ELECTRIC AUTOMOBILE

BACKGROUND OF THE INVENTION

The present invention relates to an electric automobile comprising a motor to drive a driving wheel and a battery to supply electric power to the motor.

In the electric automobile with the motor to drive the driving wheel, the traveling distance is greatly affected by the installation quantity of the battery to supply the electric power to the motor. In a case of an electric automobile disclosed in Japanese Patent Laid-Open Publication No. 2011-195056, for example, a battery is installed in a tunnel portion formed at a floor panel and also below a rear seat, thereby increasing the installation quantity of the battery. Since the battery installed in the tunnel portion of the floor panel is elongated in a longitudinal direction because of a longitudinally-long shape of the tunnel portion, the size, in a vertical direction, of a front-end portion of the battery is longer than that, in the vertical direction, of a middle portion (longitudinally middle portion) of the battery. Meanwhile, since the rear seat is long in a lateral direction, the battery installed below the rear seat is designed such that it has a laterally-long shape so as to enlarge the battery volume (capacity).

Further, Japanese Patent Laid-Open Publication No. 2008-155828 discloses a structure in which a protrusion portion is formed at a portion of a floor panel which is positioned on an assistant-driver's-seat side (passenger-seat side) and a battery is arranged inside the protrusion portion.

Herein, it is generally known that it is preferable that the longitudinal weight balance of a vehicle be equalized or a heavy object be positioned at a center, in the longitudinal direction, of the vehicle as much as possible, so that the steering stability and the kinetic performance of the vehicle can be improved. Accordingly, in designing the automobile, the equalization of the longitudinal weight balance of the vehicle and the positioning of the heavy object at the longitudinal center tend to be emphasized.

Since the motor is a heavy object in the case of the electric automobile, the motor greatly affects the longitudinal weight balance of the vehicle. Further, since the battery is another heavy object and thereby the longitudinal weight balance of the vehicle is affected considerably, the installation position of the battery need to be paid attention to as well.

According to the above-described first patent document, however, the motor to drive the driving wheel is installed at a front side of a vehicle body and the size, in the vertical direction, of the front-end portion of the battery installed in the tunnel portion of the floor panel is long. Therefore, the front-end portion of the battery becomes relatively heavy, so that there is a concern that the longitudinal weight balance of the vehicle may become too forward due to these two reasons.

Moreover, the large-volume (capacity) battery with a laterally-long shape is installed below the rear seat in the above-described first patent document. Accordingly, the battery below the rear seat comes to be located at a position which is rearward away from the center, in the longitudinal direction, of the vehicle. Thus, this structure may cause a layout where it is difficult to position the heavy object near at the center, in the longitudinal direction, of the vehicle. Therefore, there is room for improvement in the steering stability and the kinetic performance regarding the structure disclosed in the above-described first patent document.

Meanwhile, while the battery is installed inside the protrusion portion positioned on the assistant-driver's-seat side in the above-described second patent document, the longitudinal weight balance of the vehicle seems not to be considered sufficiently. Therefore, there is room for improvement in the steering stability and the kinetic performance regarding the structure disclosed in the above-described second patent document as well.

SUMMARY OF THE INVENTION

The present invention has been devised in view of the above-described matters, and an object of the present invention is to provide an electric automobile which can properly optimize the longitudinal weight balance of the vehicle and reduce the yaw moment of inertia, thereby improving the steering stability and the kinetic performance of the vehicle.

The electric automobile of the present invention comprises a tunnel portion provided at a central portion, in a vehicle width direction, of a floor panel, protruding upward and extending in a vehicle longitudinal direction, a battery unit installed in the tunnel portion and including plural batteries which are provided in line along the vehicle longitudinal direction, and a motor provided on a forward or rearward side of the battery unit and operative to drive a driving wheel when receiving electric power from the battery, wherein the battery unit is configured such that weight thereof becomes heavier while being separated from the motor.

According to the present invention, since the floor panel is provided between a front wheel and a rear wheel, i.e., at a middle portion, in the longitudinal direction, of the vehicle, and the tunnel portion of the floor panel is provided at the central portion, in the vehicle width direction, of this floor panel, the heavy object can be positioned near at the center of the vehicle by installing the battery unit in the tunnel portion. Thereby, the yaw moment of inertia can be properly reduced. Further, since the battery unit is configured such that its weight becomes heavier while being separated from the motor in a case where the motor, another heavy object, is provided on the forward or rearward side of the battery unit, it can be properly prevented that the longitudinal weight balance of the vehicle becomes too forward or rearward.

In the present invention, the battery unit may be configured such that width thereof, in a plan view, becomes wider while being separated from the motor.

According to this structure, the battery unit in which the weight becomes heavier while being separated from the motor can be materialized with a simple structure.

In the present invention, the motor may be provided to overlap at least part of a back portion of a seat disposed at the floor panel in a vehicle side view.

According to this structure, since the motor and the back portion of the seat are close to each other, the yaw moment of inertia can be reduced further.

