WO2024070681A1

WO2024070681A1 - Electric vehicle

Info

Publication number: WO2024070681A1
Application number: PCT/JP2023/033314
Authority: WO
Inventors: 政秀 ▲徳▼田
Original assignee: 株式会社Tokuda-Ard
Priority date: 2022-09-26
Filing date: 2023-09-13
Publication date: 2024-04-04
Also published as: JP7214178B1; JP2024047302A

Abstract

The present invention enables a steady supply of power generated through vibratory power generation to a battery. An electric vehicle (1) according to the present invention comprises: a battery (6); first and second drive shafts (10, 11); an electric motor (2) that rotates the first drive shaft (10) through power from the battery; a clutch (3) that switches between a state in which the first and second drive shafts are connected to each other and a state in which the first and second drive shafts are not connected to each other; driving wheels (5); a reduction gear (4) that transmits rotation of the second drive shaft (11) to the driving wheels at a prescribed reduction ratio; and a vibration power generator (8) that is arranged so as to contact an outer circumferential surface of the first drive shaft. A cross section of at least a part of a portion of the first drive shaft in contact with the vibration power generator, the cross section being in the direction orthogonal to the rotation axis of the first drive shaft, is configured by a shape in which the distance from the rotation axis to the outer circumferential surface in not uniform. The battery is charged by power generated by the vibration power generator.

Description

Electric car

The present invention relates to a battery charging device and an electric vehicle, and in particular to a battery charging device for charging the battery of an electric vehicle, and an electric vehicle equipped with such a battery charging device.

In recent years, automobiles that run by driving an electric motor using electricity stored in a battery, such as BEVs (battery electric vehicles), EREVs (range extender electric vehicles), PHEVs (plug-in hybrid electric vehicles), and HEVs (hybrid electric vehicles), have become increasingly popular. In this specification, these types of automobiles are collectively referred to as "electric vehicles."

In an electric vehicle, when the battery is depleted, it can no longer run on electric power. For this reason, electric vehicles in recent years have been equipped with a function to charge the battery using regenerative power from an external power source or the electric motor. Recently, technology has also been proposed that attempts to charge the battery by converting the vibrations of the vehicle body into electricity.

Patent Documents 1 to 3 disclose examples of this type of technology. Patent Document 1 discloses a technology in which a vibration plate and a power generating plate are attached to a tire, and the vibration plate converts the tire's deflection while the tire is moving into pressure, which causes the power generating plate to generate electricity, and the electricity generated charges a battery. Patent Document 2 discloses a technology in which a vibration generator attached to the vehicle body converts vibrations generated while the vehicle is moving into electricity, which then charges a battery. Patent Document 3 discloses a technology in which a piezoelectric element array or electromagnetic induction vibration generator embedded in the tire converts vibrations generated while the vehicle is moving into electricity, which then charges a battery.

JP 2011-062066 A JP 2019-103227 A JP 2022-093421 A

All of the technologies in Patent Documents 1 to 3 generate electricity by using natural vibrations that occur when an electric vehicle is running. When generating electricity using natural vibrations in this way, it is difficult to stably supply power to the battery because the vibrations themselves are not stable.

Therefore, one of the objects of the present invention is to provide a battery charging device and an electric vehicle that can stably supply power generated by vibration power generation to a battery.

The battery charging device according to the present invention is a battery charging device built into an electric vehicle having a battery, an electric motor operated by power from the battery, drive wheels, and a reducer that transmits the rotation of the electric motor to the drive wheels at a predetermined reduction ratio, and includes a drive shaft that transmits the rotation of the electric motor to the reducer, and a vibration generator arranged to be in contact with the outer circumferential surface of the drive shaft, and at least a part of the cross section of the drive shaft in a direction perpendicular to the rotation axis of the drive shaft that contacts the vibration generator is configured with a shape in which the distance from the rotation axis to the outer circumferential surface is not uniform, and the battery is charged with power generated by the vibration generator.

