extension portion 52 is located below the side sill 20.

[0056] The length of the extension portion 52 in the vehicle width direction is longer than the length of the main body portion 51 in the vehicle width direction. The length of the extension portion 52 in the vehicle width direction is the same as or approximately the same as the width of the side sill 20 in the vehicle width direction. Most of the main body portion 51 is located inward in the vehicle width direction compared to the side sill 20.

[0057] The extension portion 52 is located near the center of the main body portion 51 in the height direction. The height of the extension portion 52 is lower than the height of the main body portion 51. In the vertical direction, the extension portion 52 is located near the lower ends of the second flange 212 and the fourth flange 224. The upper part of the main body portion 51 overlaps with the second flange 212 and the fourth flange 224 in the vertical direction.

[0058] The extension 52 also extends continuously in the longitudinal direction of the vehicle from the front end to the rear end of the side sill 20.

[0059] The frame 5 is made of, for example, an extruded aluminum alloy. The main body 51 and the extended portion 52 are integrally molded. The frame 5 has multiple closed cross-sections inside. As will be described later, the frame 5 has rigidity against impact loads from the side and can also ensure the necessary amount of energy absorption. Note that the cross-sectional shape of the frame 5 shown in the figure is just one example.

[0060] As shown in Figure 1, the battery housing 4 also includes frames 54 located at the front and rear edges of the battery housing 4 in the vehicle's longitudinal direction. These frames 54 extend in the vehicle width direction from the right frame 5 to the left frame 5, forming a storage space 40.

[0061] The lower structure of vehicle 1 includes fastening parts 6. The fastening parts 6 fasten the battery housing 4 to the lower part of the side sill 20. More specifically, the fastening parts 6 fasten the extended portion 52 of the frame 5 to the lower wall 203 of the side sill 20. The fastening parts 6 fasten the frame 5 to the lower part of the side sill 20 at multiple locations spaced apart in the longitudinal direction of the vehicle.

[0062] The fastening portion 6 has a collar 61. The collar 61 is joined to the lower wall 203 of the side sill 20 and extends downward from the lower wall 203. The lower end of the collar 61 is inserted from above into a hole formed in the extended portion 52 of the frame 5.

[0063] The fastening portion 6 has a bolt 62. The bolt 62 is inserted into the collar 61 from the lower surface of the extension portion 52 and penetrates the lower wall 203 of the side sill 20. By screwing a nut 63 onto the bolt 62, the extension portion 52 is supported by the lower wall 203 of the side sill 20, i.e., the outer 22.

[0064] As shown in Figure 3, the understructure of vehicle 1 is equipped with a jack-up attachment 70. The jack-up attachment 70 constitutes the jack-up point when jacking up vehicle 1 (see also Figure 1).

[0065] The jack-up attachment 70 is mounted on the underside of the extension portion 52 of the frame 5. The jack-up attachment 70 also has a fixing portion 71. The fixing portion 71 extends upward from the top surface of the jack-up attachment 70 and penetrates the extension portion 52 in the vertical direction. The upper end of the fixing portion 71 is fixed to the lower wall 203 of the side sill 20 by a bolt 72.

[0066] As shown in Figure 2, in this substructure, the entire side sill 20 overlaps with the frame 5 in the vehicle width direction (see Wf in Figure 2). In other words, the side sill 20 does not protrude outward in the vehicle width direction beyond the frame 5. The side sill 20 and the frame 5 substantially overlap in the vertical direction.

[0067] Because the side sill 20 does not protrude outward in the vehicle width direction beyond the frame 5, both the vertically overlapping side sill 20 and frame 5 receive the initial impact load during a side collision. Furthermore, since the side sill 20 and frame 5 substantially overlap vertically, the side sill 20 and frame 5 absorb energy in parallel.

[0068] Figure 4 is a diagram comparing a conventional substructure with the substructure disclosed herein. Figure 401 at the top of Figure 4 schematically shows a conventional substructure, while Figure 403 at the bottom schematically shows the substructure disclosed herein.