In the present invention, the electric automobile may further comprise a driveshaft to transmit a rotational force of the motor to the driving wheel. Herein, the motor may be arranged closer to a central portion, in a longitudinal direction, of the automobile than the driveshaft.

According to this structure, since the motor can be arranged between the front wheel and the rear wheel, a layout with an appropriate longitudinal weight balance of the vehicle can be obtained.

In the present invention, a left-side seat and a right-side seat may be provided at the floor panel on a left side and a right side of the tunnel portion, respectively. Herein, width of a part of the battery unit which is positioned between the left-side seat and the right-side seat may be set to be narrower than that of another part of the battery unit which is positioned on a vehicle forward side of the left-side seat and the right-side seat.

According to this structure, the width of each of the left-side seat and the right-side seat can be secured sufficiently by relatively narrowing the part of the battery unit positioned between the left-side seat and the right-side seat, without expanding the vehicle width. Thereby, a sitting space for a passenger seated in the left-side seat or the right-side seat can be secured sufficiently.

In the present invention, the electric automobile may further comprise a dash panel extending from a front-end portion of the floor panel upward and in the vehicle width direction. Herein, a front-end portion of the battery unit may be positioned on a vehicle rearward side of the dash panel.

According to this structure, since the front-end portion of the battery unit is positioned inside the tunnel portion, the yaw moment of inertia can be reduced more.

In the present invention, the motor may be provided on a vehicle rearward side of the battery unit, the tunnel portion may be configured such that protrusion height thereof from a level of the floor panel becomes higher while going vehicle forward, and further the battery unit may be configured such that height thereof becomes higher while going vehicle forward in accordance with the protrusion height of the tunnel portion.

According to this structure, since the motor is provided on the vehicle rearward side of the battery unit, the battery unit is configured such that its weight becomes heavier while going vehicle forward. Further, since the protrusion height of the tunnel portion from the floor panel becomes higher while going vehicle forward and also the height of the battery unit becomes higher while going vehicle forward in accordance with the protrusion height of the tunnel portion, the layout of the above-described battery unit's configuration that the weight becomes heavier while being separated from the motor can be simple.

In the present invention, a seat may be provided at a portion of the floor panel which is positioned beside the tunnel portion, and an upper-end portion of the tunnel portion may be located at a higher level than an upper face of a seat cushion of the seat.

According to this structure, since the height of the tunnel portion can be secured sufficiently, the installation space of the battery in the tunnel portion can be large.

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

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a left-side view of an electric automobile according to an embodiment of the present invention.

FIG. 2 is a plan view of the electric automobile according to the embodiment of the present invention.

FIG. 3 is a plan view showing a cabin in a state where a roof, a door, an interior material and others of the electric automobile are omitted.

FIG. 4 is a sectional view taken along line IV-IV of FIG. 3.

FIG. 5 is a sectional view taken along line V-V of FIG. 3.

FIG. 6 is a perspective view showing a battery unit installed on a vehicle body only.

DETAILED DESCRIPTION OF THE INVENTION

Hereafter, an embodiment of the present invention will be described specifically referring to the drawings. Herein, the embodiment described below is just an exemplified one of the present invention, and therefore it does not to intend to restrict any application or use of the present invention.

FIGS. 1 and 2 respectively show an exterior of an electric automobile 1 which is provided with a vehicle-body structure A according to the embodiment of the present invention. In the description of the present embodiment, a vehicle forward side will be just referred to as the “front (forward) side,” a vehicle rearward side will be just referred to as the “rear (rearward) side,” a vehicle leftward side will be just referred to as the “left (leftward) side,” and a vehicle leftward side will be just referred to as the “left (left) side.” A lateral direction of the vehicle corresponds to (matches) a vehicle with direction. A side view of the vehicle means a view of the vehicle when the electric automobile 1 is viewed from the left side or the right side. Further, a view of the vehicle when the electric automobile 1 is viewed from an upper side means a top view or a plan view of the vehicle.

The electric automobile 1 is a passenger car, for example, and may be any type of vehicle, such as a coupe type, a hatch-back type, or a sedan type. The electric automobile 1 has a hood (bonnet hood) 2 at its front side. A front-side baggage loading space R1 where baggage can be loaded (illustrated by a broken line in FIG. 1 only) is provided below the hood 2. The front-side baggage loading space R1 is opened by opening the hood 2, so that the baggage can be loaded or unloaded.

A rear hood 3 is provided at a rear side of the electric automobile 1. Below the rear hood 3 is provided a rear-side baggage loading space R2 where baggage can be loaded (illustrated by a broken line in FIG. 1 only). The rear-side baggage loading space R2 is opened by opening the rear hood 3, so that the baggage can be loaded or unloaded. Herein, either one or both of the front-side baggage loading space R1 and the rear-side baggage loading space R2 may be set as a space for arranging an auxiliary device therein.

