Vehicle undercarriage

Abstract

To appropriately distribute and absorb the load applied to the vehicle during a side collision. [Solution] The battery pack comprises a battery pack 10, cross members 4L, 4R positioned above the battery pack, a battery side frame 6 supporting the outer side of the battery pack in the vehicle width direction, and side sills 2L, 2R positioned further outward in the vehicle width direction than the cross members and battery side frame. The thickness of the outer portion in the vehicle width direction of the cross member, which has a closed or open cross section shape, is smaller than the thickness of the inner portion in the vehicle width direction, and the thickness of the outer portion in the vehicle width direction of the battery side frame, which has a closed or open cross section shape, is smaller than the thickness of the inner portion in the vehicle width direction.

Description

Technical Field

[0001] The present invention relates to a vehicle underbody structure.

Background Art

[0002] In recent years, efforts have been actively made to provide access to a sustainable transportation system that takes into account people in vulnerable positions such as the elderly, disabled, and children among traffic participants. Research and development have been conducted to further improve traffic safety and convenience through development related to collision safety performance. For example, Patent Documents 1 to 3 propose vehicle body structures for enhancing safety performance against side collisions.

[0003] The vehicle underbody structure described in Patent Document 1 includes rockers respectively disposed on both outer sides in the vehicle width direction. The rocker includes an outer part and an inner part that form a closed cross-section, and a shock absorption part provided between the outer part and the inner part. The outer part, the inner part, and the shock absorption part are integrally formed by extrusion or the like. This vehicle underbody structure absorbs the load input to the rocker by a side collision by plastically deforming the shock absorption part.

[0004] The vehicle body understructure described in Patent Document 2 includes a side frame that connects a battery pack and a side sill disposed outside the battery pack in the vehicle width direction. This vehicle body understructure absorbs the load input to the side sill by a side collision by plastically deforming the side frame.

[0005] The floor structure of the vehicle body described in Patent Document 3 absorbs the load input to the side sill by a side collision by folding a plurality of locations in the vehicle width direction of cross members extending inward in the vehicle width direction from the side sill.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

[0007] One of the objectives of the present invention is to appropriately distribute and absorb the load applied to a vehicle in the event of a side collision. [Means for solving the problem]

[0008] A vehicle understructure according to one aspect of the present invention is: A battery pack having a battery and a case for housing the battery, A cross member positioned above the aforementioned battery pack and extending in the vehicle width direction, A battery side frame is positioned further outward in the vehicle width direction than the battery pack and supports the side of the battery pack, A side sill is positioned further outward in the vehicle width direction than the cross member and the battery side frame, and extends in the vehicle longitudinal direction. Equipped with, When viewed in the vehicle width direction, at least a portion of the cross member overlaps with the side sill, and at least a portion of the battery side frame overlaps with the side sill. The cross member has a closed or open cross-sectional shape in a cross section perpendicular to the vehicle width direction. The thickness of the outer portion of the cross member in the vehicle width direction is smaller than the thickness of the inner portion of the cross member in the vehicle width direction. The battery side frame has a closed or open cross-sectional shape in a cross-section perpendicular to the vehicle's front-rear direction. The thickness of the outer portion of the battery side frame in the vehicle width direction is smaller than the thickness of the inner portion of the battery side frame in the vehicle width direction.

[0009] Another embodiment of the present invention is a vehicle understructure, A battery pack having a battery and a case for housing the battery, A cross member positioned above the aforementioned battery pack and extending in the vehicle width direction, A battery side frame is positioned outward in the vehicle width direction from the aforementioned battery pack and supports the side of the battery pack, A side sill is positioned further outward in the vehicle width direction than the cross member and the battery side frame, and extends in the vehicle longitudinal direction. Equipped with, When viewed in the vehicle width direction, at least a portion of the cross member overlaps with the side sill, and at least a portion of the battery side frame overlaps with the side sill. The cross member has a closed or open cross-sectional shape in a cross section perpendicular to the vehicle width direction. The thickness of the outer portion of the cross member in the vehicle width direction is smaller than the thickness of the inner portion of the cross member in the vehicle width direction. The battery side frame has a closed or open cross-sectional shape in a cross-section perpendicular to the vehicle's front-rear direction. The thickness of the outer portion of the battery side frame in the vehicle width direction is smaller than the thickness of the inner portion of the battery side frame in the vehicle width direction. The side sill has a closed or open cross-sectional shape in a cross section perpendicular to the vehicle's longitudinal direction, including a plurality of transverse plates extending in the vehicle's width direction. The thickness of some of the aforementioned horizontal boards differs from the thickness of the other horizontal boards. [Effects of the Invention]

