Vehicle lower part structure

Abstract

To provide a vehicle lower part structure in which a transmission path of a collision load is secured upon a front collision or rear collision of a vehicle.SOLUTION: Inclined ribs 50, 52, 54, and 56 are provided on a bottom wall 34 of a battery case 32. The inclined ribs 50 and 52 transmit a collision load input from a vehicle front side to sides of rockers 16 and 18, and the inclined ribs 54 and 56 transmit a collision load input from a vehicle rear side to the sides of the rockers 16 and 18. In other words, the inclined ribs 50, 52, 54, and 56 are provided on the bottom wall 34 of the battery case 32, and thereby, a transmission path of the collision load (so-called front collision load or so-called rear collision load) input from the vehicle front side or the vehicle rear side can be secured.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] In the electric vehicle described in Patent Document 1 below, a substantially rectangular parallelepiped battery storage space is formed by a space defined by a pair of left and right sill beams (sometimes called rockers), a front cross member, a rear cross member, and a cooling plate, and multiple batteries (battery packs) are stored in this battery storage space. In this prior art, the vehicle floor is formed by a cover plate that covers the top surface of the battery pack. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Publication number CN114940214 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the above prior art, for example, when a frontal collision load (collision load) occurs in a battery pack composed of multiple batteries during a frontal collision of a vehicle (hereinafter referred to as a "vehicle frontal collision"), there are concerns about the transmission path of the collision load.

[0005] SUMMARY OF THE PRESENT INVETION The present invention has been made in consideration of the above circumstances, and has an object to provide a vehicle underbody structure that ensures a transmission path for a collision load in the event of a frontal or rear collision of the vehicle. [Means for solving the problem]

[0006] The vehicle undercarriage structure of the invention described in claim 1 comprises a battery pack including a storage section in which battery cells are housed and a cover that covers the storage section and forms a floor of the vehicle compartment, and a first rib provided on a bottom wall of the battery pack and transmits a collision load input from the front or rear of the vehicle to a rocker side that forms part of the vehicle frame and extends in the fore-and-aft direction of the vehicle outside the battery pack in the vehicle width direction.

[0007] The vehicle underbody structure according to the invention recited in claim 1 includes a battery pack and a first rib. The battery pack includes a storage section and a cover, and the storage section stores battery cells. The cover closes the storage section and forms the floor of the vehicle compartment. In this way, the cover that closes the storage section for the battery pack forms the floor of the vehicle compartment, eliminating the need to provide a separate floor panel and making it possible to reduce the number of parts.

[0008] Here, the first rib is provided on the bottom wall of the battery pack. A rocker constituting a part of the vehicle frame extends along the vehicle front-rear direction outside the battery pack in the vehicle width direction, and the first rib transmits a collision load input from the front side or the rear side of the vehicle to the rocker side.

[0009] In other words, in the present invention, the collision load (so-called frontal impact load or so-called rear impact load) input from the front or rear of the vehicle can be transmitted to the rocker side via the first rib, thereby making it possible to distribute the collision load due to a frontal or rear impact.

[0010] The vehicle underbody structure of the invention described in claim 2 is the vehicle underbody structure of the invention described in claim 1, wherein the first rib is provided outside the storage portion and is connected to a first connection portion where the battery pack side and the locker are connected.

[0011] In the vehicle underbody structure according to the invention of claim 2, the first rib is provided outside the storage section, so that the volume of the storage section can be increased compared to when the first rib is provided inside the storage section, and the battery capacity can be increased. Also, the first rib is connected to a first joint that connects the battery pack side to the rocker. Since the first joint has a higher rigidity than other parts, it is possible to reliably transmit the collision load transmitted by the first rib to the rocker side via the first joint.

[0012] Here, the "battery pack side" that is connected to the locker means that it includes other members that are integrated with the battery pack, such as a bracket for connecting to the locker, an undercover that is provided on the lower side of the battery cover, and the like, in addition to the case where the locker and the battery pack are directly connected to each other. Also, the first rib is "connected" to the first connecting portion means that it includes the case where the first rib is connected integrally to the first connecting portion by a bolt or the like, and the case where the first connecting portion is provided on a substantially extended line of the first rib in the vicinity of the first rib.

