Lower structure of a vehicle

Abstract

To suppress application of excessive tension on a high-voltage cable without increasing the length of the high-voltage cable, by suppressing a rotation behavior of a battery unit in the event of side collision.SOLUTION: A lower part structure for a vehicle includes: a battery unit 20L provided below a vehicle body floor 4; a skeleton member 11 extending in a longitudinal direction outside the battery unit 20L in a vehicle width direction; a high voltage cable 14 extending forward from a front part of the battery unit 20L; and a fixing member 30 fixing a rear part of the battery unit 20L to the skeleton member 11; wherein the fixing member 30 is configured to be broken when a collision load inward in the vehicle width direction is input to a position that is further forward than a gravity center of the first battery unit 20L.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] This invention relates to , B the underbody structure of a vehicle configured to mount a battery unit under the floor.

Background Art

[0002] Conventionally, as disclosed in Patent Document 1, a BEV (battery electric vehicle) structure is known in which a battery unit is disposed under the vehicle floor and side sills, which are vehicle body strength members located on both left and right sides in the vehicle width direction of a floor panel, are configured to absorb side impact load energy during a side impact of the vehicle.

[0003] Among BEV-structured vehicles, in the case of a PHEV (plug-in hybrid electric vehicle) vehicle, an engine mounted at the front of the vehicle is used for power generation or driving. For this reason, in a PHEV vehicle, due to the arrangement of an exhaust pipe that extends rearward of the vehicle along a floor tunnel that extends in the front-rear direction under the vehicle floor from the engine, it is necessary to arrange battery units on each side in the vehicle width direction with a space therebetween across the floor tunnel.

[0004] When such a structure is adopted, when a collision load acting inward in the vehicle width direction is input in front of the vehicle with respect to the center of gravity position of the battery unit, such as in a pole side impact, the side sill deforms in a V shape in a plan view of the vehicle, and the side impact load is input to a local part in front of the center of gravity position of the battery unit, causing the front of the battery unit to rotate and displace inward in the vehicle width direction.

[0005] When there is a high-voltage cable connecting the above-described battery unit and a high-voltage device such as an inverter in front of the battery unit, there has been a concern that the high-voltage cable may be strongly pulled during the rotation and displacement inward in the vehicle width direction in front of the battery unit.

[0006] In order to avoid such concerns, it is conceivable to set the length of the high-voltage cable to be sufficiently long. However, when the high-voltage cable is lengthened, a new problem arises in that the electrical resistance increases accordingly.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0008] The present invention has been made in view of such problems, and by suppressing the rotational behavior of the battery unit during a side collision, it is possible to suppress excessive tension from being applied to the high-voltage cable without increasing the length of the high-voltage cable. An object of the present invention is to provide a vehicle underbody structure.

Means for Solving the Problems

[0009] The underbody structure of the vehicle according to the present invention includes a battery unit provided below a floor panel constituting a vehicle body floor, a skeletal member extending in the front-rear direction outside the battery unit in the vehicle width direction, a high-voltage cable extending forward from the front portion of the battery unit, and the rear portion of the battery unit and the side surface on the outer side in the vehicle width direction and a fixing member for fixing the battery unit to the skeletal member, wherein the fixing member is configured to be breakable when a collision load in the vehicle width direction is input to a position in front of the center of gravity position of the battery unit.

[0010] In addition, the lower structure of the vehicle of the present invention includes a battery unit provided below a floor panel constituting a vehicle body floor, a skeleton member extending in the front-rear direction on the outer side in the vehicle width direction from the battery unit, a high-voltage cable extending forward from the front portion of the battery unit, and a fixing member for fixing the rear portion of the battery unit to the skeleton member. The fixing member is configured to be breakable when a collision load in the vehicle width direction is input at a position forward of the center-of-gravity position of the battery unit. The fixing member has a vehicle body fastening portion, first and second battery fastening portions spaced apart in the front-rear direction, and a hole portion formed between the first battery fastening portion and the second battery fastening portion. The first battery fastening portion is located forward of the second battery fastening portion, The longitudinal length in the front-rear direction between the vehicle body fastening portion and the first battery fastening portion is longer than the longitudinal length in the front-rear direction between the vehicle body fastening portion and the second battery fastening portion.

[0011] According to the above configuration, when a collision load in the vehicle width direction, i.e., a side collision load, is input to the front position of the battery unit, the skeletal member bends and deforms inward in the vehicle width direction, causing a behavior of pushing the front part of the battery unit inward in the vehicle width direction. However, since the fixing member breaks, it is possible to suppress a rotational behavior in which the front part of the battery unit is largely displaced inward in the vehicle width direction following the deformation of the skeletal member.

[0012] Therefore, during a side collision, it is possible to suppress an excessive tension from being applied to the high-voltage cable extending forward along with the above-described rotational behavior of the battery unit. As a result, since it is not necessary to form the high-voltage cable to be excessively long compared to its actual length, it is possible to suppress an increase in the electrical resistance of the high-voltage cable.

[0013] Further, as described above, the fixing member has a configuration including a vehicle body fastening portion, first and second battery fastening portions spaced apart in the front-rear direction, and a hole portion formed between the first battery fastening portion and the second battery fastening portion.

[0014] According to the above configuration, the load transmission path transmitted from the vehicle body fastening portion to the battery side can be divided into each side with the hole portion provided between the first battery fastening portion and the second battery fastening portion. Therefore, at the time of a side collision, the load input from the vehicle body to the fixing member via the vehicle body fastening portion can be concentrated in the vicinity of the first and second battery fastening portions. Therefore, at the time of a side collision, the vicinity of the first battery fastening portion and the vicinity of the second battery fastening portion can be surely broken.

[0015] Further, as described above, the first battery fastening portion is located forward of the second battery fastening portion, and the longitudinal length in the front-rear direction between the vehicle body fastening portion and the first battery fastening portion is longer than the longitudinal length in the front-rear direction between the vehicle body fastening portion and the second battery fastening portion.

[0016] According to the above configuration, since the longitudinal length (moment length) between the vehicle body fastening portion and the first battery fastening portion is longer than the longitudinal length (moment length) between the vehicle body fastening portion and the second battery fastening portion, at the time of a side collision, the moment load can be concentrated in the vicinity of the first battery fastening portion rather than in the vicinity of the second battery fastening portion.

[0017] Therefore, it is possible to break the vicinity of the first battery fastening part and the vicinity of the second battery fastening part step by step in this order, and as a result, it is possible to surely break both the vicinity of the first battery fastening part and the vicinity of the second battery fastening part.

[0018] As an aspect of the present invention, the skeletal member is a side sill extending in the front-rear direction outside the vehicle width direction from the floor panel.