[0010] According to the present invention, the load applied to a vehicle by a side collision can be appropriately distributed and absorbed. [Brief explanation of the drawing]

[0011] [Figure 1]A perspective view of an example of a vehicle lower structure for explaining an embodiment of the present invention. [Figure 2] A sectional view taken along line II-II of FIG. 1. [Figure 3] A sectional view taken along line III-III of FIG. 1. [Figure 4] A sectional view of an example of a vehicle lower structure for explaining an embodiment of the present invention. [Figure 5] A sectional view of a modified example of the vehicle lower structure of FIG. 4. [Figure 6] A sectional view of another modified example of the vehicle lower structure of FIG. 4. [Figure 7] A sectional view of another modified example of the vehicle lower structure of FIG. 4. [Figure 8] A sectional view of another modified example of the vehicle lower structure of FIG. 4.

Mode for Carrying Out the Invention

[0012] An example of a vehicle lower structure for explaining an embodiment of the present invention will be described based on the accompanying drawings. The drawings are to be viewed in the direction of the reference numerals. In this specification and the like, for the sake of simplicity and clarity of explanation, the front, rear, left, and right directions are described according to the direction seen from the driver of the vehicle, and in the drawings, the front of the vehicle is indicated as Fr, the rear as Rr, the left as L, the right as R, the upper as U, and the lower as D.

[0013] The vehicle lower structure shown in FIGS. 1 to 3 is, for example, a lower structure of an electric vehicle such as a battery electric vehicle, a hybrid vehicle (including a plug-in hybrid vehicle), or a fuel cell vehicle. This vehicle lower structure includes a vehicle body 1 and a battery pack 10. The vehicle body 1 constitutes the skeleton of the vehicle, and the battery pack 10 stores and discharges electric power to be supplied to a motor or the like that is a driving source of the vehicle.

[0014] The vehicle body 1 includes side sills 2L, 2R, a center tunnel 3, and cross members 4L, 4R. The side sills 2L, 2R, the center tunnel 3, and the cross members 4L, 4R constitute part of the vehicle's frame. Although not shown in the illustration, the vehicle body 1 may also include a floor panel and other cross members positioned in front of or behind the cross members 4L, 4R.

[0015] The side sills 2L and 2R are spaced apart in the vehicle width direction (left-right direction) and extend in the vehicle longitudinal direction. The center tunnel 3 is located between the side sills 2L and 2R and extends in the vehicle longitudinal direction. The cross member 4L is located between the side sill 2L and the center tunnel 3, and the cross member 4R is located between the center tunnel 3 and the side sill 2R, both extending in the vehicle width direction. The ends of the cross member 4L are joined to the side sills 2L and the center tunnel 3 by appropriate methods such as welding, fastening with bolts or rivets. The ends of the cross member 4R are also joined to the center tunnel 3 and the side sills 2R by appropriate methods such as welding or fastening.

[0016] The cross members 4L and 4R are aligned on the same line extending in the vehicle width direction, connected via the center tunnel 3, and spanned as a single unit between the side sills 2L and 2R. The center tunnel 3 is provided to increase the rigidity of the vehicle body 1 and / or to accommodate the wire harness extending from the battery pack 10. However, the center tunnel 3 may be omitted. When the center tunnel 3 is omitted, the cross members 4L and 4R are constructed from a single member and spanned between the side sills 2L and 2R.

[0017] The battery pack 10 is positioned between the side sills 2L and 2R in the vehicle width direction and below the cross members 4L and 4R. As shown in Figures 2 and 3, the battery pack 10 comprises a battery 11 and a case 12 that houses the battery 11.

[0018] The battery 11 includes multiple battery cells. These battery cells are, for example, lithium-ion batteries or nickel-metal hydride batteries using a liquid electrolyte, or all-solid-state batteries using a solid electrolyte. Typically, the battery 11 is modularized with multiple battery cells connected in series and / or parallel. In the example shown in Figure 2, two modularized batteries 11 are arranged side-by-side in the front-to-back direction, but the number and arrangement of the batteries 11 are not particularly limited.

[0019] Case 12 includes a case body 13 and a case cover 14. The case body 13 is formed in a tray shape capable of housing the battery 11. The case body 13 is made of a metal plate material such as aluminum alloy or steel. The case cover 14 covers the case body 13 from above. Case 12 also houses electrical equipment 15 such as a junction box and busbars. The junction box controls the connection between the battery pack 10 and the inverter that drives the charging system and motor mounted on the vehicle. The busbars connect the modularized batteries 11 to each other and between the batteries 11 and the junction box.