A left-side door 4 and a right-side door 5 are provided to be openable at a left-side portion and a right-side portion of the electric automobile 1. The roof 6 may be a fixed type, a detachable type, or a foldable type. In a case of the detachable type of the holdable type, the vehicle is an open car with no top above a passenger.

The vehicle-body structure A of the electric automobile 1 is equipped with front wheels 7 and rear wheels 8, and a motor M for driving the rear wheels 8 (shown in FIGS. 4 and 5 and hereafter, referred to as the “motor M” simply) is provided. An inverter circuit and various sensors which are necessary for controlling the motor M, devices for driving operation, and others can be used from any conventionally well-known ones.

While the rear wheel 8 is the driving wheel in the present embodiment, the front wheel 7 may be set as the driving wheel, or both of those 7, 8 may be set as the driving wheels. That depends on how the motor M is arranged. That is, in a case where the motor M is installed at the rear side of the vehicle only, the rear wheel 8 can be the driving wheel, and also in a case where the motor M is installed at the front side of the vehicle only, the front wheel 7 can be the driving wheel. Further, in a case where the plural motors M are installed at the front side and the rear side of the vehicle, the both of the wheels 7, 8 can be the driving wheel. Hereinafter, the case where the motor M is installed at the rear side of the vehicle only will be described.

As shown in FIG. 1, a cabin R3 as a space for passengers is provided between the front wheels 7 and the rear wheels 8. As shown in FIG. 4, the vehicle-body structure A of the electric automobile 1 comprises a floor panel 10 which forms a floor face of the cabin R3 and a dash panel 20 which forms a front wall of the cabin R3. Further, the vehicle-body structure A comprises an inclined panel 16 which extends obliquely upward-and-rearward from a rear-end portion of the floor panel and a rear panel 17 which extends rearward from an upper-end portion of the inclined panel 16.

A tunnel portion 11 which protrudes upward and extends in a longitudinal direction is formed at a central portion, in a vehicle width direction, of the floor panel 10. Respective cabin-side faces of the tunnel portion 11, the floor panel 10, and the dash panel 20 are covered with an interior material, not illustrated. As shown in FIG. 3, the vehicle-body structure A further comprises a right-side side sill 12 which extends in the longitudinal direction along a right edge portion of the floor panel 10 and a left-side side sill 13 which extends in the longitudinal direction along a left edge portion of the floor panel 10.

A front-end portion of the tunnel portion 11 is positioned at a front-end portion of the floor panel 10, and a rear-end portion of the tunnel portion 11 is positioned at a rear-end portion of the floor panel 10. Accordingly, the tunnel portion 11 is continuous from the front-end portion to the rear end of the floor panel 10.

This electric automobile 1 is right-hand drive. Therefore, the vehicle-body structure A is equipped with an assistant driver's seat 30 as a left-side seat and a driver's seat 40 as a right-side seat, which are respectively provided on a left side and a right side of the tunnel portion 11 formed at the floor panel 10. Specifically, the assistant driver's seat 30 is arranged on the left side of the tunnel portion 11 at the floor panel 10, and this assistant driver's seat 30 is disposed between the tunnel portion 11 and the left-side side sill 13. The driver's seat 40 is arranged on the right side of the tunnel portion 11 at the floor panel 10, and this driver's seat 40 is disposed between the tunnel portion 11 and the right-side side sill 12. Accordingly, the assistant driver's seat 30 and the driver's seat 40 are provided side by side in the vehicle width direction, interposing the tunnel portion 11 therebetween. Herein, the electric automobile 1 may be left-hand drive, and in this case, the driver's seat 40 may be provided at the left side and the assistant driver's seat 30 may be provided at the right side. Further, a rear seat may be provided as well.

The driver's seat 40 comprises a cushion portion 41 which mainly supports a buttock portion and a thigh portion of the passenger and a back portion 42 which extends upward from a rear end portion of the cushion portion 41 and mainly supports a waist portion, a back portion, and shoulder portions of the passenger. The cushion portion 41 forms a sitting face of the driver's seat 40. Likewise, the assistant driver's seat 30 comprises a cushion portion 31 and a back portion 32. In FIG. 3, a hip point of the passenger seated in the driver's seat 40 is denoted by a reference character HP1, and a hip point of the passenger seated in the assistant driver's seat 30 is denoted by a reference character HP2. Herein, while it is assumed that the passenger seated has a standard body size and weight, each position of the hip points HP1, HP2 does not move so much even when the body size and weight of the passenger changes. In FIG. 4, the hip point of the passenger seated in the assistant driver's seat 30 is denoted by the reference character HP2.

Herein, in a case where the driver's seat 40 is attached to the floor panel 10 such that it is slidable in the longitudinal, the hip point HP1 moves in the longitudinal direction according to its slide position. However, the hip point HP1 where the driver's seat 40 is located at a position where the passenger with the standard body size can take a standard driving position can be made standard. The hip point HP2 on the assistant-driver's-seat 30 side is the same as well. The assistant driver's seat 30 may be fixedly attached to the floor panel 10 without being slidable in the longitudinal direction.