[0019] According to the above configuration, even when the side sill bends and deforms inward in the vehicle width direction during a side collision, since the fixing member fixed to the side sill breaks, it is possible to suppress the above-described rotational behavior in which the battery unit is displaced following the deformation of the side sill. 。

[0020] ThisAs an aspect of the invention, a side sill extending in the longitudinal direction outside the vehicle width direction from the floor panel, a floor frame and a rear side frame adjacent to the side sill on the inner side in the vehicle width direction and extending in the longitudinal direction, wherein the floor frame is provided in front of the rear side frame, a rear portion of the floor frame and a front portion of the rear side frame are joined to each other, and the skeletal member is at least one of the floor frame and the rear side frame.

[0021] According to the above configuration, even when the side sill is bent and deformed inward in the vehicle width direction during a side impact, since a fixing member fixed to at least one of the floor frame and the rear side frame breaks, the above-described rotational behavior in which the battery unit is displaced following the deformation of the side sill can be suppressed. 。

[0022] This As an aspect of the invention, the second battery fastening portion may be configured to be located below the first battery fastening portion.

[0023] According to the above configuration, a desired fracture line for breaking the fixing member during a side impact is a line that linearly connects the vicinity of each vehicle body fastening portion of the first battery fastening portion and the second battery fastening portion. However, as described above, since the second battery fastening portion is located below the first battery fastening portion, the fixing member can be configured not to have a fastening portion at a position closer to the vehicle body fastening portion side than the fracture line. For this reason, during a side impact, the stress input from the vehicle body fastening portion to the rear bracket is not dispersed to the fastening portion located closer to the vehicle body fastening portion side than the fracture line, and the stress can be concentrated on the first battery fastening portion.

[0024] As an aspect of this invention, it may be configured to have a strength reducing portion in the vicinity of the vehicle body fastening portion side of the first battery fastening portion.

[0025] According to the above configuration, by having a strength reduction portion in the side impact load transmission path from the vehicle body fastening portion to the first battery fastening portion, near the first battery fastening portion, it is possible to surely break the vicinity of the first battery fastening portion during a side impact and control the breaking position.

[0026] As an aspect of the present invention, the strength reduction portion is a portion where the path width is the smallest or / and the wall thickness is the thinnest in the load transmission path that shortest connects the vehicle body fastening portion and the first battery fastening portion.

[0027] According to the above configuration, during a side impact, it is possible to surely and easily break the vicinity of the first battery fastening portion and easily control the breaking position.

[0028] As an aspect of the present invention, the fixing member is provided with a flange portion bent with respect to the load transmission path along at least one edge in the path width direction of the load transmission path, and a configuration may be adopted in which the end portion on the first battery fastening portion side of the flange portion is located near the strength reduction portion.

[0029] According to the above configuration, in the load transmission path, a rigidity difference is created between the vicinity of the first battery fastening portion and other portions, so that it is possible to surely break the vicinity of the first battery fastening portion during a side impact.

[0030] In addition, the durability (rigidity) against vibration input from the battery during normal driving can be enhanced. Therefore, it is possible to achieve both reliable breakage of the vicinity of the first battery fastening portion during a side impact and durability against vibration input from the battery during normal driving.

[0031] Note that the path width direction indicates a direction orthogonal to the load transmission path connecting the fastening portions in a side view.

Advantages of the Invention

[0032] According to the above configuration, during a side collision, by suppressing the rotational behavior of the battery unit, it is possible to suppress excessive tension from being applied to the high-voltage cable without increasing the length of the high-voltage cable.

Brief Description of the Drawings

[0033]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Embodiments for Carrying Out the Invention

[0034] As an embodiment of the present invention, the lower structure of the vehicle 1 of this embodiment applied to a plug-in hybrid vehicle (PHEV) will be described below with reference to the following drawings. Also, in the figure, the arrow F indicates the front direction of the vehicle 1, the arrow R indicates the right direction of the vehicle 1, the arrow L indicates the left direction of the vehicle 1, and the arrow U indicates the upward direction of the vehicle, respectively.

[0035] As shown in FIGS. 1 and 2, the vehicle 1 of the present embodiment includes a vehicle body 2 and a battery unit 20 disposed under the floor of the vehicle body 2 and the like. In the vehicle body 2, in front of the passenger compartment, there is appropriately a power unit room (not shown) that houses a power unit (not shown) composed of an engine or a motor (both not shown) used for power generation or driving.

[0036] As shown in FIGS. 1 and 2, a floor panel 4 constituting the vehicle body floor is disposed below the passenger compartment in the vehicle body 2.

[0037] The floor panel 4 includes a front floor panel 5 and a rear floor panel 6, and the front floor panel 5 and the rear floor panel 6 are connected to each other on each front and rear side via a kick-up portion (not shown).

[0038] The front floor panel 5 bulges upward (into the passenger compartment) at the center in the vehicle width direction and has a tunnel portion 7 (also referred to as "floor tunnel 7") extending in the longitudinal direction of the vehicle 1 integrally or integrally formed. This tunnel portion 7 is the center of the vehicle body rigidity and is formed in the longitudinal direction over substantially the entire length of the floor panel 4.

[0039] As shown in FIGS. 1 and 2, left and right tunnel side members 8 extending in the longitudinal direction of the vehicle body 2 are provided below the floor panel 4 along the lower edges on both left and right sides of the tunnel portion 7. Closed cross-sections 8s extending in the longitudinal direction of the vehicle 1 are respectively formed between the tunnel side members 8 and the above-described floor panel 4.

[0040] Also, as shown in the same figure, side sills 9 extending in the longitudinal direction are connected to both outer sides (left and right sides) in the width direction of the above-described floor panel 4. The side sill 9 is a skeletal member having a closed cross-section 9s formed by joining a side sill inner 9a (see FIG. 1) and a side sill outer 9b and extending over substantially the entire length in the longitudinal direction of the floor panel 4.

[0041] Below the floor panel 4, between the side edge of the floor panel 4 and the tunnel portion 7, specifically, between the side sill inner 9a and the tunnel side member 8, a floor frame 10 is provided as a left and right skeletal member that protrudes downward and extends in the front-rear direction. Between the floor frame 10 and the floor panel 4, a closed cross-section 10s extending in the front-rear direction is formed.

[0042] The rear portion 10r of the floor frame 10 is adjacent to the side sill 9 on the inner side in the vehicle width direction and extends in the front-rear direction substantially parallel to the side sill 9. As described above, the rear floor panel 6 is disposed rearward of the front floor panel 5. On both outer sides in the vehicle width direction of the rear floor panel 6, rear side frames 11 extending in the front-rear direction of the vehicle 1 are disposed. The front portion 11f of the rear side frame 11 extends forward to reach the outer side in the vehicle width direction of the rear portion of the front floor panel 5. That is, the front portion 11f of the rear side frame 11 is adjacent to the rear portion of the side sill 9 on the inner side in the vehicle width direction and extends in the front-rear direction substantially parallel to the side sill 9. And the front end of the rear side frame 11 is joined to the rear end of the floor frame 10.