[0020] The battery pack 10 is fixed to the vehicle body 1 via a base plate 5 and a battery frame 6. The battery pack 10 is placed on the base plate 5, and the case body 13 of the battery pack 10 is fixed to the base plate 5. The edges of the base plate 5 extend outward beyond the battery pack 10 in the vehicle's longitudinal and vehicle width directions. The battery frame 6 is provided to surround the battery pack 10 and is joined to the edges of the base plate 5 by appropriate methods such as welding and fastening. The battery frame 6 is then fixed to the vehicle body 1. The fixing points of the battery frame 6 on the vehicle body 1 are set as appropriate, but examples include the side sills 2L, 2R, other cross members located in front of and behind the cross members 4L, 4R, and the floor panel. The case body 13 may be fixed to the battery frame 6 in addition to the base plate 5, or instead of the base plate 5.

[0021] Figure 3 shows the structure around side sill 2L. The structure around side sill 2R is configured similarly. The battery frame 6 includes a battery side frame 7 that supports the side of the battery pack 10 near side sill 2L. The battery side frame 7 extends in the longitudinal direction of the vehicle between the battery pack 10 and side sill 2L.

[0022] When viewed in the vehicle width direction, the cross member 4L and the side sill 2L overlap, and the battery side frame 7 and the side sill 2L overlap. When a load is applied to the side sill 2L from the outside in the vehicle width direction, the applied load is distributed and transmitted to the cross member 4L and the battery side frame 7. In terms of transmitting the load to the cross member 4L and the battery side frame 7, when viewed in the vehicle width direction, it is sufficient that at least a part of the cross member 4L overlaps with the side sill 2L, and at least a part of the battery side frame 7 overlaps with the side sill 2L.

[0023] The load transmitted to the cross member 4L is borne by the center tunnel 3, and further borne by the side sill 2R via the cross member 4R. In addition, the load transmitted to the battery side frame 7 is borne by the battery pack 10. This generates a reaction force on the side sill 2L, suppressing excessive inward intrusion of the side sill 2L in the vehicle width direction.

[0024] Here, the side sill 2L, cross member 4L, and battery side frame 7 have a closed or open cross-sectional shape in a cross section perpendicular to the extending direction. That is, the side sill 2L, cross member 4L, and battery side frame 7 are components composed of a combination of horizontal and vertical plates, and are, for example, extruded aluminum alloy. The thickness of the outer portion 40 and inner portion 41 of the cross member 4L in the vehicle width direction, and the thickness of the outer portion 70 and inner portion 71 of the battery side frame 7 in the vehicle width direction, refer to the thickness of the horizontal and / or vertical plates that constitute each part. The thickness of the outer portion 40 of the cross member 4L in the vehicle width direction is smaller than the thickness of the inner portion 41, and the thickness of the outer portion 70 of the battery side frame 7 is smaller than the thickness of the inner portion 71.

[0025] In the example shown in Figure 3, the thickness T1 of the transverse plate 42 of the outer portion 40 in the vehicle width direction of the cross member 4L is smaller than the thickness T2 of the transverse plate 43 of the inner portion 41. The thickness T3 of the transverse plate 72 of the outer portion 70 in the vehicle width direction of the battery side frame 7 is smaller than the thickness T4 of the transverse plate 73 of the inner portion 71. In the cross member 4L, the outer portion 40, which is relatively thinner, functions as an impact absorber. The outer portion 40 undergoes plastic deformation due to the load transmitted to the cross member 4L, and a portion of the load is absorbed. Similarly, in the battery side frame 7, the outer portion 70, which is relatively thinner, functions as an impact absorber. The outer portion 70 undergoes plastic deformation due to the load transmitted to the battery side frame 7, and a portion of the load is absorbed.

[0026] In this way, by distributing the load applied to the side sill 2L to the cross member 4L and the battery side frame 7, the strength requirements for the cross member 4L and the battery side frame 7, as well as for the center tunnel 3, side sill 2R, and battery pack 10 that bear the load transmitted to the cross member 4L and the battery side frame 7, can be relaxed. Furthermore, by absorbing the load distributed to the cross member 4L and the battery side frame 7 with the shock-absorbing parts provided on the cross member 4L and the battery side frame 7 (the outer part 40 of the cross member 4L and the outer part 70 of the battery side frame 7), it is possible to achieve sufficient shock absorption overall while suppressing the amount of deformation of each shock-absorbing part.