[0013] The vehicle underbody structure of the invention described in claim 3 is the vehicle underbody structure of the invention described in claim 1, in which a second connection portion at which a cross member extending in the vehicle width direction at the vehicle front side or vehicle rear side is connected to the first rib side, and a third connection portion at which the cross member is connected to a skeleton member extending in the vehicle fore-and-aft direction are provided in positions that approximately overlap in the vehicle width direction in a plan view.

[0014] In the vehicle underbody structure according to the invention recited in claim 3, a cross member extends in the vehicle width direction at the vehicle front side or the vehicle rear side. This cross member and the first rib side are connected via a second connecting portion. Also, a framework member extending in the vehicle front-rear direction is connected to the cross member via a third connecting portion. Here, the second connecting portion and the third connecting portion are provided at positions that substantially overlap in the vehicle width direction in a plan view.

[0015] For example, in the event of a frontal collision of a vehicle, the input frontal collision load is input to the front side member serving as a framework member. Since the front side member is connected to the cross member via the third joint portion, the frontal collision load input to the front side member is transferred to the cross member via the third joint portion.

[0016] In the present invention, the second joint portion, which joins the cross member and the first rib side, is provided at a position that substantially overlaps with the third joint portion in the vehicle width direction in a plan view, so that the front collision load transmitted to the cross member via the front side member and the third joint portion can be efficiently transmitted to the rocker via the second joint portion and the first rib.

[0017] Here, the "first rib side" that is connected to the cross member is meant to include, in addition to the case where the cross member and the first rib are directly connected, other components that are integrated into the battery pack on which the first rib is provided, such as brackets and undercovers for connecting to the cross member.

[0018] The vehicle underbody structure of the invention described in claim 4 is the vehicle underbody structure of the invention described in claim 1, in which a second rib is provided on the outside of the storage section in the bottom wall of the battery pack, for transmitting a collision load input along the vehicle width direction to the rocker side on the opposite side.

[0019] In the vehicle underbody structure according to the invention recited in claim 4, a second rib is provided on the outside of the housing in the bottom wall of the battery pack. This second rib makes it possible to transmit a collision load input along the vehicle width direction to the rocker side on the opposite side.

[0020] The vehicle underbody structure according to the invention recited in claim 5 is the vehicle underbody structure according to the invention recited in claim 4, wherein the first rib and the second rib are connected to each other.

[0021] In the vehicle underbody structure of the invention described in claim 5, the first rib and the second rib are connected, so that the collision load transmitted to the first rib can be transmitted to the rocker and the second rib via the first rib, making it possible to effectively distribute the collision load.

[0022] Here, the first rib and the second rib being "connected" includes not only the case where the first rib and the second rib are integrally joined by bolts, welding, etc., but also the case where the first rib and the second rib are joined via a separate member such as a bracket. Effect of the Invention

[0023] As described above, in the vehicle underbody structure according to the present invention, a transmission path for a collision load can be secured in the event of a frontal or rear collision of the vehicle. [Brief description of the drawings]

[0024] [Figure 1] 1 is a perspective view showing a configuration of a vehicle to which a vehicle underbody structure according to an embodiment of the present invention is applied, viewed from diagonally above the left side. [Diagram 2] 1 is a bottom view showing a partially cutaway state illustrating the configuration of a vehicle to which the vehicle underbody structure according to the present embodiment is applied. FIG. [Diagram 3] 2 is a schematic cross-sectional view taken along the line AA in FIG. 1. [Figure 4] 2 is a schematic cross-sectional view taken along line BB in FIG. 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] The vehicle underbody structure according to the embodiment of the present invention will be described with reference to the drawings. The arrows FR, UP, and LH shown in each drawing indicate the forward direction (traveling direction), upward direction, and leftward direction of the vehicle to which the vehicle underbody structure according to the embodiment of the present invention is applied, respectively. Hereinafter, when the directions of front-rear, left-right, and up-down are simply used for the description, they indicate front-rear in the vehicle front-rear direction, left-right in the vehicle left-right direction (vehicle width direction), and up-down in the vehicle up-down direction, unless otherwise specified. In addition, in each drawing, some members and some symbols may be omitted in order to make the drawings easier to see.

