JP7340162B2 - Lower body structure of electric vehicle - Google Patents

Description

The present invention relates to a lower body structure of an electric vehicle that includes a battery unit between a kick-up panel and a torsion beam suspension.

Conventionally, in electric vehicles such as hybrid cars and electric cars, the battery that is the power source for the electric motor (for example, a 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. It is arranged as follows.
Usually, a battery unit is composed of a plurality of battery modules made up of a collection of battery cells such as lithium ion, an upper cover and a lower cover that house the plurality of battery modules, and a support member that supports these on the vehicle body. There is.

The electric vehicle of Patent Document 1 has a battery unit disposed below a floor panel and between a pair of left and right side members, and this battery unit has a plurality of battery modules mounted thereon and is arranged in the vehicle width direction. A battery case includes a tray member to which a plurality of girder members are fixed, and a cover member that covers the tray member. It is fixed between the side members.
This allows the girder member, which is part of the tray member, to function as a cross member of the vehicle body, thereby ensuring vehicle body rigidity without lowering the minimum ground clearance.

The floor panel of a vehicle consists of a front panel and a rear panel that extends to the rear of the vehicle through a kick-up panel that stands upward from the front panel. Various vehicle parts such as the rear suspension are arranged below the rear panel. has been done.
The torsion beam suspension has a pair of left and right trailing arms whose front end is pivotally supported by the vehicle body and whose rear end rotatably supports the wheels, and both ends in the vehicle width direction are connected to a pair of left and right trailing arms, respectively. and a torsion beam extending in the vehicle width direction.
In this torsion beam type suspension, a torsion beam consisting of an open cross-section member, such as a generally U-shaped cross section with one half extending in the length direction and the other half, functions as a torsion bar or a spring, and the structure is Because 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 front-wheel drive vehicles.

JP2009-083597A

As in Patent Document 1, in order to expand the cruising distance of the vehicle, it is desirable to arrange the battery unit using the space below the rear panel in addition to the space below the front panel.
In other words, since the space below the rear panel has a high ground clearance, a plurality of battery modules can be stacked vertically, and a large battery capacity can be secured.
However, when the battery unit is disposed in the space below the rear panel, there is a concern that the battery unit may be damaged due to interference between the battery unit and other vehicle components.

As described above, many vehicle parts such as a rear suspension, a fuel tank, and a silencer are provided below the rear panel, and each part is arranged close to each other.
In vehicles equipped with torsion beam suspension, the torsion beam placed behind the kick-up panel extends across the entire width of the vehicle, so in the event of a side collision to the rear of the vehicle, the beam will move inward in the width direction of the vehicle. There is a possibility that the torsion beam will be compressed and bent due to the collision load, and the middle part of the vehicle in the width direction will move forward. If the torsion beam moves forward, there is a possibility that the front end of the intermediate portion of the torsion beam may interfere with the rear end of the battery unit disposed between the kick-up panel and the torsion beam.
In particular, in the case of a battery unit in which a plurality of battery modules are stacked vertically, the surface area (facing area) of the rear end region of the battery unit increases, which further increases the risk of interference with the deformed torsion beam.

An object of the present invention is to provide a lower body structure of an electric vehicle that can avoid interference between the torsion beam and the battery unit in an electric vehicle equipped with a battery unit between a kick-up panel and a torsion beam type suspension. .

The lower body structure of an electric vehicle according to claim 1 includes a floor panel having a front panel and a rear panel that extends rearward in the longitudinal direction of the vehicle body through a kick-up panel that stands upward from the front panel, and a floor panel that is disposed below the rear panel. In the lower body structure of an electric vehicle, the lower body structure includes a torsion beam type suspension, and a battery unit disposed between the kick-up panel and the suspension. a pair of left and right trailing arms that rotatably support wheels at a portion thereof; a torsion beam connected to the pair of trailing arms; and a left and right trailing arm installed between the pair of trailing arms and the torsion beam. It has a pair of spring support members, the rear part of the battery unit is fixed to the vehicle body by a pair of left and right mounting brackets , and the pair of mounting brackets connect the pair of mounting brackets by a panel member. The panel member is formed integrally with a connecting portion, and the panel member is located at a position corresponding to between the pair of spring support members, and the connecting portion is at a height position corresponding to an intermediate portion of the torsion beam in the vehicle width direction . It is characterized by being placed in

