JP7084813B2 - Battery pack mounting structure - Google Patents

Description

The present invention relates to a structure in which a battery pack of an electric vehicle is mounted on a vehicle body.

For example, in an electric vehicle such as an electric vehicle or an engine-electric hybrid vehicle, a battery pack in which a large number of battery cells such as a lithium ion battery and a nickel hydrogen battery are housed in a container-shaped housing and unitized is provided at the rear of the vehicle body. It is installed in the center floor and so on.
As a conventional technique relating to a battery pack mounting structure of an electric vehicle, for example, Patent Document 1 aims to reduce the vibration antinode amplitude of the vehicle floor due to the weight of the battery, and front and rear sides of the center portion of the floor panel. It is stated that the battery bracket is provided, the front battery bracket is located on the floor undercarriage, and the rear battery bracket is located on the center cross member.

Japanese Unexamined Patent Publication No. 2013-107592

In automobiles such as passenger cars with a monocoque structure, when a heavy battery pack is attached to the floor, the natural frequency of the vehicle body may change and elastic vibration may worsen, causing noise and ride quality deterioration. be.
For example, when the battery pack is mounted on the rear part of the floor, there is a concern that the vibration in the elastic vibration mode, in which the distance between the upper end of the front window glass and the rear part of the floor expands and contracts, deteriorates and causes noise such as muffled noise. To.
It is conceivable to reinforce the vehicle body and change the natural frequency to deal with such deterioration of vibration, but in this case, the structure of the vehicle body becomes complicated and the weight and cost increase.
Further, as in the technique described in Patent Document 1, it is conceivable to suppress the amplitude of the anti-vibration portion by the weight of the battery, but the damping effect is limited by simply loading the weight of the battery. It becomes a thing.
In view of the above-mentioned problems, an object of the present invention is to provide a battery pack mounting structure that effectively suppresses elastic vibration of a vehicle body by a simple and lightweight configuration.

The present invention solves the above-mentioned problems by the following solution means.
The invention according to claim 1 is a battery pack mounting structure including a floor portion provided in a lower portion of a vehicle body and a battery pack configured by accommodating a battery cell in a container and attached to the floor portion. The vertical support rigidity of the pack with respect to the floor portion is lower than that of the other on one of the front side and the rear side, and the side having the low support rigidity is elastically vibrating the floor portion with respect to the side having the high support rigidity. It is a battery pack mounting structure characterized by being arranged so as to be close to the abdomen of the mode.
According to this, by making the support rigidity in the vertical direction of the battery pack different in the front-rear direction, it is possible to induce a pitching behavior in which the side with the low support rigidity swings up and down with the side with the high support rigidity as the fulcrum. ..
By arranging the side with large vibration due to this pitching behavior closer to the antinode part of the elastic vibration mode of the floor part, the mass of the battery pack acts as a mass damper (dynamic vibration absorber) to control the floor part. It exerts a vibration effect and can effectively suppress the elastic vibration of the vehicle body due to its simple and lightweight configuration.
In addition, the effect on the natural frequency of each part of the vehicle body is small, and adverse effects such as deterioration of resonance in other modes are unlikely to occur.
In the present specification and claims, the vibration antinode is not limited to one point where the amplitude is maximum, but refers to a node or a portion excluding a portion adjacent to the node.

The invention according to claim 2 is a battery pack support member which is formed of an elastic material so as to extend in the front-rear direction of the vehicle, is attached to a structural member of the vehicle body at a front end portion and a rear end portion, and supports the battery pack. The first aspect of the present invention is characterized in that the position of the center of gravity of the battery pack is arranged at a position far from the antinode portion of the elastic vibration mode with respect to the center position of the battery pack support member in the front-rear direction. Battery pack mounting structure.
The invention according to claim 3 is a battery pack support member which is formed of an elastic material so as to extend in the front-rear direction of the vehicle, is attached to a structural member of the vehicle body at a front end portion and a rear end portion, and supports the battery pack. The center position of the range in which the battery pack support member and the battery pack are coupled to the center position in the front-rear direction of the battery pack support member is located far from the antinode portion of the elastic vibration mode. The battery pack mounting structure according to claim 1, wherein the battery pack is mounted.
According to each of these inventions, the simple and lightweight configuration causes a pitching behavior in which the end portion of the battery pack on the side close to the antinode portion of the elastic vibration mode swings, and the above-mentioned effect can be obtained.