[0043] The front portion 10f of the floor frame 10 is inclined so as to be located on the inner side in the vehicle width direction in the front and extends linearly. Although not shown, the front end is joined to the rear end of the front side frame as a skeletal member extending in the front-rear direction on both sides of the power unit room in front of the passenger compartment in the vehicle body 2.

[0044] Also, as shown in FIG. 2, at an intermediate position in the front-rear direction of the side sill 9, a center pillar 12 (only shown on the left side of the vehicle body 2) extending upward from the intermediate position is provided. The center pillar 12 includes a center pillar outer 12a and a center pillar inner (not shown) and is a skeletal member in which a closed cross-section 12s extending in the vertical direction is formed.

[0045] An exhaust port (not shown) provided in an engine (not shown) mounted in front of the passenger compartment in the vehicle body 2 is connected to an exhaust device 60 (see FIG. 1) via an exhaust manifold (not shown). The exhaust device 60 is disposed continuously in the longitudinal direction of the vehicle 1 at a position below the lower end of the floor panel 4.

[0046] As shown in FIG. 1, the exhaust device 60 includes various exhaust system members 61 such as a catalyst unit, a silencer, and a tail pipe, and an exhaust pipe 62 that is disposed between the various exhaust system members 61 and connects the exhaust system members 61 adjacent to each other in the front-rear direction. Note that reference numeral 61a in the figure indicates a catalyst unit among the exhaust system members 61. Also, in FIG. 2, the exhaust device 60 is not shown.

[0047] The exhaust device 60 composed of these elements is disposed continuously in the longitudinal direction of the vehicle 1 at a position below the lower end of the floor panel 4. Specifically, as shown in FIG. 1, the exhaust device 60 is routed so as to bypass to one side (the right side in this example) outside the vehicle width direction from the tunnel portion 7 at the front portion of the front floor panel 5 and the rear portion of the rear floor panel 6 in the front-rear direction. On the other hand, the exhaust device 60 is routed directly below the tunnel portion 7 at the rear portion of the front floor panel 5 in the front-rear direction.

[0048] Below the floor panel 4, insulators 65, 66, and 67 are disposed along the longitudinal direction (exhaust path) of the exhaust device 60. The insulators 65, 66, and 67 are formed in a convex shape upward so that the orthogonal cross-section in the longitudinal direction of the exhaust device 60 opens downward. And the insulators 65, 66, and 67 house the exhaust device 60 therein to prevent the heat damage of the exhaust device 60 from reaching the surroundings.

[0049] The insulators 65, 66, 67 include a front insulator 65, a middle insulator 66, and a rear insulator 67. These insulators 65, 66, 67 are formed separately from each other and are attached to the vehicle body 2 in a state where they are connected so as to be continuous in the front-rear direction.

[0050] As shown in FIGS. 1 and 2, the battery unit 20 is disposed below the rear part of the front floor panel 5. However, in a plug-in hybrid vehicle (PHEV) such as the vehicle 1 of the present embodiment, which can be directly charged from a commercial power outlet for electrical energy, since the battery is large and has a large capacity, in order to cope with this, the battery unit 20 is disposed on the lower side of the floor panel 4, separated from each other on the left and right sides with the tunnel portion 7 therebetween. Here, among the battery units 20 on the left and right sides, the left battery unit 20L is also referred to as the "first battery unit 20L", and the right battery unit 20 is also referred to as the "second battery unit 20R". Note that the first battery unit 20L and the second battery unit 20R are separated from each other on the left and right sides with the tunnel portion 7 therebetween, but are electrically connected to each other (not shown).

[0051] As shown in FIGS. 1 and 2, both the first and second battery units 20L, 20R are configured as battery packs each having a battery module 21 (battery module) and a battery case 22 as a battery case for housing the battery module 21. The vehicle 1 travels using the electrical energy stored in the battery module 21 housed in the battery case 22 in addition to the drive of the engine.

[0052] Although not shown, the battery module 21 is configured by laminating a plurality of battery cells formed in a flat plate shape extending in the vertical direction and the front-rear direction in the vehicle width direction. Examples of the battery cell include secondary batteries such as lithium ion batteries and nickel metal hydride batteries.

[0053] The battery case 22 is formed in a box shape by a tray 221 that supports the battery module 21 from below and a lid 222 that covers the battery module 21 from above (only shown on the left side of the vehicle 1). A flange portion 221a is formed on the outer peripheral edge of the tray 221 in a plan view, and in a state where the battery module 21 is housed inside, the flange portion 221a is fastened to the outer peripheral edge of the lid 222 in a plan view.

[0054] Also, as shown in FIGS. 1 and 2, the first and second battery units 20L and 20R are disposed on the inner side in the vehicle width direction with respect to the rear portions 10r of the floor frames 10 and the front portions 11f of the rear side frames 11 corresponding to the left and right sides, respectively, and on the outer side in the vehicle width direction with respect to the tunnel portion 7.

[0055] Also, the first and second battery units 20L and 20R are each fastened and fixed at a plurality of locations using bolts and the like via brackets 15, 30, etc. to a plurality of the aforementioned skeleton members in which the battery case 22 is disposed around.

[0056] Specifically, the first and second battery units 20L and 20R are each fixed to the tunnel portion 7 as a skeleton member adjacent on the inner side in the vehicle width direction via a bracket (not shown) on the inner side in the vehicle width direction, although not shown in the figure.

[0057] On the other hand, the first and second battery units 20L and 20R are each fixed to the rear portion 10r of the floor frame 10 as a skeleton member adjacent on the outer side in the vehicle width direction via an intermediate bracket 15 on the outer side in the vehicle width direction, and are also fixed to the front portion 11f of the rear side frame 11 via rear side brackets 30L and 30R. The specific structures of the above-mentioned intermediate bracket 15 and rear side brackets 30L and 30R will be described later.

[0058] Further, the above-described intermediate insulator 66 is located between the first and second battery units 20L and 20R below the tunnel portion 7. And, as shown in FIGS. 1 and 2, below the above-described intermediate insulator 66 and between the first and second battery units 20L and 20R, a connecting member 24 for connecting these first and second battery units 20L and 20R to each other is disposed.

[0059] Specifically, the connecting member 24 extends in the vehicle width direction so as to close the intermediate insulator 66 opening downward from below, and connects between the inner side in the vehicle width direction of the bottom surface of the first battery unit 20L and the inner side in the vehicle width direction of the bottom surface of the second battery unit 20R in the vehicle width direction.

[0060] Below the front portion of the floor panel 4, that is, in front of the first battery unit 20L, an inverter 13 as a high-voltage device is provided. The inverter 13 is a converter that mutually converts the power of the DC circuit in which the battery unit 20 is interposed and the power of the AC circuit in which the motor is interposed.