[0069] In conventional understructures, the side sills are located outward in the vehicle width direction compared to the battery housing frame. The side sills and frame are aligned in the vehicle width direction. The battery housing space is formed inside the frame in the vehicle width direction.

[0070] When a side impact load is applied to a vehicle with a conventional understructure, only the side sill bears the initial impact load, as shown in the load-stroke graph 402. At this time, the stroke of the understructure is determined solely by the stiffness of the side sill, and therefore the stroke relative to the load is relatively large.

[0071] Then, after the side sills have collapsed and absorbed the energy of the collision load, the frame begins to absorb the energy of the collision load.

[0072] In conventional substructures, only the side sills bear the initial collision load, and the side sills and frame absorb energy in series. Conventional substructures (see solid line in Graph 402) experience energy absorption losses in the initial stages of a collision compared to the substructure disclosed here (see dashed line in Graph 402). Conventional substructures require a longer stroke to compensate for energy absorption losses (see white arrow in Graph 402). To secure a longer stroke, conventional substructures could not expand the battery housing space outward in the vehicle width direction.

[0073] In contrast, in the substructure disclosed herein, as described above, both the vertically overlapping side sills 20 and frame 5 receive the initial collision load. Furthermore, the side sills 20 and frame 5 absorb energy in parallel from the initial stages of the collision. As shown in Graph 404, since there is no energy absorption loss in the initial stages of the collision, the substructure disclosed herein can shorten the energy absorption stroke in response to the input load compared to conventional substructures. As a result, the battery housing space 40 in the disclosed substructure can be expanded outward in the vehicle width direction (see the arrow Ws in Figure 2).

[0074] The expansion of the storage space 40 makes it possible to increase the mounting capacity of the battery 41 of the vehicle 1. The lower structure of the vehicle 1 disclosed herein, with its vertically aligned side sills 20 and frame 5, can increase the mounting capacity of the battery 41 while ensuring energy absorption during side collisions.

[0075] Furthermore, as shown in Figure 2, the outer end of the extended portion 52 of the frame 5 is at approximately the same position as the outer wall 202 of the side sill 20 in the vehicle width direction. This allows both the side sill 20 and the frame 5 to receive the initial collision load during a side collision. Since both the side sill 20 and the frame 5 receive the load from the initial stage of the collision, it is advantageous in shortening the energy absorption stroke.

[0076] Furthermore, the position of the outer end of the extension portion 52 and the outer wall 202 of the side sill 20 are not limited to being exactly the same, and some deviation is permissible. The outer end of the extension portion 52 may be located either inward or outward in the vehicle width direction compared to the position of the outer wall 202 of the side sill 20.

[0077] Furthermore, the main body 51 of the frame 5 has approximately the same height as the battery 41. Because the main body 51 is relatively tall, it can contribute to ensuring high rigidity in the frame 5.

[0078] On the other hand, the extension portion 52 has a lower height than the main body portion 51. Because the extension portion 52, which is located below the side sill 20, is low in height, the battery housing 4 can be brought closer to the side sill 20 and the floor panel 30. This makes it possible to increase the vertical size of the battery housing space 40 while keeping the vehicle height down.

[0079] Furthermore, when a collision load is applied, the main body 51, which is relatively taller, supports the extension 52, which is shorter. This ensures high rigidity for the frame 5 as a whole and is also advantageous for energy absorption.

[0080] Furthermore, since the extension portion 52 is located in the center of the outer surface 512 of the main body portion 51 in the height direction, the frame 5 can exhibit stable deformation behavior during a side collision. The extension portion 52 may also be located at the upper or lower end of the outer surface 512 of the main body portion 51 in the height direction. The cross-section of the frame 5 may have an L-shape.

[0081] The extension portion 52 extends continuously in the longitudinal direction of the vehicle from the front end to the rear end of the side sill 20, below the side sill 20. Regardless of where the collision load is applied to the side of the vehicle 1, the extension portion 52, together with the side sill 20, can withstand the initial collision load.

