JP7232422B2 - Lower body structure of electric vehicle - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lower body structure of an electric vehicle having a battery unit between a kick-up panel and a first vehicle component arranged below the rear panel.

Conventionally, in electric vehicles such as hybrid vehicles and electric vehicles, the battery that is the power source of the electric motor (for example, motor generator or motor) that drives the wheels has a large capacity, so the space below the vehicle body floor is used for the battery unit. are arranged as follows.
Generally, a battery unit is composed of a plurality of battery modules each made up of an assembly of battery cells such as lithium-ion cells, an upper cover and a lower cover for housing the plurality of battery modules, and supporting members for supporting them on the vehicle body. there is

The battery pack of Patent Document 1 has a casing formed to match the uneven shape of the floor panel. In this casing, three rows of battery modules are arranged in the front-rear direction and six rows in the left-right direction. An upper battery module is arranged above the lower battery module below and below the rear seat.
Further, the front structure of an automobile in Patent Document 2 includes a pair of left and right battery side members extending in the front-rear direction, an intermediate member extending in the front-rear direction between the pair of battery side members, and a pair of front-rear members extending in the left-right direction. A battery case is provided with a cross member and a pair of front and rear intermediate cross members extending laterally between the pair of cross members. The battery case is arranged below the floor panel and below the rear panel. An upper battery module is arranged above the lower battery module in the corresponding area.

The floor panel of a vehicle consists of a front panel and a rear panel connected to the rear of the vehicle via a kick-up panel that rises upward from the front panel. Various vehicle parts such as the rear suspension are arranged below the rear panel. It is
The torsion beam type suspension has a pair of left and right trailing arms whose front ends are pivotally supported by the vehicle body and whose rear ends rotatably support the wheels. and a torsion beam extending in the vehicle width direction.
This torsion beam type suspension has a structure in which a torsion beam consisting of an open cross-section member having a substantially U-shaped cross section with one side half and the other side half extending in the length direction functions as a torsion bar and a spring. Since it is simple, has a small number of parts, and is advantageous in terms of cost and space, it is widely used as a rear suspension for FF vehicles.

JP 2016-178050 A JP 2018-165073 A

In order to extend the cruising range of the vehicle, it is desirable to use the space below the rear panel as well as the space below the front panel to arrange the battery unit.
In other words, since the space below the rear panel has a high ground clearance, a plurality of battery modules can be stacked vertically in multiple stages as in Patent Documents 1 and 2, and a large battery capacity can be secured. .
However, when arranging a plurality of stacked battery modules in the lower space of the rear panel, there is concern about interference between the battery unit and other vehicle components.

As described above, many vehicle parts such as the rear suspension, fuel tank, silencer, etc. are provided below the rear panel, and these parts are arranged close to each other.
Therefore, when the support bracket of the upper battery module is arranged rearward of the rear end of the lower battery module, the rear end of the battery unit projects rearward as a whole, and other vehicles arranged below the rear panel It may be necessary to shift the part backwards.
In particular, in a vehicle equipped with a torsion beam suspension, the torsion beam arranged behind the kick-up panel extends over the entire width of the vehicle, increasing the risk of interference.

SUMMARY OF THE INVENTION An object of the present invention is to provide a lower vehicle body structure for an electric vehicle, etc., in which a battery module can be stacked behind a kick-up panel while avoiding interference with vehicle parts.

According to claim 1, there is provided a lower vehicle body structure for an electric vehicle, comprising: a floor panel having a front panel; a rear panel extending rearward in the longitudinal direction of the vehicle body via a kick-up panel rising upward from the front panel; and a battery unit disposed between the kick-up panel and the first vehicle component, wherein the battery unit is attached to a bottom plate member of the battery unit. The battery module has a supported first battery module and a second battery module arranged above the first battery module via a support mechanism, wherein the rear end of the first battery module is connected to the second battery module. The rear end of the support mechanism is arranged forward of the rear end of the second battery module, and supported below the rear end of the second battery module and behind the rear end of the first battery module.

In this lower vehicle body structure for an electric vehicle, the battery unit includes a first battery module supported by a bottom plate member of the battery unit, and a second battery module disposed above the first battery module via a support mechanism. , a large number of battery modules can be mounted using the rear space of the kick-up panel, which has a high ground clearance, and the cruising distance can be ensured.
The rear end portion of the first battery module is disposed forward of the rear end portion of the second battery module, and the rear end portion of the support mechanism is located below the rear end portion of the second battery module and the first battery module. Since the rear end portion of the second battery module is supported behind the rear end portion, an empty area can be formed behind the rear end portion of the first battery module without retracting the second battery module. It can be supported in the empty area of the bottom plate member located forward of the rear end of the module.

The invention of claim 2 is characterized in that, in the invention of claim 1, the first vehicle component is a torsion beam of a torsion beam suspension.
According to this configuration, the first and second battery modules are arranged between the kick-up panel and the torsion beam type suspension while avoiding interference with the torsion beam extending over the entire width of the vehicle. can be done.