[0026] (Vehicle underbody structure configuration) First, a configuration of a vehicle underbody structure according to an embodiment of the present invention will be described.

[0027] As shown in Figure 1, a vehicle (vehicle body) 12 to which the vehicle undercarriage structure 10 of this embodiment is applied comprises a pair of left and right rockers 16, 18 which each form the vehicle skeleton and extend along the fore-and-aft direction of the vehicle at the lower ends of both ends in the vehicle width direction of the passenger compartment 14 (see Figure 3), a front cross member (cross member) 20 provided along the vehicle width direction at the front ends of the rockers 16, 18, and a rear cross member (cross member) 22 provided along the vehicle width direction at the rear ends of the left and right rockers 16, 18.

[0028] The rear ends of front side members 24 extending along the vehicle fore-and-aft direction are joined to both ends of the front cross member 20 in the vehicle width direction via joints (third joints) 19, 21 made by bolts, welding, etc. In addition, the front ends of rear side members 26 extending along the vehicle fore-and-aft direction are joined to both ends of the rear cross member 22 in the vehicle width direction via joints (third joints) 23, 25 made by bolts, welding, etc.

[0029] The vehicle 12 according to this embodiment is, for example, an electric vehicle (BEV) that runs using the driving force of an electric motor (not shown), and a battery pack 30 that houses a plurality of battery cells 28 that supply driving power to the electric motor is provided under the vehicle 12. The vehicle 12 may also be a plug-in hybrid vehicle (PHEV), a fuel cell vehicle (FCEV), or the like.

[0030] Here, the configuration of the battery pack that constitutes a part of the vehicle lower structure according to this embodiment will be described.

[0031] As shown in Fig. 1, the vehicle underbody structure 10 according to this embodiment includes a battery pack 30. The battery pack 30 is made of a light metal such as an aluminum alloy, and includes a box-shaped battery case 32 that is rectangular in shape with the longitudinal direction of the vehicle in a plan view and has an opening at the top. Note that, in addition to metal, resin members such as carbon fiber reinforced plastic (CFRP) and glass fiber reinforced plastic (GFRP) may also be used. The same applies to a cover 48 and an undercover 60 described below.

[0032] The battery case 32 which constitutes the main body of the battery pack 30 is composed of a bottom wall 34, a front wall 36 which stands upright from the front end of the bottom wall 34 in the fore-and-aft direction of the vehicle, a rear wall 38 which faces the front wall 36 and stands upright from the rear end of the bottom wall 34 in the fore-and-aft direction of the vehicle, and a pair of side walls 40, 42 which stand upright from both ends of the bottom wall 34 in the vehicle width direction and face each other.

[0033] In this embodiment, for example, the distance between the front wall 36 and the rear wall 38 of the battery case 32 is formed to be slightly narrower than the distance between the front cross member 20 and the rear cross member 22. In addition, the distance between the side walls 40 and 42 of the battery case 32 is formed to be slightly narrower than the distance between the rockers 16 and 18. As a result, the battery case 32 in this embodiment can be disposed within the space surrounded by the rockers 16, 18, the front cross member 20, and the rear cross member 22 that constitute the vehicle framework.

[0034] A plurality of thin plate-like battery cells 28 each having a substantially rectangular shape with the vehicle width direction as its longitudinal direction are housed in a storage section 44 of the battery case 32, which is constituted by the bottom wall 34, the front wall 36, the rear wall 38, and the side walls 40, 42, and the battery cells 28 are arranged along the vehicle front-rear direction. Note that, although the storage section 44 is constituted by a single space here, the storage section 44 may be divided into a plurality of sections.