[0061] The inverter 13 is disposed between the front portion of the floor frame 10 and the front portion of the tunnel side member 8 on one side in the vehicle width direction (in this example, the left side of the vehicle 1), and is attached and fixed to the front portion 10f of these floor frames 10 and the front portion of the tunnel side member 8.

[0062] The first battery unit 20L and the inverter 13 are connected to each other via a high-voltage cable 14 (high-voltage harness). In the present embodiment, the front plug 14f of the high-voltage cable 14 is connected to the rear portion of the inverter 13, and the rear plug 14r is connected to the front portion of the first battery unit 20L (specifically, the front portion of the first battery unit 20L from the center of gravity position), and extends substantially in the front-rear direction between the front portion of the first battery unit 20L and the rear portion of the inverter 13.

[0063] Accordingly, when the motor (not shown) is driven, AC driving power is supplied from the first and second battery units 20L and 20R to the motor side via the high-voltage cable 14, and when the motor generates electricity, DC charging power is supplied from the motor side to the first and second battery units 20L and 20R via the high-voltage cable 14, respectively.

[0064] Although not shown, in this embodiment, the front of the battery unit 20 on the lower surface of the floor panel 4 is covered by an under cover. The under cover (not shown) is provided in the lower side of the front part of the floor panel 4, in one region and the other region in the vehicle width direction with respect to the insulator 65. These pair of under covers are both arranged at a height substantially flush with the lower surface of the battery unit 20 and the lower end of the insulator 65, and the portions adjacent to these are joined to the lower surface of the battery unit 20 and the lower end of the insulator 65 (not shown).

[0065] Also, as shown in FIGS. 1 and 2, the above-described intermediate brackets 15 are provided in a pair on the left and right, and both are located at positions corresponding to the center pillar 12 (see FIG. 2) in the front-rear direction (substantially the middle position in the front-rear direction of the side sill 9) and on the outer side in the vehicle width direction corresponding to each of the first and second battery units 20L and 20R. The intermediate bracket 15 is formed in a substantially L shape by a battery-side attachment piece 151 extending in the vertical direction in a front-rear direction orthogonal cross-sectional view and a vehicle-body-side attachment piece 152 extending outward in the vehicle width direction from the lower part of the battery-side attachment piece 151.

[0066] Then, the intermediate bracket 15 is fastened and fixed to the outer side surface in the vehicle width direction of the battery case 22 by bolts or the like with the battery-side attachment piece 151, and the vehicle-body-side attachment piece 152 is fastened and fixed to the rear part 10r of the floor frame 10 by bolts or the like.

[0067] In addition, the above-described rear brackets 30L and 30R are provided on each of the left and right sides, and both are brackets for fixing the battery case 22 to the vehicle body 2 (the lower surface portion of the front portion 11f of the rear side frame 11) at the rear portion of the battery case 22 (specifically, behind the center of gravity position of the battery case 22) and on the outer side surface in the vehicle width direction. They are formed by bending a steel plate or the like by press forming or the like.

[0068] Among the pair of left and right rear brackets 30L and 30R, the rear bracket 30L on the left side of the vehicle is a bracket for fixing the rear portion of the first battery unit 20L to the vehicle body 2 (the lower surface portion of the front portion 11f of the rear side frame 11) from the outer side in the vehicle width direction, and corresponds to the fixing member of the present invention.

[0069] When a collision load in the vehicle width direction inward from the left side of the vehicle 1 is input to this rear bracket 30L at a position in front of the center of gravity position of the first battery unit 20L (for example, a position corresponding to the center pillar 12 in the front-rear direction) (that is, at the time of a side collision from the left side of the vehicle 1), it is configured to be breakable.

[0070] On the other hand, among the pair of left and right rear brackets 30L and 30R, the rear bracket 30R on the right side of the vehicle is formed more robustly than the rear bracket 30L on the left side of the vehicle, giving priority to the durability (rigidity) against the vibration input from the second battery unit 20R during normal driving.

[0071] Hereinafter, the configuration of the rear bracket 30L on the left side of the vehicle will be described. As shown in FIGS. 3 to 5, the rear bracket 30L is integrally formed by a vehicle width outward extending piece 31 extending in the vehicle width direction and a downward extending piece 32 extending downward from the inner end in the vehicle width direction of the vehicle width outward extending piece 31. The bent portion 36 located at the corner portion between the vehicle width outward extending piece 31 and the downward extending piece 32 is formed over substantially the entire length in the front-rear direction of the rear bracket 30L.

[0072] The vehicle-width outwardly extending piece 31 is provided with a front flange portion 33 at the front part, a vehicle body side mounting portion 34 at the middle part in the front-rear direction, and a rear flange portion 35 at the rear part, and they are formed continuously in the front-rear direction. The front flange portion 33, the vehicle body side mounting portion 34, and the rear flange portion 35 all extend outward in the vehicle-width direction and are formed in a roof-like shape with respect to the downwardly extending piece 32. The vehicle body side mounting portion 34 is formed to protrude outward in the vehicle-width direction more than the front flange portion 33 and the rear flange portion 35.

[0073] The front flange portion 33 is inclined so as to be positioned downward in front along the bent portion 36 from the front end of the vehicle body side mounting portion 34 and extends linearly. On the other hand, the rear flange portion 35 extends rearward along the bent portion 36 from the rear end of the vehicle body side mounting portion 34.

[0074] A pin insertion hole 341 penetrating in the vertical direction so that a pin P (see FIGS. 3 and 4) can be inserted is formed in the front side portion of the vehicle body side mounting portion 34, and a bolt insertion hole 342 penetrating in the vertical direction so that a bolt B34 (see the same figure) can be inserted is formed in the rear side portion of the vehicle body side mounting portion 34.

[0075] Thereby, the rear bracket 30L is positioned on the vehicle body 2 (the lower surface of the front portion 11f of the rear side frame 11) using the pin P in the pin insertion hole 341 of the vehicle body side mounting portion 34. Further, the rear bracket 30L is fastened and fixed to the vehicle body 2 (the same lower surface) using a bolt B34 or the like in the bolt insertion hole 342 of the vehicle body side mounting portion 34 in such a positioned state. That is, the bolt B34 inserted into the bolt insertion hole 342 of the vehicle body side mounting portion 34 is formed as a vehicle body fastening portion B34 that fastens to the vehicle body 2.

[0076] The lower extension piece 32 in the rear bracket 30L has a battery side attachment piece 41 formed from the front part to the middle part in the front-rear direction, and a rear extension piece 47 formed at the rear part. These battery side attachment piece 41 and rear extension piece 47 are continuously formed across the front-rear direction. The battery side attachment piece 41 and the rear extension piece 47 both extend vertically downward from the inner end in the vehicle width direction of the vehicle width outer extension piece 31 via the bending part 36, but the battery side attachment piece 41 is formed to protrude downward more than the rear extension piece 47.