According to a third aspect of the invention, there is provided a mounting bracket for fixing the rear portion of the battery unit to the vehicle body, and the mounting bracket is disposed between the battery unit and the torsion beam. It is characterized by
According to this configuration, the forward movement of the torsion beam can be suppressed by the pair of mounting brackets in the event of a vehicle rear-end collision while ensuring the supporting strength of the battery unit, thereby avoiding direct interference between the torsion beam and the battery unit. be able to.

The invention of claim 4 is the invention of any one of claims 1 to 3, wherein the second battery module is configured to the same specifications as the first battery module, and the front region of the front end portion of the second battery module The feature is that the harness is routed in the
According to this configuration, it is possible to secure a wiring space for the harness using the front region of the front end portion of the second battery module.

The invention of claim 5 is the invention of any one of claims 1 to 4, wherein the battery unit includes a battery frame that supports the bottom plate member, and the battery frame includes a pair of left and right battery frames extending in the longitudinal direction of the vehicle body. and a pair of front and rear second frames that extend in the vehicle width direction and connect the pair of first frames, and the second frame on the rear side is the rear second frame. A sloping portion extending forward and downward from the front end of the lower wall portion and on which the bottom plate member can be placed is formed. It is characterized by
According to this configuration, the support portion at the rear end portion of the support mechanism can be attached regardless of the inclined portion on which the bottom plate member can be placed.

The invention according to claim 6 is the invention according to claim 5, wherein the bottom plate member has an inclined wall capable of surface contact with the inclined part and a vertical wall rising from the upper end of the inclined wall, The upper end portion is fixed to the vertical wall of the bottom plate member.
According to this configuration, it is possible to increase the rigidity of the rear second frame using the supporting portion.

The invention of claim 7 is the invention of claim 5 or 6, further comprising a second vehicle part disposed below the rear panel, and fixing the second vehicle part to the lower wall portion of the rear second frame. It is characterized by having a bolt hole for.
According to this configuration, the second vehicle component can be mounted on the vehicle body while avoiding interference between the second vehicle component fixing bolt and the obstacle.

The invention according to claim 8 is the invention according to any one of claims 5 to 7, wherein the rear second frame comprises an outer member and an inner member that cooperates with the outer member to form a closed cross section. The outer member comprises the lower wall portion, an outer inclined portion extending forward and downward from the front end of the lower wall portion, an outer vertical wall portion extending upward from the rear end of the lower wall portion, and the outer vertical wall portion. and an outer flange portion formed on the upper end side portion of the wall portion, the inner member extending downward from the upper wall portion spaced apart from and facing the lower wall portion and from the front end of the upper wall portion. an inner vertical wall portion spaced apart from and opposed to the outer vertical wall portion, an inner inclined portion extending forward and downward from a lower end of the inner vertical wall portion and superimposed on the outer inclined portion, and the upper wall portion; and an inner flange portion extending upward from a rear end thereof, and the front end portion of the outer inclined portion extends further forward than the front end portion of the inner inclined portion.
According to this configuration, the bottom plate member can be protected by utilizing the inclined portion of the rear second frame while ensuring the rigidity of the battery frame.

According to a ninth aspect of the invention, in the eighth aspect of the invention, after the bottom plate member to which the support portion is attached is attached to the inner member, the outer flange portion and the inner flange portion are joined together and the It is characterized in that the outer inclined portion and the inner inclined portion are joined together.
According to this configuration, it is possible to ensure workability in assembling the rear second frame without affecting the support rigidity of the second battery module.

According to the lower vehicle body structure of the electric vehicle of the present invention, the battery modules can be arranged compactly while ensuring the cruising distance of the vehicle.

4 is a bottom view of the lower vehicle body of the electric vehicle according to the first embodiment; FIG. It is the perspective view seen from the rear lower side. 3 is an exploded perspective view of the battery unit; FIG. FIG. 4 is a rear plan view of the battery unit with an upper cover member and battery modules omitted; FIG. 2 is a perspective view of a battery unit with an upper cover member and battery modules omitted; FIG. 6 is a vertical cross-sectional view of a main part of FIG. 5; FIG. 4 is a perspective view of the support mechanism seen obliquely from the front; FIG. 4 is a perspective view of the support mechanism as seen obliquely from behind; FIG. 5 is a cross-sectional view taken along line IX-IX of FIG. 4; FIG. 5 is a cross-sectional view taken along line XX of FIG. 4; 5 is a cross-sectional view taken along line XI-XI of FIG. 4; FIG. 5 is a cross-sectional view taken along line XII-XII of FIG. 4; FIG.

EMBODIMENT OF THE INVENTION Hereinafter, the form for implementing this invention is demonstrated based on drawing. The following description of preferred embodiments is merely exemplary in nature and is not intended to limit the invention, its applications or uses.

Embodiment 1 of the present invention will be described below with reference to FIGS. 1 to 15. FIG.
A vehicle V according to the first embodiment is a hybrid vehicle that uses an internal combustion engine (not shown) such as a gasoline engine or a diesel engine and an electric motor (motor generator) (not shown) for driving the vehicle as drive sources.