[0035] Furthermore, the storage section 44 of the battery case 32, with the multiple battery cells 28 stored therein, is closed by a cover 48 having a rectangular plate shape in a plan view. This cover 48 is made of a light metal such as an aluminum alloy, has a plate shape with its plate thickness direction in the vertical direction of the vehicle, and is integrated with the battery case 32 by welding or the like, and the cover 48 forms the floor of the vehicle interior 14 (see FIG. 3). The front wall 36 and the rear wall 38 may be integrated with the front cross member 20 and the rear cross member 22, respectively, and the side walls 40 and 42 may be integrated with the rockers 16 and 18, respectively.

[0036] 2, in this embodiment, rectangular column-shaped inclined ribs (first ribs) 50, 52, 54, 56 and cross ribs (second ribs) 58, 59 are respectively provided to protrude from the outside of the storage section 44 in the bottom wall 34 of the battery case 32. The cross ribs 58, 59 are provided on the center side of the battery case 32 in the vehicle front-rear direction, extend along the vehicle width direction of the battery case 32, and are disposed in a state spaced apart from each other.

[0037] The inclined ribs 50, 52 are provided on the front side of the battery case 32 in the vehicle front-rear direction. The inclined ribs 50, 52 are arranged inclined in directions that move away from each other toward the rear side in the vehicle front-rear direction, and the rear ends of the inclined ribs 50, 52 are respectively connected to the cross rib 58 via connecting parts 53, 51 made by bolts, welding, or the like.

[0038] On the other hand, the inclined ribs 54, 56 are provided on the rear side in the vehicle front-rear direction of the battery case 32. The inclined ribs 54, 56 are arranged to incline in directions away from each other as they approach the front side in the vehicle front-rear direction, and the front ends of the inclined ribs 54, 56 are respectively connected to a cross rib 59 via connecting parts 57, 55 made by bolts, welding, or the like.

[0039] An undercover 60 is provided below the inclined ribs 50, 52, 54, 56, etc., and is disposed approximately parallel to the bottom wall 34 of the battery case 32. The undercover 60 is made of a light metal such as an aluminum alloy, has a plate shape with its thickness direction aligned in the vertical direction of the vehicle, and serves to prevent interference with the road surface.

[0040] 2 and 3, a front end portion 60A of the undercover 60 is joined to a lower wall 20A of the front cross member 20 via joints (second joints) 72, 74 formed by bolts, welding, etc. Fig. 3 is a cross-sectional view taken along line AA shown in Fig. 1.

[0041] In this embodiment, the connecting portion 72 is provided on a substantial extension line of the inclined rib 50, and the connecting portion 74 is provided on a substantial extension line of the inclined rib 52. It goes without saying that the front ends of the inclined ribs 50, 52 may be directly connected to the lower wall 20A of the front cross member 20 via the connecting portions 72, 74, respectively.

[0042] In addition, in this embodiment, the connection portions 72, 74 where the undercover 60 and the front cross member 20 are connected, and the connection portions 19, 21 where the front cross member 20 and the front side member 24 are connected, are respectively provided at positions which approximately overlap in the vehicle width direction when viewed in a plan view.

[0043] Meanwhile, the rear end portion 60B of the undercover 60 is joined to the lower wall 22A of the rear cross member 22 via joints (second joints) 76, 78 formed by bolts, welding, or the like. In this embodiment, the joint 76 is provided on a substantial extension of the inclined rib 54, and the joint 78 is provided on a substantial extension of the inclined rib 56. Note that, as with the joints 72, 74, the rear end portions of the inclined ribs 54, 56 may of course be directly joined to the lower wall 22A of the rear cross member 22 via the joints 76, 78, respectively.

[0044] In addition, in this embodiment, the connection portions 76, 78 where the undercover 60 and the rear cross member 22 are connected, and the connection portions 23, 25 where the rear cross member 22 and the rear side member 26 are connected, are provided at positions which approximately overlap in the vehicle width direction when viewed in a plan view.