The invention according to claim 4 includes a pair of side frames extending in the front-rear direction along the floor portion and spaced apart from each other in the vehicle width direction, and the front end portion and the rear end portion of the battery pack support member are provided. The battery pack mounting structure according to claim 2 or 3, wherein the battery pack is connected to the side frame.
According to this, since the attachment point of the battery pack support member to the vehicle body is strong, the pitching behavior of the battery pack can be reliably induced in a more stable state.

The invention according to claim 5 is a reinforcing portion provided at a portion of the floor portion that coincides with or is close to the abdominal portion of the elastic vibration mode and is reinforced with respect to the other portion of the floor portion.
The battery pack according to any one of claims 1 to 4, further comprising a connecting member for connecting the end portion of the battery pack on the side having a low support rigidity and the reinforcing portion. It is a mounting structure.
According to this, it is possible to surely transmit the load between the end portion on the side where the battery pack swings due to the pitching behavior and the floor portion adjacent to the end portion, and the vibration damping effect can be further enhanced.

The invention according to claim 6 is a battery pack mounting structure including a floor portion provided in a lower portion of a vehicle body and a battery pack configured by accommodating a battery cell in a container and attached to the floor portion. The pack is fixed to the floor portion on one of the front side and the rear side, and the other side can swing in the vertical direction with respect to the fixed portion with the floor portion due to the elastic deformation of the container, so that the pack can swing. The battery pack mounting structure is characterized in that the side is arranged so as to be close to the antinode portion of the elastic vibration mode of the floor portion with respect to the fixed portion.
According to this, the end portion on the side opposite to the fixed side of the battery pack (the ventral end portion of the elastic vibration mode of the floor portion) exhibits elastic deformation that swings in the vertical direction, thereby causing the battery pack to swing. The mass near the end of the side acts as a mass damper to exert a vibration damping effect on the floor, and the simple and lightweight configuration can effectively suppress the elastic vibration of the vehicle body.

The invention according to claim 7 comprises a reinforcing portion provided at a portion corresponding to or adjacent to the abdominal portion of the elastic vibration mode of the floor portion and reinforced with respect to the other portion of the floor portion, and the battery pack. The battery pack mounting structure according to claim 6, further comprising a connecting member for connecting the swingable side end portion and the reinforcing portion.
According to this, it is possible to surely transmit the load between the end portion on the side where the battery pack swings due to elastic deformation and the floor portion adjacent to the end portion, and the vibration damping effect can be further enhanced.

The invention according to claim 8 is the invention according to claim 5 or 7, wherein the reinforcing portion is a cross member having a closed cross-sectional portion extending in the vehicle width direction along the floor portion. It has a battery pack mounting structure.
According to this, by utilizing the existing structural members of the vehicle body, the above-mentioned effects can be obtained while suppressing an increase in the number of parts and complication of the structure.

As described above, according to the present invention, it is possible to provide a battery pack mounting structure that effectively suppresses elastic vibration of the vehicle body by a simple and lightweight configuration.

It is a figure which looked at the side view of the vehicle which has the 1st Embodiment of the battery pack mounting structure to which this invention was applied. It is a top view (the arrow view of the part II-II of FIG. 1) which looked at the rear part of the floor of the vehicle of FIG. 1 from above. FIG. 1 is a perspective view of the rear part of the floor of the vehicle of FIG. 1 as viewed diagonally upward and diagonally from the front side, and is a diagram showing a state before mounting the battery pack. FIG. 1 is a perspective view of the rear part of the floor of the vehicle of FIG. 1 as viewed diagonally upward and diagonally from the front side, and is a diagram showing a state after the battery pack is mounted. It is a schematic exploded view which looked at the battery pack mounting structure of 1st Embodiment from the vehicle width direction. It is a figure which shows typically the behavior of the battery pack in the battery pack mounting structure of 1st Embodiment. It is a schematic exploded view which looked at the 2nd Embodiment of the battery pack mounting structure to which this invention was applied from the vehicle width direction. It is a schematic diagram which looked at the 3rd Embodiment of the battery pack mounting structure to which this invention was applied from the vehicle width direction.