As shown in FIGS. 1 and 2, a vehicle V includes a pair of left and right side sills 1 extending forward and backward, a floor panel 2, a pair of left and right floor frames 3 extending forward and backward, and a pair of left and right rear sides extending forward and backward. A frame 4, a rear suspension 20, a battery unit 30, and the like are provided.
Hereinafter, in the drawings, the direction of arrow F is defined as the front in the longitudinal direction of the vehicle body, the direction of arrow L is defined as the left in the vehicle width direction, and the direction of arrow U is defined as the upper direction in the vertical direction of the vehicle. Further, the vehicle V has a substantially bilaterally symmetrical structure.

First, a pair of side sills 1 will be described.
The side sill 1 includes an outer panel having a substantially hat-shaped cross section forming a vehicle width direction outer wall portion, and an inner panel having a substantially hat-shaped cross section forming a vehicle width direction inner wall portion. It forms an elongated substantially rectangular closed cross section. A vertically extending hinge pillar is connected to the front end portion of the side sill 1, and a vertically extending rear pillar is connected to the rear end portion thereof. The vehicle V has a so-called double door structure in which the front door opens and closes around the hinge of a hinge pillar formed at the front end, and the rear door opens and closes around the hinge formed at the rear end. Pillars are omitted.

Next, the floor panel 2 will be explained.
The floor panel 2 is formed to span between a pair of side sills 1. - 特許庁
As shown in FIGS. 1 and 9 to 12, the floor panel 2 includes a front panel 2a on which a seat for a front seat passenger (not shown) is mounted, and a rear end of the front panel 2a upwardly sloping rearward. and a rear panel 2b on which a rear passenger seat (not shown) is mounted. The left and right end portions of the front panel 2a are joined to the inner wall portions of the pair of side sills 1 to form the floor of the front passenger compartment, and the left and right end portions of the rear panel 2b are joined to the pair of rear side frames 4, respectively. form the floor of the rear passenger compartment.

As shown in FIGS. 9 to 12, at the apex (upper end) of the kick-up panel 2c, a first cloth is formed which cooperates with the lower surface of the kick-up panel 2c to form a closed cross-section having a substantially rectangular cross-section extending left and right. A member 5 is arranged. Both ends of the first cross member 5 connect front portions of the pair of rear side frames 4 . Behind the first cross member 5, second and third cross members 6 and 7 having a substantially hat-shaped cross section extending left and right are arranged. The second cross member 6 cooperates with the lower surface of the rear panel 2b to form a closed cross section with a substantially rectangular cross section extending left and right, and the third cross member 7 cooperates with the upper surface of the rear panel 2b to form a closed cross section extending horizontally. It forms a substantially rectangular closed cross section. The second and third cross members 6 and 7 cooperate to form a closed cross-section structure extending left and right while sandwiching the rear panel 2b as a joint member. are concatenated.

Next, the floor frame 3 and the pair of rear side frames 4 will be explained.
As shown in FIG. 1, the pair of floor frames 3 are each formed to have a substantially hat-shaped cross section, and the distance between the pair of floor frames 3 increases toward the rear. Therefore, the distance between the side sill 1 and the adjacent floor frame 3 becomes closer toward the rear. The floor frame 3 cooperates with the lower surface of the front panel 2a to form a closed cross section with a substantially rectangular cross section extending forward and backward.

As shown in FIGS. 1 and 2, the pair of rear side frames 4 extend rearward from the rear ends of the pair of floor frames 3 along the kick-up panel 2c and the rear panel 2b, respectively.
The rear side frame 4 includes an outer panel that forms a vehicle width direction outer wall portion and an inner panel that forms a vehicle width direction inner wall portion. are doing. Rear end portions of the pair of rear side frames 4 are connected by a fourth cross member 8 extending left and right.

As shown in FIGS. 1, 2, and 9, a pair of left and right tank support members 10 extending in the front-rear direction are connected to the middle portion of the fourth cross member 8, respectively. The pair of tank support members 10 are each formed to have a closed cross-section gently curving downward, and are configured to support the left and right end portions of the fuel tank 9 from below, respectively. The tank support member 10 has a front end portion fastened and fixed to the lower end portion of a battery frame 40 (outer member 46) described later via bolts b1, and a rear end portion fastened to the lower end portion of the fourth cross member 8 via a fastening member. fastening is fixed.

Next, the rear suspension 20 will be explained.
The suspension 20 is arranged behind the kick-up panel 2c and below the rear panel 2b. As shown in FIGS. 1 and 2, the suspension 20 includes a pair of left and right trailing arms 21 that rotatably support wheels (not shown) at the rear end, and a pair of trailing arms 21 at both ends in the vehicle width direction. It is a torsion beam type suspension provided with torsion beams 22 extending to the left and right, which are connected to arms 21 respectively.

The pair of trailing arms 21 are arranged in a substantially V shape in a plan view so that the distance in the vehicle width direction increases toward the rear, and the front end portion is composed of a pivot extending in the vehicle width direction and a rubber bush. They are pivotally supported by the lower front ends of the pair of rear side frames 4 via joints 23, respectively. A carrier is provided at the rear end of the trailing arm 21, and this carrier rotatably supports the wheel. A shock absorber (not shown) is provided in the vicinity of the carrier for connecting the vehicle body side and the rear end of the trailing arm 21 so as to absorb impact.