An upper end portion of the tunnel portion 11 is located at a higher level than each upper face of the cushion portions 31, 41. Thereby, a installation space where a center battery unit BY1 described later is installed in the tunnel portion 11 can be securely expanded in a height direction.

As shown in FIGS. 4 and 5, the protrusion height of the tunnel portion 11 from the level of the floor panel 10 (the protrusion height from the level of a portion where the assistant driver's seat 30 and the river's seat 40 are attached) becomes higher while going vehicle forward. Accordingly, the upper end portion of the tunnel portion 11 is inclined gently such that its rear side becomes low. The assistant driver's seat 30 and the driver's seat 40 are positioned beside a rear-side portion of the tunnel portion 11, and the rear-side portion of the tunnel portion 11 overlaps the assistant driver's seat 30 and the driver's seat 40 in a side view. Since the height of the overlapping portion of the tunnel portion 11 with the assistant driver's seat 30 and the driver's seat 40 in the side view becomes low, it becomes possible that the passenger (driver) seated in the driver's seat 40 moves onto the assistant driver's seat 30 beyond the tunnel portion 11, or the passenger seated in the assistant driver's seat 30 moves onto the driver's seat 40 beyond the tunnel portion 11.

Further, as shown in FIG. 3, the width (lateral size) of the tunnel portion 11 becomes wider while going forward. Specifically, the distance between the left-side wall and the right-side wall of the tunnel portion 11 becomes narrower while going rearward, and the width of the rear-side portion of the tunnel portion 11 is narrower than that of a front-side portion of the tunnel portion 11. Since the width of the overlapping portion of the tunnel portion 11 with the assistant driver's seat 30 and the driver's seat 40 in the side view is narrow, the sufficient width of each of the assistant driver's seat 30 and the driver's seat 40 can be secured, suppressing the vehicle width from being improperly wide.

Herein, since the front portion of the tunnel portion 11 is a portion which does not overlap the assistant driver's seat 30 and the driver's seat 40 in the side view, there is no problem in securing the width of the assistant driver's seat 30 and the driver's seat 40 by enlarging the width of the front portion of the tunnel portion 11.

The dash panel 20 extends upward and in the vehicle width direction from the front-end portion of the floor panel 10, and is a member to partition the cabin R3 from its font-side space. A protrusion portion 20a which protrudes toward an inside of the cabin R3 is provided at a central portion, in the vehicle width direction, of the dash panel 20. As shown in FIG. 5, a lower-end portion of the protrusion portion 20a is continuous to the front-end portion of the tunnel portion 11.

As shown in FIGS. 3-6, the vehicle-body structure A comprises the center battery unit BY1, an assistant-driver's-seat side battery unit BY2, a rear-right side battery unit BY3, and a rear-left side battery unit BY4. In the present embodiment, the plural battery units BY1-BY4 are arranged at various portions of a vehicle body, so that the installation quantity (volume, capacity) of the battery can be increased by utilizing plural spaces formed at the various portions of the vehicle body.

The center battery unit BY1 is installed in the tunnel portion 11. In the tunnel 11, a center-battery arrangement portion (second battery arrangement portion) 11A to install the center battery unit BY1 is provided to extend in the longitudinal direction, and the center battery unit BY1 arranged at the center-battery arrangement portion 11A is detachably attached to the floor panel 10 or the like (in a replaceable manner). A front-end portion of the center battery unit BY1 in its fixed state to the floor panel 10 or the like is positioned on a rearward side of the dash panel 20. Thereby, any battery as a heavy object does not exist at the front-side portion of the vehicle.

The center battery unit BY1 includes plural batteries (center batteries) B1 which are provided in line along the longitudinal direction, and these batteries B1 supply electric power to the motor M. The motor M drives the rear wheels 8 by receiving the electric power from the center battery unit BY1. The center battery unit BY1 may comprise a battery case to install the center batteries B1, a sensor to detect the temperature of the center batteries B1, a heat exchanger to adjust the temperature of the center batteries B1, and others, which are not illustrated.

The center battery B1 is made of a chargeable/dischargeable secondary battery (battery cell) or the like. However, this battery B1 may be made of a lithium-ion battery, a solid-state battery, or the like. Any other secondary battery is applicable. The center battery B1 may be a so-called battery cell or a battery pack to store battery cells. While the drawings illustrate the center battery B1 in a rectangular-parallelepiped shape, but this is not limited to this shape. Further, the center batteries B1 are all the same.

The motor M drives the rear wheels 8, and therefore it is provided at a rear side of the vehicle body, specifically, on the rearward side of the center battery unit BY1. The center battery unit BY1 is configured such that its weight becomes heavier while being separated from the motor M, i.e., while going forward. For example, as shown in FIG. 3, the center battery unit BY1 is configured such that its width (its lateral size), in the top view, becomes wider while being separated from the motor M. Specifically, the center batteries B1 constituting the center battery unit BY1 are disposed in line in the vehicle longitudinal direction which corresponds to (match) a batteries' longitudinal direction. The foremost-positioned center batteries B1 are arranged such that three of batteries are in line in the vehicle width direction. The second-positioned center batteries B1 are arranged such that two of batteries are in line in the vehicle width direction. The third-positioned, fourth-positioned, and rearmost-positioned center batteries B1 are respectively arranged such that a single line of batteries extends in the longitudinal direction. That is, those batteries B1 are not in line in the vehicle width direction.