Hereinafter, the first embodiment of the battery pack mounting structure to which the present invention is applied will be described.
The battery pack mounting structure of the first embodiment is provided in, for example, an automobile such as a passenger car and an electric vehicle such as an engine-electric hybrid vehicle having a plug-in charging function.

FIG. 1 is a side view of a vehicle having the battery pack mounting structure of the first embodiment.
The vehicle 1 includes a cabin 100, a floor portion 110, an A pillar 120, a B pillar 130, a C pillar 140, a D pillar 150, a roof 160, a front side door 170, a rear side door 180, a rear fender 190, a rear gate 200, a rear bumper face 210, and an engine. It includes a compartment 220, a hood 230, a front end module 240, a front bumper face 250, a front fender 260, a front wheel house 270, a rear wheel house 280, a rear floor portion 300, and the like.

The cabin (vehicle compartment) 100 is a main body of a vehicle body having a space for accommodating occupants and the like.
Inside the cabin 100, front seat FS and rear seat RS on which the occupant sits are arranged in the front and rear.
The main part of the vehicle body including the cabin 100 is configured as a monocock structure in which, for example, panels pressed with steel plates are assembled and joined by electric resistance spot welding, laser welding, structural adhesive, or the like.

The floor portion 110 is a portion constituting the floor surface portion of the cabin 100.
The floor portion 110 has a structure reinforced by joining, for example, a floor panel formed by pressing a steel plate to a reinforcing structure such as various frames, cross members, and side sills.
Further, the structure of the rear floor portion 300, which is the latter half of the floor portion 110, will be described in detail later.

The A-pillar 120, B-pillar 130, C-pillar 140, and D-pillar 150 are portions extending in the vertical direction along the side surface of the vehicle body, are formed in a columnar shape having a closed cross section, and are sequentially arranged from the front side of the vehicle. Has been done.
The A-pillar 120 projects upward from the front end portion of the side sill arranged along the side end portion of the floor portion 110, and the upper half portion is arranged so as to be tilted backward.
A front window glass 121 is provided at a distance between the left and right A pillars 120.

The B-pillar 130 projects upward from the middle portion of the side sill.
The C-pillar 140 and the D-pillar 150 are arranged from above the rear wheel house 280 to the side end portion of the roof 160.

The roof 160 is a member constituting the upper surface portion (ceiling portion) of the cabin 100.
The roof 160 is configured by reinforcing the lower surface side of the roof panel that forms a part of the vehicle exterior with a roof side frame or a cross member (not shown).
The front end portion of the roof 160 is arranged adjacent to the upper end portion of the front window glass 121.
The upper ends of the A-pillar 120, the B-pillar 130, the C-pillar 140, and the D-pillar 150 are connected to a roof side frame (not shown) at the side end of the roof 160.

The front side door 170 is a door-like body that can be opened and closed at the front door opening on which an occupant seated on the front seat FS gets on and off.
The front door opening is provided between the A pillar 120 and the B pillar 130.
The front side door 170 is swingably attached around a hinge attached to the A pillar 120.

The rear side door 180 is a door-like body that can be opened and closed at the rear door opening on which an occupant seated on the rear seat RS gets on and off.
The rear door opening is provided between the B pillar 130 and the C pillar 140.
The rear side door 180 is swingably attached around a hinge attached to the B pillar 130.

The rear fender 190 is a vehicle body outer plate provided on the rear side of the rear side door 180.
The upper edge of the rear foil house 280 is formed in the lower part of the rear fender 190.
A rear combination lamp, which is a lighting device, is provided at the rear end of the rear fender 190.

The rear gate 200 is a door-like body that is openably and closably attached to an opening provided at the rear end of the vehicle body.
The rear gate 200 is opened and closed by rotating around a hinge provided at the rear end of the roof 160.
The rear bumper face 210 is a resin exterior member provided below the rear gate 200 at the rear end of the vehicle body.

The engine compartment 220 is provided on the front side of the cabin 100 and has a space for accommodating a power train such as an engine, a motor generator, and a transmission (not shown).
The hood 230 is a lid-shaped exterior member provided on the upper part of the engine compartment 220 so as to be openable and closable.

