JP7703906B2 - Body structure - Google Patents

Description

The present invention relates to the body structure of an electric vehicle.

For example, in the case of a car equipped with a traction motor, a battery unit is installed to supply power to the traction motor, and this battery unit has a large capacity to increase the driving range of the traction motor.

The battery unit of the electric vehicle disclosed in Patent Document 1 is mounted over a wide area under the floor. The front of the vehicle body is provided with a pair of left and right front side members extending in the fore-and-aft direction of the vehicle, and an under member extending in the fore-and-aft direction of the vehicle below the front side members. The battery unit under the floor also has a case main body. A pair of left and right front extensions extending forward of the vehicle are integrally formed on the front wall of the case main body by casting from the front wall. The rear end of the under member is connected to the front end of each front extension, and the front extensions and the under member are continuous in the fore-and-aft direction of the vehicle.

In Patent Document 1, the under-member is configured to be more easily deformed than the front extension, so that when the vehicle collides head-on with an obstacle, the under-member deforms first to absorb the collision load. Any collision load that cannot be absorbed by the deformation of the under-member is absorbed by the deformation of the front extension of the case main body. In other words, in Patent Document 1, the under-member and the front extension of the case main body are actively deformed as shock absorbing members during a frontal collision, absorbing the collision load in two stages and suppressing deformation of the case main body.

JP 2018-158688 A

As described above, in Patent Document 1, by combining an under-member that deforms under a relatively small load with a front extension that deforms under a relatively large load in the fore-and-aft direction of the vehicle, the collision load is prevented from being transmitted to the case main body, thereby suppressing deformation of the case main body.

However, there is a demand for further improvements in collision safety for automobiles. In particular, when a large collision load is input to the vehicle body, it is necessary not only to suppress deformation of the cabin caused by the collision load, but also to protect the large-capacity battery cells installed in electric vehicles. On the other hand, there is also a strong demand for lighter vehicle bodies, so the challenge is how to achieve both further improvements in collision safety and lighter vehicle bodies.

In this regard, in the case of Patent Document 1, the under-member and the front extension are deformed in the lower part of the vehicle body to absorb the collision load, so in order to deal with the input of a larger collision load, the strength of the front side member located above the under-member must be increased, which raises concerns that the vehicle weight will increase. Furthermore, if the strength of the front side member is increased, a concentrated load will be input locally to the vehicle body from the rear end of the front side member, so reinforcement of that part will also be required, which may lead to a further increase in the vehicle weight.

The present invention was made in consideration of these points, and its purpose is to distribute and transmit the collision load in the fore-and-aft direction of the vehicle to the vehicle body and the battery case, thereby optimizing the strength of each member that makes up the body and realizing a reduction in the overall weight of the vehicle.

In order to achieve the above object, in a first aspect of the present disclosure, a vehicle body structure of an electric vehicle is provided with a driving motor, and a battery case housing a battery that supplies power to the driving motor is disposed below a floor panel. The vehicle body structure includes a pair of left and right side frames disposed to extend in the vehicle longitudinal direction above and to one side of the floor panel in the vehicle longitudinal direction, a pair of left and right side sills disposed to extend in the vehicle longitudinal direction at both ends of the floor panel in the vehicle width direction, a floor reinforcement that connects the side frames and the side sills and transmits a load from the side frames to the side sills, a frame member extending from the battery case below the side frame in one direction in the vehicle longitudinal direction, and an outer connection portion that extends from a midway portion of the frame member in the vehicle longitudinal direction toward the side sill and is connected to the battery case. The floor reinforcement and the outer connection portion are spaced apart from each other in the vertical direction.

According to this configuration, when the side frame and the frame member are provided at the front of the vehicle body, the collision load during a frontal collision is input to the side frame and the frame member. The collision load input to the side frame is transmitted to the side sill via the floor reinforcement. In addition, since the outer connection part is connected to the battery case, the collision load input to the frame member is transmitted to the battery case and absorbed. Furthermore, since the outer connection part extends toward the side sill side, the collision load can also be applied toward the side sill side via the outer connection part. At this time, since the floor reinforcement and the outer connection part are separated in the vertical direction, the route of the collision load transmitted from the side frame to the side sill and the route of the collision load acting from the frame member toward the side sill side are different routes, and therefore the collision load is transmitted to the side sill via multiple routes. Since this side sill is a particularly high-rigidity member among the members that generally constitute the vehicle body, the collision load can be absorbed by the side sill. Therefore, it is possible to optimize the strength of the side frame and the strength of the members near the rear end of the side frame.

When the side frame and frame member are provided at the rear of the vehicle body, the collision load during a rear-end collision is transmitted to the side sill via multiple routes, so the amount of collision load absorbed by the side sill can be increased, just as in the case of a frontal collision. This makes it possible to optimize the strength of each member that makes up the vehicle body.

In a second aspect of the present disclosure, the portion of the floor reinforcement on the side sill side and the portion of the outer connection portion on the battery case side are positioned so as to overlap each other in a plan view.

In other words, the portion of the floor reinforcement on the side sill side is the portion that is connected to the side sill, and is therefore positioned adjacent to the side sill. On the other hand, the outer connection portion is a member that is connected to the battery case, and is therefore spaced apart from the side sill. However, the fact that the portion of the outer connection portion on the battery case side overlaps with the portion of the floor reinforcement on the side sill side in a plan view means that the portion of the outer connection portion on the battery case side can be brought closer to the side sill. This ensures that the collision load is applied toward the side sill via the outer connection portion.

In a third aspect of the present disclosure, an inner reinforcement extending in the vehicle front-rear direction is provided inside the side sill.

This configuration further increases the rigidity of the side sill, further improving the side sill's ability to absorb collision loads transmitted from both the floor reinforcement and the outer connection portion.

In a fourth aspect of the present disclosure, an inner connection portion extends from a midway portion of the frame member in the vehicle front-rear direction toward the center of the battery case in the vehicle width direction and is connected to the battery case. A central member extending in the vehicle front-rear direction is provided in the center of the battery case in the vehicle width direction.

With this configuration, the collision load input to the frame member is transferred to and absorbed by the battery case because the inner connection portion is connected to the battery case. Because the inner connection portion extends toward the center of the battery case in the vehicle width direction, the collision load is transferred to the center of the battery case in the vehicle width direction or its vicinity. At this time, because there is a central member extending in the vehicle front-rear direction at the center of the battery case in the vehicle width direction, the collision load can also be absorbed by the central member.

In a fifth aspect of the present disclosure, the frame member is disposed inward in the vehicle width direction from the side frame.

With this configuration, the collision load is transmitted to the side sill via multiple routes, via the side frame located relatively outboard in the vehicle width direction and the frame member located inboard in the vehicle width direction.

In a sixth aspect of the present disclosure, a pair of left and right hinge pillars extend upward from the pair of left and right side sills. The portion of the floor reinforcement on the side sill side and the base end of the hinge pillar are disposed at the same position in the vehicle fore-and-aft direction.

In other words, the area of the side sill near the base end of the hinge pillar is particularly rigid, and by connecting the floor reinforcement to this particularly rigid area, the side sill can efficiently absorb collision loads.

In a seventh aspect of the present disclosure, the floor reinforcement is formed to extend in the vehicle front-rear direction along the upper surface of the floor panel, and is attached to the upper surface of the floor panel to form a closed cross section together with the floor panel.

This configuration further enhances the reinforcing effect of the floor reinforcement and ensures that collision loads are transmitted to the side sill.

As explained above, the vehicle is equipped with a floor reinforcement that transmits the load from the side frame to the side sill, a frame member that extends in the fore-and-aft direction from the battery case, and an outer connection portion that extends from the midway portion of the frame member in the fore-and-aft direction toward the side sill, so that the collision load can be distributed and transmitted to the side sill of the vehicle body and the battery case. This optimizes the strength of each member that constitutes the vehicle body, achieving a reduction in the weight of the entire vehicle.

1 is a side view of an electric vehicle according to an embodiment of the present invention. FIG. 2 is a side view showing the electric vehicle separated into a lower structure and an upper structure. FIG. 2 is a perspective view of the lower structure seen from above. FIG. FIG. 5 is a view equivalent to FIG. 4 of a lower structure equipped with a small battery case. FIG. 13 is a left side view of the lower structure when the height of the front central member is increased. FIG. 2 is a cross-sectional view of the electric vehicle at the center in the left-right direction. 1 is a cross-sectional view of an electric vehicle seen from the front. FIG. 2 is a cross-sectional view of the electric vehicle as seen from the rear. FIG. 2 is a front perspective view showing a cross section passing through the front seat portion of the electric vehicle. 2 is a diagram showing a floor panel, a front seat, a front seat occupant, and a battery unit. FIG. FIG. 11 is an enlarged front view of part C in FIG. 10 . FIG. 2 is a perspective view from below showing a cross section of the rear part of the electric vehicle. 13A and 13B are diagrams illustrating a floor panel and a battery unit according to a modified example.

The following describes in detail an embodiment of the present invention with reference to the drawings. Note that the following description of the preferred embodiment is essentially merely an example and is not intended to limit the present invention, its applications, or its uses.

Figure 1 is a left side view of an electric vehicle 1 equipped with a vehicle body structure A according to an embodiment of the present invention. As shown in Figure 2, this electric vehicle 1 is equipped with a lower structure 2 and an upper structure 3, and the lower structure 2 and the upper structure 3 constitute the vehicle body structure A. Figure 2 shows the vehicle with the doors, hood, front fenders, windshield, bumpers, front and rear lighting devices, etc. removed. In the explanation of this embodiment, the front side of the vehicle will be simply referred to as "front", the rear side of the vehicle will be simply referred to as "rear", the right side of the vehicle will be simply referred to as "right", and the left side of the vehicle will be simply referred to as "left". The left-right direction of the vehicle is the vehicle width direction.