[0082] Since the extension portion 52 extends continuously in the longitudinal direction of the vehicle, the jack-up attachment 70 is mounted on the lower surface of the extension portion 52. Because the jack-up attachment 70 has a fixing portion 71, the jack-up load is mainly input to the side sill 20 via the fixing portion 71. The frame 5 and the side sill 20 can ensure the necessary rigidity against the jack-up load locally applied to the vehicle 1.

[0083] Frame 5 is made of an extruded aluminum alloy and is suitable for the battery housing 4 in terms of its light weight, corrosion resistance, and heat dissipation. On the other hand, frame 5, made of an extruded aluminum alloy, has lower rigidity than the side sill 20, which is made of steel plate. However, since the fixing part 71 applies the jacking load to the side sill 20, the rigidity required at the jacking point can be ensured by both the side sill 20 and frame 5.

[0084] This structure does not adversely affect the seal 44 between the frame 5 and the cover 42, or the seal 44 between the frame 5 and the base 43. The battery housing 4 can stably maintain the sealed structure of the housing space 40.

[0085] Furthermore, since the extension portion 52 extends continuously in the longitudinal direction of the vehicle from the front end to the rear end of the side sill 20, as shown by the dashed line in Figure 2, the hanger 10 that supports the vehicle 1 during its manufacture supports the vehicle 1 via the extension portion 52 of the frame 5. The load applied from the hanger 10 to the vehicle 1 is distributed rather than localized. Even though the hanger 10 supports the frame 5, the seal 44 between the frame 5 and the cover 42, and the seal 44 between the frame 5 and the base 43 are not adversely affected. The frame 5 is not provided with any notches that would allow the hanger 10 to directly support the side sill 20.

[0086] Furthermore, the frame 5 is not limited to being made of extruded material.

[0087] In the lower structure of the vehicle 1 described above, the fastening portion 6 is located in a position that coincides with the cross-sectional center C of the side sill 20 in the vehicle width direction. The cross-sectional center C here may be the geometric center of the cross-section of the side sill 20, which has a roughly rectangular shape.

[0088] Because the fastening portion 6 is located in a position that coincides with the cross-sectional center C of the side sill 20, a portion of the frame 5 of the battery housing 4, that is, a portion of the extension portion 52, is located at least further outward in the vehicle width direction than the fastening portion 6. In the vehicle width direction, the outer end of the extension portion 52 in the vehicle width direction is located close to the outer wall 202 of the side sill 20. In the example of Figure 2, the outer end of the extension portion 52 in the vehicle width direction is in the same position as the outer wall 202 of the side sill 20.

[0089] Since the outer end of the extension 52 in the vehicle width direction is at the same position as the outer wall 202 of the side sill 20, as described above, when an initial collision load is applied to the side sill 20 during a side collision, an initial collision load is also applied to the frame 5 at the same time, or substantially at the same time.

[0090] Furthermore, after the initial collision load is applied, the side sill 20 and the frame 5 absorb energy in parallel.

[0091] Because the fastening portion 6 is located in a position that coincides with the cross-sectional center C of the side sill 20 in the vehicle width direction, the understructure of the vehicle 1 can shorten the energy absorption stroke in response to load input during a side collision.

[0092] Because the energy absorption stroke by the side sill 20 and frame 5 is short, the battery 41 housing space 40 can be expanded in the vehicle width direction. This expansion of the housing space 40 makes it possible to increase the battery 41 mounting capacity of the vehicle 1.

[0093] Therefore, the understructure of vehicle 1 can increase the mounting capacity of the battery 41 while ensuring energy absorption during side collisions.

[0094] Furthermore, the second flange 212 and the fourth flange 224 of the side sill 20 are positioned between the fastening portion 6 and the main body portion 51 of the frame 5 to avoid interference with the fastening portion 6 and the main body portion 51 of the frame 5.