[0027] Preferably, the battery side frame 7 is joined to the side sill 2L. This maintains the load transmission path from the side sill 2L to the battery side frame 7 regardless of the deformation of the battery side frame 7 when a load is applied, and ensures that the load is reliably transmitted from the side sill 2L to the battery side frame 7. In the example shown in Figure 3, the battery side frame 7 has a projection 74 that protrudes outward in the vehicle width direction from the outer portion 70, and one side sill 2L is provided with a recess 20 that accommodates the projection 74. The projection 74 housed in the recess 20 is fastened to the recess 20 in the vertical direction by bolts B. In this way, by providing a projection 74 that protrudes outward in the vehicle width direction and a recess 20 that accommodates the projection 74, and joining the two in the vertical direction intersecting the vehicle width direction, the strength of the joint can be ensured.

[0028] Preferably, the battery pack 10 is fixed to the battery side frame 7, and more preferably to the relatively strong inner portion 71 of the battery side frame 7. This maintains the load transmission path from the battery side frame 7 to the battery pack 10 regardless of the deformation of the battery side frame 7 when a load is applied, and ensures that the battery pack 10 reliably bears the load. In the example shown in Figure 3, the case body 13 of the battery pack 10 has a flange 16 that extends outward in the vehicle width direction, and the flange 16 is superimposed on the upper surface of the inner portion 71 of the battery side frame 7 and fastened to the inner portion 71 by bolts B.

[0029] Preferably, the boundary between the outer portion 40 and the inner portion 41 of the cross member 4L and the boundary between the outer portion 70 and the inner portion 71 of the battery side frame 7 are located at the same position in the vehicle width direction. This allows both the outer portion 40 of the cross member 4L and the outer portion 70 of the battery side frame 7, which function as impact absorbers, to deform sufficiently, thereby achieving effective impact absorption.

[0030] Furthermore, from the viewpoint of shock absorption, as shown in Figure 3, a gap G1 may be provided between the end face of the outer portion 40 of the cross member 4L and the side surface of the side sill 2L facing the end face in the vehicle width direction, and a gap G2 may be provided between the end face of the outer portion 70 (including the protruding portion 74) of the battery side frame 7 and the side surface of the side sill 2L facing the end face in the vehicle width direction. These gaps G1 and G2 allow the side sill 2L to be displaced inward in the vehicle width direction when a load is applied to the side sill 2L from the outside in the vehicle width direction. This allows for further shock absorption by utilizing the deflection of the side sill 2L.

[0031] The gap G1 between the cross member 4L and the side sill 2L, and the gap G2 between the battery side frame 7 and the side sill 2L, may be the same or different. By making the gaps G1 and G2 different, the timing at which the end face of the outer portion 40 of the cross member 4L and the side surface of the side sill 2L come into contact, and the timing at which the end face of the outer portion 70 of the battery side frame 7 and the side surface of the side sill 2L come into contact can be made different, thereby controlling the load distribution ratio on the cross member 4L and the battery side frame 7.

[0032] The vehicle understructure shown in Figure 4 utilizes the side sill 2L for impact absorption, while the modified versions shown in Figures 5 to 8 utilize the side sill 2L not only for impact absorption but also for controlling the load distribution ratio to the cross member 4L and battery side frame 7. In the vehicle understructures shown in Figures 4 to 8, elements common to the vehicle understructures shown in Figures 1 to 3 are denoted by the same reference numerals, and their explanations are omitted.

[0033] As described above, the side sill 2L is a component composed of a combination of horizontal and vertical plates, and has a closed or open cross-sectional shape in a cross-section perpendicular to the extending direction. The thickness of all horizontal plates located in the outer portion 21 of the side sill 2L is the same, with a thickness of T5. The thickness of all horizontal plates in the inner portion 22 of the side sill 2L in the vehicle width direction is the same, with a thickness of T6 which is smaller than the thickness T5 of the horizontal plates in the outer portion 21. The inner portion 22 of the side sill 2L, where the horizontal plate thickness is relatively small, functions as an impact absorber. The inner portion 22 undergoes plastic deformation due to the load applied to the side sill 2L, and a portion of the load is absorbed.

[0034] By making the thickness of all the lateral plates located on the outer portion 21 of the side sill 2L the same, the load applied to the outer portion 21 from the outside in the vehicle width direction can be transmitted to the inner portion 22 without bias. On the other hand, the thickness of the lateral plates located on the inner portion 22 may be different. By making the thickness of the lateral plates located on the inner portion 22 different, the load distribution ratio to the cross member 4L and the battery side frame 7 can be controlled.