[0045] Furthermore, one end 60C of the undercover 60 in the vehicle width direction is connected to the lower wall 16B of the rocker 16 via joints (first joints) 80, 82 formed by bolts, welding, or the like. Similarly to the one end 60C, the other end 60D of the undercover 60 in the vehicle width direction is connected to the lower wall 18B of the rocker 18 via joints (first joints) 84, 86 formed by bolts, welding, or the like (see FIG. 4). That is, in this embodiment, the inclined ribs 50, 52, 54, 56 and the cross ribs 58, 59 are disposed between the rockers 16 and 18. Note that FIG. 4 is a cross-sectional view taken along the line BB shown in FIG. 1, but since the rockers 16 and 18 have substantially the same configuration, only the rocker 18 side is shown in FIG. 4 as a representative of both.

[0046] As shown in Fig. 4, the rocker 18 has a closed cross-sectional structure with a closed cross-sectional portion 66 composed of an outer portion 62 and an inner portion 64. In the closed cross-sectional portion 66, an EA portion (shock absorbing portion) 68 formed in a straight line bridging the outer portion 62 and the inner portion 64, and an EA portion 70 formed in a ladder shape are provided. In this way, by providing the EA portions 68, 70 in the closed cross-sectional portion 66 of the rocker 18, it becomes possible to absorb a side impact load inputted in the event of a side impact of the vehicle (so-called "side impact") due to plastic deformation of the EA portions 68, 70. Note that the configuration and shape of the rocker 18 are merely an example, and are not limited to this configuration and shape.

[0047] 2, in this embodiment, the connecting portions 80 and 84 are provided on the approximate extension line of the cross rib 58, the connecting portion 80 is provided on the approximate extension line of the inclined rib 50, and the connecting portion 84 is provided on the approximate extension line of the inclined rib 52. The connecting portions 82 and 86 are provided on the approximate extension line of the cross rib 59, the connecting portion 82 is provided on the approximate extension line of the inclined rib 54, and the connecting portion 86 is provided on the approximate extension line of the inclined rib 56.

[0048] That is, in this embodiment, the joint 80 is provided near the joint 53 between the inclined rib 50 and the cross rib 58, and the joint 84 is provided near the joint 51 between the inclined rib 52 and the cross rib 58. In addition, the joint 82 is provided near the joint 57 between the inclined rib 54 and the cross rib 59, and the joint 86 is provided near the joint 55 between the inclined rib 56 and the cross rib 59.

[0049] In the above embodiment, the inclined ribs 50, 52, the cross ribs 58, etc. are provided to protrude from the outer side of the storage portion 44 in the bottom wall 34 of the battery case 32. However, in the present invention, it is only necessary to ensure a transmission path for the collision load in the event of a frontal or rear-end collision of the vehicle, so that the inclined ribs 50, 52, the cross ribs 58, etc. may be provided to protrude from the inner side of the storage portion 44, although this is not shown in the drawings.

[0050] (Action and effect of vehicle underbody structure) Next, the operation and effects of the vehicle underbody structure according to this embodiment will be described.

[0051] 1 and 2, in this embodiment, the vehicle underbody structure 10 includes a battery case 32 and inclined ribs 50, 52, 54, 56. The battery case 32 includes a storage section 44 and a cover 48, and the storage section 44 stores the battery cells 28 extending along the vehicle width direction and arranged along the vehicle front-rear direction. The cover 48 closes the storage section 44 and forms the floor of the vehicle interior 14.

[0052] In this manner, in this embodiment, the floor that constitutes the floor portion of the vehicle interior 14 is formed by the cover 48 that covers the storage section 44 of the battery case 32, so there is no need to provide a separate floor panel, making it possible to reduce the number of parts.

[0053] Here, the inclined ribs 50, 52, 54, 56 are provided on the bottom wall 34 of the battery case 32. The rockers 16, 18 constituting part of the vehicle frame extend in the front-rear direction of the vehicle outboard of the battery case 32 in the vehicle width direction. The inclined ribs 50, 52 transmit a collision load input from the front side of the vehicle to the rockers 16, 18, and the inclined ribs 54, 56 transmit a collision load input from the rear side of the vehicle to the rockers 16, 18.