[0077] The above-mentioned rear extension piece 47 extends substantially horizontally in a rear view of the vehicle from the base of the battery side attachment piece 41 (that is, the joint part of the upper edge side 41u and the rear edge side 41r to be described later) toward the rear of the vehicle 1. The rear extension piece 47 is formed with a bending part 46 at the middle part in the front-rear direction so that the rear part (tip part) faces slightly inward in the vehicle width direction with respect to the front part (base part). A through hole 48 for attaching a harness (not shown) is formed at the rear part of the rear extension piece 47.

[0078] As shown in FIGS. 3 to 5, the battery side attachment piece 41 includes an upper edge side 41u that extends in a substantially straight line while being inclined in a side view of the vehicle so as to be positioned downward in the front, a rear edge side 41r that extends linearly while being inclined at a steeper gradient than the upper edge side 41u in a side view of the vehicle so as to be positioned downward in the front at the rear edge of the battery side attachment piece 41, a front edge side 41f that extends linearly vertically downward from the front lower end of the upper edge side 41u, and a lower edge side 41d that extends linearly in the front-rear direction so as to connect the front lower end of the rear edge side 41r and the lower end of the front edge side 41f, and is integrally formed. Note that since the lower end of the front edge side 41f and the front lower end of the rear edge side 41r are located at substantially the same height, the lower edge side 41d extends horizontally in the front-rear direction.

[0079] In other words, a hole part 41h penetrating in the vehicle width direction (plate thickness direction) is formed at the central part in a side view of the battery side attachment piece 41. The hole part 41h is defined by the upper edge side 41u, the rear edge side 41r, the front edge side 41f, and the lower edge side 41d located on the outer periphery of the battery side attachment piece 41.

[0080] In the battery side attachment piece 41 described above, a plurality (three in this example) of bolt insertion holes 42, 43, 44 are formed so as to penetrate in the vehicle width direction (plate thickness direction) through which bolts B42, B43, B44 can be inserted.

[0081] In the present embodiment, the bolt insertion hole 42 is formed at the upper part of the front edge 41f of the battery side attachment piece 41, the bolt insertion hole 43 is formed at the lower end of the rear edge 41r of the battery side attachment piece 41 (the corner part of the rear edge 41r and the lower edge 41d), and the bolt insertion hole 44 is formed at the lower end of the front edge 41f of the battery side attachment piece 41 (the corner part of the front edge 41f and the lower edge 41d), and they are respectively set as the first bolt insertion hole 42, the second bolt insertion hole 43, and the third bolt insertion hole 44.

[0082] Then, as shown in FIGS. 3 and 4, the above-described rear bracket 30L is fastened and fixed to the outer side surface in the vehicle width direction of the battery case 22 using bolts B42, B43, B44, etc. at each of the bolt insertion holes 42, 43, 44 of the battery side attachment piece 41. That is, the bolt B42 inserted through the first bolt insertion hole 42 is formed as a first battery fastening portion B42 for fastening to the battery case 22. Similarly, the bolt B43 inserted through the second bolt insertion hole 43 is formed as a second battery fastening portion B43 for fastening to the battery case 22, and the bolt B44 inserted through the third bolt insertion hole 44 is formed as a third battery fastening portion B44 for fastening to the battery case 22.

[0083] The first to third battery fastening portions B42, B43, B44 are all located below the vehicle body fastening portion B34. Also, the first battery fastening portion B42 and the third battery fastening portion B44 are located in front of the second battery fastening portion B43, and the second battery fastening portion B43 and the third battery fastening portion B44 are located below the first battery fastening portion B42.

[0084] Furthermore, in the present embodiment, the third battery fastening portion B44 is located directly below the first battery fastening portion B42 and is located at substantially the same height as the second battery fastening portion B43.

[0085] Also, as shown in FIGS. 4 and 6, the first and second battery fastening portions B42 and B43 are provided such that the longitudinal length L1' in the front-rear direction between the vehicle body fastening portion B34 and the first battery fastening portion B42 (the length of the front-rear direction component of the length L1 between the vehicle body fastening portion B34 and the first battery fastening portion B42) is longer than the longitudinal length L2' in the front-rear direction between the vehicle body fastening portion B34 and the second battery fastening portion B43 (the length of the front-rear direction component of the length L2 between the vehicle body fastening portion B34 and the second battery fastening portion B43).

[0086] Furthermore, when a collision load in the vehicle width direction inward from the left side of the vehicle 1 is input to the battery side attachment piece 41 of the rear bracket 30L at a position in front of the center of gravity position of the first battery unit 20L (for example, a position corresponding to the center pillar 12 (see FIG. 2) in the front-rear direction) (that is, when the vehicle 1 is side-collided from the left side), it is configured to be breakable.

[0087] Specifically, as shown in FIGS. 3 to 5, a constricted portion 45 as a strength reduction portion is formed at a vicinity portion on the vehicle body fastening portion B34 side (in this example, the corner portion (boundary portion) of the upper edge 41u and the front edge 41f) in the first battery fastening portion B42. Specifically, in the constricted portion 45, at least one edge in the width direction of the vicinity portion on the vehicle body fastening portion B34 side in the first battery fastening portion B42 (in this example, the edge in front of and above the corner portion of the upper edge 41u and the front edge 41f) is formed in a concave shape rearward and downward. Thereby, the constricted portion 45 is formed as a strength reduction portion to be locally narrower in width than the peripheral portion, and is formed as a vulnerable portion (narrow-width portion) that preferentially breaks during a side collision.

[0088] Here, when a side collision occurs from the left side of the vehicle 1, a skeletal member (outer skeletal member) such as the side sill 9 located on the outside in the vehicle width direction (the left side of the vehicle 1 in this example) relative to the first battery unit 20L bends and deforms inward in the vehicle width direction, and a behavior occurs in which the front portion of the first battery unit 20L is pushed inward in the vehicle width direction. Along with this, the rear portion of the first battery unit 20L is pulled outward in the vehicle width direction by the front portion 11f of the rear side frame 11 via the rear side bracket 30L.

[0089] Due to this, between each of the first and second battery fastening portions B42 and B43 and the vehicle body fastening portion B34 in the rear side bracket 30L, a load transmission path that connects these in the shortest way is configured.

[0090] As shown in FIG. 4, among these load transmission paths, the load transmission path between the first battery fastening portion B42 and the vehicle body fastening portion B34 is set as the first load transmission path P1, and the load transmission path between the second battery fastening portion B43 and the vehicle body fastening portion B34 is set as the second load transmission path P2. That is, the first load transmission path P1 is formed along the upper edge 41u of the battery side attachment piece 41, and the second load transmission path P2 is formed along the rear edge 41r of the battery side attachment piece 41.

[0091] Here, the front side flange portion 33 extends along the upper edge of the first load transmission path P1 formed along the upper edge 41u of the battery side attachment piece 41.