The front end module 240 is a unit having a heat exchanger such as a radiator and a condenser of an air conditioner provided at the front end of the vehicle body, an electric fan provided in these heat exchangers, a front combination lamp which is a lighting device, and the like. ..
The front bumper face 250 is a resin exterior member provided at the front end of the vehicle body.
The front fender 260 is a vehicle body outer panel provided on the side of the engine compartment 220.
The upper edge of the rear wheel house 270 is formed in the lower part of the front fender 260.

The front foil house 270 and the rear foil house 280 are space portions in which the front wheel FW and the rear wheel RW are housed, respectively.
The front foil house 270 is provided on the side of the engine compartment 220.
The rear wheel house 280 is provided near the lower part of the rear fender 190 and on the side of the rear floor portion 300.

The rear floor portion 300 is a portion constituting a floor surface portion (rear portion of the floor portion 110) in the rear portion of the cabin 100.
A battery pack 400, which will be described later, is mounted on the upper surface side of the rear floor portion 300.

Hereinafter, the structure of the rear floor portion 300 and the mounting structure of the battery pack 400 will be described in more detail.
FIG. 2 is a plan view of the rear part of the floor of the vehicle of FIG. 1 as viewed from above (arrow view of part II-II of FIG. 1).
FIG. 3 is a perspective view of the rear part of the floor of the vehicle of FIG. 1 as viewed diagonally upward and diagonally from the front side, and is a view showing a state before mounting the battery pack.
FIG. 4 is a perspective view of the rear part of the floor of the vehicle of FIG. 1 as viewed diagonally upward and diagonally from the front side, and is a view showing a state after the battery pack is mounted.
FIG. 5 is a schematic exploded view of the battery pack mounting structure of the first embodiment as viewed from the vehicle width direction.
FIG. 5 shows an exploded view of the cross section taken along the line VV in FIG. 2.

The rear floor portion 300 is provided with a rear floor panel 310, a side frame 320, a first cross member 330, a second cross member 340, and the like.
The rear floor panel 310 is a panel-shaped member that constitutes a floor surface portion in the rear portion of the cabin 100.
The rear floor panel 310 is formed, for example, by press-molding a steel plate.
Below the rear floor panel 310, a fuel tank (not shown), rear suspension arms, a rear subframe (not shown) to which a rear differential is attached, and the like are arranged.

The side frame 320 is a structural member extending in the front-rear direction of the vehicle along the side end portion of the rear floor panel 310.
The side frame 320 is formed so that the cross-sectional shape seen from the front-rear direction of the vehicle becomes a rectangular closed cross-section by, for example, assembling members obtained by press-molding steel plates and joining them by spot welding or the like.

The side frame 320 has a front portion 321 and an intermediate portion 322 and a rear portion 323 that are continuously and integrally formed in order from the front side.
The front portion 321 is arranged along the front-rear direction of the vehicle, and is connected to the left and right side ends of the first cross member 330, respectively.
The front portion 321 is coupled to a front side frame, a side sill, etc., which are structural members extending in the front-rear direction at the front portion of the vehicle body, via a first cross member 330.
The intermediate portion 322 is an area provided between the front portion 321 and the rear portion 323.
The rear portion 323 is arranged along the vehicle front-rear direction in the rear portion of the side frame 320.

The intermediate portion 322 is formed so as to be inclined with respect to the vehicle front-rear direction so that the rear end portion is upward and inside in the vehicle width direction with respect to the front end portion.
As a result, the side frame 320 is formed so that the shapes seen from above and from the side surface are curved in an S shape, respectively, and the rear portion 323 is upward and the vehicle when viewed from the front and rear direction of the vehicle with respect to the front portion 321. It is arranged offset inward in the width direction.
The rear wheel house 280 described above is arranged in a region outside the rear wheel 323 in the vehicle width direction.
Further, the rear portion 323 is provided with a mount portion 324 to which the upper end portion of the damper spring unit (not shown) of the rear suspension is attached.
The mount portion 324 is formed so as to project outward in the vehicle width direction from the rear portion 323.

The first cross member 330 and the second cross member 340 are structural members extending along the vehicle width direction between the left and right side frames 320.
In the first cross member 330 and the second cross member 340, for example, members obtained by press-molding steel plates are assembled and joined by spot welding or the like so that the cross-sectional shape seen from the vehicle width direction becomes a rectangular closed cross section. Is formed in.

