Patent Description:
In an automotive vehicle comprising a motor for vehicle driving (i.e., a driving motor), for example, a battery unit to supply electric power to the motor for vehicle driving is installed and this battery unit is designed to have a larger capacity so as to provide a longer drivable (cruising) distance.

The battery unit of the electric automotive vehicle disclosed in <CIT> (<CIT>) is installed in a wide range below a vehicle floor. A pair of right-and-left front side members extending in a vehicle longitudinal direction and a pair of under members extending in the vehicle longitudinal direction below the front side members are provided at a front part of a vehicle body of this automotive vehicle. Further, the battery unit provided below the vehicle floor comprises a case body portion. A pair of right-and-left front extension portions extending forward are formed at a front wall of the case body portion, and each rear end portion of the under members is connected to each front end portion of the front extension portions. Further, a pair of right-and-left rear extension portions extending rearward are integrally formed at a rear wall of the case body portion. The case body portion is fixed to a floor under reinforcement, and the front extension portion and the rear extension portion are respectively fixed to the front side member and the rear side member.

Meanwhile, there is a case where a floor panel of the automotive vehicle comprises a lower portion and a high portion. For example, there is the floor panel which is configured such that a portion corresponding to a foot space of a rear-seat passenger is located at a lower level and another portion corresponding to a sitting point of the rear-seat passenger is located at a higher level.

Herein, there is a problem how to properly improve the rigidity of the floor panel itself regardless of its large-sized plate-shaped member among various elements which constitute a vehicle body. This is because if the rigidity of the floor panel is low, decreasing of the vehicle-body rigidity is caused.

In general, a reinforcing member which is attached to each section of the vehicle body may improve the vehicle-body rigidity. However, the reinforcing member increases the size and weight of the vehicle body improperly, so that this member may not improve the vehicle-body rigidity efficiently.

In this regard, in the structure disclosed in the above-described patent document, while the case body of the battery unit is fixed to the floor under reinforcement, since the floor under reinforcement is the member extending horizontally in the longitudinal direction below the floor panel, a portion of the floor panel which is located at the high level cannot be fixed to the case body. That is, the low-level portion of the floor panel may be able to improve the rigidity by the floor under reinforcement and the case body, but the high-level portion of the floor panel is so spaced upward from the under reinforcement and the case body that its reinforcing effect by means of the under reinforcement and the case body may not be expected at all. Document <CIT> discloses a further example of a reinforced floor structure of an electric vehicle comprising a battery case.

The present invention has been devised in view of the above-described matters, and an object of the present invention is to provide a vehicle-body structure of an electric automotive vehicle which can efficiently improve the rigidity of the high-level portion of the floor panel (i.e., the portion of the floor panel which is located at the high level) by utilizing the battery case which is provided below the floor panel.

The present invention is a vehicle-body structure of an electric automotive vehicle, in which a motor for vehicle driving is provided and a battery case where a battery to supply electric power to the motor for vehicle driving is stored is arranged below a floor panel, wherein the floor panel comprises a first floor portion and a second floor portion located at a higher level than the first floor portion, and a connecting member connecting the battery case and the second floor portion is provided.

According to the present invention, the first floor portion located at the relatively low level and the second floor portion located at the relatively high level are formed at the floor panel. The second floor portion is connected to the battery case by the connecting member. This battery case stores the battery, a heavy object, and therefore the battery case is configured to have high strength. Accordingly, since the second floor portion is reinforced by utilizing the battery case having the high strength without providing any heavy reinforcing member additionally, the rigidity of the second floor portion can be improved efficiently.

According to the invention, a first cross member extending in a vehicle width direction is attached to a lower face of the second floor portion, an upper portion of the connecting member is fixed to the first cross member, and the battery case and the second floor portion are connected via the first cross member by the connecting member.

According to the invention, since a portion which is reinforced by the first cross member can be connected by the connecting member, the rigidity of the second floor portion can be improved further more.

According to the invention, the battery case comprises a second cross member extending in the vehicle width direction, and a lower portion of the connecting member is fixed to the second cross member.

According to the invention, since the battery case which is reinforced by the second cross member can be connected by the connecting member, the rigidity of the second floor portion can be improved further more.

According to the invention, the first cross member and the second cross member are provided to face each other in a vertical direction.

According to the invention, the connecting member is formed by a plate member which extends in the lateral direction and in the vertical direction.

According to this embodiment, since the first cross member and the second cross member are close to each other, the dimension, in the vertical direction, of the connecting member can be shorter, thereby further improving the reinforcing effect.

In another embodiment of the present invention, a pair of right-and-left wheelhouse portions are connected to both end portions, in the vehicle width direction, of the second floor portion, and both end portions of the first cross member are connected to the right-and-left wheelhouse portions.

According to this embodiment, a load which is inputted to the wheelhouse portion during vehicle traveling, for example, can be dispersed to the battery case through the first cross member, the second floor portion, and the connecting member, thereby improving the vehicle-body rigidity further more.

In another embodiment of the present invention, a floor-side cross member which extends in the vehicle width direction just above the first cross member is attached to an upper face of the second floor portion.

According to this embodiment, the high-rigidity portion of the second floor portion can be connected by the connecting member, thereby improving the reinforcing effect further more.

The present invention will become apparent from the following description which refers to the accompanying drawings.

Hereafter, embodiments of the present invention will be described specifically referring to the drawings. The following preferred embodiments just exemplify essentially, and therefore these do not limit the present invention, its adaption, or its use.

<FIG> is a left side view of an electric automotive vehicle <NUM> which is provided with a vehicle-body structure A according to the embodiment of the present invention. This electric automotive vehicle <NUM> comprises, as shown in <FIG>, a lower structural body <NUM> and an upper structural body <NUM>, and the vehicle-body structure A is constituted by the lower structural body <NUM> and the upper structural body <NUM>. <FIG> shows a state where doors, a bonnet hood, a front fender, a widow glass, a bumper, front-and-rear lights, and others are removed. Herein, in the following description of the present embodiment, a vehicle front side is just referred to as "front," a vehicle rear side is just referred to as "rear," a vehicle right side is just referred to as "right," and a vehicle left side is just referred to as "left. " A lateral direction of the vehicle is a vehicle width direction.

As shown in <FIG>, the electric automotive vehicle <NUM> is a passenger car. As shown in <FIG>, a front seat S1 is provided at a front side in a cabin R1 as a residential space of passengers, and a rear seat S2 is provided in back of the front seat S1 in the cabin R1. A baggage room R2 is provided in back of the rear seat S2 as needed. The cabin R1 and the baggage room R2 are provided at the upper structural body <NUM>. Herein, only the front seat S1 may be provided in the cabin R and a third-row seat (not illustrated) may be provided behind the rear seat S2.

Meanwhile, a front space before the cabin R1 of the electric automotive vehicle <NUM> can be constituted by a power room R3, for example. That is, the vehicle-body structure A comprises a motor for vehicle driving M (hereafter, referred to as the "driving motor") to generate driving power to drive vehicle's driving wheels and a battery case <NUM> where a battery B (shown only in <FIG>) to supply electric power are provided. A powertrain PT is constituted by the driving motor M only, or by the driving motor M, reduction gears, a transmission, and others. <FIG> and <FIG> show a case where the powertrain PT is provided only in the power room R3, but the powertrain PT may be provided in a lower space R4 of the baggage room R2 (not illustrated). In the case where the powertrain PT is provided only in the power room R3, only front wheels F are driven. In the case where the powertrain PT is provided in the lower space R4, only rear wheels R are driven. In this case, the power room R3 is usable as a baggage-room space or the like. Further, in a case where the powertrain PT is provided both in the power room R3 and the lower space R4, this vehicle is a four-wheel drive car. The battery case <NUM> is arranged below a floor panel <NUM> which will be described later.

As shown in <FIG> and <FIG>, the lower structural body <NUM> comprises the battery case <NUM>, a pair of front frame members <NUM> which extend forward in front of the battery case <NUM> and a pair of rear frame members <NUM> which extend rearward in back of the battery case <NUM>. In <FIG>, illustration of the left-side elements, such as the front wheel F, the rear wheel R, suspension arms, and others is omitted.

In a case of the general electric automotive vehicle, the battery case is detachably attached below the floor, separately from a vehicle body. In the present embodiment, however, the front frame members <NUM> and the rear frame members <NUM> are integrally formed at the battery case <NUM>, and these members <NUM>, <NUM>, <NUM> are together detachably attached to the upper structural body <NUM>.

Specifically, the electric automotive vehicle <NUM> of the present embodiment is vertically split into the lower structural body <NUM> provided with the battery case <NUM> and the upper structural body <NUM> provided with the cabin R1 and the baggage room R2. This vertical-split constitution means the structure where the lower structural body <NUM> is integrally attached to the upper structural body <NUM> by fastening members, such as bolts and nuts or screws, without using welding, adhesion, or the like. Thereby, when maintenance or repair are conducted for the electric automotive vehicle <NUM> after a user gets it, the lower structural body <NUM> can be separated from the upper structural body <NUM> as needed, so that the maintenance performance can be superior.

Herein, a radar-frame type of vehicle-body structure is known as the vehicle-body structure of the automotive vehicle. In a case of the radar-frame type of vehicle-body structure, the structure is vertically splitable into a radar frame and a cabin, wherein the radar frame continuously extends in a longitudinal direction and therefore this radar frame receives a collision load mainly in a vehicle frontal collision and a vehicle rear collision. In a vehicle side collision, the radar frame receives the collision load supplementally and the cabin receives the collision load mainly. Thus, in the radar-frame type of vehicle-body structure, it is usual that the member receiving the collision load of the vehicle frontal/rear collision is separated from the member receiving the collision load of the vehicle side collision.

Meanwhile, in the case of the electric automotive vehicle <NUM> of the present embodiment in which the lower structural body <NUM> provided with the frame members <NUM>, <NUM> and the upper structural body <NUM> are splitable, the collision load is received by the lower structural body <NUM> and the upper structural body <NUM> both in the vehicle frontal/rear collision and in the vehicle side collision, so that the technology concept of the present embodiment is considerably different from that of the conventional radar-frame type of vehicle-body structure in dispersing the collision load to the both structural bodies <NUM>, <NUM> and absorbing the collision load. Hereafter, the structure of the lower structural body <NUM> and the upper structural body <NUM> and their operational effects will be described in order.

The lower structural body <NUM> will be described first. As shown in <FIG> and <FIG>, the lower structural body <NUM> comprises the powertrain PT, the front wheels F, the rear wheels R, front suspension devices <NUM>, and rear suspension devices <NUM> in addition to the battery case <NUM>, the front frames <NUM>, and the rear frames <NUM>. Any type of suspension is applicable to the front suspension device <NUM> and the rear suspension device <NUM>.

The battery case <NUM> is a large-sized case which extends, below the floor panel <NUM> described later, from the vicinity of its left end portion to the vicinity of its right end portion and also extends from the vicinity of its front end portion to the vicinity of its rear end portion. By providing the battery case <NUM> in a wide range below the floor panel <NUM> as described above, the battery B having a large capacity can be installed to the electric automotive vehicle <NUM> as shown in <FIG>. The battery B may be constituted by a lithium-ion battery, an all-solid battery, or the like, or any other secondary battery. Further, the battery B may be a so-called battery cell or a battery pack storing plural battery cells.

The battery case <NUM> comprises a left-side member <NUM>, a right-side member <NUM>, a front-end member <NUM>, a rear-end member <NUM>, and a bottom plate <NUM>. The left-side member <NUM>, the right-side member <NUM>, the front-end member <NUM>, and the rear-end member <NUM> are respectively made of an aluminum-alloy extruded member, for example, but these may be formed by pressing an aluminum-alloy made plate member or a steel plate. The bottom plate <NUM> can be also made of an extruded member. In the following description, the "extruded member" means the aluminum-alloy extruded member, and the "pressing member" means the aluminum-alloy made plate member or the steel plate which are formed through pressing. Moreover, each member may be made of a casting.

Each cross section, in a perpendicular direction to a longitudinal direction, of the left-side member <NUM>, the right-side member <NUM>, the front-end member <NUM>, and the rear-end member <NUM> is configured to be rectangular. Further, the left-side member <NUM>, the right-side member <NUM>, the front-end member <NUM>, and the rear-end member <NUM> are located at the same level and extend substantially horizontally.

The left-side member <NUM> is provided at a left end portion of the battery case <NUM> and extends in the longitudinal direction. The right-side member <NUM> is provided at a right end portion of the battery case <NUM> and extends in the longitudinal direction. Further, the front-end member <NUM> is provided at a front end portion of the battery case <NUM> and extends in the lateral direction. A left end portion of the front-end member <NUM> and a front end portion of the left-side member <NUM> are interconnected, and a right end portion of the front end member <NUM> and a front end portion of the right-side member <NUM> are interconnected. The rear-end member <NUM> is provided at a rear end portion of the battery case <NUM> and extends in the lateral direction. A left end portion of the rear-end member <NUM> and a rear end portion of the left-side member <NUM> are interconnected, and a right end portion of the rear-end member <NUM> and a rear end portion of the right-side member <NUM> are interconnected. The bottom plate <NUM> extends substantially horizontally and is fixed to respective lower faces of the left-side member <NUM>, the right-side member <NUM>, the front-end member <NUM>, and the rear-end member <NUM>. Accordingly, a battery storage space S (shown in <FIG>) which stores the battery B is partitioned by the left-side member <NUM>, the right-side member <NUM>, the front-end member <NUM>, the rear-end member <NUM>, and the bottom plate <NUM>.

The size of the battery storage space S is changeable according to the capacity of the battery B installed. The size of the battery storage space S is easily changeable by each length of the left-side member <NUM>, the right-side member <NUM>, the front-end member <NUM>, and the rear-end member <NUM> and a shape of the bottom plate <NUM>. For example, in a case where the vehicle is a small (compact) car with a short wheel base and a narrow tread, the size of the battery storage space S becomes small by configuring the vehicle such that the left-side member <NUM>, the right-side member <NUM>, the front-end member <NUM>, and the rear-end member <NUM> are respectively short and the shape of the bottom plate <NUM> is small (see <FIG>). In a case where the vehicle is a large car, meanwhile, by configuring the vehicle such that the left-side member <NUM>, the right-side member <NUM>, the front-end member <NUM>, and the rear-end member <NUM> are respectively long and the shape of the bottom plate <NUM> is large, the size of the battery storage space S becomes large. In a case where the left-side member <NUM>, the right-side member <NUM>, the front-end member <NUM>, and the rear-end member <NUM> are respectively made of the extruded member, their length can be changed easily. Further, the bottom plate <NUM> can be made of the extruded member, whereby its shape can be changed easily.

An upper side of the battery storage space S may be closed with a cover body, not illustrated, or the floor panel <NUM>, described later. A cooling device to cool the battery B or a heating device to heat the battery B (temperature controller), except the battery B, can be provided in the battery storage space S. Further, the electric power of the battery B is supplied to the driving motor M by a controller, not illustrated. Moreover, charging of the battery B is possible by a charging socket, not illustrated.

As shown in <FIG>, first - third battery-side cross members 25A, 25B, 25C are provided inside the battery case <NUM> as reinforcing members extending in the lateral direction. These members 25A, 25B, 25C have the same level which is substantially equal to the level of the left-side member <NUM> and the like. These members 25A, 25B, 25C may be respectively made of the extruded member or the pressing member. While the three battery-side cross members 25A, 25B, 25C are provided in the present embodiment, the number of these members is changeable according to the longitudinal dimension of the battery case <NUM>.

The first - third battery-side cross members 25A, 25B, 25C are spaced apart from each other in the longitudinal direction, and the first battery-side cross member 25A is located at the foremost position and the third battery-side cross member 25C is located at the rearmost position. Each lower portion of these members 25A, 25B, 25C is fixed to an upper face of the bottom plate <NUM>. Further, each left end portion of these members 25A, 25B, 25C is fixed to an inner face (right-side face) of the left-side member <NUM>, and each right end portion of these members 25A, 25B, 25C is fixed to an inner face (left-side face) of the right-side member <NUM>. That is, these members 25A, 25B, 25C are members which interconnect the left-side member <NUM> and the right-side member <NUM>.

While <FIG> shows an example of the lower structural body <NUM> provided with the small-sized battery case <NUM> which has a shorter longitudinal dimension than the battery case <NUM> shown in <FIG>, illustration of the third battery-side cross member 25C is omitted because the longitudinal dimension of the example shown in <FIG> is short. On the contrary, a fourth battery-side cross member can be provided, which is not illustrated.

A front center member (front reinforcing member) <NUM> and first - third rear center members (rear reinforcing member) <NUM> - <NUM> are provided inside the battery case <NUM> as reinforcing members extending in the longitudinal direction. The front center member <NUM> and the first - third rear center members <NUM> - <NUM> have substantially the same level and are provided at the center, in the lateral direction, of the battery case <NUM>. Each lower end portion of the front center member <NUM> and the first - third rear center members <NUM> - <NUM> is attached to the upper face of the bottom plate <NUM>.

The front center member <NUM> is arranged between the front-end member <NUM> and the first battery-side cross member 25A, a front end portion of the front center member <NUM> is fixed to a central portion, in the lateral direction, of the front-end member <NUM>, and a rear end portion of the front center member <NUM> is fixed to a central portion, in the lateral direction, of the first battery-side cross member 25A. Accordingly, the front-end member <NUM> is a member which extends so as to interconnect respective front end portions of the left-side member <NUM> and the right-side member <NUM> and a front end portion of the front center member <NUM>.

The first rear center member <NUM> is arranged between the first battery-side cross member 25A and the second battery-side cross member 25B, a front end portion of the first rear center member <NUM> is fixed to the central portion, in the lateral direction, of the first battery-side cross member 25A, and a rear end portion of the first rear center member <NUM> is fixed to a central portion, in the lateral direction, of the second battery-side cross member 25B. Further, the second rear center member <NUM> is arranged between the second battery-side cross member 25B and the third battery-side cross member 25C, a front end portion of the second rear center member <NUM> is fixed to the central portion, in the lateral direction, of the second battery-side cross member 25B, and a rear end portion of the second rear center member <NUM> is fixed to a central portion, in the lateral direction, of the third battery-side cross member 25C. Moreover, the third rear center member <NUM> is arranged between the third battery-side cross member 25C and the rear end member <NUM>, a front end portion of the third rear center member <NUM> is fixed to the central portion, in the lateral direction, of the third battery-side cross member 25C, and a rear end portion of the third rear center member <NUM> is fixed to a central portion, in the lateral direction, of the rear end member <NUM>. Accordingly, the first - third battery-side cross members 25A, 25B, 25C and the front central member <NUM> and the first - third rear center members <NUM> - <NUM> are arranged in a latticed pattern and interconnected mutually inside the battery case <NUM>, whereby the reinforcing effect of the battery case is further improved.

When an imaginary straight line which extends in the longitudinal direction in a plan view is considered, the front center member <NUM> and the first - third rear center members <NUM> - <NUM> are set such that they are positioned on this imaginary straight line. That is, the first - third rear center members <NUM> - <NUM> are positioned on part of this imaginary line which extends rearward from the front center member <NUM>. Herein, the front center member <NUM> and the first - third rear center members <NUM> - <NUM> may constituted by a single member which is continuous in the longitudinal direction.

<FIG> is a diagram which shows an example where the level of the front center member <NUM> is higher than that of the first - third rear center members <NUM> - <NUM> (not illustrated in <FIG>). The floor panel <NUM> of the upper structural body <NUM> is configured such that its front floor portion 70a is located above its rear floor portion 70b, which is specifically described later. The front center member <NUM> is provided below the front floor portion 70a, and the first - third rear center members <NUM> - <NUM> are provided below the rear floor portion 70b. An upper end portion of the front center member <NUM> is located above the rear floor portion 70b. In other words, respective upper end portions of the first - third rear center members <NUM> - <NUM> are positioned below the upper end portion of the front center member <NUM>, which corresponds to a structure in which the rear floor portion 70b is located at a relatively low level. Herein, the first battery-side cross member 25A may be positioned below the front floor portion 70a, and in this case, an upper end portion of the first battery-side cross member 25A can be configured to be located above the second and third battery-side cross members 25B, 25C.

As shown in <FIG> and <FIG>, the front frame member <NUM> is provided at each side, in the vehicle width direction, of the vehicle body and extends substantially horizontally and straightly below the front side frame <NUM>. The front frame member <NUM> may be made of the extruded member, the pressing member, or the like. In the present embodiment, since the front frame member <NUM> is made of the extruded member, its cross section perpendicular to the longitudinal direction is substantially the same over its entire length from its front end portion to its rear end portion.

The left-side front frame member <NUM> is connected to part of the front-end member <NUM> constituting the front portion of the battery case <NUM> which is positioned on the left side of the center, in the lateral direction, of the front-end member <NUM>, and this connection point is positioned on the right side of the left-side member <NUM> of the battery case <NUM>. Further, the right-side front frame member <NUM> is connected to part of the front-end member <NUM> which is positioned on the right side of the center, in the lateral direction, of the front-end member <NUM>, and this connection point is positioned on the left side of the right-side member <NUM> of the battery case <NUM>. Thereby, the distance between the right-and-left front frame members <NUM> becomes a specified distance, whereby a lower portion of the powertrain PT can be arranged between the right-and-left front frame members <NUM>. The distance between the right-and-left front frame members <NUM> is set to be narrower than that between the left-side member <NUM> and the right-side member <NUM> of the battery case <NUM>.

The right-and-left front frame members <NUM> have substantially the same level. Further, the right-and-left front frame members <NUM> and the front center member <NUM>, the left-side member <NUM>, and the right-side member <NUM> of the battery case <NUM> are located substantially at the same level.

Respective portions (rear sides) of the front frame members <NUM> which are positioned on the side of the battery case <NUM> are connected to the battery case <NUM> at plural points which are spaced apart from each other in the lateral direction. Specifically, a rear end portion of the right-side front frame member <NUM> is connected to the front-end member <NUM>, and a portion of the front frame member <NUM> which is spaced forward from the rear end portion of the front frame member <NUM> is connected to the front-end member <NUM> by an outside connection portion (one-side connection portion) <NUM> and an inside connection portion (other-side connection portion) <NUM>. Thereby, the collision load inputted to the front frame member <NUM> in the vehicle frontal collision can be dispersed and transmitted to plural points of the battery case <NUM>.

The outside connection portion <NUM> and the inside connection portion <NUM> are made of the high-rigidity member, such as the extruded member or the pressing member, which have a cylindrical, plate, or columnar shape. The width of each of the outside connection portion <NUM> and the inside connection portion <NUM> is set to be wider than that of the front frame member <NUM> in the plan view, whereby the dispersion performance of the collision load is further improved. Herein, the width of each of the outside connection portion <NUM> and the inside connection portion <NUM> may be set to be equal to that of the front frame member <NUM> or narrower than that of the front frame member <NUM>.

The right-side outside connection portion <NUM> is provided substantially at the same level as the front frame member <NUM> at the right side (the outward side in the vehicle width direction) of the right-side front frame member <NUM>, and the right-side outside connection portion <NUM> is oblique in the longitudinal direction in the plan view such that its rear end portion is positioned further on the right side. A front end portion of the right-side outside connection portion <NUM> is connected to a portion (middle portion) of the front frame member <NUM> which is positioned between a center, in the longitudinal direction, of the front frame member <NUM> and a rear end portion of the front frame member <NUM>. The outside connection portion <NUM> extends rightward and rearward from its connection portion to the front frame member <NUM>, i.e., toward the side sill <NUM> (described later) of the upper structural body <NUM>. A rear end portion of the right-side outside connection portion <NUM> is connected to a portion of the front-end member <NUM> which is spaced rightward apart from the rear end portion of the front frame member <NUM>. A connecting structure of the outside connection portion <NUM> and the front frame member <NUM> and a connecting structure of the outside connection portion <NUM> and the front-end member <NUM> may be constituted in a connecting manner which uses fastening members, such as bolts and nuts, or welding or adhesion.

The right-side inside connection portion <NUM> is provided substantially at the same level as the front frame member <NUM> at the left side (the inward side in the vehicle width direction) of the right-side front frame member <NUM>, and the right-side inside connection portion <NUM> is oblique in the longitudinal direction in the plan view such that its rear end portion is positioned further on the left side. A front end portion of the right-side inside connection portion <NUM> is connected to a portion (middle portion) of the front frame member <NUM> which is positioned between a center, in the longitudinal direction, of the front frame member <NUM> and a rear end portion of the front frame member <NUM>. The inside connection portion <NUM> extends leftward and rearward from its connection portion to the front frame member <NUM>, i.e., toward the center, in the lateral direction, of the battery case <NUM>. A rear end portion of the inside connection portion <NUM> is connected to a portion of the front-end member <NUM> which is spaced leftward apart from the rear end portion of the front frame member <NUM>. A connecting structure of the inside connection portion <NUM> and the front frame member <NUM> and a connecting structure of the inside connection portion <NUM> and the front-end member <NUM> can be constituted in the same manner as the connecting structure of the outside connection portion <NUM>.

While the right-side front frame member <NUM> is connected to the front-end member <NUM> at three points which are spaced apart from each other in the lateral direction in the present embodiment, two-point connection may be applied by omitting either one of the outside connection portion <NUM> and the inside connection portion <NUM> or only the outside connection portion <NUM> and the inside connection portion <NUM> may be connected to the front-end member <NUM> without connecting the rear end portion of the front fame member <NUM> to the front-end member <NUM>.

Herein, the left-side front frame member <NUM> can be connected to the front-end member <NUM> similarly to the right-side front frame member <NUM>. The connecting structure of the left-side front frame member <NUM> can be a laterally-symmetrical structure relative to the right-side front frame member <NUM>.

As shown in <FIG>, a middle connecting member <NUM>, a front connecting member <NUM>, and a rear connecting member <NUM> are provided to be spaced apart from each other in the longitudinal direction. The front connecting member <NUM> extends in the vehicle width direction from a front portion of the left-side front frame member <NUM> to a front portion of the right-side front frame member <NUM> and interconnects the left-side front frame member <NUM> and the right-side front frame member <NUM>. Further, the rear connecting member <NUM> extends in the vehicle width direction from a rear portion of the left-side front frame member <NUM> to a rear portion of the right-side front frame member <NUM> and interconnects the left-side front frame member <NUM> and the right-side front frame member <NUM>. The front connecting member <NUM> and the rear connecting member <NUM> are made of the extruded member or the pressing member, for example. The right-and-left front frame members <NUM> are interconnected by the front connecting member <NUM> and the rear connecting member <NUM>, which forms a frame structure when viewed in the plan view.

Further, the middle connecting member <NUM> is provided between the front connecting member <NUM> and the rear connecting member <NUM> and extends from the front portion of the left-side front frame member <NUM> to the front portion of the right-side front frame member <NUM>, which interconnects the left-side front frame member <NUM> and the right-side front frame member <NUM>. The middle connecting member <NUM> may be omitted as needed.

The front connecting member <NUM> extends from an upper face of the left-side front frame member <NUM> to an upper face of the right-side frame member <NUM> and protrudes upward from the respective upper faces of these front frame members. Meanwhile, the rear connecting member <NUM> is arranged between the right-and-left front frame members <NUM>, and its left end portion is connected to a side face of the left-side front frame member <NUM> and its right end portion is connected to a side face of the right-side front frame member <NUM>. The front connecting member <NUM> and the rear connecting member <NUM> may be fixed to the front frame member <NUM> by fastening, welding, or adhesion.

The longitudinal dimension of each of the front connecting member <NUM> and the rear connecting member <NUM> is set to be longer than the lateral dimension of the front frame member <NUM>. Thereby, the connection strength of the front frame member <NUM> by means of the both connecting members <NUM>, <NUM> can be increased.

As shown in <FIG>, the powertrain PT is arranged in back of the front connecting member <NUM>. Specifically, the powertrain PT is arranged between the front connecting member <NUM> and the rear connecting member <NUM> in the plan view. A pair of driveshafts <NUM> to transmit an output of the powertrain PT to the right-and-left front wheels F are provided on both sides of the lower structural body <NUM>.

Further, a pair of suspension arms 13a to constitute part of the front-side suspension device <NUM> are pivotally supported at the right-and-left front frame members <NUM> via a pair of brackets 13b. The bracket 13b is provided at a connection portion of the front frame member <NUM> and the rear connecting member <NUM>.

At the lower structural body <NUM>, two left-side connection portions <NUM>, <NUM> to connect the left-side front frame member <NUM> to the left-side front side frame <NUM> (described later) are provided to be spaced apart from each other in the longitudinal direction, and two right-side connection portions <NUM>, <NUM> to connect the right-side front frame member <NUM> to the right-side front side frame <NUM> (described later) are provided to be spaced apart from each other in the longitudinal direction. These connection portions <NUM>, <NUM>, <NUM>, <NUM> can be made of a plate member, a cylindrical member, a columnar member, or the like which extend in the vertical direction. These are made of the pressing member in the present embodiment, but these may be made of the pressing member or the like. Further, the number of the left-side connection portions <NUM>, <NUM> is not limited to two, and three or more connection portions may be provided to be spaced apart from each other in the longitudinal direction. The right-side connection portions <NUM>, <NUM> are similar to the left-side connection portions <NUM>, <NUM>.

The front left-side connection portion <NUM> is provided at a connection portion of the front connecting member <NUM> to the left-side front frame member <NUM>. Specifically, the front portion of the left-side front frame member <NUM> and the left end portion of the front connecting member <NUM> are provided to overlap each other in the vertical direction, and the left end portion of the front connecting member <NUM> is connected to the front portion of the left-side front frame member <NUM>. Accordingly, the above-described connection portion is constituted by the left end portion of the front connecting member <NUM>. A lower end portion of the left-side connection portion <NUM> is attached to the left end portion of the front connecting member <NUM>.

Further, the front right-side connection portion <NUM> is provided at a connection portion of the front connecting member <NUM> to the right-side front frame member <NUM>. Specifically, the front portion of the right-side front frame member <NUM> and the right end portion of the front connecting member <NUM> are provided to overlap each other in the vertical direction, and the right end portion of the front connecting member <NUM> is connected to the front portion of the right-side front frame member <NUM>. Accordingly, the above-described connection portion is constituted by the right end portion of the front connecting member <NUM>. A lower end portion of the right-side connection portion <NUM> is attached to the right end portion of the front connecting member <NUM>.

The rear left-side connection portion <NUM> is provided at a connection portion of the left-side front frame <NUM> to the middle connecting member <NUM>. A lower end portion of the rear-side left-side connection portion <NUM> is attached to the left-side front frame member <NUM> and arranged in back of the left-side driveshaft <NUM>. Likewise, the rear-side right-side connection portion <NUM> is provided at a connection portion of the right-side front frame <NUM> to the middle connecting member <NUM>. A lower end portion of the rear-side right-side connection portion <NUM> is attached to the right-side front frame member <NUM> and arranged in back of the right-side driveshaft <NUM>. Thereby, the distance between the front-and-rear left-side connection portions <NUM>, <NUM> and the distance between the right-side connection portions <NUM>, <NUM> can be enlarged.

The right-side front frame member <NUM> is arranged on the left side (the inward side in the vehicle width direction) of the right-side front side frame <NUM> shown in <FIG>, and the left-side front frame member <NUM> is arranged on the right side (the inward side in the vehicle width direction) of the left-side front side frame <NUM> shown in <FIG>. Thereby, the distance between the left-and-right front side frames <NUM> becomes wider than the distance between the right-and-left front frame members <NUM>. The powertrain PT including the driving motor M is installed between the left-and-right front side frames <NUM>.

As shown in <FIG>, the right-side connection portions <NUM>, <NUM> are configured in an oblique shape such that their upper sides are positioned at the right side (the outward side in the vehicle width direction). This is because the right-side front side frame <NUM> is positioned on the right side of the front frame member <NUM> above the right-side front frame member <NUM>. Likewise, the left-side connection portions <NUM>, <NUM> are configured in the oblique shape such that their upper sides are positioned at the left side (the outward side in the vehicle width direction).

A pair of right-and-left rear frame members <NUM> are provided similarly to the front frame members <NUM> and extend reward substantially horizontally and straightly. The rear frame member <NUM> can be made of the extruded member, the pressing member, or the like. In the present embodiment, it is made of the extruded member.

The left-side rear frame member <NUM> is connected to a portion of the rear-end member <NUM> which constitutes a rear part of the battery case <NUM> which is positioned on the left side of a center, in the lateral direction, of the rear-end member <NUM>, and this connection portion is located on the right side of the left-side member <NUM> of the battery case <NUM>. The right-side rear frame member <NUM> is connected to a portion of the rear-end member <NUM> which is positioned on the right side of the center, in the lateral direction, of the rear-end member <NUM>, and this connection portion is located on the left side of the right-side member <NUM> of the battery case <NUM>. The connection structure of the rear frame member <NUM> to the rear-end member <NUM> can be similar to the above-described connection structure of the front frame member <NUM> to the front-end member <NUM>.

Further, in the embodiment shown in <FIG>, the front end portions of the right-and-left rear frame members <NUM> are connected to the rear-end member <NUM>, and a middle portion, in the longitudinal direction, of each of the rear frame members <NUM> is connected to the rear-end member <NUM> by a connecting member <NUM>. Thereby, part of the rear frame member <NUM> which is positioned on the side of the battery case is connected to the battery case <NUM> at plural points which are spaced apart from each other in the lateral direction.

Each of the right-and-left suspension arms 14a which constitutes part of the rear suspension device <NUM> is pivotally supported at each of the right-and-left rear frame members <NUM>.

Next, the upper structural body <NUM> will be described. As shown in <FIG>, the upper structural body <NUM> comprises the floor panel <NUM>, a dash panel <NUM>, a pair of right-and-left front side frames <NUM>, and a pair of right-and-left side sills <NUM>. <FIG> show a state where the doors, the bonnet hood, the front fender, the widow glass, the bumper, the front-and-rear lights, part of the seats, interior members, and others are removed.

The floor panel <NUM> constitutes a floor face of the cabin R1, which is made of a steel plate or the like which extends in the longitudinal direction and in the lateral direction. A space above the floor panel <NUM> is the cabin R1. A roof <NUM> is provided at an upper side of the cabin R1. As shown in <FIG>, a front opening portion 3a and a rear opening portion 3b are formed at a left-side part of the upper structural body <NUM>. As shown in <FIG>, the front opening portion 3a and the rear opening portion 3b are configured to be opened or closed by means of a front door <NUM> and a rear door <NUM>. Another front door and another rear door are arranged at a right-side part of the upper structural body <NUM> as well, not illustrated.

The dash panel <NUM> is a member which partitions the power room R3 from the cabin R1 in the longitudinal direction. The dash panel <NUM> is made of a steel plate, for example, and extends in the lateral direction and in the vertical direction. As shown in <FIG>, a pair of front wheelhouses <NUM> (only the right-side one is illustrated in these figures) which accommodate the right-and-left front wheels F are provided at right-and-left both sides of a front part of the upper structural body <NUM>. A left end portion of the dash panel <NUM> is connected to the left-side front wheelhouse portion <NUM> (shown in <FIG>), and a right end portion of the dash panel <NUM> is connected to the right-side front wheelhouse portion <NUM> (shown in <FIG>).

As shown schematically in <FIG>, the floor panel <NUM> comprises a front floor portion 70a and a rear floor portion 70b. As shown in <FIG>, the floor panel <NUM> further comprises a kickup portion 70c at its rear part. The front floor portion 70a, the rear floor portion 70b, and the kickup portion 70c may be made of a single plate member or separated plate members. In a case of the separated members, the single-sheet of floor panel <NUM> can be formed by welding the plural plate members.

As shown in <FIG>, the front floor portion 70a constitutes a front-side part of the floor panel <NUM>, which is inclined or curved such that its front side is located upward. A front end portion of the front floor portion 70a is connected to a lower end portion of the dash panel <NUM>. Accordingly, the floor panel <NUM> is provided to extend rearward from a lower end portion of the dash panel <NUM>.

The rear floor portion 70b is configured to extend rearward from a rear end portion of the front floor portion 70a, which constitutes a middle part, in the longitudinal direction, of the floor panel <NUM>. The front portion of the battery case <NUM> of the lower structural body <NUM> is positioned just below the front floor portion 70a, and the rear portion of the battery case <NUM> is positioned just below the front floor portion 70a. Accordingly, the battery case <NUM> is configured to extend from a position located below the front floor portion 70a to another position located below the rear floor portion 70b, whereby the battery B can be installed in a mostly wide area below the floor panel <NUM>.

A middle portion, in the longitudinal direction, of the floor panel <NUM> is located at a lower level than the front floor portion 70a. That is, the front floor portion 70a is provided in the front side of the rear floor portion 70b and located at a higher level than the rear floor portion 70b. At least part of a seat fixation portion <NUM> to fix the front seat S1 is attached to a front-side portion of the rear floor portion 70b. The seat fixation portion <NUM> is constituted by a bracket, for example. Herein, whole part of the seat fixation portion <NUM> may be attached to the rear floor portion 70b as long as at least a rear portion of the seat fixation portion <NUM> is attached to the rear floor portion 70b. Since the front seat S1 can be disposed at a lower level by attaching at least the rear portion of the seat fixation portion <NUM> to the rear floor portion 70b, a hip point of a front-seat passenger P can be lowered, so that there occurs a sufficient space above a head of the front-seat passenger, thereby improving the residential performance. Further, lowering of the hip point means that a sitting position of the front-seat passenger P becomes low, so that the level of the gravity center of the vehicle when the passenger is in the vehicle is lowered. In the present embodiment, since the whole part of the seat fixation portion <NUM> is attached to the rear floor portion <NUM>, the front seat S1 can be located at the further lower level.

When a driver as the front-seat passenger P is seated at the front seat S1, a heel P1 of the front-seat passenger P is placed on the front floor portion 70a. Since the front floor portion 70a where the heel P1 is placed is located at the higher level than the rear floor portion 70b, the position of the heel P1 is located at a higher level compared to an operational position of a general automotive vehicle (in which the front floor portion and the rear floor portion are located at the same level). This layout makes a position where an upper leg P2 and a lower leg P3 form a wide open angle. In <FIG>, reference character <NUM> denotes a center line of the upper leg P2, reference character <NUM> denotes a center line of the lower leg P3, and the difference in level between the front floor portion 70a and the rear floor portion 70b is set so that an angle between the center line <NUM> and the center line <NUM> (an opening angle α between the upper leg P2 and the lower leg P3) can fall within a range of <NUM> - <NUM>°.

Since the angle between the lower leg P3 and the front floor portion 70a (an angle β between the center line <NUM> and the front floor portion 70a) becomes small by setting the level deference described above, a component force, in the vertical direction, of an inputted force to the heel P1 in a pedal operation becomes small, thereby improving the operability of a brake pedal <NUM>. Specifically, when the front-seat passenger P presses down the brake pedal <NUM>, the heel P1 applies an obliquely-downward force F to the front floor portion 70a. If this force F is divided into a vertical-direction force and a horizontal-direction force, they becomes a force F1 and a force F2. Herein, since the angle β is small as described above, the vertical-direction force F1 inputted from the heel P1 becomes small. Thereby, for example, a pedal-pressing change operation from the brake pedal <NUM> to an accelerator pedal (not illustrated) or its reverse operation become so quick and accurate that the pedal operability can be improved.

Further, there is a case where a foot (feet) of a rear-seat passenger is placed on the rear floor portion 70b. Since the rear floor portion 70b is located at the lower level than the front floor portion 70a, a foot space of the rear-seat passenger is enlarged, thereby improving the residential performance.

As shown in <FIG>, the kickup portion 70c constitutes a rear-side part of the floor panel <NUM> and is connected to a rear end portion of the rear floor portion 70b. The kickup portion 70c is located at the higher level than the rear floor portion 70b, and a vertical plate portion 70d which extends in the vertical direction is provided between the kickup portion 70c and the rear floor portion 70b. The level of the kickup portion 70c is set to be higher than that of the front floor portion 70a. A rear seat S2 (shown in <FIG>) is attached onto an upper face of the kickup portion 70c. The battery B or a controller (not illustrated) or the like of the electric automotive vehicle <NUM> may be arranged below the kickup portion 70c.

A floor-side cross member <NUM> which extends in the lateral direction along the floor panel <NUM> is attached to the floor panel <NUM>. The floor-side cross member <NUM> is welded to the upper face of the rear floor panel 70b of the floor panel <NUM>, for example. A shape of the floor-side cross member <NUM> is not limited to a particular shape. In the present embodiment, this member <NUM> is configured such that it protrudes upward with its lower side opened and has a cross section whose shape is mostly similar over a whole length, in the vehicle width direction, thereof. By attaching the floor-side cross member <NUM> to the rear floor portion 70b, a closed-cross section is formed by the floor-side cross member <NUM> and the rear floor portion 70b. A left end portion of the floor-side cross member <NUM> is positioned near the inner face, in the vehicle width direction, of the left-side side sill <NUM>, and a right end portion of the floor-side cross member <NUM> is positioned near the inner face, in the vehicle width direction, of the right-side side sill <NUM>. Herein, the floor-side cross member <NUM> may be attached to a lower face of the rear floor portion 70b.

As shown in <FIG>, the right-and-left front side frames <NUM> are arranged at a vehicle-body front part, which are vehicle high-strength members extending in the longitudinal direction. <FIG> show only the right-side front side frame <NUM>, and <FIG> shows the left-side front side frame <NUM>. That is, the right-and-left front side frames <NUM> are positioned in front of the floor panel <NUM> and located at the higher level than the floor panel <NUM>, and specifically, these front side frames <NUM> are provided to extend forward from right-and-left both sides of a lower portion of the dash panel <NUM>.

The right-and-left front side frame <NUM> are arranged symmetrically in the lateral direction, which can be made of plural pressing members joined together or the extruded member. Each cross section, in a direction perpendicular to the longitudinal direction of the front side frame <NUM>, of the front side frames <NUM> is set to be larger than that of the front frame members <NUM> of the lower structural body <NUM>. Thereby, the front side frames <NUM> become the high-strength members compared to the front frame members <NUM>.

A crash can 72a, which is configured to have compressive deformation in the vehicle frontal collision so as to absorb collision energy, is attached to each front end portion of the right-and-left front side frames <NUM>. The crash can 72a is a cylindrical-shaped metal-made member which is configured to extend in the longitudinal direction. A front bumper reinforcement <NUM> extending in the lateral direction is fixed to respective front ends of the right-and-left crash cans 72a.

As shown in <FIG>, an upper portion of the right-side connection portion <NUM> which is positioned at a front side of the lower structural body <NUM> is connected to the right-side crash can 72a. Further, an upper portion of the left-side connection portion <NUM> (shown in <FIG>) which is positioned at the front side of the lower structural body <NUM> is connected to the left-side crash can 72a. Since the crash can 72a is provided at the front end portion of the front side frame <NUM>, a connection point of the left-side connection portion <NUM> can be provided near a front end of the vehicle body by connecting the upper portion of the left-side connection portion <NUM> to the crash can 72a. Thereby, the longitudinal distance between the left-side connection portions <NUM>, <NUM> can be enlarged, so that the operational effect of connecting the front frame member <NUM> to the front side frame <NUM> by the left-side connection portions <NUM>, <NUM> can be further improved. This situation is the same for the right-side connection portions <NUM>, <NUM>. Each connection structure of the left-side connection portions <NUM>, <NUM> and the right-side connection portions <NUM>, <NUM> to the floor side frames <NUM> is the one using fastening members, such as bolts and nuts, for example. Herein, the front left-side connection portion <NUM> and the front right-side connection portion <NUM> may be connected to respective portions of the front side frames <NUM> which are positioned in back of the crash cans 72a.

Further, as shown in <FIG>, a lower portion of the rear right-side connection portion <NUM> is connected to the front frame member <NUM> at a point located in back of the driveshaft <NUM>. Further, as shown in <FIG>, an upper portion of the rear right-side connection portion <NUM> is connected to a point of the front side frame <NUM> which is positioned slightly rearward from a center, in the longitudinal direction, of the front side frame <NUM>. Thereby, the longitudinal distance between the right-side connection portions <NUM>, <NUM> can be further enlarged. This situation is the same for the left-side connection portions <NUM>, <NUM>.

The right-and-left side sills <NUM> are provided to extend in the longitudinal direction at the right-and-left both end portions of the floor panel <NUM>. As shown in <FIG>, a left end portion of the floor panel <NUM> is a central portion, in the vertical direction, of the left-side side sill <NUM>, an upper-side portion of the side sill <NUM> protrudes upward from a connection portion of the floor panel <NUM> and a lower-side portion of the side sill <NUM> protrudes downward from a connection portion of the floor panel <NUM>. Since the battery case <NUM> is arranged below the floor panel <NUM>, a lower-side portion of the side sill <NUM> and the battery case <NUM> are provided to overlap each other in the vehicle side view. Likewise, the right-side side sill <NUM> is connected to a right end portion of the floor panel <NUM>.

The right-and-left side sills <NUM> are symmetrical laterally. Hereafter, the specific structure of the left-side side sill <NUM> will be described referring to <FIG>. The left-side side sill <NUM> comprises an inner member <NUM> and an outer member <NUM> which are made of the pressing member, respectively. The inner member <NUM> is a member which constitutes a cabin-inside portion of the side sill <NUM>, which is configured to protrude toward a cabin inside and extend in the longitudinal direction. The outer member <NUM> is a member which constitutes a cabin-outside portion of the side sill <NUM>, which is configured to protrude toward a cabin outside and extend in the longitudinal direction. Respective upper portions of the inner member <NUM> and the outer member <NUM> are joined, and respective lower portions of the inner member <NUM> and the outer member <NUM> are joined, whereby the side sill <NUM> having an hollow inside are formed.

A first recess portion 73a which is recessed outward, in the vehicle width direction, is provided to extend longitudinally at a lower portion of an inside, in the vehicle width direction, of the side sill <NUM>. The first recess portion 73a is opened downward and inward, in the vehicle width direction. An outward side, in the vehicle width direction, of the battery case <NUM> of the lower structural body <NUM> is configured to be fitted into the first recess portion 73a. Specifically, the left-side member <NUM> of the battery case <NUM> is configured to be inserted into the first recess portion 73a from below the first recess portion 73a. Thereby, the dimension, in the vehicle width direction, of the battery case <NUM> can be made sufficiently long and also the downward-projection quantity of the battery case <NUM> can be made properly small.

Inside the side sill <NUM> is provided a hollow-shaped side load-transmitting member <NUM> which extends in the longitudinal direction and transmits the load applied to the vehicle-inward side from the vehicle-outward side toward the vehicle-inward side. Herein, the load transmitted by the side load-transmitting member <NUM> is considered as the one which is large enough to cause deformation of the vehicle-side member of the electric automotive vehicle <NUM> in the vehicle side collision in which an obstacle hits against the vehicle <NUM> from the vehicle side.

The side load-transmitting member <NUM> which can be made of the extruded member, for example, which is continuous from a front end portion of the side sill <NUM> to a rear end portion of the side sill <NUM>. The side load-transmitting member <NUM> is fixed to the side sill <NUM> at an appropriate point. The fixation structure of the side load-transmitting member <NUM> to the side sill <NUM> is not limited but the structure using fastening members, such as bolt and nut or rivet, is applicable.

Since the side load-transmitting member <NUM> has the high rigidity so as to transmit the load toward the vehicle-inward side in the vehicle side collision, this member <NUM> is resistant against not only a compressive force but a bending force and a tortional force, and therefore this member <NUM> also serves as a reinforcing member to reinforce the side sill <NUM> and improve the vehicle-body rigidity during normal vehicle-traveling. Thus, since the side load-transmitting member <NUM> reinforces the side sill <NUM> inside the side sill <NUM>, this member <NUM> can be called an inner reinforcement.

The side load-transmitting member <NUM> comprises an upper wall portion <NUM>, an outside wall portion <NUM>, an inside upper vertical wall portion <NUM>, an inside lower vertical wall portion <NUM>, a middle wall portion <NUM>, and a lower wall portion <NUM>. The upper wall portion <NUM> extends in the vehicle width direction and is arranged near an upper end portion inside the side sill <NUM>. The outside wall portion <NUM> extends downward from an outer end portion, in the vehicle width direction, of the upper wall portion <NUM> and is arranged near an outer end portion, in the vehicle width direction, inside the side sill <NUM>. An upper end portion of the outside wall portion <NUM> is located at a higher level than an upper end portion of the floor-side cross member <NUM>. A lower end portion of the outside wall portion <NUM> is located at a lower level than an upper end portion of the second battery-side cross member 25B which is provided inside the battery case <NUM>. Herein, the positional relationship between the first battery-side cross member 25A and the third battery-side cross member 25C and the side load-transmitting member <NUM> is substantially the same as well, which is not illustrated.

The inside upper vertical wall portion <NUM> extends downward from an inner end portion, in the vehicle width direction, of the upper wall portion <NUM> and is arranged near an inner end portion, in the vehicle width direction, inside the side sill <NUM>. An upper end portion of the inside upper vertical wall portion <NUM> is located at a higher level than the upper end portion of the floor-side cross member <NUM>. A lower end portion of the inside upper vertical wall portion <NUM> is located at a lower level than the rear floor portion 70b and at an upper level than the upper end portion of the second battery-side cross member 25B.

The middle wall portion <NUM> extends outward, in the vehicle width direction, from the lower end portion of the inside upper vertical wall portion <NUM>. An outer end portion, in the vehicle width direction, of the middle wall portion <NUM> is positioned slightly on an inward side of a center, in the vehicle width direction, of the upper wall portion <NUM>. The inside lower vertical wall portion <NUM> extends downward from an inner end portion, in the vehicle width direction, of the middle wall portion <NUM>. A lower end portion of the inside lower vertical wall portion <NUM> is located at a lower level than the upper end portion of the second battery-side cross member 25B. The vertical dimension of the inside lower vertical wall portion <NUM> is set to be shorter than that of the inside upper vertical wall portion <NUM>.

A second recess portion 120a which is recessed outward, in the vehicle width direction, is formed at a lower portion of a cabin-inside of the side load-transmitting member <NUM> by the inside lower vertical wall portion <NUM> and the middle wall portion <NUM> such that it corresponds to the above-described first recess portion 73a of the side sill <NUM>. The portion of the side sill <NUM> where the first recess portion 73a is formed is configured to be fitted into the second recess portion 120a of the side load-transmitting member <NUM>.

The lower wall portion <NUM> extends from the lower end portion of the inside lower vertical wall portion <NUM> to the lower end portion of the outside wall portion <NUM>. The vehicle-width-direction dimension of the lower wall portion <NUM> is set to be longer than that of the middle wall portion <NUM>.

In the vehicle side view, an upper-side portion of the side load-transmitting member <NUM> overlaps the floor-side cross member <NUM>, and a lower-side portion of the side load-transmitting member <NUM> overlaps the second battery-side cross member 25B. That is, the side load-transmitting member <NUM> overlaps the floor-side cross member <NUM> in the vehicle side view, and comprises the inside upper vertical wall portion (first vertical wall portion) <NUM> which extends in the vertical direction and the inside lower vertical wall portion (second vertical wall portion) <NUM> which overlaps the battery case <NUM> in the vehicle side view and extends in the vertical direction. Herein, a lower portion of the inside upper vertical wall portion <NUM> may be configured to overlap an upper portion of the battery case <NUM>.

First - fourth ribs <NUM> - <NUM> are integrally formed at the inside of the side load-transmitting member <NUM>. The first rib <NUM> extends in the vehicle width direction at a point which is upward spaced apart from the middle wall portion <NUM>, and an inner end portion, in the vehicle width direction, of the first rib <NUM> is connected to a central portion, in the vertical direction, of the inside upper vertical wall portion <NUM>. The first rib <NUM> is inclined such that its outside is located at a higher level.

The second rib <NUM> extends in the vehicle width direction at a point which is downward spaced apart from the first rib <NUM>, and an inner end portion, in the vehicle width direction, of the second rib <NUM> is connected to an upper end portion of the inside lower vertical wall portion <NUM>. An outer end portion, in the vehicle width direction, of the second rib <NUM> is connected to a central portion, in the vertical direction, of the outside wall portion <NUM>. The first rib <NUM> and the second rib <NUM> may be provided to extend mostly horizontally or be inclined such that its inside is located at a higher level or its outside is located at a higher level.

The third rib <NUM> extends upward from the upper end portion of the inside lower vertical wall portion <NUM>. An upper end portion of the third <NUM> is connected to a central portion, in the vertical direction, of the upper wall portion <NUM>. The third rib <NUM> is inclined such that its upper side is positioned on the further outward side. An outer end portion, in the vehicle width direction, of the first rib <NUM> is connected to a central portion, in the vertical direction, of the third rib <NUM>.

The fourth rib <NUM> extends in the vehicle width direction at a point which is upward spaced apart from the second rib <NUM>. An inner end portion, in the vehicle width direction, of the fourth rib <NUM> is connected to the central portion, in the vertical direction, of the third rib <NUM>. An outer end portion, in the vehicle width direction, of the fourth rib <NUM> is connected to the central portion, in the vertical direction, of the outside wall portion <NUM>. The inner end portion, in the vehicle width direction, of the fourth rib <NUM> and the outer end portion, in the vehicle width direction, of the first rib <NUM> are connected via the third rib <NUM>, and a single rib which is continuous in the vehicle width direction is constituted by the first rib <NUM> and the fourth rib <NUM>. The number or shape of the ribs provided inside the side load-transmitting member <NUM> are not limited to the above-described ones. The number of the ribs may be three or less, or five or more.

The battery case <NUM> is fixed to the side sill <NUM> and also fixed directly to the side load-transmitting member <NUM>. Plural metal-made cylindrical members <NUM> which extend in the vertical direction are fixed to the left-side member <NUM> of the battery case <NUM>. The longitudinal distance between the plural cylindrical members <NUM> can be set at about tens of centimeters, for example. As shown in <FIG>, the plural cylindrical members <NUM> are provided to be spaced apart from each other in the longitudinal direction. A bolt <NUM> is inserted into each of the cylindrical members <NUM> from below.

Meanwhile, an opening where a shaft portion of the bolt <NUM> are inserted is formed at a portion of the side sill <NUM> which corresponds to an inner face of the first recess portion 73a. Likewise, the middle wall portion <NUM> of the side load-transmitting member <NUM> has an opening where the shaft portion of the bolt <NUM> is inserted. These both openings match each other. A nut <NUM> is stored inside the side load-transmitting member <NUM>. The nut <NUM> is fixed to an upper face of the middle wall portion <NUM> of the side load-transmitting member <NUM>. The number and position of the openings and the nuts <NUM> match those of the cylindrical members <NUM>.

Accordingly, by inserting the bolts <NUM> into the cylindrical members <NUM> and subsequently into the opening of the side sill <NUM> and the opening of the side load-transmitting member <NUM> such that the bolts <NUM> are threaded in the nuts <NUM>, plural points of the left side of the battery case <NUM> can be fixed to the side load-transmitting member <NUM> and the side sill <NUM>. The right side of the battery case <NUM> can be fixed similarly.

While the present embodiments describes a case where the side load-transmitting member <NUM> is formed integrally, the side load-transmitting member <NUM> may be formed by combining plural members. For example, an inside part, in the vehicle width direction, of the side load-transmitting member <NUM> and an outside part, in the vehicle width direction, of the side load-transmitting member <NUM> are formed separately, and then these parts are assembled together, which is not illustrated. Thus, the side load-transmitting member <NUM> can be constituted as a two-split structure. Further, a three-split structure is appliable as well.

As shown in <FIG> and others, the upper structural body <NUM> comprises a pair of right-and-left hinge pillars <NUM>. The right-side hinge pillar <NUM> extends upward from a front end portion of the right-side side sill <NUM>. Further, as shown in <FIG>, the left-side hinge pillar <NUM> extends upward from a front end portion of the left-side side sill <NUM>. Right-and-left front doors <NUM> (shown in <FIG>) are respectively attached to the right-and-left hinge pillars <NUM>.

Further, as shown in <FIG>, the upper structural body <NUM> comprises a pair of right-and-left center pillars <NUM>. The right-side center pillar <NUM> extends upward from a central portion, in the longitudinal direction, of the right-side side sill <NUM>. Moreover, as shown in <FIG>, the left-side center pillar <NUM> extends upward from a central portion, in the longitudinal direction, of the left-side side sill <NUM>. The right-and-left rear doors <NUM> (shown in <FIG>) are respectively attached to the right-and-left center pillars <NUM>.

As shown in <FIG>, the upper structural body <NUM> comprises a pair of right-and-left floor reinforcements (first longitudinal load-transmitting members) <NUM>. The floor reinforcement <NUM> extends in the longitudinal direction along the upper face of the front floor portion 70a. A front end portion of the right-side floor reinforcement <NUM> is connected to a rear end portion of the right-side front side frame <NUM>. A rear end portion of the right-side floor reinforcement <NUM> is connected to a front end portion of the right-side side sill <NUM>. Accordingly, since the front side frame <NUM> and the side sill <NUM> are connected by the floor reinforcement <NUM>, when the collision load is inputted to the front side fame <NUM> in the vehicle frontal collision, for example, this collision load is transmitted to the side sill <NUM> via the floor reinforcement <NUM>.

The floor reinforcement <NUM> is configured such that it protrudes upward with its lower side opened, and this protrusion shape is continuous over its whole length from a front end portion to a rear end portion of the floor reinforcement <NUM>. A closed-cross section is formed by the floor reinforcement <NUM> and the front floor portion 70a by attaching the floor reinforcement <NUM> to the upper face of the front floor portion 70a.

Since the side sill <NUM> is positioned on the outward side, in the vehicle width direction, of the front side frame <NUM>, the floor reinforcement <NUM> extends, curving in the plan view, such that its rear side is positioned further outward, in the vehicle width direction. This curve shape of the floor reinforcement <NUM> matches a shape of a lower end portion of the front wheelhouse portion <NUM>. That is, the floor reinforcement <NUM> extends along the lower end portion of the front wheelhouse portion <NUM> and is connected integrally to the front wheelhouse <NUM>. Herein, the left-side floor reinforcement (not illustrated) is laterally-symmetrical to the right-side one.

Further, in the plan view, a portion (rear end portion) of the right-side floor reinforcement <NUM> which is positioned on the side of the side sill <NUM> and a portion (rear end portion) of the right-side outside connection portion <NUM> which is positioned on the side of the battery case <NUM> overlap each other. Since the rear end portion of the floor reinforcement <NUM> is the portion connected to the side sill <NUM>, this rear end portion is arranged adjacently to the side sill <NUM>. Meanwhile, since the outside connection portion <NUM> is the member connected to the battery case <NUM>, this portion <NUM> is separated from the side sill <NUM>. However, overlapping of the rear end portion of the outside connection portion <NUM> and the rear end portion of the floor reinforcement <NUM> in the plan view means that the rear end portion of the outside connection portion <NUM> can be made close to the side sill <NUM>. Accordingly, the collision load from the vehicle-front side can be securely applied toward the side sill <NUM> through the outside connection portion <NUM>. This situation is the same for the left-side structure.

A rear end portion of the right-side floor reinforcement <NUM> and a base end portion (lower end portion) of the right-side hinge pillar <NUM> are arranged at the same position in the longitudinal direction. That is, a portion of the side sill <NUM> which is positioned near the base end portion of the hinge pillar <NUM> has the high rigidity in particular, so that by connecting the rear end portion of the floor reinforcement <NUM> to this high-rigidity portion, the collision load can be efficiently absorbed by the side sill <NUM>.

As shown in <FIG>, the upper structural body <NUM> comprises a pair of right-and-left lower load-transmitting members (second longitudinal load-transmitting members) <NUM>. The lower load-transmitting member <NUM> is arranged above the front flame member <NUM> of the lower structural body <NUM>, and the front frame member <NUM> and the lower load-transmitting member <NUM> are spaced apart from each other in the vertical direction. Further, the lower load-transmitting member <NUM> extends in the longitudinal direction along a lower face of the front floor portion 70a. As schematically shown in <FIG>, a front end portion of the right-side lower load-transmitting member <NUM> is connected to a rear end portion of the right-side front side frame <NUM>. Herein, since the lower load-transmitting member <NUM> extends toward the front portion of the battery case <NUM>, when the collision load of the vehicle frontal collision is inputted to the front side frame <NUM> toward the vehicle rear side, for example, this collision load is transmitted to the front portion of the battery case <NUM> through the lower load-transmitting member <NUM>. The left-side lower load-transmitting member <NUM> is laterally symmetrical to the right-side one.

The lower load-transmitting member <NUM> is configured such that it protrudes downward with its upper side opened, and this protrusion shape is continuous over its whole length from a front end portion to a rear end portion of the lower load-transmitting member <NUM>. A closed-cross section is formed by the lower load-transmitting member <NUM> and the front floor portion 70a by attaching the lower load-transmitting member <NUM> to the lower face of the front floor portion 70a.

A rear portion of the right-side lower load-transmitting member <NUM> is located at a position inside the battery case <NUM> which is located on the right side of the front center member <NUM> and on the left side of the right-side member <NUM>. Further, a rear portion of the left-side lower load-transmitting member <NUM> is located at a position inside the battery case <NUM> which is located on the left side of the front center member <NUM> and on the right side of the left-side member <NUM>.

As shown in <FIG>, a cross member <NUM> which extends in the lateral direction and interconnects the rear portion of the left-side lower load-transmitting member <NUM> and the rear portion of the right-side lower load-transmitting member <NUM> is provided at the lower face of the front floor portion 70a. The cross member <NUM> is configured such that it protrudes downward with its upper side opened and has a cross section whose shape is mostly similar over a whole length, in the vehicle width direction, thereof. By attaching the cross member <NUM> to the lower face of the front floor portion 70a, a closed-cross section is formed by the cross member <NUM> and the front floor portion 70a. The rear portion of the lower load-transmitting member <NUM> can be suppressed from being displaced in the lateral direction by providing the cross member <NUM> when the right-and-left lower load-transmitting members <NUM> receive the collision load of the vehicle frontal collision.

As shown in <FIG>, the front-end member <NUM> which constitutes the front portion of the battery case <NUM> is arranged just below the cross member <NUM>. The front-end member <NUM> is fastened to the cross member <NUM> by bolts and nuts (not illustrated). This fastening structure of the front-end member <NUM> can be the same as that of the left-side member <NUM> to the side sill <NUM>.

A protrusion portion 22a which protrudes upward is provided at the front portion of the battery case <NUM>. Specifically, the protrusion portion 22a is provided at a portion of the front-end member <NUM> which is positioned in back of the cross member <NUM>. This protrusion portion 22a is located on the rear side of the rear portion of the lower load-transmitting member <NUM>. Further, an upper end portion of the protrusion portion 22a is located at the higher level than a lower face of the cross member <NUM> and located at the higher level than a lower face of the rear portion of the lower load-transmitting member <NUM>. Thereby, the cross member <NUM> and the lower load-transmitting member <NUM> overlaps the protrusion portion 22a in a longitudinal view. The protrusion portion 22a is a portion where the collision load is transmitted from the lower load-transmitting member <NUM> when the lower load-transmitting member <NUM> is retreated by the collision load in the vehicle frontal collision.

The protrusion portion 22a extends continuously in the lateral direction. That is, while it may be considered that the rear portion of the lower load-transmitting member <NUM> is displaced laterally in the vehicle frontal collision, since the protrusion portion 22a is continuous in the lateral direction, the collision load is securely inputted to the protrusion portion 22a even if the rear portion of the lower load-transmitting member <NUM> is displaced in the lateral direction. Herein, the protrusion portion 22a is not limited to this one configured to be continuous in the lateral direction, but any protrusion portion which is configured to be discontinuous may be applicable as long as its part overlaps the rear portion of the lower load-transmitting member <NUM> in the longitudinal view.

The protrusion portion 22a may be formed integrally with or separated from the front-end member <NUM>. In a case where the front-end member <NUM> is the extruded member, the protrusion portion 22a can be integrated easily. The protrusion portion 22a may be fixed to the bottom plate <NUM>, for example, or fixed to the left-side member <NUM>, the right-side member <NUM>, or the like. The protrusion portion 22a may be of a plate shape (rib shape), a bar shape, a cylindrical shape, or the like. The reinforcing effect of the front-end member <NUM> can be obtained by forming the rib-shaped protrusion portion 22a integrally with the front-end member <NUM>.

The rear portion of the lower load-transmitting member <NUM> and the protrusion portion 22a are arranged such that they are spaced apart from each other in the longitudinal direction, having a specified distance therebetween. Thereby, since the lower load-transmitting member <NUM> and the protrusion portion 22a do not contact each other during the normal vehicle-traveling, an interference noise or the like are prevented from being generated. Meanwhile, since the rear portion of the lower load-transmitting member <NUM> contacts the protrusion portion 22a when the lower load-transmitting member <NUM> moves rearward in the vehicle frontal collision, the collision load is securely inputted to the protrusion portion. That is, the above-described specified distance is set such that the lower load-transmitting member <NUM> and the protrusion portion 22a do not contact each other during the normal vehicle-traveling but the rear portion of the lower load-transmitting member <NUM> contacts the protrusion portion 22a in the vehicle frontal collision. This distance can be set at several mm - several cm, for example. Herein, the rear portion of the lower load-transmitting member <NUM> and the protrusion portion 22a may be configured to contact each other. Further, the rear portion of the lower load-transmitting member <NUM> and the protrusion portion 22a may be connected by a fastening member.

In the embodiment shown in <FIG>, the front enter member <NUM> inside the battery case <NUM> is provided below the front floor portion 70a, and its height is higher than the first - third rear center members <NUM> - <NUM>. Accordingly, since the vertical dimension of the front center member <NUM> becomes long, the front center member <NUM> having a large cross section is positioned at the front portion of the battery case <NUM>. Thereby, the battery case <NUM> can be suppressed from being deformed when receiving the collision load transmitted from the lower load-transmitting member <NUM> at its front portion.

As shown in <FIG>, the rear portion of the battery case <NUM> and the upper structural body <NUM> are connected by a connecting member <NUM>. The structure of the rear side of the upper structural body <NUM> will be described before describing this connection structure. Rear wheelhouse portions <NUM> (only the right one is illustrated in <FIG>) which accommodate the right-and-left rear wheels R are provided at right-and-left both sides of a rear portion of the upper structural body <NUM>. A baggage-room floor portion 70e which constitutes a floor face of the baggage room R2 extends rearward from a rear portion of the kickup portion 70c and is located at a higher level than the rear floor portion 70b. The rear floor portion 70b is referred to as a first floor portion, and the kickup portion 70c and the baggage-room floor portion 70e are referred to as a second floor portion which are relatively high. A left end portion of the baggage-room floor portion 70e is connected to a lower portion of the left-side rear wheelhouse portion <NUM> (shown in <FIG>), and a right end portion of the baggage-room floor portion 70e is connected to the right-side rear wheelhouse portion <NUM> (shown in <FIG>).

As shown in <FIG>, a rear cross member (first cross member) <NUM> which extends in the lateral direction is attached to a lower face of the kickup portion 70c. The rear cross member <NUM> is configured such that it protrudes downward and is opened upward, wherein its protrusion shape is continuous over its width from a left end portion to a right end portion. A closed-cross section is formed by the rear cross member <NUM> and the kickup portion 70c by attaching the rear cross member <NUM> to a lower face of the kickup portion 70c.

A rear-floor-side cross member <NUM> which extends in the lateral direction just above the rear cross member <NUM> is attached to an upper face of the kickup portion 70c. The rear-floor-side cross member <NUM> is configured such that it protrudes upward and is opened downward, wherein its protrusion shape is continuous over its width from a left end portion to a right end portion. A closed-cross section is formed by the rea-floor-side cross member <NUM> and the kickup portion 70c by attaching the rear-floor-side cross member <NUM> to an upper face of the kickup portion 70c.

Further, a right end portion of the rear-floor-side cross member <NUM> is connected to the right-side rear wheelhouse portion <NUM>, and a left end portion of the rear-floor-side cross member <NUM> is connected to the left-side rear wheelhouse portion <NUM>. Further, a lower end portion of a side-portion reinforcement <NUM> which extends upward along the right-side rear wheelhouse portion <NUM> is connected to the right end portion of the rear-floor-side cross member <NUM>. Moreover, a left end portion of a side-portion reinforcement (not illustrated) which extends upward along the left-side rear wheelhouse portion <NUM> is connected to the left end portion of the rear-floor-side cross member <NUM>. An upper portion of the right-side side-portion reinforcement <NUM> and an upper portion of the left-side side-portion reinforcement are connected by a connecting member <NUM> (shown in <FIG> and <FIG>) which extends in the lateral direction. That is, a ring-shaped structure is formed by the rear-floor-side cross member <NUM>, the right-and-left side-portion reinforcements <NUM>, and the connecting member <NUM>. This ring-shaped structure may be formed by using a reinforcement (not illustrated) which is provided up to the side of the roof <NUM>.

Meanwhile, as shown in <FIG>, the battery case <NUM> comprises a case-side cross member (second cross member) <NUM> (illustration is omitted in <FIG>). The case-side cross member <NUM> extends in the lateral direction and is attached to the rear-end member <NUM> which constitutes the rear portion of the battery case <NUM>. The case-side cross member <NUM> is located above the rear-end member <NUM>. The case-side cross member <NUM> and the rear cross member <NUM> are provided to face each other in the vertical direction.

As shown in <FIG>, the connecting member <NUM> is the one to connect the rear-end member <NUM> of the battery case <NUM> and the kickup portion 70c. Thereby, since the kickup portion 70c is reinforced by using the battery case <NUM>, the rigidity of the kickup portion 70c is improved. This rigidity improvement of the kickup portion 70c causes improvement of the whole rigidity of the floor panel <NUM>. While the connecting member <NUM> is formed by a plate member which extends in the lateral direction and in the vertical direction in the present embodiment, a member having a closed-cross section extending vertically or obliquely, a shaft-shaped member, a cylindrical member, or the like is applicable instead of the plate member. Further, the connecting member <NUM> may be constituted by plural members.

An upper portion of the connecting member <NUM> is fixed to a lower portion of the rear cross member <NUM>. Thereby, the battery case <NUM> and the kickup portion 70c are connected via the rear cross member <NUM> by the connecting member <NUM>. That is, since the upper portion of the connecting member <NUM> can be fixed to a portion where the rigidity is improved by providing the rear cross member <NUM>, fixation strength of the connecting member <NUM> fixed to the kickup portion 70c can be increased. The fixation structure of the upper portion of the connecting member <NUM> can be constituted by a detachable fastening structure using a fastening member, such as bolts and nuts (not illustrated), for example. Herein, the upper portion of the connecting member <NUM> may be directly connected to the kickup portion 70c.

Further, a lower portion of the connecting member <NUM> is fixed to the case-side cross member <NUM> which constitutes part of the battery case <NUM>. Thereby, since the lower portion of the connecting member <NUM> can be fixed to a portion of the battery case <NUM> where the rigidity is improved, fixation strength of the connecting member <NUM> fixed to the battery case <NUM> can be increased. Herein, the lower portion of the connecting member <NUM> may be detachably fixed to the battery case <NUM> by the above-described fastening member. The connecting member <NUM> may be a member positioned on the side of the upper structural body <NUM> or a member positioned on the side of the lower structural body <NUM>.

<FIG> is a schematical view showing positional relationship among cross members of the upper structural body <NUM> and the lower structural body <NUM> according to a modified embodiment. First - third floor-side cross members 110A, 110B, 110C extending in the vehicle width direction are attached to the upper face of the floor panel <NUM> of the upper structural body <NUM>, and the cross member <NUM> is attached to the lower face of the floor panel <NUM>. Since the cross member <NUM> is attached to the floor panel <NUM>, this member is a floor-side cross member.

The first floor-side cross member 110A is the above-described cross member <NUM> and provided to be spaced rearward apart from the cross member <NUM>. The second floor-side cross member 110B is spaced rearward apart from the first floor-side cross member 110A. The third floor-side cross member 110C is spaced rearward apart from the second floor-side cross member 110B. Meanwhile, the above-described first - third battery-side cross members 25A, 25B, 25C are provided at the battery case <NUM> of the lower structural body <NUM>. The cross member <NUM>, the first - third floor-side cross members 110A, 110B, 110C, and the first - third battery-side cross members 25A, 25B, 25C overlap the side sill <NUM> (shown in <FIG> and others) in the side view.

The cross member <NUM>/the first - third floor-side cross members 110A, 110B, 110C and the first - third battery-side cross members 25A, 25B, 25C are offset from each other in the vehicle longitudinal direction in the vehicle side view. That is, the cross member <NUM>, 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 order from the vehicle front side to the vehicle rear side, and the cross member <NUM>, the first - third floor-side cross members 110A, 110B, 110C and the first - third battery-side cross members 25A, 25B, 25C are provided alternately in the longitudinal direction.

For example, regarding the first floor-side cross member 110A and the second floor-side cross member 110B, the second battery-side cross member 25B is positioned in front of the first floor-side cross member 110A and in back of the second floor-side cross member 110B. Meanwhile, regarding the first battery-side cross member 25A and the second battery-side cross member 25B, the first floor-side cross member 110A is positioned in back of the first battery-side cross member 25A and in front of the second battery-side cross member 25B. This positional relationship is referred to as "being offset in the vehicle longitudinal direction.

Herein, this "being offset in the vehicle longitudinal direction" may include another embodiment. For example, an embodiment where a center, in the longitudinal direction, of the first floor-side cross member 110A and a center, in the longitudinal direction, of the second battery-side cross member 25B are offset from each other in the longitudinal direction can be included. This case includes the embodiment shown in <FIG>, and also an embodiment where a rear portion of the first floor-side cross member 110A and a front portion of the second battery-side cross member 25B overlap each other in the plan view is included.

Further, an embodiment where a front portion of the first floor-side cross member 110A is positioned in front of a front portion of the second battery-side cross member 25B and another embodiment where a rear portion of the second battery-side cross member 25B is positioned in back of a rear portion of the first floor-side cross member 110A, for example, are included in the "being offset in the vehicle longitudinal direction" as well.

The collision load of the vehicle side collision can be received by the cross member <NUM>/the first - third floor-side cross members 110A, 110B, 110C and the first - third battery-side cross members 25A, 25B, 25C. Since the cross member <NUM>/the first - third floor-side cross members 110A, 110B, 110C and the first - third battery-side cross members 25A, 25B, 25C are offset from each other in the vehicle longitudinal direction as described above, even if the obstacle is a slender object like a pole, for example, the collision load of the obstacle can be inputted to any of the floor-side cross members <NUM>, 110A, 110B, 110C and the battery-side cross members 25A, 25B, 25C.

In the vehicle side view, only the floor-side cross members 110A, 110B, 110C and the battery-side cross members 25A, 25B, 25C, which are located in nonoverlap area with the hinge pillar <NUM> (shown by an imaginary line in <FIG>), are offset in the longitudinal direction. That is, the floor-side cross members 110A, 110B, 110C and the battery-side cross members 25A, 25B, 25C, which are positioned in back of the hinge pillar <NUM> are offset in the longitudinal direction. That is, since an area where the hinge pillar <NUM> is provided has the higher strength against the collision load inputted from the side, the collision load can be received by the hinge pillar <NUM> even if the floor-side cross members and the battery-side cross members are not offset in the longitudinal direction.

Likewise, only the floor-side cross members 110A, 110B, 110C and the battery-side cross members 25A, 25B, 25C, which are located in an nonoverlap area with the center pillar <NUM>, may be offset in the longitudinal direction in the vehicle side view.

Next, the case where the electric automotive vehicle <NUM> which is configured as described above has the frontal collision will be described. The collision load of the vehicle frontal collision is inputted to the right-and-left front side frames <NUM> through the front bumper reinforcement <NUM>. Further, the collision load of the vehicle frontal collision is inputted to the right-and-left front frame members <NUM> as well.

Since the front frame member <NUM> is configured such that the plural points, in the longitudinal direction, of the front frame member <NUM> are connected to the left-side front side frame <NUM> by the left-side connection portions <NUM>, <NUM>, respectively, the left-side front frame member <NUM> where the collision load is inputted becomes stable, so that this member <NUM> is suppressed from being easily inclined in the lateral direction or in the vertical direction. This situation is the same for the right-side front frame member <NUM>. Thereby, the collision load is straightly transmitted to the front portion of the battery case <NUM> through the right-and-left front frame members <NUM>.

Herein, since the front frame member <NUM> is connected to the battery case <NUM> at the plural points which are spaced apart from each other in the lateral direction by the outside connection portion <NUM> and the inside connection portion <NUM>, the collision load inputted to the front fame member <NUM> is inputted to the plural points, in the lateral direction, of the battery case <NUM>. Since the battery case <NUM> comprises the front center member <NUM>, the left-side member <NUM>, and the right-side member <NUM> which extend in the longitudinal direction, the collision load inputted to the plural points which are spaced apart from each other in the lateral direction is dispersed to the front center member <NUM>, the left-side member <NUM>, and the right-side member <NUM>. Thereby, the collision load can be absorbed by positively using the battery case <NUM>, so that the absorption quantity of the collision load by means of the lower structural body <NUM>. Consequently, the weight reduction of the vehicle can be attained by optimizing the strength of the front side frame <NUM> and the strength of the members positioned near the rear end portion of the front side frame <NUM>.

Further, the collision load inputted to the front side frame <NUM> is transmitted to the side sill <NUM> through the floor reinforcement <NUM>. Moreover, since the outside connection portion <NUM> extends toward the side sill <NUM>, the collision load inputted to the front frame member <NUM> can be also applied toward the side sill <NUM> through the outside connection portion <NUM>. Herein, since the front reinforcement <NUM> and the outside connection portion <NUM> are spaced apart from each other in the vertical direction, a route of the collision load where the collision load is transmitted from the front side frame <NUM> to the side sill <NUM> is different from another route of the collision load where the collision load is transmitted from the front frame member <NUM> to the side sill <NUM>. Accordingly, the collision load is transmitted to the side sill <NUM> through the plural routes. This side sill <NUM> is a member which has the high rigidity among the members constituting the vehicle body, in particular, so that the collision load can be absorbed by the side sill <NUM>.

Further, the collision load inputted to the front side frame <NUM> is transmitted to the battery case <NUM> from the rear portion of the front side frame <NUM> through both of the floor reinforcement <NUM> and the lower load-transmitting member <NUM>. Thereby, since another route of the collision load where the collision load is transmitted to the battery case <NUM> through the lower load-transmitting member <NUM> is formed as well, the collision load is dispersed and absorbed by the side sill <NUM> and the battery case <NUM>. Moreover, since the floor reinforcement <NUM> and the lower load-transmitting member <NUM> extend along the floor panel <NUM>, part of the collision load inputted to the floor reinforcement <NUM> and the lower load-transmitting member <NUM> is also transmitted to the floor panel <NUM> and absorbed by the floor panel <NUM>.

Herein, while the large collision load is inputted to either of the right side and the left side in a case of an offset frontal collision of the vehicle, the present embodiment is effective in this case as well. Further, since the rear frame member <NUM> is provided, the same operational effect can be obtained even in a case of the vehicle rear collision.

Next, the case where the electric automotive vehicle <NUM> which is configured as described above has the side collision will be described. The collision load of the vehicle side collision is inputted to the side sill <NUM> from the outward side, in the vehicle width direction, of the vehicle body toward the inward side, in the vehicle width direction, of the vehicle body. Since the side load-transmitting member <NUM> is provided inside the side sill <NUM>, the collision load is inputted to the side load-transmitting member <NUM> from the outward side, in the vehicle width direction, of the vehicle body toward the inward side, in the vehicle width direction, of the vehicle body. Herein, since the inside upper vertical wall portion <NUM> of the side load-transmitting member <NUM> overlaps the cross members <NUM>, <NUM> positioned on the floor side and the inside lower vertical wall portion <NUM> of the side load-transmitting member <NUM> overlaps the battery case <NUM>, the collision load is dispersed and transmitted to the cross members <NUM>, <NUM> positioned on the floor side and the battery case <NUM>. Since the cross members <NUM>, <NUM> positioned on the floor side extend in the vehicle width direction in a state where these are attached to the floor panel <NUM>, a resistant force against the load applied from the vehicle side is large. Thereby, part of the collision load is absorbed and the collision load inputted to the battery case <NUM> is reduced, so that the battery B can be protected. Moreover, since the first - third battery-side cross members 25A, 25B, 25C, the front-end member <NUM>, and the rear-end member <NUM> are provided at the battery case <NUM>, the collision load can be absorbed by the battery case <NUM> as well.

Further, when the obstacle like the pole, for example, hits against the vehicle from the vehicle side, since the cross member <NUM>/the floor-side cross members 110A, 110B, 110C and the first - third battery-side cross members 25A, 25B, 25C are offset from each other in the vehicle longitudinal direction as shown in <FIG>, the collision load can be inputted to any of these cross members. Herein, it may be considered that a slender pole hits between the first floor-side cross member 110A and the second battery-side cross member 25B. In this case, after the side load-transmitting member <NUM> having the high strength receives the collision load of this pole, the collision load can be dispersed and absorbed by at least the first floor-side cross member 110A and the second battery-side cross member 25B.

Moreover, in a case where the obstacle is a pole having the large diameter, the automobile, or the like, the collision load is inputted to both of the floor-side cross members 110A, 110B, 110C and the first - third battery-side cross members 25A, 25B, 25C, so that the collision load can be dispersed and transmitted to the floor panel <NUM> and the battery case <NUM>.

The present invention should not be limited to the above-described embodiments, and any other modifications or improvements may be applied within the scope of the invention, which is solely defined by the appended claims.

Claim 1:
A vehicle-body structure (A) of an electric automotive vehicle (<NUM>), in which a motor for vehicle driving (M) is provided and a battery case (<NUM>) where a battery (B) to supply electric power to the motor for vehicle driving (M) is stored is arranged below a floor panel (<NUM>),
wherein said floor panel (<NUM>) comprises a first floor portion (70b) and a second floor portion (70c, 70e) located at a higher level than said first floor portion (70b), and a connecting member (<NUM>) connecting said battery case (<NUM>) and said second floor portion (70c, 70e) is provided, characterized in that
a first cross member (<NUM>) extending in a vehicle width direction is attached to a lower face of said second floor portion (70c, 70e), an upper portion of said connecting member (<NUM>) is fixed to said first cross member (<NUM>), and said battery case (<NUM>) and said second floor portion (70c, 70e) are connected via said first cross member (<NUM>) by said connecting member (<NUM>),
wherein said battery case (<NUM>) comprises a second cross member (<NUM>) extending in the vehicle width direction, and a lower portion of said connecting member (<NUM>) is fixed to said second cross member (<NUM>),
wherein said first cross member (<NUM>) and said second cross member (<NUM>) are provided to face each other in a vertical direction,
wherein the connecting member (<NUM>) is formed by a plate member which extends in the lateral direction and in the vertical direction.