[0054] In other words, in this embodiment, by providing inclined ribs 50, 52 and inclined ribs 54, 56 on the bottom wall 34 of the battery case 32, transmission paths for collision loads input from the front and rear sides of the vehicle (so-called frontal impact loads and rear impact loads) are secured, respectively, making it possible to disperse the collision load due to a frontal or rear impact.

[0055] In this embodiment, the inclined ribs 50, 52, 54, 56 are provided on the outside of the storage section 44. As a result, although not shown, in this embodiment, the volume inside the storage section 44 can be increased compared to a case in which the inclined ribs 50, 52, 54, 56 are provided inside the storage section 44, and the battery capacity can be increased. Note that the inclined ribs 50, 52, 54, 56 may be provided inside the storage section 44, in which case the rigidity of the battery case 32 itself can be improved.

[0056] In this embodiment, the inclined ribs 50, 52, 54, 56 provided on the bottom wall 34 of the battery case 32 are connected to coupling parts (first coupling parts) 80, 84, 82, 86 at which the battery case 32 side and the lockers 16, 18 are coupled, respectively.

[0057] Specifically, the joint 80 is provided on an approximate extension line of the inclined rib 50 near the joint 53 between the inclined rib 50 and the cross rib 58, and the joint 84 is provided on an approximate extension line of the inclined rib 52 near the joint 51 between the inclined rib 52 and the cross rib 58. The joint 82 is provided on an approximate extension line of the inclined rib 54 near the joint 57 between the inclined rib 54 and the cross rib 59, and the joint 86 is provided on an approximate extension line of the inclined rib 56 near the joint 55 between the inclined rib 56 and the cross rib 59.

[0058] Generally, the joints that join members have higher rigidity than other portions. Therefore, in this embodiment, the above-described configuration makes it possible to reliably transmit the collision load transmitted by the inclined ribs 50, 54 to the rocker 16 side via the joints 80, 82. Also, it makes it possible to reliably transmit the collision load transmitted by the inclined ribs 52, 56 to the rocker 18 side via the joints 84, 86.

[0059] Furthermore, in this embodiment, a front cross member 20 and a rear cross member 22 extend in the vehicle width direction at the front and rear sides of the vehicle, respectively. The front cross member 20 and the undercover 60 are connected via connecting portions (second connecting portions) 72, 74, and the front cross member 20 and the front side member 24 are connected at connecting portions (third connecting portions) 19, 21.

[0060] In this embodiment, the joints (second joints) 72, 74 are provided at positions that substantially overlap with the joints 19, 21 in the vehicle width direction in a plan view. The rear cross member 22 side is similar to the front cross member 20.

[0061] For example, when a vehicle crashes head-on, the input frontal collision load is input to the front side members 24 serving as framework members. Since the front side members 24 are connected to the front cross member 20 via the connecting portions 19 and 21, the frontal collision load input to the front side members 24 is transmitted to the front cross member 20 via the connecting portions 19 and 21.

[0062] In this embodiment, the connection portions 72, 74 at which the front cross member 20 and the undercover 60 are connected are located at positions which approximately overlap with the connection portions 19, 21 in the vehicle width direction in a planar view, so that the front collision load transmitted to the front cross member 20 via the front side member 24 and the connection portions 19, 21 can be efficiently transmitted to the rockers 16, 18, respectively, via the connection portions 72, 74 and the inclined ribs 50, 52 provided on the bottom wall 34 of the battery case 32.

[0063] In this embodiment, cross ribs 58, 59 extend along the vehicle width direction of the battery case 32 on the bottom wall of the battery case 32. These cross ribs 58, 59 are disposed between the rockers 16 and 18, and therefore can transmit a collision load input along the vehicle width direction to the rocker side on the opposite side.

[0064] Furthermore, in this embodiment, the inclined ribs 50, 52 are connected to the cross rib 58, and the inclined ribs 54, 56 are connected to the cross rib 59. As a result, in this embodiment, a collision load transmitted from the vehicle front side to the inclined ribs 50, 52 can be transmitted to the rockers 16, 18 and the cross rib 58 via the inclined ribs 50, 52, making it possible to effectively distribute the collision load. Also, in this embodiment, a collision load transmitted from the vehicle rear side to the inclined ribs 54, 56 can be transmitted to the rockers 16, 18 and the cross rib 59 via the inclined ribs 54, 56, making it possible to effectively distribute the collision load.