The first cross member 330 is provided between the front ends of the front portions 321 of the left and right side frames 320.
The first cross member 330 is arranged along the leading edge of the rear floor panel 310.
A front side frame and a rear end portion of a side sill, which are structural members arranged so as to extend in the front-rear direction along the floor portion 110 on the front side thereof, are connected to the first cross member 330.

The second cross member 340 is provided between the middle portions 322 of the left and right side frames 320.
The second cross member 340 is configured to have a closed cross section on the lower surface side of the rear floor panel 310 by joining a panel having an inverted hat-shaped cross-sectional shape with an open upper portion to the lower surface side of the rear floor panel 310. ..
The second cross member 340 is joined to the rear floor panel 310 by spot welds discretely arranged along the longitudinal direction, or by continuously formed laser welds, structural adhesives, and the like. ..
The periphery of the second cross member 340 is an antinode (a portion other than the node) in the elastic vibration of the vehicle body collapse mode described later. That is, the second cross member 340 is a reinforcing portion provided at a portion that coincides with or is close to the antinode portion of the elastic vibration mode of the rear floor panel 310.

The battery pack 400 has a high-voltage battery that charges the electric power generated by the motor generator of the vehicle and the electric power supplied from the outside during parking, and supplies the electric power for traveling to the motor generator.
The battery pack 400 is, for example, a battery ECU which is a control device for managing a plurality of lithium ion battery cells and their current, voltage, temperature, SOC, etc. inside a container-shaped housing formed by press-molding a metal plate. , A cooling device for cooling each cell and the like are housed in the battery.
As shown in FIG. 4 and the like, the battery pack 400 is mounted on the upper side of the area on the upper side of the rear floor portion 300 and on the rear side of the second cross member 340.
The battery pack 400 may have a mass of, for example, about 150 kg, depending on the capacity.

The battery pack 400 is attached to the side frame 320 via the battery bracket 500.
The battery bracket 500 is provided at each of the left and right side ends of the battery pack 400.
The battery bracket 500 is integrally formed of an elastic material.
For example, in the case of the first embodiment, the battery bracket 500 is formed to function as a kind of leaf spring by, for example, by press-molding a highly elastic steel plate to exhibit elastic deformation that becomes an overall bow shape. There is.

The battery bracket 500 is formed in a panel shape extending in the front-rear direction, and is configured by integrally forming a front portion 510, an intermediate portion 520, and a rear portion 530.
As shown in FIG. 2, the battery bracket 500 is formed in a band shape extending along the vehicle front-rear direction in a vehicle plan view viewed from above.
The front portion 510, the intermediate portion 520, and the rear portion 530 are sequentially and continuously provided from the front side.
As shown in FIG. 5 and the like, the front portion 510 is tilted forward so that the front end portion is lowered with respect to the rear end portion.
The front portion 510 is arranged so as to project toward the front side of the vehicle with respect to the front end portion of the battery pack 400.
In the vicinity of the front end portion of the front portion 510, a fastening portion 511 to be fastened to the upper surface portion of the intermediate portion 322 of the side frame 320 is provided.

The rear portion 530 extends substantially horizontally along the upper surface portion of the rear portion 321 of the side frame 320.
In the vicinity of the rear end portion of the rear portion 530, a fastening portion 531 to be fastened to the upper surface portion of the rear portion 323 of the side frame 320 is provided.
The intermediate portion 520 is formed so as to be curved so as to be convex upward in the side view of the vehicle so that the inclination with respect to the vehicle front-rear direction continuously gradually changes between the front portion 510 and the rear portion 530.
The front end of the battery pack 400 is located above the middle 520.

The lower surface portion of the battery bracket 500 is provided with a space between the lower surface portion of the battery bracket 500 and the upper surface portion of the side frame 320 in a region other than the fastening portion 511,531 so as to allow the battery pack 400 to swing, which will be described later.
The rear portion 530 of the battery bracket 500 is fixed to the lower portion of the battery pack 400 at a plurality of fixing points P1, P2, and P3 (three places in the first embodiment as an example) distributed in the front-rear direction of the vehicle. ..

As shown in FIG. 5, the center of gravity position CG of the battery pack 400 is offset to the rear side of the vehicle with respect to the center position Cb in the front-rear direction of the battery bracket 500.
Further, the battery bracket 500 is configured to be able to be elastically deformed in a direction in which the curvature of the curved portion of the intermediate portion 520 changes due to the exciting force acting on the battery pack 400 when the vehicle is running.