In the lower body structure of this electric vehicle, a pair of left and right mounting brackets are provided for fixing the rear part of the battery unit to the vehicle body, and the pair of mounting brackets connects the pair of mounting brackets by a panel member. It is integrally formed with the connecting part. Therefore, the rear part of the battery unit can be firmly supported with respect to the vehicle body while reducing the overall weight of the pair of mounting brackets and the connecting portion thereof .
Further, the panel member is disposed at a position corresponding to between a pair of spring support members of a torsion beam type suspension, and such that the connecting portion is at a height position corresponding to an intermediate portion of the torsion beam in the vehicle width direction. ing. Therefore, even though the panel members are formed to the minimum necessary size to reduce weight, even if the torsion beam is compressed and deformed in the event of a side collision to the rear of the vehicle, and the middle part in the width direction of the vehicle moves forward, The connecting portion can prevent the front end portion of the intermediate portion of the torsion beam in the vehicle width direction from moving forward, and direct interference between the front end portion of the intermediate portion of the torsion beam in the vehicle width direction and the battery unit can be avoided.

According to a second aspect of the present invention, in the first aspect of the present invention, the panel member includes a plurality of bead portions extending in the vertical direction of the vehicle body .
According to this configuration, the strength of the panel member can be increased.

The invention according to claim 3 is characterized in that in the invention according to claim 2 , the plurality of bead portions are formed in a convex shape protruding toward the rear of the vehicle body .
According to this configuration, when interference between the mounting bracket and the torsion beam or interference between the connecting portion and the torsion beam occurs, it is possible to ensure the separation distance between the torsion beam and the battery unit.

The invention according to claim 4 provides a floor panel having a front panel and a rear panel that extends rearward in the longitudinal direction of the vehicle through a kick-up panel that stands upward from the front panel, and a torsion beam type suspension disposed below the rear panel. and a battery unit disposed between the kick-up panel and the suspension, wherein the battery unit includes a bottom plate member on which a battery module is placed, and a battery unit disposed between the kick-up panel and the suspension; It has a first battery module placed on a bottom plate member and a second battery module placed above the first battery module, and the rear part of the battery unit is fixed to the vehicle body by a pair of left and right mounting brackets. The torsion beam of the suspension is disposed below the upper end of the second battery module in side view, and is attached to the pair of mounting brackets at a height corresponding to an intermediate portion of the torsion beam in the vehicle width direction. It is characterized by having a connecting part that connects the.

In the lower body structure of this electric vehicle, in order to ensure the cruising range of the vehicle, the rear part of the battery unit includes a first battery module, a second battery module placed above the first battery module, and a bottom plate member on which these are placed. Since the battery unit is fixed to the vehicle body by a pair of left and right mounting brackets, the rear part of the battery unit can be firmly supported to the vehicle body.
Further, the pair of mounting brackets are connected by a connecting part, and this connecting part is located at a height position corresponding to the middle part in the vehicle width direction of the torsion beam disposed below the upper end part of the second battery module. It is arranged. Therefore, even if the torsion beam is compressed and curved during a side collision to the rear of the vehicle and the middle part in the vehicle width direction advances forward, the front end part of the middle part in the width direction of the torsion beam is brought into contact with the coupling part and the front end part of the middle part in the width direction of the torsion beam is prevented from moving forward. Therefore, direct interference between the front end portion of the intermediate portion of the torsion beam in the vehicle width direction and the battery unit can be avoided.

The invention according to claim 5 is the invention according to claim 4 , wherein the battery unit includes a battery frame that supports the bottom plate member, and an upper cover member that cooperates with the bottom plate member to seal the battery module. The strength of the connecting portion is set higher than the strength of the rear end portion of the upper cover member .
According to this configuration, the weight of the upper cover member can be reduced, and the weight of the entire battery case can be reduced.

The invention according to claim 6 is the invention according to claim 5 , wherein the pair of mounting brackets has lower end portions joined to the rear wall portion of the battery frame, and upper end portions extending in the vehicle width direction formed on the rear panel. It is characterized by being joined to a closed cross-section member .
According to this configuration, the mounting strength of the mounting bracket can be increased, and displacement of the battery unit can be suppressed when interference occurs between the mounting bracket and the torsion beam or between the connecting portion and the torsion beam.