The electric vehicle according to the present invention includes a battery, an electric motor that runs on power from the battery, drive wheels, a reducer that transmits the rotation of the electric motor to the drive wheels at a predetermined reduction ratio, a drive shaft that transmits the rotation of the electric motor to the reducer, and a vibration generator that is arranged in contact with the outer circumferential surface of the drive shaft, and at least a portion of the cross section of the drive shaft that is in contact with the vibration generator and is perpendicular to the rotation axis of the drive shaft is configured with a shape in which the distance from the rotation axis to the outer circumferential surface is not uniform, and the battery is charged with power generated by the vibration generator.

According to the present invention, the stable motion of the rotation of the drive shaft causes the vibration generator to vibrate, which in turn causes the vibration generator to generate electricity, making it possible to stably supply the electricity generated by vibration power generation to the battery.

1 is a diagram showing a system configuration of an electric vehicle 1 according to a first embodiment of the present invention. 1 is a diagram showing a specific configuration of a drive shaft 10a and a vibration power generator 8 according to a first embodiment of the present invention. FIG. 4 is a diagram showing electrical connections of a plurality of vibration power generation semiconductors 8c included in the vibration power generator 8 according to the first embodiment of the present invention. FIG. 4A to 4C are diagrams showing examples of the cross-sectional shape of a drive shaft 10a. 13 is a diagram showing a specific configuration of a drive shaft 10a and a vibration power generator 8 according to a second embodiment of the present invention. FIG. 7 is a diagram showing the internal configuration and electrical connections of a vibration power generator 8 according to a second embodiment of the present invention. FIG.

Below, an embodiment of the present invention will be described in detail with reference to the attached drawings.

FIG. 1 is a diagram showing the system configuration of an electric vehicle 1 according to a first embodiment of the present invention. As shown in the figure, the electric vehicle 1 is composed of a traction motor 2, a clutch 3, a reduction gear 4, drive wheels 5, a main battery 6, a sub-battery 7, a vibration generator 8, a power amplifier 9,

drive shafts

10 and 11, and an axle 12. Of these, the battery charging device according to this embodiment is composed of the vibration generator 8, the power amplifier 9, and the drive shaft 10.

The traction motor 2 is an electric motor (motor) that runs on power from the main battery 6, and when the accelerator pedal (not shown) is depressed (powered), it converts the electrical energy from the main battery 6 into motive energy to rotate the drive shaft 10. When the accelerator pedal is not depressed and the electric vehicle 1 is not stopped (regenerative), the traction motor 2 converts the kinetic energy transmitted from the drive wheels 5 to the drive shaft 10 into electrical energy (regenerative energy) and charges the main battery 6.

The clutch 3 is a device for switching between a state in which the

drive shafts

10, 11 are connected to each other (connected state) and a state in which the

drive shafts

10, 11 are not connected to each other (disconnected state). Under normal conditions (including when the vehicle is running and when stopped), the clutch 3 is in a connected state, and the

drive shafts

10, 11 rotate as one unit. Therefore, the drive shaft 10 at this time plays the role of transmitting the rotation of the driving motor 2 to the reduction gear 4. On the other hand, in an emergency, such as when an on-board computer (not shown) detects runaway, the clutch 3 goes into a disconnected state and plays the role of separating the drive shaft 11 from the drive shaft 10.

The reduction gear 4 is a device that transmits the rotation of the drive shaft 11 to the axle 12 at a predetermined reduction ratio, and has the role of amplifying the torque of the driving motor 2 to ensure acceleration force when starting, as well as realizing a compact driving motor 2. The reduction gear 4 may be configured so that the reduction ratio can be switched, in which case the reduction gear 4 may be referred to as a "transmission."