The center bracket 600 is a connecting member that vertically connects the central portion in the vehicle width direction at the front end portion of the battery pack 400 and the central portion in the vehicle width direction of the rear floor panel 310 directly above the second cross member 340.
The center bracket 600 can transmit a load in the vertical direction between the front portion of the battery pack 400 and the second cross member 340.

FIG. 6 is a diagram schematically showing the behavior of the battery pack in the battery pack mounting structure of the first embodiment.
In the battery pack mounting structure of the first embodiment, the battery bracket 500 is provided with a curved intermediate portion 520, and the battery bracket 500 is elastically deformed so that the front portion 510 and the rear portion 530 rotate relative to each other due to the elastic deformation thereof. It is configured as follows.
Further, since the center of gravity position CG of the battery pack 400 is offset to the rear side from the center position Cb in the front-rear direction of the battery bracket 500, the support rigidity in the vertical direction of the battery pack 400 with respect to the vehicle body (side frame 320) is high. , It is lower on the front side than on the rear side (the vertical spring constant is smaller).

In this case, when a vibration force in the vertical direction is applied to the battery pack 400, the battery bracket 500 is elastically deformed so as to be around the rotation center axis extending along the vehicle width direction in the vicinity of the rear end portion of the battery pack 400. The front end portion of the battery pack 400 exhibits a pitching behavior of swinging in the vertical direction.
This pitching behavior is linked to the elastic vibration in the vertical direction in the central portion of the second cross member 340 by connecting the second cross member 340 and the front end portion of the battery pack 400 with the center bracket 600.
At this time, a part of the mass of the battery pack 400 functions as a mass damper that suppresses the vibration of the rear floor panel 310 around the second cross member 340.

Generally, in an automobile such as a passenger car having a monocock structure, when a heavy battery pack is mounted on the rear floor, a point A near the upper end of the front window glass 121 and a point B near the second cross member 340 are used. Deterioration of noise such as muffled noise due to elastic vibration (vibration in the so-called vehicle body crushing mode) in which the cabin 100 is deformed in the direction in which the distance from (see FIG. 1) expands and contracts tends to be a problem.
In this regard, according to the first embodiment, the mass of the battery pack 400 functions as a mass damper, which effectively suppresses such elastic vibration of the vehicle body, and is simple and lightweight with almost no increase in the number of parts or mass. Depending on the configuration, noise caused by vehicle body vibration can be suppressed.

As described above, according to the first embodiment, the following effects can be obtained.
(1) By making the support rigidity of the battery pack 400 in the vertical direction different from front to back, the side with low support rigidity (front part) swings up and down with the side with high support rigidity (rear part) as the fulcrum of the battery pack 400. It is possible to generate a pitching behavior.
By arranging the side (front part) having a large vibration due to this pitching behavior closer to the second cross member 340 side adjacent to the antinode portion B of the elastic vibration mode of the rear floor portion 300, the battery pack 400 The mass acts as a mass damper to exert the vibration damping effect of the floor portion 100, and the elastic vibration of the vehicle body can be effectively suppressed by the simple and lightweight configuration.
In addition, the effect on the natural frequency of each part of the vehicle body is small, and adverse effects such as deterioration of resonance in other modes are unlikely to occur.
(2) The position of the center of gravity of the battery pack 400 is arranged at a position (rear of the vehicle) far from the antinode portion B of the elastic vibration mode with respect to the center position Cb in the front-rear direction of the battery bracket 500 formed of the elastic material. As a result, the pitching behavior in which the front end portion of the battery pack 400 swings up and down is generated by a simple and lightweight configuration, and the above-mentioned effect can be obtained.
(3) By setting the attachment point of the battery bracket 500 to the vehicle body as the side frame 320, which is a relatively strong part in the rear floor portion 300, the pitching behavior of the battery pack 400 can be surely obtained in a more stable state. be able to.
(4) By connecting the front end portion on the side where the battery pack 400 swings and the second cross member 340 which is a reinforcing portion in the rear floor portion 300 with the center bracket 600, the battery pack 400 swings due to the pitching behavior. It is possible to reliably transmit the load between the end portion on the side where the load is applied and the rear floor portion 300 adjacent to the end portion, and the vibration damping effect can be further enhanced.
Further, by using the second cross member 340 as the connecting portion of the center bracket 600 on the vehicle body side, the above-mentioned effect can be obtained while suppressing an increase in the number of parts and complication of the structure.