A pair of right and left torsion beams 22 and the trailing arm 21 are welded so as to bridge the vehicle width direction inner portion extending from the middle portion to the rear end portion of the trailing arm 21 and the vehicle width direction outer portion. Gussets 24 (spring support members) are provided. Between these gussets 24 and the vehicle body, compression coil springs (not shown) that cooperate with shock absorbers to constitute a vibration absorbing mechanism of the vehicle V are elastically mounted, and the lower ends of the compression coil springs are supported by the gussets 24 . It is

As shown in FIGS. 9 to 12, the torsion beam 22 corresponds to a position between the kick-up panel 2c and the fuel tank 9 and between the tank support member 10 and the second cross member 6 when viewed from the side. are arranged to The torsion beam 22 is formed by compressing a cylindrical pipe member in the lengthwise direction from the direction perpendicular to the axis, so that the torsion beam 22 is formed by one side half and the other side half, and has a cross section with an opening directed downward. It is composed of a V-shaped open cross-section member. When an external force acts on one wheel and the other wheel is displaced in the opposite phase, these external forces are applied to the deflection of the overall shape of the torsion beam 22 and the opening of the open cross section formed by one half and the other half. It is absorbed by closing deformation.

Next, the battery unit 30 will be explained.
As shown in FIGS. 3 and 9 to 12, the battery unit 30 accommodates a high-voltage battery in which a plurality (for example, 16) of first and second battery modules 31 and 32 are connected in series, and is mounted on the floor panel. It is laid out in the lower space of 2. Therefore, the battery unit 30 is configured to ensure vibration resistance and water resistance. The first and second battery modules 31 and 32 that supply electric power to the vehicle drive motor are rectangular parallelepiped battery assemblies in which a plurality of rectangular parallelepiped battery cells C having standard voltages are arranged in layers. The battery cell C is, for example, a lithium ion battery, which is a type of secondary battery.

As shown in FIGS. 3 to 12, the battery unit 30 includes first and second battery modules 31 and 32, a first bottom plate member 33 on which twelve first battery modules 31 are mounted, and this first bottom plate member 33. An upper cover member 34 that cooperates with the member 33 to form a sealed space that accommodates the first and second battery modules 31 and 32, a battery frame 40 that supports the first bottom plate member 33, and four second batteries. A main component is a support mechanism 60 for placing the module 32 above the first battery module 31 on the rear side. The first bottom plate member 33 and the battery frame 40 correspond to a lower cover member.

The first bottom plate member 33 is made of a metal plate material, such as an aluminum alloy plate material, and is shaped like a rectangular bucket. As shown in FIGS. 3 and 6, the first bottom plate member 33 includes a flat bottom wall 33a on which the first battery module 31 can be placed, and a height position extending outward from the outer edge of the bottom wall 33a. A first vertical wall 33c extending vertically upward from the upper end of the inclined wall 33b, and a horizontal wall extending outward from the upper end of the vertical wall 33c. It has an extending lateral wall 33d.

The bottom wall 33a is divided into three areas, a front area, an intermediate area, and a rear area, in order from the front.
Four first battery modules 31 are placed in each area in the left-right direction in a posture in which the longitudinal direction is parallel to the front-rear direction. Four second battery modules 32 are arranged above the four first battery modules 31 in the rear area. The height position of the upper end of the first battery module 31 is arranged so as to be lower than the height position of the front panel 2a, and the first battery module 31 and the second battery module 32 are arranged vertically and horizontally. and the same specifications, including the height dimension, that is, the same shape.

The upper cover member 34 is made of synthetic resin material, for example. The upper cover member 34 is configured such that the height dimension of the portion covering the rear region of the bottom wall 33a is larger than the height dimension of the portion covering the front region and the middle region of the bottom wall 33a. As shown in FIG. 6, the outer edge of the upper cover member 34 is fastened and fixed to the lateral wall 33d of the first bottom plate member 33 by a plurality of fastening members with a sealing gasket interposed therebetween.

The battery frame 40 includes a pair of left and right first frames extending in the front-rear direction and a pair of second front-rear frames extending in the left-right direction. Specifically, as shown in FIG. 3 , the battery frame 40 includes a substantially square-shaped lower frame 41 and a substantially square-shaped battery frame 41 that cooperates with the lower frame 41 to form a substantially rectangular closed cross section. and an upper frame 42, and is formed by a substantially square-shaped closed cross-section structure. Further, the battery frame 40 has cross member members 43 to 45 which cooperate with the upper surface of the bottom wall 33a between the pair of first frames to form a substantially rectangular closed cross section extending left and right. there is The bottom wall 33a has a front area defined by the cross member members 43 and 44, an intermediate area defined by the cross member members 44 and 45, and a rear area corresponding to the cross member member 45 and the rear end portion of the battery frame 40. It is partitioned by the rear second frame.

Here, the rear second frame will be further described.
The rear second frame is composed of an outer member 46 corresponding to the rear end portion of the lower frame 41 and an inner member 47 corresponding to the rear end portion of the upper frame 42 .
As shown in FIG. 6, the outer member 46 includes a lower wall portion 46a orthogonal to the vertical direction, an inclined portion 46b (outer inclined portion) extending frontward and downward from the front end of the lower wall portion 46a, and the lower wall portion 46a. It has a vertical wall portion 46c (outer vertical wall portion) extending vertically upward from the rear end, and a flange portion 46d (outer flange portion) extending upward from the upper end of the vertical wall portion 46c.

The inner member 47 includes an upper wall portion 47a spaced apart from the lower wall portion 46a and opposed to it, and a vertical wall extending vertically downward from the front end of the upper wall portion 47a and spaced apart from the vertical wall portion 46c and opposed to the vertical wall portion 46c. A portion 47b (inner vertical wall portion), an inclined portion 47c (inner inclined portion) extending forward and downward from the lower end of the vertical wall portion 47b, and a flange portion 47d (inner flange portion) extending vertically upward from the rear end of the upper wall portion 47a. part).

As shown in FIGS. 1, 2, and 9, bolt holes communicating between the inside and the outside of the closed cross section are formed in the left and right end portions of the lower wall portion 46a of the outer member 46. The front ends are fastened and fixed using bolts b1. As a result, the ground clearance of the bolt b1 can be made higher than the bottom wall 33a of the first bottom plate member 33, thereby avoiding interference between the bolt b1 and obstacles.

As shown in FIG. 6, the inclined portion 46b and the flange portion 46d of the outer member 46 are welded to the inclined portion 47c and the flange portion 47d of the inner member 47, respectively.
The inclined wall 33b of the first bottom plate member 33 is placed on the inclined portions 46b and 47c.
Since the inclined portion 46b extends further forward than the front end portion of the inclined portion 47c, the rear portion of the inclined wall 33b is supported on the inclined portion 47c in surface contact, and the front portion of the inclined wall 33b is inclined. It is supported in surface contact on the portion 46b. The front end portion of the inclined portion 46b is also in surface contact with the rear portion of the bottom wall 33a. Thereby, interference between the rear end portion of the first bottom plate member 33 and the obstacle is avoided by using the inclined portions 46b and 47c.

The battery frame 40 is attached to the vehicle body using a plurality (eg, thirteen) of brackets 51-54. As shown in FIG. 3 , the lower frame 41 includes a pair of left and right front brackets 51 , four pairs of left and right first side brackets 52 , a pair of left and right second side brackets 53 , and a rear bracket 54 . is provided.

A pair of front brackets 51 are provided so as to protrude forward from the front wall portion of the front second frame, and are fastened and fixed to the lower surface of the front portion of the front panel 2a using bolts b2.
Each first side bracket 52 is provided so as to protrude outward in the vehicle width direction from the vehicle width direction outer wall portion of the first frame, and is attached to the lower wall portion of the floor frame 3 using bolts b3 (see FIG. 5). They are fastened and fixed. A pair of second side brackets 53 are provided at the rear end of the first frame, respectively. As shown in FIGS. 1, 2, and 5, the second side bracket 53 has a vertically extending vertical wall portion fixed to the vehicle width direction outer wall portion of the first frame so that the upper end portion of the vertical wall portion extends toward the vehicle. A lateral wall extending outward in the width direction is fastened and fixed to the lower wall of the floor frame 3 using bolts b4.

The rear bracket 54 is constructed as a single piece press-formed from a sheet metal material, such as a hot-rolled steel plate. The rear bracket 54 has a lower end fastened to a nut n1 (see FIGS. 6 and 11) fixed to the vertical wall portion 46c of the outer member 46 via a bolt b5, and an upper end to the second cross member 6. It is fastened and fixed to a pair of left and right nuts n2 fixed to the lower wall portion via a pair of left and right bolts b6.

Next, the support mechanism 60 for the second battery module 32 will be described.
As shown in FIGS. 4, 5, and 9 to 12, the support mechanism 60 includes a first bottom plate member 33 partitioned by a cross member member 45 and a rear second frame (outer member 46 and inner member 47). It is disposed in the rear region of (bottom wall 33a). The support mechanism 60 has four rear end portions of the first battery modules 31 placed in the rear region of the first bottom plate member 33 in the left-right direction. The second battery module 32 is a support mechanism that supports the second battery module 32 so as to be forward of the rear end portion of the second battery module 32 . The upper end of the second battery module 32 is arranged so as to be higher than the top of the torsion beam 22 .

As shown in FIGS. 4 to 12, the support mechanism 60 is formed by pressing a metal plate material, for example, a steel plate, and has a rectangular second bottom plate member 61 on which the second battery module 32 is mounted. a substantially π-shaped upper front support portion 62 that supports the front end portion of the second bottom plate member 61; a substantially π-shaped upper rear support portion 63 that supports the rear end portion of the second bottom plate member 61; 2 Mainly composed of a pair of substantially T-shaped left and right side support portions 64 that support the left and right ends of the bottom plate member 61, and a pair of left and right lower rear support portions 65 that support the upper rear side support portion 63. element.

The upper front support portion 62 is formed such that an upper wall portion perpendicular to the vertical direction extends left and right, and a pair of legs extend downward from both left and right side portions and are attached to the upper wall portion of the cross member member 45 respectively. It is fastened and fixed via a fastening member. The upper rear support portion 63 is formed such that an upper wall portion perpendicular to the vertical direction extends left and right, and a pair of legs extend downward from both left and right side portions to form a pair of lower rear support portions. 65 are fastened and fixed to holding portions 65a of 65 via respective fastening members.

As shown in FIGS. 4, 5, 7 and 8, the pair of side support portions 64 are formed such that upper wall portions perpendicular to the vertical direction extend forward and backward, and leg portions extend from intermediate portions. They are fastened and fixed to fixed portions 66 extending downward and fixed to the bottom wall 33a via fastening members. The front ends of the pair of side support portions 64 are fastened and fixed to the left and right ends of the upper wall portion of the upper front support portion 62 via fastening members, respectively, and the rear end portions are fastened to the top of the upper rear support portion 63. They are fastened and fixed to the left and right end portions of the wall portion via fastening members, respectively.

As shown in FIGS. 3 and 6 to 12, the pair of lower rear support portions 65 are sandwiched between the rear end portion of the first battery module 31 and the rear end portion of the second battery module 32 in side view. In other words, it is partially supported by the rear region of the first bottom plate member 33 corresponding to the lower rear end portion of the second battery module 32 and the rear portion of the rear end portion of the first battery module 31 . The rear end portion of the battery module includes parts integrally attached to the battery module, such as terminals protruding rearward from the rear wall of the rearmost battery cell C. As shown in FIG. The pair of lower rear support portions 65 and the first bottom plate member 33 cooperate to form a partially open closed cross section with a substantially trapezoidal cross section.

As shown in FIGS. 6 to 12, the pair of lower rear support portions 65 includes a holding portion 65a extending horizontally and perpendicular to the vertical direction, and a plurality of ( For example, two legs 65b are provided.
A flange portion extending vertically upward is formed at the rear end portion of the holding portion 65a, and this flange portion is joined to the front surface of the first vertical wall 33c of the first bottom plate member 33 by welding.
Flanges extending forward are formed at the lower ends of the plurality of leg portions 65b, and these flange portions are welded to the upper surface of the bottom wall 33a positioned forward of the inclined wall 33b.
These leg portions 65b are arranged substantially vertically linearly with the leg portions of the upper rear support portion 63 in a side view. A pair of the lower rear support portion 65 and the upper rear support portion 63 correspond to the rear end portion of the support mechanism 60 .

When assembling the lower cover member of the battery unit 30, first, the cross member members 43 to 45 and the pair of lower rear support portions 65 are joined to the first bottom plate member 33 by welding.
Next, a sub-assembly is formed by assembling the first bottom plate member 33 to the upper frame 42, and the flange portions of the lower frame 41 and the upper frame 42 (sub-assembly) are joined by welding.
In the rear second frame corresponding to the rear end portion of the battery frame 40, the flange portion 46d of the outer member 46 and the flange portion 47d of the inner member 47 are joined by welding, and the inclined portion 46b and the inclined portion 47c are formed on the lower rear side. It is joined by welding at the release portion of the support portion 65 .

The first and second battery modules 31 and 32 are positioned on the support mechanism 60 by a plurality of battery holding plates 67-70.
As shown in FIGS. 5 and 7 to 12, the pair of left and right front lower battery holding plates 67 includes holding wall portions perpendicular to the front-rear direction and cross member members 45 extending forward from the lower ends of the holding wall portions. legs fastened to the upper wall of the housing. As shown in FIGS. 6 to 12, the pair of left and right rear lower battery holding plates 68 includes a holding wall perpendicular to the front-rear direction, and a holding wall extending rearward from the lower end of the holding wall and fastened and fixed to the holding portion 65a. each with curved legs. The holding wall portions of the pair of front lower battery holding plates 67 are respectively fastened to the front wall portions of the two adjacent first battery modules 31, and the holding wall portions of the pair of rear lower battery holding plates 68 are fastened to the adjacent front wall portions. The rear wall portions of the two first battery modules 31 are fastened to each other.

The pair of left and right front upper battery holding plates 69 includes holding wall portions perpendicular to the front-rear direction, and leg portions extending forward from the lower ends of the holding wall portions and fastened and fixed to the upper wall portion of the upper front support portion 62 . They are prepared. The pair of left and right rear upper battery holding plates 70 includes a holding wall portion perpendicular to the front-rear direction, and the lower end of the holding wall portion is connected to the rear wall portion of the upper rear side support portion 63 and the pair of side support portions 64 . Each has a leg that is fixed to the rear end.
The holding wall portions of the pair of front upper battery holding plates 69 are respectively fastened to the front wall portions of the two adjacent second battery modules 32, and the holding wall portions of the pair of rear upper battery holding plates 70 are fastened to the adjacent front wall portions. It is fastened to the rear wall portions of the two second battery modules 32 that match.

As shown in FIGS. 6 and 10, a substantially rectangular parallelepiped empty area S is provided behind the first battery module 31 held by the battery holding plates 67 and 68 . The empty area S is formed below the rear end portion of the second battery module 32 held by the battery holding plates 69 and 70 and behind the rear end portion of the first battery module 31 held by the battery holding plates 67 and 68 . , extending in the vehicle width direction.

As shown in FIGS. 5 and 10 to 12, a collective harness 35 connected to the first battery modules 31 placed on the front and middle regions of the bottom wall 33a passes through the left and right middle portions of the bottom wall 33a. The second battery module 32 is connected to the second battery module 32 by being routed in a substantially straight line toward the support mechanism 60 . The harness 35 is bent rightward along the upper front support portion 62 .
Since the rear end portion of the first battery module 31 is arranged forward of the rear end portion of the second battery module 32, the space above the first battery module 31 and in front of the front end portion of the second battery module 32 is It is used as a wiring space for the harness 35 .

Next, the operation and effects of the lower vehicle body structure will be described.
According to the lower vehicle body structure according to the first embodiment, the battery unit 30 includes the first battery module 31 supported by the first bottom plate member 33 of the battery unit 30, and the support mechanism 60 above the first battery module 31. Since the kick-up panel 2c has a high ground clearance, a large number of battery modules 31 and 32 can be mounted using the rear space of the kick-up panel 2c, which has a high ground clearance. can be done.
The rear end portion of the first battery module 31 is arranged forward of the rear end portion of the second battery module 32 , and the lower rear side support portion 65 corresponding to the rear end portion of the support mechanism 60 is located at the rear end portion of the second battery module 32 . Since the second battery module 32 is supported below the rear end portion and behind the rear end portion of the first battery module 31, the empty area S can be formed behind the rear end portion of the first battery module 31 without retracting the second battery module 32. At least a portion of the lower rear support portion 65 of the support mechanism 60 can be supported in the empty area S of the first bottom plate member 33 located forward of the rear end portion of the second battery module 32 .

Since the first vehicle component is the torsion beam 22 of the suspension 20, the first and second battery modules 31 and 32 are kicked up while avoiding interference with the torsion beam 22 extending over the entire vehicle width direction. It can be arranged between the panel 2 c and the suspension 20 .

A rear bracket 54 is provided for fixing the rear portion of the battery unit 30 to the vehicle body, and the rear bracket 54 is arranged between the battery unit 30 and the torsion beam 22. Therefore, while ensuring the supporting strength of the battery unit 30, In the event of a vehicle rear-end collision, the forward movement of the torsion beam 22 can be suppressed by the pair of rear brackets 54, and direct interference between the torsion beam 22 and the battery unit 30 can be avoided.

Since the second battery module 32 has the same specifications as the first battery module 31 and the harness 35 is routed in the front region of the front end of the second battery module 32, the front region of the front end of the second battery module 32 is used. Therefore, a wiring space for the harness 35 can be secured.

The battery unit 30 includes a battery frame 40 that supports the first bottom plate member 33. The battery frame 40 includes a pair of left and right first frames extending in the front-rear direction, and a front and rear frame connecting the pair of first frames extending in the left-right direction. The second frame on the rear side extends forward downward from the front end of the lower wall portion 46a of the second frame on the rear side and is an inclined portion on which the first bottom plate member 33 can be placed. 46b (47c) are formed, and a lower rear support portion 65 at the rear end portion of the support mechanism 60 is attached to the bottom wall 33a of the first bottom plate member 33 in front of the inclined portion 46b.
Accordingly, the lower rear support portion 65 at the rear end portion of the support mechanism 60 can be attached to the flat portion regardless of the inclined portion 46b on which the first bottom plate member 33 can be placed.

The first bottom plate member 33 has an inclined wall 33b capable of making surface contact with the inclined portion 46b (47c), and a first vertical wall 33c rising from the upper end of the inclined wall 33b. Since 65a is fixed to the first vertical wall 33c of the first bottom plate member 33, the lower rear support portion 65 can be used to increase the rigidity of the rear second frame.

It has a fuel tank 9 as a second vehicle part disposed below the rear panel 2b, and a bolt hole for fixing a tank support member 10 of the fuel tank 9 is formed in the lower wall portion 46a of the rear second frame. Therefore, the fuel tank 9 can be mounted on the vehicle body while avoiding interference between the bolt b1 for fixing the tank support member 10 and an obstacle.

The rear second frame has an outer member 46 and an inner member 47 that cooperates with the outer member 46 to form a closed cross-section. An inclined portion 46b extending forward and downward from the front end, a vertical wall portion 46c extending upward from the rear end of the lower wall portion 46a, and a flange portion 46d formed at the upper end portion of the vertical wall portion 46c. The member 47 includes an upper wall portion 47a that is spaced apart from the lower wall portion 46a and opposed to the lower wall portion 46a, and a vertical wall portion 47b that extends downward from the front end of the upper wall portion 47a and is spaced apart from and opposed to the vertical wall portion 46c. , an inclined portion 47c extending forward and downward from the lower end of the vertical wall portion 47b and overlapped with the inclined portion 46b; and a flange portion 47d extending upward from the rear end of the upper wall portion 47a. However, since it extends further forward than the front end of the inclined portion 47c, the first bottom plate member 33 is protected using the inclined portions 46b and 47c of the rear second frame while ensuring the rigidity of the battery frame 40. be able to.

After the first bottom plate member 33 to which the lower rear support portion 65 is attached is attached to the inner member 47, the flange portion 46d and the flange portion 47d are joined, and the inclined portion 46b and the inclined portion 47c are joined. Therefore, the workability of assembling the rear second frame can be ensured without affecting the support rigidity of the second battery module 32 .

Next, a modified example in which the above embodiment is partially changed will be described.
1) In the above embodiment, an example of a hybrid vehicle provided with an internal combustion engine such as an engine and an electric motor has been described, but it is sufficient that at least a battery unit is provided, and the electric vehicle may be provided with only an electric motor. .

2) In the above embodiment, an example of the battery unit 30 accommodating the first battery module 31 under the front panel 2a and the first and second battery modules 31 and 32 under the rear panel 2b has been described. The battery unit 30 may be arranged between the kick-up panel 2c and the suspension 20, or may be a battery unit 30 in which only vertically stacked battery modules are arranged behind the kick-up panel 2c. .

3) In the above embodiment, the legs of the upper rear support part 63 are supported by the holding parts 65a of the lower rear support part 65. In addition, the first battery module 31 may be supported in the space S behind the rear end portion thereof, and the inner member 47 of the rear second frame may be provided with a support portion to support the legs of the upper rear support portion 63 . is also possible. Also, although an example in which a pair of left and right lower rear support portions 65 are provided has been described, a single lower rear support portion 65 may be provided, or three or more lower rear support portions 65 may be provided. .

4) In addition, without departing from the spirit of the present invention, a person skilled in the art can implement the above-described embodiment in a form in which various modifications are added or in a form in which each embodiment is combined. Any modifications are also included.

2 Floor panel 2a Front panel 2b Rear panel 2c Kick-up panel 9 Fuel tank 20 Rear suspension 22 Torsion beam 30 Battery unit 31 First battery module 32 Second battery module 33 First bottom plate member 33b Inclined wall 33c First vertical wall 35 Assembly harness 40 Battery frame 46 Outer member 46a Lower wall portion 46b Slanted portion 46c Vertical wall portion 46d Flange portion 47 Inner member 47a Upper wall portion 47b Vertical wall portion 47c Slanted portion 47d Flange portion 54 Rear bracket 60 Support mechanism 65 Lower rear support portion S Empty Area V vehicle

Claims (9)

A floor panel having a front panel and a rear panel extending rearward in the longitudinal direction of the vehicle via a kick-up panel rising upward from the front panel, a first vehicle component disposed below the rear panel, and the kick-up panel. and a battery unit disposed between a first vehicle component,
The battery unit has a first battery module supported by a bottom plate member of the battery unit, and a second battery module arranged above the first battery module via a support mechanism,
a rear end portion of the first battery module is disposed forward of a rear end portion of the second battery module;
A lower body structure for an electric vehicle, wherein the rear end of the support mechanism is supported below the rear end of the second battery module and behind the rear end of the first battery module. 2. The lower body structure of an electric vehicle according to claim 1, wherein the first vehicle component is a torsion beam of a torsion beam type suspension. 3. The electric vehicle according to claim 2, further comprising a mounting bracket for fixing the rear portion of the battery unit to the vehicle body, the mounting bracket being disposed between the battery unit and the torsion beam. Lower body structure. The second battery module is configured to the same specifications as the first battery module,
The lower vehicle body structure for an electric vehicle according to any one of claims 1 to 3, wherein a harness is routed in a front region of the front end portion of the second battery module. The battery unit includes a battery frame that supports the bottom plate member,
The battery frame has a pair of left and right first frames extending in the longitudinal direction of the vehicle body, and a pair of front and rear second frames extending in the vehicle width direction and connecting the pair of first frames,
The second frame on the rear side has an inclined portion extending forward and downward from the front end of the lower wall portion of the second frame on the rear side and on which the bottom plate member can be placed,
The lower body structure of an electric vehicle according to any one of claims 1 to 4, wherein the support portion of the rear end portion of the support mechanism is attached to the bottom plate member area forward of the inclined portion. . The bottom plate member has an inclined wall capable of making surface contact with the inclined portion, and a vertical wall rising from an upper end portion of the inclined wall,
6. The lower vehicle body structure for an electric vehicle according to claim 5, wherein the upper end portion of the support portion is fixed to the vertical wall of the bottom plate member. a second vehicle component disposed below the rear panel;
7. The lower vehicle body structure for an electric vehicle according to claim 5, wherein a bolt hole for fixing the second vehicle component is formed in the lower wall portion of the rear second frame. the rear second frame has an outer member and an inner member that cooperates with the outer member to form a closed cross section;
The outer member includes the lower wall portion, an outer inclined portion extending forward and downward from the front end of the lower wall portion, an outer vertical wall portion extending upward from the rear end of the lower wall portion, and the outer vertical wall portion. and an outer flange portion formed on the upper end side portion,
The inner member includes an upper wall portion spaced apart from and opposed to the lower wall portion, and an inner vertical wall portion extending downward from a front end of the upper wall portion and spaced apart from and opposed to the outer vertical wall portion. an inner inclined portion extending forward and downward from the lower end of the inner vertical wall portion and overlapped with the outer inclined portion; and an inner flange portion extending upward from the rear end of the upper wall portion,
The lower vehicle body structure for an electric vehicle according to any one of claims 5 to 7, wherein the front end portion of the outer inclined portion extends further forward than the front end portion of the inner inclined portion. After the bottom plate member to which the support portion is attached is attached to the inner member, the outer flange portion and the inner flange portion are joined, and the outer inclined portion and the inner inclined portion are joined. The lower vehicle body structure for an electric vehicle according to claim 8.

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