[0035] In the example shown in Figure 5, the thickness T6-1 of the horizontal plate 26 located at the upper part 23 of the inner portion 22 of the side sill 2L, which overlaps with at least a part of the cross member 4L, is smaller than the thickness T6-2 of the horizontal plate 27 located at the lower part 24, which overlaps with at least a part of the battery side frame 7. In this case, the load transfer ratio from the upper part 23, where the horizontal plate is relatively thinner, to the cross member 4L becomes smaller, and the load transfer ratio from the lower part 24, where the horizontal plate is relatively thicker, to the battery side frame 7 becomes larger.

[0036] On the other hand, in the example shown in Figure 6, the thickness T6-2 of the horizontal plate 27 located at the lower part 24 of the inner portion 22 of the side sill 2L, which overlaps with at least a part of the battery side frame 7, is smaller than the thickness T6-1 of the horizontal plate 26 located at the upper part 23, which overlaps with at least a part of the cross member 4L. In this case, the load transfer ratio from the lower part 24, where the horizontal plate is relatively thinner, to the battery side frame 7 becomes smaller, and the load transfer ratio from the upper part 23, where the horizontal plate is relatively thicker, to the cross member 4L becomes larger.

[0037] Furthermore, as shown in Figures 5 and 6, the horizontal plate of the inner portion 22 of the side sill 2L may be omitted and made hollow in the intermediate portion 25 between the upper part 23 of the side sill 2L that overlaps with the cross member 4L and the lower part 24 of the side sill 2L that overlaps with the battery side frame 7. This allows the load to be guided to the upper part 23 and the lower part 24, and the load to be effectively transmitted to the cross member 4L and the battery side frame 7.

[0038] Furthermore, the thickness of the multiple vertical boards that span between the multiple horizontal boards in the side sill 2L may be varied.

[0039] In the example shown in Figure 7, the thickness T7-1 of the vertical plate 28 located at the upper part 23 of the side sill 2L, which overlaps with at least a portion of the cross member 4L, is smaller than the thickness T7-2 of the vertical plate 29 located at the lower part 24 of the side sill 2L, which overlaps with at least a portion of the battery side frame 7. In this case, the load transfer ratio from the upper part 23, where the vertical plate is relatively thinner, to the cross member 4L becomes smaller, and the load transfer ratio from the lower part 24, where the vertical plate is relatively thicker, to the battery side frame 7 becomes larger.

[0040] On the other hand, in the example shown in Figure 8, the thickness T7-2 of the vertical plate 29 located at the lower part 24 of the side sill 2L is smaller than the thickness T7-1 of the vertical plate 28 located at the upper part 23 of the side sill 2L. In this case, the load transfer ratio from the lower part 24, where the vertical plate is relatively thinner, to the battery side frame 7 becomes smaller, and the load transfer ratio from the upper part 23, where the vertical plate is relatively thicker, to the cross member 4L becomes larger.

[0041] Although embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and modifications, improvements, etc., can be made as appropriate. This specification includes at least the following matters. Note that the components etc. in parentheses indicate those corresponding to the above embodiments, but the invention is not limited thereto. (1) A battery pack (battery pack 10) having a battery (battery 11) and a case (case 12) that houses the battery, A cross member (cross member 4L, 4R) is positioned above the aforementioned battery pack and extends in the vehicle width direction, A battery side frame (battery side frame 7) is positioned outward in the vehicle width direction from the aforementioned battery pack and supports the side of the battery pack, The side sills (side sills 2L, 2R) are positioned outward in the vehicle width direction from the cross member and the battery side frame, and extend in the vehicle longitudinal direction. Equipped with, When viewed in the vehicle width direction, at least a portion of the cross member overlaps with the side sill, and at least a portion of the battery side frame overlaps with the side sill. The cross member has a closed or open cross-sectional shape in a cross section perpendicular to the vehicle width direction. The thickness (thickness T1) of the outer portion (outer portion 40) of the cross member in the vehicle width direction is smaller than the thickness (thickness T2) of the inner portion (inner portion 41) of the cross member in the vehicle width direction. The battery side frame has a closed or open cross-sectional shape in a cross-section perpendicular to the vehicle's front-rear direction. The thickness (thickness T3) of the outer portion (outer portion 70) of the battery side frame in the vehicle width direction is smaller than the thickness (thickness T4) of the inner portion (inner portion 71) of the battery side frame in the vehicle width direction. Vehicle understructure.