<Second Embodiment>
Next, a second embodiment of the battery pack mounting structure to which the present invention is applied will be described.
In each of the embodiments described below, the parts substantially the same as those of the previous embodiments are designated by the same reference numerals, the description thereof will be omitted, and the differences will be mainly described.
FIG. 7 is a schematic exploded view of the battery pack mounting structure of the second embodiment as viewed from the vehicle width direction.
As shown in FIG. 7, in the region where the fixing points P1 to P3 between the battery pack 400 and the battery bracket 500 are provided, the reinforcing region R in which the battery bracket 500 is reinforced (stiffened) by the rigidity of the battery pack 400 itself. Is formed.

In the second embodiment, in order to enable the same swing of the battery pack 400 as in the first embodiment, the center position Cr in the vehicle front-rear direction of the reinforcing region R (the frontmost fixed portion P1 and the rearmost fixed portion P1). The position (intermediate position with the position P3) is arranged on the rear side of the vehicle with respect to the intermediate position Cb of the battery bracket 500.
Also in the second embodiment described above, the same effect as that of the first embodiment described above can be obtained.

<Third Embodiment>
Next, a third embodiment of the battery pack mounting structure to which the present invention is applied will be described.
FIG. 8 is a schematic view of a third embodiment of the battery pack mounting structure to which the present invention is applied as viewed from the vehicle width direction.
In the third embodiment, the battery bracket 700 described below is provided in place of the battery bracket 500 of the first embodiment.
The battery bracket 700 firmly connects the area on the rear side of the vehicle in the lower part of the battery pack 400 and the upper surface portion of the rear portion 323 of the side frame 320 with high rigidity so that deformation during running of the vehicle can be ignored. Is.
On the other hand, the area on the front side of the vehicle of the battery pack 400 is attached to the rear floor portion 300 only by the center bracket 600 (not shown in FIG. 8).
The position of the center of gravity of the battery pack 400 is arranged on the front side of the vehicle with respect to the front end portion of the battery bracket 700.

In the third embodiment, the housing of the battery pack 400 is elastically deformed by the exciting force acting on the battery cell, which is a heavy object in the battery pack 400, when the vehicle is running, and the front end portion of the battery pack 400 is on the side. It swings up and down with respect to the frame 320.
The region on the front side of the battery pack 400 exerts a function as a mass damper due to this swing, as in the first embodiment.
As described above, also in the third embodiment, the same effect as that of the above-mentioned first embodiment can be obtained.

(Modification example)
The present invention is not limited to the embodiments described above, and various modifications and changes can be made, and these are also within the technical scope of the present invention.
(1) The configuration of the vehicle and the battery pack mounting structure is not limited to each of the above-described embodiments, and can be appropriately changed.
For example, the vehicle shape, vehicle body structure, arrangement of structural members, and the like can be appropriately changed.
Further, in each embodiment, the vehicle is an engine-electric hybrid vehicle as an example, but the present invention can be applied to a pure EV or a fuel cell vehicle (FCV) equipped with a battery pack. ..
(2) In each embodiment, the battery pack is arranged on the rear side with respect to the antinode of the elastic vibration mode of the vehicle body, and the front end portion is configured to swing in the vertical direction. When arranged on the front side with respect to the antinode of the elastic vibration mode, the rear end portion can be configured to swing. In this case, the rear end portion of the battery pack and the antinode portion of the elastic vibration mode in the vehicle body can be connected by a center bracket.
(3) In each embodiment, the battery pack is placed above the floor surface of the vehicle body, but the present invention is not limited to this, and can be applied to a vehicle in which the battery pack is suspended under the floor. ..
(4) In the first and second embodiments, the battery pack is supported by the elastic battery bracket, and the positional relationship between the center position of the battery bracket and the center position of the battery pack or the center position of the reinforcing area is used. Therefore, the vertical support rigidity of the battery pack is different in the front-rear direction, but the method of making the support rigidity in the vertical direction of the battery pack different in the front-rear direction is not limited to this, and can be appropriately changed.
For example, the front and rear of the battery pack may be attached to the vehicle body by separate support members, and the rigidity of the front and rear support members may be different.
(5) In each embodiment, the center bracket is provided at one place in the central portion in the vehicle width direction, but the position where the center bracket is provided is not limited to the central portion in the vehicle width direction, but at other locations offset in the vehicle width direction. There may be.
Further, a plurality of center brackets may be provided.

1 Vehicle 100 Cabin FS Front Seat RS Rear Seat 110 Floor 120 A Pillar 121 Front Window Glass 130 B Pillar 140 C Pillar 150 D Pillar 160 Roof 170 Front Side Door 180 Rear Side Door 190 Rear Fender 200 Rear Gate 210 Rear Bumper Face 220 Engine Compartment 230 Front end module 250 Front bumper face 260 Front fender 270 Front wheel house 280 Rear wheel house 300 Rear floor part 310 Rear floor panel 320 Side frame 321 Front part 322 Middle part 323 Rear part 324 Mount part 330 1st cross member 340 2nd cross member FW Front wheel RW Rear wheel 400 Battery pack CG Center of gravity position 500 Battery bracket Cb Center position 510 Front 511 Fastening point 520 Middle part 530 Rear 531 Fastening point P1, P2, P3 Fixed point R Reinforcement area Cr Center position 600 Center bracket 700 Battery bracket

Claims (8)

The floor provided at the bottom of the car body and
It is a battery pack mounting structure including a battery pack that is configured to accommodate a battery cell in a container and is attached to the floor portion.
The vertical support rigidity of the battery pack with respect to the floor portion is made lower on one of the front side and the rear side than on the other side.
The battery pack mounting structure is characterized in that the side having the low support rigidity is arranged so as to be closer to the antinode portion of the elastic vibration mode of the floor portion with respect to the side having the high support rigidity. It is formed of an elastic material extending in the front-rear direction of the vehicle, and has a battery pack support member that is attached to the structural member of the vehicle body at the front end and the rear end and supports the battery pack.
The battery pack mounting according to claim 1, wherein the position of the center of gravity of the battery pack is arranged at a position far from the ventral portion of the elastic vibration mode with respect to the center position of the battery pack support member in the front-rear direction. structure. It is formed of an elastic material extending in the front-rear direction of the vehicle, and has a battery pack support member that is attached to the structural member of the vehicle body at the front end and the rear end and supports the battery pack.
With respect to the center position in the front-rear direction of the battery pack support member, the center position of the range in which the battery pack support member and the battery pack are coupled is arranged at a position far from the antinode portion of the elastic vibration mode. The battery pack mounting structure according to claim 1. It is provided with a pair of side frames that extend in the front-rear direction along the floor and are separated in the vehicle width direction.
The battery pack mounting structure according to claim 2 or 3, wherein the front end portion and the rear end portion of the battery pack support member are connected to the side frame. Reinforcing points provided at a position corresponding to or close to the abdominal part of the elastic vibration mode of the floor part and reinforced with respect to other parts of the floor part, and
The battery pack according to any one of claims 1 to 4, further comprising a connecting member for connecting the end portion of the battery pack on the side having a low support rigidity and the reinforcing portion. Mounting structure. The floor provided at the bottom of the car body and
It is a battery pack mounting structure including a battery pack that is configured to accommodate a battery cell in a container and is attached to the floor portion.
The battery pack is fixed to the floor portion on one of the front side and the rear side, and the other side can swing in the vertical direction with respect to the fixed portion with the floor portion due to the elastic deformation of the container.
A battery pack mounting structure characterized in that the swingable side is arranged so as to be close to the antinode portion of the elastic vibration mode of the floor portion with respect to the fixed portion. A reinforcing portion provided at a portion of the floor portion that coincides with or adjacent to the abdominal portion of the elastic vibration mode and is reinforced with respect to the other portion of the floor portion.
The battery pack mounting structure according to claim 6, further comprising a connecting member for connecting the swingable end of the battery pack and the reinforcing portion. The battery pack mounting structure according to claim 5 or 7, wherein the reinforcing portion is a cross member having a closed cross-sectional portion extending in the vehicle width direction along the floor portion.

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