The invention according to claim 7 is characterized in that, in the invention according to any one of claims 1 to 6 , the pair of mounting brackets are arranged between the battery unit and the torsion beam .
According to this configuration, the connecting portion can be made smaller, and in the event of a rear collision of the vehicle, the forward movement of the torsion beam can be suppressed by the pair of mounting brackets, and direct interference between the torsion beam and the battery unit can be avoided. can.

The invention according to claim 8 is characterized in that, in the invention according to any one of claims 1 to 7 , a fuel tank is disposed on the rear side of the torsion beam.
According to this configuration, it is possible to suppress the forward movement of the torsion beam pushed by the fuel tank at the time of a rear collision of the vehicle.

According to the lower body structure of an electric vehicle of the present invention, interference between the torsion beam and the battery unit can be avoided by using the mounting bracket that fixes the rear part of the battery unit to the vehicle body.

FIG. 2 is a bottom view of the lower body of the electric vehicle according to the first embodiment. It is a perspective view seen from the rear side lower part. FIG. 3 is a rear view of the battery unit and rear suspension. FIG. 4 is a perspective view of the main part of FIG. 3; 4 is a sectional view taken along the line V-V in FIG. 3. FIG. FIG. 3 is an exploded perspective view of the battery unit. 6 is a sectional view taken along the line VII-VII in FIG. 5. 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 its uses.

Embodiment 1 of the present invention will be described below based on FIGS. 1 to 7.
The vehicle V according to the first embodiment is a hybrid vehicle whose driving sources include an internal combustion engine (not shown) such as a gasoline engine or a diesel engine, and a vehicle driving electric motor (motor generator) (not shown).

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

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

Next, the floor panel 2 will be explained.
The floor panel 2 is formed to span between a pair of side sills 1.
As shown in FIGS. 1 and 7, the floor panel 2 includes a front panel 2a on which a front passenger seat (not shown) is mounted, and a rear panel 2a that stands up upward from the rear end of the front panel 2a. The vehicle includes a rear panel 2b that extends rearward via a kick-up panel 2c and on which a rear passenger seat (not shown) is mounted. Both left and right end portions of the front panel 2a are joined to the inner walls of a pair of side sills 1 to form a front cabin floor surface, and both left and right end portions of the rear panel 2b are joined to a pair of rear side frames 4, respectively. This forms the rear passenger compartment floor surface.

As shown in FIG. 7, at the top (upper end) of the kick-up panel 2c, there is a first cross member 5 that cooperates with the lower surface of the kick-up panel 2c to form a closed section with a substantially rectangular cross-section extending left and right. It is arranged. Both ends of the first cross member 5 connect the front portions of the pair of rear side frames 4. At the rear of the first cross member 5, second and third cross members 6 and 7 having a generally hat-shaped cross section and 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 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 left and right. It forms a substantially rectangular closed cross section. In addition, these second and third cross members 6 and 7 cooperate to form a closed cross-section structure that extends from side to side with the rear panel 2b being sandwiched between them as a joint member, and also form a midway portion of the pair of rear side frames 4. are connected.

Next, the floor frame 3 and the pair of rear side frames 4 will be explained.
As shown in FIG. 1, each of the pair of floor frames 3 has 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 back and forth.

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 an outer wall in the vehicle width direction, and an inner panel that forms an inner wall in the vehicle width direction, and both panels cooperate to form a substantially rectangular closed cross section that extends back and forth. are doing. The 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 5, a pair of left and right tank support members 10 extending back and forth are connected to the middle portion of the fourth cross member 8, respectively. The pair of tank support members 10 are each formed in a closed cross section that gently curves downward, and are configured to support both left and right end portions of the fuel tank 9 from below. The front end of the tank support member 10 is fastened and fixed to the lower end of a battery frame 40 (described later) via a bolt (not shown), and the rear end is fastened and fixed to the lower end of the fourth cross member 8 via a fastening member. has been done.

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 to 3 and 5, 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. This is a torsion beam type suspension including torsion beams 22 extending left and right and connected to trailing arms 21, respectively.

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

On the inside part in the vehicle width direction from the middle part of the trailing arm 21 to the rear end part, there are a pair of left and right parts welded together so as to span the outside part in the vehicle width direction of the torsion beam 22 and the middle part of the trailing arm 21. A gusset 24 (spring support member) is provided. A compression coil spring (not shown) that cooperates with the shock absorber to constitute a vibration absorption mechanism of the vehicle V is mounted between these gussets 24 and the vehicle body, and the lower end of the compression coil spring is supported by the gusset 24. has been done.

As shown in FIGS. 1, 5, and 7, the torsion beam 22 corresponds between the kick-up panel 2c and the fuel tank 9 and between the tank support member 10 and the second cross member 6 in side view. arranged to correspond to the location. This torsion beam 22 is formed by crushing a cylindrical pipe member from a direction perpendicular to the axis to a longitudinal direction, and is formed by one half and the other half, and has an abbreviated 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 absorbed by 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 closed deformation.

Next, the battery unit 30 will be explained.
As shown in FIGS. 1, 2, 6, and 7, the battery unit 30 houses a high-voltage battery in which a plurality of (for example, 16) first and second battery modules 31 and 32 are connected in series. It is laid out in the space below the floor panel 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 power to the vehicle drive electric motor are rectangular parallelepiped battery aggregates in which a plurality of rectangular parallelepiped battery cells C each having a standard voltage are arranged in a stacked manner. The battery cell C is, for example, a lithium ion battery that is a type of secondary battery.

As shown in FIG. 6, the battery unit 30 includes first and second battery modules 31, 32, a first bottom plate member 33 on which twelve first battery modules 31 are mounted, and a first bottom plate member 33. The main components are an upper cover member 34 that cooperates to form a sealed space that accommodates the first and second battery modules 31 and 32, and a battery frame 40 that supports the first bottom plate member 33. 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, for example, an aluminum alloy plate, and has a rectangular tub shape. The first bottom plate member 33 is divided into three regions, a front region, an intermediate region, and a rear region, in order from the front.
Four first battery modules 31 are placed in each area in the left-right direction with the longitudinal direction parallel to the front-rear direction. Four second battery modules 32 are arranged above the four first battery modules 31 in the rear area. Note that the height position of the upper end of the first battery module 31 is arranged 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. They are set to the same specifications, including the height dimensions, that is, the same shape.

The upper cover member 34 is made of, for example, a synthetic resin material. The upper cover member 34 is configured such that the height of the portion covering the rear region of the first bottom plate member 33 is larger than the height of the portion covering the front region and the intermediate region. The outer edge of the upper cover member 34 is fastened and fixed to the outer edge of the first bottom plate member 33 by a plurality of fastening members with a sealing gasket (not shown) in between.

The battery frame 40 includes a pair of left and right first frames extending front and rear, and a pair of front and rear second frames extending left and right. Specifically, as shown in FIG. 6, the battery frame 40 includes a substantially square-shaped lower frame 41 and a substantially square-shaped lower frame 41 that cooperates with the lower frame 41 to form a closed cross section with a substantially rectangular cross section. The upper frame 42 is formed of a substantially square-shaped closed cross-section structure. Furthermore, this battery frame 40 has cross member members 43 to 45 that cooperate with the upper surface of the first bottom plate member 33 to form a closed cross section with a substantially rectangular cross section extending left and right between the pair of first frames. are doing. The first bottom plate member 33 has a front region divided by cross member members 43 and 44, a middle region divided by cross member members 44 and 45, and a rear region divided by the cross member member 45 and the rear end portion of the battery frame 40. It is divided by a corresponding rear second frame 46 (see FIG. 7).

The battery frame 40 is attached to the vehicle body using a plurality of (for example, 13) brackets 51 to 54. As shown in FIG. 6, 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. (panel member) is provided.

The pair of front brackets 51 are provided so as to protrude forward from the front wall of the second front frame, and are fastened and fixed to the lower surface of the front portion of the front panel 2a using bolts b2.
Each of the first side brackets 52 is provided so as to protrude outward in the vehicle width direction from the outer wall portion of the first frame in the vehicle width direction, and is fastened and fixed to the lower wall portion of the floor frame 3 using bolts b3. There is. A pair of second side brackets 53 are provided at the rear end of the first frame, respectively. As shown in FIGS. 2 and 6, the second side bracket 53 has a vertical wall portion extending vertically fixed to an outer wall portion in the vehicle width direction of the first frame, and extends from the upper end of the vertical wall portion outward in the vehicle width direction. A horizontal wall portion extending to is fastened and fixed to the lower wall portion of the floor frame 3 using bolts b4.

The rear bracket 54 is configured as a single part press-formed from a metal plate material, for example, a hot rolled steel plate. This rear bracket 54 is configured to have higher strength than at least the rear end portion of the upper cover member 34.
In this embodiment, the upper cover member 34 is made of synthetic resin and the rear bracket 54 is made of metal, but even if they are made of the same materials, the strength of the rear bracket 54 may vary depending on the plate thickness and structure. It may be higher.

As shown in FIGS. 1, 3, 5, and 7, the rear bracket 54 is disposed between the battery unit 30 and the torsion beam 22. Further, this rear bracket 54 is provided so as to correspond to an intermediate portion of the second rear frame 46, specifically, to a region sandwiched between a pair of left and right gussets 24 of the suspension 20.
As shown in FIGS. 3 and 4, the rear bracket 54 includes a pair of left and right mounting portions 55 (mounting brackets) and a connecting portion 56 that connects the pair of mounting portions 55.

The pair of attachment parts 55 are formed in a substantially L-shape, and each has a vertical wall part 55a extending vertically and a horizontal wall part 55b extending rearward from the upper end of the vertical wall part 55a.
As shown in FIG. 7, the lower part of the vertical wall part 55a is connected to the vertical wall part 46a of the second rear frame 46, in other words, to the nut n1 fixed to the rear wall part of the lower frame 41 via a bolt b5. Fastened and fixed. As a result, the vertical wall portion 55a is separated from the rear end portion of the upper cover member 34 by the longitudinal dimension of the second rear frame. The horizontal wall portion 55b is fastened and fixed to a pair of left and right nuts n2 fixed to the lower wall portion of the second cross member 6 via a pair of left and right bolts b6.

As shown in FIG. 3, the connecting portion 56 is provided over an area including a height position corresponding to the left-right intermediate portion 22a of the torsion beam 22. As shown in FIG. Specifically, a region from the lower end of the pair of attachment portions 55 to a position near the lower end of the rear wall portion of the lower frame 41 is connected.
The lower portion of the connecting portion 56 is fastened and fixed to a pair of left and right nuts (not shown) fixed to the rear wall portion of the lower frame 41 via a pair of left and right bolts b5.

The connecting portion 56 has a pair of left and right bead portions 56a formed near the boundary between the connecting portion 56 and the pair of attachment portions 55. These pair of bead portions 56a are arranged in the upper half of the connecting portion 56.
As shown in FIGS. 3 and 4, the bead portion 56a has a generally U-shaped cross section that projects rearward, and is configured to extend vertically. As a result, even if the torsion beam 22 moves forward in the event of a side collision to the rear of the vehicle body or a rear collision of the vehicle, the separation distance between the front end portion of the left-right intermediate portion 22a of the torsion beam 22 and the rear end portion of the upper cover member 34 is ensured. ing.

Next, the functions and effects of the above-mentioned lower vehicle body structure will be explained.
According to the lower body structure of the vehicle V , a pair of left and right mounting portions 55 (mounting brackets) are provided for fixing the rear portion of the battery unit 30 to the vehicle body , and the pair of mounting portions 55 are attached to the rear bracket 54. (panel member) is integrally formed with a connecting portion 56 that connects the pair of attachment portions 55. Therefore, the rear portion of the battery unit 30 can be firmly supported with respect to the vehicle body while reducing the overall weight of the pair of attachment portions 55 and their connecting portions 56 .
Further, the rear bracket 54 is located at a position corresponding to between a pair of left and right gussets 24 (spring support members) installed between a pair of left and right trailing arms 21 and a torsion beam 22 of the torsion beam type suspension 20. The connecting portion 56 is disposed at a height corresponding to the intermediate portion 22a of the torsion beam 22 in the left-right direction. Therefore, while reducing the weight by forming the rear bracket 54 with the minimum necessary size, the torsion beam 22 is curved and deformed in the event of a side collision to the rear of the vehicle body, resulting in the left-right intermediate portion 22a (vehicle widthwise intermediate portion). Even if the torsion beam 22 advances forward, the connecting portion 56 can prevent the left-right intermediate portion 22a from moving forward, thereby avoiding direct interference between the front end portion of the left-right intermediate portion 22a of the torsion beam 22 and the battery unit 30. can do.

Since the rear bracket 54 (panel member) includes a plurality of bead portions 56a extending in the vertical direction of the vehicle body, the strength of the rear bracket 54 can be increased.

The plurality of bead portions 56a are formed in a convex shape protruding toward the rear of the vehicle body. Therefore, when interference occurs between the mounting portion 55 (mounting bracket) and the torsion beam 22 or between the connecting portion 56 and the torsion beam 22, it is possible to ensure the separation distance between the torsion beam 22 and the upper cover member 34 of the battery unit 30. can.

Further, according to the lower body structure of the vehicle V, in order to ensure the cruising distance of the vehicle V, the first battery module 31, the second battery module 32 disposed above the first battery module 31, and the first bottom plate on which these are mounted. Since the rear part of the battery unit 30 having the member 33 (bottom plate member) is fixed to the vehicle body by a pair of left and right mounting parts 55 (mounting brackets), the rear part of the battery unit 30 can be firmly supported to the vehicle body. I can do it.
The pair of left and right mounting portions 55 are connected by a connecting portion 56, and this connecting portion 56 connects to the left-right intermediate portion 22a (vehicle width The height position corresponds to the middle part of the direction. Therefore, even if the torsion beam 22 is compressed and curved and its left-right intermediate portion 22a advances forward during a side impact to the rear of the vehicle, it can be brought into contact with the connecting portion 56. Therefore, in the event of a side collision to the rear of the vehicle body, the front end portion of the left-right intermediate portion 22a of the torsion beam 22 can be prevented from advancing by the connecting portion 56, and the front end portion of the left-right intermediate portion 22a of the torsion beam 22 and the battery unit 30 can be prevented from moving forward. It is possible to avoid direct interference with

The battery unit 30 includes a battery frame 40 that supports a first bottom plate member 33 (bottom plate member), and an upper part that cooperates with the first bottom plate member 33 to seal the first and second battery modules 31 and 32 (battery modules). It has a cover member 34. Since the strength of the connecting portion 56 is set higher than the strength of the rear end of the upper cover member 34, the weight of the upper cover member 34 can be reduced, and the weight of the entire battery case can be reduced. .

The pair of mounting portions 55 (mounting brackets) have lower ends joined to the rear wall of the battery frame 40 (lower frame 41), and upper ends connected to a second cross member 6 formed on the rear panel 2b and extending in the vehicle width direction. (closed cross-section member). Therefore, the mounting strength of the mounting portion 55 can be increased, and the displacement of the battery unit 30 can be suppressed when interference occurs between the mounting portion 55 and the torsion beam 22 or between the connecting portion 56 and the torsion beam 22. .

A pair of mounting portions 55 (mounting brackets) are arranged between the battery unit 30 and the torsion beam 22 . Therefore, the connecting portion 56 can be made smaller, and in the event of a rear collision of the vehicle, the forward movement of the torsion beam 22 can be suppressed by the pair of attachment portions 55, and direct interference between the torsion beam 22 and the battery unit 30 can be avoided. I can do it.

Since the fuel tank 9 is disposed on the rear side of the torsion beam 22, the forward movement of the torsion beam 22 pushed by the fuel tank 9 can be suppressed in the event of a rear collision of the vehicle.

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

2] In the embodiment described above, an example of the battery unit 30 was described in which the first battery module 31 is housed below the front panel 2a, and the first and second battery modules 31, 32 are housed below the rear panel 2b. Any arrangement structure in which the battery unit 30 is disposed between the kick-up panel 2c and the suspension 20, regardless of whether it is a single layer or multiple layers, is sufficient, and only the battery modules stacked vertically can be placed on the rear side of the kick-up panel 2c. It may be the battery unit 30 that is placed.

3] In the above embodiment, an example was explained in which the pair of attachment portions 55 were fastened to the vertical wall portion 46a of the rear second frame 46, but the pair of attachment portions 55 were fastened to the vehicle of the pair of first frames. It may be fixed to the rear end of the outer wall in the width direction. In this case, the connecting portion 56 that connects each attachment portion 55 fixed to the rear end of the outer wall in the vehicle width direction of the first frame has an area in the center portion in the vehicle width direction that is larger than an area in the outer portion in the vehicle width direction. It is preferable to set it large.
In addition, although an example has been described in which the pair of mounting portions 55 and the connecting portion 56 are integrally molded from the same steel plate, the pair of mounting portions 55 and the connecting portion 56 are molded separately and are later assembled to form the rear bracket 54. may be formed.