The drive wheels 5 are wheels that rotate together with the axle 12. Although only one drive wheel 5 is shown in FIG. 1, an actual electric vehicle 1 is provided with two drive wheels 5 (in the case of front-wheel drive or rear-wheel drive) or four drive wheels 5 (in the case of four-wheel drive). In the case of front-wheel drive, the two drive wheels 5 also serve as steering wheels, and two other wheels are provided in addition to the drive wheels 5. In the case of rear-wheel drive, two steering wheels are provided in addition to the two drive wheels 5.

The main battery 6 is a battery that stores electric power energy for driving the driving motor 2, and is composed of, for example, a lithium-ion battery or a nickel-metal hydride battery. The sub-battery 7 is a battery that stores electric power energy for driving the audio system, SRS airbag system, headlights, wipers, security circuit, etc. (not shown), and is composed of, for example, a lead-acid battery or a lithium-ion battery. The electric power energy stored in the sub-battery 7 is also used to protect a memory (not shown) and to supply standby power during standby. The main battery 6 is charged by electric power energy supplied from an external charger (including those connected to a normal household outlet and dedicated high-speed chargers), regenerative energy supplied from the driving motor 2, and electric power supplied from a power amplifier 9 (described later). The sub-battery 7 is charged by electric power energy supplied from the main battery 6.

The vibration generator 8 is a device that converts vibration energy into electric energy, and is arranged so as to be in contact with the outer circumferential surface of the drive shaft 10. In the following, the part of the drive shaft 10 that is in contact with the vibration generator 8 may be referred to as the "drive shaft 10a" to distinguish it from other parts. As will be described in detail later, the vibration generator 8 is suspended from the ceiling and arranged in a swingable state. In addition, at least a part of the cross section of the drive shaft 10a in a direction perpendicular to the rotation axis of the drive shaft 10 (hereinafter simply referred to as the "cross section") is configured in a shape in which the distance from the rotation axis to the outer circumferential surface is not uniform. By configuring the vibration generator 8 and the drive shaft 10a in this way, when the drive shaft 10 rotates, the vibration generator 8 swings, and as a result, power is generated by the vibration generator 8. The electric energy generated by the vibration generator 8 is amplified by the power amplifier 9 and supplied to the main battery 6.

FIG. 2 is a diagram showing the specific configuration of the drive shaft 10a and vibration generator 8 according to this embodiment. As shown in the figure, the electric vehicle 1 according to this embodiment is configured with a total of two vibration generators 8, one on each side of the drive shaft 10a in the horizontal direction.

As shown in FIG. 2, each of the two vibration power generators 8 is configured to have a protrusion 8a that protrudes toward the drive shaft 10a, a base portion 8b that is a plate-shaped planar member, and multiple vibration power generation semiconductors 8c attached to the surface of the base portion 8b. The protrusion 8a is the portion that comes into contact with the drive shaft 10a. The contact surface of the protrusion 8a with the drive shaft 10a is configured as a smooth convex curved surface so as not to interfere with the rotation of the drive shaft 10a. The upper end of the base portion 8b is suspended from the ceiling 20 by a string 30, which allows the vibration power generator 8 to swing horizontally.

FIG. 3 is a diagram showing the electrical connections of multiple vibration power generation semiconductors 8c included in the vibration power generator 8. As shown in the figure, the multiple vibration power generation semiconductors 8c included in the vibration power generator 8 are connected in series between the positive input terminal and the negative input terminal of the power amplifier 9.

Returning to FIG. 2, the drive shaft 10a in this embodiment is formed so that its cross section forms a rounded triangle (rice ball shape) with its center of gravity at the intersection with the rotation axis C. The outer surface of the drive shaft 10a is formed of a smooth convex curved surface, similar to the surface of the protrusion 8a. By configuring the drive shaft 10a in this way, the vibration generator 8 swings horizontally as the drive shaft 10a rotates (including during power running and regeneration). When the vibration generator 8 swings, electricity is generated by each of the vibration power generation semiconductors 8c therein, and the current generated by the power generation is input to the power amplifier 9. The power amplifier 9 charges the main battery 6 with the current thus input.