[0065] <Additional Notes> The vehicle underbody structure according to the present invention may be formed by appropriately combining the following configurations.

[0066] (Configuration 1) The vehicle undercarriage structure is provided with a battery pack including a storage section in which battery cells are housed and a cover that closes the storage section and forms a floor of the vehicle compartment, and a first rib that is provided on a bottom wall of the battery pack and transmits a collision load input from the front or rear of the vehicle to a rocker side that forms part of the vehicle frame and extends in the fore-and-aft direction of the vehicle outside the battery pack in the vehicle width direction.

[0067] (Configuration 2) The first rib is provided on the outside of the storage portion and is connected to a first coupling portion where the battery pack and the locker are coupled.

[0068] (Configuration 3) A second connection portion at which a cross member extending in the vehicle width direction at the front or rear side of the vehicle is connected to the first rib side, and a third connection portion at which the cross member is connected to a skeletal member extending in the fore-and-aft direction of the vehicle are provided in positions that approximately overlap in the vehicle width direction in a plan view.

[0069] (Configuration 4) A second rib is provided on the bottom wall of the battery pack on the outer side of the housing portion to transmit a collision load input along the vehicle width direction to the rocker side on the opposite side.

[0070] (Configuration 5) The first rib and the second rib are connected to each other.

[0071] In addition, the present invention can be implemented in various modifications without departing from the spirit and scope of the present invention. Furthermore, the scope of the present invention is not limited to the above-described embodiment. [Explanation of symbols]

[0072] 10 Vehicle underbody structure 12 Vehicles 14 Cabin 16 Rocca 18 Rocca 19 Joint part (3rd joint part) 20 Front cross member (cross member) 21 Joint part (3rd joint part) 22 Rear cross member (cross member) 23 Joint part (3rd joint part) 24 Front side member (framework member) 25 Joint part (3rd joint part) 26 Rear side member (framework member) 28 Battery Cells 30 Battery Pack 34 Bottom Wall 44 Storage unit 48 Cover 50 Inclined rib (first rib) 52 Inclined rib (first rib) 54 Inclined rib (first rib) 56 Inclined rib (first rib) 58 Cross rib (second rib) 59 Cross rib (second rib) 72 Joint part (second joint part) 74 Joint part (second joint part) 76 Joint part (second joint part) 78 Joint (Second Joint) 80 Joint (First Joint) 82 Joint (First Joint) 84 Joint (First Joint) 86 Joint (First Joint)

Claims

1. a battery pack including a storage section in which a battery cell is stored and a cover that closes the storage section and constitutes a floor section of a vehicle interior; a first rib that is provided on a bottom wall of the battery pack and that transmits a collision load input from the front side or the rear side of the vehicle to a rocker side that constitutes a part of a vehicle frame and extends along a front-rear direction of the vehicle on an outer side of the battery pack in the vehicle width direction; A vehicle undercarriage comprising:

2. 2. The vehicle underbody structure according to claim 1, wherein the first rib is provided outside the storage portion and is connected to a first connecting portion at which the battery pack and the locker are connected.

3. The vehicle undercarriage structure of claim 1, wherein a second joint portion at which a cross member extending in the vehicle width direction at the front or rear side of the vehicle is connected to the first rib side, and a third joint portion at which a skeletal member extending in the fore-and-aft direction of the vehicle is connected to the cross member are provided at positions that approximately overlap in the vehicle width direction when viewed in a plane.

4. 2. The vehicle underbody structure according to claim 1, wherein a second rib is provided on an outer side of the storage portion in the bottom wall of the battery pack to transmit a collision load input along the vehicle width direction to the opposite rocker side.

5. The vehicle underbody structure according to claim 4 , wherein the first rib and the second rib are connected to each other.

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