[0042] According to the vehicle understructure described in (1) above, the load applied to the side sill can be distributed to the cross member and the battery side frame. A portion of the load transmitted to the cross member is absorbed by the plastic deformation of the outer portion in the vehicle width direction, which has a relatively small thickness, and a portion of the load transmitted to the battery side frame is absorbed by the plastic deformation of the outer portion in the vehicle width direction, which has a relatively small thickness, thereby achieving sufficient shock absorption overall while suppressing the amount of deformation of each part.

[0043] (2) The vehicle understructure of (1) above, When a load is applied to the side sill from the outside in the vehicle width direction, the load is transmitted from the side sill to the cross member and the battery side frame. The load transmitted to the battery side frame is transmitted to the battery pack. Vehicle understructure.

[0044] (3) The vehicle understructure of (1) above, The cross member and the battery side frame are arranged in the vehicle width direction with a gap (gap G1, G2) between them and the side sill. Vehicle understructure.

[0045] According to the vehicle understructure described in (3) above, when a load is applied to the side sill from the outside in the vehicle width direction, the side sill is allowed to be displaced inward in the vehicle width direction, and the deflection of the side sill can be used to further absorb the impact.

[0046] (4) The vehicle understructure of (1) above, The battery pack is fixed to the inner portion of the battery side frame in the vehicle width direction. Vehicle understructure.

[0047] According to the vehicle understructure described in (4) above, regardless of the deformation of the battery side frame when a load is applied, the load transmission path from the battery side frame to the battery pack is maintained, and the load can be reliably borne by the battery pack.

[0048] (5) The vehicle understructure described in (4) above, The boundary between the outer portion and the inner portion in the vehicle width direction of the cross member and the boundary between the outer portion and the inner portion in the vehicle width direction of the battery side frame are at the same position in the vehicle width direction. Vehicle understructure.

[0049] According to the vehicle understructure described in (5) above, both the outer portion of the cross member, which functions as an impact absorber, and the outer portion of the battery side frame can be sufficiently deformed to achieve effective impact absorption.

[0050] (6) The vehicle understructure of (1) above, The outer portion of the battery side frame in the vehicle width direction has a protruding portion (protruding portion 74) that protrudes in the vehicle width direction, The side sill has a recess (recess 20) that accommodates the protruding portion of the battery side frame, The aforementioned protruding portion is fastened to the aforementioned recess in a direction intersecting the vehicle width direction. Vehicle understructure.

[0051] According to the vehicle understructure described in (6) above, regardless of the deformation of the battery side frame when a load is applied, the load transmission path from the side sill to the battery side frame is maintained, and the load can be reliably transmitted from the side sill to the battery side frame. Furthermore, by joining the protruding portion that projects outward in the vehicle width direction and the recess that accommodates the protruding portion in the vertical direction intersecting the vehicle width direction, the strength of the joint can be ensured.

[0052] (7) A battery pack (battery pack 10) having a battery (battery 11) and a case (case 12) that houses the battery, A cross member (cross member 4L, 4R) is positioned above the aforementioned battery pack and extends in the vehicle width direction, A battery side frame (battery side frame 7) is positioned outward in the vehicle width direction from the aforementioned battery pack and supports the aforementioned battery pack, The side sills (side sills 2L, 2R) are positioned outward in the vehicle width direction from the cross member and the battery side frame, and extend in the vehicle longitudinal direction. Equipped with, When viewed in the vehicle width direction, at least a portion of the cross member overlaps with the side sill, and at least a portion of the battery side frame overlaps with the side sill. The cross member has a closed or open cross-sectional shape in a cross section perpendicular to the vehicle width direction. The thickness (thickness T1) of the outer portion (outer portion 40) of the cross member in the vehicle width direction is smaller than the thickness (thickness T2) of the inner portion (inner portion 41) of the cross member in the vehicle width direction. The battery side frame has a closed or open cross-sectional shape in a cross-section perpendicular to the vehicle's front-rear direction. The thickness (thickness T3) of the outer portion (outer portion 70) of the battery side frame in the vehicle width direction is smaller than the thickness (thickness T4) of the inner portion (inner portion 71) of the battery side frame in the vehicle width direction. The side sill has a closed or open cross-sectional shape in a cross section perpendicular to the vehicle's longitudinal direction, including a plurality of transverse plates extending in the vehicle's width direction. The thickness of some of the aforementioned horizontal boards differs from the thickness of the other horizontal boards. Vehicle understructure.