4] In the above embodiment, an example has been described in which the intermediate portion 22a is approximately the central portion in the longitudinal direction of the torsion beam 22. However, in the event of a side collision to the rear of the vehicle body, the intermediate portion 22a is compressed and curved due to a collision load directed inward in the vehicle width direction. By advancing forward, the intermediate portion in the longitudinal direction of the torsion beam 22 that may interfere with the battery unit 30 corresponds to the intermediate portion 22a of the torsion beam 22, and the same effects as the present invention can be achieved. Furthermore, since the torsion beam 22 is twisted due to a side collision, the front end portion of the intermediate portion 22a is not limited to the front lower end portion of the torsion beam 22 before the side collision.

5] In addition, those skilled in the art will be able to implement various modifications to the embodiments described above or combinations of the embodiments without departing from the spirit of the present invention, and the present invention can be implemented in such a manner. It also includes any modifications.

2 Floor panel 2a Front panel 2b Rear panel 2c Kick-up panel 6 Second cross member 9 Fuel tank 20 Rear suspension 21 Trailing arm 22 Torsion beam 24 Gusset 30 Battery unit 31 First battery module 32 Second battery module 33 First bottom plate member 34 Upper cover member 40 Battery frame 54 Rear bracket 55 Mounting part 56 Connecting part 56a Bead part V Vehicle

Claims (8)

a floor panel having a front panel and a rear panel extending rearward in the longitudinal direction of the vehicle through a kick-up panel standing upward from the front panel; a torsion beam suspension disposed below the rear panel; and the kick-up panel. A lower vehicle body structure for an electric vehicle including a battery unit disposed between the suspension and the suspension,
The suspension includes a pair of left and right trailing arms whose front ends are pivotally supported by the vehicle body and whose rear ends rotatably support wheels, a torsion beam connected to the pair of trailing arms, and a torsion beam connected to the pair of trailing arms. a pair of left and right spring support members installed between the trailing arm and the torsion beam;
A rear part of the battery unit is fixed to the vehicle body by a pair of left and right mounting brackets ,
The pair of mounting brackets are integrally formed with a connecting portion that connects the pair of mounting brackets by a panel member,
The panel member is disposed at a position corresponding to between the pair of spring support members, and such that the connecting portion is at a height position corresponding to an intermediate portion of the torsion beam in the vehicle width direction. Characteristic lower body structure of electric vehicles. The lower vehicle body structure for an electric vehicle according to claim 1, wherein the panel member includes a plurality of bead portions extending in the vertical direction of the vehicle body. 3. The lower vehicle body structure for an electric vehicle according to claim 2, wherein the plurality of bead portions are formed in a convex shape projecting toward the rear of the vehicle body. a floor panel having a front panel and a rear panel extending rearward in the longitudinal direction of the vehicle through a kick-up panel standing upward from the front panel; a torsion beam suspension disposed below the rear panel; and the kick-up panel. A lower vehicle body structure for an electric vehicle including a battery unit disposed between the suspension and the suspension,
The battery unit includes a bottom plate member on which a battery module is placed, a first battery module placed on the bottom plate member as the battery module, and a second battery module placed above the first battery module. death,
A rear part of the battery unit is fixed to the vehicle body by a pair of left and right mounting brackets,
The torsion beam of the suspension is disposed below the upper end of the second battery module in side view,
A lower body structure for an electric vehicle, comprising a connecting portion connecting the pair of mounting brackets at a height position corresponding to an intermediate portion of the torsion beam in the vehicle width direction. The battery unit includes a battery frame that supports the bottom plate member, and an upper cover member that cooperates with the bottom plate member to seal the battery module.
The lower vehicle body structure for an electric vehicle according to claim 4, wherein the strength of the connecting portion is set higher than the strength of the rear end portion of the upper cover member. The pair of mounting brackets are characterized in that lower end portions are joined to the rear wall portion of the battery frame, and upper end portions are joined to a closed cross-section member formed on the rear panel and extending in the vehicle width direction. 5. The lower body structure of the electric vehicle according to 5. The lower vehicle body structure for an electric vehicle according to any one of claims 1 to 6, wherein the pair of mounting brackets are arranged between the battery unit and the torsion beam. The lower vehicle body structure for an electric vehicle according to any one of claims 1 to 7, characterized in that a fuel tank is disposed on the rear side of the torsion beam.