Further, the center battery unit BY1 is configured such that the size, in a vertical direction, thereof becomes longer while being separated from the motor M. As shown in FIG. 5, the foremost-positioned center batteries B1 and the second-positioned center batteries B1 are arranged such that four of batteries are in line in the vehicle direction. The third-positioned center batteries B1 and the fourth-positioned center batteries B1 are arranged such that three of batteries are in line in the vehicle direction. The rearmost-positioned center batteries B1 are arranged such that two of batteries are in line in the vehicle direction. The number of the center batteries B1 stacked in the vertical direction can be also called a stack number or a step number.

That is, the center batteries B1 are arranged such that the width of the center battery unit BY1 becomes wider while being separated from the motor M and, that the size, in the vertical direction, of the center battery unit BY1 becomes longer while being separated from the motor M. Accordingly, the front-end portion of the center battery unit BY1 is the heaviest and a rear-end portion of the center battery unit BY1 is the lightest. A middle portion, in the longitudinal direction, of the center battery unit BY1 has a middle weight between the weight of the front-end portion and the weight of the rear-end portion.

The assistant driver's seat 30 and the driver's seat 40 are positioned beside the third-positioned, fourth-positioned and rearmost-positioned center batteries B1 of the center battery unit BY1. Meanwhile, the foremost-positioned and second-positioned center batteries B1 of the center battery unit BY1 are arranged on the forward side of the assistant driver's seat 30 and the driver's seat 40. That is, since the center batteries B1 of the center battery unit BY1 are not arranged in line in the vehicle width direction between the assistant driver's seat 30 and the driver's seat 40, the width of the portion of the center battery unit BY1 where the center batteries B1 are not arranged in line is set to be narrower than that of the portion of the center battery unit BY1 which is positioned on the forward side of the assistant driver's seat 30 and the driver's seat 40. The width of the center battery unit BY1 becomes narrower while going rearward, corresponding to the width of the tunnel portion 11.

Further, the stack (step) number of the foremost-positioned and second-positioned center batteries B1 of the center battery unit BY1 is the most, the stack (step) number of the third-positioned and fourth-positioned center batteries B1 is fewer, and the stack (step) number of the rearmost-positioned center batteries B1 is the fewest. Thereby, the center battery unit BY1 is configured such that its height becomes higher while going forward, corresponding to the protrusion height of the tunnel portion 11.

The number, the longitudinally-arranged number, and the stack number of the center batteries B1 constituting the center battery unit BY1 are not limited to the above-described ones, and any number is applicable. That is, as long as those numbers of the center batteries B1 are appropriately set such that the battery unit BY1 becomes heavier while being separated from the motor M, any number more than two (including two) is applicable as the longitudinally-arranged number and also any number more than one (including one) is applicable as the stack number.

The assistant-driver's-seat side battery unit BY2 is arranged at a portion of the floor panel 10 which is positioned on the forward side of the cushion portion 31 of the assistant driver's seat 30. The assistant-driver's-seat side battery arrangement portion (third battery arrangement portion) 11B where the assistant-driver's-seat side battery unit BY2 is arranged is provided on the forward side of the assistant driver's seat 30. Specifically, the assistant-driver's-seat side battery unit BY2 is arranged at a rear-side portion of the floor panel 10 which is positioned on the assistant-driver's-seat side, whereas a front-side portion of the floor panel 10 which is positioned on the assistant-driver's-seat side is set as a foot-placement portion 10a where feet of the passenger seated in the assistant driver's seat 30 are placed. The passenger having the standard body size seems not to place the passenger's feet just before the cushion portion 31 of the assistant driver's seat, but this passenger tends to place the feet forward away from the cushion portion 31, stretching the passenger's legs. In the present embodiment, since the assistant-driver's-seat side battery unit BY2 does not exist at the portion forward away from the cushion portion 31 and also the foot-placement portion 10a is provided, the comfortableness of the passenger seated in the assistant driver's seat 30 can be improved, installing the batteries B2 on the side of the assistant driver's seat 30.

A positional relationship of the assistant-driver's-seat side battery unit BY2 and the hip point HP1 of the passenger seated in the driver's seat 40 will be described. The assistant-driver's-seat side battery unit BY2 is positioned on the forward side of the hip point HP1 of the passenger seated in the driver's seat 40. In FIG. 3, a gravity center of the assistant-driver's-seat side battery unit BY2 is denoted by a reference character P1, whereas the center of the vehicle (in the longitudinal direction and in the width direction) is denoted by a reference character P2. In the plan (top) view, the hip point HP1 of the passenger seated in the driver's seat 40, the vehicle center (P2), and the gravity center (P1) of the assistant-driver's-seat side battery unit BY2 are positioned on an identical liner (straight) line (illustrated by an imaginary line L). This imaginary line L is inclined, in the plan view, such that its rear side is located on the side of the driver's seat 40.