[0053] According to the vehicle understructure described in (7) above, the load applied to the side sill can be distributed to the cross member and the battery side frame. A portion of the load transmitted to the cross member is absorbed by the plastic deformation of the outer portion in the vehicle width direction, which has a relatively small thickness, and a portion of the load transmitted to the battery side frame is absorbed by the plastic deformation of the outer portion in the vehicle width direction, which has a relatively small thickness, in the battery side frame. As a result, sufficient impact absorption can be achieved overall while suppressing the amount of deformation in each part. Furthermore, load absorption can be promoted by the plastic deformation of the portion of the cross member where the lateral plate is relatively thin.

[0054] (8) The vehicle understructure as described in (7) above, Of the aforementioned multiple horizontal plates, the thickness (thickness T5) of the outer horizontal plate located in the outer portion (outer portion 21) of the side sill in the vehicle width direction is equal. Vehicle understructure.

[0055] According to the vehicle understructure described in (8) above, the load applied to the outer part of the side sill in the vehicle width direction from the outside in the vehicle width direction can be transmitted to the inner part without bias.

[0056] (9) The vehicle understructure described in (8) above, Of the plurality of horizontal plates, the thickness (thickness T6) of the inner horizontal plate located in the inner portion (inner portion 22) of the side sill in the vehicle width direction is smaller than the thickness (thickness T5) of the outer horizontal plate. Vehicle understructure.

[0057] According to the vehicle understructure described in (9) above, the inner portion of the side sill, where the thickness of the lateral plate is relatively small, can function as an impact absorber, thereby absorbing a portion of the load.

[0058] (10) The vehicle understructure described in (8) above, Of the inner horizontal plates located in the inner portion of the side sill in the vehicle width direction, the thickness (thickness T6-1) of the inner horizontal plate (horizontal plate 26) located in the upper part (upper part 23) of the side sill that overlaps with at least a part of the cross member is different from the thickness (thickness T6-2) of the inner horizontal plate (horizontal plate 27) located in the lower part (lower part 24) of the side sill that overlaps with at least a part of the battery side frame. Vehicle understructure.

[0059] According to the vehicle understructure described in (10) above, the load distribution ratio to the cross member and battery side frame can be controlled.

[0060] (11) The vehicle understructure described in (8) above, In the intermediate portion (intermediate portion 25) of the side sill, between the upper part of the side sill which overlaps with at least a portion of the cross member and the lower part of the side sill which overlaps with at least a portion of the battery side frame, the inner portion in the vehicle width direction is hollow. Vehicle understructure.

[0061] According to the vehicle understructure described in (11) above, load can be directed to the upper and lower parts of the side sill, effectively transferring the load to the cross member and battery side frame.

[0062] (12) The vehicle understructure described in (7) above, The side sill has a plurality of vertical boards that are spanned between the plurality of horizontal boards, The thickness (thickness T7-1) of the upper vertical plate (vertical plate 28) located on the upper part of the side sill that overlaps with at least a portion of the cross member, and the thickness (thickness T7-2) of the lower vertical plate (vertical plate 29) located on the lower part of the side sill that overlaps with at least a portion of the battery side frame, are different. Vehicle understructure.

[0063] According to the vehicle understructure described in (12) above, the load distribution ratio to the cross member and battery side frame can be controlled. [Explanation of Symbols]

[0064] 1. Vehicle body 2L, 2R side sill 3 Center Tunnel 4L, 4R Crossmember 5 Base plate 6 Battery Frame 7 Battery side frame 10 Battery Packs 11 batteries 12 cases 13 Case body 14 Case Cover 15 Electrical equipment 16 flange 20 recesses 21 Outer part 22 Inner part 23 Top 24 Lower 25 Middle section 26,27 horizontal board 28,29 Vertical boards 40 outer part 41 Inner part 42,43 Horizontal board 70 outer part 71 Inner part 72,73 Horizontal board 74 Protrusion B bolt G1 Gap G2 Gap

Claims

1. A battery pack having a battery and a case for housing the battery, A cross member positioned above the aforementioned battery pack and extending in the vehicle width direction, A battery side frame is positioned further outward in the vehicle width direction than the battery pack and supports the side of the battery pack, A side sill is positioned further outward in the vehicle width direction than the cross member and the battery side frame, and extends in the vehicle longitudinal direction. Equipped with, When viewed in the vehicle width direction, at least a portion of the cross member overlaps with the side sill, and at least a portion of the battery side frame overlaps with the side sill. The cross member has a closed or open cross-sectional shape in a cross section perpendicular to the vehicle width direction. The thickness of the outer portion of the cross member in the vehicle width direction is smaller than the thickness of the inner portion of the cross member in the vehicle width direction. The battery side frame has a closed or open cross-sectional shape in a cross-section perpendicular to the vehicle's front-rear direction. The thickness of the outer portion of the battery side frame in the vehicle width direction is smaller than the thickness of the inner portion of the battery side frame in the vehicle width direction. Vehicle understructure.