As shown in FIG. 1, the electric vehicle 1 is a passenger vehicle. As shown in FIG. 2, a front seat S1 is provided at the front of the passenger compartment R1, which is the living space for the occupants, and a rear seat S2 is provided behind the front seat S1 in the passenger compartment R1. A luggage compartment R2 is provided behind the rear seat S2 as necessary. The passenger compartment R1 and the luggage compartment R2 are provided in the upper structure 3. Note that only the front seat S1 may be provided in the passenger compartment R, or a third row seat (not shown) may be provided behind the rear seat S2.

On the other hand, the space in front of the vehicle interior R1, which is the front part of the electric vehicle 1, can be, for example, a power room R3. That is, the vehicle body structure A includes a driving motor M that generates power for driving the drive wheels, and a battery case 10 that houses a battery B (shown only in FIG. 4) that supplies power to the driving motor M. The power train PT is composed of only the driving motor M, or the driving motor M together with a reduction gear, a transmission, etc. In FIG. 1 and FIG. 2, the power train PT is shown only in the power room R3, but the power train PT may also be provided in the lower space R4 of the luggage compartment R2 (the rear power train is not shown). When the power train PT is provided only in the power room R3, only the front wheels F are driven. When the power train PT is provided in the lower space R4, only the rear wheels R are driven. In this case, the power room R3 can be used as a luggage space, etc. Also, when the power train PT is provided in both the power room R3 and the lower space R4, it becomes a four-wheel drive vehicle. The battery case 10 is disposed below the floor panel 70, which will be described later.

As shown in Figures 3 and 4, the lower structure 2 includes a battery case 10, a front frame member 11 that extends forward in front of the battery case 10, and a rear frame member 12 that extends rearward behind the battery case 10. In Figure 3, the left front wheel F, rear wheel R, suspension arm, etc. are omitted.

In the case of a typical electric vehicle, the battery case is often separate from the vehicle body and is detachably attached under the floor, but in this embodiment, not only is the battery case 10 provided, but the front frame member 11 and rear frame member 12 are integrated into the battery case 10, and the front frame member 11 and rear frame member 12 are also detachably attached to the upper structure 3 together with the battery case 10.

Specifically, the electric vehicle 1 of this embodiment is configured to be separable into a lower structure 2 having a battery case 10 and an upper structure 3 that forms the vehicle interior R1 and luggage compartment R2. Being separable into upper and lower parts means that the lower structure 2 is integrated with the upper structure 3 using fastening members such as bolts, nuts, and screws, without using welding, adhesives, etc. This allows the lower structure 2 to be separated from the upper structure 3 as necessary when maintenance or repair is performed after the electric vehicle 1 is delivered to the user, improving maintainability.

Here, a ladder frame type vehicle body structure is known as an automobile body structure. In the case of a ladder frame type vehicle body structure, it can be separated into a ladder frame and a cabin from above and below, but since the ladder frame extends continuously in the fore-and-aft direction, it mainly bears the collision load in the event of a frontal collision and a rearward collision. In the event of a side collision, the ladder frame only bears the collision load auxiliaryally, and it is the cabin that bears the main collision load. In this way, in a ladder frame type vehicle body structure, the components that bear the collision load in the event of a frontal collision and a rearward collision and in the event of a side collision are usually separate.

In contrast, in the case of the electric vehicle 1 of this embodiment, the lower structure 2 and the upper structure 3 having the frame members 11, 12 are separable, but in the case of both a frontal collision, a rear collision, and a side collision, the collision load is received by the lower structure 2 and the upper structure 3, and the collision load is distributed and absorbed by both structures 2, 3, which is a significant difference in technical concept from the conventional ladder frame type vehicle body structure. The structure and effects of the lower structure 2 and the upper structure 3 will be explained below.

(Lower structure)
First, the lower structure 2 will be described. As shown in Figures 3 and 4, in addition to the battery case 10, the front frame 11, and the rear frame 12, the lower structure 2 also includes a power train PT, front wheels F, rear wheels R, a front suspension device 13, and a rear suspension device 14. There is no particular restriction on the type of the front suspension device 13 and the rear suspension device 14.

The battery case 10 is a large case formed under the floor panel 70 described below, extending from near the left end to near the right end of the floor panel 70 and from near the front end to near the rear end of the floor panel 70. By providing the battery case 10 over a wide area under the floor panel 70 in this way, it becomes possible to mount a large-capacity battery B in the electric vehicle 1 as shown in FIG. 4. The battery B may be, for example, a lithium-ion battery or an all-solid-state battery, or may be another secondary battery. The battery B may also be a so-called battery cell, or a battery pack containing multiple battery cells.

The battery case 10 includes a left side member 20, a right side member 21, a front end member 22, a rear end member 23, and a bottom plate 24. The left side member 20, the right side member 21, the front end member 22, and the rear end member 23 are made of, for example, an aluminum alloy extrusion material, but may also be made of aluminum alloy plate material or press-formed steel plate material. The bottom plate 24 may also be made of an extrusion material. In the following description, "extrusion material" refers to an aluminum alloy extrusion material, and "press-formed material" refers to aluminum alloy plate material or press-formed steel plate material. Each member may also be made of, for example, a casting.

The left side member 20, the right side member 21, the front end member 22, and the rear end member 23 all have a rectangular cross-sectional shape in a direction perpendicular to the longitudinal direction. In addition, the left side member 20, the right side member 21, the front end member 22, and the rear end member 23 are all positioned at the same height and extend approximately horizontally.

The left side member 20 is provided at the left end of the battery case 1 and extends in the front-rear direction. The right side member 21 is provided at the right end of the battery case 1 and extends in the front-rear direction. The front end member 22 is provided at the front end of the battery case 1 and extends in the left-right direction. The left end of the front end member 22 is connected to the front end of the left side member 20, and the right end of the front end member 22 is connected to the front end of the right side member 21. The rear end member 23 is provided at the rear end of the battery case 1 and extends in the left-right direction. The left end of the rear end member 23 is connected to the rear end of the left side member 20, and the right end of the rear end member 23 is connected to the rear end of the right side member 21. The bottom plate 24 extends approximately horizontally and is fixed to the lower surfaces of the left side member 20, the right side member 21, the front end member 22 and the rear end member 23. Therefore, the left side member 20, the right side member 21, the front end member 22, the rear end member 23, and the bottom plate 24 define a battery storage space S (shown in FIG. 3) that stores the battery B.

The size of the battery storage space S can be changed according to the capacity of the battery B to be mounted. The size of the battery storage space S can be easily changed by changing the length of the left side member 20, the right side member 21, the front end member 22, and the rear end member 23 and the shape of the bottom plate 24. For example, in the case of a small vehicle with a short wheelbase and narrow tread, the left side member 20, the right side member 21, the front end member 22, and the rear end member 23 are shortened and the shape of the bottom plate 24 is accordingly made smaller, so that the battery storage space S is smaller according to the small vehicle (see FIG. 5). On the other hand, in the case of a large vehicle, the left side member 20, the right side member 21, the front end member 22, and the rear end member 23 are lengthened and the shape of the bottom plate 24 is accordingly made larger, so that the battery storage space S is larger according to the large vehicle. If the left side member 20, the right side member 21, the front end member 22, and the rear end member 23 are made of extruded material, the length can be easily changed. In addition, the bottom plate 24 can also be made of extruded material, so that the shape can be easily changed.

The upper part of the battery storage space S may be closed by a lid (not shown) or by a floor panel 70 (described later). In addition to the battery B, the battery storage space S may also be provided with a cooling device for cooling the battery B and a heating device for heating the battery B (temperature control device). Furthermore, the power of the battery B is supplied to the driving motor M via a control device (not shown). Furthermore, the battery B can be charged via a charging socket (not shown).

As shown in FIG. 3, inside the battery case 10, first to third battery side cross members 25A, 25B, 25C are provided as reinforcing members extending in the left-right direction. The first to third battery side cross members 25A, 25B, 25C all have the same height, which is approximately the same as the height of the left side member 20, etc. The battery side cross members 25A, 25B, 25C may be made of an extruded material or a press-molded material. In this embodiment, three battery side cross members 25A, 25B, 25C are provided, but the number of battery side cross members 25A, 25B, 25C can be increased or decreased depending on the front-rear dimension of the battery case 10.

The first to third battery side cross members 25A, 25B, 25C are spaced apart from each other in the front-to-rear direction, with the first battery side cross member 25A positioned at the front and the third battery side cross member 25C positioned at the rear. The lower portion of each battery side cross member 25A, 25B, 25C is fixed to the upper surface of the bottom plate 24. The left end portion of each battery side cross member 25A, 25B, 25C is fixed to the inner surface (right side surface) of the left side member 20, and the right end portion of each battery side cross member 25A, 25B, 25C is fixed to the inner surface (left side surface) of the right side member 21. In other words, the battery side cross members 25A, 25B, 25C are members that connect the left side member 20 and the right side member 21.

Figure 5 above shows an example of a lower structure 2 equipped with a small battery case 10 that is set to have a shorter front-to-rear dimension than the battery case 10 shown in Figure 4, but in the example shown in Figure 5, due to the shorter front-to-rear dimension, the third battery side cross member 25C is omitted. Conversely, although not shown, a fourth battery side cross member can also be provided.

A front central member (front reinforcing member) 26 and first to third rear central members (rear reinforcing members) 27 to 29 are provided inside the battery case 10 as reinforcing members extending in the front-rear direction. The front central member 26 and the first to third rear central members 27 to 29 are disposed at approximately the same height and are provided in the center of the battery case 10 in the left-right direction. The lower ends of the front central member 26 and the first to third rear central members 27 to 29 are attached to the upper surface of the bottom plate 24.

The front central member 26 is disposed between the front end member 22 and the first battery side cross member 25A, with the front end of the front central member 26 fixed to the left-right center of the front end member 22 and the rear end of the front central member 26 fixed to the left-right center of the first battery side cross member 25A. Therefore, the front end member 22 is a member that extends to connect the front ends of the left side member 20 and the right side member 21 to the front end of the front central member 26.

The first rear central member 27 is disposed between the first battery side cross member 25A and the second battery side cross member 25B, with the front end of the first rear central member 27 fixed to the left-right center of the first battery side cross member 25A and the rear end of the first rear central member 27 fixed to the left-right center of the second battery side cross member 25B. The second rear central member 28 is disposed between the second battery side cross member 25B and the third battery side cross member 25C, with the front end of the second rear central member 28 fixed to the left-right center of the second battery side cross member 25B and the rear end of the second rear central member 28 fixed to the left-right center of the third battery side cross member 25C. In addition, the third rear central member 29 is disposed between the third battery side cross member 25C and the rear end member 23, with the front end of the third rear central member 29 fixed to the left-right center of the third battery side cross member 25C, and the rear end of the third rear central member 29 fixed to the left-right center of the rear end member 23. Therefore, the first to third battery side cross members 25A, 25B, 25C, the front central member 26, and the first to third rear central members 27 to 29 are arranged in a lattice pattern inside the battery case 10 and connected to each other, further enhancing the reinforcing effect of the battery case 10.

When imaginary straight lines extending in the front-to-rear direction in plan view are assumed, the front central member 26 and the first to third rear central members 27-29 are positioned in the left-to-right direction so that they are located on the imaginary straight line. In other words, the first to third rear central members 27-29 are positioned on an imaginary extension line to the rear of the front central member 26. The front central member 26 and the first to third rear central members 27-29 may be configured as a single member that is continuous in the front-to-rear direction.

Figure 6 shows an example in which the height of the front central member 26 is made higher than the height of the first to third rear central members 27 to 29 (not shown in Figure 6). As will be described in detail later, the floor panel 70 of the upper structure 3 has the front floor portion 70a located higher than the rear floor portion 70b. The front central member 26 is provided below the front floor portion 70a, and the first to third rear central members 27 to 29 are provided below the rear floor portion 70b. The upper end of the front central member 26 is formed to be located higher than the rear floor portion 70b. In other words, the upper ends of the first to third rear central members 27 to 29 are located lower than the upper end of the front central member 26 to correspond to the relatively low rear floor portion 70b. In this case, the first battery side cross member 25A may be provided below the front floor portion 70a, in which case the upper end of the first battery side cross member 25A can be formed to be located above the second and third battery side cross members 25B and 25C.

As shown in Figures 3 and 4, a pair of left and right front frame members 11 are provided, and extend substantially horizontally in a straight line below the left and right front side frames 72 described below. Each front frame member 11 can be made of, for example, an extruded material or a press-molded material. In this embodiment, each front frame member 11 is made of an extruded material, so that the cross-sectional shape in the direction perpendicular to the front-to-rear direction is substantially the same from the front end to the rear end.

The left front frame member 11 is connected to a portion of the front end member 22 constituting the front of the battery case 10 that is to the left of the center in the left-right direction, and this connection portion is located to the right of the left side member 20 of the battery case 10. The right front frame member 11 is connected to a portion of the front end member 22 that is to the right of the center in the left-right direction, and this connection portion is located to the left of the right side member 21 of the battery case 10. This provides a predetermined distance between the left and right front frame members 11, making it possible to position the lower part of the powertrain PT between the left and right front frame members 11. The distance between the left and right front frame members 11 is set narrower than the distance between the left side member 20 and right side member 21 of the battery case 10.

The left and right front frame members 11 are approximately the same height. In addition, the left and right front frame members 11, the front central member 26 of the battery case 10, the left side member 20, and the right side member 21 are disposed at approximately the same height.

The battery case 10 side (rear side) of each front frame member 11 is connected to the battery case 10 at multiple locations spaced apart from each other in the left-right direction. Specifically, the rear end of the right front frame member 11 is connected to the front end member 22, and a location further forward than the rear end of the front frame member 11 is connected to the front end member 22 by an outer connection portion (one connection portion) 30 and an inner connection portion (the other connection portion) 31. This allows the collision load input to the front frame member 11 during a frontal collision to be distributed and transmitted to multiple locations of the battery case 10.

The outer connection part 30 and the inner connection part 31 are made of high-rigidity materials such as extrusion materials or press-molded materials, and are tubular, plate-like, or columnar. In a plan view, the width of the outer connection part 30 and the inner connection part 31 is set to be wider than the width of the front frame member 11, which further enhances the dispersion effect of the collision load. The width of the outer connection part 30 and the inner connection part 31 may be the same as the width of the front frame member 11, or may be narrower than the width of the front frame member 11.

The right outer connection part 30 is provided to the right of the right front frame member 11 (outside in the vehicle width direction) at approximately the same height as the front frame member 11, and is inclined in the front-rear direction in a plan view so that it is positioned to the right as it approaches the rear end. The front end of the right outer connection part 30 is connected to a portion between the front-rear center and the rear end of the front frame member 11 (midway in the front-rear direction). The outer connection part 30 extends from the connection portion with the front frame member 11 to the right and rear, that is, toward the side sill 73 (described later) of the upper structure 3. The rear end of the right outer connection part 30 is connected to a portion of the front end member 22 that is spaced to the right from the rear end of the front frame member 11. The connection structure between the outer connection part 30 and the front frame member 11 and the connection structure between the outer connection part 30 and the front end member 22 may be a connection structure using fastening members such as bolts and nuts, or a connection structure using welding, adhesives, etc.

The right inner connection part 31 is provided to the left of the right front frame member 11 (inner in the vehicle width direction) at approximately the same height as the front frame member 11, and is inclined in the front-rear direction in a plan view so that it is positioned more to the left as it approaches the rear end. The front end of the right inner connection part 31 is connected to a portion between the front-rear center and the rear end of the front frame member 11 (mid-way in the front-rear direction). The right inner connection part 31 extends leftward and rearward from the connection portion with the front frame member 11, that is, toward the left-right center of the battery case 10. The rear end of the inner connection part 31 is connected to a portion of the front end member 22 that is spaced leftward from the rear end of the front frame member 11. The connection structure between the inner connection part 31 and the front frame member 11 and the connection structure between the inner connection part 31 and the front end member 22 can be the same as the connection structure of the outer connection part 30.

In this embodiment, the right front frame member 11 is connected to the front end member 22 at three points spaced apart from each other in the left-right direction, but this is not limited to the above. One of the outer connection part 30 and the inner connection part 31 may be omitted and the front frame member 11 may be connected to the front end member 22 at two points, or the rear end of the front frame member 11 may not be connected to the front end member 22 and may be connected to the front end member 22 only by the outer connection part 30 and the inner connection part 31.

The left front frame member 11 can also be connected to the front end member 22 in the same manner as the right front frame member 11. The connection structure of the left front frame member 11 can be a symmetrical structure to that of the right front frame member 11.

As shown in FIG. 3, an intermediate connecting member 49, a front connecting member 50, and a rear connecting member 51 are provided in front of the battery case 10 of the lower structure 2 with a gap in the front-rear direction. The front connecting member 50 extends in the vehicle width direction from the front of the left front frame member 11 to the front of the right front frame member 11, and connects the left front frame member 11 and the right front frame member 11. The rear connecting member 51 extends in the vehicle width direction from the rear of the left front frame member 11 to the rear of the right front frame member 11, and connects the left front frame member 11 and the right front frame member 11. The front connecting member 50 and the rear connecting member 51 are made of, for example, an extrusion material or a press-molded material. By connecting the left and right front frame members 11 with the front connecting member 50 and the rear connecting member 51, a frame structure with a frame shape is formed in a plan view.

The intermediate connecting member 49 is provided between the front connecting member 50 and the rear connecting member 51, and extends in the vehicle width direction from the front of the left front frame member 11 to the front of the right front frame member 11, connecting the left front frame member 11 and the right front frame member 11. The intermediate connecting member 49 may be provided as needed, or may be omitted.

The front connecting member 50 extends from the top surface of the left front frame member 11 to the top surface of the right front frame member 11 and is disposed so as to protrude above the top surfaces of both front frame members 11. Meanwhile, the rear connecting member 51 is disposed between the left and right front frame members 11, with the left end of the rear connecting member 51 connected to the side surface of the left front frame member 11 and the right end of the rear connecting member 51 connected to the side surface of the right front frame member 11. The front connecting member 50 and the rear connecting member 51 may be fixed to the front frame member 11 by a fastening member, or may be fixed by welding, adhesive, etc.

The longitudinal dimensions of the front connecting member 50 and the rear connecting member 51 are set to be longer than the lateral dimension of the front frame member 11. This increases the connection strength of the front frame member 11 by both connecting members 50, 51.

As shown in FIG. 4, the powertrain PT is disposed rearward of the front connecting member 50. Specifically, in a plan view, the powertrain PT is disposed between the front connecting member 50 and the rear connecting member 51. Drive shafts 52 are provided on the left and right of the lower structure 2 to transmit the output of the powertrain PT to the left and right front wheels F, respectively.

The left and right suspension arms 13a, which form part of the front suspension device 13, are supported by the left and right front frame members 11 via brackets 13b so that they can swing freely. The brackets 13b are provided at the connection points between the left and right front frame members 11 and the rear connecting member 51.

The lower structure 2 has two left side connecting parts 53, 54 that connect the left front frame member 11 to the left front side frame 72 (described later) and are provided at intervals from each other in the front-rear direction, and two right side connecting parts 55, 56 that connect the right front frame member 11 to the right front side frame 72 (described later) and are provided at intervals from each other in the front-rear direction. The left side connecting parts 53, 54 and the right side connecting parts 55, 56 can be made of a plate material, a cylindrical member, a columnar member, or the like that extends in the vertical direction. In this embodiment, the left side connecting parts 53, 54 and the right side connecting parts 55, 56 are made of press-molded material, but they may be made of extruded material, or the like. In addition, the number of the left side connecting parts 53, 54 is not limited to two, and three or more may be provided at intervals from each other in the front-rear direction. The same applies to the right side connecting parts 55, 56.

The front left connecting part 53 is provided at the connection site of the front connecting member 50 with the left front frame member 11. Specifically, the front part of the left front frame member 11 and the left end of the front connecting member 50 are arranged overlapping in the vertical direction, and the left end of the front connecting member 50 is connected to the front part of the left front frame member 11, so that the connection site is formed by the left end of the front connecting member 50. The lower end of the front left connecting part 53 is attached to the left end of the front connecting member 50.

The front right-side connecting part 55 is provided at the connection site of the front connecting member 50 with the right front frame member 11. Specifically, the front part of the right front frame member 11 and the right end part of the front connecting member 50 are arranged overlapping in the vertical direction, and the right end part of the front connecting member 50 is connected to the front part of the right front frame member 11, so that the connection site is formed by the right end part of the front connecting member 50. The lower end part of the front right-side connecting part 55 is attached to the right end part of the front connecting member 50.

The rear left-side connecting part 54 is provided at the connection site with the intermediate connecting member 49 in the left front frame member 11. The lower end of the rear left-side connecting part 54 is attached to the left front frame member 11 and is located rearward of the left drive shaft 52. The rear right-side connecting part 56 is provided at the connection site with the intermediate connecting member 49 in the right front frame member 11. The lower end of the rear right-side connecting part 56 is attached to the right front frame member 11 and is located rearward of the right drive shaft 52. This makes it possible to widen the distance between the front and rear left-side connecting parts 53, 54 and the distance between the front and rear right-side connecting parts 55, 56.

The right front frame member 11 is disposed to the left (inner in the vehicle width direction) of the right front side frame 72 shown in FIG. 8, and the left front frame member 11 is disposed to the right (inner in the vehicle width direction) of the left front side frame 72 shown in FIG. 2. This makes the distance between the left and right front side frames 72 wider than the distance between the left and right front frame members 11. A powertrain PT including a driving motor M is mounted between the left and right front side frames 72.

As shown in FIG. 3, the right side connectors 55, 56 are formed so that they are positioned further to the right (outside in the vehicle width direction) as they move upward. This is because the right front side frame 72 is positioned above the right front frame member 11 and to the right of the front frame member 11. Similarly, the left side connectors 53, 54 are formed so that they are positioned further to the left (outside in the vehicle width direction) as they move upward.

The rear frame members 12 are provided in a pair on the left and right sides, similar to the front frame members 11, and extend rearward in a straight line substantially horizontally. Each rear frame member 12 can be made of, for example, an extruded material or a press-molded material. In this embodiment, each rear frame member 12 is made of an extruded material.

The left rear frame member 12 is connected to a portion of the rear end member 23 that constitutes the rear of the battery case 10 that is to the left of the center in the left-right direction, and this connection portion is located to the right of the left side member 20 of the battery case 10. The right rear frame member 12 is connected to a portion of the rear end member 23 that is to the right of the center in the left-right direction, and this connection portion is located to the left of the right side member 21 of the battery case 10. The connection structure of the rear frame member 12 to the rear end member 23 can be the same as the connection structure of the front end member 22 of the front frame member 11 described above.

In the embodiment shown in FIG. 5, the front ends of the left and right rear frame members 12 are connected to the rear end member 23, and the middle portion of the rear frame members 12 in the fore-aft direction is connected to the rear end member 23 by a connecting member 60. As a result, the battery case 10 side of the rear frame members 12 is connected to the battery case 10 at multiple locations spaced apart from each other in the left-right direction.

The left and right suspension arms 14a, which form part of the rear suspension device 14, are supported to be able to swing freely on the left and right rear frame members 12 via brackets 14b.

(superstructure)
Next, the upper structure 3 will be described. As shown in Figures 7 to 10, the upper structure 3 includes a floor panel 70, a dash panel 71, a pair of left and right front side frames 72, and a pair of left and right side sills 73. Figures 7 to 10 show a state in which the doors, bonnet hood, front fenders, windshield, bumpers, front and rear lighting devices, some of the seats, interior materials, etc. have been removed.

The floor panel 70 constitutes the floor surface of the vehicle compartment R1 and is made of a steel plate or the like that extends in the front-rear direction as well as the left-right direction. The space above the floor panel 70 forms the vehicle compartment R1. A roof 80 is provided at the top of the vehicle compartment R1. As shown in FIG. 2, a front opening 3a and a rear opening 3b are formed on the left side of the upper structure 3. As shown in FIG. 1, the front opening 3a and the rear opening 3b can be opened and closed by a front door 81 and a rear door 82, respectively. Although not shown, a front door and a rear door are also provided on the right side of the upper structure 3 so as to be opened and closed.

The dash panel 71 is a member for separating the passenger compartment R1 and the power compartment R3 in the front-rear direction. The dash panel 71 is made of, for example, a steel plate and extends in the left-right direction as well as the up-down direction. As shown in Figures 7 to 9, front wheel house sections 85 (only the right one is shown in Figures 7 to 9) for accommodating the left and right front wheels F are provided on both the left and right sides of the front part of the upper structure 3. The left end of the dash panel 71 is connected to the left front wheel house section 85 (shown in Figure 2), and the right end of the dash panel 71 is connected to the right front wheel house section 85 (shown in Figures 7 to 9).

As shown in FIG. 11, the floor panel 70 has a front floor portion 70a and a rear floor portion 70b. Furthermore, as shown in FIG. 10, the floor panel 70 also has a kick-up portion 70c at its rear. The front floor portion 70a, the rear floor portion 70b, and the kick-up portion 70c may be integrally formed from a single plate material, or may be formed from different plate materials. If they are formed from different plate materials, a single floor panel 70 can be constructed by joining multiple plate materials.

As shown in FIG. 11, the front floor section 70a constitutes the front portion of the floor panel 70, and is inclined or curved so that it is positioned higher as it moves toward the front. The front end of the front floor section 70a is connected to the lower end of the dash panel 71. Therefore, the floor panel 70 is provided so as to extend rearward from the lower end of the dash panel 71.

The rear floor section 70b is formed to extend rearward from the rear end of the front floor section 70a, and constitutes the middle section of the floor panel 70 in the fore-aft direction. The front section of the battery case 10 of the lower structure 2 is located directly below the front floor section 70a, and the rear section of the battery case 10 is located directly below the rear floor section 70b. Therefore, the battery case 10 is formed to extend from below the front floor section 70a to below the rear floor section 70b, which allows the battery B to be mounted in most of the area below the floor panel 70.

The front-rear middle portion of the floor panel 70 is lower than the front floor portion 70a. In other words, the front floor portion 70a is provided in front of the rear floor portion 70b and is located higher than the rear floor portion 70b. At least a part of a seat fixing portion 100 for fixing the front seat S1 is attached to the front portion of the rear floor portion 70b. The seat fixing portion 100 is composed of, for example, a bracket. At least the rear portion of the seat fixing portion 100 needs to be attached to the rear floor portion 70b, and the entire seat fixing portion 100 may be attached to the rear floor portion 70b. By attaching at least the rear portion of the seat fixing portion 100 to the rear floor portion 70b, the front seat S1 can be laid out low, so that the hip point of the front seat occupant P can be lowered, and as a result, the head space of the front seat occupant P is increased, improving livability. Furthermore, lowering the hip point means that the seating position of the front seat occupant P is lowered, which lowers the center of gravity of the vehicle when in the passenger seat. In this embodiment, the entire seat fixing part 100 is attached to the rear floor part 70b, so the front seat S1 can be laid out even lower.

When a driver, acting as a front seat occupant P, sits on the front seat S1, the heel P1 of the front seat occupant P is placed on the front floor section 70a. Because the front floor section 70a on which the heel P1 is placed is positioned higher than the rear floor section 70b, the heel P1 is placed in a higher position than in the operating posture of a typical automobile (an automobile in which the front and rear floor sections are at the same height). With this layout, the upper leg P2 and lower leg P3 of the front seat occupant P are placed in a posture with a large gap between them. In FIG. 11, the reference numeral 101 indicates the center line of the upper leg P2, and the reference numeral 102 indicates the center line of the lower leg P3. The difference in height between the front floor section 70a and the rear floor section 70b is set so that the angle between the center line 101 and the center line 102 (the opening angle α between the upper leg P2 and the lower leg P3) is in the range of 125° to 150°.

By setting the height difference in this way, the angle between the lower leg P3 and the front floor part 70a (angle β between the center line 101 and the front floor part 70a) is reduced, so the vertical component of force input to the heel P1 during pedal operation is reduced, improving the operability of the brake pedal 103. To be more specific, when the front seat occupant P depresses the brake pedal 103, the heel P1 applies a diagonally downward force F to the front floor part 70a. If this force F is divided into a vertical force and a horizontal force, they are force F1 and force F2, respectively. As described above, since the angle β is reduced, the vertical component of force F1 input from the heel P1 is reduced. This allows, for example, a change of foot from the brake pedal 103 to the accelerator pedal (not shown) or vice versa to be performed quickly and accurately, improving the operability of the pedal.

In addition, rear seat passengers may place their feet on the rear floor section 70b. Because the rear floor section 70b is lower than the front floor section 70a, the foot space for rear seat passengers is increased, improving the livability of the rear seat passengers.

As shown in Figures 7 to 9, the kick-up portion 70c constitutes the rear portion of the floor panel 70 and is connected to the rear end of the rear floor portion 70b. The kick-up portion 70c is located higher than the rear floor portion 70b, and a vertical plate portion 70d extending in the vertical direction is formed between the kick-up portion 70c and the rear floor portion 70b. The height of the kick-up portion 70c is set higher than that of the front floor portion 70a. The rear seat S2 (shown in Figure 2) is attached to the upper surface of the kick-up portion 70c. A battery B may be disposed below the kick-up portion 70c, or a control device for the electric vehicle 1 (not shown) may be disposed below the kick-up portion 70c.