[0092] However, the front lower end 33a (the end on the first battery fastening portion B42 side) of the front side flange portion 33 is located at the upper and rear edge of the constriction portion 45. That is, the front side flange portion 33 extends forward along the first load transmission path P1 to the upper and rear edge of the constriction portion 45. For this reason, above the constriction portion 45, the front side flange portion 33 is not formed.

[0093] Next, during a side collision, as described above, when a tensile load acting outward in the vehicle width direction is input to the rear bracket 30L of the present embodiment, the behavior of the rear bracket 30L when it breaks will be described with reference to FIG. 7. FIG. 7 is a perspective view showing, corresponding to FIG. 3, the result of a simulation analysis of the behavior of the rear bracket 30L of the present embodiment during a side collision. FIG. 7(a) shows the initial stage of the side collision, FIG. 7(b) shows the middle stage of the side collision, and FIG. 7(c) shows the late stage of the side collision. Note that FIGS. 7(a), 7(b), and 7(c) show the distribution of the bending stress (moment load) of each part of the rear bracket 30L during a side collision based on the shading by dots. The darker the dots, the higher the bending stress.

[0094] First, during a side collision, a tensile load acting outward in the vehicle width direction is input from the vehicle body 2 to the vehicle body fastening portion B34 of the rear bracket 30L. In other words, as shown in FIG. 6, a load F1 that is pulled inward in the vehicle width direction is input to the first battery fastening portion B42 from the first battery unit 20L, and a load F2 that is pulled inward in the vehicle width direction is input to the second battery fastening portion B43 from the first battery unit 20L.

[0095] Specifically, the load input from the vehicle body fastening portion B34 to the rear bracket 30L is transmitted to the first battery fastening portion B42 along the first load transmission path P1 and is also transmitted to the second battery fastening portion B43 along the second load transmission path P2.

[0096] Here, in the present embodiment, as described above, the longitudinal length L1' (also referred to as "front moment length L1'") between the vehicle body fastening portion B34 and the first battery fastening portion B42 is set to be longer than the longitudinal length L2' (also referred to as "rear moment length L2'") between the vehicle body fastening portion B34 and the second battery fastening portion B43.

[0097] Therefore, at the initial stage of the side collision, when a tensile load acting outward in the vehicle width direction is input from the vehicle body 2 to the vehicle body fastening portion B34 of the rear bracket 30L, a larger moment acts on the first battery fastening portion B42 than on the second battery fastening portion B43. As a result, at the initial stage of a side collision, as shown in FIG. 7(a), stress (moment load) can be concentrated in the vicinity of the first battery fastening portion B42 rather than in the vicinity of the second battery fastening portion B43.

[0098] Here, due to the tensile load acting on the rear bracket 30L during a side collision, stress is concentrated in the vicinity of each vehicle body fastening portion B34 side at the first battery fastening portion B42 and the second battery fastening portion B43. Therefore, as shown in FIG. 4, the rear bracket 30L can be broken along the breaking line CL that linearly connects them.

[0099] And in the present embodiment, by setting the second battery fastening portion B43 to be positioned below the first battery fastening portion B42, the breaking line CL can be set to be linear and extend in the front-upward and rear-downward direction as shown in FIG. 4.

[0100] On the other hand, as shown in FIG. 4, if there is a fastening portion B' at a predetermined position between the vehicle body fastening portion B34 and the second battery fastening portion B43, at the initial stage of a side collision, the stress that should be actively transmitted from the vehicle body 2 side (the vehicle body fastening portion B34 side) to the first battery fastening portion B42 rather than the second battery fastening portion B43 will also be dispersed to the fastening portion B' other than the first battery fastening portion B42 and the second battery fastening portion B43. Then, the stress that should be originally transmitted to the first battery fastening portion B42 becomes smaller, and there is a possibility that the rear bracket 30L cannot be detached from the first battery unit 20L at a desired timing.

[0101] Therefore, in the present embodiment, as described above, after setting the breaking line CL to be linear and extend in the front-upward and rear-downward direction, between the vehicle body fastening portion B34 and the second battery fastening portion B43, by adopting a configuration in which no other fastening portions such as the fastening portion B' are provided on the vehicle body fastening portion B34 side rather than the breaking line CL (see FIG. 4), stress can be concentrated on the first battery fastening portion B42 at the initial stage of a side collision.

[0102] Furthermore, as shown in FIGS. 3 and 4, in the vicinity of the vehicle body fastening portion B34 of the first battery fastening portion B42, as described above, there is a constricted portion 45. Therefore, among the vicinity of the first battery fastening portion B42, stress can be concentrated at the constricted portion 45 (refer to the region corresponding to the constricted portion 45 marked with dots in FIG. 7(a)).

[0103] Therefore, in the middle stage of a side collision, as shown in FIG. 7(b), the constricted portion 45 where stress concentration occurs, as described above, in the vicinity of the first battery fastening portion B42 breaks. As a result, since stress is concentrated in the vicinity of the second battery fastening portion B43, in the late stage of the side collision, as shown in FIG. 7(c), the vicinity of the second battery fastening portion B43 breaks.

[0104] In short, the rear bracket 30L of the present embodiment is configured to reliably break both the vicinity of the first battery fastening portion B42 and the vicinity of the second battery fastening portion B43 by breaking them step by step during a side collision.

[0105] As shown in FIGS. 1 and 2, the lower structure of the vehicle 1 of the present embodiment described above includes a first battery unit 20L (battery unit) provided below the floor panel 4 constituting the vehicle body floor, a skeleton member described later that extends in the front-rear direction outside the first battery unit 20L in the vehicle width direction, a high-voltage cable 14 that extends forward from the front portion of the first battery unit 20L, and a rear bracket 30L as a fixing member that fixes the rear portion of the first battery unit 20L to the skeleton member.

[0106] Furthermore, as shown in FIGS. 1 and 2, the lower structure of the vehicle 1 of the present embodiment includes a side sill 9, and a floor frame 10 and a rear side frame 11 that extend in the front-rear direction adjacent to the side sill 9 on the inner side in the vehicle width direction. The floor frame 10 is provided in front of the rear side frame 11, the rear end of the floor frame 10 and the front portion 11f of the rear side frame 11 are joined to each other, and the rear portion of the first battery unit 20L is fixed to the front portion 11f of the rear side frame 11 as a skeleton member via the rear bracket 30L.

[0107] Further, the lower structure of the vehicle 1 according to the present embodiment is characterized in that when a collision load in the vehicle width direction is input to a position in front of the center of gravity position of the first battery unit 20L, the rear bracket 30L is configured to be breakable.

[0108] According to the above configuration, during a side collision, the rotational behavior of the first battery unit 20L can be suppressed, so that excessive tension is not applied to the high-voltage cable 14 extending forward from the front portion of the first battery unit 20L due to the rotational behavior.

[0109] Specifically, as shown in FIG. 8 from the normal state shown in FIG. 1, when a collision object 80 such as a pole collides with the vehicle body 2 from the outside in the vehicle width direction (the left side of the vehicle body 2 in this example) in front of the vehicle 1 with respect to the center of gravity position of the first battery unit 20L, the side sill 9 deforms in a V shape in a plan view of the vehicle.

[0110] At this time, since the front portion 11f of the rear side frame 11 located behind the collision position of the collision object 80 tends to displace inward in the vehicle width direction, a tensile load from the side of the rear side frame 11 (vehicle body 2) to the outside in the vehicle width direction is input to the rear bracket 30L fixed to the front portion 11f of the rear side frame 11.

[0111] Here, the rear bracket 300 provided in the lower structure 100 of a conventional vehicle (comparative example) as shown in FIG. 9 is robustly formed with priority given to durability (rigidity) against vibration input from the first battery unit 20L during normal driving. For this reason, in the conventional vehicle lower structure 100, during a side collision, as described above, even when a tensile load from the vehicle body 2 side to the outside in the vehicle width direction is input, the first battery unit 20L and the front portion 11f of the rear side frame 11 are maintained in a state of being fixed to each other via the rear bracket 300 as shown in FIG. 10.

[0112] Then, during a side collision, the rear part of the first battery unit 20L tends to be displaced outward in the vehicle width direction following the deformation of the front part 11f of the rear side frame 11 that inclines inward in the vehicle width direction as described above.

[0113] That is, as shown in FIG. 10, when the collision object 80 collides inward in the vehicle width direction, the front part of the first battery unit 20L is pushed inward in the vehicle width direction, so that the tunnel part 7 is compressed and deformed in the vehicle width direction, and the rear part is pulled outward in the vehicle width direction by the front part 11f of the rear side frame 11 via the rear bracket 30L (see arrow D1 in FIG. 10), and shows a behavior of rotating counterclockwise in a bottom view (see arrow D2 in FIG. 10). In that case, there is a concern that a tensile load is applied to the high-voltage cable 14 extending forward from the front part of the first battery unit 20L along with the rotational behavior of the first battery unit 20L.

[0114] On the other hand, as shown in FIG. 8, the lower structure of the vehicle 1 of the present embodiment is configured such that the rear bracket 30L breaks due to an input of a tensile load from the vehicle body 2 side outward in the vehicle width direction during a side collision from the left side of the vehicle 1. For this reason, the rear part of the first battery unit 20L can be separated from the front part 11f (vehicle body 2) of the rear side frame 11 (see FIG. 8).

[0115] Therefore, during a side collision, the rear part of the first battery unit 20L is not pulled outward in the vehicle width direction by the side sill 9 or the like via the rear bracket 30L, and does not follow the deformation such as inclining inward in the vehicle width direction in the rear part of the side sill 9 or the like.

[0116] Therefore, during a side collision, it is possible to suppress the counterclockwise rotational behavior of the first battery unit 20L in which the front part is displaced more inward in the vehicle width direction than the rear part, and it is possible to suppress the application of a tensile load to the high-voltage cable 14 extending forward from the front part of the first battery unit 20L along with the rotational behavior.

[0117] Subsequently, the high-voltage cable 14 extending forward does not need to be formed to be excessively long with a surplus length relative to the actual length in anticipation of a tensile load being applied during a side impact. Therefore, an increase in the electrical resistance of the high-voltage cable 14 can be suppressed.

[0118] As shown in FIGS. 3 and 4, as an embodiment of the present invention, the rear bracket 30L has a vehicle body fastening portion B34, first and second battery fastening portions B42 and B43 that are located below the vehicle body fastening portion B34 and spaced apart in the front-rear direction, and a hole portion 41h formed between the first battery fastening portion B42 and the second battery fastening portion B43.

[0119] According to the above configuration, the load transmission paths P1 and P2 (see FIG. 4) transmitted from the vehicle body fastening portion B34 to the first battery unit 20L side can be separated to each side with the hole portion 41h provided between the first battery fastening portion B42 and the second battery fastening portion B43 therebetween. For this reason, during a side impact, the load input from the vehicle body 2 to the rear bracket 30L via the vehicle body fastening portion B34 is not dispersed between the first battery fastening portion B42 and the second battery fastening portion B43, and can be concentrated in the vicinity of these battery fastening portions B42 and B43.

[0120] Also, since the hole portion 41h contributes to a decrease in the strength in the vicinity of the first and second battery fastening portions B42 and B43, during a side impact, the portion between the first battery fastening portion B42 and the second battery fastening portion B43 is stretched, so that breakage in the vicinity of the first and second battery fastening portions B42 and B43 is not hindered.

[0121] Therefore, during a side impact, the vicinity of the first battery fastening portion B42 and the vicinity of the second battery fastening portion B43 can be reliably broken.

[0122] As shown in FIG. 4, as an embodiment of the present invention, the first battery fastening portion B42 is located forward of the second battery fastening portion B43, and the longitudinal length L1' in the front-rear direction between the vehicle body fastening portion B34 and the first battery fastening portion B42 is longer than the longitudinal length L2' in the front-rear direction between the vehicle body fastening portion B34 and the second battery fastening portion B43. That is, in the present embodiment, the front moment length L1' is set to be longer than the rear moment length L2'.

[0123] By the way, during a side collision, since the rear bracket 30L is pulled outward in the vehicle width direction by the vehicle body 2, a tensile load F1 acting inward in the vehicle width direction acts on the first battery fastening portion B42, and a tensile load F2 acting inward in the vehicle width direction acts on the second battery fastening portion B43 (see FIG. 6).

[0124] Therefore, according to the above configuration, during a side collision, the moment load can be concentrated near the first battery fastening portion B42 rather than near the second battery fastening portion B43. Thus, the vicinity of the first battery fastening portion B42 and the vicinity of the second battery fastening portion B43 can be broken step by step in this order. Therefore, both the vicinity of the first battery fastening portion B42 and the vicinity of the second battery fastening portion B43 can be surely broken during a side collision.

[0125] As shown in FIGS. 3 and 4, as an embodiment of the present invention, the second battery fastening portion B43 is configured to be located below the first battery fastening portion B42.

[0126] According to the above configuration, as shown in FIG. 4, during a side collision, a desired break line CL of the rear bracket 30L due to the tensile load acting on the rear bracket 30L can be set as a straight line connecting the vicinity of each vehicle body fastening portion B34 side of the first battery fastening portion B42 and the second battery fastening portion B43 in the front-up and rear-down direction.

[0127] That is, as described above, since the second battery fastening portion B43 is located below the first battery fastening portion B42, the rear bracket 30L is configured not to be provided with a fastening portion B' between the vehicle body fastening portion B34 and the second battery fastening portion B43, that is, at a position on the vehicle body fastening portion B34 side rather than the break line CL (see FIG. 4). During a side collision, the stress is not dispersed to the fastening portion B', and the stress can be concentrated on the first battery fastening portion B42.