2. The vehicle understructure according to claim 1, When a load is applied to the side sill from the outside in the vehicle width direction, the load is transmitted from the side sill to the cross member and the battery side frame. The load transmitted to the battery side frame is transmitted to the battery pack. Vehicle understructure.

3. The vehicle understructure according to claim 1, The cross member and the battery side frame are arranged in the vehicle width direction with a gap between them and the side sill. Vehicle understructure.

4. The vehicle understructure according to claim 1, The battery pack is fixed to the inner portion of the battery side frame in the vehicle width direction. Vehicle understructure.

5. The vehicle understructure according to claim 4, The boundary between the outer portion and the inner portion in the vehicle width direction of the cross member and the boundary between the outer portion and the inner portion in the vehicle width direction of the battery side frame are at the same position in the vehicle width direction. Vehicle understructure.

6. The vehicle understructure according to claim 1, The outer portion of the battery side frame in the vehicle width direction has a protruding portion that projects outward in the vehicle width direction, The side sill has a recess that accommodates the protruding portion of the battery side frame, The aforementioned protruding portion is fastened to the recess in a direction intersecting the vehicle width direction. Vehicle understructure.

7. A battery pack having a battery and a case for housing the battery, A cross member positioned above the aforementioned battery pack and extending in the vehicle width direction, A battery side frame is positioned outward in the vehicle width direction from the aforementioned battery pack and supports the side of the battery pack, A side sill is positioned further outward in the vehicle width direction than the cross member and the battery side frame, and extends in the vehicle longitudinal direction. Equipped with, When viewed in the vehicle width direction, at least a portion of the cross member overlaps with the side sill, and at least a portion of the battery side frame overlaps with the side sill. The cross member has a closed or open cross-sectional shape in a cross section perpendicular to the vehicle width direction. The thickness of the outer portion of the cross member in the vehicle width direction is smaller than the thickness of the inner portion of the cross member in the vehicle width direction. The battery side frame has a closed or open cross-sectional shape in a cross-section perpendicular to the vehicle's front-rear direction. The thickness of the outer portion of the battery side frame in the vehicle width direction is smaller than the thickness of the inner portion of the battery side frame in the vehicle width direction. The side sill has a closed or open cross-sectional shape in a cross section perpendicular to the vehicle's longitudinal direction, including a plurality of transverse plates extending in the vehicle's width direction. The thickness of some of the aforementioned horizontal boards differs from the thickness of the other horizontal boards. Vehicle understructure.

8. The vehicle understructure according to claim 7, Of the aforementioned plurality of horizontal plates, the thickness of the outer horizontal plate located on the outer portion of the side sill in the vehicle width direction is equal. Vehicle understructure.

9. The vehicle understructure according to claim 8, Of the plurality of horizontal plates, the thickness of the inner horizontal plate located in the inner portion of the side sill in the vehicle width direction is smaller than the thickness of the outer horizontal plate. Vehicle understructure.

10. The vehicle understructure according to claim 8, Of the inner transverse plates located in the inner portion of the side sill in the vehicle width direction, the thickness of the inner transverse plate located in the upper part of the side sill that overlaps with at least a portion of the cross member is different from the thickness of the inner transverse plate located in the lower part of the side sill that overlaps with at least a portion of the battery side frame. Vehicle understructure.

11. The vehicle understructure according to claim 8, In the intermediate portion of the side sill between the upper part of the side sill which overlaps with at least a portion of the cross member and the lower part of the side sill which overlaps with at least a portion of the battery side frame, the inner portion in the vehicle width direction is hollow. Vehicle understructure.

12. The vehicle understructure according to claim 7, The side sill has a plurality of vertical boards that are spanned between the plurality of horizontal boards, The thickness of the upper vertical plate located above the side sill, which overlaps with at least a portion of the cross member, is different from the thickness of the lower vertical plate located below the side sill, which overlaps with at least a portion of the battery side frame. Vehicle understructure.

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