A floor-side cross member 110 is attached to the floor panel 70, extending in the left-right direction along the floor panel 70. The floor-side cross member 110 is, for example, welded to the upper surface of the rear floor portion 70b of the floor panel 70. The shape of the floor-side cross member 110 is not particularly limited, but in this embodiment, it bulges upward and opens downward, and has approximately the same cross-sectional shape over both left and right ends. By attaching the floor-side cross member 110 to the rear floor portion 70b, a closed cross section is formed by the floor-side cross member 110 and the rear floor portion 70b. The left end of the floor-side cross member 110 is located near the inner surface of the left side sill 73 in the vehicle width direction, and the right end of the floor-side cross member 110 is located near the inner surface of the right side sill 73 in the vehicle width direction. The floor-side cross member 110 may be attached to the lower surface of the rear floor portion 70b.

As shown in Figures 7 to 9, the left and right front side frames 72 are disposed at the front of the vehicle body and are high-strength members extending in the fore-and-aft direction. Only the right front side frame 72 is shown in Figures 7 to 9, and the left front side frame 72 is shown in Figure 2. In other words, the left and right front side frames 72 are positioned forward of the floor panel 70 and above the floor panel 70, and specifically, are disposed so as to extend forward from both the left and right sides of the lower part of the dash panel 71.

The left and right front side frames 72 have a symmetrical structure and can be constructed, for example, by joining multiple press-formed materials together or by extrusion. The cross section of each front side frame 72 in a direction perpendicular to the front-to-rear direction is set to be larger than the cross section of the front frame member 11 of the lower structure 2 in the same direction. This makes each front side frame 72 a thicker, stronger member than the front frame member 11.

The front ends of the left and right front side frames 72 each have a crash can 72a that is compressed and deformed during a frontal collision to absorb the collision energy. The crash can 72a is a cylindrical metal member that extends in the front-to-rear direction. A front bumper reinforcement 86 that extends in the left-to-right direction is fixed to the front ends of the left and right crash cans 72a.

As shown in FIG. 8, the upper part of the right-side connecting part 55 located in front of the lower structure 2 is connected to the right crash can 72a. The upper part of the left-side connecting part 53 (shown in FIG. 2) located in front of the lower structure 2 is connected to the left crash can 72a. Since the crash can 72a is located at the front end of the front side frame 72, by connecting the upper part of the left-side connecting part 53 to the crash can 72a, the connecting part of the left-side connecting part 53 can be set to a part close to the front end of the vehicle body. As a result, the distance between the left-side connecting parts 53 and 54 in the front-rear direction can be widened, so that the effect of connecting the front frame member 11 to the front side frame 72 by the left-side connecting parts 53 and 54 becomes even more remarkable. The same is true for the right-side connecting parts 55 and 56. The connecting structure of the left-side connecting parts 53 and 54 and the right-side connecting parts 55 and 56 to the front side frame 72 is a structure using fastening members such as bolts and nuts. The front left connecting portion 53 and the front right connecting portion 55 may be connected to a portion of the front side frame 72 behind the crash can 72a.

As shown in FIG. 5, the lower part of the rear right connecting part 56 is connected to the front frame member 11 behind the drive shaft 52, and as shown in FIG. 8, the upper part of the rear right connecting part 56 is connected to a part of the front side frame 72 that is rearward of the center in the fore-and-aft direction. This allows the fore-and-aft distance between the right connecting parts 55, 56 to be further increased. The same applies to the left connecting parts 53, 54.

The left and right side sills 73 are disposed so as to extend in the front-rear direction at both the left and right ends of the floor panel 70. As shown in FIG. 12, the left end of the floor panel 70 is connected to the vertical middle part of the left side sill 73, and the upper part of the side sill 73 protrudes upward from the connection part of the floor panel 70, and the lower part of the side sill 73 protrudes downward from the connection part of the floor panel 70. Since the battery case 10 is disposed below the floor panel 70, the lower part of the side sill 73 is disposed so as to overlap the battery case 10 in a side view of the vehicle. The right side sill 73 is also similarly connected to the right end part of the floor panel 70.

The left and right side sills 73 have a symmetrical structure. The detailed structure of the left side sill 73 will be described below with reference to FIG. 12. The left side sill 73 has an inner member 90 and an outer member 91 made of press-molded material. The inner member 90 is a member that constitutes the interior portion of the side sill 73, and is formed to bulge toward the interior of the vehicle cabin and to be long in the front-to-rear direction. The outer member 91 is a member that constitutes the exterior portion of the side sill 73, and is formed to bulge toward the exterior of the vehicle cabin and to be long in the front-to-rear direction. The upper parts of the inner member 90 and the outer member 91 are joined together, and the lower parts of the inner member 90 and the outer member 91 are joined together to form the hollow side sill 73.

A first recess 73a is formed in the lower part of the inner side in the vehicle width direction of the side sill 73, which is recessed outward in the vehicle width direction and extends in the front-rear direction. The first recess 73a is open downward and inward in the vehicle width direction. The outer side in the vehicle width direction of the battery case 10 of the lower structure 2 is formed to fit into the first recess 73a. Specifically, the left side member 20 of the battery case 10 enters the first recess 73a from below the first recess 73a. This allows the vehicle width dimension of the battery case 10 to be long, and the amount of downward protrusion of the battery case 10 can be reduced.

Inside the side sill 73, a hollow side load transfer member 120 is provided that extends in the front-rear direction and transfers loads from the outside to the inside in the vehicle width direction to the inside in the vehicle width direction. The side load transfer member 120 transfers loads that are not intended for normal driving, but are extremely large loads that cause deformation of the side members of the electric vehicle 1, such as in the case of a side collision in which an obstacle hits the side of the electric vehicle 1.

The lateral load transfer member 120 can be made of, for example, an extruded material, and is continuous from the front end to the rear end of the side sill 73. The lateral load transfer member 120 is fixed to the side sill 73 at an appropriate location. The fixing structure of the lateral load transfer member 120 to the side sill 73 is not particularly limited, but examples include a structure using fastening members such as bolts and nuts, rivets, etc.

The lateral load transfer member 120 has high rigidity so that it can transfer the load during a side collision to the inside in the vehicle width direction, and is resistant not only to compressive forces but also to bending and twisting forces, and functions as a reinforcing member that reinforces the side sill 73 during normal driving and contributes to improving the rigidity of the vehicle body. Such a lateral load transfer member 120 can be called an inner reinforcement because it is a member that reinforces the side sill 73 inside the side sill 73.

The side load transfer member 120 has an upper wall portion 121, an outer wall portion 122, an inner upper vertical wall portion 123, an inner lower vertical wall portion 124, an intermediate wall portion 125, and a lower wall portion 126. The upper wall portion 121 extends in the vehicle width direction and is disposed near the upper end portion inside the side sill 73. The outer wall portion 122 extends downward from the outer end portion in the vehicle width direction of the upper wall portion 121 and is disposed near the outer end portion in the vehicle width direction inside the side sill 73. The upper end portion of the outer wall portion 122 is located above the upper end portion of the floor side cross member 110. The lower end portion of the outer wall portion 122 is located below the upper end portion of the second battery side cross member 25B provided inside the battery case 10. Although not shown, the positional relationship between the first battery side cross member 25A and the third battery side cross member 25C and the side load transfer member 120 is also approximately the same.

The inner upper vertical wall portion 123 extends downward from the inner end of the upper wall portion 121 in the vehicle width direction, and is disposed inside the side sill 73 near the inner end in the vehicle width direction. The upper end of the inner upper vertical wall portion 123 is located above the upper end of the floor-side cross member 110. The lower end of the inner upper vertical wall portion 123 is located below the rear floor portion 70b and above the upper end of the second battery-side cross member 25B.

The middle wall portion 125 extends outward in the vehicle width direction from the lower end of the inner upper vertical wall portion 123. The outer end of the middle wall portion 125 in the vehicle width direction is located closer to the inside than the center of the upper wall portion 121 in the vehicle width direction. The inner lower vertical wall portion 124 extends downward from the inner end of the middle wall portion 125 in the vehicle width direction. The lower end of the inner lower vertical wall portion 124 is located lower than the upper end of the second battery side cross member 25B. The vertical dimension of the inner lower vertical wall portion 124 is set shorter than the vertical dimension of the inner upper vertical wall portion 123.

The lower part of the lateral load transfer member 120 on the interior side of the vehicle is formed with the inner lower vertical wall portion 124 and the intermediate wall portion 125 to form a second recess 120a that is recessed outward in the vehicle width direction so as to correspond to the first recess 73a of the side sill 73. The part of the side sill 73 where the first recess 73a is formed is designed to fit into the second recess 120a of the lateral load transfer member 120.

The lower wall portion 126 extends from the lower end of the inner lower vertical wall portion 124 to the lower end of the outer wall portion 122. The dimension of the lower wall portion 126 in the vehicle width direction is set to be longer than the dimension of the intermediate wall portion 125 in the vehicle width direction.

In a side view of the vehicle, an upper portion of the side load transfer member 120 overlaps with the floor-side cross member 110, and a lower portion of the side load transfer member 120 overlaps with the second battery-side cross member 25B. That is, the side load transfer member 120 has an inner upper vertical wall portion (first vertical wall portion) 123 that overlaps with the floor-side cross member 110 in a side view of the vehicle and extends in the vertical direction, and an inner lower vertical wall portion (second vertical wall portion) 124 that overlaps with the battery case 10 in a side view of the vehicle and extends in the vertical direction. The lower portion of the inner upper vertical wall portion 123 may overlap with the upper portion of the battery case 10.

First to fourth ribs 131 to 134 are integrally formed inside the side load transfer member 120. The first rib 131 extends in the vehicle width direction at a location spaced upward from the intermediate wall portion 125, and the inner end of the first rib 131 in the vehicle width direction is connected to the vertical middle portion of the inner upper vertical wall portion 123. The first rib 131 is inclined so that it is positioned higher as it moves outward in the vehicle width direction.

The second rib 132 extends in the vehicle width direction at a location spaced downward from the first rib 131, and the inner end of the second rib 132 in the vehicle width direction is connected to the upper end of the inner lower vertical wall portion 124. The outer end of the second rib 132 in the vehicle width direction is connected to the middle portion of the outer wall portion 122 in the up-down direction. The first rib 131 and the second rib 132 may extend substantially horizontally, or may be inclined so that they are positioned higher as they move toward the inside in the vehicle width direction, or may be inclined so that they are positioned higher as they move toward the outside in the vehicle width direction.

The third rib 133 extends upward from the upper end of the inner lower vertical wall portion 124. The upper end of the third rib 133 is connected to the middle portion of the upper wall portion 121 in the vehicle width direction. The third rib 133 is inclined so that it is positioned further outward in the vehicle width direction as it goes upward. The outer end of the first rib 131 in the vehicle width direction is connected to the middle portion of the third rib 133 in the up-down direction.

The fourth rib 134 extends in the vehicle width direction at a location spaced upward from the second rib 132. The inner end of the fourth rib 134 in the vehicle width direction is connected to the vertical middle part of the third rib 133. The outer end of the fourth rib 134 in the vehicle width direction is connected to the vertical middle part of the outer wall part 122. The inner end of the fourth rib 134 in the vehicle width direction and the outer end of the first rib 131 in the vehicle width direction are connected via the third rib 133, and the first rib 131 and the fourth rib 134 form one rib that is continuous in the vehicle width direction. The number and shape of the ribs formed inside the side load transmission member 120 are not limited to those described above, and the number of ribs may be three or less, or five or more.

The battery case 10 is fixed to the side sill 73 and directly fixed to the lateral load transmission member 120. A plurality of metallic tubular members 140 extending in the vertical direction are fixed to the left side member 20 of the battery case 10. The spacing between the tubular members 140 in the front-rear direction can be set to, for example, several tens of centimeters. The multiple tubular members 140 are arranged at intervals from each other in the front-rear direction as shown in FIG. 2. A bolt 141 is inserted into each tubular member 140 from below.

On the other hand, an opening is provided in the portion of the side sill 73 that corresponds to the inner surface of the first recess 73a so that the shaft of the bolt 141 can be inserted therethrough. Similarly, an opening is provided in the intermediate wall portion 125 of the side load transfer member 120 so that the shaft of the bolt 141 can be inserted therethrough, and both openings are aligned. A nut 142 is housed inside the side load transfer member 120. The nut 142 is fixed to the upper surface of the intermediate wall portion 125 of the side load transfer member 120. The number and positions of the openings and nuts 142 correspond to the number and positions of the tubular members 140.

Therefore, by inserting each bolt 141 into the cylindrical member 140, passing it through the openings of the side sill 73 and the openings of the lateral load transmission member 120, and screwing it into the nut 142 and tightening it, multiple locations on the left side of the battery case 10 can be fixed to the lateral load transmission member 120 and the side sill 73. The right side of the battery case 10 can also be fixed in the same way.

In this embodiment, the side load transfer member 120 is described as being integrally molded, but the present invention is not limited to this, and the side load transfer member 120 may be configured by combining multiple members. Although not shown, for example, the side load transfer member 120 may have a two-piece structure in which the vehicle width direction inner and outer parts are molded separately and then integrated. The side load transfer member 120 may also have a three-piece structure.

As shown in FIG. 7 etc., the upper structure 3 has a pair of left and right hinge pillars 150. The right hinge pillar 150 extends upward from the front end of the right side sill 73. As shown in FIG. 2, the left hinge pillar 150 extends upward from the front end of the left side sill 73. The left and right front doors 81 (shown in FIG. 1) are attached to the left and right hinge pillars 150, respectively.

As shown in FIG. 10, the upper structure 3 also includes a pair of left and right center pillars 157. The right center pillar 157 extends upward from the middle of the right side sill 73 in the fore-aft direction. As shown in FIG. 2, the left center pillar 157 extends upward from the middle of the left side sill 73 in the fore-aft direction. The left and right rear doors 82 (shown in FIG. 1) are attached to the left and right center pillars 157, respectively.

As shown in FIG. 9, the upper structure 3 is provided with a pair of left and right floor reinforcements (first longitudinal load transmission members) 151. The floor reinforcements 151 extend in the longitudinal direction along the upper surface of the front floor portion 70a. The front end of the right floor reinforcement 151 is connected to the rear end of the right front side frame 72. The rear end of the right floor reinforcement 151 is connected to the front end of the right side sill 73. Therefore, since the front side frame 72 and the side sill 73 are connected by the floor reinforcement 151, for example, when a collision load is input to the front side frame 72 during a frontal collision, the collision load is transmitted to the side sill 73 via the floor reinforcement 151.

The floor reinforcement 151 bulges upward and opens downward, and this bulging shape continues from the front end to the rear end. By attaching the floor reinforcement 151 to the upper surface of the front floor section 70a, a closed cross section is formed by the floor reinforcement 151 and the front floor section 70a.

Because the side sill 73 is positioned further outboard in the vehicle width direction than the front side frame 72, the floor reinforcement 151 extends while curving in a plan view so that it is positioned further outboard in the vehicle width direction as it moves rearward. The curved shape of this floor reinforcement 151 corresponds to the shape of the lower end of the front wheel house section 85. In other words, the floor reinforcement 151 extends along the lower end of the front wheel house section 85 and is connected to and integrated with the front wheel house section 85. The left floor reinforcement (not shown) has a symmetrical structure to the right one.

While the floor reinforcement 151 is attached to the upper surface of the front floor portion 70a, the outer connection portion 30 (shown in FIG. 3, etc.) of the lower structure 2 is located below the front floor portion 70a, so that the floor reinforcement 151 and the outer connection portion 30 are spaced apart from each other in the vertical direction. Similarly, the floor reinforcement 151 and the inner connection portion 31 are also spaced apart from each other in the vertical direction.

In addition, in a plan view, the portion of the right floor reinforcement 151 on the side sill 73 side (the rear end of the floor reinforcement 151) and the portion of the right outer connection part 30 on the battery case 10 side (the rear end of the outer connection part 30) overlap each other. The rear end of the floor reinforcement 151 is a portion connected to the side sill 73, so it is arranged adjacent to the side sill 73. On the other hand, the outer connection part 30 is a member connected to the battery case 10, so it is separated from the side sill 73. However, the fact that the rear end of the outer connection part 30 overlaps with the rear end of the floor reinforcement 151 in a plan view means that the rear end of the outer connection part 30 can be brought close to the side sill 73. Therefore, the collision load from the front can be reliably applied toward the side sill 73 side via the outer connection part 30. The same is true for the left side.

The rear end of the right floor reinforcement 151 and the base end (lower end) of the right hinge pillar 150 are located at the same position in the front-to-rear direction. In other words, the vicinity of the base end of the hinge pillar 150 in the side sill 73 is a particularly rigid part, and by connecting the rear end of the floor reinforcement 151 to this particularly rigid part, the collision load can be efficiently absorbed by the side sill 73.

As shown in FIG. 7, the upper structure 3 is provided with a pair of left and right lower load transmission members (second front-rear load transmission members) 152. The lower load transmission members 152 are disposed above the front frame member 11 of the lower structure 2, and the front frame member 11 and the lower load transmission members 152 are spaced apart from each other in the up-down direction. The lower load transmission members 152 extend in the front-rear direction along the lower surface of the front floor portion 70a. As shown in FIG. 11, the front end of the right lower load transmission member 152 is connected to the rear end of the right front side frame 72. Since the lower load transmission members 152 extend toward the front of the battery case 10, for example, when a collision load is input toward the rear of the front side frame 72 during a frontal collision, the collision load is transmitted to the front of the battery case 10 via the lower load transmission members 152. The left lower load transmission member 152 is symmetrical to the right one.

The lower load transfer member 152 bulges downward and opens upward, and this bulging shape continues from the front end to the rear end. By attaching the lower load transfer member 152 to the underside of the front floor portion 70a, a closed cross section is formed by the lower load transfer member 152 and the front floor portion 70a.

The rear of the right lower load transmission member 152 is positioned to the right of the front central member 26 and to the left of the right side member 21 within the battery case 10. The rear of the left lower load transmission member 152 is positioned to the left of the front central member 26 and to the right of the left side member 20 within the battery case 10.

As shown in Figures 7 to 9, a cross member 153 is disposed on the underside of the front floor portion 70a, extending in the left-right direction and connecting the rear of the left lower load transmission member 152 with the rear of the right lower load transmission member 152. The cross member 153 bulges downward and opens upward, and has a substantially uniform cross-sectional shape across both left-right ends. By attaching the cross member 153 to the underside of the front floor portion 70a, a closed cross section is formed by the cross member 153 and the front floor portion 70a. By disposing the cross member 153, it is possible to suppress the rear of the lower load transmission member 152 from being displaced in the left-right direction when the left and right lower load transmission members 152 receive a collision load during a frontal collision.

As shown in FIG. 11, the front end member 22 that constitutes the front part of the battery case 10 is disposed directly below the cross member 153. The front end member 22 is fastened to the cross member 153 by bolts and nuts (not shown). The fastening structure of the front end member 22 can be the same as the fastening structure of the left side member 20 to the side sill 73.

The front of the battery case 10 is provided with a protrusion 22a that protrudes upward. Specifically, the protrusion 22a is provided at a portion of the front end member 22 rearward of the cross member 153. This protrusion 22a is located rearward of the rear of the lower load transmission member 152. The protrusion 22a is formed so that its upper end is located above the bottom surface of the cross member 153 and above the bottom surface of the rear of the lower load transmission member 152. As a result, the cross member 153 and the lower load transmission member 152 overlap with the protrusion 22a when viewed in the front-rear direction. The protrusion 22a is the portion to which the collision load is transmitted from the lower load transmission member 152 when the lower load transmission member 152 retreats due to the collision load during a frontal collision.

The protrusion 22a extends continuously in the left-right direction. In other words, during a frontal collision, it is conceivable that the rear of the lower load transmission member 152 may be displaced slightly in the left-right direction, but because the protrusion 22a is continuous in the left-right direction, the collision load is reliably input to the protrusion 22a even if the rear of the lower load transmission member 152 is displaced in the left-right direction. Note that the protrusion 22a is not limited to being continuous in the left-right direction, but may be discontinuous and may overlap at least a portion of the rear of the lower load transmission member 152 when viewed in the front-rear direction.

The protruding portion 22a may be integrally molded with the front end member 22, or may be composed of a separate member. When the front end member 22 is an extruded material, the protruding portion 22a can be easily integrally molded. The protruding portion 22a may be fixed, for example, to the bottom plate 24, or to the left side member 20 or the right side member 21, etc. The protruding portion 22a may have any shape, such as a plate shape (rib shape), a rod shape, or a tube shape. By integrally molding the protruding portion 22a with the front end member 22 in a rib shape, a reinforcing effect of the front end member 22 can also be obtained.

The rear of the lower load transmission member 152 and the protruding portion 22a are disposed at a predetermined distance in the front-rear direction. By leaving a predetermined distance, the lower load transmission member 152 and the protruding portion 22a do not come into contact with each other during normal driving, and therefore, interference noise and the like are avoided. On the other hand, when the lower load transmission member 152 moves rearward during a frontal collision, the rear of the lower load transmission member 152 comes into contact with the protruding portion 22a, so that the collision load is reliably input to the protruding portion 22a. In other words, the above-mentioned predetermined distance is a distance set so that the lower load transmission member 152 and the protruding portion 22a do not come into contact with each other during normal driving, and the rear of the lower load transmission member 152 comes into contact with the protruding portion 22a during a frontal collision, and can be, for example, several mm to several cm. The rear of the lower load transmission member 152 and the protruding portion 22a may be abutted against each other. The rear of the lower load transmission member 152 and the protruding portion 22a may also be joined by a fastening member.

In addition, in the embodiment shown in FIG. 6, the front central member 26 in the battery case 10 is provided below the front floor portion 70a and is taller than the first to third rear central members 27 to 29. Therefore, the vertical dimension of the front central member 26 is longer, and the front central member 26 with a large cross section is located at the front of the battery case 10. This suppresses deformation of the battery case 10 when the collision load transmitted from the lower load transmission member 152 is received at the front of the battery case 10.

(Connection structure between rear of battery case and upper structure)
As shown in FIG. 13, the rear of the battery case 10 and the upper structure 3 are connected by a connecting member 160. Before describing this connecting structure, the structure of the rear side of the upper structure 3 will be described. On both the left and right sides of the rear of the upper structure 3, rear wheel house sections 170 (only the right one is shown in FIGS. 7 to 9) for accommodating the left and right rear wheels R are provided. The luggage compartment floor section 70e constituting the floor surface of the luggage compartment R2 in the floor panel 70 extends rearward from the rear of the kick-up section 70c and is located higher than the rear floor section 70b. The rear floor section 70b is the first floor section, and the kick-up section 70c and the luggage compartment floor section 70e are the second floor section which is relatively higher. The left end of the luggage compartment floor section 70e is connected to the lower part of the left rear wheel house section 170 (shown in FIG. 2), and the right end of the luggage compartment floor section 70e is connected to the right rear wheel house section 170 (shown in FIGS. 7 to 9).

As shown in Figures 7 to 9, a rear cross member (first cross member) 171 extending in the left-right direction is attached to the underside of the kick-up portion 70c. The rear cross member 171 bulges downward and opens upward, and this bulging shape continues from the left end to the right end. By attaching the rear cross member 171 to the underside of the kick-up portion 70c, a closed cross section is formed by the rear cross member 171 and the kick-up portion 70c.

A rear floor side cross member 172 extending in the left-right direction directly above the rear cross member 171 is attached to the upper surface of the kick-up portion 70c. The rear floor side cross member 172 bulges upward and opens downward, with this bulging shape continuing from the left end to the right end. By attaching the rear floor side cross member 172 to the upper surface of the kick-up portion 70c, a closed cross section is formed by the rear floor side cross member 172 and the kick-up portion 70c. In a plan view, the rear floor side cross member 172 and the rear cross member 171 overlap.

The right end of the rear floor cross member 172 is connected to the right rear wheel house section 170, and the left end of the rear floor cross member 172 is connected to the left rear wheel house section 170. The right end of the rear floor cross member 172 is connected to the lower end of a side reinforcement 173 extending upward along the right rear wheel house section 170. The left end of the rear floor cross member 172 is connected to the lower end of a side reinforcement (not shown) extending upward along the left rear wheel house section 170. The upper part of the right side reinforcement 173 and the upper part of the left side reinforcement are connected by a connecting member 174 (shown in Figures 8 and 9) extending in the left-right direction. In other words, a ring-shaped structure is formed by the rear floor cross member 172, the left and right side reinforcements 173, and the connecting member 174. The ring-shaped structure may be formed by using a reinforcement (not shown) provided up to the roof 80 side.

On the other hand, as shown in FIG. 13, the battery case 10 has a case-side cross member (second cross member) 180 (omitted in FIGS. 2 to 6). The case-side cross member 180 extends in the left-right direction and is attached to the rear end member 23 that constitutes the rear of the battery case 10. The case-side cross member 180 is located above the rear end member 23. The case-side cross member 180 and the rear cross member 171 are arranged to face each other in the up-down direction.

As shown in FIG. 13, the connecting member 160 is a member for connecting the rear end member 23 of the battery case 10 and the kick-up portion 70c. As a result, the kick-up portion 70c is reinforced by utilizing the battery case 10, improving the rigidity of the kick-up portion 70c. Improving the rigidity of the kick-up portion 70c also improves the rigidity of the entire floor panel 70. In this embodiment, the connecting member 160 is made of a plate material extending in the left-right and up-down directions, but is not limited thereto and may be a member with a closed cross section, an axial member, a cylindrical member, or the like extending in the up-down direction or diagonally. In addition, multiple connecting members 160 may be provided.

The upper part of the connecting member 160 is fixed to the lower part of the rear cross member 171. As a result, the battery case 10 and the kick-up part 70c are connected by the connecting member 160 via the rear cross member 171. In other words, the upper part of the connecting member 160 can be fixed to the part whose rigidity has been improved by the provision of the rear cross member 171, so that the fixing strength of the connecting member 160 to the kick-up part 70c can be increased. The fixing structure of the upper part of the connecting member 160 can be a detachable fastening structure using fastening members such as bolts and nuts (not shown). The upper part of the connecting member 160 may be directly connected to the kick-up part 70c.

The lower part of the connecting member 160 is fixed to the case-side cross member 180 that constitutes part of the battery case 10. This allows the lower part of the connecting member 160 to be fixed to a part of the battery case 10 with improved rigidity, thereby increasing the fixing strength of the connecting member 160 to the battery case 10. The lower part of the connecting member 160 may be detachably fixed to the battery case 10 by the fastening member. The connecting member 160 may be a component of the upper structure 3 side or a component of the lower structure 2 side.

(Relative position of the upper structure and lower structure cross members)
14 is a schematic diagram showing the positional relationship between the cross members of the upper structure 3 and the lower structure 2 according to a modified embodiment. First to third floor-side cross members 110A, 110B, 110C extending in the vehicle width direction are attached to the upper surface of the floor panel 70 of the upper structure 3, and a cross member 153 is attached to the underside of the floor panel 70. The cross member 153 is attached to the floor panel 70 and is therefore a floor-side cross member.

The first floor cross member 110A is the above-mentioned cross member 110, and is positioned rearward from the cross member 153. The second floor cross member 110B is positioned rearward from the first floor cross member 110A. The third floor cross member 110C is positioned rearward from the second floor cross member 110B. Meanwhile, the battery case 10 of the lower structure 2 is provided with the above-mentioned first to third battery side cross members 25A, 25B, 25C. In a side view, the cross member 153, the first to third floor side cross members 110A, 110B, 110C and the first to third battery side cross members 25A, 25B, 25C overlap with the side sill 73 (shown in FIG. 10, etc.).

In a side view of the vehicle, the cross member 153 and the first to third floor side cross members 110A, 110B, 110C are offset from the first to third battery side cross members 25A, 25B, 25C in the fore-and-aft direction of the vehicle. In other words, from the front to the rear of the vehicle, the cross member 153, the first battery side cross member 25A, the first floor side cross member 110A, the second battery side cross member 25B, the second floor side cross member 110B, the third battery side cross member 25C, and the third floor side cross member 110C are positioned in that order, and the cross member 153, the first to third floor side cross members 110A, 110B, 110C, and the first to third battery side cross members 25A, 25B, 25C are arranged alternately in the fore-and-aft direction.

For example, when looking at the first floor side cross member 110A and the second floor side cross member 110B, the second battery side cross member 25B is located in front of the first floor side cross member 110A and behind the second floor side cross member 110B. On the other hand, when looking at the first battery side cross member 25A and the second battery side cross member 25B, the first floor side cross member 110A is located behind the first battery side cross member 25A and in front of the second battery side cross member 25B. This positional relationship is said to be "displaced in the fore-and-aft direction of the vehicle."

In addition, "displaced in the vehicle fore-and-aft direction" may include other configurations. For example, it may include a configuration in which the fore-and-aft center of the first floor-side cross member 110A and the fore-and-aft center of the second battery-side cross member 25B are offset in the fore-and-aft direction. In this case, the configuration shown in FIG. 14 is also included, but it also includes a configuration in which, for example, the rear part of the first floor-side cross member 110A and the front part of the second battery-side cross member 25B are in an overlapping positional relationship in a plan view.

In addition, for example, a configuration in which the front of the first floor side cross member 110A is located in front of the front of the second battery side cross member 25B, and a configuration in which the rear of the second battery side cross member 25B is located behind the rear of the first floor side cross member 110A are also included in "displaced in the fore-and-aft direction of the vehicle."

During a side collision, the collision load can be received by the cross member 153 and the first to third floor side cross members 110A, 110B, 110C and the first to third battery side cross members 25A, 25B, 25C. Because the cross member 153 and the first to third floor side cross members 110A, 110B, 110C and the first to third battery side cross members 25A, 25B, 25C are offset in the fore-and-aft direction of the vehicle as described above, the collision load of the obstacle can be input to any of the floor side cross members 153, 110A, 110B, 110C and the battery side cross members 25A, 25B, 25C, even if the obstacle is a thin object such as a pole.

In a side view of the vehicle, only the floor-side cross-members 110A, 110B, 110C and the battery-side cross-members 25A, 25B, 25C in the area that does not overlap with the hinge pillar 150 (shown by a phantom line in FIG. 14) are shifted in the fore-aft direction. In other words, the floor-side cross-members 110A, 110B, 110C and the battery-side cross-members 25A, 25B, 25C located rearward of the hinge pillar 150 are shifted in the fore-aft direction. In other words, the area where the hinge pillar 150 is located has high strength against a lateral collision load, so the collision load can be received by the hinge pillar 150 even if the floor-side cross-members and the battery-side cross-members are not shifted in the fore-aft direction.

Similarly, only the floor-side cross members 110A, 110C and the battery-side cross members 25A, 25B, 25C that are in an area that does not overlap with the center pillar 157 in a side view of the vehicle may be shifted in the fore-and-aft direction.

(Effective in the event of a frontal collision)
Next, a case where the electric vehicle 1 configured as described above is involved in a frontal collision will be described. The collision load during the frontal collision is input to the left and right front side frames 72 via the front bumper reinforcement 86. The collision load during the frontal collision is also input to the left and right front frame members 11.

As for the front frame member 11, multiple parts of the front frame member 11 that are separated in the fore-and-aft direction are connected to the left front side frame 72 by the left connecting parts 53, 54, respectively, so that the left front frame member 11 to which a collision load is input is stabilized and is less likely to tilt left-right or up-down. The same is true for the right front frame member 11. As a result, the collision load is transmitted linearly to the front of the battery case 10 by the left and right front frame members 11.

At this time, since the front frame member 11 is connected to the battery case 10 at multiple locations spaced apart from each other in the left-right direction by the outer connection portion 30 and the inner connection portion 31, the collision load input to the front frame member 11 is input to multiple locations in the battery case 10 spaced apart in the left-right direction. Since the battery case 10 includes a front center member 26, a left side member 20, and a right side member 21 that extend in the front-rear direction, the collision load input to multiple locations spaced apart in the left-right direction is distributed and transmitted to the front center member 26, the left side member 20, and the right side member 21. This makes it possible to actively use the battery case 10 to absorb the collision load, so that the amount of collision load absorbed by the lower structure 2 can be increased, and the strength of the front side frame 72 and the strength of the members near the rear end of the front side frame 72 can be optimized to reduce the weight of the entire vehicle.

The collision load input to the front side frame 72 is transmitted to the side sill 73 via the floor reinforcement 151. The collision load input to the front frame member 11 can also be applied toward the side sill 73 via the outer connection portion 30, since the outer connection portion 30 extends toward the side sill 73. At this time, since the floor reinforcement 151 and the outer connection portion 30 are separated in the vertical direction, the route of the collision load transmitted from the front side frame 72 to the side sill 73 and the route of the collision load acting from the front frame member 11 toward the side sill 73 are different routes, and therefore the collision load is transmitted to the side sill 73 via multiple routes. The side sill 73 is a particularly high-rigidity member among the members that constitute the vehicle body, so the collision load can be absorbed by the side sill 73.

The collision load input to the front side frame 72 is transmitted from the rear of the front side frame 72 to the battery case 10 via both the floor reinforcement 151 and the lower load transmission member 152. This also forms a route for the collision load to be transmitted to the battery case 10 via the lower load transmission member 152, so that the collision load is dispersed and absorbed by both the side sill 73 and the battery case 10. In addition, because the floor reinforcement 151 and the lower load transmission member 152 are aligned along the floor panel 70, part of the collision load input to the floor reinforcement 151 and the lower load transmission member 152 is also transmitted to the floor panel 70 and absorbed by the floor panel 70.

In the case of an offset frontal collision, a large collision load is input to either the left or right side, and this embodiment is also effective in this case. In addition, in the case of a rear collision, the same effect can be achieved because the rear frame member 12 is provided.

(Effective in the event of a side collision)
Next, a case where the electric vehicle 1 configured as described above is subjected to a side collision will be described. The collision load during the side collision is input to the side sill 73 from the outside to the inside in the vehicle width direction. Since the side load transmission member 120 is provided inside the side sill 73, the collision load is input to the side load transmission member 120 from the outside to the inside in the vehicle width direction. At this time, the inner upper vertical wall portion 123 of the side load transmission member 120 overlaps with the cross members 110 and 153 on the floor side, and the inner lower vertical wall portion 124 overlaps with the battery case 10, so that the collision load is distributed and transmitted to the cross members 110 and 153 on the floor side and the battery case 10. Since the cross members 110 and 153 on the floor side extend in the vehicle width direction while being attached to the floor panel 70, they have a large resistance to the load from the side, and thus a part of the collision load is absorbed, reducing the collision load input to the battery case 10, and the battery B is protected. Furthermore, since the battery case 10 is provided with the first to third battery side cross members 25A, 25B, 25C, the front end member 22 and the rear end member 23, the collision load can also be absorbed by the battery case 10.

In addition, when an obstacle such as a pole collides with the vehicle from the side, as shown in FIG. 14, the cross member 153 and the first to third floor side cross members 110A, 110B, 110C are offset from the first to third battery side cross members 25A, 25B, 25C in the fore-and-aft direction of the vehicle, so that the collision load can be input to one of the cross members. It is also possible that a thin pole collides between the first floor side cross member 110A and the second battery side cross member 25B. In this case, after the high-strength side load transfer member 120 receives the collision load of the pole, the collision load can be distributed and absorbed by at least the first floor side cross member 110A and the second battery side cross member 25B.

Furthermore, if the obstacle is a large-diameter pole or a car, the collision load will be input to both the floor-side cross members 110A, 110B, and 110C and the battery-side cross members 25A, 25B, and 25C, and the collision load will be distributed and transmitted to the floor panel 70 and the battery case 10.

The above-described embodiments are merely illustrative in all respects and should not be interpreted as limiting. Furthermore, all modifications and variations within the scope of the claims are within the scope of the present invention.

As explained above, the vehicle body structure according to the present invention is suitable for electric vehicles equipped with a driving motor and a battery.

1 Electric vehicle 10 Battery case 11 Front frame member 20 Left side member 21 Right side member 22 Front end member 22a Protrusions 25A, 25B, 25C First to third battery side cross members 26 Front central member (front reinforcing member)
27-29 1st to 3rd rear central members (rear reinforcing members)
30 Outer connection part (one connection part)
31 Inner connection part (other connection part)
53, 54 Left side connecting portion 55, 56 Right side connecting portion 70 Floor panel 70a Front floor portion 70b Rear floor portion (first floor portion)
70c Kick-up section (second floor section)
72 Front side frame 73 Side sill 100 Seat fixing portion 110A, 110B, 110C First to third floor side cross members 120 Side load transmission member (inner reinforcement)
123 Inner upper vertical wall section (first vertical wall section)
124 Inner lower vertical wall portion (second vertical wall portion)
150: hinge pillar 151: floor reinforcement (first longitudinal load transmission member)
152 Lower load transmission member (second front-rear load transmission member)
153 Cross member 160 Connecting member 170 Rear wheel house portion 171 Rear cross member (first cross member)
180 Case side cross member (second cross member)
A Body structure B Battery M Driving motor

Claims (7)

A vehicle body structure for an electric vehicle including a driving motor and a battery case housing a battery that supplies power to the driving motor and is disposed below a floor panel,
a pair of left and right side frames disposed to extend in the front-rear direction of the vehicle on one side of the front-rear direction of the vehicle and above the floor panel;
a pair of left and right side sills disposed at both ends of the floor panel in a vehicle width direction so as to extend in a vehicle front-rear direction;
a floor reinforcement that connects the side frame and the side sill and transmits a load from the side frame to the side sill;
a frame member extending from the battery case downwardly of the side frame in one direction in the vehicle front-rear direction on the inner side of the side sill in the vehicle width direction ;
an outer connection portion extending outward in the vehicle width direction from a vehicle front-rear direction midway portion of the frame member toward the side sill side and connected to the battery case;
A vehicle body structure in which the floor reinforcement and the outer connection portion are spaced apart from each other in the up-down direction. The vehicle body structure according to claim 1,
A vehicle body structure, wherein a portion of the floor reinforcement on the side sill side and a portion of the outer connection portion on the battery case side are positioned so as to overlap each other in a plan view. The vehicle body structure according to claim 1 or 2,
A vehicle body structure in which an inner reinforcement extending in the vehicle front-rear direction is provided inside the side sill. The vehicle body structure according to any one of claims 1 to 3,
An inner connection portion extends from a vehicle front-rear direction midway portion of the frame member toward a vehicle width direction center of the battery case and is connected to the battery case,
A vehicle body structure in which a central member extending in a front-rear direction of the vehicle is provided in a center of the battery case in a vehicle width direction. The vehicle body structure according to any one of claims 1 to 4,
The frame member is disposed on the inner side of the side frame in a vehicle width direction. The vehicle body structure according to any one of claims 1 to 5,
A pair of left and right hinge pillars respectively extending upward from the pair of left and right side sills,
A vehicle body structure in which a portion of the floor reinforcement on the side sill side and a base end portion of the hinge pillar are disposed at the same position in the vehicle front-rear direction. The vehicle body structure according to any one of claims 1 to 6,
The floor reinforcement is formed to extend in the fore-and-aft direction of the vehicle along an upper surface of the floor panel, and is attached to the upper surface of the floor panel to form a closed cross section together with the floor panel.

Images