A wall surface 21 is provided at a predetermined distance J on the opposite side of each vibration generator 8 from the drive shaft 10a. Here, J is the amplitude of the vibration generator 8 when it oscillates while maintaining contact with the drive shaft 10a. There are no particular limitations on the specific material that constitutes the wall surface 21, and the wall surface 21 may be formed using a partition wall in the engine room, or a dedicated plate-shaped member fixed to the vehicle body. The vibration generator 8 may move away from the drive shaft 10a due to inertia, which would prevent stable oscillation and make the amount of power generated by each vibration power generation semiconductor 8c unstable. By providing the wall surface 21, it is possible to prevent the vibration generator 8 from moving away from the drive shaft 10a, and stabilize the amount of power generated by each vibration power generation semiconductor 8c.

As described above, the battery charging device according to this embodiment vibrates the vibration generator 8 by the stable movement of the rotation of the drive shaft 10, which causes the vibration generator 8 to generate electricity, making it possible to stably supply the electricity generated by vibration power generation to the main battery 6.

In this embodiment, the cross-sectional shape of the drive shaft 10a is an example of a rounded triangle (rice ball shape) with the intersection with the rotation axis C as the center of gravity, but this shape is not essential, and the cross-sectional shape of the drive shaft 10a may be any shape in which the distance from the rotation axis C to the outer periphery is not uniform.

Figures 4(a) to (c) are diagrams showing examples of the cross-sectional shape of the drive shaft 10a. As also shown in Figure 2, Figure 4(a) shows an example in which the cross-sectional shape is a rounded triangle (rice ball shape) with the intersection with the rotation axis C as the center of gravity. Figure 4(b) shows an example in which the cross-sectional shape is a rounded rectangle with the intersection with the rotation axis C as the center of gravity. Figure 4(c) shows an example in which the cross-sectional shape is a perfect circle with the center of gravity at a position different from the intersection with the rotation axis C. As shown in these examples, the cross-sectional shape of the drive shaft 10a can be a variety of shapes, including a perfect circle.

FIG. 5 is a diagram showing the specific configuration of the drive shaft 10a and vibration generator 8 according to the second embodiment of the present invention. Also, FIG. 6 is a diagram showing the internal configuration and electrical connections of the vibration generator 8 according to this embodiment. The battery charging device according to this embodiment differs from the battery charging device according to the first embodiment in terms of the internal configuration of the vibration generator 8, but is otherwise similar to the battery charging device according to the first embodiment. Therefore, the following explanation will focus on the differences from the battery charging device according to the first embodiment.

As shown in FIG. 5, the vibration generator 8 according to this embodiment is configured to have a protruding portion 8a that protrudes toward the drive shaft 10a, a housing 8d, a plurality of gel-like members 8e, and a plurality of vibration piezoelectric elements 8f. The specific configuration of the protruding portion 8a is as described in the first embodiment. The plurality of gel-like members 8e and the plurality of vibration piezoelectric elements 8f are arranged side by side within the housing 8d.

The arrangement of the gel-like members 8e and the vibration piezoelectric elements 8f in the housing 8d will be specifically described with reference to FIG. 6. Starting from the bottom side of the housing 8d, the gel-like members 8e are stacked in the following order: 6 gel-

like members

8e, 12 vibration

piezoelectric elements

8f, 6 gel-

like members

8e, 12 vibration

piezoelectric elements

8f, 6 gel-

like members

8e, 12 vibration

piezoelectric elements

8f, and 6 gel-like members 8e. Note that the number of gel-like members 8e and vibration piezoelectric elements 8f in each layer is not limited to 6 and 12, respectively. Also, in FIG. 6, the gel-like members 8e and vibration piezoelectric elements 8f in each layer are arranged in a row along the horizontal direction of the drawing, but they may also be arranged in a matrix including the depth direction of the drawing.