The assistant-driver's-seat side battery unit BY2 includes the assistant-driver's-seat side batteries B2 like the center batteries B1 which constitutes the center battery unit BY1. The assistant-driver's-seat side batteries B2 are operative to supply the electric power to the motor M as well. The assistant-driver's-seat side battery unit BY2 may comprise a battery case, a sensor to detect the temperature of the assistant-driver's-seat side batteries B2, a heat exchanger to adjust the temperature of the assistant-driver's-seat side batteries B2, and others.

An upper-end portion of the assistant-driver's-seat side battery unit BY2 is located at a lower level than an upper face of the front-end portion of the cushion portion 31 of the assistant driver's seat 30. The assistant-driver's-seat side battery unit BY2 is configured such that its level becomes lower while going forward. That is, three of the assistant-driver's-seat side batteries B2 are in line in the longitudinal direction, and the stack (step) number of the foremost-positioned assistant-driver's-seat side batteries B2 is one, whereas the stack (step) number of the second-positioned and rearmost-positioned assistant-driver's-seat side batteries B2 is two. The height of the upper-end portion of the upper-stacked assistant-driver's-seat side batteries B2 is located at the lower level than the upper face of the front-end portion of the cushion portion 31 of the assistant driver's seat 30. Thereby, the assistant-driver's-seat side battery unit BY2 may not contact easily a back face of the thigh portion of the passenger or the like, so that the comfortableness of the passenger seated in the assistant driver's seat 30 can be improved. Herein, the assistant-driver's-seat side batteries B2 is covered with a battery cover 50 (shown in FIG. 4 only). The battery cover 50 may be made of a soft material, such as cloth or synthetic leather, or a hard resign material. The battery cover 50 may be a member which constitutes part of the assistant-driver's-seat side battery unit BY2.

The foremost-positioned assistant-driver's-seat side batteries B2 is a front-side battery, and the rearmost-positioned assistant-driver's-seat side batteries B2 is a rear-side battery. The rearmost-positioned assistant-driver's-seat side batteries B2 are the two-stack batteries, and the foremost-positioned assistant-driver's-seat side batteries B2 are the one-stack batteries. Accordingly, the rearmost-positioned assistant-driver's-seat side batteries B2 is higher than the foremost-positioned assistant-driver's-seat side batteries B2.

Further, in the present embodiment, the hip point HP2 of the passenger seated in the assistant's seat 30 is set to be lower than an upper face of a rear side of the assistant-driver's-seat side batteries B2. That is, legs of the passenger seated in the assistant driver's seat 30 take a shape such that their front sides become higher while approaching their knees from the hip point HP2. By setting the level of the upper face of the rear side of the assistant-driver's-seat side batteries B2 above the hip point HP2 according to this shape of the passenger's legs, the installation quantity of the assistant-driver's-seat side batteries B2 can be increased.

The number, the longitudinally-arranged number, and the stack number of the assistant-driver's-seat side batteries B2 constituting the assistant-driver's-seat side battery unit BY2 are not limited to the above-described ones, and any number is applicable. That is, as long as those numbers of the assistant-driver's-seat side batteries B2 are appropriately set such that the height of the assistant-driver's-seat side battery unit BY2 becomes lower while going forward, any number more than two (including two) is applicable as the longitudinally-arranged number and also any number more than one (including one) is applicable as the stack number. The assistant-driver's-seat side batteries B2 may be positioned such that its longitudinal direction matches the vehicle width direction or the vehicle longitudinal direction.

The assistant-driver's-seat side battery unit BY2 is detachably installed on the vehicle body, i.e., on the floor panel 10. Specifically, as shown in FIG. 4, an attaching/detaching mechanism 14 of the assistant-driver's-seat side battery unit BY2 is provided at the floor panel 11 on the side of the assistant driver's seat 30. The attaching/detaching mechanism 14 comprises a body portion 14a which is fixed to the floor panel 10 on the side of the assistant driver's seat 30 and an engagement portion 14b which is provided at the body portion 14a and engages with the assistant-driver's-seat side battery unit BY2. The engagement portion 14b is configured to move between an engaging position where it engages with the assistant-driver's-seat side battery unit BY2 and an un-engaging position where it is released from the assistant-driver's-seat side battery unit BY2. By shifting the engagement portion 14b to the engaging position in a state where the assistant-driver's-seat side battery unit BY2 is installed, the assistant-driver's-seat side battery unit BY2 comes to be fixed to the floor panel 10 so that it cannot be moved by vibrations during vehicle traveling or the like. Meanwhile, when the assistant-driver's-seat side battery unit BY2 is detached from the vehicle, the engagement portion 14b is shifted to the un-engaging position from the engaging position.

The attaching/detaching mechanism 14 of the assistant-driver's-seat side battery unit BY2 can be provided as needed. Further, the structure of the attaching/detaching mechanism 14 is not limited to the above-described one, and any type of structure, such as an attaching structure where the assistant-driver's-seat side battery unit BY2 is fastened to the floor panel 10 or a bracket (not illustrated) or the like by using screws or a band, or an engaging structure where a hook is used, is applicable.

In a case where the electric automobile 1 gives higher priority to the light weight than the traveling distance, for example, the electric automobile 1 can be traveled without the assistant-driver's-seat side battery unit BY2. Further, the assistant-driver's-seat side battery unit BY2 can be also detached in order to secure the sufficient sitting space for the passenger seated in the assistant driver's seat 30. The assistant-driver's-seat side battery unit BY2 may be detached for the higher priority of the longitudinal or lateral weight balance than the traveling distance of the electric automobile 1. In this case, since the weight balance of the electric automobile 1 can be adjected by using the assistant-driver's-seat side battery unit BY2, the assistant-driver's-seat side battery unit BY2 can be used as part of a weight-balance adjusting means. Moreover, part of the plural assistant-driver's-seat side batteries B2 constituting the assistant-driver's-seat side battery unit BY2 may be configured to be detachable. Additionally, the plural assistant-driver's-seat side batteries B2 constituting the assistant-driver's-seat side battery unit BY2 may be divided into plural groups, and their groups may be configured to be detachable separately.

As shown in FIGS. 3 and 5, the motor M is attached to a subframe 80 which is provided below a rear portion of the vehicle body, and it is arranged below the inclined panel 16 and the rear panel 17 at a middle portion, in the vehicle width direction, of the vehicle body. The motor M is arranged such that its output shaft M1 extends in the longitudinal direction. In the present embodiment, the output shaft M1 of the motor M projects rearward. A front-side portion of the motor M is arranged in the tunnel portion 11. Thus, since the installation position of the motor M is set to be as forward as possible, the motor M is arranged such that it overlaps at least part of the back portion 32 of the assistant driver's seat 30 in the side view shown in FIG. 4. In the side view, for example, the motor M can be arranged such that a lower-side portion of the back portion 32 and the front-side portion of the motor M overlap each other. Thereby, the motor M can be positioned near the center of the vehicle.

The vehicle-body structure A comprises a left-side drive shaft 60 and a right-side drive shaft 61 which are provided in back of the tunnel portion 11 formed at the floor panel 10 and transmit a rotational force of the motor M to the rear wheels 8 as the driving wheels. The left-side drive shaft 60 and the right-side drive shaft 61 extend in the vehicle width direction. The motor M is provided between the tunnel portion 11 and the left-side and right-side drive shafts 60, 61. Accordingly, the motor M is arranged closer to the central portion, in the longitudinal direction, of the vehicle than the drive shafts 60, 61. Herein, in a case where the motor is provided at the front side and drive the front wheels 7, which is not illustrated, the left-side and right-side drive shafts can be provided in front of the tunnel portion 11.

The vehicle-body structure A further comprises a transmission 62 and a deferential gear box 63. The transmission 62 and the deferential gear box 63 are attached to the sub frame 80. The transmission 62 and the deferential gear box 63 are arranged behind the motor M and on the side of the driver's seat 40 at the vehicle body. The rotational force of the output shaft M1 of the motor M is inputted to the transmission 62 via a gear 64. The rotational force of the output shaft M1 extending in the longitudinal direction is transferred to a rotational force around an axis extending in the vehicle width direction and inputted to the transmission 62. The transmission 62 is a speed-changing gear or a speed-reducing gear. In a case where the transmission 62 is the speed-changing gear, it may be a stepped transmission or a non-stage transmission. The transmission 62 and the deferential gear box 63 may be integrated, or gears to constitute a transmission and gears to constitute a deferential mechanism may be installed in a single gear box. The motor M and the transmission 62 may be modularized. Herein, in a case where the motor M is provided at the front side of the vehicle body and drives the front wheels 7, the transmission 62 and the deferential gear box 63 can be provided in front of the tunnel portion 11, which is not illustrated.

The rotational force of the motor M which is outputted from the transmission 62 is transferred to the right-and-left rear wheels 8 via a deferential mechanism (not illustrated) stored in the deferential gear box 63 and the drive shafts 60, 61.

As shown in FIG. 3, the rear-right side battery unit BY3 is provided behind the driver's seat 40. The inclined panel 16 is positioned in back of the driver's seat 40, and a rear-right side battery arrangement portion (first battery arrangement portion) 11C where the rear-right side battery unit BY3 can be arranged is provided in back of the inclined panel 16 (outside the cabin R3). The rear-right side battery unit BY3 comprises plural rear-right side batteries B3 like the center batteries B1 constituting the center battery unit BY1. The rear-right side batteries B3 are operative to supply the electric power to the motor M as well. The rear-right side battery unit BY3 may comprise a battery case, a sensor to detect the temperature of the rear-right side batteries B3, a heat exchanger to adjust the temperature of the rear-right side batteries B3, and others.

Further, the rear-left side battery unit BY4 is provided behind the assistant driver's seat 30. The inclined panel 16 is positioned in back of the assistant driver's seat 30, and a rear-left side battery arrangement portion (first battery arrangement portion) 11D where the rear-left side battery unit BY4 can be arranged is provided in back of the inclined panel 16 (outside the cabin R3). The rear-left side battery unit BY4 comprises plural rear-left side batteries (rear batteries) B4 like the center batteries B1 constituting the center battery unit BY1. The rear-left side batteries B4 are operative to supply the electric power to the motor M as well. The rear-left side battery unit BY4 may comprise a battery case, a sensor to detect the temperature of the rear-left side batteries B4, a heat exchanger to adjust the temperature of the rear-left side batteries B4, and others.

The rear-right side battery arrangement portion 11C and the rear-left side battery arrangement portion 11D are provided relatively on the forward side of the transmission 62. The rear-right side battery arrangement portion 11C and the rear-left side battery arrangement portion 11D are further provided on the both sides, in the vehicle width direction, of the motor M. That is, the motor M is arranged between the rear-right side batteries B3 and the rear-left side batteries B4, and also provided such that at least part of the rear-right side batteries B3 and the rear-left side batteries B4 overlap the motor M in the side view. Since the rear-right side batteries B3 and the rear-left side batteries B4 are provided at the both sides, in the vehicle width direction, of the motor M, respectively, these can be called side batteries.

The number, the longitudinally-arranged number, and the stack number of the rear-right side batteries B3 constituting the rear-right side battery unit BY3 can be set arbitrarily. Further, the number, the longitudinally-arranged number, and the stack number of the rear-left side batteries B4 constituting the rear-left side battery unit BY4 can be set arbitrarily as well. The rear-right side batteries B3 and the rear-left side batteries B4 may be arranged such that their longitudinal direction match the vehicle width direction or the longitudinal direction. Further, the rear-right side battery unit BY3 and the rear-left side battery unit BY4 may be detachable.

Effects of Embodiment

According to the vehicle-body structure A of the electric automobile 1 of the present embodiment, since the floor panel 10 is provided between the front wheels 7 and the rear wheels 8, i.e., at the middle portion, in the longitudinal direction, of the vehicle, and the tunnel portion 11 of the floor panel 10 is provided at the central portion, in the vehicle width direction, of this floor panel 10, the heavy object can be positioned near at the center of the vehicle by installing the center battery unit BY1 in the tunnel portion 11. Thereby, the yaw moment of inertia can be properly reduced. Further, since the center battery unit BY1 is configured such that its weight becomes heavier while being separated from the motor M, it can be properly prevented that the longitudinal weight balance of the vehicle becomes too forward or rearward.

Further, since the assistant-driver's-seat side battery unit BY2 is arranged on the forward side of the cushion portion 31 of the assistant driver's seat 30, the sitting space for the passenger seated in the assistant driver's seat 30 can be secured. Herein, the assistant-driver's-seat side battery unit BY2 is one of the heavy objects because it is operative to supply the electric power to the motor M. However, since the assistant-driver's-seat side batteries B2 is positioned on the vehicle forward side of the hip point HP1 of the passenger seated in the driver's seat 40, the gravity center of the vehicle with no passenger seated in the assistant driver's seat 30 comes to be near the center of the vehicle, so that the yaw moment of inertia can be properly reduced.

Further, when viewed in the vehicle longitudinal direction, the tunnel portion 11 of the floor panel 10, the motor M, and the drive shafts 60, 61 are arranged in line in this order. Accordingly, the motor M of the heavy object is closer to the central portion, in the longitudinal direction, of the vehicle than the drive shafts 60, 61. Moreover, since at least each part of the rear-right side battery unit BY3 and the rear-left battery unit BY4 overlaps the motor M in the side view, the battery units BY3, BY4 are closer to the central portion, in the longitudinal direction, of the vehicle than the drive shafts 60, 61. Therefore, an effective layout for the yaw moment of inertia, including the rear-right side battery unit BY3 and the rear-left battery unit BY4, can be attained. Additionally, since the rear-right side battery unit BY3 and the rear-left battery unit BY4 are provided in a space before the drive shafts 60, 61, the sufficient installation quantity of the battery can be secured.

The above-described embodiment just shows an exemplified sample of the present invention, and therefore the present invention should not be construed based on this embodiment. Any modification or change is applicable within the scope of the claims of the present invention. For example, either one of the rear-right side battery unit BY3 and the rear-left battery unit BY4 may be provided only. The motor M may be disposed on the left side or on the right side of the vehicle body. The motor M may be arranged such that its output shaft M1 extends in the vehicle width direction.

As described above, the present invention is usable for the electric automobile in which the motor for drive and the battery are installed.

ELECTRIC AUTOMOBILE

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CPC

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Priority Claims (1)