[0128] As shown in FIGS. 3 to 5, as an embodiment of the present invention, in the vicinity of the vehicle body fastening portion B34 side of the first battery fastening portion B42, there is a constriction portion 45 as a strength reduction portion formed with the smallest path width among the first load transmission paths P1 (load transmission paths) (see FIG. 4) that connect the vehicle body fastening portion B34 and the first battery fastening portion B42 in the shortest distance.

[0129] According to the above configuration, at the time of a side collision, the vicinity of the first battery fastening portion B42 can be surely and easily broken, and the breaking portion can be easily controlled.

[0130] As shown in FIGS. 3 to 5, as an embodiment of the present invention, the rear bracket 30L is provided with a front flange portion 33 (flange portion) bent with respect to the first load transmission path P1 along the upper edge (at least one edge portion) in the path width direction of the first load transmission path P1 (the direction orthogonal to the first load transmission path P1 in a side view), and the front lower end 33a (the end portion on the first battery fastening portion B42 side) of the front flange portion 33 is positioned in the vicinity of the constriction portion 45.

[0131] According to the above configuration, in the first load transmission path P1, a rigidity difference is created between the vicinity of the first battery fastening portion B42 and other portions, so that the vicinity of the first battery fastening portion B42 can be surely broken at the time of a side collision.

[0132] In addition, the durability (rigidity) against vibration input from the first battery unit 20L during normal running can be enhanced. Therefore, it is possible to achieve both reliable breakage of the vicinity of the first battery fastening portion B42 at the time of a side collision and durability against vibration input from the first battery unit 20L during normal running.

[0133] The present invention is not limited to the configuration of the above-described embodiments and can be formed in various embodiments. For example, if the skeletal member of the present invention is a skeletal member capable of attaching the rear part of the battery unit 20 via the rear bracket 30L, it is not limited to the rear side frame 11 as in the above-described embodiment, and may be, for example, at least one of the side sill 9 and the floor frame 10.

[0134] In addition, the strength reduction part of the present invention is not limited to being formed as the constricted part 45 as in the above-described embodiment, and a configuration may be adopted in which the thinnest part in the first load transmission path P1, a part provided with a hole (through hole or non-through hole), or a combination of at least two of these is formed.

[0135] In the above-described embodiment, the inverter 13 as a high-voltage device is provided in the first battery unit 20L on the left side of the vehicle 1, but it is not limited thereto, and it may be provided in the second battery unit 20R on the right side of the vehicle 1. In that case, the fixing member (rear bracket 30L) of the present invention can be provided on the right side of the vehicle.

[0136] In addition, the present invention is not limited to being applied to a plug-in hybrid vehicle (PHEV) like the vehicle 1 of the present embodiment as long as it is a vehicle equipped with a motor and an engine, and may be applied to other vehicles such as a hybrid vehicle (HV) or a range-extended electric vehicle (REEV) with a range extender function, for example.

Explanation of Reference Numerals

[0137] 1... Vehicle 4... Floor panel 9... Side sill 10... Floor frame 10r... Rear part of the floor frame 11... Rear side frame (skeletal member) 11f... Front part of the rear side frame 14... High-voltage cable 20L... First battery unit (battery unit) 23... Front flange part (flange part) 30L… Rear Bracket (Fixing Member) 33a… Front Lower End (End on the First Battery Fastening Portion Side) 45… Constriction Portion (Strength Reduction Portion) B34… Vehicle Body Fastening Portion B42… First Battery Fastening Portion B43… Second Battery Fastening Portion 41h… Hole Portion L1’… Front - Rear Direction Length between Vehicle Body Fastening Portion and First Battery Fastening Portion L2’… Front - Rear Direction Length between Vehicle Body Fastening Portion and Second Battery Fastening Portion P1… First Load Transmission Path (Load Transmission Path Connecting Vehicle Body Fastening Portion and First Battery Fastening Portion with the Shortest Distance)

Claims

1. A battery unit provided below a floor panel constituting a vehicle body floor, A skeletal member extending in the longitudinal direction on the outside in the vehicle width direction from the battery unit, A high-voltage cable extending forward from the front portion of the battery unit, And a fixing member for fixing a side surface on the rear portion and the outside in the vehicle width direction of the battery unit to the skeletal member, The fixing member is configured to be breakable when a collision load in the inward vehicle width direction is input at a position forward of the center of gravity position of the battery unit. The lower structure of a vehicle.

2. A battery unit provided below a floor panel constituting a vehicle body floor, A skeletal member extending in the longitudinal direction on the outside in the vehicle width direction from the battery unit, A high-voltage cable extending forward from the front portion of the battery unit, And a fixing member for fixing the rear portion of the battery unit to the skeletal member, The fixing member is configured to be breakable when a collision load in the inward vehicle width direction is input at a position forward of the center of gravity position of the battery unit, The fixing member has a vehicle body fastening portion, first and second battery fastening portions spaced apart in the front-rear direction, and a hole portion formed between the first battery fastening portion and the second battery fastening portion, The first battery fastening portion is located forward of the second battery fastening portion, The longitudinal length in the front-rear direction between the vehicle body fastening portion and the first battery fastening portion is longer than the longitudinal length in the front-rear direction between the vehicle body fastening portion and the second battery fastening portion. The lower structure of a vehicle.

3. The skeletal member is a side sill extending in the longitudinal direction on the outside in the vehicle width direction from the floor panel. The lower structure of a vehicle according to Claim 2.

4. A side sill extending in the longitudinal direction on the outside in the vehicle width direction from the floor panel, And a floor frame and a rear side frame extending in the longitudinal direction adjacent to the side sill on the inside in the vehicle width direction, The floor frame is provided forward of the rear side frame, and the rear portion of the floor frame and the front portion of the rear side frame are joined to each other, The skeletal member is at least one of the floor frame and the rear side frame. The lower structure of a vehicle according to Claim 2.

5. The second battery fastening portion is located below the first battery fastening portion. The lower structure of a vehicle according to Claim 2.

6. having a strength reduction portion near the vehicle body fastening portion side of the first battery fastening portion The underbody structure of the vehicle according to claim 2.

7. The strength reduction portion is a portion where the path width is the smallest or / and the wall thickness is the thinnest among the load transfer paths that connect the vehicle body fastening portion and the first battery fastening portion in the shortest way. The underbody structure of the vehicle according to claim 6.

8. The fixing member is provided with a flange portion that is bent with respect to the load transfer path along at least one edge in the path width direction of the load transfer path. Near the strength reduction portion, the end portion of the flange portion on the first battery fastening portion side is located. The underbody structure of the vehicle according to claim 7.

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