[0095] Here, Figure 5 shows a modified example regarding the position of the fastening portion 6. As shown in upper Figure 501, the fastening portion 6 may be located outside the cross-sectional center C of the side sill 20 in the vehicle width direction. Also, as shown in lower Figure 502, the collar 61 of the fastening portion 6 may be located in a position that coincides with the cross-sectional center C of the side sill 20.

[0096] In addition to the examples in Figures 2 and 5, there may be various other examples in which the fastening portion 6 is located at a position that coincides with the cross-sectional center C of the side sill 20, or located outside the cross-sectional center C in the vehicle width direction.

[0097] Furthermore, as shown in Figure 2, the inner end of the side sill 20 in the vehicle width direction, i.e., the inner wall 201, is located further out in the vehicle width direction than the inner end of the frame 5 in the vehicle width direction. The narrow width of the side sill 20 improves ease of entry and exit from the vehicle 1.

[0098] Figure 6 shows a modified example of the side sill shape. The inner wall 201 of the side sill 200 is located at the same position as the inner end of the frame 5 in the vehicle width direction. The entire side sill 20 overlaps with the frame 5 in the vehicle width direction. The main body 51 of the frame 5 is located below the inner 21 of the side sill 20.

[0099] In other words, the frame 5 is not located further inward in the vehicle width direction than the side sill 200. Because the frame 5 is located further outward in the vehicle width direction, the battery 41 housing space 40 can be expanded in the vehicle width direction. [Explanation of symbols]

[0100] 1 vehicle 20 Side sill 200 Side Sill 21 Inner 22 Outer 30 Floor Panels 4 Battery housing 41 batteries 5 frames 51 Main body 52 Stretching section 6. Fastening part 61 Colors 62 volts 70 Jack-up attachment 71 Fixed part

Claims

1. A side sill having a closed cross-section is located at the side end of the floor panel in the vehicle width direction and extends in the vehicle longitudinal direction, A battery housing located beneath the floor panel and containing a battery housed in a storage space, The battery housing is fastened to the lower part of the side sill, The fastening portion is located in the vehicle width direction at a position that coincides with the center of the cross-section of the side sill, or at a position that is outside the center of the cross-section in the vehicle width direction. The undercarriage of the vehicle.

2. In the vehicle substructure described in claim 1, The battery housing has a frame located on the outer edge of the battery housing in the vehicle width direction and extending in the vehicle longitudinal direction, and forming the housing space on the inside in the vehicle width direction. The fastening portion fastens the frame to the lower part of the side sill. The undercarriage of the vehicle.

3. In the vehicle substructure described in claim 2, The inner end of the side sill in the vehicle width direction is located at the same position as the inner end of the frame in the vehicle width direction, or is located further out in the vehicle width direction than the inner end of the frame. The undercarriage of the vehicle.

4. In the vehicle substructure described in claim 2, The outer end of the frame in the vehicle width direction is at approximately the same position as the outer end of the side sill in the vehicle width direction, The undercarriage of the vehicle.

5. In the vehicle substructure described in claim 2, The frame further comprises a jack-up attachment mounted on the lower surface of the frame. The undercarriage of the vehicle.

6. In the vehicle substructure described in claim 5, The jack-up attachment has a fixing portion that penetrates the frame vertically and is fixed to the lower part of the side sill. The undercarriage of the vehicle.

7. In the vehicle substructure according to claim 5 or 6, The frame is made of an extruded aluminum alloy. The undercarriage of the vehicle.

8. In the vehicle substructure described in claim 2, The side sill has an inner and an outer that are joined in the vehicle width direction, The fastening portion is fastened to the outer, The undercarriage of the vehicle.

9. In the vehicle substructure described in claim 2, The fastening portion includes a collar interposed between the lower part of the side sill and the frame, and a bolt inserted into the collar and fastening the frame and the side sill. The undercarriage of the vehicle.

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