Each vibration piezoelectric element 8f is arranged so that it generates electricity when pressure is applied in the vertical direction, and each vibration piezoelectric element 8f is fixed (bonded) to the adjacent gel-like material 8e with adhesive 8g. Electrically, each vibration power generation semiconductor 8c is connected in series between the positive input terminal and the negative input terminal of the power amplifier 9.

By configuring the vibration generator 8 as described above, when the vibration generator 8 oscillates with the rotation of the drive shaft 10a, each gel-like member 8e vibrates, and the resulting pressure generates electricity in each vibration piezoelectric element 8f. The resulting current is then supplied to the main battery 6 via the power amplifier 9, thereby charging the main battery 6.

As described above, the battery charging device according to this embodiment can also vibrate the vibration generator 8 by the stable movement of the rotation of the drive shaft 10, thereby causing the vibration generator 8 to generate electricity, so that the electricity generated by vibration power generation can be steadily supplied to the main battery 6.

The above describes preferred embodiments of the present invention, but the present invention is not limited to these embodiments, and the present invention can be implemented in various forms without departing from the spirit of the invention.

For example, in the first embodiment, vibration power generation is performed using the vibration power generation semiconductor 8c, and in the second embodiment, vibration power generation is performed using the vibration piezoelectric element 8f. However, vibration power generation may be performed using other vibration power generation materials. A highly efficient vibration power generation material may be selected and used from all vibration power generation materials that have already been patented or are already commercially available.

Furthermore, the electric vehicle 1 may be provided with a handle for manually rotating the drive shaft 10. In this way, the main battery 6 can be charged from the vibration generator 8 even when the electric vehicle 1 is stopped, so that in an emergency such as a long traffic jam caused by heavy snow, it is possible to buy as much time as possible before the battery runs out and protect the lives of the occupants.

Reference Signs List 1 Electric vehicle 2 Driving motor 3 Clutch 4 Speed reducer 5 Drive wheel 6 Main battery 7 Sub-battery 8 Vibration power generator

8a Protruding portion

8b Base portion 8c Vibration power generation semiconductor 8d Housing 8e Gel-like member 8f Vibration piezoelectric element 8g Adhesive 9

Power amplifier

10, 11 Drive shaft 10a Part of drive shaft 10 12 Axle 20 Ceiling 21 Wall surface 30 Cord C Rotation shaft of drive shaft 10

Claims

Battery and
First and second drive shafts;
an electric motor that rotates the first drive shaft using electric power from the battery;
a clutch that switches between a state in which the first and second drive shafts are connected to each other and a state in which the first and second drive shafts are not connected to each other;
Drive wheels and
a reduction gear that transmits rotation of the second drive shaft to the drive wheels at a predetermined reduction ratio;
a vibration power generator arranged in contact with an outer circumferential surface of the first drive shaft,
a cross section of at least a part of the first drive shaft in contact with the vibration power generator, the cross section being perpendicular to the rotation axis of the first drive shaft, the cross section being configured to have a shape in which a distance from the rotation axis to an outer circumferential surface is not uniform;
charging the battery with the power generated by the vibration generator;
Electric car.
The shape is a rounded triangle having a center of gravity at the intersection with the rotation axis.
2. The electric vehicle of claim 1.
The vibration power generator is suspended so as to be swingable in the horizontal direction.
3. The electric vehicle according to claim 1 or 2.
a wall surface that prevents the vibration power generator from separating from the outer circumferential surface of the drive shaft;
The electric vehicle of claim 3 further comprising:
The vibration power generator includes one or more vibration power generation semiconductors.
3. The electric vehicle according to claim 1 or 2.
The one or more vibration power generation semiconductors are connected in series.
6. The electric vehicle according to claim 5.
The vibration power generator includes one or more vibration piezoelectric elements each fixed to a gel.
3. The electric vehicle according to claim 1 or 2.
The one or more vibration piezoelectric elements are connected in series.
8. The electric vehicle of claim 7.
a handle for manually rotating the drive shaft;
The electric vehicle of claim 1 or 2, further comprising: